D~~PARTMENT OF THE INTERIOR 

UNITED STATES GEOLOGICAL SURVEY 

GEORG}<~ OTIS SM:ITH, DIRECTOR ' 

PROFESSIONAL PAPER 82 

'THE 

GEOLOGY· ·OF LONG ISLAND 

NEW YORK 

BY 

MYRON L. FULLER 

'V ASHINGTON 

GOVEl'tNl\iENT PRINTING OFFICE 

1914 
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CONTENTS. 

[n trod uction ........................................... · ................................................. . 

Location .................................................................. ; ........................ . 

Geologic relations .................................................................................... . 

Purpose of this investigation ......................................................................... . 

Status of Pleistocene correlation ......................... ·.· ........................................... . 

Results of the work .... : . ............................................................................ . 

~~~fde ;~:~i=:~~~r~~~~~i~d~~~~~~- ·. ~ ~: ~ .· .·.·_ ·. ~:: ~ ~ ~ ~ ~ ~ ~::: :·:: ~ ~:::::::::::: ~:::::::: ~ ~ ~ ~ ~ ~ ~ ~ ~: ~ ~ ~::::::: Development of the geologic literature on Long Island ....................................................... . 

General trend ....................................................................................... . 

Literature from 1750 to 1837 (alluvial phase) .......................................................... . 

Literature from 1837 to 1842 (diluvial phase) ................... · ........................................ . 

Literature from 1843 to 1878 (early paleontologic phase) ......................... : ...................... . 

Literature from 1878 to 1900- (early drift phase) ......................................................... . 

Literature from 1901 to 1908 (later drift phase) ......................................................... . 

Literature of contemporary Pleistocene deposits in New Jersey .......................................... . 

The present report .. : ................................................................................ . 

Physiography .................... , .................... · ..................... ~ ........ , ..... ~ ............... . 

Significance of topography ................... ~ .............................. , ......... ~ ............... . 

G·eneral features ............................................................ : ....................... . 

Form of the island ................................................................................... . 

Agencies involved ............................................................................... . 

East Riyer ............................. , ... , ................................................ : . . . 

North shore scarp ............. ~ ................................................................... . 

Harbors of the north shore ........................................................................ . 

Shore line east of Port Jefferson ............................................. · ...................... . 

Peconic and Gardiners bays ...................................................................... . 

Outline of the south shore ...................................................................... · .. . 

Surface lineaments ................................................................................... . 

Influence of the Cretaceous ......................................................................... . 

Mannetto remnants ........... · ........................................ · ............. ~ ............... . 

Mannetto plateau ......................... : . ...................... : . ........................ . 

Hills of Mannetto graveL .............................................................. · ........ . 

Manhasset surface ............................................................. ' ................... . 

Higher plateaus ........................................................... · .................. . 

Lower plateau or terrace ... · ................................... ~ ................................. . 

Moraines ......................................................... · ....... · ........................ . 

Moraines of stratified drift. .................................................................... . 

Extent and general character ....................................................... : ..... . 

Mqrainal cones ....................................................... : .................. . 

Isolated cones ...................................................................... . 

Confluent cones· ...................................................................... . 

Morainal i-idges .......................................................................... . 

Simple ridges ............................... · ...................... ~ ................... . 

~~~ ~~~1:~~~~~~~. _·. ·_·_ ~ ~ : ~ ~ .·. ·. ·_ ~ ~ ~ ~ ~ ~ : : : : : ': : : : : : : : : : : : : : : : : : : ·: : : : : : : : : : ~ ~ : : : : : : : : : :·: : : : 

Depressed moraines ..................................................................... . 

'l'ill moraines ........................................ ~ ........................................ . 

General features ................................................ · .... · ..................... . 

Moraines due to ice shove and drag ........................................................ . 

Pseudomoraines ................................ ~ ......................... 1 ••• • ••• : •••••••••••• 

III 

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IV CONTEJ:9'"TS. 

' Physiography-Continued. 

Surface lineaments-Continued. 

Outwash deposits ........ ~ .............................................. ·_ ........................ . 

Extent .................................................... : ............ -... -... -.. ---···-·-· 

Outwash deposits adjacent to moraines ....................................................... . 

Simple fans .................. , ......................................................... . 

Confluent fans .......................................................................... . 

Outwash deposits distant from moraines .......................... , ........................... . 

Confluent plains ................................... _ ... __ ...... _ ... _ ... _ ... _ ............. . 

Compound .faM .... ·_ ............................................. _ ............ _ ........... . 

Secondary outwash features ....................................... _ ............ _ ......... . 

Kettles ..................................... , .. -.. -.................................... -... -- .. -----

Kettles of the till moraines ................ · ... _ ........ __ ........ __ .... __ ........ _ ........... . 

Kettles of the stratified moraines ........ _ .............. _ .... _ ...................... _ ........ _·. 

Kettles of the outwash deposits .................................. _ ... -_ ................ ~ ...... . 

Kettles from burled ice blocks .......... , ........................ ·. ·.· ....... ·_ .............. . 

Kettles from projecting ice masses .............. _ .............. -.-.·.·--~ ...................... . 

Formation .................. __ .. _ ............... __ .. ____ ., .... __ .... __ · .. __ .. _ ...... _ .. 

Steepness of sides .................. _- .............................. _ .. -........ ·_ . _ .... ·_ . 

Form ............ __ ........ ____ .... _ ... _ .... _.~ __ .. __ .. ___ ~---_-_-_:.~_·_.' .. _____ .· .. ___ . __ . 

Size ................................. : .. ~ ~ : ~ .... .' .' . : .. -_ ... : ......... ~ ....... _ . , ... ~ . 

Depth ............... _·_ ........................................................... ~. 

Terraced kettles .................... _ ........ : : : : .. : .. : : : ... : : ... ~ . : ... : : .......... . 

Kettle rims ............................. _- .. _ ........ _ .......... ~ .................... ·_ .. 

Double kettles and kettle chains ............ · .... ~ ·_ ·_· ............................. · .......... . 

Kettle valleys ........................................................................... . 

Pitted or kettle plains .................................................................. . 

Kettles of doubtful origin ........ : .. ::.:: ................................................ . 

Kettles of the· Manhasset surface ......... : ................................................... . 

Pseudokettles ............................................ -............... : ............... · .... . 

Valleys ........................................................ · ... ' ......... : : ..... : ; ............ . 

Pre-Mannetto valleys ....... : ... · ............................................................ . 

Valleys in Mannetto gravel ................................................... : ............... . 

Older valleys in the Manhasset formation ..................................... ·.- ................ . 

Valley_s associated with the inoraines ........................................ : . : ..... : .... .-: ... . 

M1nor cb,annels .................................................... -...................... . 

Kettle channels .............. :: ............ : ........ _· ........... _·_· .. :.·_ .... · ...... ~: ..... . 

Outflow channels ........................................... : ·. · .......................... . 

Outer morainal fosse .............................................................. · ...... . 

Inner morainal fosse: ........ .' ................................... _ ... __ ................. . 

Outwash channels.· ............ ~ ..................................................... ' .... ·.· .. . 

Relation to moraines ............. : ........................... ·. ·. ·_· .· ....... .' ......... · ..... :_ .. 

Relation to kettles ...................................................................... . 

Forms of channels ........... ~ . :· .................................. -.· _· .................... . 

Post-Wisconsin valleys .............. : .......... :· ............. ' ....... : ........ · .. ·_ ... · ......... . 

· Nature and extent of erosion . .' ........... ·_ ................................................ . 

Forms of the valleys ..................... · ......... ~ .................... ·.· ................ . 

Amphitheaters .............. : .......... :: ............... : ........................... . 

Notched cliffs ................ ~ ... ~ .................................................. . 

g~~~~:~e~a~~;i~~~~ ~: ·::: ~::: ~ ~-:: ~: ~:: ·: ·::::::::: ~: ·:: ~ ~: :·:::::::::::::::::::::::::: :.:: 

Refilled ravines ............. ~ ....................................................... . 

Inland scarps ...................................... -~ .. : ~ .......... : · ... · .. -........................ . 

Principal examples .. : ................. : .... ~ .. · .................. : ......................... , .. . 

The great inland scarp of western Long Island ............................................... . 

Character ................................. : ................ · . : : ~ · ........................ . 

Origin ............................. : ........................ ·.·: ......................... . 0 Shore bluffs ...................................................... ~ . ~ ~ .......................... . 

Landslides ......................................................... .' .' .- .... · ........ · .............. . 

Causes .................................................... ~ . · ............. : . .... · ............ . 

Work of waves ..... : ................. : ... ' ....................... :.·:: .................... . 

Work of springs ............................. ·. ~ : ...... : ... : . ·. · .. : ......... · ............... . 

Movements of clays .................... ~ .............................. ·: ..... ·• ................ · 

Details of landslides ......................................................................... . 

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CONTENTS. 

Physiography---:Continued. 

-Sub1narine features.· .................................................................... · .............. . 

Long Island Sound ......................................... • ........... : .·. · .... '.:: ................ ~. 

The great Sound valley ....... : .................................. : ' .......................... . 

Later channels .......................................... · ........ · .. · .......................... . 

Conclusions ................................... · ............................................. . 

Submarine channels of the Hudson ................................................................ . 

General conditions ......... : .................... · . .' .. · ....................................... . 

Channel of the continental shelf ........... · ............................. · ................. . 

Hudson River rock channeL ................... · ... ~ ................... · .... : .............. . 

History of the channels ......... · ................ ·. · ............................................ . 

.Agencies of formation ................................................................... . 

Cutting of the 700-foot channeL ......... · ................................ ~ ................ . 

The broad outer depression ................... :: .. ·.:·.~· .. ·.· .......... : ....................... . 

The outer canyon ..........•.............. ~.: ... :.: .................................... . 

Obliteration of the earlier channels ..................................... ·_ ................ . 

Cutting of the· present upper cham:iel .................................... · ................. . 

Filling of the upper channel. ........... .' .. ~::· .. ·.:: : .. : ~ : ... · .............................. . 

Stratigraphic_geology ..................................................................... , ............... . 

Method of mapping.~ ............................................................................... . 

Pre-Cretaceous rocks .................... · .... ~ .......... · ....... : ......... · .. · ... · .. : ..... · ................ . 

Cretaceous system ........................................................... · ........................ . 

Character of the deposits ................................. · ........ , ............................... . 

Distribution of Cretaceous deposits ................ : ............. : ............................... . 

Surface outcrops ......................... : .................................................. . 

Ehn Point .......... : ........................................................ : .. · .......... . 

~ho1naston .............................................. : ............................... . 

\Vest side of Hempstead Harbor .. ~ ........ : ............................................. . 

Glen Cove ................................................................................ . 

Sea Cliff. ............................................ : : . : ............................... . 

J.Jattingtown ................ : .... : ...... : ....................... · ....... · .................. . 

Mill Neck ................. :· .... : : ....... : . ~ ~ ............. · .... · ........................... . 

Center Island ........... : ... : ............................. : ............................ . 

Cold Spring Harbor ... : .. : .. · ........................... · .. , ............................... . 

Lloyd Neck ........................... · ............................................. ~ ... . 

Great Neck, Huntington ........ · ..... : ..... , ...... :: .................................... . 

Little Neck, Huntington ................................................................ . 

Eaton Neck ................. : ........ : ... :.::::.:.:: ..... :· ........ : .................... . 

Northeast of Northport ............ : ................................................... , .. ·. 

Dix Hills ............ : . ................... : ....... : ..................... :::: .............. . 

\~Vyandanch .............................................................. : . ........ · .... . 

Farmingdale and Bethpage ................ ~ ..................................... : ........ . 

MelYille ......................................................... ·: ~ ·. ~ . : . ... : ........... . 

Cretaceous deposits penetrated hy wells ....................................................... . 

Structure of the Cretaceous beds ... : ..... · ................ : .. : ..... ·.·.: .. · ........................ . 

Dip ..................................... : .............................................. . 

Folding and faulting: ....................... : ....... : .................... · ................ . 

Form of the Cretaceous surface ...................... · .. ~ ..... : ............. , .... 1 • ••••••••••••• 

Age of the Cretaceous deposits ...................... :.' ............. : .......... : ............... . 

Stratigraphic evidence ............ · ....... · ... ·. · .... · .. ·.::::: ............................... . 

Fossils ..................................... · .......... : : .... : ........ : . .................. . 

Tertiary(?) system ...... , ........................... , ............................................... . 

Distribution ......................... : ......... · ................... :·: ............................. . 

Eocene (?) series ............................................ : . ......... : .. ·.: ....... : . ......... :. 

Miocene (?) series ......... · ................................................ · ....................... . 

Pliocene (?) series ........................ : . .................................................... . 

Lafayette (?) formation .............................. : . ................... : ................. . 

Quaternary system .......... · ............................................... · .... · ..................... . 

Pleistocene series ....... , ............ :· ... : ............. : ................... : ... · .................. . 

Man~~::e~~~~~~---_·_·_·_· ~ _· _·: _·:::::::::::::::: :·: ·: ·:::: ·::::::: ·::::::: :·: -~ ~::: :·:·:·:·::::::::::::::::::: 

Character ............................... · ... ~ ................. ·. ·. ~-- ·.·:. :•: ........ ... : ...... . 

Source of materiaL ............................... : ............. :.·:.· .................... . 

Relations to older deposits ................... : .......... ::.:. _:_;_-::•. _: ..................... . 

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VI CONTENTS. 

Stratigraphic geology-Continued. 

Quaternary system-Continued. 

Pleistocene series-Continued. 

Mannetto gravel-Continued. Page. 

Structure............................................................................... 81 

Distribution....... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 

· Outcrops in the interior of the island ...................................... ,............ 82 

Melville ................. · ............................... _·. . . . . . . . . . . . . . . . . . . . . . . 82 

South end of Mannetto Hilis...................................................... 82 

Half Hollow Hills. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82 

Dix Hills .................... ·. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82 

Wheatley Hills .... : . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82 

Knobs of the north-shore necks ............... '_ ........................... ·......... 82 

Outcrops on the coast................................................................ 83 

Broken Ground ................. ~ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 

Eaton Neck ......... :........................................................... 83 

Little and Great necks, Huntington . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 

Lloyd Neck..................................................................... 83 

Hempstead Harbor ................... '. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 

Deposits penetrated by wells.......................................................... 84 

Age..................................................................................... 85 

Jameco gra!vel. .............. ·................................................................ 85 

Name................................................................................... 85 

Character ......................................................... ·. . . . . . . . . . . . . . . . . . . . . . 85 

Source of materials ... ·. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 

Relations to older deposits............................................................... 88 

Structure................................................................................ 88 

Distribution ........................................................ ·.................... 89 

Possible surface exposures.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89 

Jacob Hill...................................................................... 89 

Mulford Point. ................................................................. ~ . 89 

Montauk Point ..................................... : . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89 

Hog Neck......................................................................... 8.9 

Gardiners Island ................................................ ·................. 89 

Deposits penetrated by wells ........................................... :............... 90 

Long Island ............................. ~ ...................... ~ . . . . . . . . . . . . . . . . . 90 

Plum, Gull, and Fishers islands ....................... :. . . . . . . . . . . . . . . . . . . . . . . . . . . 91 

Age..................................................................................... 92 

Gardiners clay .............................. ·................................................. 92 

Name ....... ~.......................................................................... 92 

Character. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 

Source of material. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 

Relation to older deposits. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 

Character of the upper contact........................................................... 95 

Structure .... ·.·.......................................................................... 95 

Distribution ................................... :. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96 

Surface exposures.................................................................... 96 

Hempstead Harbor ........................... : . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96 

Rocky Point, Cold Spring Harbor. . .. . . . . .. . . . . .. . . . . . . . .. .. . . . .. . . . . .. . .. . .. .. .. 96 

Lloyd Neck. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96 

Eaton Neck ...... : . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 

Vl oodhull Landing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 

Rocky Point Landing ......................................................... ~.. 97 

· Hallock Landing ............................ : . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 

Roanoke Point ......... ~........................................................ 98 

Jacob Hill...................................................................... 98 

Brown Hills..... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98 

Robins Island .............................................. ·..................... 98 

South shore of Great Peconic Bay. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99 

Hog Neck ............................. J......................................... 99 

Sag Harbor ............................ _. ·. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99 

Montauk......................................................................... 99 

Gardiners Island................................................................. JOO 

Plum Island. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 

Fishers Island ............ : ............................................... ·. . . . . . . . 101 
CONTENTS. VII 

Stratigraphic geology-Continued. 

Quaternary system-Continued. 

· Pleistocene series-Continued. 

Gardiners clay-Continued. 

Distribution-Continued Page. 

Deposits penetrated by wells.......... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102 

1\ge .... : ............... ·. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104 

Jacob sand ............................................................................... :.. 106 

N arne. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106 

Character ......................................................... : . . . . . . . . . . . . . . . . . . . . • 107 

Source of materiaL . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107 

Relation to older deposits................................................................ 107 

Character of the upper contact .............. ~ ........ :..................................... 107 

Structure ............................... ·................................................. 108 

Distribution.............................................................................. 108 

Surface exposures.................................................................... 108 

College Point............... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108 

Port 'Vashington................................................................. 108 

Hempstead Harbor........ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108 

Oyster Bay .............. _._ ................................................. · .... ·. 108 

Lloyd and Eaton necks ............................ ~ ......................... ·...... 109 

Northport to Port Jefferson....................................................... 109 

Port Jefferson to 'Vading River..................................................... 109 

Wading River to Orient Point ....................... _ ............ _ .... _........... 109 

Robins and Shelter islands....................................................... 110 

Gardiners Island. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • . . . . . 110 

South Fluke.................................................................... 111 

Plum Island ....................... · ........................ ·. . . . . . . . . . . . . . . . . . . . . . 111 

Fishers Island ....................................................... __ . . . . . . . . . . . 112 

Deposits penetrated by wells .......................... ~............................... 112 

Age. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113 

Manhasset formation......................................................................... 114 

N arne .......................................... : ................ ·. . . . . . . . . . . . . . . . . . . . . . . . . 114 

Subdivisions .. · .................................... · . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115 

General distribution ......................................................... :........... 115 

Occurrence north of the Harbor Hill moraine........................................... 115 

Western Long Island ...................... : ........................ ·............. 115 

Great and Manhasset necks, North Hempstead..................................... 115 

Hempstead Harbor to Oyster Bay.............. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116 

Oyster Bay to Miller Place................................................. . .. . . . . 116 

Occurrence between the Harbor Hill and Ronkonkoma moraines........................ 116 

Roslyn region ........................... ·......................................... 116 

Huntington region ......................................................... _-_ . . . . . 116 

Smithtown region ..................... ·_ .·. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . 116 

Port Jefferson region ..................... ·........................................ · 116 

Rocky Point region ............................................... :............... 117 

Wading River region............................................................ 117 

Middle Island region· ................................................. : . . . . . . . . . . 117 

Fresh Pond Landing region. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117 

Riverhead region................................................................ 117 

Mattituck region .......................................................... ·....... 117 

North shore from Mattituck Inlet to Orient Point.................................. 117 

Peninsulas of the North Fluke and Shelter Island ........ ··.·........................ 117 

Peninsulas of the South Fluke ...................................... ·.............. 118 

Occurrence south of the Ronkonkoma moraine ...... _._................................. 118 

Hempstead region. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118 

Bethpage region and Half Hollow Hills .............. _.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118 

Wyandanch to Central Islip ........................................... ~........... 118 

Central Islip to·Yaphank........................................................ 118 

Yaphank to Shinnecock Canal ...... _, ................................. ~ . . . . . . . . . . . 118 

Bridgehampton region........ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119 

Amagansett region................................................................ 119 

Deposits penetrated by wells.......... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119 
VTII CONTENTS. 

Stratigraphic geology-Continued. 

Quaternary system-Continued. 

Pleistocene. series-Continued. 

Manhasset fotmation-Continued. 

General distribution-Continued. Page. 

Special features of the distribution of the Manhasset formation .......... ·................ 119 

North-shore belt................................................................ 119 

Middle Island belt ...................................... · .... _._ ............. :.... 120 

South Fluke belt ..................... : ...... :.................................... 121 

Herod gravel member ......... ·........................................................... 121 

Name ................................................................... :............. 121 

Character ........................................................ -.-.:............... 121 

Western Long Island~.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121 

Central and eastern Long Island. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122 

Source of material .................................................. ~ . . . . . . . . . . . . . . . . 123 

· . Western· Long Island ......................... : . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123 

Central and eastern Long Island .. : . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123 

Relation to other deposits ... ·_...... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124 

Structure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124 

Distribution ....................................................... ·: . . . . . . . . . . . . . . . . . . i25 

East River to Little Neck Bay.: .................................................. · 125 

Great and Manhasset necks, North Hempstead . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125 

Hempstead Harbor to Oyster Bay................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125 

Lloyd Neck to Northport........................................................ 125 

Northport to Port Jefferson ...... ~ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • . . . . . . . . . . . . . . . . . 125 

Port Jefferson to Orient Point ............................. · .......... ·_ . . . . . . . . . . . . 126 

Bethpage terrace ......... ·. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126 

Eastern Long Island ................... _-_ ....................... :................. 127 

Rockaway Ridge ......... · ................. : . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127 

South Fluke. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127 

Robins Island .................................................... :.............. 128 

Shelter Island ............ · .................... :................................... 129 

Gardiners Island ................................ _ ............... ·_................ 129 

Plum Island. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129 

F).shers Island. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130 

Deposits penE:trated by wells.......... . .. . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . .. . . . . .. . . . . . . . 130 

Age .................... · .................................................. ·............ 132 

Montauk till member. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132 

N arne.............. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132 

Character ...... · ................................. ·..................................... 132 

General composition .................................... : . . . . . . . . . . . . . . . . . . . . . . . . . 132 

Till and gravel phases...... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • . . . . . . . . . . . . . . . . . . . . . . 133 

Lamination ...................................... ! ........ · . . . . . . . . . . . . . . . . . . . . . . . 133 

Cementation .............. ·_ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133 

Color ................................................ :. . . . . . . . . . . . . . . . . . . . . . . . . . . 133 

Oxidation ............................ ~.·......................................... 134 

Source of materials ............................. ·- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134 

Relation•to other deposits .......................... : .............. '................... 134 

Structure .................................. : . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134 

Distribution.............. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135 

West of Little Neck Bay ................................................... : . .. . . 135 

Great and Manhasset necks, North Hempstead ..... ~ ........ : . . . . . . . . . . . . . . . . . . . . . . 135 

Hempstead Harbor to Oyster Bay ................................... , . . . . . . . . . . . . . . 135 

Lloyd Neck .................. , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136 

West Neck. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137 

Little Neck, Hu.ntington .. , . , , ...... , .... , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137 

Eaton Neck and vicinity.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137 

Fort Salonga ........................ :.:.......................................... 137 

Smithtown Bay region ............... ~. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .137 

Crane Neck and Oldfield points................................................... 137 

Port Jefferson to Wading River ........ -. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138 

Wading River to Fresh Pond Landing .................................. -. . . . . . . . . . . 138 

Friars Head.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138 

Roanoke Landing to Orient Point ............................................ -. . . . . . 139 

East \-Villiston ................................... ·................................. 141 
CONTENTS. IX 

Stratigraphic geology-Continued. 

Quaternary system-Continued. 

· Pleistocene series-Continued. 

Manhasset formation-Continued. 

Montauk till member-Continued. 

Distribution-Continued. Page. 

Half Hollow Hills ............................... :................................. 141 

Middle Island region ......................................... ·..................... 141 

Red Cedar Point.................................................................. 141 

Shinnecock Hills and vicinity ......................... , .................... '....... 142 

Jessup Neck..................................................................... 142 

Hog Neck.,. ............... · ..................................................... : 142 

Cedar Point .................................... ~................................ 142 

Hog Creek Point................................................................. 142 

Montauk peninsula.............................................................. 143 

Robins Island .................... : .... · .......... ·... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145 

Shelter Island................................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145 

Gardiners Island ................... · ................................ ·............... 146 

Plum Island ...................................................... ;............... 146 

Fishers Island ............................... ~ ................................. ·... 147 

Deposits penetrated by wells...................................................... 147 

Age................................................................................. 149 

Hempstead gravel member ............................................................. ·.· 150 

Name................................................................................. 150 

Character ...................................... · .... : . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150 

Source of material ................................. · ......... , .. :...................... 151 

Relations to older deposits ............................................... , . . . . . . . . . . . . . 151. 

Structure .......................................................... ·. . . . . . . . . . . . . . . . . . 151 

Distribution.......................................................................... 151 

Relation of Hempstead gravel member and Montauk till member.................... 151 

West of Little Neck Bay......................................................... 152 

Great and Manhasset necks, North Hempstead..................................... 152 

Oyster Bay ................................................ ·...................... 152 

Lloyd Neck. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152 

Little Neck, Hu!].tington.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . 153 

Smithtown Bay region .............. ·.............................................. 153 

Port Jefferson to Wading River. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153 

Friars Head ....................... ·.............................................. 153 

Roanoke Landing and Jacob HilL................................................. 154 

Oregon Hills and vicinity........................................................ 154 

Rocky Point.................................................................... .154 

Riverhead to Sag Harbor......................................................... 154 

Hog Creek Point ........................................... ·_ . . . . . . . . . . . . . . . . . . . . . '155 

Montauk peninsula. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155 

Adjacent islands. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156 

Deposits penetrated by wells.......... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156 

Age ........................................ ·......................................... 157 

Vineyard formation.:... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157 

Wisconsin drift. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158 

The till sheet. ..................................... ·. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158 

Character. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158 

Source of material ............. ·. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159 

Relations and stmcture ............................................................... · 160 

Distribution.......................................................................... 160 

Qreater New York.,............................................................. 160 

Little Neck Bay to Oyster Bay.................................................... 161 

Oyster Bay to Port Jefferson....................................................... 161 

Cold Spring Harbor region ..... ~- ........ :........................................ 161 

· Dix Hills ................................................................. · . . . . . . . 162 

Smithtown "driftless area"...... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162 

Middle Island region ........................................ ·. . . . . . . . . . . . . . . . . . . . . . 162 

Peconic River region ............................ ·. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162 

Riverhead to Orient Point ........................................................ ·. 162 

Adjacent islands and the South Fluke ....................................... ·...... 162 

South of the Ronkonkoma moraine...... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • 163 
X CONTENTS. 

Stratigraphic geology-Continued. 

Quaternary system-Continued .. 

Pleistocene series-Continued. 

Wisconsin drift-Continued. 

Ronkonkoma moraine .................................................................... . 

Name ............................................. : ................................. . 

Character of material ................................ _ ......... _____ ._._._ .. · ......... . 

Source of material ............... ___ . __ . ________ .... _ ... _ .... _ ... _ .. _ ............... _ 

Relations to older deposits.· ........ _ .... _ ... ___ . _ ......... _ . _____ ........... _ ... _ ... . 

Distribution ..... _ .. __ ... _. __ .. _. _. _. _. _ ... ___ . _ .. __ ... _. _ .. _ ...... _ ..... __ ........ . 

Outwash from ice along Ronkonkoma moraine ............................................ _ 

Occurrence ........................ _ . _ ........................... _ . __ ~ __ . ___________ . _ 

Character of materiaL ................................ : ........ _ ... _. _____ . ___ ....... . Source of material ......... ______________________ . __ ... __________ . _ . _________ . __ . __ .. 

Relations to older qeposits ................ _______ . _ . _ .. ______________ .. _ ... _________ _ 

Distribution ................................... _____ . ___ ........ __ . ____ .... __ .. ___ . _. _ 

Harbor Hill moraine ........................................... ____ . ________ . _ .. _ ... ____ . 

Name ..................... _______________ :'---------------------------------···-------

Character.and source of mater~aL ..... _. __ .. __ . _ .. __ . _________________ . _. _ ... __ . ____ . _ 

Relations to older deposits ........................ _ .... __ . _____ . _ ... ____ ..... ___ . __ .. 

Distribution ............................................................. ____ .·. _____ .. 

Outwash from ice along Harbor Hill moraine ................................. _ . __ .. ____ .. . 

General characteristics ........................... ·- ....................... ~ ____ .. __ .. _ 

Distribution ................... _. _ ..... _ .. _ .. __ . __ . ___ . _. _________ .. _. __ . _____ . ____ . 

Narrows to Jamaica ............................................... ___ . __ . _ .. ____ _ 

Roslyn-Hempstead region .............................. · ................... __ .... . 

Wheatley-Cold Spring region ......................................... ___ .. ______ .. 

Huntington-Babylon region ........ _ ... _________ ._. ___ ._. _________________ :_._._ .. 

Smithtown region .................... :_ ............ _ .................. _. ___ . __ ._. 

Port Jefferson region .......................................... _______ . __ . _ ... _ . _ 

Rocky Point and Riverhead area ................ _._ .. ________________ · __ . ______ ._. · 

North Fluke .................................. __ ._ .. ___ ._ ... ____ . ___ .. ___ ._ .. _._ 

Outwash channels .......... _ ..... _ . _ .............. __ . _________ ... __ . ____ ... __ . _ . __ . _ 

Roslyn channeL .......................................... _ .. _____ . _ .. _____ . _ . _ .. 

Melville channels ................................................... __ .. __ . ___ ... _ 

Centerport-Babylon channeL ............ _ ....................... ______ ... ___ ... _ 

Connetquot channeL .................................... _ ... ________ . _ . ________ . _ 

Carmans River channeL ................................................ __ .. _._._ 

Retreatal deposits ................. _ ....................................... _ . : _____ .... _ . _ Recent series ................. _ ........ __________ ._. ________ ._. _______________________ . _____ . ___ _ 

Extent ..................................................................................... _ 

Stream deposits ...................................... · .................................. _ ... . 

. Deposits in stream channels ............................ _________ . ______ .. _____ ... _ .. ____ .. 

Alluvial fans-........................................................................ _._._ 

Deltas ........................................... '_ ................................... __ . 

Marine deposits .............. -................................ ___________ ·- ____ ...... _ ........ _ 

Beaches and spits ..................................... ______ . __ ...... _ . _ .. ___ . ___ .. _ .... _ 

Connecting beaches ..................................................................... _ 

Small spits and hooks ................................... _________ ._ ... _____ . __ .. ___ ... ___ _ 

Magnetic and garnetiferous sands ................ : ___ ............................ __ .. _ . ____ _ 

Wind deposits ................................................ __ . _______ ... _. _____ ..... ______ _ 

Character and general distribution .......... _ ............ __ .. _ ..... ________ ....... _. __ .. __ _ 

Dunes at N apeague Beach ............................................. _· ............. ____ _ 

Dunes at Easthampton ................................ __ ._.~._. __ .. _ .... _.: _____ ·_ .. _____ _ 

Dunes of the great south beaches ......... : .......... : ................ , .................. . 

Dunes at Shinnecock Hills ............................... _ . ___ . _______ . _ . ___ ....... ________ . 

Dunes of the north coast .............................. ~ ................ _· ................. . 

Dunes in the interior of the island ................................ __ . _ ... _ . _____ .... _____ _ 

Marsh deposits .............................................................. -- .......... ______ _ 

Fresh marshes ................................................................. ____ . _____ _ 

Marshes of the south shore ................................................... _ ........ . 

Marshes in the valleys of the south side ................. _ ... __ . _ . ____ ....... __________ _ 

Marshes near artificial ponds .......................................................... . 

Marshes in obstructed channels ........................ _ . __________ ~ _ ..... ____ . ______ _ 

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CONTENTS. 

Stratigraphic geology-Continued. 

Quaternary system-Continued. 

Recent series----:-Continued. 

Marsh deposits-Continued. 

Fresh marshes-Continued. 

Marshes in kettles ............................................................. . 

Marshes behind beaches ............................................................ . 

Interdune marshes ................................................................... . 

Salt marshes ........................................................................... . 

Marshes of the south shore ........ · ....................... · ........................... . 

Marshes of the south-shore bays ....... ~ ..... · ......................................... . 

Marshes of the north-shore reentrants .................................................. . 

Summary of geologic feature.s, by localities ............................................. · .................. . 

. Geologic history ................................................................. _ .................... __ .. 

Pre-Cretaceous events ..................................................................... ·_ .......... . 

Cretaceous events ................................................... .' ............................... . 

Tertiary events ..................................................... -.- .............................. . 

Eocene epoch ................................................................................ _ ... . 

Miocene epoch ................................................................................... . 

Early Pliocene epoch ....................................... ~ .......... _ ................ _ .. _ .... _ 

Late PliO'cene (?)epoch (Lafayette formation) ................................................... .. 

Post-Lafayette erosion .................................................................. _ ....... . 

Quaternary events ............................................................................ _. ...... . 

Pleistocene epoch ........................................................ _ ..... _ ... _ ............. . 

Mannetto glacial stage ....... ' ................................. : . ...................... _ .. _ .. . 

Post-Mannetto interglacial stage .............................................................. . 

J ameco glacial stage ...... · ................................ _ ..... _ ......... _ ............... _ .. 

