DEPARTMENT OF THE INTERIOR 

UNITED STAT.ES GEOLOGICAL SURVEY 

GEORGE O'l'IS SMITH, DIRECTOR 

PROFESSIONAL PAPER 79 

RECURRENT TROPIDOLEPTUS ZONES 

OF THE UPPER DEVONIAN 

IN NEW YORK 

BY 

HENRY S. '\1ILLIAMS 

V\r ASHINGTON 

GOVERNMENT PRINTING. OFFICE 

1913 

CONTENTS. 

Introduction ............................................................................... .' ........... . 

Discovery of th·e recurrent Tropidoleptus zones ...................................................... . 

Nomenclature ...................................................................................... . 

Bearing of _the investigation ....................... ~ ................................................. . 

A~ea covered by the investigation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . ...................... . 

'J'he faunules ......................................... · ............ ' ............. , ... ~ .................... . 

Geographic distt·ibution ............................................................................. . 

Faunal lists ........................................................... · ............................. . 

:Faunal localities ................................................................................... . 

1'he recurrent zones ....... · .............. : ......... · ..... ~ .............................................. . 

Stratigraphic positions .............................................................................. . 

G·eologic sections .................................................................................. . 

Thickness of the formations ..... : ........................................................ · .... ~ ....... . 

Ji'auna of the several zones .............................................................................. . 

Grouping by faunules ......................................... · ..................... , ................ . 

Grouping by species and genera ..................................................................... . 

Evidence of recurrence ............................................................................. . 

Tropidoleptus zone No. 1 (Enfield shale member) ................... · .............................. . 

Tropidoleptus zone No. 2 (Cayuta shale membe..-) ....... : ......................................... . 

Tropidoleptus zone No. 3 (Cayuta shale member), .............. ·.: ................................ . 

~~::~~~~g~I;id~i~~tt;; .· ~ ~ ~ ~ ~ ~ : : : ~ : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : ~ Continuity of the genus ........................................................................ . 

Specific characters ............................................................................ . 

Fluctuating characters ................................................................ : . ....... . 

Status of fluctuating characters in zone No. 1 ............... .- .................................... . 

Specimens examined ........................ ~ .............................................. . 

External form of shell ...................................................................... . 

Pedicle valve ........... · ................................ , ................................... . 

Brachial valve ........................................................................... ~ .. 

Surface characters ........................................ · .................................. . 

Conclusions ................................................................................ . 

Status of fluctuating characters in zones Nos. 2 and :3 .......................................... · .•. 

Sp(lcimens examined ......................................................... , ............. . 

:E~xternal fonn ............................................................................... . 

Plications ..................................... · ............................................ . 

Brachial valve ............................................................................. . 

Conclusions ................................................................................ . 

Genus Rhipidomella ....................... : . ...................................................... . 

Occun·ence .......................................... ~ .......................... · .............. . 

Scope of investigation .................. · ...... · .................................................. . 

Selection of specimens ............................................................... .' ......... . 

Measurement of specimens ........................................ ; ............................ . 

Characters selected .................... : . .................................................. . 

Ratio indexes ............................................................................. . 

Shape of shell (expressed by index R!) ..................................................... . 

Size of muscular scar of pedicle valve (expressed by index H.Z) ................................ . 

Shape of muscular scar of pedicle valve (expressed by index R3 ) ••••••••••••••••.•••••••••.••.• 

,3 

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4 CONTENTS. 

Fauna of the several zones-Continued. 

Genus R~~pid?m~ll~-C?ntinued. . Specific discrimination ______ .... ___ .......... _ ......... __ .. _ ... _______ ... _______ . _ . _____________ _ 

Artificiality of present distinctions ........ ___ . _ ... _ .. __ ... _ . __________ ... _______ · .. ____ -- __ . __ _ 

Possible means of discrimination ....... ____ . _ .... _____ ...... ______ . ____________ . ____________ _ 

Pedicle area ..... : . ... : . ...... 1

• __ •• ____ .- ___ • ____ •.• ___ • _________________________________ _ 

Hinge teeth .................... ___ .. __________ . _____________________________________ ~ __ _ 

Median septum ................. ___ . __________ . _________________________________________ _ 

Muscular scars .................... ___ ....... ____ ....... ___________ ... _____ , ________ . ___ _ 

Interior 1narkings ............. ___ .... _____ . _ .. _______ ... _____ :· __ ....... _______________ _ 

Difference in convexity of valves .. ____ ...... ___ . _ ...... ____ . _________ . ________________ _ 

Thickening of the shell .. _ ...... ___ .. _ .. _______ . ________________________________________ _ 

Conclusions ................. ____ ... ______________________ . _________ . _______ . _______ . ____ .. __ 

S pirije1· marcyi . ............ _ ....... _ . _____ . _________________ . ___ . ________ . ___________ . ____________ . _ 

Differentiatiol'1. ....................................... _ ............... _ . _ ........... ___ , __ . _____ : _ 