Gardiners interglacial stage ....................................... _ ..................... __ ... . 

~~~~at:.~:~s~~~~7:i :::::: : : : : : ~-: : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 

Herod glacial substage ................................................................. _ .. 

Montauk glacial substage ..... · ........................................................ _ .. . 

First advance of the ice ............................................................. . 

Position of ice margin .................................... · ....................... . 

Erosion by the Montauk ice sheet ................................................. . 

Accumulation of the earlier deposits of the Montauk till member .................. . 

Folding during Montauk substage .................................................... . 

Extent ................ · ............................................... · .......... _ 

Anticlinal nature of the fluke ridges .............................................. . 

Possible causes of the flexures .................................................... . 

Minor warpings ................................................................. . 

Open and closed folds ................................ ~ ......................... . 

First recession of Montauk ice ....................................................... . 

Read vance of the Montauk ice ...................................................... .. 

Hempstead gla-cial substage ........................................................ _ .... . 

Final retreat of the Montauk ice ..................... : ................................ . 

Vineyard interglacial stage .............................. _ ............................... _ .... . 

Erosion .......................... _ ...................................... ________ . _· . ____ . _ 

Deposition ....................................... _ ................. _ ......... _ .. _ ... _ .. _. 

Wisconsin glacial stage ........................................ · ....... _ ....................... . 

First advance of the ice .............. · ................................................... . 

First recession of the ice ............................................... _ .. __ ......... _ .. . 

Read vance of the glacier .............................................................. _. 

Final retreat of the ice .................................................................. . 

Recent epoch ............................................ · ........................................ . 

\Vork of wind and water ................................................... , .......... _ ....... . 

Subsidence of the land.· .............................................. _ .. _ ........ _ ............ . 

Evidence ..... • ......................................................................... . 

Conclusions ............... · ...... : ................................ _ ...................... _ 

Lengths of Pleistoce1ie and Recent stages and substages ....................................... . 

Summary of Pleistocene and Recent orogenic movements ..................................... . 

Mannetto depression .............. , .. ·_ ........ '. ......................................... . 

· Post-Mannetto uplift ................. · ...................................................... . 

Jameco depression .................................................. ~- ....... ~ .......... . 

XI 

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XII CONTENTS. 

Geologic history-Continued. . 

Quaternary events-Continued. 

Recent epoch-Continued. , 

Summary of Pleistocene and Recent orogenic movements-Continued. Page. 

Gardiners uplift .......... _ ......... _ ... _._ ... __ ............................ _ _ _ _ _ _ _ _ _ _ _ _ 219 

Jacob depression ..... _ .................................................................. _ 219 

· Herod and Montauk depression ....... _ ................. _._._._._._ ... _ ........ _._ .... ____ 219 

Hempstead uplift .................................. : .. _ ..... _·_ ............... ___ ._ ..... _ 219 

Vineyard uplift. ....................... _._ .............. _ ........................... _____ 219 

Wisconsin depression .................... : .................. , ................ _ ... _ .... _ . _ 219 

Recent movements ........ _ .................... -......... : ......... _ ................ _ . . . 219 

Correlations of the Lon'g Island Pleistocene formations_ ....... _ ..... _ .. ___ ...................... _ ......... _ 219 

Probable extension of the formations along the New England coast ...... __ ... _ ...... _._ .... __ .:. _____ ._._·_ 219 

Jl.{annetto gravel ....•........ _ . _ ... _ ..... _ . _ ....................................... _ ........... _ _ 219 

Jameco graveL ........ _ ... -.......................... _ .......... _ ........................... _.__ 220 

Gardiners clay .. __ .. __ ............................. _ ........ _ ......................... _ . _ . _ .. _ . . . 220 

Jacob sand .............................. -.......... -.- ........... -... -... -.................. _.__ 220 

Manhasset formation ....•................................. _ . _ ............ _ .... _ . _ .... ____ . _ .. _ .. _ 220 

Herod gravel member ....................... _ ....... · ...................... _ ...... ____ .... _.__ 220 

Montauk till member ..................................... : ...................... _ .. __ .. _ . _ . . 221 

Hempstead gravel member ........................ _ ..... _ .... : ........... ,. _____ . ____ . _ _ _ _ _ _ _ 221 

Vineyard erosion intervaL ...................... _ ......... _ ..... _ ............... _._ ..... _._.______ 221 

'\Visconsin drift ............•...... -........................................ _ .. _ ...... _ _ _ _ _ _ _ _ _ _ _ _ 222 

Correlation with the New Jersey nonglacial formations ................ , ...... _._. __ .. __ . __ .______________ 222 

General conditions .... : . ...................... _· .......................... _ .............. _ ..... _ . _ . . . 222 

Correlations ....... _ .............................. : ........... -............ _ .......... _ ..... ___ . . . . 222 

Lower Cape May terrace ....................................... _ ..... : ... _ ........ _ ...... _ . . . 222 

Higher Cape May terrace .......................................................... _ ......... _ 222 

Intermediate stream deposits ........................ -............... _ ...... _ ........ _ .... _. . . . 223 

Pemauken formation ............. -..................................... __ ........ _ .... ___ . _ _ 223 

Bridgeton formation ................... __ .......................... _ ............... _ ... _ .... _. 223 

Index ......... _ .... ~ ................... -............ -. -. -. -.. -. -. -........ -. ~ . -. . . . . . . . . . . . . . . . . . . . . . . . 225 

ILLUSTRATIONS. 

Page. 

PLATE L Geologic map of Long Island, N. Y ..................................................... _. __ In pocket. 

IJ- Topographic map of Long Island, N. Y. _ .................................... _ .. _ ...... _. __ . _ In pocket. 

IlL Topographic map of Mannetto Hills region ..... _ ........... -.- ......... _ .......... _. __ . __ ..... ___ . 28 

IV. Topographic map of Great and Manhasset necks ....... _ ... _ ..... _ .... __ .. ___ . ____ .... _ .... __ .____ 30 

V. A, Outwash plain from ice along Harbor Hill moraine; B, Bowldery part of Harbor Hill moraine near 

·Creedmoor .............. _ ........................ -.......... _ ...................... _ .... ____ . . 32 

VL Topographic features of Long Island: A, Upper and lower Manhasset plateaus near Hempstead Harbor; 

B, Till moraine near Ja,maica; C, Sand and gravel moraine southwest of Riverhead; D, Mannetto,' 

Manhasset, morainal, and outwash topography near ·wheatley ...... _ ..................... _. _____ .. 32 

VII. Topographic features of .Long Island: A, Simple m.orainal ridge near Hauppauge; B, Depressed moraine and outwash near Port Jefferson; C, Parallel "fosse" channels on Montauk peninsula ........ _ 34 

VIII: Pseudomoraine (dunes) near Friars Head: A, Distant view; B, Section .... _ ........ _ ... _. ___ ._ .. _._ 34 

IX. Topographic features of Long Island: A, Kettle valley and kettle chain near Bridgehampton; B, 

Kettle valley near Fresh Pond Landing; C, Kettle valleys, kettle chains, and pre-Wisconsin 

drainage lines northwest of Riverhead ........ _ .......... -............................ _ ... __ . . . . 42 

X. Topographic features near Smithtown and Lake Ronkonkoma ......... ~ ...................... _____ . 46 

XL Topographic features ,of Long Island: A, Pre-Wisconsin erosion scarp near Creedmoor; B, Recent 

erosion scarp of ·north coast; C, Branching kettle valley with reversed drainage near Mattituck; 

D, Slightly modified and overridden scarps near Brooklyn ... -~ ..................... _. ______ ._.. 52 

XII. General view of great landslip area at Broken Ground, northeast of Northport .......... _ ...... ·..... 54 

XIII. Broken Ground landslip area, northeast oj Northport: A, Inner scarp and tilted block; B, Upturned 

Cretaceous clays at base of landslip mass........................................................ 55 
ILLUSTRATIONS. 

PLATE XIV. A, Main scarp at Broken Ground landslip area, northeast of Northport; B, Cretaceous deposits 

on Lloyd Neck ................................... · ......................................... . 

XV. ~lap showing position of bedrock in western Long Is_land ...................................... . 

XVI. Map showing the elevation of the Cretaceous surface in western Long Island ................... . 

XVII. A, Structure of Cretaceous clays on Little Neck, Huntington; B, Large decomposed erratic 

bowlder in Mannetto gravel. ............................................................... . 

XVIII. A, Upturned Gardiners clay and Jacob sand on east coast of Gardiners Island; B, Overtlirned fold of 

Jacob sand lying on Herod gravel member of Manhasset formation, east coast of Gardiners Island. 

XIX. A, Folded beds of Manhasset formation near Tom Point, Port Washington; B, Banded Montauk. 

till member of :L\1an hasset formation near Friars Head ...................................... . 

XX. Topographic features near Middle Island ...................................................... . 

XXI. A, Outwash topography near Southampton; B, Manhasset and outwash topography near Amagansett. 

XXII. A, Contact of \Visconsin till with Montauk till member at Lloyd Neck; B, Gravels (Montauk member 

of1-Ianhasset formation?) on Lloyd Neck ..................................................... . 

XXIII. A, Unconformable contact between Hempstead (?)gravel member of Manhasset formation and 

Cretaceous deposits on Little Neck, Huntington; B, Manhasset gravel folded by overriding ice. 

X:XIV. A, Typical bowlder beach on North Fluke; B, Banded Wisconsin till on old gravels (Mannetto?), Dix Hills ..................................................................... : .. . 

XXV. Hooked sand spit at entrance to Smithtown Harbor ........................................... . 

XXVI. A, Undermined peat on coast near Prospect Point, Manhasset Neck; B, Semidune surfac~ in 

interior of island near Selden ........................................... : ................. . 

XXVII. A, B, Mud cones marking orifices of springs in mud flats near Douglaston ................... ~ .. . 

FIGURE 1. index map of Long Island and southern New England ..................................... ·: .. . 

2. Map of the eastern United States, showing physiographic provinces ............................. . 

3. Manhasset plateau and the superimposed moraine as seen from Long Island Sound ............... . 

4. North-south profile of Long Island ................... ~ ........................................ . 

5. Relations of Cretaceous, Mannetto, Manhasset, and present north-shore scarps ................... . 

6. Relation between the original and the present cross section of north-shore valleys ................. . 

7. Sketch showing location.of the upper and lower Manhasset plateaus from Douglaston to Oyster Bay .. 

8. Sketch showing location of the upper and lower Manhass.et plateaus in the Lloyd and Eaton necks 

region .................................................................................... . 

9. Section showing relations of Manhasset plateaus and deposits along the north shore in western Long 

10. 

11. 

Island .................................................................................... . 

Section showing mode of formation and profiles of morainal cones ............................... . 

Profiles of morainal cones ....................................... ~ ............................ . 

12. Section showing relation between depressed moraine and outwash ............ ~ .............. ~ .. 

13. Hypothetical drainage system i11'loose gravels before being covered by ice ....................... . 

14. Hypothetical condition of drainage system of figure 13, after being overridden by glacial ice ....... . 

15. Profile of a compound outwash fan of successive-plain type ..................... :_ ............... . 

16. Normal profile of till moraine ................................................................ . 

17. Normal profile of stratified moraine ........................................................... . 

18. Section illustrating the formation of a kettle from a buried ice mass ......... · .................... . 

19. Section illustrating the formation of a kettle from a projecting ice mass ........................... . 

20. Section illustrating the relation between the slopes of kettle sides and the shape of melted iGe mass .. 

21. Section illustrating the relation between the slopes of kettle sides and the shape of melted ice mass .. 

22. Section illustrating the formation of kettle terraces by the melting of ice masses of especial Ehapes .• 

23. Section illustrating the formation of depositio~al terraces between ice mass and kettle wall ........ . 

24. Profile of terraced kettle near Lake Grove ................................................... . 

25. Profile of kettle with o~1twash rim ....................... ' ......... · ....................... · ... . 

26. l{ettle rims ............ · .................................................................... . 

27. Outwash rim adjoining kettle 2 miles northwest of Southampton ...... · ........................ . 

28. Pre-Wisconsin drainage system in Manhasset formation ........................................ . 

29. Kettle valley system remaining after the melting of Wisconsin ice massea ....................... . 

30. Cross section along the line A-B of figure 28, showing residual ice masses partly buried by outwa!'!h .. 

31. Cross section along the line A-B of figure 29, after melting of ice masses ......................... . 

32. Profile along the course of the kettle valleys of figure 29 ........................................ . 

33. Profile of kettle plain ........... · .................. ~ .. .' .................. .' ................... . 

34. Profile showing a channel between kettles ................... : ......................... · ...... . 

35. Profile showing relation of inner and outer fosses to moraine ................................... . 

36. Profile showing fosse at inner base of moraine near Duck Po:Qd Point ............................ . 

37. Profile of inner-fosse channels west of Fort Pond Bay, Montauk peninsula ........................ . 

38. Sections of terraced channell,eaqing westward from Lake Ronkonkoma ......................... . 

xm 

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XIV ILLUSTRATIONS. 

FIGURE 39. Forms of outwash valleys ................................................................... . 

40. Profile showing relative steepness of east and west banks of Long Island valleys ................. . 

41. Section illustra~ing formation of amphitheaters by spring sapping ................................ . 

42. Plan of hopper or amphitheater at an early stage .............................................. . 

43. Plan of transitional form between a hopper and a normal drainage system ..... ·.· ... _._ ........... . 

44. Plan showing character of notching in bluffs of the northern coast in eastern Long Isla~d ......... . 

45. Section illustrating the relation of height of hanging valleys to stage of erosion of bluffs .......... . 

46. Se.ction illustrating the notching of hanging valleys ............................................. . 

47. Section illustrating the obstruction of valleys by landslides ..................................... . 

48. Section of refilled ravine of the north coast .................................................... . 

49. Sectio_n showing the nature of displacement in the larger landslides.· ............................ . 

50. Map showing Cretaceous structure and location of submarine channels of Long Island Sound ...... . 

51. Map of the submarine channel and. canyon of Hudson River ................................... . 

52. Cross section showing relations of the broader valleys and sharp canyon of the submarine Hudson 

channels ............................... ·.· ................................................. . 

53. Section showing relations of the submarine Hudson channels and their fillings ................... . 

54. _Sections from Hudson River to Long Island .................................................... . 

!)5. Columnar section of the Cretaceous formations of Long Island .................................. . 

56. Map showing known distribution of Cretaceous formations on western Long Island ............... . 

57. Section showing general relations of deposits in the Mannetto Hills region ........................ . 

58. Section from point near Ridgeway, Brooklyn, to Valley Stream ................................. . 

59. Section 2! miles southwest of Montauk Light ................................................... . 

60. Section near the middle of the northeast shore of Gardiners Island .............................. . 

61. Sections near Browns Point ....... : .......................................................... . 

62. Section from Wards Island to Barnum-Island ................................................... ,. 

63. Section near Eastern Plain Point, Gardiners Island ............................................. . 

64. Section near Jacob Hill, showing overturned fold of Gardiners clay .............................. . 

65. Section at Rocky Point, west of Cold Spring Harbor ............................................. . 

66. Section north of West Beach, Eato~_Neck ........................................................ . 

67. Section half a mile west of Rocky Point Landing, northeast of Miller Place ...................... . 

68. Section near Rocky Point Landing, northeast of Miller Place .................................... . 

69. Section west of Hallock Landing ............................................................. . 

70.· Section a quarter of a mile east of Roanoke Landing ............. ~ .............................. . 

· 71. Section three-quarters of a mile east of Roanoke Landing .............. · ... · ...................... . 

72. Section near Jacob Hill ...................................................................... . 

73. Section at Brown Hills, near Orient ........................................... ~ .............. . 

74. Section on east side of Robins Island ..................................................... · .... . 

·75. Section on east side of Robins Island ......................................................... . 

76.' Section half a mile west of False Point, Montauk ......................................... ~ ..... . 

77. Section near Cherry Hill Point, Gardiners Island .............................................. . 

78. Section a quarter of a mile east of northwest end of bluffs on northeast coast of Gardiners Island ... . 

79. Section three-quarters of a mile east of northwest end of bluffs on northeast coast of Gardiners Island. 

80. Section near Whale Hill, Gardiners Island .................................................... . 

81. Section near south end of Bostwick Bay, Gardiners Island ..................................... . 

82. Section on south side of Plum Island .................................................. : ...... . 

83. Index map to localities on Fishers Island .................... : . . · .............................. . 

84.· North-south section at Clay Point, Fishers Island ................................ · .............. . 

85. Generalized section of Fishers Island ......................................................... . 

86. Northeast-southwest section along Isabella Beach, Fishers Island ............................... . 

87. Section 1! miles southwest of Montauk Light .................................................. . 

88. Section north of Weeks Point, Hempstead Harbor ................................. · ............ . 

8!). Section a quarter of a mile west of Hallock Landing ..... .' ...................................... . 

90. Section near Woodville Landing ............................................................. . 

91. Section at landing west of Jacob Point ........................................................ . 

92. Section near Jacob Hill ....................................................................... . 

93. Section at Jac9b HilL ................ · .................................................... . 

94. Section at Brown Hills, near Orient. ......................................................... . 

95. Section at Brown Hills, near Orient .......................................................... . 

96. Section at Brown Hills, near Orient. ..... ~ .................................................... . 

97. Section at Brown Hills, near Orient. .................................... ' ..................... . 

98. Section on west side of Robins Island .................................. , ...................... . 

99. Section half a. mile north of Cherry Hill Point, Gardiners Island ............................... . 

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ILLUSTRATIONS. 

FIGURE 100. Section near west end of bluffs on northeast shore of Gardiners Island .......................... . 

101. Section half a mile east of west- end of bluffs on northeast coast of Gardiners Island ....... : ..... . 

102. Section half a mile w.est of landing, Plum Island ............................... ~ ............. . 

103. Section along middle of south side of Plum Island .... : ....... · .................... ~ ............ . 

104. Section east of Fort Terry, south side of Plum Island ......................................... . 

105. Section east of Fort Terry, south side of Plum Islancl. ................ : ....................... . 

106. Bluff section at Isabella Beach, Fishers Island ............................................... . 

107. Cross sections showing structure of Long Island ................ ~ .......................... · ..... . 

108. Diagram of vertical pseudo bedding in Herod gravel member ................................... . 

109. Section near Quince Tree Landing, Montauk ................................................. . 

110. Section on the coast north of Fort Salonga .... · ............................................... . 

111. Section half a mile east of Woodhull Landing ................................................ .. 

112. Section a quarter of a mile west of Hallock Landing ............ ~ .... ·.· ...... : ................ .. 

113. Section west of Herod Point ................................................................. . 

114. Section near Paine Landing ................................................................. . 

115. Section near Friars Head ............. ~ ........... : ......................................... . 

116. Section 1 mile southwest of Duck Pond Point ............................ ~ ................... . 

117. Section northwest of Shinnecock Canal. ..................................................... . 

118. Section northwest of Shinnecock Canal ...................................................... . 

119. Section east of Cedar Point, northeast of Sag Harbor .......................................... . 

120. Section between C€>dar Point and Sammys Beach, northeast of Sag Harbor ...................... . 

121. Section east of Cedar Point, northeast of Sag Harbor .......................................... . 

122. Section east of Cedar Point, northeast of Sag Harbor ............................................. . 

123. Section west of Sammys Beach ................................................................ . 

124. Section near Culloden Point, Montauk ....................................................... . 

125. Section 1 mile north of Quince Tree Landing, Montauk ....................................... . 

126. Section 1! miles north of Quince Tree Lancling, Montauk ................................ · ..... . 

127. Section on west side of Robins Island ................................ ~ ...................... . 

128. Section on east side-of Robins Island ................................. · ...................... ~. 

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160. 

Section half a mile south of west end of bluff on northeast coast of Gardiners Island ............. . 

Section near point at south end of Tobacco Lot Bay .......................................... . 

Section near lightliouse at west end of Plum Island ........................................... . 

Details of faulting in Herod gravel member near west end of bluffs on south side of Plum Island .. 

East-west section in clay pit on Fishers Island ...................... .' ........................ . 

Section through hill three-quarters of a mile northeast of cast end of Isabella Beach, Fishers Island. 

Section parallel with beach at headland three-quarters of a mile northeast of east end of Isabella 

Beach, Fishers Island ........ ~ ........................................................... . 

Section one-third of a mile east of College Point .............................................. . 

Section at Barker Point~ }.~Janhasset N ack .................................................... . 

Section east of Lloyd Point, Lloyd Neck ...................................................... . 

Section midway between Nissequogue River and Stony Brook Harbor ......................... . 

Section showing details of the Montauk-Herod contact at the locality shown in figure 130 ........ . 

Itoaclsicle sectionn~ar Stony Brook station ..... · .............................................. . 

Section of pinnacle of Montauk till member near Friars Head .................................. . 

Section near Friars Head ................................................................... . 

Columnar section east of Roanoke Landing. : . ................................................. . 

Section half a mile east of Luce Landing .............................. _._ .................... : .. 

Section three-quarters of a mile east of Luce Landing .......................................... . 

~=~!~~~~ ~~~r~g~~~I~!~~~- P;i;;t·. -. ~: ~ .- _-_-_-_ -. ~::::::: ~::::::::::::::::::::::::::::::::::::::::::: ~ Section a quarter of a mile south of Inlet Point. ............................................... . 

Section 2 miles northwest of Shinnecock Canal. ............................................... . 

Section on west side of Hog Neck, northwest of Sag Harbor ................................... . 

Section on west side of Hog Neck, northwest of Sag Harbor ......... : ......... ~ ..... : ......... . 

Section near Hog Creek Point, on South Fluke .................................................. . 

Section near Hog Creek Point, on South Fluke .................................. · .......... : ... . 

Section 1 mile west of Rocky Point, Montauk ............................. · ................... . 

Section 1 mile west of Rocky Point, Montauk .................................. ~ ............. . 

Section half a mile south of Culloden Point, Montauk .................................... _ .... . 

Section east of Montauk Light ............................................................. . 

Section southeast of:Montauk Light................. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ........... .. 

Section It miles southwest of Montauk Light ........................................ : ........ . 

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XVI . ILLUSTRATIONS. 

Page. 

FIGURE 161. Section 11 miles southwest of Montauk Light ................................................. . 144 

162. Section 2 miles southwest of Montauk Light ................................................... . l44 

163. Section on south side of Montauk peninsula between N apeague and Hither Plain life-saving stations. 145 

164. Section on south side of Montauk peninsula betweenNapeague and Hither Plainlife-saving stations. 145 

165. Section on east side of Robins Island ... , ..................................................... . 145 

166. Section on east side of Robins Island. ~ ...................................................... . 145 

167. Section at south end of Bostwick Bay, Gardiners Island ....................................... . 146 

168~ Section near north end of bluffs on northeast shore of Gardin'ers Island ...................... . 146 

169. Section east of Whale Hill ................................................................. . 146 

170. Section near west end of bluffs on south side of Plum Island .................... ~ .............. . 146 

171. Section east of Fort Terry, Plum Island .............................. · ......................... ' 146 

172. Section east of Fort Terry, Plum Island ...... · ................................................ . 147 

173. Artificial section near the steamboat landing on west side of West Harbor, Fishers Island ...... . 147 

174. Section east of Montauk Light .............................................................. . 151 

175. Section 1 mile northwest of East Fort Point, Lloyd Neck ...................................... . 152 

"176. Section northwest of East Fort Point, Lloyd Neck ........................................ ·· ..... . 152 

177. Section.in clay pit near end of Little Neck, opposite Northport .................... · .......... . 153 

178. Section near Friars Head ................................................................... . 153 

179. Columnar section between Friars Head and Roanoke Landing ................................ . 153 

180. Columnar section near Roanoke Landing ............................................. _· ....... . 153 

181. Section west of Jacob HilL ...................................................... , .......... . 154 

182. Section west of Jacob Hill ............ · ................................................. : .... . 154 

183·. Section northwest of Shinnecock CanaL ....... ·.· ............................................ . 154 

184. Section on Jessup Neck, west of Sag Harbor ........................................ : ........ . 154 

185. Section on Jessup Neck, west of Sag Harbor .................................................. . 155 

186. Section near. Fireplace, South F_luke ......................................................... . 

187. Section near Culloden Point, Mont~uk ........ : .............................................• 

155 

155 

188. Section 1 mile west of False Point, Montauk ................................................. . 155 

189. Section south of Montauk Light. .................... , .......................................• 155 

190. Section 2~ miles east of Ditch Plain, Montauk ...............................................• 156 

191. Section half a mile east of Ditch Plain, Montauk ............................................. . 156 

192. Section westof Ditch Plain, M;ontauk ................................. ·_ ...................... . 156 

193. Section on west side of Robins Island ........................................................• 156 

194. Section on west side of Robins Island ....................................... : ................• 157 

· 195. Section showing till ridge at head of valleys openinG to \he north ...... · .......................• 161 

· 196. Profile of Carmans River outwash channel near Yaphank .................... : ................ . 

197. Kettle rim of till near highway between Mattituck and Cutchogue ....... · ...................... . 

198. Diagram illustrating compression of beds through rearrangement of grains ....................... . 

168 

174 ""' J 

202 1 

199. Diagram showing supposed compression of peds under ice load in the Long Island region ....... . 204 

200. Diagram showing supposed influence of Cretaceous masses in controlling the compression of the 

Pleistocene deposits under ice load ....................................................... . 204 

201. Profile of imperfect 40-foot terrace east of Fort Pond, Montauk ................................ . 

202. Section at top of bluffs between Woodhull and Rocky Point la~dings . __ ...................... . 

208 

210 

· 203. Sketch map showing relative positions of 1ce during the Ronkonkoma and Harbor Hill substages 

·of the Wisconsin stage ......................................................... : .......... . 210 

- 204. Position of land with reference to present sea level in the Pleistocene stages and substage5 ........ . 218 

- 205. Diagram showing the relations of the higher and lower Cape May terraces to the so-ca:lled "Trenton 

gravel" along Delaware River in New Jersey ..............................................• 222 

INSERT. 

Page. 

Approximate correlations of the Pleistocene formations of ;Long Island with deposits of other ar~as............ 220 
• 

' 

THE GEOLOGY OF LONG ISLAND, NEW YORK. 

By MYRON L. FULLER. 

INTRODUCTION. 

'\ 

Location.-Long Island, New York, is the largest island adjoining the coast of the United 

States proper. It is 118 miles long, extending from the Narrows at the entrance of New York 

Harbor (longitude 74° 2' W.) to a point nearly due south of the eastern boundary of Connecticut 

·(about 71° 50' W.). Its maximum width is about 20 miles. The island is included in the 

State of New York, but only a few miles of its shore line is adjacent to the mainland portion 

of that State, more than seven-eighths of its total length lying off the Connecticut shore (fig. 1). 

Geologic relations.-In its general geologic relations Long Island belongs to the inner part 

of the Atlantic Coastal Plain (fig. 2), the line between the deposits of this plain and the metamorphic rocks upon and against which the sediments were laid down crossing the extreme west 

end of the island near Long Island City. The basal or fundamental deposits ·are of Cretaceous 

age and correspond to beds of similar age in New Jersey and the region farther south. · They 

appear at a considerable number of 

points in the western half of. the 

island but in the eastern part are 

nowhere seen at the surface. No 

equivalen.ts of the Tertiary deposits 

of the mainland have been definitely 

recognized, although some loose 

sands possibly referable to the Tertiary period have been noted at one 

point. 

Only a part of the deposits of 

Nantucket 

~....._._..~....o ~---1.25.:_· __;,__5~_0 __ 7....~....__....Jl00Miles 

FIGURE I.-Index map of Long Island and southern New England. 

·the island are true coastal-plain deposits, the greater portion of both 

the surface and the underlying materials throughout the island being of 

Pleistocene age and representing the 

n1orainal and outwash accumulations associated with the continental 

glaciers (fig. 2). The two morainal 

ridges, which are among the most conspicuous features of this area and which together 

form "the backbone of the island," are the dhect continuation of the series of moraines of 

Wisconsin age which are traceable almost continuously from the Rocky Mountains to New 

Jersey and thence through Long_ Island and the islands on the east as far as· Nantucket and 

Cape CocJ.; The various beds .making up the considerable thickness of Pleistocene accumulations beneath the ridges mentioned ·and above the Cretaceous formations likewise represent 

older drift sheets of the central U~ited States on the west ·and the Pleistocene formations of the 

·New England coast on the northeast .. 

Purpose of thi$ investigation.-The investigation of the geology of Long Islal)d was under-

-taken iri connection with ~ study of the underground waters of the island made by the United 

'1629°-14-2 1 
2 GEOLOGY OF LONG ISLAND. 

States Geological Surv~y in cooperation with the Commission on Additional Water Supply of 

New York City. During the progress of the work many new geologic facts were developed, 

some of which demanded extensive modifications of the views previously held as to the structure 

and geologic history of the island. In fact, a complete revision of the geology became necessary 

in order that the observations on the underground waters might be thoroughly understood. 

';I.'his geologic work was conducted in connection with the water investigation during 1903, most 

of the roads on the island being traversed and a very large number of well records collected. 

Geologic work was continued during several weeks in 1904 and again for a few days in 1905, to 

complete a study of bluff sections along the north shore and to estabpsh the correlation of the 

Long Island deposits with other Pleistocene deposits on the east and west. 

-------Limits of ice invasion 

FIGURE 2.-Map of the eastern u:O:ited ~tates showing physiographic provinces. 

Status of Pleistocene 

correlation.-From the able 

studies of Chamberlin, Cal- . 

vil1., Leverett, . and other 

United States and Canadian 

geologists, the Pleistocene 

deposits of the interior of 

North America have been 

differentiated and their ac-

. cumulation in a series of 

four or more successive 

glacial stages has been established. East of Ohio, 

however, because the last or 

Wisconsin invasion in many 

places· advanced farther 

than the earlier ice sheetsremoving, covering, or other-· 

wise obscuring their deposits-little has been done 

toward the differentiation 

and correlation of the drifts. 

A fringe of old, deeply 

weathered drift stretching 

across Pennsylvania and 

New Jersey, it is true, has 

long been recognized outside 

of the Wisconsin moraine 

and because of the weathered state of its materials 

bas been provisionally correlated with the Kansan or 

pre-Kansan. On Long Island Woodworth 1 recognized an earlier drift underlying the w·isconsin and separated from it by a distinct erosion 

unconformity, but beyond correlating it with the Columbia group of the Coastal Plain he made 

no attempt to assign it to a definite stage. On Block Island, Marthas Vineyard, Nantucket, and 

Cape Cod three glacial stages wjth intervening interglacial stages were recognized and a part of 

the Pleistocene history was decjphered.2 The invasions were designated the first, second, and 

1 Woodworth, J. B., Pleistocene geology of portions of Nassau County and Borough of Queens: Bull. New York State Mus. No.48, 1901, p. 624. 

2 Woodworth, J. B., Geology and geography of the clays, in Shaler, N. S., Woodworth, J. B., and Marbut, C. F., Glacial brick clays of Rhode 

Island and southeastern Massachusetts: Seventeenth Ann. Rept. U. S. Geol. Survey, pt.·l, 1896, pp. 975-988.. Shaler,~. S., Geology of the Cape 

Cod dist~ict: Eighteenth Ann. Rept. U. S. Geol. Survey, pt. 2, 1898, pp. 497-593.. · 
INTRODUCTION. 3 

third glacial stages, but no attempt was made to correlate them with the stages of the MiSsis~ 

sippi and Ohio valleys, which in fact had not then been fully worked out. No further attempt 

at differentiation or correlation was made until the problem was taken up by the writer and. 

his party in 1903, the question of ~quivalency of the eastern and central glacial deposits 

remaining one of the great unsolved problems of Pleistocene correlation in this country. 

Results of the work.-The results cf the work begun by the writer and assistants in 1903 

and continued in 1904 and 1905 have been the apparent establishment for the eastern region 

of all but one (the Iowan) of the five principal glacial stages recognized in central United States, 

the recognition of one or more substages, the discovery of criteria for differentiating the deposits 

of each stage, and the unraveling to a large extent of the c0mplicated history of the region. 

The evidences in rega1:d to the conditions and history of the principal glacial and interglacial 

stages on Long Island appear to be full:r as clear and conClusive as those in any single area 

of the earlier studied regions of the interior. 

Scope of this report.-The investigations along the New York and New England coasts 

have brought out the facts that the formations of the Pleistocene epoch were nowhere so well 

developed and the sequence of events is nowhere so clearly set forth as on Long Island, which 

in fact may be considered as affording the type section of the earlier glacial deposits. of the 

coastal zone. All stages except the Iowan are here represented. In the present report the 

Long Island section is 'discussed in considerable detail to supply a basis of ~omparison with 

sirqilar deposits elsewhere. This systematic discussion is followed by a short tabular summary 

of the geographic distribution of exposures, for the benefit of teachers and others interested in 

the physiography and geology of special localities, and by a chapter on corre~ation, in which 

the equivalency of the deposits of Long Island to glacial deposits elsewhere, especially to those 

of the New England coast, is considered. 

Field work and acknowledgments.-As already-stated, the geologic work was undertaken in 

connection with a cooperative investigation of the water resources of Long Island by the United 

States Geological Survey and. the New York Commission on Additional Water Supply in 1903 

and was continued independently of the commission in 1904 and 1905. The ground-water 

investigation included a careful collection of well records, of which about 1,500-many of them 

accompanied by samples of the materials penetrated-were procured. Other geologic work in 

1903 included traverses of practically every road outside of the portion of the island included 

in Greater New York and many visits to. special localities, mainly in connection with the studies 

of ground water. In 1904 a traverse was made of the north shore from Port Jefferson to Oriep.t 

Point and of the shores of Great and Little Peconic, Gardiners, and other smaller bays to Monta~k 

Point, during which the bluff sections were examined in great detail and ~ossils were collected 

at a number of points. Gardiners, Plum, and Fishers islands, portions of the Elizabeth Islands, 

l\1arthas Vineyard, Nantucket, and Cape Cod were also visited. In 1905 the investigations 

covered the bluffs along the north shore of Long Island from Port Jefferson westward, the coast 

of Rhode· Island from Watch I-Iill to Point Judith, and a number of previously unexamined 

points on the :Massachusetts coast as far north as Boston. . 

Valuable assistance in the work was rendered by a number of geologists. A. C. Veatch, 

to whom the investigation of the underground waters was assigned, rendered especially valuable 

service in the collection of well records and samples, and D. W. Johnson contributed largely to 

the success of the. areal investigations. Much paleontologic information in regard to the 

Cretaceous was furnished by Arthur I-Iollick, and Pleistocene fossils from several localities were 

identified by W. I-I. Dall. Aid in the geologic investigations on Long Island was also rendered 

by Isaiah Bowman and B. L. Johnson. In Rhode Island and Massachusetts F. G. Clapp assisted 

largely in establishing the Pleistocene correlations. For the interpretations and conclusions 

based on the bluff sections of Long Island and on the work done in the Elizabeth Islands and on 

l\1arthas Vineyard and Nantucket, as well as for most of those reached elsewhere in Jvfassachusetts, the writer is alone responsible. 
4 GEOLOGY OF LONG ISLAND. 

DEVELOPMENT OF THE GEOLOGIC LITERATURE ON LONG ISLANI). 

GENERAL TREND . 

. The earliest publication relating to_ the geology of Long Island of which the writer has 

information appeared about 1750. From that date until1800 little seems to have been written, 

but. between 1800 and 1827 a number of contributions on the geology of the island were published. 

In 1837 the preliminary results of the examination by theN ew York Geological Survey appeared, 

marking a new epoch in its literature, and a few years later the classic report on the first district 

was published. From this time until1878 a considerable number of papers, mainly descriptive, 

of Cretaceous and other fossils were issued, but little advance was made in the study of the 

younger deposits. Beginning with 1878 the drift received n1uch attention, and many papers 

of importance appeared, in which, however, the glacial epoch was regarded either as a unit or 

as two or more stages of indefinite age. The work of differentiation and cla~sification of the 

drifts, which began in 1901, opened the latest period in the literature of the island. 

From the preceding outline it is apparent that there-have been several phases or periods in 

the development of the study of the geology of the island as expressed by its literature, which 

for convenience may be described by terms indicating the characteristic trend of the papers 

published during the respective periods, as (1) alluvial phase, (2) diluvial phase, (3) early 

paleontologic phase, (4) early drift phase, and (5) later d~ift phase. 

LITERATURE FROM 1750 TO 1837 (ALLUVIAL PHASE). 

The period from 1750 to 1837 covers the beginning of the study of Long Island geology. 

In it the first geologic examinations of the island were made and the first classification and 

correlations of its deposits were attempted. It was not a period of detailed field examinations, 

most of the p1lblished observations being records of private travels, with occasional attempts 

at interpretation, but it was marked by the appearance of the first geologic map. 

To Dupont de Nemours is credited the first statement on the geology of the island that 

has been found. In a publication 1 appearing about 1750 he said that Long Island, although 

not a delta in form is one in reality, being formed by marine currents depositing the fluviatile 

alluvium brought down by Hudson, Passaic, Hackensack, and Raritan rivers. This early 

reference is much more in harmony with present views than those referring the island to the 

"primitive formation," which immediately followed it. We now know that the southern 

two-thirds of the island, if not a delta as postulated by De Nemours, is at least made up largely 

of confluvial deltas from glacial_streams. 

The next writer. of note dealing with Long Island appears to be Samuel L. :Mitchill. Writing in 1800,2 he referred the part of the island north of the "spine" (on the basis of the granitic 

bowlders which are abundant along the north coast) to the "primitive formation." His. paper 

gave a summary of the topography of the island and th~ erosion that was going on, stating 

that the island has been separated from the mainland by the encroachment of the salt water 

during the lapse of ages. He also discussed the marshes and beaches, the character, distribution, and immense size of the bowlders, and the occurrence of marine fossils in wells. Mitchill 

gave a further description or' the bowlders in a paper appearing in 1802 3 and expressed the 

belief that Plum, Gull, and Fisher islands on the north and Block Island on the south were once 

connected respectively with Orient and Montauk points. This is the first recognition of the 

essential continuity of the ridges later known as the inner and outer moraines. 

In 1809 appeared the first geologic map of the United States, accompanied by an explanatory paper by W·illiam Maclure.4 The map bears the note "By Samuel G. Lewis," but it appears 

to have been based on Maclure's observations, and is generally known as the Maclure map. 

~ On it the north half of the island is shown as "alluvial," a term then applied to all the unconsolidated beds of the Coastal Plain. This is also stated in the text. 

1 Quelques memoirs sur difierenssujets, quoted by W. W. Mather, Geology ofNe;v York, pt. 1, 1843, p. 150. 

2 A sketch of the mineralogical history of the State of New York: Med. Repository, vol. 1, 2d ed., 1800, pp. 279-303, 431-439; vol. 3, 1800, pp. 

325-335. 

a Mitchill, S. L., A sketch of the mineralogical history of the State of New York: Med. Repository, vol. 5, 1802, pp. 212-215. 

4 Observations on the geology of the United States: Trans. Am. Philos. Soc., vol. 6, 1809, J)P· 411-428. 
GEOLOGIC LITERATURE. 5 

Nlitchill, who a Jew years before had assigned the north side of the island to the "prinlitive formation," reversed his opinion in 1811 and stated that all of the Inaterial was alluvial 

except near "I-Iurlgate"' (Hell Gate), citing the occurrence of shells in deep wells as evidence 

of such origin. 1 . This appears to be the first reference to the fossiliferous silts now known as 

Gardiners clay. Seven years later Mitchill reiterated the conclusion as to the alluvia:! origin 

of the island and cited additional instances of buried shells. 2 In the same paper, in describing 

the northernmost ridge, he called attention to the superimposition of bowlders (Wisconsin) over 

the "marine deposits" (Manhassetformation). This may possibly be taken as the first subdi-· 

vision of the deposits of the island. 

In an account of his travels Tin1othy Dwight/ then president of Yale, noted the difference 

between the rounded character of the fragments over most of the island and their angularity 

west of Jamaica and at Montauk, this being the second distinction on Long Island of the deposits 

afterwards known as stratified drift and till. The hills at Shinnecock, which by 1nany later 

writers have been regarded as moraines, were described by Dwight as being at that time .bare 

hills of drifting sand. The island he regarded as having been formed as a bar by the Gulf 

Stream, which swept inward during the Deluge. Buried shells and logs of wood are described 

as occurring at several points. 

Writing in 1824;:-John Finch said 4 that no rivers are competent to deposit ·such masses 

of alluvial n1aterial as are found on Long Island, which he considered as being the northern 

extension of the Tertiary, the ridges, however, being referred to as "diluvial." The whole 

island was considered to be underlain by sand, gravel, and clays containing fossil shells 

(Venus, Ostrea, Murex, etc.) and tree trunks, and these beds were correlated with the clays at 

Amboy, N.J. . 

In 1827 S. G. Morton arranged and published certain notes of Lardner Vanuxem, 5 who 

recognized the "Secondary" (the equivalent of the present Cretaceous of the island) in addition 

to the Tertiary already recognized. 

LITERATURE FROM 1837 TO 1842 (DILUVIAL PHASE). 

The period from 1837 to 1842, though the shortest of the five into which the geologic literature of Long Island has been divided, is nevertheless among the most important, being 

marked by the publication of the results of the first systematic field exan1ination of the island_: 

that by the first Geological Survey of New York. It is characterized by detailed observations 

rather than by inferences, and in it the complexity of the geologic history of the island was 

for the first time distinctly recognized. Little further progress in solving the problems of· 

that history could be made as long as the hypothetical a diluvial process," the exact nature 

of which few pretended to comprehend fully, was appealed to as an explanation o~ the origin 

of the island. 

A report on the preliminary reconnaissance of the island by W. W. Mather, 6 geologist 

of the first district of New York, appeared in 1837 and included discussions of the economic 

geology, erosion features, bars and spits, landslides, dunes, erratic bowlders, clays, and the 

occurrences of fossils and lignite in deposits penetrated by wells. A year later 7 further descriptions of the geologic features .and processes were published. Mather's discussions of the 

extension of marshes, the occurrence of submerged tree stumps,· the encroachments of the 

sea, the formation of beaches, spits, and bars, the occurrence of garnet and magnetite sands, 

and the distribution of bowlders are of special interest, as is also his prediction as to the ultimate value of the peat deposits of the islal)d. 

1 Mitchill, S. L., An amendment proposed to the geological chart of the United States: Am. Mineralog. Jour., vol. I, 1814, pp. 129-133; Geology 

of Long Island: Idem, pp. 261-263. 

2 Mitchill, S. L., Observations on the geology of North America, appendix to Cuvier's Essay on the theory of the earth (tr. by Robt. Jameson), 

New York, 1818, pp. 379-382. • 

a Travels in New England and New York, vol. 3, 1822, pp. 283-336. 

• Geological essay on the Tertiary formations in America: Am. Jour. Sci., 1st ser., vol. 7, 1824, pp. 31-43. 

6 Geological observations on the Secondary, Tertiary, and Alluvial formations of the Atlantic coast of the United States of America: Jour. A cad. 

Nat. Sci. Philadelphia, vol. 4, pt. 1, 1827, pp. 59-71. 

o First Ann. Rept. New York Geol. Survey, 1837, pp. 61-95. 

7 Mather, W. W., Second Ann. Rept. New York Geol. Survey, 1838, pp. 121-184. 
6 GEOLOGY OF LONG ISLAND. 

Four years afterward appeared the classic report on the First district/ which contained a 

detailed discussion of Long Island. In this report, in addition to more complete discussions 

of. the processes and phenomena treated in the earlier reports, a classification of_ the deposits 

of the island was attempted and its origin was considered. The materials were divided into 

two systems-the Long Island syst~m, called "Upper Secondary" and made to include the 

Cretaceous and Tertiary formations, and the Quaternary system, comprising the Alluvial, 

Quaternary, and Drift divisions. The principal mass of the island, including the white clays, 

was held to be older than Tertiary, the lower beds being regarded as equivalents of the Cretaceous deposits of New Jersey, Delaware, and Maryland. The colored clays above the white 

clay, whicp_ were believed to underlie the whole island, were recognized as older than the surface 

drift and were referred to the Tertiary. This was the earliest recognition of a clay floor such as 

that described by -later geologists, although it is now known that two clays of widely different 

age and stratigraphic position were considered by Mather as one. After the deposition of the 

later clays (Gardiners clay) they were folded, as if by the lateral pressure of slides, after which 

they were denuded (Montauk ice erosion) before the deposition of the drift (Wisconsin) unconformably on their surfaces. 2 In the ''Drift division" overlying the folded clays was included 

a thick deposit of what is ~ow known as till (Montauk till member of Manhasset formation), 

and above this came- the "Quaternary division," embracing the more recent clay and sand 

deposits of Long, Staten, and New York islands (Hempstead gravel member of Manhasset 

formation and later deposits). "Some bowlder and drift deposits (Wisconsin) overlie this 

formation, but the main drift deposit, which was ·usually called alluvium, erratic block group, 

bowlder system, etc. (Montauk till member), underlies this formation." 3 The "Quaternary 

division" had three members, the lower being a blue clay, the middle a gray to buff clay, and 

the upper a sand. The clays were correlated with those of the Hudson and Champlain valleys.· 

There is little doubt, however, that the three members are really to be correlated, respectively, 

with what are now called the Gardiners. clay, the Jacob sand, and the Herod gravel member 

of the Manhasset formation. Their assignment to· a position above the main drift (Montauk 

till member of Manhasset formation) was doubtless due to the absence of this member of the 

Manhasset formation in Mather's type localities-an absence that is not at all uncommon. 

Two drifts were also distinctly recognized elsewhere in Mather's report. In speaking of the 

"Drift division" he said: "It is believed there is abundance of evidence of two epochs of strong 

currents, with a period of considerable duration of comparative repose between them." 4 This 

statement, which was lost sight of by subsequent writers, deserves recognition as one of the 

earliest if not the first explicit assertion in America of the duality of the drift period. Mather's 

statement in regard to fossils is also full of significance. "Most of then1 without any doubt 

occur below the drift, a few in the drift, and none or very few in the Quaternary deposits." 5 

Mather's conception seems to have been that the "lower drift" (Montauk till member of 

Manhasset formation) and the drift of the ridges (moraines) were the same and were deposited 

simultaneously as irregular hills, over or about which the deposits of his "Quaternary division" 

were laid down in standing water. After this a layer of pebbles, gravel, and bowlders, "which 

was called the upper drift," 4 was deposited over the whole. The deposits of his "Alluvial 

division," including fluviatile, lacustrine, marsh, and marine beds, all of which are still accumulating, completed the formations of the island. In explaining the od.gin of the drift Mather 

postulated diluvial processes requiring the action of strong currents laden with floating bergs 

and recognized two periods of great activity separated by a quieter period, in which the deposits 

of his "Quaternary division" were laid down. 

LITERATURE FROM 1843 TO 1878 (EARLY PALEONTOLOGIC PHASE). 

After the publication of the report. on the First district the drift deposits received little 

further attention for a period of 35 years, Mather's work during this period being accepted as 

authoritative and extensively quoted. 6 Of the new scientific contributions during this period 

1 Mather, W. W ., Geology of New York, pt. 1, 1843. 2 Idem, p. 272. a Idem, p. 123. 4 Idem, p. 158. a Idem, p. 264. 

6 Thompson, B. F., The history of Long Island from its discovery and settlement to the present time, 2 vols., New York, 1843. 
GEOLOGIC LITERATURE. 7 

by far the greater number related to paleontology, although several physiographic papers of 

importance appeared. · 

In Mather's report the older clays of Long Ishind had been assigned, on the basis of similarity to the New Jersey ·deposits, to the Cretaceous, but no fossils identifiable as 9retaceous . 

had been found. In the year in which the report appeared, however, a notice of the finding 

by William C. Redfield of Exogyra costata in a well in the drift at Brooklyn Heights was published. This was asserted to be the first authentic discovery of a Cretaceous fossil on the 

island. 1 

Four years later notes on more recent fossils in the drift near Brooklyn were given in 

another paper· by Redfield. 2 In commenting on this paper the editor said that the writer brought 

out the fact "that at least two periods of drift must be recognized, one of which was anterior 

to the deposit of clay in the valleys first referred to, ·the second that during which the shells on 

the summit o~ Montreal Island and Long Island were deposited." In .1848 E. Desor 3 reported 

shells in deposits of striated pebbles (Montauk member~) forming an anticline on the flanks 

of which were inclined sand and clays (Herod gravel member of Manhasset formation, etc.). 

Bouchepon 4 thought the structure might be due to a change of conditions caused by a shifting 

of the earth's axis. 

The next contribution on the geo.logy of the island was. by C. H. Davis,S who described the 

action of currents on the configuration of the entrance of New York Harbor. In 1850 and 

1851 appeared two papers by E. Desor, 6 who in the second of these papers explained certain 

phenomena of folding in the drifts about Boston as due to the settling of the deposits following 

the melting of buried ice masses, a conclusion of interest in view of the explanations later 

advanced in regard to the folding on Long Island. In 1854 a further note on the drift at 

Brooklyn was made by Redfield, 7 who .reported the finding of additional fossils and advanced 

the view that the drift period was greatly protracted but was later than the time of the so-called 

post-Tertiary (fossiliferous) deposits, which he regarded as marking a distinct epoch. Desor 7 

differed from Redfield on•this point, arguing that the deposit at Brooklyn was simply an 

exception to the common rule of Quaternary formations. 

The year 1857 was marked by the appearance of an important paper by George H. Cook,8 

who cited many 'i?stances of submerged timber and marshes, especially near Hempstead, 

Bab"ylon, and Islip. Cook showed that undercutting by the waves does not explain the occurrences, which are more likely due to a subsidence that is still going on at the rate of 2 feet in 

a hundred years. 

In an agricultural paper, published in 1859, ·Winston C. Watson 9 referred all of the island 

except the ledges near Hell Gate to alluvium, which he considered to have been formed by the 

sea in the same manner as the present beaches. 

Four years later Dana, 10 in the first edition of his Geology, placed the northern limit of 

the Cretaceous at Staten Island. He seems inclined to refer the older deposits qf Long Island 

to the Tertiary, although recognizing the glacial origin of the surface formations. He also 

illustrated the submarine valley off New York Harbor in connection with his discussion of 

Triassic rocks, saying: "The border, now submerged, has therefore in former times been dry 

land; it may have been partly so in the Triassic period." 11 

1 Am. jour. Sci., 1st ser., vol. 45, 1843, p. 156. 

2 Redfield, W. C., On the remains of marine shells of existing species found interspersed in deep portions of the hills of drift and bowlders in 

the heights of Brooklyn, on Long Island, near New York City: Am. Jour. Agr. and Sci., vol. 6, 1847, pp. 213-219; Am. Jour. Sci., 2d ser., vol. 5, 

1848, pp. llQ-111. 

a Proc. Boston Soc. Nat. Hist., vol. 2, 1848, p. 247. 

4 Idem, vol. 4, 1854, p. 180. 

5 Geological action of the tidal and other currents of the ocean: Mem. Am. Acad. Arts and Sci., new ser., vol. 4, .1849. 

oDes alluvions marines et lacustres et du terrain erratique de 1' Amerique du Nord: Bull. Soc. geol. France, 2d ser., vol. 7, 1850, pp. 623-631; 

[On the origin of contorted strata of sand and clay]: Proc. Am. Acad. Arts and Sci., vol. 2, 1851, pp. 282-283. 

7 Proc. Boston Soc. Nat. Hist., vol. 4, 1854, pp. 180-181. 

sOn a subsidence of the land on the sea coast of New Jersey and Long Island: Am. Jour. Sci., 2d ser., vol. 24, 1857, pp. 341-354. 

o 'l'he plains of Long Island: Trans. New York State Agr. Soc., vol. 9, 1859, pp. 485-505. 

10 Dana, J. D., Manual of geology, 1863. 

u Idem, pp. 441, 442. 
8 GEOLOGY OF LONG ISLAND. 

In 1867 Sanderson Smith 1 published the first description of the clays of Gardiners Island, 

together ~ith· an account of the fossils, which, with one or two exceptions, were believed to 

be of species still inhabiting the waters of the region, although as a whole they were characteristic of a more northern locality. 

Two ·years later Elias Lewis, jr.,2 men~ioned buried or submerged tree trunks and other 

evidences of subsidence, which he estimated had an1ounted to about 53 feet. 

J. S. Newberry 3 in 1871 announced the finding in the drift of cemented sand fragments 

resembling Triassic material but containing .angiospermous leaves not known to exist before 

the Cretaceous. · 

The geologic maps issued before 1873, including that of the New York State geologists 

in 1842, that of Edward Hitchcock and Jules Marcou in 1853, that of H. D. Rogers in 1858, 

and that of Sir W. E. Logan in 1868, but ·not that of William Maclure, had shown Long 

Island as Tertiary or alluvium. In 1873 C. H. Hitchcock and W. P. Blake, on a map of the 

United States prepared for the Ninth Census, showed the north shore of Long Island as Cretaceous. With this mapping Dana 4 took issue, stating that there were "no facts making the 

region Cretaceous." After receiving a letter of explanation from Hitchcock, Dana published 

another note, mentioning the source of the data supporting the map (Mather's observations) 

but expressing doubts of their value.5 A reply by Hitchcock 6 the following year quoted 

Mather and Cook as to the equivalency of the Long Island beds with New Jersey deposits of 

known Cretaceou~ age. · No mention was made by Hitchcock or Dana of the evidences advanced 

by Redfield or Newberry, but attention was called to them soon afterward by D. S. ~1:artin, 7 

and new evidences of angiospermous leaves were presented by Newberry 7 and of the· occurrence 

of Gryphrea by J. J. ~tevenson.7 Dana,8 however, in. 1875 reaffirmed his belief that the 

Qretaceous does not extend under Long Island. 

Before the discussion of the Cretaceous ceased, Elias Lewis, jr.,9 had called attention to 

the occurrence of clay bowlders up to 8 feet in diameter in the stratified. sands and gravels 

at Harbor Hill, "near Brooklyn." In 1875 Dana 10 published some v;ery important observations 

showing complexities in the New England drift similar to those on Long Island. He noted 

striated bowlders under the clays and "stony beds" (apparently loose till) over the sands, the 

clays having been folded and eroded before the sands were deposited. Some of Dana's descriptions are suggestive of a still older gravel, possibly to be correlated with th~ Mannetto gravel 

of the present ·:report. Unfortunately, he was content to refer most of the phenomena to 

unexplained variations·in the diluvial processes accompanying and following the glacial invasion 

(which was regarded as a unit) and made little attempt to develop the history of the region. 

Submergence was advocated to explain the higher deposits. In another paper 11 Dana stated 

that the glacial ice probably passed over Long Island and out to the edge of deep water 80 

miles farther south. The same statement appeared in the second edition of his "Manual of 

geology." The Sound, which was previously of less depth, was considered to have been occupied and partly eroded by large subglacial streams. Dana also believed that the land at that 

time stood at least 100 feet higher than at present and that the temperature was ·so low that 

marine life did not exist until after the retreat of the ice. The year 1875 was also marked 

by the appearance of a paper by Gabriel Furman, 12 who mentioned the occurrence of fossil 

shells. and described the breaks in the South Beach, and of a bibliography of Long Island, by 

H. Onderdonk, jr./3 which, however, contained few references to scientific publications. 

1 Notice of a post-Pliocene deposit on Gardiners Island, Suffolk County, N.Y.: Annals New York Lyceum Nat. Hist., vol. 8, 1867, pp. 149-151. 

2 Evidences of coast depression along the shores of Long Island: Am. Naturalist, vol. 2, 1869, pp. 334-336. 

a Proc. New York Lyceum Nat. Hist., 1st ser.,1871, pp.l49-150. 

4 Dana, J.D., Geological map of the United States, compiled for the Ninth Census by C. H. Hitchcock and W. P. Blake: Am. Jour. Sci.,3d 

ser., vol. 6,1873, pp. 64-66. · 

5 [Cretaceous of Long Island]: Idem, p. 305. 

o Hitchcock, C. H., Note upon the Cretaceous strata of Long Island: Proc. Am. Assoc. Adv. Sci., vol. 22, pt. 2, 18741 pp. 131-132. 

7 Proc. New York Lyceum Nat. Hist., 2d ser., No.4,1874, p. 127. 

a Dana, J.D., Manualofgeology,2d ed.,1875, p. 455. 

u Bowlder-like masses of clay in the Long Island drift: Pop. Sci. Monthly, vol. 2, 1873, p. 634. 

10 On southern New England during the melting of. tho great glacier: Am. Jour. Sci., 3d ser., vol. 10, 1875, pp. 168-183. 

11 Absence of marine life from Long Island Sound thro~gh the glacial and part of the Champlain periods: Am. Jour. Sci., 3d ser., vol. 10, 1875, 

pp. 280-282. 

12 Antiquities of Long Island, New York, 1875, pp. 1-434. 

1s Idem, pp. 435-469. 
GEOLOGIC LITERATURE. 9 

The next year, 1876, D. S. Martin 1 called attention to fossiliferous erratic bowlders of 

Silurian age, which he thought were drifted to the region by floating ice. In the same year a 

paper by Elias Lewis, jr.,Z gave a detailed account of the drifting sands of the island, including 

the composition, weathering, structure, rate of advance, destructiveness, and methods of controlling the dunes. · 

In 1877 were published four more papers of interest by the same author. In the first 3 

he described the large valleys of the south side of the island, noting the absence of streams 

competent to account for their formation, whi~h he thought was more likely due to the action 

of subglacial streams. The lack of postglacial erosion was emphasized in this paper for the 

fu'St time. Lewis regarded the land as having been submerged to a depth of 260 feet in glacial 

time, for stratified deposits are found up to. that level. In the second paper 4

• he pointed out 

the occurrence of thirty pronounced valleys between New York and Riverhead, some of which 

were said to extend across the Great South Bay to the ocean. Most of these valleys are characterized by a much steeper slope on the west or right-hand bank than on the east, and the 

general trend was said to be west of south. Deflection by the earth's rotation was suggested 

as the cause. In the third paper 5 the ridge or "backbone" appears for the first time to be 

definitely referred to the terminal moraine. A table of altitudes was given, and the suggestion 

was made that the amount of su brriergence during the formation can be determined from ((the 

presence and position of modified drift upon these hills and along their slopes." This suggestion 

indicates that Lewis believed the moraine to be older th~n the drift plateau on the north or the 

sloping plains on the south. The fourth paper 6 was devoted to the supposed changes of level 

indicated by the deposits of stratified sands and gravel that are recognized at different levels 

by the submerged tree trunks and peat beds still to be seen, by the fossils and lignife encountered in wells, and by the submarine channels off New York. The absence of bowlders on the 

plains south of the moraine was supposed to be due to their destruction by the advancing 

and receding shore lines. The present Montauk till member of the Manhasset formation was 

recognized as a distinct bed of "coarse glacial rubble in deep beds without fossils, * * * 

chiefly on the north side of the island." Below this were placed· the gravels (I-Ierod gravel 

1nember of Manhasset formation) and below the gravels the fossiliferous clays (Gardiners clay). 

The epoch was closed in 1878 by a paper by J. S. N ewberry,7 which, though a popular 

review of the geology, contained the statement that Cretaceous rocks underlie a large part 

of the island but that the finding of Tertiary beds is doubtful. In view of later developments 

this statement is of significance. 

LITERATURE FROM 1878 TO 1900 (EARLY DRIFT PHASE). 

The fourth period in the literature of the island began in 1878 with the first detailed discussion by Upham of the geology on the basis of the modern glacial theory, and continued 

. until the work of differentiating the drifts was begun. Knowledge of the island in this period 

was advanced mainly through studies of the drift by Upham and :Merrill, although, largely 

through the efforts of Hollick, there was a steady accumulation of paleontologic evidence as to 

the distribution of the Cretaceous along the north shore. The folding of the clays of the island 

and the formation of the submarine valley off New York also received a share of attention by 

Merrill and Lindenkohl, and the efficiency of subglacial streams as supplying many of the 

deposits and developing most of the existing topography of the island was advocated at short 

intervals throughout a large part of the period by Bryson. 

Upham's first discussion 8 was devoted to a consideration of the moraines, which he described, 

giving their heights. He predicted that their continuation would be found crossing New Jersey, 

1 On tho occurronco of Silurian fossils in the drift of Long Island: Am. Naturalist, vol. 10, 1876, p. 191. 

2 Tho formation of sand dunes: Pop. Sci. M:onthly, vol. 8, 1876, pp. 357-363. 

a On watercourses upon Long Island: Am. Jour. Sci., 3d ser., vol. 13, 1877, pp. 142-146. 

4 Ce.rtain features of the v.alleys or watercourses of southern Long Island: Idem, pp. 215-216 .. 

' Heights of Long Island: Idem, pp. 235-236. 

o Ups and downs of the Long Island coast: Pop.· Sci. Monthly, vol. 10, 1877, pp. 434-446. 

7 'l'ho geological history of New York island and harbor: Pop. Sci. Monthly, vol. 13, 1878, pp. 641-660. 

s Upham, Warren, Geology of New Hampshire, vol. 3, pt. 3, 1878, pp. 300-305. 
10 GEOLOGY OF LONG ISLAND. 

Pennsylvania, and Ohio, and differentiated the inner and outer moraines. In a second paper/ 

appearing the following year, Upham carefully and in the main accurately described the 

moraines, gave elevations, and discussed their composition. He mentioned the prevalence of 

till west of Roslyn and its absence to the east,· and described the Shinnecock Hills as composed 

of gravel. 2 He recognized two tills throughout Long Island and New England·, the lower being 

composed of thick, clayey, compact bluish material and the upper of thin, loose, oxidized material. The stratified character of the drift now known as Montauk was noted. Upham regarded 

the Wheatley Hills as composed of till and thought the Mannetto and Half Hollow hills to 

have been deposited like kames or in ice-walled channels. Later there was a local advance of 

the ice sheet, accompanied by the deposition of drift over these elevations. In this paper the 

outwash character of the plains was recognized for the first time, the preglacial age of the clays 

near Bethpage was announced, and the folding and beveling of the clays on Gardiners Island 

were described. The change of the sands lying- unconformably upon the clays to bowlder 

drift and vice versa was noted, and the deposits were correlated with those at Montauk, 

Bethpage, and Gay Head. Upham referred the Smithtown drainage system to erosion and 

described the numerous ponds that occupy old drainage channels. 

In the following year, 1880, appeared still another paper by Upham, in which he described 

the extension of the "lower" (Montauk till member of Manhasset formation) and "upper" 

(Wisconsin) till over New England/ stating that the "lower" till is from 2 to 50 feet thick and 

forms the drumlins, and that the "upper" till usually occurs as a very uniform mantle 5 feet 

or so in thickness. In this paper Uphan1 discussed the moraines of Long Island but made little 

addition to the data published in his preceding papers. 

In 1883 N. L. Britton 4 gave an account of further discoveries· of sandstone fragments containing Cretaceous fossils and predicted that correlation with the Cretaceous sandstones of 

New Jersey would be established. In the same year appeared the first of a long series of papers 

·by. John Bryson, a local- geologist. 5 In this and the following papers Bryson recorded his 

conviction that there had been no change of level of the island since the ice age, and that the 

deposits are the work of subglacial streams which built up the island as a barrier across the 

courses of the Connecticut and other rivers that had previously flowed southward to the ocean. 

The ·fossils are assruped to have been washed up by the currents. The subglacial waters were 

thought to have been finally diverted toward the west, cutting the East River channel. The 

year 1883 was also marked by the publication of T. C. Chamberlin's paper on the terminal 

n1oraine 6 with which the moraines of Long Island are correlated. Chamberlin showed two 

tnoraines in the eastern part of the island, but made the northern one e,nd abruptly not far 

from Port Jefferson instead of connecting with the other. His descriptions appear to be based 

entirely on the work of Upham, although in speaking of the southern plains he says: "These 

plains are undoubtedly due to glacial waters escaping over the moraine during its formation." 7 

In 1884 G. K. Gilbert 8 discussed quantitatively the .effects of the earth's rotation on the·. 

deflection of streams, mentioning the steep· right banks of the southward-flowing streams of 

Long Island. He pointed out that the conditions in rapidly deepening channels and in adjusted 

alluvial fans were not favorable to the action of this force. In 1885 A. Lindenkohl 9 described 

the deep submarine channel cut in blue clay for a distance of 100 miles from New York Bay, 

the presence of a bar of sand across it 75 miles from Sandy Hook, and the very deep ravine at 

the edge of the continental platform. He noted the fact that the channel is in line with the 

continuation of the moraine in New Jersey and suggested that the channel marks the position 

of the old ice front. . 

1 Upham, Warren, Terminal moraines of the North American ice sheet: Am. Jour. Sci., 3d ser., Yol. 18, 1879, pp. 81-92,197-209. 

2 Cf. Dwight, Timothy, Travels in New England and New York, vol. 3, 1822, pp. 283-336. 

a The succession of glacial deposits in New England: Proc. Am. Assoc. Adv. Sci., vol. 28, 1880, pp. 299-310. 

f Science, vol. 3, 1884, p. 25. 

s The glacial phenomena of North America as studied on Long Island, New York: Geol. Mag., new ser., vol. 10, 1883, pp. 169-171. 

& Preliminary paper on the terminal moraine of the second glacial epoch: Third Ann. Rept. U.S. Geol. Survey, 1883, pp. 291-402. 

~ Idem, p. 378. · 

_ s The sufficiency of terrestrial rotation for the deflection of streams: Am. Jour. Sci., 3d ser., vol. 27, 1884, pp. 427-432. 

9 Geology of the sea bottom in the approaches to New York Bay: Am. Jour. Sci., 3d ser., vol. 29, 1885, pp. 475-480. 
GEOLOGIC LITERATURE. 11 

The year 1886 was an active one in Long Island geology. N. L. Britton described the -

finding of fossil leaves, supposedly from the "Middle Cretaceous," in the clays at Glen Cove, 

and J. S. Newberry noted their occurrence at Glen Cove and Lloyd N eck. 1 

The principal contributions of the year were made by F. J. H. Merrill, who published a 

· detailed paper on the geology of the island. 2 In this paper, which was based on a five weeks' 

study of the region, he divided the deposits into clays, gravels, and till. Of the greater part of 

the clays he said: "From their character and position we may surmise that the brown and red 

plastic clays of I-Iuntington, Gardiners Island, and elsewhere belong to the age in question 

. [Tertiary]," although he noted the impossibility, in the absence of any unconformity, of determining where the Tertiary stops and the Pleistocene begins. He recognized, however, the similarity of the clays at Glen Cove to the Cretaceous of New Jersey, although he said: '~If the Cretaceous formation extends under the whole of Long Island it must occur at a very great depth, 

since deep sections at points east of Glen Cove do not record its presence." The gravels underlying the till were said to ·be "equivalent to and indeed identical with the yellow drift or preglacial drift of New Jersey." A belief in the superimposition of th~ mQraine on the gravels 

is possibly indicated by Merrill's statements that till is not more than a few feet thick even 

where the land is high. In describing ~1ontauk Point he mentioned a great thickness of "bowlder clay and hardpan of considerable depth covered by a shallow layer of till," apparently 

recognizing the existence of two till-like drifts. He regarded the shoving action of the ice 

as accounting for the elevation of the fossiliferous beds, for the lifting that formed the "backbone," and for the folding of the clays of the north shore and even of those south of the 

moraine, as at West Deer Park. The deep valleys of the north coast he explained as "plowed 

out by projecting spurs of ice." In regard to the amoun~ of postglacial erosion ~1errill differed 

from nearly every other writer on the subject, assuming it to be very extensive. 

In a second paper 3 Merrill discussed at greater length the folding produced by the ice, 

reiterated many of the conclusions outlined above·, and assigned an age much greater than that 

of the "Champlain" to the stratified fossiliferous deposits. 

In 1888 W J ~1cGee,4 in discussing the Columbia group, noted the occurrence of "subestuarine terraces" up to 250 feet above the sea and in interfluvial regions up to 400 feet. He recognized the fact that their age is greater than that of the moraines and suggested their correlation with the extra morainal drift and the gravel deposits of Long Island. The erosion 

interval between their deposition and that of the later drift was regarded by ~1cGee as of great 

length. The southward deflection of the rivers of the Coastal Plain he supposed to have taken 

place in Colun1bia time. 

· In the san1e year John Bryson 5 gave a partial record of a well at Woodhaven, near Jamaica 

Bay. Although noting the presence of lignite he referred all the materials to a glacial origin. 

This well was further discussed with full records in subsequent papers by Bryson 6 and Lewis. 7 

Bryson considered the glacial materials to extend to 298 feet; Lewis to 213 foot. No greensand 

was found. The great depth assigned to the glaeial deposits is of interest in connection with 

the assumption of W. 0. Crosby and others as to the Tertiary age of the gravels. 

In 1890 J. D. Dana 8 described the ehannels in Long Island Sound, ascribing them to the 

action of a Sound· river, which passed through what is now the North Fluke, near ~1attituck, 

into Peconic Bay, and then~e eastward to the ocean. Other streams passed out of the Sound 

at its east encl. The harbors of the north shore were ascribed to the ·action of subglacial streams. 

The presence of Cretaceous deposits hn,d up to that time been disputed, but Dana admitted that 

they occurred in the foundations of the higher parts of the island and on the north shore. He 

1 Fossil leaves in Staten Island and Long Island clay beds: Am. Jour. Sci., 3d ser., vol. 31, 1886, p. 403. 

2 On tho geology of Long Island: Annals New York Acad. Sci., vol. 3, 1886, pp. 341-364. 

a Some dynamic effects of the ice sheet: Proc. Am. Assoc. Adv. Sci., vol. 35, 1886, pp. 228-229. 

4 Three formations of the middle Atlantic slope: Am. Jour. Sci., 3d ser., vol. 35, 1888, pp. 367-388, 448-466. 

6 Am. Geologist, vol. 2, 1888, pp. 130-137. · 

e Bryson, John, Artesian well, Woodhaven, Long Island, New York: Am. Geologist, vol. 3, 1889, pp. 214-215. 

1 Lewis, Elias, jr., Woodham [Woodhaven) artesian well on Long Island: Am. Jour. Sci., 3d ser., vol. 37, 1889, p. 233. 

s Long Island Sound in the Quaternary era, with observations on the submarine Hudson River channel: Am. Jour. Sci., 3d ser., vol. 40, 1890, 

pp. 425-437. -
12 GEOLOGY OF LONG ISLAND. 

referred to the "Champlain stage" the bed of bowlder clay (Montauk till member of Manhasset 

formation), 10 to 150 feet thick, beneath the gravel. The channel off New York Harbor was 

thought to have been cut in "Jura-Trias" time (the Cretaceous and Tertiary being, accorcling 

to Dana, absent in its vicinity), possibly during an uplift accompanying a semiglacial epoch 

which he thought may have marked the close of the era. l-Ie quoted a letter f;rom E. Lewis, jr., · 

who presented evidences of well records showing that the Cretaceous clays, especially those at 

Deer Park and Bethpage, extend but short distances beyond their surface exposures. 1 David 

White 2 mentioned' the occurrence at Glen Cove of plant remains similar 'to those of the Cretaceous of Marthas Vineyard and correlated them with the flora of the clays of Amboy, N.J. J. S. 

Newberry 3 agreed with White as to the correlations and stated that he had traced the clays 

from New Jersey to Glen Cove and believed them to extend the whole length of the island. 

In 189.1 A. Lindenko.hl/ in a second contribution on the channel off New York, referred the 

erosion to glacial time and noted a subsequent subsidence of 210 feet. C. A. White,S in a review 

of published literature, recognized the presence of nonmarine Cretaceous deposits but was inclined 

to doubt the evidence of marine shells. F. J. H. Merrill, 6 in a paper on the I-Iudson Valley, 

ascribed the submarine channel to fluviatile rather than marine scour, suggested a "post-Champlain" submergence of 100 feet in New York, noted the occurrence of low terraces on Staten 

Island and the .mainland, and correlated the plains of .the south side of Long Island with the 

terrace of Hudson River, expressing his belief that a sloping plain could be cut on a rising or 

sinking coast without the formation of beaches. 

In 1892 W. I-I.· Dall and G. D. I-IaTris 7 expr:essed the opinion, derived from a review of 

published literature, that Cretaceous and probably Tertiary formations are present on Long 

Island. 

In 1893 McGee's geologic map of the United States 8 gave the nOTthern half of the island as 

Cretaceous. Bryson 9 published three papers, all in favor of'the subglacial theory. In the fll'st 

he argued for the subglacial rather than submarine or:igin of the channels of the plains, as 

Shaler had postulated for Marthas Vineyard. In the second he plaeed the ice limit south of the 

island rather than at the moraines and correlated the Olympia mounds of Washington with the 

Easthampton dunes, referring both to subglacial action. In the third he considered the Shinnecock Hills to be of kame origin and Peconic Bay to be due to the action of subglacial streams. 

Heinrich Ries 10 followed Merrill in referring a large part of the clays of Long Island to the 

Tertiary period, but accepted the Cretaceous age of those at Elm Point, Glen Cove, Mosquito 

Inlet, Glenwood, and Northport. Ries pointed out the similarity of the clays of West Neck 

and Center Island to those of Fishers Island and recognized their folded condition and position 

beneath sand, which in turn is overlain by till. He recorded stems and leaves from the clays 

of East Williston. 

The year 1893 was also marked by the appearance of the first contributions by Arthur' Hollick 

on the Cretaceous formation of the island. In the first of these papers 11 he argues, from the 

evidence of the flora, for a former land connection with the New England islands and the mainland. Long Island Sound he ascribed to ice erosion, the moraines to ice shove, and East River 

and its channels to overflow from glacial streams behind the moraine, assisted by tidal scour. 

The mo~aine was believed to have been cut through in the "Champla~" period of submergence 

1 Am. Jour. Sci., 3d ser., vol. 40, 1890, p. 430. 

2 On Cretaceous plants from Marthas Vineyard: Am. Jour. Sci., 3d,ser., vol. 39, 1890, pp. 93-101. 

a Bull. Geol. Soc. Amer!ca, vol. 1, 1890, p. 555. 

4 Notes on the submarine channel of the Hudson River and other evidences of postglacial subsidence of the middle Atlantic coast region: Am. 

J'our. Sci., 3d ser., vol. 41, 1891, pp. 489--499. 

liCorrelation papers, Cretaceous: Bull. U.S. Geol. Survey No. 82, 1891, pp. 84-86. 

o On the postglacial history of the Hudson River valley: Am. Jour. Sci., 3d ser., vol. 41, 1891, pp. 460-466. 

7 Correlation papers, N eocene: Bull. U. S. Geol. Survey No. 84, 1892, pp. 38-39. 

s Fourteenth Ann. Rept. U. S. Geol. Survey, pt. 2, 1894, Pl. II. 

~ Bryson, John, The glacial geology of Marthas Vineyard compared with that of Long Island·: Am. Geologist, vol. 11, 1893, pp. 210-212; The drift 

mounds of Olympia and Long Island: Idem, vol. 12, 1893, pp. 127-129; Origin of Peconic Bay and Shinnecock Hills, Long Island: Idem, vol. 12, 

1893, pp. 402-403. 

ION otes on the clays of New York State and their economic value: Trans. New York Acad. Sci., vol. 12, 1893, pp. 40-47. 

n Plant distribution as a factor in the interpretation of geological phenomena, with-special reference to Long Island and vicinity: Trans. New 

York Acad. Sci., vol. 12, 1893, pp. 189-202. 
GEOLOGIC LITERATURE. 13 

and the detached islands to have been thus formed. In the second paper 1 Hollick gave a summary of the previous writings on the island and a list of Cretaceous fossils. In the third and 

fourth papers 2 he recorded the finding of a palmlike fossil and described the plant. He quoted 

L. F. Ward as stating that the fragment is a Williamsonia and not a palm. 

In 1894 four more papers by I-I;ollick appeared. In the first 3 he described the distribution 

of fossiliferous ferruginous sandstone in the drift mainly west of Port Jefferson, and of the silicified Paleozoic fossils west of Lloyd Neck. These fossils occur mainly in the drift of the outer 

moraine, having been picked up by the ice at its first advance. The thick gravels were apparently considered by I-Iollick as the equivalent of the "y~llow gravel" of New Jersey. In the 

second and third papers 4 he reported further discoveries of Cretaceous flora at Eaton, Lloyd, 

and Oak necks, Glen Cove, and Seacliff. In the fourth paper 5 he described the occurrence of 

pebbles containing Paleozoic fossils as far east as Eaton Neck, and on this evidence correlated 

the gravels (Manhasset formation) with the "yellow grav-el" of New Jersey, notwithstanding 

their granitic character. lie did not clearly indicate the age of the· fossils but seems to have 

regarded them as pre-Pleistocene. In 1894 also the finding of Cretaceous leaves in water-worn 

sandstone fragments was recorded by C. L. Pollard, 6 and the occurrence of microscopic organisins, 

of supposed Tertiary age in the clays at a large number of localities was reported by I-Ieinrich 

Ries.7 It is jnteresting to note that all these forms were found in beds which later ·work has 

shown to be Cretaceous, and none in what are now known to be Pleistocene clays, either on Long 

Island or on Fishers Island, although these clays were then thought by Ries to be Tertiary. A 

second paper by Ries 8 describes the discovery of Cretaceous fossils at Little Neck, in Northport, 

making it necessary to place the boundary farther south than had previously be~n done. In the 

meantime W J McGee, 9 who had investigated the unconformities of the Coastal Plain, reached 

the conclusion that although there had been erosion, amounting to 200 or 300 feet, since the 

Lafayette epoch, only about a foot had occurred since the Columbia. The Lafayette was 

regarded as marine and as separated from the overlying Columbia by the greatest unconformity 

of Neocene and Quaternary time. N. S. Shaler 10 gave considerable attention during the same 

year to the cause of the folding in the clays and associated beds of the New York and New 

England islands .. l-Ie thought these folds to be s.i:milar to those of the RiChmond Basin a:nd to 

b~ due to downfolding and the production of a trough in the underl;ring crystalline rocks, with 

the resulting synclinoria! structure in the softer beds-in fact as a part of the disturbance 

marked in the Coastal Plain farther south by faulting which has been going on since the movement in the Appalachians ceased. Shaler further stated that the folding can not be due to ice, 

for the folds were eroded before the Wisconsin ice advance. The earlier ice invasions were not 

then recognized by Shaler. Ries, 11 in discussing the same phenomena on Fishers Island, referred 

thmn to ice shove. 

In 1895 A. M. Edwards 12 noted the finding of supposed fresh-water and marine Bacillariacere 

of Miocene age in clays near Rockaway. The deposits are now lmown to be Pleistocene or 

Recent, instead of Tertiary, as ·assumed by Edwards. Arthur Hollick, 13 in a paper on the folding 

I Preliminary contributiqn to our knowledge of the Cretaceous formation on Long Island and eastward: Trans. New York Acad. Sci., vol. 12, 

1893, pp. 222-231. 

2 A new fossil palm from the Cretaceous formation at Glen Cove, Long Island: Dull. Torrey Bot. Club, vol. 20, 1893, pp. 168-169; Some further 

notes upon Serenopsis kempii: Idem, pp. 334-335. ' 

a Some further notes on the geology of tho north shore of Long Island: Trans. New York Acad. Sci., vol. 13, 1894, pp. 122-130. 

4 Additions to the paleobotany of the Cretaceous formation of Long Island: Bull. Torrey Bot. Club, vol. 21, 1894, pp. 49-65; Recent investigations in the Cretaceous formation on Long Island, New York: Proc. Am. Assoc. Adv. Sci., vol. 42, 1894, p. 175. 

5 Notes on the northward extension of the yellow gravel in New Jersey, Staten Island, I.ong Island, and eastward: Proc. Am. Assoc. Adv. 

Sci., vol. 42, 1894, pp. 175-176. 

o Trans. New York Acad. Sci., vol. 13, 1894, pp. 180-181. 

71\ficroscopic organi">ms in the clays of New. York State: Idem~ pp. 165-169. 

sOn the occurrence of Cretaceous clays at Northport, Long Island: School of 1\fines Quart., vol. 15, 1894, pp. 354-355. 

o Graphic compariSon of post-Columbia and post-Lafayette erosion: Am. Geologist, vol. 12, 1894, p. 180. 

1o Tertiary dislocation"> of the Atlantic coast of the United States: Am. Geologist, vol. 13, 1894, pp. 143-144; Notes on tho Pleistocene distortions 

of tho Atlantic coast of the United States: Am. Jour. Sci., 3d ser., vol. 47,1894, p. 138; Pleistocene distortions of the Atlantic seacoast: Bull. Geol. 

Soc. America, vol. 5, 1894, pp. 199-202. 

11 Trans. New York Acad. Sci., vol. 14, 1895, p. 20. 

12 Tho occurrence of Tertiary clay on Long Island, New York: Am. Jour. Sci., 3d ser., vol. 50, 1895, p. 270. 

13 Dislocations in certain portions of the Atlantic Coastal Plain strata and thei.J: probable causes: Trans. New York Acad. Sci., vol. 14, 1895, 

pp. 8-20. 
14 GEOLOGY OF LONG ISLAND. 

of the clays and associated beds, noted that the disturbance is limited to the region covered by 

ice and is essentially superficial. He could see no evidence of preglacial topography. The 

'·'yellow gravel" (Manhasset formation) he regarded as the equivalent of the Lafayette. Heinrich Ries 1 ·referred a large number of the clay outcrops to the Tertiary, noting especially the 

similarity of the clays of Center Island, West Neck, and Fishers Island, which are "probably of 

the same age, possibly Tertiary." He recognized, however, the Cretaceous age of most of the 

clays of the north shore west of Northport. L. F. Ward/ in discussing the New Jersey equivalents of the C:Getaceous of Long Island in the same year, referred them .to the Lower Cretaceous. 

J. S. Newberry,S in writing on the clays of Amboy, N. J., correlated the clays of Long Island 

with the basal Cretaceous as developed in New Jersey. 

In 1896 N. H. Darton 4 published a geologic section across the west end of the island and 

gave a number of well records. A. :M. Edwards, 5 in a second paper on the Diatomace::e, described the finding of 70 species near Far Rockaway in clays supposed then to be of Neocene 

age but shown by late work to be unquestionably Pleistocene or Recent. Arthur Hollick published two papers during the year. The first 6 contained an account of the finding of lithologic 

evidences of marl on the north shore near Oyster Bay, of Cretaceous mollusks in greensand 

fragments in the drift at East New York, and of ferruginous concretions with mollusks in the 

deposits at Montauk. The second paper 7,presents the additional suggestion that the clays of 

Little Neck near Northport have been pushed sou_thward in a mass, as they should be north 

instead of south of the marl, fragments of which were found at Center Island. There seems to 

be some likelihood of error in such conclusions because of the assumption that fragments of 

ferruginous sandstone are weathered masses of marly deposits. W J :McGee,8 in another paper 

on the erosion epochs, placed the great erosion following t)le ·deposition of the Lafayette in the 

"Ozarkian" and assigned it to late Neocene time. He also recognized two interglacial periods 

of erosion. L. F. Ward 9 reintroduced the term "Island series," originally proposed by Mather, 

for the Cretaceous deposits of Long Island and correlated them on the evidence of- the flora 

with the clays of Raritan and Amboy, N. J. 0. C. ~1arsh 10 in the same year made the somewhat startling announcement, based on the Jurassic aspect of certain fossils found in ~1aryland, 

that all the deposits hitherto regarded as Cretaceous should be referred to the Jurassic. 

In 1897 John Bryson 11 noted erratics on the "kame moraine" near E_ast Williston, the 

first recognition of the outer moraine at this point. L. F. Ward 12 pointed out that the clays 

of Amboy, N. J., with which the clays of Long Island had been correlated, were distinctly 

younger than the Potomac of Maryland and Virginia. Lewis Woolman 13 published a number 

of records of wells near the west end of the island. · 

In 1898 John Bryson- 14 described some contorted drift with interbedded till [Montauk~] in 

Brooklyn. Arthur Hollick 15 assigned the clays of Amboy, on ·the evidence of their flora, to the 

"~1iddle Cretaceous," though not denying that the oJder Potomac might be Jurassic. In 

another paper 16 Hollick gave additional notes on the occurrence of lumps of Cretaceous clay, 

some of them with fossils, in the drift, and on the finding of marl concretions on Montauk. 

Warren Upham 17 described. the submarine channel off New York, postulating an uplift to 3,000 

feet at the end of the Tertiary period. He regarded the fossils of Gardiners Island as preglacial. 

I Clay industries of New York: Bull. New York State Mus. Nat. Hist. No. 12, 1895. 

2 The Potomac formation: Fifteenth Ann. Rept. U. S. Geol. Survey, 1895, pp. 345-346. 

a The flora of the Amboy clays: Mon. U. S. Geol. Survey, vol. 26, 1895. 

• Artesian-well prospects in the Atlantic Coastal Plain region: Bull. U.S. Geol. Survey No. 138, 1896. 

5 On the occurrence of Neocene marine Diatomacere near New York: Am. Naturalist, vol. 30, 1896, pp. 212-216. 

6 Geological notes, Long Island and Nantucket: Trans. New York Acad. Sci., vol. 15, 1896, pp. 3-10. 

7 Recent discovery of the occurrence of marine Cretaceous strata on Long Island: Proc. Am. Assoc. Adv. Sci., vol. 44, 1896, pp. 133-135. 

s Two erosion epochs: Science, new ser., vol. 3, 1896, pp. 796--799. 

9 Age of the Island series: Science, new ser., vol. 4, 1896, pp. 757-760. 

10 The geology of Block Island: Am. Jour. Sci., 4th ser., vol. 2, 1896, pp. 295-298, 375-377. 

n The Hempstead Plains, Long Island: Am. Geologist, vol. 20, 1897, pp. 61-65. 

12 Prof. Fontaine and Dr. Newberry on the age of the Potomac formation: Science, new ser., vol. 5, 1897, pp. 411-423. 

1a Artesian wells in Cretaceous strata on Long Island, New York: Rcpt. New Jersey Geol. Survey for 1896, 1897, pp. 155-165. 

u Drift formations of Long Island: Am. Geologist, vol. 22, 1898, pp. 245-247. 

u. The age of the Amboy clay series, as indicated by its flora: Am. Geologist, vol. 22, 1898, pp. 255-256; Science, new ser., vol. 8, 1898, pp: 467-468. 

16 Geological notes, Long Island and Block Island: Trans. New York Acad. Sci., Yol. 16, 1898, pp. 9-18. 

17 Glacial history of the New England islands, Cape Cod, and Long Island: Am. Geologist, vol. 24, 1899, pp. 79-92. 
GEOLOGIC LITERATURE. 15 

He recognized an early ice advance, producing the folding, as occurring before the advance that 

produced the moraines, and he suggested that the Kansan, ·Illinoian, Iowan, and early 

Wisconsin stages of glaciation in the Mississippi Valley may have taken place between the 

folding and the formation of moraines. The topography of the plateau and its deep valleys 

Upham thought -to be due to the deposition of gravel around ice blocks. He pointed out the 

thinness of till near the limits of glaciation. 

In 1900 W. 0. Crosby 1 stated the principal formations of the island to be (1) crystalline, 

(2) Cretaceous, (3) Neocene Tertiary, and (4) terminal moraine. The surface gravels both 

north and south of the moraine, although granitic in character, he correlateu with the "yellow 

gravels" of New Jersey and regarded as Lafayette. The ·"blue· clay," which was supposed to 

form a uniform floor beneath the gravels, he referred to the Chesapeake. The gray gravels, 

notwithstanding their high percentage of granitic material, he likewise included in the Tertiary. 

These three formations are probably to be correlated with the ~fanhasset, Gardiners, and Jameco 

formations of the present report. Crosby supposed the Cretaceous to be confined to the northern part of each neck of the north shore and the Tertiary to be farther south on the same necks ' 

but going under the surface near the head of each bay or harbor. The exposures at East Williston, Bethpage, ·and West Deer Park he regarded as Tertiary and supposed to have been brought 

up by the pressure and thrust of the ice sheet. He considered the north-shore scarp to have 

been worn back by lateral tributaries of Connecticut and Housatonic rivers during an uplift of 

3,000 feet preceding the ice advance. 

In the same year F. J. H. Merrill 2 postulated an origin for the white Cretaceous clays of 

Long Island from the decomposition of the Lower Silurian [Ordovician] limestone and argued . 

for the origin of Long Island Sound and East and North rivers through the solution of such 

~ocks. Heinrich Ries 3 published an account of the clays, which, however, was essentially the 

same as an earlier paper. 

LITERATURE FROM 1901 TO 1908 (LATER DRIFT ~HASE). 

Previous to 1901 no systematic studies of the island as a whole or of any considerable part 

of it had been attempted, with the exception of Mather's investigations from 1837 to 1843, 

although the detailed reconnaissances of Upham and Merrill approached such studies in 

character. In the period beginning with 1901, however, a number of reports have appeared 

that haV'e been based on detailed and systematic field observations covering not only the 

surface deposits but also the underground geology as worked out from the records of many 

hundreds of wells and borings. The attempt has been made, moreover, to approach the problem 

from the standpoint of the student of geologic history and to apply knowledge of the drift 

succession in other parts of the country to the differentiation of the deposits of Long Island. 

The first publication of the period was the geologic map of Long Island, 4 based on field 

work by J. B. Woodworth and J. E. Woodman and issued by the Geological Survey of New 

York. On this map the moraines were mapped in detail, and the fact that the later moraine 

crosses the older one near Lake Success w:as pointed out for the first time. The Westbury, 

West (Mannetto), and Half Hollow hills, which' later work has shown to be much older, w'ere 

shown as moraines, and the gravels of the ridge at Rockaway, now known to be Pleistocene, 

were referred to t_he Tertiary. In the same year J. B. Woodworth 5 published the· results of a 

careful study of the ·oyster Bay and Hempstead areas. He mapped the outcrops of, Cretaceous 

rocks and clearly pointed out the Pleistocene nature of the thick gravels of the north shore 

(Manhasset formation) and the included bowlder bed (Montauk till member ·of Manhasset). 

In the region north of the moraine these gravels were also carefully mapped and their probable 

extension southward was indicated. Woodworth recorded the presence of underlying blackish 

or bluish clays, but considered that they are "not certainly of glacial origin and perhaps to be 

t Outline of tho geology of Long Island in its relation to the public water supplies: Tech. Quart., vol. 13, 1900, pp. 1C0-119. 

2 Origin of the white n.nd variegated clays of the north shore of Long Island: Annals New York Acad. Sci., vol. 12, 1900, pp. 113-116. 

a Clays of "N"cw York: Bull. New York State Mus. No. 35, 19.00. 

4 Geologic map of New York, 1901, Long Island and Lower Hudson sheets. 

o Pleistocene geology of portions of Nassau County and the Borough of Queens: Bull. New York State Mus. No. 48, 1901, pp. 617-670. 
16 GEOLOGY OF LONG ISLAND. 

' . regarded as of Tertiary or older age." l-Ie admitted that the altitude of much of the Cretaceous 

· ' material is due to ice shove but recognized a strong erosion unconformity between the Cretaceous and the Pleistocene. The bowlder bed in the Manhasset formation was recognized at 

many points and its change laterally from till-like to stratified materials noted. lie described in 

detail the great erosion period following the early Pleistocene deposition but preceding the deposition of the last drift, which had :riot been recognized by Crosby and had been explicitly denied 

by Hollick. The deposition of the high gravels at I-Iarbor I-Iill Woodworth ascribed to subglacial 

streams. He discussed the straight face of the moraine west of Jamaica but reached no definite 

conclusion as to its origin. He suggested that the Jamaica Bay depression is an original constructional feature of deposition and that the Rockaway ridge is a remnant of the Tertiary. 

The moraine he distinctly recognized as superimposed on the Manhasset, representing simply 

a local thickening of the till sheet. The geologic history as outlined by Woodworth is as follows: 

(1) Erosion of the Cretaceous, (2) deposition of earlier Columbia deposits (Herod gravel member 

of Manhasset formation), (3) advance of the ice and deposition of the bowlder bed (Montftuk 

till.member of Manhasset), (4) completion of the deposition of the Columbia (Hempstead gravel 

member of Manhasset), (5) long period of erosion, (6) invasion by latest ice sheet (Wisconsin), 

and (7) retreatal deposition in glacial lakes. While many of the points brought out were not 

new, this paper was in many ways the most important that had yet appeared, as Woqdworth 

did not stop with general statements but systematically described and discussed the various 

deposits and differentiated them for the first time on a map. 

A paper by G. B. Shattuck 1 presented the following summary of the later Coastal Plain 

. ·history: (1) Subsidence and deposition of the Lafayette, (2) elevation and erosion of ·the 

Lafayette, (3) subsidence and deposition of the Sunderland, (4) elevation and erosion of the 

Sunderland, (5) subsidence and deposition of the Wicomico, (6) elevation and erosion of the 

Wicomico, (7) subsidence and deposition of the Talbot, (8) elevation and erosion of the Talbot, 

and (9) subsidence and deposition of the Recent deposits. Shattuck stated that because of the 

difference in method of classification exact correlation with the New Jersey deposits could not 

be made, and he presented a table in which he suggested the correlation of the -Sunderland with 

parts of Cape May, Pensauken, and Bridgeton; of the Wicomico also with parts of the Cape 

May, Pensauken, and Bddgeton; and of the Talbot with parts of the Cape May and Pensauken. 

In the following year, 1902, appeared the New York folio, 2 in which that part of Long 

Island lying west of the area treated by Woodworth was fully described. In this folio an early 

Pleistocene elevation, during which the submarine channel was ~xcavated and the channels 

of the East River were cut by a tributary stream, was assumed,3 and the possibility of earlier 

glaciers similar to the last was suggested.4 The possibility of old Pleistocene gravels correlatable with the Pensauken of New Jersey occurring beneath the late till of Staten Island was 

pointed out,5 but no inen,tion of the1r occurrence on Long Island was made. At least two ice 

advances were considered to have occurred in the region. The superimposition of the relatively 

thin moraine on older deposits was likewise recognized. The steepness of its face w~st of 

Jamaica was not attributed to marine erosion. The plains of the south side of the island were 

described, and the fact that their topography is not that of normal outwash plains was pointed 

out. The Rockaway ridge was attributed to marine action in late glacial or postglacial time, when 

the land was somewhat depressed. Although at least two glacial invasions in the region were 

admitted and the occurrence o£ stratified gravels below the Wisconsin till was noted, the existence 

of any extensive deposits of an earlier stage does not appear to have· been recognized, the 

materials beneath the till apparently being referred to an earlier deposit of the· same stage 

instead of to a distinct deposition separatedfrom the last ice invasion by a long period of erosion, · 

as postulated b"'y Woodworth in the adjoining area ·on the east. . 

1 The Pleistocene prol>lem of the north Atlantic Coastal Plain: Circ. Johns Hopkins Univ. No. 152, 1901; Am. Geologist, vol. 28,1901, pp. 87-107. 

2Merrill, F. J. H., and others, New York City folio (No. 83),. Geol. Atlas U.S., U.S. Geol. Survey, 1902. 

a Willis, Bailey, and Dodge, R. E., Physiographic features of tpe district: Idem, pp. 17-18. 

• 'Villis, Bailey, Outline of geologic history: Idem, pp. 2-3. 

5 Salisbury, .R. D., Pleistocene formations: Idem, pp. 11-17. 
GEOLOGIC LITERATURE. 17 

G. B. Shattuck 1 published a second paper during. the year reiterating the Coastal Plain 

subdivisions proposed in l 901. 

In 1903 the present writer, assisted by A. C. Veatch and o-thers, began a detailed study of 

the geology and water resow·ces of the island. In a preliminary notice by Veatch, 2 who devoted 

himself largely to collecting well records and studying underground geology, the "uniform blue 

clay floor" of supposed Chesapeake age, which had been postulated by Crosby and others, was 

shown to be absent, and the presence of a deep buried valley across the island west of Jameco 

was pointed out. In this notice 'tho present writer was credited with the discovery in the 

vVheatley I-Iills of hitherto unrecognized grave] deposits [Mannetto] older than the Manhasset 

formation and with the recognition of terraces of the Manhasset south of the moraine near 

Bethpage. A detailed section at the top of the hill west of Mellville was given, showing a considerable thickness of quartz gravels containing a few weathered granitic pebbles -and underlain 

by sands, clays, "arkose," etc., of pre-Pleistocene age. The dip of the Cretaceous was deterJnined for the first tin1e, well borings showing it to be about 65 feet to the mile in the direction 

S. 23° E. 

In anotl~er paper 3 ]fuller and Veatch called attention to the extension of the Cretaceous 

to the Bethpage and Wyandance localities and to the discovery of greensand in the Millville 

section. .The absence of Tertiary deposits was noted, the older gravels having been determined 

to be early Pleistocene. The supposed Chesapeake clays were separated into a number of 

formations, all of Pleistocene age. Gravels of glacial origin and of supposed Kansan age were 

noted beneath the early Pleistocene clay in the buried valley west of Jamaica. The occurrence of gravels of the Manhasset formation was recognized as far east as Montauk Point and 

their age was given as probably Iowan. The thinness of the outwash is emphasized for the first 

time. Later the present writer 4 discussed two of the pre-Wisconsin· ·deposits in more detail. 

The older, deeply weathered gravels of the Westbury or Wheatley Hills and the West, or Mannetto Hills were correlated with the Pensauken formation of New Jersey and assigned provisionnlly to water deposition during a pre-Kansan stage of glaciation, arid their correlation with 

McGee's high-l~vel Columbi~ of New Jersey and farther south and with the deposits of the 

:Monongahela and Alleghany terraces was suggested. The discovery of a glacially derived gravel 

[Jafl!eco] resting unconformably on·the old weathered gravel [Mannetto] and of an extensive 

bed of Pleistocene clay [Gardiners] directly abov'e it and tlfe recognition of an epoch of folding 

by ice thrust were credited to Veatch, who assigned the glacial grave] to the Kansan, the clay 

to the Yarmouth, an.d the folding. to the Illinoian stage. On the basis of these discoveries the 

unfolded Manhasset was referred to the l.owan. Veatch, 5 in a paper published a few weeks 

later, described the clays and old gravels of Gardiners Island, their contained fossils, ~nd their 

folding and erosion. IIe gave the following succession for Long Island: (l) Pensauken gravel 

[Mannetto], glacial; (2) Jameco gravel, glacial;. (3) Sankaty clay [Gardiners], interglacial; (4) 

:Manhasset, glacial; (5) Wisconsin, glacia~. The correlations with the various.glacialstages are 

the smne as in the preceding paper. 

Four other papers relating to Long Island appeared during the year. E. P. Buffet 6 discussed· the topography, bowlders, and beaches from the standpoint of the geographer. Arthur 

I-Iollick7 gave a list of paleontologic accessions from Glen Cove. IIein:rich Ries 8 referred the 

clays of Staten, Long, and Fishers islands to the Cretaceous, no Pleistocene clays on Long Island 

being 1nentioned. J. W. Spencer 9 described the subn1arine channel off New York, stating that 

its continuation Inay. be .inferred to a depth of 8,500 feet below the "cul-de-sac" of Lindenkohl. 

1 The Pleistocene problem in Maryland: Science, new ser., vol. 15, 1902, pp. 906-907. 

2 Notes on tho geolo;;y of Long Island: Science, new ser., vol. 18, 1903, pp. 213-214. 

a Results of the resurvey of Long Island: Science, new ser., vol. 18, 1903,pp. 729-731. 

• Probable pre-Kansan and Iowan deposits of Long Island: Am. Geologist, vol. 32, 1903, pp. 308-312. 

G'l'he diversity of the glacial period on Long Island: Jour. Geology, vol. 11, 1903, pp. i62-i7G. 

o Some glacial conditions and recent changes on Long Island: Jour. Geography, vol. 2, 1903, pp. 95-101. 

7 Field work during 1901 in the Cretaceous bods of Long Island:· Fifty-fifth Ann. Rept. N:ew York State Mus., 1903, pp. r 48-r 51. 

a Clays of tho United States east of the Mississippi River: Prof. Paper U. S. Geol. Survey No. 11, 1903, pp. 173-1i5. 

o Submarine valleys off the American coast and in the North Atlantic: Bull. Geol. Soc. America, vol. 14, 1903, p. 214. 
18 GEOLOG:Y OF LONG ISLAND. 

The cutting he thought to be mainly post-Miocene·, although it may have begun earlier, being 

completed in post-Lafayette but pre-Columb~atiJl?-e. The Connecticut he regarded as flowing 

eastward, stating that there is no evidence of a channel across Long Island. 

The year 1904 was characterized by a marked falling off in the literature dealing directly 

with Long Island. Arthur Hollick 1 described a number of new discoveries of fossil plants, 

including one from "Cretaceous shale" at Montauk Point. In a letter Dr. Hollick states that 

this was not fqund in place and that the Cretaceous does not at the present time show above sea 

level, hence his observations are really in accord with those of the present writer, who regards 

all the deposits as Pleistocene. C. E. Peet, 2 who studied the drift of the I-Iudson Valley, found 

'masses of till both over and under the drift and clay bowlders within it, especially in the southern 

part of th~ ~rea. Over the clay he noted also in many places a gravel with an undulating topography [Manhasset~], the contact app~aring as if the gravel had been pressed into the clay. 

In-1905 W. H. Hobbs 3 published two papers in which he gave a number of sections across 

Ea~t. Ri~er t~at showed the underlying rock to be mainly gneiss, with only two narrow local beds 

of limestone. ~e th~refore regarded the channel as due· to faulting and jointing rather than 

to sohition. o( the limestone. In the same year the first presentation of the Pleistocene stages 

now recognized .was made by the present writer 4 in a paper on Fishers Island. Although this 

paper did not deal primarily with the larger island, the Long Island succession was described 

ill qetail; all th.e diviSions except the Hempstead ;t~d Vineyard were recognized and names 

were --~pplied to the Gardiners, Jacob, Herod,· and Montauk stages and substages.· A further 

<?<;>~£~~~l!t~ofl: .t? the _literature o~ the submarine Hudson channel was made by J. W. Spencer, 5 

who .. stat~d that he could trace 1t to a depth of about 9,000 feet below the surface of the sea. 

· · 'Eariy ip 1~06 there appeared in Chamberlin ar:td Salisbury's text book 6 a geologic map of 

the l!_Q.~t.ed ~t_ates ~ompiled by Bailey Willis, on w~ich the north side of Long Island is shown 

a~. C~et~,qe()US. The present writer 7 summarized the Pleistocene stages of the region an,d 

~e~9ribe~· the Long Isla~d subdivisions and their equivalents on the mainland. An important 

coJ:t.t:r;ibution was made by A. C. Veatch 8 in a chapter of the report giving the results of the 

l.illderground-water investigations by the United States Geological Survey. The Pleistocene 

formations recognized were identical with those discussed .in the earlier paper by the same 

aut~or in 1~03, the new stages differentiated by t~e present writer, including the Jacob, Herod, 

Montauk, and Hempstead of this report, not being recognized. Veatch's report was prepared 

two years ·previous to its publication and before the subdivisions mentioned had been differentiated. Although no new stages were recognized, the paper was of importance as presenting 

a detailed statement of the subdivisions as they had been worked out in the first season's field 

work and fuller d_escriptions than had been given in the preliminary papers of 1903. Correlatiqns ~ere made with· the deposits. of Marthas Vineyard, but none were attempted with the 

drifts of the· central part of t~e country nor with the Pleistocene format_ions of the Atlantic 

Coastal Plain. An important contribution to the knowledge of the Cretaceous deposits was 

made, t4es~ .accumulations being reg~rded as the equivalents of the Raritan and Matawan 

form~tions of New Jersey and as being of Upper Cretaceous age. Veatch gave an extended 

discussion .of the origin o.f Long Island Sound, which he ascribed to excavation by a westwardflowing stre_am crossing western Long Island and joining the submarine channel off Sandy Hook. 

In the !3a~e year Arthur Hollick 9 a<;lded to the information regarding the Cretaceous, and . 

Q .. B~ ·s4at.tuck's. final report on the Pleistocene deposits of Maryland 10 was published, in which 

he still further elaborated his views. 

· 1 Additions to the paleobotany of the Cretaceous 'formation on Long Islan:d, No. II: Bull. New York Bot. Garden, vol. 3, 1904, pp. 403-418. 

2 Glacial and post glacial history of the Hudson and Champlain valleys: Jour. Geology, vol. 12, 1904, pp. 415-469, 617-660. 

a Origin of the channels surrounding Manhattan Island, New York: Bull. Geol. Soc. America, vol. 16, 1905, pp. 151-182; The configuration 

of the rock fioor of Greater New York: Bull. U.S. Geol. Survey No. 270, 1905, 93 pp, 

4 Geology of Fishers Island, New York: Bull. Geol. Soc. America, vol. 16, 1905, pp. 367-390. • 

5 The submarine.great canyon of the Hudson. River: Am. Jour. Sci., 4th set., vol. 19, 1905, pp. 1'-15. 

a Chamberlin, T. C., and Salisbury, R. D., Geology, vol. 2, 1906, colored plate. . 

7 Glacial stages in southeastern New England and vicinity: Science, riew ser., vol. 24, 1906, pp. 467-469. 

s Outline of the geology of Long Island: Prof. Paper U. s: Geol. Survey· No. 44, 1906, pp. 15-52. 

9 The Cretaceous fiora of southern New York and New England:· Mon. U.S. Geol. Sur.vey, vol. 50, 1906; 

10 Pliocene and Pleistocene, ~arr~a>Jd Geol. Survey, 1906. 
GEOLOGIC LITERATURE. 19 

No important papers bearing on the geology of Long Island were published in 1907, but 

in ~908 appeared a paper by F. G. Clapp 1 that was of unusual interest as showing the existence 

of the Long Island subdivisions or t.heir equivalents in northern Massachusetts, in New Hampshire, and throughout Maine. The latest contribution to Long Island geology at the time of 

writing (1908) is an article by W. 0. Crosby,Z who reiterated his earlier belief in the unity of 

the glacial epoch and assumed only a single invasion, the Wisconsin. He referred the Gardiners clay to a Tertiary ep;ch (that of the Chesapeake group of the :Miocene). The Pleistocene 

character of its fossils as determined by W. H. Dall and other competent paleontologists and 

the nonagreement of the deposits in charact.er nor elevation 'Vith the adjacent Miocene 

deposits of New Jersey were disregarded. ·The large amount of granitic material, which is 

entirely at variance with the character of the Tertiary deposits elsewhere, especially with the 

clayey and marly deposits of this age in New Jersey, and the presence of large erratic bowlders 

in the J ameco and :Mannetto were likewise regarded as without significance· and these two 

formations were referred to the Oligocene. The heavy :Montauk member of the l\1anhasset 

formation, several times as thick as the Wisconsin, was not recognized. 

LITERATURE OF CONTEMPORARY PLEISTOCENE DEPOSITS IN NEW JERSEY. 

In 1891 R. D. Salisbury published ·the first of a se~ies of reports on the surface geology of 

New Jersey which has a direct b~aring on the geologic history of Long Island. · ·In this. report'~ he 

compared the older extramorainic drift, which he regarded as the equivalent of the oldest· drift 

of the interior, n,nd the younger morainic drift. The weathering of the former he gives as at 

least 30 feet, but that of the latter as only 2 or 3 feet. In the second report 4 he gave. considerable attention to the ''yellow gravels," which were shown to be a complex series, in part of 

Tertiary and in part of Pleistocene age, containing some apparently berg-dropped . bowlders. 

The essential completion of their present topography before the advent of the last ice sheet 

is recognized. The following tentative stages are postulated: (1) Submergence to 400-foot 

level and deposition of gravel; (2) elevation and long-continued erosion reducing the surface 

by 120 to 150 feet; (3) depression to 150 feet below the present level; with deposition of gravel 

and possibly the .introduction of ice-rafted bowlders; ( 4) elevation and moderate erosion to 

the present level; (5) slight depression and formation of low terraces, and (6) elevation of about 

.40 feet. In the third report 5 he applied the name Beacon Hill to older gravels and Pensauken 

to the next younger. A new stage of submergence, marked by the deposition of loaniy ~ilts 

("Jamesburg loam") with complex nonerosion topogr~phy, was postulated as oc·curring after 

the erosion of the Pensauken and before the deposition of the gravels of the low terraces. In 

his fourth report 6 Salisbury subdivided the Pensauken into a lower part, consisting of horizontally stratified loamy arkose sand, and an upper part, consisting largely of irregularly stratified lenticular beds of gravelwhich contain scattered ice-rafted bow~ders and in which many of 

the granitic pebbles are deeply w~athered. The upper part is clayey in many places in the 

northern part of New Jersey and presents vertical faces in artificial cuts, but this character 

does not prevail farther south. With few exceptions the gravel is heterogeneous both physically and lithologically, its constituents ranging from half an inch to 4 feet in diameter (compare 

with Montauk, .p. 132). The "J~mesburg loam" was described. as an imperfectly stratified 

surface mantle, in places much bent and contorted as if shoving or thrusting action had taken 

place. Its correlation with. an older drift is suggested. Elsewhere Salisbury referred the 

Pensauken definitely to the Lafayette, stating: "There can no longer be any doubt that the 

Pensauken is the equivalent of the Lafayette formation of the south." The report for 18~5 1 

was mainly descriptive of new localities, but the presence of clays in the Pensauken was noted, 

and the questionable character of the evidence for the separation of the "Jamesburg loam" 

pointed out. In the next report .by Salisbury and G. N. Knapp, 2 the noticeable till-like chart Complexity of the glacial period in northeastern New England: Bull. Geol. Soc. America, vol. 18, 1908, pp. 505-556. 

:Outline of the geology of Long Island: Science, new ser., vol. 28, 1908, p. 936. 

3Preliminary paper on drift or Pleistocene formations of New Jersey: Rept. New Jersey Geol. Survey for 1891, pp. 35-108. 

~surface geology: Id~m for 1892, pp. 33-166. 

6Surface geology: Idem for 1893, pp. 33-328. 

a Surface geology: Idem for 1894, pp. 1-150. 
GEOLOGY OF LONG ISL~~D. 

acter of certain parts. 9f th~ Pensauken and the presence of striated bowlders were mentioned, 

and a new subdivision of th~. :Pensauken with Beacon Hill affinities was suggested. The Pensauken was at this time· regarded as glacial. In the· report for 189~ 3 this subdivision was 

speciji.cally defined as a gravel, sand, and loam formation, locally clayey, distinctly higher 

than tl).e .Pensauken, and intermediate in age between the Pensauken and the Beacon Hill. 

The name Bridgeton was applied to it and it was tentatively correlated with the ·Lafayette; 

the Pensauken was considered as "probably contemporaneous with an early glacial epoch 

(Kans~n o~ Albertan)." The "Jamesburg loam" seems to be dropped from the list of formatiqns, apparently for the reason that later work had shown it to be simply a surfiCial phase of 

the older deposits. The report for 1898' dealt largely with the Cape May formation, or the 

terraces at 40 feet or thereabouts . 

. The physiographic history of the State was discussed in the report on physical geography,5 

but nqtpj.ng new was adduced . 

. ~.report by R. D. Salisbury, I-I. B. Kiill}mel, C. E. Peet, and G~ N. Knapp 6 gave an interesting summary of the Pleistocene history of New Jersey. The "only glacial formations which 

have been distinctly recognized in New Jersey are those of the Kansan ( n and Wisconsin 

formations." 7 The clays below sea level around Hackensack were regarded as equivalent 

to the "Champlain and Hudson River clays." ·A post-Wisconsin submergence of 40 feet in 

the southern part of the State was recognized and one of 100 feet in the northern part was suggested. 

THE PRESENT REPORT. 

Although dealing w:ith the pre-Pleistocene as well as the Pleistocene geology of the island, 

the present report gives chief attention to the latter, largely because the new discoveries have 

related mainly to the Pleistocene formations. The report attempts, however, to arrange the 

Cretaceous beds for the first time in a number of groups, which are in general sufficiently dis-. 

tinctive lithologically to admit of the assjgnment of outcrops to their proper places with some 

degree of certainty. Until information that will permit a more precise definition is available, 

however, it does not appear desirable to apply new formation names to them. Their distribution is shown on Plate I (in pocket) and figure 56 (p. 69). The results of the Pleistocene work 

are best shown by the following table, in which the stages recognized, their origin, the depositsby which they are characterized, and their probable correlations with the deposits of central 

United States are given . 

. 1 Surface geology: Rept. New Jersey Geol. Survey for 1895, pp. 1-lll. 

2 Surface geology; Idem for 18!Hi, pp. 1-24. 

a Surface geology: Idem for 1897, pp. 1-22. 

4 Report on surface geology: Idem for 1898, pp. 1-42. 

c; The physical geography of New Jersey: Final Rept. New Jersey Geol. Survey, vol. 4, 1895. 

o The glacial geology of New Jersey: Final Rept. New Jersey Geol. Survey, vol. 5, 1902. 

1 Idem, p. 189. 
GEOLOGIC LITERATURE. 21. 

Pleistocene events on Long Island. 

Probable time 

Stage. Substage. Character. Represented by- '!'hick- equivalents in ness. Mississi~pi and 

Ohiova eys,etc. 

Harbor Hill. Glacial. Harbor Hill or inner moraine, and associated till and Fer.!. outwash. 

Wisconsin. Early Wisconsin. 

Ronkonkoma. Glacial. Ronkonkoma or outer moraine, and associated till 

and outwash. 

Intl'rglar.ial. Great erosion nnconrormity, and Vineyard for- Sang am on (?~ 

Vineyard: mat.ion, consisting or marine··deposits and peat. Iowan (?), an ·Peorian ( ?)·. 

Hempstead gravel member. 50-75 

I Hempstead.· 

cl Ice erosion unconrormity . • sa 

~ 

~ :M:ontank till memher: 

Manhasset. Glacial, 1. 'l'ill. 0-HO+ 

~ 2. Gravel. 

. Montauk. ~ 3. Till. lllinoian • 

..c:: 

= t:e Ice erosion unconformity. ::a 

Herod. Herod gravel member. .50-75 

Jacob. 'rransitional. Jacob sand; 

0 

Gardincrs. Interglacial. I Gardiners clay. Yarmou.th. 

Jmncco. Glacial. Jameco gravel. K~san. 

Post.~Mnnnetto. Interglacial. Great erosion unconformity. Afto,nlan. 

Man net to. Glacial. Mannetto gravel. Pre-Kan~an. 

In addition to the detailed descriptions of the various deposits, the older Pleistocene. subdivisions, including all those antedat~g the Wisconsin, are for the first time shown on a map. 

The probable extension of the formations along the New England coast toward the northeast, 

their correlations with the New Jersey formations, the detailed geologic history of the island, 

the orogenic movements that have taken place upon it, and the relative length of its various 

geologic stages also receive attention. Special consideration is given to the topographic and 

physiographic features, including the various forms of Wisconsin drift, the submerged Sound 

valley, and the submarine valley and canyon of Hudson River. The conclusion is reached that 

the Sound is in no way related to the submarine channel heading off Sandy Hook but is the 

result of eastward-draining streams. The cutting of the Hudson channels -is referred to Pleistoce!le rather than to Tertiary time. A table -in which the points of interest are arranged g~ographically is provided to aid those who may have opportunities for field examinations in the 

region. 

The Pleistocene deposits of Long Island are unusually complicated-their variations from 

point to point, the existence of great unconformities at several horizons, and the gen_eral s1milarity of m_any of the beds of different ages all combining to render the decipherment of. their 

history a work of great difficulty. No complete section is found at any one point, and in order 

to establish the entire sequence it is necessary to patch together fragments of evidence from many 

scattered localities. The main events of the geologic history, however, seem to be clear, and 

inasmuch as they have been corroborated at many places in New England they may be regarded 

as established. Mistakes in details are inevitable in so complicated a region, and no doubt in 

the earlier parts of the investigation many things escaped observation which, if the work were 

to be done over with the main events of the history as now established in mind, could not f~!t 
22 GEOLOGY OF LONG ISLAND. 

to be noted. Furthermore, to obtain even a large share of the facts accessible would require, 

as on Gardiners Island, weeks of study where only a day or two was available. It is not improbable that on further investigation many new incidents will come to light, and the history of 

the island will prove to be more varied in detail' than is here outlined. 

PHYSIOGRAPHY. 

SIGNIFICANCE OF TOPOGRAPHY. 

There are few places in which so intimate a relation between topography and geology exists 

as on Long Island. . The ·:more conspicuous physiographic features, such as the plateaus of the 

north side of the island, the ridges constituting the so-called backbone, and the gently sloping 

FIGURE 3.-M:anhasset plateau and the superimposed moraine as seen from Long Island Sound. 

plains of the south side, to 

say nothing of· the forn1 of 

the island itself, are all of 

constructional origin. or the 

result of structure developed 

.by geologic forces. In many 

parts of the ~land, espe- · 

cially in the southern half, 

the topography furnishes the 

clue for the recognition of 

many deposits whose composition,_ texture, or structure gives no help in differentiation. In fact, with the exception of the bluff studies and the collection of well records, the examination of the region 

was nece~sarily made mainly from the physiographer's standpoint, and a large part of the 

conclusions as to the deposits of the interior of the island. are based on physiographic evidence. 

Thus one ·approaching the north shore from the water anywhere west of Port Jefferson sees 

before him a high plateau stretching back inland with an apparently level surface, upon which 

a number of miles from the shore a high ridge rises abruptly 100 to 150 ·feet or more above the 

plateau· surface (fig. 3). A close inspection of ·the plateau shows it to be an accun1ulation of 

stratified materials, and a glance at the ridge shows its morainal character. We have, then, 

one great formation (the moraine), with another (the plateau gravels) underlying or ba~ked up 

against it, but which of the two possible relations actually exists seems at first sight difficult to 

" . s 

determine from the topography 

alm~e. After crossing the mo- N 

raine one passes out upon a 

broad plain (fig. 4, c) everywhere g~ntly sloping southward from its highest edge 

next to the morainal ridge 

FIGURE 4.-North-south profile of Long Island. a, Manhasset plateau; b, Harbor Hill moraine; 

c, outwash from ice along Harbor Bill moraine; d, Manhasset surface; e, Ronkonkoma moraine; /, outwash from ice along Ronkonkoma moraine; g, Manhasset ridge projecting above 

outwash. 

and at once identified from its contour as an outwash formation contemporaneous with the 

moraine. A few miles south of the moraine, however, irregularities commonly begin to appear. 

Mounds, low ridges, and even broad, flat-topped plateau remnants emerge above the sloping 

surf~ce and stand with their summits at elevations approaching more or less closely that of the 

plateau north of the moraine (fig. 4, d). A study of the erosion features of both the northern 

and southern parts of the plateau surface shows that it has an erosion topography far more 

advanced than that of the moraine or other Wisconsin deposits, the work done on it being 25 to 

50 or more times that which has b~en accomplished since the deposition of the later drift. From 

topography alone, therefore, without the evidence of sections, it is obvious that the moraine is the 

later and rests upon an eroded plateau (Manhasset). , 

Farther south another ridge, likewise shown· by its topography to be a moraine, rises above 

the older surface and is bordered by a second outwash, through which the plateau surface projects as it does through the northern outwash (fig. 4,j, g). . The outer moraine also, together with 

the adjacent outwash, is therefore younger than and rests upon the eroded Manhasset forma-
P~YSIOGRAPHY, . 23 

tion. That the outer moraine is older than the inner is proved topographically by the fact that 

it· is crossed· by and buried beneath the inner moraine from the vicinity of Manhasset Bay 

westward. 

The morainal ridges are not the only elevations rising above the Manhasset surface. The 

hills near Wheatley and the Mannetto Hills· stand 100 feet above the Manhasset, and a glance 

at their contours as shown by the topographic map is sufficient to suggest that their origin 

is other than morainal. The general ·-form of the hills near Wheatley, for mstance, suggests erosion rather than accumulation~::--.· Because of this fact a careful search was made for 

exposures of older material beneath the surface mantle of.drift, resulting in the discovery of a 

core of 1nuch older highly stained, deeply weathered Mannetto gravel. The topography of the 

Mannetto I-Iills similarly indicates a formation much older th~n the Manhasset, for although 

the Manhasset is deeply cut by erosion the plateau character of its surface is still apparent 

through practically its entire extent, but only an isolated and much-eroded remnant of the 

Mannetto plateau remains. 

The topography alone, therefore, affords evidence of the existence of three great Pleistocene 

deposits separated by erosion intervals of great lengths-(1) the :Mannetto gravel followed by 

the post-Mannetto erosion, (2) the Manhasset formation, after which came the Vineyard erosion, 

and (3) the Wisconsin drift. The well records and cliff'sections fill in the gaps, showing theJameco 

gravel, Gardiners clay, and Jacob sand between the :Mannetto and Manhasset formations, and the 

IIerod gravel, :Montauk till, and Hempstead gravel members of the Manhasset. The topography 

is the key not only to the Inajor incidents of the geologic history of the island but to many of the 

minor incidents as well, affording a clue to the origin of aii aln1ost infinite number of the subordinate features of the Mannetto, Manhasset, moraine, and outwash s_urfaces. 

GENERAL ·E'EATURE S. 

Long Island is long and narrow and in.outline bears more or less resemblance to a fish or 

whale, a similarity early recognized by the maritime inhabitants, who, in carrying out the conceit~ designated the ridge traversing the island lengthwise the backbone and the long points 

terminating the island at the east end the north and south flukes. 

- The broad end of the island, or the "head,'; is separated from Manhattan Island, the site of 

the oldest part of the city of New York, by East River, -the narrow channel connecting New York 

I-Iarbor with Long Island Sound. This channel is cut in rock, ledges of gneiss appearing on both 

banks, and is less than half a mile in width.· On the northeast, however, it broadens rapidly, 

1nerging into Long Island Sound, from 5 to 20 miles wide, which lies between Long Island and 

the Connecticut shore. · 

Long Island presents a bold face toward the So-qnd, bluffs from 30 to 100 feet in height 

extending, with a few slight interruptions, through·'its. entire length. West of Port Jefferson a 

well-nlarked though somewhat irregular plateau stretches southward from the tops of the bluffs 

for 1 to 7 miles at an altitude commonly from 100· to. 200 feet·. -Along the southern limit of -the 

plateau in the western half of the island and capping the biuffs along the north shore in the 

eastern half to· Orient Point at the end of the North Fluke stretches the northern of the two 

morainal ridges that traverse the island (fig. 4), rismg in places as high as 200 feet above the 

plateau, or 391 feet above the sea. A little south of Manhasset Bay a second ridge branches from 

the first. It is low and is interrupted at the west end but gradually rises eastward, reaching 

a height of about 410 feet at High Hill, south of; Huntington. Thence it continues eastward 

as a strong ridge nearly paralleling the first but With ·some interruptions and terminates on th~ 

- South Fluke at Montauk Point. Between the two ridges are extensive areas of sand and fine 

gravel, some being gently sloping outwash plains of sands, others.plains pitted with deep, bowllike depressions or valleys, and still others undulating hills of sand or gravel or flat-topped 

. plateau remnants. South of the southern ridge~th'e vast outwash plain of fine gravel and sand 

already mentioned stretches southward for 1 to 11 miles·to the sea. This plain is characterized 

by many well-marked, though streamless, channels, and by low swells here and there, projecting slightly above the general surface. .Besides the morainal ridges described there are near 

,.J, 
24 GEOLOGY OF LONG ISLAND. 

Wheatley and south of Huntington Inassive hills of irregular outline, some extending well to the 

gouth of the northern ridge. These are the Westbury, Mannetto, Half Hollow, and Dix hills, 

which are, as is explained elsewhere, different in age' and origin from the ridges. 

Off the south shore of the island is along, more or less disconnected barrier beach inclosing 

the broad but shallow Jamaica; Great South, Moriches, and Shinnecock bays and the great salt 

marshes between Coney Island and Babylon. Along the north shore lesser bars, beaches, and 

spits connect small islets with the main island or project into the numerous harbors and bays 

or into the Sound. In fact, these beaches have now joined with the main body (Long Island) 

what must originally have been about 15 distinct islands. 

Although old channels abound on the island few have streams now flowing in them, and 

most of these are of small size. At Sn1ithtown, on the north side, at Riverhead, between the 

two flukes, and near Yaphank and Great River stations on the south side are deeper channels 

that cut the water table farther from the coast than the others; hence the strean1s flowing in them 

are of greater volume.· 

FORM OF THE ISLAND. 

AGENCIES INVOLVED. 

Long Island is the resultant of opposed agencies of deposition and erosion. Marine currents, ice, and glacial streams have each played a part in both the upbuilding and the tearing 

down of the island. That the deposits now. above sea level are small compared to those once 

existing in the region there is probably little doubt, indicating that since Cretaceous time erosion has on the whole predominated over deposition. Although erosion is not now going on 

very rapidly,· the amount to be removed before the island is reduced to sea level is far less than 

that removed in the past, aJ?.d if conditions remain unchanged the time n1ay yet come when the 

island shall cease to exist. Notwithstanding the preponderance of erosion, however, the present 

·form of the island is due to donstructional rather than to destructional agencies. 

EAST RIVER. 

The northern part of the shore line of the west end of Long Island is determined by East 

River, a tidal channel connecting New York Harbor with Long Island Sound and separating 

Long Island from Manhattan Island. -The southern part of East River occupies a channel cut in 

rock and the northern part meanders through deposits of drift. This chaiinel has been discussed 

by a number of writers. S. L. Mitchill 1 urged that Long Island must have been recently separated from the mainland by the encroachment of salt water. John Bryson 2 referred its origin 

to the erosive action of the escaping waters of subglacial streams. F. J. H. Merrill 3 suggested 

that the rock channel was probably due to the solution of a belt of limestone. J. B. Woodworth 4 

thought the escape of ponded glacial waters d~ing the final ice retreat had something to do 

with the shaping of the channel in the drift. Bailey Willis and R. E. Dodge 5 regarded it as 

occupied by a tributary of the Hudson at the time of the excavation of the submarine channel. 

W. II. Hobbs 6 presented ·sections showing the general absence of limestone and proposed faulting 

and jointing as the explanation of the form of the rock channel. A. C. Veatch 7 made it the 

site of a tributary of the Hudson in the post-Miocene erosion interval. 

The present writer regards the rock channel to be due to mechanical erosion by streams 

rather than to solution, as there seems to be too little limestone in the area to account for its 

size or its configuration. Its form was most likely controlled by joints (or possibly fault planes) 

or by the strike of the beds, with which the channel agrees closely in direction. It is not believed 

J Med. Repository, vol. 3, 1800, p. 329. 

2 Geol. Mag., new ser., vol. 10, 1883, pp. 169-171. 

a Annals New York Acad. Sci., vol. 12, 1900, pp. 113-116. 

• Bull. New York State Mus. No. 48, 1901, p. 658. 

5 New York City folio (No. 83), Geol. Atlas U.S., U.S. Geol. Survey, 1902. 

a Bull. Geol. Soc. America, vol. 16, 1905, pp. 151-182; The configuration of the rock floor of Greater New York: Bull. U. S. Geol. Survey No. 

270, 1905. 

7 Underground water resources of Long Island: Prof. Paper U. S. Geol. Survey No. 44, 1906, Pl. VI. 
PHYSIOGRAPHY. 25· 

that the present depression is due in any material degree to actual downfaulting. The northern 

part of the channel seems to have been cut subsequent to the period of the Manhasset accumulation, for the deposit~ of this formation, as shown by their remnants, undoubtedly overlapped 

upon the mainland. The channel was completed before the Wisconsin ice advance, but· the 

escaping waters from this retreating ice sheet and the subsequent tidal scour probably did 

much to clear out the deposits left ~y the last glacier. The stream that excavated the rock 

channel seems to have .been a short one, having no connecti9n with the depression in which 

the Sound lies. 

NORTH SHORE SCARP. 

From a point near the west end of the island eastward to Orient Point, Long Island Sound 

is almost everywhere faced by a steep scarp, rising in places more than 100 feet above the water. 

Superficially it is plainly of erosional origin, having the form of more or. less fresh bluffs and 

cliffs (p. 54). In reality,. however,_ erosion has done little more than cut a narrow shelf into 

the land mass and wear away a few projecting points. 

The.history of the scarp is both long and complicated. The beginning of a scarp along the 

north side of Long Island dates back before the Pleistocene, to the time when the Tertiary 

streams were begin;ning to excavate the Sound Valley. The direction of the streams and the 

strike of the beds make it seem probable that even then a somewhat steep slope existed not 

far fron1 the line of the present north coast-a slope which, though deeply buried, is still tracenble in places by well borings. It seems likely that in the succeeding early Pleistocene stage 

(Mannetto) the ice margin rested along the erosional slope already formed, producing on its 

retreat a steep ice-contact slope that rose at least 3.50 feet above the present sea level. In the 

post-Mannetto stage, however, the active erosion, though deepening the Sound, everywhere 

FIGURE 5.-Relati<ms of Cretaceous, Mannetto, Manhasset, and present north-shore 

scarps. 

attacked the scarp, with the result 

that it was nearly or completely ob-

. !iterated in eastern Long Island, and 

toward the west end only a few remnants persisted at the terminations of 

projecting spurs of the old mass. 

Such appear to have been the conditions at the advent of the Jameco 

ice, which not only failed to add to the scarp but actually reduced its height by adding to the 

filling of the Sound Valley, a process that was continued through theGardiners and Jacob stages. 

During the Manhasset invasion; on the other hand, the conditions seem to have been more like 

those of the Mailnetto, and although the ice at times advanced much farther south the margin 

seems to have rested along the north side of the island for considerable periods, during which 

the thick Manhasset formation, rising in places to a height of 200 feet above the present sea 

level, was built up. At the same time the weight of the ice in the Sound region and its drag 

or shove on the land combined to produce a notable folding that helped to intensify the scarp, 

which was eventually left in the shape of an ice-contact slope on the retreat of the ice. The 

scarp was afterward notched by the streams of the Vineyard interval of erosion, subdued and 

rounded by the Wisconsin ice, and cut by the waves of the present Sound until finally it reached 

its present form. The amount of the late wave erosion is considered in the discussion of the 

bluffs (p. 54). The present conditions along the north shore in the western part of the island 

nre represented in figure 5, which brings out the buried Cretaceous and Mannetto scarps beneath 

the :Manhasset. 

HARBORS OF THE NORTH SHORE. 

The north coast along the western half of the island from Port Jefferson to New York 

is ind.ented by a series of harbors, including Flushing Bay, Little Neck Bay, Manhasset Bay, 

Ifempstead Harbor, Oyster Bay Harbor, Cold Spring Harbor, Huntington Harbor, Centerport 

I-Iarbor, Northport Harbor, Nissequogue Inlet, Stony Brook Harbor, and Port Jefferson Harbor. 

These harbors range in length from about 2 ·miles (Northpor~ and Centerport harbors, etc.) 
26 GEOLOGY OF LONG ISLAND. 

to about 5 miles (Hempstead Harbor, etc.), and their axes, with one or two exceptions, are 

straight or gently curving. Each one is bordered by slopes rising somewhat steeply to ~n 

altitude usually of 100 to 200 ·feet. Some of the indentations, as Port Jefferson, Stony 

Brook, Northport, and Huntington harbors, end rather abruptly in amphitheater-like 

terminations, but most of them extend inland for a number of miles beyond the limit reached 

by the sea, gradually closing in to V -shaped terminations. The valleys are generally free fi·om 

conspicuous branching such as would be expected if they had been produced by the ordinary 

process of stream erosion. There are, however, on the borders of each main valley many 

small lateral valleys sloping toward the· harbors, which, although more or less filled with late 

drift, are distinctly recognizable. At Smithtown, where little late ·drift is present, a typical 

dendritic drainage system is seen. (See topographic map, Pl. II, in pocket.) Like the others, 

it is of pre-Wisconsin origin, as shown by glacial deposits, including an esker in the bottom 

of the main valley. · 

The bluffs bordering the harbors con.si.st as a rule of Manhasset materials, but well borings 

and outcrops along the shores indicate that the necks between the harbors have Cretaceous 

cores rising high above sea level. In other words, the present valleys, although generally cut 

in the glacial gravels of the Manhasset formation, are coincident in location with older Cretaceous 

valleys. · 

·Much material bearing on the formation of the north shore harbors and valleys has been 

published. W. W. Mather 1 noted the action of springs in converting sand into quicksand so 

that large masses flowed from the bluffs. Elias Lewis, jr./ also pointed out that many valleys 

are due to spring sapping, but he held that the harbors were formed by erosion by subglacial 

streams. Warren Upham 3 referred the Smithtown drainage system ·to stream erosion. 

John Bryson 4 followed Lewis in referring 

the excavation of the harbors to subglacial <~1> 

....... ~ · streams. F~ J. ·H. Merrill 5 considered the 

"' .. fl.~ harbors to have been "plowed out by project-

-~~--------·---- ing spurs of ice" and regarded the adjacent 

FIGURE 6.-Relation between the original and the present cross section of elevations as due to ice thrust. Arthur Hoinorth-shore valleys. lick 6 and W. 0. Crosby 7 agreed with Merrill. 

J. B. Woodworth 8 distinctly recognized the stream origin of the valleys, although stating that 

they had been modified, enlarged, and deepened by the action of the Wisconsin ice. A. C. 

Veatch 9 brought out the fact tha~ the present harbors, though not cut in Cretaceous formation!', nevertheless coincide in location with buried Cretaceous valleys cut in pre-Jameco time. 

The coincidence ·of location he explained as due to the concentration of underground waters in 

the old depressions, giving rise to extensive spring sapping. Some modification by the Wisconsin ice was recognized. The present writer agrees with Veatch, but would lay more 

emphasis on "ice erosion," for the valleys, except the one at Smithtown, are much too broad 

in proportion to their length and terminate too bluntly to be characteristic of stream action. 

The trunk valleys are also larger in proportion to ~he lateral channels than is called for by 

normal stream erosion. Drift deposition (Wisconsin) has also obscured and obliterated many 

of the old valleys, as at Lloyd· Neck and in the region south of Huntington. The erosion is 

regarded as the work of the basal part of the main ice she~t rather than the projecting lobes, 

as was asserted b:r some of the earlier writers. The conditions are illustrated by figure 6. 

1 Geology of New York, pt. 1, 1843, p. 32. 

2 Am. Jour. Sci., 3d ser., vol. 13, 1877, pp. 142-146. 

a Idem, vol. 18, 1879, p. 201. · 

4The geological formation of Long Island, New York, 1885. 

6Annals New York Acad. Sci., vol. 3, 1886, pp. 341-364. 

Trans; New York Acad. Sci., vol. 14, 1895, pp. 8-20. 

7 Tech. Quart., vol. 13, 1900, p. 105. 

s Bull. New York State Mus. No. 48, 1901, p. 636. 

9 Underground water resources of Long Island, New York: Prof. Paper U. S. Geol. Survey No. 44, 1906, pp. 43-44. 
PHYSIOGRAPHY! 27 

SHORE LINE. EAST OF PORT JEFFERSON. 

West of Port Jefferson, as has been seen, the coast is highly irregular, being indented by 

many deep bays and harbors. East of this locality, however, the shore is very regular, being 

made up of long, gently curved reaches with here and there a headland barely projecting from 

the general line. Throughout this stretch the contour of the coast has manifestly resulted 

from the action of the waves and currents of the Sound, its regularity being the direct result 

of its fairly uniform composition. For most of the distance the bluffs bordering the shore are 

1nade up of sands and fine gravels, but in places there is. a more resistant bed of till or of clay 

which gives rise to a slight projection in the coast line. An exceptionally high bluff may aJso 

give rise to such a projection, as at Woodhull Landing. The swell at Rocky Point Landing 

is probably due to the presence of the Gardiners clay ill the bluff, the one at I-Ierod Point to 

the Montauk till member of the Manhasset formation, that at Roanoke Point to both clay 

and drift, that at Jacobs Point to the clay, those at Ducks Pond, I-Iorton, Rocky, and Tetry 

points to thick beds of till Ot1ontauk member~), and the one at Mulford Point to the clay. 

West of Port Jefferson the general trend of the coast is somewhat north of east. liere, 

however, the coast makes a decided bend and for 20 n1iles runs due east, beyond which it trends 

somewhat more northerly than at the west end. In these stretches the elevation of the·bluffs 

becomes less, decreasing from 150 -feet near Port Jefferson to 100 feet north of Riverhead and 

to less than 50 feet near Orient Point. It would seem almost as if the coast had been cut back 

through the plateau portion of the :Manhasset formation into the sloping part on the south. 

If so, the original coast, as indicated by the eastward prolongation of a line along the Manhasset 

crest, nu1st have been 5 miles or more north of its present pos~tion. 0{ this, however, there is 

no very definite evidence. A chart of the Sound shows no notable shoals such as should exist 

if the land had been thus cut back. In fact, the only shallow places are off Woodhull Landing 

and I-Ierod,. Roanoke, and Ilorton points and between Rocky and Terry points. Those at the 

first three localities are spitlike projections; those at th~ last two have the form of offs1;wre 

shoals. None is situated n1ore than about 1} miles offshore. Elsewhere the bottom of the 

Sound is aln1ost perfectly flat and affords little evidence of extensive erosion. 

On turning to the island, however, it is found that, notwithstanding there has been no 

greater deposition of the late drift in the eastern part than at points farther west and no more 

. opportunity for obscuring the old topog~·aphy, large northward-draining valleys similar to 

those west of Port Jefferson are entirely absent. If such valleys ever existed, and there seems 

to be no reason why they shOltld not have be~n formed here as we1l as farther west, they must 

have been obliterated by subsequent erosion of the coast line. 

It is an interesting fact in this connection that the deep Sound channel, described elsewhere 

(p. 56), follows the coast of this part of the island at a distance of ab_out 4 miles. It is probable 

that the land, if it ever extended much farther northward, did not reach beyond the line of 

this channel. On the whole it seems likely that the coast in this region has been cut back for 

several miles, but if so most of the erosion occurred in pre-Wisconsin time, possibly in a period 

of relative submergence that followed the cutting of the Sound and Peconic Bay channels, 

such as is assumed in the discussion of the shaping of the shores and islands of Peconic Bay. 

The post-Wisconsin cutting is not believed to have. exceeded half a mile. 

PECONIC AND GARDINERS BAYS. 

No single feature of the outlin,e of the island is more conspicuous than the great connecting 

bays lying between the North and South flukes. (See topographic map, Pl. II, in pocket.) 

Together these bays form a water body increasing in width from a few yards at .the mouth of 

Peconic River to 14 miles near Garcliners Island, 27 miles farther east. The water body does not 

increase uniformly in width throughout and is much broken by islands,· the largest of which are 

Shelter and Robins islands, and by projecting necks mostly connected with the n1ainland by 

beaches, an1ong which are Jessup and Hog necks, near Sag Harbor, on the south side, and Little 

and Great I-Iog necks, in Southold, on the north side. These islands and necks all stand fron1 
28 GEOLOGY OF LONG ISLAND. 

50 to 100 feet or more above the present sea level and appear to be remnants of old land surfaces a.t thes~. elevations. Their topography, as well as that of the part of the main island 

adjoining the bays, seems to be in part constructional and in part dqe to stream erosion, 

although greatly modified and obscured by the subsequent passage of ice sheets over its surface. 

The contours of the shores, howeYer, are due almost wholly to the action of currents and waves. 

J. D. Dana. 1 advanced the view that the Connecticut and other Sound drainage passed 

southward across the· North Fluke in the vicinity of Mattituck into Peconic Bay, but what 

course it then took he did not state. Three years later John Bryson 2 suggested that the further 

course of this stream (which he assumed to .have been subglacial) was through the depression 

at Canoe Place, and stated his belief that Block Island Sound and Gardiners and Great and 

Little Peconic bays are the result of subglacial stream erosion. ' 

The drainage immediately preceding the last ice invasion was toward the chain of bays 

from all directions. Peconic River entered from the west, as a.t present. Along the North 

Fluke traces of pre-Wisconsin valleys·leading southward ma.y be seen at a number of points. 

Mattituck Inlet, although now opening into the Sound, then took the drainage southward, as is 

indicated by the marked convergence of the lateral valleys in that direction; but that it was not 

the outlet of Connecticut River nor of any other stream of the mainland or Sound, as was stated 

by Dana, is shown conclusively by its shallowness, narrowness, and the character of the tributary channels _mentioned, which indicate that it formed the headwater portion of a minor 

drainage system rather than the outlet of a large river. (See Pl. XI, 0, p. 52.) On the South 

Fluke, Sebonac Creek near Shinnecock, the Long Pond and Northwest Creek valleys near Sag 

Harbor, and Threemile Harbor, are valleys produced by northward drainage. · 

The course of the trunk stream receiving this drainage can not be located with any certainty. The bottoms of the bays are irregular and do not appear to· contain any submerged 

channels. The deepest water at the present time is along the south side of Great Peconic Bay, 

off the points of Robins Island and Little and Great Hog necks, and between Shelter Island 

and the North Fluke, and this line may mark the course of the old drainage. It could ha;rdly 

have passed outward at Canoe Place, for the gap in the Manhasset at this point is only a few 

hundred feet wide, nor through the shallow and circuitous passage south of Shelter Island. 

All that can be Gl.efinitely stated is that in the stage immediately preceding the last ice 

advance Peconic River flowed essentially in its present course, that the drainage entered the 

Peconic trough both from the north and the south, and that the waters passed eastward into 

the ocean. The land at this time stood at least 150 feet higher than at present, as indicated 

by the submarine channel east of Montauk (p. 60), but a submergence took place and much 

marine erosion, marked by a shaping of the shores and a separation of the islands, occurred before 

the advance of the Wisconsin ice. The ice, although modifying the topography in many ways, 

probably did not materially alter the main features. Postglacial erosion has .likewise done 

little except to -modify the contours of the shores. 

Although the Peconic region was the site of a drainage system just before the Wisconsin 

ice invasion, it is doubtful if the depression owes its origin to stream erosion at that time. More 

probably the basins are largely the result of nondeposition in Manhasset tin1e because of thejr 

occupation by ice masses around which the materials of the various necks and islands accumulated. If such was the case, it is not ·unlikely that .incipient depressions favorable to the 

retention of the ice masses were early formed through differential compacting of the underlying materials by the weight of the ice sheet, through ice scouring, or through the uplift of 

the North and South flukes by the dynamic action of the ice. 

OUTLINE OF THE SOUTH SHORE. 

If the extension of the land produced .in postglacial time by the formation of marsh 

deposits along .t.he old shore is left out of account, the south coast of Long Island in its broader 

aspects consists of a number of broad, gently curving, lobelike projections of sands or fine gravels. 

1 Am. Jour. Sci., 3d ser., vol. 40, 1890, pp. 425-437. 2 Am. Geologist, vol. 12, 1893, pp. 402-403. 
U.S.GEOLOGICAL SURVEY PROFESSIONAL PAPER 82 PLATE Ill 

TOPOGRAPHIC MAP OF MANNETTO HILLS REGION, LONG ISLAND, NEW YORK 

Scale a2;oo 

les~=c~~~z=e~~=Eo==============~J=============~ldiles Contour interval 20 £eet. _Da;hHn is Tnea:r~ eea; level-. 

1913 
PHYSIOGRAPHY. 29 

A smnll but strongly curved lobe extends between New York Harbor and Jamaica Bay. East 

of this bay is the broad, flat lobate curve extending to South Oyster Bay, a distance of about 

20 miles. The next lobe, which is of similar character, extends between Mas~apequa and 

. Babylon; another still smaller lobe extends between Babylon and Bayshore. Beyond this 

point the shore is .more broken and complex, but the general lobate character is visible as far 

east as Southampton. Between the lobes and also cutting their margins nearly every half n1ile 

are small estuaries a mile or so long and· n quarter to half n 1nile wide or estuary-like valleys 

now occupied by marshes. Some of these depressions are traversed by streams and ·others 

are dry. 

The lobes appear to have been formed by the deposition of materials carried out from 

glaciers by glacial streams during the. melting of the ice. W ~st of Bayshore the lobes are 

regular in outline and appear to owe their form largely to outwash from the last or Wisconsin 

ice sheet at a time when the land stood nearly at its present level. Farther east they are less 

regular, are cut by deep channels and bays, and h.ck to a·considerable extent the even surface 

characteristic of the western lobes. It seems probable that the lobes are due primarily to 

deposition during an earlier ice advance, and that they were afterward subjected to erosion 

and finally to partial burial by the less copious outwash during the Wisconsin invasion. 

The coast from Southampton nearly to Montauk Point follows a nearly straight line intersecting old headlands arid crossing old bays. It is in part due to erosion and in part to deposition .. In the vicinity of Southampton the land probably at one time extended half a mile to 

a mile or more farther seaward than at present. Southeast of Bridgehampton it possibly 

extended half a mile farther, at Apaquogue about the same, and between Easthampton and 

Amagansett a mile or more. That the shore at Montauk has retreated considerably is unquestionable. The Montauk shoals, which lie about 2 miles south of the present shore, indicate 

that the land probably once extended to that point.. Much of the erosion may have occurred 

before the Wisconsin ice advance, and the amount of cutting back in post-Wisconsin time.may 

be not over a mile and possibly less, although, as pointed out by W. W. Mather,t not less than 

2 acres is lost annually by erosion in this region. · 

The same waves and shore currents that truncated the headlands formed beaches, connecting 

the projecting points and inclosing the so-called bays and ponds, most of which occupied old 

drainage channels in the gravels. Some of the bays are still connected with the ocean by narrow 

channels, but in most places the beaches are unbroken. The most important beach is N apeague 

Beach, lying between Amagansett and Montauk Point, which has a length of 4 miles and a width 

of 1! miles. The sands of the beaches have for the most p~:r:t come from the erosion of the land 

at the points mentioned, and the material not so used has been transported westward to the great 

barrier beach describecl'under Recent deposits (pp. 177-178). 

SURF ACE LINEAMENTS. 

INFLUENCE OF THE CRETACEOUS. 

The Cretaceous of Long Island is extensively developed, as brought out in the bluffs of 

the north coast, where natural exposures are numerous, and in clay pits and wells in the interior. 

As it comes to the ~urface at few places in the island, it has little or no direct influence 

on the topography, the only possible exception that was noted being at High Hill, southwest 

of Ifuntington (Pl. III), where the character of the drift suggests that the core of this high 

knob may be Cretaceous, a supposition rendered not improbable by the finding of Cretaceous 

material in a near-by well (No. 586, p. 84) at an elevation of over 300 feet. Although not 

directly controlling the present topography, the Cretaceous core has nevertheless exerted a very 

extended indirect influence upon it through control of the :Ma.nnetto deposition, which took place 

over and around the Cretaceous remnants. · 

1 Second Ann. H.ept. New York Geol. Survey, 1838, p. 126. 
30 GEOLOGY OF LONG ISLAND. 

M:ANNETTO REMNANTS. 

Mannetto plateau.-At only one point on Long Island; so far as is known, is any trace of the 

original :Mannetto surface left. Beginning a little south of the peak lmown as High Hill, near 

the north end of the Mannetto Hills, and continuing southward to a point about hal{ a mile. 

north of Bethpage, a. distance of about 3 miles, is a narrow plateau, one-fourth to one-half a 

mile wide, constituting the flat crest of the hills (Pl. III). It ranges in altitude from about 330 

feet at the north end to 270 feet at the south end and is believed to be a part of the original 

~1annetto surface. Whether the slope is original or is due to differential tilting is not known, 

but the writer is inclined to consider it original. · 

Hills of Mannetto gravel.~Outside of the Mannetto Hills the l\1annetto gravel is commonly represented only by irregular hills, although traces of the plateau level are observable in the Dix Hills. In general, however, erosion has reduced this mass to a series of radiating 

spurs.· Near Wheatley the erosion is even more advanced, and nothing but an irregular group 

of hills remains, as shown by Plate VI, D (p. 32) and the description on page 82. Similar but 

more isolated masses of the Mannetto grav~l are believed, ·from the character of the overlying 

drift, to control largely the 

topography at I-Iarbor Hill, 

at Roslyn, and in the knobs 

rising above the :Manhasset 

surface on Manhasset Neck 

(p. 82 and Pl. IV). 

MANHASSET SURFACE. 

11 i g her platewus.-The . 

Manhasset surface shows considerable diversity of contour, 

both original and subsequent 

forms being extensively represented in it, the former by 

the great plateaus and the 

latter by the deep valleys ariel 

sharp bluffs. The plateaus, 

although recognized by few 

of the earlier writers, principally-because of the till coat-

+.~ ? f ' ~· t ~Milee · ing .and the. semimorainal 

FIGURE 7.-Sketch showing location of the upper and lower Manhasset plateaus from Douglas- aspect of the SUrface, become, 

ton to Oyster Bay. when the physiography of the 

island· is studied in detail, one of the n1ost conspicuous and important of its topographic 

features~ Although they are spoken of as plateaus it must not be thought that the surface of 

.the Manha·sset formation is continuous or perfectly flat for any great distance. As a matter 

of fact, the plateau is deeply indented or even separated into detached parts by the deep bays 

a:Od harbors, some of which extend back nearly or quite to the moraine, and is almost everywhere deeply trenched by stream valleys and characterized by superficial irregularities clue to 

the deposition of a mantle of morainal outwash or other drift over its surface. The continuity 

of the plateau surface is also broken along the axis of Manhasset Neck by knobs of older material 

projecting to a height of 60 feet or more above the plateau level (Pl. IV). 

The plateaus fall into three belts-the north-shore belt, extending from the vicinity of New 

York to. Orient Point; the Middle Island belt, extending from Rockaway Ridge through Bethpage and IIalf I-Iollow hills, the highlands near Middle island and south of Riverhead, and the 

islands and necks of the north side of Great and Little Peconic bays to Shelter and possibly 

to Gardiners Island; and the South Fluke belt, extending from.its junction with the l\1iddle Island 

belt south of Riverhead eastward along the South Fluke to l\~ontauk. Each of the belts is 
U.S. GEOLOGI.CAL SURVEY PROFESSIONAL PAPER 82 PL.ATE 1 V 

TOPOGRAPHIC MAP OF GREAT AND MANHASSET NECKS, LONG ISLAND, N.Y. 

Scale a2~oo 

l~~~E3t~=cL9~o~~~~~==~ 1==============~2bfi~s Con:tmn· :interval 20 £ect. Da;t-~ is m.ea;n.. sea- levtiL. 

1913 
PHYSIOGRAPHY. 31 

described at length on pages 119-121, and .their characteristics are shown in detail by the topographic map (Pl. II, in pocket). 

Lower plateau or terrace.-A peculiarity of the northern plateau belt in western Long Island· 

is its double character or development at two distjnct levels, as bro.l.lght out by figures 7 and 8 

and by Plate IV. The lower terrace, which lies along the coast, ranges from 1 to 6 miles in 

breadth and has a maximum-elevation of a little over 100 feet; back of this surface and usually 

separated from it by a more or less distinct though gentle scarp lies a higher plateau at 180 to 

200 feet, reaching back to the moraine and beyond. The significance of the lower plateau is 

son1ewhat obscure. The character of its surface and especially 

of the slope between it and the 

higher plateau is somewhat suggestive of wave work. The surroundings at certain points, however, as at Glenwood Landing 

on I-Iempstead Harbor, where 

the terrace is unusually well developed (Pl. VI, A, p. 32), would 

semn to preclude such action, it 

being hardly conceivable that 

the waves of a confined body of 

water hardly more than half a 

1nile wide could have cut back a 

terrace nearly a mile in breadth 

.L.ONG 

1 Vz 0 ·1 2 &Miles ~~--~--~--~--~--~ 

in deposits rising a hundred feet FIGURE 8.-Sketch showing location of the upper and lower Manhasset plateaus in the 

above the water level. Aside Lloyd and Eaton necks region. 

fron1 the fact that this theory wol.lld require a subsidence of at least 100 feet in post-Manhasset 

time, a movement of which there is elsewhere no record, examination shows· that this plateau has 

11 drainage topography fully as far advanced, considering its lower level, as that of the upper 

plateau and indicating equal antiquity. 

The material of the lower plateau is clearly Manhasset and is, at least locally, the :Montauk 

till member of the :Manhasset, extending nearly or quite to sea level and therefore considerably 

below the level of the Montauk member in the gravel pits farther south on Hempstead Harbor, 

the ·conditions being similar to those shown in the generalized north-south section in figure 9. 

The explanation that the writer regards as most probable is that which assumes the lo";er 

plateau or terrace to be an original feature formed in connection with the Montauk ice invasion. 

· On the first approach of the ice the margin probably lay 

in the Sound not far north of the present coast line (fig. 

9, a), and in front of it the Herod gravel member of the 

1Y1anhasset formation was laid down. On the actual in- FIGuRE 9.-Stction showing relations of Manhasset pia- Vasion Of the reo-ion the ice reached SOmewhat farther tea us and deposits along the north shore in western Long b~ 

Island. a, Presentblufiscarpat coast; b, modified ice- south, passing over the Herod gravel member at least to 

contactscarpbetweenhighandlowManhassetplateaus. the head of Hempstead I-Iarbor, as indicateq. by the 

bowlder bed capping the gravel. On its recession or on its sl.lbsequent readvance its margin 

rested along the line now marked by the scarp separating the low plateau from the high plateau 

(fig. 9; b), and in f:ront of it were laid down' the ·higher gravels (Hempstead member of ManhassE:t formation). This sequence of events explains the presence of the :Montauk till member near 

the surface and the general absence of the I-Iempstead gravel member along the coast, the lobate 

forn1 of the landward edge of the lower plateau, the similar erosion features of the two plateaus, 

the nature of the separating scarp (ice contact),_ the peculiar position of the terrace at Glenwood 

Landing (due to an ice tongue in I-Iempstead Harbor), and the greater disturbance exillbited 

by the material of the lower plateau (d-qe to more prolonged shove and drag by th~ ice). 
32 GEOLOGY OF LONG ISLAND. 

MORAINES. 

MORAINES OF STRATIFIED DRIFT. 

EXTENT A,ND GENERAL CHARACTER. 

The moraines of Long Island have in. the past been almost invariably regarded as the culminating physiographic members of the region, and althoug4 later work: shows them to be 

subordinate to the l\1anhasset they are nevertheless striking features of the topography (Pl. 

V, .A), rising in 1nany places 100 to 150 feet above the surrounding level and reaching a maximum 

elevation of 410 feet above the sea. They are also of notable extent, stretching the entire 

length of the island without any considerable break. Topographically they may still be considered as constituting the "backbone" of the island, but it should be borne in mind that this 

is a superficial and not a structural relation, 

·~ ~ ~ :t~:: t~:~~a:::: :r!:i/~1~:f;:s~= ing on the Manhasset surface. FIGURE 10.-Section showing mode of formation and profiles of morainal 

cones. a, Point of emergence of feeder; b, steep debris fan; c, isolated cone The moraines show great diversity in 

of regular contour; d, irregular cone; e, confiuent cones; k, kettle. form from point to point according to the 

nature of the material composing them and the co:o.ditions of its deposition, nearly all the common types of morainal accumulations being represented. They are despribed in detail in the 

section on stratigraphic geology (pp. 163, 168), and it is necessary to consider here only the 

special types and minor features of the morainal deposits. 

MORAINAL CONES. 

Isolated cones.-The isolated morainal cones represent one of the simplest forms of morainal 

accumulation, seemingly being the result of deposition by waters issuing from the ice front at 

a single point and at a considerable elevation above the base (fig. 10, a). The volume of the 

feeder must of necessity be very small and incapable of transporting material far beyond the limits 

of the confined ice channel, for a larger volume would soon cut down. to the base of the ice and 

form a normal outwash channel. Both the character of the deposition and the elevated position of the feeding channels, therefore, 

Point to ~mall rivulets as the source of c d 

material of the morainal cones. When ~ 

a- / ..::._" ....______, ~ .............._ . / -

____... ~ ""-..... ~---=~~----------------~~~----------~ 

first formed the deposits had the form of FIGURE H.-Profiles of morainal cones. a, Isolated cone; b, semicone; c, confiua steep fan or semicone (fig. 10, b), but on ent cones of similar magnitude; d, confluent cones of various sizes. 

the retreat of the glacier the part lying 

next to the ice was let down and a more or less irregular cone resulted. Some of the cones are 

rounded and have fairly regular slopes (fig. 10, c). Kettles may occur in any part of the cones but 

are most likely to be found near the margins (fig. 10, k). Considerable till is likely to be present 

on the ice-contact face. · 

A cone completely isolated fTmn the surrounding moraine (fig. 10, c) is not often seen. The· 

best apparent examples are found at High Hill, at the north end of the Mannetto Hills, and in 

the unnamed hill immediately west of this point (Pl. III, p. 28). Both of these are sharp knobs 

resting directly upon the Mannetto or the Cretaceous plateau, above which. they rise 100 feet, 

and they have practically no connection with adjacent morainal accumulations. It should be 

noted, however, that the knobs mentioned are possibly not entirely morainal and that they ma}7 

contain cores of older n1aterial. 

Confluent cones.-All gradations from the isolated cones that are described above (fig. 11, a) 

through semidetached cones (fig. 11, b) to completely confluent cones (fig. 11, c, d) are represented on the island. Their origin is essentially the same, each knob or cone representing the 

discharge either of a single rivulet or of a number of closely adjacent rivulets. Confluent cones 

result from ·the proximity of the contributory streams, which causes their deposits to in1pinge 

on one another and become united into a ridge in which the component parts are represented 
U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 82 PLATE V 

A . OUTWASH PLAIN FROM ICE ALONG HARBOR HILL MORAINE. 

B. BOWLDERY PART OF HARBOR HILL MORAINE NEAR CREEDMOOR. 
U. S.GEOLOGICAL SURVEY PROFESSIONAL PAPER 82 PLATE VI 

TOPOGRAPHIC FEATURES OF LONG ISLAND, NEW YORK 

Scale e2~oo 

l""'=::E3:::.::e3't'====='o"==============~l.======::::i2 Miles Contour in:terval 20 feet . .Da:tu.Tn, is ~ se.t:t, 1eveb. 

1913 
PHYSIOGRAPHY. 33 

by the severn! knobs. Where the feeders are of essentially the san1e capacity the result is to 

build up a ridge of f~irly uniform height (fig. 11, c), but where they are of unequal transporting 

power the ridge is uneven, with one or more kn9bs representing the chief sources of sediment 

rising high above the others (fig. 11, d) . 

. Examples of confluent cones are so numerous that a list of all those on the island would 

cover many pages; in fa.ct considerable parts of the inner moraine and a large part of the outer 

morai.J?.e are 1nade up of rows or groups of such deposits. One of the best examples of a confluent ridge of fairly uniform height is that southeast of Hauppauge or northeast of Central 

Islip (Pl. VII, A). Bald I-Iill, 4 miles southwest of R~verhead, affords an e~ample of a cone 

rising prominently above its neighbors, (Pl. VI, 0). In fact, Bald Hill approaches the isol~ted 

cones in forn1. MORAINAL RIDGES. 

Simple ridges.-The simplest morainal ridge is that forn1ed by confluent outwash cones 

along a stationary ice margin in the manner outlined in the preceding section. Such ridges have 

a simple cross section, as shown at c, figure 10. The best large-scale example is that mentioned 

as occurring southeast of Hauppauge. , 

Double ridges.-Inasmuch as the_ ice front is seldon1 entirely stationary during the upbuilding of a moraine, there is commonly a tendency to repetition of the ridges. . The simplest form 

of n1oraine resulting fron1 this tendency is a double ridge such as those shown in profile at c 

and din figure 10, ·each ridge consisting of-the confluent cones formed at a give:q. position of the 

ice margin. The best example of a double ridge of this character separated by a flrat outwash 

deposit was noted on the road crossing the moraine half a n1~e southwest of Woodbury or 1! 

1niles southwest of Cold Spring station. 

Compound ridges.-Sin1ple and double ridges are the exception mnong the 1noraines of 

Long Island, as elsewhere, the normal form being a compound ridge of considerable breadth, 

as shown in profile ate in figure 10. The formation of a ridge of this type. differs in no essential 

way from that of the ridges described above, except that the cones composing it are confluent 

with those before and behind them as well as with those at their sides-a result following from 

changes in the position of the ice margin smaller than those givingrise to the double ridges. In 

general compound ridges are the result of deposition during a 1?-un1ber of successive slight 

recessions of the glacial margin. The ice may also have temporarily advanced, overriding 

part of the earlier deposits and disturbing them more or less, thus giving rise to abnorn1al forms 

of relief. Under such conditions 1nany ice blocks would becon1e detached and buried beneath 

the drift, causing on 1nelting ·the nmnero~s_kettles that almost everywhere characterize dep-osits 

of this type. The long-continued presence of the ice favored· the incorporation of considerable 

till both within and on the ice-contact face and the scattering of bowlders over the surface. In 

fact, the conditions were such as to develop a most diversified n1orainal topography-high 

knobs, ridges, and gravel heaps of all shapes and sizes alternating confusedly with 'equally 

irregular basins, troughs,_ and deep, angular kettles. This complexity is_ brought out by the 

'topographic sketch, Plate VI, 0. 

The greater part of the southern moraine is made up of compound ridges of the type 

described. Amo:Q.g the especially characteristic portions may be n1entioned that lying south of 

Peconic River between Manorville and Riverhead, that north of. East Quogue, and that between 

Hampton Park, north of Southampton, and Sag I-Iarbor. 

DEPRESSED MORAINES. 

There is son1e doubt as to the propriety of applying the term "depressed" to moraines, · 

as well as to that of considering the particular form of accumulation which it here denote~ as a 

moraine at all. Yet this form occurs in so many places on the island that some term is needed 

for it, and the one given above was selected as best indicating its n'ature. In brief, the term is 

applied to irregular marginal accumulations d~veloped along the ice front in line with the 

normal morainal ridges but failing to rise above the adjacent outwash. The "depression" is 

1629°-14--4 
34 GEOLOGY OF LONG ISLAND. 

due _rather to the nonaccumulation of morainal material than to an excess of outwash. The 

conditions of its formation are brought out in figure 12. Its ri10de of formation differs from 

that .of the normal stratified moraine chiefly in the size and carrying capacity of the glacial 

streams that formed it, the water issuing in large volumes instead of rivulets and forming broad 

outwash aprons instead of the ordinary cones and ridges. The total accumulations, however, 

are not necessarily greater than those in front of th~ normal moraine. The topography of ·the 

depressed moraine is ordinarily si.rn,ilar to that of the compound ridges, exhibiting the same 

d irregular kettle and knob as-

,./ ...... --~~ .. ,\ pect. In some places, where 

, .. ' ',a the morainal.deposits are thin, 

.

,,/.' 

~ 

... ---.····_,,. ........ --- . ~ h ',,',,"',; · the accumulations have little 

more than blocked the previ- oePREssEo MORAINE ouTwAsH ously ·existing valleys of the 

FIGURE 12.-Section showing relation between depressed moraine and outwash. a, Head of underlying land Surfaces, ancl 

outwash plain; b, exposed part of depressed moraine; c, supposed buried part of depressed many kettles of large size and morain~; d, normal profile of moraine. ' 

great depth remain. · 

The most conspicuous depressed n1oraines along the northern ridge are in. the region east 

of Port Jefferson station, where the kettle valleys above qescribed are also best represented 

(Pl. VII, B). In the southern ridge the depressed moraines are. best seen at the gaps in the 

hills between Yaphank and Shirillecock, although good examples are found near Ronkonkoma, 

farther west, and at several points between. Sag Ilarbor and Easthampton, on the east. In 

some localities the morainal material is scanty and the north edge of the outwash approaches 

the simple ice-contact slope in form. 

TILL MORAINES. 

GENERAJJ FEATURES. 

The topography ·of the moraines of Long Island varies widely according to the character 

of the materials of which the ridges are composed, those made up largely of till differing greatly 

from those composed mainly of stratified material. The presence of till in a moraine indicates 

deposition in direct contact with the ice, partly perhaps beneath its marginal portions, hence 

many such accumulations take on the subdued contours characteristic of formations overridden 

and :r;ounded by glacial ice. Under such conditions the tendency is to form a more or less continuous belt made up of small masses exhibiting something of the ridge form and separated by 

intervening troughs or basins. The ridges are lower and more rounded and have gentler slopes 

. than the stratified moraines, and· the depressions are more' regular an<.rshallower and have less 

steep sides. Another feature of the till moraines is the essentially continuous character of the 

ridges~ gaps such as those found in stratified moraines at many places (where they mark the 

emergence of glacial streams) being relatively rare. Cones and sharp ridges of drift are p~actically unknown. The till type of moraine is best developed in that part of Long Island included 

in Greater New York (Pl. VI, B, p. 32). 

MORAINES DUE TQ ICE SHOVE AND DRAG. 

Little evidence of the competency of ice shove as a cause of morainal accumulation is 

afforded by existing glaciers, the tendency nearly everywhere being for the ice to override a 

mass of material in its path and drag it away little by little instead of pushing it along. At 

times, however, the ice evidently developed a tremendous power to push (pp. 201-207), the 

result of which was the formation of immense folds in the overridden material, some of them 

reaching an elevation of 100 or 150 feet, and the development of num~rous faults, in both of 

which the positions of large masses of material were noticeably shifted. 

This shoving action was most conspicuous during the Montauk ice invasion, but was also 

developed to a considerable extent in the Wi~consin stage, during which the moraines under 
U. s;GEOLOGICAL SURVEY 

\ 

I 

PROFESSIONAL PAPER 82 PLATE V II 

DEPRESSED MORAINE AND OUTWASH NEA.R PORT JEFFERSON 

TOPOGRAPHIC FEATURES OF LONG ISL.M.TD, NEW YORK 

Scale 62~oo 1 2 .Miles 

= Contour inte:rval20 feet. Da.:tr.on i8 7Ttean. Ae<N leveL. 

1913 
U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 82 PLATE VIII 

A. 

B. 

PSEUDOMORAINE (DUNES) NEAR FRIARS HEAD . 

.A. Distant view; B . Section. 
PHYSIOGRAPHY. 35 

discussion were formed. The action was most pronounced where the ice encountered. scarps 

or other marked irregularities of surface, such as projections from hills or_ ridges between valleys, 

especially where the trend of the topographic features was at a considerable angle with the ice 

1novement, as shown in figure·13. Under such conditions the previous topography was in many 

places greatly modified, partly by the shoving of the points, as near A, figure 13, partly by the 

pushing' up of Inaterial in converging valleys, as at B, and partly by the breaking down of divides 

and the dragging of the n1a~erial into the adjacent valley, as at 0. Thus in the figure a ridge 

would cross the valley at A, both sides of the valley would be broken down, a small ridge and 

kettle would be formed at B and a larger one at 0, the result being a topography such as is 

shown in figure 14. These figures show how the ice in passing· over a region of diversified · 

topography changes the surface to the morainal type, consisting of. 

irregular hills and kettles. 

Examples of topography of this type, which is truly morainal, 

inasmuch as there has been an actual movement and redeposition 

of Inaterial, abound on Long Island, being observable at dozens of 

points scattered over the Manhasset plateau north of the main ridge 

of the I-Iarbor Hill 1noraine and especially on Great Neck between 

Ifuntington and Centerport harbors, where there are several driftobstructed valleys. Other good examples are afforded by the Shinnecock. Hills and the hills between N apeague and Fort Pond bays, 

:Montauk. In neither of these localities, how~ver, are the surface 

irregularities due entirely to ice shove, a mantle of dune sand materially altering the surface relief of the Shinnecock if not of the Montauk 

hills. The former were covered with drifting sand hills when visited 

by Timothy Dwight as late as 1822. 

A second type of ridges clue to ice shove but not truly of morainal 

character, although the resulting topography has a decidedly morainal 

FIGURE 13.-Hypothetical drainage 

system in loose gravels before being 

covered by ice. A, B, C, and D are 

atthesamepointsasinfigurel4; arrows show the direction of movement of the approaching ice. 

aspect, is produced by folding. The best development of this type is found on Gardiners Island, 

where the folds form several topographic ridges of considerable size. These ridges rise and fall, 

bend, separate, unite, cross, and merge into one another with an irregularity simulating that of 

n moraine, although generally preserving a marked alignment of features parallel with the ice 

FIGURE H.-Hypothetical condition of 

dminage system of figure 13 after being 

overridden by glacial ice. J;'oints A, 

B, C, and D are the same as in figure 

13. Dotted lj.nes indicate kettles. 

margin. Considerable material has at the same time been transported or removed by the ice. _ Taken as a whole, the structure must 

be regarded as intermediate between a true fold and an ice-shoved 

moraine similar to that between the Shinnecock Hills and Montauk 

Point. 

PSEUDO MORAINES. 

In the class of pseudomoraines are included certain ridges of the 

north shore which, although not of glacial origin, are so intimately 

associated with the moraines and so closely resemble them that 

they demand consideration here. 

From a point a little east of Port J e:fferson to Orient Point 

the morainal ridge hugs the coast, capping the tops of the bluffs 

that line the shore. The ridge is practically continuous, and at 

first sight the moraine appears for the 1nost part unbroken. At a 

number of places, however, sections along valleys cutting the ridge 

show that, although it possesses a kettle and knob topography indistinguishable from that of a 

n1oraine, it is in reality composed entirely of wind-blown sands (Pl. VIII), the true moraine 

being entirely absent. In fact, it is not unlikely that considerable areas of the ridges mapped 

as moraines are only pseudomoraines composed of dune sand, although they may contain a core 

of nwrainal drift. . 
36 GEOLOGY OF LONG ISLAND. 

OUTWASH DEPOSITS. 

EXTENT. 

The outwash is the most extensive of the Wisconsin deposits on Long Island. At first 

sight,· in fact, it· ap.pears to cover fully two-thirds of the surface of the island, but closer examination shows 'that the great plains stretching southward froni the morainal ridges are fn reality 

composite surfaces made up of outwash and projecting swells of older materials (Manhasset). 

N otwithstandii1g its wide extent, the outwash as a whole is riot normally developed, the :Manhasset formation even where buried exerting 'through its kettle valleys and allied features (p. 42) 0 a· considerable influence on the topography. Locally, however, especially near the moraines, 

several typical forms of outwash plains are represented. 

OUTWASH' DEPOSITS ADJACENT TO MORAINES. 

SIMPLE FANS. 

The simplest form of outwash accumulation is the fan-shaped deposit ma,de by water 

issuing from the ice front at a single point. These fans are closely related to th~ isolated cones 

described in the discussion of· the moraines but differ from them in that the points of emergence 

' of the feeding streams were usually lower down in the ice, and the volume of outflow and consequently the transporting power were materially greater. The amount of water in the streams 

forming the simple fans was, nevertheless, not very great, the streams deploying almost imnlediately on their emerg'ence from the glacial sheet and depositing close to the margin the material 

brought in suspension from the ice. The fans thus formed are usua]Jy small, being from half a 

mile to a mile or two in diameter, and have a comparatively steep slope, not uncommonly reaching 40 to 60 feet in a mile. They lie at short intervals along the southern moraine, the individual 

fans, although copfluent at their outer margins, still being distinctly recognizable. Along the 

northern moraine the plains are flatter, and the component fans are ·usually distinguishable 

only w~th difficulty. In general the fans head against the morainal ridges rather than at gaps 

in them, the streams that ca:J;Ile through the gaps apparently being more powerful than those 

that produce "the fans and carrying their load to a greater distance before depositing· it. The 

normal outline of an outwash fan is semicircular, but very few fans have this simple form, the 

direction of currents, th.e variation in the supply of material, ~nd the character of the under-

. lying surface all tending to produce unsymmetrical outlines. The individual fans are not 

commonly of a magnitude to be brought out with any degree of clearness by 20-foot contours, 

but indications of, then1 n1ay, never~heless, be seen at many points on the topographic 1nap. 

They are especially noticeable along that part of the moraine lying south of Peconic River. 

CONFLUENT FANS. 

In the same way that the simple fan is related to the isolated morainal cone the group of 

confluent fans is related to the· confluent cones and ridges of the moraines and like them represents the discharge of a number of adjacent contributory streams. The spacing of the conflue:Q.t fans, however, is not necessarily so close as that of the confluent 'cones, the greater spread 

of the fans allowing them to unite at much greater distances from their heads. The spacing of 

1nany of the co:qfluent fans is less than a mile, but the feeders of some were several1niles apart. 

All gradations in the form of the confluent fans, from those in which the individual fans pf the 

group barely touch at the edges to almost completely confluent forms, are observ.ed on the 

island, but even in the groups of the latter type the heads of the component members can in 

places be distinguished. The confluent outwash groups range from 1 mile to 6 miles or more 

·in diameter. The slope ranges from 40 feet in. a mile near the moraines to 15 or 20 feet a few 

miles away., 

The best ·example of such a group of fans on Long· Island is probably the plain bordering 

the Ronkonkoma moraine from the Half Hollow Hills eastward to Central Islip station, which 

embraces eight or more separate fans, at least five heading along the south side of the Dix 
PHYSIOGRAPHY. 

I-Iills and three or more along the moraine east of the gap north of Edgewood, the principal 

centers of dispersion being north of Edgewood, Brentwood, and Central Islip stations, respectively. (See topographic map, Pl. II, in pocket.) Another fine group of confluent fans _is 

found in the vicinity of Hic.ksville, the· component" parts heading at gaps in the moraine 

instead of against the moraine, as is more common. Other typical groups center in the vicinity 

of Prospect Park, Brooklyn, and near Richmond I-Iill, west of Jamaica. The great fan ,groui>s 

of eastern Long. Island are so· broken and modified by Manh.asset ren1nants that their typical 

character is lost. 

OUTWASH DEPOSITS DISTANT-FROM MORAINES. 

CONFLUENT PLAINS. 

In the smne manner in whi.ch the fans unite to form groups the groups eventually unite 

into broad confluent outwash plains. The union of the groups commonly takes place at a distance of 2 or 3 miles from the moraine, but the distance may be considerably greater where 

the groups are separated by older ridges, as at the Mannetto I-Iills, where the I-Iempstead and 

I-Iuntington-Babylon groups do not unite until they reach a point 6 miles south of the moraine. 

The lobate character of the contours, which is strongly marked in the fan groups '(see PL II, 

in pocket), becomes less distinct in the confluent plains,· the contours taking on broader curves. 

Thus in the I-Iempstead, West bury, East Williston, and New Hyde Park groups, which unite 

to form the I-Iempstead Plains, the lobate contours are very noticeable, but in the resulting 

plain the individual curves disappear and. the contours, aside 'from the minor bends at the 

drainage creases, show only a single· broad curve, best indicated by the coast line extending 

fron1 Jamaica east to :Massapequa, a distance of 16 miles. The slope of the plains decreases 

progressively from the heads of' the fans near the moraine and is commonly reduced to less than 

15 feet and in many places to hardly more than 10 feet in_ a mile along the shore. Where the 

outwash plain is well developed one may look over its flat floorlike s·urface for miles without 

observing any irregularities other than its channels. 

The individual outwash plains, such as the Hempstead Plains, unite with other plains, 

such as those of Babylon and Islip, to form a broad outwash belt reaching for many n1iles along 

the south side of the island. The greatest stretch of pure outwash (free or nearly free from 

Manhasset projections) is formed by the union of the plains mentioned, the extent of the belt 

frmn west to east being over 30 miles. · 

If the composite phiins (Manhasset and outwash) east of Connetquot River are combined 

with these more typical plains they form an almost uninterrupted outw.ash plain from Brooklyn 

to Promised Land, a distance of more than 100 miles. 

COMPOUND FANS. 

The tenn compound is applied to certain groups of fans differing from the norma,! confluent type. Among the more important of these compound forms are those termed successive 

fans, which are analogous to the double and compound ridges of the moraines, being formed by· 

deposition at successive stages of retreat of the ice margin. The chief points of difference are 

the greater vt>lume of water taking part in their 

fonnation and the greater distance between the[.___-__ _ 

s.tages of 'halt. The relations of successive fans to FIGURE 15.-Profl.le of a compound outwash fan of successive-

. · fi · plain type. one another is shown in cross sectiOn 1n gure 15. 

Suggestions of fans of this type were observed at a number of points, but few show a development as strongly marked as that indicated by the figure. One of the most accessible examples 

is found on the road south o:( Selden, where two or more southward-sloping fans with relations 

sirnP,ar to those shown in the figure art} seen. 

SECONDARY OUTWASH FEATURES. 

Besides the broader outwash features described in the foreg9ing sections there are many 

minor features that modify the general topography. Chief ~mong these. are the channels and 
gg GEOLOGY OF LONG ISLAND. 

valleys that· cross the plains at short intervals. Many of these are sharply defined and of 

considerable width, several being a mile or more across. The various types, representing several 

distinct modes of formation, are described on pages 45-48. 

Next to the valleys, the most· important of the modifying features of the outwash area are 

those portions of the Manhasset surface which project above the outwash at many points. 

The continuity of the outwash surface is also broken by many kettles representing buried ice 

masses, which are considered at length in the next section. Still another source of irregularity 

is the extramorainal fosse described in connection with the other types of valleys (p. 47). · 

KETTLES. 

To its glacial kettles Long Island owes many of its most pleasing features, including the 

hollows and basins which help to make the north. shore an attractive residence district, the 

lakelets among its hills, the broad fresh-water ponds, such as Lake Ronkonkoma, and apparently even certain of its bays. In few regions is more diversity of type exhibited by kettles; 

in fact, it is difficult to imagine a greater range of form than is found on Long Island. This 

diversity is due to the differences in the conditions of their origin. 

KETTLES OF THE TILL MORAINES. 

As pointed out in the discussion of the topography of the till moraines (p. 34), the basins 

in deposits of this type are relatively shallow and have gently sloping sides and comparatively 

regular outlines, their flowing contours being strongly contrasted with the highly irregular 

outlines of the stratified moraines. This 

-

-==-·'-------...;..· ____ __,..._,_,__~__;_· .,-. __.... _..___::::::::::..- chat~acterhistic i~ bfirought1o

6

u t by the c~oss sec wn s own 1n gure , a companson FIGURE 16.-N ormal profile of till moraine. 

1 of which with that of figure 17 will show 

the difference in profiles between the two types of kettles. So marked are the differences that 

they are even brought out by the 20-foot contours of the topographic map. Plate VI,.B (p. 32), 

is a reproduction on an enlarged scale of a portion of the topographic. map showing the till 

moraine north of Jamaica, and Plate VI, 0, represents a typical portion of the stratified moraine 

south of Riverhead. · 

The kettles of the till moraines usually marK the depressions between two accumulations 

of different stages rather than the sites of buried or projecting ice blocks, and have much less 

range in size than those. of the stratified ridges. In fact, a kettle less than 100 feet or more 

than a quarter of a mile in diameter is exceptional in a till moraine. · The tendency is toward 

elongated forms with the major axes parallel with the ice margin. Depths of ~ore than 30 

feet are rare, and the kettles are relatively isolated. · · · 

KETTLES OF THE STRATIFIED MORAINES. 

As can be inferred from the conditions of formation of the stratified ridges (p. 33), their 

kettles are both ;more diverse and more numerous than those in the till moraines. Although 

shallow .basins similar to those of the till ridges oc.casionally occur, the great majority of the 

kettles are relatively deep and steep-sided, the normal conwhich 

tour being 

is in 

similar 

marked 

to 

contrast 

that shown 

to that 

in cross 

of the 

section 

till moraine, 

infigure 

fig17, _ ~~ 

ure 16. The kettles of the stratified moraines rep.resent in 

part the depressions left by melting ice blocks, in part the 

FIGURE 17.-Normal profile of stratified moraine. 

hollows between successive ridges or other forms of stratified accumulation, and in part depressions between heaps of ice-shoved materjals. They have, therefore, a very grea~ range, both 

in size and in form. Basins hardly 15 feet in diameter are observed .here and 'there; and, ·on 

the other hand, some of the kettles have a diameter of one-fourth of a mile or more. In 

outline the kettles are equally varied, all forms from rounded depressions of the Lake Ronkonkoma type. to elongated and branching kettles sue~ as Great Pond, south of Riverhead, 
PHYSIOGRAPHY. 39 

being observed. The elongation, however, does not usually bear any close relation to the 

trend of the ice margin, and few linear groupings are noticeable, the c9mmon tendency being 

to an arrangement in crowded groups, as in the hills south of Riverhead. (See Pl. VI, 0.) 

KETTLES OF THE OUTWASH DEPOSITS. 

KETTLES }'ROM BURIED ICE BLOCKS. 

The simplest and least conspicuous _of the kettles are those resultmg from buried blocks 

of ice. The n1auner of their formation is brought· out by figure 18, in which a represents an 

ice mass bu-ried beneath the stratified outwash, b. On the melt-. 

~~! ~fn~~;l;,gt::;f::~~~ :t~~s ~~!r~:;: ~:~:~ :~~~ u~:: ~~~"*-<1j wash are broken down into a confused mass, but the high~r beds a c FIGURE 18.-Sectionillustrating the formation show only moderate sagging, and· the surface is marked by a ofakettlefroma buriedicemass. a, Buried 

shallow basin with gently sloping sides, d. This is the typical icemass; b,originaloutwashsurface; c,structureless sands occupying space of melted ice form o.f buried-block kettles, but where the ice masses are larger mass; d, resulting kettle. 

and the covering of outwash relatively thin the kettles are of 

greater depth and their sides 'much steeper. In fact, all gradations between kettles from 

small buried blocks and those from large projecting masses are found. The kettles orig~ating 

from completely buried blocks have as. a class one distinctive characteristic, namely, the universal absence of 

bowlders from their surfaces; but as bowlders are likewise 

FIGuRE 19.-Sectionillustratingtheformationofa lacking in many projecting-block kettles (where the ice was 

kettle from a projecting ice mass. a, Projecting free from englacial rock Inasses), this characteristic does not 

ice mass; b, kettle resulting from the melting of afford a criterion for the recognition of individual buri"edsimilar ice mass. 

block basins. Other negative characteristics of· kettles of 

this class are the absence of rims, either of till or outwash, the absence of terrace or shore 

features, and the absence of drainage channels leading outward from the depressions. "- . 

KETTLES FROM PROJECTING ICE MASSES. 

Forrnation.-The most characteristic and conspicuous of the ·outwash depressions are the 

kettles that result from the melting of large ice masses rising above the level of the surrounding 

outwash, as shown at a, figure 19. During the melting of 

1nasses of tllis ~ype the materials banked against the ice are 

let down and the debris contained within the ice is set free 

and is left strewn over· the ·bottom and sides of the kettle, 

as at b, figure 19. Few kettles of- this type are entirely free 

from bowlders. 

Steepness of sides.-The material let down as a broken 

mass around the perimeter of the depression rests with its 

FIGURE 20.-Section illustrating the relation between the slopes of kettle sides and the shape of 

melted ice mass. a-a, Steep kettle side resulting 

from steep ice face; b--b, gentle kettle side resuit:-

ing from sloping ice face. 

surface a_t an angle which depends to a large extent on the profile of the ice border. Where 

the ice presented a vertical face the material on slumping took the steepest angle possible, its· 

"angle of repose" giVing slopes as high as 30° to 

35° in some kettles (fig. 20, a-a); but where the 

ice presented a sloping face the material when 

let down lay at a much lower angle (fig.' 20, b-b). FIGURE 21.-Section illustrating the relation between the slopes of '\iVhere the -ice faces were regular the kettle sides 

kettle sides and the shape of melted ice mass. a-{L, Even slope 

resulting from melting of regular ice margin; b-b, irregular slope are likewise regular (fig. 21' a_:a) ; but where the 

resulting from the melting of irregular ice margin. mass of ice was irregular the slopes that resulted 

from its melting are correspondingly irregular (fig. 21, b-b). 

Form.-The shape of the outwash kettles is of great irregularity, every form from simple 

circular or oval to highly branching (Pl. XX, p. 116) or long linear channels being noted. Some 

·of the more c,onspicuous kettles are listed on the next page. 
.40 GEOLOGY OF LONG ISLAND. 

Typical kettles of Long Island. 

Circular or oval: 

Lake Ronkonkoma, 1! miles north of Ronkonkoma station. 

Irregular oval: / 

Lake Success, 2 miles south of Manhasset. 

Artist Lake, 1 mile east of Middle Island. 

Swan Pond, 2 miles northeast of Manorville. 

Great Pond, 2 miles southwest of Riverhead. 

Watermill Pond, near Watermill. 

Poxabogue Pond, 1 mile east of Bridgeha:t;npton. 

Branching: 

Kettles, southeast of Huntington station. 

Kettles, southwest of Huntington station. 

Kettles, 2 miles southwest of Rocky Point. 

Dix Pond kettle, 1 mile southeast of Wading River. 

Long Pond kettle, 2 miles southwest of Wading River. 

Mattituck Inlet, near Mattituck. · 

Linear: 

Kettle, 2 miles west of Middle Island. 

Kettle, 1 mile south of Fresh Pond. 

Scuttle Hole, 2 miles northwest of Bridgehampton. 

Size.-The normal outwash kettles range in dian1eter from a few rods to about a mile. In 

many of the linear. kettles, however, as seen in the table on page 43, the longer axes are from 

FIGURE 22.-Section illustrating the formation of kettle terraces by the melting of ice 

masses of especial shapes. a-a, Imperfect terrace; b-b, regular. terrace; c, ice mass. 

2 to 4 miles in lerigth. Although the 

great bays between the North and 

South flukes are not typical kettles, 

there is reason to ·believe that they 

owe their existence to nondeposition 

of outwash drift resulting to a certain 

extent fron1 the presence- of large ice masses in these basins. In a way, therefore, Great a:nd 

Little Peconic bays n1ay possibly be regarded as kettles, in which case the maxin1um diameter 

of such depressions would be increased to nearly 6 miles. 

Depth.-'-Many kettles of the outwash deposits ·are of considerable depth, their bottoms 

standing from 20 to 60 feet ·or more. below the surrounding region. Examples of the deeper 

kettles are given ~n the following list: 

Deeper kettles of Lon9 Island. 

Elevation 

- of sur- th rounding Dep · surface. 

Feet. 107 

160 

130 

105 

110 

70 

Feet. 50 

85 

80 

82 

80 

40 

Terraced kettles.-By terraced kettles are meant those showing flat benches on their sides 

at levels intermediate between the bottom and the rim. They appear to ·have at least three 

possible modes of formation. Probably the most common mode is by the melting of basal 

projections of the ice masses, as shown in figure ~2. Few such terraces are perfect, most of 

therri showing some irregularity that betrays their origin. ' 

A second. type is due to the shrinkage of the-ice mass (a; fig. 23) and the deposition of 

materials set free from the melting of the remaining block (b, fig. 23) in the space (c, fig. 23) 

between it and the inclosing outwash. It is difficult in the absence of sections' to verify the 

existence of the conditions indicated, but that the ice may carry sufficient detritus to form such 

a terrace i~ proved by the presence of loca:l outwash rims in a number of places: The amount 
PHYSIOGRAPHY. 

of drif.t in the lower part of glacial ice is almost invariably greater than in the higher parts, 

hence sufficient material to form a terrace within a kettle might be set free, even '~here no outwash rim was formed by the nielting of the upper portion of the ice. 

· A third type of terrace 

seems to have resulted from 

erosion in the free space 

between the shrinking ice mass 

and the kettle walls, ~ue either 

to the action of waves upon the 

gravel or sandy sides or to the 

S\~eeping of currents around the 

FIGURE 23.-Section illustrating the formation of depositional terraces between ice mass and 

kettle wall. a, Original profile of ice mass; b, later form of melting ice mass; c, sands and 

gravels deposited between ice and kettle wall. 

perimeter of the ice block toward the drainage channel which leads away from the kettle. Terracing of this sort·is of niinor importance except where combined with deposition, as in the type 

last described. 

~ Terraces were observed in a considerable number of kettles, 

~ 

/1 especially in the eastern part of the island. As this region was 

examined without a map (before the topographic survey by the 

FwuRE2-t.-Proftleoftcrracedkettlcnear United States _Geological Survey), it is generally impossible to. 

Lake Grove. give locations with suf;ficient accuracy to make then1 of value. 

Son1e very distinct terraces may" be seen where the road crosses the deep kettle valley threefourths of a mile northwest of Lake Grove and about 3 miles east of Smithtown Branch 

(fig. 24). Kettle terraces, however, ar~ not usually persistent, and these die out within a few 

hundred feet. . cv 

arou!et:~e ~~;;-~~~:;tt~! ::le:r~;::t:~ ~~~~~'~"'='-''~~~~~~ · -rials set free by the n1elting of the ice masses 

to which the kettles are due. Three forms FIGURE 25.-Profile of kettle with outwash rim (a). 

have been recognized. The most common form is probably the outwash fan ·(a, fig. 25) forn1ed 

by tl1e spreading out of fine materials over the surrounding outwash by rills from the n1elting 

ice. These fans are generally so flat as to be recognized with difficulty, bu_t the slopes of 

FIGURE 26.-Kettle rims. a, 'l'ill rim; b, bowlder rim. 

some are steep and the fans are easily recognized when 

seen in profile. 

_ A second form, much less common than the preced-· 

ing, is represented by more or less conical heaps (a, fig. 

26), analogous to the cones of a moraine (p. 32) and 

formed by small rills issuing from the ice several feet 

above the surface of the outwash plain. 

The third form is similar to the second and consists of irregular heaps of till or lines of bowlders (b, fig. 26) that have slid from the ice face as it melted, withotit the intervention of water. 

In the absence of sections it is difficult to · 

distinguish rims of the second and third types, 

but the first type is more readily recognized. The best exaiDI)le·was reported by D. W. John- FIGuRE 27.-0utwash rim adjoining kettle 2 miles northwest of southampton. (From sketch by D. W. Johnson.) 

son at a point near the gap in the moraine about 

2. miles northwest of Southampton. The drawing representing this kettle rim in :Mr. Johnson's 

notes is reproduced in figure 27, in which the view is northwest, the direction of movement of the 

outwash being toward the northeast. The notes of l\1r. Johnson also record" delta-like scallops, 

probably the discharge of melting ice blocks" near the north end of the Scuttle Hole kettle valley 

northwest of Bridgehampton. An example of what appears to be a till knoll is found bordering 

a kettle about a mile southwest of Cutchogue on the road to l\1attituck, at an elevation of about 

15 feet above the surrounding plain. Knolls of drift of intermediate or indeterminate types 

border the kettle valleys between Riverhead and Baiting Hollow and the kettles at the fairground southeast of Hulltington station. 
42 GEOLOGY OF LONG ISLAND. 

DOUBLE KETTLES AND KETTLE CHAINS. 

Double kettles are exceedingly numerous on Long Island; in fact they probably outnumber 

the simple isolated kettles .. Examples are shown at many points on the topographic map. Twin 

lakes are pres~nt in many such kettles. Not only are double kettles common, but triple kettles are not unusual and in some places, as in the area 

northwest of Riverhead (Pl. IX, 0) and in the Scuttle 

Hole locality northwest of Bridgehampton (Pl. IX, A), 

a considerable number of more or less connected kettles, 

which may be here appropriately called kettle chains, are 

found. 

FrGuRE 28.-Pre-Wisconsin In the double kettles and kettle chains the barriers 

drainage system in Man- separating the component members are nowhere as high 

hasset formation. A-B, h di 1 • 1 b · h 

Lineofsectionoffigure 3o. as t e surr<;mn ng p a1ns, as a ru e mng not more t an 

15 or 20 feet above the kettle bottoms. Generally these 

separating ridges retain· their original irregular or rounded contour, but 

well-defined notches cut by flowing waters .connect som.e adjacent kettles. 

The channel mentioned in the description of the Scuttle Hole kettle, below, 

is typical of the class. · 

FIGURE 29.-Kettle valley 

system remaining after 

themeltingofWisconsin 

icc masses. A.:.B, Line 

of section of figure 31. 

KETTLE VALLEYS. 

' 1 outwash I h f h 1 · d f 

r·· ;.;.;.:.·.~~~-~~·::·;~~ Amer~an:~i:her:a:rtc~m: ~;d:~l~~ee ;~~:r~s 

observation are kettle valleys so well developed. FIGU:J.tE 30.-Cross section along the line A-B of figure 28, showing residual ice masses partly buried by outwash. They are, in fact, among the most distinctive 

topographic features of Long Island. Briefly, 

they may be defined as long linear or branching kettles marking the positions of snow or ice 

masses that lay in the valleys of a previous suyjace and were covered with outwash. The conditions of their formation are brought out by , · 

!~~ ~~a::a:;to;:~h;~ 8~~~:: :a~!~~er~ r u ~::!~::~:;~ ized the Manhasset surface at many points FIGURE 31.-Crosssection along the lineA-B of figure 29aftermelting 

before the advent of the Wisconsin ice sheet. of ice masses. 

Figure 30 is a cross section along the line A-B of figure 28, showing the valleys occupied by 

snow ice or by residual ice masses left by the glacier during· a recession, together with a covering 

· of outwash spread over v~lleys and ridges alike. 

----------- Outwash level Figure 31 shows a profile along the same line 

F:;hasset ;~~~~~~---:.-~.:-~:-. ---.---~ after the me1ting of the ice masses of the valleys. 

VVhere the ice filling a valley was of uniform FIGURE 32.-Profile along ~he course of the kettle valleys of figure 29. 

thickness and melted at a uniform rate, an open 

valley resulted, but where the ice was of irregular thickness and melted at differing rates in 

different parts the overlying outwash was let down more or less irregularly, being thin or lacking in some places and of considerable thickness in others. VVhere it was thick the old valleys 

have been almost invariably more or less obstructed and have been converted into ~series of 

elongated kettles, as shown in profile in figure 32 and by the contours in figure 29. The kettle 

valleyf? of Long Is1and are not only numerous but large. Some of the more prominent are liste"d 

in the table on page 43. . 

The Scuttle Hole kettle channel is described in the field ·notes of D. W. Johnson, as follows: 

It leads directly southeast [from its head near the moraine] with slight meanders to the big kettle and pond [near 

the railroad]. The gorge is from 20 to 25 feet wide at the bottom, which is flat except where cut by a little trench of 

recent erosion. The sides are abrupt. The gorge ranges in depth from 6 to 8 feet at its [upper] end to 20 or 25 feet 

where it opens into the big kettle. It has two [or more] insignificant lateral branches, both from the north and only a 

few rods long. The channel is cut sharply into the outwash plain, there be~g no slope toward it [other than the 

sides of the valley]. At the east end is a broad shallow kettle. This latter served as a receptacle into which the waters 

accumulated [coming from the northwest portion and cutting the minor trench mentioned]. 
.. 

U. S . GEOLOGICAL SURVEY PROFESSIONAL PAPER 82 PLATE IX 

TOPOGRAPHIC FEATURES OF LONG ISLAND, NEW YORK"""""""'"' 

S c ale s2~oo 

~=c~Et~~~~O~EEEEEEEEEEEE~============~ 8 

Contour interval 20 £eet . .IJa;t;r,un is 7J1..e.Q;n, 8~ leveL. 

1913 
PHYSIOGRAPHY. 

Large kettle valleys of Long Island. 

Location. Character. 

43 

Length in 

miles. 

Ono milo southeast of Huntington station (Fairground) ..... Irregular, completely closed............................................. 1 One milo west of Middle Island .......................... __ ._ Long, narrow, branching, partly closed (Pl. XX, p. 116) .. _____________ . 4 

Two miles north of Middle Island _ .. _ .. _ .... _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Irregular branching, partly closed (Pl. XX) ___ . ___ ...... _._ ..... _....... 2 

Onc-balf mile east of Middle Island ........... _ ... _. _ _ _ _ _ _ _ _ Irregular, partly closed, containing Artist Lake (Pl. XX) __ ......... _ .. _ 1 Vicinity and north of Lake Honkonkoma ......... _ .. _ _ _ _ _ _ _ _ Highly irregular, practically closed kettle-valley system (Pl. X) _ _ _ _ _ _ _ _ 3 

Two m~essouthwest of Hocl~y Po~nt. .... -.- ________________ Irregular,completcly closed (Pl. XX) ... ________ . __ ............. ___ .... _ 2 

Two m_Ilcs southwest of \Vf!;dmg ~1vcr station ... ___________ Irregular kettle-valley system, partly closed, containing Long Lake ... _. 2 

One m~e southeast of Wadmg HIVe~ .............. _ ... ______ -Branching, contains Deep Pond, completely closed._ .. _________ ._.______ 2 ~nc mil~ south of Fresh POI?d Landmg ........ ________ . _____ Valley, partly open, and kettle chain (Pl. IX, B) ______ ._. __ .. _.________ 3 1 hroo mil~s northwest of Hivorhoad ... _. _. ___ .. ____ . _ _ _ _ _ _ _ _ Kettle chain (Pl. IX, C) .. _. __ ...... _ .. _____ ._ ... ____________ .__________ 4 

Ncar Mattituck (Inlet) ........................ __ . _ _ _ _ _ _ _ _ _ _ _ Branching, reversed drainage (Pl. XI, C) __ ____ .. ___________________ . _. _ 2 

'rwo miles northwest of Bridgehampton (Scuttle Hole) . _ _ _ _ _ Kettle chain and valley, mainly closed (Pl. IX, A) ______________ . _ ... _ _ 3 

PITTED OR KETTLE PLAINS. 

The term_ kettle plains is here app]ied to those plains in which kettles are so numerous as to 

be the controlling factor in the topography. All gradations between isolated kettles (a, :fig. 33) 

and . kettles so closely crowded 

!:~~~~:v!~~:~::rs:u:~~~ ~-5--:- .. =--::~-.- _·.- .~:-·. .-·· .. ----- ~---------.5-. __ _ 

island. 

plain(b,:fig.-33.)ai,efoundonthe In fact, not a few of the FIGURE ~ 33.-Proflle of kettle plain. ~ a, Isolated kettle; b, divide between kettles rising just 

to level of plain; c, kettle surface with no remnants rising to surface of plain. 

pitted or· kettle plains grade off . 

into irregular surfaces on which no trace of the original plain is left (c, :fig. 33). Where the 

kettles are more or Jess isolated and are separated by flat outwash areas,, as iri the plains 

west of Cold Spring station and southwest of Huntington station (Fairground), the kettleplain character· is very apparent, but where they are more crowded the significance of the 

topography is less easily recognized. In such places the sky line affords the most reliable 

clue. If on looking from one of the higher points, such as b in figure 33, it is found that, notwithstanding the ~bsence of flat remnants, the rounded knohs rise to a nearly uniform ~levation 

(as they do in the direction of a) it is usually safe to assume that the surface is a pitted plain. 

An occasional flat-topped remnant makes the recognition much easier. The region northwest 

and west of Riverhead, the district about Bridgehampton, and the country between Riverhead 

and Mattituck are among the best examples of kettle plains. 

KETTLES OF DOUBTFUL ORIGIN. 

About 21 miles northwest of Babylon, east of the road leading toward the Half Hollow 

Hills, is a shallow kettle large enough to be shown on the topographic map, and a number of 

smallm; basins are ·hidden by the underbrush of the vicinity. _Other distinct kettles were 

noted in the vicinity of Farmingdale. The former are more than 10 miles and the latter 

8 miles from the moraine from which the outwash issued and 5 to 7 miles south of the outer 

moraine. There are no evidences that the glacial ice ever extended to this region, and even 

if it did there would seem to be no possibility that ice blocks would have persisted from a 

period antedating the oldest moraine until near the close of the building of the youngest. 

Moreover, in the older outwash of this part of the island there are no kettles. Therefore, as th~re 

are no evidences of an extramorainal ice invasion or of snow-ice masses during the upbuilding of the earlier outwash, it would .seem that the kettles, whatever may be -their cause, 

were developed during the formation of the later outwash deposits themselves. The accumulation of snow or snow ice in channels temporarily dry and the freezing of the smaller deploying rivulets of the broad outwash fan and the burial of the ice thus formed by subsequent 

deposits suggest themselves as possible causes. It is to be noted, however, that the basins 
44 GEOLOGY OF LONG ISLAND. 

are all small and that they lack the sharp an.d irregular siopes that characterize most ~f the 

kettles of Long Island, and it may be that they have -resulted from some unknown peculiarity 

of deposition. Similar depressions have, in fact; been noted by the writer in the flood-plain 

deposits of ·Mississippi, Ohio, and Wabash rivers, in.whose formation ice has played no part. . - - , 

KETTLES OF THE MANHASSET SURF ACE. 

Kettles on the Manhasset surface are exceedingly numerous and may be divided into 

those due to ice shove and drag,. including obstructed and modified valleys, and those due to 

deposition. In. the obstructed or modified valleys resulting from ice shove or drag there has 

been invariably a reworking or readjustment of materials, the accumulations being essentially 

morainal. The formation of ... kettles in this manner has been discussed in connection with 

moraines (p. 35, figs. 13 and 14): The kettles due to deposition are represented by the kettle 

valleys and Rett]e chains described in the preceding section. · . 

PSEUDOKETTLES. 

Besides the true kettles, comp1ising hollows between glacial· rirlges and basins left by 

melting ice masses, there are on the island several other forms of undrained depressions. Among 

these may be mentioned the unfilled areas· between· the moraines and the confluent outwash 

fans (p. 47), the sharp-angled, kettl~-1ike basins and troughs of the sand-dune areas, and the 

irregular depressions in landslide surfaces. In wet seasons small pools form in the landslide 

depressions and small shallow temporary ponds gather among the dunes. 

VALLEYS. 

The valleys of Long Island exhibit a wide range of form according to the conditions under 

which they were produced. The types include those formed by glacial water.s as well as those 

made by ordinary streams; all ages from early Pleistocene to Recent are represented, and both 

original and modified forms are fou.nd. 

PRE-MANNETTO VAY ... LEYS 

The oldest valleys on Long Island of which a record exists are those eroded in the Ore-

. taceous formations -before the deposition of the Mannetto gravel, but as these were completely 

filled by the gravel deposits they have no direct topographic expression a_t the present time. 

Nevertheless, as is pointed out elsewhere (p. 29), they exerted an important indirect influence 

on the subsequent topography by their control of Mannetto deposition. The deposits of the 

Mannetto reached lesser elevations in the broad, low Cretaceous lowlands than over the higher 

surfaces, as a result of which the post-l\1annetto erosion tended to follow the lines of the earlier 

drainage. ,. · VALLEYS IN MANNETTO GRAVEL. 

The valleys of the Mannetto gravel differ greatly in extent, all sizes, fron1 the small notches 

around the borders of the plateau remnants, as ~ the l\1annetto Hills (Pl. III, p. 28), to broad 

lowlands' many miles across, being represented. Of the-latter, the so-called Jameco Valley, 

crossing the island from north to south in the region between Hempstead and Brooldyn and 

oc~upied by the Jameco gtavel, is-the best example, but inasn1uch _as it is a buried valley rather 

than a feature of the present topography it need· not be considered further. -

Intermediate between the larger and smaller valleys mentioned are the valleys of the hills. 

In the Wheatley ii.ills, the most westerly considerable ren1nant of the Mannetto gravel, the valleys 

radiate to the southwest, south, and southeast from the crest near Wheatley village (Pl. VI, D, 

p. 32). Originally the valleys were probably deep and V-shaped and were separated by fairly 

straight, flat-topped interstream ridges, probably not unlike those in tlie younger deposits on 

the south side of the Half Hollow I-Iills (north and northwest of Wyandanch), valley depths of 

100 and 150 -feet being not improbable. Owing to the passage of the various ice sheets over 

then1, however, the·valley walls have been broken down, the minor ravines largely obliterated, 
PHYSIOGRAPHY. 45 

and tP.e main valleys obstructed and more or less filled with both till and stratified drift, giving 

the whole area a decidedly morainal superficial aspect, although the major contours, as brought 

out by the topographic map, are plainly due to erosion. The hills apparently represent a 

Mannetto surface dissected to the extent that the,valleys met from all directions about a central 

crest and were separated by sharp ridges. The crest and ridges probably stood not ·far from 

the level of the original Mann~tto surface, but little or nothing in the shape of flats at this 

altitude appears to exist. It is to be noted that the valleys on the north side of the hills have 

been completely obliterated by the ice sheets and their deposits. -

The Dix Hills and the snutll n1ass of hills northwest of them are very sin1ilar in their topography to those near Wheat.ley, showing the same obscured or obliterated valleys on the north 

side, the san1e modified and partly filled valleys on the south, and the same superficial morainal 

topographic features. The dissection appears, however, to have been less advanced than in 

·the Wheatley I-Iills, and it is probable that in the centr~l part of the Dix Hills there were several 

rmnnants of the original Mannetto surface standing at an elevation of about 300 feet and having 

a considerable extent, although less than in the l\1annetto Hills. 

The Mapnetto Hills afford the best-preserved examples of unmodified v~lleys in the :ManIietto gravel, as only the north end of the hills was overridden' by ice. The rough parallelism 

of the valleys and the lack of conspicuous branching, features which are so noticeable in the 

Wheatley Hills. (Pl. VI, D, p. 32) and on the southeast side of the Dix Hills, are even more 

conspicuous on the Mannetto :Hills, especially on their west flanks (Pl. III, p. 28). All the 

valley!;) have served as channels to conduct glacial drainage southward from the ice front as it 

laid along the nloraine, hence they are considerably modified from. the pre-Wisconsin forms. 

Several fine terraces nuty be seen in the valleys north and northeast of Plainview. It is noticeable that 1nany of the longitudinal divides separating the valleys are reduced considerably 

below the 280 to 300.foot level (that of the Mannetto surface), although a few remnants, usually 

flat topped, occur well out on the spurs, as is shown by the topographic map. The chief remnant 

is found in the flat-topped ridge, in places of considerable width, stretch~g southward from the 

moraine to the vicinity of Bethpage. 

The valleys o'f the Mannetto. gravel above described were mainly developed in the post-

~[annetto stage, imn1ediately following the Mannetto deposition, for the distribution of the 

succeeding formations, including the Jameco, Gardiners, Jacob, and :Manhasset, shows that 

relatively little further erosion took place after that stage, although trenching continued near 

the heads of the strea1ns mnong the hills, as in the Wheatley, Mannetto, and DL"'{ masses, until 

the covering of the hills by Wisconsin drift' and to a less extent until the present time. · The 

valleys of the east side of the l\1annetto ·Hills extend considerably below the level of the·l\1anhasset (as represented in the Bethpage and Half Hollow Hill remnants) and therefore belong 

to a post-Manhasset period of erosion. 

OLDER VALLEYS IN THE MANHASSET FORMATION .. 

The valleys in the :Manhasset formation are everywhere conspicuous features, cutting the 

fonnation fron1 its surface at an elevation of 200 feet or less to a point considerably below 

sea level. As post-Wisconsin erosion has accomplished little more than a slight notching of 

the blufl's and steeper hillsides, practically all the valleys shown on the topographic map belong 

to the older or pre-Wisconsin group. Most of them do not, however, show the original forms, 

for, with the exception of the Nissequogue Valley near Smithtown· (Pl. X, p. 46), there is 

nowhere in Long Island a Manhasset valley of notable size that has not been materially modified by ice action or the deposition of glacial debris. In many valleys, however, the modification was confined largely to the deposition of a superficial mantle of drift which, although 

giving rise to minor irregularities that in places simulate low morainal accumulations on the 

valley sides, does not obliterate the chief characteristics. The valley at Glencove, that of 

_:Mill Neck Creek, other valleys near Oyster Bay, the OCold Spring valley, and the valleys east 

of Northport are examples of this class. 
46 GEOLOGY OF LONG ISLAND. 

When the action of the ice was more energetic or the deposition took place on a larger 

scale, many old valleys were obstructed and even partly obliterated, the remarkable kettle 

valleys described in detail on page 42 being produced. 

The" western half of the Nissequogue Valley at Smithtown is in an area practically free 

from Wisconsin drift and was protected from erosion by a filling of snow or ice. We have 

here, therefore, a practically unmodified remnant of the original Manhasset drainage $ystem 

with its deep, sharp. trenches and branching valleys. It is not unlikely that such systems 

existed at many other points on the island but have been :materially modified by the passage 

of the ice over them or by more or less complete burial beneath Wisconsin drift. Remnants of 

such modified systems are found north 9f Lake Ronkonkoma (Pl. X), in the vicinity of Middle 

Island (Pl. XX, p. 11_6), near Wading River, and northwest of Riverhead (Pl. IX, 0, p. 42). 

South of the Ronkonkoma moraine the :Manhasset valleys are represented by the short 

V-shaped valleys cutting the Mannetto and Half Hollow hills and by the broad, shallow, illdefined valleys leading southward to the coast in regions where the Wisconsin outwash is thin. 

The valleys of the hills mentioned may be taken as representing a· type of short valleys such as 

were probably developed also in the high bluffs at many places along the north shore; they are 

now represented by the valleys at the heads of Huntington, Centerport, Stony Brook, and other 

harbors. 

It is difficult to describe with any degree of accuracy the broader Manhasset valleys south 

of the moraine, as it is generally impossible, even on the ground, to differentiate sharply between 

the Manhasset and the outwash gravels. The Manhasset topography was in general low, with 

broad, gently rounded divides and perhaps equally ill-defined valleys, the outlines of. which 

were still more obscured by the deposition of the subsequent outwash. A ·somewhat sharply 

marked valley, however, appears to have led southwestward from the vicinity of Lake Ronkonkoma, uniting with another valley from the region east of Hauppauge at a point a little· 

north of the railroad, wh~nce it extended southward along the course of the present Connetquot 

River. (See Pl. II, in pocket.) Apparently its sides rose steeply to a height of 30 feet or 

· more above its bottom, and it had many tributary valleys, especially from the east. A smaller 

valley probably entered the sea near Patchogue, and another large one, exceeding even the 

Connetquot channel in size, extended southward from Yaphank. This valley had a width 

of over 3 miles in places and was bordered by bluffs or steep slopes, probably rising originally 

in places to heights of not less than 80 feet above its bottom. Even after receiving the filling 

of outwash from ice along the Ronkonkoma moraine the bottom still stood, near the site of the 

railroad, at h~ast 50 feet below the surrounding :Manhasset S'!Jrface. 

VALLEYS ASSOCIATED WITH THE MORAINES. 

Minor channels.-The simplest class of valleys of the. moraines are the small wash channels 

extending do~n the sides of the morainal cones and ridges. The stratified morainal deposits 

·were for the most part built up from small rivulets that were 'alternately overloaded and underloaded with glacial debris. When overload~d the water quickly deployed and ran down the 

surface of the deposits in many streamlets, effecting but little erosion. On the other hand, 

when underloaded the water, instead of spreading and depositing, tended to deepen some one 

of the many charinels of. the deploying rivulets and to concentrate itself in that single channel, 

which was soon enlarged into a valley of some magnitude. The tendency to form such channels 

was probably most pronounced in the closing stages of morainal building. 

' The water in its passage downward followed the natural hollows in the moraine, here 

entering a kettle and there passing around some knoll. At the start the channels were therefore 

of considerable irregularity, but as their development continued they tended to straighten, the 

minor bends being obliterated and only the long, swinging curves remaining. The channels 

are commonly from 15 to 50 feet wide, although some are wider, and are generally flat-bottomed, 

though some are slightly trenched by su?sequent erosion. The sides are commonly steep and 

in places rise to a height of 30 feet or more. Remnants of terraces are seen locally, but few are 

PHYSIOGRAPH·Y, 47 

well developed. The slope of the channels is commonly between 1 to 50 and 1 to 25, or 100 to 

200 feet to the mile. :Many groups of channels have a semiradial development from some central 

height, but as a rule the channels extending southward are much better developed than those 

nnming in other directions. The best areas for tracing such channels· are in the great irregular 

hills of the Ronkonkoma moraine south of Peconic River (Pl. VI, 0, p. 32), southeast of Riverhead, and between Hampton Park (Southampton) ·and Sag Harbqr. ' 

J{ettle channels.-The small erosion channels that mark the pathways of waters escaping 

from an ice block into an adjoining kettle or from one kettle into another (fig. 34) are described 

and examples are given in connection with 

kettles (p. 42). They should not be con- I ~-------~ 

founded with the kettle valleys, which are L._: _______________ ,;,_ __ ~ 

of entirely different origin. FIGURE 34.-Profilo showing a channel between kettles. 

Outflow channels.-The pronounced valleys leading through . the ~orainal ridges and 

commonly cut to the level of the outwash plains bordering the moraines on the south are known 

as outflow channels. Through them flowed large glacial strean1s issuing from the ice margin 

or from the waters impounded between the ice front and the moraines; hence their origin 

differed in several essential particulars from that of the minor channels just described. They 

are relatively broad, few being less than 100 feet wide and some from one-fourth to three-fourths 

of a mile. The skaller channels commonly merge into outwash fans, of which they were the 

feeders, but the larger ones are generally prolonged as definite valleys across the outwash plains, 

being, in fact, the heads of the outwash channels described on page 48. The floors of the channels 

are mostly flat, with perhaps a· small central furrow marking a late phase of outflow or with low 

terraces on one or both sides of the valleys.. In general the higher points of the valley walls are 

constructional (moramal) rather than destructional, indicating that the gaps are mainly original 

features and are not clue to erosion by waters forcing their way across the moraine. The 

locations of the most prominent of the outflow ch~nJ?.els are indicated on the geologic map, 

Plate I (in pocket). 

Outer morainal fosse.-On Long Island, as elsewhere, it is not unusual to find at the base 

of the outer border of the moraine a longitudinal depression or fosse lying between the ridge 

and the adjoining outwash platn (fig. 35). This feature is not especially well marked on the 

island, although some good local examples are seen. None are very deep, 5 .to 10 feet being a 

common depth,. although a few are deeper: Most of them appear to represent unfilled depressions behind the outwash fans, the tendency to deposit being least marked along the moraine 

at right angles to· the direction of the emerging stream. Fosses due to this cause are without 

erosion features and commonly show by their topography their constructional origin. Other 

fosses, however, have the form of somewhat indefinite channels, as if occupied and modified 

by outflowing waters at some period subsequent to their formation. It is even possible that 

some are of the nature of true outwash 

r-------~--------... channels and mark the positions of out-

~---,----_,....;----------:0-ld-er_o_u_tw-a~shl wash streams that happened to occupy· Youngeroutwash lnnerfosse ·Moraine Outerfosse 

at the closing stages of outflow positions FIGURE 35.-ProfUe showing relation of inner and outer fosses to moraine. next the moraine. 

Inner morainal fosse.-The inner fosse, although per.Q.aps not so common as the outer on 

Long Island, is a much more striking feature. In its simplest form it is a channel running along 

the inner face of the moraine, apparently due· to 

Moraine 

N. 

the lateral flow of water between the. ice and the 

1noraine (fig. 35) .. What is probably a channel of s. 

this type is shown at a in figure 36, from field notes 

of D. W. Johnson, who says: "This depression [near FIGURE 36.-Profile showing fosse (a) at inner base of moraine near Duck Pond Point. (After sketch by D. W. Johnson.) 

Duck Pond Point, Mattituck] is peculiarly constant 

for a considerable distance east and west," making a sharp trench in the inner face of the 

moraine. 
48 GEOLOGY OF LONG ISLAND. 

The most remarkable fosses of .this type occur on the north side of the Montauk Peninsula, 

between Fort Pond and.Napeague bays, 1! to 3! miles west of Montauk station, where there is 

a succession of channels having a northeast-southwest direction parallel to the moraine. The 

channels, although too crowded for accurate delineatio-n, are clearly indicated on Pl~te VII, 

0 (p. 34). An examination of this map will show four main channels cutting the 100-foot 

terrace north of the moraine (dotted) and just southwest of Fort Pond Bay (A). These channels, 

which are the deepest and most conspicuous of the fosses, open to the southwest upon a bench 

of about 60 feet elevation and northeastward they extend to· sea level. They are flat-bottomed, 

steep-sided erosion channels and appear to have been outlets for waters issuing from the ice 

ma~gin at successive halts and escaping into Fort Pond Bay and thence through the pond 

depression into the ocean. Figure 37 shows a cross section of the moraine and terrace with the 

fosse channels. Indications of smaller channels on the lower slopes of the terrace are seen 

between the railroad and the-shore south of Rocky Point (B, Pl. VII, 0). 

A second group of channels is found southwest of the first but draining in the opposite direction, to the southwest.. The more southerly channels of this group appear to have carried 

the escaping waters to a gap leading southward across the moraine (C, Pl. VII,. 0) 2 miles west 

of }lither Plain life-saving station, whereas the .more northerly drained into a channel (D, Pl. 

VII, 0) leading we~tward to N apeague Bay near Quince Tree Landing, whence the water escaped 

to the ocean through the gap now closed by the long connecting beach. 

As indicated by their form the main features of the fosse channels described are erosional, 

but there is some reason to believe that their position and to some extent their form and depth 

may be due to folding. Thus on Cape Cod, where the walls of similar channels are shown in 

cross section in the bluffs, they are seen to represent actual folds whose troughs were simply 

widened and otherwise shaped by outflowing waters. . In' the absence of sections, however, it 

is impossible to determine what part, if any, folding has played in the formation of the Montauk 

channels. 

One of the largest of the closed inner-fosse depressions is that lying along the north face of 

the Ronkonkoma moraine from a po~t near Lake Grove, north of Lake Ronkonkoma, eastward 

through New Village, Selden, and Coram to Middle Island, a distance of nearly 10 miles. Its 

extent and outline ate both well brought out by the 100-foot contour of the topographic map, 

although this contour does not quite close. The northern slopes of the fosse are gentle, being 

formed mainly by the ~1anhasset surface with its shallow drainage creases more or less modified 

by their outwash :fillings. The south flanks are steeper, being formed by the inner face of the 

Ronkonkoma moraine: In the eastern part the. bottom is marked by the great kettle valleys 

Terrace level 

of the Middle IslaJ!.d region. The 

fosse has no surface drainage, 

the waters falling 'upon its sides 

and bottom escaping by under- FIGuRE 37.-Profile of inner-fosse channels west of Fort Pond Day, Montauk peninsula. ground percolation through the · (Pl. VII, C, A). a, Small channel on lower slope of terrace. sands beneath the moraine. 

The fosse now occupied by Peconic River is fully as large as the one just described. and is 

of the same general character, although· it is an open instead of being a closed depression. 

Lying lower than the other, its bottom cuts the water table, giving rise to the river that enters 

Great Peconic Bay at Riverhea~. 

OUTWASH CHANNEI.iS .. 

The outwash channels, which include all the drainage depressions of the outwash deposits, 

are among the most interesting of the topographic features of the island, presenting in their 

various types, forms, and relations many attractive problems. 

RELATION TO MORAINES. 

_ :Most of the larger and more important of the outwash channels head in gaps in the morai11e, 

being the continuations of the outflow channels described in connection with the n1orainal 
PHYSIOGRAPHY. 49 

valleys. Among the most important of these may be mentioned the one leading southward 

from the Harbor Hill moraine at Roslyn and the Centerport-Babylon channel leading southward from the same moraine near Greenlawn; there are also many smaller unmapped channels 

h~ading in gaps in the moraine between Yaphank and Montauk. (See geologic map, Pl. I, in 

pocket.) 

Besides the larger and better-defined channels there are a. considerable number of smaller 

drainage lines heading either against the moraine or at one of the minor morainal channels. 

Some of these can be seen by tramping a mile or two almost anywhere along the south base 

of the Ronkonkoma moraine, but they are less common in front. of the llarbor I-Iill ridge. 

Channels of a third class start at points on the outwash plain some distance from the moraines and are apparently formed not by definite streams issuing from the n1oraine but by the 

gradual gathering together of waters from various sources, including those that had previously 

deployed and deposited their suspended .material. The channels developing near Melville between the Mannetto and Half Hollow hills are good examples of this class. 

A fourth class _is due to the collection of the outwash waters through the agency of an older 

topography instead of by normal conditions pertaining to outwash accumulation. Such channels are exceedingly numerous on Long Island. Good example~ are afforded by the channels 

uniting to form. Carmans River between Middle Island and Yaphank, the stream less va.lleys leading to Peconic River west of Riverhead, and the many valleys 

leading 

Channels 

to the estuaries 

of still another 

of Moriches 

class, 

and 

represented 

Shinnecock 

by 

bays. 

the great 

~ 

Connetquot 

originated in 

channel 

ice masses 

leading 

not 

southward 

resting against 

fromSmithtownBranch, 

the moraine but are 

~ 

otherwise similar to those heading at the morainal gaps. 

RELATION 'l'O KETTLES. 

A considerable number of minor outwash channels head 

in kettles, but as a rule the water from melting ice blocks 

was too small in amount to cut deeply into the gravels, and 

feW SUCh channels are large enough tO be shown on the FIGURE 38.-Sections of terraced channel lead· 

ing westward from Lake Ronkonkoma. topographic map. They are probably most abundant in 

the kettle-valley region northwest of Riverhead, but similar channels lead from the lower 

kettles southeast of Scuttle Hole, near Bridgehampton (Pl. IX, A, p. 42). A larger and 

very sharp and definite channel leads westward from Lake Ronkonkoma and joins the 

main Connetquot channel (Pl. X, p. 46). As the Connetquot channel issued from a large ice 

n1ass occupying the Nissequogue Valley, it may itself be regarded as originating in a kettle, 

although the kettle was finally left open. 

FORMS 01!' CHANNELS. 

The valleys of the outwash are of two distinct types-true erosion valleys and interfan 

creases. The former are well-defined channels with flat bottoms, terraced borders, and steep 

banks (fig. 38); the latter are broad, shallow sags between two confluent outwash fans represented on the map by bends in the contours, but many of them ha:r;dly apparent to the eye. 

The two types occur in combination at many places, however, and at such places the faint 

interfan creases are accentuated by true channels, as in the region between Edgewood and Centrnl Islip stations. Channels of this type are most conspicuous at a distance froin the moraine. 

Terraces are of widespread occurrence in connection with the outwash valleys, there being 

probably very few such channels that in the course of a mile do not show SOplething in the 

shape of a terrace. A given terrace, however, is as a rule not persistent for any great distance, 

generally dying out in a few hundred yards and being replaced by another at a higher or lower 

level. So far as observed there is no uniformity in their number or elevation. They appear 

1629°-14-5 
50 GEOLOGY OF -LONG ISLAND. 

to be rather accidental remnants left at various altitudes during the practically uninterrupted 

period of downcutting. So. numerous are the terraces that specific n1ention would be without 

value. The type is illustrated in figure 38, which shows cross sections at intervals of about oneeighth of a mile in the channel leading westward from Lake Ronkonkoma to t_h.e main Connetquot Channel (Pl. X, p. 46). 

Although the bottoms of 01.1twash channels are commonly flat there are numerous exceptions. The most common irregularity seems to be a low, rounded, barlike ridge along the 

center, such as that shown in figure 39, a, which represents the profile of a large channel along 

the road just south of Commack. The bars are commonly of no great extent, dying out gradually both up and down the channels. In places two or more overlap en echelon and others are 

more or less confluent and irregular. AU gradations between normal bars ·and the ridges and 

terraces separating the double channels described in the next paragraph are found. 

c 

It appears that in some places after the deposition of 

the bars above described the volume of water became lessened 

and was no longer able to fill the whole of the original channel but divided into two small streams, one flowing on each 

side of the bar. These streams gradually cut for themselves separate channels, the intervening bar eventually 

being left as a ridge, as shown .in figure 39, b, which represents in cross section a southwestward-leading channel about 

1! miles north and a little west of Lake Ronkonkoma. 

FIGURE 39.-Forms of outwash valleys. a, Channel 

with bar south of Commack; b, ridged channel!~ It seems to have happened not infrequently that du'!'-

rnilesnorthofLakeRonkonkoma; c,doublechan- .ing the closing stages ,of outflow the waters of the broader 

nell mile west of Holtsville station. outwash channels were reduced to two small streams, one of 

which hugged one bank and one the other. These streams also cut subordinate channels, which 

were separated by a broad, flat terrace representing the uneroded part of the floor of the larger 

outwash valley, as shown in figure 39, c, which is a profile across a small channel1 mile west of 

lioltsville station and a quarter of a mile south of the railroad. A similar and larger double 

channel is shown in the outwash valley between the Mannetto and Half Hollow hills, each side 

of which is marked by a broad~ sharp channel that is well brought out by the geologic map 

(Pl. I, in pocket). _ 

The slope of the bottoms of the valleys is usually gentle and uniform from the moraines to 

the sea, the rate.being.commonly from 10 to 15 feet to the mile but flattening in the lower mile or 

tw:o, apparently owing to a slight sinking of the 

land, which has pern1itted the lower parts of the 

valleys to be. occupied by estuaries of the sea and 

has caused a slackening of the drainage. 

As long ago as 1877 Elias Lewis, jr./ called 

attention to the greater average steepness of the 

right-hand or westerly banks of the outwash 

.X 

c: 

(II 

..c 

channels as compared to the easterly or left- FIGURE 40.-Profile showing relative steepness of east (left) and west (right) banks of Long Island valleys. hand banks (fig. 40), stating that the difference . . 

had been long noted by travelers and referring it to the earth's rotation, as a consequence of 

which the strean1s are thrown against the westerly banks. Seven years later G. K. Gilbert 2 discussed the deflective force due to the earth's rotation, limiting it to streams of slight fall and 

citing the Long Island streams as good examples .. The observations of the writer and his 

assistants seem to indicate that probably four-fifths of the ordinary shallow valleys of the outwash plains lying south of the outer moraine have steeper banks on the west than on the east 

side. In some valleys the difference is as marked as· that shown in figure 40, but in others it 

is hardly appreciable. The development, however, must be recognized as remarkable when the 

weakness of the force is considered. 

Local exceptions to the general rule of steep westerly banks were observed, but the only 

notable ones are in the relatively deep valleys formed where ~he outwash streams have cut 

1 Am. Jour. Sci., 3d ser., vol. 13, 1877, pp. 215-216. 2 Am. Jour. Sci., 3d ser., vol. 27, 1884, pp. 427-432. 
PHYSIOGRAPHY. 51 

ip.to the Manhasset formation. IJ.?- such valleys the steepness of the bank depends on the curvature of the streams, being greatest on the outside of the bends. In straight reaches the banks 

are of nearly equal slope.-

Although the cutting of the valleys of this type began in Wisconsin time, the erosion and 

shaping of the banks has extended to the present day, especially. along the south .shore, where 

the water table con1es to the surface and supplies the short streams with water. 

Many of the outwash valleys have been partly obstructed by the formation of deltas across 

the main valleys at the mouths of tributary streams. Usually the flow of water in the larger 

valleys has been sufficient to cut through the deltas, but ~·O·Q· •.• ·=. = ..••. 

here and there the obstructions have not yet been over- -.--------r.,---

come, and wet weather. ponds of considerable size accu- _-4t~~i~i~ 1nulate behind the barriers. The best example of an t:U. ~~~~~~;g~~}:.~ 

obstructed valley with ponded water observed was on the -~s.~e~~~k~r.~'eb.~~~~~~~§§~~~ 

northeast-southwest road three-fourths of a mile northwest of Lake I\onkonkoma, where a marshy pond over a FIGURE 41.-Section illustrating formation of amphithe- aters by spring sapping. a, Qriginal point of emerquarter of a mile in length was seen in 1903. gence of the spring; b, profile of resulting hopper. 

POST-WISCONSIN VALLEYS. 

NATURE AND EXTENT OF EROSION. 

Little work has been done in post-Wisconsin time by the larger streams of Long Island other 

than local widening of their valleys, for their channels had already been extended to or below 

the level of the sea when the JVisconsin ice sheet retreated be,fore the opening of the present 

period. The principal recent changes have been accomplished by subordinate agencies, the 

chief of which are "spring sapping" and rivulet erosion, the former represented by numerous 

amphitheaters and the latter by short ravines. and gullies in the bluffs and by 

small notches in the older valley floors. 

FORMS OF THE VALLEYS. 

Amphitheaters.-Wherever a body of clay or other impervious substance 

underlies a mass of porous material and comes to the surface at or near drainage level (a, fig. 41), there is formed a series of springs bften perennial and 

FIGURE 42.-Piauofhop- copious in volume. At such places part of the overlying incoherent sand is 

per or amphitheater at almost always carried away, the action being limited at first to the immediate au early stage. vicinity of the point of emergence of the spring ·ca, fig. 41) but extending 

later farther and farther back until :finally a great hopper-shaped excavation or amphitheater 

results, as shown in profile in :figure 41 and in plan in figure 42. 

In the early stages the hoppers or amphitheaters are of nearly circular outline, but as the 

sapping progresses the erosion tends to become uneven through the influence either of inequalities in the-underlying in1pervious stratum, or of variations in the character of the material in 

which the hopper is cut, or of other causes affecting the distribution of 

drainage lines. As a consequence of unequal sapping, erosion goes on 

faster at son1e points than at others, and an unsymmetrical amphitheater soon results .(:fig. 43). The irregularity continues to increase until a 

normal drainage system is produced. Few if any 'Such systems, however, have been developed on Long Island in post-Wisconsin time. Hoppers 200 to 300 feet in diameter and 100 feet or more deep are seen at 

many points along the north .shore, especially from Wading River eastward to }.1attituck Inlet. . FIGURE 43.-Plan of transitional 

Notched cli+f8.-The notched cliffs are produced by an agency 'vork- form between a hopper and a '.11 normal dra~ge system. 

ing from above instead of fron1 beneath, as in the hoppers, the underlying clay and its attendant springs being absent. The notching is greatly facilitated by the 

incoherent nature of the deposits of the Manhasset formation, in which most of the notches are 

cut, but is retarded by the porous character of this material, which causes it to absorb the 

waters before they can unite and form streams of much vigor. Many of the notches start at 
52 GEOLOGY OF LONG ISLAND. 

close intervals and develop into a succession of sharp, V-shaped parallel ravines separated by 

narrow rounded ridges giving a serrate plan and profile to the bluffs at many places, especially 

along the edges of the lower bluffs in the eastern half of 

the island (fig. 44). 

Hanging .valleys.-Where the shore line has remained 

FIGURE 44.-Plan showing character of notching in unchanged for a series of years the ravines enter the sea· 

bluffs of the northern coast in eastern Long Island. 

at grade. As a whole, however, the coast is undergoing 

somewhat rapid erosion by the waves, a single storm not infrequently cutting several feet or 

even a rod or more into the base of the bluffs and leaving a large number of the ravines as 

hanging valleys with floors 5 to 10 feet above the beach (a, fig. 45). Where the stream erosion 

is slight the wave action may continue predominant for a long series of years or even permanently, in which case the action of the waves 

is cumulative and the valley enters at progressively higher points (b, c, and d, fig. 45) 

until perhaps only a slight notch at the upper 

edge Of the cliff remains ( e, fig· 45) • FIGURE 45.-Section illustrating the relation of height of hanging valleys 

As soon as the hanging valleys are formed to stage of erosion of bluffs. a, b, c, d, and e, Successive positions of · bluffs; a-e, floor of valley. 

by the cutting back of the cliffs their reexca- . 

vation by storm waters is begun, usually with a relatively narrow notch in their bottoms having 

a somewhat steeper grade than the older valley. (See fig. 46.) At the same time a steep fan 

is built up against the bluff at the point where the storm waters issue from it (d, fig. 46). 

Examples of hanging valleys are usually 

very numerous, especially within the first year or 

two after a severe northerly storm, and all the 

types described may generally be seen in a walk 

FIGURE 46.-Section illustrating the notching of hanging valleys. a, of a few miles along the beach, especially in the 

b, c, Original floor of valley; b, d, slope of channel of newly cut notch. • regwn east of Port Jefferson. The citation of 

the examples noted during the progress of the field work would, because of the constant changes 

in the bluffs, be of little value. 

Obstructed ravines.-Many of the ravines cut in the deposits of the north shore are more or 

less obstructed by materials brought in since their formation. Probably the most common 

cause of obstruction is the building of tt delta or fan across a ravine 

fron1 materials supplied by a tributary channel entering at a high -

angle. Such obstructions, however, are commonly due to local --------------·---

causes, such as a sudden increase of debris in a tributary, but are ~===~~=-~~~~~~~~=~ 

usually soon cut away. Another common cause of obstruction, 

• 1.1 • h h · · · th · f th · h FIGURE 47.-Section illustrating the espeCla y rn t e s arper ravrnes, IS e caVIng o e 1nco erent. obstructionofvalleysbylandslides. 

banks, letting down an irregular mass of sand, till, and other material (fig. 4 7). Several good examples were seen in 1903 in the region between Fresh Pond 

Landing and a point north of Riverhead. . 

R~filled ra.vines.-Many ravines have been partly refilled with deposits having the relations 

shown in figure 48. This refilling appears to be due to the waters becoming overloaded i.n the 

later part of the ravine's history, a condition apparently caused 

by a decrease of rainfall and run-off. In brief, it is assumed "=~·---'- ~- ~7_ __ - _..:.__-

-_-:-_;_-:._~._-.=.::.::.:::-.::.::.:_-_-_-=. that the original ravine was cut at a time of heavy run-off, per-

::= ---=-~ ---=-:-=._~.=::::_= 3?.. haps during a storm or series of storms, and that the filling has ----------:·-.- ----- taken place during a period of ordinary rains in which the run-off 

FIGURE 48.-Sectionofrefilledravineofthe has been insufficient to sweep the material to the sea. The difnorth coast. 

ferences in run-off are doubtless due to irregular and accidental 

local variations in precipitation and other conditions, rather than to any real climatic change. 

A single heavy and continued downfall of ra~ may at any time sweep the valleys clear of their 

fillings and even cut them deeper than they were originally. Valleys of this type are constantly 

changing. but examples can probably be found along the coast near Fresh Pond Landing. 
U S.GEOLOGICAL SURVEY PROFESSIONAL PAPER 82 PLATE XI 

TOPOGRAPHIC FEATURES OF LONG ISLAND, NEW YORK 

Scale az~oo 

1E3~=c~1~~~~=oE==:=:=:=:=:=:=:l~==============52~Ues Con.to<= :i:ntervaJ. 20 £eet . .Da;t;r.on., is ?ru?~ sea.- leveL. 

1913 
PHYSIOGRAPHY. 53 

INLAND SCARPS. 

PRINCIPAL EXAMPLES. 

Inland scarps of considerable prominence occur at several places on the island, some being 

of glacial and others of subaerial origin. The n10st important are the scarp facing the Connetquot outwash channel south of Smithtown Branch, those facing the valley between the Mannetto 

and I!alf liollow hills, and the one stretching along the south side of the Harbor Hill moraine 

west of its junction with the outer or Ronkonkoma moraine south of Manhasset Bay. (See 

Pl. II, in pocket.) The Connetquot scarp has been descrihed and its origin has been discussed 

in. detail on page 46. The scarps between the Mannetto and Half Hollow hills owe some of their 

features to stream erosion beginning as early as the close of Mannetto deposition, but the greater 

part of the valleys and ravines that now notch the edges of these scarps are clearly postManhasset, for they cut into and extend well below the surface of that formation. A further 

shaping, including the· planing away of projecting spurs, resulted from the action of the waters 

of the broad Wisconsin outwash channel passine- between the hills, and the final minor notching 

is the result of post-Wisconsin erosion. · 

THE GREAT INLAND SCARP OF WESTERN LONG ISLAND. 

CHARACTER. 

A well-n1arked scarp beginning at Lake Success, near the eastern boundary of. the Borough 

of Queens, where the outer or Ronkonkoma moraine is crossed by the inner or Harbor Hill 

moraine, extends westward in almost a· straight line to Fort liamilton at theN arrows, a distance 

of about 20 miles, with.a height of 60 to 100 feet above the outwash deposits bordering it on 

the south (Pl. XI, A.). An examination of its face shows the surface material to be n1ainly 

till, some sections nea:r the top of the bluff containing 20 to 30 feet or more of this material. 

Nevertheless records of wells put down a little back from the edge of the scarp generally show 

relatively little till, the drill soon passing into stratified sand or gravel, possibly a part of ·the 

n1oraine but more probably part of the 1\.fanhasset formation of which fine exposures north of 

the moraine are known to occur at this level. In Prospect Park, Brooklyn, more or less folded 

strata of sand and gravel, probably :Manhasset, have been exposed from time to time. It is 

believed that a complete cross section would show the bluff to consist mainly of stratified gravel 

of the :Manhasset formation, with a mantle of till varying in thickness from a few feet near Lake 

Success to 30 feet or more at points in Brooklyn, lying unconformably over its top and face. 

This till appears to be late Wisconsin, hence the scarp that it mantles must have been formed 

before that time. 

Additional evidence as to the age of the original scarp is afforded by the notches in its 

face. Fron1 Lake Success to the vicinity of Hollis the notches are generally small and simple 

with little branching, and such notches are characteristic of most parts of the scarp. Northwest of I-Iollis, near :Maple Grove, north of Woodhaven, and at several points west of East New 

York, especially near Prospect Park, Brooklyn, the notches are larger and· resemble the dendritic 

systems characteristic of drainage development. In fact, it seems fairly clear that such was 

their origin. They are not postglacial features, however, for they have ever;x: appearance of 

being clogged and partly obliterated by the deposition of till. 

In addition to the larger convexities, such as that north of Hollis, projecting swells of 

till and other material pushed forward by the ice occur here and there. .J. B. Woodworth 1 in 

describing the scarp says: 

West of Prospect Park the morainal front maintains its lineal course toward New York Narrows, but with a rather 

bulging frontal slope composed of stratified gravels. As seen in pits open in the season of 1900 these stratified gravels 

rise up steeply from the northem margin of the frontal plain, then bend downward into a large kettle hole in the 

deposit. The attitude of the beds suggests frontal shoving .on the part of the ice. 

1 Bull. New York State Mus. Nat. Hist., No. 48, 1901, p. 649. 
54 GEOLOGY OF LONG ISLAND. 

ORIGIN. 

That the original scarp was cut in deposits antedating the later Wisconsin drift (probably 

in the :Manhasset formation), that it is the result of erosion, that it was subsequently buried 

by a mantle of late Wisconsin till, and that it has suffered little subsequent erosion, seem clear . 

. The fact that its origin antedates the deposition of the latest drift explains why the scarp lacks 

the abruptness that would be expected if the cutting had been post-Wisconsin, and why no 

beaches or terraces have ever been found. The range in elevation of the base of the scarp· 

from 240 feet near Lake Success to 60 feet near East New York, which has always been a 

· stumblingblock in· the way of accepting the theory of its recent marine origin, is due to the 

natural slope of the outwash plains built agajnst. it, the line of contact with these plains being 

in no sense a warped 'shore line. 

The origin of this scarp appears to be clearly indicated by its topography, every feature 

of which is duplicated elsewhere on the island under conditions apparently admitting of the 

absolute determination of origin. The original scarp differed in no way from the bluffs at 

dozens of poin.ts on the north· shore, and the -drift-covered face and partly filled valleys have 

counterparts at many places. This is strikingly brought out by the maps given on Plate XI, 

A and B, which represent respectively a part of the morainal scarp near Creedmoor, and a part 

of the north shore near Miller Place, e~st of Port Jefferson. The same steep bluffs. with minor 

indentations are seen in each locality, and the valleys cutting them are almost identical in. 

character. The only difference in the topography, in fact, is the slightly steeper face at the 

Miller Place locality, due to the fact that there is no coating of till on· the face of the bluff, 

which is being rapidly cut by the waves at the present· time. There is little reason to doubt 

that the inland scarp under discussion is, in its main features, of. ~arine origin but has been 

modified by late drift. (See Pl. XI, D.) There seems to be no ground for regarding it, as 

some have, as a morainal front, for it has few of the characteristics of a moraine except in its 

most superficial features. 

How high the lan~ stood when the scarp was formed can not be told. From the depth of 

channels in the vicinity of the island (see p. 59), it is known that the land stood considerably 

higher in relation to the sea in the Vineyard interval than at present. The fact that Cretaceous 

formations are found at a depth of about 100 feet, or about 25 feet below sea level in a well 

in front of the scarp at Hollis, shows, however, that unless the mass encountered represents an 

offshore island, the land could not have stood more than 25 feet higher than at present. 

SHORE BLUFFS. 

There is hardly a point on Long Island at which the highlands reach the coast where th~ 

shore is not bordered by bluffs, this being true of the bay~ and harbors as well as of the exposed 

coast line. The condition of the bluffs varies greatly from place to place, however, all gradations 

being observed from nearly vertical cliffs such ;:ts border the south coast west of :Montauk light 

to relatively gentle slopes (25 ° to 35 °) completely covered with trees. On the open coast 

. probably four-fifths of the bluffs are free from vegetable growth, and perhaps a tenth are 

sufficiently free from talus to admit of the determination of their composition and structure 

from top to bottom~ The remainder are clothed with grass or trees or artificially covered. 

In the harbors. about half of the cliffs are covered with vegetation and half free from it. Harbor 

cliffs are, however, seldom free from talus, but even in the_ talus-covered cliffs the general 

structure. can usually be made out by a little digging. · 

The condition of the bluffs often changes materially within a short time. The whole line 

along a coast may be modified by a single ·storm, which in some places eats into the bluffs a~d 

-elsewhere throws up barriers of sand or gravel in front of them, according to the direction of 

the wind, the angle of impact of the waves, and the nature of the currents set up at the time. 

The barriers built up along the beaches in front of the bluffs persist until they are removed by 

storms or currents from other directions than those of the storms· which formed them. Some 

of them last for many years-long enough for the cliffs behind them to become covered with 

grass or even forests-but sooner or' later the cutting begins again and the cliffs are under-
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 82 PLATE XII 

GENERAL VIEW OF GREAT LANDSLIP AREA AT BROKEN GROUND, NORTHEAST OF NORTHPORT. 

Photograph by G. N. Knapp. 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 82 PLATE XIII 

.A. 

B. 

BROKEN GROUND LANDSLIP AREA, NORTHEAST OF NORTHPORT. 

A. Inn er scarp and tilted block. B . Upturned Cretaceous clays at base of landslip mass. 

Ph otographs by G. N. Knapp. 
PHYSIOGRAPHY. 55 

mined, landslides take place, and earth and tree trunks are m!ngled in confused heaps. (See 

"Landslides," below.) 

The cliffs are best preserved where coherent materials, such as the Gardiners clay, Jacob -

sand, and :Montauk till members of the Manhasset formation outcrop in the bluffs (Pls. XIX, 

B, p. 114; XXII, A, p. 136), and are least well preserved in the sands and gravels of the Manhasset (Pl. XX, p. 116). At the time of the examination of the shore line in 1904 the best 

exposures were on Gardiners Island, on Robins Island, and on the south coast of :Montauk from 

Napeague Bay to the lighthouse. Fine ~xposures 'were also found ·on the south side of Great 

Peconic Bay, on the two .large necks east of Sag Harbor, and especially along the north coast 

from Port Jefferson to Orient Point. Good exposures were seen northeast of Northport and 

on Eaton and Lloyd necks. West of Oyster Bay, aJthough there were a few good exposures; 

as at Rocky Point and on th_e east side of ·Hempstead Harbor, the bluffs are prevailingly low 

and are in many places artificially covered. The south shore, except the :Montauk Peninsula 

and the part of Shinnecock Bay south of the Shinnecock Hills, is essentially free from cljffs, 

although it has some bluffs 4 or 5 feet high. 

LANDSLIDES. 

Landslides may be ranked among the conspicuous features of Long Island, occurring, as 

would be expected, at many points on the steep· bluffs of the north shore. Some of them represent a mere slipping of the surface of the bluffs, whereas in others the land is affected for many 

hundred feet back fron1 the shore (Pl. ·xii). The slides are of a number of differ~nt types and 

are due to a variety of causes, the more important o~ which are noted below. 

CAUSES. 

Work of waves.-The action of waves is the direct cause of many of the landslides of. 

the island and the indirect cause of" most of the others. The whole north shore, the shores 

between the flukes, and the south shore between Montauk Point and N apeague Beach are 

exposed to the full action of the waves, which during storms, cut rapidly into the bluffs. When 

the cutting begins in the softer material, such as the Manhasset formation, the talus that has 

gradually accumulated since the last preceding storm commences to slide downward and is 

soon removed by the waves. The undisturbed drift itself is then attacked, and this, being generally loose and uncemented, crumbles as soon as a vertical face of a few feet is produced, often 

settirig the entire face of the sandy bluff in motion, tilting or overturning the trees, shrubs, or 

pla:nts that may have obtained a foothold upon it. A similar result. often follows stream erosion 

on the sides of some of the small but sharp ravllies of the north shore. 

If the 1naterial is till, especially the partly cemented Montauk type, the erosion is somewhat 

different. The 1naterial does not crumble rapidly, and the waves often 1nake progress only by 

tearing it away bit by bit until they produce a vertical or even·overhanging·face. Faces overhanging as 1nuch as 3 or 4 feet have been observed. When this stage is reached a new process, 

which may be called scaling, begins, the material peeling off in verticallaye~s or scales. Some 

of these layers are thin, but in places vertical slabs, the largest 20 feet or more high and 1 or 2 

feet thick, become detached. The most typical examples of these slides, if they may be called 

slides, are seen at Montauk Po.i.nt. 

lVork of springs.-The 'action of spring sapping on Long Island, which is a very prevalent 

cause of landslides, was described as long ago as 1843 by Mather. Springs act in t'Yo waysby adding water to the finer sands and converting them to quicksands and by actual erosion by 

the streams proceedn1g from them. Commonly both processes go on together.. · 

The gravels of the north shore are saturated by waters that ordinarily reach the sea betw~en 

high and low tide. by seepage without appearing at the surface elsewhere. Under these usual 

conditions few or no slides seem to be produced, for the water table is at some distance below 

the beach, and the quicksands, if any are formed, are prevented from escaping by the overlying 

material. But where an impervious layer holds the gro.und water in the bluff at a level higher 

than the beach, the sands may be changed to quicksands and flow seaward, allowing the ·over- · 

lying 1naterial to sink and producing htndslides of considerable size. The action is generally 
56 GEOLOGY OF LONG ISLAND. . . 

localized and produces hopper-shaped instead of lineztr slides. At this stage the water of the 

spring begins its erosion, carrying the material brought down by the slide to the beach while 

new slides bring down additional masses to take the place of the first. The pronounced amphitheaters on the north coast and many of the short, sharp valleys are produced in this way. 

Movements of clays.-The slides produced by the flowage and slipping of clays are by far 

the most conspicuous slides on the island, because of the considerable areas they cover and the 

confusion of the resulting topography. Many of the clays when wet are very plastic, and there 

is probably considerable flowage of those in the steeper bluffs under the weight of superincum-, 

bent deposits, although this is difficult to prove because of the absence of good cross sections. 

If not the cause of the landslides it is certainly. an effect; for there are many places where the 

plastic clays have been pressed out upon the beach in contorted masses, as shown in Plate XIII, B. 

I 

I 

I 

I 

I .;o ,/ 'c 

,=-~~~--------- FIGURE 49.-Section showing the nature of displacement in the larger landslides and the ori-

. gin of the scarps shown in Plates XII, XIII, 

A, and XIV, A. a, Original proftle; b, profile 

after slipping; c, slipping surface. · 

The sliding of the layers of clay o.n their bedding planes 

is also doubtless an important ·cause of landslides, but here 

also no evidence has been found to show to what extent 

this movement ~ctually takes place. Sliding may occur 

also along curved fractures, as shown in figure 49. Such a 

movement is suggested by the conditions shown in Plate 

XIII, A, although there is no reason why either of the 

other causes should not have produced the same effect . 

The sliding of sand beds over wet clays has been suggested 

as another cause of slides, but observation on Long Island 

seems to. indicate that ordinarily no such slipping takes place. In every clay slide observed 

the clay beds themselves seem to have moved, as indicated by the contorted structure they 

have assumed. 

DETAILS OF LANDSLIDES. 

The Broken Ground slide, the largest on the island (1904), is situated on the Sound shore, 

3 miles northeast of Northport and 1 mile north of Fort Salonga. 1 The north face of the hill, 

which has an elevation of 100 feet, has been converted by the slides into a confused jumble of 

earth masses and prostrate trees. On passing northward over the crest one suddenly comes to a 

fault scarp varying in height from 5 feet at the ends to 30 or 40 feet at the center (Pl. XIV, A). 

At the base of the scarp is a broad shelf ~0 yards across, representing the surface that was dropped 

by the fault (Pl. XIII, A). Beyond this is a succession of slip faults separating narrow tilted 

blocks, the whole grading off to the more confused earth heaps at the base (Pl. XIII, B). In 

1904 many of the faults were still open to a depth of 5 to 10 feet. The whole disturbed area 

has a length of nearly half a mile and a width between an eighth and a quarter of a mile. 

The other landslides on the island are relatively small, only the faces of the bluffs commonly being affected. It is obvious that any storm would be likely to remove old slides of 

this character and produce new ones, hence detailed descriptions would have little value. It 

may be said, however, that extensive slides inay be looked for at any point where clays are cut 

by the sea. These localities are indicated op. the geologic map (Pl. I, in pocket). Among the 

places where more or less definite slides were observed in 1904 may be mentioned the west shore 

of Eaton Neck (where Cretaceous clays outcrop); Woodhull Landing near Miller Place, west 

of Hulse Landing, Jacobs Point, Luce Landing, and Jacob Hill (Gardiners clay).; Oregon Hills 

and Mulford Point (till). · - SUBMARINE FEATURES. 

LONG ISLAND SOUND. 

The great Sound valley.-After the close of Cretaceous deposition in the Long Island region 

there was, as has been seen, an interval of nondeposition during most of Eocene time. The 

extent of the uplift in this interval, if any, and the amount of erosion are not known, but it does 

not appear to be represented by any great unconformity. During Miocene time the land, at 

least in the southern part of Long Island, was below sea level, and enough deposits were laid 

t Incorrectly located by Veatch (Prof. Paper U. S. Geol. Survey No. 44, Pl. VII) as northeast of I;Tuntington. 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 82 PLATE XIV 

A . MAIN SCARP AT BROKEN GROUND LANDSLIP AREA, NORTHEAST OF NORTHPORT. 

Photograp h by G. N. Knapp . 

B. CRETACEOUS DEPOSITS ON LLOYD NECK. 

Showing composition and struct ure. P hotograph by G. N. Knapp. 
PHYSIOGRAPHY. 57 

down to bury in large measure the erosion topography developed in the Eocene epoch .. It is 

believed that up to this time the Cretaceous deposits existed as an essentially continuous sheet 

with its northern border overlapping upon the crystalline rocks of t~e Connecticut shore, and 

that the Miocene deposits rested on the Cretftceous with their shoreward 1nargin somewhere in 

the southern third or half of Long· Island. 

In the Pliocene epoch the region was greatly reduced by erosion, in which both streams and 

the ocean took part. A. C. Veatch 1 believes that during the early part of this period (preLafayette) I-Iousatonic and Connecticut rivers cop.tinued to flow southward across the Coastal 

Plain but developed, through the agency of tributaries along the contact of the Cretaceous with 

the crystalline rocks, more or less marked lateral valleys with northward-facing scarps. These 

lateral valleys were partly filled but not obliterated by the Lafayette deposits, but the narrow 

valleys leading southward through the ridge are considered by Veatch to have been 1nore nearly 

effaced. The post-Lafayette uplift he apparently regards as accompanied by a tilting toward 

the southwest, which caused Housatonic and Connecticut rivers to· be deflected westward, 

passing across the site of Long Island in the vicinity of Jamaica Bay near the west. end and, 

after uniting with the I-Iudson a few miles beyond, running southeastward in what is usually 

known as the submarine Hudson channel. Veatch's maps show that he supposes this course 

to have been 111-aintained after the Mannetto deposition, amounting to 300 or 400 feet or more, 

and to have been deflected only after the deposition of the Manhasset formation (Tisbury of 

Veatch). To the erosion by the streams mentioned, acting through this long period, V catch 

refers the development of Long Island Sound. 

T'o the writer the history seems to be somewhat different. After the post-Miocene uplift 

the strean1s, as stated by Veatch, -probably continued southward across the Coastal Plain to the 

ocean and very likely developed lateral valleys along the contact with the crystalline rocks .. 

Any opinion as to what happened in the Long Island region in Lafayette and post-Lafayette 

time 1nust be entirely speculative, for no Lafayette deposits have been identified, and there 

is no evidence yet available for distinguishing between the post-}.1iocene and post-L.afayette 

erosion periods. 

'rhe Mannetto deposition amounted to more than 300 feet and possibly·more than 500 feet 

and in central Lm1g Island appears to have buried all the older deposits, with the possible exception of those 01r I-Iigh Hill, south of Huntington, where, though ;nothing but drift shows at the 

s~rface of the hill, the topographic features suggest that it may have a core of Cretaceous material. 111e Mannetto deposits would have completely obliterated any valley across Long Island 

that Inight have existed. If the drainage in post-Mannetto time took the course indicated by 

V catch, it must have marked the beginning of a new cycle that was entirely independent of the · 

earlier and did not inherit the courses of its streams. 

The distribution and elevation: of the Cretaceous deposits of western Long Island indicate 

that, in all probability, no conspicuous valley with its bottom much below the present sea level 

. was ever formed across the island in the J amaica-J ameco region. These deposits appear to be 

above sea level fr01n a point east of Smithtown to a point north of Jamaica. At Whitestone 

they are less than 20 feet below sea level, and at College Point they appear to be less than 85 

feet below sea level. The distance between the point of observation north of Jamaica and that 

at Whitestone is 2 miles, and that between Whitestone or College Point and the outcrops of 

crystalline rocks on the mainland is 1 mile. The intervening channel is only about 60 feet deep. · 

There is, therefore, no room for any but a narrow and correspondingly shallow channel through 

the island at this point, there being no break comparable in size to the broad Sound supposedly 

due to erosion by the same streams. It would be strange if the stream that in its upper 

part eroded a valley from 10 to 20 miles wide should hav~ a valley only 1 or 2 miles in width 

near its mouth. 

The Sound is broadest at a point southeast of New I-Iaven, where it has a width of over 20 

1niles. From this point it tapers gradually westward until only the narrow East River separates 

I Prof. Paper U, S. Geol. Survey No. 44, 1906, pp. 28-32. 
58 GEOLOGY OF LONG ISLAND. 

Long Island from the mainland. A more significant feature, however, is the similar form of 

the area inclosed between the mainland and the Cretaceous remnants lying above sea level on 

the island. At Eaton Neck the breadth of the strip between the Cretaceous boundary and the 

crystalline rocks is 8 miles, at Lloyd Neck 7, at Glen Cove 5, and at Elm Point 3 miles. At 

Whitestone the Cretaceous, which is here only 20 feet below sea level, is only about a mile from 

the' crystalline rocks. If normally developed by subaerial erosion, such a valley could be produced only by a stream system dra~ing eastward. 

That the Sound .is in the main the result of such erosion rather than of ice scour is probable, 

as the Pleistocene deposits of Long Island, although derived principally from the Sound, would 

not obliterate .it if returned. Moreover most of the drift above sea level in the eastern part of 

the island appears to have been derived not from the Cretaceous deposits but rather from the 

mainland or from older glacial deposit·s lying in the Cretaceous trough. This trough is not the 

. result of ice erosion, as .is shown by the absence of corresponding glacial accumulations, and the 

great depth to the Cretaceous surface (5l55 feet below sea level in a well at Greenpor.t) n1ust therefore be referred to stream work. Other well records throw light on the eastward deepening 

of the buried Cretaceous valley-the Sound valley, as it may be.called. · 

In a map based on such records Veatch 1 shows the Cretaceous to be at or within a few feet 

of sea level in the vicinity of the north coast from College Point eastward to the v.icinity of Stony 

Brook. A well record, as stated above, shows it to be about 550 feet below sea level at Greenport, but at Fishers Island, still farther east, the top of the Cretaceous seems to be only· 260 

feet below sea level. None of these points, except perhaps the Greenport well, are in the present Sound valley, and there is no means of estimating the depth of the old valley except by 

prolonging northward the observed decline of the Cretaceous surface, as brought out by well 

records, and the present depth of the Sound, a method which is of course far fron1 satisfactory. 

In the hills north of Old Westbury this surface has an elevation of about 230 feet. Thence 

it declines northward, being slightly below sea level at the coast. The same rate of fall would 

give it a depth of at least 100 feet in the center of the Sound. In the Mannetto Hills it is elevated 

about 300 feet, and it declines to sea level at Lloyd Neck, a rate which would carry it to 150 

feet below sea level in the Sound. The water as a matter of fact is more than 100 feet. deep 

at this point. At Westhampton the Cretaceous is about 150 feet below sea level, whereas at 

Riverhead, 8 miles to the north, it was not recognized in a well 300 feet deep. At Bridgehampton it seems to have been encountered about ·75 feet below sea level, although 12 miles 

farther north, at Greenport, it was reported about 550 feet below sea level. 

There se~ms, therefore, to be a broad buried valley in the Cretaceous surface in the Sound 

region, having a width of a mile or two near the west end of the island and opening· out eastward to a width of about 20 miles near New Haven. The valley seems to deepen eastward from 100 feet or less near College Point to at least 550 feet in the vicinity of Greenport. Its southern rim is pretty uniformly from 300 to 400 feet higher than the lowest 

point of the valley. The shallowness of the Cretaceous o:p. Fishers Island would seem to 

indicate that the axis of the valley passed south of this point. 

The present valley of the Sound seems to be due principally to strean1 erosion, assisted, 

however, by a certain amount of jce scour. It appears to have been cut entirely in the unconsolidated Pleistocene and Cretaceous deposits, there being, so far as known, no corresponding 

depression in the underlying rock surface nor other evidence to support the theory of limestone 

solution advanced by F. J. H. MerrilP on the basis of the composition of. the clay.· 

Later channels.-The bottom of Long Island Sound as a whole is remarkably even, in most 

places sloping gently southward from the Connecticut shore at the rate of 10 or 20 feet to the 

mile for about two-thirds of the way acro.ss the Sound, and rising somewhat more steeply to the 

Long Island coast. The level bottom is, however, as was long ago pointed out by Dana, 3 inter1 Veatch, A. C., op. cit., Pl. III. 

2 Annals New York Acad. Sci., vol. 12, 1900, pp. 113-116. 

a Trans. Connecticut Acad. Arts and Sci., vol. 2, 1870, pp. 65 et seq.; Am. Jour. Sci.,3d ser., vol. 10,1875, pp. 280-282; vol. 40,1890, pp. 425-437. 
PHYSIOGRAPHY. 59 

rupted by a number of more or less channel-like depressions. The most conspicuous of these 

extends eastward from a point about north of Oyster Bay and is frorri 25 to 50 feet deeper than 

the surrounding bottom (fig. 50). At a point north of the head of Great Peconic Bay it bends 

slightly southward and is lost in the shallow water of the Long Island coast. Dana considered 

that it passed across the site of 

the island near Mattituck, but 

of this there is little evidence, as 

the. present valley at this.point 

·is or' other origin. (See p. 28.) 

Another channel-like depression starts a few miles northwest of the point where the first 

ends and· extends northeastward to a point beyond Little 

Gull Island, where it divides, 

one branch passing south and 

the other north of Valiant Reef. 

In this vicinity depths of 50 to 

55 fath01ns, or 300 to 330 feet, 

are recorded, although on each 

side of the channel the water 

is relatively sha1low. East of 

Valiant Reef there are four 

branches; one passes north of 

Block Island and the others 

start in a southeasterly direction and are lost in the shoals 

north and northeast of Montauk Point. This digitate sys- . 

tern of channels converges westward, and if it is the work of 

streanis would indicate a west-

\varcl drainage. The digitate 

portions occur only in what is 

known as the "Race," a locality of severe tidal scour, and 

their fonn may have resulted 

fro1u tidal actio'n. It is djfficult, however, to account for 

the channels in the bro~der 

parts of the Sound in this way, 

for they do not follow lines 

of especially strong currents. 

Moreover, the general relations 

as brought out in figure 50 

strongly suggest stream origin. 

l.f they were cut by s_treams 

they are, in all probability, to 

0 

..... 

"' 

~~-~--~------~~~--~~~~~~~~~~~w·~ 

'~·-

be referred to the Vineyard erosion interval, as they are at a much higher level than the 

post-Mannetto land surface, which was developed at the last preceding stage of uplift, and 

there has been no post-Vineyard elevation sufficient to account for their depth. An earlier 

ti1ne than the Vineyard is also precluded by the tremendous ice scour and subsequent deposition 
60 GEOLOGY. OF LONG ISLAND. 

characterizing the Montauk ice invasion. The point of outlet of the system, if one really 

existed, is unknown, but the absence of any break in the :Manhasset deposition indicates thfl,t 

the outlet could have been only at the extreme west end of the island, probably beneath the 

present lowlands in the vicinity of Long Island City or 

even along East River. 

" Starting at a point 7 miles 

east of Montauk Point, or a 

little over halfway to Block 

Island, a submerged channel, 

50 feet deep in places; extends 

southeastward for nearly 10 

miles. Its upper part is only 

about a quarter of a .mile 

wide, and it is characterized 

by swings and other features 

of a true stream channel. It 

seems to be lost at a depth 

of 20 to 25 fathoms, hence at 

the time of its formation the 

land apparently stood 120 to 

150 feet higher. A shallow 

depression connects this 

channel with one of the depressions southeast of the 

Race, but it seems to be 

nothing more than a tidal 

connection. · 

Conclusions.-The excava:... 

tion of the Cretaceous deposits began in the post-Miocene period of erosion, but 

whether the valley then 

formed persisted through thcd 

Lafayette accumulation (if 

any took place in this region) 

and the Mannetto deposition 

is not known. The valley or 

its successor appears to have 

been completed, however, in 

the post-Mannetto stage of 

erosion. It was partly :filled 

during the J ameco, Gardiners, Jacob, and Manhasset 

stages of deposition but was 

10 .1o zo Miles not obliterated, and at the 

FIGURE 51.-Map of the submarine channel and canyon of Hudson River. By J. w. Spencer. close of the Manhasset stage 

Figures indicate depth in feet. it seems to have been occupied by a westward-draining river system, which excavated· the submerged channels. At the 

same time a well-defined channel leading southward between Montauk and Block Island was 

formed. In the last ice advance the valleys were partly :filled and otherwise modified by the 

actio.n of the overriding ice and by the accompanying deposition, and in recent time tidal 

scour has ~one .much to change the character of the cham1els. 
PHYSIOGRAPHY. 61 

SUBMARINE CHANNELS OF THE HUDSON. 

GENERAL CONDITIONS. 

Channel of the continental shelf.-Since the northern part of the continental shelf was first 

charted the so-called submarine channel of the Hudson has aroused much interest among both 

geologists and geographers, and many papers' describing it and discussing its origin have been 

ptlbljshecl. It n1ay be described briefly as a submerged valley leading .

1 ~ 

across the continental platform from a point a few miles east of Sanely ( ~ 

I-Iook southeastward to the margin of the shelf, 55 miles from the beginning ] } ~ (fig. 51). Beyond this margin a sharp canyon-like notch extends down ~ ~/ ~ 

the escarpment to a depth of a mile ,,'/ ~ 

;=-;:;-=-==:.:r------.-~-.,..,....-r.---.~- FEET or more below the surface of the sea. 1 § 

1000 The measurements of this channel ~l ( ~ 

given in the texts or shown on the f=Lk 

maps by different writers do not en- =~~ 2000 

3000 tirely agree with one another, hence ~~~ 4000 ··~ it is necessary to cite authority for :~fri 

2 3 4 5 6 7 Miles the figures used. The depth of this tf~ FIGURE 52.-Crosssoctlonshowingrolationsofthebroad- channel at the Start is about 15 )~ er valleys and sharp canyon of tho submarine Hudson fathonls or 5 or 6 fathoms below .dfi 

channels. By J. W. Spencer. 1 :~~~;~: the adjoining sea bottom; at 10 miles ~:; ~~ 

out the depth is 8 fathoms below the surrounrling bottom, and at 20, 30, ~~~ ~, ;:"'~ and 40 miles about 15 fathoms. Beyond the 40-mile point, owing to a ~~~~~ 

steepening of the inclination of the platform, the slope of the channel c :!i' ~ 

being unchanged, the depth decreases and the bottom of the channel is ~ ~ [~!~ 

only about 8 fathoms below the level of the adjacent bottom at the 50- E ~ :::.r'o~ 

fathon1 contour, 45 1niles out. Immediately beyond this point, however, ~ ~1g1~~ is the beginning of the narrow but deep outer canyon or notch, which is ~ ~! ~~~!~ marked by an abrupt drop from 288 feet to 1,008 feet. This is followed by 1 J: ~:~:o?~ 

a gentle slope extending about 6 miles, at the end of which a second drop ~ ~HI%~ 

of about 400 feet takes place. A third drop of about 500 feet occurs about B t:~:~~ 

~2 1niles from the head of the canyon, the total·depth then reached being ~ Jk1:i~ 

about 2,292 feet, or about 2,050 feet below the continental platform. The ~ ·~ ··1!~ 

s9undings at this point (fig. 52), seem to indicate the presence of shelves ~· ;::t,~~ on the sides of .the canyon, at a depth of about 1,250 feet, the origin of § J :~ which is obscure. At 31 nliles the depth of the canyon has increased to o J!}{.~~:W 4,800 feet, or 3,800 feet below the surrounding sea bottom. Sp~ncer on .~,E;~~ 

his map (fig. 51) extends the canyon 43 1niles farther, to a depth of 6~poo ~~:~~)%f. 

feet, and indicates a shallower valley-like depression extending to a distance ·~~.I~.:.·.·.·_f 1.~Wf- of 71 1niles fron1 the head of the gorge, or to a clepth·of 9,000 feet, 2 but the ~ 

evidence for the extension beyond the depth of 4,800 feet does not appear ;r~f~~ to be conclusive. A section showing the relations of the various. channels ~.f •:·~~~' J.~~~:~l 

is given in figure 53. ~!~1f;~~;: ·~ 

Hudson River rock channel.-Intimately related to the submarine ] ~:~!~T-,.._,, ~ 

channel just described is the rock channel of I-Iudson River. That this ~ ~~ff~l)~,:! t:l 

recorded 

~:~:~~~s (1908) t~~:.:~l:~t~~:;~~~~L~~~E~:, is near Storm King Mountain, where ~Je~~~:~::;!;:F~:~ the bottom appears j ·~~.~~~==.·~~.,······::•.:=•.:.·:,: ~"' .. l>~.·.: .. [ 

"":_ 

:.~.·.:,:~.,~_.;,i,;·~,~.:.. -.- ~ g 

to be about 650 feet below sea level.8 At New York City the greatest. ~ 

depth recorded is about 300 feet, but there is room for a narrow gorge of greater depth between 

the soundings. Local erosion by ice to a depth of several hundred feet in the unusually hard 

I Map by J. W. Spencer, Am. Jour. Sci., 4th ser., vol. 19, 1905, p. 2. 

2 Spencer, J. W., op. cit., pp. 6--7. 

a Kemp, J. F., Am. Jour. Sci., 4th ser., vol. 26, 190R, p. 320. 
62 GEOLOGY OF LONG ISLAND. 

rocks near Storm King (although the t?Ofter rocks of the vicinity were relatively little eroded) 

does not afford a satisfactory explanation of the depth at this point, and it is equally unsatisfactory to assume that a warping of 350 feet has tak~n place between this point and New 

York. As examinations have shown that there is no other possible outlet for the old Hudson 

waters, it seems probable, although not certain, that a buried canyon at least 700 feet in depth 

must exist somewhere beneath the Hudson at New York City. 

HISTORY OF THE CHANNELS. 

Agencies offormation.-In considering the history of the submarine channels it is necessary 

to start with an assumption as to the agencies to which their origin is due. The principal 

basis for this assumption must necessarily be the form and course of the channels themselves. 

From the soundings, which have been taken at unusually. close intervals, probably closer than 

over any other submarine area of equal extent on our coasts, it is possible to contour the sea 

bottom with an accuracy comparable almost to that of topographic m·aps of the land surface. 

Not only are the broader features of the trough and the adjacent sea bottom brought out 

but many minor details, such as the accelerations of slope and the presence of shelves on the 

sides of the deeper canyons, are plainly shown. " 

The cross section of the submarine valley from Sandy Hook to the edge of the continental 

platform may be said to be practically identical in character with that of the normal streams 

which to-day cross the emerged portions of the Coastal Plain along the adjacent coasts. The 

sloping sides and nearly flat bottom of the submarine channel correspond with the similar 

gently sloping highlands that border the· terrestrial streams and their alluvial bottoms. Likewise, the curves and bends of the submarine_ channel differ in no n1aterial way from the similar 

sinuosities of the present Coastal Plain streams. 

The form and course of the trough, the presence of sand ~ the channel, although the 

surrounding sea bottom consists of clay, and the physical connection with the present Hudson 

River channel, except for the narrow bar of relatively recent deposits obscuring -the channel 

between Sandy Hook and New York, all seem to point to a fluviatile origin. Inasmuch as 

such a channel could not be shaped by any process at work in the ocean, so far as known to 

science, and as it has none of the characteristics of ·a fault depression, the writer has been 

led to ascribe tentatively the origin of the shallower channel to subaerial stream action when 

the land stood from 300 to 350 feet above its present level with reference to the sea. 

The origin of the deep canyon-like gorge extending seawa:rd from the outer end of the 

shallower channel seems to be less certain .. As shown by the map 1 (fig. 51) and section (fig. 52), 

the gorge exhibits, both as regards its course and the character of its cross section, the normal" 

characteristics of an erosion notch cut back in the mesa-like edge of the continental platform, 

and the sharp drops or falls at- intervals in its bottom are equally characteristic of young erosion. 

Furthermore, it seems to represent the continuation of the inner, shallower channel, which 

the writer considers to be due probably to stream erosion. Like the inner channel, it appears 

to have none of the characteristics of a fault fissure. It can not be considered a depression 

such as might be caused by the slumping of the materials along· the steepened margin of the 

c'ontinental shelf, for such a depression would necessarily be approximately parallel with instead 

of at right angles to the margin of the platform. Submarine scour as a cause of canyon cutting 

appears to be entirely out of the question. 

The theory that the gorge was excavated by stream erosion would involve an elevation 

of several thousand feet at the time of the erosion -not less than 4,806 feet being required 

by the depth of the floor of the lower part of the gorge, as shown in figure 51. Cl'he writer, in common with most other geologists, is loath to· acknowledge the occurrence of any such elevation 

at this point in Pleistocene or late Tertiary time. It is ·not impossible, however, that in the 

reaction from· the belief in great and rapid oscillations of level, held by many geologists a few 

1 It should be stated that the character of the channels was not determined from the ·few soundings shown on the map, but from ·a very large 

number of soundings, which could not be indicated readily because of the small scale of the drawing. 
PHYSIOGRAPHY. 63 

years ago, the pendulum has swung too far, and the present tendency may be to minimize the 

evidences for such oscillations. Notwithstanding the violent assumption of elevation involved, 

the forn1 and character of the gorge itself appear to be more nearly those which normally result 

frotn stream erosion than from any other known agency. The writer does not wish to be considered as advocating the assumption of excessive elevation in general, and especially he does 

not wish to advoeate it as an explanation of the broad troughlike submarine depressions of this 

and other localities that· have been cited by some writers as erosion features, and even in the 

present instance he would· go no further than to point out the apparent significance of the 

channel features. 

The principal features to be accounted for in a consideration of the history of the channel 

and canyon are (1) the rock gorge of the present Hudson River, presun1ably cut to a depth 

of about 700 feet belowsea level; (2) a broad outer depression, in the bottom of which the 

canyon notch is found; (3) the cutting of the deep outer canyon; (4) the filling of the first 

deep channel of the Hudson; (5) the cutting of the present shallow, upper submarine channel; 

and (6) the partial filling of the inner end of the upper channel. 

Cutting of the 7001'oot channel.-The rock gorge of Hudson River proper, which k 

assu1ned to be about 700 feet deep in the vicinity of New York, appears to be filled solely 

with Pleisto0ene materials, as indicated by the Storm King and other borings; hence, unless 

earlier beds had been deposited. and subsequently removed by glacial ice, its cutting is 

to be referred to a date later than that of the deposition of the latest ·Tertiary beds in this 

region: It was probably cut at a much lat"er date, for the Mannetto gravel (pre-Kansan ~), 

which accun1ulated to a height of 300 feet above the present sea level in western Long Island, 

seems to have been orig4lally continuous with the Bridgeton formation of New Jersey, which 

is built up to at least 200 feet above sea level in the northern part of that State. After the 

deposition of the gravel, however, there was a period of uplift and erosion in which the Mannetto was cut to a depth of at least 300 feet below sea level, as shown by the depth of the 

buried Jmneco channel of Long Island. The great length of this P.eriod of erosion, indicated 

by the ahnost con1plete removal of the thick Mannetto gravel from the Long Island region, 

is in harmony with the time required for the cutting of the Hudson River rock gorge. Inasmuch 

as there are in the later deposits no unconformities that would indicate prolonged elevation 

of si1nilar degree, it seems that the date of -the cutting of the rock channel may be referred 

with n. considerable degree of certainty to· the long post-Mannetto (Aftonian ~) interval. · 

It is not beyond the limits of possibility, however, that the 700-foot channel may be somewhat , older than the post-M:annetto and pre-J ameco. Although the Mannetto gravel and 

Bridgeton fonnation were presumably continuous n.nd stood at a considerable elevation above 

the sea in the region of the upper part of the present channel, it is not impossible that they . 

were in part glacial outwashes fron1 localized centers of dispersion, and in that case a gap 

might l~ave been left in the region of New York City in which a pre-Mannetto channel might 

have persisted. 

The channel began at some point well above New York City, for soundings to a depth 

of 650 feet in its fillings have been n1ade as far north as Stonn King Mountain, 50 miles above 

the city.1 It extended southward and southeastward probably to the edge of the continental 

shelf. Possibly the land along the northern part was more elevated than that near the coast, 

and the excavatio.~l was therefore less near the sea than farther up the valley. That the gorge 

was excavated to a depth .of more than 300 feet in the vicinity of New York City, however, 

has been established by borings, and a channel of at least that depth, if not of 700 feet, apparently Inust be assumed as .having been formed across the continental shelf. 

The broad outer depression.-Well-marked shelves occur at intervals on both sides of the 

canyon portion of the submarine channel, from the inner to the outer end. (See fig. 52, p. 61.) 

They" are not continuous,. however, the total space occupied being only about half the length 

1 Kemp, J. F., Our knowledge of the filled channel in the Hudson of the Highlands and the submerged gorge on the continental shelf: Science, 

new ser., vol. 29, 1909, p. 2i9. 
64 GEOLOGY OF LONG ISLAND. 

of the gorge, and some of those at up-channel points are lower than those at down-channel 

points. Inasmuch as their absence can not be accounted for by incompleteness of soundings, 

it does not seem likely tha't the shelves represent an old valley marking a separate epoch in the 

history of the channels, as their appearance at first suggests. 

The outer canyon.-The narrow, steep-sided, and deep outer canyon, although it is the most 

marked feature of the submarine channel system, would appear to require, if due to stream 

erosion, but a relatively short period for its formation, as compared with that needed for the 

excavation of the long rock gorge of the Hudson. This fact is emphasized by the great drops 

or falls in its bed, which could not exist had the period of canyon cutting been a.s long as that 

of the rock gorge. Probably it extended but little north of its present head, for there appears 

to be little evidence, to judge from the contours of the bottom, of anything more than a slight 

filling by later deposits. . 

So far as its observed features indica~e, the outer canyon might have been formed during 

either the post-Mannetto or the Vineyard interval of erosion. The soundings, however, seem 

to show that it was to some extent filled at its head by the great series of deposits that obliterated 

the continuation of the 700-foot channel; hence it must apparently be referred to the· same 

general period of erosion as that channel. If due to stream erosion at all, it must be referred 

to an elevation· of great magnitude, occurring at the close of the post-Mannetto erosion stage, 

but of so transient a character that the chief work of erosion consisted of a notching of the edge 

of the continental shelf, the land back of this point being but little affected. 

Obliteration of the earlier channels.-The post-Mannetto erosion was followed by a long period 

of deposition, as shown by the thick conformable series of deposits, including theJameco gravel, 

Gardiners clay, and Jacob sand. During this period, so far as known, the sea bottom in the 

vicinity of the channel remained constantly below sea level. The deposits, which have a 

thickness of 200 feet or more on Long Island, doubtless extended far to the south and largely 

buried the early channel. . The obliteration was probably completed by the outwash of the 

several stages of Manhasset deposition, including the Herod gravel member, the Montauk 

till member, and the Hempstead gravel member, which, although not having anything like 

the maximum thickness of 300 feet observed on the island, doubtless formed a sheet of considerable thickness. 

Gutting of the present upper channel.-The upper channel has a depth at its outer end of 

only about 350 feet, hence an elevation of the land of this amount will explain its formation. 

A~ no time break is indicated in the deposits of Long Island from the beginning of the Jameco 

to the close of the Hempstead deposition, and as there are nowhere on the island, even on 

the exposed coasts, any erosion channels referable to Wisconsin or post-Wisconsin elevation, 

the formation of the upper channel is most logically referred to the Vineyard interval of erosion, 

following the Manhasset deposition. The valleys in the Manhasset deposits, although somewhat modified and partly filled with Wisconsin accumulations, are known to extend some 

distance below sea level at many points along the north shore, indicating a higher position 

of the land than at present. These valleys, most of which mark small intermittent streams, 

naturally are not nearly so deep as the channel formed by the large Hudson stream, and in 

themselves indicate little as to the absolute elevation of the land, which is shown only by the 

submarine channels such as that of the Hudson. 

Filling of the upper channel.-The upper channel has been largely obliterated north of 

Sandy Hook, in part by the Wisconsin outwash and in part through the shifting of the sands 

by the littoral currents that now sweep along the coast. Its termination is somewhat indefinite, 

but where last recognized seems- to point toward Jamaica Bay. As the Manhasset deposits 

contain no gap or channel marking the position of any outflowing stream, the bend seems to 

be without significance, so far as Long Island is concerned, and is probably simply one of 

several bendsbetween Sandy Hook and North River at New York. 
GEOLOGY O;F LONG ISLAND. 65 

STRATIGRAPHIC GEOLOGY. 

METHOD OF MAPPING. 

The geologic n1ap accon1panying this report (Pl. I, in pocket) sets forth the present state 

of knowledge of the geology of Long Island so far as it can be represented with the data a~ 

hand. It is to· be noted, however, that here as elsewhere the glacial deposits of one type in 

places grade insensibly into those of another with no sharp line of demarcation. As boundaries 

are necessary they have been placed where they seem., all things considered, to bring out best 

the relations ·it. is desired to show, even if no exact line can be recognized in the field. Other 

real inaccuracies in detail have doubtless resulted fron1 the fact that a large part of the work 

,in the interior of the island was done before the topographic survey was .completed and without 

any accurate base, as a consequence of which many features could be located only with difficulty, 

if at all, on the new base. :More or less generalization has also beeri unavoidable because of 

the sn1all scale of the n1ap. 

This map shows the outcrops of the older Pleistocene beds as exposed in the bluffs in 1903 

and 1904, but as the condition of the exposures is constantly changing 1nany sections then 

observed will now be found to be destroyed and their places to be taken by exposures not then 

visible. There will also be much difficulty in distinguishing some of the beds in certain localities. For instance, the Wisconsin till and the Montauk till member of the Manhasset formation in some places so closely approach each other in character: that it is difficult to separate 

thmn when in contact, and they may appear as a single .unit. ·It is for this reason that the 

Montauk n1en1ber is not shown as occurring on the North Fluke, although in all probability it 

is present in the greater part of the length· of the bluffs. Again, .where the Montauk member is 

cornposed of reworked Gardiners day, it is almost impossible to distinguish it from the true clay 

except in the few places where granite pebbles have been incorporated in the reworked mass. 

In rnapping the outwash areas considerable generalization has been necessary, as all gradations between pure outwash and nearly p~re :Manhasset occur. · From the relations of· the two 

deposits it is to be expected that :Manhasset renmants n1ay be found here and there projecting 

above the areas shown as outwash, n.nd in some of the compound areas it may be difficult to 

detect any outwash. In fact, in n1any such areas the outwash is confined to a few channels. 

The geologic map is not strictly a lithologic map, the attempt being n1ade to bring out the 

history and relations of the deposits by rneans of a system of solid underprints representing 

the fundamental formations with overprints showing the superficial deposits. 

The 'dune areas are probably rnuch n10re extensive than is indicated, although the mantle 

is thin in places and the underlying deposits n1ay show through. Where the developments 

are weak the topography is ndt striking, and owing to the covering of forest and the absence 

of sections, the full extent of the old dune areas is very diffi.cult to determine. 

PRE-CRETACEOUS ROCKS. 1 

The basen1ent deposits of Lorig Island, originally considered in large part "Primitive" or 

cornposed fundan1ent_ally of metan1orphic rocks, have been successively classed or mapped _as 

alluvium, diluviurn, Tertiary and drift, and Cretaceous and drift. The early conception of 

simplicity of the drift has likewise been abandoned,· and where one formation was originally 

k,nown at least five are now differentiated and a complex series of events is recognized. 

' The pre-Cretaceous rocks of Long Island consist chiefly of pre-Cambrian gneiss with 

intruded dikes of granite and a little dolom!tic limestone. The gneiss, which is known as the 

Fordharn gneiss, is of a gray color and is made up of bands rarely exceeding 2 inches in thic:kness. The bands differ widely in composition, some being highly quartzose, others biotitic, and 

still others pegn1atitic. The banding stands at a very high angle and strikes about N. 25° E., 

being parallel ~th the course of that part of East River near Blackwells Island. The gneiss forms 

the western shore of Long Island from Lawrence Point southward to Newtown Creek. The 

dik_es occur as narrow intrusions of gray and reddish granite, usually parallel to the bandt For a more detailed description see Merrill, F. J. H., New York City folio (No. 83), Geol. Atlas U.S., U.S. Geol. Survey, 1902. 

:1.629°-14--6 
66 GEOLOGY OF LONG ISLAND. 

ing of the gneiss, and; being somewhat more resistant than the surrounding rock, have given 

rise to many of the islands of upper East River~ :Many small dikes occur in the vicinity of 

Rav~nswood, and there are pegmatitic masses of considerable size at Hunters Point. 

The dolomite, which is known as the Stockbridge dolomite, consists of alternating layers 

of coarsely crystalline dolomite andlimestone. It is well bedded, the layers standing at high 

angles and striking parallel to the gneiss. It is mapped by Merrill as a narrow band crossing 

the. neck west of Astoria and has been encountered in at least two borings in East River. 

Whether the Fordham gneiss is of sedimentary or igneous origin is not known, for the 

metamorphism that it has undergone has been suffici~nt to destroy all its sedimentary features, · 

if any ever existed. It is, as already stated, of pre-Cambrian age. The Stockbridge dolomite 

is clearly of sedimentary origin and is regarded as being of Cambrian and Ordovician age. The 

granitic and pegmatitic intrusions in the gneiss are younger than th~ dolomite, for they cut 

the Hudson schist (Ordovician), which overlies it, and are therefore of Ordovician or later age. 

These rocks have been compressed into close folds in which the beds stand nearly vertical, 

as shown in figure 54. There is considerable evidence that faulting has frequently taken place 

~ 

0: 

g 

-g 

:I: 

~ ~ " in the region, that 

~ ~ ., ~ ~ the structure of the 

~ 

a; 

a. 

Scale. 

1 

~ ~ -;;; (.!) ~ rocks is more complex 

~ -.; than is shown in the 0:: :I:• 

"0 .:. 

., ., :; > > 

0: 0: ~ 

~ ~ ~ 0 w w ..J 

2 miles 

sections, and that it 

may even have had 

a considerable influ- · 

ence on th~ topo-· 

graphic exprt)ssion 

of the East River 

region. 

~--~~----~--~--------~ 

FIGURE 54.-Sections from Hudson River to Long Island, showing in a general .way the folded.and eroded 

character of the bedrock underlying Loug Island. (After Merrill, 1902:) fgn, Fordham gneiss (pre-Cam_ 

brian); ess, Stockbridge dolomite (Cambrian and Ordovician); Sh, Hudson schist.(Ordovician). 

The m~tamorphic 

rocks are seen at the 

surface only in a n~r;-. 

row strip along East 

River, at the extreme 

west end of the island, 

but they have been 

encountered in a large 

number of wells ip. Brooklyn, in Long Island City, and at s.everal points eastward to Woodhaven and northeastward to M~nhasset Neck. From these occurr~mces it is possible to contour 

the rock surface roughly, as shown in Plate XV. The contours show that this surface slopes 

southeastward at an average rate of about 100 feet to the mile for a distance of.5 miles or 

more. .~a~y minor irreg~larities ~!e br<?ught. out J?y wells that are ~lose together, ·but on the 

whole the slope seems to be very even in the western part otf the island. At Greenport, near 

the east end, the slope is considerably less, rock being encountered at a depth of 670 feet at a 

point ii iniles from the outcrops on the mainland. The statements in regard to the well on 

Fishers Ishi,~d are ·conflicting, the depth to rock being given as 15.0 feet, 204 feet, and 281 feet. 1 

CRETACEOUS SYSTEM . 

. The. discoveries of fossils by which the existence 9f Cretaceous deposits was established 

have been described in the review of geologic literat1,1r:e (pp. 4-2;2). . The well records collected 

in connection with the recent work and the discovery pf evid(3nces· for separating the 

Pleistocene from the Cretaceous clays, with which they had of.teii, been included, have made it 

possible to determine the cl;laracter ·and distribution of the Cretac~.ous beds within fairly close 

liJ;Uits.. The well records have already been published in Vea~ch.,.s report. 2 

I Prof. Paper U.S. Geol. Survey No. 44, 1906, pp. 17, 167, 337. ~Idem, pp. 116 et.seq: 
U. S. GEOLOGICAL SURVEY 

LEGEND 

Bedrock above sea level 

Figures give depth in feet 

below sea level, to bedrock, 

or where preceded by + 

depths of wells which did 

not reach rocK. 

0 

PROFESSIONAL PAPER 82 PLATE XV 

Scale 

10 Miles 

MAP SHOWING POSITION OF BEDROCK IN WESTERN LONG ISLAND. 

By A. C. Veatch. 
CRETACEOUS SYSTEM. 67 

CHARACTER OF THE DEPOSITS. 

The Cretaceous deposits of Long Island differ extremely in composition within short distances. One well1nay show several hundred feet of clay and an adjoining well may show an 

equal a1nount of sand. Nevertheless there appears to be a certain general sequence, which is 

shown in the cohunnar section forming figure 55. 

The tenn "basal clays" is applied to those at the base of the Long Islan,d Cretaceous section as it has been disclosed by well borings, or in other words those lying beneath the Lloyd sand. 

Relatively few sections of 'these lower beds are available; but they seem to consist rather unifornlly of dirty white, gray, and blue clays, with a few beds of gray sand and some grayish 

quicksands. Their total thickness probably ranges from 100 to 200 feet. The beds are nowhere exposed at the surface and are encountered in only a few of the wells near the west 

end of the island. 

Veatch 1 has· given the name "Lloyd sand" to the· bed of yellow to 

white q1.1artz gravel and sand with some clayey layers lying next above 

the basal clays. This is the main Cretaceous water bed and is usually 

about 80 or 90 feet thick. It does not outcrop anywhere at the surface 

but is probably not much more than 100 feet below sea level near College 

Point and in parts of Long Island City. . 

Above the Lloyd sand is a group called "red clays" but containing beds of yellow, salmon-colored, red, brown, chocolate-colored, and 

black clays, with a few relatively thin beds of sand, the total thickness 

ranging usually from 100 to 250 feet but in places exceeding 400 feet. 

The clays are found in the wells of the north shore, and are to be seen 

south of Mott Point, on Manhasset Neck, north of Glen Cove, and in the 

beach below high water at Rocky Point, Cold Spring Harbor. 

Above the colored clays is a bed of "white sand" and clay reaching a thickness of at least 100 feet. This is the white arkose sand exposed on the east side of Hempstead 'Harbor, near Sea Cliff, at Lattingtown, at Center Island, and on Lloyd and Eaton necks. 

The white sands are overlain by about 7 5 feet of "yellow clays," interbedded with red and brown layers. These lighter clays crop out along 

the shore of Cold. Spring :Harbor for more than a mile so~th of Lloyd 

Beach .. 

Next above these clays stratigraphically are the dark slate-colored 

clays of Little Neck and their chocolate-colored to black equivalents 

along the Sound 4 miles northeast of Northport. These beds are ex-

~;~ ~S}~· Undifferentiated (600 ft. l 

I) 

Basal clays (150ft.) 

Crystalline rocks 

posed in many clay pits and are seen to be well stratified and to carry, FIGURE 55.-coiumnar section 

in the latter locality, numerous concretions. Several .beds of light- of the Cretaceous formations 

1 1 h hi of Long Island. colored sand are inc uded among the c ays. T e t ckness of this group, 

which is designated "dark clay" in figures 55 and 56, is estimated to be about 75 feet. 

Nothing is seen of the. Cretaceous between the north coast and the Dix Hills, 4 miles south 

of the Little Neck outcrop; where undifferentiated beds of yellow, gray, and whit~ clays of 

probable Cretaceous age were encountered in a cistern. Five· miles farther south, near 

Wyandnnch, there are considerable. exposures; and at Bethpage and Farmingdale, a few miles 

west of Wyandanch, thick beds of clay are exposed in the clay pits. Allowing a dip of 65 feet 

'to the mile, which is that observed at ·Oyster Bay, and allowing for a difference of 100 feet 

between the surface elevations, we find that a stratigraphic interval of nearly 600 feet must inter- · 

vene between LittleNeck and Bethpage. According to Veatch's well records this interval is occupied mainly by yellowish sand, with a clay bed here and there, as at the base of the Dix Hills. 

1 Op. cit., p. 21. 
68 GEOLOGY OF LONG ISLAND. 

A group that may be called "buff clays" includes.the gray, salmon, and buff clays at Bethpage and Farmingdale and the yellow, buff, and dirty-brown shaly clays near. Wyandanch. 

The observed thickness and the distribution of these clays indicate that their- aggregate thickness is, roughly; 100 feet. · 

Above the clays at Wyandanch and Bethpage is seen the "yellow sand." Talus slopes 

of this sand also appear at many points on the hillsides, and it was seen in a roadside section 

below the crest of the ridge west of Melville. A few clayey streaks occur in it, but the section, 

so far as known, ·is sandy throughout a thickness of 150 feet. 

On the crest of the ridge west of Melville, beginning about 41 feet from the top of the hill, 

the following section was recorded by G. N. Knapp and the writer: 

·Section of marly beds near Melville. 

Ft. ln. 

1. Sandy marly clay, greenish gray ................... :. . .. . . . . . . . . . .. .. .. . .. .. . . .. . .. .. .. 6 

2. Ferruginous, partly indurated, marly clay, yellowish brown ............................. ~ 6 

3. Marly clay; greenish marl, with chocolate-colored clay base ........................ ~...... 1 

4. Ferruginous (weathered) micaceous clay marl, ydlowish brown ......... ~ ............ ·...... 6 

5. Clay marl; :fine green sand mixed with chocolate-colored clay and some quartz sand; typical 

Merchantville of New Jersey (bed No.1).............................................. 1 

6. Weathered, somewhat sandy, semi-indurated clay marl, yellowish brown................... 1 

7. Clay marl (same as No.5, above) ............................. · ..... ~.................... 1 

8. Iron plates alternating with marl, clayey sand, and gravel............................... 2 6. 

9. Coarse green marly sand and clay, with abundant green sand; some quartz pebbles one-fourth 

to one-half inch in diameter; resembles arkose; weathered pits in lower half; like top of 

clay marls of New Jersey ............... _............................................. 3 

11 

These beds and some greenish clays observed by Veatch at 156 feet in wells at Quogue 

and 155 feet in wells at Bridgehampton, at about the same stratigraphic horizon, are among 

the few representatives of the marl series that have been found on Long Island. The marty 

deposits of this section were first described by Veatch 1 as arkose, but in his final report 2 were 

referred to the marl series on the basis of the observations of G. N. Knapp and the writer. 

DISTRIBUTION OF CRETACEOUS DEPOSITS. 

SURFACE OUTCROPS. 

Elm Point.-The westernmost important showing of Cretaceous beds on Lon~ Island is 

situated at Elm Point, on the west side of Great Neck, between Manhasset and Little Neck 

bays, in North Hempstead Township. The Cretaceous deposits at t4is place consist of about 

30 feet of dark-gray clay containing a few lignitic fragments, overlain by 15 to 20 feet of 

Pleistocene gravel and till. 

Thomaston.-A small exposure of sand and other mater-ial may be seen in a railway cut 

between Thomaston and the hmid of Manhasset Bay, at the base of Great Neck. 

West side of I-Iempstead Harbor.-The first indications of the Cretaceous in a journey north 

from Roslyn are found a short distance north of the sand spit known as Bar Beach, where white 

or yellowish Cretaceous clays are occas~onally encountered in excavations at the bottoms of 

gravel pits. A little farther no~th white clayey arkose sands and bleached quartz pebbles appear 

amid the Pleistocene talus, and a considerable number of small exposures of the same material 

are seen in places. The sands are cross-bedded, although on a small scale, and contain many 

pinkish streaks .. The Cretaceous also shows up to an elevation of 150 feet along the highway. 

leading from ·Hempstead Ilarbor to Port Washington Harbor, about a mile north of Bar Beach. 

Ina section at the highest point the Cretaceous was found in 1903 to be upturned at a high angle, 

the contact with the Pleistocene being absolutely vertical for the entire depth of the cut (about · 

25 feet). The materials here were mainly white, cream, and pink clays and sands. These belong 

to the ''white sands '' of figure 56. 

1 Veatch, A. C., Notes on the geology of Long Island: Science, new ser., vol. 18, 1903, pp. 213-214. 

2 Veatch, A. C., and others, Underground water resources of Long Island, New York: Prof. Paper U. S. Geol Survey ;No. 44, 1906, pp. 2D-22. 
CRETACEOUS SYSTEM. 69 

Another good exposure is about half a mile south of Mott Point, where 15 feet of yellowish and reddish clay was seen in the bluff in 1905, and beds of cream, salmon, red, and black 

Cretaceous clays from 6 ·inches to several feet in thickness crop out on the beach between high . 

and low tide limits. They are referred to the red-clay bed of figure 56. 

·Glen Oove.-A little north of Glen Cove Landing there is an outcrop of contorted yellow, 

pink, gray, and black plastic clays having crusts of hematitic sand and containing pyrite concretions. They have an entirely different aspect from the gray and yellow sandy clays (Pleistocene) between Weeks and Red Spring points and have yielded plant remains that establish their 

Cretaceous age. The clays are hidden near the landing, but are well exposed a quarter of a mile 

fa1~ther south and continue for many hundred feet. White, cream, yellow, red, purplish-red, 

gray, and black clays occur in strong contortions in which granitic gravels appear to be involved, 

for they clearly underlie the Cretaceous clay in overturned folds at one .point. The beach is 

covered with a shingle of hematitic sandstone plates. The outcrops belong to the ~red-clay bed 

of figure 56 and are overlain by more or less of the succeeding white-sand b.ed. 

[]] ~ ~ ~~w D EJ] 

:\\farlybeds. 'Yellowsands Buff clays Undifferentiated Dark clays Yellow clays White sands. 

Outcrop Shown by. X 

FIGURE 56.-Map showing known distribution of Cretaceous formations on western Long Island. By l\f. L. Fuller. Legend arranged 

in order of age-youngest formation at left, oldest at right. 

Sea Olijj:-The first outcrop seen near Sea Cliff was in a sand pit on the south sid_e of Mosquito Cove, opposite Glen Cove. Here 10 feet of white cross-bedded Cretaceous sand occurs 

unconformably below Mannetto gravel. At short intervals from this point to Sea Cliff there 

are exposures of Cretaceous deposits, mainly glaring white sand and sandy clay. Thick sections 

are to be seen in some of the big sand pits. Southward from Mosquito Cove there are traces of 

white sand and clay in the bluffs for .a distance of half a mile, but no good exposures occur. A 

show of white clay occurs three-fourths of a mile south of Glenwood Landing. The materials 

are l'eferred to the white-sand bed of figure 56. 

Lattingtown.-The exposure of Cretaceous near Lattingtown is in a clay pit, 6 or 7 feet 

deep, situated just south of the highway, .three-quarters of a mile southeast ofthe village, at 

an elevation of 130 feet. The materials are whitish clay locally tinged with pink and salmon. 

Little sand is present. They belong near the transition from the red clay to the white sand of 

the section shown in figure 55. - · 
'70 GEOLOGY OF· LONG ISLAND. 

Mill Neck.-An outcrop in the railroad cut across the neck between Oyster Bay and Mill 

Neck station is mapped by-Woodworth but is not described. Its stratigraphic position appears 

to b~ near the ·top of the white sand bed of figure 56. 

Genter Island.-The best exposure of clays on Center Island was seen at Rocky Point at 

the mouth of Cold Spring Harbor, where in the beach between high and low tide marks is a 

series of yellow and dark-gray to jet-black, very plastic clays, free from grit and similar to those 

near Glen Cove and Mott Point, with which they are correlated. The darker clays seen in 

the bluffs above tide level appear to be Pleistocene. On the ":est side of Center Island, just 

south of the point where it is nearly bisected by· the marsh, an artificial pit showed in 1905 

several feet of white clay streaked with white and pink sand belonging to the white sand of 

figure 56. White sand and grayish clay were also cut by the dredge in digging a basin a quarter 

of a n1ile south of the neck connecting with the main island .. 

Oold Spring Harbor.-There are two outcrops of Cretaceous materials on the west side 

of Cold Spring Harbor, one about half a mile south of Coopers Bluff and the other opposite 

the village of Cold Spring Harbor, half a mile northwest of the sand bar. The former shows 

only a few feet of white clayey sand, possibly talus, ,but the latter shows 10 feet or more of 

white sand and a considerable amount of yellow, white, and salmon-colored clays in the beach 

between high and low water marks. The sand belongs to the white-sand bed of figure 56, and 

the clays to the overlying yellow clays . 

. The best exposure on the east side· of the harbor is in the large abandoned clay pits just 

sou:th of Lloyd Beach, connecting Lloyd and West necks. In the bottoms ·of the pits the 

material seems to .be light to dark ·gray clay, overlain by a considerable thickness of yellow 

anq. red clays. Many local variations· of color _and composition occur. The deposits l;>elong 

to the yellow clay of figure 56. South of the pits red and white sands show in the beach at 

intervals for a. quarter of a mile, and yellow and white sands with scattered traces of clay occur 

for.:the next t~ee-quarters of a mile·. These deposits· are included ·wi~h the Cretaceous on the 

map, _although there is some reason for thinking that they may be reworked material. . 

: The following is a section of the deposits exposed in this vicinity as given by :Merrill 1 in 

1886.: The correlations are by the present writer. · 

Section on Cold Spring Harbor. 

Feet. 

Wisconsin: Till and stratified gravel. ........... ~ ... " ......................................... 10 

Manhasset formation: Quartz graveL . . . . . ... ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 

Cretaceous: 

Red and blue "loam" or sandy clay ...................................... ·. . . . . . . . . . . . . . . 20 

Diatomaceous earth..................................................................... 3 

Yellow and red stratified sand ................. .' ......................................... 20 

~:::ul;;!~t~~~~~-.- : -. · ... · .· ~: :: : : ~ : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : :': : : : : : : : : : ~~ 

Descriptions of the diatoms have been published by Ries. (See p. 78.) 

Lloyd Neck.-The best exposure on Lloyd Neck is in a high bluff on the north side about 

three-quarters of a mile east of Lloyd Point. The following section was exposed in 1903: 

Section on Lloyd Neck. 

Feet. 

Dune sand ........................................................ : ......................... 10 

Brownish loamy till· (Wisconsin) ............... -. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 · 

Gravel and buff sandy clay, merging locally into lenses of till (Manhasset formation, with lenses of 

Montauk till member). ~ ......... · ......................................................... 30 

Bright-r~d clay mixed with overlying gravel (Montauk?) ....... :............................... 2 

White and pinkish clayey cross-bedded sand (Cretaceous) ...................................... · 48 

The sand is smnewhat arkose-like, and much of it is finely cross-bedded. Its character is 

shown in Plate XIV, B (p. 56). It belongs to the white-sand bed, figure 56. 

Another exposure of clay is found in the bluff facing Cold Spring Harbor just north of the 

~orth end ~f Lloyd Beach. Fo;r some dist_ance along the beaclJ. at this point there is here and 

1 M~rrill, F. J. H., On the geology of Long Island: Annals New York Acad. Sci., vol. 3, 1886, p. 350. 
CRETACEOUS SYSTEM. 71 

there an outcrop of yellowish clay, more _or less undulating or folded, dipping in places as n1uch 

as 35°. It is underlain by a bed of gravel, which is mainly quartz but yields a few pebbles of 

decomposed granite, indicating that it is probably to be regarded as Pleistocene. The Cretaceous 

should be only a few feet lower, however, and it may be exposed from time to time as the waves 

cut into the beach or bluff. 

Great Neck, 1-Iuntington.-At the end of Great Neck, northeast of Halesite, there are a number 

of exposures of Cretaceous deposits. Not far from the po~t where the highway reaches the 

beach a light-gray plastic clay, with a tinge of pink, is seen at beach level. A little farther 

along traces of chocolate-colored clays occur, followed in the next half n1ile by indications of 

saln1on-colored and light-gray clay. White and pinkish clays appear at a number of points, 

the southernmost being just south of the little cove around which the road circles. The beds 

appear to belong near the_ top of the yellow clays of figure 56 and were formerly extensively 

worked. 

Little Neck, Huntington.-Cretaceous beds are exposed on both sides of Little Neck for 

half a 1nile south of Little Neck Point. On the west side little but white cross-bedded sands is 

to be seen~ although a dark-gray clay shows through the beach at one point. On the east 

side, however, the Cretaceous is well shown, both in the bluffs and in the big sand and clay 

pits. One pit contains 20 to 25 feet of coarse whit~ Cretaceous sands, the 1naterials being 

stratified on a broad scale instead of cross-bedded, as is usual. Another pit shows 30 to 40 feet 

of finely stratified and perfectly jointed black and gray clay containing large pyrite concretions 

and 1nany leaves and even lignitized tree trunks (Pl. XVII, A, p. 82). White ·clay is said to 

underlie the dark clay but was not exposed in 1905. Twenty feet of gray and olive-colored 

clays were exposed in a bluff a quarter of a mile south of the wharf at the sand pit in 1905 and 

are referred to the dark clays of figure 56. · 

Eaton Neck.-The Cretaceous materials are best exposed on the west shore of Eaton Neck, · 

frmn Winkle Point on the south to a point about half a mile north of the north end of West 

Beach. At Winkle Point the Cretaceous is represented by only a small show of pinkish sand, 

but in a large amphitheater a quarter of a mile farther north, on Price Bend, more than 30 feet 

of pink, yellow, and white sands with ferruginous concretions and hematitic sandstone plates 

are exposed. Half a mile farther north, and not far from the head of Price Bend, 20 feet of 

pink and white sand is exposed in the bluffs. In the high bluff just north of West Beach there 

is about 30 feet of similar material with a few clay streaks. Beginning a quarter of a mile 

north of the bluff, 10 feet of brown and black micaceous clay overlain by yellow sand is seen 

at intervals for half a 1nile. Three feet of white Cretaceous clays show on the east shore of 

Eaton Neck about half a mile southeast of Eaton Neck Light. ·These beds fall mainly in the 

white sands of figure 56. 

Northeast of Northport.-The n1ost easterly exposure of the Cretaceovs on Long_·Island is 

on the Sound shore about 4 1niles northeast of Northport or a n1ile north of Fort Salonga village. 

I-Iere great 1nasses of chocolate-c9lored and dark-gray to black clays have been upturned on 

the beach by landslides, and lighter-brown clays containing nun1erous calcareous· concretions 

were to be seen in a clay pit opened in.1903. There seems to be at least 30 or 40 feet of the 

clays at this point. They are referred to the dark-clay bed of figure 56. · 

Dix Hills.-On the west ba_se of the northern extension of the Dix Hills, 1~ miles south 

of Greenlawn, there is an exposure of yellow quartz gravel free from granite pebbles and underlain, as shown by a cistern, by at least 12 feet of white, gray, and yellowish clay. It is regarded 

as Cretaceous and is referred to the undifferentiated beds of the standard section. 

l~Vyandanch.-Cretaceous exposures occur in some old clay pits in a deep valley in the 

Half Hollow Hills a little northwest of Wyandanch ·cw est Deer Park). In the northernmost 

pit the clays are n1uch disturbed, being in places upturned at an angle of 30°, apparently as the 

result of creep. The lowest. deposits seen are nearly jet-.black lignitiferous clay containing 

large concretions or disseminated crystals of pyrite. Above this there are locally red and white 

variegated clays. A deep, narrow pocket of yellow sand occurs in the surface of the clay, but 

whether as an infolded mass or in a small erosion channel could not be determined. On top is 
72 GEOLOGY OF LONG ISLAND. 

'L 

a bed of structureless sand and pebbles and granitic fragments resembling till. Elsewher~e in 

the pit 10 to 15 feet of stratified yellow gravel was seen above the clay, and in an adjacent pit 

from 10 to 15 feet of brownish-gray shaly clay occurred. There were soine small granitic fragments on the s_urface. A pit 800 feet south of the first exposed 5 feet of yellow gravel with granitic fragments on the surface. Below this was 10 feet of white and buff sand, and at the base 

10 feet of salmon-colored and white clay. The sections in these pits differed greatly, even at 

points only a few feet apart, and no generalized· section can be given. The beds are correlated 

with the buff clays of figure' 56. . 

Farmingdale and Bethpage.-Clay is exposed in the pits of the brickyard just north of 

Farmingdale. At the time of the .writer's visit from 20 to 35. feet of material was ~exposed. 

This comprised an upper layer of structureless gravel resembling till, from 1 to 8 feet thick, 

resting on a very irregular surface of gray, yellow, and pinkish clay having a maximum thickness of 10 feet. Below this layer the clay was darker, ranging from chocolate-colored to dark 

brown or nearly black. About 10 feet of this dark clay was exposed in 1903. The surface clays 

are somewhat disturbed, the structure being accounted for by creep. They belong t'o the buff 

clays of figure 56. 

The conditions at' the Bethpage pit are very similar to those at Farmingdale. 

Melville.~At the top of the ridge n~ar Melville the following section is exposed. 

Section near Melville. 

Feet. 

Yellowish gravel with rotten granitic pebbles._ ... ~ ........ -... _ ...................... _...... 40 

Fine orange-colored sands ("fluffy") .............................................. _......... 6 

Marly sands. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 

Gray, red, and yellow variegated clay with sand layers 6 inches to 2 feet thick................... 13 

Coarse white or yellowish clayey sand ................................................ ·....... 18 

88 

TP,e yellowi~h gravel at the top is referred to the Pleistocene; the orange-colored sands,' 

which resemble the so-called "fluffy" sands of Miocene age near Kirkwood·, N. J., may belong 

to the Tertiary; the remainder is Cretaceous. Details of the marly beds have already been 

given (p. 68). 'The clay series consists of about· a foot of ferruginous platy sandstone at the 

top, followed by 9~ feet of irregularly bedded stiff, fatty, brittle gray clay blotched with red 

and yellow streaks alternating with lamin~ or thin layers of sand, the sand layers being more 

numerous near the base. At the bottom is 2~ feet of orange-colored sand with some clay streaks 

and a few ferruginous plates and layers stained with manganese. The lower sandy member 

is horizontally but irregularly bedded, the bedding lines being darker and somewhat more 

clayey than the rest. These beds ~re''the highest Cretaceous deposits encountered at the surface on the. island and are to be referred to the marl stratum of figure 56. 

CRETACEOUS DEPOSITS PENETRATED BY WELLS. 

Evidence as to the character of the Cretaceous deposits below the surface n1ust be derived 

from well records. Fortunately many deep wells have been sunk on Long Istand and a large 

number of records were collected in connection with the studies of the water supply. Some 

of the more typicd of these records are presented· here. .One· of the striking features brought 

out by them is the large proportion of sand in the deposits, much more being shown than the 

surface outcrops would seem to indicate. The records are quoted from A. C. Veatch, 1 and the 

numbers are those used by him .. The first record, which is that of a well in the northern par~ of 

Brooklyn (Williamsburg)~ near East River·, gives a representative section of the deposits at the 

extreme west imd of the island. 

1 Prof. Paper U.S. Geol. Survey No. 44, 1906, pp. 168-337. 
CR.ETACEOUS SYSTEM, 

66: Record of well at Meeker and Kingsland avenues, Brooklyn. 

Filled ground ............................................... _: ............. · ... . 

Wisconsin: 

Blue clay with bowlders ....................................................... . 

Sand and small bowlders with water ....... : . .................................. . 

Blue clay ............... .- ............... _ ... · ........ : ..... _ .... ___ . __ ... _ ..... _ 

Light-gray clay ............................................................... . 

Cretaceous: 

Feet. 

0-5. 

5-16 

16-32 

32-72 

72-180 

Saud:_fiot water bearing ............ ·............................................ 180-180. 5 

Blue clay ................... _ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180. 5-205 

Light-greenish clay, passing into dark-greenish clay containing small concretionary 

masses ......................................................... -........... . 

Yellow and dark-colored sandy clay ............................................ . 

Pre-Cretaceous: 

Rock, mica schist ............................. -................................ . 

205-215 

215-225 

225-

73 

The deposits thicken rapidly southward and eastward and even the deepest wells are far 

from penetrating the full thickness of the Cretaceous. The following section shows the character of the beds penetrated at Long Beach, 18 miles southeast of Brooklyn. 

873. Record of well of Long Beach Association at Long Beach. 

Recent: 

White beach sand, with waterworn fragments of shells ............................... . 

Dirty-gray sand, with .small quartz pebbles and particles of vegetable matter .......... . 

Tisbury [Manhasset formation]: 

Fine to coarse gray sand, with a few small quartz pebbles (salt water) ........ : ....... . 

Medium gray sand; no gravel. ............................ _ ... __ .............. __ .. _ 

Grayish-yellow saud and small gravel, with a few greensand grains .................... . 

Yellowish-gray sand ................ : .............................................. . 

Orange-yellow sand and gravel, similar to· Rockaway materiaL ...................... . 

Sankaty [Jacob sand and Gardiners clay(?)]: 

Gray sand and gravel, similar to overlying bed in texture, but not iron stained ........ . 

Large quartz gravel and pieces of blue clay containing sand and graveL .............. . 

Jameco: 

Dark, multicolored coarse sand and gravel; considerable percentage of flattened shale 

pebbles; only 50 to 60 per cent of quartz; some biotite; looks as if it might be a sample taken from the Wisconsin moraine in the center of the island ..... _ . _ ... _ ....... . 

Cretaceous: 

Black sand composed of fine gray qu.artz sand with a large percentage of lignite; some 

FeS and S; several large pieces of lignitized wood at 99 feet ........................ . 

Grayish sand with some free sulphur and a few particles of lignite .................... . 

'\'bite saud with occasional patches tinged lemon-yellow, perhaps due to iron stains; a 

few particles of free sulphur ...................................................... . 

Dark-gray silty sand ................................................................ . 

White sand with small pieces of lignit~; note on bottle says "120, petrified. ·wood" ... . 

Very dark colored clay ("blue clay") .............................................. . 

Coarse gray clayey sand, with particles of sulphur ....................... -- .......... . 

Medium dark-gray sand (salt water) ................................................ . 

Very coarse dark -gray sand .................................... · ..................... . 

Olive-green sand and small quartz gravel; some sulphur salt water ................... . 

Very dark lead -colored clay ....................................................... . 

Vi'hite sand, containing at 190 feet a log of lignitized wood ............................ . 

\Vhite gravel and salt water ........................................................ . 

Clay .............. __ .. _ .. _ .. _ ...... _ .. __ ._. ___ . _____ ... _ ....... _ ...... ____ ....... _. 

Fine sand ............. · .......................................... : ................. . 

Solid blue clay;· at 270 feet fresh water, sweet and chalybeate ........................ . 

\Vhite sand and wood ............................................................. . 

Clay ...................... ____ .... __ .......... __ .. __ . ___ ... _._ ......... _ .. __ ... ___ . 

'\'bite sand and wood ............................................................. . 

Blue clay ......... : ................................. ~ .. _ ........................... . 

White sand, wood, and water ....................................................... . 

Blue clay ............................................... · .......................... . 

\Vhite sand containing wood and artesian water ...................................... . 

Feet. 

0-36 

36-40 

40-50 

51-55 

55-65 

65-70 

70-73 

73-76 

76-82 

82-90 

90-99 

99-107 

107-111 

111-119 

119-121 

121-135 

135-143 

143-145 

145-156 

156-158 

158-174 

174-192 

192-196 

196-200 

200-220 

220-270 

270-276 

276-282 

282-297 

297-305 

305-308 

308-317 

317-325 
74 GEOLOGY OF LONG ISLAND. 

Cretaceous-Continued. Feet. 

Blue clay. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 325-340 

"'White sand and mineral water; has considerable C02 , sparkling and effervescent ....... 340-356 

Blue clay... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 356-360 

"'White sand and pure water..... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 364-378 

Blue clay. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 378-380 

White sand. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 380-381 

White clay ......................................................................... 381-383 

Fine sand with artesian water ........... · ............................................. 383-386 

The next section is that of a well on the north side of the island between Hempstead Harbor 

and Oyster Bay, which cuts beds of a stratigraphically lower horizon. · 

4-70. Record of C. 0. Gates's well near Peacock Poirit. 

Pleistocene: Feet. 

Sand and graveL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0-40 

Greenish-gray sandy clay, with a few quartz pebbles .................... :............ 45 

Dark reddish brown sandy clay, with some biotite .... _ ................... _._........ 60-80 

Tra:p.sition: 

Fine gray sand ... _ ........... __ ... _ . _ .. _ ....................... _ ......... _ . _ ..... . 

Cretaceous (undifferentiated): · 

Laminated reddish-brown sandy clay; no biotite ... __ ... _ ......... _ .............. _ ... . 

Very fine pinkish-white micaceous sand ......................... · ..... _ ...... " ....... . 

Light-gray medium micaceous .sand ...... _ ....... _ ................. _ .... __ ......... . 

Dark grayish brown sandy clay ........ _ .......................... _ ..... __ ......... _ 

Pebbles of ferruginous sandstone ............... _ ...... _ .......... __ .... _._ .. _ .. __ . __ 

Laminated red and white clay. In the fragments furnished the laminations show very 

great distortion; whether this is the. natural condition of bed or is the result of the 

method of taking samples is not known. Sample 17 contains a few fragments of a 

lamellibranch, but the sample shows evidence of having been laid out oh the ground 

90 

95 

100 

105-130 

135 

140 

before it was packed in the bottle, and the shell may have been picked up there ...... 145-160 

Brick-red, very plastic clay ............................ _ ............. _ ...... _ ... _ ... 165-190 

Cretaceous (Lloyd sand) : 

Fine reddish sand; the red color seems to be due in a great measure to the red clay from 

the overlying bed ............................ ·_ .................... _._ .. __ ..... _ .. 195-210 

Medium light-yellow sand .. _ ... _ ...... _ ............... : ........ __ ... _ .... _ ......... 215-225 

Fine to coarse light-yellow quartz gravel, with a few fragments of white, chalky-looking 

chert ............................................. _ ......................... _ .... 230-

The following section shows the materials encountered in a well on Eaton Neck only a few 

miles from the point where the Cretaceous surface descends permanently below sea level: 

670. Record of L. A. Bevin's well on Eaton Neck. 

Pleistocene: 

White sand and gravel, with a percentage of erratics ................................ . 

Cretaceous: · 

Medium-coarse white sand .. ____ .. __ .. ____ . __ .. __ .. __ . _. _. __ ... _. __ . _ .. _ ... _ .. _ .. __ 

Sand and small pebbles with a rather pinkish cast .... ___ .. _. __ ..... __ .. _. ___ .. _._ ... . 

Coarse pinkish-white sand .. __ . __ ....... · ....... ___ .... _ .. _ .. __ .. __ .. _ .... ______ .... _ 

Medium white micaceous sand .. _ ...... _ ... _ .. __ .~._. ___ ._ ... _ ... _. __ ... _._ ...... _ .. _ 

Very fine gray micaceous sand .. _ ....... ·_ ......... _ ... __ ......... _ .. __ ... _ . ___ . _ . _ .. _ 

Medium to coarse white sand .. ___ ... _ .. _ : ...... : _ .. ___ .. _ . ___ .· .... _ . _ ... _ ........ _ . 

Small angular quartz pebbles, evidently broken from larger ones._ ..... _. __ .. __ .... _ .. . 

Medium to coarse white sand .......... _ .. __ .. __ .. __ . __ .. _ .. __ .. __ .. __ ..... _ ....... . 

Medium white sand._. ___ ... ___ ......... _ .......... _ ..... _ ... _ ................. __ .. . 

"'White clay (''kaolin'') .... ___ ..... _ .................... _ .... _ .... _ ............. _ .. . 

Small white quartz pebbles ... __ ... : ...... _ ....... __ .. __ .......... _ .. _._ ... __ ._ ... . 

Fine gray micaceous sand. ___ . _ .... _ . _ . __ . ____ ... _ . ___ .. __ ... _ . __ ... _ . __ .. _ .. __ .. __ . 

Medium-coarse white sand ... ____ ... _ .. ___ ..... __ ..... ___ .. __ ... __ ... __ . _ .. ___ . ___ _ 

Fine white micaceous sand. _ . _ .. _ ...... _ ....... _ ...... __ ............. __ ...... _ . _ . __ . 

. Medium yellowish-white sand ........... _ .. _ .... _ ....... : ........... ___ ... ____ .... . 

Fine sand and small quartz pebbles .............. _ .................... ____ .. _ .. _._ .. 

Feet. 

15-30 

40 

50-75 

80 

90-100 

110 

120 

130 

130 

150 

159-160 

165 

250-300 

215-240 

250-300 

310-330 

335-350 
CRETACEOUS SYSTEM. 

The two following sections show the character of the Cretaceous deposits underlying the 

North and South flukes of Long Island: 

$92. Record of test well of Greenport waterworks, Greenport. 

Feet. 

Wisconsin: Yellow gravelly materiaL ........................................... :....... 0-20 

Tisbury [Manhasset formation]: Alternate series of sands and graveL....................... 20-100 

Sankaty [Jacob sand and Gardiners clay(?)]: Brown clay similar to that in Sanford's brickyard ................................................................... ~ . . . . . . . . . 100-150 

Jameco: Fine sands ..................................................................... 150-225 

The well was then completed by Mr. E. K. Hutchinson, the only record kept being a. few 

samples in a test tube preserved by Mr. Fred Klip. These show the following materials: 

Coarse yellow sand and gravel (probably. glacial) ..................... _ ...... _· .. __ ._ ... 225-

Coarse quartz sand ............................................ _ .. __ ........ _ ... _ ... . 

Coarse quartz pebbles (one granite pebble) ............... _ ......... _ ... _ ........... . 

Ferruginous quartz conglomerate .................................................... . 

Cretaceous: 

V\'hite, highly micaceous sand ............................... : ...................... . 

Fine white sand ............ , ................. ~ ................................... . 

~;~~~~;:~d ~~:;~-a~~~ _c_l~:-- _· ~: ~ ._ ._ ._. _- _- ~: : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 

Yellow sand and clay .................................. _ . _ .. _______________ . ____ .. . 

Yellowish-white clay ......................................................... _ ... . 

Salmon-colored clay .......................... _ ... _ .......... ___ . __ .. ____ .. __ . _ .. __ _ 

Fine, rather dark quartz sand ......................... _ ... _ . ____ . _________ .. _____ . _ 

-555 

555-605 

605-612 

612-619 

619-635 

635-640 

640-645 

645-

Fine dark-colored sa.nd ......................... ~..................................... -650 

Coarse quartz sand containing fresh water (Lloyd sand?) ............................. 650-670 

Pre-Cretaceous: 

Schist ............................................................................ 670-690 

897. Record of Sanford & Son's well, Bridgehampton. 

Tisbury [Manhasset formation]?: Gray micaceous clay, with a few small quartz pebbles ..... 

Sankaty [Jacob sand and Gardiners clay(?)]: Medium grayish-white sand and gravel, with 

pieces of greenish clay containing fragments of shells .............................. . 

Jameco: 

Fine to medium orange-yellow sand ................................................ . 

Orange-yellow gravel, apparently identical with that of the old glacial bed on Gardiners 

Island-............. : ........................................................... . 

Very fine yellow silt, with orange graveL ............................................ . 

Cretaceous: 

Fine gray sand, with muscovite and lignite ......................................... . 

Medium yellow sand, with fragments of shells ............................. -- ........ . 

Gray clayey sand, with fragments of shells .......................................... . 

Greenish-gray sandy clay, with fragments of shells .................................. . 

Very fine dark-gray sand, with some coarse white quartz sand ........................ . 

Fine light-gray sand .............................................................. . 

Fine to coarse light-gray sand with partly lignitized wood ........................... . 

Medium white micaceous sand ..................................................... . 

Fine light-gray sand with lignite .................................................. . 

Lignite and large flakes of muscovite .............................................. . 

Medium white micaceous sand ...................................... _,_ ............. . 

White sand, muscovite, a.nd lignitized wood .......................................... . 

Fragments of iron pyrite ........................................................... . 

Fine to medium grayish-yellow sand ............................................... . 

70 

100 

105 

110 

112 

115 

140 

140 

155 

165 

190 

210 

215 

222 

231 

235 

275-287 

287-288 

288-300 

The Cretaceous deposits, although visible at the surface at only a few points, are shown 

by borings to extend under the whole island. In the eastern half of the island the borings are 

too few in number to indicate anything beyond the general depth of the deposits, but in the 

western part there are sufficient, data to represent their position by rough contours, as in Plate 

XVI, which differs from the similar map by Veatch 1 in that the deep valley of the "Sound 

River" shown by him between Roslyn and Whitestone is omitted as not being indicated by the 

1 Prof. Paper U.S. Geol. Survey No. 44, 1906, Pl. III. 
76 GEOLOGY OF LONG ISLAND. 

recor~s and outcrops, the contours near the coast are modified, and the Cretaceous area IS 

extended. 

East of the area covered by the map the Cretaceous_ is. encountered in wells at a number 

of points, as shown in the following table based on the records of Veatch: 1 

Wells encountering Cretaceous deposits east of Setauket, Ronkonkoma, and Sayville. 

No. Locality. Owner. 

771 Mount Misery Point. .......................................... : .............................................................. . 778 Patchogue ........... ____ ....... _ ....... __ . . . . . . . . . . . . . . . . . City commission ................................................. . 781 ..... do ............ _____ ...... ___ ...................... · .......... do ........................................................... . 795 Terryville ....................................................... do ............... _· .................. _·_ ....................... . 801 Port Jefferson ......... ___ ..... _ .. __ ........................ J. L. Darling .................................................... . 811 ..... do .... __ ........ __ ............ ______ ................... Port Jefferson Co ....................... __ ........ __ .............. . 825 \Vardenclyffe ...... ____ ...... : __ . . . . . . . . . . . . . . . . . . . . . . . . . . . N ikola Tesla ..................................................... . 

:g . ~~~fo~:: :::::::::::::::::::::::::::::::::::::::::::::::::: ~~~~c~jl:c~~!~: ::::::::::::::::::::::::::::::::::::::::::::::::.: 860 ..... do ...... __ ........ ____ ........ ·_ ... __ . . . . . . . . . . . . . . . . . . . J. Wen delL ...................................................... . 892 Greenport.................................................. \Vaterworks ..................................................... . 

g~~ ~~g~:~~:fntg~_- .' .': :: : : : : : :: : : :: : : : : : : : : : : : : : : : : : : :: : :: : :: : ~:~~s%:. ~-~~~ -_:: ::: : : : : : ~: : :: ::: : :: ::: : :: ::: : :: :: :: :::: :: : : :: :: : 

STRUCTURE OF THE CRETACEOUS BEDS. 

DIP. 

Depth to Cretaceous. 

Feet. 

110? 

99 

39 

407 

20? 

325 

135? 

150? 

156 

200 

555 

115 

260? 

In nearly every place where Cretaceous deposits are exposed at the surface they are much 

disturbed both by folding and faulting, it being not uncommon to find the beds standing nearly 

vertical. Overturned folds occur at several points. .well records, however, show this to be 

merely a surface condition, the beds at a slight depth having only a gentle and even slope to the 

southeast. · 

From observations in wells on the depth of the Lloyd sand, which is about 200 feet below 

the surface on the north shore, Veatch prepared a contoured structure map of the Cretaceous 

which shows that in the Oyster Bay and Huntington region, on the north shore, the dip averages 

80 feet to the mile. This is between three and four times as great as the dip in New Jersey 

(22 feet) and is double that at Port Jefferson (40 feet). The dip probably decreases somewhat 

rapidly toward the east and south. 

FOLDING AND FAULTING. 

As indicated above, nearly every outcrop of the Cretaceous shows marked evidences of disturbance. In some places, as on the road across Manhasset Neck near Port Washington, the 

beds are vertical and dips of 20° to 30° are very common and may be expected at any locality. 

In general, folding is most conspicuous in the clays, which seem to have bent under the action 

of the forces producing the disturbance, while the sands in many places were crushed to a 

structureless mass. The effect~ of the disturbance are most conspicuous along the steep northward-facing bluffs of the Sound shore, less so on the sides of the north-south harbors, and least 

on the general upland surface, as in the sand pit on Little Neck. The surface disturbance is not 

confined to the north side of the island, but is well shown at West Deer Park (Wyandanch), 

south of the moraine. ' 

The depth of the folding does not appear to be very great and probably there is little evidence 

of disturbance at 50 feet below sea level even on the north coast. .There-are few closed folds like 

those at Marthas Vineyard, where apparently a thickness of at lea~t 500leet is involved, aithough 

small closed folds and contortions are seen here and there, as south of Glen Cove Landing, where 

an overturned fold of Cretaceous clay is recumbent on Pleistocene gravels. ·Generally the disturbance is marked either by a mere surface crumpling or by broad, low arches and shallow 

troughs. In a few places detached masses of Cretaceous clay are-found in the till. Faulting: 

is observed here and there. · · · • · ·-• ; ~·;:_ 

1 Prof. Paper U.S. Geol. Survey No. 44, 1906, pp. 168-337:. 
U S.GEOLOGICAL SURVEY PROFESSIO NAL PAPER 82 PLATE XVI 

73°30' 73°15' 

MAP SHOWING THE ELEVATION OF THE CRETACEO U S SURFACE 0:\l"WESTERNLON G ISLAND,NEWYORK 

~ c OulcTops AreaofCre taceous ofCretaccousrocks rocks above SNl level 

Approximate 

~ contours on upper sui-face of Cretacf'ou~ rocl<s, sh O\\rirtQ,elevaLiOtl above 

m·depth bclow sea level 

By A.C.Vea:lch 

modified by M.L .Fuller 

k~=--~=~'======='-~~~~........l'o:Miles 

Points at whid1 

r.:t3ol 

~ 

UwCrelaecous was encoutllered.wilh elevation in l'ect above or depth below sealev-el 

1913 L E GE ND 

r-:;601 

Points at w

~ 

hich t.he C,·etaccous was noL encoun tcred;"'•ith elevation of boltom.o[we\1 in. feet above o!'depth below sea level 

Crct.aceousiOssil ~ 

shells,in place Cretaceous 

~ fossil ahe1ls,not in place 

GJ Cretaceous fOssil leaves. in placC' 

G CreLaceous fossil leaves, not in place 
CRETACEOUS SYSTEM. 77 

FORM OF THE CRETACEOUS SURFACE. 

The general form of the top of the Cretaceous deposits has been indicated in the discussion 

of the distribution of the deposits and is represented in Plate XVI. As shown by the map, the 

Cretaceous surface has a .fairly close agreement \vith the present surface over much of the western 

part of the island, rising well above sea level in each of the necks and reaching almost to the highest points of the island in the Mannetto (West), I-Ialf I-Iollo''-'"' and Dix hills. Long Island Sound 

is a broad, partly filled Cretaceous valley. In fact, the Cretaceous depressions in general coincide \vith the Pleistocene- valleys and the Cretaceous ridges with the high Pleistocene ridges, 

although it is known that there are many niinor irregularities due to Cretaceous folds which 

have no surface counterpart and. it is probable that· there are many minor buried valleys not 

indicated on the surface. If the drift should be removed from the. western half of the island, 

the remaining land mass, though smaller, would differ only moderately from the present in 

form. 

AGE OF THE CRETACEOUS DEPOSITS. 

STRATIGRAPHIC EVIDENCE. 

The resemblance of the clays of Long Island to the similar beds of New Jersey led 

Mather as early as 1843 to correlate them with the Raritan formation of that State, a correlation 

which later work by Newberry, Hollick, and White tended to confirm. The stratigraphic evidence 

disclosed by well records and surface observations in connection with the present work confirms 

the conclusion of Ward that the flora of -the deposits of Long Island is younger than that of 

the clays of Amboy, N. J., a local phase of the Raritan formation, and the beds are therefore 

stratigraphically higher. 

A means of direct stratigraphic correlation is afforded by the Lloyd sand, which is found in 

the wells of both the north and south shores of Long Island and in New Jersey and is regarded 

by A. C. Veatch as "a horizon in the Raritan about 200 feet below the base of the Matawan." 

This would indicate that the outcrops at Glen Cove and Sea Cliff, including the red clays and 

white sands of the columnar section (fig. 55, p. 67), are uppermost Raritan, wliile the overlying 

yellow and clark clays.are the supposed equivalents of the Magothy and :Matawan formations of 

New Jersey. The leaf remains in the dark clays on LittleNeck do not necessarily indicate the 

deposits to be Raritan, as collections made by E. W. Berry in the Matawan show essentially the 

same flora. Above the deposits which are believed to represent the Magothy and Matawan 

tpere is a great thickness of alternating sands and clays, with some lignite (undifferentiated bed 

of fig. 56), and, although correlation with specific formations is impossible, they show a general 

resen1blance, especially as regards their sandy character, to the Matawan group (including the 

Englishtown and Wenonah sands), the Monmouth group (including the :Mount Laurel and 

Redbank sands), and the Rancocas group (including the Vincentown sand) of New Jersey. 

Well borings are sufficiently numerous to make it perfectly clear, however, that there are on 

Long Island no thick greensand beds like those in New Jersey, their stratigraphic position 

being occupied by the sands mentioned. The observations of Newberry, Hollick, White, and 

Berry on the flora and the discovery of a probable Upper Cretaceous fauna in the Lloyd sand· 

semn to indicate that the Raritan, with which the lower. beds of the Cretaceous of the island 

are correlated, is basal Upper Cretaceous. 

FOSSILS. 

A large number of Cretaceous fossils have been found on Long Island and are described in 

papers by Newberry, Hollick, Ries, and others, but, except those of the outcr.ops at Glen Cove, 

Cold Spring Harbor, and LittleNeck and those in the wells at Roslyn and Lloyd Point, the fossils 

have been obtained from materials transported by glacial ice rather than from undisturbed Cretaceous beds. The following list of fossils fron1 the island includes species other than those first 

cles9ribed from the island or those of questionable identification. The list of plants is furnished 

by Arthur I-Iollick and that of marine forms by Mr. I-Iollick and A. C. Veatch. 
78 

Locality. 

Brooklyn, Clark St .................... . Brooklyn, De Kalb A vc ............... . East New York ....................... . Do ................................. . Do ................................ . Do ...................... · ........... . Williamsburg .......................... . Elm Point ............................. . Do ................................ . Do ................................ . Do ................................ . Manhasset Neck ....................... . 

~eO:gliff·_-_-_-_ ·_ ·_-_-_ ·. ·. ·_ ·_-_-_-_ ·_ ·_ ·. -_-_-_ ·_·_ ·_ ·. ·_ ·.: : :: : 

Do ................................ . Do ................................ . Do ................................ . Glen Cove ............................. . Do ................................ . Do ........... : .................... . Do ................................ . Do ................................ . Do ................................ . Do ................................ . Do ....................... · ......... . Do ................................ . Do ................................ . Do ................................ . Do ................................ . Do ................................ . Do ................................ . Do ................................ . Do ................................ . Do ................................ . Do ................................ . Dosoris Island ......................... . 

Oak Neck Point ........... : ........... . Center Island .......................... . Do ................................ . Do ................................ . Cold Spring Harbor ................... . 

Llo~ ~e-~~ ~::::::::::::::::::::::::::: Do ................................ . , Do ................................ . Eaton Neck ........................... . Little Neck ............................ . Do ................................ . Do ................................ . Do ................................ . Do .... : ........................... . Montauk Point ........................ . Do ................................ . Do ................................ . Do ................................ . Do ................................ . Do ................................ . Do .............................. · .. . 

GEOLOGY OF LONG ISLAND~ 

Cretaceous fossils from Long Island. 

Name. Source. 

E xogyra sp ( ?) ....................................................... · Drift. 

Juglans crassipes Heer............................................... Do. 

Gryphrea vesicularis................................................. Do. 

Ostrea larva ...................................... , . . . . . . . . . . . . . . . . . . . Do. 

Cucullrea sp ( ?). • . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Do. 

5lt~!~~~~~~fH·:·•::•:::::::::::::::.:::::••::•:: II: 

Platanus newberryana Heer.......................................... Do. 

Nelumbo kempii Hollick............................................. Cretac.eous clays. Terebratula filosa.................................................... Cretaceous in well. 

Salix proterefolia flexuosa Lesq uereux. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Cretaceous clays ( ?). 

Proteoides daphnogenoides Heer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Do. 

Andromeda parlatorii Heer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Do. 

Magnolia tenuifolia Lcs:luereux (?).................................. Do. 

!~~f~::!~~l:~:f~~l~~~~:.: _::::::::::::::::::::::::::::::::::::: cretEc~:ous clay. 

Premnophyllum trigonum Velenovsky .............................. Do. 

Sassafras basta tum Newberry (?).................................... Do. 

Laurus plutonia Heer ............................. :.................. Do. 

Sassafras acutilobum Lesquereux.................................... Do. 

Podozamites angustifolius (Eichwald) Schimper . . . . . . . . . . . . . . . . . . . . . Do. 

Diospyros primreva Heer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Do. 

Dammara microlepis Heer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Do. 

Myrto£hyllum (Eucalyptus) geinitzi Heer........................... Do. 