Recurrence by zones ............................... _ . _______ ... _______________ . __ . _____________ _ 

~~~~t~~:~i~: ~~ !:~~::~:~ :z~-~~s-. ---- ~ : : : : : : : : : ·: : : : : : : : : : : : : : : : : : : : : : ~ : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 

Degree of fluctuation .................... _ ....................... _ . _ ........... _ . ___ . _____ . _ . _ 

In zones Nos. 1 and 2 ................................. _. _ ...................... __ . _. ________ _ 

In zone No.3 ....... : ................................................... ·_ ................... . Summ.ary .................. _ . __ ... _ .... _ ..... _____________________________________________ _ 

Laws of evolution expressed by the gens Spirijer marcyi ................... __ ..................... __ _ 

Evolution and classification .. ·: .......... _ .................. _ ......................... ~ .... _· __ 

Nomenclature adopted in this paper ......... _ ...... _ , ...................... _ . __ . _ . __ ....... __ _ 

Specific identity ........................ _ ............. _ . : .. __ ....... _ .. _________ .. __________ _ 

Criteria of classification ............................................................ _ ......... . 

Historical discrimination ............................ --. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .... . 

Differentiation by fluctuating characters ... _ ................................. ·_ ............... .. 

Degree of fluctuation ........................ ~ .. _·_ .. , .................................... . 

Measurement of fluctuations ............................................................ . 

Gosselet' s method .................... -_ ................. _ .......... __ ... ______________ . __ _ 

Application of Gosselet's method to Spirijer marcyi . ............................... ____ . __ _ 

Spirifer marcyi typicalis, alpha, and beta . ................................................. . 

Spirifer marcyi gamma .. , ..................................... _ .... _ ..... _ ..... __________ _ 

Spirifer marcyi delta . ........................... _ ...................... _ .... ________ . _ . __ 

~~~~~ :~~~~ ;~:~~~-·_ ~ ~ : : : : ~ : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : :·: : : : : : : : : : : : :: : 

The rudimentary syrinx .......... ·- ...................................................... . 

Occurrence ......................................................................... . 

Spirifer granulosus . ...................................................... _______ ... _ 

. ~::~;t~;;~~-~~~~--- -_::::: :·:::::::::::::::::::::::::::::::::::::: :.: :.::::::::::::::: 

Interpretation of the syrinx ...................................... _ ................... . 

Distribution of varietal forms .................... _ .... ___ .. __ ... : . _ ... ____ . _ . ___________ .. __ _ 

Stages in evolution ................................ _ ... _._ .. ___ ..... _. _______ . __ . ____________ _ 

Genus Delthyris ........................................ ________ .. __________ .: ______________________ -

~::~:~f :r:~!:~r~~~:~c-t~~~-- ______ · _-: : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : :, 

Genus CamarotCEchia ............................................... _ ........... _ .... _ .... ____ .... _. _ 

Specific discrimination ................................................ _ ...... _ ......... ___ .... __ 

Problem of recurrence .......................................................................... . 

Gen ';a~~~~~~~~~~~~~: _- _ ._ ._ : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : :· : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 

Specific characters of Cypricardella bellistriata ........... .......................................... . 

Hamilton forms ............................................................................. . 

Portage forms ............................................................ ·_ ................. . 

Chemung forms ............................................ .- ............................... . 

Summary .................................................................. _ ... _ . __________ _ 

European occurrence ........................ : ................... _ ..................... -........... . 

Tropidoleptus zone of the Ithaca shale member .............. ·_ .. .' ..................................... . 

Existence of the zones ............................ -.. ------- .. --------------------- .. -----------.--------

Reliability of the evidence ......... ~ .......... -- . -- -- - - -. -- - --- . -- . -- - - - -.. -.. -- . -........ -..... -- -- .. . 

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• 

CONTENTS. 

Existence of the zones-Continued. 

Examination of the fauntlles .. ________ ............................................................... . 

Diagnostic genera .. _ ............................................ ·_ .............................. ~ 

Associated species ........................ ~ ................................ , .................... . 

Evidence that the fauna is recurrent ................................................................. _ 

Criteria of recurrence ............................................................................ . 

\Vithdrawal of the fauna ... _·_ .......................................... ~ ............•.......... _. 

Return of the fauna ......................................................................... _ .. _ 

Absence of the general fauna in the Tropidoleptus zones ................................... __ .. 