~~~~g~ fe~~~frlo~r~~~~~~~:::::::::::::::::::::::::::::::::::::: E~: 

~:ru~n: ~~~~W:dr:ti~~r-:::: :: ::: : :: : :: : :: ::: : :: :: : :: : :: : ::: :: : : : : : : : E~: Poacites sp ........................... , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Do. 

Liriodendropsis simplex Newberry................................... Do. 

Sequoia sp........................................................... Do. 

Linodendropsis simplex Newberry................................... Drift .. 

~~!~g~~a_~n1~RF~d'~ N'e~blrry: : :: ::: : :: : : : ::: :: :: :: : ·::: :: : ::: : ::: :: : E~: Frenelopsis hoheneggeri (Ettingshausen) Schenk(?)................. Do. 

Quercus morrisoniana Lesquereux................................... Do. 

Magnolia capellinii Heer (Glen Cove)... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Do. 

~i~~:~£t~~~1t~it~:~~:::::::::::::::::::::::::::::::::::::::::: ~r~~tc:.ous clays. 

Tricalycites papyraceus Newberry. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Do. 

Clausa amencana .................................................... Cretaceous in well. 

Colutea primordialis Heer............................................ Drift. 

Brachyphyllum macrocarpum Newberry............................ Cretaceous clays. Laurus augusta Heer................................................. · Do. 

Celastrus arctica Heer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Do. 

Paliurus integrifolius Hollick......................................... Do. 

Eucalyptus(?) angustifolia Newberry................................ Do. 

Tricalycites papyraceus Newberry................................... Do. 

Gryphreas,p (?)............. ............ ................... ......... Do. 

Turritella hppincotti Whitfield....................................... Do. 

Dosinia. gabbi Whitfield.............................................. Do. 

Veniella inflata (Conrad)............................................. Do. 

lEnona eufaulensis Conrad. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . Do. 

Corbula sp (?) ................... .'................................... Do. 

In addition to the macroscopic fossils in the above table, a large number of diatoms, etc., 

have been enumerated by Ries 1 (identified by C. H. Kain and others). These were all obtained 

at localities where Cretaceous deposits are known to occur, but none of the Pleistocene clays 

have so far afforded them. The species are all fresh-water forms. 

Cretaceous diatoms. 

Wyandanch ............ : ...................................... Melosira granulata [Ehr.] Ralfs. 

Northport ........................... · ......................... Melosira granulata [Ehr.] Ralfs. 

Diatoma hyemale K. B. 

Cocconema parvum W. Smith. 

Center Island ................................................. Stephanodiscus niagarre Ehr. 

Glen Cove .................................................... Melosira granulata [Ehr.] Ralfs. 

Stephanodiscus niagarre Ehr. 

Diatoma hyemale. 

Melosira granulata (Ehr.] Ralfs. 

1 Ries, Heinrich, Microscopic organisms in the clays of New York State: Trans. New York Acad. Sci., vol. 13, 1894, pp. 165-169. 
TERTIARY ( ~) SYSTEM. 

Cold Spring Harbor (diatom bed) ................................ Stephanodiscus niagarre Ehr. 

TERTIARY(?) SYSTEM. 

DISTRIBUTION. 

Epithemia turgida [Ehr.] Kutz. 

Encyonema ventricosum Kuti. 

Cymbella delicatula Kutz. 

Cymbella cuspidata Kutz. 

Navicula viridis Kutz. 

Navicula cocconeiformis Greg. 

Navicula major Kutz. 

Navicula varians Greg. 

Navicula lata Breb. 

Eunotia monodon Ehr. 

Gomphonema capitatum Ehr. 

Stauroneis phcenecenteron Ehr. 

Fragilaria construans Grun. 

Synedra affinis K. B. 

Campyloneis grevillei var. regalis. 

Triceratium trifoliatium. 

Long Island has never yielded any fossils of Tertiary age, the diatoms from Roekaway and 

elsewhere described by A .. :M. Edwards 1 being from deposits that are clearly interglacial or 

postglacial. Lithology and stratigraphy must therefore serve as guides in determining the 

presence or absence of Tertiary deposits. · 

Eocene and :Miocene deposits are definitely recognized in New Jersey and the Lafayette 

formation is dou bt~ess present, although it has· not been clearly differentiated. The Eocene 

(SharkRiver or upper marl) is a blue marl about 11 feet thick resting with a slightly discordant 

dip on the beveled edges of the Cretaceous. It occurs in eastern New Jersey as a narrow strip 

outcropping between the l\1iocene and Cretaceous beds and is intersected by the ocean at Deal 

Beach. Though covered farther south by later deposits, it seems to be continuous across the 

State in that direction. Its probable extension toward the northeast is suggested by fossils 

found in the drift on Cape Cod. The Miocene is well developed across New Jersey, where it 

includes the IGrkwoocl formation and the Cohansey sand, and .it occurs .on l\1arthas Vineyard 

and possibly at Marshfield, near Plymouth, Mass. It appears probable that originally both 

the Eocene and the l\1iocene extended· across the Long Island area to the New England coast 

and that their presence or absence to-clay depends solely on the amount of erosion to which the 

region has been subjected. 

EOCENE (?) SERIES. 

On Long Island a few feet of marl has been found at Melville and in the wells at Quogue 

and Bridgehampton (p. 68). The str~tigraphic position of the bed at Melville, which is the 

only surface exposure, is very close to that at which the Eocene would occur if the Cretaceous 

maintains the same thickness as in New Jersey,and its strike is as indicated on Plate II (in pocket). 

The composition and the presence of the stony layers (see section, p. 68) agree closely with the 

eharacter of the Eocene inN ew Jersey, as described by Cook,Z who says" it is a mixture of greensand and light-colored earth; the upper 2 feet are quite hard and stony." On the other hand, 

it would be somewhat strange that one particular bed of the Eocene should be present where 

the great mass of Cretaceous greensands are unrepresented. Thus, although it is possible that 

the 1narls at Melville may be Eocene, it"is at least equally probable that they are Cretaceous, 

and they have been so correlated in the present report. 

1 Am. Jour. Sci., 3d scr., vol. 50, 1895, p. 270; Am. Naturalist, vol. 30, 1896, pp. 21~216. 

2 Cook, G. H., Geology of New Jersey, 1868, p. 275. 
80 GEOLOGY OF· LONG ISLAND. 

MIOCENE (?) SERIES. 

Resting on the marls just mentioned is a bed of loose yellowish quartz sand about 6 feet 

thick and similar in character to the "fluffy" Miocene sands (Kirkwood and Cohansey formations) of New Jersey. It occurs at almost the exact position where the Miocene would be 

e.xpected and it may represent that series. On the other hand, sands of identically the same 

character were observed in the Dix Hills at a much lower stratigraphic horizon, unless there 

is an unconformity much greater than there is :any reason to suppose, and very similar sands 

were noted in the Cretaceous area at many points. On the map this sand is included with the 

Cretaceous deposits. 

PLIOCENE (?) SERIES. 

LAFAYETTE ( ~) FORMATION. 

At points farther south the Lafayette was deposited as a sheet overlapping on a slightly 

eroded Cretaceous surface. If the structure of the Cretaceous beds is regular in the Long Island 

region· and if the topography is due solely to erosion, the Lafayette would be expected to occur 

at the top of the Mannetto Hills, if at all. The only bed at this point with which it could be 

correlated is the "fluffy" sand of the Melville section, which resembles the Kirkwood and 

Cohansey formations of New Jersey much more closely than it does the Lafayette farther south .. 

The unconformity at the .base of the overlying gravel of this section appears to be many hundred 

feet, and the gravel could not well be correlated with the Lafayette even if it did not carry 

erratic materials. · 

- Overlying the Cretaceous clays at nearly every point, however, are· more or 'less extensive 

deposits of white or yellow sands.. In some places they are conformable to the clays and clearly 

a part of the Cretaceous, but elsewhere their relations are obscure and they may be of subsequent origin. They are not glacial, for they contain no erratic material. Some of them might 

.b(;) Lafayette if the early Pliocene erosion was strong enough to develop a topographic-relief of 

200 to 250 feet, which is the range of elevation of the clays on which the sanc:ls rest. This is 

much greater than the unconformity found farther south. There is, mor~over, no conclusive 

evidence that the sands are a separate formation. Sandy beds are abundant throughout the 

Cretaceous of the island, and the materials may represent Cretaceous sands slightly disturbed 

and crushed by the ice. On the whole it appears that although the Lafayette may occur, no 

definite evidence has yet been obtained of its presence. 

QUATERNARY SYSTEM. 

PLEISTOCENE SERIES. 

MANNETTO GRAVEL. 

NAME. 

The Mannetto gravel was named from the Mannetto Hills (West Hills), on the crest of 

which just west of Melville some of the best exposures of this gravel on the island were found. 

(See section, p. 68.) CHARACTER. 

The Mannetto gravel, as is indicated .in the table on pag~ 21, is the earliest of the Pleistocene 

deposits. It consists of stratified and in places cross-bedded gravels composed mainly of wellrounded pebbles of quartz from half an inch to an inch in diameter mixed with co~se yellowish 

quartz sand, but carrying everywhere· a few deeply weathered granitic pebbles and scattered 

large bowlders of crystalline rock, also deeply weathered or disintegrated. It includes a few thin 

intercalated beds of yellowish clay. The granitic fragments can usually be crushed by the 

fingers or by a slight blow of a hammer, and even the quartz is far more friable than fresh 

fragments. The quartzose· and stained character of the gravels, the deep weathering of the 

pebbles, and the complex flow and plunge structure are the distinguishing feature's of the 

formation. 
r· 

QUATERNARY SYSTEM. 

SOUJ;tC~ OF MATERIAL. 

The great predo.minance of quartz in. the Mannetto gravel is at variance with the composition of the later glacial deposits, in which granites are very abundant. It seems likely that 

this predominance arises from the nature of the formations of the Coastal Plain farther north: 

Highly quartzose Cretaceous ·beds probably extended across what is now Long Island Sqund, 

overlapping the metamorphic rocks of Connecticut, and, being nearest, furnished a large part 

of the materials of the Mannetto gravel, as compared to the relatively small portion furnished 

by the n1ore ren1ote granitic rocks. 

RELATIONS TO. OLDER DEPOSITS. 

Although only a few sections showing the contact between the Mannetto gravel and the 

underlying beds have been discovered, there is no reasonable doubt as to their relations. In 

the roadside section west of Melville already mentioned (p. 68) the Mannetto gravel rests 

upon a thin bed of loose yellowish sand, probably of Cretaceous age, which in turn rests upon 

impure marls. The Cretaceous deposits, however, do not continue to outcrop farther down 

the hill, the surface consisting of horizontally stratified gravels of the Mannetto type. Their 

relation -is brought out in figure 57. · 

The conditions indicated by the figure are substantiated by observations on the· general 

relations of the older deposits in other parts of the island,· especially at Sea Cliff, where an 

unconformity between the Mannetto and the underlying Cretaceous sands was well exposed in 

a large sand pit. . Together with the Melville 

e~posure and the numerous well records, this 

establishes the existence 

of a great erosion unconformity antedating the 

Mannetto deposition and 

representing an interval 

of suffi.eien t length to adFIGURE 57.-Section showing general relations of deposits in the Mannetto Hills region. a, Manhasset 

formation with outwash mantle; b,. Gardiners clay and Jacob sand; c, Jameco gravel; d, Mannetto 

gravel; .e, Cretaceous deposits. The relations of the Jameco and Mannetto beneath the level of the 

Gardiners are hypothetical. 

mit of the complete removal of the Tertiary deposits, if· such were present, and the reduction 

of the Cretaceous over the greater part of the island from a level at least as high as the crest 

of the Mannetto ridge to and below the present level of the sea. ,.. · · 

STRUCTURE. 

The·Mannetto·gravel, §'O far as can be determined, lies horizontal wherever it is ·not disturbed by landslides or by the drag or shove of the ice sheets by which -it was afterward over-

. ridden. This is shown by the horizontal bedding in the Melville_section, in sections in Wheatley 

Hill near Old Westbury, and in the deeper and undisturbed parts of the Little Neck section, and 

by the extensive horizontal surface ·which it forms south of High Hill at the crest of the type 

locality, the Mann~tto HUls. Great care has to be exercised in determining the dip because of 

irregularities of deposition due to the configuration of the unde~lying Cretaceous beds, as at 

Sea Cliff, and to the flow and.plunge or larger cross-bedding features. 

At points along the coast and to .a less extent in the Dix Hills the Mannetto has been more 

or less disturbed and involved with other beds in the folding due to overriding ice. The.flexures 

may be small, as shown .in Plate XXIV, B (p. 162), or they may be many hundred feet across 

:and correspondingly high, as at points on the north coast.· The conditions under which the 

folding was produced are discussed on page .201. 

DISTRmUTION. 

The Mannetto gravel was in part removed by stream and ice erosion in the subsequent 

interglacial and glacial stages and in part covered by thick deposits laid down upon it mainly 

during the latter stage, so that it is now exposed only at a few points in the erosion remnants 

of the Mannetto and other high hills or in bluff sections or artificial excavations on the north 

shore. .. · · 

1629°-14--7 
82 GEOLOGY OF LONG ISLAND. 

OUTCROPS IN THE INTERIOR OF THE ISLAND. 

Melville . ......:_The finest exposure of the Mannetto yet found is that in the southern half 

of the West· or Mannetto Hills, outside of the moraine. In these hills the Mannetto gravel 

appears to form an extensive terrace ranging from about 270 to 330 feet in height. The format~on could be best seen in 1903 at. the side of the road leading from Melville to the crest 

a mile west of that village. There 40 feet of somewhat irregularly stratified but not crossbedded buff to orange-color~d gravel, mainly quartz with a few rotten granite arid ferruginous 

sandstone fragments, was found resting on the pre-Pleistocene deposits. Essentially horizontal 

gravels of the same type, though somewhat less stained, are seen at intervals to the base of the 

. hill, their relations being as shown in figure 57. 

South erid of Mannetto Hills.-Many sections of the Mannetto can be seen about the south 

end of the Mannetto Hills, especially in the vicinity of Bethpage, Plainview, and Farmingdale. 

In this ·region the old Mannetto topography was buried by subsequent· deposits (Manhasset 

formatio:p.) and the whole was then complexly eroded. As a consequence of this superimposed 

topography the finding of the Mannetto can seldom be predictecl from the altitude or form of 

the surface. In general, however, the Mannetto tends to form the ridges and the. Manhasset 

tends to occur in terraces, as northeast of Bethpage. 

Among the points at which the Mannetto gravel was recognized were the small projecting 

ridge east of the road half a inile northwest of Phiinyiew, the sand pit just northeast .. of the 

Bethpage clay pit, ·sections on the east-west road a mile south of Plainview, and the cut made 

by the east-west road through the hill a quarter·of a mile north of Bethpage Junction. At the 

last-named locality a fine unconformity, marked· by 3: zone stained by iron and manganese, 

was seen between the Maniietto and the overlying Manhasset. The steeper slopes of the Mannetto Hills are commonly covered with talus defyipg identification. 

I-Ialf Hollow Hills.-From road sections it seems probable that a large part of the mass of 

the Half Hollow Hills -also is made up of the Mannetto gravel, although no typical outcrops 

were discovered. Yellowish sands, however, such as occur in this formation at many places, 

were seen in several road cut$. The top of these hills appears to consist of later Pleistocene 

material, abounding in large and relatively fresh granitic fragments. 

. Dix Hills.-The conditions in the Dix .Hills are much the same as- in the Half_Hollow Hills, 

although, ·owing to the morainal belt across the southern portion of the Dix Hills, exposures 

of the Mannetto gravel are fewer. North of the moraine, especia,lly in the hills southwest of 

Elwood, several shallow cuts along the roads-show Mannetto beneath later drift deposits. 

Such dn 'exposure is shown in Plate XXIV, B (p-. 162). , :· 

Wheatley Hills.-Between Wheatley village and Old Westbury is a group of hills projecting 

southward from the moraine for 2 miles or more (Pl. VI, D, p. 32). Superficially these hills 

are covered with till of Wisconsin age,. and they 'were classed by J. B. Woodworth 1 and earlier 

'geologists with the moraine. On careful search, however, a number of excavations were found 

a quarter of a mile north of .Westbury Pond and elsewhere, which showed beneath th~ mantle 

of drift typical orange-colored cross:..bedded Mannetto gravel with its usual rotten granites. 

Well boririgs in other parts 9f the hills~seem ·to indicate that these conditions are general. 

Knobs of the north-shore neclcs.-On the plateau surface of Manhasset Neck (Pl. ·IV, p. 30) 

I on the north shore, there are many well-defuied knobs standing 20 to 60 feet above "the general 

surface. No cuts deep enough to expose the material in them beneath the Wisconsin drift 

were discovered, but a study ·of the composition of the till, in which white quartz pebbles predominate, seems to indicate either. a Cretaceous or a Mannetto core, probably the latter, as well 

records do not indicate that the Cretaceous rises to these elevations. 

1 Bull. New York State Mus-. Nat. Hist. No. 48, 1901, map. 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 82 PLATE XVII 

A. STR UCTURE OF CRETACEOUS CLAYS ON LITTLE NECK NEAR NORTHPORT. 

B. LARGE DECOMPOSED ERRATIC BOWLDER IN MANNETTO GRAVEL. 
MAN NETTO GRAVEL. 83 

OUTCROPS ON THE COAST. 

Broken Ground.-Mannetto gravel of the usual quartzose type appears to occur in small 

quantities overlying the Cretaceous clay at Broken Ground, near Northport, and to be involved 

with the clay in the gr<~at landslides. This is the most easterly point at which the formation 

has been recognized. 

Eaton Neck.-The Mannetto is well exposed on Price Bend, about one-eighth of a mile 

north of Winkle Point on Eaton Neck. The following section was measured: 

Section near Winkle Point. 

Feet. 

Wisconsin drift: Buff till with small bowlders................................................... 5 

Mannetto gravel: . 

Yellow mealy sand with a few pebbles ........................................ ~ .... ·........ 15 

'Vhite and yellowish .clay ...................................... ·. . . . . . . . . . . . . . . . . . . . . . . . . . . 1. 

Sand and gravel with weathered erratic bowlders........................................ . . . 20 

Cretaceous: Pink, yellow, and white sand with hematitic sandstone plates and concretions.. . . . . . . 30 

The bowlders, one of which is shown ·in Plate XVII, B, were of acidic orthoclase 

· granite and ranged from 1 to 2 feet or mor~ in diameter. They are completely rotted and fall 

to pieces on pressure with the hand, so that none are seen in the talus, but a careful search 

, reveals a considerable number in the gravels. · 

A little north of the head of Price Bend another good exposure was seen, the Mannetto 

here being overlain by 4 feet of a chocolate-colored clay. The contact is sharp and shows a 

strong unconformity. Mannetto gravel is also to be seen at a number of places·farther north 

along the shore. , 

Little and Great necks, Huntington.-Gravel, probably Mannetto, shows in the talus at a 

considerable number of points on both the east and west sides of Little Neck near its north end 

but was not recognized in the clay and sand pits. On Great N~ck quartz gravels containing 

weathered gr~nite pebbles occur in outcrops and in the talus above the Cretaceous deposits 

at a number of points near the entrance of Northport Bay. 

Lloyd Neck.-Oh the north side of Lloyd Neck the Mannetto was apparently removed 

by the erosive action of the ~1ontauk ice, no indication of it being seen over the· Cretaceous 

outcrops at that place. Back of the south end of the beach southwest of Lloyd Point and at 

the base of the bluff just north of Lloyd Beach, talus slopes, seemingly of Mannetto materials, 

are seen. The section at this point is given to show the character of the clayey phase of the 

for1nation. 

Section north of Lloyd Beach.· 

Feet. 