Identity of the returning fauna .. __ ...... : .................................................. . 

~~~~ ~~~~~~~~~:~~) ~ .-.-. ~::::::::::::::: :·:::::::::::::::::: ~::::::::::::::::::::::::::::: Conclusions as to recurrence .................................................................... _ ... . 

Stratigraphic extent of the zones ................................................................... _ . _ .. _ 

Oscillation of the recurrent fauna .............. : .............................................. _·._ .......... . 

Significance of recurrent faun~s ...................................................................... _ ... . 

Diastrophisn1 ................................................................................... __ .. . 

Geologic evidences of diastrophism .............. ( ................ : ................................. _ .. 

Time relations of diastrophi~ ..................................................................... _ .. 

Lithologic evidence ............................................................................... . 

Faunal evidence ................................................................................ . 

Correlation of lithologic and faunal indications ................................................. _ .. _. 

Contemporaneity of deposition ................. -.- .................................................... . 

Lithologic evidence .............................................................................. . 

Faunal evidence ....................................... : ............................. · ........... . 

Composition of faunas ....................................................................... . 

Changes in faunas ............................................................................... . 

Hecurrence of faunas ........................................................................ . 

Index ..................................................................................................... . 

ILLUSTRATIONS. 

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Pa.gc. 

PIJATE I. TrOJ)idolcpttts carinatus (Conrad)................................................................. 86 

II. Tropidoleptus carinatus (Conrad)................................................................. 88 

III. Rhipidomella vanuxemi Hall and varieties .................. ·....................................... 90 

IV. Spirifer marcyi Hall and varieties ............ ,................................................... 94 

V. Spirifer and Syringothyris............ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96 

VI. Cypricardella bellistriata (Conrad) ...... : ................................ _......................... 98 

}i'IGUUE 1. Index diagram, showing distribution and method of locating faunules in the 15-minute quadrangles 

composing the Watkins Glen-Catatonk area ............... .' .................. _......... . . . . . . . . 9 

2. Faunal chart, showing the eastward invasion of the Portage and Chemung ·faunas and the westward 

invasion of the recurrent Hamilton fauna in the Watkins Glen and Catatonk quadrangles........ 23 

3. Sections at Taghanic Ravine, Glenwood, and Fall Creek.......................................... 24 

4. Section at Brookton .................................................... ·....................... 25 

5. Sections at White Church and Bald Hill, Caroline............................................... 25 

6. Section at West Danby ... ~ ...................................... :............................. 25 

7. Section at Spencer Lake ravine............................. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 

8. Section at Swartwood.......................................................................... 26 

9. Sections at Glory Hill and Waverly............................................................ 26 

10. Sections at North Candor, Catatonk, and Dean's tannery .............. _ .... _ ........ .'... . . . . . . . . . 27 

U. Sections at Hawley Hill; Water Street bridge, Elmira; Latty Brook; and Breesport................ 28 

12. Sections at East Branch, Cortland; Blodgett Mills; and Messengerville and East Virgil............ 29 

13. Sections at Marathon, Killawog, and Harford ....................................... :.............. 30 

14. Sections at Harford Mills, Lisle, and Berkshire ............ _._................................... 33 

15. Cross section of beak of Spirifer granulosus sigma, showing rudimenta-ry syrinx....... . . ... . . . . . . . . . . . 61 

16. Cross section of beak of normal Spirifer granulosus............................................... 61 

17. Cross section of beak of Spirifer marcyi sigma, showing rudimentary syrinx................. . . . . . . . . 61 