Montauk till memb~r of Manhasset formation (?): Interstratified yellowish clay and sand with an 

occasional erratic up to 6 inches in diameter ............................................... .- . 2 

Mannetto gravel: 

Dark-gray clay. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1! 

Bright-yellow clay ............................... : ............... ~ . . . . . . . . . . . . . . . . . . . . . . . 1 

Yellow cJay with ferruginous sand and pebble layers ................ ·....................... 2 

Fi~e quartz gravel with iron and manganese stains; weathered granitic pebbles.............. 5 

The beds are folded on east-west axes, the dips ranging from 5° to 30°. 

Ilempstead Ilarbor.-The Mannetto gravel was seen resting on the white Cretaceous sands 

in a number of the sand and gravel pits on the south side of Mosquito Inlet, at Hempstead Harbor. 

In one of these, just across the stream from Glen Cove, an unconformity was exposed in 1905. 

The old Cretaceous surface is marked by a dark band at t~e top of the steeply dipping sand. 

The first· Mannetto layers are whitish, owing to their materials being. derived from the Cretaceous sands immediately underlying them, but in the upper part of the exposure the admixture 

of foreign material gives them a darker color. 

No other good exposure of the :Mannetto was seen on Hempstead Harbor or at any point 

farther west, but the talus slopes afford indications that the bluffs at a number of points south 

of Sea Cliff are composed in part of Mannetto material. Indications of Mannetto material 
84 GEOLOGY OF- LONG iSLAND. 

were noted in the drift on the knobs that rise above the general·crest of Manhasset Neck and 

suggest Mannetto cones. Mannetto gravel was seen above upturned Cretaceous clays in the 

crest of the neck at a point due west of Sea Cliff. 

DEPOSITS PENETRATED BY WELLS. 

Owing to the small percentage of granitic material present in the Mannetto, it is distinguisl1ed 

from ~he Cretaceous quartz gravels in wells only with difficulty. There is, however, good evidence of its presence at a number of places, among which are those mentioned in the following 

paragraphs. The figures in parentheses indicate the number assigned to the well by A. C. 

Veatch in his report on the water resources of the island/ in which detailed records may be 

found. -

The most westerly point at which probable Mannetto m~terial was found was in a test 

well at Fresh Meadow pumping station, south of Flushing (No. 231), where 7 feet of coarse 

orange-colored sand and quartz gravel with a small amount ofwhite chert was found 50 feet 

below the surface. A 20-foot bed of medium-grained reddish-yellow sand with.·some crystalli~1e 

pebbles found at 125 feet in the well of W. K. Vanderbilt, jr., near Lake Success (No. 317), is 

probably in part Mannetto. -A 12-foot bed of hard coarse gravel at 62 feet in the R. L. Cottnett 

well, near Old Westbury (No. 426), is also referred to this formation.". The J. F. D. Lanier well, 

in the same region (No. 427), penetrated 10 feet of Mannetto at the surface. Material that is 

probably Manrietto o~c~s within 30 feet of the suiface in the H. B. Duryea well, near Old 

Westbury (No."430), and at 90 and 106 feet in the E. D. Morgan wells (No. 431), in the Wheatley 

Hills, which probably penetrate a buried valley; · · 

·in the S. Mortimer well, also in the Wheatley Hills (No. 434), the Mannetto appears to 

·extend from a point near the ·surface to a depth of 150-feet~ . Other wells in this region contain 

probable ·Mannetto material as "follows: Yellow ·quartz sand- ~nd gravel at 23 to 56. feet:in ·the 

W. P. Thompson well, near Old~ Westbury (No. 511);. yellow gravel in the first 70 feet"·of'the 

J. H. Harriman well, in the Wheatley Hills; and fine· sand to medium-sized yellowish· quartz 

gravel at 51 to 81 feet in the Jules Kunz well, near Jericho·. In Mrs: I. Vowman's well, near 

Roslyn (No~ 436), the formation is p-robably present as a coar~e reddish gravel-at 90 to 115 feet. 

The orange-colored sand found at 73 to 92 feet in the ·L. C. W~er well (No: 481), at 73· to 

126 feet in the E. Latting well (No. 483), and at 83. to 108 feet in theW. D. Guthrie well (No. 

484), all near Lattingtown, may be Mannet"to, although orange-colored Cretaceo"\].s gravels also 

occur in that vicinity. 

In the Mannetto Hills, according to Veatch, the following beds of the Mannetto gravel 

were penetrated by the well of H. L. Stimpson. The ·correlations, which are Veatch's, appear 

to be based on the occurrence of decayed cherts, which are locally present in the Mannetto but 

are rare in the Cretaceous. · 

586. Samples from H. L. Sti~pson's 'Well in the West HUls .. 

Wisconsin: Clayey sand and gravel with many compound pehbles .. ~ ~ ....... · .... ~ ......... . 

Mannetto: 

Orange-yellow quartz pebbles, with a very fe~ fragm~nts of compound rocks, the latter· 

probably derived from the overlying beds ......... ~ .......... · ..................... . 

Orange-yellow quartz pebbles, with considerable sand and yellow clay and many fragments of decayed white chert. .. : .......... ~- ...... ~ .................. : . ........... , . 

.. Whitequartz sand, with inuch fine-grained red ironstone and decayed chert ........... . 

. ci-etace6ti~?: . 

White t~ light-yellow quartz sand and gravel containing fragments of decayed white chert. 

Fine-to coarse reddish-yellow sand .................................................. . 

Fine to coarse white sand ............. _. ............................................. . 

Feet. 

8- 20 

28 

40 

52 

6Q-120 

125 

130 

Fine to coarse yellow sand ................................ ~ . . . . . . . . . . . . . . . . . . . . . . . . . . 135 

Medium yellow silty sand, with many small brown ferruginous nodules and a few pellets 

of clay ............................................................................ 140-145 

Medium to coarse light-yellow san·d, with many fragments of dark-brown ferruginous 

sands~one ~ .......................................... ~ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150-155 

t Prof. Paper U.S. Geol. Survey No. 44, 1906, pp. 168-337. 

• 
• 

• 

JAMECO GRAVEL. 85 

The Mannetto has not been definitely recognized in any of the wells on the eastern half of 

the island. · A,GE. 

No absolute proof of the age of the Mannetto gravel has yet been found, although all evidence seems to point to its post-Tertiary origin,. The unconformity at its base is much greater 

than any of the Tertiary unconformities in adjacent areas in New. Jersey, even the pre-Miocene 

unconformity or the pre-Lafayette unconformity farther south being small compared with it. 

Mor~over, it differs in many ways from the sandy Kirkwoqd, Cohansey, and·)3eacon Hill formatiqns of New Jersey. The Beacon Hill, for instance, carries many pebbles of rotten quartz and 

chert, whereas the quartz pebbles of the Mannetto are relatively fresh. Again, the .B.eacon Hill 

nowhere carries granitic pebbles, but they may be foun<;l in every expo~ure of the Mannetto. 

The pre-Pleistocene formations, so far as o.bs~rved at the surface, eitl,1ei.' <;>n Long. Isla_nd or 

in New Jersey or in the Coastal Plain States farther south,' are, except for sq~ttered·.pebbles .Qf 

very acid~c E!chist approaching quartzite in character, free from crystallin~ ·fragrri.en.ts. Th~ 

only apparent exception i~ the region under discussion is a granite fragment measuring 2 by 3! 

inches reported from the Cretaceous at a depth of 335 feet in the well of E. D.· Morgan, in the 

Wheatley Hills. 1 . Inasmuch as surface outcreps have yielded nothing of the kind, although 

well exposed· at dozens of points, and especially in view of the well-known carelessness of drillers 

and the possibility of the fragment dropping from a higher level in the well, its evidence must be 

regarded as of doubtful value.. The relative abundance of granites in the Mannetto suggests 

the correlation of the formation. with the Pleistocene rather than with older deposits. The 

presence of erratic bowlders as much as 2 feet in diameter i_s 4l~o suggestive of glacial derivation, 

for although it is true that such bowlders can be ·transported. by floating trees or other agencies 

~esides ice, ~he fact that none are found in the hundreds of feet of Cretaceous and Tertiary 

s~rata exposed at the surface on· Long Island and ~n New J·ersey or, with the exception of the 

doubtful fragrp.ent mentioned.above, in the thousand fe~t or· more of such strata penetrated by· 

the drill makes some other method of transportation ~han :flo~ting trees more likely. The coarse 

average tex~ure of the· ;Mannetto comp~re9. .. witli .t4a_t of .the. Cretaceo1Js and Tertiary deposits 

indicates that a considerable. changejn ~he ~gnditio~$ 9f d~posit~on had taken place sinGe the 

latter were laid down. ·The str~c~ut:·~ · qf. the ·M·annetto, ~sp~cially the details of its ~ross~. 

bedding, and the smooth, gently sloping upper .. s.urface of its -rerriiiants in the .Mannetto Hills, 

is identical with that of parts of the· outwash. from·Wisconsin iG~; Q(l~_t,f} Pleis~ocene ti:rpe, and 

suggests a similar o-rigin. The degree of weathering is~lsO: ·sugg~sti.~~,.:th~ ~e.cay-_pf the granita 

pebbles being what would be expected of an· early Pleistoc~ne- 9-eposit ;r.~t:P:er ·than a Tertiary 

formation. · · 

The available evidence as outlil).ed abo_ve s~ems _tq wa.rr~nt ~4~ in~h;tsiq_.q of _the MaiD;l~tto 

in an early giacial stage of the Pleistocene series, although a strictly fluvial origin of the deposits 

is not impossible. If the formation is glacial outwash, it was probably laid down early in 

the Pleistocene epoch, as indicated by its we.athered character and stratigraphic position with 

reference to the associated deposits of the same epoch, most likely representing the pre-Kansan 

invasion .. 

JAMECO GRAVEL. 

NAME. 

The tern1 J ameco gravel, which was used by A~ C. Veatch in his report on the water resources 

of the island, was derived fro.Jll the J ameco pumping station, near Jamaica South, 3 miles south 

of Jamaica, in western Long Island, where the deposit~ were :firSt recognized in the deep wells. 

CHARACTER. 

The Jamecogravel, althoughit has not beendefinitely.recog~zed at the surfaceatanypoint 

on Long Island, has been encountered in a considerable number of wells. ~n its type locality, 

in the area extending from Jamaica Bay northward toward Whitestone,. it occupies a broad 

1 Veatch, A. C., op cit.,"p. 259 . 
86 GEOLOGY OF LONG ISLAND. 

depression in the underlying rocks (either Cretaceous or Mannetto). It is eB;,sily recognized 

in the wells in this locality because of ·its striking dissimilarity to all other Pleistocene 

beds (exc~pt the Montauk till member of the Manhasset formation) and to the Cretaceous 

formations. The difference between the Jameco gravel and the Mannetto gravel is especially 

marked. Although the older beds are prevailingly light-colored and composed principally of 

quartz, the J ameco is generally a very coarse dark-colored gravel containing a predominance 

of granitic pebbles with a few streaks of black or other dark sands or finer silts (wells Nos. 135, 

195-206, 273, 290, and 291 of table, p. 90). The pebbles are well rounded and of different sizes, 

some being nearly as large as cobbles, but toward the .east they become finer, being commonly 

from half an inch to 2 inches in diameter. · . , 

. It should be noted that although on Long Island knowledge of the Jameco is deriv.ed 

mostly from samples obtained from well borings, the gravels beneath the Gardiners clay are 

well exposed at several points farther east, where fQlding has brought the beds to higher levels, 

especially in the Nashaquitsa Cliffs, on Marthas Vineyard; near Highland Light, Truro, on 

Cape Co<;].; and less perfectly between Balls· Point a·nd Clay Head, on Block Island. At most 

of these localities the relatively high granitic content, the absence of notable staining and 

ce.me:ritation, the lack· of marked weathering, and the strictly conformable contact with the 

overlying Gardiners clay effectually preclude any possibility of confusion with the Mannetto. 

The darkest phase of the gravel is 'rather local, being confined mainly to the old Cretaceous 

valley mentioned. In Brooklyn and Willi~msburg, which lie on the .west of the valley, the 

Jameco is usually reported as consisting ~f yellow or reddish sands and gravels, with a little 

hardpan (ill wells. Nos. 5, 23, 37, 38, 62, and 65). On the shores of Long Island Sound the 

: materiitl, as shown by the north coast. wells (Nos. 351, 469, 527, 529, 530, 532, 539, 543, 548', 

549, 613, 633, and 652), is almost invariably a light-colored sand or gravel, although black 

sand (No. 545), brownish sands and gravel (Nos. 628; 629), and coarse granitic gravel (No. 654) 

are .reported in a few records. Along the east side of the buried valley on the south side of the 

isl~nd, as at_ Valley Stream (No. 287), a sandy phase of the Jameco is developed locally, but 

the formation seems to be generally absent east of Rockaway Ridge, although a bed of dark 

clay and sand, probably the Jameco, is found beneath Muncie Island (No. 671). Near the 

east end of Long Island a yellow or white sand or gravel correlated with the same formation is 

found beneath supposed Gardiners clay (Nos. 897,. 901). · 

Where lithologic characteristics are not determinative, the forn1ation is recognized by its 

position below the fossiliferous Gardiners clay. 

·The following sections show the character of the Jameco gravel at ·a number of points. 

The. numbers refer to !ecords in Veatch's report, but the correlations are those of the writer. 

The first is a record of a well west of the Cretaceous valley. 

88. Record of 'Well at Bartlett Street and Flushing Avenue, Brooklyn. 

Recent: 

Filled ground .................................. : ....................... _ ......... _ .. 

Black marsh mud ................................................................. _ 

Blue clay .......................................................... _ .. _ ........ __ .. 

Hempstead gravel member of Manhasset formation: 

Light yellowish-brown sandy clay at. .............................................. . 

Bluish-gray, rather pure clay at ...................... · .............................. . 

Montauk till member of Manhasset formation: 

Highly erratic glacial graveL ....................................................... . 

Medium erratic sand .................. ~ .................... , ....................... . 

Erratic gravel mixed with blue clay ............................................... . 

Herod gravel member of Manhasset formation: Coarse glacial sand· ...... : ................ . 

Jacob sand and Gardiners clay: . 

Feet. 

0- 8 

8- 9 

9- 15 

19 

26 

31- 36 

36- 62 

62- 73 

73- 81 

Impure bluish-gray sandy clay...................................................... 87- 93 

Yellowish-gray sand mixed with clay................................................ 93-108 

Clean light~b1·own medium erratic sand ....................... : ...................... 108-122 

Bluish-gray sandy clay ............................................................ 122-124 

Medium yellowish-brown clayey sand.~ ............................................ 124-127 

• 
• 

• 

J AMECO GRAVEL. 

J ameco gravel: Feet. 

Coarse yellowish-brown clayey sand ... r ••••••••••••••••••• · ••••.•••••••••••••••••••• 127-134 

Very coarse dark-yellow clayey sand ................................................ 134-145 

Very coarse reddish-yellow errati.c sand ............................................. 145-174 

Coarse, highly erratic sand .......................................................... 174-175 

The following well section is typical of the region of the Cretaceous valley: 

204-. Record of Brooklyn test well No.3, Brooklyn Aqueduct and New York Avenue. 

Feet~ 

Wisconsin: Reddish-yellow silty sand and gravel........................................ 0- 9 

Manhasset formation: 

'Fine to coarse reddish-yellow sand with granitic pebbles in lower portion. . . . . . . . . . . . . 9- 45 

Fine light-yellow sand.............................................................. 45- 86 

Gardiners clay: 

Lead -colored clay ............... ·. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86-139 

Fine dark-gray silty sand .......................................................... =- 139-158 

Medium dark-gray silty sand ....... ·.· .. ~ ............................................ 158-160 

Gray clay... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160-201 

Jameco gravel: Fine to coarse dark granitic·silty sand ................................... 201-277 

The next reco:rd shows the characteristics of the deposits in the wells of the north shore. 

Recent: 

652. Record of well of Huntington Light & Power Co. near Halesite. 1 

Filled ground ..................................................................... . 

s,vamp deposit ................ ' .................................................. . 

Manhasset formation; Dark sand and gravel. ............................................ . 

Gardiners clay: Blue clay .......... = .................................................. . 

Jameco (?)gravel: Light-yellowish gravel. .............................................. . 

On the south shore east of the Cretaceous valley the succession is as follows: · 

187. R~c.ord of James Caffery's well near Far Rockaway. 1 

Manhasset formation: Water~bearing strata, almost clear gravel. .......................... . 

Gardiners clay ............. , ............................................... · ................ . 

Jamec9 gravel: ' .... · ·. · . · 

· Black sand with \v'ater which looked and tasted good ................................ . 

No record; .. : .... ·· ................................................................ . 

Feet. 

0- 6 

6-10 

10-70 

70-71 

71-75 

Feet. 

0-42 

42- 66 

66-88 

88-112 

87 

The character of the J ameco in the eastern part of the island is shown in the record of the 

Bridgehamjjt'Bn well (No. 897) given on page 7 5. 

In a number of wells at the Springfield pumping station wood is reported in the Jameco, 

as well as in the~Gardiners .clay. This is indicated in the abbreviated records in the following 

table, taken from the report of Veatch, 1 with the correlations of the writer. 

Well sections at Springfield pumping station. 

Section. 

Well Sand . No. (Wisconsin 

and Man- has~t). 

l.t-.} · .. ) ~:~ l:; ( ~ . 

Blue clay Water-bearing 

with wood sand and 

and sand gravel; some (Jacob and wood and clay 

Gardiners). . (Gardin~rs and Jameco). 

- :g:.·· t •• .> .. 

Feet. Feet. . Feet. , 15 Q-74 74-182 • 182-207' 3 o-50 5Q-117 117-177 2' o-50 5o-124 124-178' 6 ............ .............. 160-177 7 ............ .............. 160-177 8 ............ .............. . 139-179 9 ............ 76-135 ............... . 10 ............ .............. 132-156 

1 Op. cit., p. 201. 
88 GEOLOGY OF LONG ISLAND. 

East of Long Island the J ameco · occur8 at a number of points. Veatch correlates the 

yellowish sands and the bowlder-bearing deposits beneath certain of the clays on Gardiners 

Island with the Jameco, but for the reasons given on page 90 the writer regards' the presence 

of true J ameco on that island as doubtful. 

The stratification of the J ameco where the beds are exposed at the surface farther east is 

fairly regular, cross-bedding being exceptional. An examination of the material at a number 

of points shows that the pebbles have not undergone any great amount of decomposition, although 

they are distinctly more weathered on the average than are the subsequent deposits. The 

thickness of the beds is ordinarjJy not very great, rarely exceeding 100 feet, and- thicknesses of 

less than 50 feet are not uncommon. 

SOURCE OF MATERIALS. 

At the type locnlity in the buried Jameco ch~nnel the pebbles and even the smaller grains 

of the Jameco gravel are prevailingly granitic in character and therefore must have been derived 

from the crystalline area of the mainland on the north. The generally low percentage of quartz 

indicates that very little material was derived from the Cretaceous, from the later Coastal 

Plain formations, or from the Ma~netto gravel, in all of which -the pebbles are mainly quartz. 

Outside of the buried valley n;1entioned, however, much more quartz is present in the Jameco 

gravel, indicating that it ~ust have received con~iderable contributions from the Cretaceous 

forrriati?ns:or the Mannetto gravel. -_ 

. . . . . ·. . . . . . . . . . . . .. RELATIONS TO OLDER DEPOSITS. 

. . - - . - . ~ . - . . . . . . - . . . Th~: Jame~.o .gra.vel.rests. unconformably. upon the older Mannetto and Cretaceous deposits 

(fig. 57/ p."81) , . .the principal portion-on Long- Island -being laid down in the broad buried valley 

·underlying Jamaica Bay and the region to the north, toward Jameco, Jamaica, and Flushing. 

Whether this old valley was cut wholly in Mannetto gravel or whether the erosion cut through 

the Mannetto into the underlying Cretaceous is not clearly shown by the well records. In 

either case the_ ~l_l~onformity amounts to nearly or quite 600 feet, as th,ere is that much difference between the: altitude. of. the. Mamietto .. plateau. remnants and .. that .. o[ .the bottom of .the 

buried valley occupied by the J ameco gravel in the region mentioned. Taken as a whole it 

seems likely that the· J ameco rests upon or abuts ~gainst both the Cretaceous and Mannetto 

(fig. 57)' although to judge ~rom "the severity "of "the" pre-Jameco erosion,· which seems to have 

almost completely removed the Mannetto, the beds probably more commonly rest upon the 

Cretaceous. In western Long Island the accumulation of the J ameco took place almost 

entirely in the valley described. Farther east the deposits were banked against the north 

side of the Cretaceous and Mannetto land masses, such as those of the Mannetto and Half 

Hollow hill region, and in the extreme eastern part of the island they were spread _out over 

the lower and flatter Cretaceous surface which existed there. 

STRUCTURE. 

The structure of the Janieco gravel of Long Island must, in the absence of known surface 

exposur~s, be iri.ferred from t~e attitude of the overlying beds and from differences in the 

elevation of the buried surface. Such criteria are, of course, of value only where unconformities are absent. Although there is no direct evidence on Long Island that the overlying 

beds are conformable with the Jameco, observations on Block Island, Marthas Vineyard, and 

the Massachusetts coast, where the beds are perfectly conformable, indicate the probability of 

similar conditions on Long Island. If this is assumed as a fact and conclusions are based on 

the elevation of the Jameco surface or on the structure of the overlying Gardiners clay, it 

appear·s that the J ameco beds, although nowhere far from the horizontal, are yet more or 

less warped. In the region between- Ridgmyay, Brooklyn, and Valley Stream several undulations from 50 to 100 feet in elevation are brought ou~ by the borings (fig. 58), and beneath 

Rockaway Ridge occurs a similar fold whose existence as a topographic feature is due to this 

·• 

.. 

• 
... 

• 

• 

JAMECO GRAVEL. 89 

arch in the underlying beds. This and similar "irregularities on the north shore of the island 

are brought out by the depths in the table on page 90. -Although the occurrence of the· Jameco 

at the surface on Gardiners Island appears doubtful, it is probably present locally at no great 

distance below sea level and is doubtless involved in the strong folds which characterize· all tli.e 

older deposits of that island. 

DISTRmUTION. 

POSSIBLE SURFACE EXPOSURES. 

At a number of points on Long Island and in its vicinity beds of sand or gravel underlie 

the clays exposed in the bluffs. Sandy beds are in. places intercalated with clayey strata in 

the Gardiners clay, ·but in the absence · ~ 

of well records it is not possible to de- 8 -::- ~ e · .. :1-. 

termine whether the clay seen is the 3, 3. ::; g 

basal clay of the formation or one of ; :;; :g ~ ~ ! ~ ~~ ~:W ~ ~ i ~ 

the upper niemqers. In the former ~ ~ ~~~~ ~ ~ Lf ~ 

case the sand or gr!1vel -wo~ld be; referred to the J ameco; in the latter case 

it would be referred to the Gardiners. ,. ; 

The exposures may, however, be described at this point. 

Jacob I-lill.-In the bluffs of.Jacob 

Hill, which is situated about 2 miles 

west of Mattituck, several conspicuous 

FIGURE 58.-Section from point near Ridgeway, Brooklyn, to Valley Stream. 1, 

. Wisconsin <lrift; 2, Manhasset formation; 3, Gardiners clay; 4, Jameco gravel; 5, 

Cretaceous beds. 

pinnacles of contorted reddish or chocolate-colored sandy clays were seen just back of tlie beach 

in 1904. The ·base was not well exposed, but the relations seem to be as indicated in figure 

71 (p. 98). The gravel may be Jameco, but it seems more probable that the clay is involved in 

an overturned fold resting on the Herod gravel me~ber of the Manhasset formation. 

Mulford Point.-A short distance west of Mulford Point and about 3 miles west of the 

termination of the North Fluke at Orient Point a complexly folded exposure of Gardiners 

clay was noted. At the time of the writer's visit in 1904 nothing could be seen of the underlying ·beds, but Mather 1 in 1843 gave a section which: seems to indicate that the clays are 

underlain by sands, possibly to be correlated With the J ameco. 

Montauk Point.-At a point about .2! miles west of Montauk Light a considerable thickness of gray to greenish sand and fine gravel with some yellow gravel was exposed in 1904 

· beneath 10 feet of interlaminated sand and chocolatecolored sandy clay, with the relations shown in figure 

59. Most pro_bably the material described belongs to 

the Jacob sand, but it is not impossible that the sandy 

o.__ ____ ;....· _.1oo Feet 

FIGURE 59.-Sectfon 2~ miles southwe~t · ~t I.:lontauk 

:Light. a, Gray to greenish sand with some yellow 

gravel; b, interlaminated ··sand· and ·choeolate~olored 

clay; c, banded till (Montauk member of Manhasset-

. clay belongs to the Gardiners clay, in which case "the 

underlying material would be J ameco. 

llog Neck.-On the west side of Hog Neck, 2 miles 

northwest of Sag Harb.or, is exposed a section -that seems 

to show beneath the Gardiners clay a considerable thickness of str.atifi.ed· gravels which would natura~y be correlated with the Jameco gravel. The beds are strongly folded, however, and are probably 

overturned, so that the gravel may be stratigraphically above. the clays though below them in 

the section. (See figs.· 151 and 152, p. 142.) _ 

formation). · 

Gardiners ·Island.-The stratigraphy of the Pleistocene deposits of Gardiners Island is 

complicated by the severe folding to which all the beds except the Wisconsin have. been subjected, as well as by the somewhat unusual succession. Instead of the Gardiners clay being 

represented by a single stratum, as in many localities both east and west of this island, it occurs 

as a series of interbedded clays and sands; moreover, thin clays of very similar character 

1 Mather, W. ,V., Geology of New York, pt. I, 1843, pl. 4, fig. 5, 
90 GEOLOGY OF LONG ISLAND. 

occur in the Montauk till member of the Manhasset formation. Owing to the incompleteness 

of the exposures· or to the complexity of the folding, it is in many places impossible to determine the horizon of a· particular clay bed, and the identification of the underlying sand beds 

is still more difficult. For thi::; reason the writer has found it impossible to identify positively 

the J ameco on Gardiners Island. Veatch 1 describes and figures a section near the middle of 

the northeast coast (diagram reproduced as fig. 60), in which a bed of gravel contaming bowlders 

of granitic rocks is shown between a red clay and a bed of fin.e gray micaceous sand regarded 

as Cretaceous. To the writer, who examined the same exposure at a later date, it appeared 

that the bowlders referred by Veatch to the J ameco are a superficial deposit (Montauk) 

irregularly massed against an ancient bluff, and that the supposed Cretaceous sand is identical 

with beds intercalated with the Gardiners clay at other points and is to b~ correlated with that 

formation. The small unnumbered infolded bed between Nos. 4 and 5 has the appearance of 

belonging to the Herod gravel member of the Manha_sset, and No. 4 resembles the Jacob sand. 

It would be strange if the Gardiners clay, which usually has a thickness of 30 to 100 feet and 

is represented by a number of alternating sands and clays, should at this 

particular point be represented by a 

w single bed only a few feet thick. The 

Jameco is thought to occupy its normal position below sea level, possibly 

banked against the Cretaceous mass, 

the upper part of which is involved 

in the fold shown in the figure. It is 

FIGURE 60.-Section near the middle of the northeast shore of Gardiners Island. o, 

Black Cretaceous clay; 1, fine gray micaceous sand (Cretaceous); 2, Jameco gravel; 

3, redclay,(Sankaty); 4,silty sand(Sankaty); 5, Wisconsin till and outwash gravel. 

Height of section, 60 feet. Section and nomenclature by A. C. Veatch. 

very doubtful if any J ameco shows 

above sea level on Gardiners Island. The folded bowlder-bearing beds which u:q.derlie certain 

clays elsewhere on the island, and which are correlated with the J ameco by Veatch, belong 

almost wholly to the Montauk till member of the Manhasset formation. 

No beds that could be correlated with the Jameco gravel were noted on either Plum Island 

or Fishers Island, although they doubtless occur below sea level. 

DEPOSITS PENETRATED BY WELLS. 

Long Island.-The distribution of the Janieco gravel shown by the wells of Long Island is 

concisely presented in the following table, which emphasizes, first, the concentration of the 

coarse dark g;ranitic gravel in the old Cretaceous depression north of Jamaica Bay; second, 

the finer, more quartzose, and lighter-colored deposits on either side of the depression and on the 

north shore; third, the general absence of the gravel from the south side of the old Cretaceous 

land mass; and, fourth, its occurrence as a light quartzose gravel in the extreme eastern part 

of the island. · Jameco gravel penetrated in wells of Long Island. 

No.a Locality. Owner or place. 

5 Brooklyn. . . . . . . . . . . . . . Rapid Transit Co .......... . 23 ..... do................ 5th Avenue and 18th Street. 

37 ...•. do................. BartlettStreetand Harrison 

Avenue. 

38 .. > •• do................. Bartlett Street and Flushing Avenue. . • 62 ..... do................. TenEyck Street ........... . 65 ...• :do ...•............. Porter and Maspeth avenues. 130 Barren Island ......... · T. F. White Co ............ . 135 East New York .•...... Dept. Water Supply ....... . 136 Aqueduct .............. Brooklyn waterworks ...... . 137 East New York .••.......... do ..................... . ·141 ..... do ...........•••......... do ..................... . 176 North Beach .......... Bowery Bay Building Asso- . . ciation. 

187 Far Rockaway........ Jas. Caffery ................ . 188, ..... do................. B. L. Carroll ............... . 

Depth of formation. 

Feet. 13~212 

b 55-135 

150-165 

13~176 

100 

190 

130-220 

118-164 

128-191 

141-149 

281-284 

36- 82 

Character of the deposit. 

"Hardpan" with black stones and coarse sand. 

Reddish-brown sand and gravel. Coarse red sand. 

CQarse yellow sand. 

Beach sand. 

Water-bearing gravel. Reddish-hrown sands with cobbles. 

Coarse dark granitic gravel. Dark reddish or yellowish sands and granitic gravels. Coarse dark granitic gravels. Gray silt and granitic f.ebbles. 

Coarse sand and grave . · · 

66-112 Black sand. 

65-190 Fine to coarse sand and gravel. 

a Numbers refer to well records in report on underground water resources of Long Island, New York, by A. C. Veatch and others (Prof. Paper U.S. Geol. Survey No. 44, 1906). · · . bIn part. 

1 Op. cit., p. 35. . 

• 

• 
, 

• 

• 

• 

• 

• 

No. 

191 

195 

197 

199 

200 

201 

202 

203 

204 

205 

206 

212 

213 

239 

241 

243 

261 

273 

287 

290 

291 

292 

351 

469 

527 

529 

530 

532 

539 

543 

545 

548 

549 

613 

628 

629 

633 

652 

·654 

671 

897 

901 

J AMECO GRAVEL. 

Jameco gravel penetrated in 'Wells of Long Island-Continued. 

Locality. Owner or place. 

Far Rockaway ........ Queens County Water Co .. . Aqueduct .............. Shetucket pumping station .. Springfield.. . . . . . . . . . . Springfieldpumping station. Jamana South ......... Oconee pumping station ... . ..... do.. . . . . . . . . . . . . . . . Baisleys pumJ?ing station .. . 

:::: :~~::::::::::::::::: b~~~& ~~:E~~-~~~~i~-~:::: . . . . . do ................. Brooklyn test well No.2 .... . Springfield.. . . . . . . . . . . Brooklyn test well No. 3 ... . ..... do................. Brooklyn test well No.8 .... . ..... do ................. Springfield pumping station. 

Jamaica ......... ; . . . . . Brooklyn test well No. 11 .. . ..... do ................. Pumping stationA Jamaica 

Water Supply ~._;o. 

Whitestone............ Pumping station No.1. .... . ..... do ................. Railroad wells .............. . ..... do ................. ,V. \V. Cole ................ . Lawrence.............. D. D. Lord ................. . Hewlett ............... Queens County pumping 

station. 

Valley Stream.. . . . . . . . Watt Pond pumping station. 

Springfield. . . . . . . . . . . . F~i~~~ ~ tream pumping sta-

..... do................. Brooklin test well No. 12 .. . Rosedale...... . . . . . . . . . Brooklyn test well No. 13 ... . Plandome Mills........ Robt. Seizer ................ . Dosoris Pond .......... D. F. Bush ................ . Oyster Bay... . . . . . . . . . Charles Weeks ..... , ....... . ..... do ................. Van Sise & Co .............. . ..... do ................. D. W. Smith ............... . ..... do................. E. K. Hutchinson .......... . ..... do ................. W.J.andA.S.Hutchinson .. ..... do................. 0. L. ·Jones ...... , ......... . ..... do ................. T. Underhill ............... . . . . . . do ................. Hamilton .................. . ..... do ................. William Trotter ............ . 

~!~t~~~k~ ~~~l~_o_r_.::: ~~~~~/J:~:: ::::::::::::::: ..... do ................. Mrs. M. II. Oats ............ . Lloyd Neck ........... 0. L. Jones ................ . Halesite............... Light & Power Co .......... . Centerport............. R. S. McCrary ............. . Muncie Island ......... E. H. Muncie .............. . Bridgehampton........ Sanford & Son ............. . Sag Harbor ............ J. K. Morris ................ . 

Depth of formation. 

Feet. 100 146-154 

106-109 

185-192 

156-200 

135-161 

142-156 

154--258 

201-277 

212-260 

170-183 

189-200 

104-120 

45- 95 85-120 

70- 96 70-100 

120-155 

118-130 

105-115 

98-138 

70-102 

100-113 

95- 97 90-110 

53- 57 50- 65 50- 83 185-190 135 80-107 

80-130 

70- 90 158-176 

116-149 

93- 97 105-122 

71- 75 175-185 150 105-115 

. 143-145 

Character of the deposit. 

Beach sand. 

Coarse dark granitic gravels and clay. Steel-gray sand with jasper pebbles. 

Coarse dark granitic gravel. 

Black sand and gravel. Dark-brown granitic gravel and sand. 

Dark granitic gravel and sand. 

Dark granitic gravels and sands . Do. 

Do. 

Reddish-yellow granitic gravel and sand . Dark granitic gravel and sand. 

Coarse sand and reddish gravel. 

Glacial sand and gravel. Coarse granitic gravel. 

Medium coarse g~vel. 

Coarse sand, changing to gravel. 

Coarse sand and gravel with granitic pebbles. 

Sand and fine gravel. 

Water-bearing iron formation. 

Dark dirty granitic sands. 

Reddish-yellow silty sand and gravel with granitic pebbles. Coarse sand. · Light-colored granitic gravel. 

Micaceous sand. 

Yellow sand and gravel. Fine yellow sand. 

Sand. . . Yellow sand and gravel. Coarse sand. 

Fine gray and black sand. 

Sand . Gravel. 

Fine sand and gravel. Dark-brown gravel mixed with clay. 

Brown gravelly sand. 

Fine to coarse yellow gravel. 

Light-yellowish gravel. Granitic pebbles size of fist. 

Dark clay and sand. 

Yellow and orange sand and gravel. 

Sharp whit~ sand with biotite. 

91 

Plum, Gull, and Fishers islands.-On Plum Island the Jameco probably embraces the 

material from 2! to 89 feet in the Army ";ell. The Herod gravel member of the Manhasset 

formation, the Jacob sand, an<;l the Gardiners clay were evidently here cut out by the Montauk Ice. 

Record of United States Army well on Plum Island, New York. 

Montauk till member of Manhasset formation: Feet. 

Loam. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 - 2! 

Sand and large bowlders ......... :.................................................. 2t-20 

J ameco gravel: 

Fine sand . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 -31 

Fine sand and gravel ................................................. :. . . . . . . . . . . . 31 -49 

Coarse sand and fine gra ~el. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 -89 

Gull Island is only just awash and nothing but till, which may be either Montauk or Wisconsin,' is exposed. The following record probably begins below the Gardiners clay, which, 

if present, would occur at about sea level. 

Record of United States Army well on Gull Island, New York. 

Jameco grav~l (mainly): 

Loam and sand .................................................................. . 

Coarse sand ....................................................................... . 

Very coarse sand ................................................................. . 

Very coarse sand and gravel ..................................................... ~ .. 

Sand ................................... : ........................................ . 

Fine quicksand ....... _. .... : . ........ ·_ ............................................ . 

Sand and clay .................. : . ........................ : ..................... · .. . 

Gravel and sand .......................... : . .......................... : . .... ~ .... . 

Coarse gravel and sand ................................................. _ ........ __ 

Cretaceous: 

Feet. 

0- 30 

30-40 

40-46 

46- 52 

52- 57 

57- 82 

82- 87 

87- 91 

91- 98 

Fine sand ................................... , ....................... ·............. 98-108 

Light-colored clay ................................................................ 108-112 

. Dark-blue clay, rather oily; when exposed to the air became very hard....... . . . . . . . . . 112-291 
92 GEOLOGY OF LONG ISLAND. 

AGE •. 

The glacial or glaciofluViatile origin- of the Jameco gravel is apparently shown by its 

highly granitic .character, and .if, .as. is .. believe~, ... the Mannetto gravel is of similar origin; the 

J ameco was evidently deposited dqring a second glacial stage separated from the first by a long 

interval of deglaciation. The period of erosion between the two stages is somewhat comparable, so far as the effects on the island are concerned, with the long Pliocene epoch: It was·in all 

probability at least as long as several of the later stages put together. This great length 

suggests that several stages of glaciati<;>n might have intervened, but nowhere on Long Island 

or on the New E11-gland coasts· have evidences of glacial; deposits that might be referred to such 

stages been found, not~ithstanding the numerous Jocalities where the older Pleistocene deposits 

have been brought up by folding and exposed. in cliffs 9r have been penetrated by wells. A 

possible clue. to the age of the Jameco is afforded by 'its place in the glacial sequence of the 

island, which .is closely similar to the well-established succession of the Mississippi Valley. 

This evidence as weil as the weathering of the J ameco materials suggests its possible equivalence 

with the Kansan· stage of the interior of the country. 

GARDINERS CLAY. 

NAME. 

The Gardiners clay derives its name from Gardiners Island, situated· between the North 

a1;1d South flukes at the east end of.- Long Island,·oil which several clay beds with included sands 

are well exposed at a numbe~ of points. It is the ex'act equivalent of the Sankaty beds of 

Veatch 1 but is not the .equivalent of the Sankaty beds of J. B. Woodworth/ with which Veatch 

mistakenly correlated it. The term $ankaty beds was proposed by Woodworth· for a series of 

marine sands and gravels with a few minor. clayey layers, locally carrying a Pleistocene fauna, 

which are involved in-the folding that affected all theN€ny·England islands. The·name is taken 

fromSaukaty Head, Nantucket, where the fossils were first observed. No true clay. was exposed 

at the type locality,· except a fossiliferous bed only a few feet in·thickness, although a series of 

bro~nish clayey sands incorrectly designated clay were exposed to a depth of 20 feet at the 

base of the cliff some 50 years ago.3 The remaining. parts of the bluff were made up mainly 

of sands, gravels, and semi-till. 

Later Veatch, 4 on the ground of similarity of. fauna, applied the same name to the blue, ·gray, 

or red Pleistocene clays of Long and Gardiners islands, which reach in the former island, a~cording 

to the evidence. of wells, a maximum thickness of about 100 feet. . .The. p:r:es.ent writer was 

originally inclined to the use of the term/ but subsequent field work, during which the greater 

part of the shores of Long, Gardiners, Plum, Fishers, and Block islands were traversed and the 

bluff sections of Marthas Vineyard, Nantucket, and Cape Cod were visited; brought out the 

fact that the true clays in each of the localities mentioned are ~tratigraphically below the lowest 

of the deposits atSankaty Head and hence should not be included under the same name. Moreover, the Sankaty beds of Woodworth are separable into two distinct. units, the Jacob sand and 

the Herod gravel member of the Manhasset formation (se~ pp. 106 al).d 121), each of which has 

been traced by the writer from western Long Island to Nantucket. The t:rue clays, to which 

the term Gardiners clay is given, are interglacial deposits, but the Jacob sand and the Herod 

gravel member of the Manhasset formation are of glacial origin. The term .Sanka~y as used 

by Woodworth includes materials of unlike character but of glacial origin; as used by Veatch 

it ~pplies to interglacial deposits. 

1 Op. cit., p. 36. 

2 Glacial brick clays of Rhode Island and southeastern Massachusetts: Seventeenth Ann. Rept. U. S. Geol. Survey, pt. 1, 1896, p. 977. 

a Desor, E., ana Cabot, E. C., On the Tertiary and more recent deposits in the island of Nantucket: Quart. Jour. Geol. Soc. London, vol. 5, 

1849, pp. 340-344. • . 

• Veatch, A. C., The diversity of the glacial period ·on Long Island: Jour. Geology, vol. 11, 1903, pp. iu2-77G. 

~Fuller, M. L., Probable pre-Kansan and Iowan deposits. of Long Island, New York: Am. Geologist, vol. 32, 1903, p. 311. 

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GARDINERS ·CLAY. 93· 

CHARACTER. 

On western Long Island, where the formation reaches its maximum development, the 

Gardiners clay consists of irregular dark-colored beds alternating with layers or lenses· of sand 

and fine gravel and attaining near Brooklyn an aggregate thickness of 150 feet. In this region 

the clays, unlike those in the localities farther mist, grade downward through glauconitic and 

locally fossiliferous sand · 

into the Jameco gravel, ,.....-------------, 

representing· in· fact ,~~~~~!~~~~~~~~~~~ tnl.nsitional deposits. ~ The· clays themselves· 

consist of a very fine 

silt, dark from the contained organic· matter 

and carrying more or 

less ligbitized wood. 

The ~ncluded sandy layers are . con1monly from 

5 to 10 feet thick and 

at some · places have 

yielded fossil remains. 

Some of them are 

thought to represent the 

.200 YDS. SOUTH OF BROWNS POINT, 3J/2 MILES 

WEST OF OYSTER POINT 1 LONG ISLAND, N.Y. 

SECTIONS, EXPOSED BY ENCROACHMENTS OF THE SEA NEAR 

BROWNS POINT 1 PETTYS BIGHT 1 LONG ISLAND, N.Y. 

SECTION EXPOSI?D AFTER THE STORM OF 11TA AND 12TH -QI= OCTOBER, 1.836.. 

200 YDS. SOUTH O.F BROWNS POINT 1 LONG ISLAND, N, Y. 

FIGURE 61.-Sections ncar Browns Point. By W. W. Mather. 

··outwash from the adjacent land and others to be channel or shore-line deposits. The lignite 

.fragments that they yield are rounded as if waterworn. 

Toward the east the clays gradually lose their dark ligniti9 color, bluish tints taking its 

place, but, if well records are to be relied upon, they are still fossiliferous. Near the east end 

'of the island the bluish tint is repl~ced by reds and greens, although black clay is to be seen 

-locally on Gardiners Island. The red color is commonly·of a brownish tinge and appears to be 

·due to the presence of material derived from the Triassic area of Connecticut~ indicating the 

probable existerice of Connecticut River in its present position. In some places a more intense 

· ...._ red, similar to the 

• N 

Gardlners 

10 

ci 

0 

Jameco 

~ ·color of the bright ~· o Mauch Chunk shale 0 

CJetaceous Bed rock 

of eastern l?ennsylvania, is to. be seen . 

The amount .of red 

material often appears to be in excess 

of what is .actually 

present because of 

small quanti ties 

that have been 

washed down and FIGURE 62.-Section fro~ Wards Island to Barnum Island, showing fold at Rockaway Ridge (Hewlett) ;md the 

relations of Gardiners clay, Jameco gravel, Cretaceous deposits, and bedrock. ' Jorm a coating OVer 

other deposits. In 

this region the formation is not a lithologic unit but consists of several alternating beds of clay 

and sand each from 5 to 10 feet or mor.e in thickness. Probably the best illustration of this characteristic is afforded by the section figured by Mather in his report on the first geological district 

of New York. 1 Mather's illustration is reproduced here as figure 61. Similar complexity 

is shown by many Gardiners Island sections. One of the features of this phase of the Gardiners 

clay is the lack of persistence of the individual beds. A.clay bed .10 feet in thickness may, for 

-instance, disappear within a space of a few hundred feet, whereas in other sections, as in most 

of the exposures on the M~ssachusetts coast and islands, the formation is clayey throughout. · 

1 Mather, W. W., Geology of New York, pt. 1, 1843, pl. 4, figs. 4-7 . 
94 GEOLOGY OF LONG ISLAND. 

On Montauk Point the clay maintains a reddish tinge, although the color is nearer to 

chocolate than to the bright red of Gardiners Island, and is more likely to be interlaminated 

with fine sand. In fact, the material is intermediate between the deposits of ·aardiners Island 

and those of Port Washington. On Plum and ·Fishers islands the clay is similar to that at 

Montauk, but on Block Island and Marthas Vineyard and at Truro it is blue-gray to nearly 

black. 

SOURCE OF MATERIAL. 

Many difficulties are encountered in searching for an explanation of the derivation of the 

materials composing the Gardiners clay. The presence of fossils bearing evidence of a moderate 

climate and the occurrence of lignite point to accumulation in an interglacial stage, which, to 

judge from the thickness of the clays, was of long duration. In western Long Island, where they 

. reach a thickness several times as great as near the· east end, they may be conceived to have 

been derived from the erosion of Cretaceous deposits. The Mannetto gravel, which originally 

mantled the Cretaceous, had been almost entirely removed, and the J ameco· gravel was below 

sea level. The streams and the sea were, therefore, free to act on. the Cretaceous clays, and 

. ~oubtless it was through their agency that a considerable part of the material for the Gar~iners 

clay, especially the interbedded sands and gravels, was obtained. Probably not all of the 

material was thus derived, 1;wwever, for farther east on the island there appears to have been little 

or no Cretaceous above sea level. A due to the source of the clay in this part of the island 

may possibly be found in its color, which suggests its derivation from Tr.iassic materials, probably brought into the ocean by Connecticut River, which, as previously pointed out, had apparently ·already taken its present course. The amount of clayey sediment now carried by the New 

England rivers is extremely slight, and the accumulation of 30 to· 150 feet of clay over so wide 

an area would, under the present conditions, require a time interval of great length. It is not 

impossible that the land, although low iri the vicinity of Long Island, may have been somewhat 

elevated farther north, in which case erosion would be facilitated and relatively large amounts 

of silt furnished. Of such an elevation at this time, however, the writer knows of no other 

evidence, unless the cool climate is to be taken as indicating the existence of elevated areas in 

the near vicinity-a not very reasonable !;>upposition. 

After the material was once brought to the sea its distribution would probably not be 

difficult, for the region is one of strong and shifting currents, as attested by the many moving 

shoals off Monomoy and Nantucket. · ~ 

RELATION TO OLDER DEPOSITS. 

The contact between the Gardiners .clay and the top of the J ameco gravel is nowhere well 

exposed on Long Island, but so far as can be determined it is everywhere conformable. The 

line of demarcation, as brought out by well records on Long Island and especially by exposures on Block Island,t~Marthas Vineyard, and Cape Cod (see p. 220) is usually sharp, gravels 

of medium coarseness giving way abruptly to clay entirely free from sand or pebbles, as if 

the supply had been cut off by the sudden retreat of the ice sheet, which had previously fur-

. nished coarse materials in abundance. Sharp contacts such as occur in the New Erigland 

islands are presumably present in eastern Long Island. The clay extends for several feet before 

coarser materials reappear as thin intercalated beds of sand or fine gravel, and no coarse gravels 

were laid down untij. after the deposition of 50 to 200 feet of clay and fine sand forming the 

Gardiners and Jacob formations. The only exception to the abruptness of contact seems to 

be in western Long Island, where there appears to be a transition through glauconitic or fossiliferous sand into the Jameco gravel, as brought out in the well records. 

The great body of the Gardiners clay rests upon the Jameco gravel, but along the borders 

of the J ameco next to the Cretaceous land mass, especially along the edges of the great depression in the vicinity of Jamaica Bay, the clay laps up on the eroded surfaces of the Cretaceous 

and Mannetto (fig. 57) or even upon ~he metamorphic rocks (fig. 62), with sharp erosion and 

overlap unconformities. 

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GARDINERS CLAY. 95 

CHARACTER OF THE UPPER CONTACT. 

The Gardiners clay normally passes by gradual transition into the overlying Jacob sand, 

the clay first becoming slightly more sandy, then -alternating with thin lamin::e or lay'ers of 

sand, and finally giving place to the characteristic clayey sand of the Jacob (fig. 61, p. 93). 

At many points, however: the normal conformable contact with the overlying beds is replaced 

by an u;nconformity resulting from erosion by the ice sheet that subsequently deposited the 

Montauk till member of the Manhasset formation. This powerful sheet not infrequently 

scoured through the Herod gravel member of the Manhasset and the Jacob sand into the 

Gardiners clay, so that the Montauk (fig. 63) or, in its absence, -the still younger Hempstead 

gravel member of the Manhasset may rest upon the clay. The erosion has given rise to differences of ·level of many feet in the surface of the Gardiners clay, according to whether the ice 

removed only a few inches or took a considerable portion of its §..:.___ N 

bed, and the greatest differences may be found within a space ·~·~·>:: .'·>·<:;;·:··~ ·.~:~-~ ~-:···:·.>·:·u·~· • - . . o . . · ... ·•· ·.·.' .• · ...• ·~·. 0. 0 ••. 

of a few y. ards. In many places the deposits were strongly · ~-- ~~·~<~ .. _.~·:;,;. :< 

folded by the ice before the Montauk till member was deposited ~~- q;::.--.........~_.o·/·,/.0 -~ 

over the upturned and eroded beds. 

The physical character of the contact with the Montauk 

till member differs with the nature of the till. Where a large· 

amount of debris was carried by. the ic.e, the clay in many places 

FIGURE 63.-Section near Eastern Plain Point, 

Gardiners Island, showing Montauk till member of Manhasset formation in contact with 

Gardiners clay.· 

gives way rather abruptly to a bowlder-clay till, in which the only suggestion of transition is 

the unusual amount of clay and the strong red tinge imparted to the till by the material picked 

up from the underlying Gardiners clay. At other points, where less material was being carried 

by the basal part of the ice sheet, the· demarcation between the two beds is less sharp, the 

Gardiners ·clay gradually becoming les$ regular in lamination toward the top and finally giving 

wny to a structureless or irregularly laminated clay with a few foreign pebbles, indicating a 

reworking by the ice. This slightly reworked layer is a somewhat characteristic feature of the 

top of the Gardiners clay and is in places very difficult to distinguish from the undisturbed clay, 

especially in eastern Long Island and on the New England islands and Cape Cod. 

STRUCTURE. 

At no point where the Gardiners clay is exposed at the surface is it found in an undistillbed condition. At some places it is warped into broad, low undulations (fig. 193, p. 156) and 

~-

9~--------------~~oreet 

at others it is compressed into sharp overturned folds (:fig. 

64), but it is nowhere horizontal for distances of more than 

a few yards. 'Its striking character and sharp contrast 

with the associated beds makes it an ideal key to the 

structure, and it is, in fact, upon this bed that most of 

the structural observations on the island have been based. 

In general the disturbance is most 1narked on the north 

side of Long Island and on the islands farther east, especially where the land presents a st"eep front to the north, 

FrGuRE 64.-Section near Jacob Hill, showing over- becoming less conspicuous in the interior and on the south 

turned fold of Gardiners clay beneath Jacob sand. 

coast. In the former situations the clays are at many 

points thrown into closely compressed, locally overturned isoclinal folds. In practically all 

these folds the axes have approximately east-west directions. The ~nticlines have steeper 

slopes. to the south than to the north, and the overturning is always toward the south.· 

The folding is weakest at the west end of the island and becomes prog~essively greater 

toward the east, reaching a maximum on Orient Point; Gardiners Island, and Montauk Point. 

On the north coast of the western third of the island the Gardiners clay seems to have occupied 

bn,ylike reentrants in the Cretaceous· coast line and to have been protected both by the projecting 

Cretaceous headlands and by the thick overlying Herod gravel member of the Manhasset for:.. 

mation, which took up the greater part of the disturbance resulting from the overriding ice 
96 GEOLOGY OF LONG ISLAND •. 

sheet. In the Jamaica region the ice seems to have overridden an even surface that presented 

few obstacles to its advance, and the disturbance appears to be limited to a fe~ broad undulations apparently due to warping under the influence of the load of ice. 

· Farther east the Cretaceous land was lower, and the Gardiners clay was deposited as a fringe 

around its borders.- · The absence of protecting headlands of the older formation and the relative 

thinness of the overlying gravels left the Gardiners clay with less protection than at points 

farther west, and as a consequence the folding in it is much more pronounced. The details of 

the folding are brought out below, where the .distribution of the clay is described. 

Besides being eroded and folded by the Montauk ice sheet, the Gardiners clay has been more 

or less affected by a slight but somewhat widespread crustal warping. This warping seems to 

be represented by a slight uplift of the eastern ·part of the isl~nd, as compared with the western 

part, the clays being on the whole perhaps 25 feet nearer the surface at Montauk than at the 

Brooklyn end of the island. It is in part to this cause that their more frequent appearance at 

the surface in the eastern portion of the island is due, although the greater folding in this region 

and the absence of the protecting masses of Cretaceous deposits such as occurred farther west 

are perhaps the most important factors. It may be remarked that the uplift appears to have 

been still greater 'in the New Engl~nd islands and on Cape Cod .. 

· DISTRIBUTION. 

SURFACE EXPOSURES. 

The Gardiners clay has been recognized in ·surface outcrops at many localities on Long Island, 

from Manhasset Neck on the west to Orient and Montauk points on the east. It is also found 

on Robins, ,Plum, Fishers, .and Gardiners islands. . 

Hempstead Harbor.-Although, as indicated by exposures of the Jacob sand, into which the 

Gardiners clay grades, the Gardiners is near the s.urface at Plum Point and vicinity and 

~~~~~'9."'!~~~·::o;e!~~~~ near Port Washington 

FIGURE 65.-Section at Rocky Point, west of Cold Spring Harbor. a, Wisconsin till; b, Hempstead gravel 

member of Manhasset formation; c, Montauk till member of Manhasset; d, Herod gravel m~mber of 

Manhasset; e, Jacob sand;[, Gardiners clay. · 

on Manhasset Bay, the 

most westerly exposures 

are those found on the 

east side of Hempstead 

Harbor. Just south of 

Red Spring Point about 5 feet of ·a gray ~andy clay lying near beaQh level apparently represents 

the top of the Gardiners, and a .little farther south, about halfway between Red Spring Point 

·and Glen Cove Landing, another exposure showed a few feet of greenish clay with scattered 

·quartz pebbles ~rom an eighth to a fourth of an inch in diameter, likewise representing the top 

·of the Gardiners clay. Still farther south, although the Jacob sand was exposed at several 

points, the Gardiners clay was not seen,. even where the Cretaceous is above sea level, being 

covered, if it occurs at all, by talus of gravel from the higher parts of the.bluff. 

Rocky Roint, Gold Spring Harbor.-The next exposure of what appears to be Gardiners clay 

is found at Rocky Poip.t, on the west side of .the entrance to Cold Spring Harbor. A low arch 

at this point brings up about 5 feet of dark-gray clay containing the small scattered quartz 

·pebbles characteristic of the Gardiners clay (fig. 65). The upper part of the clay shows the 

greenish-yellow tints due to weathering characteristic of the Gardiners clay. This clay should 

not be confused with the clay outcropping on the beach below high-tide level, which is referred to 

the Cretaceous (p. 70). Auother ·exposure of the day is reported west of Moses Pomt,. at the 

south end of "the island." · 

Lloyd Neck.-At the foot of the bluff facing Cold Spring Harbor, for a quarter of a mile or 

·more north of the base· of the bar separating Cold Spring from Lloyd Harbor, there were to be 

-seen in 1903 a series of yellowish Pleistocene ~lays which possibly represent the top of the Gardiners clay, although they may belong to the Mannetto. The following is a typical section: 

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GARDINERS CLAY. 97 

Section of clays, etc., on L~oyd N~'ck. 

Feet. 

Yellow clay interstratified with sand and containing cobbles up to 6 inches in diameter........ 2 

Bright-yellow clay........................................................ . . . . . . . . . . . . . . . . . 1 

Yellow clay with ferruginous sand and pebble layers......................................... 1 

Yellow clay with clean quartz sand and pebbles............................................ 1 

li'ine quartz gravel with manganese and_iron stains and an occasic;mal decayed granitic pebble, 

extending to tide level. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 

The outcrops show gentle warping with dips of 5° to 10°. In places there are indications 

of gray clay, probably Cretaceous, below tide level. 

Eaton Neck.-In an amphitheater eroded back into the bluffs facing Huntington Bay, a 

little north of the base of West Beach sand pit, 4 feet of chocolatecolored clay of the Gardiner~ type lies unconformably upon a considerable thickness of Mannetto gravel (fig. 66). The clay dips 

toward the north· and approaches the Cretaceous a little farther 

along the bluffs. · Although resembling the Gardiners clay in 

character, this clay lies at an abnormal height above sea level and 

1nay be a phase of the Montauk till member of the Manhasset 

'formation, such as is found near Montauk Point (p. 144). Half a 

1nile north of this exposure 6 feet of black micaceous clay overlain by 3 feet of brownish clayey sand and 20. feet of yellowish 

sand is exposed in the bluffs. This may be Gardiners clay, but the 

freedom of the overlying sarid fron1 granitic or other northern 

n1aterial and its general similarity to the Cretaceous sands indicate 

that the clay should probably be referred to the Cretaceous. 

f' 

FIGURE 66.-Scwtion north of West Beach, 

Eaton Neck. a, Wisconsin till; b, till 

(Montauk till member of Manhasset formation?); c, Herod gravel member. of 

Manhasset formation and Jacob sand; d, 

Gardiners clay ( ?) ; e, Mannetto gravel 

with erratic bowlders;/, Cretaceous. 

Woodhull Landing.-From Eaton Neck eastward for 20 miles no clays of the Gardiners type 

are exposed at the surface, but at Woodhull Landing, northeast of Miller Place, there was in 

1904 a poor exposure of mottled buff to gray clay containing some sand and small scattered. quartz pebbles. 

The clay appears to have a thickness of 10 to 15 feet 

or more and is traversed by joints with dendritic markings. Its characteristics are Gardiners rather than 

Cretaceous. 

Rocky Point Landing.-Half a mile west of Rocky 

FIGuRE 67.-Section half a mile west of Rocky Point Land- Point Landing the section shown in figure 6 7 was 

ing, northeast of Miller Place. a, Buff sand (Herod gravel · observed in 1903 ~ The material along the fault is a 

member of Manhasset formation); b, light-brown clay free tough brown clay free from sand or pebbles, and as 1. t 

from pebbles(Gardinersclay?); c, sandyclay(Jacob sand). 

, resembles the unquestionable exposures of the. Gardiners clay at other localities, it is referred to that formation. A quarter of a mile farther east 

is another exposure having the relations shown in 

figure 68. The material is a bright salmon-pink, 

finely laminated, very plastic clay with mica partings but without sand or pebbles; it seems to be 

10 feet or more in thic~ess. The sand showing 

beneath the clay is probably thin and underlain by the main body of the Gardiners, as the 

thickness exposed is but a small part of that 

usually characterizing the formation. 

Ilallock Landing.-Between Rocky Point and 

I-Iallock landings the beach is wet and springy, 

FIGURE 68.-Section near Rocky Point Landing northeast of 

Miller Place. a, Bright salmon-colored clays with micaceous 

sand partings (Gardiners clay?); b, white sand; c, buff sands 

and sandy clays (Jacob sand). 

with ·occasional poo]s of fresh water, as if the clay were close beneath. The .Jacob sand 

appears at several points, affording further evidence of the presence of the Gardiners clay at no 

1629°-14-8 
98 GEOLOGY OF LONG ISLAND. 

great distance below the surf~;tce. A little clay, possibly Gardiners, was seen in a nearly vertical 

position (fig. 69) a little west of the landing, but i~s relations are somewhat obscure. 

FIGURE 69.-Section west of Hallock Landing. 

a, Gardiners clay; b, granitic gravels (probabiy Herod gravel member of Manhasset formation). 

Roanoke Point.-:-East of t4e last-named locality no Gardiners clay was seen for 10 .to 12 miles, although the indications 

of the Jacob sand observed at a number of points suggest that 

the clay is close to the so' ............ ·.·Q. ·~o •....• ,., , .• -o •·.·o .. , •u 

surface. The springs and 

pools of freshwater along 

the base of the bluff inside the beach and the 

numerous landslips also 

probably indicate the 

l~'' o~~----------~--~ 

FIGURE 70.-Section a quarter of a mile east of Roanoke 

Landing. a, Gardiners clay (?); b, Herod gravel member of Manhvasset formation (? ). 

presence of clay beneath so' "'-2..• ................ --··"·"·· .o .• .., .. .. 

clay was seen a CJ,Uarter of a mile east of Roanoke Land- . "b o.JI/(t 

the surficial deposits. A ==-=--:.-::-::.;~~ a ~ 

ing, where the section represented in figure 70 was ex- \\\\\~t\~( c 

posed. This clay may be the Gardiners. Half a mile o'--------------~ 

h · fi FIGURE 71.-Section three-quarters of a mile east of Roa~ farther east another section, s own In gure 71, was seen. noke Landing. a, Bluff sand (Herod gravel member 

The clay was here strongly folded and overturned. of Manhasset formation (?); b, clay (Gardiners?); c, 

Jacob HiZZ.-The first really good exposure of the Jacob sand<?). -

Gardiners clay is at Jacob Hill, 2 miles northeast of Northville, where several pinnacles of 

contorted reddish or chocolate-colorerl sandy clays stand out prominently just back of the 

beach (fig. 72). The clay seems to be involved in an overturned fold. 

Brown Hills.__:_ No more exposures of undoubted Gardiners clay occur on the.north shore for 

· another 25 miles, the clays at .the brickyards at Conkling Point, 

southwest of .Greenport, belonging to the Montauk till member of 

the Manhasset formation, instead of to the Gardiners clay, representing, however, reworked and redeposited material derived from 

the Gardiners. At Brown Hills, northeast of Orient village, many 

indications of the presence of Gardiners clay were observed, 

although none of the exposures were fresh at the time of the 

writer's visit. Figure 73 shows one of the best exposures. The 

material is a tough, chocolate-colored clay dipping at angles as high 

as 80°. At the beach about 15 feet of the clay is exposed, but the 

base is not shown and. probably the actual thickness Is much 

greater, especially in the hills farFIGuRE 72.-Section near Jacob Hill. a, ther inland. 

Reddish to chocolate-colored Gardiners The conditions for observaclay; b, buff clayey Jacob sand; c, granitic gravels lying beneath overturned 

fold (Herod gravel member of Manhasset 

formation?). 

tions are best after severe storms. 

Mather, who examined the bluffs 

after such a storm on0ctober11 and 

12, 1836, found some remarkably good exposures, the most striking of which, illustrated in figure 61 (p. 93), shows a broad 

anticline of Gardiners clay flanked· with alternating sands and 

clays of the Jacob formation. The whole deposit is beveled L...------------lsFeet 

off and is covered by a clayey stratified till ("clay with iron FIGURE 73.-Section at Brown Hills, near 

crusts"), here referred to the ~1ontauk member of the Manhasset Orient. a, Chocolate-colored clay (Gardiforma tion. ners clay); b, gray sandy clay (Jacob sand). 

Robins JsZand.-Several fine exposures of the Gardiners clay may be seen on Robins Island 

between Great and Little Peconic bays. The best of these are near the north end of the bluff 

on the west shore, where there is 10 feet or more of dark-gray, 'greenish, or purplish clay inter-

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GARDINERS CLAY. 99 

mingled with a little sand and c~rrying a few small quartz pebbles and more rarely a granitic 

pebble. The beds are gently warped, in places rising 10 feet above the beach and in places 

sinking below sea level. Fa.rther south blue and· bro·wn clays, with flat clay concretions, are 

::e; ;;3,s~~e~~ta~:u<fi;~! ~ ------------ :.::-)C=-=::-=-::__~:~·::r·· r ~u~ ~ ~~e ~ctions ~&e .C~~~~~~~~~~~~-~~~~~~~~~~~~~~i~~~- was in 1904 a sharp nose showing buff and brown sandy clay, 

somewhat contorted and stand0 100' zoo Feet 

FIGURE 74.-Section on east side of Robins Island. a, Wisconsin till; b, buff contorted sand 

(Jacob sand and Herod gravel member of Manhasset formation); c, dark clay (Gardinersclay) .. 

ing at an angle of ·60° to 70°_. · The relations are shown in figure 75. Springs along the beach 

indicate the presence of clay near the surface at other points, but none was actually exposed. 

South· shore of Great Peconic Bay.-One ;mile east of )led Cedar Point, near Southport, a 

nearly black clay carrying the characteristic quartz pebbles of the Gardiners clay occurs near 

beach level. It lies beneath the red banded Montauk till member of the Manhasset formation, 

with which it is involved in vertical or _overturned isoclinal folds at two or more points. A 

third exposure was found in an abandoned clay pit a quarter of a mile east of Shinnecock Canal. 

The bottom of the pit appears t9 be a dark-gray to black plastic clay of the Gardiners type, 

grading upward at about the level of the floor of the excavation 

into a greenish-black clay full of pebbles representing reworked 

Gardiners material (Montauk till member). 

FIGURE 75.-Section on east side of Robins 

Island. a, Buff to brown contorted sandy 

c;lay (Gardiners clay); b, sand and clayey 

sand (Jacob sand); c, buff sand (Herod 

gravel member of Manhasset formation). 

The next exposure is about 1-! miles to the northeast, in the 

bluff of Sebonac Neck, near the south end of which is seen 

about 6 feet of a bright blue-gray clay weathering greenish and 

carrying small quartz pebbles irregularly distributed through 

the mass. It is interlaminated with a few thin streaks of red 

sand or reddish-brown clay and seems to be t~ue G~rdiners clay. 

I-Iog Neck.-Near the northwest point of Hog Neck several 

feet of folded greenish-blue fossiliferous clay was exposed in 

1904. The fossil shells, however, were much broken and the clay 

carries granitic pebbles, indicnting that it was reworked by the 

Montauk ice, although undisturbed Gardiners clay is probably 

not far below. 

Sag I-Iarbor.-Red clay, apparently representing the Gardiners clay, was noted in the 

n1ornine at several points southwest of Sag Harbor, and hns been worked on a small scale in 

times past. One exposure was seen in 1903 on a road through the moraine a mile west of the 

Sag Harbor and Bridgehnn1pton road. Gray, red, and greenish clays were seen in an old pit on 

a private road between the two highways mentioned. The clay lies 100 feet or more above sea 

level nnd is everywhere disturbed. Its position is apparently due to folding or shove by one 

of the ice sheets-presumably 

the Montauk. Some pebbly 

clays represent the parts reworked by the ice. 

Montauk.-Half n mile 

west of False Point, Montnuk, 

a good exposure .of the dnrk 

chocolnte-colored type of the 

0 100 zoo feet 

FIGURE 76.-Section half a mile west of False Point, Montauk. 

Gardiners clay was seen. Its relations are brought out in figure 76. ·Another exposure of 

clay, possibly Gardiners, having the relations shown in figure 87 (p. 107), was seen 1! miles 

southwest of Montauk Light, and a third exposure, showing upturned clay, was found about 

n. mile farther west. The thickness exposed was nowhere more than 15 feet, but as the whole 

of the formation was not seen the entire thickness may be much greater. 
100 GEOLOGY OF LONG ISLAND. 

. Garif,iners Jsland.--"-Gard4ters Is~and,.lying between th~ North and South flukes, is the type 

lo9~lity·fQr. the Ga;rdiners clay.. (See figs. 77to 81.) On its western shore a few feet of contorted 

redd~h clays interlami:p.ated with grayish-buff sand representing the top of the Gardiners clay 

. . was seen in a low bluff about a mile north of Great Pond, but it was 

riot observed agai!,l until a point half a mile east of Cherry Hill Point 

was reached. Here a succession of black, greenish (fossiliferous), and 

red· clays, -· merg- · 

illg upward ·into 

··. o 1s ·3ofeet Jacob sand and .___ __ __._ __ __, _::::: :.---

· FIGURE 77.-Section ncar Cherry 

Hill Point, Gardiners Island. a,, 

dipping 45 ° or 

. --- .... ,._-:_-_-:..:_ -· a,;..--- -- ----

. Black clay (Gardiners clay); b, 

greenish fossiliferous clays (Gardiners); c, red clay (Gardiners); d, 

buff sand and clay (Jacob sand); 

e, Wisconsin till. 

50° N.,. was exposed in gullies 

h h \ - . near t e S Ore .. FIGURE 78.-Section a quarter of a mile east of northwest end of bluffs on 

The occurrence northeast coast of Gardiners Island. a, Herod graval;-membcr of Manhasset 

· · · formation; b, fine gray Jacob sand; c, red Gardiners sJay. is illustrated in 

_figure 77 ,. which is .a. north-south section. Figure 81, representing a section 11ear the south 

end of Bostwick Bay, shows the. Gardiners clay banking against the Herod gravel mmnber in 

an overturned fold. Near the northwest end of the bluffs on the northeast side of the island a 

broad anticline (fig. 100, p. 110) brings up 

15 to 20 feet of red Gard.iners clay, and a 

little south is an ov~rturned anticlirie of 

red clay. The relations are shown in 

figure 78. Another exposure is shown in. 

figure 129 (p. 129). Complicated exposures occur at short ·intervals as far as 

Eastern Plain Pqint. One of these, showing upturned Gardiners clay, is represented in figure 79 and Plate XVIII, A. ,_a 

A. still more remarkable exposure is that -------------~------- FxGuRE 79.-Section three-quarters of a mile east of northwest end of bluffs on 

illustrated in figure 80, which represents northeast coast of Gardiners Island. a, Red Gardiners clay; b, gray clay and 

a bluff section about 1,350 feet long show- sand (Jacob sand); c, buff sand (Herod gravel member of Manhasset forma- . tion) .. 

ing six distinct anticlines, several of them . 

compressed. and inverted, involving the Gardiners clay. The heights of several of these are 

from 100 to 150 feet. The section figured by Veatch and shown here in figure 60 has been 

discussed on page 90. Several instructive sections are afforded in the bluffs at the south end 

zoo 400 

FIGURE 80.-Section near Whale Hill, Gardiners Island. a, Montauk till member of Manhasset forma-

. tion; b, Gardinersclay. 

o 20feet 

FIGURE 81.-Section near· south 

end of Bostwick Bay, Gardiners 

Island. a, Red clay, greenish 

along contact (Gardiners clay); 

b,sandandgravel(Herodgravel 

member of Manhasset formation). 

of. Tobacco Lot Bay, in one of which fossils were found in a greenish-black phase of the 

Gardiners clay similar to that at Cherry Hill Point. 

Plum Island.-On Plum Island, just northeast of Orient Point, the same general features are 

showi1 as on the neighboring parts of Long Island. On the north shore the Gardiners clay, 

although nowhere exposed above sea level, is everywhere near the surface, as is indicated by 

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. GARDINERS CLAY, 101 

the numerous exposures of Jacob sand. On the south shore the clay is brought to the surface 

at one or more points by folds. One of the best of these exposures was that seen near the 

southwest end of the bluffs~ . . .. _, 

where15.feet.of~hecla~with ~--·- · (!.<".._.,\\ .:-\-~>.i~~::~::::·->· .. ·· · .. ·. the rel~twns IndiCated 111 fig- ~ . =---::;==~ ·~~- -=:~~::~- ·~~:\ ure 82 1s brought up. · --·_,-_.:_~~-~->~ 

Fishe1·slsland.--:-The bes~ o ·so too· ·•so Feet··· · ·. ~. 

exposures of the . Gard iners FIGURE 82.-Section on south side of Plum Island. a, Wisconsin till; b, foiO.cd and faqlted beds of 

clay on Fishers Island (see fig. the Herod gravel member of Manhasset formation; c, brown to chocolate-colored clay with sand 

83) are at the clay pit Where laminm (Gardiners clay). 

the section shown in figure 84 was seen. The dip at the pit commonly averages 4S0 N., pointing 

to a fold of considerable n1agnitude, ·much greater than wiis ·supposed by Ries, who reported 

that the distur?ance extell(;led only to a depth of 20 to 30 feet.. That the fold.i:ng, is es'!=)enHally 

. . FIGURE 83.-Indcx map to localities on Fishers Island. Contour interval 20 fc!3t. 

superficinl is likewise believe.cl.by the present writer (see fig. 85), but, as indicated by figures 84, 

87 (p. 107), and 134 (p. 130), which are drawn to scale~ it_ is certainly much greater than was 

stated by Ries. The clay pit was started in ~ 

--------------, valley where the. clay showed at the surface, l;mt 

') it has been worked. back until now 10. to 30 feet 

of till or gravel has to be stripped off. The o~ter 

·or upper part of the material worked at .'the. pit 

is a brownish sandy clay interlaminated with sand, 

perhaps 40 feet thick. . The remainder is a dark 

-grayish blue to nearly black pJastic clay, with a 

50 Feet , .slight brownish tinge. No pebbles coulq be f()un·d 

FIGURJ<; 84.-North-south section at Clay Point, Fishers Island by the writer except in the lowest part of the 

(June, 1904). a, Wisconsin- till; b, Herod gravel member of Man. ,clay exposed, where a lens of granitic gravel WaS 

hassct formation; c, intcrlaminated sand and clay (Jacob sand); 'bl d h · · d, darK--gray to brownish-black plastic Gardiners clay. seen, pOSSl J ue. ~0 t · .e Incorporation of some 

of the underlying Jameco ·materials. No fossil 

· shells or leaves are reported. Some rounded clay concretions occur, and cl(mdritic markings are. 

found between some of the laminre. · . · 

Besides the inain 'folding there are many minor contortions which appe.ar to be due to 

movements of the clay layers over one another. The only point besides the clay pit at which 
102 GEOLOGY OF LONG ISLAND. 

·the Gardiners clay is well exposed is at Isabella Beach, where the sections represented in figures 

86'·.-and 106 (p.l12.) are to be seen. In the section shown in figure 106 the clay is 12 feet thick, 

and consists of alternating layers of gray and chocolate-colored silts, weathering to a somewhat 

darker color and dipping about 45.o N. At the locality of figure 86 the clays are exposed to a 

59ofeet 

FIGURE 85.-Generalized section of Fishers Island. a, Wisconsin till; b, Montauk till member of Manhasset formation; c, Herod gravel member of ·Manhasset formation; d, Jacob sand; e, Gardiners clay; 

!, Jameco gravel; g, Mannetto gravel (?); h, Cretaceous clay; i, light-gray granite. The separation of 

Jameco and Mannetto is hypothetical. 

thickness of more than 20 

feet, and occur in a broad 

trough coincident with a 

surface . valley.· Clay is 

said to have once outcropped near Clay Point 

on the north shore of the 

island, but there is now 

nothing but Wisconsin 

till to be seen in the low 

bluffs in that vicinity. 

In the base of the bluff forming the headland three-quarters of a mile northeast of the north 

end of Isabella Beach there is a few feet of greenish-gray clay, free from pebbles and similar 

to parts of the Gardiners clay, but its relations ~ould not be determined. (See fig. 135, p. 

130.) At no other point was the clay seen, the hills apparently being composed mainly of sand 

and fine graveL Any storm, however, is likely 

to alter the bluffs materially, and if the· clay is 

above sea level it may be exposed at any time. 

DEPOSITS PENETRATED BY WELLS. 

The details of the distribution of the Gardiners clay as shown by wells are summarized ·FIGURE 86.-Northeast-southwestsectionalongisabellaBeach,Fish 

in the following table, based on the records ers Island. a, Herod gravel member of Manhasset formation; b, 

Jacob sand; c, Gardlnersclay. 

obtained in connection with the water investigations. The correlations in general are the same as in the report on the underground waters, 1 

but in a few records, as in Nos. 71, 188, 258, 262, and 539, the writer from his study of the 

surface outcrops is inclined to make slightly different interpretations. Several exposures of 

clays that have been. reported considerably above sea level on the necks ofthe north shore and 

correlated with the Gardiners (Sankaty of Veatch) have been omitted from the table as more 

likely belonging to the Cretaceous. In many of the records the material classed as clay probably 

includes the Jacob sand, which can be differentiated only with difficulty in wells. 

Gardiners clay penetrated in wells of Long Island. 

No.a Locality. Owner or place. 

5 Brooklyn. . . . . . . . . . . . . Rapid Transit Co .................... . 35 ..... do ................ Forest Street and Evergreen Avenue .. 38 ..... do ................ Bartlett Street and Flushing Avenue. 

62 ..... do ................ TenEyck Street .................... .. 65 ..... do. .. . .. . .. . . . . .. . Porter and Maspeth A venues ........ . 136 Aqueduct ............. Brooklyn test well No. 17: ........... . 

Depth of 

formation. 

Feet. 

Character of the deposits. Correlation, with name used 

in original record. 

73-139 Clay .......................... Sankaty. 105- Blue clay. . . . . . . . . . . . . . . . . . . . . Sankaty or Cretaceous. 

87-127· Yellow or brownish sand and Sankaty. blue clay. 75-100 Blue clay..................... Sankaty? 48-190 ..... do........................ Do. 

95-106 Dark-gray clay (swamp de- Sankaty. posit). 141 EastNewYork ..... · .. BrooklyntestwellNo.5.............. 216-281 Graysiltyclay................ Do. 

176 North Beach ... : ...... Bowery Bay Building Association.... 32- 36 Blue and gray clay............ Do. 

187 Far Rockaway........ James Caffery......................... 42- 66 Clay.. .. .. .. .. .. .. .. .. .. .. .. .. Do. 

188 ... :.do ................ B.L.Carroll.......................... 45-65 Blueclay,withoutpebblcs.... Do. 

188 ..... do ..................... do................................. 20- 90 Blue clay and quicksand ...... Sankaty and Jamecc. 

191 ..... do ................ Queens County Water Co............. 60-100 Blue clay ..................... Sankaty. 193 1'hreemileMill. ....... T.R.Chapman ........................ 140-202 Darkclay,someveryhard.... Do. 

195 Aqueduct............. Shetucket pumping station........... 135-146 Gray clay..................... Do. 

·199 JamaicaSouth ........ Oconeepumpingstation.............. 115-185 Finegray.clay................ Do. 

200 ..... do ................ Baisley pumping station.............. 106-156 Blue clay and quicksand...... Do. 

a Numbers refer to well recor<1s in report on underground water resources of Long Island, New York, by A. C. Veatch and others (Prof. Paper 

U.S. Geol. Survey No. 44, 1906). 

1 Veatch, A. C., Underground water resources of Long Island, New York: Prof. Paper U. S. Geol.. Survey No. 44, 1906, pp. 168-337. " 

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GAPDINERS CLAY. 103 

Gardiners clay penetrated in 'Wells of Long Island.-Continued. 

No. Locality. Owner or place. 

201 Jamaica South........ Jmneco pumping station ............. . 

20:! ..... do ................ Brooklyn test well No. 1. ............ . 203 ..... do ................ Brooklyn test well No.2 ............. . 204 Springfield ............ Brooklyn testwellNo.3 ............. . 205 ..... do ................ Brooklyn test well No.4 ............. . 206 ..... do ................ Springfield pumping station ......... . 

212 Jamaica ............... Brooklyn test well No. 11 ............ . 213 ..... do ................ Pumping station Jamaica Water Supply Co. 

239 Whitestone ........... -Pumping station No. 1. .............. . 

241 ..... do . . . . . . . . . . . . . . . . Hailroad wells ....................... . 243 ..... do ................ W. W. Cole .......................... . 258 Hewlett Point........ G. B. Wilson ........................ . 259 Lawrence Beach ...... Bathing Association ................. . 260 Isle of Wight.......... John Lawrence ...................... . 261 Lawrence ............. D. D. Lord .......................... . 262 ..... do ................ A. W. Hart .......................... . 

273 HewlE;Jtt............... Queens County pumping station ..... . 

285 Valley Stream ........ Brooklyn test well No. 19 ............ . 295 Springland ............ Brooklyn test well No. 10 ........... .-. 

351 Plandome Mills ....... Robert Seizer ........................ . 374 Barnum Island ....... Poorhouse ........................... . 469 Dosoris ............... D. F. Bush .......................... . 

527 

528 

529 

530 

532 

539 

543 

545 

548 

549 

613 

628 

629 

671 

691 

801 

877 

880 

Oyster Bay .......... . ..... do ............... . ..... do ............... . ..... do ............... . ..... do ............... . ..... do ............... . ..... do ............... . ..... do .......... .-.... . ..... do .............. . ..... do ................ . 

~$~~t SJ~';.~ -~~~~~-::: .-.... do ............... . Muncie Island ....... . Bayshorc ............ . Port Jefferson ........ . New Suffolk ......... . Htlmpton Park ...... . 

Chas. Weeks ......................... . J. l\1. Sammis ........................ . Van Sise & Co ....................... . D. \V. Smith ......................... . E. K. Hutchinson ................... . A. J. & A. S. Hutchinson ............ . 0. L. Jones .......................... . '1:. Underhill. ........................ . Hamilton ............................ . William 'l.'rotler ...................... . 

~~'Wa~d~~-.:::::::::::::::::::::::::: Mrs. M. H. Clots ..................... . E. H. Muncie ........................ . Great South Bay Water Co .......... . J. L. Darling ......................... . Reid well ............................ . Mrs. S. F. McDonald ................. . 

881 ..... do ................ E. G. Whittaker ..................... . 

885 Shelter Ishmd ......... J. N. Steames ........................ . 

888 ..... do ................ A. 0. Ryder ......................... . 889 ..... do ................ Shelter Island Heights Association ... . 892 Greenport............. Waterworks ......................... . 901 Sag Harbor ........... J.. K. Morris .......................... . 907 Shelter Island......... Dr. Benjamin ....................... .. 

Depth of Character of the deposits. I Correlat.ion, with name used formation. in original record. 

Feet. 

78-144 Dark-gray clay, inclosing bed Sankaty. of yellowish sand. 

89-142 Gray clay..................... Do. 

83-154 Dark-gray clay or silty sand... Do. 

86-201 Fine gray silty sand and clay. Do. 

72-212 Gray clay..................... Do. 

65-170 Gray clay, with included bed Do. 

of yellowish-gray sand. 

95-189 Gray clay..................... Do. 

60-104 Blue clay..................... Do. 

25- 45 ..... do......................... Do. 

60- 85 Clay ..... :. . . . . . . .. .. .. .. . .. . . Do. 

1f>- 70 Clay and quicksand ........... Sankaty? 

65- Blue clay..................... Not correlated. 

25- 55 Clay.. . . . . . . . . . . . . . . . . . . . . . . . . Sankaty. 

40-100 Sand and clay................ Do. 

35- 70 Clay, fine gravel, and shells... Do. 

40- 70 G~~Ith c!~~lls~d white sand Sankaty and Jameco. 

54-115 Blue clay, green sand, and Do. 

quartz sand. 

72- 95 Yellowish-gray clay ........... 'Sankaty? 80- 94 Gray lignitic sand and blue Transition and Sankaty? 

clay. 50-100 Mud and sand ................ Sankaty? 75-113 Dark clay and lignite... . . . . . . Sankaty. 85- 95 Reddish sand, gravel, and Do. 

clay. 15- Clay ......................... . 30- 35 ..... do ....................... . 30- 53 Clay and sand ............... . 35-50 Clay ......................... . 35- 50 ..... do ....................... . 

~lt . g:~~ ~~~::: : : : : : : : :: : :: : : : : : : : 25- 80 ..... do ...................... .. 30-80 ..... do ...................... .. 10- 70 ..... do ....................... . 100-158 ..... do ....................... . 88-116 Blue clay .................... . 85-93 ..... do ...................... .. 45- Clay ......................... . 59-65(?) ..... do ....................... . 20- 40 Sticky brown to drab clay ... .. 4- 88 Clay ........................ .. 34- 80 Clay (part probably Montauk 

till member). 

Sankaty? 

Do. 

Do. 

Do .. 

Do. 

Wisconsin .and Tisbury . Sankaty? 

Sankaty. 

Sankaty? 

Do. 

Sankaty. 

Sankaty? 

Sankaty. 

Sankaty? Do. 

Cretaceous? 

Sankaty? 

Do. 

2- 82 Very thin.clay (part probably Do. 

Montauk till member). 

27- 35 Red and blue clay and white Sankaty. 

60-

60-

100-150 

100-132 

45- 60 

and red sands. 

Shells ........................ . Hod clay ..................... . Brown clay .................. . Gray or yellow clay .......... . Sand, with fossil shells ....... . 

Do. 

Do. 

Do. 

Sankaty?. 

Sankaty. 

The table brings out~the distribution of the Gardiners clay throughout Long Island, except 

over the higher Cretaceous areaf?, which were land masses during its accumulation .. In fact, 

indications of the clay are found in nearly all the carefully kept records of the deeper wells 

outside the Cretaceous areas mentioned, except near Springfield (No. 197), where the overlying 

transitional Jacob sand is represented. It is not. impossible that in some places, as at Port 

Jefferson, certain of the clays reported in the records may be Gardiners instead of Cretaceous. 

At the west end of the island, in Brooklyn and vicinity, the formation, which there consists of bluish clay with a few layers of yellowish sand or quicksand, is persistent with a thickness usually of 25 to 50 feet, although in places, as at Porter and Maspeth avenues (No. 65), 

much greater thicknesses of clayey material are reported. It is not improbable that the thickness of 142 feet given in this well record includes the Jacob sand and a part of the Manhasset 

formation and possibly a part of the J ameco and the Cretaceous. The character of the Gardiners clay in this. region is well brought out by the section of the well at Bartlett Street near 

Flushing A venue, which has been given on page 86. 

The formation in the region north of Jamaica Bay is described as a gray to almost black 

clay, in some places (No. 136) mixed with vegetable matter, suggesting salt-marsh deposits, 

and elsewhere (Nos. 295 and 374) carrying more or less lignite, much of it in the form of rounded 

fragments, as if derived from the reworking of the Cretaceous. Some greensand (glauconite) 
104 GEOLOGY OF LONG ISLAND. 

occurs mixed with the green clay near Hewlett and at Rockaway Ridge (No. 273) and fossils are 

found near Lawrence. A typical section of the ordinary nonlignitic type of the Gardiners clay 

in the ~amaica Bay region is afforded by the record of the Brooklyn.test well No. 3, Brooklyn 

Aqueduct and New York Avenue (No. 204), given in the discussion of the Jameco gravel on 

·page 87. 

The tripartite arrangement of the formation-a sand included between two clays-which 

is characteristic of the Gardiners clay on the island, is well brought out by this record. Its 

thickness in the region under discussion ranges from 11 feet near Aqueduct (Nos. 136 and 195) 

to 140 feet near· Springfield (No. 205). · The changes in thickness are very abrupt, as shown 

by a well (No. 197) half a mile east of No. 205, which shows·no clay whatever. The difference 

is due to a Cretaceous outlier at this point, which, though now buried by later glacial deposits, 

stood above the plane .of deposition of the Gardiners clay. At Far Rockaway, one of two 

adjoining wells (No. 188) showed clay a~ 45 to 65 feet, and in the other it was reported at 20 

to 90 feet. Similar differences occur elsewhere in the region, part being due to causes like the 

-one above described, part to differences in the amount of deposition, and part possibly to erosion 

by the Montauk ice or 'to stream or wave erosion in later times. 

On the north shore 14 feet of blue clay is reported at North Beach, west of Flushing Bay, 

20 to 54 feet near Whitestone, 5 to 60 feet near Oyster ~ay, and 8 to 58 feet on West Neck. 

In composition the clay is somewhat variable. Near Whitestone it is a blue clay associated 

with quicksand; at-Dosoris a.reddish-brown gravel and sand mixed with clay; at Oyster Bay 

a greenish clay with some sand; and at West Neck a blue clay. The Dosoris section, which 

is somewhat unusual as to materials shown but normal as to 1ts tripartite arrangement, is given 

below from \T eatch's report, with the writer's correlations. 

469. Record of D. F. Bush's well near Dosoris Pond. 

Recent: Feet. 

Yellowish-brown sand ..................... :........................................ 0 - 4 

~farsh deposit ........................ , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 7 

Montauk till member of Manhasset formation: Blue clay with pebbles ("hardpan")......... 7 -15 

Herod gravel meniber of Manhasset formation: Quicksand ............................... 15 -85 

Gardiners clay: . 

Reddish gravel and clay .......................................... ·. . . . . . . . . . . . . . . . . . 85 -88 

Very red sand ..................................................................... 88 -88! 

Reddish gravel and clay ............................................................ 88r95 

Jameco gravel: Light-colored gravel with a considerable percentage of glacial material; furnishes artesian water ......................................................... ·. . . . . . . . 95 _:97 

The wells of the north shore have in general yielded no fossils from the Gardiners clay. 

A "black marl" containing oyster shells identified by W. I-I. Dall as Ostrea 'oirginica was reported 

at a depth of.lS·feet, or abqut 80 feet above sea level, in a well on Manhasset Neck (No. 364), 

J?.Ortheast of.Port Washington, but from the information afforded by adjace11t wells and exposures 

in the bluff along the harbor it seems altogether improbable that the Gardiners clay is present 

at this elevation.. It is more likely that the.fossils belong to an old drift, probably the Montauk 

till member of the :Manhasset, and are of secondary rather than primary origin. 

Toward the east end .of the island the clays encountered in the wells are more reddish 

and are more commonly fossiliferous: . Red clays are reported from Shelter Island .(Nos. 885 

and 889) and Greenport (No. 892). Pleistocene fossils are found at Quogue (No .. 859), at 

Shelter Island -(Nos. 888 and 907), and at Bridgehampton (No. 897). Clays are encountered at 

New Suffolk (No. 87.7), at Hampton Park (Nos.· 880 arid 881.), and near.Sag Harbor (No. 901). 

In thickness the clay ranges from a few feet on Shelter Island to .. 50 feet at Greenport, 84 feet 

at New .Suffolk, and 80 feet at Hampton Park. 

AGE. 

Two lines :of .evidence bearing ·on the·age of. the Gardiners clay are available, the· first being 

their fossil content and the second the character of the immediately overlying and underlying. 

beds. 

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GARDINERS CLAY. 105 

The fossils of glacial formations are either prin1ary-those whose position and condition 

are such as to indicate growth in place; secondary_.:those that have been picked up and redeposited by the· ice; or tertiary-those that were taken up first by the ice and later by water 

before being. redeposited. All three kinds are represented on Long Island and great care is 

needed in discriminating them. Fortunately, those found in the Garcliners clay in most localities show features that indicate unquestionably their primary character. 

Shells of "clams, oysters, _razor fish," etc., have been repeatedly reported from ·wells on 

Rockaway Ridge and elsewhere on western Long Island in materials associated with the clay, 

generally in a sand stained black by organic matter found at the base of the clay. As they 

hn.ve.been found in wells, their occurrence can not be actually observed, but their presence in a 

sand carrying lignite and greensand and thoroughly stained with organic matter, in shqrt 

possessing the characteristics of sanely marine flats, points strongly to their occurrence in place. 

At Fort Hamilton, facing the Narrows at the entrance of New York Bay, Nassa obsoleta, 

Cre1Jidula fornicata, · Mytilus edulis, Anomia ephippium, · Mya arenaria, and Solen ensis were 

reported as being obtained from the Garcliners clay (Sankaty of Veatch) in a well sunk at this 

point~1 

_At Bedford, according to Redfield 2 and Desor,3 were obtained Ostrea, Venus mercenaria, 

P11..rpura lapillus, and Baccium obsolet1.tm. 

• A specimen of Ostrea virginica was obtained from a well on Manhasset Neck at an elevation 

of 80 to 100 feet above sea level, but. it is evidently of secondary origin, unless the clay has been 

brought to an entirely abnormal and unusual height by the ice shove, which is regarded as 

improbable. The· clam and oyster shells obtained near the bottom of a 40-foot layer of blue 

day, at a depth of 60 feet below sea level, in a well near the end of the point (No-. 368), were 

probably in i)lace . 

A "marl bed containing oyster shells" is reported as occurring in a well on :Main Street, 

Oyster Bay, at a depth of 45 feet, or 35 feet below sea level.4 

:Many writers, including Samuel L. Mitchill in 1800, 1813, 1814, and 1818, Tilnothy Dwight 

in 1821, John Finch in 1824, W. W. Mather in 1837 to 1843, Gabriel Farnum in 1875, Elias 

l..~ewis in 1877, Warren Upham in 1879, and F. J. H. Merrill in 1886, have recorded fossil shells 

fron1 wells and other sources mainly in the western part ?f the island at horizons corresponding 

to that of the ·Gardi,ners clay. (See bibliographic review, pp. 4-22.) Of these writers, Lewis 

alone notes the occurrence of shells in wells, the fossils observed by the other writers -being in 

llrift of shallow. and possibly post-Wisconsin deposits. The wells noted by Lewis were at Flatbush, Prospect Park, Bath, East New York, Farmingdale, and Amagansett. In-the field work 

for the present report shells of Pecten were reported in two wells at Hampton Park (Nos. 880 

and 881). · · 

The best exposures of fossiliferous strata are found on Gardiners Island, two localities yield.: 

ing shells in place. One of these localities is just east of Cherry Hill Point, the western extremity 

of the island. A diagram of the beds at this place is-shown in figure 77 (p. 100). The thickness of the strata ·from top downward· are as follows: .. t. 

_Section ?f ~~~siMJ;;.~us series ne~r Cherry Hill Point. 

• . Feet . 

·Wisconsin: Till resting conformably across edge Of following bed.; .... :: .. ; .. -"-.:·: .......... ~. 2 

.. Jacob sand: Sand and sandy clay in alternating layers._,_ ...... : .. ~ .......... ·.................. 5 ' l 

Gardiners clay: •r•', 

Red.clay with a little lignite .......... , ...... ·.......................................... 15 

Greenish clay with Pleistocei1idauna in place ............... _· ·_ .. .. . . . . . . . . . . . . . . . . . . . . . . . 10 

Black clay with organic matter, exposed ...•... ; .....•................................ -... 3 

1 Veatch, A. C., op. cit., p. 168. ·. · · ·~ 

2 ~~·Jour. Agr. and Sci., vol. 61 1847, pp. 213.:219; Am. Jour. Sci., 2d ser., vol. _5, 1848, pp. llQ-111; Proc. Boston Soc. Nat. Bist., vol. 4, 1854, 

p. 181. . 

3 Proc. Boston Soc. Nat. Hist., vol. 2, 1848, p. 247; vol. 4, 1854, pp. 18()-181. 

• Woodworth, J. B., Bull. New York State Mus. No. 48, 1901, p. 661. 

.... ,f. 
106 GEOLOGY OF LONG ISLAND. 

The fossils collected by Veatch at this point were· i.dentified by Dall as Area crenella, 

Modiola sp., and Oyprina islandica Gmelin. Considerable numbers of each- of the forms occur. 

On Shelter Island shells were reported in great variety at a depth of 60. feet in the well 

of A. 0. Ryder. At Quogue, on the south side of Long Island, fragments of shells brought up 

from a depth of 135 feet in the well of A. B. Hallock (No. 859) _were exami.ned by Dall, who 

states that the material contained "fragments of :Mulina, Astarte, an unidentifiable bivalve, 

a specimen of Nassa trivittata Say, and fragments of an echinoderm. This is prob.ably 

Pleisto~ene." Pieces of shells embedded in greenish clay (the usua~ character of the fossiliferous part of the Gardiners clay) were brought up from a depth of 100 feet in the well of 

Sanford & Son at Bridgehampton (No. 897). 

Broken shells of species now existing were found about one-fourth of a mile south of the 

north end of the bluffs on the west side of Hog Neck, 3 miles northwest of Sag I-Iarbor. They 

occurred in a greenish-blue clay, which, however~ contains a few erratic pebbles, indicating 

that it has been reworked by the Montauk ice. Although strictly speaking they are in till, 

there is practically no doubt that they were derived from the Gardiners clay of the immediate 

. vicinity. Small fragments of broken shells were seen in the Hempstead gravel member of the 

Manhasset formation at one or more points but are apparently of secondary or_ ~ertiary 

origin. 

From the distribution of the fossils it will be seen that they constitute a persistent feature 

of the Gardiners clay, occurring at all levels from the transitional basal sands, as at the Rockaway Ridge locality, to the middle, as at Gardiners Island .. They also occur in the sands 

above the clays on Gardiners and Robins islands and Nantucket, a fact which would seem 

to indicate that the conditions were very similar throughout the period of accumulation, being 

in fact not very different from those existing on the southern coasts of New England 

to-day.· 

Besides the fossil shells, ligni.te and other forms of organic matter are of common occurrence in the Ga!diners clay, especially near the west end of the i.sland, and are found in sn1all 

amounts as far east as Gardiners Island. In some places the black muck brought up from 

wells so closely resembles the muck of the present bays in color, texture, and odor that the 

two are practically indistinguishable. Some of the lignite is rounded as if rolled about by the 

waves, indicat~g an origin at sea level. It is thus seen that parts of the deposits have a close. 

resemblance to salt-marsh or shallow-lagoon deposits. 

Lignite and other woody materials were reported by many of the early investigators as 

occurring in the wells of western Long Island at horizons not far from that of the Gar~iners 

clay. Probably some of these materials·, especially the true lignites, are from the Gardiners 

clay, but it seems .likely that many of the fresher fr_agments described as wood, tree trunks, 

branching trees, etc., are younger, probably representing soil zones of the Vineyard interglacial stage. . 

The Gardiners clay,· as indicated by its fossils and its wood and lignitic content, muck, etc., 

must undoubtedly be regarded as an interglacial deposit. Below it lies the Jameco gravel, 

which, as has been stated, is probably of glacial origin, and above it is the great Manhasset 

formation (preceded by the transitional Jacob sand), consisting of unfossiliferous gravels with 

a thick intercalated till member (Montauk), all of which are likewise thought to be of glacial 

derivation. If the tentative correlation of these glacial formations with the Kansan and 

Illinoian glac!al stages should prove correct, it would fix the time of the Gardiners clay a3 corresponding to the stage known in the interior of the country as the Yarmouth interglacial stage. 

JACOB SAND. 

NAME. 

The Gardiners clay grades upward through interlaminated clays and sands into. fine silty 

sands. When wet many of-these sands are somewhat plastic and show a pinkish tinge due to 

their clay content, which gives them a certain ·resemblance to the Gardiners clay. Although 

their deposition followed without. a break that of the Gardiners clay, they nevertheless sl~ow 

sufficient lithologic difference from that formation to pern1it their recognition throughout 

.. 

-· 

•. 

• 

-· 

-. 

-· 

.. 
~· 

• 

.. 

.. 

JACOB SAND, 107 

Long Island and the islands farther east. Their lithologic characteristics, marking a distinct and 

persistent change in the conditions of deposition, entitle the beds to recogni~ion as a separate 

formation. 

To this formation the name Jacob sand has been applied, from Jacob Hill, a high point on 

the north shore of Long Island, 8 n1iles northeast of Riverhead, near which the formation is 

well exposed. · CHARACTER. 

In its most characteristic form the Jacob sand consists of exceedingly fine sands, mainly 

quartz flour, but with many grains of white mica and some of dark-colored n1inerals. In color 

the sands commonly range from a very light gray t<;> yellowish and buff tints, but where laminre 

of true clay are present they may be stained reddish externally. They are everywhere clearly 

. stratified, although individual beds several feet thick and appearing structureless to the eye are 

encountered. When wet most·of them are somewhat plastic but lack the toughness of true 

clay; all are decidedly gritty to the teeth and most of them to the touch. Interbedded with the 

fine varieties of the Jacob deposits are some more distinctly sandy beds, usually buff or yellowish, and several feet thick, in which particles of fairly fresh granitic minerals can be recognized. 

SOURCE OF MATERIAL. 

Whether the gradual.change from plastic clays to the exceedingly fine, claylike quartz sands 

of the Jacob formation·was due to a change in level, to a change in direction and strength of the 

currents, to the advent in the region of the finer materials from the outwash of an advancing 

ice sheet, or to a combination of all these factors, can not be stated definitely. 

Perhaps the best clue to the source of the material is afforded by the general sequence of the 

deposits. Following the fine plastic Gardiners clay, whose character indicates, in all probability, 

a very slow accumulation under conditions of scanty supply, the Jacob sand affords indications of increased supply and more rapid accumulation, and t.he succeeding Herod gravel 

n1ember of the Manhasset formation affords evidence of still more rapid deposition and the 

near approach of the ice sheet associated with the Montauk till member of the Manhasset. In 

other words, the Jacob sand seems to mark the first influx of new material on the advance of 

the ice sheet, bringing to a close the interglacial stage characterized by the Gardin~rs clay. 

RELATION TO OLDER DEPOSITS. 

As previously noted, the Jacob sand in many places merges by insensible gradations into the 

Gardiners clay, although elsewhere the sand gives way to the clay more abruptly. It has not 

been seen in contact with beds older than the Gardiners, but it must overlap the Mannetto or 

Cretaceous at many points below sea level. 

CHARACTER OF THE UPPER CONTACT. 

Toward the top of the formation the beds grade upward into medium and then into coarse 

sands, which in turn give way to the Herod gravel member of the Manhasset: These upper 

sands are buff in color and in places reach a thickness of 15 to 30 feet. It is possibly in a sandy 

layer of this type that the fossils found . 

in the bluffs op. ·the shores of Great 

Peconic Bay, 2 miles west of the Shinnecock Canal, occurred. (See fig. 117, 

p. 126.) 

Owing to local nondeposition of 

4he Herod gravel member, or more 

-commonly to erosion by the ¥ontauk 

ice, the Montauk till member of the 

Manhasset formation in places rests 

o· 100 zoo Feet 

FIGURE Si.-Section 1~ miles southwest of Montauk Light. a, Banded Montauk 

till member of Manhasset formation; b, Herod gravel member of the Manhasset; 

c, contorted clayey Jacob sand; d, dark chocolate-colored clay interlaminated 

with white sand, possibly representing the Gardiners clay. 

directly upon the Jacob sand. Generally the bedding of the sand and till is conformable, but in 

a few·places the Montauk rests on upturned or folded Jacob beds, which have l~cally been more or 

less eroded. This is brought out in figure 59 (p. 89) and especially in figure 87, which shows the 
108 GEOLOGY OF LONG ISLAND. 

Montauk member resting on the disturbed or eroded Jacob sand. Both the folding and the 

erosion, to judge from the contour of the resulting surface, seem to have been due to ice, presumably to the same sheet that later deposited the 9verlying Montauk till member. · The unconformity due to erosion in many places amounts to many feet and differs from place to place. 

At some points the work of the Montauk ice sheet was wholly erosional, there being no deposition of drift, and at such places the overlying Hempstead gravel member of the Manhasset may 

rest di:t;ectly upon the Jacob sand. Where the Montauk rests upon the sand considerable 

quantities 0f the sand have been incorporated in it, giving it a noticeably silty texture, which 

has been a potent cause of the characteristic cementation of the till. As in the Gardiners clay, 

there are all gradations between the undisturbed deposits through reworked Jacob sand into 

silty till. 

STRUCTURE. 

What has already been said as to the structure of the Gardiners clay applies with equal 

force to the Jacob sand. Though classed as sand, its texture was so fine and it· contained so 

much silt that it behaved like clay under the a9tion. of the overriding ice, being bent, foldedi · 

crumpled, and overturned instead of crumbliAg and di$jntegrating as the coars~r sands. and. 

gravels commonly did. Lying stratigraphically higher, and hence nearer the surface, it was 

more subject to disturbance than the Gardiners clay ai1d has been exposed at more places along 

the coast. The Jacob sand, like the clay, is most disturbed along the north coast, especially 

near the east end of the island, exhibiting more gentle folds in the southern part. Most of the 

folds trend approximately east and west, altho~gh on the sides ()f the bays the lateral thrust 

has in places, as at Port Washington, produced folds with north-south axes. Details of the 

folding are given in the section on distribution below. 

DISTRIBUTION. 

SURFACE EXPOSURES. 

The distribution of the Jacob sand on Long Island is in general the same as that of the 

Gardiners clay, although from its position above the clay it is more exposed. · 

College Point.-The most westerly outcrop noted was at the base of the bluff between College 

Point and Tallman Island, where several feet of fine light-gray micaceous sand was exposed in 

1904 near tide level in a nearly horizontal position. 

Port Washington.-The next locality toward the east at which the Ja;cob sand was seen is 

near Plum. Point, on the east side of Manhasset Bay, 1! miles northwest of the town of Port 

. Washington. At many points near and at the 

bottom of the immense abandoned gravel pit at 

the base of Plum Point the Jacob sand was formerly to be seen, limiting the depth to which 

gravel and sand (Herod member) could be taken 

FIGURE 88.-Section"northof.Weeks Point, Hempstead Harbor. a, Wis- out. . The exposures in this pit at the time of the 

consin; b, M:ontauk till member of Manhasset formation; c, contorted · writer's visits, in 1903 and 1904, did not admit of 

Jacob sand. 

a determination of the structure of the forma.;.. 

tion, but in a similar pit near the shore_about a quarter of a mile southeast a fine pinnacle of liglit:.. 

gray, highly contorted clayey·sand was seen. 

Hempstead Iiarbor.-The Jacob sand is exposed at many points on the east side of Hempstead Harbor. A little n9rth of Weeks Point; about 1! miles. northwest of Glen Cove, a sharp 

fold of Jacob sand rising 20 .feet above the beach and having a breadth of about 40 feet was seen 

(fig. 88). Between Red Spring Point and Glen Cove Landing the sand was observed at several 

places, and still farther south, near Glenwood Landing, a pinnacle of light-gray Jacob sand' 

rising about 10 feet above the floor of a large gravel pit (Herod gravel member) was seen. 

Oyster Bay.-The Jacob sand was exposed in 1904 at the top of the bluff at Rocky Point, 

2 miles north of the town of Oyster Bay. The bed was very thin and in .places had been entirely 

removed by the Montauk ice (fig. 65, p. 96). An exposure of Jacob materials is also reported 

at the extreme southwest point of Center Island, and the sand of the same formation was again 

seen in the beach below high-tide level near the west end of Coopers Bluff, northeast of the town.· 

.. 

.• 

• .. -

.,. 

• 

., 
.• 

.• 

.. 

·" ·, 

.. 

.... 

.,. 

.. 

•. 

,. 

J 

JACOB SAND. 109 

Lloyd and Eaton necks .-On Lloyd and Eaton necks the Jacob sand appears to be either below 

sea level or to have been. removed by ice erosion (Montauk), the drift of this sheet generally 

.___ ____ __, so Feet 

resting directly 

upon the Cretaceous. 

Northport to 

Port Jefferson.-

Tbroughout. the 

stretch of nearly 

15 miles east 

from Northport 

FIGURE 89.-Section a quarter of the JaCOb Sand o sofeet '------------------------~ 

a milo west of Hallock Land- 1· 

ing. a, Herod gravel member appears to 1e FIGURE 90.-:-SectionnearWoodville Landing. a, Upturnedsandandgravel (Herod . of Manhassctformation(struc- below sea level. gravel member of Manhasset formation); b, contorted and folded Jacob sand; c, till. ' 

ture not shown); b, contorted At the only place . grayclayey sands( Jacob sand). 

where the lower beds are seen, which is on the coast 3 miles northeast of 

Northport and about a mile north of the village of Fort Salonga, the Jacob and associated beds 

appeared to be absent, the Montauk till member 

resting immediately upon the Cretaceous clays. 

FIGUitE 91.-Section at landing west of 

Jacob Point. a, Banded clayey till 

(Montauk till member of Manhasset 

formation); b, pink till, gray clay, and sand (Jacob sand). 

Port Jefferson to 

Wading River.-Beyond Miller Place exposures are fairly common. The first good 

outcrop seen was a 

quarter of a mile west 

of Hallock Landing(fig. 

'o 100 zoo Fee{ ~------------~------------~ 

FIGURE 92.-Section near Jacob Hill. a, Till; b, Herod gravel 89), where the clayey member of Manhassc·t formation; c, upturned and contorted 

sands are upturned at pinkish to buff clayey Jacob sand; d, former extension of bluff. 

Relations to sand not shown. 

a high angle because of 

both folding and faulting. Two miles farther (about half a 1nile east of Woodville Landing) highly 

c 

---- =--

0 so Feet 

FIGURE 93.-SectionatJacob Hill. a, Dune sand; b, band- . cd Montauk till member of Manhasset formation; c, 

brown clayey Jacob sand; d, buff clayey Jacob sand 

(poorly exposed). 

disturbed sands of the Jacob type are again seen (fig. 90) . 

Wading River to Orient Point.-For the next 10 

miles the Jacob sand is not exposed, being below sea 

level along the bluffs. It first reappears in upturned 

and contorted masses a little east of Roanoke Landing, 

north of Centerville (fig. 71, p. 98). Two miles east, at 

the landing west of Jacob Point, the Jacob sand is 

nearly on end in a small ravine (fig. 91) and at several 

points along the 

beach for threefourths of a mile 

or more, beyond 

which it again 

sinks below sea 

level. It was 

next seen 2! 

miles farther 

east, in the bluff 

at Jacob Hill, 

where great pinnacles composed 

0 .roo Feet 

FIGURE 94.-Section at Brown Hills, near Orient. a, Gray to buff sands (relations to clay not clear, but proba- blythe same as in fig. 97); b, dark clay (Jacob sand); c, yellowish upthrust sands (Herod gravel memher of 

'Manhasset formation). 

of Gardiners clay and Jacob sand stand out from the bluff (fig. 92). Still better expo-

~ures, however, were found a quarter of a mile farther- on, where some 60 feet or more of 
110 GEOLOGY OF LONG ISLAND. 

brown and buff clayey sand or sandy clay of the Jacob type is exposed (fig. 93). In the 20 miles 

or more of coast between this locality and Orient Point the Jacob sand is exposed at only one 

place-in the bluffs of Brown Hills, northeast of Orient village. 

Here the exposures are much the same as at the point last 

FIGURE 95.-Section at Brown Hills, near Orient. a, Dune 

· sand; b, Wisconsin till; c, sand and gravel (Herod gravel 

member ofM.anhassetformation); d, very fine disturbed · 

clayey sands (Jacob sand) standing out in detached 

masses. Relations probably the same as in figure !li. 

described, the sands being ·highly disturbed, 

folded, and contorted. 

Something of the present 

character of the outcrops 

and the unconformable 

relation of the overlying 

sand is shown in figures 

94, 95, 96, and 97. 

Robins and Shelter 

islands.-South of the 

J) 

..... 

9._~-------':"¥'. Feet 

FIGURE 96.-Section at Brown Hills, near 

Orient. a, Till (Montauk till member of 

Manhassetformation); b,grayclayey sands. 

North Fluke the Jacob sand is well exposed on Robins Island, where it occurs on the west 

side, about 500 yards south of the north end of the cliffs, both in broad open' folds and in 

=.o:~:·.:~·a.:·~ 

~c -~t~\~f~l1'' 

0 50 . IOOF'eet 

FIGURE 97.-Section at Brown Hills, near Orient. a, Till; b, 

Herod gravel member of Manhasset formation; c, disturbed 

clayey Jacob sand. 

highly upturned masses, like those shown in figure 

74 (p. 99). Fossils occur in the bed shown in figure 

98. :The Jacob sand appears to be penetrated by 

wells on Shelter Island but 1s Iiot clearly developed 

above sea level. 

FIGURE 98.-Section on west side of Robins Island. a, Till; b, 

folded buff sand (Herod gravel member of Manhasset formation); c, thin layer of cemented gravel; d, gray clayey Jacob 

• sand, with fossils at e. 

Gardiners Island.-On Gardiners Island the Jacob sand is abundant, occurring in many. 

places and reaching thicknesses of 20, 30, and perhaps 50 feet. Evidence of local and temporary 

~~{{{~:~!~~~~{,~A-~ !?f:d~~ ~~~:.o~:;sa:~=at~; !~f~:;:no~~:~:h 

.~ :~ The Jacob formation,· consisting of alternating 

FIGURE 99.-SectionhalfamilenorthofCherryHill Point, day and fine sand, was seen above the red clay at the 

Gardiners Island. a, Herod gravel member of Manhasset fossil locality east of Cherry Hill Point (fig. 77' p. 100). 

formation; b,finegrayripple-markedJacobsand. Half a mile north of the point the Jacob in the form 

of finely stratified gray sand with ripples (a common phase on 

Gardiners Island) was seen in nearly horizontal beds (fig. 99). 

Near the north end of the cliffs: on the northeast shore it is 

so' ...... 0 ~o .• .. . involved in both 

open (fig. 100) 

and overturned 0 2ooFeet L--------'L------~ 

FIGURE 100.-Section near west end of bluffs on 

folds (fig. 78, p. northeast shore of Gardiners Island. a, Red 

0 a b 100). A quarter Gardinersclay; b, gray clayey Jacob sand. 

FIGURE 101.-Sectionshalfamileeastofwestendofbluffsonnorth- of a mile southeast it is again seen in overturned east coast of Gardlners Island, showing' fine gray folded Jacob 

sandoverlainbytill. folds. (fig. 101 a, b), and 350 paces farther in the 

~arne direction it is involved in the highly contorted mass shown in figure 79 (p. 100) 

and Plate XVIII, A;the bedding being practic~lly vertical. Other exposures are shown in 

figures 1.29 and 130 (p. --). The Jacob sand continues in constant· association with the 

_ .. 

.. 

... 

.. 

·• 

,. 

.... 
l 

' 

, 

I 

U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 82 PLATE XVIII 

A. UPTURNED GARDINERS CLAY AND JACOB SAND ON EAST COAST OF 

GARDINERS ISLAND. 

B. OVERTURNED FOLD OF JACOB SAND LYING ON HEROD GRAVEL MEMBER 

OF MANHASSET FORMATION, EAST COAST OF GARDINERS ISLAND. 
r 

'·JI 

I ,, 

t.' 

~ 

1 ~-

JACOB SAND. Ill 

Gardiners clay in the 1,350-foot section represented in figure 80 (p. 100), near the end of 

the bluffs toward Eastern Plain Point. The details of one of the overturned and recumbent folds in this section are shown in Plate XVIII, B. The Jacob sand occurs here and 

there in the bluffs bordering Tobacco Lot Bay, but the beds are so contorted, faulted, and· 

otherwise broken up that they 

\~ 

\ 

I 

I 

\ 

\ 

I 

form a confused 

jumble, the relations of which- it 

would take weeks 

to work out in detail. Fossils occur 

0 100 Feet 

FIGURE 102.-Scction half a mile west of landing, Plum Island. a, Till; b, Herod gravel 

in the JaCOb at one member of Manhasset formation; c, fme micaceous contorted Jacob sand. 

point. 

South Fluke.-The Jacob sand is comn1only absent on the South Fluke, 

owing to erosion by the Montauk ice. It occurs, however, at several points on 

Montauk peninsula. A mile west of Rocky Point, on N apeague Bay, contorted 

sand, possibly the Jacob, is present near the top of the b]uff (fig. 126, p. 128). 

Half a mile west of False Point, nouthwest of Montauk Light, sands and gravels 

are seen between the Garcliners clay a1;1cl the Montauk till member of the 

Manhasset . 

formation, 

probably 

representing 

'the conlbinecl Jacob 

sand and 

Herod gravel 

0 50 1oo Feet 

~--------~---~---J 

FIGURE 104.-Section east of Fort Terry, south side of Plum Island. a, Montauk till member of 

Manhasset formation; b, Herod gravel member of Manhasset formation; c, brown to reddish clay 

interlaminated with sand (Jacob sand). 

member of the Manhasset (fig. 76, p. 99). Two n1iles east of Ditch Plain life saving 

station beds of fine sand interlan1inatecl with chocolate-colored clay are seen resting on a series of greenish-gray sands and fine yellowish gravels, the whole being 

1nuch eroded and overlain in turn by the Montauk till member (fig. 59, p. 89). 

This might be either an overturned and recumbent fold of Jacob sand upon the 

Herod gravel men1ber or a sandy phase of the Garcliners clay resting on Jan1eco 

gravel. The former is regarded as the more probable. A n1ile and a half southwest of Montauk Light there is some highly disturbed and folded Jacob sand 

. having the relations shown in figure 87 (p. 107). 

Plum Island.-The Jacob sand is seen below the Herod gravel member in 

a b r o a cl , 20 'r--:~-;-:--;-;--:c:-:-:--::--:-~=-------::-::-:-.----

~':e "::!1£ ; ~ ~.: f; ~ ;;,\{;?,;;;;:!-B. ; f < ~-;) .::\;·.-~':"-'.:.-.:~-~.-.;;·-.~-f.-::',....·<?~.~- .. -.. :-=-:;:'-==.-~:-::~~=. :-=-~.o~:· ?7:" .• -.. ;:~.~:::-~71~. 

a m i I e 

~est of 

the Plun1 

Island 

Ian cling o "--------------------------~ (fig. 1 02)' FIGURE 105.-Section east of Fort Terry, south side of Plum Island, showing part of overturned fold in 

clayey sands (Jacob sand ?). 

IJ.l and at in-

~ · tervals fron1 this point to the lighthouse. It is everywhere disturbed, the bed- ~ cling standing in places at an angle of 50°, and it probably occurs in a succession 

of folds sin1ilar to that illustrated. On the south of the island it is seen involved in broad, low 

folds from the west end of the bluffs to Fort Terry (fig. 103). About half a n1ile east of the fort 

it appears to be involved in several overturned and recumbent folds, having the relations shown 

in figures 104 and 105. 
112 GEOLOGY OF LONG ISLAND. 

Fisher_s lsland.-The best exposures of the Jacob sand on Fishers Island are to 'be seen in 

the clay pit and in the sections at Isabella Beach. In the pit (fig. 84, p. 101) there is 40 feet of 

brownish sandy clay interlaminated with sands and overlying the darker and more plastic 

. Gardiners clay into which it grades. At one of the Isabella Beach localities the Jacob sand 

is represented by 15 feet of fine gray clayey sand (fig. 86, p. 102). At the other about 35 feet 

<:>._ _____ ....=.so Feet 

FIGURE 106.-Bluff section at Isabella Beach, 

Fishers Island. a, Wisconsin till; b, gray 

clay belonging to .Jacob sand; c, gray sand 

belonging to Jacob sand; d,grayclaybelonging to Jacob sand; e, gray sand belonging to 

Jacob sand; /, chocolate-colored and gray 

clay (Gardiners clay) .. 

of the Jacob appears with the top unexposed (fig. 106); the 

lower 15 feet is of the usual gray-green clayey-sand type, but the 

upper 20 feet approaches ~ gray sandy clay in character. ·In 

an artificial cut near the steamboat wharf on the west side of West 

Harbor a. considerable amount of grayish clayey sand of t4e 

Jacob type is exposed, as shown in figure 173 (p.147). The relations shown in the right-hand half of the figure, particularly the 

upturning and unconformity, are especially characteristic of the 

conditions at the Jacob stage in Long Island and farther east; 

but nowhere else, save at Sankaty Head, Nantucket, has a gravel 

been seen interbedded with the sands, as shown in the lefthand part of the figure. There is also somewhat less of the old 

look characteristic of most exposures of the drift of this stage, 

but this may be due to the freshness of the artificial exposure. 

The topography, moreover, has a distinctly pre-Wisconsin 

aspect, and the overlying till resembles the Montauk member rather than the Wisconsin.. For 

these reasons it seems probabl~ that the clayey sands are to be referred to the Jacob sand. 

Along the base of the bluff on the south side of the high hill s~:mth of West Harbor a thickness of 10 feet of pinkish and brown sandy clay alternating with laminre of sand is exposed in a· 

low anticline about 100 feet across and a few feet high .. This belongs without doubt to the 

Jacob sand. · DEPOSITS PENETRATED BY WELLS. 

I 

Because of tp.e extreme fineness of. the sand and the admixture of more or less clay it is very 

difficult to differentiate the Jacob sand from the Gardiners clay in drilled or dri~en wells, or 

those sunk by the jet process, and although surface- exposures prove that the formation is 

fairly persistent throughout the whole of Long Island, it appears to have beer ... recognized as a 

distinct bed in only· a few wells. In most of the well records it is doubtless included in the 

Gardiners clay. Some of the records, with correlations of the writer, are given below. 

Probably the best record is that of a well near Hewlett Point, at the west side of the entrance 

to Manhasset Bay. 

258. Record ojG; B. Wilson's well, near Hewlett Point. 

Recent: Feet. 

Dug weli (fresh water, slightly hard) ............................................... . 0-14 

Beach sand ...................................................................... . 14-20 

Montauk till member of Manhasset formation: 

Light-colored clay with stone .... _ ................................................. . 20-30 

~~~;~11~~: ~ _- _-_-_ -_ -_ ~: ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ : : ~ ~ ~ : : ~ ~ ~ : : : : ~ : : : : : : : : : : ~ : : : : : : : : : : : : : : :·: : 30-32 

. 32-36 

Herod gravelmemberof Manhasset formation: Coarse gray sand containing· salt water at 46_ 

feet and brackish water at 59 feet. __ .... _. __ ... -- .. - . -.... __ . __ .. ---- ........... . 36-59 

Jacob sand: 

Alternate layers of sand and clay ................................ : ..... -............. . ,59-63 

Yellowish sand ............................................................ _ ...... . 63-65 

Gardiners clay: Blue clay ................................ ~ .................... -... -- ... . 95-

Jameco gravel: 

Fine yellow and grayish sand ....................................................... . -103 

liard pan ............. _ . ____ .... __ .... ____ .. __ . _ ... __ .... __________________________ _ 103-105 

Yellow gravel with fresh water .................................................... . 105-108 

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JACOB SAND. ·113 

The record of a well on the Dodge estate, near Port Washington, is of interest as showing the 

tendency to identify the Jacob as a clay. There is little reason to doubt that the dry yellow 

clay of the record represents the Jacob sand, for the Gardiners clay, so far as known, is nowhere 

yellow, whereas the Jacob sand is in many places buff or iron stained. 

966. Record of well of Dodge estate, near Port Wash~ngton. 

Feet. 

Wisconsin: Yellow stony loam. ______________ . __ . _____________________ . ___ . _ . _. __ ·. __ . _ , . _ _ 0-6 

Hempstead gravel member of Manhasset formation: Fine dry sand ________ . ____ . ____ . ______ . _ 6-16 

Montauk till member of Manhasset formation: Rough stratum of cobbles with scarcely any 

sand between .. _.-.-_ ......... -.- ............................................ _. __ . ________ 16-22 

Herod gravel member of Manhasset formation: 

White building sand; very compact..:. __ .. __ .. __ ... _ .. __ .. _. ______ . ___________________ 22-40 

White loose dry sand ....................................................... _ ...... ___ 40-50 

Jacob sand: Yellow dry clay .......................... -..... -........ -. -- ............... _ _ _ 50-71 

Gardiners clay: Blue clay, containing some water ... _ .. _ ....... : .. _. __ ._. __ . _______ . _______ 71-91 

The record of n. well on West Neck also suggests the Jacob: 

629. Record of Mrs. M. H. Clots's well, West Neck. 

Feet. 

Wisconsin: Surface loam ................................ -........................... _.____ 0-10 

Montauk till member of Manhasset formation: Hardpan with graveL .. __ . ___ .. ______________ 10-25 

Herod gravel member of Manhasset formation and Jacob sand: Fine brown sand; a little clay.. 25-85 

Gardiners clay: Blue clay ......... -.......... -- .. --.- .... -..... -.... --.- ................ __ . 85-93 

Jameco(?) gravel: Brown gravelly sand; water bearing ...... __ ._ .. __ ... __ ._ .. _ .. __ . _____ -.-_ 93-97 

AGE. 

The Jacob sand is a transitional deposit between the Gardi.ners clay (here considered as 

representing the Yarn1outh interglacial stage) and the Herod gravel member of the Manhasset 

for1nation (considered as representing a part of the Illinoian glacial stage), but is regarded as 

belonging to the Illinoian stage. There is reason to believe that the_change·in deposition, as 

was pointed out in the discussion of the source of material (p. 107), was caused by the advent 

of glacial silts brought down from the north during the advance of the Montauk ice, but long 

before it invaded the region under discussion. The character of its· fossils_ seems to indicate 

that the climate at the time of its deposition did not materially differ from that existing during 

the accmnulation of the Gm·diners clay. 

The best loc~~lity for fossils is near the south end of the cliffs on the east side of Gardiners 

Island and south of the point at the south end of Tobacco Lot Bay. Fossils from a 4-foot bed 

of sand and fine gravel (Jacob) at this point were described as ·early as 1867 by Sanderson 

Sn1ith/ who gave a list of 25 species, all of which except one or two inhabit the waters south of 

- Cape Cod at the present tin1e. The shells, however, had a 1nore northern aspect than those of 

the species now ,inhabiting these waters. The species are as follows: 

Small coral . 

'l'ornatella punctostriata Adams. 

Bulht canaliculata Gould. 

Fusus decemcostatus Say. 

Purpura lapillus Lam. 

Nassa trivittata Say. 

Nassa vibex Say. 

Columbella lunata Sowerby. 

Chemnitzia interrupta Stimpson. 

Crepidula unguiformis Lam. 

Crepidula fornicata Lam. 

Natica duplicata Say. 

Natica heros or triseriata'? 

Area transversa Say. 

Area pexata Say? 

Ostrea borealis Lam. 

Pecten islandicus Chemn. 

Pecten:m,agellanicus Lam. 

Cardita borealis Conrad . 

Astarte sulcata Fleming . 

Lucina: radula Gould? 

Venus mercenaria Linn. 

Mactra laterales Say. 

Mya arenaria Linn. 

Balanus fragment. 

1 Annals New York Lyceum Nat. Hist., vol. 8, lSGi, pp. 149-151. 
114 GEOLOGY OF LOONG ISLAND • 

. A collectwn made by Veatch from sandy .clays and sands at the same point and examined 

by Dall afforded the following species: 

Chrypodomus pygmoous Gould. 

Chrypodomus decemcostatus Say. 

Natica (Lunatia) heros, Say. 

Pecten magellanicus Gmelin. 

Astarte elliptica Brown. 

Thracia conradi Couthuoy. 

Cyprina islandica Gmelin. 

Fossil fragments have also been fo>Jnd in the Jacob sand on Robins Island.-- (See fig. 

98, p. 110.) 

The views of Sanderson Smith as to the northern aspect of the forms were corroborated 

by Dall, who says.: "The material appears to be practically identical from both localities [on 

Gardiners Island] and to represent the fauna now exi~ting in the Gulf of Maine or on the coast 

north of Cape Cod, a little c~lder water being indicated than is now found soutli of the cape." 

The extensive fauna from the same horizon at Sankaty Head, Nantucket, likewise points 

to temperatures no colder than those of northern New England. 1 As the accumulation of ice 

for the next invasion had begun, however, the beds must be classed with the Illinoian rather 

than with the Yarmouth stage. 

MANHASSET FORMATION. 

NAME. 

Althou.gh the body of the deposits succeeding the Jacob sand may be supdivided into three 

distinct units, there are places, even in the best of cliff exposures, where the middle division is 

absent and the upper and lower beds, consisting of gravels of similar characteristics, unite to 

form a single unit. The combined beds give rise to the broad plateau stretching between the 

· northern moraine and the north coast and projecting through the outwash plain here and there 

south of the outer moraine. Because the middle bed is locally absent, and because the deposits 

constitute a topographic unit and in the absence of cliff and other sections it is in places difficult to recognize·the component members, it is necessary for their proper discussion to have a 

general term for the deposits as a whole. The term Manhasset is here used as a collective name 

for the beds referred to, being taken from Manhasset Neck, along the shores of which, in the 

immense gravel pits on the Hempstead Harbor side,' are to be seen exposures of these beds n1ore 

than 100 feet in height. The name was first applied by J. B. Woodworth;2 who described and 

mapped in detail the deposits in a part of the w~st end of the island. 

Veatch, in his report on water resources, substituted the term Tisbury for Manhasset, on 

the supposition that the beds were the equivalent of Woodworth's Tisbury beds of Marthas 

Vineyard, 3 which consist of stratified clays and clayey sands with some bowlders suggesting till 

outcropping along the nqrth shore. The horizontality of these beds on Marthas Vineyard is 

emphasized by W ood:worth, who says: "Their n1arked horizontality is strongly contrasted with 

the dislocated attitude of the beds ill the outcrops of the older folded series which appear at intervals along the shore." Horizontality was in fact, according to information furnished to the 

writer by Prof. Woodworth, the principal criterion of recognition. Inasmuch as the beds of the 

lower part of the Manhasset formation on Long Island, as well as the corresponding beds on 

Marthas Vineyard (included by Woodworth in his Sankaty), are strongly folde.d (see Pl. XIX, 

A), it is evident that the term Tisbury as originally used was intended to cover only the undisturbed beds laid down subsequent to the epoch of folding due to the Montauk ice. In other 

words, it was probably used for the beds here described as the Hemp.stead gravel member of 

the Manhasset. formation, although this correlation is only approximate. For these reasons it 

seems b~st to adopt the term (Manhasset) originally applied to the beds on Long Island rather 

than use t}w Marthas Vineyard term in a way apparently not intended by the geologist who prop~sed it. The relations of the Marthas Vineyard and Long Island terms are approximately as 

follows: 

1 Desor, E., and Cabot, E. C., Quart. Jour. Geol. Soc. London, vol. 5, 1849, pp. 340-344. Verrill, A. E., Am. Jour. Sci., 3d ser., vol. 10, 1875, 

pp. 364-375. Cushman, J. A., Am. Geologist, vol. 34, 1904, pp. 100-109. 