18. Cross section of beak of Syringothyris sp., showing complete syrinx ............................ ;.. 61 
• 
RECURRENT TROPIDOLEPTUS ZONES OF THE. UPPER DEVONIAN 

IN NEW YORK. 

I B:y: I-IENI~X 8. V\T ILLIAMS. 

INTRODUCTION. 

DISCOVERY OF THE RECURRENT TROPIDOLEPTUS ZONES. 

In preparing the data for the Watkins Glen-Catatonk folio/ the occasional finding of 

Ti'OJJidoleJJtus cm'inatus (Conrad) in strata far above the supposed range of the species or of the 

-fauna with which thespecies is nonnally associated led 1~1e to n1ake a critical search for that 

species and its associates and to observe and record the places in the sections and in the sequence 

of faunas where they appeared. The result wa$ 'the discovery of four zones, three well-n1arked 

and one subordinate, in the Upper Devonian .rocks, each of which contained several species 

that are conunon in the typical I-Iamilton for1nation of. the Ca.yuga Lake section and are associn.ted with very few of the really characteristic species of the faunas norn1al to the formatiohs 

in which they are found. One of the principal zones is in the upper n1e1nber (Enfield shale) 

of the Portage forn1ation, and the other two are in the lower part (Cayuta shale n1en1ber) of the 

Chennmg for1nation: The subordinate zone is near the base of the Ithaca shale mmnber of the 

Portage for1nation. (See fig. 2, p. 23.) 

NOMENCLATURE. 

These zones were called recurrent Tropidoleptus zones 2 because of the conspicuous presence of TropidoleJJtus carinatus in nearly every sample lot of fossils obtained from then1. Subsequently 3 I applied the names of Van Etten, Owego, and Swartwood to the three 1nost conspicuous zones. The less conspicuous zone :pear the base of the Ithaca shale member of the 

Portage forrn~tion I called the Ithaca recurrent zone. 

The United States Geological Survey is opposed to the application of geographic names to 

faunal zones, and accordingly in the Watkins Glen-Catatonk folio I called the three principal 

zones the first, second, and third Tropidoleptus zones. Although such usage in a scientific 

discussion of the faunas is open to the objection that, in the present state of knowledge, it is 

uncertajn whether the zones n1apped are the only recurrent zones of the kind in the series, yet 

iir order to preserve unifornuty in the nomenclature the same usage will be followed it} the present report, and the terms zones No. 1, No. 2, and No. 3 will be used to designate the recurrent 

zones at first called Van Etten, Owego, and Swartwocd, respectively. The subordinate zone 

will be called "the zone of the Ithaca shale member." 

BEARING OF THE INVESTIGATION. 

The iinportance of the investigation lies chiefly in its disclosures in regard to the ancient 

, geography of the region. Both the departure and the return of the fauna n1ust have been due 

to diastrophic changes that at one time brought ·about conditions unfavorable to the continued 

existence of the fauna and at another time not only restored favorable conditions but also 

provided 1neans for the renligration of the fauna into the region. Such changes may have 

resulted (1) fr01n the alternate closing and reopening of an actual passageway which alternately prevented and permitted the access of the fauna and of water~ favorable to them, or 

(2) fron1 changes that affected the direction, character, or vohune of existing ocean currents. 

1 Watkins Glen-Catatonk folio (No. 169), Geol. Atlas U.S., U.S. Geol. Survey, 1909. All references in this paper are to the field or octavo 

edition. 

2 Williams, H. S., On the classification of the Upper Devonian: Proc. Am. Assoc. Adv. Sci., vol. 34, 1885, p. 226. 

a Jour. Geology, vol. 14, 1906, p. 580; vol~ 15, 1906, pp. 9i, 108, 109. 

7 
\ 

8 RECURRENT TROPIDOLEPTUS ZONES IN NE·w YORK. 

AREA COVERED BY THE INVESTIGATION. 

The area covered by this investigation is included almost wholly in the Watkins Glen and 

Catatonk quadrangles mapped by the United States Geological Survey. These quadrangles lie 

in south-central New York, and each quadrangle comprises an area n1easuring 30 minutes 

from north to south and from east to west and covering one~fourth of a square degree. Each 

has been subdivided into four smaller areas, 15 minutes in extent, known as the Watkins, 

Elm~ra, Ithaca, Waverly, Dryden, Owego, Harford, and Apalachin quadrangles. For conyenience of reference in this paper each of these smaller quadrangles has been further subdiiVided into !-minute blocks, designated by numbers (1 to {5) from eas.t to west and by letters 

(A to 0) from north to south. The positions of all faunules and sections are given by reference 

to these !-minute blocks. (See fig._ 1.) 

THE FAUNUJ.-~ES. 

GEOGRAPmC DISTRIBUTION. 

In the work for this paper 1,411 separate faunules were collected and examined from the 

Watkins Glen and Catatonk qu~drangles and 103 more from the adjoining Cortland quadrangle. 

All the faunules which contained either Tropidoleptus carinatus, Rhipidomella vanuxemi or 

closely allied forms, Spirijer marcyi, Oypricardella bellistriata, Delthyris mesicostalis, Phacops 

rana, and other species either recorded in the Hamilton faunas· or closely allied to the1n were 

critically examined.· 

As the stratigraphic position of ~hese faunules was determined it was discovered that most 

of them were located in one or other of three definite zones in their.respective sections. It was 

also ascertained (1) that none of the species were found stratigraphically far above or below 

the i:r:nmediate zone~ in which they were often found in abundance and (2) that several of them 

associated together. 

After all the faunules of ·the quadrangles under investigation had been studied and stratigraphically located, the faunules in each section containing any of these species were grouped 

together to form what I designated recurrent Tropidoleptus zones, considering Tropidoleptus 

to be the most characteristic form. 

As the investigation proceeded I eliminated from the series all the faunules which did not 

cont~in at least one of the first four species mentioned above (all Hamilton species), regarding 

them all to be diagnostic representatives of the recurrent fauna. Those remaining constitute 

the 63 representative faunules of the recurrent Hamilton fauna listeg (pp. 11-23). All but 'One 

of them (No. 4 of the list) contain one of the first three species named. The fauna of No. 4 

contains Oypricardella bellistriata and is high up in the Chemung;' it was retained in the list 

because nowhere else in the Chemung has the species been recorded except in association with 

some one(} of the three diagnostic recurrent genera. 

All but 2 of these.63 sample faunules were collected within the Watkins Glen and Catatonk 

30-minute quadrangles. The two exceptions (Nos. 44 and 45) caine fr01n Blodgett Mills, in 

the southeastern part of the Cortland quadrangle, a few, miles north of the northeast corner of 

the Harford 15-minute quadrangle. The 63 include all the faunules discovered in the areas 

_containing the Tropidoleptus fauna. The distribution among the 15-nlinute quadrangles was 

as follows: 

Distribution of faunules by 15-minute quadrangles. 

\Vatkins ........................................... . 0 Owego ..... ·········-·······.................... 7 

Elmira ...... _·-._ .................... _ ............ . 5 Cortland. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 

Ithaca .............................................. . 3 Harford. -. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 

Waverly ........................................... . 17 Apalachin. .. .. . .. .. . . . ... .. .. . .. .. . . .. . .. . . . . . . . . 7 

Dryden ..... · ....................................... . ll 

63 

In the following list a serial number is given to each faunule for convenience of reference, 

and in the descriptions each is indicated by some ·geographic name (of a town, creek, or other 

natural feature) by which it may be located on a general map. It is further identified by its 
THE FAUNULES. 9 

field label which bears the nan1e (abbreviated) of the 15-nlinute quadrangle fron1 which it was 

taken, the designation by nun1ber and letter of the particular 1-n1inute block in that quadrangle 

in which it was found, the geologic section in that block and the particular stratum in that 

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section as recorded on the field notebook record of the collectQr ... The approximate altitude 

of the faunules above sea level and the zones which they are supposed to ;represent are also 

given. The altitudes were determined by 1neans of the contours on the topographic· atlas sheets 

and by 1neasure1nents fro1n the nearest bench mark, checked by aneroid barmneter. 
10 RECURRENT TROPIDOLEPTUS· ZONES IN NEW YORK. 

Faumtles of the recmrent Tropidolept·us fauna from .the Watkinf Glen and Catatonl.: 30-minute qnadrangles.a 

Locality. 

1 Breesport ..................... : ...... _. _. _ ........... _. _ .. _____ ...... . 

~ ·~~~~~~-:Bridge·.·.-:::::::::::::::::::::::::::::::::::::::::::::::::::::: 4 •... -.do ................................................................ . 5 Southport ............................ _ ... ____ ........... _____ . _____ . _ . _ 6 Ithaca ...................... ___ ..... __ . ."._ .. __ ... ___________ .. __ ._ ..... . 

7 West Danby ......................................... _ .. _______ ....... . 8 Cayuta ................ ____ . __ ..... ___________ .. _._. _________ ... _._ ... _ 

9 Spencer Lake ravine .................................................. . 10 ..... do ......................... ·._ ....... _ .. _ ... ______ .. _ .. : ........ _ .. . 