2 Bull. New York State Mus. Nat. Hist. No. 48, 1901, map. 

a Seventeenth Ann. Rept. U.S. Geol. Survey, pt. 1, 1896, p. 977. 

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U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 82 PLATE X IX 

A. FOLDED BEDS OF MANHASSET FORMATION NEAR TOM POINT, 

PORT WASHINGTON. 

B. BANDED MONTAUK TILL MEMBER OF MANHASSET FORMATION 

NEAR FRI ARS HEAD . 
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MANHASSET FORMATION. 115 

Long Island (this report). Marthas Vineyard (Woodworth's 

section). 

~ Hempstead gravel member. Tisbury beds. e 

0 

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"'o Montauk till member. Gay Head. ~:0 

~ Herod gravel member. ~ "' 

Sankaty beds. 

Jacob sand. 

Gardiners clay. I Not exposed. 

SUBDIVISIONS. 

The Manhasset forn1ation may be described as a ser~es of glacial sands and gravels, 150 to 

250 feet thick, having a middle member in which the sands and gravels are locally replaced by 

till. Where the middle member is well developed it is represented by a bed of till 40 to 60 feet . 

or n10re thick, the overlying and underlying beds being reduced to thicknesses of 50 to 75 feet 

each. The central till is not everywhere well developed, however, being in places, as ill the 

gravel pits on the west side of Hempstead Harbor·, reduced to a bowlder bed only a few feet 

thick. In a few places it disappears entirely, grading laterally into coarse stra~ified gravels, 

and in such places the entire formation consists of ·sands and gravels, marked, however, by 

slightly coarser 1naterials at the till horizon. 

Although the till is locally absent, it is on the whole a persistent and easily recognized 

n1en1ber throughout Long Island and in fact along the New England coast as far north as 

Maine, separating the two gravels into a lower bed here called Herod gravel member and an 

upper bed for which the name Hempstead gravel member is here introduced. The till it.self 

is here called the Montauk·till member . 

GENERAL DISTRIBUTION. 

The character, relations, and distribution of the three subdivisions of the Manhasset formation are considered in detail under their separate heads, only the distribution of the formation 

as a whole being here discussed. 

The Manhasset formation constitutes by far the larger par~ of the beds found above sea level 

on Long Island, forn1ing most of the drift hills at the west end of the island and the plateau 

that borders the north shore from East River to Port Jefferson and extends southward beneath 

the moraines toward the south shore, along which it rises above the outwash plains at numerous points. East of Port Jefferson the Manhasset forms the base on which ·the n10raines rest, 

as well as the plateaus of Robins, Shelter, Plum, Fishers, and Gardiners islands and of the South 

Fluke . OCCURRENCE NOR'J'H Qj.' THJ<~ HARBOR HILL MORAINE. 

Western Long Island.-West of Little N eel): Bay, which lies just east of Flushing, the 

M.anhasset formation is not s·een in any considerable amount, what there is of it being buried 

beneath the general till sheet. the Wisconsin moraines. and the later Wisconsin strat,ified gravels. 

These deposits have so obscured the :Manhasset topography that the plateau character, which 

is very pronounced farther east, is not conspicuous .. 

Great and Manhasset necks, North Hempstead.~On Great Neck, east of Little Neck Bay, 

the plateau character is notably pronounced, large stretches of nearly level flats standing 

between 100 and 120 feet above sea level from the railroad northward (Pl. IV, p. 30). Manhasset Neck shows the plateau character still better, the upper surface being here about 180 

feet above sea level from the moraine northward to a point beyond Port Washington village, 

where it slopes rather abruptly down to the 100-footlevel, at which there is another extensive 

plateau stretching toward Prospect Point . 

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116 GEOLOGY OF LONG ISLAND. 

Hempstead Harbor to Oyster Bay.-The Manhasset formation is best developed in the 

region between Hempstead Harbor and Oyster Bay, where it forms a belt nearly 7 n1iles wide 

between Harbor Hill moraine and the coast. , The surface seems to have a normal elevation of 

180 to. 200 feet, although rising somewhat higher near the moraine. South of Glenwood Landing, on Hempstead Harbor, is a local terrace of gravel at the 100-foot. elevation, separated as 

usual by a fairly abrupt slope from the higher Manhasset level (Pl. IV). The equivalent of this 

terrace is traceable around the coast from the vicinity of Red Spring Point to Oyster Bay 

(figs. 7 and 8, pp. 30 and 31). . 

· Oyster Bay to Miller Place.-From Oyster Bay to Northport the continuity of the 1\tJ:anhasset 

format1.on is broken by numerous bays and harbors and by deep pre-Wisconsin stream valleys, 

and the differentiation of the high and low deposits is more difficult, the one class grading 

almost insensibly into the other. Lloyd, West, and Eaton necks, however, belong in the main 

.to the lower or 100-foot terrace, and Great and Little necks and the deposits stretching south-

·ward to the moraine belong to the 160 to 200 foot level. East of Northport to the point where 

. the Manhasset disappears beneath the moraine near Miller Place, a strip a mile or two in width 

along the shore belongs to the 100-foot level, and the rest, extending back to the moraine, 

belongs to the higher Manhasset. 

OCCURRENCE BETWEEN THE HARBOR HILL AND RONKONKOMA MORAINES. 

Roslyn region.-Between the Harbor Hill moraine at Roslyn and the Ronkonkon1a moraine 

south of ·Albertson station is a stretch of country of puzzling contour. On the map. it appears 

as a fairly level plain suggesting an outwash accumulation, but on the ground there are many 

irregularities. Here .and there over the plain hills and ridges rise 10 to 15 feet or more above 

the general level, their tops generally being flat and standing at acc.ordant levels. Such a 

topography might arise from deposition around ice blocks or might represent projecting masses 

of the Manhasset formation, but in the absence of adequate. sections it is impossible to determine 

which origin is more probable., In favor of the second suggestion, however, it may be said 

that the Manhasset undoubtedly extend~ beneath the moraines and is likely to come to the 

surface at almost any point. The altitude of the flat-topped elevations is accordant with that 

of the Manhasset level north of the moraine. 

Huntington region.-In the region south of ·Huntington station (Fairground on the map) 

are many well-developed· kettle valleys, the result of the melting of ice messes lying in. the 

valleys of an older and now buried topography. The Manhasset formation, although not 

exposed, can not be far beneath the surface. 

Smithtown region.-A glance at the topographic map (Pl. II, in pocket) shows the welldeveloped branching drainage system of Nissequogue River. An esker three-fourths of a 

mile northeast of Smithtown extending to the bottom of the present valley indicates the Vineyard age of the erosion features, and an exan1ination of the materials exposed in the several 

valleys shows nothing but deposits of the Manhasset type. It seen1s clear that at this particular 

point practically all the deposits between th~ moraines are 1\tJ:anhasset. 

Port Jefferson region.-In going southward from Port Jefferson station one passes 0~ er an 

exceedingly flat ·plain of outwash from Wisconsin ice, which continues with hardly' a perceptible irregularity for 2 miles or more. At this distance, however, irregularities begin to appear. 

l(ettle depressions pit the surface and low swells rise above it, as near Terryville. A little 

farther on the depressions take the ·form of broad, shallow, well-defined yet streamless valleys 

with branches on either side, the intervening ridges constituting the elevations. In fact, the 

topography has undergone a change from one clue to deposition to one clue largely to erosion. 

The valleys lead southward toward the sea but are cut off by the southern moraine, which rises 

~hove the plains, completely blocking the channels. The erosion is clearly assignable to the 

· Yineyarcl interval an~ there is every reason to regard the deposits as Manhasset. 

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U S GEOLOGICAL SURVEY PROFESSIONAL PAPER 82 PLATE X X 

TOPOGRAPHIC FEATURES NEAR MIDDLE ISLAND, LONG ISLAND, N.Y."' 

Scale az~oo 1 ~ o l. 2 Miles 9=~3=~~~~~~~======~ 

Contour interval 20 £eet. Dal:lo/1/ is f1U!,QA, se-a level. 

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MANHASSET FORMATION. 117 

Rocky Point region.-In the region east of Port Jefferson conditions seem to be similar to 

those in the vicinity of Iluntington. Just south of Rocky Point village are unusually good 

examples of branching kettles resulting fron1 the .melting of ice masses in the valleys of the 

unc~erlying :Manhasset surface. Plate XX shows one of these kettles as represented on the 

topographic map. A mile or two farther south the valleys, like those south of Port Jefferson, 

are evidently cut in the Manhasset formation. · 

lVading River region.-The conditions in the vicinity of Wading River are much the same 

as at Rocky Point village, except that the branching kettles and surface valleys in the Manhasset are still more conspicuous. Although the :Manhasset controls the topography everywhere except within a short distance of the moraine, there is nevertheless here as elsewhere 

more or less Wisconsin drift, which locally complicates and even obliterates the Manhasset 

surface . 

Middle Island region.-On the geologic map (Pl. I, in pocket) a considerable region, 

extending from Coram on the west to the headwaters of Peconic River on the east and from 

the vicinity of Long Pond on the north to the Ronkonkoma moraine on the south, is represented 

as till. Throughout this region the topography is characteristic of erosion. Several deep and 

fairly sharp valleys with branching and rebranching tributaries, all manifestly cut in a preWisconsin surface, leaQ. southward toward the sea. Plate L"'\:: shows what is probably.the best 

example of a kettle valley on Long Island, the depre~sion being nearly 4 miles in total length 

and having not less ~han fiv~ major branches (one of these rebranching) as well as many minor 

ones not shown on the map. Though mantled with a thin coating of later drift, the body of 

the deposit of this region belongs to the Manhasset formation~ . 

Fresh Pond Landing region.-The moraine is very weakly developed near Fresh Pond 

Landing, the Manhasset capped by thin outwash stretching inward from the coast. ·It is cut 

by the northward-leading channel shown in Plate IX, B (p. 42), the continuation of which can be 

traced several miles toward the south by depression channels and kettles . 

Riverhead region.-The :region between Riverhead and the moraine on the north seems to 

consist 1nainly of the Manhasset formation, which was deeply dissected by stream erosion and 

later covered by a thin mantle of outwash along the moraine and by thinner and moreo irregular 

outwash deposits elsewhere. The old drainage topography is marked .by the original channels, 

by kettle valleys, or by chains of isolated kettles. The region between Riverhead and Baiting 

Hollow probably affords the best illustration on the island of the last-named feature (Pl. IX, 0) . 

So1ne of the old valleys are almost as well and as ·definitely marked by the succession of kettles 

as if the channels were continuous. . 

Mattituck region.-The region about Mattituck presents another example of deeply dissected l\1anhasset deposits overlain by a superficial coating of late drift. This feature is best 

brought out by Mattituck Inlet (Pl. XI, 0, p. 52), which represents an almost unaltered drainage 

systen1 of the Manhasset .. This channel originally led southward, but is now obstructed by 

Wisconsin drift and forced to en1pty northward into Long Island Sound through what was 

originally one of its headwater ch!lnnels. 

North shore from Mattituck Inlet to Orient Point.-Essentially the same conditions as at the 

localities farther west exist east of Mattituck Inlet. The Manhasset, here as elsewhere characterized by Vineyard erosion valleys, constitutes the main part of the deposits, the outwash 

from the Wisconsin ice being weakly developed and confined mainly to the vicinity of the 

mora me. 

Peninsulas of the North Fluke and Shelter Island.-South of the line along which the Manhasset of the Nor~h FJuke proper and its mantle of outwash sinks beneath the sea lie a series 

of islands and peninsulas, the latter ahnost disconnected from the mainland, which rise abruptly 

from sea level-to heights of 60 to 160 feet. From west to east these are Robins Island, Nassau 

Point, Great Hog Neck, and Shelter Island, the whole forming a belt exactly parallel with the 

North Fluke. Eac~ of the peninsulas shows clear evidence of pre-Wisconsin erosion and equally ~ 
118 GEOLOGY OF ,LONG ISLAND. 

·clear evidence of, in the inain, post-Gardiners deposition,· and although the deposits are not a 

unit with those underlying the North Fluke proper, they must be considered as belonging to 

the same general series-the Manhasset formation. 

Peninsulas of the South Fluke.~Stretchin.g northward from the axis of the South Fluke,· 

well north of the outer moraine, are a number of peninsulas similar to the peninsulas and islands 

associated with the North Fluke and likewise falling into a well-marked east-west alignment. 

Their exposures show them to be composed of Manhasset material, except for the Gardiners 

clay near sea level. Unlike the penmsulas of the North Fluke, however, they do not seem to 

belong to a series distinct from that of the fluke proper, but rather to represent remnants of a 

plateau or terrace similar to the north-shore plateau west of Port Jefferson. 

OCCURRENCE SOUTH OF THE RONKONKOMA MORAINE. 

Hempstead region.-:-East of Jamaica and contin.uing across the to\vn of Hempstead to the 

Oyster Bay line, the broad plains that stretch southward fron1 the Ronkonkoma moraine, 

although in their broader aspects having the appearance of outwash deposits from Wisconsin 

ice, present many minor features suggesting that an older topograpp.y may project here and there 

through the superficial mantle of outwash. Except at Rockaway Ridge, however, the topography ia not sufficiently definite nor the exposures of the older beds sufficiently clear to identify 

them with certainty, but there is little doubt that the Manhasset constitutes the greater bulk 

of the depo~its beneath the Wisconsin gravels that form the surface of the outwash phiin. The 

de~elopment of the Manhasset deposits immediately north of the moraine and their observed 

occurrence beneath the northernmost of the morainal ridges would make it almost certain,· · :~­

even if there was no other evidence, that the Manhasset formation extends south,~ard beyond 

the moraines in strongly developed form. -

Rockaway Ridge (see Pl. II, in pocket) affords a good example of the extramorainal1\1anhasset material, standing many feet above the surrounding outwash plains from the Wisconsin 

ice and eXhibiting an erosion surface evidently antedating the deposition of the surrounding 

gravels. The character and relations of these deposits ar~ considered in more detail on page 127. 

Bethpage region and Half Hollow Hills.-Two well-developed terraces of gravels of the 

Manhasset type occur just south of the West or Mannetto Hills (Pl. III, p. 28), and a single but 

higher and more extensive terrace is present in the Half Hollow Hills. These terraces are correlated with the Manhasset formation. 

Wyandanch to Central Islip.-From Wyandanch, near the south end of the I-Ialf Hollow 

Hills, eastward along the railroad to Brentwood there is very little evidence by which to differentiate the Manhasset from the outwash, b'ut from Brentwood to Central Islip station features 

suggesting an older surface are more numerous', making it clear that the 1\1anhasset is at or near 

the surface and is beginning to exert a decided influence upon the topography. . 

Central Islip to Yaphank.-The Manhasset becomes an important factor in the topography 

immediately east of Central Islip but is soon interrupted by the broad outwash channel leading 

south from the Smithtown region north of the outer (Ronkonkoma) moraine. Near Ronkonkoma its control of the topography again becomes apparent, and similar conditions continue 

eastward to the second great valley at Yaphank. Along the base of the moraine and stretching 

southward to the railroad the Manhasset is recognized by irregularities in the shape of elevations 

rising above the outwash or by dendritic .drainage channels, now streamless, quite different from 

the· channels of the outwash proper. Throughout this stretch, also, the Manhasset is an important factor of the topography, especially near the coast, the _outwash, except near the moraine, 

having only a subordinate influence.. However, the relief of the old surface was so s1ight, the 

materials are so similar in composition, and the general slope is so near that of the Wisconsin _ 

deposits that, although it is possible to say that two surfaces of widely different ages are present, 

it is impracticable to differentiate between them with sufficient accuracy for mapping. 

Yaphank to Shinnecock Oanal.-Conditions similar to those just described exist in the 

region between Yaphank and Shinnecock Canal, the Manhasset apparently being even better 

represented. Along the coast, and especially on the peninsulas, much of the topography is 

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U . S GEOLOGICAL SURVEY PROFESSI ON AL PA PER 8 2 P L ATE X XI 

A. OUTWASH TOPOGRAPHY NEAR SOUTHAMPTON. B. MANHASSET AND OUTWASH TOPOGRAPHY 

NF.AR AMAGANSETT LONG ISLAND, NEW YORK 

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S c ale sz;o o 2 Miles t 0 1 

Contour in:te:rval 2 0 £e et . .Dat:urn is m .. ea:n s ea lev el. 

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MANHASSET FORMATION. 119 

clearly of a type characteristic of erosion rather than of deposition and belongs to the :Manhasset 

rather than to the ·Wisconsin outwash. The necks southwest of the canal and southwest of 

:Moriches are exa1nples of accumulations that are apparently almost entirely of l\ianhasset age. 

Bridgehampton region.-Eastward from Shinnecock Bay to Meco~ Bay the l\ianhasset is 

not definitely recognized, although i11dications are not entirely lacking that the deposits are in 

places near the surface. Between Mecox Bay and Bridgehampton the Manhasset again controls the topography, although locally covered with a considerable thickness of outwash which 

has entirely obscured the older drainage. In several places, however, the older drainage lines 

are now indicated by kettle channels or chains similar to those occurring at many points between 

the moraines near IIuntington, Rocky Point, Middle Island, Wading River, Riverhead, and 

elsewhere. One of these channels is shown in Plate IX, A (p. 42). 

Amagansett region.-East of Bridgehampton the l\ianhasset is again absent from the surface 

as far as E.asthampton, but from Easthampton eastward through Amagansett as far as Promised 

Land it shows at many points. The topography in this region is very irregular, almost no outwash being present. ·This is well brought :out by Plate L~I, B, in which the extramoraind 

topography is in notable contrast to the mo.re purely outwash topography shown in A of the . 

smne plate. DEPOSITS PBNETRA1'ED BY WELLS. 

The Manhasset is- encountered in probably more than three-fourths of the wells on Long 

Island and is clearly represented in a large number of well records. In many records it is even 

possible to recognize the three subdivisions, as brought out in the tables and records given in 

the separate discussions of the Herod, Montauk, and Hempstead members. Data regarding a 

number of additional wells, in which the subdivisions have not been differentiated, are given in 

the following table: 

No.a Locality. 

35 Brooklyn ............ . 

38 Do ............... . 

135 East Now York ...... . 

187 :Far Rockaway ....... . 188 Do ............... . 191 Do ............... . 193 Threemilo Mill ....... . 195 Aqueduct ............ . 199 Jamaica South ....... . 201 Do ............... . 202 Do ............... . 203 Do .............. .. 204 Springfield ........... . 205 Do .............. .. 206 Do ............... . 212 Jamaica ............. .. 24L Whitestone .......... . 285 Valley Stream ........ . 287 Do ............... . 291 Springfield ........... . 295 Do ............... . 374 Long Beach .......... . 

Undifferentiated Manhasset formation in the wells of Long Island. 

Owner or place. 

Forest Street and Evergreen Avenue. 

Bartlett Street and Flushing 

Avenue. 

New Lots Road and Foi.mtain A venue. James Caffery .............. . B. L. Carroll ............... . Queens County Water Co .. . '1'. H. Chapman ............ . Shetucket pumping station .. Oconee pumping station ... . Jamcco pumping station ... . Brooklyn test well No. 1. .. . Brooklyn test well No.2 ... . Brooklyn test well No.3 ... . Brooklyn test well No.4 ... . Springfield pumping station. 

Brooklyn test well No. 1i. .. Hailroad wells ............. . Brooklyn test well No. 19 ... . Brooklyn test well No. 25 ... . Brooklyn test well No. 12 ... . Brooklyn test well No. 10 ... . Poorhouse ................. . 

Depth of 

material. 

Feet. 23-105 

b 6-45 

4-93 

0-42 

0-45 

0-60 

b 0-140 

90-135 

b9-56 

18-86 

54-89 

19-83 

45-86 

27-72 

20-65 

20-95 

15-60 

18-72 

15-62 

30-98 

40-80 

0-75 

Character of materials. Correlation with name used 

in original records. 

Yellow gravel and sand................. Wisconsin and Tisbury. 

Sand and gravel......................... Do. 

Yellowish sand, granitic gravel, and thin Do. 

gray clays. Yello\vish gravel. ....................... · Tisbury. Fine to coarse sand and gravel.......... Do. 

Light-yellowish sand and gravel......... Do. 

Sand, quicksand, and clay ............... Wisconsin and Tisbury. Fine to coarse gray to brownish sand ..... '!.'is bury. Reddish-yellow sand.................... W~sconsin and Tisbury. Yellow to gray sand with pebbles ........ 'I.'isbnry. Gray to yellow sand and gravel.......... Do. 

Yellowish to gray sand and gravel....... Do. 

Fine yellowish sand..................... Do. 

Brownish-yellow and gray sand......... Do. . .... do.................................. Do. . .... do.................................. Do. 

White sand............................. Do. 

Gray to yellowish sands and gravel...... Do. 

Fine yellowish sand ........ :............ Do. 

Yellow, gray, and reddish sands......... Do. 

Yellow and gray sanos.................. Do. 

Yellow to gray, sometimes clayey sands. . Do. 

a Numbers refer to well records in Prof. Paper U. S. Gcol. Survey ~o. 44. bIn part. 

SPECIAT" J<'EA'J'URI~S 0.1~ 1'HE DIS'l'RlBU'l'ION OJ<' 1'HE l\IANHASSE'l' PORl\IATION. 

The Manhasset fonnation as a whol_e displays three belts of more prominent development, 

which may be called the north-shore belt, the Middle Island belt, and the South_ Fluke be]t. 

North:..shore belt.-Of the three belts the north-shore belt· alone is continuous throughout 

the island, being represented by the broad Manhasset terraces from New York to Port Jefferson 

and by the bluff deposits frmn Port Jefferson east to Orient Point. The accumulations are 

thickest at the Sound shore and become rapidly thinner toward the south, being at a distinctly 

lower leYel south of the IIarbor Hill 1noraine. The slope -is well shown in the region east of 
120 GEOLOGY OF LONG ISLAND. 

Wading River (fig. 107), where the outwash is relatively thin, the Manhasset surface declining 

from an altitude of about 120 feet along the coast nearly to sea level along Peconic River, which 

appears to occupy a fosse between the plain· and the northern face of the Middle Island belt of 

..c 

en 

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11.1 

Ul 

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the Manhasset. Just east 

of Riverhead the beds slope 

from an elevation of about 

80 feet on the Sound to sea 

level on the shore of Peconic 

Bay, 4 miles to the south. 

Still farther east both the 

thickness of the Manhasset 

along the north coast and 

its extent toward the south 

decrease until near Orient 

Point the formation has a 

maximum elevation of only 

about 30 feet and a width 

of less than a mile . 

.o Middle Island belt.-The 

§ Middle Island belt is most ~ 

b.O 

~ 

distinct at its east end, 

where it is represented on 

'0 Shelter Island. To the west ~ 

E it is represented by Great 

~ Hog Neck, Nassau Point, 

~ and Robins Island, by the 1 thick deposits bordering Peconic River on the south g 

:g from Riverhead to South 

~ Manor, and by the high 

~ deposits between the mol raines at and near Middle ~ ~ Island. West of this region 

~ the continuation of the Mid-

~ dle Island belt is obscured 

for many miles, but there 

are topographic indications 

pointing to a Manhasset 

scarp similar to that of the 

north-shore belt but mainly 

buried, extending westward 

along the line of the Ronkonkoma moraine to the 

Half Hollow Hills, which belong to this belt. The next 

representatives of the belt 

appear to be the ]_3ethpage 

terraces, lying southwest of 

these hills and possibly indicating a swing of the belt 

in that direction. Rockaway Ridge, the last Manhasset remnant in this belt, agrees in trend 

with the southwesterly bearing assumed between the Half Hollow Hills and the Bethpage terraces. Possibly Gardiners Island, at the opposite end of Long Island, represents the easterly 

continuation of the same belt. 

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MANHASSET FORMATION . 121 

The Middle Island belt shows, where not obscured by later deposits, the same northwardfacing scarp as the north-shore belt, but the southward slope is not so conspicuous. The drainage, 

however, seems to have commonly flowed toward the south, indicating a general slope in that 

direction. The formation maintains its thickness on the whole more persistently than in the 

north-shore belt, although show:i,ng great local variations. At Rockaway Ridge the upper · 

surface stands about 30 feet above sea level; at Bethpage, 180 feet; in the Half I-Iollow Hals, 

240 feet; at Middle Island, ~40 feet; south of Peconic River, 100 feet; on Robins Island, 60 feet; 

on Nassau Point, 60 feet; on Great I-Iog Neck, 40 feet, and on Shelter Island, 100 feet·or more . 

The subaerial erosion is fully as far advanced as in the north-shore belt, and the features due 

to marine erosion are even more conspicuous, although the erosive action was probably less. 

South Fl11.ke belt.-The South Fluke belt of ·the Manhasset forn1ation is most readily traced 

by beginning at the east. The great mass of the deposits beneath the thin coating of late till 

on the Montauk Peninsula are Manhasset and constitute the east end of the belt. Interrupted 

'by the connecting beach and dunes at Promised Land, the belt is continued toward the west 

by the broad Manhasset areas of the two great necks east of the town of Sag liarbor, by Ilog 

Neck north of this town, and by the high hills between N oyack, Little Peconic, and Great Peconic 

bays and the moraine, as well as by the Manhasset remnants seen south of the moraine. The 

South Fluke belt seems to join the Middle Island belt in the vicinity of Riverhead. The maximum elevation of the Manhasset at Montauk is about 150 feet; in the region between Promised Land and Sag Harbor and on the shores of Little Peconic and Great Peconic bays it is 120 

:feet. From these altitudes the Manhasset appears to slope southwa:r;d, passing beneath the 

moraine and a part of the outwash, and seems to have originally reached sea level a little south 

of the present coasts, which are now commonly lined with bluffs rising a few feet above tide 

level. 

In figure 107 a number of profile sections bring out the relations of the :Manhasset forillation in the three belts described above. 

HEROD GRAVEL MEMBER. 

NAME. 

The tern1 Ilerod gravel member is applied to the sand and gravel beds constituting the 

lower third of the Manhasset formation, or that part lying below the middle or Montauk till 

member. The na1ne is taken from Herod Point, near Wading River, on the north shore of Long 

Island, where the gravel is well exposed. 

CHARACTER. 

The Ilerod gravel member varies greatly from point to point, in some places being prevailingly sandy and in others consisting largely of gravel. The change in character is abrupt 

in many places, both vertically and horizontally, sand beds giving place to gravel or gravel to 

sand within a distance of a few yards. In general sand is more likely to prevail near the contact with the underlying Jacob sand, and gravel is more likely to become abundant as the 

horizon of the overlying Montauk till member is approached. In places beds of sand 10, 20, or 

even 30 feet thick, containing scarcely a pebble, are to be seen, but in its more normal phases the 

deposit consists of an alternation of thin layers of sand and gravel, the whole having a gravelly 

aspect. The pebbles are commonly small, those half a~ inch to 2 inches in size predominating, 

but in the upper part of the member they are considerably larger, 3 to 4 and even 6 inch 

pebbles being common. The character .of the pebbles differs greatly in the different parts of 

the island. 

lVestern Long Islarul.-Near the west end of the island a large percentage of quartz pebbles is present, this material in fact predominating over the granites. The greater part of the 

qu~rtz pebbles are stained yellow by oxide of iron, giving rise to the term "yellow gravels," by 

which they were formerly known and on the bas.is of which they have been by some writers 

correlated with the "yellow gravels" of New Jersey. The "yellow gravelsn of New Jersey 

are in real1ty a n1uch older deposit, corresponding with the Mannetto or still older beds. In 
122 , GEOLOGY OF LONG ISLAND. 

them the basic granite pebbles are gone, those of the acidic type are deeply rotted, and even the 

cherts and some of the quartz pebbles have been weathered and weakened. In the Herod 

gravel member, on the other hand, the granites are as a rule not deeply weathered and the 

quartz and chert pebbles are. quite fresh. 

Next to the quartz the granite or gneissic pebbles are most abundant, both basic and 

acidic types being represented. Many of the basic or biotitic pebbles are more or less weathered 

and rotten, although perfectly fresh specimens are not uncommon. It is believed that freshn·ess is the normal condition, the alteration of the weathered pebbles having been well advanced 

before they were incorporated in the deposit. The acidic muscovite"'-orthoclase varieties seem 

to be but little weathered. 

In addition to the quartz and granite pebbles there are numerous concretionary fragments consisting mainly of quartz grains cemented by reddish (hematitic) oxide of iron and 

ranging fr01n a fraction of an inch to a foot in length. Limonite concretions occur here and 

there in pla~e. Silicified fossils and cherts,. although forming quantitatively' a very unimpor-· 

tant part of the deposits, are nevertheless sufficiently common to be found by careful search in 

almost any exposure in this part of the island. It is interesting to note that on the whole the 

quartz pebbles are rounded as much as, if not more than, those of the granite. 

The staining of the gravels is. in part primary and in part secondary. Many of the stained 

quartzes; for instance, occur in beds in which the surrounding pebbles are entireiy unstained, 

showing conclusively th~t their staining antedated their deposition in their present situation. 

On the other hand, the heds in many places have been discolored 

,,,~~~~~~~~~~~,,~~~~"~~~~~,,~' since their deposition. Locally the discoloration is limited to a '''' ''·' '' ,., '' ~ '' '' '' ''' ''' ,, ~'''"'''''''''"''''''''' ,,,, ll b h f bbl h t . th 6 . h . ''''''''''''''''" ''''"''-','''· sma unc o. pe es, per aps no more . an 1nc es In 

)jlf!j!f!l!f!j!j!j~r?f!f!!!\_IPif!lrrf!j!)!).!jfjf diameter in the aggregate, ·the staining material clearly coming 

li\l~lhli!t!l!l!l!!i\,1\llih!l!l!i\!il.l!l\1\i\dih! from an iron-bearing pebble in the center. In some places the. 

==-:--=-~ ~-=-::~..::.--=--=='=~==== streaks extend directly downward from the source of the staining 

~;j:.~~~ ~i==:~~~~-:..~~=3. solutions, which may be either a pebble or a lamina of sand rich __ ..:.-- - ~-- ----- ~ _..., in iron-bearing minerals. An interesting feature is shown in 

FIGURE lOS.-Diagram of vertical pseudo- figure 108, which illustrates what at first sight appeared to be a bedding in Herod gravel member. 

most puzzling case of vertical bedding. The vertical banding 

appeared to be as regular and perfect as in any normal bedding, and only close examination 

revealed it t~ be due simply to discoloration. 

The greatest amount of oxidation appears to have oecurred where some finer sand or clay 

served to collect the downward-percolating waters, which have stained and even partly cemented 

the immediately overlying beds. In places,. as in the gravel pits beneath the moraine on the 

east side of Roslyn, there appears to be a general staining of the section as a whole, the material 

being of the characteristic huff color. 

The bedding of the gravelly phases of the Herod member is normally horizontal, as shown 

in the sections in the b.ig gravel pits on Hempstead !-!arbor, but cross-bedding is not rare, especially in the upper part of the member. It is, however, generally of local occurrence ai).d of 

no great magnitude. The bedding in the sandy phases of the member is nearly everywhere 

horizontal, except where disturbed by subsequent folding, and much of the lamination is 

distinct and delieate. Ripple marks are present here and there. Internal unconformities 

due to contemporaneous erosion and deposition are not uncommon, although in the member as 

a whole they can not be said to be numerous .. 

A noticeable feature of the member as exposed near Far Rockaway, on the south shore, is 

the presence of numerous pebbles showing faceting by the wind. A large part of these lie at 

some distance below the surface and beneath other gravels, but they appear from the absence 

of subsequent rounding to be substantially in place. No faceting was observed on the pebbles 

in the Herod member of the north shore. 

Central and eastern. Long lsland.-East of Hempstead the character of the Herod member 

undergoes a gradual change. Quartz and concretionary fragments become less common and 

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MANHASSET FOR.MATION-HEROD GRAVEL MEMBER . 123 

are seen at relatively few points beyond the Cretaceous· and Mannetto remnants on Lloyd and 

Eaton necks, on the north coast, or east of the Manhetto and Half I-Iollow hills of I-Iuntington 

Township, in the interior of the island. Cherts an9, silicified fossils appear to be absent. Structurally there seem to be more irregularities as one goes eastward, cross-bedding being much more 

common and bowlder pockets not rare. The stained appearance is largely lost, the beds in 

general having a very fresh aspect. Acidic ·granites become relatively common, b1.1t basic 

granites are comparatively rare, although some trap fragments occur. In the relative amounts 

of sand and gravel there is no marked change, although there appears to be a tendency toward 

g1·eater fin~ness of material. Although it i~ difficult to make an accurate comparison of the 

I-Ierod member with the outwash gravels of the Wisconsin stage, because of the absence of 

good exposures of the latter, it is probably safe to say that in general they resemble one another 

·very .closely both in c~)]nposition and structure, and that in exposures where the relations are 

not shown it would be iinpossible to distinguish the two, a fact that adds much difficulty to the 

differentiation of the deposits south of the n1oraine. 

SOURCE OJ< MA'PERlAL . 

TVestern Long Island.-From the west end of Long Island eastward to the last exposure of 

Cretaceous and l\1annetto at Eaton Neck and Northport 'there is, as has been· pointed out, a 

pred01ninance of quartz in the Herod member as a whole, but beyond the limits of the extensive 

older beds the quartzose character disappears. It seems clear, therefore, that it is to the beds 

of these older deposits, either on the island itself or in adjacent ·parts of Long Island Sound, 

that one must look for the source of the materials. If any considerable quantities were brought 

from the Sound itself, it would be expected that characteristic materials would be found east 

of the Cretaceous and Mannetto land masses. No notable quantities of such materials, however, have been found. 

In the clayey parts of the Cretaceous the pebbles are usually white and entirely unstained, 

but in the sandy' and gravelly phases staining is very common. The staining in the Mannetto 

appeal'S to be universal. The stained pebbles of the Herod member may therefore be r~ferred 

with some confidence either to the Cretaceous or to the Mannetto gravel, and the white pebbles 

would be referred either to the clayey Cretaceous deposits or to young drift brought in from the 

north. The only clue to indicate which source afforded the white quartzes is the extent to which 

they are rounded, the Cretaceous pebbles being in general considerably more rounded than 

those from the Pleistocene. From this indication the Cretaceous seems to have been the 

principal source. The so-called concretionary fragments appear to represent both actual conm·etions and thin cemented layers from the Cretaceous sands. Such layers are very numerous 

and in places highly irregular, simulating true concretions: Some may come from the Mannetto 

gravel, but none have been observed in place in this formation. 

The granite pebbles appear to have been transported in the main from the Connecticut 

shore, the freshness of most of the material indicating derivation directly from the ledges. 

Some of the granites, however, seem to have been derived from ledges or from pebbles from 

older deposits in which weathering was already well advanced at the time of removal, although 

they were still sufficiently firm to permit their handling by ice or water. The relative scarcity 

of granite pebbles in the Herod member south of the moraine is attributed to the greater distance the materials were transported and the greater erosion they have undergone, whereby 

the smaller and more weathered pebbles were broken up and dissipated. The cherts and silicified fossils are evidently fron1 the metamorphic limestones on the n1ainland to the northwest. . 

. Oentral and eastern Long /sZand.-Although granitic pebbles are nearly everywhere abundant 

in thel-Ierod member,itison thewholen1oresandythan most glacial gravels. As has been shown, 

the Mannetto gravel was once a thick and extensive formation, stretching some distance into 

the region of the Sound, if not to the Connecticut shore. N otwith~tanding the great erosion to 

which this forn1ation has been subjected, it is not improbable that there were remnants of it 

beneath the Sound at the time of the I-Ierod deposition, and these 1nay have furnished some of 
124 GEOLOGY OF LONG ISLAND. 

the materials, although stained pebbles such as are found farther west are commonly lacking. 

Extensive areas of the Sound were also doubtless underlain by the Jameco gravel, which presumably furnished a large amount of material. To its derivation from these formations the 

Herod member probably owes its prevailing sandy character. The granite pebbles probably 

represent in part the reworked Jameco and in part fresh material brought in from the mainland. 

RELATION TO OTHER DEPOSITS. 

At the base, as elsewhere mentioned, the Herod gravel member merges by gradual transition into alternating layers of coarse and fine s~nds a'nd finally into the clayey Jacob sand 

(figs. 67, p. 97; 75 and 76, p. 99; and 98, p. 110), the only unconformities being those of overlap where the gravel reaches beyond the Jacob sand and abuts upon the Mannetto gravel or 

the Cretaceous deposits. . 

In many .-small exposures the Herod member appears to be overlain conformably by the 

Montauk till member (figs.109; and 167, p. 146), but in larger exposures, where several rods of 

the contact may be seen, an unconformity is almost invariably found. The unconformities range 

from shallow, almost unnoticeable depressions in the Herqd surface to deep and perhaps sharp 

·troughs, many of which cut entirely through the Herod into the underlying Jacob sand or 

Gardiners clay. 

The nature of the contact between the Herod member and the Montauk member is far 

from uniform. Where the overlying deposit is a true till the contact is in many places sharp 

and distinct and it may be of the so-called knife-edge type, the. transition from one member to 

the other taking place within less than a quarter of an inch. This is probably to be regarded 

as the characteristic contact. In places, however, there is a somewhat gradual transition.from 

the gravel into the till, as if the former had been reworked and incorporated with the latter. 

Where the Montauk is represented by its 

r -~f~~~ ::v~~:~::~h~;et~: ~e;:t ::!~:;. grading upward, although in places somewhat abruptly, into the coarser gravel of FIGURE 109.-Section near Quince Tree Landing, Montauk, showing till of the Montauk member. Here and there 

Montauk type resting on arched Herod gravel member. 

0 100 zoo Feet ~------~------~ 

the Montauk member is too poorly developed to be recognized and the Herod merges with the similar gravel of the Hempstead 

member to form a single thick gravel formation. 

At a few places the Montauk iGe seems to have planed and eroded the Herod member without 

leaving the usual deposit of till, and the Herod member is separated from the Hempstead member 

by an unconformity. One of these places is shown in fig~es 116 (p. 126) and 180 (p. 153). 

The ice in passing over broke up the stratification in the upper part of the lower sand and in 

connection with a subsequent oxidation or staining produced local phases strongly resembling 

soil zones. · 

STRUCTURE. 

In common with the underlying beds the Herod gravel member was affected by the disturbance produced by the overriding Montauk ice. There are, however, certain points of 

difference. Because of its loose, friable character the Herod tended to crumble and disintegrate rather than to resist and become warped under the ice pressure. Folding is therefore 

less common in the gravel than in the more resistant Gardiners clay and Jacob sand, and where 

it has occurred the folds are generally broad and open, as if the material had been lifted by 

deformation of the underlying clay. This deformation may have been due to pressure transmitted laterally or to unequal settling under the weight of the ice sheet. In places, however, 

either because it contained a higher percentage of cl~y or because it was frozen at the time, the 

gravel appears to have afforded more resistance to the ice than usual and was folded in much 

the same way as the underlying beds, although never forming the sharp pinnacle-like folds nor 

showing the minute crumpling eXhibited in many places by the clays. The character of the 

folding is brought out in more detail in the following discussion of the distribution of the 

grayel. 

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MANHASSET FORMATION-HEROD GRAVEL MEMBER, 125 

DISTRIBUTION. 

East River to Little Neck Bay.-Along the north shore west of Little Neck Bay the Montauk 

till member reaches down nearly or quite to sea level, the Herod gravel member where present 

lying mostly below that level. It is possible that the Herod member is not as thick here as 

farther east, owing .either to the earlier advance of the ice in· the west and the consequent 

early replacement of the Herod by the Montauk, or possibly to greater reduction, by erosion. 

Great and Manhasset necks, North Hempst'ead.-The most western locality at which the 

Herod gravel member appears in considerable amounts is on Great Neck;, where it forms the 

lower part of many of the bluff sections and extends below sea level. On Manhasset Neck the 

gravel is seen on the west and north shores (fig. 137, p. 135) b~t is best developed on the west 

side. A line of immense gravel pits cutting into the hills extends along the harbor, giving 

clear-cut sections of the Herod membe~ from its contact with the Montauk till member at an 

altitude of 7 5 to 100 feet down to the Jacob sand or the Cretaceous 

clay near sea level. The material here consists of a fairly regular 

alternation of sand and fine gravel throughout the whole of. the section . 

. Hempstead Harbor to Oyster Bay.-The Herod men1ber is well exposed in the gravel pits near Glenwood Landing, on the east side of . 

0 

IIempstead Harbor, where 40 to 50 feet of rather fine cros~-bedded FrGUREllO.-Sectiononthecoast 

gravel was seen. It seems to form a considerable part of the lower portion of the bluffs from Roslyn to the mouth of the harbor. From 

I-Iempstead Harbor to Oyster Bay the member is seen at 'few places 

along the shore, owing apparently to the extensive erosion hy the l\1onnorth of Fort Salonga. Montauk till member (a) banked 

against Herod gravel member 

(b) and overlain by Wisconsin 

till (c). 

tauk ice, bt1t it unquestionably occurs beneath the plateau stretching inland from the coast, 

probably embracing most of the materials from sea level to a height of 50 or 75 feet. At 

Rocky Point, 2 miles north of Oys.ter Bay, it is seen between the Gardiners clay and the l\1ontatlk till member but is here of slight thiclmess (fig. 65, p. 96). On both the west and east 

shores of Oyster Bay Harbor and at Coopers Bluff it appears to constitute the lower parts 

of the blnffs. 

Lloyd Neck to Northport.-As is usual where the Cretaceous is present above sea level, 

very little of the Herod n1ember is to be seen at Lloyd Neck, whatever Herod material may have 

been deposited around the Cretaceons masses having been removed by the Montauk ice or so 

disturbed as to be rendered unrecognizable. ·on West Neck, jnst south of Lloyd Neck, considerable Herod ~aterial is present and may be seen lying upon the Cretaceous clays (the 

Gardiners clay being absent) at one or more points along the shore of Cold Spring Harbor. 

Fron1 Halesite to Centerport on Great Neck the conditions are similar to those on· Lloyd Neck, 

no good exposnres of the IIerod member being seen. On the west side of Little Neck a short 

distance south of Little Neck Point folded sands 

of the Herod type were seen underlying what 

appears to be the l\1ontauk till member. On 

Eaton Neck, to the north, the conditions also 

resemble those on Lloyd Neck. In one se~­ FmURE 111.-Section half a mile east of Woodhull Landing, showing 

strongly arched beds of Herod gravel member. tion, however, folded beds of the Herod gravel 

n1ember were observed between the Gardiners 

clay and the Montauk tillme1nber (fig. 66, p. 97). Fairly good exposures of the gravel, consisting of rather fine, even-bedded sand with wavy ripples, were found in the lower part of the bluffs 

on the east side of Northport Harbor, north of the town. 

Northport to Port Jefferson.-Gravels of the Herod member, 25 or 30 feet. thick, were 

exposed in 1904 for some distance in the bluffs along the beach northeast of Fort Salonga, 3 or 

4 miles northeast of Northport. Here the gravels are commonly horizontal, although some 

sections show a slight distt1rbance due to the Montauk ice, also unconformable contacts with the 

Montauk till 1nen1ber (fig. 110). Eastward from this point the Montauk member descends 

gradually to sea level, cutting out the Herod member. The Herod is seen again, however, on 

Nissequogue Neck between Nissequogue River and Stony Brook Harbor (figs. 139 and 140, 

p. 137) and in the vicinity of Stony Brook station (fig. 141, p. 137). Some of the contacts are 

unusually complicated (fig. 140), and much gravel is incorporated in the till. 
126 GEOLOGY OF LONG ISLAND. 

Port Jefferson to Orient Point.-The :first good exposure of the Herod gravel member east 

of Port Jefferson is found half a mile east of Woodhull Landing, where a great thickness of 

gently folded sand and gravel is seen (fig. 111). A quarter of a mile west of Hallock Landing the 

Herod member occurs in both horizontal and upturned and faulted 

masses, as shown in figure 

112. The gravels under-

· lying the t1pthrust Jacob 

sand near Hallock Landing doubtless represent 

the Herod member, as do 

also the· horizontal grav-

.. o 50 Feet els underlying the Mon- .__ ____ ___. tauk till member near 

FIGURE 112.-Section a quarter of 

amilewestofHallockLanding, Herod Point (fig. 113), 0 100 2ooFeef .____ ________ ~----------~ 

showing faulted beds of Herod Paine Landing (fig. 114), FroURE113.-SectionwestofHerodPoint. a,Dunesand;b,banded 

gravel member (a). till (Montauk till member); c, Herod gravel member. 

Hulse, Fresh Pond, and 

Jericho landings, and other points. The Herod member is exposed also as slightly warped 

beds beneath the Montauk till member near Friars Head (figs. 115; and 179, p. 153) and near 

Roanoke Landing and ·Point (fig. 144, p. 139), and it 

probably forms a ·considerable part of the material in 

the bluffs from Roanoke Point to the vicinity of Luce 

0 .____ _____ __. 1oofeet 

FIGURE 114.-Section near Paine Landing. a, Till (Monta:tk 

till member); b, thin clay layer belonging to Montauk member; c, Herod gravel ml)mber. 

o..__,__ ______ ·.:.:zo:._ ____ ____:.40.Feet 

FIGURE 115.-Section near Friars Head, showing Herod 

gravel member beneath banded Montauk till member. 

Landing and Jacob Hill, where it is again definitely recognized. In one section near Jacob I-Iill 

the Herod member is entirely cut out by the pre-Montauk unconformity (fig. 93, p. 109), although 

present in adjacent exposures (figs. 92, p. 109; 157, p. 143). The Herod member was seen 

between Luce Landing and Jacob Hill (figs. 145, 146, 

p.140), also a mile southwest of Duck Pond Point (fig. 116), 

but at many points from this place eastward to the ter-

-------·;.._=-·------==-----==;.,-_ -------------·· ---------

mination of theN orth 

Fluke at Orient Point 

the gravel is absent, 

the interval being rep- ~·~~1\1 0 .____ ____ · _. ~oFeet :.--=d-=--= ----------------------

·----------------------- .. ~4.-:::..--==,....- resented by an erosion FIGURE 117.-Section northwest of Shinnecock Canal, showing folding and faulting in gray clay beFIGURE 116.-;-Section 1 mile southwest of Duck Pond unconformity extend- longing to the Jacob sand and in the Herod gravel 

Point. a, Dune sand; b, Wisconsin till; c, Montauk ing downward into member of the Manhasset formation. Fossils 

0 -_-_ -=--------=-~-_-_--:._ ---:..--=---=:-_-_ ~---:--

till member; d, Herod gravel member. (probably secondary) at f. the .Jacob sand (fig. · 

96, p. 110). Figure 97 (p. 110), however, shows the Herod in its normal relations. 

Bethpage terrace.-The altitude and thickness of the I-Ierod member north of the moraine 

indicate strongly that it must be represented to a greater or less extent south of the moraine, 

·but no exposures admitting of definite recognition are found between the moraine and the 

vicinity of theW est or Mannetto Hills. Near the clay pits at Bethpage, at the south end of these 

hills, and immediately west of Farmingdale, a mile farther south (see Pl. III, p. 28) are two 

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MANHASSET FORMATION-HEROD GRAVEL MEMBER • ~27 

well-marked 'terraces nearly 2 miles long and half a mile to a mile or more wide, composed of 

granitic gravels. The fact that what appears to be the l\1onta'uk till member occurs at the top 

of the Half Hollow Hills, just east of this locality, at an elevation of 240 feet, seems to show 

that the terraces at Bethpage and Farmingdale are to be· correlated with the Herod member. 

The deposits in general are rather coarse, especially at the Bethpage locality, where they contain 

a large number of pebbles and seem to represent the beginning of the transition into the l\1ontauk till member. 

Eastern Long Island.-As indicated on the geologic map (Pl. I, in pocket), the Manhasset 

formation occurs beneath thin coatings of outwash or in many places probably rises above the 

outwash material, ·south of the outer (Ronkonkoma) moraine from the I-Ialf Hollow Hills 

eastward to Great Peconic Bay, but the exposures do not permit the identification of the particular member of the :Manhasset to which 

they belong. It seems probable, however, 

that the I-Ierocl member is mainly below sea 

level in this area. 

Rockaway Ridge.-The ridge extending . 9 1oo zooFeet 

from Far Rockaway northeastward to Lyn- FIGURE 118.-Section northwest of Shinnecock Canal, showing folding 

brook rises distinctly above the Wisconsin out- and faulting in Herod gravel member. 

wash and has a much older topography. The gravel of the ridge differs from that of the normal 

.J:Ierod member in several particulars. The first of these is the unusual amount of quartz 

contained in it; in fact, at first sight quartz appears to be the only material present, a fact 

which led Woodworth 1 to place the deposits in the Tertiary.· l\1ore careful search, however, 

has developed the presence of many granites, and wells sunk along the ridge penetrate the 

Gardiners clay after passing through the gravels. The latter are therefore younger than the 

former and older than the outwash; hence they must be placed in the Manhasset form~tion. 

Their position and the absence of any record of till or other deposits that could be correlated 

with the l\1ontauk point to their being the southern representative of the Herod gravel member 

of the north shore. 

The granite pebbles observed were all of the acidic type and were waterworn and rounded. 

0~--------------------------------------------~ 

Most of ·them were deeply 

weathered, thereby differing 

noticeably from the similar 

pebbles on the north shore-a 

· feature resulting from their 

greater exposure to the weather. 

Many of the quartz pebbles 

were from 4 to 6 inches in diameter, and a large n urn her of 

FIGURE 11!.1.-Section east of Cedar Point, northeast of Sag Harbor, showing disturbed beds of them exhibited a ·very mar ked 

Herod gravel member beneath Montauk till member. ·By D. W. John~on. 

and perfect faceting similar to 

that on the pebbles of Nantucket and Cape Cod, which the writer's work shows to have come 

from the same horizon. 

South Fluke.-The I-Ierod gravel member doubtless occurs at a large number of points on 

the South Fluke, but as the sections are covered with talus and as the key beds (Garcliners clay 

and l\1ontauk till member of l\1anhasset) are absent at many places, it can be identified only 

with difficulty at those points. Good sections were observed in 1904, however, west of Shinnecock Canal, about midway between the canal and Red Cedar Point, where the beds were folded 

and faulted in a marked degree (figs. 117 an~ 118). · Broken Pleistocene shells of secondary 

origin were found in the upper part of the member. On Jessup Neck, about 4 miles west of Sag 

I-Iarbor, several exposures of disturbed gravels, possibly belonging to the Herod member, were 

seen, and on the west side of Hog Neck, about 3 miles northwest of Sag Harbor, there are several 

good exposures of the Herod, the relations being as f?hown in figures 151 and 152 (p. 142). Near 

Cedar Point the section shown in figure 119 was noted. Between Cedar Point and Sammys 

1 Bull. New York State Mus. No. 48, 1!.101, map. 
12~ 1 GEOLOGY OF LONG ISLAND. 

Beach, 4 miles northeast of Sag Harbor, are many exposures of folded and faulted gravels, 

some of which appear to. be overlain by the Montauk till member and hence are to be referred 

ao'r-----------------------'-------------------~ 

FIGURE 120.-Section between Cedar Point and Sammys Beach, .o 

northeast of Sag Harbor, showing folded gravels (Herod gravel FIGURE 121.-Section east of Cedar Point, northeast of Sag Harbor. a, Hemp- member?) with cobble (a) and clayey (b) layers probably repre- stead gravel member; b, Montauk till member; c, folded and faulted gravels senting Montauk horizon. (Herod gravel member). 

to the Herod member (fig. 120). The disturbed gravels shown in figures 121 and 122 are also 

probably I-Ierod, as are the gravels and sands below the unconformity in figure 123. One of 

0~------------------------------~ FIGURE 122.-Section east of Cedar Point, northeast of Sag Harbor, showing disturbed beds of Herod gravel member 

overlain by till (Wisconsin?). 

FIGURE 123.-Section west of Sammys Beach, showing probable unconformity separating Herod gravel member and Hempstead gravel member. 

the exposures in the Montauk region is represented in figure 109 (p. 124), which shows a broad, 

low fold of the Herod member as.it appears in a cliff sectio~ between the Napeague and Hither. 

o so toofeet L------~~----~ FIGURE 124.-Section near Culloden Point, Montauk. a, Dune sand; b, 

Wiscoasin till; c, folded gravel (Herod gravel member?); d, banded 

Montauk till member. 

0 100 .. ·300Feet 

FIGURE 125.-Section 1 mile north of Quince Tree Landing, Montauk, showing folded beds of Herod gravel member. 

Plain 'life-saving stations. On the north shore disturbed or. overturned gravels, apparently 

belonging to the Herod member, are seen near Culloden Point (fig. 124). Other but more obscure 

exposures are found along the shore between the point and the landing 

near the railroad station. West of Rocky Point many exposures of 

folded gravels, possibly of the Herod member (fig. 125), were noted, 

but in general their relations were not disclosed. Near Quince Tree 

Landing, on N apeague Bay, however, the gravel is clearly seen to 

underlie the Montauk till member in one section, and in another it is 

banked against Jacob sand in an upturned mass (fig. 126). 

Robins Island.-The I-Ierod gravel member js exposed in broad, 

0 2sFeet open folds at many points in the bluffs on the west side of Robins 

FIGURE 126.-section ~ miles Island (figs. 98, p. 110; 193, p. 156). At one point there appears to be 

northof Quince'rrceLanding, a strong erosion unconformity due to the action of. the Montauk ice, 

Montauk, showing upturned which, however, left no deposits (fiba. 194, p. 157). A little farther alonba beds of Herod gravel member (a) resting against clayey an important overthrust fault was seen, the upper part of the Herod' 

Jacob sand (b). member being shoved bodily over the lower part toward the south 

and the beds of the lower part being distinctly upturned and crumpled by ·the drag (fig. 127). 

On the other side of the island the exposures are poorer, but there are long stretches of 

upturned and disturbed sands, overlain in places by the Montauk till member, which are 

apparently to be referred to the Herod member (fig. 128). At one point the gravel beds exhibited 

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MANHASSET FORMA_TION-HEROD GRAVEL MEMBER. 129 

~distinct contortion in addition to the broader tlndulations (fig. 74, p. 99). An tlpturned mass 

is shown in figure 75 (p. 99). 

Shelte1· Island.-Owing to the fact that wave ctltting is relatively less active on Shelter 

Island than on the north shore of Long Island, more of the cliff sections here are covered with 

talus. Traces of folded sands and gravels, 

however, were noted at many points along 

the lower parts of the bluffs on the north 

side of the island. This material seems 

to belong to the I-Ierod men1ber, for it is 

stratigraphically below the heavy till 

correlated with .the :Montauk member, 

which is well developed on the island. 0 100 Feet L---------l Gardiners Island.-The .complexity 

f h f ll. d h · f l FIGURE 127.-Section on west side of Robins Island, showing thrust fault in 

0 t e o c 1ng an t e covenng O ta us Herod gravel member. 

on most of the more gravelly bluffs of 

Garcliners Island make the tracing of the Herod gravel member very difficult. As no gravel 

beneath the Gardiners clay is here known, and as profotlnd folding appears to be distinctive of 

the :Montauk invasion, it is fair to presume that the great masses of the strongly folded glacial 

gravels of the island belong to the I-Ierod member. The conditions can be best shown by the 

I~~=::=:<i~l¥ g~iJ i~~f~~~~~~~:~~t;~:~~~~1 FIGURE 128.-Scction on cast side of Robins Island, showing disturbed beds shows the Jacob sand and I-Ierod member in 

of Herod gravel member. thick and but slightly disturbed beds a little 

beyond. The contact is stained black and is more or less oxidized, suggesting a soil zone. A 

few hundred feet farther east horizontal Herod material was seen beneath an overturned fold 

of Gardiners clay (fig. 81, p. 100). On the northeast side of the island, near the west end of the 

bluffs and not far from the base of the sand spit, the relations 

illustrated in figure 78 (p. 100) were observed. At 980 paces from 

the end of the bluff the I-Ierod member was again seen in a gentle 

fold (fig. 129), and beginning 1f miles from the end of the bluff an 

almost continuous section of folded beds of the I-Ierod gravel 

member was to ·be seen in 1904 for a distance of 1,350 feet (fig. 

80, p. 100), beyond which folded beds of the I-Ierod were seen 

intermittently to Eastern Plain Point, a mile farther on. On the 

shores of Tobacco Lot Bay the I-Ierod member appears to have 

suffered more from the Montauk ice erosion and is less seen. The 

accompanyi:ng section (fig. 130) shows the appearance of the best 

exposure near the point at the south end of the bay. South of 

FIGURE 129.-Section half a mile south 

of west end of blufl' on northeast coast 

of Gardiners Island. a, Herod gravel 

member of Manhasset formation; b,gray 

Jacob sand; c, dark-gray to black clay 

alternating with laminre of fine sand 

(Gardiners clay). 

the point there are fine exposures of buff horizontally stratified sands and gravels, which probably belong to the I-Ierod member. · · 

Plum Island.-West of the steamboat landing 

on Plum Island the first good exposure of the Herod 

gravel member seen along the shore in 1904 was 

FIGURE 130.-Section near point at southend of Tobacco Lot fotlnd about half a mile from the wharf in an open 

l3ay. a,Till(partlyMontauktillmcmber);b,Hcrodgravel fold (fig. 102, p. 111). The next quarter of a mile 

member; c, block clay weathering green, with some pebbles. 

showed a succession of similar folds, though not so 

well exposed at the time of the writer's visit. At the west end of the island, near the 

lighthouse, a .thrust !atilt with the upper layers bent tlpward was seen. The fault plane 

makes an angle of about 45° with the horizon. The thrust is toward the south (fig. 131). 

1629°-14--10 ; 
130 GEOLOGY OF LONG ISLAND. 

On the south side of the island the I-Ierod member was seen in considerable thickness a 

quarter of a mile east of the west end of the bluffs, where it has the relations shown in figure 

170 (p. 146). A hundred paces farther east it was again well exposed and showed a great number 

. of parallel faults (figs. 82, p. 101, and 132), and a few hundred yards 

__ ·-:,:_-_:::::::::_.._:/.--· beyond it appeared in a highly folded mass. From this point to 

:::::::::::::~.::f-._::-:: ~--. . . . .···l·· Fort Terry, although the expo- - ~:~:::_:::::-:.;1~::~~~--:- I · sures are not so good, the member 

: _____ :_-~-~-"":~-----.~--.\":-_-_-:::·_-_-_::~ lp·s. st~~).at t~~~t~!~:a:il~fi!~s~O~f o ~Feet 

.__ _ ___. 1 o Feet the fort several fine exposures FIGURE 131.-Section near lighthouse · 

at west end of Plum Island, show- FIGURE 132.-Details of faulting in Herod gravel ShOW highly disturbed and eroded 

ing folds passing into faults in Herod member near west end of bluffs on south side beds of the Herod member (fig. 

gravel member. of Plum Island. 

104, ·p. 111), and a little farther oP, 

a good exposure of the Herod has till backed up against it. From this point to the east end 

of the island and westward along the north coast to the wharf the cliffs have been covered 

artificially and no exposures are now visible. 

Fishers Island.-On Fishers Island the Herod member is best exposed in the clay pit, 

where the sanely phase is strongly developed in the big anticline. The relations and structure 

at this point are well shown in figure 84 (p. 101). Figure 133 shows additional ·details of the 

structure, although owing 

to the talus present the 

relations are not entirely 

revealed. 

At Isabella Beach and 

at the bluff three-fourths 

of a mile northeast the 

Herod member is arched 

.i_, I 

•oo. Fe,et 

FIGURE 133.-East-west section in clay pit on Fishers Island, showing disturbed beds of Herod gravel 

member of Manhasset formation overlying Gardiners clay. 

in broad open folds (figs. 86, p. 102; 134, 135). The conditions at the West Harbor locality 

(fig. 173, p. 147) are sin1ilar to those at Isabella Beach, except that the materials are moderately 

coarse gravels with pebbles the size of a hen's egg. The greater part of the high bill on the south 

so feet 

shore south of West Harbor appears to be composed of the Herod member, which seems to be 

cross-bedded on an extensive scale, and which~ 

to judge from the outcrop of the Jacob sand on 

which the beds rest, is folded irito broad. arches 

only a few feet high. 

Except at the localities described, where the 

gravels rest on the Jacob sand, the Herod metnFIGURE 134.-Section through hill three-quarters of a mile northeast b b · d · h b 1 

ofeastendoflsabellaBeach,Fisherslsland. er Can not e recognize Wlt a SO Ute Cer- . . tainty, although there i.s every reason to believe 

that the yellow and buff sands and gravels seen at a great number of points beneath the thin 

coating of Wisconsin till, forming, in fact, by far the greater part of the island, belong to this 

member. They proba- c 

hlyre~hili~grea~t ~~-·~~ ·:~~- .. ... . • • ~~~~ • 0 :o'."o··.· ... ··o·.o.•.·. 

&vcl~m®~ either m 

the high hills south of · FIGURE 135.-Section parallel with beach at headland three-quarters of a mile northeast of east end 

west Harbor, already of Isabella Beach, Fishers Island. a, Till; b, gray sand belonging to Herod gravel member; c,-clayey 

mentioned, or in the sim- gravel bewnging to Herod member; d, greenish-gray clay (Gardiners clay). 

ilar hill southeast of Chocomount Cove, which rises more than 120 feet above sea level and is 

probably composed mainly of the Herod member. 

Deposits penetrated by wells.-The tripartite division of the :Manhasset formation (the Tisbury of Veatch) was not fully established in the first season's work and is not n1entioned in 

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MANHASSET FORMATION-HEROD GRAVEL MEMBER. i3I 

the report on water resources. The supdivisions can be recognized, however, in many of the 

well records, and from these the accompanying table has been drawn up._ The table includes 

only those wells in which the gravel is found below the Montauk till me;mber. The Herod 

gravel member, however, is recognized in the beds overlying the Gardiners clay and the Jacob 

sand in many other wells, practically all ot those listed under these two formations indicating 

also the presence of the Herod gravel member of the :Manhasset formation. 

No.a Locality. 

Herod gravel memb~ of Manhasset formation in wells of Long Island . 

Owner or place. Depth of formation. Charact.er of materials. Correlation with name used 

in original records. 

38 Brooklyn.. . . . . . . . Bartlett Street and Flushing Avenue. 

Feet. 73--81 Coarse glacial sand........................ Wisconsin and Tisbury. 

62 ..... do .....•...... TenEyck Street ........... . 186 Tallman Island.. . Railroad test boring ........ . 200 Jamaica South .... Baisley pumping station ... . 52-75 

b 57-76 

97-106 

69-98 

56-114 

36-59 

60-123 

22-50 

30-55 

23-37 

53-90 

75-136 

44-70 

70-125 

63-92 

63-73 

64-

38-100 

Coarse yellow sand and gravel. ........... . Sand (not quartz gravel) ................. . Yellowish sand and gravel ............... . Grayish and yellow sand ................. . 'risbury. 

Pleistocene. 

Tisbury.-

220 Hollis ............. Brooklyn test well No.7 ... . 246 Elm Point ........ H. B. Gilbert .............. . Fine sand to coarse gravel. ............... . Do. 

Do. 

258 Hewlett Point .... G. B. Wilson ...•............ 357 PortWashington .. T. Valentine ............... . Coarse gray sand ......................... . White and yellow sand ................... . White sand .............................. . 

Not correlated. 

Tisbury. 

366 ..... do ............ Dodge estate ............... . 421 Nuneola .......... Commission test well ....... . Yellowish sand and gravel ............... . Do. 

Do. 

422 Albertson .............. do ..................... . ..... do ................................... . 

~g ~f~~a<r':::::::: ~-r~:~g,~l~~:::::::::::: Finesand ................................ . Not correlated . Tisbury. 

Do. 

Do. 

Do. 

Sand ..................................... . 457 Glen Cove ......... F. E. Willets ............... . Light-colored sand ....................... . 465 Dosoris ........... W. M. Valentine ........... . 

!~ -~~~~~~~~~:::::: ~: ta~~~:::::::::::::::::: 

Brownish sand and gravel •••.............. White and orange-colored sand and gravel. White sand and gravel. .................. . Tisbury and Mannetto. 

Tisbury. 

484 ..... do ............ W. D. Gutherie ............ . \Vhite sand .............................. . Tisbury and Mannetto. 

Tisbury. · • b 25-85 Do. 

485 ..... do ................. do ..................... . 629 West Neck ........ Mrs. M. H. Clots ........... . Sand and gravel.. ....................... .. Fine brown sand .•........................ 

a Numbers refer to well records in Prof. Paper U.S. Geol. Survey No. 44. b Tn part. 

The persistency of the Herod member is not qnly indicated by its outcrops but is also brought 

out and emphasized by the well records. Its character seen1s to be very uniform, the member 

being usually described as a white, light-gray, yellow,. or brownish sand with gravel indicated 

in about half of the records. Although ranging from fine to coarse in texture, it appears in its 

most common phase to be medium grained. In development it shows the same differences in 

wells as it does in outcrops, the recorded thickness ranging from 10 to 60 feet. Some of the 

apparent differences are probably explained by imperfections in the records, but 'the greater 

part of them are doubtless due to erosion by the Montauk ice, as in the surface exposures. 

Among the well records showing the character of the IIerod member is that of the railroad 

test boring on Tallman Island, near College Point. The section as shown by a sketch by C. M. 

Jacobs, consulting engineer, in the museum of the Long Island Historical Society, with the 

correlation of the writer, is as follows: 

Record of railroad test boring on Tallman Island, New York. 

Recent: Sand and trap bowlders; old sea beach ..................................... .-

Hempstead gravel member of Manhasset formation: Yellow quartz sand ............... . 

Montauk till member of Manhasset formation: 

Quartz gravel and bowlders ................................................... . 

Yellow quartz sand, medium fine ............................................... . 

'rrap bowlders, quartz sand, and gravel; regular glacial drift ...................... . 

Herod gravel member of Manhasset formation: 

Sand .............. : .................. ~- ........................... · ........... . 

Quar.tz gravel ..................................... · ........................... . 

Gravel and sand ............................................................... . 

Quartz gravel ................................................................ . 

Cretaceous(?): · 

Soft clay ....... _ .... _ ......................................................... . 

Lignite intermixed with clay bands ............................................ . 

Streaked red and white cia y; hard, bored out as a solid core ..................... . 

Fordham gneiss: Soft white micaceous ''sandstone" .................................. . 

Feet. 

0 - 7.3 

7.3- 30 

30 - 31. 5 

31. 5- 50 

50 ~ 57 

57 - 63 

63 - 66 

66 - 73.3 

73.3- 76.3 

76.3- 79.3 

97. 3- 91. 7 

91. 7-110. 4 

110.4-159 
132 GEOLOGY OF LONG ISLAND. 

The Herod member is also indicated in the record of a well (No. 366) on the Dodge estate 

near Port Washington, gi'ven in the discussion of the Jacob sand on page 113; in the well of 

the Commission on Additional Water Supply for New York City near East Williston (No. 421), 

given in the discussion of the Montauk till member on page 149; and in the Commission well 

near Albertson. (No. 422). In the well of F. E. Willets, near Glen Co'Ve (No. 457), the following 

section was recorded : 

Record of F. E. Willets's well near Glen Cove. . . 

Wisconsin drift and Hempstead gravel member of Manhasset formation: 

Bro"'n loam ............................................. :., ........................ . 

Brownish gravel and sand ........ : ................................................ . 

Montauk till member of Manhasset formation:. "Hardpan"; clay with bowlders ........... . 

Herod gravel member of Manhasset formation: 

Light-colored sand ......................................... : . ..................... . 

Brownish clay ....... · ............................................................. . 

Sand, growing whiter as the depth increases ..................................... · ... . 

Cretaceous (?): 

Clay, with enough grit to make it hard ("hardpan") ................................ . 

White gravel (no water) ..................... · ....................................... . 

White coarse sand, with an abundant supply of water ............................... . 

AGE. 

Feet. 

0- 9 

9- 29 

29- 44 

44- 70 

70- 85 

85-158 

158-164 

164-182 

182-186 

As already noted in the discussion of the age of the Gardiners clay and the Jacob sand, 

the Herod gra'Vel member of the :Manhasset seems to represent water-laid deposits marking 

the nearer approach of a great ice sheet, the first effect of which was the mflux of sandy material of the Jacob formation, bringing the Gardiners stage of clay deposition to a close. This 

· ice sheet eventually invaded the region, producing the erosion features which are everywhere 

pronounced and leaving the thick Montauk till member. The deposition of the gravel was 

merely an incident of the invasion and belongs to the same glacial stage, which is considered 

to ha'Ve been the equivalent of the Illinoian stage of the central United States. 

MONTAUK TILL MEMBER. 

NAME. 

The term Montauk till member is applied to the middle of the three subdivisions of the 

Manhasset formation. It is at the horizon of the deposits described by J. B. Woodworth 1 as 

~ the bowlder clay bed of the Columbia (Manhasset of his geologic map), occurring in the gravel 

pits of Hempstead Harbor and vicinity. More detailed study has shown it to be present throughout the island and to reach an especially strong development on the south side of :Montauk 

Point, from which it takes its name. The ¥anhasset bowlder bed of A. C. Veatch is the thin 

western representative of this member, 2 but the name M~nhasset can not be applied to it 

because that name is preoccupied for the formation as a whole. 

CHARACTER. 

General composition.-The Montauk member in the western third of the island appears 

at first sight to consist of coarse, roughly laminated sands, in which many pebbles and bowlders are irregularly embedded. A closer examination, however, shows that the spaces between 

the visible sand grains are practically .everywhere filled by a clay or quartz flour. At the west 

end of the island, west of Hempstead Harbor, the member abounds in bowlders and is often 

spoken of as a bowlder bed. The pebbles and bowlders consist mainly of biotitic granite or 

gneiss and although many are much weathered they show signs of glaciation. Quartz pebbles, 

which are very common in the gravel beds above and below it, are scarce in the Montauk member. 

Near the center of the .island the bowlders form a less conspicuous part of the member, 

which here consists mainly of faintly laminated sands with an irregular sprinkling of. pebbles 

and of bowld~rs. 3 to 6 inches in diameter. The amount of clay present averages n1ore than 

1 Bull. New York State Mus. No. 48, 1901, pp. 627-630. 2 Prof. Paper U. S. Gool. Survey No. 44, 1906, Pl. VII and elsE\where. 

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MANHASSET FORMATION-MONTAUK TILL. MEMBER. 133 

farther west, es.pecially near the top of the member, where a pebbly clay is not uncommon. 

Bowlders, though not conspicuous in the exposed sections, are nevertheless pres~nt in considerable numbers, being thickly strewn along the beaches and over the floors of the erosjon 

amphitheaters. Most of the pebbles and bowlders consist of acidic types of granites and 

gneisses. 

In the Riverhead district and farther east the till is much more clayey, clay constituting in 

some sections, especially on the South Fluke, a large part of the member. Through it, however, are scattered many pebbles and bowlders, here largely of Triassic trap and sandstone. 

On the two flukes the till ranges from the faintly banded cl~y, sand, and bowlder type, like 

that noted as occurring in the center of the island, to the clay type of the Riverhead district, 

the l~tter phase being especially common at the top of the member. Cretaceous fossils are 

-·found in the till at Montauk. , 

. Till and gravel phases.-Although in its typical development the Montauk member may 

be defined as a laminated till, it exhibits many variations in character. The lamination is 

likely to be found anywhere strongly marked, and the clay and sand to be assorted into laminre 

and layers, giving the whole mass a definitely stratified character. The gravelly phase is generally coarser and more irregularly stratified and carries both more clay and more granitic 

material than either the underlying Herod gravel me;m.ber or the overlying Hempstead gravel 

member. Transitional phases are commonly not difficult to recognize, but the pure gravel 

type, unless it carries berg-dropped bowlders or bowlder pockets, can seldom be identified 

with certainty. The gravelly phase is most common in the western part of the island, and 

the till phase is perhaps most persistent in the central part. Near the east end gravelly phases 

are also common, but here, instead of the whole bed giving way laterally to gravel, it is more 

common for only a part of the bed to undergo this change, gravels and sands being interbedded 

with till layers. . 

Lamination.-The lamination mentioned is very characteristic 'of the Montauk member,.-

probably being visible in fully 95 per cent of the exposures, and from the fact that it is 

exceedingly rare in the Wisconsin drift it affords one of the best means of identifying the Montauk member. It might be called incipient stratification. It is usually inconspicuous when 

seen close at hand, especially in unweathered exposures, but it generally appears sharp when 

seen a few feet away. The appearance of lamination seems to be produced in some places by 

an alignment of scattered pebbles, but it is more commonly due to differences in texture, which 

although indistinct in fresh exposures are brought out clearly by differential weathering. The 

layers giving rise to the laminated aspect are more like bands than definite strata and are not 

distinctly separated from the adjoining mass. 

Cementation.-The cementation of the Montauk materials is, next to the lamination, 

the most characteristic featur·e of the till phase, being observable in more than 75 per cent 

of the exposures of that phase. The material is cemented into a mass difficult to penetrate 

with a pick and impossible with a shovel. Such material may weather like soft rock, giving 

rise to· the knife-edge ridges and needle-like pinnacles that are very characteristic of what 

is commonly known as "badland topography.". The cementation, however, is not confined 

to the till but is present in the. gravel phase of the Montauk member at many pomts. The 

best illustration of this feature is afforded by the gravels of Lloyd Neck, which, though not 

forming pinnacles like the till, nevertheless show a sharpness of noses and gullies not seen in 

any other gravel on the island. 

Oolor.-The normal till of the Montauk member has a dull bluish or gray color, du13 in 

part to the high percentage of erratic fragments present and in part to the gray color of the 

quartz-flour n1atri~. Probably 75 per cent of the till exposures show this color. Of the 

remainder perhaps 5 per cent are of. a· dull gray-buff'colo:f;:.in p~rt i'estilting from. the. smaller 

proportion of granites present and •in part from a slight staining of the quartz. . : :·- . . 

In the Riverhead region some of the till is discolored by the fragments of Triassic sn.ndstone that it contains, and some has a superficial staining due to wash. On the South Fluke 

and to a less extent elsewhere n1uch of the body of the till is colored greenish, dark gray, or 
134 GEOLOGY OF LONG ISLAND. 

red by the Gardiners ciay worked into it. At one or two points on the north shore quartz 

pebbles derived from the Cretaceous, the Mannetto gravel, or the Jameco gravel give the Montauk member an abnormally light color. Chalky grayish-white shades are also conspicuous 

beneath kettles containing peat, where the till is locally bleached. 

Oxidation.-As indicated above, the Montauk is normally of a grayish color and, except 

where exposed at the surface, presents to the eye little evidence of oxidation. In some 

of the more sandy and porous phases, however, recognized by their buff color, incipient oxidation is observed. Where it rests in its normal position beneath the Hempstead gravel member there is no special weathering of its upper surface, hence its unconformable contact is doubtless the result of ice action rather than of sub'aerial erosion. Where the till was at the surface before the advance of the Wisconsin ice it appears to have been somewhat deeply weathered, 

but most of the weathered part was reworked and incorporated in the Wisconsin drift. Deep 

weathering is to be seen in some of the thick till of :Montauk, Plum Island, and other localities. 

SOURCE OF 'MATERIALS. . 

The materials of the Montauk till member are evidently of glacial origin, a large percentage 

of the fragments showing clear signs of glaciation, and the method of their accumulation indicating association with or at least close proximity to an ice sheet. The coarser materials, 

including the bowlders throughout the larger part of the member, are clearly derived from 

the area of crystalline rocks in Connecticut. The Triassic material so abundant in the district 

near Riverhead is likewise derived from Connecticut outcrops. Of the finer material, a part 

was probably derived from the deposits of Long Island Sound, but the greater portion seems 

more likely to have come from the Herod gravel member, the Jacob sand, and the Gardiners 

clay, which, as has been indicated, were all deeply eroded by the l\1ontauk ice. The part that 

the Gardiners clay ha$ contributed in places is clearly shown by the large quantities of colored 

. clays reworked into the till on the South Fluke from Riverhead eastward. 

RELATION TO OTHER DEPOSITS. 

As· is brought out in detail in the sections relating to the distri,bution of the Gar~iners 

clay, the Jacob sand, and the Herod gravel member of the Manhasset formation, there is considerable variety in the relation of the Montauk till member to the underlying beds. The drift 

in some places rests conformably on the Herod gravel member (fig. 113, p. 126), but in others, 

where the erosion by'the Montauk glacier was severe, it rests on the Jacob sand (fig. 93, p. 109) 

or even upon the Gar9.iners clay (fig. 62, p. 93). The underlying beds are almost invariably 

disturbed and in niany places are highly folded and faulted. 

In eastern Long Island, as stated in .more detail on pages 201, 207, and 208, there were 

several advances of the Montauk ice, the las_t of which folded, crumpled, and faulted the 

underlying strata, including the earlier beds of the Montauk member, but deposited little or 

no till. As a result, the Montauk member in places has an unconformable upper contact (fig. 

178, p. 153), even though the normal sequence was not interrupted, thus supplying an example of what may be called contemporaneous erosion. 

In the greater part of eastern Long Island the ice seems to have lingered until the closing 

stages of the Manhasset accumulation, the Hempstead gravel member, which farther west 

marks the final stage, being commonly absent, and either the original or the ice-eroded Montauk 

surface being left practically uncovered until the mantle of Wisconsin till was sprea'd over it. 

Owing to the reworking of the surface by the ice sheet that deposited the later·drift, it has been 

impossible to determine the extent of the weathering. 

STRUCTURE. 

The Montauk till member is commonly less disturbed than the underlying deposits, mainly 

bec~use the latter received the brunt of the first vigorous advance of the glaciers, before the ice 

became overloaded with drift and began to deposit. In fact, throughout the. western twothirds of the isl~nd the Montauk deposits are but little disturbed, for the ice apparently never 

-· 

.. 
•: 

·-

.. _ 

•· 

MANHASSET FORMATION-MONTAUK TILL MEMBER. 135 

regained sufficient vigor to produce either erosion or folding. In the eastern third of the 

island, however, and on the adjacent islands, the period of deposition appears to have been 

~ollowed by a resumption of ice activity, bringing on a period of scouring, folding, and faulting 

even more vigorous than the first. 

DISTRIBUTION. 

West of Little Neck Bay.-An examination of the cliff sections west of Little Neck Bay 

seems to reveal the presence of two sheets of till separated in some places simply by an erosion 

unconformity and in others by the unconformity and a gravel bed. This region taken by itself 

affords few certain data for differentiating the deposits, all of which might belong to the Wisconsin. The lower till, however, shows the tendency to make abrupt transitions and to break 

up into irregularly stratified gravels which is characteristic of the Montauk member but which 

is rarely if ever seen in the Wisconsin of Long Island. Moreover, although the exposures are 

much interrupted, the till when followed step by step toward the east, appears to become more 

definite and to pass into the bowlder-bed phase of Hemp-_ 

stead I-Iarbqr. It therefore seems probable that the lower 20'.~.:. .'o :;,,·,_,., ... , .o.:_c:·. o<> •:ro:<-.-ci·.· 

till. of the region west of Little Neck Bay belongs to the 

Montauk. member. The best section was that seen in the 

bluff one-third of a mile east of College Point, where the 

relations were as shown in figure 136. 

Great and ll:lanhasset necks, North If.empstead.-On d.__--_-.=_-__________ _.. 

Great Neck, North Hempstead, where the cliffs are not <;>b- FIGURE 136.-Section one-third of a mile east of Cold b 1 i:fi · 11 d f h l\"' lege Point, showing Montauk till· member (a) bescure y ta us nor art Cia y covere , traces o t e· :tOn- neath Hempstead gravel member (b). 

tauk till member were observed here and there between 

the :Herod and Hempstead gravel members, but only on ·Manhasset Neck were clear-cut exposures seen. Among the best of the cliff sections was that at Barker Point, on the east side of 

the entrance to Manhasset Bay. The section as observed by J. B. Woodworth 1 is shown in 

figure 137. The section as exposed when seen by the writer in 1904 showed the same succession 

but with more ma:rked disturbance of the beds .. 

East of Barker Point, around the north end of :Manhasset Neck, the exposures, although 

poor, show traces of the :Montauk till member .at many points.· The till'is best exposed, however; 

in the gravel pits facing Hempstead Harbor, south of Bar Beach. In these pits the Montauk 

member is represented by a relatively thin bed, usually ranging from 3 to 15 feet in thickness, which is remarkably persistent, being exposed in the same position in pit after pit. The 

bed here consists of ~ plastic or sandy bluish micaceous clay 

matrix in which are thickly embedded pebbles and glaciated 

bowlders of various sizes, some of them several feet in diameter. 

At this point there is no noticeable disturbance or erosion at the 

contact with the underlying beds. The large bowlders are here 

a characteristic feature of the formation, a feature which becomes 

still more marked in eastern Long Island and southeastern Massachusetts. So numerous are the bowlders along Hempstead FIGURE 137.-Section at Barker Point, 

Manhasset Neck. a, Wisconsin till; b, Harbor that ·the bed may be traced, where not otherwise exposed, 

Hempstead gravel member; c, Montauk by the talus of large rocks trailing down the hillsides. Comtill member; d, Herod gravel member. 

AfterJ. B. woodworth. pared with those of the Montauk member, the Wisconsin bowlders 

. are few and small. Heaps of Montauk bowlders in the gravel 

pits represent the unusable residue of. the bed. Although in some respects among the best 

exposures on the island, the Manhasset Neck pits show the Montauk member in one of its 

weakest developments, the bed being not only thinner and less characteristic than at many 

other points but also lacking the usual accompaniment of folding and erosion. 

Hempstead Harbor to Oyster Bay.-Traces of the Montauk member were seen in some 

temporary exposures near Roslyn and at intervals to Glen Cove Landing. Just north of Weeks 

Point a very good exposure showing 20 feet or more of Montauk of the characteris~ic compact 

I Bull. New York State Mus. No. 48, 1901, p. 629. 
136 · GEOLOGY OF LONG ISLAND. 

handed type was seen in 1904 (fig. 88, p. 108). A short distance to the north the till gives way 

to an equal thickness of the highly irregular gravelly phase of the Montauk. From this place 

to ~ocky Poi.nt, 2 miles north of Oyster Bay, the bluffs are either obscured by talus or artificially 

covered. At Rocky Point, however, there are several fine exposures of the characteristic 

banded till of the :Montauk m_ember merging into semistratified gravels _resting unconformably 

on the Gardiners clay and the Herod gravel member of .the :Manhasset formation (fig. 65, p. 96). 

At Coopers Bluff, on Cove Neck, the gravel phase seems to be strongly developed, although 

obscured at the time of the writer's visit. 

Lloyd Neck.-N ear· the west end ,of the bluffs three..:.fourths of a mile southeast of Lloyd 

Point there is 50 feet or more of gravel of a very unusua] type (Pl. XXII, B). It rests in apparent conformity on the Cretaceous, which is well exposed in the vicinity. It con.<sists of irregularly bedded sand and gravel, the latter predominating. The pebbles are commonly from 1 

" to 3 inches in diameter, but there are many layers of coarse gravel in which not a few of the 

pebbles are from 4 to 6 inches in diameter. Quartz is, relatively speaking, sparsely represented. 

The great mass of the coarser material is granitic, giving the cliff a rather dark color compared 

with most of the cliffs of the island. At several points the pebbles were found to be much 

weathered, even the larger ones falling to pieces under the hammer and some of them crumbling 

in the fingers. Elsewhere the material appeared to be relatively fresh and firm. One of the most 

noticeable features of the gravel is its semi-induration, brought out in Plate XXII, B, which, 

although a face view, shows the noses and erosion channels very distinctly. These features 

appear still more sharp when seen in profile and afford a strong contrast to the outcrops of other 

gravels. 

In its weathering the bed resembles to a certain extent the Mannetto gravel; but it differs 

from that formation in that the decay is not universal, that relatively littl~ quartz is present 

though granites abound, that it averages much coarser in texture 

than any known Mannetto, and that its pebbles are unstained. 

The highly granitic character suggests some- of the descriptions of 

the Jameco gravel as found in certain wells, but this gravel 

belongs below sea level, and in the absence of any evidence of folding on a scale to bring it up over a broad area there seems to _be 

no possibility of correlating it with the Jameco. In its texture 

and in its cementation it differs widely from the Herod gravel FIGURE 138.-Section east of Lloyd Point, b b t · · t · th th ]1 h f th M 

Lloyd Neck. a, Wisconsin till; b, Mon- mem er, u on comparmg 1 Wl e grave Y P ase o e ontauk till member; c, Cretaceous. . tauk till member we find more resemblances. As has been 

pointed out, this member, while normally a banded till, in some places grades into irregu]arly 

stratified gravels, which, though nowhere exposed on so large a scale as the gravels on Lloyd 

Neck, in small outcrops present the same appearance. In their cementation especially these 

gravels resemble those of the Montauk member, the only geologic division on the island above the 

Mannetto gravel that exhibits this feature. In fact their cementation, together with their 

peculiar stratification, affords an almost certain means of identification. The gravels at this 

point are therefore regarded as a local phase of the Montauk till member. The exceptional 

weathering of a part of the gravels is regarded as due to the incorporation of portions of ledges 

or of older deposits in which decay was already in progress but had not yet reached the stage 

of disintegration. The correlation is made more certain by the presence of the Montauk member in its normal phase resting against the opposite or. east side of the Cretaceous knob, the 

relations at this point ~<:ing as shown in figure 138. The Montauk member appears to sink 

below sea level where the beach curves toward the north half a mile farther east (fig. 175, p. 152), 

but it is seen again at several places for half a mile northwest from East Fort Point (fig. 176, 

p·. 152). The Montauk ~ember at this point is ·a fine-grained, clayey, compact, semi-indurated 

till, whereas the overlying Wisconsin is a loose, weathered, and not at all indurated till, with 

niany large cobbles and small bowlders. The difference in color of the two deposits was 

striking and could be perceived readily by ·the eye at a distance of a mile. · Actinically, however, the difference was _not so great and the photograph reproduced as Plate XXII, A, does 

not show the contrast. 

.. 

·• 

.. 
U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 82 PLATE XXII 

A. CONTACT OF WISCONSIN TILL WITH MONTAUK TILL MEMBER AT LLOYD 

NECK. 

B. GRAVELS (MONTAUK MEMBER OF MANHASSET FORMATION ?) ON LLOYD NECK. 

Showing composition and erosion. Ph otograph by G. N Knapp. 
·-

·-

MANHASSET FORMATION-MONTAUK TILL MEMBER. 137 

West J.Veck.-In the large abandoned clay pits near the south end of Lloyd Beach, on 

Cold Spring Harbor, a considerable thickness of semistrati:fied till of the Montauk type is seen 

above the Cretaceous clay. . The sections differ greatly but show a general resemblance to 

those on the north shore of Lloyd Neck. The thickness in the northerly pits is more than 30 

feet, but in those farther south it ranges from 20 to 25 feet. 

Little Neck, Huntington.-Half a mile south of Little Neck Point a bed of till about 20 

feet thick containing many quartz pebbles was seen above the Cretaceous clay. Its relations 

were not shown, but from its thickness, which would be 

very abnormal for the Wisconsin at this point, it is believed v·~· .. :.·;.~:.:,::-,;•:.;m.:·~.>.<;.~:o: ·,:o .. :-::.:·:o.". 

t~cf~~o:!:~k~b:v~i~J;~;~~~~~01~~da !~e;;~;:~~Ya~~!~ .. ~.,!.--.~.!!!!};~~.~:~~~~~ gravels (Herod member~). The same till still farther north _----: v 

grades into stratified beds of the type characteristic of the ·:<::!~ .. ·. :. 'c? ~ ~ :::::~" o·.~ <?: ~:".:o:~ ~ ;: 

!!ravelly p, hase of the Montauk member. o 0. • .. " · · f> a· · · "/r,r:"" •·· C?· ...... .. · ., • o. A · o h';f~'. o ~ o 

E 7\T k d • • • Al h h 'd f M o<> • • • '·C> Lr-'o!> •• Cl. "l';-;/!/;::~ Q• l-aton 1.vec an mc~n~ty.- t oug ev1 ences o on- c. •• f?.o. • · :? · v-3' ...... /~:J;y::::::..':.... __ 

tauk erosion are pronounced on Eaton Neck, few exposures ~-~~_;.-5?~~~~~.... -=-

of the drift are seen. Figure 66 (p. 97) shows a few feet of i · · 30, Feet .. 

the banded Montauk, as exposed near the base of the West' FIGURE 139 _~sectionmidwaybetween Nisscquogue 1 

Beach sand spit, on the west side of the neck. Other expo- RivcrandStonyBrookllarbor. a, Wisconsintill; 

· b t f fifth f 'l t th th b,Hempstcadgravclmember; c,M:ontauktillmem- SlUeswereseena OU OUr- SO amle 0 enor ,near ber;d,Herodgravclmembcr. ByD.W.Johnson. 

Eaton Point and a quarter of a milesouthof EatonN ecklight. 

A quarter of a mile east of East Beach, which connects Eaton Neck with the mainland, the 

Montauk member was seen in the bluffs, and just west of the broad salt marsh the bluffs exhibited 

in 1904 a considerable thickness of the Montauk, 

separated by a sharp contact from the overlying 

brown loamy Wisconsin till. 

Fort Salonga.-In the bluffs east of the road 

leading to the beach from Fort Salonga, 3 miles 

northeast of Northport, are several fine exposures 

of the Montauk member. At the first of these, 

half a mile east of the road, 25 feet of gravel of 

10 feet the gtayish semi-indurated and semistrati:fied 

l?wunE 140.-Section showing details of the Montauk-Herod con- drift was seen beneath a few feet of structureless tact at the locality shown in figt1re 139. a, Montauk till member; yellow Wisconsin till. A few hundred feet to the 

b, Herod gravel member. By D. W. Johnson. 

west the till graded laterally into gravel. The 

marked unconformity and ~listurbance between the Herod gravel member and the Montauk 

till member shown in figure 110 (p. 125) was near this point. A short distance farther east a 

fine section of indurated Montauk was noted. The Montauk was also seen above the Cretaceous 

clays west of the road to the beach. 

Smithtown Bay region.-On the neck between Nissequogue Bay and Stony Brook Harbor 

the bluffs were com1nonly covered with talus, but a number of sections showing the Montauk 

till mernber resting upon 

disturbed beds of the Herod 

gravel 1nember were noted, 

the contac.t being in places 

hi!!hly 1

·

1

•

1

.e!!tllai; (figs. 139 FIGURE 141.-Roadside section near Stony Brook station, showing contact of banded Montauk till ...., ....., ...., member with Herod gravel member. By.D. W. Johnson. 

and 140). A similar expo- ,; 

sure was seen in a roadside cut near the Stony Brook station (fig. 141). 

Crane Neck and Oldfield points.-The exposures of the Montauk south of Crane Neck 

Point rank among the best on the island, although its relations to the other beds are not well 

shown. From 30 to 40 feet of till is here shown, the lower 20 feet consisting of massive material 

with only feeble indications of banding. The upper part gradually becomes banded and then 

laminated and finally gives way at the top to gravel. One of the features of the exposure is 

an immense bowlder over 20 feet in diameter, occurring in the middle part of the till. On 
138 G:EOLOGY OF LONG ISLAND. 

the north side of the point the bluffs are mainly talus-covered, but the Montauk till member 

appears to continue for half a mile. On Oldfield Point, 2 miles east, the exposures are poor, 

but the bluff appears to consist largely if not entirely of till, the greater part of which appears 

to be Montauk. 

Port Jefferson to Wading River.-On the east side of Port Jefferson Harbor the exposures 

are poor,- but the talus seems to indicate that the Montauk till member occurs low down, possibly extending below sea level. It probably rises inland, but it is not recognized in the big 

gravel pit south of Port Jefferson. East of Mount Misery Point, along West Beach, 20 feet 

of till was seen in places. This contains a bed of -bowlders as much as 1 or 1-t feet in diameter, 

having an aggregate thickness of 4 or 5 feet: The till grades into gravel laterally and probably 

represents the Montauk member. 

From this point eastward to Wading River nothing that could be definitely correlated 

with the Montauk member was noted. The bluffs in the interval show folded and in places 

faulted sands and gravels, the disturbance being of a magnitude comparable with that produced by the Montauk ice rather than by the Wisconsin. This feature would indicate that 

the Mont~uk, if present, occurs at a higher level than any exposures sho·wn in the bluff, an 

assumption which is borne out by the fact that the next exposure of the Montauk-at Wading 

River-is at the top of the bluffs. 

Wading River to Fresh Pond Lan0ing.-Between East Landing and Herod Point, northeast 

of Wading River, the Montauk member reappears as a semi-indurated banded till at the top 

of the bluff, having a thickness of more than 20 feet (fig. 113, p. 126), but it soon disappears 

again. That its position is above the bluff sections is indicated by the disturbed character 

of the gravels. Near Paine Landing, three-fourths of a mile farther east, a thick bed of till 

of the Montauk _type caps the bluffs and covers the slopes' with its talus. The underlying 

layers are somewhat warped and eroded (fig. 114, p. 126). Just west of Hulse Landing the 

following section was measured in a gully: · 

Section west of Hulse Landing. 

Feet. 

Recent: Dune sand........................................................................ 3 

Montauk till member of Manhasset formation: 

Irregularly banded sands and gravels with bowlders................... . . . . . . . . . . . . . . . . . . . . . 15 

Pinkish sandy clay with pebbles........................................................ 1 

Gray banded till, semicemented........................................................ 5 

Herod gravel member of Manhasset formation: Horizontal sands and gravels................... 40 

A_ similar section was seen in 1904 about 100 paces east of Hulse Landing at a point where 

the upper bowlder-bearing gravel was 20 feet thick and the lower till 10 .feet thick, the intervening clay having disappeared. The till in this vicinity carries many large bowlders, hundreds 

of which lie upon the beach a,nd extend out into the water, marking the former extent of the 

deposit. Some of them measure over 20 feet in diameter. A quarter of a mile to the east 

the Montauk member appears to reach a thickness of 50 to 60 feet but is of a grayish gravelly 

type rather than the usual· compact partly cemented drift. From this point for half a mile 

eastward the till continues along the top of the bluff above 75 to 90 feet of the Herod gravel 

member. 

Friars Head.-The most typical exposure of the Montauk till member on Long Island 

was seen· in the vicinity of Friars Head, about a mile north of Baiting Hollow and 6 miles 

northwest of Riverhead. Now here else are the cementation, banding, and characteristic erosion so well shown. The drift is about 30 feet ·thick and consists of a mixture of sand, 

pebbles, and bowlders with some clay, which, with the help of percolating waters, has bound 

the whole mass into a firm, compact body that resists a hammer almost like a soft sandstone. The material seems, however, to loosen under the influence of water and has been 

eroded into sharp knife-edge ridges and needle-like pinnacles resembling the typical badl~nd 

topography.- This characteristic is well shown in Plate XIX, B, in which a thin layer of loose 

_ .. 

• 

• 
.. 

.... 

MANHASSET FORlY.[ATION-MONTAUK TILL MEMBER. 139 

Wisconsin till appears on top at the left. The view shows only small erratics, but bowlders 

6 or 8 feet in diameter are seen at many places. Many of the fragments consist of trap and 

appear to have come from the Tria!3sic areas of Co~necticut. Some of 

them are weathered and rotten. So tenacious is the _matrix that the 

bowlders· stick to the almost vertical faces of the bluffs until it is almost 

entirely removed from around them (fig. 142). 

The banding of the Montauk member, which is faintly seen in a near 

view, is much more apparent from a distance, as brought out in Plate 

XIX, B (p. 114). The banding does not depart much from the horizontal, 

although it is here and there warped into broad undulations, as shown in 

figure 143. A near-by exposure shows the Herod gravel member beneath 

the till (fig. 115, p. 126), and a short distance to the east the Montauk is 

overlain by the I-Ien1pstead gravel member and Wisconsin till. 

Roanoke Landing to· Orient Point.-East of' Friars Head the Montauk 

n1ember is seen at short intervals for a distance of 2 miles, to a point 

nearly north of Riverhead, being in places represented by till and elsewhere by gravel phases (fig. 179; p. 153). A good exposure of the gravel 

FIGURE 142.-Section of pinnacle of Montauk till member near Fri3.rs Head, ill us: 

trating tenacity of matrix 

as shown by projecting 

bowlder. 

was seen in a ravine a little west of Roanoke Landing, although near by the till phase was 

well developed. The following section shows the condit~ons near the landing: 

Section near Roanoke Landing. 

Feet. 

Recent: Dune sand ................................................................. ·_...... 10 

Hempstead gravel member of Manhasset formation: Buff, irregularly stratified sand and graveL 20 

Montauk till member of Manhasset formation: Banded till with bowlders (possibly includes some 

Herod gravel member at base) ............................................ · ...... :.......... 80 

The Montauk member is reduced in thickness toward Roanoke Point, 

where it is represented by a 15 to 20 foot bed about two-thirds of the way up 

the bluff. It is in places clayey and here and there is tinged red by the wash 

N, 

from sandstone fragments, which with many 

s. trap bowlders have been brought .from the 

Triassic area of Connecticut. Some of these 

bowlders reach 15 feet in diameter. The 

beds under the Montauk are in places strongly 

50 Feet . , folded. Near Roanoke Point the Montauk is 

FIGURE 143.-Section near Friars Head, show- found at the top of the bluffs and merges with 

mg character of erosion and undulations of the Wisconsin till, but farther east it is seen 

c 

banding in Montauk till member. in a lower position persisting as a reddish bed FIGURE 144.-Columnar 

section east of Roanoke 

15 feet thick at 80 to 100 feet above the beach (fig. 144). It has afforded 

large bowlders at several points. 

A poor exposure of the Montauk member banked against upturned Jacob 

sand was seen at the landing west of Jacob Point (fig. 91, p. 109), but this 

Landing. a, Hempstead gravel member; 

b, Montauk till member; c, Herod gravel 

member. 

member was not again observed between this lan,ding and a point half a mile beyond Luce 

Landing, where the following section showing doubtful Montauk occurs: 

Section east of Luce Landing. 

.. Feet. 

Recent: Dune sand ............................................................ ~........... 5 

Wisconsin: Buff till merging downward into gray till ......... · ............................... } 

Montauk till member of Manhasset formation(?): Gray tilL.................................. 15 

Herod gravel member of Manhasset formation: Irregularly bedded sand and graveL............ 60 

A section just beyond is shown in :figure 145, and another a quarter of a mile farther east in 

:figure 146. In neither place is it absolutely certain that the till is Montauk. The till continues 

with sin1ilar relations for another quarter of a mile and then disappears from the bluff sections, 

although it is probably present higher up in the hills, as the_lower peds are strongly folded. The 
140 GEOLOGY OF LONG ISLAND. 

sections shown in figures 93 (p. 109) and 182 (p. 154) were observed in 1904 near Jacob IIill. 

The till was of the normal banded, semicemented type. 

The next exposure suggesting the Montauk member. was seen about half a mile east of the 

c 

0 so Feet ~------------~ 

west end of the Oregon Hills, where a bowlder 

bed of granites and Triassic traps and sandstones appears in the middle of the bluffs (fig. 

147). The mass was stained reddish by wash 

froiD: the sandstone fragments and in places 

graded into a sand. A quarter of a mile 

farther east a 10-foot bed of gray till overlain 

by cross-bedded ferruginous cemented sands 

FIGURE 145.-Section half a mile east or Luce Landing. a, Dune sand; and gravel (the gravelly phase of the Montauk ~) b, till (mainly Montauk till member); c, Herod gravel member. 

was exposed. A mile southwest of Duck Pond 

Point occurs the section shown in figure "116 (p. 126). Near this point several pockets of 

bowlders were observed at the horizon of the Montauk and probably represent that member 

(fig. 148). Farther east a persistent bed of cobbles was followed for several hundred feet. 

A mile and a half east of Duck Pond Point the following section was measured: . -

Section 1~ miles east of Duck Pond Point. 

Feet. 

Recent: Dune sand ................... :._. ______ ._ ............... _ ........... _ ... :._ ........ _ 3 

Wisconsin: Bowlder tilL ____ ... _ .. __ ._. ____ ._ ... _. ____ ...... _._. ____ ._ ..... __ ... __ .. _..... 5, 

Mont.:'tuk till member of Manhasset formation: Banded, semicemented sands with pebbles irregularly distributed through the mass. __ .---.-- .. _. ____ ._~ .... ___ .. ___ .. ____ ._ ...... _ ... __ .__ 10 

Herod gravel member of Manhasset formation: Gravel and sand. _ ...... __ . __ ... _ ..... _. _.... 12 

Between the localitj last mentioned and a point a quarter of a mile south of Inlet Point, 

northwest of Greenport, large quantities of till were seen, much of it crowded with bowlders. 

The washing 

away of the 

finer parts of 

the till has left 

~=== .. -;;-,--- d a thick fringe of 

"--:.;.~:...-=-;·:: _ ... _ bowlders along 

o .sofeet the beach, in 0 .40 Feet 

FIGURE 146.-Section three-quarters or a mile . S 0 me plaCeS east or Luce Landing. a, Dune sand; b, fine FIGURE 147.-Section at Oregon Hills, showing layer of cobbles and 

banded till (Wisconsin or Montauk); c, Mon- piled in great bowlders, presumably representing the Montauk till member. 

tank till member; d, Herod gravel member. heaps. The exposures do not in general permit the differentiation of the Montauk member from the Wisconsin, but it is thought that a considerable part of the n1aterial n1ay belong to the Montauk. 

[ -~ ~ 

--== ===----

FIGURE 148.-Section ncar Duck Pond Point, 

showing fault and bowldcrpocket(Montauk till 

member) in gravels of Manhasset formation. 

FIGURE 149.-Section a quarter or a mile south of Inlet Point, showing relation of 

Wisconsin till to Montauk till member. 

The accompanying section (fig. 149) shows the relation of the Wisconsin and Montauk at a 

point a quarter of a mile south of Inlet Point. In general the Montauk appears to be a pebbly 

rather than a bowlder till. 

From Inlet Point" to Orient Point much the same conditions prevail. The Montauk member 

for the most part can not be separated from the Wisconsin till with certainty, although the thick-

·• 

-· 
.• 

.. 

MANHASSET FORMATION-MONTAUK TILL MEMBER. 141 

ness of the mass at many points and the extent to which the underlying beds have been folded 

seem to prove that the Montauk is represented (fig. 96, p. 110). A bowlder pocket similar to those 

formed at Oregon Hills and vicinity was noted three-fourths of a mile south of Rocky Point 

(north of Greenport), resting in a depression in theMontauk. This pocket deposit was of a type 

transitional between the till and ordinary gravel, consisting of interlaminated sand and clay 

with pebbles and small bowlders scattered through it. -

East Williston.-N ear the village of East Williston, about 3 miles south of the head of 

I-Iempstead Harbor and .about a mile south of Ronkonkoma moraine, a clay pit in a shallow 

depression of the outwash surface exhibits the following section: 

Section in clay pit at East Williston. 1 

Feet. 

Soil. ............ -. -... -...... -. -------......................... -. -.... -.......... --...... - 1. 5 

Sand, gravelly, with quartz and granitic pebbles, locally reddened .. ·. ________ ...... __ ...... ·1 

Clay, sandy, ~vith quartz pebbles .................................................. -......... 8 

Clay, sandy, m yellow band ............................................................... . 

Clay, blue, finely laminated, rarely 'vith quartr. pebbles; exposed ..... _ .... _ .................. 3 

In addi.tion to the quartz pebbles the writer found in the.pit many small pebbles of rotten 

granite and in a near-by well a greenish biotitic sand such as would be expected to result from 

a decomposed bowlder. Heinrich Ries 2 reports unidentifiable stems and leaves. The bed is 

of smaH extent, wells a mile away generally failing to encounter it. 

The age and origin of this clay present a rather puzzling problem. Ries and Crosby seem 

to refer it to the Tertiary, but recent observations show that it not only contains glacial pebbles 

throughout but is also underlain by glacial gravels. In all probability it is to be referred to 

the Montauk member of the Manhasset or to the Wisconsin till, representing reworked Cretaceous 

materials, Gardiners clay, or deposits of the Vineyard interval. In favor of the Montauk origin 

may be mentioned the clayey character of the material and the advanced decay of the granites, 

although these might represent older deposits reworked into the Wisconsin. Against the 

l\1ontauk origin is the altitude of the bed (150 feet), which is somewhat greater than the normal 

elevation of the Montauk member in this region. On the other hand, the altitude is what 

might be expected of an extramorainal deposit of Wisconsin till, but against the Wisconsin origin 

may be urged the thickness of the deposit, its extent (apparently half a mile or more), and its 

clayey character, aU of which are abnormal for lenses of the later <;lrift. On the whole the 

writer feels that the deposits will most likely prove to be Montauk. · 

Half Hollow Ilills.-An examination of the materials forming the terrace-like top of the 

I-Ialf Hollow I-Iills discloses irregularly bedded gravels considerably· coarser than the gravel 

m.embers of the Manhasset and containing scattered ·bowlders, now seen on the terrace surface 

and on the slopes and at the foot of the hills. The largest bowlders were noted on the road leading into the hills 1! miles northeast of Wyandanch. T4e materials of the hills most nearly 

resemble the Montauk member, with which they are provisionally correlated. 

Middle Island region.-The surface of the region between Coram and the headwaters of 

Peconic River is characterized by many bowlders and some patches of material resembling 

tilL Inasmuch as there is considerable Wisconsin drift in the region, as indicated by the 

superficial morainal topography and the obstruction of the Manhasset valleys, it is difficult 

to differentiate the surface n1aterial, but it is thought that a part of the bowlders and till may 

represent the l\1ontauk n1ember. 

Red Cedar Point.-On the South Fluke, which is here assumed as starting at Riverhead, 

the :first recognizable exposure of the Montauk member to the· east appears about a mile east 

of Red Cedar Point and about 6 miles east of Riverhead. The till appears to begin almost at 

the west end of the bluffs but is not well exposed for some distance. About a quarter of a 

n1ile fron1 the beginning of the cliffs, however, a fine exposure of highly folded and overturned 

I Woodworth, J. B .. Bull. New York State Mus. No. 48, 1901, p. 645. .2 Trans. Ne~v York Acad. Sci., vol. 12, 1893,pp. 40-4i. 
.142 . - GEOLOGY OF LONG ISLAND. 

Montauk and other beds was seen (fig. 150). The Montauk at this point is very clayey; 

consisting of alternating bands of gray and red clayey sand in which ~re embedded large num~ 

hers of bowlders of Triassic trap and red sandstones with some granite. The clayey character 

is believed to be due to the reworking of the underlying Gardiners clay and Jacob sand into 

the till. The mass is superficially stained a distinct red by wash from the weathered Triassic 

fragments, but internally it is of a buff or gray color. The beach in front of the exposure is 

paved with trap bowlders. 

Shinnecock Hills and vicinity.-About half a mile east of Shinnecock Canal, in an old clay 

pit, on the shore of Great Peconic Bay, is an exposure of a pebbly clay type of Montauk till 

oL...--_____ ..:.~soFeet 

overlying and plainly derived from the 

Gardiners clay. In 

the hill north of Cold 

Spring Pond, 1! miles 

farther northeast, the 

usual compact bandFIGURE 150.-Section 2 miles northwest of Shinnecock ed type of Montauk 

Canal. a, Wisconsin till; b, banded clay till with'bowl- till was noted at sev _ ders (belongs to Montauk till member); c, banded 'clay and pebble till (belorigs to Montauk till member); eral points. The full 

d, bowlder pocket. thickness was not exh D o oo 

10 Feet 

FIGURE 151.-Section on west side of Hog· Neck, northwest of Sag Harbor. a, Overturned fold of 

sandy clays with erratic pebbles representing reworked Gardiners clay and belonging to the Mon- t~uk till member; b, Herod gravel member. 

posed, but it is known to exceed 30 feet (fig. 183, p. 154). Bowlders of. the Triassic formations 

continue to be conspicuous. . 

Jessup Neck.-On the west side of Jessup Neck, near the north end of the exposures, 

the section shown in figure 184. (p. 154) was seen. The material is a brownish till-like mass 

of bands of red and gray clay, in which pebbles and cobbles -with some Triassic bowlders are 

irregularly embedded. The Montauk ice after depositing . this mass seems to have become 

more vigorous and to have both folded and eroded the material it had laid down, so that the 

· overlying Hempstead gravel member lies unconformably across the 

c 

top. The surface of the exposure is stained red by the wash from 

the red clay and Triassic material. · 

Hog Neck.-A quarter of a mile south of the north end of the 

bluffs on the west side of Hog Neck, 3 miles northwest of Sag l-Iar- _ 

bor, several feet of greenish-blue clayey till containing both erratic 

pebbles and broken fossils 

was seen, the whole result- <;>._ _____ _;;,z.5Feet. ing from a reworking of 

FIGURE 152.-Section on west side of the underlying Gardiners Hog Neck, northwest of Sag Harbor. a, Till; b, overturned fold of clay with a certain admixcontorted sandy clay with erratic ture of foreign material. pebbles representing reworked Gardiners clay and belonging to the The bed is much folded FIGURE 153.-Section ne3r Hog Creek Point, on South Fluke, Montauk till_ member; c, Herod d t t d t d' showing Hempstead gravel member resting on Montauk till gravel member. an COn or e ' S an Ing member. 

out in the cliffs with the 

relations shown in figures 151 and 152. A quarter of a n1ile to the south a gray to -bluish-gray 

till (Montauk ~) is seen below an upper rusty yellowish to buff till representing the Wisconsin,. 

the two being separated by a very sharp contact. _ 

Cedar Point.__:About two-thirds of the way between Cedar Point and Sammys Beach, 

some 5 miles northeast of Sag Harbor, typical·banded till of the Montauk member was seen 

associated ~th. highly f.olded and faulted gravels, the relations being as indicated in figures119 (p. 127) and 121 (p. 128). , 

Hog Greek Point.-The bluffs between Sammys Beach and Hog Cre/ek Point were generally 

covered with talus, but the greater part of the material appeared to be till, with some banded 

or even well-stratified layers, which, however, merge into true till. At the head of the point, 

near Lion Head Rock, till of the Montauk type. was seen in broad_low folds, the relations being· , 

.. 

: .. 

.-

... 
MANHASSET FORMATION-MONTAUK TILL MEMBER. 143 

as shown in figure 153. Similar relations appear to continue, though less satisfactorily exposed, 

at intervals to the end of the bluffs near Fire Place. Above the till at several points is a series 

of sands involved with the till in broad open folds (fig. 154). Their character and position 

are typical of the Hempstead gravel member, but the folds have been beveled off at the top 

in a manner exactly analogous to the erosion produced by the final readvance of the Montauk 

ice, and the gravels m·ay be simply a phase of the Montauk member. 

FIGURE 154.-Section near Hog Creek Point, on South Fluke, showing Hempstead gravel member resting on Montauk till member. 

0~----------~zofeet 

FIGURE 155.-Section 1 mile west of Rocky Point, Montauk, showing bed of banded Montauk till member 

beneath layer of granitic gravel and cobbles and granitic sand and gravel (Hempstead gravel member). 