g • ~~l~~rH.iil:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: 13 Austin Hill .................... _ .. _ ........... _._. ___________ . ____ .... . 14 ..... do ......... : .......................... ______ ...... _ .. __________ ... . 15 · ..... do .......................................... _ .. __ . __ . __ ._ .. ______ .. 16 Van Etten ............................. _ ................. _ ...... _ ...... . 17 North Chemung ............ ~ ................. _ . __ ... _ ........ _______ .. 18 East Elmira ................... , ...... _._._ .. _ ...... _. ___ . __ . ___ . __ ... _ 19 Lockwood, east ..................... _ ......... _. ____ ........ _ ... ____ .. _ 20 Lockwood, west ...................................................... . 21 Narrow Hill .......................... _ .... _ ........ _ . _ . _ ..... _ . _ ..... _ 22 \Vavcrly ............................................ _____ . __ . __ . _ ..... . 23 ..... do ......................................... __ ....... _ .... _ .. ___ ... . 24 ..... do ............... ·' .............................. _._ ... ____ .. _ .... . 25 Glory Hill, Waverly.·.:·· ............................................. . 26 Mount Pleasant ....... ; .......................... _. _. _ .. _ ............ _ 27 Dryden Lake ......... · .................................... _ . _ . ___ . _ . , .. 

~g :::::·~~::::::::::::::::·::::::::::::::::::::::::::::::::::::::::::::::::: ,30 East Danby .................................................... _ ..... . 31 .. , .. do ................................................................ . 32 Bald Mountain................. . ................ _ ................... . 32a Bald Hill, Caroline ................................................... . 33 White Cli.urch ........................................................ . 

g: ~e~i~!rcgu~~};~ ·.:::::::::::::::::::::::::::::::::::::::::::::::::::::: 36 ..... do ................................. : .................. _ .. _____ .... . 37 North Candor ......................................... _._ .. _ .......... . 38 ..... do ................................................................ . 39 ..... do ........................................................ _ ....... . 40 Spencer, east ......................................................... . 41 _Owego ................................................•................ 

:~ · ost~~ri:: : : : : : ·: : : : : : : : : : : : : : : : : : : : : : : : : : :·: : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 44 Blodgett Mills ........................................................ . 

45 ..... do .................................................. ' .............. . 46 Messengerville ........................................................ . 47 ..... do ................................................................ . 

!~ il!~~;:<i M-ilis:::: ::: '::: ::: : :: : : : : :: : : : ::: : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 50 ..... do ....................................................... · ......... . 51 ..... do ................................................................ . 52 ..... do ................................................................ . 53 ..... do ................................................................ . 54 Center Lisle ........................................................... . 55 Lisle .................................................................. . 56 Berkshire ............................................................. . 57 Maine ................................. _ .. __ .. _ ... __ . _ ........ ___ .. ___ . 

~g ~~l~~~g~~~~~::: :·:::::::::::::::::::::::::::::::::::: :·::::::::::::::: 60 Apalachin ............................. _ .......... __ ............ _ ..... . 

~~ . ~-r-~% ~~-e-~: : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 63 Tracy Creek, southwest .............................................. . 

Label. 

Quad- l-~~~n­ rangle. block. 

El. 

El. 

El. 

El. 

El. 

It h. 

Ith. 

Ith. 

Wv. 

v.rv. 

''\'v. 

Wv. 

'Vv. 

''\'v. 

Wv. '''v. 

Wv. 

\1\'v. 

\J\Tv. 

Wv. 

\J\Tv. 

Wv. 

Wv. 

"\Vv. 

\J\Tv. 

Dr. 

Dr. 

Dr. 

Dr. 

Dr. 

Dr. 

Dr. 

Dr. 

Dr. 

Dr. 

Dr. 

Dr. 

Ow. 

Ow. 

Ow. 

Ow. 

Ow. 

Ow. 

Ow. 

Ct. 

Ct. 

Hd. 

Hd. 

Hd. 

Hd. 

Hd. 

Hd. 

Hd. 

Hd. 

Hd. 

Hd. 

Hd. 

Ap. 

Ap. 

Ap. 

Ap. 

Ap. 

Ap. 

Ap. 

1E 

20 

8J 

8J 

6L 

1E 

3K 

15N 

1A 

lA 

1B 

6B 

7B 

7B 

7B 

4D 

llH 

141 

3J 

4J 

9N 

40 

40 

40 

40 

9B 

3D 

3D 

3D 

llH 

llH 

7I 

81 

81 

121 

9J 

9J 

9A 

9A 

9A 

14C 

1I 

1I 

120 

8L 

8L 

5A 

5A 

8C 

130 

130 

130 

130 

130 

7I 

2J 

12L 

4D 

llE 

80 

13L 

5N 

6N 

60 

Collector's 

personal 

designation. 

la 

la 

4n 

ln 

lq 

la 

lg 

!a 

1l 

lvvv 

lb 

!a 

lj 

~j2 

lj3 

1a 

!a 

1d 

ld 

2a 

!a a 

1b 

lg 

1j 

2nn 

lee 

lj 

1l 

lo 

lb 

ld 

ln 

2a 

le 

4b 

lp 

a 

1l 

lm 

1 

ld 

ld 

lp 

1q 

1r. 

1f 

1a 

2a 

1k 

1q 

1r 

Is 

1v 

1a 

1e 

1l 

1g 

1a 

3a 

1 . 

lc 

lo 

4 

Elevation 

above sea level. 

Feet. 1,420 

1, 345 1,075 

1, 415-1,420 

1,000 410 

1,074-1,090 

1,444 

1,175-1,185 

1,565-1,570 

1,020 

1,561 

1,610 

1,610 

1,610 

1,030 

1,440 

1,500 

1,345 

1,339 

889 

850 

870 

885 1,165-1,170 

1, 405-1,410 

1, 685-1,690 

1,700 

1, 723 1, 475-1,485 

1, 495-1,505 

1, 778 1, 760-1, 767 1,300+ 

1, 375-1,395 

1, 273-1,288 

1, 288-1,298 

1,075 

1,095-1,102 

1,102-1,109 

1,025 

1,010-1,020 

1,010-1,020 

1,112-1,114 

1, 286-1,300 

1, 300-1,315 

1,045 

1,048 

1,800 

1,420 

1,470 

1,475 

1, 485-1,495 

1, 506-1,530 

1,410 

1,358-1,369 

1, 165-1, 170 1,041-1,055 

1,500 

1,514 

1,180 

1,300 

1,402 

1,600 

No.3. Do. No.2. 

No.3. 

No.2. 

Zone. 

In Ithaca shale member of Portage formation. 

No.1(?) .. No.2. Do. No.3. 

No.1. 

No.3. Do. 

Do. 

Do. No.1. 

No.3. Do. 

Do. 

Do. 

Do. No.2. Do. 

Do. No.3. 

No.1. Do. 

Do. 

Do. 

Do. 

Do. No.2. Do. No.1. Do. 

Do. 

Do. 

Do. 

Do. 

Do. 

Do. No.2. Do. No.3. 

In Ithaca shale member of Portage formation. Do. 

Do. 

Do. Chemung formation (?No.2). No.1. Do. 

Do. 

Do. 

Do. 

Do. 

Do. 

Do. 

Do. No.3. Do. Chemung formation (? No. 2). No.3. Do. 

Do. 

a Comprising the Watkins. Elmira (El.), Ithaca (Ith.), Waverly (Wv.), Dryden (Dr.), Owego (Ow.), Harford (Hd.), and Apalachin (Ap.) 

15-minute quadrangles. 'rwo faunules from the Cortland (Ct.) quadrangle, north of the Harford quadrangle, are included. 

FAUNAL LISTS. 

In the followillg lists are g!ven the names of the chief species detected by a preliminary 

examination of the specin1ens as brought in from the field. There are, doubtless, many other 

outcrops in the region which, upon examination, might show expression of... the same fauna. 

But the present set furnishes sufficient evidence to demonstrate the recurrence above the 

I-Iamilton formation of several zones, generally of very slight thickness, which contain representative species of the general I-Iami.lton fauna, often in great numbers, b.ut which contain 

few of the spepies :characteristic of the adjoining beds below and above the zones. 
THE FA UNULES. 11 

Some of tho lists do not include Tropidoleptus carinatus;· these were included in the series 

because of the presence of one or n1ore of the species conunonly found associated with Tropidoleptus in the other smnples, which gave ground for believing that in all probability further 

search will reveal Tropidoleptus also. 

Each faunule has been studied and its species listed. In making up the lists the names 

applied have been those of the species already described in the literature with which the speein1ens n1oro closely agree in their evident characters. here the agreen1ent is close the specific 

name is applied without comn1ent; where variational 1nodification is evident the fact is indicated by the prefix "cf." to the specific nmne; where the divergence is considerable the generic 

-nruno alone is used without tho specific nmno. 

FAUNAL LOCALITIES. 

1. Breesport.-Ono mile southwest of Breesport at forks of road; 3 or 4 feet of shaly 

sandstone; elevation, 1,420 feet above sea level (baron1etric). E. NI. Kindle, collector, notebook, 1903, p. 70. Tropidoleptus zqne No. 3 (Cayuta shale n1ember). Fauna (E~.l E, 1a): 

Rhipidomolla vanuxemi. Atrypa reticularis. 

Spirifer marcyi. Productella cf. rectispina. 

Schizophoria striatula. P. cf. hirsuta. 

:Leiorhynchus sinuatum. P. cf. boydi. 

Camarotrechia sappho. Delthyris mesicostalis. 

?Euomphalus. Modiomorpha sp. (small). 

Sphenotus sp. Chonetes sp. 

2. EZmi1·a.-Quarry 2 miles northeast of Elmira at r·oadside east of the ravine entering 

Latty Brook fron1 the northeast from the slopes of Maby Hill; shaly .drab-colored ~andstone 

and shale; elevation, 1,345 feet above sea level. E. :M. Kindle, collector, 1903, p. 74. Tropidoleptus zone No. 3 (Cayuta shale mmnber). Fauna (El. 2G, 1a) ~ 

Tl'Opicloleptus carinatus. Spjrifer marcyi. 

Rhipidomella vanuxemi. Nucula sp. 

Cypricardella bellistriata. Atrypa reticularis. 

Delthyris mesicostalis. Dalmanella cf. tioga. 

Camarotrechia sappho. Productella rectispina. 

Pleut·otoma.ria cf. capillaria. Chonetes. 

Leiorhynchus sinuatum. Modiomorpha. 

S. Fitches Br.idge.-Section a nTile west of Fitches Bridge, up the sides of the ravine; gray 

sandy shales and shaly sandstone; elev~tion, 1,075 feet above sea level (barometer). Original 

field No. 1172 N 4 • E. l\1. Kindle, collector, 1902, p. 17. Tropidoleptus zone No. 2 (Cayuta 

shale Jnmnber). Fauna· (El. SJ, 4n): 