Monta'IJ,~ peninsula.-Between Fresh Pond and Quince Tree Landing, at the east end of 

the bluffs on N apeague Bay, the Montauk member was seen poorly exposed in the upper part 

of the bluffs. It is at leas·t 15 feet thick and may be considerably thicker, as there are indications that it may in places extend down to the beach. Just south 

30' of the landing an exposure showing the Montauk member in a broad 

~~~~~~~~~~~o 100 zoo Feet 

FIGURE 156.-Section 1 mile west of 

Rocky Point, Montauk, showing intercalated bed of gravel in Montauk till 

member. 

FIGURE 157.-Section half a mile south of Culloden Point, Montauk, showing intercalated 

sand and clays in Montauk till member. a, Montauk till member; b, clayey sand; c, clay; 

d, gravel; e, sand;/, Wisconsin till. 

fold was seen (fig .. 109, p. 124). Figure 155 shows folded beds of the :Montauk n1ember, as 

seen half a n1ile west of Rocky Point. A near-by section (fig. 156) showed a layer of gravel 

interbedded with till of the Montauk n1ember. Strong talus slopes of till character are seen 

0

Horizon};J scale 200 Feet Vertical scale . F 9 1 :! I I sp I I I I 1?0 eet 

FIGURE 158.-Section east of Montauk Light, showing Hempstead gravel 

member resting on Montauk till member. a, Bufi' sand belonging to 

Hempstead mom her; b, sand, with greenish clayey laminro, belonging 

to Hempstead member; c, sand and fine gravel belonging to Hempstead member; d, iron-stained bowlders and ferruginous conglomerate 

layer at top of Montauk till member; e, sands and gravels ( downfaulted 

beds of Hempstead member?);/, faulted banded beds of Montauk till 

member; g; semistratified drift of Montauk member. 

till mmnber banked against folded beds of 

(p. 128). 

at Rocky Point and vicinity .. 

From Fort Pond to Culloden Point the 

bluffs are largely covered by talus, but till, presumably of the Montauk member, seems to be 

the predominating material. There are indications that thin strata of both clay and sand 

are interbedded with the till (fig. 157). Near 

Culloden Point the Montauk member is exposed for some distanc~ at the base of the bluff. 

Its upper surface is very irregular, but whether 

the irregularity is due to. erosion or to folding 

could not be determined (fig. 187, p. 155). An 

exposure showing what appears to be Montauk 

the I-Ierod gravel member is shown in figure 124 

At Shagwong Point and at the headland just east of Oyster Pond 10 feet or more of 

indistinctly banded l\1ontauk till member was -seen. in· the lower part of the bluffs· beneath 

reddish clay, apparently a local phase of the Montauk, from the wash of which it is stained 

red in places on its exposed surfaces. A quarter of a mile east of the second headland a considerable thickness of the Montauk was observed resting above a dark chocolate-colored clay 
144 GEOLOGY OF LONG ISLAND. 

assumed to be the Gardiners clay. The drift consists of an up.per banded till of the type 

characteristic of the Montauk and a lower more gravelly phase grading laterally into gravel, 

as shown in figure 76 (p. 99). 

The Montauk till member appears again a little southeast of False Point in folded masses 

with dips as high as 30° in places. Some of the exposures were very clear and sharp in 1904. 

0 50 IOOFeet_ L-~------~--------~ 

FIGURE 159.-Section southeast of Montauk Light. a, Till phase of Montauk till member; b, 

bowlder pocket; c, sand and clay phase of Montauk member; d, clayey sand phase of Hempstead gravel member; e, normal sandy phase of Hempstead gravel member. 

· Toward the southeast the till 

sinks below the beach, but it 

rises again near the lighthouse 

(fig. 174, p. 151). The till at 

this point contains many large 

fragments and is somewhat 

banded but is not much cemented. It grades upward 

into a banded clayey till with 

many erratics. 

In the in:imediate vicinity of the Montauk lighthouse the Montauk member is seen in a 

thick bed at the base of the bluff, where it has the characteristic banded development. The 

profile of the extreme point, looking east, was in 1904 as shown in 

figure 189 (p. 155). Figure 158 

(p. 143) illustrates the complexity 

of the exposures just north and figure 159 shows the conditions immediately south of the lighthouse. 

From Montauk Point southwestward to the point marking the 

oL...:...· ______ z_,oo Feet 

FIGURE 160.-Section It miles southwest of Montauk Light, showing red clays intercalated in till of Montauk till member. a, Hempstead gravel member(?). 

abrupt change ·in the direction of the coast line to a more westerly bearing the exposures of 

the Montauk member are almqst continuous. Among the features of interest in this stretch 

is a thick bed of dark-brown to red clay interbedded 

and folded with the till of the Montauk member at a 

point about 1l miles fron1 the lighthouse and half a 

mile from the southerly .point mentioned. Its relations are shown in fibO'ure 160. FIGURE 161.-Section 1! miles southwest of Montauk Light, 

showinggradationcrromlerttoright)orbandedandmassive West of the bend in the coast just mentioned 

Montauk till member and its relations to the overlying Wis- the Montauk is almost continuously exposed for cons in. 

nearly a mile (fig. 192, p. 156). In places nothing 

but till is observed in the bluffs, although it is here divided into an upper loose buff to brown 

·till, probably Wisconsin, and ·a much thicker banded mass belonging to the Montauk. The 

IOO feet 

s~ction is represented in figure 

161, which shows the two tills 

and the gradation of banded 

into massive Montauk till. 1-Ialf 

a mile farther east the Montauk 

shows a thick lens of sand and 

gravel, not unlike the Herod or 

H d b b FIGURE 162.-Section 2 miles southwest of Montauk Light, showing lens of stratified gravel in 

empstea mem ers, etween Montauk till member. a, Wisconsin till. 

two beds of drift (:fig.162). The 

lens is practically· undisturbed, the stratification still retaining its horizontal position. A 

feature of the Montauk in this region is its whitish color beneath kettle holes containing peat. 

Though ordinarily of a buff color, it is here bleach~d to a chalky white, the difference in color 

;I 
MANHASSET FORMATION-MONTAUK TILL MEMBER: 145 

between adjacent masses being noticeable even from a distance. Figure 59 (p. 89), shows the 

Montauk resting on upturned and eroded sands, gr~vels, and clays. . 

Between Ditch and Fort plains there appears to be another.almost continuous exposure of 

the banded till of the Montauk member, but the outcrops are more obscured than farther east 

(fig. 191, p. 156). The upper part seems to be a thin coating of Wisconsin till, which at one 

place thickens to 25 f~t, comprising nearly half of the bluff. Towa.rd the west end of the 

bluffs the Montauk is seen in contact with the underlying gravel. 

West of Fort Pond the bluffs 

of I the south coast seem to be a 

duplication of those near Montauk 

Point, exc~pt that the gravelly 

phase of the Montauk is more comInoiliy present. There is generally 

so feet 

FIGURE 163.-Section on south side of Montauk peninsula between Napeague and Hither 

Plain life-saving stations. a, Dune sand; b, Wisconsin till; c, Montauk till member. 

a sharp dmnarcn.tion between the Montauk and the overlying Wisconsin (fig. 163). · The 

Montauk till is not uncommonly interbedded with stratified clay, sand, and gravel (fig. 164), 

. some of the beds of which reach in places a considerable thickness. 

' The strong development of ,the 

-:-:-:~~~~-----. Montauk member on Montauk. Point, 

25 feet 

FIGURE 164.-Soction on south side of Montauk peninsula between Napeague and 

Hither Plain lifo-saving station<;, showing intercalated clays, sands, and gravels in 

Montauk till member. 

the profiles of the bluffs now cut in the 

south coast, and the offshore rocks and 

bars all point to a former extension 

of the Montauk member con~iderably 

farther sou~h. It is not improbable 

that the :Montauk ice sheet extended . 

some distance into the sea, and in that 

case more' or less Montauk till, if n~t 

eroded by the late :Manhasset ice or in 

the Wisconsin stage, would naturally be found south of the moraine or even beneath the s.ea. 

The only known evidence' of such extension is the uncovering of bowlders and other glacial 

n1aterial by the waves along the coast in the vicinity of Easthampton, noted by Mather. 1 

FIGURE 165.-Section on cast side of Robins Isbmd. a, Hempstead gravel 

member; b, Montauk till member; c, Herod gravel member (?). 

FIGURE 166.-Section on east side of Robins Island. a, Montauk till member; b, Herod gravel member. 

Robins Island.-There does not seem to be any strong development of Montauk op. the 

west side of Robins Island, for although the beds are folded a:o.d faulted as if by Montauk ice, 

only a thin layer of till, which might be either Montauk or Wisconsin, is seen at the top~ Some 

of the gravels c~ntain considerable quantitie.s of clay intermingled with the grains in the sands 

and show more cementation than elsewhere occurs in .the Herod gravel member. The same is · 

true to an even greater extent of some of the gravels of the east shore and it'is not unlikely 

that bo~h may represent the gravelly phase of the Montauk. Near the north end of the bluffs 

on the east side the banded-till phase of the Montauk is locally well developed, although the 

cmnplexity of the disturbance makes its relations un<?ertain. Figures 165 and 166 represent 

the conditions of the exposures in 1904. · · 

Shelter lsland.-Bluff exposures showing the Montauk in section are not known on Shelter 

Island,· although it seems probable that the Montauk occurs under the talus in the lower part 

of son1e of the bluffs. If so, it is likely to be exposed in any storm. The surface till of the 

1 Mather, W. W., Geology of NP.w York, pt. 1, 1843, p. 165. 
GEOLOGY OF LONG ISLAND. 

southern half of the island, especially in the low till plains of the east and south coasts, is 

regarded as probably Montauk, as its thickness is much greater than it seems possib_le to ascribe 

0 100 zoo Feet 

to the Wisconsin, which is thin elsewhere. 

Gardiners lsland.-Traces of banded till resembling the Montauk were visible at many points 

on the southwest coast of Gardiners Island, but 

FIGURE 167.-Section at south end of Bostwick Bay, Gardiners ·no clear-cut exposures were observed. On the 

Island. a, Wisconsin till; b, banded till of Montauk till member; northwest coast between Cherry Hill Point and c, thin layer of green to black clay (Montauk); d, sand and gravel Bostwick Bay a very good exposure of the strongly (gravel ph~ of Montauk till member); fl, Herod gravel member. 

folded and leveled Montauk member was seen, its 

relations being as indicated in figure 167. The contact between the till and the overlying gravel 

phase is marked by a layer of dark-green to black clay from 3 to 5 feet thick, resembling in occurrence that at Shagwong Point, 

on Montauk. In fact, the Montauk member of Gardiners Island 

presents many strong resemblances to that on Montauk 

peninsula. 

On the northeast coast the 

Montauk member is commonly 

[ 0 100 aoofeet 

FIGURE 168.-Section near north end of bluffs on northeast; shore of Gardiners Island, showing 

folding of bed of banded till of Montauk till member with the intercalated clay. 

absent, although its horizon is in plaqes marked by erosion unconformities or by bowlder pockets 

or layers and near the north end a thick bed is involved in a large fold (fig. 168). Near Whale 

Hill it again attains a considerable thickness and is infolded 

with the other beds, as shown in figure 80 (p. 100). At 

., one point a stratum of" red clay several feet thick is inter-

,.:!,! bedded with the till (fig. 169), again, suggestfug conditions 

-::;f;~' similar to those shown in figure 160 (p. 144), at Montauk. 

o Near Eastern Plain Point 'the Montauk forms in places the 

FIGURE 169.-Section east of Whale Hill, Gardiners greater part of the exposures and contains two persistent Island, showing intercalated bed of red clay in till of . Montauktillmember. beds of red clayey sand about two-thirds e>f the way up 

the bluff. These clayey beds tend to confuse the section because of their resemblance to the 

Gardiners clay. Folded Montauk material is again exposed near the south end 

of Tobacco Lot Bay. 

Plum . Island.-The north shore of 

Plum Island does not afford any good 

exposures of till, although there are indications that 'not less than 20 feet of this 

material is present in places, the greater 

part ·of it probably being Montauk. The 

FIGURE 170.-Section near west end of bluffs on south side of Plum Island. a, 

Greenish clay with granitic pebbles (Montauk till member?); b, banded 

Montauk till member; c, Herod gravel member. · . 

southwest corner of the island consists of a' broad bowlderstrewn plain, which rises toward the east, exhibiting till 

of the Montauk type in the bluff sections. It is overlain 

by a greenish clay containing pebbles similar to those in 

some of the exposures on Gardiners Island and on Montauk.· 

The wh<?le plain, except perhaps a thin superficial coating 0 ofWisconsin niaterial, is regarded as belonging to the Mon- . FIGURE 171.--Section east of Fort Terry, Plum 

'Island·. a, wisconsin bowlders; b, Hempstead tauk member. On the east the drift abuts against an eroded 

gravel member(?); c, Montauk till member(?); surface oftheHerod gravel member, as shown in figure 170. 

d, Herod gravel member. From this point east to Fort 'Terry no good exposures of the 

Montauk were seen, but a quarter of a mile east of the fort it reappears with the relations 

shown in figure 171. The bowlders on top of the section are probably Wisconsin. East of 

• 

• 
• 

• 

• 

• 

MANHASSET FORMATION-MONTAUK TILL MEMBER . 147 

thls exposure the Montauk appears resting across the eroded edges of the Herod _gravel 

member and the Jacob sand, as is shown in figure 104 (p. 111). One exposure showed a large 

Montauk bowlder stranded in process of plowing its way through the underlying gravel (fig. 172) . 

The rest of the bluffs on the east end of the island are ~rtificially covered. 

Fishers Island.-On Fi~hers Island the Montauk member is of somewhat unusual character, 

·although the exposures are typical of certain well-defined phases near the type locality. The 

member has been recognized above sea level at only two points-at 

the West I-Iarbor exposures and in the bluff three-quarters of a mile 

northeast of the north end of Isabella Beach. The "bowlders" 

reported in the Ferguson well probably belong to this member. 

· At the West I-Iarbor exposure (fig. 173) the :Montau.k is probably 

represented by th~ heavy bed of till resting unconformably on the ~=:-~~.:_-::.~ ... upturned and eroded edges of the Jacob sand and the Herod gravel 0'--.....,----------1 

1nember. 

At the second locality mentioned the exposures show a series of 

beds of clayey sand alternating with beds of pebbles about the size 

of a hen's egg occurring in a matri-x: of clay or clayey sand. Both 

sand and gravel show the peculiar mixture of coarse grains or pebbles 

FIGURE 172.-Section east of Fort Terry, Plum Island, showing bowlder 

of Montauk till member arrested 

while plowing along the surface of 

Herod gravel'member. 

with fine silts that is characteristic of rapidly formed and only partly assorted deposits such as 

accumulate at the margin of glaciers. The deposit unquestionably belongs to the Montauk substage, representing certain of the more _aqueous ph:ases of deposition. A little farther north, 

c c 50 feet 

FIGURl~ 173.-Artificial section near the steamboat landing on west side of West Harbor, Fishers 

Island (1904). .a, Till (Montauk till member?); b, gravel (Herod gravel member); c, gray clayey 

sand (Jacob sand?); d! gravel (probably lens in Jacob sand). 

although the contact is not 

seen, the semistrati:fied deposits appear to be replaced 

by till. 

Deposits penetrated by 

wells.-Although 'the Montauk was not recognized' as 

a distinct member during 

the :first season's field work, 

it was well known that there was a bowlder bed in the middle of the Manhasset formation at 

n1any places, and it was loo~ed for· in the well records. The compactness of the member, the" 

, presence of bowlders in it, the large number of granitic pebbles that it. contains,. and its clayey 

constitution ·are all helpful in its recognition, and the writer feels that he can identify it in 

n1any records in whlch its presence was not' originally suspected. Its occurrence in wells is 

smnmarized in the table on the next page, compiled from the records in Veatch's report on 

the water resources of the island. 
GEOLOGY OF' L-ONG· ISLAND. 

··.l Montauk till member of Manhassetformation in the wells of Long Island. 

• ~ ·'C • l 

Owner or place. 

·~·· 

23 BrookJyn .... ~ ....... .- Fifth A venue and Eight29 ..... do .•.............. D::~t~t!~:~d Vanderbilt 

Avenue. 

37 ..... do. . . . . . . . . . . . . . . . Bartlett Street and Harrison 

Avenue. · 38 ..... do .•.............. BartlettStreetand Flushing 

Avenue. . 62 ..... rlo ................. TenEyck Street .......... .. 71 · ..... do ................. 99 North Eleventh Street. .. 99 Long Island City...... Grove Street ••.•.••••••..... 

135 East New York ....... New Lots Road and Fountain A venue. ·137 ..... do ............... :. Brooklyn test well No.4 ... _. 

141 ..... do ................ . Brooklyn test well No.5 .... Citizens' Water Supply Co .. Bowery Bay Buildmg Asso151 . .Flushing ............. . 176 North Beach ......... . 

186 Tallman Island ..•.... ciation. 

Railroad test boring ........ . 199 Jamaica South ....... . Oconee pumping station .•.. 200 ..... do ................ . Baisley pumping station ••.. 220 Hollis ................ . Brooklyn test well No.7 .. .. 223 Dunton .............. . Montauk Water Co ......... . 236 Bayside .............. . Commission test well ....... . 

237 ..... do ...................... do ..................... . 

246 Elm Point ............ H. B. Gilbert .............. . 

258 Hewlett Point........ G. B. Wilson ............... . 273 H~wlett............... Queens County pumping station. 

357 Port Washington ...... T. Valentine .•.............. 364 ..... do................. C. H. Mason ................ . 

366 ..... do................. Dodge estate ............... . 373 Long Beach ...... :. . . . Long Reach Association .... . 

·378 Rockville Center...... Commission test well ....... . 402 Greenwich Point ........... do ....................... · 

~ . ~~~~~~~~~-·_:::::::::: :::: :~~::: :::::::::::::::::::: 

421 Mineola ..................... do ...................... . 

422 

436 

446 

456 

4S7 

465 

469 

481 

483 

484 

485 

629 

707 

736 

737 

744 

745 

749 

750 

751 

752 

756 

760 

768 

769 

786 

797 

848 

8S4 

861 

875 

883 

885 

890 

895 

Albert"Son .................. do .... · ............ · ...... . Roslyn ................ Mrs. I. Vowman ........... . Glen Head ............ A. A. Knowles ............ .. Locust Valley......... Friends' Academy ......... . Glen Cove ............. F. E. Willets ....... ~ ...... .. Dosoris ................ W. M. Valentine ..... · ...... . .... ·.do ............... : .. D. F. Bush ............... .. Lattingtown .......... L. C. Wier ................ .. 

:::::a~:::.::::::::::::: ~-~~~~'theria::::::::::::: ..... do ...................... do ...................... . West Neck ............ Mrs. M. H. Clats .......... .. Brentwood ............ Commission test welL. ..... . Lake Ronkonkoma .... William Ralston •........... ..... do ................. J. Weber ................... . Lake Grove........... John Morrissey ........... ~ .. ..... do ........... :..... Irving Overton ............. . St. James .••.......... Commission test well ....... . ..... do ................. FatherDucy ............... . ..... do ................. Jerome Saxe ............... . ..... do ................. D. Emmett. ............... . .. ... do ................. Commission test well ....... . Setauket .............. W. Rowland ............... . Crane Neck ........... John Thatcher ... : ......... . Old Field Point.. ................................. .. Farmingville .......... August Fuch ............... . Echo .................. Commission test welL. ..... . Huke Landing ........ J. H. Darlington ........... . Baiting Hollow.. .. . .. C. H. Wells ................ . Quogue ............... Quantuck Water Co ........ . 

~~!1\~rsfs~a~cL ~:::::: 3i!ei-~~~~~:::::::: :·::::::: ..... do ................. J. N. Stearns .............. .. ..... do ................. Manhasset Hotel. ......... .. East Marion..... . . . . . . W. F. Fursts· ............... . 

DeDth of. 

formation. Character of materials. N arne used in original 

records. 

Feet. 

35- 45 Reddish-brown bdwlder cl!iy .......... Wisconsin and Tisbury. 

56- 81 Brown sand and bowlders............. Do. 

65-150 Red clay with large bowlders......... SanK:aty. 

31- 73 Sand and granitic clayey gravel....... Wisconsin and Tisbury(?). 

b o- 52 

50-100 

33-:- 58 

93-118 

97-141 

192-216 

90-

20- 32 

30- 57 

56-115 

58- 97 

15- 69 

8- 64 

17- 55 

0- 65 

0- 56 

20- 36 

33- 54 

53- 60 

18- 52 

1&- 22. 

7&- 82 

48- 52 2- 3 lo- 11 

3-

7- 26 

3- 21 so- 53 

60- 75 -so- 87 

29- 44 

76- 79 

7- 15 60- 63 

60- 63 60- 64 

38-

10-25 

45- 50 

22- 25 

38-

17- 45 

45- 52 

&- 45 

0- 60 

0-160 

o- 30 5- 70 o- 60 

10- 50 

0-40 

58- 62 

50- 60 

35- 60 

50- 51 

3- 5 

8- 10 14- 20 15-27 

8- 20 

18- 22 

Clay; sand, and bowlders ............. . Rlue clay, gravel, and bowlders ...... . Hard, cemented hard pan and reddishbrown sand and gravel. Reddish-brown sand and gray grav- elly clay. Dirty-gray sand and gravel and gray pebbly clay. Gray clay and granitic silty sand ...... Blue stony clay ••..................... C...ompact mixture of sand and gravel.. 

Till, with interbedded sand ..... , .... . Grayish to dark-reddish brown sand .. . Gray sand and gravel. ••.............. Granitic sands and gravel. ........... . Blue clay and gray sand and graveL .. Black clayey sand and reddish-brown 

sand and gravel. Light to dark·sandy clays, sands, and 

granitic gravel. · Yellow clay with bowlders, gray sand, 

and graYel. Stony clay ........................... . Gravelly clay and dirty sand and gravel. 

Bowlder till ....... ~ ................... . Black marl, loam, with pebbles and 

oyster shells (probably reworked 

Gardiners clay). Bowldertlll .......................... . Quartz p-avel, with pieces of blue clay con taming sand and gravel. Sand and giavel, with,howlders ...... . 'l'ough, sandy clay, with bowlders(?) .. Gray sand and glacial d~bris (?) ...... . Dark silt.to cobbles(?) ............... . Yellow clay, sand, and gravel, with 

bowlders. . .... do ................................ . Sand, with thin layer of bowlders .... . Sand and clay ....................... .. Brown clay .•............ : ........... . Hardpan, with bowlders ••............ Hardpan ............................. . Blue clay, with p~bbles, hardpan ..... . Red clay and gravel, hardpan ........ . Red clay and graveL ................ . ..... do ................................ . Large bowlders ....................... . Hardpan with graveL ............... . Coarse gravels, highly granitic ........ . Black hardpan with pebbles ......... . Clay without bowlders ............... . Coarse sand and large cobbles ........ . Stony gravel. ........................ . Dirty gray sand and graveL.: ........ . Hardpan and bowlders ............... . Stony gravel and clay, hardpan ...... . Coarse gravel. ........................ . Gray sand and granitic gravel. ....... . Hardpan and graveL ................. . Gravel with streaks of hardpan ....... . Hardpan ............................. . Hard stony yellow hardpan .... · ...... . Dirty-gray granitic gravel. ....... ·; .. . Dark-red clay and black sand .•....... Cemented clay and graveL ........... . Sand, clays, and bowlders ............ . Hardpan ............................. . ..... do .......................... ! ..... . 

Hard mixture of clav, sand, and gravel . Hardpan, with sand bed ............. . Hard-packed sand and gravel. ....... . 

Wisconsin. 

Sankaty (?)and Jameco (?). 

Wisconsin or Tisbury. 

Tisbury(?) and Sankaty. 

Tisbury and Sankaty. 

Sankaty. Do.(?). 

Wisconsin to 'fisbury (?). 

Pleistocene. 

Tisbury. Do. 

Wisconsin and Tisburv. 

Do. · Do. 

Wisconsin. 

Wisconsin and Tisbury. 

Not correlated. 

Sankaty (?) 

Manhasset bowlder bed. 

Not correlated. 

Manhasset bowlder bed. 

Sankaty. 

Wisconsin and Tisbury. Do. 

Wisconsin. 

.Do. 

Do. 

Not correlated. . Manhasset bowlder bed. 

Do. 

Do. 

Do. 

Do. 

'Visconsin. 

Manhasset bowlder bed. 

Do. 

Do . Do. 

Wisconsin and Tisbury. Do. 

Do. 

Pleistocene. 

Wisconsin and Tisbury. Do. 

Not correlated. 

Wisconsin. 

Pleistocene . Not correlated. 

Wisconsin and TL'!bury. Do. 

Not correlated. 

Do. 

Tisbury. 

Not correlated. 

Sankaty. 

Wisconsin and Tisbury. Do. 

Not correlated. 

Wisconsin and Tisbury . Wisconsin. 

Wisconsin and Tisbury . Wisconsin. 

a Numbers refer to ~ell records in Prof. Paper U. S. Geol. Survey No. 44. bIn part. 

'l'he differences between the correlations of Veatch and those of the writer, as brought out in 

the last column of the table, seem to be due to the fact that the existence of the member, further 

than the bowlder bed mentioned, was unrecognized at the time of the preparation of the report 

on the water resources, many of the beds being included by Veatch with his Sankaty (Gardipers c1ay) because of their clay content, no other clayey. member then being known. The 

• 

• 

• 

• 
• 

•· 

• 

• 

MANHASSET l!"'ORMATION-MONTAUK TILL MEMBER.. .149 

abseHCe of any; 'inforrnation as to the great unconformity and the consequent abrupt changes 

in level of the beds also tended to make the recognition of the n1ember very difficult. 

Among the well records in which the Montauk till member is recognized the following are 

of especial interest: Well at Bartlett Street and Flushing Avenue; Brooklyn (No. 38), given 

under Jameco gravel on page 86; railroad test boring at Tallman Island near College Point 

(No. 186), given under Herod gravel member, on page 131; the G. B: Wilson well, near Hewlett 

Point, at the west ~?ide of the.entrance to Manhasset Bay (No. 258), given under Jacob sand 

on page 112; and a well on the Dodge estate near Port Washington (No. 366), given under 

Jacob sand on page 113. 

The following is a record of a well near Bayside: 

237. Record of commission's test well near Bayside. 1 

Wisconsin drift, or Hempstead gravel member of Ma~asset formation: Feet. 

Yellow sandy clay.................................................................. 0- 2 

Yellow clayey sand with some pebbles.............................................. 3- 5. 5 

Montauk till member of M~nhasset formation: · 

Dark clayey sand ................................. .-: ................. · ... · ............ 10-18 

Mottled sand and gravel (pronouncedly glacial) ................. ·-~ ...... : ............. 20-29. 5 

Multicolored sa~d and gravel similar to that found below the blue day on the south shore. 35-36 

Dark-yellowish clayey sand (glacial) ...................... : .......................... 40-46 

Dark, multicolored fine to coarse sand (glacial) ........................................ 49-65 

Herod gravel member of Manhasset formation: 

Fine to··coarse.yellow sand with very little glacial material. . . . . . . . . . . . . . . . . . . . . . . . . . . 65-66 

Yellow sand and small gravel with many fragments of ferruginous concretions..... . . . . . . 70-71 

The records of the wells penetrating the somewhat doubtful materials at East Williston 

and vicinity may also be inserted at this point: 

421. Record of commission's test well near East Williston. 1 

Wisconsin: Feet. 

Very dark brown surface loam~ .................. , ................. :.· .... ·......... 0 - 0. 8 

Reddish-brown loamy sand ................................. · ........... :........... 2. 7- 2. 9 

Montauk till member of Manhasset formation(?): 

Yellow clay and bowlders ............................. ~.......................... 7. 5-13.2 

Light yellowish-white sand and gravel. ......................... ·.· ................. 17. 5-18. 5 

Reddish-yellow silty sand ........ : ................................................ 22. 5-23.5 

Very black sand, full of mica, loo~s like ground-up bowlder ......................... 25 -26.5 

Herod gravel member of Manhasset formation (?): 

Fine to medium yellowish-white sand .................. · .......... .' ................ 3'0 -36 

Fine yellowish-white sand to medium gravel.. ....................... ~ ..... ·. . . . . . . . . 40 -41 

Smalllight~colored gravel (considerable percentage of glacial material) ............... 41 -42 

Fine to medium yellowish-white sand ........................................... .'. 45 -51 

Smalllig~t-colored.gravel with glacial material. ....... ·.·.: ..... · ................... 54 -55 

422. Record of commission's test well near Albertson. 1 

Feet. 

Recent black loamy clay........................................................... . 1. 7- 2. 3 

Montauk till member of Manpasset formation (?): 

Brownish-yellow clay with a few pebbles very similar to the clay at East Williston. . . 3 - 3. 5 

Brown and yellow clay with reddish-brown sand and grav.el (glacial); ................. 8 - 9. 5 

Dark-grayish sand with much fresh ~iotite; evidently debris from a glacial bowlder .. 10. 5-11.5 

Yellow clay, sand, and gravel ("bowlder clay") .................................... 15 ..:.21 

Herod gravel member of Manhasset formation (?): 

Sand and coarse gravel (glacial)....... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 -24 

Fine yellow sand with a noticeable percentage of glacial material. ................... 27 -37 

AGE. 

The Montauk till member was clearly deposited, as its character indicates, either beneath 

or at the margin of an. ice sheet. Although in certain parts of Long Island, especially near the 

east end, there are indications of several advances and recessi9ns of the ice, there is no evidence 

1 Numbers refer to Veatch's report. Correlations by M. L. Fuller. 
150 GEOLOGY OF LONG ISLAND. 

such as soil zones or features due to subaerial erosion to indicate any great lapse of time between 

them, and the period of deposition of the Montauk member is therefore to be regarded as a unit. 

The Montauk is the third great drift deposit on the island, the two older sheets from their 

position, thickness, material, weathering, and erosion, being referred to the pre-Kansan and the 

Kansan. If the identification of these earlier drifts, especially the Kansan, is correct there is 

little doubt that the Montauk should be referred to the Illinoian, as the series of deposits is unbroken from the Kansan· or Jameco through the Yarmouth or Gardiners to the Illinoian as 

represented by -the Jacob sand and the Herod and Montauk members of the Manhasset 

formation. 

Beyond Long Island-the Montauk member continues through the New England islands 

into Massachusetts, where it is represented by a typical structureless till, being here a land rather 

than a glaciomarine deposit. The Montauk and the equivalent till of the mainland constitute 

the principal drift of New England, and in. comparison with this body of till all other drift 

deposits are insignificant. In the interior of the United States a great drift sheet emerges from 

benea:th the Wisconsin in western Pennsylvania and stretches westward to and beyond the 

Mississippi, reaching a thickness ·of hundreds of feet' in places and, like its :Montauk equivalent 

in New England, greatly. surpasses in development the other drifts. In other words, in the 

Mississippi-Ohio valley, in New England, and on Long Island the third drift is by far the most 

important of the glacial deposits, and it is not unfair to assume that iJ;l each region it belongs to 

the same glacial stage, the Illinoian. The correlation of the Montauk with the Illinoian is 

rendered more probable by the recent investigations in Europe, which appear to show a close 

agreement of glacial stages with those of the Mississippi Valley and Long Island, as if the 

succession had been not only similar but simultaneous. · 

· To attack the problem of _age from another standpoint, it may be noted that the period of 

erosion between the Wisconsin and the Manhasset (the latter including the Montauk), was of 

great length, being many times greater than that reported between the Wisconsin and the Iowan 

drifts. If not of Illinoian age, the drift must be referred to another ice sheet unknown either in 

the Mississippi Valley or in Europe. That the most powerful sheet and the thickest drift in Long 

Island and New England should belong to an invasion not elsewhere represented is improbable 

if not impossible. If the grave doubts that have recently arisen as to the existence of the Iowan 

in the central portion of the country are justified the number of invasions in the eastern and 

central regions is the same and the correlation of one with the other is made more certain. 

HEMPSTEAD GRAVEL MEMBER. 

NAME. 

Mter the Montauk invasion and it~ attendant erosion, deposition, and folding, the ice 

retreated from Long Island and a series of gravels were laid down, doubtless derived from the ice 

which appears to have lingered in the Vicinity. For these gravels, which represent the uppermost of the three subdivisions of the Manhasset formation, the name Hempstead gravel member 

is here introduced, from Hempstead Harbor, along the west side of which the gravel is finely 

exposed in the upper parts of many large gravel pits. 

CHARACTER. 

The Hemp~tead gravel member is very similar to the Herod gravel member, showing the 

same variations in different parts of the· island. In fact, there is nothing in its lithologic 

character by which it can be distinguished from the Herod member and the description of the 

;Her<;>d given on page 121 applies almost equally well to the Hempstead. If there is any difference it is in the more sandy character of the 'younger member. Because of their resemblance 

the beds can not be differentiated from one another ex?ept where they are associated with key 

beds, such as the Gardiners clay, the Jacob sand, or the Montauk till member of the Manhasset 

formation. 

• 

• 

• 

6' 

• 

•. 
• 

• 

MANHASSET FORMATION-HEMPSTEAD GRAVEL MEMBER . 151 

SOURCE OF MATERIAL. 

What has been said of the source of material of the Herod gravel member is almost equally 

applic,able to the Hempstead gravel member. The only difference to be expected is a smaller 

percentage of material derived from the Cretaceous and Mannetto deposits and a greater petcentage from Connecticut sources. In general, however, the difference is not well marked, the 

I-Iempstead member of western Long Island showing practically as much of the Cretaceous and 

Mannetto material as the I-Ierod member. 

RELATIONS TO OLDER DEPOSITS. 

The normal contact between the I-Iempstead member ap.d the underlying :Montauk member 

is conformable, but, as elsewhere indicated, the final event of the Montauk invasion in the eastern 

part of the island was a vigorous advance 

of the ice, as a result of which botp. the 

earlier Montauk and the underlying beds 

were folded, faulted, and eroded.· As little 

or no deposition attended this last ice ad-· 

vance, the I-Iempstead, where occurring 

above the Montauk in this part of the 

-... __ __ 

,,---------........ 

..... _. ............. .., ·; --...:. ... ________ ...,_ .,, I 

------~- ,' 

100 Feet. -----------..--~~"' 

island, is likely to rest On an erod~d Or FIGURE 174.~Soctioneastof Montauk Light. a, Hempstead gravel member; 

folded surface (fig. 17 4). b, clay with glacial pebbles and howlders belonging to the Montauk till 

member; c, banded till belonging to Montauk member. 

The contact between the Hempstead 

and. the Montauk, even where conformable, is usually sharp and abrupt, but in places a 

transitional phase from a few inches to a few feet thick is observed. Where the contact is 

unconformable it is almost universally abrupt. 

STRUCTURE. 

The Hempstead gravel member is much less disturbed than the underlyillg deposits, the 

overriding Wisconsin ice apparently having been either thinner, less active, or of shorter duration 

than the preceding ice sheets. The folding is .in general rather superficial, affecting but a few 

feet of the gravel ·as brought out in figu:re ·20~ (p. 210) ·and Plate XIX, A (p. 114), although 

there ar'e indications that it was of considerable magnitude in some places where the ice 

pressed against bluffs or other steep slopes . 

. DISTRIBUTION. 

Relation of IIempstead gravel member and Montauk till member.-In western Long Island the 

Montauk member occurs as a thick zone showing abrupt lateral transitions from till to gravel 

or vice versa, so that not uncommonly one exposure shows a thick bed of till. at a horizon at 

which an adjacent exposure s.hows nothing but coarser gravel. Between the extremes are many 

gradations, the till being thin or absent and the gravels relatively thick or the till thick and the 

gravel phase absent. The member, however, appears to be a unit and to represent a single event 

in geologic history. The overlying beds are in general undisturbed. 

Farther east, in the middle portion of the island, the till phase becomes more common and 

persistent than in the west. It still retains its unity, howev~r, and is still overlain by essentially 

:undisturbed beds. 

In the part of the island ~ear Riverhead a marked change appears to have taken place. 

West o( this point the period of Manhasset accumulation seems to have comprised, first a stage 

of aqueous deposition (Herod gravel member), next an ice invasion with the deposition of till 

(Montauk till member), and last a return to aqueous deposition (Hempstead gravel member). 

East of Riverhead the opening stage of aqueous deposition was much the same as at points farther 

west, but the epoch of ice invasion appears to have lasted much longer, continuing well toward 

the. close of the Manhasset deposition. The invasion was· not, however, cQnfinecl to a single 
152 GEOLOGY OF LONG ISLAND. 

, 

advance, as in the central and western parts of the island, and the deposits are not a unit. 

Instead the ice ·appears to have advanced and 'retreated several times, giving rise to the alter-

-nations of till with stratified clays, sands, and gravels 

noted on Gardiners Island, at Montauk, and elsewhere. 

Throughout the whole of the North and 

South flukes and· on the adjacent islands 

exposures that can be certainly correlated 

FIGURE 175.-Section 1 mile northwest of East Fort Point, with the Hempstead member are lacking, 

Lloyd Neck, showing disturbed and faulted gravels ap- for although gravels and sands are found 

parently overlying the Montauk till member. here and there above the Montauk member they appear, even where best developed, as on the Montauk peninsula, to 

have been overridden by a readvance of the ice and strongly folded or faulted. 

That this disturbance is very old, probably Montauk, is indicated by the deep 

subaerial erosion to which the beds were subjected between the time of disturbance 

and the advance of the Wisconsin ice. Unfortunately, however; the evidences of 

subaerial erosion are not everywhere conspicuous, and it is consequently impossible 

to say whether the folding is Montauk, the gravels being Montauk·or younger, or 

Wisconsin, the gravels being p~rhaps as young as the Hempstead member. For· 

this reason it has usually been impossible to differentiate the beds with certainty 

in eastern Long Island. When differentiation is impracticable the beds above the 

Montauk till member will be spoken of .as :the gravels of the upper Manhasset. 

It is noted .that the Hempstead gravel member, although generally absent 

from eastern Long Island,· reappears on Block Island and at places farther east. , 

West of Little Neck Bay.-On the north shor~ near the west end of Long 

Island a bed of sand or gravel in places separates the Wisconsin till at the surface 

from the Montauk till m~mber. This bed occupies the normal position of the 

Hempstead gravel meniber, with which it is probably to be correlated. Among 

the exposures best showing the relations of this gravel is that one-third of a mile 

east of College Point, represented in figure 136 (p. 135). · 

Great and Manhasset necks, North Hempstead.-Traces of the Hempstead 

gravel member between the Montauk member and the Wisconsin drift are seen 

here and there on Great Neck, North Hempstead, but the first clear-cut exposure 

showing the relations was seen at Barker Point, 2 miles northwest of Port Washington village, on Manhasset Neck, where the section shown in figure 137. (p .. l35) 

was found. On the north and northeast shores of Manhasset Neck the exposures 

are poor, but south of Bar Beach on ·Hempstead Harbor the. Hempstead member 

was observed in many gravel pits. Only the lower part, however, was seen, 

the upper part being eroded previous to .. the Wisconsin ice invasion and later 

covered with a thin coating pf Wisconsin till. 

Oyster Bay._:_'The Hempstead gravel member is nowhere well exposed along 

the coast between Hempstead Harbor and Oyster Bay, although unquestion-

. · ably occurring beneath the relatively thi~ Wisconsin till in the highlands back 

from the shore. At Rocky Point, ·2! miles north of Oyster Bay village, an exposure ·about 15 feet thick was seen in a trough of the Monta~k member (fig. 65, 

p. 96), ·and the Hempstead member appears 'to form the upper part of the· bluff at 

Mill Neck, northwest of the village, and at Coopers Bluff, 2 miles northeast. 

Lloyd Neck.-The .Hempstead· gravel.member appears to form th~ upper 

part of the hills on Lloyd Neck beneath the mantle of. Wisconsin outwash and till 

but is seen in few bluff sections. · There is an exposure near the northward curve 

of the beach, half . a mile east of the Cretaceous outcrop and 1 t miles southeast 

of Lloyd Point, where folded and faulted gravel of the upp'er part of the Manhasset formation is exposed. . The character of the exposure is brought out in figure 17 5 and 

Plate X~III, B. A mile farther east a:J?,d continuing to East Fort Point a fine to clayey sand, 

• 

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• 

• 

.. 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 82 PLATE XX III 

A . UNCONFORMABLE CONTACT BETWEEN HEMPSTEAD (1) GRAVEL MEMBER OF MANHASSET 

FORMATION AND CRETACEOUS DEPOSITS ON 

LITTLE NECK, HUNTINGTON. 

B. MANHASSET GRAVEL FOLDED BY OVERRIDING ICE. 
• 

• 

MANHASSET FORMATION -HEMPSTEAD GRAVEL MEMBER . 153 

probably the Hen1pstead member, was exposed above the :Montauk n1ember almost continuously, 

although here and there cut out by erosion during theVineyard stage, especially near the east 

end of the section (fig. 176). · 

Little Neck, Huntington.-In the large clay pit on the east side of Litt.ie Neck, Huntington, 

a little south of Little Neck Point, finely stratified sands and gravel are seen restmg against the 

Cretaceous clay with the relations shown in figure 177. The pebbles in the gravel are fresh 

and at the base there are a number of moderate-sized and· perfectly fresh granite bowlders. 

FIGURE 177.-Section in clay pit near end of Little 

Neck, opposite Northport. a, Slightly weathered 

gravel (Hempstead gravel member?); b, bowlder 

lJed (Montauk till member?); c, greenish weathered 

surface of Cretaceous clays (d). 

The freshness of the· gran- 40•· ....................... .. 

ite seems to preclude its 

being Mannetto, and the 

large and fresh bowlders 

could, so far as is known, 

have been brought in only 

by the Montauk ice or 

floating bergs from its FIGURE 178.-Section near Friars Head, showing 

Hempstead gravel member resting unconform- margin, hence the gravels ably against the Montauk till member. 

are apparently to be correlated with the Ilempstead n1ember. ·The unconformity, which is one of the sharpest observed 

on the island, is shown in Plate XXIII, A. 

Smithtown Bay region.-The Hempstead member is definitely recognized at few places· , 

around Smithtown Bay, but an outcrop on the coast between Nissequogue River and Stony 

· Brook I-Iarbor (fig. 139, p. 137) shows a somewhat well developed bed above the :Montauk till 

1nember. 

The· gravel a~ the top of the bluffs on Crane Neck Point east of Smithtown Bay grades 

downwru·d into the Montauk till member and may probably be regarded as the Hempstead gravel men1ber, or at least as a transition between the Montauk and Hen;1pstead members. 

Port Jefferson to Wading River.-The gravels in the upper part of the 95

';¥:~:~~t~~~ ~ bluffs bordering the east side of Port Jefferson Harbor are 

distinctly above the Montauk till member and are therefore apparently to be referred to the Hempstead member. 

In the big gravel pit south of the town of Port Jefferson 

the gravels are thought to be the Hempstead, at least in 

the upper part, although in the absence of information as 

to the position of the ~1ontauk member, which is the key 

bed, it is impossible to determine the horizon of the gravel 0 c:==--:.----=- with absolute certainty. The Hempstead member appears 

FIGURE 179.-Columnar ' 1 d h f h d ' h ' h bl ff section between Friars to me u e t e greater part o t e epos1~s s own In t e u s 

Head and Roanoke along West Beach north of the town. From this point 

Landing. a, Dune to Wading River there appear to be no unquestionable s1md; b, Wisconsin till; 

c, Hempstead gravel exposures of the I-Iempstead member, the folded and FIGURE l80,_:__Columnar 

member; d, unconform- f lt d h t f th l d th lt' t d f th section near Roanoke it y; e, Montauk till au e C arac er 0 e graVe an e a 1 U e 0 e Landing. a, Dune sand; 

member;/, Herod Montauk n1ember indicating that the gravels are perhaps b, Hempstead gravel 1 b · member; c, Montauk 

grave mem er. to be referred to the I-Ierod member, although the Hemp- till member. 

stead1nemb~r probably occurs in the higher lands back from the coast. 

Friars Head.-From Wading River to Friars I-Iead the· Hempstead member is nowhere 

. exposed, the ~1ontauk being at the tops of the bluffs. A little east of Friars I-Iead, however, 

the· I-Ien1pstead lies lower, nearly 40 feet of buff sand and gravel having the relations indicated 

by figures 178 and 179 being e~posed. The Hempstead rises a little farther on and is absent . 

fron1 the bluffs to a point near Roanoke Landing, where the gravels at the top of the bluff, 

above the gravelly phase of the Montauk member in the center of the section, represent the 

I-Iempstead member. 
154 GEOLOGY OF LONG ISLAND. 

. Roanoke Landing and Jacob HiZZ.:_Near Roanoke Landing about 20 feet of the I-Iemp- , 

stead member was seen above the ::Montauk till member, with the relations shown in figure 

180 (p. 153), and a little east of the landing the section shown in figure 144 (p. 139) was n1easured. 

Near Jacob Hill a considerable thickness of gravel belonging to the upper part of the Manhasset 

formation was seen above the Montauk till, member at 

~a1(eraL points (figs·. 181 and 182). 

zo'p~-· . ". . ., ~ . ~ ~-

~::·0~ 

o z.oFeet 

(j 

0 so Feet 

FIGURE 181.-Section ;,vest of Jacob Hill, showing irregular contact between Hempstead gravel member and Montauk till member (structure poorly exposed). 

FIGURE 182.-Section west of Jacob Hill. a, Hempstead gravel member; b, Montauk till member; 

c, Herod gravel member. 

Oregon Hills and vicinity.-If the bowlder beds and pockets noted near Oregon Hills and 

Duck Pond Point (fig. 147, p. 140) represent the Mon~auk member, as there is reason to believe, 

the gravels above them must be referred to the Hempstead member. 

Rocky Point.---:-Because of the height at which the Hempstead member occurs, very little 

of the gravel is seen between the Oregon I-Iills and Orient Point. About three-fourths of a 

mile south of Rocky Point, north of Greenport, however, several sections show sand and gravel 

over the Montauk till member. The following is a section at this locality: 

Section threefourths of a mile south of Rocky Point. 

Feet. 

Wisconsin: Till. ..................................................... -...... -.- ........... -. 10 

Hempstead gravel member or Montauk till member: 

Sand. and fine gravel.................................................................... 5 

. Coarse gravel ................................................................... -.-.-.-. 5 

Montauk till member: 

Bowlder pocket ...................................... _ ............................. ' .. 1-3 

Semistratified till. ............ ·_ ....................................................... ·. 20 

Ri1.,erhead to Sag, Harbor.-No good exposure of the Hempstead gravel1nember was seen 

between Riverhead and Shinnecock Canal, although traces were seen here and there (fig. 183). 

Half a mile or so east of the canal and in the 'bluffs north of Cold Spring Pond, 1! miles to the 

northeast, gravel, perhaps the Hempstead member, was 

seen at several points above the Montauk till member. _._ n • •• n: ·--:, .. ·_.· ... ·• ~ ·_:_··:·/··. ~-··:·· .·::· ;·:·:.,-:::;-:·>: ]; 

0 zsoFeet ~--------------~ 

FIGURE 183.-Section northwest of Shinnecock Canal. a, Hempstead gravel member; b, Montauk till member (very clayey). 

-- -.----:.-.. :-----=--=--: ............. 

·- ·----... ---- ------~ 

c 

~~--.~~--=.;;~ .... ~i::.~~=;~~~~:.~~~:,:.~ ~~ ~ ~0·~~"-: 0 ·z.sFeet 

FIGURE 184 . ...:..Section on Jessup Neck, west of Sag Harbor. 

a, Dune sand; b, Wisconsin till; c, Hempstead gravel 

member; d, unconformity; e, Montauk till member. 

On Jessup Neck there are many exposures of gravel, most of them only slightly disturbed. 

In only one place, however, near the north end of the bluffs on the west side, are the relations 

o~ the deposit ciearly seen. At this point the gravel is a well-developed horizontal bed resting unconformably upon the Montauk member with the relations shown in :figure 184. Another 

exposure near the. same point was of interest in showing an ea~ly stage of a flexure such as has 

given rise to 1nany faults on the island (fig. 185). From Jessup Neck to Sag Harbor there are 

no good exposures. 

• 

• 

• 

• 
MANHASSET FORMATION-HEMPSTEAD GRAVEL ME~BER. 155 

Hog· Greek Point.-So'uth of Lion Ilead Rock, near Hog Creek Point, gravels belonging 

to the upper part of the :Manhasset formation were seen in strong development above the 

Montauk till member (figs. 153 and 154, pp. 142 and 143), and just north of Fireplace an 

exposure showed a marked unconformit:y in the , 

~----~~ :Montauk till member near Cedar Point, a few 0 · FIGURE 185.-Soctio!l on Jessup Neck, west of Sag Harbor, showmiles west (fig. 121, p. 128) and above the uncon- ing fold changing downward into fault. 

formity shown in figure 123 (p. 128). 

Montauk peninsula.-Farther east the next point at which th.e gravels were seen was half 

a mile west of Rocky Point, on Fort Pond Bay, where the conditions shown in figure 155 (p. 143) 

were observed. The gravels here (upper part of Manhasset formation) are strongly folded. At 

Culloden Point, sands belonging to the upper part 

of the :Manhasset forma-

. tion, were seen resting upon 

and apparently infolded 

. with the Montauk till member, as brought out in figure 

187. Near Shagwong Point 

FIGURl~ 186.-Section near Fireplace, South Fluke, showing unconformity in gravels, presumably the section of gravels (beHempstead and Herod gravel members. longing to the upper :Man0 . so roo Feet 

hasset) shown in figure 188, was exposed. A persistent bed of chocolate-brown clay (upper 

}.1anha~set n, 3 to 4 feet thick, was also seen near this locality above 10 feet of the Montauk till 

member and 1 to 3 feet of later drift. 

ci ...__ ____ __. So.Feet 

· Just north of Montauk Light 

occur several fine exposures of 

folded and overturned sands and 

gravels. They clearly lie above 

the Montauk till member, which 

rises from beneath them near the 

FIGURE 187.-Section near Culloden Point, Montauk. a, 1" h h b · · "bl h Wisconsin till; b, sand with reddish clay laminm (either 1g t OUSe, 'tlt lt lS poSSl e t at 

Hempstead gravel member or gravel phase of Montauk they represent the gravelly phase 

tillmomber);_c,Montauktillmember. of the Montauk member. The 

conditions are illustrated in figure 174 (p. 151). 

Opposite the lighthouse and at the point a considerable thickness 

of sands and gravels which unquestionably belong to the Hempstead 

....._ ___ ~___, 1oofeet 

FIGURE 188.-Soction 1 milo west of False Point, Montauk. a, Till (Mon- tauk till member); b, cemented ferruginous sand and gravel with some 

bowlders (Montauk till member?); c, .sand belonging to Hempstead gravel member; d, gravel belonging to Hempstead gravel member. 

member lies above the 

Montauk member. 

Figure 158 (p. 143). 

shows the occurrence 

of possible Hempstead 

material in the bluffs 

and at the same tin1e 

indicates the puzzling 

complexity of the ex0 zoFe~.t '-----~ 

FIGURE 189.-Section south of 

Montauk Light. a, Montauk till member; b, cross- . bedded sands belonging to 

Hempstead gravel member; c, alternating sand and clayey sands belonging. to Hemp- stead gravel member; d, 

sand and gravel of normal 

Hempstead member. 

posures. The section between the small bay south of the lighthouse and the point is shown 

in figure 159 (p. 144). Figure 189 shows the profile at the extreme point. 

In the 2-mile stretch of beach southwest of Montauk Point no good exposures of the gravel 

were observed. Just north of tlie bend of the shore from southwest to west, however, gravels 
156 GEOLOGY OF LONG ISLAND. 

belonging to the upper part of the Manhasset formation were seen above the :Montauk till 

member for a d~stance of nearly a quarter of a mile. The general attitude of the beds is horizontal, but they are 

locally disturbed and 

folded (fig. 190). In 

the bluffs half a mile 

east of Ditch Plain 

gravels were noted rest- FIGURE 190.-Section 2! miles east of Ditch Plain, Montauk, showing Hempstead gravel member over- _ ing on the Montauk 

lying Montauk till member. 

member and apparently 

cut by an exteU:sive thrust fault. The conditions are represeJ?-ted in figure 191. Near the 

beginning of the bluff west of Ditch 

Plain the somewhat complicated occurrence of gravel represented in figure 

192 was observed. 

In the bluffs of the south shore 

west of Fort Pond traces of the 

. Hempstead gravel member are seen 

here and there near the top. One of 

FIGURE 191.-Section half a mile east of Ditch Plain, Montauk, showing folded 

and faulted gravels overlying Montauk till member. 

the best sections measured was at a point about a mile from the west end of the bluffs. 

as follows: 

Bluff section near "First House," Montauk. 

Feet. 

Recent: Dune sand ................................................ -....... . . . . . . . . . . . . . . . . 5 

Wisconsin: Gray to buff bowlder till........... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 

Hempstead gravel member or Montauk till member: Buff sand and gravel with basallaY,ers 

cemented by iron· .................................. " . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 

Montauk till member: 

Sand phase (irregularly s~ratified sand alternating with thin clay laminre) ................. _ 20 

Till phase (banded drift and talus).............................. .. . . . . . . . . .. .. . . . . . . . . . . 30 

It is 

Adjacen,t islands.-The conditions on the smaller islands adjacent to Long Island at· the 

east end are very similar to those on the North and South flukes. Thin beds of sand or gravel 

are seen in places above the ~1ontauk member o:q. Plun1 Island (b, fig. 171, p. 146) and on Gardiners Island (d, fig. 167, p. 146), but except on Robins Island no noteworthy developments of 

the gravel were observed. 

-~~:-_-~· f~::!~~-=--·--- On Robin~d Isl~~d, how- ~);·,C?.-~.-~t:";~.o~'~= ----=~ ever,acons1 era ebodyof ~~~~~~~~~~~~~~~~~~~~~~~~~~~ theHemp~eadgravclmemo 100 zooFeet .___ ____ __......__ ____ _, her was noted above the 

FIGURE 192.-Section west of Ditch Plain, Montauk, showing apparent unconformity between till. Figure 165 (p. 145) 

cross-bedded gravel (Hempstead gravel member) and underlying banded till (Montauk till 

member). shows disturbed Hempstead gravel resting upon an irregular surface of the ~1ontauk member on the east side of the 

island; figure 193 shows a slight thickness of presumably Hempstead gravel member above nn 

unconformity on the west side of the island; and figure 194 shows a greater thickness in unconformable contact with 

older gravels supposed 

to belong to the Herod 

gravel member. 

d J 0 too Feet ~------------~~--~ 

FIGURE 193 . .,-Section on west side of Robins Island. a, Hempstead gravel member; b, unconformity 

marked by layer of ferruginous cemented gravel; c, sand, gravel, and clay (Jacob sand); d, dark-gray, 

green, and purplish clay (Gardiners clay). . 

Deposits penetrated 

by wells.-The Hempstead gravel me~ber is 

.penetrated by a·large number of wells in the western and central parts of Long Island, practicallyevery well that has entered the ~1ontauk till member (see table, p. 148) having first passed 

• 

• 

• 

• 

• 

• 
• 

VINEYARD FORMATION. 157 

through the Hempstead. In wells it is usually very difficult if not impossible to distinguish the 

member from the overlying Wisconsin drift, and this differentiation 'has not in general been 

attempted in the following table, which gives a few of the more definite occurrences: 

Hempst13ad gravel member of Manhasset/ormation in wells of Long Island. 

i 

No.a Locality. Owner or place. Depth of for- Character of materials. 

I 

Name used in original rnation.· reports. 

Feet. 

23 Brooklyn ............. Eighth Avenue and Eight- 15-35 Silty to clean sand and graYel ......... Wisconsin. 

centh Street. 

37 ..... do ••••••.......... Bartlett Street and Harri- 60-65 Coarse sand ....... : ......... ~ ......... Tisbury. son Avenue. 

141 East New York ....... Brooklyn test well No.5 .... b 16-192 Reddish-brown granitic gravel. ....... Wisconsin. 200 Jamaica South ........ Baisley pumping station .... 21-58 Fine to coarse yellow sand ............ Wisconsin and Tisbury. 3.~7 Port Washington ...... T. Valentine ................ 15-53 ~?~~~~~~~~-~~~1-~~-~~~~--:: ::::::::::: Transition and Tisbury. 

366 .. , .. do ................ Dodge estate ................ 6-16 Tisbury. · 373 Long Beach ........... Long Beach Association ..... 40-76 Gray to yellow sand and gravel ....... '!'is bury and Sankaty. 

a Numbers refer to well records in Prof. Paper U.S. Geol. Survey No. 44. bIn part. 

Of t~e wells included in the table complete records are giyen of No .. 366 on p·age 113 and 

No. 373 on page 73. 

AGE. 

The I-Iempstead gravel me1nber is a re.treatal deposit of the ice sheet which at its farthest 

adYance 'laid down the Montauk till member. As has been indicated elsewhere, the ice 

lingered in t4e eastern part of the island 

to the close of :Manhasset deposition, the 

last important incident of its occupation being a vigorous readvance which 

scoured and disturbed the older beds at 

a time when it had withdrawn from the 

west end of the island, permitting the 

accumulation of the outwash deposits 

represented by the I-Iempstead member, 

0 100Feet 

FIGURE 194.-Section on west side of Rohins Island. a, Hempstead gravel member; b, brownish loamy zone along unconformity; c, Herod gravel member. 

which is thus contemporaneous with the last part of the :Manhasset invasion and is to be placed 

in the Illinoian. , 

VINEYARD FORMATION. 

Between the base of the Recent beach deposits, which probably do not extend more than 

20 or 25 feet below sea level, and the horizon at which the Gardiners or the Jacob fauna is to 

be expected, peat, marsh n1uck, wood, st~mps, and tree trunks, also quahog, clarn, scallop, 

and oyster shells have been found. The finding of so many of these remains in deposits that 

seem to be above the Gardiners clay and the Jacob sand ·and below the Wisconsin and Recent 

accumulations seems to point to an intervening formation of intermediate age. As it is unlikely 

that they belong to the glacial Manhasset formation it seems probable that they should be 

referred to the Vineyard 1 interglacial stage, representing marsh, soil, and beach deposits formed 

at a time when the land stood considerably above its present position with reference to sea level. ' 

In the following table is presented a lis_t of occurrences of shells, wood, peat, etc., which 

seem likely to have come from this formation. The occurrences are largely taken from the 

reports of A. C. Veatch 2 and F. J. H. Merrill, 3 but the present writer alone is responsible for 

the interpretations. 

I Woodworth, J. B., Seventeenth Ann. Rcpt. U.S. Geol. Survey, pt. 1, 1896, p. 979. 

s Prof. Paper U.S. Geo!. Survey No. 44, 1906, ~ell records. 

· a Annals New York Acad. Sci., vol. 3, 1886, p. 357. 
158 GEOLOGY OF LONG ISLAND. 

Wells reporting possible occurrences of the Vineyard formation. 

No. of 

Location. well Depth. Material. 

(Veatch). 

Fort Greene ( 1814) ..................... . Fort Lafayette................ 2 

2 

Governors Island. . . . . . . . . . . . . 10 

Brooklyn, 556 K_ent 'A venue... 55 

Long lsl!.!nd City, 408 Ninth 118 

Avenue. 

Brooklyn test well No. 3. . . . . . 204 

Brooklyn test well No.8...... 205 

New Utrecht .................. ---------- Flatbush Almshouse ................... . •Between Brooklyn and Flat- ......... . lands. 

Bushwick .............................. . East New York ........................ . Hicksville..................... 502 

Quogue ............... __ . __ . .. 859 

BridgAhampton. . . . . . . . . . . . . . . 897 

Fat. 

70 Clam shells. 

23-40 Gravel and sand with broken shells (possibly Wisconsin drift with secondary fossils). 

40-53 Compact silts with many shells including Nassa obsoleta, Anomia ephippium, .Mya arenaria, 

Crepidulafornicata, Mytilus edulis. 

70 Dark gravel with shells (under tillr. , 129 Oyster shells (these occur below a thick clay and may belong to the Gardiners clay). 

50-57 Quicksand with marine shells (under till). 

72 Peat (in yellow sand above Gardiners clay). 59-72 Water-rolled twigs (in gray sand above Gardiners clay). 

43-67 Pyrula, clam, oyster. 

40-50 Clams and oysters. 60 Exogyra costata: 

40 Log of wood. 

80 Clam shells. 

15-22 Black silts, etc.,- resembling soil zone (beneath outwash). 

135 Mulinia, Astarte1 Nassa trivittata, and fragments of echinoderms (horizon doubtful). 

100 Shell fragments m sand and gravel. 

WISCONSIN DRIFT. 

The term Wisconsin is applied to the deposits laid down during the last glacial advance as 

a mantle over the older deposits of Long Island, the application of the term to this region being 

based on the tracing of the deposits by T. C. Chamberlin/ G. F. Wright/ .and others across New 

Jersey, Pennsylvania, New York, Ohio, Indiana, and Illinois, into the type area in Wisconsin, 

from which the name was derived. As it is a surface formation, much more is known of its 

character, distribution, and manner of accumulation than of the features of the older drifts, 

and its deposits may with advantage be differentiated into a number of component parts, 

the most important of which on Long Island are (I) the till sheet or ground moraine, (2) the 

outer or Ronkonkoma moraine, (3) the outwash from ice along the Ronkonkoma moraine, 

(4) the later (inner) or I-Iarbor I-Iill moraine, .(5) the outwash from ice along the Harbor Hill 

moraine, and (6) the retreatal deposits. 

THE TILL SHEET. 

CHARACTER. 

The till sheet or ground moraine includes the deposits laid dow-n beneath the glacier when 

the debris contained in the base of the ice sheet or dragged along beneath it was set free, either 

through melting of the ice or by friction with the overridden surface. It is composed of unassorted mixtures of clay, sand, and bowlders, the nature of which differs greatly in different parts 

of the island. In western Long Island granitic material commonly constitutes- 5 to 10 per 

cent of the pebbles, though in some localities nearly half of the pebbles are granitic. In other 

places, however, quartz pebbles predominate, it being in fact almost impos~ible to find granitic 

materials in some of the outcrops. Toward the central part of the island, beyond the Cretaceous 

and Mannetto remnants of Eaton Neck, the percentage of quartz rapidly decreases and that of 

granitic pebbles and bowlders increases. In the eastern portion of the island pebbles and 

bowlders of the granite type usually predominate in the till. In general it may be said that 

the till varies in composition with the character of the underlying materials over which the ice 

had recently passed. This explains the quartzose character Qf the till in the vicinity of the 

Cretaceous deposits and the Mannetto gravel, the gravelly -or sandy character over the Herod 

gravel member of the }.1anhasset formation, and the more clayey character and local red coloration that it has where resting upon portions of the Montauk till member of the Manhasset formation containing Triassic material. At several points, especially on Jessup Neck west of Sag 

Harbor and on Montauk Point, the till appears to have been formed locally of reworked sand 

dunes, and it is not improbable that many of the sandy phases of the north shore are of similar 

origin. 

1 Third Ann. Rept. U. S. Geol. Survey, 1S83, pp. 291-402. 2 Bull. U.S. Geol. Survey No. 58, 1890, pp. 39-110. 

• 

• 
WISCONSIN DRIFT. 159 

The till has yielded fossils at a considerable number of points. The greater number 

evidently represent material reworked from the Gardiners clay, the Jacob sand, or the Vineyard formation, but many silicified fossils from the limestones of the mainland occur, and here 

and there a Triassic sandstone with leaf impres~ions is found. 1 

In color the till, where unoxidized, is usually a dull gray, with a slight tinge of buff or· brown 

due to the oxidized materials incorporated in the mass. Iu western Long Island, however, it 

commonly exhibits a distinct reddish tinge, due to the presence of Triassic material. This 

coloration is noted in only a few places east of Little Neck Bay, Flushing, although traces are 

observed where the Wisconsin overlies the reddish phase of the Montauk till member of the 

:Manhasset. 

The thickness of the Wisconsin till is greatest in western Long Island, where it is commonly 

10 to 15 feet thick, and in some places, where it is represented largely or entirely by slightly 

shoved or reworked portions of the underlying gravel, much thicker. It seems to become 

thinner toward the east, the bluff sections· of the central part of the island· commonly showing 

not more than 5 to 10 feet, and those of the extreme eastern parts usually less than 5 feet. 

In structure the till is usually rather loose, it~ materials showing a general lack of coherency. 

For this reason exposures do not stand well as a rule and soon become covered with talus. 

Relatively little clay is present in the till. In this respect it differs very noticeably from the 

Montauk till member, which is not.only associated with clayey beds in many places, but carries a 

sufficient amount of clay throughout its mass to act as a binder, thus. making possible the cementation observed in it. 

In texture the Wisconsin till is very divers~, all grades of coarseness from sand to bowlders 

being known. On the whole, however, it tends to be somewhat coarse, resembling the surface 

till of New England rather than the more compact till of the Montauk member. Bowlders are 

not very conspicuous in western Long Island, being in few places as large or as closely packed 

as in some areas of the :Montauk till member, such as the bowlder bed of. I-lempstead Harbor. 

In fact large bowlders are of comparatively uncommon occurrence in the general till sheet 

mantling the Manhasset terrace, though they are abundant in the moraine to the south. 

In general there are no indications of banding in the Wisconsin till, but a few exposures 

were seen in which a lamination similar to that of the l\1ontauk member was noted. All such 

exposures were of very small extent and were clearly the result of local rather than of general 

conditions. They are confined mainly to the sandy phases of the till, being almost nowhere 

present in the coarser varieties (Pl. XXIV, B). 

Where the iWisconsin till is less than 4 feet thick, it has commonly been oxidized from top· 

to bottom and exhibits brownish or yellowish colors such as characterize the drifts of New 

York and New England. Where the till is thicker, the oxidation p1ay fail to reach the bottom, 

the lower part being of a lighter and more grayish color. In most places where the till is 10 

feet or more thick, however, it has a slight buff tinge throughout, due to the fact that a ~onsiderable portion of its material was oxidized before being incorporated into the glacier that 

later deposited it. Presumably if the invasion had been longer continued, the later till derived 

from less-weathered ~:materials would have been as dark and unoxidized as that of the Montauk 

till member. SOURCE OF MATERIAL. 

The materials of the Wisconsin till are derived from the formations over which the ice 

passed, the larger portion of the deposits coming from the older unconsolidated gravels, sands, 

and clays of the immediate vicinity. This is especially true of the region from Flushing to 

Port Jefferson, where not only the great abundance of loose material but also the character of 

the topography favored the absorption of large amounts of material by the ice. Farther east 

the percentage of material derived from near-by deposits seems to have been less, the Sound 

affording unfavorable conditions for absorption. A considerable quantity of the coarser 

mat·m~ial, mcluding the bowlders, is de~ived almost entirely from the mainland, as are the granite 

1 Newberry, J. S., Proo. New York Lyceum Nat. Hist., 1st ser., 18il, pp. 149-150. 
160 GEOLOGY OF LONG ISLAND. 

pebbles except those derived from the Manhasset formation or older gravels. It is noticeable 

that Triassic fragments, which are common in the Montauk member, are relatively rare in the 

Wisconsin, except at the extreme west end of ~he island, apparently indicating that the Wisconsin invasion was weaker or less prolonged than the earlier Montauk invasion. 

RELATIONS AND STRUCTURE. 

The relation of the Wisconsin till to the older deposits is very simple. It is a superficial 

mantle resting upon the eroded surface of the older deposits and following closely the contour 

of the erosion surface, rising in the hills and sinking in the valleys. Where the surfaces on 

which it was laid down were even its thickness was commonly only a few feet, but in the 

valleys it was not infrequently deposited to a greater depth. Over one large area, including 

the greater part of .the Nissequogue dr.ainage system, the drift is so thin as to be unrecognizable. 

The Wisconsin till in general does not itself show any indications of disturbance other 

than by landslides along the present bluffs. Folding and faulting, such as characterize the 

older formations, are generally absent, apparently indicating a very weak ice sheet compared 

to the Montauk. · · 

The base is in many places sharply defined, especially where the Wisconsin till rests upon 

.the Montauk till member, knife-edge contacts being common (Pl. XXII, A, p. 136). In other 

places, however, there is more or less transition between the underlying gravel and the till, as 

if parts of the gravel had been dragged along, reworked, and incorporated into the till. There 

are also ~any local examples of contortion and folding on a small scale (Pl. XIX, .A, p. 114), 

although nothing comparable with the folding during the Montauk substage was observed. 

DISTRIBUTION. 

Greater New York.-West of the eastern limit of Greater New York, near Little Neck Bay, 

the Wisconsin till is relatively thick, covering the greater part of the surface with a mantle 

effectually hiding. the underlying Manhasset formation. Exposures showing 15 or 20 .feet of 

till are not uncommon,· and even thicker sections are found at many points in the vicinity of 

Brooklyn and: Long Island City. In fact, the general till sheet seems in this region to grade 

almost insensibly into the thick t\]l of the moraine. The material is a rather tough l?owlder 

clay apparently consisting largely of Triassic ingredients brought from the New Jersey side of 

the Hudson, 5 miles to the northwest. Both the composition and the unusual thickness are 

largely explained by the proximity to the outcrops at this point. The Ronkonkoma ridge, 

now crossed by the Harbor Hill moraine just south of the head of Manhasset Bay, originally 

extended across this region but was overridden and reworked at a later stage by the ice, and 

much of its material was in~orporated in the Wisconsin till sheet. " . 

A detailed investigation of the geology of this part of the island, which it did not appear 

desirable to duplicate in the field work for the presen~ report, had been made by R. D. Salisbury 

and others 1 several years before, at a time when the Montauk till member had not been recognized as a. separate division and all till was included in the Wisconsin. The writer had no 

opportunity for reexamining the region in detail, but from what he has seen he is inclined to 

regard the Wisconsin till, although undoubtedly of considerable thickness, as forming only a 

part of the till exposed, the lower and probably thicker portions seemingly belonging to the 

Montauk till member of the Manhasset, correlated with the illinoian. The fact that the Illinoian 

is the principal till wherever found in New England and in the Ohio and Mississippi valleys, the 

Wisconsin being almost everywhere relatively thin, makes it seem improbable that the conditions at the point under discussion are exactly reversed, especially as the Wisconsin constitutes 

hardly more than a mantle in adjacent regions. The depth of oxidation, which is in not a 

few places 10 to 15 feet or more, is perhaps the mostsatisfactory of the direct evidences of the 

presence of older drift, being much in excess of' th,e 5 feet commo~y reached by the Wisconsin 

we a the ring. · 

1 New York City folio (No. 83), Geol. Atlas U.S., U.S. Geol. Survey, 1902. 

• 

• 

• 

• 
• 

WISCONSIN DRIFT. 161 

. In the- vicinity of Astoria and between Little Neck and Flushing bays, according to R. D. 

Salisbury 1

-

The hillocks of ground moraine [till sheet of this report] occasionally assume an elliptical form, about twice as long 

as broad, the longer axes being parallel to the direction of ice n;tovement. Such hills ·of ground moraine are called 

drumlins. One of the best examples of a drumlin in this region is the hill at Lawrence Point. Other examples of 

drumlins, or of drumloicl hills, occur three-fourths of a mile farther south, half a mile northwest of Steinway, and north 

of College Point, where Tallman Island appears to be a drumlin. The elongate hill just southwest of Tallman Island 

also has something of the _drumloid form. 

Little Neck Bay to Oyster Bay.-Between Little Neck and Oyster bays, where the Wisconsin drift is seen in its most characteristic development, the till is gravelly, including large amounts 

of stained and white quartz pebbles from the underlying Cretaceous beds and the Mannetto 

gravel. It overlies the eroded Manhasset surface as a mantle or veneer, having a maximum 

thickness of about 15 feet but averaging considerably less. Even shallow roadside sections 

may cut entirely through the covering into the Manhasset below. Although the surface as a 

whole maintains the flatness characteristic of the Manhasset terrace, it shows in many places 

a subdued morainal aspect, due in part to the unequal deposition of the till and in part to a 

disturbance of the gravel of the Manhasset formation by ice drag or shove. As would naturally be expected, all gradations between slightly disturbed Manha$set material and thoroughly 

reworked gra:vels are found. Bowlders are not, as a rule,· either numerous or large in the till 

sheet of this region, althoug4 blocks of considerable size are seen here and ther~. The till 

sheet follows the contour of the Manhasset surface rather closely, but its .thickness is more 

variable in the valleys than on the terrace surface. In many of the smaller valleys the till 

filling is considerable, but in the large depresN, s.. sions now occupied by the harbors and bays of --' ... ,, 0 ' ... - . the north shore the amount of till is ordinarily 

'rather slight, apparently because of a concentration of ice activity causing a tendency to 

erode rather than deposit at those localities. . 

.,_., .. :.:_·~::-=~=;..:.:_~:_=:_:_"i: -;~-=-~~-:_~~ ~~-~~~ Oyster Bay to Port Je.fferson.-The distribution and character of the Wisconsin till between 

FIGURE 195.-Sectlon showing till.rldge at head of valleys opening to Oyster Bay and Port Jefferson is very similar 

the north. 

to that in the district immediately west. Its 

thickness, however, is son1ewhat less, and it is in general somewh.at more gravelly and carries 

fewer bowlders. One very large bowlder, however, measuring nearly 40 feet on its longest 

diameter, was seen on the ro.ad between Port Jefferson village and the railroad depot. Because 

of the occurrence of the Montauk till member at the surface at many points it is difficult, at 

some places wher~ the exposures are poor, to tell whether the till is Montauk or Wisconsin, 

but where the exposures are good there is usually little difficulty. The contact, where the 

older and younger tills come together, is usually very sharp. 

A notable feature in this region is the thickening of the drift into a sort of miniature 1noraine 

at the head of a number of the north-south valleys, as indicated in figure 195, apparently caused 

by the shove or drag of the ice masses passing up the valleys. · 

Gold Spring Harbor region.-The Wisconsin till sheet undoubtedly extends beneath the 

I-Iarbor Hill moraine and the outwash associated with it, reaching at least as far south as the 

Ronkonkoma moraine, but because of the thickness of the overlying deposits it is rarely seen. 

· I-Iere and there, however, where a pre-Wisconsin valley of considerable extent stretched back 

above the inner moraine, as south of Cold Spring Harbor, residual ice seems to have prevente~ 

the covering of the region by outwash, and a coating of Wisconsin till was left at the surface 

on the sides of the old valley. This is made manifest largely by bowlders, although outcrops 

of the till are not wanting. It is probable, however, that some of the bowlders came from 

the Montauk member of the Manhasset formation, which presumably outcrops around the 

border of the valley. 

1 Op. cit., p. 14. 

1629°-14-12 
• 

162 GEOLOGY OF LONG ISLAND. 

Dix 1-Iills.-The Wisconsin till is best seen where outliers of older formations rise above 

the outwash, as in the region north of the Dix Hills, where not only bowlders but also good 

exposures of till are seen overlying the older deposits. Plate XXIV, B (p. 162), shows an outcrop of banded Wisconsin till resting upon an older and somewhat disturbed gravel, apparently 

the Mannetto gravel. · 

Smithtown "driftless area. "-The Smithtown "driftless area,,. which is driftless only in 

lacking conspicuous Wisconsin deposits, is one of the most remarkable regions of the island. 

A line extending along the south base of the Harbor Hill moraine from Nissequogue River westward to Kings Park, thence southward to the Ronkonkoma moraine, thence eastward within 

a mile or two of I-Iauppauge,,and finally northward through Smithtown to the point of beginning, 

would inclose an area of nearly 15 square miles, comprising the western part of the drainage 

basin of Nissequogue River (Pl. X, p. 46), in which no recognizable Wisconsin till occurs. 

At first sight its absence might seem· to be due to post-Wisconsin erosion, but that such 

a drainage system, the most advanced of· all on the island, could have been developed 

here while practically nothing was being accomplished in post-Wisconsin time in other situations equally favorable to erosion is manifestly unlikely. The discovery of a Wisconsin esker 

three-fourths of a mile below Smithtown,.extending to the very bottom of the present valley, 

fully established the pre-Wisconsin origin· of the drainage system. That the ice passed over 

the region is conclusively shown by the presence of the well-developed moraine on the south 

rising from 40 to 100 feet or more above the Manhasset level. . How, then, is the absence of 

drift to be explained~ To the writer the most probable assumption seems to be that the district was covered with a thick mantle of sno~ o;r snow ice previous to the advance of the glacier, which on invading the region overrode the surface deposits without coming into contact 

with them. This would explain the absence of disturbance by shove, the lack of gravelly till 

accumulations such as are usually very conspicuous where the Manhasset formation has been 

overridden by the Wisconsin ice, and the almost perfect preservation of even the minor drainage features. Under this assumption the only drift to be looked for would be the englacial 

material set free on the final melting and retreat of the ice. The absence of bowlders in the 

region indicates that if present the englacial material must have been scanty· and very fine 

grained. That su~h material may mdeed hav·e been set free is not improbable, but because of 

its similarity to the Manhasset deposits it has not been recognized. No coarse materials or 

in fact anything clearly identifiable as Wisconsin drift was seen anywhere in the western half 

of this drainage system. 

Middle Island region.-Stretching from Coram northeastward to Long Pond, about 2 

miles south of Wading River station, and thence southward to the· Ronkonkoma moraine is a 

broad terrace-like tract of high land (apparently Manhasset formation), which stands above the 

· outwash level and is more or less cut by pre-Wisc<;>nsin drainage lines (Pl. XX, p. 116), the 

whole clearly resembling the Manhasset terraces near Hempstead Harbor and elsewhere along 

the north shore. The surface is likewise characterized by a subdued morainal topography, 

apparently due to the drag or shove of the. loose gravels by the Wisconsin ice, and is covered 

with more or less scattered bowlders, mostly small,· and with patches of Wisconsin till. This is 

the largest single area of conspicuous intermorainal Wisconsin drift on .the island. 

· Peconic·River region.-The region along Peconic River between the two moraines (Pl. IX, 

0, p. 42) ·shows a fair number of bc;>wlders and here and ·there a small mass of Wisconsin till, 

but the greater part of the region is made up of an undifferentiated mixture of Wisconsin outwash and gravel of the Manhasset formation. It is on the projecting Manhasset surfaces that 

the bowlders and patches of till are most likely to be found. .. . 

Riverhead to Orf,ent Point.-The till south of the Harbor Hill moraine on the North Fluke 

is very thin, and through. considerable stretches it is impossible to recognize the drift in sections. Its presence is made manifest, however, by a bowlder here and there and by irregularities of the surface due to ice shove. 

Adjacent islands and the South Fluke.-The conditions on the adjacent islands-Robins, 

Shelter, and Gardiners-are not notably different from those on theN orth Fluke, although their 

• 

• 

• 

• 
• 

U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 82 PLATE XXIV 

A. TYPICAL BOWLDER BEACH ON NORTH FLUKE. 

11. BANDED WISCONSIN TILL ON OLD GRAVELS <MANNETTO?), DIX HILLS. 
.. 

WISCONSIN DRIFT. 163 <l ' ' 

more rugged topography seems to have encouraged a more extensive· reworking of the deposits 

, by the Wisconsin ice and a greater deposition of till. 

On the north side of the South Fluke essentially the same conditions prevail as on the islands. 

The till is mostly local and carries relatively few bowlders. On, Jessup Neck and at places on 

Montauk the till seems to be composed largely of reworked pre-Wisconsin sand dunes. 

South of the Ronkonkoma moraine.-There is no decisive evidence that the Wisconsin ice 

ever passed south of the line of the Ronkonkoma moraine in western Long Island. A numbe~ 

of granite fragments, the largest a foot in diameter, were noted ·over the surface of the Half 

I-Iollow IIills and a few still larger bowlders were seen in some of the hollows, but they are 

believed to belong to th'e Montauk till member of the Manhasset formation rather than to the 

. Wisconsin. No unquestionabl~ till was observed nor were any irregularities due to ice drag 

or shove, such as characterize the :Manhasset surfaces north of. the moraine, seen in this region, 

the disturbed condition of the Cretaceous beds of the clay pits being ascribed to creep. If the 

ice ever _covered the region, its presence was but temporary, and it receded without leaving any 

lasting traces. The only clear evidence of till beneath the outwash on the South Fluke is in the 

vicinity of Easthampton, where in times past bowlders have been washed out from beneath the 

sands by the waves. This material is thought to be Montauk rather than ·wisconsin, but- it .is 

not impossible that an extensive thqugh very attenuated sheet of Wisconsin drift may exist 

beneath the outwash east of the Shinnecock Hills. The occurrence of numerous kettles ill the 

outwash 1 (seep. 168) probably indicates the presence of ice south of the moraine, but whether 

these hollows represent ice blocks left after an invasion of the Wisconsin glac.ier or simply extraglacinl snow or s_now-ice accumulations is not known. 

RONKONKOMA MORAINE. 

NAME. 

To the outer moraine, which extends from the point where it emerges from beneath ·the 

later Harbor IIill moraine, near Lake Success, south of the head of Manhasset Bay, eastward to 

:Montauk Point, the name Ronkonkoma is applied,. from Lake Ronkonkoma, not far from the 

center of the island, and one of its best-~own features. · 

CHARACTER, OF. MATERIAL. 

The Ronkonkoma moraine exhibits marked variations in character in its different parts, 

ranging from almost pure till to fine sands. In· a given area, however, its character is fairly 

uniform. The till phase is most largely developed in western Long Island, where certain sec-

'tions reveal many feet of this material. Even here, however, the till is likely to alternate with 

gravels, indicating water action. In the western part of the island the·gravels are commonly 

very coarse, with only faint traces of banding, and resemble the tumultuous esker deposits of 

~ew England and elsewhere. Finer sands and gravels, some of them distinctly stratified, are 

present in places. · 

Farther east, in the region of the West or Mannetto Hills, the gravelly phase becomes more 

pronounced. The greater part of the deposits observed are of coarse, almost structureless 

gravels, but till or similar impervious material appears to be present in considerable amounts, 

as indicated by the numerous springs, kettle lakes, and similar 'features. The stratified gravels 

occur in increased quantities. 

East of the D.L~ I-Iills the material is finer, gravel and sand being here the predominant 

constit~ents of the moraine. Indeed, in places the moraine seems to consist almost entirely 

of sand, especially in the region near New Village and Selden, south of Port Jefferson, and at 

points between Manorville and Riverhead. 

Bowlders are much less numerous and decidedly smaller in the Ronkonkoma moraine than 

in the inner moraine. Few are more than 5 feet in diameter and those exceeding 10 feet are 

exceptional. Notwithstanding this, one of the largest bowlders on the island, said to have 

measured originally 125 feet in circumference, was found in this moraine, at Rock I-Iill, 2 miles 

north of Eastport. 2 

1 Mather, W. W. GeologY. of New York pt. 1, 1843, p. 165. . · 2J3ryson,John, Rock Hill, Long Island, N.Y.: Am. Geologist, vol. 16, 1895, pp. 228-233. 
164 GEOLOGY OF LONG ISLAND. 

• 

The weathering is mainly superficial, like that of the till sheet, and is rare, except on the 

included pebbles derived from older deposits. The only cementation occurs in the neighborhood 

of basic pebbles or s.imilar sources of iron. 

SOURCE OF MATERIAL. 

In composition the moraine partakes less of the character of the local material over which 

the .ice passed than the till sheet, owing apparently to the fact that much of the moraine was 

formed from material that lay high up in the ice, whereas the till sheet was built up from basal 

materials. During the time required for materials to work upward to a considerable height 

within the ice the glacier travels far, hence the morainal material was probably derived from a 

more remote point than that of the till sheet. . 

The granites, which abound in the moraines, are clearly derived from the New York or 

Connecticut mainland, although possibly in part reworked from the underlymg drifts. The 

fact that the proportion of granitic pebbles and bowlders is greater in the mor3:ine than in the 

drifts mentioned would seem to indicate that they were derived to a large extent directly from 

the mainland. There is, however, in the moraine of western Long Island a notaole percentage of 

stained quartz pebbles which must have been derived largely from the Mannetto gravel of adjacent regions, and it is probable that in the sandy district~ farther east a still larger part of the 

morainal material was obtained from adjacent beds of the Manhasset formation over which the 

ice passed. Very little Triassic material occurs in the Ronkonkoma moraine although, as previously seen, it is a large constituent of the older drifts. 

RELA'.riONS TO OLDER DEPOSITS. 

The base of the Ronkonkoma moraine rests upon the eroded surface of several older formations. In western Long Island it lies largely upon the Manhasset terrace, in the hills near 

West bury upon the Mannetto gravel, in the Mannetto and Dix hills upon Cretaceous and Mannetto, and in the region east from these hills to Montauk Point upon the Manhasset. Inasmuch 

as the Manhasset rises to 200 or 240 feet above sea level and the Cretaceous in West 1Iiil probably 

to 350 feet, it is clear that in western Long Island but a fraction of the total height of the moraine, whose maximum is about 410 feet, represents true morainal accumulations. Farther 

east, in the Riverhead region, the thickness of the morainal deposits is greater, only about 100 

· feet of a total of 400 feet being represented by the Manhasset. On Mor:t-tauk the morainal 

deposits are again of subordinate importance, forming but a relatively small part of the 150 

feet which measures their altitude. 

DIS'l'RIBUTION. 

, From Lake Success, south of Manhasset Bay, where the ridge emerges from beneath the 

Harbor Hill moraine, to Syosset, the moraine is composed mainly of kamelike accumulations 

of stratified drift and till. It. is here relatively inconspicuous, being at many points cut by deep 

gaps and at others partly buried by the outwash deposits of streams issuing from the ice front 

during the accumulation of the later Harbor Hill moraine. From Syosset to High Hill the topography of the ridge is distinctly morainic, being marked by conspicuous and very irregular kettles and knolls. The high percentage of quartz in the deposits, topographic indications, and 

the evidence of well records all point to the moderate thickness of the morainal material, the 

Mannetto gravel reaching at some places within 20 feet of the surface. 

At High Hill the moraine reaches its highest elevation east of the mountains of New 

Jersey and Pennsylvania, culminating in a sharp knob rising 410 feet above sea level, although 

the body of the moraine reaches only about 350 feet. The percentage of quartz pebbles in 

the knob l?trongly suggests Cretaceous or Mannetto material, but there is an admixture of 

granites to the very crest, indicating that the knob is a part of the moraine, at least superficially. 

In the lower part of the moraine at the same locality granites are very abundant, and quartz 

is present only in small amounts. The Cretaceous and l\fannetto apparently rise to not less 

than 340 feet at this point, judging from the terrace on the south. Just east of High Hill, at 

• 

• 

• 
WISCONSIN DRIFT. 165 

distances of 1 and 1! miles, there are two gaps occupied by outwash of the later stage, and 

another broad gap is found south of Commack. In the intervening aren,s the moraine is rather 

high, standing 100 to 200 feet above the outwash, or 250 to 350 feet above the sea. 

From the Commack Channel to the big channel now occupied by Connetquot Brook, a 

distance of 7 miles, the moraine is, in the main, a well-developed and fairly continuous ridge, 

reaching an altitude of 220 feet; or 100 to 140 feet above the outwash. About 2 miles southwest of I-Tauppauge, however, at the headwaters of Nissequogue River, the moraine subsides 

loeally to or below the level of the outwash plain, forming the most westerly example of what 

may be termed a "depressed moraine." Similar conditions exist in the vicinity of Lake 

Ronkonkoma, where great outwash plains take the place of the ordinary ridge of till or gravel. 

The moraine, however, is in most places represented by low till accumulations reaching slightly 

~tbove the surrounding level, but more especially by the immense kettle plain formed. by the 

deposition of an outwash sheet over great blocks and masses of ice, which, on melting, gave 

rise to the very pronounced kettle topography of the region. Lake Ronkonkoma itself represents a large kettle formed in this manner. 

Southeast of Selden the morainal ridge becomes once more very pronounced, eontinuing 

with a height of'300 feet or so to Coram Hill. In this region very little but fine sand ean be 

seen in erossing the moraine, and in plaees the ·vegetation is very thin and the sand still shifts 

slightly under the action of the wind. Superficially the material is largely dune sand, but 

whether this is simply a mantle over. a moraine of the normal type or whether the moraine is 

unusually sandy and free from gravel at this point is not de:6nitely known. The latter suppo~ 

sition, however, is thought to ·be probable. 

Near Yaphank the moraine is interrupted by the deep ehannel now oeeupied by Carmans 

River, but fron1 this channel to Shinnecock Canal the ridge is in general strongly developed, 

reaching a height of over 300 feet in places, as at Bald Hill, southwest of Riverhead. The 

moraine is not without breaks, however, there being several points in the region south of 

Manorville, southeast of Riverhead, and near Good Ground where gaps of considerable width 

oceur. 

Although some of the breaks in the moraine east of Coram Hill are due to erosion by the 

later outwash streams, more of them have resulted from the nondeposition of morainal materials, 

as in the vicini~y of Lake Ronkonkoma. In such places the deposition by the outwash streams 

was usually much in excess of the morainal aecumulation, with the eonsequence that the outwash 

deposits reach a much greater height than the morainal deposits, the moraine being of the 

depressed type. 

At Rock, 2 miles north of Eastport, remnants of a bowlder said to have originally measured 

over 125 feet in cireumference are to be found. The bowlder, which has been quarried intermittently by the people of the vicinity since the settle~nent of the· island, and is now much 

reduced, is said to be still an imposing obel~sk-like object 50 feet in circumferenee. 1 

At Shinnecock Canal there is a break in the moraine extending practically to sea level, 

but the Slllnnecock Hill~ east of the eanal, though largely composed, as shown by the bluff 

sections, of gravel of the Manhasset formation, nevertheless have a strong superficial morainal 

topography due largely to the disturbance and reworking of the underlying gravel by the 

Montauk ice and rendered especially eonspicuous by the entire absence of trees such as elsewhere usually obscure the contours of the moraine. The irregular hills and steep intervening 

troughs, bnsins, ancll\:ettles are all well shown. It should ~.e noted, however, that less than a 

eentury ago these hills were eoverecl by drifting dunes, to which a part of the surface irregularities 

are clue. 

The moraine in this region, as in that south of Riverhead, is made up of confluent units and. 

is not a simple ridge, the tendency being toward the accumulation of large, high hills, such as 

that north of I-Iampton Park, Southampton, or sharp knobs such as Bald Hill, southwest of 

Riverhead, and the high cone 3 miles southeast of Manorville, nearly 300 feet in altitude. A 

noticeable feature of these hills is that although the morainal topography is highly dev~lop~d 

1 Bryson, John, Rock Hill, Long Island, N.Y.: Am. Geologist, vol. 16, 1895, pp. 228-233. 
• 166 GEOLOGY OF· LONG. ISLAND. 

and is ·.characterized .by numerous knobs and kettles, there- ate in addition many radiating 

trenches apparently due in part -to the action of running water. The forms are thought to be ' 

the result of ·the accumulation of steep detrital cones by overloaded waters issuing high up in 

the ice, 200 t9 .350 feet above sea level, if one may judge by the altitude of the deposits. The 

radiating channels mainly mark the position of the rivulets in the closing stages, although possibly. they are to.a.subordinate extent due to subsequent erosion before the land became covered 

with vegetation. Many of the_ channels have flat bottoms, many. have steep slopes on the 

outside of the swings,.and in some the late erosion is distinguished from the older by a notching 

of the bottom. 

From Shinnecock eastward to Promised Land the moraine is ~gain strongly developed, 

being represented by a ridge rising to an altitude of more than 280 feet, or about 200 feet above 

the outwash plain. There are, however, a number of breaks similar in character and origin 

to those betwe~n Y·aphank and Shinnecock farther west. 

At .Promised Land occurs: the most important break in the moraine found on the island. 

The ridge is l).ere interrupted for more than 4 miles, the intervening space being occupied by a 

sea beach covered with recent dunes. On Montauk the· conditions are similar to those in the 

.Shinnecock: Hills, the, :morainal features being especially conspicuous. because of the absence 

of ·trees. The· morainal development, which seems to 1 be more the result of disturbance and 

remodeling of the· old Manhasset topography than of deposition or other accumulation, 1s on a 

larger scale than in the Shinnecock Hills. Probably not more than 50 of the 150 feet of the elevation, however, is to be referred to the moraines, and it is almost certain that on the outer 

point the thickness of Wisconsin deposits is very much less. 

The Ronkonkoma moraine is supposed to be represented_ farther east by the morainal 

accumulations of Block Island, Marthas ·Vineyard, and Nantucket, but the correlation with 

these deposits is :not absolutely certain, for the reason that the continuation of the Ronkonkoma 

moraine eastward. is below sea level, and, the evidence of connection afforded by the submarine 

bars is not conclusive. · · 

OUTWASH FROM ICE ALONG RONKONKOMA MORAINE. 

OCCURRENCE. 

The outwash from th~ .Ronkonk~ma moraine includes the g~ea~ sloping. phi~s lying south 

of the moraine and. extending continuously, except for the short breaks at the Shinnecock 

Hills, from the west end of the island to the vicinity of Amagansett. It is,well de~eloped aro,uu"d 

L_ake Ron~o:.:koma, alarge kettle lake surrounded by mora~e ~nd outwash~ the centr~l part 

of the island. CHARACTER OF MATERIAL. 

The material of the outwash plain ranges froiD: the moderately coarse gravel with pebbles 

as much as' 2 inches in diameter found along the margin of the moraine to. find sand at the 

south shore. The relative percentage of quartz and granite pebbles varies greatly, all gradations being found from a pure quartz gravel not much different from portions of the Cretaceous 

and Mannetto, except that the staining is less conspicuous, to granitic gravels in which quartz 

pebbles form a very ·small part. In general, as in the older formations, the amount of quartz 

varies with 1he proximity to Cretaceous or Mannetto masses. West of the Dix Hills the percentage of quartz is especially high and in some places a granitic pebble can be found only with 

difficulty. 

Because of the flatness of the deposits sections are extremely rare, but from the few shallow 

excavations it appears that all gradations from nearly horizontal stratification to a highly 

complicated flow and plunge structure 'exist. The materials are in few places weathered or 

stained and are not known to be cemented either by iron oxide or otherwise, even locally. 

Certain parts of the outwash plain have a thin superficial coating of dark-brownish loam, 

consi~ting in some places largely of sand, but in others of pebbles intermixed with a certain 

amount of finer silt. It is this finer material, which is oxidized, that gives the color to the 

• 
WISC9NSIN DRIFT. 167 

deposits. The depth is in .. some places only a few inches and was nowhere seen to exceed 1! 

feet. .No trace of lamination was noted in the deposits seen by the writer. The contact with 

the underlying material is usually sharp, and the material has the aspect of being a separate 

formation, apparently not greatly different from the so-called" Jamesburg loam" of New Jersey. 

The 1naterial is well developed in the Hempstead Plains and is seen near the moraine at points 

north of East Moriches and southeast of Sag Harbor. 

SOURCE OF l\lA'.rJ~RIAL. 

This outwash was, in general, fed by streams issuing at the base of the ice or at least at 

lower points than those forming the Ronkonkoma moraine. The materials, being ·derived 

from portions of the ice near the base, are of more local origin than the higher morainal deposits, 

a fact which would explain the greater percentage of quartz, etc., 'derived from the adjacent 

~reas of Cretaceous and Mannetto. This is especially true of the outwash is~uing through 

gaps in the moraine. The material" from higher portions of the ice, as in the higher outwash 

fans along the base of the moraine, which were evidently supplied from the same sources as the 

moraine itself, is likely to have had a more remote origin, as was explained in the discussion of 

the source of the morainal materials. The diversity in the relative amounts of quar:tz and 

granite pebbles is very great and depends mainly on original differences in supply due .to the 

character of the material over which the ice passed and possibly also to the presence of deposits 

of the Manhasset formation or other gravels in the path of the outfl.owing streams. Such 

deposits are known to have been present in the path of the streams that laid down the later 

outwash from the ice along the Harbor Hill moraine below the Mannetto and I-Ialf Hollow 

hills, where the gravels of the Manhasset formation approached the surfa~e or projected through 

the outwash at many points. · 

RELATIONS TO OLDER DEPOSITS. 

The outwash from the ice along the Ronkonkoma moraine rests upon an old and extensively eroded surface of gravels belonging to the Manhasset formation. This old surface had a 

southward slope s:imilar .to that of the present outwash, although somewhat more gradual. 

Under the action of .long-continued stream work, however, it became trenched by many welldefined and fairly deep southward.,.leading valleys, its edges were indented by marine estuaries, 

and its borders were l9cally cut by low marine cliffs. Near the moraine, where· the outwash deposits were most abundant, and especially where the deposition was effected by small rivulets 

rather than by large ·streams occupying well-defined channels, the older topography has been 

obscured, but farther south the outwash becomes attenuated and the Manhasset shows at the 

surface. In some places, where glacial streams of consiqerable size led through gaps in the moraine, the work ~as at first one of erosion rather than of deposition and channels were cut either 

in the earlier. outwash or in the underlying Manhasset. Such channels may be seen ·extending 

southward across the Manhasset outwash at many points, although they are much smaller than 

those formed at the subsequent Harbor Hill substage. Some of the material brought down 

in these channels was deposited in the lower parts of their courses and in the estuaries of the 

Manhasset coast, but most of it was swept beyond the present coast line. In general, therefore, where the outwash is thick it. overlies the 'Manhasset plain and valley alike, but where 

it is thin it rests largely in the valleys or other depressions of the Manhasset surface. 

DISTRIDU'.riON. 

West of Manhasset Bay, near the head of which the Ronkonkoma ridge disappears beneath 

~he later Harbor Hill moraine, no outwash f1:om ice along the Ronkonkoma moraine is recognizable, the deposits being entirely cove~:ed by the later drift. 

From. J ama~ca to the vicinity of the· M:annetto Hills stretches a great outwash deposit, 

constituting what has been. c;alled the Hempstead plains. The deposit is evidently made up 

of outwash material, part assocjated with the Ronkonkoma and part with the Harbor Hill 

moraine, but it has been :impossible to differentiate these parts in the region as a whole, owing 

' 
168 GEOLOGY OF LONG ISLAND. 

to the similarity of material and the absence of distinct topographic features. From the later 

. Harbor Hill moraine several distinct channels pass through the Ronkonkoma moraine and 

lead southward across the outwash. The incision of these Harbor Hill channels shows that 

near the Ronkonkoma moraine at least the outwash from ice along the Ronkonkoma moraine 

is the principal surface deposit, reaching a height of 120 feet. Farther south many of the 

channels are less marked and indications of a spreading out of the later outwash in fans over 

the earlier outwash are observed. 

In and around the west side of the Mannetto Hills is a local area of outwash from ice along 

the Ronkonkoma moraine without, any apparent admixture of later drift, reaching a maximum 

elevation along the base of the moraine of about 200 f~et. A similar area, now standing as a 

terrace 30 feet above the later outwash, or about 180 feet above sea level, is seen on the west 

side of the Dix and Half Hollow hills, and a smaller area is found on the southwest flanks of 

the group of hills between the Dix and Mannetto groups. The greater part of the area between 

the groups of hills and between the hills and the coast, however, seems to be outwash from ice 

along the Harbor Hill moraine. 

From the Half Hollow Hills to Brentwood is a broad stretch of outwash from ice along the 

Ronkonkom,a moraine rising to the height of 150 feet or more and having a typical contour. 

East of Brentwood, however, the outwash, though still present in considerable amounts, becomes 

r-d 

'Q1 • .-! ·~ 

]~~ ~ Manhasset level 100 . 

so' 

j 

t/) 

1~ ,4"1 

~ Outwash ~ level 

0~------------~Se~~-l~e~~~l------------------~ 

FIGURE 196.-Profile of Carmans River outwash channel near Yaphank. 

thinner and the gravels of the Manhasset 

formation project through itatintervals. 

Its maximum elevation js about 160 feet. 

AtConnetquot River the composite plain 

is interrupted by a broad outwash ~hannel of the Harbor Hill substage, while 

south of Yaphank it is cut by a still 

broader channel of outwash from ice 

along the Ronkonkoma moraine unmixed with :Manhasset material and apparently deposited in a broad valley or estuary in the Manhasset formation. The profile along 

the railroad near Yaphank station shows the relations of the outwash from ice along the Ronkonkoma moraine to the :Manhasset formation and the notching due to Vineyard erosion 

(fig. 196). 

From Yaphank to Shinnecock Canal the same intermixture of outwash and Manhasset 

forms that was noted west of Yaphank is observed (elevation along moraine 80 to 140 feet), 

but between Shinnecock and Mecox bays the outwash, although much lower, predominates. 

From Mecox Bay to and beyond Bridgehampton the topography is again composite, the Manhasset rising above the outwash at many points and even where below the outwash manifesting 

its presence by kettle channels and other similar features. The marked kettle channel at 

Scuttle Hole has been described (p. 43) and illustrated (Pl. IX, A, p. 42). Outwash deposits 

rise to 150 feet at this point. From Bridgehampton to Easthampton the outwash again controls the topography (Pl. XXI, A, p. 118), altl;wugh considerable influence is exerted locally by 

the Manhasset and the surface is extensively modified by the fonnation of dunes west of Georgica 

Pond. From Easthampton to Promised Land the topography is of the mixed type (Pl. L~I, B). 

No outwash from ice along the R6nkonkon1a moraine is found on Montauk. 

HARBOR RILL MORAINE. 

NAME. 

After the upbuilding of the Ronkonkoma moraine and the associated outwash plains the 

ice retreated northward to or above the line marked by the northern or inner moraine and, 

perhaps after some fluctuation, finally halted. on this line. The northern moraine, which extends 

from New York Harbor on the west to Orient Point and beyond on the east, has been designated the Harbor Hill moraine, from the hill of that name near Roslyn, at the head of Hempstead Harbor, this being the highest point of the moraine on Long Island (384 feet). 

• 

A 
·~ 

WISCONSIN DRIFT. 169 

CHARACTER AND SOURCE OF MATERIAL. 

Till is much more abundant in the Harbor Hill moraine as a whole than in the earlier 

Ronkonkoma moraine. This is especially true in the region west of the point where the Harbor 

Hill moraine crosses the Ronkonkon1a moraine. From this point stratified materials rapidly 

decrease in amount, and till becomes more conspicuous, and from Jamaica westward nothing 

but till is seen in n1ost of the exposures, even where these are 25 to 30 feet or more in depth. 

The 1noraine in this part of the .ishtnd is, in fact, composed practically of till, consisting largely 

of Triassic material brought from_ the northwest across Hudson River. Bowlders abound in 

this region (Pl. V, B, p. 32). 

East of the point where· it crosses the older ridge the Harbor Hill moraine becomes more 

gravelly, stratified materials being observed practically to the top of Harbor I-Iill. In this 

region the moraine contains much stained quartz from the Mannetto gravel and some white · 

quartz from the Cretaceous. Till is not· at all uncommon and bowlders are fairly nnmerous, 

though generally small. From the vicinity of Oyster Bay eastward to Port Jefferson both till 

and gravel are largely represented in the moraine, but sandy phases, such as occur in the outer 

1norai.ne, are not common. 

East of Port Jefferson the moraine, although containing abundant stratified material, 

carries n1ore unstratified drift, especially bowlders, which in places line the beach or even form 

bowlder pavements and heaps extending for considerable distances. The bowlders considerably 

exceed in number those in the outer moraine an<;l their average size is much larger. Several 

from 30 to 50 feet in diameter have been seen. 

In general the source of the material is similar to that of the material in the Wisconsin till 

sheet, for it likewise varies in character according to the nature of the material over which the 

ice passed. Granitic pebbles and bowlders are more common in the inner than in the outer 

moraine, indicating a greater percentage of materials, at least of the coarser sizes, from the 

1nainland. 

RELATIONS 1'0 OLDER DEPOSITS. 

The IIarbor Hill moraine, like the Ronkonkoma, rests upon the eroded surfaces of several 

older formations. West of Hempstead Harbor it lies upon gravels of the Manhasset formation, 

the surface of which descends westward from about 180 feet above sea level near Roslyn to 

sea level or below at the Narrows of New York Harbor. For several miles e·ast of Roslyn the 

moraine seems to be underlain by Marinetto remnants reaching a height of considerably more 

than 200 feet. To judge from the topography of the deposits of this character south of Wheatley, 

the buried Mannetto surface must be very irregular (Pl. VI, D, p. 32). From this point east-: 

ward to the end of the North Fluke the relations of the moraine to older deposits, though irregular, are very simple, the moraine resting almost solely upon the Manhasset surface, stretching 

across its flat terraces, descending its slopes, and crossing its deep valleys.. The elevation of 

the base of the moraine ranges from a little below sea level to the level of the Manhasset Plateau. 

This plateau gradually declines from an altitude of 200 feet near Huntington to 160 feet in the 

vicinity of Port Jefferson, 80 feet north of Riverhead, and scarcely 20 feet at Orient Point. 

DIS1'RIBUTION. 

The I-Iarbor I-Iill moraine shows a distinctly loba.te form, the lobes being, however, on R 

smnller scale than those of the Ronkonkoma ridge and apparen.tly being due to the influence of 

the bottom of the Sound or of the form of the north shore upon the movement of the ice. The 

lobes are not, however, marked by any distinctive characteristics of composition, structure, or 

form. 

The part of the moraine west of Manhasset Bay differs from that in any other portion of 

the island both in composition and topography. The material is here practically all till, the 

moraine possessing a more subdued topography, the steep hills, slll.all cones, irregular gravel heaps, 

and steep-sided kettles characteristic of the stratified moraine being replaced by larger, more 
170 GEOLOGY OF LONG ISLAND. 

regular hills with relatively gentle ·slopes and less·irregular, shallower, and less abrupt depressions. The moraine in this region rises to a height ranging from 100 feet in the vicinity of the 

Narrows to nea.rly 260 feet southwest of Manhasset Bay, or from 80 to 100 feet above the l\1anhasset formation, upon which it rests. A feature of the ridge in this part of the island is the 

distinct erosion scarp along its south side from the vicinity of its junction with the older moraine 

south of Manhasset Bay westward to Brooklyn (Pl. XI, D, p. 52). This, however, is a subsequent feature and not a normal phase o{ moramal development. 0 

East of Manhasset Ba.y there are no important gaps in the continuity of the moraine, the 

ridge being unusually persistent and uniform. At the heads of Manhasset Bay and Hempstead 

I-Iarbor, hpwever, the moraine is cut by sharp and deep channels leading southward across 'the 

outwash plain. Each of these gaps or passes has an altitude of about 180 feet, or very nearly 

that. of the Manhasset surfa<;e. The .moraine rises to a height of 384 feet in Harbor Hill, or 200 

feet ~boye the Manhasset level. Exposures in large gr~vel pits in the valley beneath the moraine 

near .Roslyn show horizontal Manhasset d~posits, establishing the superficial character of the· 

morainal accumulations. 

East of this point for about 7 miles the ridge is practically continuous, although gradu·ally 

declining in elevation until near Cold Spring Harbor it hardly rises above the Manhasset outwash levels. .The valley at this point, although the slopes are more or less covered with till, 

seems to have been occupied by residual ice during the up building of the morainal and outwash 

deposits, and to this fact' it owes its freedom from Wisconsin filling. 

From Cold Spring Valley to a ppint near· the bend of the railroad east of Greenlawn the 

moraine is again fairly continuous, although a break or' some importance is found 2 miles r.. . ... 

southwest of Huntington. Near the bend of t4e r~i,Jroad mentioned there is a still more important break marking the passage of an outwash channel, which can be distinctly traced to 

Babylon, on the south shore. Other breaks occur between Larkfield and Kings Park stations, 

at Nissequogue River, and at Port Jefferson. · At the last-named .pomt a large gravel pit 

gave (in 1903) an almost complete section of the Manhasset formation up to the base of the 

overlying moraine, conclusively showing the superior stratigraphic position of the morainal 

ridge . 

. The ·'rolling topography of the Harbor Hill moraine is exhibited east of Port Jefferson, 

where, although ~he cliff is generally covered with talus, enough can be seen to show that the 

morainal till is a superficial deposit resting on horizontal gravels of the Manhasset formation, 

which make up three-fourths of the bluff. The moraine in this interval, although still haVing 

the nature of a ridge, in places rises less than 50 feet above the Manhasset terrace on which 

it rests. It is marked, however, by kettles· that are more conspicuous than any found west 

of this point, some of them 40 to 60 feet in depth and having unusually steep slopes. 

East of Port Jefferson station the moraine· ~s essentially of the "depressed" type fo~ 2! 

miles (Pl. VII, B, p. 34), there being practically no ridge. Instead, the outwash plain breaks 

off sharply into a belt of immense kettles (fig. 12, p. 34), the bottoms of which lie as low as 

100 to 120 feet above sea level, or 60 to ~0 feet below the surrounding plain. 

Near :Miller Place the moraine again takes the form of a ridge, which persists without 

notable breaks for more than 10 miles. It reaches an elevation of 220 feet southeast of Miller 

Place, 260 feet near Rocky Poirit village, 246 feet northeast of W ardencliffe, and 230 feet 

northeast of Wading River. As the Manhasset rises but little over 100 feet above the sea in 

this region, the Harbor Hill moraine is thicker here than in most other places on the island. 

The bowlders _in it rapidly increase in number and size east of Port Jefferson, although they 

are not so numerous on the beach as at points farther west, because the waves have not cut 

so far into the moraine. Among the largest of the inland bowlders is one found half a mile 

northwest of Wading River village near the marsh. It is a sharp pyramid of granite having 

. a height of 20 feet, a base measuring 18 by_ 15 feet, and a cubic cpntent of about. 4,000 feet. 

About it lay several other large fragments, apparently originally parts of the same bowlder 

One of these was over 10 feet in diameter and contained 1,000 cubic feet or more. A still 

• 
WISCONSIN DRIFT. 171 

inore massive bowlder was seen just north of the highway from Wading River as it turns to go 

up the v~lley toward Wardencliffe, a little over a mile west of Wading River. Although partly 

buried this block probably measures 20 by 20 by 16 feet and contains about 6,400 cubic feet. 

Between Wac.ling River and Fresh Pond Landing· the morainal 'development rapiclly . 

weakens, the crest declining from a height of over 220 feet, or 120 feet above the Manhasset, 

at a point southwest of Paines Landing to 150 feet, or only 50 feet above the :Manhasset, near 

Fresh Pond Landing. In fact, this point marks the end of the moraine as a prominent ridge, 

a considerable part and in places even the whole of the ridge farther east, although generally 

regarded as a moraine, consisting in reality of sand dunes. It. is, however, very difficult to 

separate the two in the absence of sections, for a coating of sand a few feet· thick may cover 

and obscure morainal accumulations of great importance and give the ridge the appearance of 

being composed of dunes when it is in reality largely morainal. For this reason it has been 

thought best, except where the dunes are known to predominate, to map the ridge as moraine. 

Iri. general, the moraine east of Fresh Pond Landing may be describe<;! as ranging from a 

low disconnected ridge to isolated patches of morainal drift, the whole covered in many places 

with a thick coating of dune sand. Here and ~here, as northwest of Centerville, the morainal 

deposits reach an altitude of 240 feet, or 140 feet above the Manhasset, but in general·170 feet 

is the maximum e~evation and 80 feet the height above the Manhasset. The moraine is here 

usually a narrow ridge, which in places retains but a fraction of its original width, the·remainder 

having been cut away by the sea, as shown by the bowlders upon the beach and in the water 

as well as by the topography. The seaward side of the moraip.e is generally a steep bluff more 

or less covered with talus, and the inner_ side is a mor~ gentle depositional slope. 

The pseudomorainal . character of the ridge where it consists predominantly of sand has 

been mentioned. It is well brought out by Plate VIII, B (p. 34), which shows a ridge 20 feet 

or more in height and exhibiting a topography that would ordinarily be regarded as unquestimiably morainal, but the section shows :lt to consist entirely of dune sand. The morainal 

accumulations are here represented o~y by the till less than 5 feet thick underlying the sand. 

Plate VIII, A, is a distant view of a much larger hill, probably not less than 50 feet high, which 

likewise appears to consist largely of dune sand. . 

The region east of Riverhead, more especially that. east of Greenport, presents many 

opportunities for· determining beyond all question· the relations of ·the moraine to the :Manhasset formation, many· sections both in the bluffs and in the amphitheaters and ravines 

showing the thick till of the moraine rest~g upon horizontal :Manhasset beds. In 1903 the 

best sections seen were half a mile northeast of Inlet Point, north of Greenport, and near ,, 

Rocky Point, east of Marion. Any storm, however, is likely to' change materially the char~ 

ncter of the sections. Those seen in 1903 were no longer con~picuous in 1904, but probably 

others equally good have been exposed since. Care should be taken not to mistake the Montauk till member of the Manhasset formation, which occurs in considerable thickness at the 

top of the bluff at several points, for the Wisconsin morainal deposits. 

The immense number and large size of the bowlders on the north coast from Greenport 

eastward constitute a striking feature. Not only is much of the beach covered with an 

unbroken pavement, but the· bowlders· are in places piled upon one another in great masses. 

Plate·XXIV, A, shows the appearance of the beach where a moderate number ofbowlders are 

present. A list. of a number of the largest of those that have been measured or estimated is 

given below. It should be noted, however, that many of these b~widers lie in front of cliffs 

in which both Wisconsin and Montauk materials are exposed and that a portion unquestionably 

belong to the older deposit (~font.auk). · 
172 GEOLOGY OF LONG ISLAND. 

Large bowlders on Long Island. 

Location. Situation or reference. 

• Near Whitestone Point .................... Reported by R. D. Salisbury a ........................... . Near Eden Point .......................... Reported by R. D. Salisbury ............................ . Southeast of Manhasset .................... Reported by Warren Upham b ••••.•••..•••••••••••••••••• 

North Hempstead ......................... Reported by Samuel L. Mitchill c .•.••...........• · ..•..•.. 

~mile southeast of Lloyd Point........... On beach; probably from Wisconsin till . .' ............... . ! mile south of Halesite.... . . . . . . . . . . . . . . . In till in Manhasset Valley .............................. . t mile south of Crane Neck Point .......... In Montauk till member of Manhasset formation ......... . ~mile south of Port Jefferson .............. In till in Manhasset Valley ............................... . t mile west of Woodville Landing......... On beach in front of moraine ............................. . 1! miles west.of Wading River............ Near highway through valley in moraine, etc ............ . ~ mile northwest of Wading River. . . . . . . . . Slope of moraine near edge of marsh ...................... . 

East Landing, Wading River............. On beach in front of moraine ............................. . Near Hulse Landing ...................... On beach and in water. Both Montauk till member of 

Manhasset formation and Wisconsin drift present in 

bluff. 

Near Friars Head .............. · ................ do ................................................... . t mile west of Jacob Point ........... · ........... do ................................................... . Middle of Oregon Hills.................... On beach in front of moraine ............................. . t mile west of Duck Pond Point ................ do ................................................... . 11 miles east of Horton Point .............. In water in front of moraine ............................. . ! mile east of Inlet Point.. . . . . . . . . . . . . . . . . On beach in front of moraine ............................. . t mile east of Inlet Point.................. Bowlder pavement on beach in front of moraine ......... . t mile southwest ofJnlet Point ................. do ................................................... . ~mile southwest of Rocky Point.......... In water in front of moraine .............................. . East of Rocky Point...................... On beach in front of moraine ............................. . 

Jennings Point1 Shelter Island ............ Reported by F. J. H. Merrill d ••••••••••••••••••••••• : •••• 

2 miles north oi.Eastport.................. In moraine. Reported by John Bryson e ••.•••.••.••..••. 

Size. 

20-foot bowlder. 

Do. 

54 by 40 hy 16 feet. 

40 feet long, 20 to 40 feet wide, 10 to 17 feet 

high. 

17 by 14 by 9 feet. 

Diameter 20 feet. 

Diameter 30 feet. 

35 by 20 by 5 feet. 

25 by 10 feet. 20 by 20 by ~6 feet. 

Pyramid, base 20 by 18 feet, height 15 

feet. 

25 by 20 by 6 feet. 

Hundreds from 10 to 20 feet in ciameter, 

30 by 15 by 8 feet. 

38 by 20 by 11 feet. 

Diameter 15 feet. 

Base 23 by 20 feet; height 10 to 18 feet. 

Diameter 25 feet. · Do. . Many over 10 feet in diameter. 

Do. 

25 by 25 by 30 feet. 

Several bowlders 20 to 25 feet in diameter. 

Probably 30 to 40 feet before. 

9,000 cubic feet. 

50 feet in ·circumference, 20 feet high 

(originally 125 feet in circumference). 

aNew York City folio (No. 83), Geol. Atlas U.S., U.S. Geol. Survey, 1902, p. 14. b.Am. Jour. Sci., 3d ser., vol. 18, 1879, p. 201. c Med. Repository, vol. 3 1800, p. 330. 

dAnnals New York Acact: Sci., vol. 3,1886, pp. 341-364. e Am. Geologist, vol. 16, 1895, pp. 228-233. 

Owing to the covering of dune sand, it is not always possible, to recognize small breaks in 

the morame. The first break in the region east of Fresh Pond Landing is northwest of Baiting 

Hollow, where the outwash, except for a thin coating of dunes, reaches the edges of the bluffs 

bordering the north shore. At Mattituck Inlet is· a more important break, the gap here being 

more than a mile wide and extending to sea level. A small break with a southward-leading 

channel intersects the Oregon Hills. Other. important breaks occur at Hashamomuck Pond 

and a mile northeast of that place, both the moraine and the Manhasset formation being cut 

to or below sea level. This shows that before their connection by sand bars and marshes what 

is now the North Fluke consisted of a number a. detached semimoramal islands, such as Plum 

Island is to-day. The most. easterly break is at Truman Beach, near Orient, this likewise 

" marking a former channel between islands. 

OUTWASH FROM ICE ALONG HARBOR HILL MORAINE. 

GENERAJ. CHARACTERISTICS. 

The deposition of the Ifarbor Hill ridge, like that of the earlier moraine, was accompanied 

by the formation of a more or less extensive outwash deposit. In composition this deposit shows 

no material difference from the outwash from the ice along the earlier (Ronkonkoma) moraine 

already described (p. 166), varying in the same manner from point to point according to the nature 

of the materials over which the ice passed. The. sources of the materials of the two outwash 

deposits are practically identical, and so far as can be seen, the mode of deposition and character 

of the bedding (flow and plunge structure, etc.) are likewise the same. The brownish sandy 

or pebbly loam and clayey sand (comparable with the so-called Ja.mesburg loam of New Jersey), 

described as locally forming superficial coatings over the outwash from ice along the Ronkonkoma moraine, are likewise present in places on the outwash from ice along the Harbor Hill 

moraine, the most conspicuous developments being (1) in the easterly of two outwash channels 

northeast of I-Iigh Hill, (2) in the region southeast of Elwood and northeast of the Dix Hills, 

(3) in the district north of Coram, (4) at points between Wardencliffe and Ridge, and (5) in 

the region south of Manorville. It is also found locally near Jamaica. Like the outwash 

from ice along the Ronkonkoma moraine, the outwash from ice along the Harbor Hill moraine 

• 

.• 
WISCONSIN DRIFT. 173 

rests upon the eroded surface of graveJs of the Manhasset formation, and being, as a rule, relatively thin, in many places fails to· hide the Manhasset topography, which is made apparent to 

the eye by the numerous kettle valleys or by elevations rising above the outwash level. The 

topography of the outwash differs in no essential way from that of outwash along the Ron- ' 

konk01na n1oraine. 

DISTRIBUTION. 

J.Varrows to Jamaica.-The plains in the stretch of more than 15 miles between the Narrows 

and Jamaica are low and flat, and exhibit a lobate fan-shaped outline with radiating drainage 

creases converging toward the base of the moraine at three distinct points-near Prospect Park, 

in Brooklyn, at East New York, and near Dunton, southwest of Jamaica. The surface is locally 

covered by a foot or more of brownish. loam resembling the "Jamesburg loam" of New Jersey 

(p. 172). 

Roslyn-Ilempstead region.-The deposit in the area between the moraines south of Roslyn 

has been described under Manhasset formation (p. 116). It may be regarded either as a kettle 

plain over a :Manhasset surface or as a thin outwash among higher Manhasset hills, but more 

probably it is a combination of 'the two. South of the outer moraine the kettles disappear 

rmd the later and earlier outwash deposits merge into the broad Hempstead plains, in which 

they could not be differentiated. 

Wheatley-Gold Spring region.-From the Wheatley Hills to the valley at Cold Spring 

station the outwash from ice along the Harbor Hill moraine is represented by a narrow strip, 

in few places more than 2 miles wide, of what may be called a kettle plain, the ordinarily smooth 

outwash surface being broken at many points by kettles, some steep-sided and of considerable 

depth, which evidently n1ark the former positions of melting ice masses in the valleys of the 

:Manhasset formation, which is here not far below. the outwash surface. 

Huntington-Babylon region.-Stretching sol.l thward from the Harbor Hill moraine between 

Cold Spring Valley and Greenlawn is one of the most strongly developed ol.l twash deposits. 

from ice along the liarbor Hill moraine. In detail it consists of two broad level outwash channels from half a mile to 1! miles in breadth, one leading southeast from the morainal ridge 

near Cold Spring and passing between High Hill and the hills south of the Huntington fair 

ground, the other leading southwest fron1 the ba:se of the ridge near Greenlawn and passing 

between the Dix I·Iills and the hills before mentioned, the two uniting near Melville between the 

Mannetto and Half IIollow hills. Between the two channels, in the vicinity of the fair ground, 

is an extensive area of otitwash of the kettle-plain type. Many of the kettles are more than a 

qtiarter of a mile long, two more than half a mile, and one more than a mile. ·several kettles, 

-especially the largest, have a branching form such as would characterize kettles restilting from 

the melting of ice masses in old :Manhasset valleys, and this, in fact, is probably thejr origin. 

Some of the ice blocks evidently rose distinctly above the outwash surface, for ridges, apparently 

of materials set free from the melting of the ice masses, are found on the kettle rims along the 

fair-ground road and elsewhere. 

The deposits of the united outwash ehannels pass southward as a belt more than 2 miles 

in breadth between the Mannetto and Half Hollow hills, beyond which they spread out in a 

broad fan stretching along the coast from Massapeql.la to Babylon. 

The greater part of the outwash, including most of that south of the M:a1metto and'Half 

I-Iollow hills, appears to have been deposited during the earlier stages of the Harbor Hill ice 

haJt and before the melting of the ice blocks in the intermorainic district. It is probable that 

at this time the entire area between the moraines was of the kettle-plain type. In the later 

·stages of the ice halt less material was set free, the waters coming mainly from two points, one 

at each end of the area. By this. time the ice blocks seem to have largely melted and the kettles 

along the two outwash streams beeame filled. No further materials, however, appear to have 

been deposited in the Fairground area between these streams. So slight was the amount of 

detritus carried by the streams that it appears to have been deposited before Melville was 

.reached, the waters at this point gathering into definite channels, one on each side of the valley, 
174 GEOLOGY OF LONG ISLAND. 

leading southward toward the coast. Of these. -channels the one on the east side continues 

sharp and distinct to the point where it empties into· Great South Bay, near Babylon, but the 

more westerly stream was apparently weaker. and its channel is somewhat indefinite in the 

lower part of its course. 

Smithtown region.-East of Greenlawn thick outwash is found only in a belt a mile or two 

in width along the base of the moraine, beyond which the Manhasset approaches the surface 

and exerts a decided influence on the topography. East of a line from Kings Park to Commack 

the outwash entirely disappears, leaving the broad drainage basin of Nissequogue River (Pl. X, 

p. 46) as destitute of outwash as it is of till. (See p. 162.) This is the so-called Smithtown · 

'' driftless '' area. 

Port Jefferson region.-At Smithtown Branch and St. James the outwash is again recognized along the moraine, but it decreases in thickness toward the south, 1\1anhasset drainage 

lines being recognizable within 2 or 3 miles of the moraine. The southerly part of the belt 

is dotted by kettles, many of thein occupied by ponds, the largest and most beautiful of ~hichis 

the well-known La~e Ronkonkoma. Several of the depressions are of the kettle-valley type. 

South of Port Jefferson the outwash plain is well developed for 2 miles or more south of the 

moraine, but irregularities in the form of kettles appear near Terryville, and a little farther 

south low but distinct ridges and valleys, such as everywhere characterize the Manhasset surface, 

are seen. It is evident that the outwash is very thin and probably is confined largely to the 

valleys. The surface of a considerable area near the outer moraine has been reworked by winds 

and a c.oating of dune sand spread over it, in places completely hiding the underlying materials. 

Rocky Point and Riverhead area.-East of Port Jefferson the outwash becomes still thinner; 

and kettle valleys and even unfilled Manhasset drainage channels are seen close to the moraine at 

numerous points, as near Rocky Point, 

~~~~f[J-;~~~:~~~' ---- ~~~~~: ~~~~t~~1~~;::::~ ~!£i~:~: FIGURE197.-KettlerimoftillnearhighwaybetweenMattituckandCutchogue. Pis. IX, B, p. 42; XX, p. 116) are 

among the most conspicuous on the 

island, individual kettles reaching a depth of 60 to 80 feet and having a length of several miles. 

Northwest of Riverhead chains of kettles, instead of single elongated hollows, mark the Manhasset valleys (Pl. IX, 0). One of these is 4 or 5 miles long. Some of the kettles are marked 

by raised rims, apparently consisting of material set free from the ice blocks, which must therefore have risen above the surrounding surface. 

The true outwash from ice along the Harbor Hill moraine does not extend south of Peconic 

River, the Wisconsin materials there consisting of kame and local outwash deposits resting on 

an irregular Manhasset surface, the whole having a distinct morainal aspect. The deposits are, 

nevertheless, in the main sharply separated from the Ronkonkoma morainal ridge and are 

better mapped as outwash than as moraine. · 

North Fluke.-On the North Fluke the outwash plain becomes narrower toward the east, 

being about 4 miles wide at Riverhead and absent at Orient Point. It becomes progressively 

thinner and the Manhasset controls more and more of the topography. There are, however, 

fewer kettles and kettle valleys, presumably because the Manhasset surface, on which the out-

. wash rests, was more level than at points farther west owing to its slight elevation and consequently less-marked erosion. Kettles are nevertheless not uncommon, especially between 

Riverhead and Mattituck, and open Manhasset or kettle valleys nearly or quite cut through 

this fluke at Mattituc~ and at Hashamomuck and Truman beaches. Some of these kettles 

show, in addition to the usual bowlders, marginal ridges of drift set free by the melting of the 

ice blocks. One of the best examples of these, found about 1! miles northeast of Mattituck 

on the road to Cutchogue, is shown in figure 197, the rims being raised about 20 feet above 

the surrounding plain. A pair of kettles near the second road leading northwest from the 

Cutchogue-Southold highway, about 1! miles northeast of Cutchogue, showed a sharp connecting crease as if cut by water flowing from one into' the other. 

• 
•' 

WISCONSIN DRIFT. 175 

OU'l'W ASH CHANNELS. 

In the later part, or at· the end of the I-Iarbor I-Iill substage of outwash deposition, the outflowing glacial waters we:i·e no longer overloaded with debris, and hence ceased to deposit and 

began to erode. As a result numerous well-defined and some large channels leading southward 

toward the sea were cut in the surface of the outwash. The greater number of these channels 

start at or near the Harbor Hill moraine and cross the island to the south coast, but some 

start at the 1noraine and become indistinct before reaching the sea and others begin sever~ 

1niles south of the moraine. 

Roslyn channel.-The most western. channel of importance is that starting at the gap in 

the moraine at Roslyn. This is .a sharp, well-defined channel several hund.red feet wide, about 

15 feet deep and in places, as at the road ha.tf a mile south of Roslyn station, characterized 

by a low terrace between the bottom and the outwash level. Its course is shown by the geologic 

1nap (Pl. I, in pocket). 

Melville channels.-The next important channels are those ieading southward from Melville 

between the Marmetto and Half Hollow hills. The character and sign:ificance of these channels 

hn.ve been discussed in another place (p. 49). 

Centerport-Babylon channel.-One of the most persistent of the smaller channels is that east 

of the Dix I-Iil1s. Starting at the moraine near the head of Northpo'rt Harbor, it extends across 

the steep outwash fans to Elwood, across the combined outwash and Manhasset to Commack, 

through the Ronkonkoma moraine at the' east end of the Dix Hills, and across the outwash 

from ice along the Ronkonkoma moraine to the south shore at Babylon, 16 miles from its point 

of beginning. 

Oonnetqu::>t channel.-The broad Connetquot channel, which measures from a mile to a 

1nile and a half in width, starts near .Smithtown and runs first eastward and then southward, 

emptying into Great South Bay between Islip and Sayville. In many respects it is unique 

an1ong the Long Island channels. It neither heads in the moraine nor develops in an outwash 

plain. Instead, it starts high above drainage level on the east side of the Smithtown'' driftless" 

area (Pl. X, p. 46) and makes a broad bend to the northwest and then another to the south 

before finally passing through the outer moraine. The northerly and easterly side of the channel 

is marked by a sharp and distinct scarp, 20 to 30 feet or more above the floor of the channel, 

and intersected at short intervals by drainage creases, now streamless. The same scarp is found 

at the gap in the moraine and on both sides of the channel for some distance to the south, but 

it gradually ·becomes less conspicuous and is bounded by gentler slopes. Many of the tributary 

drainage creases are well-developed and branching, being far more advanced than any other 

post-Wisconsin channels on the island. A similar drainage system is found a short distance 

to the east, converging toward the gap in the moraine through which the main channel passes. 

The a<ivanced stage of develop1nent of the Nissequogue drainage systen1 on the west side 

of the river suggests that a similar stage may have existed at some time on the east. This 

the writer believes to have been the case, the headwaters being represented by the larger branching chmmels entering the C01metquot channel between Smithtown Branch and the ~oraine. 

Another drainage· system with its principal headwaters northwest of Lake Ronkonkoma, , 

but with another branch heading son1ewhere east of Ilauppauge, is thought to have led southward nlong the present course of Connetquot River. -Before the advance of the main Wisconsin 

ice sheet the western half of the Nissequogue drainage basin appears to have been covered 

with snow or snow ice, so that the glacier passed over to the moraine beyond without either 

disturbing the surface or covering it with drift. In the eastern part of the basin, however, 

the conditions were different, at least in the later part of the invasion, and sufficient drift, 

1nainly stratified, was deposited to cover and obliterate the drainage topography. The ice 

over the .western half of the drainage system persisted after the retreat ·of the ice fron1 the 

Ronkonkon1a n1oraine, but in the eastern half only a few buried masses remained. Over this 

eastern area, it is thought, there swept large quantities of water, the current following the 

outside of the curve marking the easterly boundary of the Connetquot channel from Smithtown Branch to the Inoraine, cutting the sharp terrace which lies just east of the highway 
176 GEOLOGY OF LONG ISLAND. 

between the points mentioned, crossing the old 'divide east of Hauppauge, and flowing down 

a pre-Wisconsin channel of a tributary to the stream heading in the district northwest of Lake 

Ronkonkoma. After the cessation of the outflow the ice masses underlying the outwash 

deposits melted, leaving the rolling surface now seen, a;nd the erosion of the minor notches in 

the cliffs began. The history outlined is somewhat complicated, but it see~s to fit the facts 

better than any other explanation yet proposed; 

Oarmans River channel.-The only other channel of importance is that along Carmans River 

in the vicinity of Yaphank. Most of that part lying south of the moraine belongs to the Ronkonkoma substage, but a narrow channel along the present stream seems to belong to a later 

stage. The channel is believed to mark an intermediate outwash deposit laid down later than 

the Ronkonkoma moraine but earlier than the Harbor Hill moraine and the outwash from ice 

along it. (See fig. 196, p. 168.) RETREATAL DEPOSITS. 

The final retreat of the ice from its position upon the surface of the gravels of the Manhasset 

formation appears to have been accompanied by no considerable outwash, the deposits that 

were left on the surface during the retreat being composed of till rather than gravel. In some 

of the cliff sections a few feet of gravel rests on the till and it is believed to represent outwash 

deposits of the final retreat." Such deposits, however, are more commonly absent than present. 

Some of the swells breaking the regularity of the plateau-like Manhasset surfaces may repres·ent 

low, flat outwash fans of this stage, but the number of bowlders lying upon most of the surface 

seems to indicate that the top deposits are mainly of till. Channels cut by streams issuing 

from the ice sheet during its retreat persist at several points. 

R. D. Salisbury 1 and his associates mapped considerable areas on the north side of the 

island 'from East River to Flushing Bay as stratified drift of the last retreat, and as there was 

no opportunity for a reexamination of the area, this mapping has been followed in the present 

report. The fact that the surface gravel overlies the main drift. of the region does not, however, 

necessarily indicate that it is Wisconsin. On the contrary it may be the Hempstead gravel 

member of the Manhasset formation resting upon the Montauk till member of. the Manhasset, 

as was found to be true of the College Point "kames," the Wisconsin till in many places being 

almost unnoticeable. 

The most satisfactory exposure of retreatal material is found on Manhasset Neck northwest 

of Port Washington (Pl. IV, p. 30), where a broad delta exhibiting characteristic foresets and 

topsets was formerly to be seen but has been now largely removed for the sand and gravel it 

contained. According to J. B. W oodworth,Z who studied the delta in detail, it was formed in 

a local glacial lake during the ice retreat, the water standing about 80 feet above the present 

level of the sea. 

A thin retreatal outwash deposit resembling that between the Harbor Hill and Ronkonkoma moraines south of Huntington mantles the surface of Lloyd Neck. At the time of 'its 

accumulation ice masses still rested in its valleys and on_ their subsequent melting gave· rise to 

the numerous kettles and kettle valleys. Thes~ are well shown by the topographic map (Pl. 

II, in pocl}et). · 

RECENT SERIES. 

EXTENT. 

The Recent deposits, although not extensive compared to the glacial and older mater_ials, 

are nevertheless of considerable importance. A stretch of nearly 100 n1iles of beach, probably 

averaging a quarter of a mile in width, has been constructed, making an addition of 25 square 

miles to the area of the island. The largest addition, however, has been made through the 

growth of the salt marshes, which have extended the area of the island by at least 100 square 

miles. The fresh-water marshes probably have an aggregate area of 15 square miles or more, 

and dune sands cover about 25 square miles of inland territory in addition to that along the 

I New York City folio (No. 83), Geol. Atlas U. S., U.S. Geol. Survey, 1902. 2 Bull. New York State Mus. No. 48, 1901, p. 653. 
R:JilCENT SERIES. 177 

beaches. In all probably more than 125 square 1niles of the present area of the island is due 

to accun1ulation in Recent time. This, however, is probably more than counterbalanced by the 

land lost by erosion and by subsidence. 

STREAM DEPOSITS. 

Deposits in stream channels.-Although ·Long Island abounds with stream-cut valleys and 

cham1els, there are few stream deposits· that can be r"eferred to postglacial accumulation. 

On the plateau of the north shore the valleys are older than the last ice invasion, with the 

deposits of which their sides are locally mantled. The action of streams in Recent time is usually 

limited to a shallow notching of the valley bottoms or to slight washes of sand and gravels from 

their .sides. 

Most of the channels in the plains of the southern half of the island are not occupied by streams 

at the present time, evidently having been cut under conditions quite different from those. now 

existing. Some of these channels proceed from the outer or Ronkonkoma moraine, others rise 

b~ck of it, and still others even start from notches in the inner ridge, indicating that the source 

of the water was in the ice. Many of the.m-inor channels, however, are cut only a mile or two 

back fro1n the sea, and these, it seems likely, were cut, in part at least, by postglacial stream 

action before the protecting 1nantle of vegetation obtained a foothold. In the latter channels, if 

not in SOille Ot the forn1er, the surface n1aterials have probably been more or less shifted in postglacial tune and hence are to be included with the Recent deposits. The sam~ is true of many 

of the notchlike channels at points on the flanks of the moraines. 

Alluvial.fans.-At the base of each moraine there are many more or less fanlike accumulations of sand and gravel brought down as local wash, largely before the surface was covered 

with vegetatioi}, but in part by wash or creep in Recent time. These deposits are best see.ti 

where the n1orau1e is high and the materials are sandy, as in the region between the Dix Hills ~nd 

Cormn and at a number of points farther east, but are commonly too small to be indicated by 

the contours of the topographic map. Many small but well-developed fans also occur at the 

n1ouths of the ravines of the Mannetto and Half Hollow hills south of the n1oraine, and typical 

talus cones and fans occur at the base of the bluffs .and at mouths of ravines along the north 

shore of the island. · 

Deltas.-Because of the slight amount of postglacial erosion that has taken place, delta$ 

are, as would naturally be expected, practically absent at the mouths· of the valleys. , Small 

deltas from 50 to 100 feet in diameter are often formed during heavy rains from materials washed 

fron1 the rayines of the north shore, but theseare usually destroyed by the currents or waves 

in a short time. The harbors of the north shore and the. gr~at bays of the south shore are more 

or less filled with sands shifted about under the action of the tirle, but these deposits appear to 

bear no relation to the streams emptying into the sea in .the vicinity. Here and there deltas 

are formed by tidal currents b<?th inside and outside of the inlets through th~ beaches, but most 

of then1 are small. The shoal lying off the mouth of Nissequogue River is the only one of any 

consequence resemblillg a delta indicated by the charts. 

MARINE DEPOSITS. 

BEACHES AND SPITS. 

A long stretch of beach extends with a few interruptions from Coney Island to Southampton, 

a distance of nearly 90 miles, and separates from the ocean several partly or completely inclosed 

bays, such as Jamaica, Great South, Moriches, and Shinnecock. The longest stretch of unbroken 

beach is that extending westward from Southampton to Fire Island Inlet-a distance of 45 miles. 

This beach, which is almost a .straight line throughout its length, is rarely more than half a mile 

and generally less than a quarter of a mile wide. The part south of Shinnecock Bay is known , 

as Hampton Beach, but most of the remainder is designated Fire Island Beach. Waves occasionally cut tlu:ough it in time of storm, although the. openings are commonly soon closed again. · 

1629°-14-13 I,' 
178 GEOLOGY OF LONG ISLAND. 

Shinnecock Bay, just west of Southampton, 9 miles long and 3 miles wide, has at present no 

dire.ct connection with the ocean, but a canal· leads northward into Great Peconic Bay and 

another westward into Moriches Bay. An artificial cut made to the ocean was soon closed by 

the waves. Moriches Bay is con~ected through a narrow natural channel with Great South Bay, 

which in turn connects with the ocean through Fire Island Inlet. 

The beach is composed mainly of quartz sand, although some garnetiferous and magnetic 

materials are seen: Pebbles are generally scarce, but some are seen where the beaches connect 

with the. main island, as near Southampton and Westhampton. The surface above high-water 

mark is generally covered with dunes from '5 to 20 or even 30 feet in height, among which are 

scattered many small fresh marshes. The movement of materials by the waves is plainly westward, the chief source being between Southampton and Montauk, where the coast, as has been 

see~, has suffered considerable erosion. It is possible, also, that a part of the material has been 

thrown up from the shallow sea bottom of the vicinity by the action of waves. Practically no 

sand is contributed by the streams of the island at the present time. 

West of Fire Island is the beach know:n as Oak Island Beach in the eastern part and Jones 

Beach in the western part. This beach begin.s about a mile north and a little more than a mile 

east of the west ~nd of Fire Island Beach. It seems to have never been connected with the 

main island and appears to be older than Fire Isla~d Beach, which is now being built outside 

and overlapping it. It is therefore a pure barrier beach, .whereas Fire Island Beach partakes 

. of the nature of a spit. ' 

Just west of Jones Beach and separated from it by the narrow Zachs Inlet is Short Beach, 

about 2 miles in length. Beyond is Jones Inlet, followed by Long Beach, about 8 miles in length, 

and Far Rockaway and Rockaway beaches, which are continuous and together about 11 miles 

long. Manhattan and Brighton beaches, lying west of Rockaway Inlet on Coney Island, which 

are together about 5 miles in length, complete the list. All these beaches are without naturaJ 

connectipn with the main island and have derived no material directly fro~ it, being essentially 

barriers. They show some diversity in direction, with a tendency to overlap, seen where the 

Rockaway approaches the Manhattan Beach. 

North of Long, Jones, and Oak Island beaches there are a number of small sandy islands 

in a line parallel to the beaches, with which their longer diameters are also parallel. 

These appear to represent the earliest bars formed by the waves and currents in the shallow 

waters off the south coast. Later the longer·, higher, and more connected barriers, such as Oak 

Island, Jones, Long, and Rockaway beachas, were built up outside of the earlier bars from materials derived from the sea bottom. At the same time a spit was being projected westward from 

Southampton (Hampton Beach), composed of material derived from erosion of the shore farther 

east rather than directly from the sea bottom. Later, partly with material from the same 

source and partly with sands from the sea bottom, the spit was extended westward to Fire 

Island Inlet, slightly overlapping the earlier Oak Island Beach. 

The process of. formation of the beaches is not continuous. · Many feet m,ay be added in a 

single storm; aga~, the waters of the ocean may break through, leaving wide gaps in the previously continuous beach. There is also at many points a tendency to periodic changes from 

deposition to erosion. . Thus for a long time Fire Island Beaeh has been building outward, but 

· at the time of the present field work the waves were cutting it· away,. leaving everywhere at 

high-tide line a low scarp 4 or 5 feet high, giving a section through the original beach and its 

capping of dunes. · · · CONNECTING BEACHES. 

0 

When the ice of the last glacial advance retreated from the region there were many disconnected islets adjoining the main island. In most places the intervening waters were shallow, 

and waves and shore currents rapidly extended hooks ancbspits from the projecting points and 

later united many of them into connecting beaches, joining the previously independent islets 

and completing Lorig Island as it now appears. Marshes have also served as a connecting 

agency. Beginning at the west on the north shore, the first islet that has been joined to the 

main island is Hunters Point; next an unnamed island on the Sound in the northeastern part 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 82 PLATE XXV 

HOOI<ED SAND SPIT AT ENTRANCE TO SMITHTOWN HARBOR. 

Ph oto graph by Edward P. Buffet. 
R-ECENT SERIES. 179 

of Long Island City; then Tallman Island naa:r College Point; and Prospect Point on Manhasset 

Neck. All these are connected with the body of the island by marshes. East of Hempstead 

I-Iarbor Dosoris and East islands are connected by beaches; farther along Oak Neck and Center 

Island by beaches and marshes; and Lloyd and Eaton necks, including Duck and one other 

small island, by beaches. There are no further indications of former islands between this point 

and Southold. Between Southold and Greenport breaks exist at Hashamomuck Pond and at 

Pipe Cove, and there was a channel at each end of Trumari Beach, near Orient.· 

In the bays between the flukes Ram Island, ·Mashomuck Point, and another smaller iE}land 

were connected with Shelter Island by beaches, and Little Hog Neck was in like manner joined 

to the North Fluke. On the South Fluke the Montauk peninsula was connected with the main 

island by N apeague Beach, nearly 5 miles in length. Near Sag Harbor, ·Hog and Jessup necks 

and two smaller islands were connected by beaches or marshes, as were Cow Neck and a small 

island on the south side of Great Peconic Bay. There does not, however, seem to have been 

any natural channel at Canoe Place, west of the Shinnecock Hills, although the land at this 

point is only a few feet above sea level and but a few hundred feet in width. The canal banks 

show glacial deposits rather than beach sands. A former connection of the waters of Peconic 

and Shnmecock bays would ·have necessitated a sinkihg of 10 or 15 feet below the present level 

of the land, a submergence of which there is no evidence. 

SMALL SPITS AND HOOKS. 

Among the minor shore features of Long Island are hundreds of small spits and hooks. 

Many of them are very typically developed. They are naturally most common along the irregular part of the north coast west of Port Jefferson and on the shores of the bays between the 

North and South flukes. :M·any smaller ones are found on the shores of Great South Bay and 

other bays of the south shore. 

Currents sweeping along any stretch of coast. tend to move in straight or gently curving 

lines just outside of the headlands, rather than on lines conforming to the minor irregularities 

and indentations of the shore. The material that they transport is deposited, owing to the 

slackening of their progress, when deeper water is reached, forming bars more or less completely connecting the headlands and at many points inclos~g.areas of relatively deep water. 

The beach between IIorton and Duck Pond points, Southold, was formed in this way, and a 

second bar is in process of formation. In places, as near Peacock Point, between Oyster Bay · 

and IIempstead IIarbor, as much as 600 feet of beach may be built out in a few years.1 Where 

the currents are feeble or conflicting, or the supply of material is not abundant, small straight 

or curved bars are formed rather than the longer ones describe~. In either. case the bars generally 

continue to receive additions of material and are finally built up so that they come within the 

range of influence of the waves, which serve to pile up the materials still further, until they are 

brought above the level of the sea to form connecting beaches, spits, and hooks. Of the spits 

the more prominent are Lloyd Point and East Beach, on Lloyd Neck; Eato~ Point and West 

Beach, on ·Eaton Neck; the spit at the entrance to Smithtown Harbor or Nissequogue River 

(Pl. XXV); West Meadow and the opposite beach at Stony Bro<:>k; Setauket and :Mount Misery 

beaches on Port Jefferson Harbor; East beach, near :Miller Place; Long Beach, near Orient 

·Point; the spits at the north and south ends of Gardiners Island; Goff and Lazy points and 

flicks Island, nn the ~1ontauk peninsula; and Cedar Point, Sammys and Acabonack beaches, 

· between Sag }lm·bor and .N apeague Beach. (See Pl. I, in pocket.) Of these, Lloyd Point, West 

Beach, and the beaches at ~1ount Misery, Lazy, and Goff points, Hicks Island, and Cedar Point 

are of interest as being curved, hooked, or otherwise complex spits·. Many of the smaller un 

named beaches; such as those partly cutting :Hempstead and Cold Spring harbors, are of equal 

interest. 

MAGNETIC AND GARNETIF;EROUS SANDS. 

Among the most striking features of the material of the wave and current formed beaches 

of Long Island are ·the magnetic and gar~etiferous s~nds, which are seen at many points along 

1 Mather, W. W., Geology of New York, pt.l, 1843, p. 22. 
180 GEOLOGY OF LONG ISLAND. 

the coast, especially on the north shore. These s~nds occur at some places in beds from half an 

inch to 4 inches thick, several feet wide, and 10 to 100 feet long. They are usually found well 

above the ordinary water level at points where the waves have beaten at unusually high tides 

or in times of storm. This is commonly at the very base of the bluffs. Farther down the beach 

the grains may be either mixed with the coarse sand or gravel, as along parts of the north shore, 

or they may occur as a surface film on the hard-packed sand, as on the more exposed beaches of 

the south shore. 

The sands are derived from the breaking up of the crystalline pebbles or bowlders of the 

drift. The till contains much more of such material than the stratified drift, and the magnetic and garnetiferous sands on the beaches appear to be no. more abundant in the vicinity 

of the till than elsewhere. This, however, may be due to the fact that most of the till bluffs 

stand in more exposed positions, where the wave action is sq strong that the sands are washed 

away, leaving only the heavier cobbles and bowlders on the beach. Few beds of magnetic sands 

were observed on the south side of the island, owing.to the general absence of crystalline mate-

.rials except near Montauk, but they are reported on Fire Island Beach off Patchogue. The 

most conspicuous deposits seen in the course of the present field work. were near Orient Point 

.and between Wading River andl\1iller Place. The individual beds shift considerably in position 

during each storm, but the general distribution of the sands probably remains fairly constant, 

the present localities closely agreeing with those recorded by Mather in 1838 to 1843. In the 

early days the sands were collected for a forge in Connecticut. 

In order that the magnetite and garnet may be separated from the quartz grains, a thorough 

·stirring of the sand seems to be necessary. The adv~nce and retreat of the ordinary· small wave 

simply produces a surface film of the heavier magnetite and garnet grains without forming a 

bed. The sand must be churned up to a considerable depth by wave after wave before any 

considerable amount is separated, hence the beds are usually formed only in time of storm, a 

·fact·which als.o accounts for their high position on the beach. 

WIND DEPOSITS . 

. 

CHARACTER AND GENERAL DISTRIBUTION. 

Although not covering areas· so extensive nor reaching heights so great as those· of some 

·other localities along the Atlantic coast, the dunes of Long Island are at many points a con-

,spicuous local.feature. They have received attention from.a number of writers, beginning in 

. 1822 with Timothy Dwight/ who in speaking of the Shinnecock Hills described them as bare 

·dunes still drifting with the winds. Drifting sands near Brooklyn were mentioned by John 

Finch 2 in 1824. W. W. Mather 3 described the dunes of the island in detail in his three reports . 

.-Elias Lewis 4 published in 1876 a detailed discussion of their composition, manner of accumu-

:lation,. distribution, and size. John Bryson 5 in 1891 referred the dunes of Easthampton to 

deposits of subglacial streams. 

The dunes in process of formation at the present time, with iew exceptions, are limited to 

the immediate vicinity of the beaches. ·At Easthampton, however, dune sands occur for a distance-of l! miles from the shore, and there is also a considerable area in the interior of the island, 

between Patchogue and Port Jefferson~ where wind action has been active in the past and is 

observed locally even at .the present time. 

The dune sands consist almost entirely of fine quartz grains, well rounded, and little stained ... 

by iron. Some garnet and magnetite and ·here and there grains of other minerals occur, and 

minute fragments of shells are not rare. The magnetite sands are sometimes rather conspicu-

. ous on .the sand surfaces after a long-continued period of winds with velocities just sufficient to 

move the lighter quartz ·grains but not strong enough to transport the heav~er magnetite. 

1 Travels in New England and New York, vol. 3, 1822, p. 317, 

2 Am. Jour. Sci., 1st ser., vol. 7, 1824, pp. 31-43. · . 

3 Rept. New York Geol. Survey, vol:.l, 1837, pp. 61-95; VOl. 2, l838, pp. 121-184; Geology ofNe\v York, pt. 1, 1843, pp. 3o-33. 

• Pop. Sci. Monthly, vol. 8, 1876, pp. 357-363. 

5 Am Geologist, vol. 8, 1891, pp. 188-190. -· .. -·- . -- .. 
•• 

RECENT SERIES! 181 

The dunes generally rest on a black loamy soil zone, if they are of recent formation, or on a 

brownish oxidized zone from which· the organic matter has been lbached, if they are among 

the older dunes. 

DUNES AT NAPEAGUE BEACH. 

N apeague Beach and vicinity constitute the most conspicuous dune area on the island. 

Five miles long and nearly 2 miles wide it comprises little but irregular sand heaps from 10 to 

30 feet or more in height, between which are many small marshes fed by the fresh waters caught 

by the dunes. Leading westward from. N apeague Harbor is a large fresh marsh, half a mile 

wide, lying between the dunes of N apeague Beach on the south and Promised Land on the 

north. The dunes reach their greatest development just east of the harbor, where they have an 

elevation of 100 feet. It is possible, however, that a part of this height is due to Manhasset 

materials, which may underlie them. The dunes of N apeague Beach 'have d~rived their 

materials n1ainly from shore wash from the east; those east of N apeague Harbor seem to have 

been supplied mainly from the same source with relatively little additions from the north side, 

their accumulation taking place mainly under the action of the southwest winds. It is believed 

that a part of the n1aterial of the dunes of Promised Land has had a sin1ilar source, being 

blown from the south coast by southwest winds, and that a part has come from the shore 

immediately to the west. The big marsh between the dune areas does not, however, convey 

the in1pression of having been crossed by a n1oving mass of dunes, and it is possible that very. 

little of the material has come from the south. 

DUNES AT EASTHAMPTON. 

In the main the dunes of the south shore are confined to a narrow fringe along the beach, 

but at Easthampton the drifting sands have progressed a considerable distance from the seashore, typical dune -topography west of the town being recognized as much as 1 t miles inland, 

or as far north as the railroad. The sandy character of the roads indicates that the' area of drifting sand probably has extended considerably north of the railroad and westward to and beyond 

Georgica Pond, although this is not conspicuously shown by the topography. East of the town 

the dunes take the form of broad bare hills with wind-swept surfaces· and hoppers. West of 

the town the dunes, though not so large, show an even more marked dune topography, the sharp 

ridges and knobs being especially conspicuous. This area is now being covered with summer 

r~sidences, and the dunes are largely under control. 

DUNES OF THE GREAT SOUTH BEACiHES. 

The barren beaches which extend along the south coast for nearly 90 miles are lined throughout their length by more or less strongly developed dunes, generally 15 or 20 feet in height .. 

Along the inside of the outer beach the dunes form a rather uniform and continuous though 

somewhat notched ridge some 20 feet in height and extending for miles along the shore. On 

the inside of this barrier there is also very commonly a second ridge, which, however, is low.er 

and less continuous than the outer one. Between the two there is generally an area of lower 

and flatter dunes mnong which are scattered knobs; many rise to a height of 20 or 30 feet. 

Between the ridges or among the low intermediate dunes many fresh-water marshes are found. 

Some of these n1erge with the salt marshes which line the inside of the barrier. The finest 

development of dunes seems to be on the Fire Island and Rockaway beaches, although the 

Rockaway dunes, as well as the once conspicuous dunes on Coney Island, have been much 

modified by human agency. · DUNES AT SHINNECOCK HILLS . 

. The SP,innecock I-Iills are composed of the Manhasset formation, in which, in this. area, 

sand predominates. In the past this sand has often been taken up by the winds to form dunes; 

and to this action a part o~. the irregular surface topography of the hills is due. A hundred 

years ago n1uch of the surface was composed of drifting sands/ but now the sands are mostly 

under control, although a little drifting still takes place. 

1 Dwight, 't:imothy, Travels in New England and New York, vol. 3, 1822, pp. 283-3313. 
182 GEOLOGY OF LONG ISLAND. 

DUNES OF THE NORTH COAST. 

Practically every bluff section along Long Island Sound shows a layer of dune sand at the 

top, and some small valleys are filled with it, as near Woodhull Landing northeast of Miller 

Place. Usually this sand is only 2 to 5 feet deep, but some of the dunes are conspicuous hills 

from 50 to 100 feet high. They all rest on an old soil zone marking the horizon of the original 

surface (Pl. VIII, B, p. 34). Where the dunes are of relatively recent origin the zone is represented not only by the usual oxidized band but by bands of nearly black vegetable mold 

as well.· 

On this side of the island the dunes are ·best developed between 'Baiting Hollow and Northville, north of Riverhead, where they ~orm a high and nearly continuous ridge more than 8 

miles long. They rest in part on the edge of the Manhasset terrace or. on the~ low moraine 

that traverses this locality. This coincidence of po~ition with the drift ridge has led to the 

classification of the entire ridge as moraine, but as a matter of fact the moraine is rarely more 

than 10 or 20 feet thick and in many places is represented by only a few scattered bowlders. 

·The great· mass of the ridge in this vicinity is composed ·of sand. Plate VIII, A, shows the 

profile of the ridge usually classed as morainal, here over 50 feet in height, and Plate VIII, B, 

shows that in reality it is a ridge of dune sand resting on the Manhasset terrace. 

Many parts of the dune ridge are very old, so that the humus of the underlying·soil zones 

has been entirely leached out: Much of its surface is covered with forests. Elsewhere, however, the dune is still in process of formation. W. W. Mather 1 in 1843 recorded the local 

deposition of several feet of dune sand in a few hours during a storm in 1836. Jacob Hill, 

northwest of Mattituck, was once much higher than Coopers Hill (Mattituck I-Iills ~) east of it, 

but the sand has bloWn. off until it is now lower. Some arable land has been covered and a 

cedar tree has been buried. Elias Lewis, jr.,Z in 1876, stated that a farm near Baiting Hollow 

had loet 30 acres by the encroachment of the dunes in 30 years and that 100 acres in all had 

been recently covered. 

Another important dune area is at Horton Beach, near Southold, where the shore back of 

the beach is lined with dunes of moderate size. Though more or less covered with trees the 

sand is still blowing. 'There are several small fresh-water marshes among the dunes and a 

pond is inclosed between the drifting sand and the bluffs. 

DUNES IN THE INTERIOR OF THE ISLAND. 

In the western half of Long Island most of the surface deposits consist of fine gravels and 

coarse sand, both of which are in places somewhat loamy. No distinct evid~nces of dune 

formation have been observed in this region. Farther east, however, the surface deposits are 

finer and there are considerable stretches where nothing but fine white sand is seen in the roads. 

The fineness and looseness of the surface coating and its apparent lack of indications of aqueous 

stratification suggest that it is of dune origin, although there is little distinct topographic 

evidence of wind action. From Coram eastward· sands perhaps of dune origin are common 

both on the plains and over the moraines. The part of the moraine south of Riverhead and 

southwest, south, and southeast of Sag Harbor is especially characterized by such sands. In 

most places they were formed before the region was forested. 

Very large areas of similar sandy surfaces lie north and northwest of Patchogue and between 

Patchogue and the morainal ridge. · 

The moraine and the plains south of it are covered with forest or brush, and few evidences 

of wind action were seen. At the north base of the ridge near Selden, however, and at points 

eastward to Coram, westward to and beyond New Village, and northward halfway to Terry-

.ville not only does the surface consist of fine sand but there were in 1903 many· spots free 

.from trees and almost free from vegetation, showing a subdued dune topography. Some low 

sand hillocks and hoppers are being formed at the present time (Pl. XXVI, B). It is believed 

that this region was once forested and protected from the winds, as otherwise the dunes would 

t Geology of New York, pt. 1, 1843, p. 31. 2 Formation of sand dunes: P·op. Sci. Monthly, vol. 8, 18iG, pp. 35i-3G3. 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 82 PLATE XXVI 

A. UNDERMINED PEAT ON COAST NEAR PROSPECT POINT, MANHASSET NECK. 

B. SEMIDUNE SURFACE IN INTERIOR OF ISLAND, NEAR SELDEN. 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 82 PLATE XXVII 

A.. 

·- B. 

MUD CONES MARKING ORIFICES OF SPRINGS IN MUD FLATS NEAR DOUGLASTON. 
RECENT SERfES. 183 

be 1nuch more strongly developed. The opportunity for the present wind action to arise is 

thought to have been given by the destruction of the forests and the vegetable mold of the 

soil by the fires that repeatedly passed over the region. What the ultimate results· will be 

can not now be foretold, for the conditions appear to be very nicely balanced. If the fires 

continue and the barren patches become larger so that they are no longer protected by the 

surrounding forests, the wind action may again become important and the dunes grow larger 

and more destructive. If, on the other hand, fires can be kept out, vegetation will·soon cover 

the burns and restore the forest to its supposed former unbroken state. 

MARSH DEPOSITS. 

FRESH MARSHES. 

Marshes of the south shore.-Along the entire south coast of Long Island, except near 

Montauk, the plains slol)e gently seaward at a rate of 10 to 20 feet to the n1ile. There are 

aln1ost no streams on tliese plains, except near the coast, all the rainfall entering the porous 

sand and making its way seaward as ground water. Near the places ·where the plains reach 

sea level this water emerges at the surface, converting the edge of the plains into a marsh extending with hardly an interruption from Coney Island to Islip, a distance of nearly 50 miles. Farther east similar marshes, although not entirely continuous, occur at short intervals to Shinnecock Bay. The landward edge of the marsh. is usually a luxurious meadow, which grades off 

":ith an interming~ing of fresh and brackish water vegetation into a salt marsh, yielding great 

quantities of salt hay. The en,tire marsh may be a mile or more wide, although a width of a 

quarter of a 1nile is more common. The relative widths of the fresh and salt portions depend 

on the relative slopes of the land surface and the bottom of the bay, one or the other preclomintl.ting according as one or the other slope is the gentler. The amount of ground water entering nt a given level also has an important influence on the width of the fresh marsh. 

Marshes in the valleys of the south side.-Where the plains of the south side of the island 

are not cut by valleys the water emerges from the lower edge of each plain, but where valleys 

are present the ground-water level i~ cut at some distance from the coast, and considerable 

volumes of water .emerge aloil.g the valleys, forming extensive marshes and even streams of 

some size. .Such a marsh is found in nearly every valley of the south shore, extending a mile 

or so back from the ·coast in the shorter valleys and several miles in the longer ones. The 

\viclth is usually under a quarter of a mile. The principal streams bordered by marshes include 

Cornell Creek, south of Jamaica; Valley Stream; the stream east of Lynbrook; :Meadow Brook, 

ne'ar Free1>ort; Jackson Creek, near Wantagh; Massatayun Creek, near Massapequa; Carlls 

Hiver, near Babylon; Connetquot Brook, near Islip; Patchogue Creek and Swan River, near 

Patchogue; Carmans Hiver, near Yaphank; Forge H iver, neat Moriches; and a number of smaller 

streams farther east. The most extensive marshes are along Peconic Hiver, stretching froll! a 

point west of Manorville to and beyond Hiverheacl, a distance of more than 10 miles. The 

only stream of notable size on the north side is the Nissequogue, near Smithtown. This is 

bordered by marshes for about 3 miles above its mouth. · 

Marshes near artijicial ponds.-There are a number of artificial ponds and reservoirs along 

the south side of the island, as at Valley Stream, northeast of Lynbrook, and near Freeport, 

Wantagh, and Massapequa, and a few built for developing power or for other purposes at points 

in the interior of the island, as between Babylon and Wyandanch. · There are two such ponds 

at Hi.verheacl. The effect of clamming the streams is to back the water up over the gently 

sloping valley floors and create marshes or swamps. This is notably the case at Hiverheacl, 

where the slack water extends upstream for some miles, forming considerable marshes. 

].farshes in obstructed channels.-Some of the c;>ld channels, espe~ially in the eastern half 

of the island, were obstructed. bY' drift left by the ice in an advance after their formation, and 

surface waters. have accumulated .behind the obstructions, forming ponds or marshes. Grass 

Pond, northwest of }.1anorville, is a particularly good example of such an accumulation. Another 

is found in the valley 1 mile west of }.1icldle Island, and still another in the valley north of this 
184 GEOLOGY OF LONG ISLAND.-

point, although these marshes are not so extensive as Grass Pond. Other examples may be 

seen at many points. About 11 milea northwest of Lake Ronkonkoma is a series of marshes in 

a channel seemingly obstructed by wash from a tributary valley. 

Marshes in kettles.-Besides the marshes in obstructed channels, or kettle channels, as 

· some of them may be called, there are numerous irregular kettles occupied in whole or in part 

by marshes. These are too numerous to mention singly, practically every kettle that con~ 

tains a pond also having a marsh around the whole or a part of its margin, and marshes are found 

also in many others in which there is no open water. Among the ponds bordered in part by 

marshes may be mentioned Lake Ronkonkoma; Artists Lake, near Middle Island; Long and 

Grass ponds, between Wading River and Manorville; Swan and other ponds near Manorville; 

the ponds south of Riverhead; and Poxabogue and other ponds near Bridgehampton. Many 

marshes· unaccompanied by ponds occur in kettles in the vicinity of Manorville and Bridgehampton; these have never recei.ved names. 

Marshes behind beaches.-Beaches have been thrown up across many of the reentrants of 

-the north shore by the waves and currents, and behind some of these fresh waters have accumulated and replaced the salt marshes that originally existed there. The fresh marshes of this 

type appear to have been more extensive formerly than at present, for fresh-water peats con-: 

taining stumps and prostrate tree trunks are found beneath the present salt marshes at many 

points, a condition apparently due to a relatively recent sinking of the land. (See pp. 212-216.) 

This probably explains why most of the marshes at the present time maintain communication 

with the salt water through narrow breaks in the barriers. In such places the fresh marshes 

are found only around the edges. · 

Interdune ·17U1rshes.-At many places on the south coast, especially on the great beaches, 

the dunes occur in either scattered hillocks or more or less definite ridges, between which are 

level areas of moderate size. Tl:tese areas usually lie a foot or two above high-tide mark but 

commonly have no surface-drainage connection with the sea, being, in fact, inclosed basins 

surrounded by dunes.. Receiving not only the rain falllli.g upon their surfaces, but also the 

seepage from the surrounding dunes, which absorb practically all the rainfall reaching them, 

these areas are naturally kept in a damp state very favorable to marsh growth. Marshes 

formed under such conditions, in fact, occur almost everywhere in the dune areas near sea level, 

such as those of the south coast. The largest single example is the marsh between N apeague 

Beach and Promised Land, on the South Fluke. Especially good examples can also be seen 

on Fire Island Beach, and minor marshes are to be found on nearly every spit and beach. They 

are absent from the dune areas of the interior, both at Easthampton and between Patchogue 

and Port Jefferson, where the depressions are·well above the ground-water level. . 

SALT MARSHES. 

Marshes of the south shore.-Inland from the edge of the fresh marshes, at a distance depending ·on the slope of the surface and the amount of seepage emerging, there is a change fro~ 

fresh to salt water vegetation owing to contact with the waters of the ocean. Outward from 

this line, to open water the marshes are for the most part salt meadows. Similar though less 

extensive marshes are built out from the inside of the great south beaches throughout their 

length.of more than 75 miles. These marshes are almost entirely of the salt-water type, although 

some are bordered with fresh-water vegetation supported by seepage from the dunes. 

An interesting feature of the distribution of the larger marginal marshes on the south 

coast is their limitation to the region west of Islip. This is due to a difference in the topographic character of the shores. West of Islip the average slope of the plains is much less 

than east of it. From Jamaica Bay 'to Islip the 20-foot contour line is from 1 to 2 miles back 

of the inner edge of the marsh-that is, the slope i~ from 10 to 20 feet to the mile and meets 

the water at a very low angle. East of Islip, however, the 20-foot contour is in many places 

only a few rods or a quarter of a mile from· the shore, although locally retreating for a mile or 

more, and the surface meets the water at a higher angle or even as a low bluff-a condition 

that is unfavorable for marsh growth. The difference in topography is due to differences in 

the geologic history of the deposits, those west of Islip belonging to the gently sloping outwash 
.. 

I 

SUMMARY OF GEOLOGIC FEATURES • 185 

from the Wisconsin glacier, whereas considerable portions of those east of Islip belong to the 

older, higher, and partly ero.ded Manhasset formation. 

Marshes of the south-shore bays.-Besides the marginal marshes just described, large areas 

of·marsh have been built up from the bottoms of the shallow bays of the south shore. None 

of these bays are more than 6 miles wide and most of them are much less. They are all very 

shallow, 11 feet being the greatest depth in Sbinnecock Bay, 10 feet in Moriches Bay, and 25 feet 

in Great South Bay. The depth of 25 feet is found only in the tidal channel at the inlet, the 

ordinary depth being not more than 11 or 12 feet. Statements were made by Elias Lewis 1 

in 1877 and by Warren Upham 2 in 1879 that channels connecting with the land valleys could 

be traced across the south side bays, but an examination of the charts seems to show that the 

few channel~ present are in no way connected with land valleys but are the direct result of 

tidn1 scour near the present or former inlets. · 

The marshes begin to form wherever the water is shallow enough for. eel grass to obtain 

a foothold, usually a foot or two below low-water mark, and where no st.rong currents are 

flowing. The dead grass and the fine silt entangled with it gradually accumulate until the 

ground rises well above above low-water ;mark and m~rsh grass takes root upon it. The up building continues until the marsh reaches a level covered only by ·occasional high tides. Part of 

the present salt marshes may have resulted from the advance of the sea over former fresh 

1narshes or swa1nps, with the substitution of a salt-water for a fresh-water fauna. At the 

east end of Great South Bay, north of Long Beach, and in Jamaica Bay, where the water was 

originally very shallow, the marshes have taken possession of the greater part of the space 

inside the beaches, having a width in places of nearly 5 miles. They· are not absolutely contiill,.IOUs, howe-ver, but are cut by many narrow and winding channels and here and there by 

more open spaces, such as Middle and East bays, near Jones Inlet. 

W. W. Mather, 3 who gave considerD.ble attention to these features, says: 

I have been credibly informed that the gra.ss now grows on a marsh near Rockaway, where vessels have floated 

within the memory of my informant. On Coney Ishnd also Mr. John Wyckoff informed me that many places which 

were ponds and pools within his recollection now produce good crops of grass. A very aged man also recollects having 

seen the surf roll in at the foot of the upland north of the marsh toward the east end of Coney Island. A broad marsh 

now intervenes betwem; the upland and the beach. · 

In fact, the whole line of geologic evidence shows that with a few local exceptions the 

marshes are being rapidly extended along the south shore. " 

The marshes on the whole are rather stable when. once formed and are seldom ·subjected 

to much erosion, except where the waves. break through the beaches and obtain access to them. 

Marshes of the north-shore reentrants.-The formation of salt marshes in reentrants on the 

north shore differs in no essential particular from the formation of marshes in the more extensive waters of the south shore already described except that more of them have probably 

resulted frmn the comparatively recent incursion of the sea over fresh-water accumulations. 

They may be seen at many points. On the side toward the Sound they are usually bordered 

by a barrier beach, but on the side toward the bay the beach is ·usually absent. Their transition 

to fresh marsh has already been described. 

SUMMARY OF GEOLOGIC FEATURES, BY LOCALITIES. 

Owing to the fact that many of the deposits are in the present report considered in detail 

for the first time, it has seemed desirable to bring together at one-place the available facts 

pertaining to each formation, making the discussions stratigraphic rather than geographic. 

This has been done under "~tratigraphic geology." Unfortunately by this method the dis- -

cussion of adjacent localities may be found on widely separated pages. Supplementary 

geographic discussions are desirable but would involve too much repetitiqn. An attem.pt 

. has been made, however, to meet the needs of geologists and others interested .in particular 

regions by preparing the following tables, which summarize the chief points of geologic and 

physiographic interest. 

1 Am. Jour. Sci., 3d ser., vol. 1:~, 1877, pp. 215-21G. 2ldem, vol. 18, 1879, pp. 81-92. a Geology of New York, pt. 1, 1843, -p. 17. 
186 GEOLOGY OF ·LONG ISLAND. 

To facilitate reference, the topographic and geologic maps are divided into rectangles 

by lines of latitude and longitude, these rectangles being designated from bottom to top by 

letters, and the columns of rectangles from left to right by numbers. The letters and nti.mbers 

make it easy to determine quickly the points of interest in a particular locality or on a particular 

trip, and the page references make it practicable to look up details with the least possible loss 

of time. 

It should be borne in mind, however, that inasmuch as 10 years have elapsed since the 

observations were made, few of the sections will be found exactly as described, especially 

those along the north shore. Here, although the outcropping edges of the formations seen 

in the bluffs often appear nearly horizontal, in reality many of the beds dip at high angles to the 

south, as may be seen by comparing b, figure 97 (p. 110), and c, figure 95 (p. ~10), the former 

being a section at right angles to the face of a bluff and the latter section parallel to the bluff 

face. Under such conditions a bed that appears horizontal where the face of the bluff is para~el 

with the strike may appear notably inclined where the bluff makes an angle with the strike, or 

· broadly arched where the coast line is curving. In many places it was impossible to determine the internal structure, and. the greater part of the figures in the present report represent 

only the apparent structure as shown in the bluffs. Where the dips are high, the c_utting back 

of. a bluff as little as 5 feet will change the whole- appearance of .a section, and it is not to be 

expected that any particular feature will b~ recogpizable after the lapse of a few years. 

Principal points of geologic interest on Long Island. 

Coordinates Part on of sec- Locality. Features. 

Plates I tion. a and II. 

lA ..... lB ...• 2A .. .. 2B ... . 2B .. .. 2B .. .. 2D ... . 3A .. .. 3A .. .. 3B ... . 

-~,~:::: 

3C .... . 3C ... .. 3C .... . 3J? .. .. 

3D .. :. 3D ... . 3D .. .. 3D .. .. 3D .. .. 4B .. .. 4B .. .. 4C .... . 4C .... . 4C ... .. 4D ... . 

NE. . . West of Coney Island. .. .. .. Sand spit and dunes ........................... , .................................. . E ..... Near Fort Hamilton ........ Harbor Hill moraine, beginning of "inland scarp" ....................... · ......... . N. . . . . Near Coney Island. . . . . . . . . . Beach dunes and max;shes ............... · ......................................... . C, S ... Southeast of Brooklyn ...... ~utwashf!om ice_alo~!? Harbor Hil,I, moraine ..................................... . N ..... Near Prospect Park......... arbor Hill morame inland scarp ............................................ .. N .......... do ...................... Confluent fans of outwash from ice along, Harbor Hill moraine .................... . SE.... On shore of East River...... Fordham gneiss outcrops . 

~w~~~ ~~~"i~i~~~~---. ~:::::::: ~~~1~~~ ~F~~;g::S~h~~~~~i~~:<:;):_: ~ :::::::::::::::::::::::::::::::::::::::::::::: 

SE .... Jam~ica Bay................ Extensive salt marshes in process of formation .................................... . W. . . . Bergen Beach............... Outwash outliers ................................................................. . NE... Near Remsen Landing ........... do ........................................................................... . S ...... Near East New York....... Outwash from ice along HarbQr Hill mnraine ..................................... . C ..... Near Brooklyn Reservoir ... Harbor Hill moraine (till type), "inland scarp" .................................. . N..... . .. . . . .. .. . .. .. . . . . .. . .. .. . . .. Wisconsin till; traces of Manhasset formation ..................................... . SW. . . ! mile northwest of Stein- Drumloidal hill •................................................................... way. 

S'V ... Near Lawrence Point ............ do ...................... : .................................................... :. E..... ! mile east of College Point.. Light-gray micaceous Jacob sand ................................................ .. E..... Near Tallman Island........ Drumloidal hill .................................................................. . S ............................. : ...... Wisconsin till and retreatal outwash .............................................. . S ...... Flushing Bay ............... Pre-Wisconsin valley enlarged by Wisconsin ice ................................. .. SE.... Far Rockaway.............. Rockaway ridge (Herod gravel member of Manhasset formation) ................... . N... . . .. .. .. . .. .. .. . .. .. . . .. .. . .. . .. Emergence of ground waters, fresh and salt marshes ......................... : . ... . S...... Near Jamaica South......... Depression between outwash plains. 

C ..... North of Jamaica ............ Till of Harbor Hill moraine; "inland scarp" ...................................... . N ................................... Thin till over modified surface of Manhasset formation ............................ . S...... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Thick till, including some Montauk till member of Manhasset formation, with occa4 D .... W .... Near Whitestone Point .... . sional exposures of gravet of Manhasset formation. . 

4 D .... E ..... Elm Point ................. . r~~~~d~~ra~~pc~!~~ceo~-clay: :: :_:: ::: :_:: ;: ::::::::::::::::::::::::::::::::::: re- lSConsm valley, modified by WJSconsm ICe ................................. . Double line of beaches (Far Rockaway and Hicks). 

4 D .... SE .... Little Neck Bay .......... .. 5B .... S ................................... . 5B .... C .................................. . Rockaway ridge (Herod gravel member of Manhasset formation). Faulted pebbles in pits. 

5 C..... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Outwash plains from ice along Harbor Hill and Ronkonkoma moraines; out,\·ash 

channels. · 5C ..... NW .. . Northwest oi Creedmoor ... . ·5D .... S .... .. Lake Success ............... . 5D .... S .... .. ~mile northeast of Lake Suc- cess. . 5D .... S .... .. Southeast of Manhasset .... . 5D .... S ..... . North Hempstead .......... . 

Harbor Hill moraine; ''inland scarp" ...... : ..................................... . Largest kettle in till or mixed moraine ........................................... .. Outwash channel through moraine, crossing of Harbor Hill and Ronkonkoma 

moraines; eastern limit of unmodified "inland scarp." . · · Bowlder 54 by 40 by 16 feet reported .............................................. . Bowlder 40 f~et long, 20 to 40 feet wide, and 10 to 17 feet high reported; possibly same as above. 

Page of 

description. 

1i7-180 

53,168 

184 

173 

53,158 

36-37 66 178-180 

115 

185 

169-170 

169-170 

172-173 

34-35,53 

115, 158-160 

161 

161 

108 

161 

Map. 

44-45 

118,127 

183,184 

34-35,53 

158-H\0 

158-160 

lil-172 

69 

44-45 

127 

166-176 

53,158 

40 

164,175 

171-172 

171-172 

5 D. . . . C .. . . . ~ mile east of Thomaston.. .. Cretaceous sand in railroad cut. . .. . .. .. .. . .. .. .. . .. .. .. .. .. .. .. .. . .. . . .. .. .. .. . .. . 69 5 D. . . . W. . . . North of railroad, Great Beginning of characteristic Manhasset plateau (100-foot level); exposures of Herod 31, 125, 135, 152 

Neck.. gravel, Montauk till, and Hempstead gravel members of Manhasset formation, in 

bluffs (rather poor). 5 D.... NE... Manhasset Neck. . . . . . . . . . . . Manhasset plateau (180-foot level) projecting· knobs of possible Mannetto gravel. .. . .5 E .... SW ... Base of Plum Point ......... Jacob sand in floor of abandoned pit ............................................. .. 5 E.... SW... ;I; mile east of Plum Point.... Knob of contorted Jacob sand in old gravel pits ................................... . 5 E .... SW, .. Barker Point ................ Montauk till member of Manhasset forlllation between Herod gravel member and 

Hempstead gravel member. 

5 E. .. . S...... '!'om Point.................. Gravel of Manhasset formation, folded by Wisconsin ice ......................... .. 5 E .... S ...... ~mile north of Tom Point... Large sand delta of Wisconsin age, fine fore and top sets ................. · ......... . 5 E .... S ...... No.rth of Port Washington .. Many pits of Herod gravel member of Manhasset formation ...................... .. 

a Center is abbreviated C. 

30 

108 

108 

135 

210 

177 

125 
SUMMARY OF GEOLOGIC FEATURES. 

Principal points of geologic interest on Long Island-Continued. 

Coordinates Pmt on ofsoc- Locality. Features. 

Piutcs I tion. 

and !I. 

5 ]~ .... Scarp between high and low level Manhasset plateaus (from Port Washington Harbor to Mott Point). · 5 E .... Montauk till member of Manhasset formation in bluff; undermined and submerged 

S ...... Northeast of Port Washing- ton. C..... Prospect Point ............ .. peat. 

Bright-colored Cretaceous clays; Maimetto gravel.. ............................... . Upturned Cretaceous and Mannetto gravel, 80 feet above sea level (on road cross- 51~ .... SE .... ~milosouthofM:ottPoint ... 5 E .... SE.... 1 mile south of Mott']>oint ... 

D~~t~eg~a~h~~~ ~:~~-t~-~~-- ..... · ............................................ . X ~L: :: ~'v::: ~~~~~;~nfsi~~~~~--:::::::::: Outliers of Manhasset formation(?) ............................................... . 613 ..•. c ................................. .. Emergence of ground water: fresh and salt marshes ............................. o••• 

6B .... N .................................. . GC ..... All ................................ .. ~~~~:S~~~~~to~~:~\~~~is; ioa~ ·patches. ~eseillbiing. ;'ialliesb;;r"i ioaill·,; · 

6 D.... S W ... · Ncar East Williston ........ . of New Jersey. · · · · Clay pit in Montauk till member of Manhasset formation(?) ...................... . 6D .... S .................................. .. Mixed outwash from icc along Ronkonkoma and Harbor Hill moraines; outwash 

channels; morainic outliers; H.onkonkoma moraine (interrupted type). Kettle plain between moraines; remnants of Manhasset formation(?) ............. . Terraced outwash channel from gal? in moraine ................................... . Harbor Hill moraine; traces of modified" inland scarp" (2~ miles southwest) ....... . Highest point on FJ.arbor Hill moraine; possible traces of 1\lannetto gravel. ....... . Gravels of Manhasset formation beneath moraine ................................. . 

(l D .. .. 6D .. .. uD .. .. ()]) ... . . . (i D .. .. s,c ............................. : .... . W .... East of H.oslyn ............. . W. . . . Southwest of Roslyn ....... . W .... Harbor Hilt. ............... . W .... West'of Harbor Hill ........ . (iD ... . C ..... East of Harbor Hill ........ . Outwash chmmel through moraine ............................................... . (j]) ... : NW ... West side of Hempstead Harbor. , 6 D .•.. NW ... Near Glenwood Landing .... 

Montauk till member of Manhasset formation, between Herod and Hempstead grav~l members, finely exposed in many gravel pits. 'l'races of Cretaceous clays and sands near landing and southward; Jacob.sand knob 

in floor of gravel pit near landing. NW ........ do ...................... Local development of lower Manhasset plateau (100 foot) ......................... . E ..... Northeast of Old Westbury .. Hills of Mannetto gravel (with Wisconsin mantle) ................................ . Nl~ ................................. High-level Manhasset plateau with semimorairial mantle of Wisconsin drift.: ..... . NW... Bar 13each.. . . . . . . . . . . . . . . . . Fine sand pit. N'V ... Hempstead Harbor ......... Pre-Wisconsin valley enlarged by Wisconsin ice .................................. . SW ... West of Sea Cliff ............ Cretaceous white sands and Mannetto gravel in bluff .............................. . SW... South side of Mosquito Cove. Cretaceous sand and Mannetto gravel in unconformable contact in gravel pit ..... . S ...... East of railroad ............. 'Deep, sM.rp Vineyard erosion valley in Manhasset formation ..................... . C, SE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . High-level Manhasset plateau (180-200 feet) ....................................... . W ... , Near G!on Cove Landing •... Montauk till member of Manhasset formation; yellow, pink, and black Cretaceous· 

clays, both north and south of landing. W .... Near Red Spring Point ...... Gray Gardiners clay with small quartz pebbles ................................... . W .... Near Weeks Point ...... : ... Gardiners clay, Montauk till member of Manhasset formation, etc ................. . N ..... Southeast of Lattington ..... White a~d pinkish ?retaceous clay in pit ......................................... . N..... Coast........................ Connectmg beaches, low-level Manhasset plateau ................................. . 

~:::::: :::::::::::::::::::::::::::::: ~:tf!e:rn~~t-s:.~~~~: ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: 

GD ... . GD .. .. 6D ... . 6 D ... . G D ... . 61~ .. .. 6E ... . 6E .. .. 61~ ... . (lE .. .. 

6E ... . 6 ]~ .. .. 6E ... . 6E .. .. 7 13 ... .. 7 B .... . N ................................... Lobate outwash margin; emergence of ground water; fresh and salt.marshes ...... . 

~!~:::: ::::::::::::::-:::::::::::::::: . g~~v~~l~~t~~~~a~~~~l~: ~-~~ ·.:::::::::::::::::::::::::::::::::::::::::::::: 

7 B .... . 7 c .... . 7 D ... . C..... . . .. . .. . .. . .. . .. .. .. .. . . . . . .. . Ronkonkoma moraine, partly on Mannetto gravel. .............................. .. W.... South of Wheatley.......... Old erosion forms in Mannetto gravel, mantled by Wisconsin drift •................ 

~\r~ ~o~~rh~~~~r\irook~;iiia.· _-_-:: ~:~~~l~Nt ~~tr'::~~-~~~~~~s_-.-.-.-::::::::::::::::::::::::::::::::::::::::::::::::: 

7 D ... . 7D .. .. 7D ... . 7D .. .. SW ................................. Dissected Manhasset plateau (Vineyard erosion) .................................. . SE .................................. Harbor Hill moraine ...•.........•.••............................................. 7E ... .. 7 E ... .. C ...... Near Oyster Bay ............ Numerous flowing wells. 

~-,,, ·. ·.: .rt:W/~ o~~~t- ~~. ~~~~~ :~~~: : ~:~~~~t ~l~i~tfe~,~~l}d~~ass-et. piaieai;. · ·cretace~-~ ~-utcrop -i~ ~aiiroact ·cui: : : : : 

NE.. . West of H.ocky Point........ Connecting beach ................................................................. . NE ........ do ..................... Cretaceous clays in beach. Gardiners clay and Montauk till member of Manhasset 

formation in bluff~. 

Cretaceous thrown out in dredging .harbor ........................................ . Jacob sand in beach; probably members of Manhasset formation (Herod gravel, Montauk till, and Hempstead gravel) in bluff (poor exposure). 

~--·:::: ~;~/~-~~~-~~~-c-~:: ::::::::: Egg~l! ~~~v~g~:;~r:~~~~~~:~eic~~::::::::::::::: :::::::::::::::::: :~::::::::: C ...... :Massapequa Hiver.......... ])epression between Hempstead and Babylon outwash plains; outwash channel. .. N ..... Noar Farmingdale ........ ; .. Cretaceous clays in larJ(e pits ........ · ............................................. .. N ..... ! mile wost of Farmingdale .. · Terrace of gravel of Mil.nhasset formation; outlying hills of Mannet1o gravel. ...... . NE ... 1~ miles east of Farmingdale. Westerly member of"Melvilledoublechannel" ................................... . NE. . . Southeast of Farmingdale... Extramorainal kettles of doubtful origin ......................................... . SW... 1! miles southwest of Plain- Depression between outwash from ice along Ronkonkoma moraine and compound view. outwash on the west. 

71L .. . 7 E ... .. 71L ... 7 E .... . 7 E ... .. 

7 E..... NE. . . ~ 1nilo south of Rocky Point. 

7 E..... E. . . .. Coopers Bluff ............. .. 

sn ... .. 8H .... . sc ... .. 8C ... .. sc .... . 8C ... .. sc .... . 8 D .. .. 

Bethpa~ ................... Cretaceous clays overlain by ~eudotill (?)in clay pits ............................ . 

~~~~!a~:~~~~~~~ie·,~-- ~ ~::: ~:;~tc~ae ot~~:ho~g~~':t~1 <;:o~~~~~~~~::t~~ab:{e.'.'. ~::.:::::::::::::::::::::: 

SD ... . 8D .. .. 8 D .. .. s ..... . SE .. .. c .... .. North of Plainview .......... Hills of Mannetto gravel; pre-Wisconsin erosion topography ...................... . Mannetto Hills.............. Mannetto plateau; sharp erosion gullies on margins ............................... . 1 milo west of Melville....... Road<;ide section of Cretaceous c1ays, marl, etc ................................... .. Southwest of Melville ....... Western of Melville "double channels" ........................................... . 

SD ... . 8D .. .. 8D., .. 8D .. .. 

c .... .. .1~ . ... . E ... .. E .... . S D ... . NW .. . ! mile southwest of Wood- Double moraine separated by flat outwash ........................................ . bury. · 8D .... N ..... HighHill ................. .. S D.. .. N. :.. . N oar High Hill ............. . Highest point of Ronkonkoma moraine ........................................... . Possible example of simple morainal cone; indications of Cretaceous or Mannetto 

core(?). Fine development of rough gravelly moraine. 

8 E..... SW. . . Northeast of Syosset ....... . 8 E.... S..... Ncar Cold Sprmg Station ... . 

8 E ..... SE ... . 8 E ..... S .... .. SE ..... W ... .. 8E ..... W .... . SE ..... W ... .. 

2 miles east of Cold Spring ... It mile<> oast of Cold Spring .. t mile south of Coopers Bluff. 

Coopers Bluff .............. . West shore of Cold Spring Harbor. 

Kettle ~lain ...................................................................... . Deep 'ineyard erosion. valley in Manhasset formation; much Wisconsin drift on sides; some post-Wisconsin cutting. 

~:~~~lM-lfl·~~~~~~~~~~~~eCiY.~::::::::::::::::::::::::::::::::::::::::::::::: White sandy Cretaceous clay ..................................................... . See 7 E (E). Cretaceous sands and clays (opposite village of Cold Spring Harbor) .............. . 

8 E ..... W .......... do ....................... Pre-Wisconsin valley shaped by Wisconsin ice .................................... . S E..... NW... South of J,Joyd Beach....... Cretaceous clays, Montauk till member of Manhasset formation, etc., in old pits •... 8 I~..... NW .. ~ South base of Lloyd Beach.. Mannetto gravel in hills·'· ....................................................... .. 8 E ...... NW ... North base of Lloyd Beach .. , Cretaceous, Mannetto gravel and Gardiners clay in bluffs (poor exposures) .. : ...... . 

187 

Pa~cor 

descnption. 

31 

13~xJr~ate 

69,83-84 69 

180 

30 183-184 

36,37 

37,48,173 

141 

37' 48, 30, 165 

43,114 49 53,168 

82,170 116 

175 

135 

69,108 

31 

30 

30 

44-45 

31J69 81 

208 

30 

69,135 

96 96,135 69 31,178-179 

177-182 

184-185 36,183-185 

37,48,173 36-37 

163-166 82 

43 

168 

30 

168 

96 30,69 

178-179 

70,96,136 

70 

108,~1251 

13u, 15:.l 178,180,184 

36,183 173 

72 82,118 

49,175 

43-44 49 

72 

118 

49 44-45,82 

30 

72 49,175 33 

32,164 

32 

43 208-212 

42-43 

170 

70 

' 70 

44-45 70 

83 

70 
188 GEOLOGY OF LONG ISLAND. 

Principal points of geologic interest on Long bland-Continued. 

Coordinates 

on Plates I 

and II. 

Part 

of section. Locality. Features. 

--------------------------------------------l-----~---------------------------------------------------1 

BE ••••. N ..... WestNeck •................. BE ••••. NE ... HuntingtonHarbor ........ . BE .•.. NE ... West side of Huntington Harbor. B F ..... SW ... Lloyd Point ............... . B F..... SW... 1 mile south of Lloyd Point. B F .•... SW ... ~ mile southeast of Lloyd Point. 

B F ..... SW ... 1 mile southeast of Lloyd • Point. 8 F ..... SE .... 1~ miles northwest of East 

Fort Point. 

8 F ..... SE .... Northwest of East ·Fort 

Point. 

8 F ..... SE .... East Beach ................ . B F ..... S ...... Lloyd Neck ................ . 

913 ............ ·•••••••••••·•••••••••••·••••• 9C .......................................... . 9 C..... E..... 1~ miles southwest of Bel- mont Pond. 

9 C ... ~ . NE . . . Carlls River ................ . 

9D .... SW ................................ . 9 D. . . . S...... Northeast of Colonial Springs 

9D .... SE .... NearWyandanch .......... . 9 D. . . . SE.. . . H miles north of Wyandanch 9 D. . . . C.. . . . Half Hollow Hills .......... _ 

9D .... W ... . i mile east of Melville ...... . 9D .... W ... . 1 mile northeast and 1 mile 

9D ... . NE .. . 9E ... . sw .. . 9E ... . 9E ... . ~~~::: 9E ... . E .... . 9E ... . E .... . 

east of Melville. 

Dix Hills .................. . Southeast of Fairground ... . Northwest of Dix Hills ..... . North of Dix Hills ......... . 1! miles south of Greenlawn. 1 mile northeast of Greenlawn. 

9E .... C •.... Northeast of Fairground ... . 9E .... NW .. . Great Neck ................ . 9E .... NW .. . ~mile south of Halesite .... . 9E .... NW .. . 1 mile northeast of Halesite .. 

9E .... N .... . Centerport and Northport harbors. 

9E .... N .... . Southwest of Little Neck 

Point. 

9E .... N .... . Southeast of Little Neck 

Point. 

9F ..... SW .. . West Beach ................ . 9F ..... SW .. . Shores of Price Bend .. _ .... . 

9 F ..... W .... Eaton Point ............... . 9 F..... W. . . . t mile east of Eaton Point .. . 9 F..... W. . . . t mile southeast of Eaton 

Neck Lighthouse. 

9F .... . S ...... East Beach ................ . SE .... ~mile east of East Beach ... . C.. . . . Oak Island Beach .......... . 9F .... . lOB .. . lOC ... . S ...... Coast ...................... . lOC ... . W .... Near Babylon .............. . 

g~~::: ·:Ed.ge~~ood"."::::::::::::::::: N, C... Base of moraine ............ _ N ..... Near Dix Hills ............. _ 

lOC ... . lOD .. . lOD .. . lOD .. . lOE .. . SW ... ·North base of Dix Hills .... . lOE .. . 8'\V ................................ . 

lOE .. . S...... South of Commack ......... . lOE .. . SE .... East ofCommack .......... . 10E .. . W .... South of Larkfield ......... . lOE .. . C ..... Northofrailroad ........... . lOE .. . N ..... ······························ 10D.· .. S ...... 1 mile north of Fort Salonga. 

11 B ... C ..... Fire Island Beach .......... . 11 B . . . N . . . . . Coast ...................... . 11 C.: .. N ..... North ofrailroad ........... . 

11 c .... s ...... ······························ 11 C .... N .................................. . 

11D ... SW ................................ . 11 D . . . SE.. . . South of Smithtown ....... . 11 D... SE.... Southeast of Smithtown 

Branch. 

11 D ... C ..... Near Smithtown ........... . 11 D. . . C. . . . . i mile northeast of Smith- town. 11 D. . . N. . . . . North of railroad ........... . 11 D ... N ..... Nissequogue River ......... . 11 D ... N ..... Stony Brook Harbor ....... . 11 D. . . N. . . . . Coast ............... . 

Kettle plain of retreatal outwash on Manhasset formation ............ _._ .......... . Pre-Wisconsin valley, reshaped by Wisconsin ice ................. _ .. _._ .......... . 'rrace of Gardiners clay 1 mile north of head of harbor ............................ _ 

Fine spit .... _ .................................................................... . 1'races of Mannetto gravel in bluffs ............................................... . Evidences of subsidence (submerged bushes) ..................................... _ 

Cretaceous and Montauk till member of Manhasset formation in bluffs; big bowlder . Folded gravels of Manhasset formation (Hempstead gravel member) .............. . 

Wisconsin till and Montauk till member of Manhasset formation in contact ....... _ 

Fine spit ........................... • ............................................... . Kettle plain of re(reatal outwash on Manhasset formation ......................... . See B B. 

Outwash from ice along Harbor Hill moraine; outwash channels ........... _ ...... . Kettles of doubtful origin ................................................... _ ..... . 

Eastern of Meh·ille "double channels"; depression between outwash from ice along Ronkonkoma and Harbor Hill moraines. 

Broad Hill moraine, outwash channel in harbor. 

Cretaceous and Mannetto gravel in abandoned pits ............................... . Outwash from ice along Ronkonkoma moraine ................................... . Extramorainal bowlders near road ascending hills. · Slopes of Mannetto gravel; level top with small bowlders and shallow basins (Montauk till member of Manhasset formation). 

Eastern of Mel ville "double channels" ....•........................................ Distinct terraces of outwash from ice along Ronkonkoma moraine, standing above 

the valley outwash from ice along Harbor Hill moraine. 

Ronkonkoma moraine on Mannetto gravel. ....................................... . Kettle plain; branching kettles; ,kettle valley ..................................... . Late outwash from ice along Harbor Hili moraine ................................ _ Hills of Mannetto gravel mantled witr Wisconsin drift ........................... . Cretaceous clays in wells, etc., on west edge of hills .............................. _ . Head of Northport-Babylon outwash channel. ................................... . 

Harbor Hill moraine .................................. : ........................... . Obstructed valleys (pre-Wisconsin); retreatal outwash on Manhasset formation .. 20-foot bowlder in Wisconsin filling of Manhasset valley .......................... . White; gray, and chocolate-colored Cretaceous clays and talus of Mannetto gravel shown in bluffs at mouth of Centerport Harbor. 

Pre-Wisconsin valleys modified by ice ............................................. . 

Cretaceous dark clay and white sand in bluffs .................................... . 

Thick Cretaceous white sands and some dark clays in pits and bluff; Hempstead 

gravel member of Manhassr.t formation unconformably on Cretaceous. 

Fine spit ......................................................................... . Cretaceous clay, Mannetto gravel, Gardiners clay, and Montauk till member of 

Manhasset formation, "shown in amphitheaters along shore of Price Bend and to north: Mannetto bowlders 2 feet orcffiore in diameter. 

Spit and dunes ................................................................... . Montauk till member of Manhasset formation in bluff near lighthouse ............. . Cretaceous, Mannetto gravel, and Montauk till member in bluff .......... .' ........ . 

Fine connecting beach and low dunes ............................................. . Montauk till member in bluff ................................................ : .... . Barrier beaches, dunes, and salt marshes ......................................... . Lobate border of outwash ........................... _ ............................ . Melville and Northport-Babylon channels (Harbor Hill) .......................... . Outwash from ice along Ronkonkoma moraine (unusually fiat) .................... · Northport-Babylon outwash channel (Harbor Hill) ............................... . Confluent outwash fans .................. _ .. _ ..................................... . Ronkonkoma moraine, in part on .Mannetto gravel ... _ ........................... . Mannetto gravel beneath Wisconsin drift ... _ ...... _ ........ · ...................... . Outwash from ice along Harbor Hill moraine over Manhasset formation .......... . Bar in outwash channel. ......................................................... . Ed15e of Smithtown "driftless" area .............................................. . 'l'hick outwash from ice along Harbor Hill moraine ............................... . Harbor Hill moraine .............................................................. . Manhasset _Plateau, much dissected by Vineyard erosion ........ .' ................. . Extensive exposures of chocolate-colored and dark-gray Cretaceous clays, traces of Mannetto gravel and Montauk till member of Manhasset formation; immense 

landslides affecting cliffs for ft mile inland; landslide scarps. ('rhis is the so- . called" Broken Ground.") 

Barrier beach, dunP.~, good examples of fresh marshes among dunes ............... . Lobate outwash i.nargin ................................................ _ ......... . Manhasset formation projecting above outwash ................................... . Compound topography (Manhasset formation and outwash) ...................... . Ronkonkoma moraine (confluent cone type); small outwash fans; south border of 

Smithtown" clriftless" area. Smithtown "driftless" area: pre-Wisconsin topography .......................... . Head of Connetquot outwash channel. ........................................... . Erosil)n bluffs facing Connetquot channel; pre-Wisconsin valleys; post-Wisconsin notching. 

Manhasset formation (Hempstead gravel member) exposed in railroad cuts ....... . Esker (just north of road) extending from bottom of valley up hillside for~ mile, esta hlishing pre-Wisconsin age of erosion. 

Harbor Hill moraine ............................................................. . Pre-Wisconsin valley, little modified by ice ....................................... . Pre-Wiscons"in valley, much enlarged by ice ....................................... . Montauk till member of Manhasset formation resting on disturbed beds l,elonging to Manhasset formation (between Nissequogue River and Stony Brook Harbor). 

Page of 

description. I, 

43,176 

44-45 

97 

179 

83 

214 

136, 170-17'2 

152 

136 

179 

43,176 

173,175 

43-44 

49,175 

82 

168 

B2, 141 

49,175 

168 

42,43 

173 

B2 

71 

49 

168-170 

52,176 

172 

71 

44-45 

71 

71,153 

179 

71,B3 

179, 1B2 

137 

137 

179, 1B2 

137 

178, 1B1' 1B5 

37 

49,75 

166 

49 

36 

B2 

B2 

172,1~ 

162 

174 

168-170 

30 

56, 71, 83,137 

178, 1B1, 1B3 

37 

liB 

118 

32, 36,162 

162,20B 

175-176 

175,20B,212 

153 

116,162 

16B-170 

44-45 

44-45 

137 
SUMMARY OF GEOLOGIC FEATURES. 

Principal points of geolog·ic interest on Long Island-Continued. 

Coordinates Part on of sec- Locality. 

Plates I tion. 

and II. 

12 ]3... N..... Fire Island Beach .......... . 12 C .... N ..... Coast ...................... . 

12 D... W.... Along Connotquot River ... . 12 D ... C, E ................................ . 

12 D .. . N .................................. . 

12 D .. . N. . . . . Lake Ronkonkoma ........ . 12 D .. . N ..... Ncar Lake :Ronkonkoma ... . 12]) .. . N ..... West of Lake Ronkonkoma. 

12 E .. . S...... i mile northwest of Lake 

Honkonkoma. 

12 1~ .•• S ...... North of .Lake Honkonkoma. 

12 ll; ... S ...... 1~ miles north and i mile west of Lake Ronkonkoma. 

1:.! E. . . SE.. . . i milo north west of Lake • Grove. 

12 E ... Sll; .... Ncar Lake Grove .......... . 12 E ... C .................................. . 

12 E ... N .................................. . 

g {~:::: ~v~::: · so.t1tli.orc·mne ·Neck ·Pailli:: 

12 F .... N ..... Oldfield Point ............. . 12 F .... N ..... Setauket Beach ............ . 13 C.... S...... Fire Island Beach .......... . 13 C •... N ..... Coast ...................... . 13 n ... All ................................. . 

13 D ... 13 E ... 

13 E ... 

13 E ... 13 1" .••. 13 F .... 13 F .... 13 F .... 

13 F .... 

13 1<' •••• 

13 F ... . 14C ... . 14C ... . 

~: E::·: 

14 E .. . 14 E .. . 14lL .. 14 E ... 

N ..... 1 mile west of Holtsville ..... s ...... South of Selden ............. 

c ..... North of Seldon ............. 

N ..... Ncar 'l'crryville ............. SIL .. 'Sout;h or railroad ............ SW ... Southwest of Echo .......... 

~~::: East of Echo ................ South of Port Jefferson ...... 

w .... North of Port Jefferson ...... 

w .... West Beach ................. 

C. . . . . East Beach ................ . C. . . . . Fire Island Beach ......•.... N ..... Coast ...................... . c,w ............................... . E ..... ······························ s ................................... . SE .... Ncar Yaphank ............. . S,C ... Ncar 8oram Hill. .......... . C ..... Near Middle Island ........ . 

14 E. . . C.. . . . 2 miles southwest of Middle 

Island. 

Features. 

Barrier be!}ch and dunes ....................................................... : .. . This region is at end of extensive salt marshes (characteristic of outwash margins), and bei?inning of erosional coast line (distinction of Manhasset surfaces). Being transitiOnal the forms are hero indistinct. 

Broad Connctquot outwash channel (Harbor Hill) ................................ . 'l'hin outwash from ice along Ronkonkoma moraine; Manhasset formation controls 

the topography. Ronkonkoma moraine (low and interrupted) ..................................... . Largest kettle lake of island ...................................................... . Depressed moraine ............................................................... . 'l'erraced outflow channel leading from Jake to Connetquot channel (now dry) ..... . Shallow pond and marsh behind recent delta in old channel in Manhasset formation. 

Kettle valley ..................................................................... . Ridge iJ?- channel ................................................................. . 

Terraced kettle ................................................................... . 

·west end of great intermorainal fosse depression (shown by 100-foot contour) ..... . 'l'hin outwash from ice along Harbor Hill moraine on Manhasset formation (Manhasset controls topography). Harbor Hill moraine; dissected Manhasset plateau· ............................... . Dissected Manhasset plateau (Vineyard erosion) .................................. . Heavy Montauk till member of Manhasset formation, grading upward into Hemp- stead gravel member; big bowlder. M0~tauk till member shows in bluffs (exposures poor) ............................ . Fine spit on both sides of entrance to Port Jefferson Harbor ....................... . Barrier beach and dunes .......................................................... . Erosion outline of coast; mainly Manhasset border ................................ . Thin outwash from ice along Ronkonkoma moraine on Manhasset formation; Manhasset frequently controls topography; channels partly Manhasset, partly Wisconsin. 

Double channel (t mile south of railroad) ......................................... . Hon konkoma moraine, probably exceptionally sanely, covered with old dune sands at many points. 

Great intermorainal fosse depression; surface largely covered with old dtme sand, some local drifting at :present time; Manhasset forma~ion controls topography. Outwash topography gtves way to Manhasset formatiOn ......................... . Outwash from ice along Harbor Hill moraine ..................................... . Harbor Rill moraine (ridge type) ................................................. . Harbor Hill moraine depressed type; many immense kettles north of railroad ..... . Large gravel vit in Manhasset formation with moraine above; large bowlder (both on road to station). . · Indications of Montauk till member of Manhasset in lower part of bluffs on east side 

of harbor: dissected Manhasset plateau (Vineyard erosion). 

Cliffs of Manhasset formation overlain by one of the Wisconsin moraines; traces of 

Montauk till member of Manhasset formation. 

Old spit flanked with marsh ..... , ................................................ . Barrier beach; dunes ............................................................. . Erosional coast line, mainly Manhasset formation ................................. . See 13 D. Carmans Valley outwash from ice along Ronkonkoma moraine ................... . See 13 D. · Carmans Valley outwash with narrow channel of post-Ronkonkoma age .......... . Ronkonkoma moraine; morainal gap at Carmans River ......................... . Surface mantle of bowlders and some till-like patches (mainly Wisconsin till, possi- bly some Montauk till member of Manhasset formation). 

Kettle valley, kettle chain (branching and completely closed) ..................... . 

14 E. . . E. . . . . ~milo eas'~ of Middle Island.. Vineyard erosion valley in Manhasset formation (modified by ice and by recent erosion by Carmans River). 

14 E . . . E..... 1 mile el\:lt of Middle Island.. Kettle valley branching, partly open, occupied by Artists Lake ................... . 14 E.. . N..... 2 miles north of Middle Is- Branching kettle valleys .......................................................... . land. 

14E ... N .................................. . Thin outwash from ice along Harbor Hill moraine on Manhasset formation; Manhasset valleys and other pre-Wisconsin topographic features. 

14F .... 8 ........................................ do ............................................................................ . 14 F .... SE .... 1 mile soul;• west of Rocky Numerous deep branching kettles and kettle valleys ............................. . Point. 

14 F .... SE .... 1 mile southeast of Rocky Tlll-eovered monadnock rising above outwash (morainal?). 

Point. 

1 

14 F ..•. C ..... North of railroad ..... ' ....... Harbor Hill moraine resting on Manhasset formation; Manhasset topography distinct on north side, many valleys being only partly obliterated by the 

moraine. Manhasset terrace well developed east of Hallock Landing. 

14 F.... W.... l mile east of Woodhull Poor exposure of mottled buff to gray Gardiners clay ............................. . Landing. 

14 F .... W ..... ~ mile east of Woodhull 

Landing. 

14 F .... C ..... ~mile west of Rocky Point 

Landing. 

14 F .... C ..... i milo west of Rocky Point 

Landing. 

14 F.... C..... l mile west of Hallock Landing. 

14 F.... E..... 1 mile ea.st of Hallock Landing. 15 C.... N.. . . . Fire Island Beach .......... . 15 D ... \V ................................. . 15 D ... E .................................. . 

15 E ... S .................................. . 15 E ... C, N ............................... . 

15 E ... I NW ... Northwest of Ridge .... ' .... . 

'!'hick, gently folded beds of Herod gravel member of Manhasset formation ........ . 

Small exposure of tough brown Gardiners clay ................................... . 

Salmon-eolored micaceous clay belonging to the Gardiners clay or the Jacob sand .. 

Upturned clays along fault plane (Gardiners clay or Jacob sand). Folded beds of 

Herod gravel member of Manhasset formation. 

Bowlder 25 by 10 feet, embedded in beach ........................................ . 

Barrier beach, dunes, margin of Manhasset formation bordered by marsh (tmusual). 

Carmans Valley outwash with narrow channel of post-Ronkonkoma age ......... . Manhasset formation with thin outwash from ice along Ronkonkoma moraine 

(local). 

Ronkonkoma moraine; morainal gaps and depressed moraine .................... . Manhasset surface with· thin till or mantle of bowlders; deep Vineyard erosion 

valleys .. Kettle valley systems ........................................................ :: .. . 

189 

Pa~o.of 

descnption. 

178,181 

175-176 

168 

165 

40 

165 

47 

183-184 

42-43 so 

40-41 

48 

•172 

30,168 

30 

137-138 

138 

179 

177-178,181 

212 

48-51,172 

50 

165 

48 

168 

172 

170 

40,170 

170,172 

30,138 

137 

184 

177-178,181 

212 

168 

168 

165 

162 

42,43 

46 

42,43. 

42 

172 

172 

42 

116,170 

97 

1_26 

97. 

97 

98,126 

172 

177,181 

168 

172 

165 

16:! 

42 
190 GEOLOGY OF LO~G ISLAND. 

Pri?"fcipal points of geologic interest on Long island-Continued. 

Coordinates 

on· Plates! 

and II. 

Part 

of section. Locality. Features. 

15 F .... S ................................... See 15 E (Ck N). · 15 F.... SE.... 1 mile southeast of Wading Branching ettle-valley system (deep pond) ...................................... . River station. 

15 F.: .. SE .... 21W~~~~~h:n~tofWading ..... do ............................................................................. . 

15 F •••. C ..... 1~ miles west of Wading Bowlder (20 by 20 by 16 feet) near highway through moraine ...... · ............... . Hivel' station.· 

15 F •.•. C ..... i mile northwest of Wading Bowlder (20 by 18 by 15 feet) near edge of marsh ............................. .' ... . River station. 

15 F .... W .... t mile east of Woodville 

Landing. 

15 F •... C..... Coast ...................... . 

15 F •... E ..... Near Herod Point ......... . 

16 D. . . S. . . . . Moriches Bay .............. . 16D ... N .................................. . 

16 D... N.. . . . North of East Moriches ..... 

16E •.. S ..... '····························· 

16 E ... C ..... South of Manorville ........ . 16 E . . . E . . . . . 2 miles east of Manorville .. . 16 E.. . N.. . . . Along Peconic River ....... . 16 E ... NV/ ................................ . 

16F .... S .................................. . 

~~~:::: ~~~~~: ~o~~[h~~e~!o~~"o;i<i.La~d:· ing. 

16 F .... C ..... Along coast ................ . 

16 F .... C ..... Coast ...................... . 

16 F... . W . . . . Paine Landing ............. . 

16 F . .' .. C ..... Hulse Landing ............. . 

16 F ..... E..... East of Fresh Pond Landing. 

17D ....................................... . 17 E ... S .................................. . 17 E... W.... 2 miles north of "Rock Hill". 

17E ... C .................................. . 

17 E... N..... South of railroad ........... . 

17 F .... S .................................. . 17 F .... C .................................. . 17 :F .... W .... Near Baiting Hollow ....... . 17 F.... N..... Along coast ................ . 17 F .... N ..... Coast ....................... . 

17 F .... N ..... Near Friars Head .......... . 

17 F.... N. . . . . t mile east of Roanoke 

17F ... . 18 D .. . '18 E .. . 

18 E .. . 18E .. . 

Landing. N ..... Near Roanoke Point ....... . N .................................. . 

S ................................... . 

C ..•... ······•·•·······••······•••··· 

N ..... ······························ 

18 F .... C, S ................................. . 

18 F.... N. .. . . Along coast ................ . 

18 F .... N ..... t mile west of Jacob Point .. . 18 F .... N ..... Ncar Jacob Point .......... . 

18F .... N .......... do ..................... . 

18 F ... . 19D ... . N ..... Ncar Luce Landing ........ . N. . . . . Hampton Beach ........... . 19 E ... . S ...... Coast ...................... . 19 E ... . S ...... ······························ 19 E .. . c .................................. . 19 E ... . C. . . . . Tiana Creek ................ . 19 E .. . 19 E ... . ~w·. ~: ~~~e~?C:o~::~ ~: ·.••• ~:::: ·:: 

19 E .. . NW... Red Cedar Point ... ~ ....... . 19 E .. . N..... 1 mile east of Southport .... . 

19 E ... N ..... 2 miles east of Southport ... . 19F .... NW .................... : ........... . 19 E... N..... Mattituck Inlet ........... .. 19 G ... SE ................................. . 

19G ... SE .... Alongcoast ................ . 19 G... SE.... Near Oregon Hills .......... . 

Old brickyards and clay pit, probably in Gardiners cl_a_y and Jacob sand; uptumed 

Jacob sand in ravines; Montauk till member of l\).anhasset formation overlies 

clay pits. 

Landslips along bluffs and fresh-water pools along beach, both suggestive of 

Gardiners clay and Jacob sand beneath talus; many deep ravines and amphitheaters; magnetic and gametiferous sands on beach. 

Horizontal beos of Herod gravel member, overlain by Montauk till member of 

Manhasset formation. · Barrier beach; erosion coast line; estuaries of pre-Wisconsin age .................. . Manhasset plain and valleys; local outwash from ice along Ronkonkoma moraine 

(largely near moraine). 

Local patches ofloam, resembling "Jamesburg loam" of New Jersey ............. . Ronkonkoma moraine; depressed moraine at gaps (locally); compound type of 

morainal ridge. 

Morainal outliers ................................................................. . Exceptionally heavy morainal development ............•........................ :. Peconic hh,er fosse_. ............................................................. . Modified Manhasset surface with thin outwash; large kettles, kettle valleys, kettle 

chains, etc. Manhasset surface with original drainage but slightly obscured; thin outwash near moraine and elsewhere. 

~~ftl~b~fi~e:~k~~fe ~;;~~::::::::::::::::::::::::::::::::::::::::::::::::::: 

Harbor Hill moraine rapidly diminishes; partly removed by sea; almost disap- pears at Jericho Landing; development of dunes at top of bluff and along north 

face of moraine becomes important. 

Fairly clean blutfs commonly showing from 50 to 90 feet of Herod gravel member 

of Manhasset formation; many amphitheaters; some landslips and springs sug- gesting Gardiners clay or Jacob sand near beach level. 

Montauk till member of Manhasset formation exposed in upper part of bluffs; many big bowlders on beach; thick Herod graver member oJ Manhasset. 

Same as preceding; Montauk till member continues to Fresh Pond Meadows, 50 

fetlt thick in places; thick Herod gravel member of Manhasset formation. 

Thick Herod gravel member; dunes at crest of bluffs ............................. . See 16 D (S}. ' • See 16 D (N). 

Bowlder 125 feet in diameter reported ............................................ . Ronkonkoma moraine (strong development), morainal channels, cones, kettles, 

etc., of all types; Bald Hill cone. Peconic Hiver fosse; Wisconsin outwash, etc., on Montauk formation; large kettles (Great Pond, etc.). 

Vineyard erosion valleys in Manl1asset formation; kettle valleys, kettle chains, etc .. Outwash from ice along Harbor Hill moraine over Manhasset formation .......... . Numerous branching kett-les (kettle-valley type) ................................. . Harbor Hill moraine (weak development) ...........•................ 0 

••••••••••••• 

Steep bluffs cut by deep amphitheaters; dunes at crest of bluffs; many exposures of Herod gravel member of Manhasset formation. 

Typical exposures of banded and. cemented Montauk till member of Manhasset 

formation eroded into pinnacles and knife-edge ridges (in amphitheaters). U ptumed clay ( Gardiners) .................•........ ~ ............................ . 

Folded and overturned Gardiners clay and Jacob sand ..•......................... See 16 D (S). 

See HiD (N). 

Honkonkoma moraine (see 17 E~,.9); depressed moraine at broad gap ............. . Wisconsin outwash, etc., on Manhasset formation; many small kettles, pr<;lWisconsin valleys. 

Outwash from icc along Harbor Hill moraine over Manhasset formation; numerous kettles and kettle valleys; some Vineyard erosion valleys. 

Harbor Hill moraine capping M:anhasset terrace (weak development with many 

n~!~J~r ~~r~;r 2~ b~ri~ f:Ci{~ ~~~~: . ................. _ ........................... . Tough dark Gardiners clay; Jacob sand; Herod gravel member of Manhasset formation; M:ontauk till member of Manhasset formation near top of bluffs. 

Pinnacles of Gardiners clay and Jacob sand; possible Jameco gravel; Herod gravel 

member of Manhasset formation; Montauk till member of Manhasset formation, near top of bluffs. . 

~~~:fe~rt:~~a~~~s~~:~~e~::::::::::::::::::::::::: :::::::::::::::::::::::::::: 

~~~s~~~f;:se ,~::!~~t;t~~~~i~~:::::::::: ~::::::::::::::::;::::::::::::: Ronkonkoma moraine (depressed at gap) ......................................... . Late narrow outwash channel in Ronkonkoma moraine.· .......................... . Outwash from Ice along Ronkonkoma moraine ................................... . vV: iscon~in outwash on Manhasset formation; kettles; Vineyard er~sion topography. Fme sp1t .................................... :, ................................... . Montauk till member of Manhasset formation and Gardiners clay in overturned 

folds in bluffs; 'l'riassic bowlders in Montauk till member. 

Herod gravel member of Manhasset formation in bluffs ........................... . See IS F (C, S). 

Submerged kettle valley in Manhasset surface .................................... . Outwash from ice along Harbor Hill moraine on Manhasset formation; outwash 

channels near Oregon Hills. . Moraine lar~ely eroded, only low narrow ridge remaining; several important gaps .. Montauk till member of Manhasset formation (with many Triassic bowlders) in 

bed in middle of bluff. · 

Page of 

description. 

42-43 

42-43 

171,172 

170,172 

109 

56, 51,180 

126 

177, li8 

118-119,168 

172 

Hi5 

165 

165 

120 

42-43,120 

117 

42-43 

42-43 

171,182 

51, 56,126 

138 

138 

126,182 

165 

32, 42, 48, 165 

43,120,162 

42-43,117 

174 

·174 

171 

51; 126,182 

138-139 

98 

98 

165 

43,162 

1i4 

171,182 

1i2 

98,109,126,139 

98,109,126,139 

213 

177,181 

118 

121 

165 

49 

168 

43,162,208 

179 141-142 

127 

42,117 

li4 

171-172 

140 
SUMMAR.Y OF GEOLOGIC FEATURES. 

Principal points of geologic interest on Long Island-Continued. 

Coordinates 

on Plates! 

and II. 

Part 

or section. Locality. 

19 G ... SE .... Middle of Oregon Hills ..... . 19 G . . . E..... ~ milo southwest of Duck 

Pond. ·· 20 E ... SE .... Hampton Beach ........... . 20 E ... C ..... Shinnccook Hills ........... . 20 E ... W .... t mile cast of Shinnooook 

Canal. 

20 l~ . . . N. . . . . N <p~~~~st of Cold Spring 

20 ]<~ ••• SE .... Ncar Cow Nook ............ . 20 ]<~ ••• C ...... West side of Robins Island .. 

20 F .... C ...... East side of Robins Island .. 

20 l? ••. NW ... New Suffolk .......... : .... . 20 G ... C ................................... . 20 G... SW... 1 mile southwest of Cutchogue. 20 G . . . NW... Along coast ........ : ....... . 20 G ... W .... West of Goldsmith Inlet ... . 

20 G • . . N. . . . . Horton Beach .............. . 20 H... SE.... Ncar Horton Point ......... . 

2~ E ••.. N ..... : ............................ . 

21 E ... N,V ................... : ............ . 21 E . . . NE... Ncar WatcrmiU ....... : .... . 21 E . . . NW... 2 miles northwest of Southampton. 21 F .... SE ................................. . 21 F ... S \V- ............................. . NE. 

21 F .... N,V ................................ . 21 G .... S ...... WestsideofJcssup Neck ... . 21 G .... W ..... GrcatHogNeck ........... . 21 G .... NW ................................. . 21 G .... Nm ... Shelter Island .............. . 

21 H ... SW .. . Hashamomuck Pond .... : . .. 21 H ... SW .. . ! mile northeast of Hasha21 H ... s.: ... . momuck Pond. 

South side of fluke ...... : . . . 21 H ... S ..... . West of Greenport ......... . 21H ... SIL .. Shelter Island .............. . 21H ... C .... . Along coast ................ . 21H ... C ..... . Coast blufis ................ . 

211[... C...... ~ milo southwest of Rooky Point. 22 E .... N\V ................................ . 22F .... S,V ................................ . 22 F .... SW ... Scuttle Hole ............... . 22 F.... S.... . . Sagaponack Lake .......... . 

22F ... . 22F ... . 22F •... 22F ... . 22 ]~ ... . 

22 F ... . 221? ... . 22 G ... . 

22 G •... 22 G •.. 22 G ... . 22H .. . 22H .. . 22H .. . 22H .. . 22H .. . 

C ..... PoxabOh'UC Pond ........... . Sl~ ................................. . NC ................................. . NC.... Long Pone!.. ............... . N..... 2 miles southwest of Sag Harbor. 

N .................................. . NW ... Long Beach ................ . SW ... Northwest point of Hog Neck. 

NW .. . Shelter Island .............. . w ... . South of South l<'erry ...... . Ram Island~e~o ............ . Hay Beach romt .......... . Long Beach ................ . 

NW .. . sw .. . c ..... . w ... . 'l'ruman Beach ............. . N .... . South side of fluke ......... . N .... . Coast .................... '·· 

22 H. ... N ..... Bluff of Brown Hills ....... . 

23 F.... S W. . . Georgica Pond ............. . 23 F ..•. C .................................. . 23 F .... , SC .... South and east of Easthamp- ton. 23 F .... N,V ................................ . 23 F.... N..... 2 miles northeast of Hardscrabble. 

23 F .... E ..... Ncar Freetown ............. . 23 F .... NE ... 1 milenorthofFrcetown .... . 23 G ......................................... . 

23 G .... C ..... WcstofSammysBe;~oh ..... . 

23 G ... C ..... Cedar Point. SammysBeaoh. 

Features. 

Bowlder 15 feet in diameter .......................................... : ............ . Bowlder 23 by 20 by 15 feet ....................................................... . 

Barrier beach; dunes ............................................................. . Hills of Manhasset formation shoved and dragged by icc; old dune sands ......... . Old clay pit shO\ving Gardincrs clay grading into Montauk till member of Ma.nhas- set formation; Herod gravel member of Manhasset formation. 

Gardincrs clay and Montauk till member of Manhasset formation in blufis ........ . 

Irregular areas of ManhasSet formation apparently laid down around icc blocks. 

Gardiners clay, Jacob Sa.Jl~l Herod grave member of Manhasset formation, and 

Montauk till member of Manhasset formation-in blufis (generally folded); fossils 

locally. 

Mainly Herod gravel member of Manhasset formation with some Montauk till 

member. 

Outlier of Manhasset formation ...........................•........................ Outwash from iec along Harbor Hill moraine on Manhasset formation ............ . Kettle witl1 till rim ncar Mattituck highway ..............•.................... · .. . 

Narrow belt of Harbor Hill moraine (hardly forms a ricfge) ........................ . M~f~~l, some apparently Montauk till member of Manhasset formation, shows in 

Fine pocket beach backed by dunes inclosing large pond .......................... . Bluffsi apparently till from top to bottom; many large bowlders on beach; one bow dor 25 feet in diameter in water It miles east of point. Outwash from ice along Ronkonkoma moraine with margin tnmcated by sea; estuaries converted into ponds. Ronkonkoma moraine ........•.....•...............•.............................. \Vatermill pond kettle ..........•.........•........................................ Kettle with outwash rim ......................................................... . 

Manhasset formation overlain by thin outwaSh ................................... . Strongly developed Ronkonkoma moraine ........................................ . 

Deeply eroded Manhasset.formation with thin mantle of Wisconsin till ............. . Herod gravel and Montauk till members of Manhasset.rormation in bluffs ......... . Outlier of Manhasset formation with mantle of Wisconsin till ..................... . Ma.Jlhasset formation with thin mantle of outwash ................................ . Thick deposits of Manhasset formation with Vineyard erosion topography; mantle 

of Wisconsin till; fine spit at Shell Beach; bays of south side clue to presence of 

Montauk ice blocks. Small show of Gardiners clay or Jacob sand opposite Conkling Point. 

Submerged kettle valley .......................................................... . Kettle valley filled with marsh deposits (this and the one next preceding bounding a remnant of Marihasset formation, formerly an island). · Manhasset formation practically without outwash ................................ . Big fresh marsh in depression in :M:anhasset formation ............................ . Sec 21 G (NE) .................................................................... . Narrow and interrupted morainal belt~ little in shape of ridge ..................... . Bluffs mainly oftill, probably largely ~1ontauk till member of Manhasset formation; 

pavements and great heaps of bowlders on beach; some exposures of stratified 

gravels, probably Herod gravel member of Manhasset. 

Bowlder 25 by 25 by 30 feet in water .............................................. . 

Barrier beach; Ma.Jllmsset plains .................................................. . Manhasset plains with thin outwash .............................................. . Kettle valley, kettle chains, connected kettles; kettle channels, etc ............... . Estuary out off from sea by beach (depression between Ma.Jlhasset formation and 

outwash). 

Part of kettle valley .............................................................. . Outwash on Manhasset formation (outwash controls topography); loam in places .. Strongly developed Ronkonkoma moraine ........................................ . Kettles in outwash channels through moraine ...................................... . Outcrops of Gardiners clay at considerable altitudes in moraine ................... . 

'See 21 F (NW). 

Connecting beach .................................... ' ............................. . Possible Jameco gravel beneath reworked fossiliferous Gardiners clay; Montauk 

till and Hempstead gravel member of Manhasset formation. 

See 21 G (NE). Flats of thick till (Montauk till member of Manhasset formation) ................... . Islands united by connecting beaches ............................................. . Low till bluffs (Montauk till member of Manhasset formation) .................... . 

~~~tc::~e~~~~~I;fanci ~:: : : : :: :: : : : : : : : : : : ::: :: : :: : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : Manhasset formation witl1 mantle of outwash ..................................... . Moraine is a more pronounced ridge than for some distance west; blufis largelr. Herod 

member of Manhasset formation, overlain by thick till (in part Montauk till mem- ber of Manhasset formation). 

Many exposures of Oardiners clay and Jacob sand, highly folded and overlain by Montauk till member of Manhasset formation; po~ible Jameco gravel under the 

Gardiners clay. Estuary closed by beach. · Outwash from ice along Ronkonkoma moraine ............... , .................... . Dunes over outwash, till and bowlders reported to have been washed out by waves on beach. 

Heavy Ronkonkoma moraine .................................................... . Morainal gap; outwash valley; depressed moraine ................................ . 

Outwash. channel through Ma.Jlhasset formation. . Ronkonkoma moraine ............................................................ . Manhasset formation with thin mantle of Wisconsin drift; topography mainly 

Vineyard erosion, modified by Wisconsin ice; kettles. 

Montauk till member of Manhasset formation overlying folded Herod gravel mem- ber. ' 

Fine spits •..... ·-.·: .............................................................. . 

191 

Paf?O of 

descnption. 

172 

172 

177-178,181 

34-35,181 

99,127 

99 

110, 128, 145 

128 

117 

174 

174 

171 

140 

179 

172 

HiS 

166 

40 

41 

121 

166 

119 

127,142 

120-121 

120 

110, 121, 129). 

162,17\1 

42 183-184 

120 

183-184 

171 

126, 140, 171 

172 

121,178 

121 

42-43 

40 

168,172 

166 

42 

9\l 

178 

89,142 

146 

179 

146 

179,182,185 

179 

120 

126, 140, 170 

89,98 

168 

163,181 

166 

168 

166 

121 

127-128 

179 
192 GEOLOGY OF LONG ISLAND. 

Principal points of geologic interest on Long Island-Continued. 

Coordi-· 

nates Part on ofsec- Locality. Features. 

Plates I tion. 

and II. 

23 G... E..... Southwest of Hog Creek 

Point. 

Low: plain of till (Montauk till member of Manhasset formation) .................. . 

2:1 H ... NW ... Near Orient Point .......... Mainly Manhasset formation; some outwash; magnetic sands on beach ........... . 23 I. ... SE .... North side of Plum Island .. Gardiners clay; Jacob sand and Herod gravel member of Manhasset formation are involved in small folds; much till in bluffs (probably largely Montauk till mem- ber of Manhasset formation). Several faults in Herod member. 

23 L ... SE .... South side of Plum Island ... Broad plain of Montauk till member of Manhasset formation on southwest end; 

faulted Herod gravel member of Manhasset; folded Gardiners clay, Jacob sand, 

and Herod member; Montauk till member, east of Fort Terry. 

24F .... C ..... Coast ....................... Beltofdunesofconsiderablewidth ............................................... . 24 F.... N..... Along railroad............... Hills of Manhasset formation with little outwash ......... ~ ......................... . 24 F.... N. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Strong morainal ridge ..................................................... · ....... . 24 G... SW... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . General upland of Manhasset formation, with Vineyard topography; broad low24G .... SW ... A cabonack Harbor ......... . '24G .... W ....• NearHogCreekPoint ...... . 24 G .... E .... . 24 G •... E .... . Ram Island, etc ............ . Great Pond ................ . 24 G .... E .... . West side of Gardiners Island. 

landsofMontauktillmemberofManhassetformation. 

Sand spit and marshes ............................................................ . Montauk till member of Manhasset formation in folded Herod gravel member. 

Spit in process of formation, largely below sea level. ..•............................ Pond inclosed by V -shaped spit. ....... : ......................................... . Montauk till member of Manhasset formation north of Great Pond; Herod gravel member of Manhasset formation; reddish clays and clayey sands 1 mile north of 

Great Pond (Gardiners clay or Jacob sand). 

24 G .... NE ... South of 'l'obacco Lot Pond .. Jacob sand, Gardiners clay1 and Montauk till member of Manhasset formation, 

(generally folded); fossils m Gardiners clay and Jacob sand. 

24 H... S ...... East of Cherry Hill Point .... Fine section of red and black fossiliferous Gardiners clay overlain by Jacob sand ... . 24 H... S. .. . . . Southwest of Bostwick Bay. Jacob sand with ripples; Herod gravel and Montauk till member of Manhasset 

formation. • 24 H ... C ........... do....................... Fine V-shaped spit inclosing pond ................................................ . 24 H... C...... Gardiners Point............. Sandy island making continuation of Gardiners Island spit. 24 H ... SE .... NortheastcoastofGardiners Cretaceous possibly present; Jamecq gravel under Gardiner.> clay (doubtful); 

Island. Gardiners clay, Jacob sand, and Herod gravel member of Manhasset formation 

involved in complex folds. Montauk till member of Manhasset commonly poorly developed. SE.. . . Inland on Gardiners Island. . Ridges due to folding ...... : . ..................................................... . SE .... 'l'obacco Lot Pond .......... Baybar ......................•...•.....•.......................................... NW... N apea~:,>Ue Beach. . . . . . . . . . . . Big connecting beach; high dunes; fresh marsh among dunes ..................... . S ........... do ............................ do .................................•.......................................... 

24H .. . 24H .. . 25F ... . 25G ... . SE .................. :. . . . . . . . . . . . . . . Moraine (thin) on ManhaSset formation; old dunes on surface; Manhasset erosion .. SE.... Quince Tree Landing........ Montauk till and Herod gravel members of Manhasset formation .........•......... SW ... Goff Point, Hicks Island .... Hooked spits ..................................................................... . SW... Eastern Plain Point......... Herod gravel and Montauk till member of Manhasset formation ................... . 

25G ... . 25G ... . 25G ... . 25H .. . SW ... South coast ................. Thick Herod gravel member overlain by Montauk till member ................... . SW... Interior ................... :. Hills of Manhasset formation with superficial mantles of mor:ainal drift (Wiscon!!in) 

and dune sand (local). 

26 G ... . 26 G ... . 

26 G .... SW ... ! mile southwest of Rocky Intermorainal fosse channe~s ...................................................... . Point. 

26 G ... . W..... 1 mile west of Rocky Point .. 26 G ... . w .. ~ ....... do ...................... . 26G .. . C ...... Montauk station ........... . 26G ... . C...... Fort Pond ................. . 26G ... . C ...... South of Fort Pond ........ . 26G ... . C ...... Montaukstation ... ~ ....... . 26G ... . N..... South of Culloden Point .... . 

26G ... E ..... Near Ditch Plain ........... 26G .... NE ... Great Pond ................. 

27 G ... NE ... South coast ................. 

27 G ... N ..... Montauk Point .............. 

27 G ... N ..... North of Montauk Point .... 27 G ... N ..... Southeast of False Point .... 27 G .... N ..... ! mile west of False Point ... 

27 G .... N ..... 1·mile west of False Point ... 27 G .... NW ... Oyster Pond ................ 27 G .... NW ... Near Shagwong Point ....... 27G .... NW ... Reed Pond .................. 

Jacob sand under Herod gravel, member of Manhasset formation.· .. : ............... . Herod gravel and Montauk till members of Manhasset formation ................ _. .. Bay bar ............•.....•...•.•.........•.....•.................................. Pond inclosed by oay bar ......................................................... . Barrier of Montauk till member of Manhasset formation .......................... ·I 

Uplands of Manhasset formation. (See 26 G, SW.) ................................ . Herod gravel member of Manhasset formation under heavy till, possibly Montauk 

till member. 

Low plain of Montauk till member of Manhasset formation ...................... . Pond inclosed by bay bar, the latter characterized by dunes, fresh marsh, and 

ponds. 

Mainly Montauk till member, often double or triple and including stratified sands; 

several outcrops of Gardiners clay and Jacob sand; Herod gravel member of 

Manhasset occasionally seen; possibly some Hempstead gravel member of Manhasset. Sands below clays may belong to Jameco gravel. ·Thick Montauk till member·of Manhasset formation overlain by stratified gravel (Hempstead member of Manhasset). 

Folded gravels (Hempstead member or gravelly phase of Montauk till member) .. Montauk till member of Manhasset formation in .bluffs ........................... . Dark chocolate-colored Gardiners clay; Jacob sand; Herod gravel member of Manhasset formation. . Montauk till member of Manhasset formation exposed at point ................... . Pond behind bay bar ............................................................. . Montauk till member of Manhasset formation ...................................... i 

Pond behind bay bar .......... · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · : · · · · · · · · · · · · · · · ·I 

G:EOLOGIC HISTORY. 

PRE-CRETACEOUS EVENTS.1 

Page of 

description. 

142-:143 

126,179-180 

100-101,111, 

129,146 

100-101' 111, 

130,146 

181 

121 

170 

121 

179,184 

179 

1i9 

100, 129, 146 

100_~105, 

llu, 146 

105 

110,129 

1i9 

90, 100, 110, 

129,146 

35 

lii-178 

179,181,184 

179,181,184 

166, 180-181 

128,143 

1i9 

129,146 

128,143 

121 

47 

111 

128,143 

177-178 

177-1i8 

145 

121 

128 

145 

177-178, 

181, 183 

89,99,111.1 

144, 15o 

144 

156 

144 

99,111 

143 

177-178 

143 

177-178 

Little evidence is afforded ·by the older rocks of the Long Island region as to the conditions 

existing on the island in Archean and Algonkian time. The Fordham gneiss, which occprs at 

the west end of the island, is of pre-Cambrian age, but as it may be either a metamorphosed 

sedimentary bed or an igneous rock, its exact relationship can not be told. Its quartzitic 

bands, which strongly suggest sedimentary origin, are parallel to the bedding ·of the Cambrian 

rocks, and· in most places there is little evidence of· any considerable unconformity between 

1 For a full discussion of the geologie history of the New York region, see New York City folio (No. 83), Geol. Atlas U.S., U.S. Geol. Survey, 1902. \ . 
... 

GEOLOGIC HISTORY. 193 

them. At a few points, however, important breaks exist. The region appears to have been 

under water through a part of the Cambrian at least,· for a quartzite of this age is found at a 

number of points in the vicinity of New York. The quartzite is followed conformably, so far 

as is known, by the Stockbridge dolomite; indicating the presence of open water during late 

Cambrian and early Ordovician time. Similar conditions also continued without material 

break into late Ordovician time, as indicated by the conformable I-Iudson schist overlying the 

dolomite. There is no record of the Devonian and Carboniferous periods in the rocks of the 

region, and it is probable that during these periods the land was above water much of the time 

and was subjected to extensive erosion by streams. A little farther north considerable mountain 

masses were uplifted in Devonian' time and were later reduced by erosion, and it is not impossible 

that some uplift occurred in the Long Island region, although not until near the close of the 

Carboniferous was the compression of the rocks into sharp folds .(fig. 54, p. 66) finally completed. In the meantime there had been considerable igneous activity in the region, manifested 

in the intrusion of the granitic masses in the Fordham gneiss of Long Island. Some of these 

1nasses on Long Islarid are so sheared, presumably as a result of the folding, that they now 

have a decidedly gneissic structure. 

After the period of mountain. building there was a long period of erosion, during which 

the land was worn down to a low rolling surface. In the New Jersey region a shallow basin 

was gradually formed, and in late Triassic or early Jurassic time this basin was occupied by a 

body of brackish water, in which the red sandstones and shales of the Newark group were 

laid down. During the deposition ~f these beds there was a second period of .igneous activity, 

producing both intrusions and surface sheets of diabase or" trap rock," among which is the great 

mass known as the Palisades. · 

Later, in Jurassic 'time, the entire eastern part of the United States became dry land and 

was ·worn down by streams until the whole surface was reduced to a gently undulating plain, 

with a few unreduced remnants or monadnocks. · This plain, w~ch was covered with the clayey 

products of decomposition, is known as the Schooley peneplain and extended from the Atlantic 

coast over what are now the Appalachian Mountains well into the interior of the country. 

Toward the close of the Jurassic period a tilting of the plain began, the part southeast of central 

New Jersey sinking below sea level and the part northwest of it rising. 

CRETACEOUS EVENTS. 

The elevation of the land in the northwest led to a more active erosion, and the sand and 

e clayey materials derived from the decomposition of the rocks were swept seaward and deposited. 

along the coast, forming what is known as the Potomac group of New Jersey and regions farther 

south. The absence of marine shells and the presence ·of numerous leaves and other vegetable 

remains have .led to the belief that the Potomac group is a fresh or brackish water formation 

dep,)sited by meandering rivers or in estuaries or lagoons practically cut off from the sea by 

barrier beaches. Several hundred feet of the clayey deposits were laid down. The deposition 

of the Raritan formation seems t.o have been completed in the early part of the Upper Cretaceous epoch and in New Jersey was followed during the remainder of Cretaceous ti~e by the 

deposition of more or less marly sediments characteristic of deeper water and indicating a continued tilting, which eventually carried the old crystalline surface well below s~a level. When 

the tilting was completed the land in the vicinity of Schooley Mountain, in New Jersey, had 

been elevated 1,500 feet, and the surface along the Atlantic coast sloped off beneath the sea at 

the rate of 100 feet to a mile. In the Long Island region the late Cretaceous depression was 

Jess marked, clays and sands derived from the erosion of the uplifted peneplain continuing to 

be deposited while the marls were forming off the New Jersey coast. The fragments of fossil 

shells found here and there in wells or in the drjft indicate 'that the clays and. sands of Long 

Island were not all fresh or brackish water deposits, but were at least in part marine. The 

marl bed at the top of the hill near Melville (p. 68) suggests that fairly deep water covered thi~ 

part of the island at the close of the period. 

1629°-14--14 
194 GEOLOGY OF LONG ISLAND. 

TERTIARY EVENTS. 

EOCENE EPOCH. 

Although ther.e seem to have been slight interruptions in the deposition of the Cretaceous 

beds in certain parts of the New Jersey region, 1 the exposures. on Long Island are too poor -to 

admit of their recognition even if evidence of them is present. Between the Cretaceous ari~ the 

Eocene deposits there was no strong break in New Jersey, for although a slight unconformity 

exists the deposits of the Eocene and the upper part of the Cretaceous are alike in character if 

not practically continuous in deposition. Where the Eocene deposits are seen they do not 

differ greatly in thickness but occur as a practically uniform bed across the State.2 This uniformity would seem to indicate the absence of any strong unconformity, the thinness of the 

Cretaceous being due to nondeposition rather than to subsequent erosion. There is, however, 

evidence of a slight unconformity at the .top of the Eocene, but no extensive erosion of either 

the Eocene or the underlying Cretaeeous beds seems .to have oeeurred. Physiographic evidence 

elsewhere seems to indicate that the Eocene may have been marked by the completion of a 

peneplanation begun in the CretacP-ous, and that the surface stood at· a low level, land erosion 

being nearly at a standstill. 

MIOCENE EPOCH. 

At the elose of Eocene time there was a further differential tilting of the land, in the early 

stages of which the Eocene deposits may have been somewhat eroded. Later, however, the 

Coastal Plain was depressed and the sea advaneed aeross "the Eoeene and over the Cretaceous 

deposits on the west.. This depression probably eompleted the prineipal tilting of the early 

Tertiary peneplain. Over both the Eoeene and the part of the Cretaceous covered by the 

ocean the sandy beds of the Mioeene were deposited. These were thin near their western 

limit but S<?mewhat thicker seaward, burying and obliterating the erosion surface cut in the 

Cretaeeous and Eocene deposits. · EARLY PLIOCENE EPOCH. 

After the deposition of the Mioeene sediments there was a decided uplift, which raised the 

deposits above sea level and brought on a period of active erosion, which in the New Jersey 

region removed considerable portions of the Miocene beds and eut into the underlying Eocene 

and Cretaceous. 

LATE PLIOCENE (?) EPOCH (LAFAYETTE FORMATION). 

The early Pliocene was .followed generally throughout the Atlantic Coastal Plain by a period · 

of deposition during which the Lafayette formation, consisting of a mantle of sands and days o 

derived mainly from the underlying Cretaceous and other beds, was deposited over the Coastal 

Plain, even overlapping the metamorphie rocks in places· and apparently obliterating the 

topography developed in the tCa:rly Pliocene. It has usually been assumed that the deposition 

took place during the period of submergence that has been postulated by most geologists as 

occurring at this time, but Chamberlin and Salisbury 3 have recently argued that the Lafayette 

was laid down in eastward-transgressing zones of stream deposition, which filled the valleys 

and spread somewhat widely over the coastal peneplain .that had been developed in the less 

resistant deposits in Eocene and Mioeene time. The transgression they eonsider to be due to a 

moderate ''bowing'' ·of the peneplain rather than to submergence. They also supposed that 

the conditions affecting vegetation and preeipitation had an important influence on the nature 

of the erosion and deposition. _ 

It seems certain, however, whether the formation is marine or fluviatile, that the land 

could not have been far above sea level, for the widely spreading mantle of elays and sands 

could not well have been formed at its present elevation of 300 or 400 feet had the streams 

possessed the fall that this· would require between the landward limit of the formation and 

the then exis~ing coast, 'which could not have been far east <?fits present position. 

1 Clark, ·w. B., Science, new ser., vol. 4, 1896, p. 759. 

2 Clark, W. B., Correlation papers-Eocene: Bull. U.S. Geol. Survey No. 83, 1891. 

a Chamberlin, T. C., and Salisbury, R. D., Geology, vol. 3, 1906, pp. 305-3Q8. Compare views of Hill and Vaughan, Eighteenth Ann. Rept. 

U. S. Geol. Survey, pt. 2, 1898, pp. 246-247. 

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QUATERNARY EVENTS • 195 

The general absence of glacial erratics in the Lafayette has led most authorities to refer 

the fonnation to the Pliocene, but Hilgard referred the similar deposits of the Mississippi Valley 

to the Pleistocene. The granitic materials at Natchez, on which his opinion was based, have 

since been shown by Chamberlin and Salisbury 1 to rest :unconformably on the Lafayette, 

which they retain in the Pliocene. It h~s been suggested that the light sands overlying the 

known Cretaceous on Long Island (p. 80) might 'doubtfully be Lafayette, but they are destitute 

of crystalline pebbles, and this would seem to indicate a pre-Pleistocene origin. 

POST-LAFAYETTE EROSION. 

The deposition of the Lafayette formation was followed by a period of active erosion, 

during which the Tertiary and Cretaceous deposits were cut down in places in the Long Island 

· region from an altitude of about 300 feet above the present sea level to one somewhat below 

it.. The exact depth to which the erosion extended could not be determined with certainty, 

owing to the difficulty of recogniz4tg the Mannetto-Cretaceous contact from well records and 

san1ples. The Mannetto gravel (the· earliest Pleistocene deposit) is found resting on the Cretaceous down to sea level and the unconformity probably extends considerably lower. 

The northward slope of the general Cretaceous surface and the buried pre-Pleistocene 

.valleys in the Cretaceous show that a powerful drainage system existed north of the present 

island, and there is little doubt that extensive excavation took place in th·e Long Island Sound 

region at this time. The magnitude of the unconformity resulting from this erosion, which was 

many tiu1es greater than that producing the post-Miocene unconformity farther south, is the 

chief reason for placing it after the Lafayette. So far as the island is concerned, it is the only 

period of erosion between the Cretaceous and the Pleistocene of whic~ a ·record has been left. 

QUATERNARY EVENTS. 

. PLEISTOCENE EPOCH. 

MANNETTO GLACIAL STAGE. 

The earliest of the Long Island deposits that have been referred to the Pleistocene is the 

Mannetto gravel, which has been described elsewhere, and the reasons for its assignment to the 

glacial series have been there presented (p. 85). The term "Mannetto stage" is applied to the 

period of it:;; deposition. 

The large percentage of quartz and the sporadic yellowish clays in this formation are 

strongly suggestive of a derivation of the Mannetto material from the formations of the Coastal 

Plain like the Cretaceous and Miocene, or from glacial material forming a mantle of residual 

soil. Over gg per cent .of the material is probably from one or the other of these sources. The 

rmnaining fraction of 1 per cent consists of granitic pebbles and erratic bowlders, apparently, 

to judge from their absence in the Cretaceous and Tertiary deposits, derived directly or indirectly 

through some agent not acting in the earlier periods of deposition. Although it is possible 

that the deposits are strictly fluvial, it is thought more probable that glacial ice played a part 

in their accumulation, being the agent to which the peculiarities pointed out are due. 

The deposits are now found up to a maximum altitude of about 330 feet, at or near which 

extensive remnants of an old flat surface of Mannetto gravel still exist. This fact may possibly 

indicate that the land stood 330 feet lower than at present and that a broad, flat. sheet of gravel 

was built up to that level, at least in parts of the island. The slope of this surface from 330 

feet at its north ~nd to 270 feet at its south end, or at a rate of 15 to 20 feet to the mile, is 

very si1nilar to that of the present outwash plain in the same region, and the flow and 

plunge structure of the two are identical so far as can be seen. On the other hand, the erratic 

bowlders of the Mannetto have no counterpart in the outwash on Long Island, although "the 

Wisconsin ice is known to have abounded in such bowlders. 

, The slope of the old Mannetto surface and the internal structure of the deposit would favor 

an outwash origin. The evidence of the bowlders might seem to point to submergence, at 

1 Op. cit., p. 308. 
196 GEOLOGY OF LONG ISLAND. 

least enough to admit of flotation by thin ice, but transportation by floating ice·, such as might 

occur in the shallow deploying streams of an outwash plain, may readily be conceived, although 

nothing of the sort appears to have taken place in the Long Island region under what must be 

acknowledged as equally favorable conditions in Wisconsin time. It is possible that the lower 

part of the deposits in which the bowlders were found was formed below sea level, and 

that the upper part was a sloping subaerial outwash plain similar to those now existing on the 

island. The presence of the well-stratified clayey 'layers at low levels is also favorable to the 

hypothesis of partial submergence, for such clays have not been found in the later outwash 

deposits of the island and would be difficult to account for in those positions owing to the 

absence of any probable causes of ponding. (See Bridgeton formation, p. 223.) 

The Sound depression already existed in pre-Mannetto time, as shown by the Cretaceous 

topography beneath the Mannetto, but it is. possible_ that large Cretaceous deposits existed 

along the Connecticut coast and supplied much of the gravel making up the Mannetto 

formation. 

The granite bowlders are found near the bottom of tl~e Mannetto, as exposed on the island 

and granitic pebbles occur up to. the very top, hence the ice invasion began early in the Mannetto stage and continued to its close. That the period of ice invasion was long seems to be 

indicated also by the great thickness of the deposit. 

The small percentage of granite pebbles may be due to a long period of attrition beneath 

the ice or in waters near its margin, which effectively reduced most of the fragments. On the 

other h~nd, the fact that the first ice moved across an area of residual soils, where a large part 

of the materials picked up must have been disintegration products consisting largely of clay 

and quartz, with a few fresh granitic fragments, may be the chief reason for the small percentage of granitic pebbles in the Mannetto compared with the later Pleistocen~ gravels. 

The exact place where the ice margin rested is largely a matter of speculation. It may 

have halted in the Sound trough a little north of the present edge of the island. 

POST-MANNETTO INTERGLACIAL STAGE. 

The deposition of the Mannetto gravel was followed by a period of extensive erosion during 

which the formation, originally 100 to 300 feet or more thick over western Long Island, was. so 

completely reduced that only a few isolated knobs remained at the beginning of the Jameco 

deposition. The term post-Mannetto is applied to this apparently interglacial stage of erosion, 

which is well represented by the Wheatley Hills, near the village of the same name, the essential topographic expression of which, the superficial coating of till being disregarded, is due to 

erosion in this epoch. 

The highest remnant of the Mannetto surface is found in the West or Mannetto IIills, in 

the northern part of which it has an elevation of 330 feet above sea level. In the Wheatley 

Hills remnants of the .Mannetto probably occur as high as 300 feet. From this altitude, which 

appears to mark the upper limit of the formation in western Long Island, valleys were cut 

down to a point not less than 300 feet below the present sea level, the depth to which the sue-

. ceeding Jameco gravel has been recognized in wells. 

Whether the Mannetto gravel lay at a similar altitude over eastern Long Island is not 

known, but its development was probably somewhat less in this direction. Large masses, 

·nevertheless, probably existed and the fact that the deposits as a whole were eroded until only 

scattered remnants were left points to a period either of very rapid or of long-continued erosion, 

or most likely both. The elevation as estimated from the I-Iudson submarine channels, which 

are assumed to have been formed at this time, appears to have varied from 1,300 feet in the 

earlier part of the stage to over a mile in the later part (p. 60). . 

The post-Mannetto erosion presumably followed, in its broader features, the lines of preMannetto drainage, as the Mannetto gravel was probably somewhat lower over the deep Cretaceous valleys than over the Cretaceous knobs, in the same way that the Wisconsin outwash 

is lowest where the underlying Manhasset formation is low and highest where the }.1anhasset . 

is high. That this is true' in the Mannetto Hills region is shown by the section at this point 

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PLEISTOCENE EPOCH. 197 

(fig. 57, p. 81), the Mannetto and Cretaceous erosion surlaces being almost parallel. Where 

the Cretaceous relief was less marked, however, the erosion was independent of the old topography and cut indiscriminately into Mannetto and Cretaceous. This type of erosion was 

probably especially characteristic of the north-shore districts. In general, however, the land 

at the close of the post-Mannetto interglacial stage appears to have been not greatly different 

in extent and topography from that existing at the beginning of the Mannetto stage. The 

larger Cretaceous remnants appear to have been very nearly the same as before, the principadifferences apparently being the presence of a mantle of Mannettb gravel that covered and 

obscured the older deposits in places and the deeper trenching o! those deposits elsewhere. 

JAMECO GLACIAL STAGE. . 

The extensive erosion epoch just described was followed by an influx of material whose 

gra~1itic character seems to indicate a glacial source. The position of the deposits below sea 

'level and the necessity of depending on well records for a knowledge of them n1ake the determination of their exact character and structure practically impossible, and it is not definitely 

known whether or not the ice actually invaded Long Island. The high percentage of granl 

itic pebbles present locally n1ay n1ean the riear proximity of the ice sheet, but the deposits as 

a whole do not differ greatly, so far as appears from well rec.ords, from the later Manhasset or 

fro1n the Wisconsin outwash deposits, and they 1nay have a similar origin, in which case the 

ice front presu1nal;>ly lay somewhere in the Sound. The distribution of the Jameco gravel on 

Long Island and the islands east of it would seem to· indicate that the front extended along the 

Sound beyond Orient Point, passed north of Block Island, crossed southeastern Massachusetts 

(probably ~etween Plymouth and Boston), and passed north of Truro, Cape Cod. 

The deposits appear to have accumulated in part in the space between the ice front and 

the Cretaceous-Mannetto core of Long Island, and in part outside of and around the then 

existing land masses, the materials being swept westward and southward through the depression 

east of Jamaica and eastward and southward around the east end of the existing land beyond 

the Mannetto IIills. The depression of the land at this time seems to have been 150 feet or 

more (p. 218). 

The erosion by the ice in the immediate vicinity of its margin appears, if we n1ay judge 

by the relatively small amounts of quartz and other locally derived materials, much less pronounced than during the fust invasion. In fact, the almost entire absence of recognizable 

1naterial derived fron1 the underlying Cretaceous or the Mannetto gravel would seem to indicate 

either a nearly stagnant condition of the ice near its margin or a sheet so overloaded with 

material that it could no longer erode .. 

GARDINERS INTERGLACIAL STAGE. 

The J ameco gravel gives way abruptly to the Gardiners clay, as if the source o'f materials 

wos suddenly removed, as it doubtless was by the retreat of tl1e ice sheet from the vicinity of 

the island. So far as known there is no unconformity between the two formations, the lignitic, 

Inarshlike, and fossiliferous phase of the Gardiners following without any important time 

break upon the cessation of J ameco deposition. 

The land masses during the deposition of the Gardiners clay remained essentially as during 

the J a1neco deposition. No conspicuous change of level took place either. at the beginning of 

or during the Gardin~rs deposition, although there was a slow subsidence, which kept pace 

with the accumulation, the top of the forp1ation always remaining at or below sea level. The 

subsidence could have been little if any n1ore rapid than the deposition, as there is apparently 

an entire absence of locally derived materials, such as would be present if the sea encroached 

upon the Cretaceous and Mannetto land masses to any extent. The ·actual position of the 

land, to judge from the general occurrence of the clays below sea level at the present time, 

appears to have been generally a little higher than the present level, the few occurrences of 

clays above sea level being apparently due to folding. 
198 GEOLOGY OF LONG ISLAND. 

In western Long Island the clays appear to have accumulated in the form of marsh deposits 

bordering the preexisting land masses, but in eastern Long Island peat, :Qluck, and other indications of marsh origin are less common, and the nonorganic character of the bulk of the deposits 

appears to indicate an offshore origin of the formation, except perhaps of the earliest phases. 

The question whether the deposition took place during a true interglacial stage or siinply 

during a temporary retreatal stage is somewhat puzzling. The presence of fossils in the clays 

at several places indicates a period of sufficient length to permit the reoccupation of the formerly 

glacial w~ters by animal life, and although this might, under favorable circumstances, take but 

a few years, the character of the remains indicates a climate no colder than that of the Maine 

coast at the present time, hence it is probable that the ice had drawn back to the northern portion of the cpntinent, if it had not entirely disappeared. The lignite present in the clays on 

western Long ·Island and elsewhere and the general blackish color, presumably due to organic 

matter, of the same clays on the Massachusetts islands and on Cape Cod indicate that plant 

life had also extended itself over the region. The thickness of the clays themselves, taken in 

connection with their apparently slow accumulation, likewise points to a period whose length 

is more compatible with an interglacial stage than with temporary retreat. 

JACOB TRANSITIONAL STAGE. 

The fact th~t the transitional Jacob sand gives place to the glacial Herod gravel member 

of the Manhasset formation without any recognizable time break,_ and that the latter. in 

turn gives way by transition to the great Montauk till member of the Manhasset, would make 

plausible the supposition that the advent of new materials from the advancing ice sheet brought 

about the change from the marine Gardiners clay to the more quartzose Jacob sand. It is not 

unreasonable to suppose that the change of material marking the beginning of Jacob deposition 

toqk place as soon as the advancing ice front reached the headwaters of the Connecticut and 

began to discharge its drainage down the valley of that river. Under such conditions only 

the finer material would he borne to the river's mouth and distributed in the surrounding 

region. The quantity of materials, if the supposition as to origin is correct, would indicate a 

very slow advance, as the Jacob sand reaches a thickness of at least 30 feet. 

, A~though.the materials seem to be of glacial derivation, the Jacob is essentially a marine 

formation. It extends from western Long Island to southeastern Massachusetts and its persistency points clearly to marine deposition rather than to accumulation in valleys or b~sins 

above sea level; moreover, its marine fossils :fi.x its origin beyond dispute. 

Evide:r;:1ee of any material change of level is .lacking. That no considerable elevation took 

place is shown by the entire absence of any evidences of stream erosion in the deposits at this 

horizon, the only unconformities being those due to the scouring action of the overriding 

Montauk ice. · 

During the period of Gardiners deposition, as elsewhere pointed out, the land appears to 

have slowly subsided, the sinking just about keeping pace with the accumulation, as indicated 

by the fossils and salt-marsh deposits at the various horizons. 

Such marsh deposits are absent, however, from the Jacob. This fact, taken in connection 

with the persistency of the beds, the regularity of.the lamination, and the general absence of 

ripple marks, suggests a sinking of the crust and a deepening of the water. As noted on another • 

page, however, faceted pebbles elsewhere in the immediately overlying Herod gravel member 

of the Manhasset point to a subaerial accumulation of the Herod; hence it is probable that the 

subsidence was slight, possibly only a few feet, or a little more than enough to keep pace with 

the accumulation. This slight depression probably resulted in a further contraction of the land 

masses of the island, so that, except in the Mannetto, Wheatley, and Hal! Hollow hills and 

certain other parts of western Long Island, marine currents had free sweep over the region. 

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PLEISTOCENE EPOCH. 199 

MANHASSET GLACIAL· STAGE. 

HEROD GLACIAL SUBSTAGE. 

The change from the :fine simdy silts of the Jacob to the glacial gravels of the Herod member 

of the Manhasset formation indicates a nearer approa'ch of the ice that supplied the materials. 

The sttndy nature of the lower beds, the more gravelly character of the upper layers, and the 

:final transition into the Montauk till member would seem to mark various stages of the advtt~ce 

of the ice, the front possibly just reaching the Sound at the time of the earlier deposition, 

advancing close to the north shore of Long Island in· the later Herod accumulation, and 

eventually invading the island in the succeeding Montauk substage. 

The Ilerod accumulation was marked by the development of strong currents, far more 

swift and powerful than those of the Gardiners and Jacob stages of deposition. In fact, no 

clay or :fine silts could have been deposited if currents of like strength had existed during those 

stages. These currents may be regarded either as glacial streams, emerging from the near-by 

ice front and deploying over a subaerial outwash plain, or as tidal or other currents of the sea, 

according to the elevation of the region with reference to sea level. 

The Jacob accumulation certainly took place below sea level, and in the absence of any 

evidences of stream erosion at its upper contact there is almost equal certainty that it was 

not lifted ,above sea level before the beginning of the conformable Herod deposition. The 

lower beds of the I-Ierod must therefore have been deposited at or below sea level. Higher up 

in the Ilerod member, however, wind-faceted pebbles point to subaerial accumulation, making 

it seem probable that subsidence either was not going on at this time or did not keep pace with 

the upbuilding. This part of the Herod seems most likely to have been formed as an outwash 

plain similm: to those of the Wisconsin stage, though on a larger scale. The accumulation 

appears to have been very slow, the surface being exposed for long periods before being covered 

by the succeeding layer. That the surface was probably nearly or quite devoid of vegetation 

and that it was subject to strong winds, transporting sharp sand as in a sand blast, and in fact 

possessed many of the characteristics of a desert, is shown by the faceted pebbles. That these 

conditions were widespread rather than local, furthermore, is shown by the presence of similar 

pebbles at the same horizon on Nantucket and Cape Cod. 

It seems probable that different conditions prevailed toward the close of the Herod accumulation, the deposition of the overlying 'Montauk till membe.r apparently taking place below 

sea level. It would seem, therefore, that the subsidence, which started at least as early as the 

beginning of the Gardiners deposition but wh~ch barely kept pace with the accumulation in 

the Gardiners and Jacob stages, went on more rapidly during the later part of the Herod substage; so that', notwithstanding the upbuilding of the earlier deposits to some height above sea 

level and the continued rapid deposition,· the whole of the Herod was carried below sea level 

before the advance of the ice marking the close of its deposition. 

The I-Ierod member differs in thickness from point to point, as. all deposits must whose 

materials are supplied by glacial streams, but on the whole ~he member displays remarkable 

persistency and uniformity for a glacial deposit. It seems to have had the form of a single 

broad southward-sloping cuesta-like outwash plain, partly subaerial and partly submarine, 

rather than that of a series of small outwash fans. 

MONTAUK GLACIAL SUBSTAGE. 

J?IRS'l' ADVANCE OF THE ICE. 

Position of ice margin.-The ice, which was still remote at the beginning of the deposition 

of the Jacob sand, had approached nearer during the deposition of the I-Ierod gravel member 

of the :Manhasset, and it actually invaded the Long Island area at the beginning of the Mont{tuk 

substage, as indicated by the change of the deposits from gravel to till. The ice is thought to 

have reached south in western Long Island in a lobe extending down the old Jameco valley 

between Jamaica and Brooklyn, depressing the Gardiners clay beneath its weight in that 

·vicinity and giving rise to a doming at its edge, as recorded in the wells of the Rockaway Ridge. 
200 GEOLOGY OF LONG ISLAND. 

Eastward from this region the ice front, for the most part, probably rested again~t the side 

of the Mannetto and Half Hollow hills, although bowlders in the Half Hollow Hills and a structureless mass resembling till resting upon the Cretaceous in the Bethpage pits suggest a temporary 

advance extending much farther south. Beyond the hills mentioned the margin bent. to the 

southeast and passed off beyond the present coast line at a point somewhere west of the till 

exposures in the Easthampton beaches. Its invasion is marked in western Long Island by the 

bowlder bed of H~mpstead Harbor and by the bowlders and till in the wells of the exterior of 

the island, and in central Long Island by a thick bed of till. On the North Fluke its work was 

mainly erosion, but· it also laid down a ce~tain amount of till, and on the South Fluke it accomplished both severe erosion and heavy deposition. 

Erosion by the Montauk ice sheet.-The erosion unconformity at the base of the Montauk 

till member of the Manhasset formation has been described elsewhere (p. 134). It extends from 

Long Island through Block Island, Marthas Vineyard, and Cape Cod to the Maine coast or 

beyond and is nearly everywhere characterized .by evidences of drag, by ice-shoved bowlders ' 

and till deposits, or by superficial thrust faults, folds, and contortions. In fact, the evidences 

are so clear-cut and decisive as to establish without question the eroding agency as the Montauk 

ice sheet. 

The ice on its advent was strong and vigorous, as is characteristic of an underloaded 

glacier, and although it produced some folding, mainly of the open type, its work was largely 

erosion and consisted in scouring broad, shallow trenches and basins and in beveling the 

upturned beds of the arches and folds. Later its vigor· appears to have decreased, probably 

through overloading by material picked up in its earlier stage, and deposition of the great beds 

of till which are characteristic of the Montauk member followed . 

.Accumulation of the earlier deposits of the Montauk tillmember.-The evidence bearing upon 

the conditions existing during the accumulation of the .Montauk till member presents many 

puzzling features. The most characteristic phase of the Montauk is the till, and of this the 

most distinctive feature is its peculiar banding or lamination. This lamination, which is 

described in detail in another place (p. 133), is unquestionably the result of accumulation in 

the presence of water and may be conceived as due to deposition in local basins on a land 

surface, to purely aqueous deposition in the sea, to extremely rapid deposition in front of the 

ice margin by unconfined glacial waters ·above sea level, or to accumulation beneath the ice 

sheet overriding the water-saturated I-Ierod gravel member and other deposits below sea level. 

That the deposition did not take place in local land basins appears to be indicated by the 

extent of the Montauk member as well as by the absence of the necessary barriers; that it 

was not the result of unconfined glacial waters deploying upon the land is shown by the persistent character and horizontal position of the bedding, the member exhibiting neither the 

high angles of aqueous morainal accumulations nor the definite stratification that it would 

have if it were an outwash deposit; and that it does not represent marginal deposition below 

sea level is made apparent, likewise, by the absence of any well-marked ·assortment, such as 

would inevitably result from purely aqueous deposition of this nature. The member is filled 

with erratics irregularly distributed through its mass in far greater number than can be readily 

conceived as arising in any way other than by direct deposition as ground moraine beneath 

an ice sheet. The banding, however, is far more conspicuous than in any ordinary subaerial 

accumulation of till. Accum~lation beneath the ice sheet in the presence of abundant water 

appears, therefore, to be· the most probable origin' of these deposits. It seems likely that the 

lamination results from dragging a loose body of drift, obtained by erosion or from the ice by 

basal melting, and its readjustment in the presence of water. The exte~t of the Montauk 

member seems to indicate that the water was a general rather than a local feature and suggests 

that the deposits were most probably laid down below sea level. 

That the deposition of the gravel phase of the Montauk took place below sea level would 

of necessity follow if the interpretation of the origin of the till is correct, as the two have the 

same stratigraphic position, one grading laterally into the other. The angle of bedding, high 

in many places, the rapid change in direction of the dip, and the presence of delta and other 

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PLEISTOCENE EPOCH • 201 

flow and plunge structures and of contemporaneous unconformities of erosion and deposition 

are all in harmony with the assumed conditions of rapid submarine accumulation at the margin 

of the ice sheet. The bowlders, too, seem to point to an aqueous origin, for although ice-rafted 

bowlders are not uncomn1only borne clown the shallow streams of outwash plains and left in 

·the gravels, such definite and continuous beds as characterize the Montauk horizon on Long 

Island are seldom formed in that way. 

The absence of fossils,. except those of secondary origin, in the reworked deposits of the 

Gardiners clay points to shallow water. In Inglefield G'Q]f, Greenland, overlooked on three 

sides by ice caps, .abundant marine life was found by T. C. Chamberlin, who states 1 that 80 

crinoids and nun1erous more common forms were obtained from a single haul of the dredge . 

If deep water had prevailed along the Montauk margin, similar evidence of life would be 

expected; but if the water was very shallow, the quantity of silt known to have been constantly 

discharged into it by glacial streams and the rapid upbuilding of the deposits by the coarser 

material would tend· to prevent the occupation of the water by marine forms along the immediate border of the ice .. The severity of the erosion by the Montauk ice indicates that the 

depth of the water was too slight to affect materially (through its powers of flotation) the 

scouring action of the glacier. On the whole it seems probable that the Montauk accumulation 

took place in very shallow water, possibly only a few feet in depth, with perhaps numerous 

islands, due to folding, rising above its surface.· The actual depression of the land with reference to the present sea level appears to have been fro~ 75 to 100 feet. 

FOLDING DURING MONTAUK SUBSTAGE. 

Extent.-The most marked feature of the Montauk till member, aside from the deposits 

themselves, is the great folding that the underlying beds. exhibit. Tllis folding is of widespread 

distribution, being found from Brooklyn on the west to Orient and Montauk points on the 

east, as well as on the adjoining islands. East of Long Island it is developed on a large scale 

on Fishers, Block, Marthas Vineyard, and Nantucket islands and on Cape Cod and the Maine 

coast. The magnitude of the disturbance is in places very great, at least for a surface feature, 

not a few of the folds reaching a height of 100 feet and some measuring 150 feet or more. The 

'folds always present their steepest faces to the south or are overturned in that direction. 

Many of them pass into faults, almost always of the thrust type, the upthrow being on the 

north. 

The disturbances affecting the beds are of at least five orders of magnitude-(1) tilting 

affecting the island as a whole; (2) low arches several miles in diameter and extending throughout the greater part of the length of the island, such as the North and South fluke ridges and 

their extensions; (3) low flat arches several hundred yards in diameter, representing irregularities in the broader arches of the second class; (4) steep, closed folds of considerable length but 

of slight breadth, many of ·them overturned and faulted; and (5) the minor. crumplings of the 

individual layers of the sharp folds of class 4. These classes are not, of course, sharply differentiated from one another, .all gradations between them being noted. Altho.ugh the flexures 

differ in details of forn1ation, all except those of the first class appear to have been the result 

of the sa1ne general agency, the nature of which is considered in the following paragraphs. 

Anticlinal nature of the fluke ridges.-The anticlinal nature of the fluke ridges is brought 

out by the height of the Gardiners clay lying upon and near them. Tllis formation on each 

fluke is commonly at or slightly above or below sea level, whereas between the flukes and, so 

far as can be determined from well records, both north and south of the flukes proper or of the 

Manhasset belts (p. 119) which mark their continuation to the west its height is about 50 feet 

lower. These ridges are therefore to. be regarded as broad flexures having an altitude of about 

50 feet and a length of not less than 50 miles on Long Island,. to say nothing of their eastward 

continuations-the northern one through Fishers Island, Watch Hill, Point Judith, Elizabeth 

Islands, and Cape Cod, and the southern through Block Island, Marthas Vineyard, and Nantucket. 

1 Personal communication. 
202 GEOLOGY OF LONG ISLAN:p. 

. These broad flexures are riot simple arches but compound f<?lds or anticlinaria, being 

characterized by both minor local warpings and sharp, overturned folds and faults. The main 

warping affected all the Pleistocene· formations and extended down iJ?.tO the underlying Cretaceous beds, as shown by the occurrence of the latter in many places along the axis of the arch 

farther east, as on Block Island and Marthas Vineyard. The minor warpings probably affected 

all but the lowest of the Pleistocene accumulations, but the.sharper and smaller folds and the 

faults are still more superficial, the disturbance becoming rapidly less downward and in many 

places disappearing entirely, even in the cliff sections. It is doubtful if the beds lying 50 feet 

below the surface are much if any disturbed by even the more pronounced folds. 

Possible causes of the flexures.-Reaching down into the Cretaceous, the disturbance could 

have been produced only by an agency of great power. Crustal warping at once suggests itself 

as this agency, but thsre are many reasons against accepting it as the real cause. If the two 

flukes and their prolongations were part of a single uplift, the arching would be of a magnitude 

that would make the theory of crustal warping seem somewhat reasonable, but as a matter of 

fact the arches, though long, are relatively narrow, their extent transverse to the axis being 

apparen'tly far less than is to be looked for. in true crustal warping. Their occurrence in two 

groups, separated by a broad undisturbed area, points to a repetition of local causes rather than a 

general cause such as crustal warping. It is believed, the!efore, that such warping, if it played 

any part in the formation of the anticlinal ridges, was merely a subordinate agency. On the 

other hand, it seems equally certain that the ridges have resulted from causes differing also from 

those that produced the minor folds. They are too broad, low, and flat (some being several 

miles wide and only 50 to 100 feet high) to have resulted from 

.----:::o-"""""""---:::o---===--..--,-_---.,i., tangential thrust, and furthermore the deposits consist of incohe-

'\: rent sands, clays, and other material entirely incapable of trans-

~ mittillg thrust. 

/': That the anticlinoria are due to a warping of the surface in 

"" : their vicinity seems c~ear, but that they were mainly the result of 

: ·a general crustal warping is very doubtful. It is more likely that 

: they are due chiefly to a warping of the unconsolidated deposits I 

.__...;:;::---:::; __ -=---==:;-=--------:!c' through agencies other than crustal movements. 

FIGuRE 198.-Diagram illustrating com- Sediments vary greatly in bulk according to the arrangement 

pression of beds through rearrangement or "packing" of the component grains or fragments. Being deof grains. posited without application of external pressure and exerting 

only about two-thirds of the pressure of their normal weight (owing to the buoyancy of the 

water) 'the particles of the sediments are at first very loosely arranged. As the deposits thicken 

they may undergo someJeadjustments.leading to a decrease in bulk, but they remain far below 

their maximum density. 

If the fragments were spherical they might be arranged (1) so that the lines connecting the 

centers of adjacent spheres would form re~tangles, as shown by a-a-a-a in figure 198; (2) so 

that the connecting lines would form rhombs with an acute angle of 60°, as a-a-b-bJ· or (3) 

so that the lines would form rhombs intermediate between the rectangle and the 60° rhomb. 

The first arrangement gives the maximum and the second the minimum vertical thickness. If 

the grains of a sedimentary bed were originally deposited in the first manner and were subsequently forced by pressure to rearrange themselves into the second form, there would be a 

shortening of the vertical space taken up by the grains, represented by 

2(r-r cos 30°) =2 r(1-cos 30°) =0.268 r. 

The last factor is the equivalent of 13.4 per cent of the thickness of a given deposit 

(d-d', fig. 198). Ifit is assumed that the original thickness of the Pleistocene deposits before ' 

the folding was 300 feet and that in the original deposition the fragments took an arrangement 

equivalent to the one first described, then if by the pressure of the ice their arrangement was 

later changed to the second form, there would have been a compacting of the deposits that 

reduced their thickness about 40 feet. 

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PLEISTOCENE EPOCH. 203 

Of course, it is doubtless true that the grains never possessed as ~whole the arrangement 

suggested, but .observations on soils show that the grains may be far fron1 uniformly in contact 

with one another, ·many vacant spaces occurring nmong them. The application of pressure 

would be even more likely to close such spaces than it would to rearrange the grains. 

Actual tests on natural silts and sands, the properties of which may be taken as indicating 

the arrangement of the grains, show that although the average theoretical pore space is only 

about 30 per cent and the highest theoretical pore space only 47.64 per cent of the volume, the 

actual porosity/ as indicated by the water absorbed (which may amount to 50 per cent of the 

weight of the material 2), is sometimes.as high as 75 per cent~ Pressure applied to such material 

could not fail to produce a very considerable compacting, probably fully equal to the theoretical 

amount due to the rearrangement of the grains. Experiments made on gravel under the 

writer!s direction in 1912 showed that a pressure of 10 pounds to the square inch, corresponding roughly to the weight of 10 feet of J?laterial, resulted in a reduction of 5 per cent in the 

volume of the gravel tested. Higher pressures, up to, and including 100 pounds, gave 1 per 

cent additional compacting .. 

In the rearrangement of grains just described the decrease in vertical thickness is not the 

only result. Figure 198 shows that this decrease in thickness is accompanied by an increase 

in lateral exte;nt. This increase (c-c'), which is equal to the radius of the grain, is not cumuJative, however, being the same in a horizontal distance of a mile- as in a fraction of an inch, 

hence it can play no part in the warping. · · 

It is well known, however, that clays flow readily under relatively slight pressure, as has 

been brought out many times by the movement of clays beneath even relatively low dams and 

railroad embankments. The long ridges of mud forced up on each side of the railroad fills 

recently built across a wide stretch of Great Salt Lake and the flow of the clays underlying the 

Gatun Dam at Panama are cases in point. The likelihood of such flow is now universally 

rec~gnized by engineers, and in all important constructions great precautions are taken to. avoid 

building upon clayey materials. If the flow is so pronounced in 15 to 20 foot embankments, it 

must have been much greater under t~e pressure of hundreds of feet of ice. The deposits over 

which the ice sheet passed were unquestionably saturated with water and the clays and fine 

sands, which when wet flow like quicksands, must have been very plastic. It is not improbable, 

therefore, that flowage toward ~he anticlinoria! axes actually took place on a considerable 

scale, as it is known to have occurred in small degree in the case of some·. of the minor folds. 

The lateral flow of the clay mn.y be conceived to have taken place either with or without an 

accompaniment of folding. Flows accompanying folding may be seen at many points on 

Long Islari.d and the New England islands, being manifested by the squeezing of materials 

from the compressed parts of anticlines into the parts that were under less pressure. 

N otwith::;tanding the competency of an ice sheet to materially compact the deposits which 

it overrides, the anticlinoria! ridges of the north and south flukes can not be referred to such 

an agency acting upon a uniform series of deposits. Ice overriding such an accumulation 

1night indeed compress the materials and reduce their thickness, but the result would be broad, 

even depressions stretching from the outer limit attained by the margin of the ice back to the 

hard rocks of the mainland, leaving the extramarginal deposits in their original horizontal position (fig. 199, p. 204). Such compression would, therefore, account only for the northward slope 

of the arches, as the compacting would take place only on that side of the belt, failing entirely 

to explain the equally conspicuous southward slope. In other words, the materials north of 

the flukes have not simply been depressed, but the deposits beneath the flukes appear to have 

been actually raised, as they stand materially higher than in the extraglacial region on the 

south. ' 

It may be conceived, however, that the compacting was differential rather than uniform, 

the variation in amount being due either to differences in the character of the Pleistocene 

1naterials or to differ~mces in the altitude of the underlying Cretaceous and consequently in the 

1 Slichtcr, C. S., Theoretical investigation of the motion of ground waters: Nineteenth Ann. Rcpt. U. S. Geol. Survey, pt. 2, 1899, p. 309. 

s King, F. H., Principles and conditions of the movements of ground water: Idem, p. 70. 
204 GEOLOGY OF LONG ISLAND. 

thickness of the Pleistocene deposits. There does not appear to be sufficient variation in the 

character of the Pleistocene deposits in the region to account for the abnormal difference between 

their altitude in the moraine and their level elsewhere; hence this aid to differential compacting 

need not be considered. An ice sheet moving over a region, such as that shown in figure 200, 

where porous glacial materials rest upon an irregular surface of more dense and resistant 

Cretace'ous rocks, may be readily imagined to produce a considerable warping through compacting. It must be acknowledged, however, that though this may be a possible cause, the 

information at present available, either in the surface exposures or in well records, is insufficient 

to afford any absolute confirmation. 

On the whole, squeezing and flowage of the clays appear to be an entirely competent cause 

of the" arching, the materials being assumed to have been pressed outward, or to the south, 

FIGURE 199.-Diagram showing supposed compression of beds under ice load in the Long Island region. a, Montauk ice sheet; b, Herod gravel member of Manhasset formation; c, GardinE>rs clay; d, Jameco gravel; e, Mannetto 

gravel;/, Cretaceous. 

under the weight of the ice sheet, which, to judge from the presence of ice-deposited material 

at the top of the Mannetto Hills, could not have been less than 410 feet thick at its margin and 

may have been much more. Beyond the margin of the ice the pressure would be largely 

removed and the chiy would tend to thicken and rise, lifting the overlying beds. Under this 

assumption the larger and more pronounced ridge would be formed at the outer limit reached 

by the ice, and a sm~ller ridge would be associated with a retreatal halt, for the clay would be 

less mobile and possibly thinner at the time of the halt, having already been subjected to the 

probably more severe pressure of the early advance. Although of the several causes suggested 

flowage of the underlying clays seems best to 

explain the features observed, the writer is loth 

to advocate the theory 

of a transfer of material on the necessary 

scale. At the same 

FIGURE 200.-Diagram showing supposed influence of Cretaceous masses in controlling the compression of 

the Pleistocene deposits under ice load. a, Herod gravel member of Manhasset formation; b, Gardiners 

clay; c, Mannetto and Jameco gravels; d, Cretaceous. 

-time warping and compacting seem, with the evidence now at hand, even more improbable explanations. Perhaps 

the least objectionable view is that which ascribes the origin of the arches to a number of 

agencies supplementing one another, of which crustal warping, compacting of deposits by 

pressure, and flow of plastic materials under pressure are the most important. Whatever 

the cause may be that raised the arches, it appears to have been assisted by the drag and folding 

due to the overriding ice. That the elevation of the anticlinoria has been considerably increased 

by such folding can not be questioned. In a section on Gardiners Island (fig. 80, p. 100) measuring about 1,350 feet, beds of a length of 2,500 feet have been compressed, giving rise to an 

increased elevation which, before the subsequent erosion of the folds, must have amounted to 

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PLEISTOCENE EPOCH~ 205 

at least 100 feet. On Fishers Island (fig. 85, p. 102) the original elevation due to folding appears 

likewise to have. been nearly double this amount, and on Martha~ Vineyard the thickening is 

still greater. 

. Minor warpings.-Under the head of minor warpings are included the undulations (many 

of them isoclinal), usually reaching only a few feet in height and a few hundred yards in length, 

which are seen in many bluff sections and which give rise to a large part of the variations in 

the level of the beds. In .some places warping of this particular type is more apparent than 

real, being due to the truncation of the sharper folds of the class described below along lines 

more or less parallel with their axes. There are, nevertheless, many warpings t.!:l.at are not 

assodated with such folds, and it is -the origin of these that is considered here. 

Differential settling, which, as has been seen, is likely to take place in any thic~ formation, 

especially where there are, as in the Pleistocene deposits of the Long Island region, more or less 

minor variations in composition and t~xture, doubtless took place to a certain extent under the 

weight of the deposit itself, although the warpings so produced would be likely to be very slight. 

The principal readjustment, however, was probably due to the overriding ice sheet of the 

. Montauk substage, which because of its great weight exerted a profound influence upon tp.e 

overridden beds. Its action was especially pronounced in the later part of the invasion, when 

through differential erosion ·and deposition the surface had become more or less irregular and 

the weight of the ice was unequally applied at different points. Direct shove upon the irregularities of the surface under such conditions may have been an important factor in the production of the warpings. Ice pressure against the stiffer and more clayey beds at their outcrops 

may also have been transmitted beneath the overlying gravels, giving rise to warpings at some 

points of weakness. , 

Open and closed folds.-Although differing in magnitude, the open and closed folds are of 

the same general origin and may best be considered together. They include everything from 

an undulation barely well enough defined to be recognizable as a fold to the closely compressed 

and overturned and recumbent folds. In altitude they vary from perhaps 5 feet to 150 feet 

or more and in breadth 'from a few feet to an eighth of\ a mile or more. Their a~es are generally 

parallel with the trend of the anticlinoria of the North and South flukes, of which they ,are a 

superfici~l feature, having a roughly east-west direction. Very few of the folds are symmetrical, 

almost all showing more gentle slopes on the north than on the south. Overturning, where 

present, is always toward the south. 

Orogenic movements ·were postulated by many of the early workers as the cause of folding 

on Long Island, but the evidences against such movements are very -definite. Arthur Hollick 

some years ago pointed out the superficial character of the folding and the undisturbed condition of the underlying beds. Very conclusive evidence was brought out by well records collected· 

by A. C. Veatch .during the present investigation, the logs showing the Cretaceous strata to dip 

uniformly at the rate of a few feet to the mile regardless of the disturbance of the superficial 

beds. Ftirthermore, the present field work brought to light many sections along the coast in 

which the folding could be seen dying out downward. (See figs. 98, p. 110, and 133, p. 130.) 

The slipping in mass of a bed or series of beds down a dip or structural slope may cause 

the compression of the lower part of the mass into folds which are called slip folds. The movement takes place along bedding planes, which may have been more or less tilted. The most 

favorable localities for slip folding are in basins toward the center of which the beds dip steeply, 

but it may occur also on any monoclinal slope. 

The origin of the Long Island folds and those of the New England islands farther east has 

sometimes been attributed to slip folding, the slipping movement being assume~ to have proceeded from north to south because the beds were overturned in that direction. One of the 

chief difficulties in the way of accepting such an origin is the absence of any slope adequa.te to 

cause the slipping of the beds. The present normal attitude .of the Pleistocene beds is almost 

horizontal, and the dip of the Cretaceous appears to be only a few feet to the mile, or a small 

fraction of 1°, and it is not probable that the original dips were any steeper . 

. I 
206 GEOLOGY OF LONG ISLAND. 

Slip folding would seem to be more likely to characterize the clayey beds than the more 

sandy deposits. No such difference was observed, however, the clays being no more disturbed 

than the sands. In fact, the folding is in many places greater in the sandy material at the 

surface and much less in the underlying clays. 

Slip folding would necessarily be accompanied by the production of a slip or fault plane, 

which in the present instance would have to be several miles broad and more than 100 miles 

long. That no such slip plane is present on the greater part of Long Island is unmistakably 

shown by the bluff sections, which, though reaching in places below the level of folding, nowhere 

afford indications of any but local breaks due to slipping. On the contrary the upper folded beds 

with a few minor exceptions grade downward into the lower undisturbed beds without· breaks 

of any sort, showing beyond question that the beds are in place and that the folding is only a 

superficial disturbance. Where the folding is more profound and extends below sea level it 

is more difficult to prove the absence of the slip plane, although there is no evidence of its 

existence. 

Among the phenomena associated with the folding and affording a clue to its origin may be 

mentioned (1) its maximum development along the borders of depressions, such as Long Island 

Sound and the bays between the flukes farther east, or along nort~ward-facing escarpments; 

(2) its minimum development over flat surfaces such as the upper part of the Herod gravel 

member of the Manhasset formation; (3) its usual development at the Montauk horizon and at 

that horizon only; (4) the superficial character-of the disturbance; (5) the rapid disappearance 

of the folding below the Montauk; (6) the absence of disturbance above the Montauk (except 

locally at the base of the Wisconsin till); (7) the constant association with the Montauk till 

member; (8) the evidences of drag in the incorporation of the underlying gravels into the till; 

(9) loc.al evidences of the plowing of the underlyi11g surfaces by bowlders; (1.0) the almost universal evidences of ice erosion at the Montauk horizon; (11) the massing of till against u11disturbed 

beds; (12) the association of the folding with thrust faulting on planes at high angles; and (13) 

"the overturning of the folds always toward the south. 

It is to be emphasized that the folding is everywhere associated with the Montauk ice 

inva~ion; that it is practically absent at other horizons;_ that it was most marked where 

elevations rose above the surrounding level so as to present bold faces to the advancing ice 

sheet; that it was associated with notable ice drag and erosion; and that the faulting and folding 

were always in the direction of the ice movement. -

Notwithstanding the general absence of folded beds beneath the glacial deposits of the 

country as a whole, the ·absence of any extended folding on Long Island by the Wisconsin ice, 

which reaches a thickness of more than 400 feet, and the general ease with which ice is known 

to ·override morainal and other unconsolidated deposits without material disturbance, there 

seems to be no question that it is to the ice sheet invading the region in Montauk time that the 

conspicuous folding is due. The theory accounts for all the associated phenomena, makes 

use of an agency that is known to have been at hand, and leaves nothing but its unusual vigor 

unexplained. 

The cause of the unusual vigor of the ice in the Long Island region, as indicated by the 

extraordinary disturbance of the beds over which it passed, presents an interesting problem, 

the key to which is probably to. be found partly in the thickness of the ice sheet, partly in topographic conditions, partly in the subaqueous nature of the deposition, and partly in the climatic 

conditions. The scarcity of folding in the glacial deposits of the American continent as a whole 

and its insignificant development as compared to that in the Long Island region are probably 

due largely to the general absence of scarps or other topographic forms adapted to receive the 

brunt of the attack of the advancing ice. In the Long Island region, on the contrary, the Montauk ice found opposed to its advance the thick series of gravels (Herod gravel member) previously deposited at its front. Against these it impinged with great force, bending, folding, 

shoving,· and faulting them on a grand scale, the disturbance involving also the underlying 

clays, especially in the later stages of the advance, when consider3:ble portions of the gravels 

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PLEISTOCENE EPOCH. 207 

had been eroded. Similar conditions likewise .prevailed in the region between the flukes and 

along the South Fluke. . I 

It is true that, notwithstanding the even more marked scarps opposed to the Wisconsin 

gln,cier, the folding it accomplished was much less than that due to t~e Montauk ice. Probably the greater effectiveness of the Montauk ice was due largely to the greater thickness of 

the glacier and to the greater vigor of its movement. 

That the Montauk ice was thicker than the Wisconsin in the Long Island region seems to 

be indicated by the fact that it reached a more southerly limit, and that it was more vigorous 

is shown by the relatively great erosion that it accomplished as well as by the greater thickness 

of drift that it laid down, not only on Long Island but over a large section of the country. 

The fact that the beds over which the Montauk ice passed lay beneath the sea and were saturated with water, and hence possibly presented more favorable conditions for folding than the 

incoherent surface gravels over which the Wisconsin ice sheet moved may have had'somethiilg 

to do with the more extensive folding by the older ice sheet. Again, the clay beds, which are 

most susceptible to folding, were more thinly covered in Montauk time than in Wisconsin 

time,· and being thus much more accessible to the ice they consequently suffered greater· disturbance·. Still another factor favorable to greater erosion during the :Montauk was the submergence, which was enough to prevent the accumulation of snow, though not enough to affect 

the erosion materially. The surface was therefore free from the mantle of snow or stagnant 

ice, which was present outside of the glacier in a part at least of Wisconsin time, and over which 

the glacier proper passed with little effect, as indicated by the Smithtown '' driftless" area .. 

FIRST" RECESSION OF MONTAUK ICE. 

The fact that extensive deposition followed the active erosion of the first advance shows 

a decrease in the vigor of the invasion, doubtless due in part to the overloading of the ice by 

debris. There seems, however, to have been a decrease in ice movement, marked first by the 

several minor advances and retreats recorded in the alternating beds of till and gravel in the 

:Montauk region, and finally by a more marked retreat during which the ice front was moved 

back at. least as far as the north side of the Middle Island belt of the Manhasset formation 

(fig. 107, p. 120). It then rested about on a line reaching from the vicinity of Manorville along 

Peconic River, through Riverhead, north of New Suffolk through Cutchogue, northwest of 

Great flog Neck, and along the north side of Shelter Island. The North Fluke proper was 

probably still covered by ice, as ~here is no record in the shape of deposits to indicate that the 

ice retreated beyond its southern border. In western Long Island the ice front lay somewhere 

north of the southern coast. 

During the retreat of the ice there was more or less deposition by -glacial streams, marked 

by the gravels found here and there between the erosion unconformities of the earlier and later 

:Montauk ice invasions, but on the whole the deposition was on a very small scale until the ice 

came to a halt along the line just traced .. On this line the margin probably remained stationary or nearly so fo~ a period during which considerable accumulations of gravel were laid 

down. The greater part of the gravel deposits of Robins Island, Nassau Point, Great Hog 

Neck, and Shelter Island were apparently accumulated at this time, probably as sand and 

gravel deltas at the mouths of glacial streams. From the outline an,d topography of the various 

masses, clue weight being allowed to subsequent wave erosion, it appears that the deposition took 

place not in an open body of water, but rather iri irregular spaces among a number of detached 

residuary ice masses occupying the greater part of the interflu~e area. It is not improbable 

that many small ice masses were buried beneath the gravel accumulations at this time and by 

their subsequent melting gave rise to some of the warpings now observed in the beds as well 

as to many of the numerous kettles. 

As to the altitude of the land at this time very little is known. The heights of the deposits, 

are not accordant and afford no in<;lication of any common factor in the determination of their 

levels. Cuesta-like surfaces such as characterize both the late Manhasset and the Wisconsin 
208 GEOLOGY OF LONG ISLAND. 

outwash deposits are entirely absent, and traces of beaches, if any were ever formed, were 

removed by the later ice advances. The topography in a broad way resembles the kettle or 

broken plains of morainal aspect, such as are not uncommonly associated with subaerial outwash 

deposits laid down over and around ice blocks. 

READVANCE OF THE MONTAUK ICE. 

Evidence of the readvance is afforded by the strong scouring and folding of the beds laid 

down during the recession, which thus lie between two strong unconformities of ice erosion. 

The advance was least in western Long Island, where the· ice appears to have reached little or 

not at all beyond the north coast, and was greatest in the vicinity of the South Fluke, where it 

extended beyond the south shore into the sea. It is to this readvance that the strong folding 

and faulting of the Middle Island Manhasset belt is referred. The advance was vigorous and 

the ice was even more active in erosion than during the e.arlier invasion, both scouring and 

folding occurring on a la.rger scale than at any previous time. 

HEMPSTEAD GLACIAL SUBSTAGE. 

FINAL RETREAT OF THE MONTAUK ICE. 

The activity of the ice sheet on the second invasion seems to have terminated rather 

suddenly, the period of vigorous erosion giving place to one of extended aqueous deposition 

without the usual intervening period of till deposition, except in the Micldle Island belt. To 

this period between the cessation of erosion and the beginning of the ice· retreat is referred 

~. 

the form'i:ttion of the older olitwash deposits (Hempstead), 

~ :J· which here and .there project through the Wisconsin outwash 

~--__, 1 on the south side of the island. ~----~--~------------~ Y4- Mile . After the retreat of the ice from the region of the South 

FIGuRE 20l.-Profile or imperfect 40-foot terrace Fluke no deposits of consequence were laid down until the east of Fort Pond, Montauk, as seen looking from ice reached a line close to the north shore of the island. 

Second House, with higher Manhasset and mo- Here the ice seems to have made a somewhat extended 

rainal hills iB distance. 

halt, and broad sloping outwash plains were laid down 

along its front. Traces of these old plains in the form of kettle valleys and other old 

drainage lines (many of them likewise partly filled with later drift) are found at many points, 

as elsewhere described (p. 174), from Mille:r Place, near Port Jefferson, to Orient Point. 

Although these old gravel plains are everywhere obscured and many are completely buried 

by the later Wisconsin outwash, they appear to possess,· in their upper parts at least, the typical 

fan shape and structure of subaerial deposits. Whether or not the lower parts were below 

sea level can not, owing to the general absence of beach lines or other marine phenomena, be 

determined with certainty, such features, if ever formed, now being hidden by the mantle of 

Wisconsin outwash. The terraces (fig. 201) at the 40-foot level on Montauk, which appear to 

have been formed soon ~fter the completion of the Hempstead deposition, would appear, 

however, to point to a submergence at this time. 

VINEYARD INTERGLACIAL STAGE.· 

EROSION. 

The deposition of the Manhasset formation (including the Herod gravel member, Montauk 

till member, and Hempstead gravel member) was followed by an interval of strong subaerial 

erosion, known as the Vineyard stage, during which the deposits were trenched from an ~levation 

of 200 feet or more above to at least 150 feet below the present sea level, and extensive drainage 

systems with many branches and dendritic headwaters, such as the Nissequogue system near 

Smithtown, were developed. The erosion of this stage was at least 50 and probably 100 times 

,greater than that which has been effected in post-Wisconsin time. In fact the two ate comparable in magnitude to a river valley and a small gully-the post:.. Wisconsin work consisting 

of hardly more than the formation of a few amphitheaters, a slight notching of the cliffs extending back only a fraction of a mile, or an insignificant trenching of the old valleys. It is probable 

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PLEISTOCENE EPOCH. 209 

that the Vineyard stage of erosion· was of much longer duration than the post-Wisconsin, 

althqugh from the f_act that the land is known to have stood considerably higher in the earlier 

period it is difficult to make accurate comparisons. The climatic conditions were probably 

not materially different, and even if they were more favorable to erosion in the earlier than 

- in the later stage, the difference could not, with any reasonable assumption as to rainfall and 

absence of vegetation, have been very great. 'In fact, with porous materials such as the sands 

and gravels of Long Island, the amount of precipitation has relatively little effect on erosion, 

except close to the sea, unless it comes in the heavy downfalls of so-called cloud-bursts. 

In the later part of this period of erosion the land stood at least 150 feet higher than at 

present, as indicated by the depth of the submarine channels off Montauk, and the depth of t.he 

I-Iudson submarine channel suggests that it probably stood considerably higher than that.· On 

Montauk there are evidences of a 40-foot terrace, which if due to erosion would indicate a subnlergence as well as an uplift during the Vineyard interval. In a view looking eastward from the 

hills on the west shore of Fort Pond Bay the terrace stands ou.t distinctly, having the appearance 

shown in figure 201. It has a coating of Wisconsin drift, which would indicate that it was 

fonned in the preceding or earlier. stage of the Pleistocene. · . 

On the New.Jersey coast and farther south there is a persistent marine or terrestrial terrace 

known as the Cape May, formed practically at sea level, and now standing at an altitude of 

40 feet or less, which has generally been regarded as of post-Wisconsin origin. This terrace 

is not developed on the Wisconsin outwash deposits in western Long Island, although on 

Raritan Bay, only 10 miles distant, where the supply of material was no greater and the exposure 

was much less, it has a typical development. These facts strongly suggest that the terrace, 

if formed on Long Island, antedates the Wisconsin outwash and lies buried beneath 'it. It is 

thought, therefore, that there was a rather widespread subsidence in the Long Island region, 

during which the land stood about 40 feet lower than at present. ·The date of this subsidence · 

was probably the early part of the Vineyard interval, before the uplift which brought on the 

stream erosion. 

DEPOSITION. 

O~g to the elevation of the Long Island region in the Vineyard interglacial stage, no 

general m~tle of deposits could be formed over its surface. The conditions were, however, 

not unfavorable to the development of soils over the surface, of peat and marsh deposits along 

the streams, and of fossiliferous beach deposits upon its borders. Such accumulations were, 

indeed, formed at many points and ~ay still be recognized when penetrated by wells. The 

maximum elevation, as shown by the submarine Hudson valley, appears to have been at least 

700 feet (seep. 63); but erosion had not attained any such depth on Long Island, most of the 

deposits of the Vineyard stage lying less than 100 feet. below sea level. They would therefore appear to Jllark the closing stages of the interval, when the subsidence had progressed nearly 

to the present point. 

WISCONSIN GLACIAL STAGE. 

FIRST ADVANCE OF THE ICE. 

The only evidence as to the nature of the climate during the long period of Vineyard erosion 

is that afforded by the shells obtained from wells. These seem to indicate that it was no colder 

than during the Gardiners deposition, when, as has been seen (p. 198), the climate was not far 

different from the present climate of northern New. England. Toward the close of· the stage, 

however, the climate became colder, or at least more favorable for the collectio,n, and rete)ltion 

of snow, and the region eventually became covered with ice. 

Whether the ice invaded the region as an advancing glacier, like those pushing their way 

down the valleys in the Alps, or whether the region was first covered with snow which later 

thickened and changed to ice is· not positively known. There are several indications pointing 

to the latter alternative. For instance, it seems impossible to account for the complete preservation of the drainage system west ()f Smithtown on the hypothesis of an advancing glacier 

plowing its way over the loose gravels, but the absence of erosion is easily accounted for if it is 

assumed that the vaneys were previously filled with snow or snow ice; over which the ice moved 0 ' 
210 GEOLOGY OF LONG ISLAND • 

. :without coming into direct contact with the surface itself. Again, the absence of till outside 

of the moraine in the Bridgehampton region is better accounted for on the theory that the masses 

giving. rise to the kettles of the outwash plain at this point represented ·extramorainal accumulations of snow rather than residual ice blocks from a true glacial advance. 

The climate along the borders of the glacie1 during the maximum known advance of the ice, 

when its front rested along the ·line of the Ronkonkoma moraine, was probabiy very severe, at 

least in regard to the amount of precipitation as snow, being in all probability even more 

rigorous than in the region of the semicontinental ice sheet of Greenland at the present time. 

In the Greenland region the scattered valley glaciers are able to take care of the excess of accumu-

. lation of the centrall.ce cap, whereas in 

____ ... ,,,/,--- -,,,,____ -------,,________ the Wisconsin stage on the continent a 

-----~----2.--------------; -------- continuous front of thousands of miles 

::~;~~~~~~~~;~-~~ ~~~~~ifZH~~~~~;~~~~~~~-=-:- ::~ecoosaxy to accomplish the same 

----------------.----.,..----------------------------· Stratified glacial deposits are found 

0 5 Feet up to an elevation of 410 feet; hence the 

·FIGURE 202.-Section at top of bluffs between Woodhull and Rocky Point landings, 

.. showing folding produced by the Wisconsin ice sheet. The figure illustrates thE> 

breaking up of the folds where in contact with the ice at the top and their disa:Jr 

ice must have risen to at leas't that height 

above the sea level. In a living glacier 

the ice in the immediate vicinity of its 

front is commonly at least twice as high •· pearance at lower levels. · 

as the moraine. If this· relation held in Long Island, the ice may have reached a height of 1,000 

feet alongthe'margin. Notwithstanding its considerable thickness, which could hardly be assumed 

·as less than 500 feet, the Wisconsin ice sheet was not vigorous. in its erosion, indicating either 

,an overloaded condition or a very slow movement. Inasmuch as there is no evidence of any 

considerable amount of englacial material, it is probable .that the sluggishness of movement 

~accounts for the insignificance of its erosion and explains the relative scarcity of Wisconsin tilL 

The deficiency of vigor compared to that of the Montauk ice is well brought out by the 

smaller scale of the folding. In m·any places -the Wisconsin ice overrode the Manhasset f?rma-

~Covered with ice at the Ha'rbor Hill stage 

74~ 

FIGURE 203.-Sketch map showing relative positions of ice during the Ronkonkoma and Harbor Hill substages of the Wisconsin stage. 

tion without producing the slightest recognizable disturbance; elsewhere the folding was limited 

to a disturbance of the beds within a foot or two of the surface (fig. 202). Here and there, how-

. ever, the disturbance was somewhat more extensive, reaching some distance below the surface, 

as shown in Plate XIX, A (p. 114). Nowher~ were such profound folds observed as the larger of 

those produced by the older invasion, although there are indications that in many places where 

bluffs and other steep slopes opposed the ice movement the folding was considerable. 

There was, however, U!Ore or less material, both beneath and within the glacier, that was 

either set free directly from the ice upon its melting or indirectly:.::deposited by minor rivulets 

issuing from the margin and . building up the great Ro_nkonkoma moraine (fig. 203) and 

• 

• 
.• 

PLEISTOCENE EPOCH. 211: 

the more or. less detached gravel fans, which became joined into the nearly continuous plain or" 

outwash from ice along. the Ronkonkoma moraine. The sandy or pebbly loam present locally 

on the outwash presumably represents a "finishing deposit" laid down in the closing stages of 

deposition. Definite channels, representing the lines of outflow of the water just before. the 

supply was cut off by the final retreat of the ice, lead from the moraine to the shore. 

Estimates as to the duration of the ice invasion can not be made witp. accuracy in the 

absence of any definite criteria upon which to base calculations. According to F. J. H. Merrill, 

however, bowlders from as remote a source as the Adirondacks have been recognized in the 

moraines; and a journey of 200 miles is not improbable for many of the erraties. The rate of 

movement of a continental glacier is not known, but it must be many times slower than that of 

glaciers of the Alpine type, for these are fed by collecting areas several times as large as the 

distributing glaciers; whereas in continental ice sheets the oppos~te is true, the area of the 

sheet subjected to melting being larger than the area of collection. Probabl.y the movement 

was not more thm1 a few feet a year. Even at the rate of 100 feet a year, which is more than 

many valley glaciers average, it woulcl"take over 10,000 years to bring a single bowlder. from the 

Adirondacks to Long Island.·. It is· not unlikely that the duration even· of the Ronkonkoma 

substage was several times as great. · . · 

FIRST RECESSION OF THE ICE. 

The upbuilding of the Ronkonkoma moraine and the related outwash plain continued as 

long as the ice front remained stationary; or, in other words, as long as the melting of the ice 

margin was just counterbalanced by the advance of the glacier. This period w.as succeeded by 

one of the greater general warmth or lessened precipitation, which caused a retreat of the ice 

front from its position along the moraine throughout the region east of Lake Success, sout~ 

of :Manhasset Bay. The retreat began at the east end of the island and was taken up progres:; 

sively westward. West of Lake· Success the morainal deposits of the succeeding substage li~ 

south of those of the Ronkonkoma substage, and it is doubtful if any retreat of the ice occurred 

in this region. If there was any it was more than counterbalanced by the later advance. It is 

likewise unknown whether in the region east of Lake Success the ice retreated any considerable 

distance to the north and then readvanced to the line of the moraine, or. whether it halted on. 

reaching the line now marked by the I-Iarbor Hill moraine. The presence of kettles in the 

subsequent outwash from ice along the I-Iarbor I-Iill moraine indicates, however, t~at· the 

upbuilding of the late moraine followed very quickly after the recession of the ice and before the 

residual blocks had had time to melt. The retreat does not appea:c to have been uniform a~d 

continuous, but was rather marked by t-emporary halts, during which accumulations of consid~ 

erable importance were laid down in the intermorainic area. ·· 

READVANCE OF THE GLACIER. 

After the influence causing recession became exhausted the ice took on new activity, 

advancing with a regular front to the line now marked by the Harbor Hill moraine (fig. 203), 

and bringing on a new period of moraine and outwash accumulation. The conditions prevailing, 

however, differed somewhat from· those of the earlier stage. A larger proportion of till was 

brought to the moraine, but the supply of sand and gravel, as indicated both by the smaller 

extent of the outwash deposits and by the smaller quantity of material in the moraine, was 

considerably less. In fact, the pronounced channels leading southward from the moraine of this 

stage show that the glacial waters, instead of being overloaded with gravel and sand, often possessed relatively little such material, and their work at such times became erosion rather than 

deposition. vVhat deposition there was followed very quickly upon the retreat, for the numerous 

kettles of the outwash plains indicate the existence of residual ice blocks at -many points. 

As to the duration of the second stage of activity little definite evidence is at hand. -The 

large quantity of till and bowlders suggests a prolonged ice movement, but the small quantity of 

outwash suggests the reverse. There is no basis for concluding that it differed greatly in length 

from the first advance. 
212 G:ElOLOGY OF LONG ISLAND. 

FINAL RETREAT OF THE ICE. 

The final retreat of the ice seems to h~ve been rather abrupt and to have taken place 

.without notable halt in the Long Island region, as is testified by the general ab~ence of retreatal 

deposits. It is probable that as the climatic conditions ameliorated, the activity of the ice 

movement gradually lessened and finally ceased, and the margin of the ice sheet became broken 

llp :into detached masses as the ice melted. The masses occupying the valleys ·doubtless persisted longest, especially. where covered with retreatal outwash and other debris. Under such 

- conditions buried n1asses may have lingered for hundreds of years, possibly even after the 

region had .become clothed with forests, as at the Malaspina Glacier in Alaska to-day. The 

porosity of the deposits and the free circulation of the ground waters would tend, however, 

to hasten the melting of such blocks. 

In the earlier stages of the recession numerous, lakelets probably existed between the ice 

front and the highlands of the north side of the island, but :in general they seem to have been of 

short duration. No beach lines and only very small deposits have been· recognized, the Port 

W ash:ington delta and the outwash on Lloyd Neck being the only marked ."exceptions. 

RECENT EPOCH. 

WORK OF WIND AND WATER. 

The final retreat of the Wisconsin ice sheet left the island standing a few feet higher than 

at the present time and probably nearly or quite destitute of vegetation, so that wind, streams, 

and waves were free to begin their work of reshaping the island. The work of the wind did not 

continue long, for except in the region south of Port· Jefferson and along the coasts there. is 

little evidence of dune formation, notwithstanding the favorable· character of the materials, 

and none whatever of pebble faceting such as is found in parts of the Manhasset formation. 

It is probable that the small amount of wind work over the island as a whole is due to the fact. 

that vegetation almost immediately covered the surface. Dunes have, however,· continued to 

form on the coast to the present day, constituting high belts all along the south shore and 

capping the bluffs of the north shore at many points east of Port Jefferson. 

Upon the retreat of the ice, waves a~d. ocean currents began to sculpture the shore and to 

form numerous spits, bars, and connecting beaches. The result has been a straightening of the 

coast line by the formation of the great barrier beach on the south side and the 'truncation 

of the projections of the north shore. In fact, where the highlands come to the shore there is 

scarcely a point that is not marked by sea cliffs, most of them free from vegetation and not a 

few still undergoing active erosion. · 

Details of the work of the various agencies acting in post-Wisconsin times are given in the 

discussion of Recent deposits (p. 176). 

SUBSIDENCE OF THE LAND. 

EVIDENCE. 

Submerged tre~ stumps and beds of peat on Long Islan·d have been described by many 

writers. W. W. Mather/ in 1843, reported stumps and logs beneath the water near Peacock 

Point, between Oyster Bay and Hempstead Harbor. In 1857 George H. Cook 2 ·mentioned 

buried timber in the towns of Hempstead, Babylon, and Islip. At Hempstead an island 

covered with trees within the memory of Cook's informant was a salt marsh at the time he wrote, 

the highest part of the former island being lower than the meadow then existing. Elias 

Lewis, jr.,3 in 1869 recorded a series of observations indicating that large areas which formerly 

had been swamp al).d woodland were then below the water level. Remains of fresh-water 

1 Geology of New York, pt. 1, 1843, p. 21. 

2 On a subsidence of the land on the seacoast of New Jersey and Long Island: Am. Jour. Sci., 2d ser., vol 24, 1857, pp. 341-355. 

a Evidences of coast depression ~long the shores of Long Island: Am. Naturalist, vol. 2, 1869, pp. 334-336. 

• 

• 
RECENT EPOCH. 213 

vegetation were abundant 4 to 91 feet below the s,urfaces of the ma~hes ,on the south side of the 

island (then about at .sea level). Lewis described roots in place 10 feet below sea level. Near 

Fort Hamilton the tide overflowed marshes with trees still standing, and stumps were seen far 

out. It is said that 100 years earlier stumps abounded in Great South Bay, especially east of 

Islip. A line of fence posts put in a hundred years. before were found in place beneath the 

sand at extremely low tide. Submerged meadows were seen at several places on the north 

shore, one a few miles east of Port Jefferson extending half a mile from the shore and to a depth 

of 16 feet in a compact mass. In a later paper 1 Lewis presents a number of additional observations. ·At Islip many stumps, the remainder of a forest still growing on the shore, were standing 

on meadows of William Nicol. The absence of kitchen middens is accounted for by the relatively recent submergence of the former marshes of Great South Bay. A large number of submerged pine stumps were seen in ~ bay a few miles east of Islip; Many stumps stood about 

the head of Great Peconic Bay and off the marsh north of the lighthouse at Montauk ·Point. 

Lewis also mentions many instances of lignite being brought up in wells, but these beds are now 

known to be pre-Wisconsin and hence do not bear on the question of recent subsidence. More 

recently Veatch has reported marsh muck to a depth of 23 feet at Fort Lafayette, peat at 25 

feet at the. Brooklyn Navy Yard, and tree trunks from the surface to a depth of 9 feet near 

Patchogue. 

In addition to the evidence mentioned in the foregoing p'aragniphs most of. the earlier 

writers cited the occurrence of oyster and other shells at considerable de.pths in .wells. It is 

now known, however, that most if not all of these were from the Gardiners clay, the ·Jacob sand, 

or the Vineyard formation, and not being of postglacial origin they afford no evidence- of recent 

·subsidence. The same is true of the wood reported at considerable depths, this being found in 

the Vineyard formation, the Gardiners clay, and the Cret~ceous beds, as well as in the R~cent 

deposits. 

Phenomena of the nature cited have been generally accepted as evidence of recent subsidence, but recently there has been a tendency on the part of some geologists to question such 

an interpretation. A number of occurrences noted in connection with the present field work 

threw doubt on certain of the supposed evidences and emphasized the necessity of caution in 

using submerged vegetable accumulations as criteria of subsidence. 

Thus, in the vicinity of Luce Lancling, north of .Riverhead, the peat, with its included tree 

stumps, appears to have been largely let down to its present position on the beach below hightide level by undermining. Near Prospect Point, north of Port Washington, the process of 

undermining could be seen in actual operation, the layers of peat projecting through the sand 

·being bent and cracked as they are let down (Pl. XXVI, A., p. 182), although sufficiently connected to form a more or less continuous sheet at a level below their original position. In 

both-places the beds have been exposed by the encroachment of the s·ea on marsh and swa1np 

deposits behind barrier beaches. ' 

In addition to the evidences cited there are impor.tant botanical indications of subsi.dence 

in comparatively recent time. These are afforded by the ranges of the common salt-marsh 

plants, which, according to C. A. Davis, are as follows: 

Range of common salt-marsh plants. 

Species. · Range. Time covered by sea. 

Juncus gerardi Loisal (bl~ck grass)......................................... Between level of ordinary tide and Covered by spring tides about 

upper limit of spring tides. twice a month. 

"Spartina patens association" (salt-marsh grass): Spartina patens (Ail.) Extends 9 to 12 inches above and below Covered about 1 hour each 

Muhl. and Distichlis spicata (L.) Greene. mean high tide. tide. 

Spartina glabra Muhl. (salt thatch). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Between mean high tide and half tide, Covered about half of time. or mean sea level. 

Zostera marina L. (eel grass) ................ ,.............................. Below low-tide limit.................. Permanently covered. 

I Ups and downs of the Long Island coast: Pop. Sci. Monthly, vol. 10, 1877, pp. 434-44G. 
214 GEOLOGY OF LONG ISLAND. 

.. Mr. Davis, who made a special study of the peats of the island fo:cthe Geological Survey 

in· 1911, making a large number of borings and taking samples at short intervals from the 

surface to a depth of 10 feet, is also the authority for most of the following descriptions. 

At the salt marsh west of the head of Mount Sinai Harbor, about 1~ miles ·northeast of 

Port Jefferson, borings showed the "Spartina patens association," which is characteristic of 

the zone at high-tide level, to extend from the present surface to the underlying gravel at a 

depth of 5 feet, apparently indicating long-continued subsidence, with an upbuilding of peat 

at a corresponding rate. 

A 9-foot test hole in a salt marsh 1! miles east of Riverhead showed a semifluid fresh-water 

peat for the entire depth below the thin surface mat of salt-water plants, indicating that the 

marsh has been covered by the tides only at a very recent date .. 

At the Mill Creek marsh, 5 miles east of Riverhead, the boggy wooded swamps above 

tide level give plaee downstream to a brush-covered area containing tree remains, followed by 

an open fresh marsh with scattered stump's and shrubs, and this in turn by a marsh with the· 

"Spartina patens association," overlying nearly 9 feet of fresh-water peat with aht~ndant stu:p1ps 

and roots, principally about 5 feet below the surface The incursion of the sea, as at the locality 

described above, is evidently very recent. ·The salt marsh along the east tributary of the main 

creek contains many stumps' and logs at and below the surface and was clearly a forested 

swamp, also only recently invaded by the sea. 

At the end of Pine Point, east of the marsh last described, pine roots show in the beach to 

or below low-tide level. A cliff about 2! feet high, cut in the peat by the waves on the west 

side of the point, showed a gradation from a blackened sand soil at the base to Spartinq- patens 

turl at the top. · 

Another marsh a few miles east of Riverhead showed 8 feet of Spartina patens peat overlying 

a foot or more of brackish-water peat. Near the boat landing east of Meeting House Creek, 

2! miles east of Riverhead, 3ffeet of Spartina ·patens peat was found above a blackened sandy 

gravel soil bed. 

Swan River Marsh, near East Patchogue, has the appearance of occupying a drowned 

valley. ·Toward the sea a wooded swamp gives way first to shrubs, next to fresh marsh, then 

to brackish marsh, and :finally to salt· marsh of the "Spartina patens association." Partly or 

completely buried stumps abound below the salt turf,.here about a foot thick. . -!\n essentially 

simiiar sequence was- noted along Mud Creek in the same locality. , 

The conditions along the-north shore are less favora:ble for study, but examples of submerged 

peats and of progressive subsidence doubtless occur atfa_ number of points. Near Lloyd Point, 

on Lloyd Neck, Huntington, the following succession was noted by the present writer at a point 

where the marsh laps up on the gently sloping surface of the upland: (1) Brush-covered upland; 

(2) marginal upland zone where bushes that had been recently killed by salt water reaching 

the roots through th~ porous sands still remained practically intact, even to the smaller twigs; 

(3) border of marsh with nearly intact bushes projecting 'through several inches of peat.; (4) 

belt located a few feet outward from edge of marsh with only trunks of shrubs remaining; (5) a 

zone several rods from the edge with only low stumps visible; and (6') an outer area showing 

only the salt-marsh turf. 

The occlirrences noted appear to be too widely distributed and too variable in surroundings 

to admit of explanation by any other than a single general cause, seemingly a slow, long-con-

_tinued, and apparently fairly unifor~ subsidence of the land with reference to sea level. 

All authorities are probably agreed that such a subsidence has occurred in comparatively 

recent time, but there is a radical difference of opinion as to whether the sinking has continued 

down to the present day and is now going on. 

The peat sections, as developed by borings made by Mr. Davis, show no variation in character that would indicate a halt in accumulation at the present time, and his observations on 

the rate of accumulation of Spartina patens peat near Lynn, Mass., based on cinders incorporated 

in the material since the building of the railroad more than 50 years ago (6 to 8 inches in a century), would seem to indicate. that if there had been any halt in a movement of corresponding 

-. 

. . 

.. 
. ' 

RECENT EPOCH. 215 

rapidity the upper limit of salt-marsh growth would soon be reached and it .would be replaced 

by fresh-water turf. This is 1nariifestly not the case. 

On the other hand, it has been urged by D. W. Johnson that the belts of beach ridges of 

essentially the same height, formed progressively one after another at a number of points along 

the Atlantic shores, are evidences of present stability of the coast line. Johnson also considers 

that dead trees in conspicuous numbers, which he believes would inevitably be of general distribution under the hypothesis of present subsidence, are really of local occurrence and are 

rarely found except where a breach has been made through some protecting barrier, or where 

'physiographic factors have produced changes in tidal levels. 

CON.CL USIONS . 

. ·The fact seems to be established that a subsidence of many feet has taken place since the 

retr~at of the latest or Wisconsin ice sheet, and that ~alt water now invades scores of marshes 

in which trees grew so recently that the stumps still project above the surface. 

It is perfectly plausible to attribute, as Johnson has done, the invasion in individual places 

to variations in size, shape, or location of the openings through which the ti4al waters obtain 

access to the marshes,· or to changes in the character or position of the beach ridges or other 

protecting barriers themselves. Such changes would be expected, however, to favor the 

exclusion of salt water quite as frequently as they would its admission, and fresh-water peat 

should be found overlying salt-water peat as commonly as salt-water peat overlying freshwater ,peat. Although the former succession may exist, the thousands of borings made by Mr. 

Davis show, except where the sea has been shut off by dikes or otherwise excluded, a practically 

entire absence of such succession, the nearly universal order being salt-water forms above 

fresh-water forms. According to Mr. Davis, in some of the places where there has been a recent 

incursion of salt water, as in certain of the inlets near Portsmouth, N.H., there are ri.o evidences 

of either present or past barriers that could have influenced tidal levels. The writer also has 

noted a number of localities where there seems to be no probability of former barriers. 

The apparent change~ in the level of bench marks at several points along the coast appear 

to be inconclusive, as radical changes in tidal levels are likely to result from artificial causes, 

such as the building of docks or the dredging of channels, but the fact that these changes always 

point in the same direction, namely toward subsidence, seems to indicate that they should be 

given considerable weight .. 

Although there are no broad or extended belts of dead trees, except where changes· of tidal 

levels of considerable 1nagnitude have occurred suddenly through the breaking of barriers or 

changes in inlets, :Mr. Davis states that dead trees are not only generally distributed along the 

whole coast but are fully as numerous as the conditions of subsidence would suggest. 

The action of salt water upon vegetation is in a high degree selective, and while prolonged 

or repeated submergence would produce a general belt of dead vegetation, the incursion of 

single high tides, which, especially during periods of subsidence, always advance well beyond the 

norn1al tidal limits, would kill only the weaker species. More resistant species would survive 

but might appear sickly or partly dead. Still others might survive for many years. As miks 

and other hard-wood stumps last an average of only 15 or 20 years, they may entirely disappear, 

while trees or shrubs not vitally injured by the tides that killed the oaks are still living. 

This transitional or sickly belt is not conspicuous, but may usually be recognized without 

difficulty by careful observers., From what the writer has seen he believes the condition to be 

general in New England and on Long Island. It points strongly toward a present downward 

movement of the crust. It can hardly be otherwise if the limitations of the vertical range of 

salt-marsh flora are as stated by Mr. Davis. 

The chief evidence against present subsidence is that afforded by the parallel.beach ridges 

described by D. W. Johnson. At Cape.Canaveral, Florida·, for example, there is a broad belt, 

half a mile or more in width, of low parallel sand ridges having the appearance of beaches formed 

one after another and all of essentially the same height. These ridges are certainly very suggestive of stability of elevation with reference to sea level. -Farther north, although sirnilar . 
216 GEOLOGY OF LONG ISLAND. 

ridges exist, the width ·of the belts and the number of ridges is less .and their evidence is more 

open to question. It seems to the writer that so many factors of uncertain value enter into the 

computation of the time required to form such beaches as that at N antasket, Mass., even on the 

assumption that there has been no material change of level during the period of their formation, 

as to outweigh the m~ss of evidence favoring continued subsidence. 

On the whole, the view that the subsidence has continued down to the present time and is 

now going on is regarded by the present writer as· the most probable. The rate suggested by 

Mr. Davis is perhaps higher than would be expected, but recent additional unpublished d_ata 

collected by hiin seem to bear out the assumption of a rapid crustal movement. 

The subsidence in the Long Island region since the retreat of the Wisconsin .ice sheet is 

apparently not more than 25 feet, which at an average rate of 6 inches a century would require 

a period of 5,000 years. That the movement has been much more gradual in the past is possible, but the uniformity of material to the depth reached by borings (10 feet) seems to indicate 

that it has been uninterrupted for a considerable period of time. Earlier interruptions or 

reversed movements are entirely possible, but the e~dences of them, if any exist, are presumably now some distance below sea level. 

LENGTHS OF PLEISTOCENE AND RECENT STAGES AND SUBSTAGES. 

The lengths of the several Pleistocene stages. and substages are very difficult to determine 

because of the lack of knowledge of the many local conditions that always enter into problems 

of erosion and deposition. This difficulty is greatest in comparing stages-of accumulations with 

those of degradation. It is possible, however, to recpgnize a progressive change in length from 

the earlier to the ~ater stages, estimates of which· are given in the following table, in which the 

unit A is taken as the length of the Recent epoch and Bas the length of the Wisconsin stage of 

glaciation. The estimates are, of course, only approximate, especially as to the length of the 

stages or substages compared with the time units, but in general the relations are probably not 

far wrong. For example, it is almost certain that the Vineyard erosion interval was at least 

. five times as long as the Recent epoch, that the period represented by the Gardiners and 

Jacob stages, as indicated by erosion in New Jersey, was even longer than that of the Vineyard 

degradation, and that the _post-Mannetto stage was to all appearances longer than all subsequent Pleistocene time. The comparisons of the glacial stages are less reliable, but it is certain 

that there has been a variation similar to that indicated in the table. 

.... 

.• 
., 

.• 

SUMMARY OF OROGENIC MOVEMENTS. 217 

Relati·ve lengths of Pleistocene stages and substages on Long Island. 

Estimated 

length as 

Epoch. Stage. Substage. Nature. Chief work. Remarks. compared 

to Recent 

or to Wisconsin. 

Recent. Postglacial. Insignificant erosion and depo- sition. A. 

Degosition of 5 to 20 feet of till, Short period as compared to Wisconsin. Glacial. t · ~ck outwash, and high mo- preceding glacial stage. B. rarne. 

Vineyard. Interglacial. Extensive erosion of older drift. Erosion many times greater than Recent time. ·5XA. 

Hempstead. Glacial. Accumulation of 25 to 100 feet of 

gravel. 

Manhasset. Montauk. Glacial. Accumulation of 50 feet of till. 

Thickness of deposits points to great length as com- pared to tho Wisconsin 5XB. 

stage . .. 

Herod .. Glacial. Accumulation of 100 feet or more of gravel. 

Pleistocene. Jacob. Transitional. Accumulation of 25 feet of clayey Thickness of clay imd ex- sand. tensive erosion in New 

Jersey show that these lOX A. stages represent an exceedOard'iners. Interglacial. Accumulation of 50 to 100 feet of ingly long interval. 

clay. 

Exposures ofcoutemporane- ous deposits in New Jersoy (Pensauken formaJameco. . Glacial. Accumulation of Jameco gravel. tion) show this to have lOX B. 

been the most important I period of deposition next to the Mannetto stage. 

Post-Mannetto. In terglacia I. Reduction and nearly complete Longest interglacial stage. 20XA. removal of Mannetto gravel. 

Mannetto. Glacial. Accumulation of 600. feet of Longest glacial stage. 20XB. gravel. 

SUMMARY OF PLEISTOCENE AND RECENT OROGENIC MOVEMENTS. 

In the eadier stages of the present investigation it was assumed tha·t the principal Pleistocene 

deposits were of the nature of coastal-plain formation and that their upper surfaces indicated 

approximately the position of the sea level at the time of their formation. On these assumptions 

a depression of 300 feet was postulated as taking place during the deposition of the Mannetto 

gravel and 200 to 250 feet by the completion of the Manhasset accumulation. Further study, 

however, has shown that the Manhasset and, to a lesser extent, the Mannetto exhibit many 

featuTes analogous to those of the Wisconsin outwash plains developed.on the south side of the 

island, and it is now thought that they are· in large measure of similar origin. It has been 

necessary, therefore, to turn to the adjacent coast of New Jersey for evidence as to submergence. 

SimtJarly it was ascertained in the course of the investigation that the .data afforded by the 

erosion valleys were insufficient to determine the a1nount of uplift, and re.course to the s·Ibmarine IIudson Valley was necessary. The movements are shown graphically in figure 204 

(p. 218). . 

Mannetto depression.-As pointed out above, it is not improbable that· the Mannetto gravel 

of Long Island is in part of the nature of an outwash plain and was form_ed above sea level. 

For this reason it is impossible t6 determine its position with reference to sea level from the 

elevation of its remnants on the island. The Bridgeton formation, however, which seems to be 

the New Jersey representative of the Mannetto, was not· developed in the vicinity of the ice 

sheet but rather as a coastal-plain formation. Considerable areas of it face the open sea, and 

whether due to the action of the waves or to drainage at low gradient, their development could 
218 GEOLOGY OF LONG ISLAND. 

have taken place only near sea level. In· no other way (in the absence of barriers) could the 

slack drainage necessary for. the development of the flat terraces, under the hypothesis of deposition by streams of low gradient, be maintained. The present elevation of the Bridgeton 

formation on the New Jersey coast ranges from about 100 feet in the southern part. to 200 feet 

in the central part, and indicates a submergence increasing from about 100 feet in southern 

New Jersey to 200 feet or more farther·north. A continuation with the same grade would give 

a depression of 200 to 250 feet in the Long Island region at the time of the Mannetto deposition. 

Figure 204 gives 200 feet, the greatest depression actually known. 

Post-Mannetto uplift.-As brought out in the discussion of the submarine fiudson channels, the deposition of the Mannetto gravel was followed by a long period of erosion, during 

which the rockgorge of the Hudson was probably cut to a depth of 700 feet. After the excavation of this gorge and its seaward prolongation, which probably occupied by far the greater 

part of the jwst-Mannetto interglacial stage, there was, if the submarine cany<;>n is to be referred 

to stream erosion, an uplift of the land far surpassing in magnitude any known Pleistocene 

_movement in the region before or since·. -The· surface, to j~dge from the depth of the canyon, 

______________ I , -150 -200 

-~ 

1 

s 

.... 

iil 

1: 

~ 

~ 

l 

'g 

J3 

1 

gi 

;g 

-~ 

Manhasset 

t . ~ ~- g "' ~ ... ~ 

] --~- - ~ ~ ~ .. ---------------, +50 +20 i +350 : ;--------""---------~ I : 

FIGURE 204.-Position of land with reference to present sea level in the Pleistocene stageS and substages .. Figures indicate feet. 

must have stood 4,800 feet or more higher than at present. Although there is considerable 

doubt that an uplift of this magnitude really took place, its occurrence is tentatively accepted 

as best explaining the character and form of the canyon as described on page 61. 

Jameco depression.-The Jameco gravel probably does not lie at the surface anywhere on 

Long Island, hence evidences of its origin that might be afforded by its structure are lacking. 

Moreover, as it is a glacial or glaciofl.uviatile formation, its position below sea level is of no 

significance. The only evidence, therefore; as to the elevation of the land in Jameco time is 

that afforded by its probable .New Jersey equivalent, the Pensauken formation. The great 

body of the Pensauken formation was deposited in a trough, 10 to 15 miles ~ide, crossing the 

State from the vicinity of Raritan Bay to Trenton and thence extending down Delaware River. 

·This accumulation seems to have been the result of deposition by streams of low gradient in a 

·1nore or less closed basin, hence its elevation of 150 f.eet between Trenton and Raritan Bay is 

_not necessarily an indication of submergence to that depth. Pensauken remll.ants are, however, 

found at similar elevations on the open coast; ·as northeast of Manchester and northwest of 

Asbury Park, hence there is every reason to believe that there was actually a submergence to 

a depth of about 150 feet. The fact th~t the submergence increased from 90 feet in south 

New Jersey to 150 feet in north New Jersey suggests that it may have been somewhat greater 

·than 150 feet on Long Island. 

•. 

.. 
CORRELATIONS OF THE LONG ISLAND PLEISTOCENE FORMATIONS. 219 

· Gardiners uplift.-The 1narsh deposits found at several horizons in the Gardiners clay 

show that this formation at times reached sea level, indicating. an uplift of at least 200 feet 

after the Jameco deposition, as the _contemporaneous Pensauken formation of New Jersey is 

now 150 feet above sea level, whereas the Gardiners clay is commonly 50 feet or more below 

sea level. . 

Jacob depression.-The .Jacob sand is free from marsh deposits, but carries an extensive 

shallow-water fauna, indicating a depth of water not 1nuch greater than during the Gardiners 

deposition. It is probable that the depression was not more than 25 feet. 

Herod (Lnd Montauk depression.-The subsidence, which during the Gardiners and Jacob 

stages about kept pace with accumulation, seems to· have continued through the Herod substage of the Manhasset, so that on the advance of the Montauk ice the water stood 75 to 100 feet 

above the present sea level, as shown by the character of the Montauk till member (p. 200). 

The depression did not, however, keep pace with accumulation at all.times, as is shown by the. 

wind-faceted pebbles in parts of the Manhasset formation. 

Hempstead uplijt.-After the deposition of the Montauk till member of the Manhasset 

fonnation there semns to have been an uplift of 100 feet or more, as the later Hempstead gravel 

n1ember of the Manhasset has the form of a normal outwash plain with contemporaneous 

drainage channels cut to the present sea level or below. A possible halt at about halfway up 

is suggested by the 40-foot terraces on. the :Montauk peninsula. 

Vineyard uplijt.-The valleys in the Manhasset formation were cut to a depth somewhat 

below the present sea level, hence a considerable uplift must have followed the previous period 

of deposition, but ·because of the modifications by the Wisconsin ice sheet and of more or less 

Wisconsin deposition it is impossible to determine with any degree of accuracy the actual 

amount of uplift, and it is necessary to turn again to the submarine valley of the Hudson for 

a definite measurement. As shown elsewhere (p. 64), the upper channel appears to have been 

cut in post-Manhasset time, and as it reaches a depth of 350 feet at its outer edge, an uplift of 

this mnount seems to be established. · 

Wisconsin depression.-There appears to have been in Wisconsin time a depression which 

brought the land to a level about 20· feet lower than at present, as shown in New Jersey by the 

lower marine or low-gradient stream terrace of the.Cape May formation, as developed along the 

New Jersey coast from Cape May to Raritan Bay. This depression is not ~·ecorded on Long 

Island, hence it is thought to antedate the completion of the outwash deposits. 

Recent movements.-After the disapl)earance of the Wisconsin ice the land seems to have 

stood ~omewhat higher than at present, as indicated by the buried and submerged peats along 

the coast, the d,ifference in level being perhaps 25 feet. This would indicate the elevation of 

45 feet in late Wisconsin or post-Wisconsin time. In recent years there has been depression 

estimated at the rate of 6 inches to 2 feet in 100 years. A sinking of not 1nore than 25 feet 

npparently has occurred since the beginning of this move~ent. · 

CORRELATIONS OF THE LONG ISLAND PLEISTOCENE FORMATIONS. 

PROBABLE EXTENSION OF THE FORMATIONS ALONG THE NEW ENGLAND .. COAST. 

MANNETTO GRAVEL. 

The Mannetto gravel, which on Long Island is the oldest of the J;>leistocene deposits, was 

originally the thickest glacial deposit on the island, but its deposition was followed· by an 

erosion stage of such length that the formation was reduced in western Long Island to a few 

remnants, and in the eastern part it was nearly or entirely swept away. This formation, owing 

to either its slighter development or the greater erosion, was likewise largely re1noved from 

the coastal region of New England, if it existed there, so that the Cretaceous, where seen, is 

almost invariably overlain directly by deposits correlated with the J ameco gravel rather than 

by those of Mannetto age. This is notably true of the Cretaceous beds of Block Island and 

Marthas Vineyard, but in an exposure near Scituate, Mass., remnants of gravels which. closely 
2·20 GEOLOGY OF LONG ISLAND. 

resemble the Mannetto have been seen, strongly suggesting that the formation originally 

extended at least to this point. Beyond this locality, however,the ice seems to have reached 

the coast, and the Mannetto materials, if· any were deposited, were probably laid down in the 

region now covered by the sea. 

JAMECO GRAVEL. 

The Jameco gravel seems to be much mor.e persistent in its present occurrence than the 

Mannetto. A gravel at the same horizon as the Jameco is, in fact, well developed beneath Cape 

Cod to Highland Light, Truro, and possibly locally along the west shore of Cape Cod Bay to 

the vicinity of Plymouth, its absence farther north being due to actual occupation of the region 

by ice. On Block Island the Jameco gravel appears to be represented by sands and fine gravels 

with granitic pebbles, having an aggregate thickness of 30 feet or more, occurring between the 

Cretaceous and the clay which is correlated with the Gardiners clay near Clay Head and Balls 

Point and beneath the dark-gray to black clay correlated with the Gardiners at several points 

west of Southeast Light. On Marthas Vineyard similar gravels having a thickness of at ieast 

50 feet are seen beneath the great bed of dark-colored clay correlated with the Gardiners clay 

at the N ashaquitsa Cliffs. On Cape Cod similar gravels occur near Highland Light, with a 

thickness of 30 to 50 feet, below clays which occupy the position and· are of the type of the 

Gardiners clay. On the main coast similar gravels ar~ seen beneath clay at Indian Head, 8 

miles southeast ·of Plymouth. 

GARDINERS CLAY. 

The Gardiners clay likewise appears to be a very persistent formation, a clay of the normal 

Gardiners type and position being found at short intervals all the way from New York Bay 

to Boston Harbor. Besides the development of the Gardiners clay on Long and Fishers islands, 

as described in this paper, a similar clay is found on Block Island, notably in the vicinity of 

Clay Head and Balls Point, near Black Rock Point, and locally west of Southeast Light. On 

the Rhode Island coast. a clay of this type and horizon is seen in places between Watch IIill 

and Point Judith. A similar clay appears on the Elizab~th Islands of Massachusetts; on Marthas 

Vineyard it is strongly developed at the N ashaquitsa Cliffs, and on the 'Massachusetts mainland thick beds are found at Highland Light on Cape· Cod; at many points on the coast between 

Orleans and Chatham; at Indian Head, southeast of Plymouth; at Third Cliff, Scituate; and 

beneath the drumlins in Boston Harbor. It reaches a maximum thickness of about 100 f~et. 

Boston Harbor appears to mark the northern limit of the clay, although -a stratigraphically 

higher cl.ay with a different fauna extends north along the Marne coast and beyond. It is not 

known whether the absence of the clay north of Boston is due to nondeposition or to erosion 

by Montauk ice. 

JACOB SAND. 

The Jacob sand seems to have been originally rather widely distributed, but it was much 

more generally removed by the Montauk ice invasion than the underlying formations. A 

:f.i.ile clayey sand of the Jacob type is found, however, on Block Island, overlying the supposed 

equivalent of the Gardiners clay in the vicinity of .Clay Head and Balls Point. At N ashaquitsa 

Cliffs, Marthas Vineyard, the Jacob horizon is represented by alternating clays, sands, and 

gravels; on Nantucket it is represented by the gray clay and sands furnishing an extensive 

fauna at Sankaty Head; and at Highland Light, Cape Cod, it is represented by fine, mealy 

yellow sand. 

MANHASSET FORMATION. 

Herod gravel member .. -The Herod gravel member of the Manhasset formation appears 

to be one of the most extensive of the Pleistocene deposits, a gravel resembling it apparently 

outcropping nearly everywhere from Long Island to the vicinity of Boston, including Block 

·~ 

(_ 
Approximate correlatrom of the Pleistocene fo7'11UJ.lrom of Long Island with deposits of other areas. 

Long Island. 

I 

New Jersey. Supposed time 

Indian Hill, Plymouth, Boston Harbor and vicinity, Mas.<a- Northeastern New England equiva. 

Fishers Island, N.Y. mock Island. R. I. Marthas Vineyard, Mass. Nantucket, Mass. Elizabeth Island, Mass. West Barnstable, Mass. Buu.ards Bay, Mass. Truro, Cape Cod, Mass. Chatham, Mass. Manomet Hill, Plymouth, Mass. Ients in Mass. chusetts. (Clapp). the MissisStage. Substage. Origin. Represented by- Position of ice front. .Altitude or land. -· Nonglacial formations. Glacial deposits. sippi and 

Ohio valleys, etc. 

Hill inner Thin sheet of mominal Relatively thin mominal Thin to fairlfa thick bowlder Thin sandy till with bowl- Thin sandy to elayey till; Thin sandy to clayey tW; Thin sandy till with scat- Sandy till, with some bowlders; thick- ''Trenton gravels." "' Upper part 

Harbor Hill moraine and asso- At Harbor or ders; in places represented of till Harbor HiU. ciated till and outwash. moraine. drift. Absent. Absent. Absent. drift; numerous bowlders. tiU, in pares with mo- solely by scattered bowl- in places only scattered thickness locally; in places tered bowlders. · ness unknown, hut probably small :§ sheet. Early About 20 feet lower rainal topography. ders. bowlders. has morainal topography. = W Is- Wisconsin. Glacial. than at present. Superficial mantle of poatdnnnlin till. Older Wisconsin drift. Lower Cape May ·; cons in. I 

from I terrace of Dela- Lower part 

Ronkonkoma. Ronkonkoma moraine and asso- At Ronkonkoma or outer Undifferentiable from Relati,·ely thin mantle of Moraine and outwash plains. Momineand outwash plains. Undirterentiable from Undifferentiable from U nd i He reo tiable from Und Hferen ti:lblc U nd iffe re n tia bl e from Undifferentiable from Undifferentiable from younger drift. 

I ware Valley. 

~ of till 

ciat.ed till and outwash. moraine. younger drift. morainal drift. younger drift. younger drift. y(moger drift. younger drift. younger drift. younger drift. sheet. 

Great erosion unconformity; 350- Peorian 

foot submarine Hudson chan- . Clays overlapping upon lower slopes u Led a clay." Erosion interval (?) 

nel; channels (later) of Long of drumlins. between ~her ---- Island Sound and of sea hot- No evidence of any op- A bout 350 feet higher and lower ape Iowan Vineyard. Interglacial. tom off Montauk; and Vine- proach of ice near enough than at present. Erosion unconformity. Erosion unconformity. Erosion unconformity. Erosion unconformity. Erosion unconformity. Erosion unconformity. Erosion unconformity. Erosion unconfollllity. Erosion unconformity. Erosion unconfonnity. Erosion unconformity. 

N:~\~~~Ta1~ Erosion interval. (?) I yard formation, consisting of to be marked by deposits. 

I 

fossiliferous sands and muck ley. ---- peaty deposits, etc., in burieci Erosion unconformity. Erosion unconformity. Sanga· valleys; soil zones, etc. mon(?) 

' 

, . 

~foot terrace(?). Probably north of Long About 40 feet lower Questionable terraces Not recognized. Possibly the 40-foot terrace Not recognized. Not recognized. Not recognized. Imperfect terrace remnants Not recognized. Low, imperfect terraces. " Island Sound. than at present. at about 40 feet. near Vineyard Haven. at about 40 feet. ~ Hempstead. Hempstead Not definitely recognized; Local gravels. Glacial. Possibly some of wash lines on drum- 100 feet of stratified and un- ~ gravel Near north coast of island in probably sparingly devel- lins. stratified gravels. .2 member. u~y:fe~~nhasset east; alon5 scarp between About 100 feet lower Possiblr some local Gravel on east and south Plateau of north coast (Tis- G~~~ o/bt~tff~f n~~f~er~ Uppermost of the pre-W is- Up~r gravels beneath mo- Gravels of upper terrace or oped locally. ,., upper an lower Manhas- than at present. grave patches. coasts. bury terrace of Wood- cousin gravels. rame. plateau (100 to 125 feet). :!0 feet or graveL Gravels of plateau bordering shore. • worth). part of island. :>: 

I set plateaus in west. 

~ u Read vance and At south shore or beyond. folding. Higher Cape May terrace of the 

Temporary reccs- Delaware Val~ 

North or Shelter Island and Banded till or poorlh as- Probably the heavy tHis, Manhasset. ley; higher (::0 Illinoian. sian (local depo- "Middle Island belt." Heavy banded till near Clay Banded rbbly--clay till (re- Banded rbbly-clay till (re- llam1ed pehtly-e}ay till (ro- Banded jbbly--cl~y till (re· Heavy bowlder till at beach level MontaLJktill sition of gravel). 75 to 100 rect lower Local deposits of Banded till in bluffs of sorted gravels in luffs which in places form hills Till sheet beneath "Led a to CO feet) tcr- Montauk. GlaciaL member. than at present. banded tilL Head, Balls Point, and north coast. near Saokaty Head and worke material from worke material from rising above the sands and worked matQrial from worke matenal from Banded pebbly-clay layer. near Manomet; bowlder till forming lireater part of the dmmlins. clay"; most of drumlins. races of H.arit.an west of Southeast Light. northward. older formations). older formations). gravels. older formatioqs). older formations). bluffs west of Rocky Point. Ray, etc, 

First advance 

(folding of older Near Bethpage in west; be- beds and de~ yond south coast in east. sition of thick 

till). 

About 75 feet below Folded gavels present lo- Cut out by ice erosion un- Cut out locally by ice erosion In Long Island Sonnd, prob- present level in 

Herod. Glacial. Below sea level alon~ coast but m:lf. Herod gravel member. ably near north coast of early part of stage; Folded gravels. Folded gravels. Folded eravels. Disturbed gravels. cally; some places cut conformity along coast; Probably below sea level. Thick sands prest:nt locally. Sands and gravels in bluffs. unconformity but prob- Gravels beneath drumlins. Thin gravels (10 feet.). out by ice eroston uncon- Erobably present in high- ably present in places rise to a considerab e height in h' . island. above sea level at fonnity. ands of interior. along coa.st. times. 

Probably south of the head- Probably about 20 Thin yellowish sand alter- Clayebesands and fossilifer- Possibly some of clays on Not separable frqm the un- Not separable from the un- Not separable from the un- Below sea level along coast; probably Not seen; generally below sea level; 

Jacob. Transitional. Jacob sand. waters of Connecticut feet above present Gray clayey sands. Thin buff sands. Not seen. Not seen. Burgess Neck and in val- Eossibly represented by fossiliferous Absent. 

River. level. nating with clay laminre. ous dsat Sankaty IIea.d. ley of Monument River. derlying clay. derlying clay. derlying clay. occurs in hill. eds encountered in wells. 

Erosion interval and Erosion interval. Yar~ 

Dark g'Cfu to black cl:J; Probably represented by Fossiliferous clays of outer harbor re- stream deposits. mouth. 

the blue clay formerly ex- T~;or~~Js r!~~~i~ t~~ tbe~ Possibly some of clafis in No traces of ice within drain- About 50 feet above Chocolate, gray, and near y Head, B Dark gray to black clay at posed bcnc.ath the fossilif- Probably occurs just below Thick dark fu~ to black T~f{~k gr~fa ~r re~~f i~ Gray clay, with small ~uartz Below sea level along coast; probably worked into drumlins; fossiliferous Gardiners. Interglacial. Garcliners clay. age areas of streams enter- present level. red clays. Point, Black Rock Point£ Nasha~uitsa and locally erous beds at Sankaty the reworked clays at or a clay pit are probably ~~eb~lo~- ~aml~~-~l ~1;~ clays in b u 8 at light- anticlinal folds ~ng coast pebbles constituting ower occurs in hill. blue clay beneath drumlins at Great Absent. 

ing Long Island Sound. and west of Southeas on nort coast. head and by the blue cla(.s little below sea leveL Gardiners day. where. house. (east). part of clay beds in bluff. Head, etc. Light. reported below sea leve . 

30 feet of sand and fine 30 to 50 feet of granitic 30 to 50 feet of gravel be- Probably represented by Probably in Long Island 150 feet or more below Below sea level if pres- ~vel near ClaJ Head, .Below sealevel along coast; probably Possibly some of gravels reported in Pensauken formation. Kansan. Jameco. Glacial. Jameco gravel. Sound or vicinity. present leveL ent. lis Point, an west of gravels at· Nashaquitsa Below sea level. Below sea leveL Below sea leveL Below sea :level. neath above-described Below sea level. Gravels. occurs in hill. harbor wells. some of the prodrumlin 

Southeast Light. cliffs. clay at lighthoUse. tills. 

4,800± teet above 

Great erosion unconformity; present level(?). 

nearly complete removal of 

thick Mannetto gravel; cutting Cretaceous Unconformity (land 200 feet Erosion interval and Post-Mannet.to. of outer snbmarine valley and 700± feet above pres- Unconformit-y below Unconformity at top of Cre- Unconformity ::tt top or Cre- Unconformity below sea Unconformity below sea Unconformity below sea Unconformity below SD:1 Unconformity pelo\': SC2 Unconformity below sea Unconformity bclo·w sea Unconformity probably above sea Unconfonnitf at top of Erosion intcn·al. Aftonian, Interglacial. canyon and of rock gorge of No evidence of ice. eat level. sea level. taceous. taceous. level. level. level. level. level. level. level. le\·el but not exposed. (recognize( in borings). or more higher than at pres- stream deposits. 

Hudson River; excavation of ent). 

Long Island Sound (principal 

stage). Slightly lower than at present. 

··~ 

~\ The thickness of Pleistocene stratified Mannetto gravel probably present 

Probably about 200 Probab~ cut out by depoSits in this hill exceeds com- above Cretaceous at Scituate. Probably represented by Pre- Mannetto. Glacial. Mannetto graveL Probably in Long Island feet below present post· annetta ero- Absent; probably cut out Absent; probably cut out Probably cut out by post- Probably cut out by post- Probably cut out by post- Probably cnt out by post- Probably cut o4t by post- Probably cut out by post- Probably cut out by post- bincd post-Manne~to f'!rmations; greater part ofpredrumlin Bridgeton formation. Jerseyan drirt. Kansan. Sound or vicinity. by post-Mannetto erosion. by post-Mannetto erosion. Mannetto erosion. Mannetto erosion. Mannetto erosion. Mannetto erosion. Mannetto erosipn. Mannctto erosion. Mannetto erosion. level. sian. Cretaceous either nses high abovo Possibly represented by weathered till. 

sea or Mannetto gravel is present. and oxidized tills of interior. I ·-~ --~--

1629°-14. (To face page 220.) 
CORRELATIONS OF THE LONG ISLAND PLEISTOCENE FORMATIONS·. 221 

Island, the Rhode Island coast, Elizabeth Islands, Marthas Vineyard, Nantucket, Cape ·cod, 

and the Massachusetts coast as far as Marshfield and Scituate. The member appears to be 

represented by the stratified sands and gravels found beneath some of the drumlins on the 

shores and islands of Boston I-Iarbor and by similar materials found here and there beneath 

the thick till along the coast of New I-Iampshire and Maine. These deposits reach a thickness of at least 100 feet in places, generally constituting a large part of the bluffs at the Rhode 

Island and Massachusetts localities mentioned. North of Boston their thickness is greatly 

reduced, 10 feet being ·a common maximum, and at many points the gravels are absent. As 

on. ~ong Island, most of the deposits of the Herod horizon have been extensively folded, and 

.many of them have been eroded, presumably by the Montauk ice. 

Montaulc till member.-The Montauk member of the Manhasset formation is the most 

persistent <;>f the Long Island deposits. On Block Island what appears to be the till phase 

of the Montauk is even better developed. than on Long Island, constituting a heavy folded 

bed in the cliffs near Chiy I-Iead and Balls Point and forming a large part of the bluffs west of 

Southeast Light. On Marthas Vineyard a similar till is seen at several points· in t.he bluffs 

on the north shore. Similar conditions exist in Nantucket, although the till phase does not 

see.ln to be strongly represented. On Cape Cod it is found mainly in the form of reworked 

clay (probably Gardiners clay) from older formations, with a ·few pebbles and bowlders incorporated in it. The best localities for observing the deposit are at the West Barnstable clay 

pits in the Chatham region and on the west side of the cape near Wellfleet. On the main-coast 

however, the development seems to be much stronger, the till being a thick sheet filled with 

bowlders, giving rise to the bowlder pavements near Manomet Hill~ south of Plymouth, and, it 

is believed, to the till hills and big drumlins of the Boston region. In northeastern New England 

it apparently continues to be the principal till, ranging from 20 to 300 feet in thickness. The 

. invasion in New England, as on Long Island, seems to have been dual, the first advance depositUlg the greater part of the material and the second advance accomplishing most of the foldfug. 

In fact, the later advance is in some places represented solely by its erosion unconformity. 

The folding is characteristic of the advance throughout, being found in northeastern New 

England as well as on Long Island. 

Hempstead gravel member.-The Hempstead gravel member of the Manhasset formation 

is limited as a continuous deposit to the western half of Long Island but seems to be developed 

as an interrupted sheet along the coast throughout New Engla~d. Gravel of this horizon 

is seen above the supposed Montauk till member on both the east and south co~ts of Block 

Island; it caps the bluffs at many points on the north coast of Marthas Vineyard; it occurs 

above the fossiliferous beds at San~aty I-Iead, Nantucket; and it is seen at numerous places 

on the Elizabeth Islands and Cape Cod and along the Massachusetts coast to Plymouth and 

beyond. It is also found in New Hampshire and Maine above drift correlated with the Montauk member, in places teaching a thickness of over 100 feet. 

VINEYARD EROSION INVERV AL. 

The extensive erosion unconformity developed in the. stage following the deposition of 

the I-Iempstead gravel member of the Manhasset formation, is fully as well developed in southern 

New England as on Long Island, the terraces of Block Island, Marthas Vineyard, Nantucket, 

Elizabeth Islands, Cape Cod, and the :Massachusetts coast showing substantially the same . 

deep stream cutting previous to the deposition of the -Wisconsin till as is found between Manhasset Bay and Port Jefferson on Long Island. North of Boston little erosion occurred in 

early Vineyard· time. largely because of the submergence which continued through a considerable 

part of the stage and during which the "Leda clay" of the Maine coast was deposited. In the 

later part of the stage, however, a considerable uplift accompanied by erosion appears to 

have occurred in northeastern ~ ew England. 
222 GEOLOGY OF LONG. ISLAND. 

WISCONSIN DRIFT. 

The Wisconsin till sheet forms a mantle over the whole of New England essentially the 

same as on Long Islartd. On the whole it seems to be but little better developed than on the 

island, although in some places it reaches a somewhat greater thickness. F. G. Clapp 1 gives 

- its maximum thickness in northeastern New England as 20 feet, which is about the same as 

the average in southern New England and Long Island. 

CORRELATION WITH THE NEW JERSEY NONGLACIAL FOitMATIONS.2 

GENERAL CONDITIONS. 

The .conditions in New Je.rsey were so unlike those on Long Island and the nature of the 

depos~ts is so different that with the information at present available the correlations are of 

necessity doubtful, except perhaps in the vicinity of Staten Island. In the Long Island region 

the ice advanced with a long front facing the· sea, into or along the borders of which it emptied 

its debris-laden waters. ln New Jersey, on the other hand, the ice margin lay well back from 

the coast and its till and outwash accumulated on the surface of the land. The ice was not 

the only source of the material in the New Jersey region nor was the vicinity of the ice margin 

the only place of deposition. The Cretaceous and Tertiary highlands were everywhere being 

cut down and their materials were being deposited along the valleys, which in places were 

aggraded to elevations of 150 to 200 feet above the sea level. 

CORRELATIONS. 

. The chief Pleistocene deposits of New Jersey and their correlation with the deposits of 

Long Island are shown in the table facing page 220. · . 

Lower Gape Jfay terrace.-The lower Cape May terrace is composed of a quartz or granitic 

gravel, locally somewhat sandy, occurring as a low terrace about 20 feet above Delaware River. 

Trenton "Trenton ravels"' 

'",Sea .. le"Ye~ 

~-------------------~-----------------------------------------------------

FIGURE 205.-Diagram showing the relations of the higher and lower Cape May terraces to the so-called "Trenton gravel" along Delaware 

River in New Jersey. · · 

below C~mden, as a broad, ·flat terrace bordering the sea at about the .same elevation at Cape 

May, and as similar terraces in the reentrants of Raritan Bay and elsewhere. Along the Delaware it rises upstream, apparently rising above the higher Cape May terrace beyond Trenton 

and merging into the so-called "Trenton gravels," a local development of the Cape May formation. The relations appear to be as shown in figure 205 and would point to the completion of 

. the valley phase o_f the Cape May in late Wisconsin time. The marine phase, however, seems 

to be somewhat older, apparently antedating the Wisconsin outwash, as no traces of it are found 

on Long Island, although. the conditions were presumably as favorable for its formation as at 

the typical-locality on t4e shores of Raritan Bay only a few miles away. The writer believes 

that the Delaware development of the Cape May corresponds with the great outwash streams 

of the Harbor Hill substage and regards the marine phase as having been developed at a some.:. 

what earlier stage, supposedly contemporaneous with the cutting of the great inland scarp 

bordering the Harbor Hill moraine from Brooklyn to beyond Jamaica. 

Higher Gape May terrace.-The deposits of the higher Cape May terrace are more quartzose 

than those of the lower terrace and carry a greater percentage of iron crusts from the Pensauken 

formation. Along the Delaware Valley they include a considerable admixture of northern 

material, including fresh subangular grani.tes, but in the tributary streams and coastal phases 

1 Bull. Geol. Soc. America, vol. 18, 1908, table opp. p. 512. 

2 In studying the correlations the writer spent several days in going over the best New Jersey localities with Mr. G. N. Knapp, of the New Jersey 

Geological Survey, in 1903, and two weeks in company with Dr. H. B. Kiimmel, State geologist, in 1907. ·Cordial thanks are due for the many 

courtesies and the valuable assistance received from the State Survey during these visits. 
CORRELATIONS OF THE LONG ISLAND PLEISTOCENE FORMATIONS. 223 

the materials are wholly of local derivation~ The higher Cape May terrace has a maximum 

elevation of 40 to 60 feet on the borders of Raritan Bay, ·along the New Jersey coast, and in the 

open Delaware Valley, but may rise to considerably higher levels in the tributary valleys. 

Inasmuch as the granites of the deposits are fresh, whereas in ~he next older formation (the 

Pensauken) they are invariably weathered or rotten, it seems likely that the higher Cape May 

terrace of the Delaware Valley corresponds with the Manhasset formation of Long Island, in 

which the pebbles are likewjse fresh. No deposit is known on Long 'Island with which the 

higher terraces of Raritan Bay and the coast can be correlated, unless it may be the 40-foot 

terraces (I-Iempstead gravel member) on the Montauk peninsula. 

Intermediate stream deposits.-Deposits of locally derived gravels have been formed mainly 

in the valleys cut in the underlying Pensauken by tributary streams entering the Delaware 

trough. They are lower than the Pensauken and higher than the uppermost Cape May, and 

represent the deposits of the intervening stage, constituting a subaerial formation probably 

contemporaneous with the marine Gardiners clay of Long Island. · 

Pensauken formation.-The principal development of .the Pensauken formation is in the 

great trough in the Cretaceous deposits extending across the State from Raritan Bay to Trenton 

and down the Delaware Valley to Salem County. In this region the formation is commonly 

an arkosic ferruginous sand or quartz gravel containing numerous pebbles of rotten red shale 

and deeply weathered granites but no fresh pebbles. The formation in the tributary valleys 

and along the coast is composed of local n1aterials derived largely from the Bridgeton formation. 

In the trough rnentioned the formation attains a maximum altitude of 150 to 200 feet, but 

.along the coast it stands at about 90 feet. In general it lies in troughs or valleys eroded in the 

Bridgeton formation. 

The presence of bowlders apparently ice rafted along the Delaware belt suggests that it 

was forined during an ice advance, but there are many diffic;mlties in the way of definite correlation with the deposits of Long Island. Weathering is, on the whole, distinctly more 

advanced in this formation than in most of the :Manhasset of Long Island, although not more 

than in cer·ta~n phases such as those at Lloyd Neck (p. 136). According to the sequence of 

events it should be correlated with the J arneco gravel, but a ·grave difficulty is encountered 

in the fact that the upper surface of the J ameco is 50 feet or more below sea level, and that 

of the Pensauken formation along the coast is at least 90 feet above it, although the localities 

are only a few miles apart. The J ameco is a glacial formation and may have been deposited 

at son1e depth below the sea while the nonglacial Pensauken formation was accumulating at a 

considerable elevation above it. Such an origin of the J ameco demnnds a subsidence, as the land 

stood considerably higher both immediately before its formntion (ns shown by the post-Mannetto 

erosion valleys) and- imn1edintely after it (ns indicated by the marsh deposits and the shallowwater fnuna of the Gnrdiners clay). Unles$ nnother glncial stage is introduced, of which there 

is no other indication, there seems· to be nothing besides the J nmeco with which the Pensauken 

can be logically correlated. In being a vnlley formation in an erosional depression of an older 

surface, it agrees with the Jameco. 

Bridgeton formation.-The Bridgeton formation is lnrgely a cross-bedded quartzose gravel 

of the Mannetto type, with son1e rotten cherts and granites, and wns developed over extensive 

upland areas in southern, centrnl, and nort4ern New Jersey. It was nfterwards .largely removed 

in the centrn1 part, where it is now found only as caps on the higher hills. In elevation it varies 

from 100 feet at the southern lirnits t.9 200 feet in Camden County. Its habit is the same as 

that of the Mannetto gravel of Long Island, the formation occurring as a broad, sloping terrace, 

which as a rule covers and obliterates the underlying Cretaceous uplands of New Jersey in 

the same n1anner as tp.e Mannetto gravel covers the Cretaceous relllllants in the Mannetto 

I-Iills of' Long Island. The character of the Bridgeton formation and its position in the Pleistocene series are so similar to those of the Mannetto grnvel that its correlation with the Mannetto 

seerns reasonably certain. The two forinations are probably contemporaneous with the extramorainal drift farther north in New Jersey. 

• 

INDEX . 

A. 

Ackno\vlcdgmcnts to those aiding ............................... . 

Albertson, record of commission's test well near ................. . 

Alluvial phase of Long Island geology ........................... . 

Page. 

149 

4-5 

Page. 

Central Islip, confluent fans near ................................. 36-37 

Manhasset formation near. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118 

Channels of streams, deposits in.................................. 177 

Channels, outflow, formation of.................................. 47 

Amagansett, Manhasset and outwash topography neai;, plate 

showing ............................................. . 118 

outwash, formation, types, and relations of .................. 48-51 

5 

sections of, figure showing .............................. :. 50 

Amphitheaters, formation of. .................................... . 

formation of, figure showing ................................. . ~ terraced, sections of, figure showing.......................... 49 

Clapp, F. G.,acknowl~dgments to............................... 3 

plan of, figures showing ..................................... . 51 Clays, movements of, a cause of landslides........................ 56 

B. 

Babylon, channel near ............................................ · 175 

outwash near .•............................................. 173-174 

Backbone of the island, nature of................................. 1 

Baiting Hollow, Montauk till member near ................. , ... 138-139 

Montauk till member ncar, figures showing ................ 126,139 

Bald Hill, morainal character of.................................. 33 

Barnum Island, section near, figure showing....... . . . . . . . . . . . . . . 93 

Basal clays, application of the term.............................. 67 

Bayside, record of commission's test well near ................. :.. 149 

:Beaches, cmmecting, location of. ............................... 178-179 

formation and location of. ................................. 177-178 

marshes behind ................ : ............................. · 184 

south shore, formation· or..................................... 29 

Bedrock, position of, in western Long Island, map showing...... 66 

Bethpage, Cretaceous exposure at................................. 72 

Manhasset formation near.................................... 118 

Mannetto gravel near......................................... 82 

termccs of the Herod gravel member at ................ , .... 126-127 

Bibliography.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-20 

Bluffs, shore, character and examples of. ......................... 54-55 

Bowlder beach, typical, of North Fluke, plate showing........... 162 

Bowlders, decomposed, example of, plate showing. . . . . . . . . . . . . . . 82 

largc,occurrenceof ..................................... 170,171-172 

Bowman, Isaiah, acknowledgments to............................ 3 

Brentwood, Manhasset formation near............................ 118 

Bridgehampton, kettle valley and kettle chain ncar, plate showing. 42 

Manhasset formation near.·................................... 119 

record of Sanford & Son's well at............................ 75 

Bridgeton formation, correlation of............................... 223 

B rightou Beach, location of ............................ , . . . . . . . . . 178 

Broken Ground, landslide at..................................... 56 

landslide area at, plates showing ........................... 54, 55,56 

Mmmetto gravel at........................................... 83 

Brooklyn, Bartlett St. and Flushing Ave., record of -ivcllat ...... 86-87 

Brooldyn Aqueduct and New York Ave., record of test well 

No.3at .............................................. 87 

confluent fans in ............................. :............... 37 

Meeker and Kingsland avenues, record of well at............ 73 

modified scarps near, plate showing.......................... 52 

outwash in................................................... 173 

section in, figure showing..................................... 89 

Wisconsin till in . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160 

Brown Hills, Gardiners clay at................................... 98 

Jacob sand in .................... ~........................... 110 

figures showing ......................................... 109,110 

section at, figure showing..................................... · 98 

Browns Point, sections ncar, figure showing...................... 93 

0 c. 

Capo May terraces, correlations with ........................... 222-223 

relations of, to '!'renton gravels, figure showing............... 222 

Carmans River outwash channel, description of .... '.............. 176 

profile of, figure showing .............................. :...... 168 

Center Island, Cretaceous outcrops on............................ 70 

Centerport-Babylon channel, description of....................... 175 

162!)0 ....:....14--16 

Cold Spring, outwash near....................................... 173 

Cold Spring Harbor, Cretaceous deposits.on. .. . . . .. . . . . . . . . . . . . .. 70 

Cretaceous deposits on, section of............................. 70 

Monta~ till member near................................... 137 

section near, figure showing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96 

Wisconsin till near.............. . . . . . . . . . . . . . . . . . . . . . . . . . . . 161 

College Point, Hempstead gravel member near, probable deposit of............................................... 152 

Jacob sand at................................................ 108 

Montauk till member near .... -............................... 135 

figure showing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135 

record of railroad test boring near. . . . . . . . . . . . . . . . . . . . . . . . . . . . 131 

Compression of beds, possible mode of, figure showing............ 202 

under ice load, ligures illustrating............................ 204 

Connecticut, material from ................. 81, 88, 95, 123, 134, 15i, 159 

Connetquot channel; description of.. ........................... 175-176 

Cora~, dunes near............................................... 182 

Montauk till member near................................... 141 

·wisconsin till near........................................... 162 

Crane Neck, Montauk till member on .......................... 137-138 

Creedmoor, erosion scarp near, plate showing..................... 52 

Harbor Hill moraine near, plate showing ....... .'............. 32 

Cretaceous deposits, age of........................................ 77-79 

character of. ................................................. 67-68 

depth to, in eastern Long Island.............................. 76 

dip of........................................................ 76 

distr_ibut.ibn of. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69-76 

elevation of surface of, in western Long Island, map showing... 76 

excavation of Long Island Sound in .......................... 57-60 

folding and faulting of.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 

~ossils in ............. 1 ••••••••••••••••••••••••••••••••••••••• 77-79 

mtluence of, on the compression of overlying deposits, figure 

showing.............................................. 204 

on the topography. . . . . . . . . . . . . ... . . . . . . . . . . . . . . . . . . . . . . . . 29 

occurrence of ................................................ . 

on Lloyd Neck, plate showing .............................. . 

relation of Long Island Sound to, map showing ............. . 

surface of ................................................... . 

54 

56 

59 

77 

\lnconformablecontact of, with Hempstead gravel member, on 

Little Neck, Huntington, plate showing.............. 152 

valleys in ................................................... . 

Cretaceous formations, clays of, at base of landslip mass, plate 

showing ............................................ . 

on Little Neck, plate showing ........................... . 

columnar section of, figure showing ......................... . 

distribution of, on Western Long Island,map showing ....... . 

44 

55 

82 

67 

69 

Cretaceous time, events of........................................ 193 

D. 

Dall, ,V. H., acknowledgments to ............................... . 

Deltas, nature and occurrence of. ............................... . 

Diluvial phase of Long Island geology ............................ . 

Dix Hills, Cretaceous exposure in ............................... . 

Mannetto gravel in ........................................... · 

Mannetto valleys in .................. , ...................... . 

Wisconsin till near .......................................... . 

Wisconsin till on old graYels in, plate showing .............. . 

225 

3 

177 

5-6 

71 

82 

45 

162 

162 
226 INDEX. 

Page. 

Dolomite, Stockbridge, occurrence of ..... _ ..................... _ 66 

Dosoris Pond, record of D. F. Bush's well near ............... :... 104 

Douglaston, Manhasset plateaus near, figlp"e showing.. . . . . . . . . . . . 30 

mud cones around springs near, plate showing. . . . . . . . . . . . . . . . 183 

Drainage system, hypothetical, figures showing ........... : . . . . . . 35 

Drift phase, early, of Long Island geology........................ 9-15 

later, of Long Island geology...... . ............... _ ......... 15-19 

Duck Pond Point, Herod gravel near, figure showing............. 126 

Montauk till member near................................... 140 

figures showing............................ . . . . . . . . ... 126, 140 

section east of................................................ 140 

Dunes,character and distribution of. ........................... 180-183 

marshes among· ............................. ___ .............. 184 

near Friars Head, plate showing............................. 34 

E. 

;Easthampton, dunes at.............. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181 

Manhasset formation near..... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119 

Eastport, great bowlder near ................... :................. 165 

East River, channel of, how produced.. . . . . . . . . . . . . . . . . . . . . . . . . . . 24-25 

East Williston, Montauk till member at, probable bed of......... 141 

record of commission's test well near. . . . . . . . . . . . . . . . . . . . . . . . . 149 

section in clay pit at. ..................................... ,.. 141 

Eaton Neck, Cretaceous outcrops on.... . . . . . . . . . . . . . . . . . . . . . . . . . 71 

· Gardiners clay on, possible exposure of.. . . . . . . . . . . . . . . . . . . . . . 97 

Jacob sand absent from ............................... :...... 109 

Manhasset plateaus, figure showing........................... 31 

Mannettogravelon.... .. . . ... . . . . . .. . . . . . . . . .. . . . . . . .. . . .. ... 83 

Montauk till member on and near............................ 137 

figure showing .............................. _ . . . . . . . . . . . . 97 

record ofL. A. Bevin's well on ...... ___ ....................... 74 

section north of, figure showing ......... _.................... 97 

Elm Point, Cretaceous outcrop at:............................... 68 

~~~::: :i:z~~t~~:;:~~~~~-~f_._-_ -_ ~::::::::::::::::::::::: :·::::::::: 1~: Erosion by·the 11ontauk ice sheet................................ 200 

early Pliocene, summary cf. ........................... ·_..... 194 

post-Lafayette, evidence cf................................... 195 

summary of. .................... _........................ 195 

post-Mannetto, summary cf. ............................... 196-197 

pre-Wisconsin scarp form,ed by, plate s::owir: g. . . . . . . . . . . . . . . 52 

Recent scarp formed by, plate showing ..... _ ..... :........... 52 

Vineyard, summary of. .................................... 208-209 

·Exogyra costata, occurrence of................................... 7 

F. 

Faceting, pebbles showing ................................... ·- 122,127 

Fans, alluvial, nature and occurrence of.......................... 177 

compound, character and examples of........................ 37 

profile of, figure showing.................................. 37 

confluent, formation and examples of ........................ 36-37 

simple, formation of. ............ · .................. ·........... 36 

Farmingdale, Cretaceous exposure at.............................. 72 

Mannetto gravel near . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82 

~ar Rockaway, record of James Caffery's well near ..... ,......... 87 

Far Rockaway Beach, location of................................ 178 

;Field work, periods of. ... ~ ....................................... 1-2,3 

Fire Island Beach, description of. .............................. 177-178 

erosion of. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178 

Fishers Island, Gardiners clay on ..................... -.-- ...... 101-102 

Gardiners clay on, sections of, figures showing .............. 101,102 

Herod gravel member on ....... :............................. 130 

figures showing ................................ 101,102,130,147 

index map of................................................. 101 

Jacob sand on................................................ 112 

figures showing ................................ 101,102,112,147 

Montauk till member 0::1...... .. . . .. . . . . .. . . .. ... . . ... . . .. ... 147 

figure showing........................................... 147 

:Folding during Montauk substage, causes and character of ..... 201-207 

Folding by the Wisconsin ice sheet, figure showing............... 210 

Fort Salonga, section on coast near, figure showing............... 125 

Fosse channels, parallel, on Montauk peninsula, plate showing... 34 

Fosses, morainal, formation and varieties of ...................... 47-48 

morainal, profiles of, figures showing ......................•.. 47,48 

Fossils in the Gardiners clay ......................... ·- ......... 105-106 

in the Jacob sand .......................... _,_ ......... 111,113-114 

:Fresh Pond Landing, kettle valley near, plate showing . . . . . . . . . . 42 

1.!:anhasset formation near... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117 

Page. 

Friars Head, dunes near, plate showing. ____ ._._ ......... __ ._._.. 34 

Hempstead gravel member near ..... _........................ 153 

figures showing .......... _ ...... ___ ................. _ . . . . 153 

Herod gravel member near, figures showing ............. _ .. 126,153 

Montauk till member ncar, plate showing.................... 114 

G. 

Gardiners Bay, for.mation of. ............. _ ....................... 27-28 

Gardiners clay, age of. .......................................... 104-106 

character of. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . 93-94 

correlations ot ....................... _ . . . . . . . . . . . . . . . . . . . . . . . 220 

distribution of.. ....................... _ ..................... 96-104 

fossils in ............................ _ ........ : .......... 104, 105-106 

on Gardiners Lland, plate ~howing ... ___ .... ~ ........ ~....... 110 

origin of name of. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92 

relation of, to older deposits ........ _ ... _ . . . . . . . . . . . . . . .. . . . . . 94 

source of materials of ............... _ . . . . . . . . . . . . . . . . . . . . . . . . . 94 

structure of ................. : .......................... ~ . . . . . 95-96 

thicknesJ of.................................................. 104 

upper contact of, character of... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95 

wells penetrating ........................................... 102-103 

Gardiners interglacial stage, events of. ......................... 197-198 

Gardiners Island, fossils on .................................... ·. 113-114 

Gardiners clay on ............................. -. . . . . . . . . . . . . . . 100 

sections of, figure showing............................... 100 

plate showing.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 

Hempstead gravel member on................................ 156 

figure showing........................................... 146 

Herod-gravel member on ............................ ,........ 129 

figures showing................................. 100, 110, 129, 146 

Jacob sand on ........................................... _., 110-111 

figures showing ..................................... 100,110.129 

plate showing .......................................... ·_ . -110 

J ameco gravel on, possibility of..... . . . . . .. . . . . . . . . . . . . . .. . . . . 89-90 

Montauk till member on .............. _._-_ ....... :............ 146 

figures showing ......................................... 100, 146 

section near Cherry Hill Point..... . . . . . . . . . . . . . . . . . . . . . . . . . . . 105 

section on, near Eastern Plain Point, figure showing ..... ____ 95 

section on northeast shore of, figure showing.................. 90 

Wisconsin till on ........................................... 162-163 

Geologic features, list of. .............................. : ........ 185-192 

Geologic map, character of....................................... 65 

Glaciation, Hempstead, summary of............................. 208 

Jameco, summary of......................................... 197 

Mannetto, summary of. .................................... 195-196 

Montauk, summary of.. .................................... 199-208 

Vineyard, summary of ..................................... 208-209 

Wisconsin, sketch ·map showing extent of ......... _.......... 210 

Wisconsin, summary of. ................................... 209-212 

Glen Cove, Cretaceous outcrop at................................. 69 

Montauk till member near .................... : ............ 135-136 

figure showing ............................ :. . . . . . . . . . . . . . 108 

record ofF. E. Willets'swellnear............................ 132 

Gneiss, Fordham, occurrence of. .................... _............ 66 

Gravels on Lloyd Neck, plate showing ... _ ............ _. _ .. _ .... _ 136 

Great Neck, Huntington, Cretaceous outcrops on................. 71 

Mannetto gravel on ................................. _........ 83 

till moraines on ........................................ _ .... _ 35 

Great Neck, North Hempstead, Hempstead gravel member on... 152 

Herod gravel member on..................................... 125 

Manhasset formation on .............................. _ .... _ _ _ 115 

Montauk till member on .................................. _._ 135 

topographic map of. .......... ·................................ 30 

Great Peconic Bay, formation of. ........................... _ ..... 27-~8 

Great South beaches, dunes of..................................... 181 

Greenport, Montauk till member near ........................ _. 140-141 

Montauk till member near, figures showing ............ 110, 126, 140 

record of well of Greenport waterworks ........ ,.............. 75 

Gull Island, record of United States Army well on . . . . . . . . . . . . . . . 91 

H. 

Halesite, record of well of Huntington Light & Power Co. near . . . . 87 

Half Hollow Hills, Manhasset formation in....................... 118 

Mannetto gravel in........................................... &2 

Montauk till member in, probable deposit of.................. 141 

Hallock Landing, Gardiners clay near, evidence of ................ 97-98 

Herod gravel member near, figure showing ........ _,......... 126 

Jacob sand near ........................................ _..... 109 

figure showing ........................................ ___ 109 
INDEX. 227 

Page. 

llal!ock Landing, section \vest of, figure showing.. . . . . . . . . . . . . . . . 98 

Hampton Beach, description of. ............................... 177-178 

Harbor Hill moraine, bowldery part of, plate showing............ 32 

character and source of material in........................... 169 

distribution or ............................................. 169-172 

origin and extent of.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168 

outwash plain along, plato showing.......................... 32 

profile of, figure showing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 

Hauppauge, moraine near, plate showing........................ 34 

Hempstead glacial substage, events of............................ 208 

Hempstead gravel member, age of............................... 157 

character of. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150 

Page. 

Jacob Hill, Jacob sand at and near ............................. 109-110 

figures showing ...... .' ...................... :. . . . . . . . . . . . . 109 

Jameco gravel at, possible occurrence of ....... : ............ ,. 89 

section near, figures showing ................................. 95,98 

Jacob sand, age of.. ............................................ 113-114 

character of ........................... ·. . . . . . . . . . . . . . . . . . . . . . . 107 

correlations of. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220 

distribution of. ............................................ 108-113 

fossils in ................... • ............................ 111,113-114 

on Gardiners Island, plate showing........................... 110 

relation of, to older deposits ............................... 107-108 

source of. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107 

distribution or ............................................. 151-157 structure or. .............. :· ...................... :........... 108 

position of................................................... 115 wells penetrating ........................................... 112-113 

relations of, to older deposits................................. 159 Jaeob transitional stage, events or................................. 198 

tmconformable contact of, with Cretaceous deposits, plate Jamaica, outwash near........................................... 173 

showing............................................. 152 till moraine ncar, plate showing.............................. 32 

wells penetrating ............... : .......................... 156-157 Jameco glacial stage, events of.................................... 197 

Hempstead Harbor, Cretaceous outcrops near.................... 68 Jameco gravel, age or............................................. 92 

Gardiners clay at.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96 character of. ................................................. 85-88 

Herod gravel member near................................... 125 correlations or. ............................ · ............... _.... 220 

Jacob sand ncar.............................................. 108 distribution of.. .............................................. 89-91 

Manhasset formation near.................................... 116 origin of name of............................................. 85 

Manhasset plateaus near, plate showing...................... 32 relations of, to older deposits ............ ,.................... 88 

1-fmmctto gnwel near.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 structure of. ................................................. 88-89 

section north of Weeks Point on, figure showing............. 108 wells penetrating ....................................... : ..... 9Q-91 

Hempstead, Manhasset formation in ............................. · '118 Jameco time, subsidence in ..................................... 218-219 

outwash near................................................ 173 Jamesburg loam, deposits resembling .......................... 172,173 

Hempstead Plains, outwash character of......................... 37 Jolmson, B. L., acJ.."Jlowledgments to............................. 3 

structure of.. .............................................. 167-168 Jolmson, D. W., acknowledgments to ...... :..................... 3 

Hempstead time, UJ?lift in ..................................... ~. 219 cited ......................................................... 42-43 

Herod glacial substage, events of................................. 199 Jones Beach, location of.......................................... 178 ' 

subsidence in......................... . . . . . . . . . . . . . . . . . . . . . . . 219 

Herod gravel member, ago of..................................... 132 

character of, in Central and 'Eastern Long Island .......... 122-123 

in Western Long Island ................................ 121-122 

distribution of ............................................. 125-132 

on Gardiners Island, plato showing ........................... · 110 

position of. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115, 121 

pse~llobedding in, figure showing............................ 122 

relation of, to other deposits.................................. 124 

section of, near Quince ~L'ree Landing, fi~;,rure showing......... 124 

structure of .. ·. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . l24 

wells penetrating .................................. · ......... 13Q-132 

Herod Point, Herod gravel member near, figure showing......... 126 

Hewlett Point, record of G. B. Wilson's well near................ 1~2 

Hleksville,eonfluont fans near................................... 37 

High Hill, morainal character of... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 

. relation of, to the Uonkonkoma moraine .................... ~ 164 

History, geologic, outline of. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102-219 

Hog Creek Point, I:I01npstead gravel member near............... 155 

Hempstead gravel member near, figures showing .. 128,142,1-13,155 

Montauk till member near ........... ~ ..................... 142-143 

figures showing.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142, 143 

Hog Neck, Gardinors Clay on, evidence of........................ 99 

Jameco gravel on, possible occurrence of...................... 89 

Montauk till member on..................................... 142 

Hollick, Arthur, acJo:10wledgnumts to ........................... . 3 

Hooks, formation of............................................. 179 

Hoppers. See Amphitheaters. 

Hudson lUver, rock channel of, origin of. ........................ 62-64 

rock cha1111el of, probable depth or... . . . . . . . . . . . . . . . . . . . . . . . . 61 

submarine cham10ls of, cross section of, figure showing....... 61 

description of. ..................................... '. . . . . . 61-62 

map showing .......................................... .". 60 

relations of, figure showing............................... 61 

Huntington, Manhasset formation near.......................... 116 

outwashnoar ................ _ .............................. 173-174 

I. 

leo, shove and drag by .......................................... 34-35 

Isabella Beach, section of, figure showing........................ 102 

Islets, joining of, to main island ................................ 17S-179 

J. 

Jacob Hill, Gardiners clay at ................ · ............. .'....... 98 

Hempstead gravel member near.............................. '154 

figures showing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154 

HerJ,l gravel member near, figures showing ................ 109,143 

K. 

Kettle chains, ncar Bridgehampton, plate showing............... 42 

examples of.................................................. 42 

northwest of Riverhead, plate showing....................... 42 

icettle channels, character of ............................ :........ 47 

character of, figure showing................................... 47 

Kettle plains, character and e..xamples of...... . . . . . . . . . . . . . . . . . . . . 43 

profile of, figure showing..................................... 43 

Kettle valleys, branching, example of, plate showing . . . . . . . . . . . . 52 

example of, near Bridgehampton, plate showing............. 42 

near Fresh Pond Landing, plate showing................. 42 

formation and examples of. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42-43 

formation of, figures showing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 

northwest of Riverhead, plate showing....................... 42 

Kettles, double, e..xamples of..'.................................... 42 

elevated rims of, formation of..... . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 

formation of, figures showing ............................ 41,174 

from buried ice blocks, formation of...... . . . . . . . . . . . . . . . . . . . . 39 

formation of, figure showing.............................. 39 

from projecting ice masses, character of ............... , ....... 39-43 

formation of.. ......... , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 

figure showing........................................ 39 

slopes of sides of. ...................... :.................. 39 

figure showing .................. ·...................... 39 

marshes in. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184 

of doubtful origin, examples of. .............................. 43-44 

of the Manhasset surface, formation of. ....................... 35,44 

of the outwash deposits, character and varieties of. ........... 39-44 

of the stratified moraines, character of. ....................... 38,39 

of the till moraines, character of.............................. 38 

origin and varieties of. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38-44 

relation of channels to ...... :................................. 49 

terraced, formation of. ........................................ 4G-41 

formation of, figures showing ............................. 40,41 

typical forms of, examples of................................. 40 

L. 

Lafayette formation, deposition of ............. · ................. 194-195 

evidence of................................................... 80 

Lake Ronkonkoma, topographic features near, plate showing..... 46 

Landslides, area of, at Broken Ground, plates showing ....... ~ 54, 55,56 

causes and examples of.. ..................................... 55-56 

displacement in, figure showing... . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 

Lattingtown, Cretaceous outcrop near............................ 69 

Lignite, occurrence of. ........................................ · 103,106 

Literature on Long Island, periods of............................. 4-20 
228 INDEX. 

Page. 

Little Neck, Huntington, Cretaceous deposits on.:............... 71 

Cretaceous claYs on, plate showing. . . . . . . . . . . . . . . . . . . . . . . . . . . 82 

Hempstead gravel member on ................... ·............. 153 

figure showing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153 

Mannetto gravel on. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 

Montauk till member on ...... -............................... 137 

unconformable contact between Hempstead gravel member 

and Cretaceous deposits on, plate showing ........... . 

LittleNeck Bay, Herod gravel member·west of ................. . 

Wisconsin till near .......................................... . 

152 

125 

161 

Little Peconic Bay, formation of ................................. 27-28 

Lloyd Beach, section north of.................................... 83 

Lloyd Neck, clays on, section of................................. 97 

Cretaceous deposits on . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70-71 

plate showing ........................................ :... ·56 

section of... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 

Gardiners clay on, possible exposure of. ................. : .... 96-97 

gravels on, plate showing..................................... 136 

Hempstead gravel member on .............................. 152-153 

figures showing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152 

Jacob sand absent from...................................... 109 

Page. 

Mannetto glacial stage, events of. ........................... , .. 195-196 

interglacial period following, events of. ............. ." ....... 191i-197 

Mannetto gravel, age of.......................................... 85 

character of ........................................ ~ . . . . . . . . . 80 

correlations of. ............................................. 219-220 

table showing............................................ 220 · 

distribution of. .............................................. 81-85 

hills of. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 

orig.ill of name of. .......................... :. . . . . . . . . . . . . . . . . 80 

relations of, to older deposits ............ :.................... 81 

figure showing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 

structure of. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 

topography of, plate showing................................. 32 

valleys in .............. : . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44-45 

wells penetrating............................................. 84 

Mannctto Hills, Manhasset formation near. . . . . . . . . . . . . . . . . . . . . . . 118 

Mannetto gravel in........................................... 82 

valleys in. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 

region of, topographic map oL.... .. . . . . . . . . . . . . . . . . .. .. . .... 28 

Mannetto plateau, remnant of.................................... 30 

Mannetto time, subsidence in. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 217-218 

Manhasset plateaus near, figure showing .................... . 31 Marine deposits, kinds and occurrence of ....................... 177-180 

Mannetto gravel on ......................................... . 83 Marl, beds containing, section of................................. 68 

Montauk till member on ..... _._ ............................. . 136 

figures showing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136, 152, 153 

plate showing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136 

Wisconsin till on, plate showing.............................. 136 

Lloyd sand, application of the term.............................. 67 

Long Beach, location of.......................................... 178 

record of well of Long Beach Association at .................. 73-74 

Long Island, cross sections of, figure showing .................. ~.. 120 

form of. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-24 

agencies producing....................................... 24 

geologic map of. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . In pocket. 

geologic relations· of. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 

index map showing ......................................... . 

location of. .................................................. . 

north-south profile of, figure showing......................... 22 

topographic map of. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . In pocket. 

Long Island City, Wisconsin till in ...................... _-_ ..... 160-161 

Long Island Sound, Cretaceous structure and submarine channels 

of, map showing..................................... .59 

development of. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56-59 

later channels m.-- -------- ___ . ___ -------.- .. -.. -.. --·--- ----- 58-60 

Luce Landing, Herod gravel member ne:tr, figure showing........ 140 

Montauk till member near ................................. 139-140 

figures showing .................................... 109,140,154 

section east of ....................... :. . . . . . . . . . . . . . . . . . . . . . . . 139 

M. 

Manhasset formation, belts formed by .......................... 119-121 

correlations of .......................................... .- . . . 220-221 

distribution of ........................... _·_ ................ 115-121 

folded beds of, plates showing ........................... : .. 114, 152 

older valleys in.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45-46 

origin of name of. ............................. , ............ 114-115 

plateaus of. ... · ............................................... 30-31 

figures showing ................................ : ......... 30, 31 

source of material of. ....................................... 123-124 

topography.,formerl by, figure showing....................... 22 

plates showing ......................................... 32, 118 

wells penetrating.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119 

Manhasset glacial stage, events of.. ............................. 199-208 

Manhasset Neck, Hempstead gravel mBmber OIL................. 152 

Hempstead gravel member on, figure showing............... 135 

Herod ·grayel member OIL..................................... 125 

figure showing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135 

Manhasset formation on ............................. ,........ 115 

Mannetto gravel on . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82 

Montauk till member on.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135 

figure showing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135 

retreatal deposit on.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176 

topographic map of.......................................... 30 

undermined peat on, plate showing.......................... 182 

Manhasset plateau, figures showing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22, 30 

plate showing................................................ 32 

Manhattan Beach, location of.................................... · 178 

Marshes, fresh, formation of. ................................... 183-184 

produced by damming streams............................... 183 

salt, formation of ........................................... 184-185 

Mather, W. W., cited ............................................ 6,185 

Mattituck, kettle valley near, plate showing...................... 52 

Manhasset formation near.................................... 117 

Mattituck Inlet, former character of.............................. 28 

Melville, Cretaceous exposure near. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 

Cretaceous exposure near, section of..:....................... 72 

Mannetto gravel near........................................ 82 

marly beds near, section of................................... 68 

Melville channels, description oL......................... .. .. . . . 175 

Middle Island, Manhasset formation near......................... 117 

topographic features near, plate showing..................... 116 

Wisconsin till near ............ : ....................... ·....... 162 

Mill Neck, Cretaceous outcrop on................................ 70 

Miller Place, end of the Manhasset plateau near.: ............. , . . 116 

Miocene deposits, evidence of.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80 

Miocene time, events of. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194 

Montauk, bluff section near "First House" at... . . . . . . . . . . . . . . . . . 156 

Montauk glacial substage, events of. ............................ 199-208 

subsidence in. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . 219 

Montauk peninsula, fosse channels on, plate showing............. 34 

Hempstead gravel member on .............................. 155-156 

figures showing ............................ 143, 144, 151, 155,156 

Herod gravel on. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128 

figures showing ........................................ 124, 128 

Montauk till member on ................................... 143-145 

figures showing .......... 89, 99,124,128,143,144,145,151, 155,156 

section on, figure showing.................................... 151 

Montauk Point, Gardiners clay on. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99 

Jacob sand near ............................ ·.................. 111 

figures showing .................................. 89, 99, 107, 128 

Jameco gravel on, possible occurrence of...................... 89 

sections on, figures showing .............................. 89, 99, 107 

Montauk till member, age of. .................................. 149-150 

banded, near Friars Head, plate showing ........... :......... 114 

character of ................................................ 132-134 

contact of with Wisconsin till, plate showing................. 136 

distribution of.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135-149 

position of. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132 

rehition of, to other deposits.................................. 134 

section of, west of Hulse Landing. . . . . . . . . . . . . . . . . . . . . . . . . . . . 138 

source of materials of.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134 

structure of. -----------------------.----------------------- 134-135 

wells penetrating ..................................... : ..... 147-149 

Moraines, cone-shaped, formation of. ............................. 32-33 

cone-shaped, profiles of, figure showing.·..................... 32 

depressed, example of,near Hauppauge...................... 165 

9xample of, near Port Jefferson........................... 170 

near Port Jefferson, plate showing.................... 34 

nature of.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33-34 

relation to outwash, figure showing . . . . . . . . . . . . . . . . . . . . . . 31 

due to ice shove and drag, description of ..................... 34-35 

of sand and gravel, example of, plate showing................ 32 

.. 
.. 

INDEX. 229 

Page. 

Momincs, ridge-shaped, example or, plate showing................ 34 

ridge-shaped, formation or ........................•........ -- 33 

stratified, normal profile of, figure showing................... 38 

till, chamctor and varieties of. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34-35 

exmnplo of, plato showing................................ 32 

Mud cones near Douglaston, plato showing ........... .' ........ :.. 183 

Mulford Pcint, Jamoco gravel near, possible occurrence of........ 89 

N. 

Napoaguo 13oach, dunes at....................................... 181 

Now England, correlation witJ1 deposits in ..................... 219-222 

soutJ1ern, index map showing ........................ :....... · 1 

Now Jersey, Cretaceous deposits of, correlation with . . . . . . . . . . . . . 77 

nonglacial formations in, correlation with .................. 222-223 

Pleistocene deposits in, literature of ......................... 19-20 

Now Jersey State Geological Survey, aclrnowledgments to, note.. 222 

North Jnuke, bowlder beach of, plate showing................... 162 

Manhasset formation on...................................... 117 

outwash on.................................................. 174 

Wisconsin till ncar........................................... 162 

Northport, Cretaceous clays ncar, plate showing.................. 82 

Cretaceous outcrop ncar: .... ·................................. il 

Herod gravel member ncar................................... 125 

landslide area near, plates showing ........................ 54, 55,56 

Montauk till member near................................... 137 

figure showing........................................... 125 

North shore, contour of, cast of Port Jefferson.................... 27 

dunes of. • . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182 

1 Page. 

Pensauken formation, correlation with........................... 223 

Plain, confluent, formation of . . . . . . . . . . . . ....... .. . . . . . . . . . . . . . . . 37 

Plainview, Mannetto gravel near ............................... :.. 82 

Plants, salt-marsh, range of. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • . . 213 

Pleistocene formations, correlations of .......................... 219-223 

correlations of, status of...................................... 2-3 

in New Jersey,literature of .................................... 19-20 

record of .................................................... 8G-176 

Pleistocene time, events of. ...................... -.............. 195-212 

lengths of stages in ....................................... :. 216-217 

position of land· with reference to sea level in, figure showing. . 218 

Pliocene time, events of. ....................................... 194-195 

Plum Island, Gardiners clay on ................................ 10G-101 

Gardiners clay on, section of, figure showing.................. 101 

Hempstead gravel member on................................ 156 

figure showing ....... :................................... 146 

Herod gravel member on ................................... 129-130 

figures showing ..................................... 111,130,146 

Jacob sand on .... :........................................... 111 . 

figure showing............................................ 111 

Montauk till member 011. •••••••••••••••••••••••••••••••••• 146-147 

' figures showing .................................... 111,146,147 

record of United States Army well on . . . . . . . . . . . . . . . . . . . . . . . . lll 

Port Jefferson, depressed moraine near........................... 34 

depressed moraine near, plate showing....................... 34 

Hempstead gravel member near.............................. 153 

Manhasset formation near.................................... 116 

Montauk till member near................................... 138 harbors of, formation of ..................................... . 

original and present cross sections of, figure showing ..... . 

25-26 

26 outwash near ................................................ . 

185 plate showing ........................................... . 

174 

34 

161 n1arsbes of .. .' ............................................... . 

scarp of, formation of.. ...................................... . 25 'Visconsin till near .......................................... . 

25 Port Washington, folded beds of Manhasset formation near, plate successive forms of, figure showing .......... : ........... . 

Notched cliffs, production of. ................................... ·. 

profile of, figure showing .................................... . 

0. 

51-52 

52 

Oak Island Beach, location of.................................... 178 

Oregon IJills, Hempstead gravel member near................... 154 

Hempstead gmvcl member ncar, figure showing.............. 140 

Montauk till member in..................................... 140 

figure showing ........................................ ~.. 140 

Orogunic movements, Pleistocene and Recent, summary of ..... 217-219 

Outwash deposits, alongHarborHillmoraino, character of. ...... 172-173 

along Harbor Hill moraine, distribution of ................. 173-176 

plato showing............................................ 32 

along Uonkonkoma moraine, character and source of material 

in .... -- ...... -------- .. ------ .. -.-.----.----- .... -. 166-167 

distribution of. ........................................ 167-168 

relations of, to older deposits. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167 

channels in ................................................ 175-176 

extent and varieties of ....................................... 36-38 

near Port Jcfiorson, plato showing........................... 34 

secondary features of ......................................... 37-38 

topography of, ncar Amagansett; plate showing.............. 118 

near Southampton, plate showing........................ 118 

Oyster Bay, Hempstead grovel member near..................... 152 

Hem pstoad gravel mom bor near, figure showing.. . . . . . . . . . . . . 96 

Herod gro.vol member near................................... 125 

figure showing ........................ :.................. 12.5 

Jacob sand near.............................................. 108 

Manhasset formation nonr.................................... 11tl 

Manhasset plateaus near, figure showing...................... 30 

Montauk till member near ............................ ·....... 136 

figure showing........................................... 96 

Wisconsin till near........................................... 161 

P. 

Paino IJanding-, Herod gravel member near, figure showing....... 126 

Pal eon tologie phase, early, of Long Islm1d geology... . . . . . . . . . . . . . 6-9 

Patchogue, dunes near........................................... 182 

Peacock Point, record of C. 0. Gates's well near.................. 74 

Peat, occurrence of ............................................. 213,214 

undermined, on Manhasset Neck, plato showing.............. 182 

Peconic Bay, origin of ........................................... 27-28 

Peconic River, former course of................................... 28 

fosse position of. ................... ·_......................... 120 

Wisconsin till near........................................... 162 

showing ............................ : ................ . 

Jacob sand at ................................................ . 

114 

108 

record of well of Dodge estate near.... . . . . . . . . . . . . . . . . . . . . . . . 113 

Pre-Cretaceous rocks, character and occurrence of. ................ 65-66 

sections showing ............ ·................................. 66 

Pre-Cretaceous time,·events oL ................................. 192-193 

Pseudokettles, varieties of.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 

Pseudomoraines, character of.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 

example of, near Friars Head, plate showing................. 34 

. Q. 

Quaternary time, events of .................................... 195-219 

formations of. .............................................. 80-185 

n. 

Ravines, obstruction of... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 

obstruction of, figure showing................................ 52 

refilling of. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 

figure showing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 

Recent time, deposits of ....................................... 176-177 

erosion scarp of, plate showing............ . . . . . . . . . . . . . . . . . . . 52 

events of. .................. -................................ 212-216 

Heel Cedar Point, Gardiners clay near............................ 99 a 

Retreatal deposits, nature and occurrence of. . . . . . . . . . . . . . . . . . . . . 176 

Richmond Hill, confluent fans near............................... 37 

Riverhead, dunes near........................................... 182 

kettles south of. ............................................. 38, 39 

Manhasset formation near. . . • . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117 

marshes formed at. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183 

Montauk till member near. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139 

figures showing .................................... 109, 139, 153 

moraine southwest of, plate showing......................... 32 

outwa:sh deposits near........................................ 174 

peat deposits near ................ -.-- ........... _·_ .........• .-. 214 

Roanoke Landing, Hempstead gravel member near.............. 154 

Hempstead gravel member near, figures showing ........... 139,153 

Jacob sand near, figure showing.............................. 98 

Roanoke Point, Gardiners clay near, evidence of ............ :. _.. 98 

· Herod gravel member near, figure showing................... 139 

sections east of, figure showing............................... 98 

Robins Island, Gardiners clay on ................................ 98-99 

Hempstead gravel member on............................... 156 

figures showing ................................ : ... 145, 156,157 

Herod gravel member on ................................... 128-129 

figures showing ................................. 99, 110,127, 156 
230. ·INDEX. 

Page. 

Robins Island, Jacob sand on.................................... 110 

Jacob sand on, figures showing .............................. 99,110 

Manhasset formation on ................................... , 117-118 

Montauk till member on..................................... 145 

figure showing........................................... 145 

sections on, figure showing................................... 99 

Wisconsin till on ........................................... 162-163 

Rockaway Beach, location of.................................... 178 

Rockaway Ridge, gravel of.............. . . . . . . . . . . . . . . . . . . . . . . . . 127 

Manhasset formation on...................................... 118 

Rocky Point, Cold Spring Harbor, Gardiners clay on............ 96 

Rocky Point Landing, Gardiners clay near... . . . . . . . . . . . . . . . . . . . 97 

sections near, figures showing ............................... 97-210 

Rocky Point, north of Greenport, Hempstead gravel member near. 154 

section south of.............................................. 154 

Rocky Point village, Manhasset formation near.................. 117 

outwash deposits near....................................... 174 

Ronkonkoma moraine, character and source of material in ..... 163,164 

distribution of. ............................................ 164-166 

Ronkonkoma, Manhasset formation near......................... 118 

profile of, figure showing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 

relations of, to older deposits................................... 164 

Roslyn, Manhasset formation near................................ 116 

Montauk till member near.................................... 135 

outwash deposits near. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173 

Roslyn channel, description of.................................... 175 

s. 

Sag Harbor, Gardiners clay near.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99 

Hempstead gravel member ncar ............. ,................ 154 

figures showing ......................................... 154,155 

Herod gravel member near ................................. 127-128 

·sections of, figures showing ............................. 127,142 

Montauk till member near.................................... 142 

figures showing ......................................... 142,154 

Salisbury, R. D., cited............................................ ~61 

Sands, magnetic and garnetiferous, nature and distribution of. 179-180 

Sankaty beds of Woodworth and of V catch, difference between. . . . 92 

Scarp, great inland, of Western Long Island, character and origin of 53-54 

inner, in Broken Ground landslip area, plate showing......... 56 

modified, examples of, plate showing.......................... 52 

north shore, how formed... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 

i::~:~~l:~~;:~~~~~~~~~::::::::::::::::::::::::::::::::: .~; Scarps, inland, character and examples of......................... 53 

Scope of this report ............................................. 3, 20-22 

Scuttle Hole kettle valley, description of. .................. · ........ 42-43 

Sea Cliff, Cretaceous outcrops at................................... 69 

Sebonac Neck, Gardiners clay on.................................. 99 

Selden, dunes ncar .................... ."........................... 182 

semi dune surface near, plate showing..... . . . . . . . . . . . . . . . . . . . . . 182 

Shelter Island, Herod gravel member on, indications of............ 129 

Jacob sand on................................................ 110 

Manhasset formation on ..... ·: .............................. 117-118 

Montauk till member on, probability of. .................... 145-146 

Wisconsin till on ....................................... :. . . 162-163 

Shinnecock Bay, Herod gra:vel member near .................... 127-128 

sections in Herod gravel member near, figures showing. . . . . . 126, 127 

Manhasset formation near .................................. 118-119 

Shinnecock Canal, Gardiners clay near ...... :..................... 99 

. Hempstead gravel member near .................. 1•••••••••••• 154 

figure showing .............................. , . . . . . . . . . . . . 154 

Montauktillmembernear .................................. 141-142 

figures showing ......................................... 142, 154 

· Shi1mecock Hills, dunes at........................................ 181 

partiy morainal character of ... :............................... 35 

relation of, to the Ronkonkomamoraine..................... .. 165 

Short Beach, location of........................................... 178 

Smithtown, dendritic drainage system at.......................... 26 

Manhasset formation near .............................. .'...... 116 

outwash deposits near........................................ -174 

topographic features near, plate showing. . . . . . . . . . . . . . . . . . . . . . 46 

Smithtown Bay, Hempstead gravelmembernear................. 153 

Hempstead gravel member near, figure showing. . . . . . . . . . . . . . . 13 7 

Smithtown driftless area, location and features of ........ :......... 162 

Page. 

Smithtown harbor, hooked sandspitat entrance to, plate showing. 178 

South Fluke, Herod gravel member on ......................... 127-128 

Manhasset formation on...................................... 118 

'\Visconsin till on............................................. 163 

South shore, marshes of. ...... :·.· .......................... 183,184-185 

outline of. ... · ................................................. 28-29 

Southampton, outwash topography near, plate showing........... 118 

Spartina patens association, occurrence of.. . . . . . . . . . . . . . . . . . . . . . . 214 

Spit, hooked, at entrance to Smithtown harbor, pln,teshowing..... 178 

Spits, formation of. ............................................ 17i-178 

Springfield pumping station, well sections at..................... 87 

Springs, work of, in causing landslides ........................... 55-56 

Stony Brook, Herod gravel member near......................... 125 

. Herod gravel member near, figure showing................... 137 

Montauk till member near... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137 

figure showing.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137 

Stream channels, deposits in..................................... 177 

Subsidence, evidence of ........................................ 212-216 

in Mannetto time, summary of ............................. 217-218 

in Pleistocene stages, fig~re showing......................... 218 

T. 

Terrace, profile of, figure showing................................ 208 

Tertiary time, deposits of. ......... : ............................. 79-80 

events of. ................................................. 194-195 

Thomaston, Cretaceous outcrop at............................... 68 

Till, kettle rim of, figure showing ....................... •.......... 174 

Montauk, banding of. .................. :..................... 200 

moraine of, near Jamaica, plate showing...................... 32' 

Till sheet, character of ............................... '. . . . . . . . . . 158-159 

distribution of. .................................. : ......... 160-163 1 

figure showing·relations and structure of. . . . . . . . . . . . . . . . . . . . . . 160 

ridge of. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161 

source of material of. ................................... .: ... 159-160 

Topography, significance of ...................................... 22-23 

'l'renton gravel, relations of, to Cape May terraces, figure showing .................................... :.............. 222 

u. 

United States, eastern, physiographic provinces of, map showing. 2 

Uplift, Pleistocene, figure showing............................... 218 

post-Mannetto, summary of.................................. 212 

v. 

Valley Stream, section near, figure showing...................... 89 

Valleys associated with the moraines, varieties of. ............... 46-48 

Valleys, difference in steepness of banks of ....................... 50-51 

difference in steepness of banks of, figure showing. . . . . . . . . . . . 50 

hanging, production of ......... ·.............................. 52 

production of, figure showing............................. 52 

Mannetto, formation and examples of ........................ 44-45 

north shore, original and present cross sections of, figure showing................................................... 26 

post-Wisconsin, types and formation of. ...................... 51-52 

pre-Mannetto, influence of.. ....................... .'.......... 44 

Veatch, A. C., acknowledgments to ............................ :. 3 

Vineyard formation, character and occurrences of .............. 157-158 

Vineyard interglacial stage, correlations of........................ 221 

events of. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208-209 

w. 

Wading River, Manhasset formation near........................ 117 

Montauk till member near. . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . 138 

. figure showing........................................... 126 

Water, work of................................................... 212 

Waves, work of, in causing landslides............................ 55 

Wells penetrating Gardiners clay, list of ....................... 102-103 

Hempstead gravel member, list of............................ 157 

Herod gravel member, list of. .............................. 130-132 

Jameco gravel, list of. ........................................ 90-91 

Manhasset formation, list of.................................. 119 

Mannetto gravel, list of....................................... 84 

Montauk till member, list of.. .............................. 147-149 

West Hill, possible Cretaceous core of. . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 
INDEX. 231 

Page. 

·wost Hills, H. L. Stimpson's well in, samples fr01n.............. 84 

Wost Neck, Herod gravel member on ...................... :..... 125 

record or Mrs. M:. H. Clots's well on. . . . . . . . . . . . . . . . . . . . . . . . . . 113 

W110atloy, topography near, plato showing....................... 32 

' Wheatley Hills, Mannotto gravel in .... :......................... 82 

Mannotto valleys i11. .. • .. • .. .. .. • .. .. .. . . . . . .. . . . . . . . . . . • .. .. 44-45 

Win~~:t~~~~~~ f~~~~i-~_ :~~~-~:: :::::::::::::::::::::: :·::::: ::::::::: !i~ Wind deposits, character and distribution of ................... 180-181 

·winkle Point, Mannotto gravel ncar, section of................... 83 

Wisconsin drift, correlation of.................................... 222 

divisiollS of................................................... 158 

Wisconsin glacial stage, events of. .............................. 209-212 

Wisconsin till, banded, in Dix Hills, plate showing............... 162 

Page. 

Wisconsintill,contactor, with Montauktillmember,plateshowing. 136 

Wisconsin time, ~;~ubsidence i'n ...... ,............................. 219 

Woodhull Landing, Gardiners clay at, possible exposure of .. _.... 97 

Herod gravel member near................................... 126 

figure showmg ................................ : ...... :. . . 125 

section of, figure showmg. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125 

section at top or bluffs near, figure showing................... 210 

·woodville Landing, Jacob sand near............................. 109 

Jacob sand near, figure showing............................. 109 

Woodworth, J. B., cited........................................... 53 

Wyandanch, Cretaceous outcrops near ........................... 71-72 

Y. 

Yaphank, Manhasset formation near .............. ::............. 118 

0