Rhipidomella. vanuxemi. 

Cypdcardella bellistriata. 

Leiorhynchus mesicostale. 

Atrypa reticulads. 

Camarotrechia cf. contracta. 

DeUhyris mesicostalis. 

Po.lreoneilo bisulcatn. 

Chonetes scitulus. 

Macrodon chemungensis. 

Spirifer marcyi. 

Productella cf. speciosa. 

P. lachrymosa. 

Dalmanella tioga. 

Schizophoria striatula. 

4. Fitches Bridge.-Section up ravine, a 1nile west of Fitches Bridge, upper part; elevation, 

1,415-1,420 feet n,bove sea level. V. I-I. Bm·nett, collector, notebook 1, p. 35. Tropidoleptus 

zone No. 3 (Cayuta shal,e mmnber)., Fauna (El. SJ, ln): 

Cypricardella bellistriata (small). 

DeUhyris mesicostalis. 

Strophoclonta (Donvillina) cayuta. 

Schizophoria. striatula. 

Dalmanella. tioga. 

Atrypa reticularis. 

Orbiculoidea elmira. 

Ambocrelia umbonata (gregaria). 

Modiomorpha neglecta. 

M. cf. subalata. 

Spathello. sp.? 

Palreoneilo bisulcata. 

MacroQ.on chemungensis. 

Prod uctello. l~chrymosa. 
12 RECURRENT TROPIDOLEPTUS ZONES IN NEW YORK. 

5. Southport.-Quarry behind schoolhouse, 1 mile southwest of Southport (as given in 

notebook, 1902, p. 25); or, quarry 1! miles west of Southport just south of schoolhouse (as 

given in notebook, 1903, p. 82); about 8 feet exposed, dipping 1° to 2° S. Some beds split into 

thin smooth-surfaced flakes, but most of them are of soft shaly sandstone that tend to break 

very irregularly when exposed to weather. Elevation not given; probably about 1,000 feet 

above sea level. Original mark 1172 Q. E. M. Kindle, collector, 1903, p. 82. Tropidoleptus 

zone No. 2 (Cayuta shale n1ember). Fauna 1 (El. 6L, lq): 

Rhipidomella vanuxemi. 

Schizophoria striatula. 

Dalmanella tioga. 

Leiorhyll.chus sinuatum. 

Camarotrechia sappho. 

Delthyris mesicostalis. 

·Atrypa reticularis. 

Spirifer inarcyi. 

Sch uchertella che~ ungensis. . 

Chonetes setigera. 

Sphenotus sp. 

Palreoneilo sp. 

N ucula cf. corbuliformis. 

Orbiculoidea elmira. 

Leptodesma cf. agassizi. 

Modiomorpha neglecta. 

Pleurotomaria capillaria. 

Bellerophon cf. leda. 

Ma~rocheilina macrostoma. 

A viculopecten prin~eps. 

6. Ithaca.-One mile south of Ithaca on. the west side of Inlet Valley; elevation, approximately 410 feet above sea level. H. s. Williams, collector. Tropidoleptus zone of the Ithaca 

shale member. Fauna (Ith. IE, la): 

Rhipidomella vanuxemi. 

Leiorhynchus mesicostale. 

7. West Danby.-Section alongside hill and ravine west of village; lower part of the section; eleyation, 1,074 to 1,090 feet above sea leveL V. H. Barnett, collector, 1903, p. 56. Both 

above and below this zone the ordinary Portage fauna prevails, and about 150 feet above it 

the Dalmanella danbyi zone of the Chemung begins. Tropidoleptus zone No. 1 (Enfield shale 

member). Fauna (Ith. 3K, 1d, le, and lg): · ' 

Delthyris mesicostalis. 

Productella spin ulicosta. 

Chonetes sp. 

Ambocrelia umbonata. 

Pleurotomaria capillaria. -

Bellerophon brevilineatus. 

Palreoneilo brevis. 

Leiorhynchus mesicostale. 

Lingula spatulata: . 

Cf. Modiomorpha. 

Rhipidomella vanuxemi .. 

Camarotrechia cf. stephani. 

Paracardium doris. 

Cf. Goniatites discoideus. 

Cf. a small Cryptonella. 

Still higher, at 1,410 feet above sea level (Ith. 3K, lhhh) appears a trace of the Tropidoleptus 

zone No .. 2, which is listed in the table of geographic distribution of Spir~fer marcyi as No. 7a. 

(See p. 63.) -

8. Oayuta.-Hooker Creek, just below elbow west of Cayuta, near west edge of Ithaca 

quadrangle; 6 feet of soft sandstone and shale; elevation, approxUnately 1,444 feet above sea 

level. E. M. Kindle, collector, 1903, p. 30. Recurrent zone of doubtful horizon, probably 

No.2. Fauna (Ith. 15N, la): 

Rhipidomella vanuxemi. 

Leiorhynchus sinuatum_. I Productella cf. lachrymos_~· 

Orbiculoidea sp. 

9. ·spencer Lake ravine.-In deep gorge of stream running eastward and en1ptying into 

Spencer Lake; elevation, 1,175 to 1,185 feet above sea level. V. H. Barne'tt, collector, p. 51. 

Tropidoleptus zone No. 2 (Cayuta shale member). Fauna 2 (Wv. lA, ll): 

. Tropidoleptus carinatus. 

Cf. Rhipidomella. I 

Leiorhynchus multicosta . 

L. mesicostale. 

1 Ihavenotseen this fauna. Thelistofspecieswas made out in the field by E. M. Kindle, who says in his notes: "Hamilton fauna abundant.'' 

2 Twenty feet lower down in the section, in faunule W v. lA, ·lh, Phacops rana appears with Spirifer marcyi. The latter species appears in several 

beds above the typical recurrent fauna (ll), ranging up to Wv. lA, lv, which is about 100 feet higher than ll. See Spirifcr marcyi (p. 63). 
Palreoneilo bt·evis. 

Ambocroliu. umbonata. 

Spirifer cf. medialis. 

Schizophori~t stri~ttula. 

Productelht cf. hirsuta. 

Pleurotomaria sp. 

THE FAUNULES. 

Lingula cf. complanata (large). 

Cypricardella bellistriata. 

Grammysia subarcuata. 

Camarotrechia cf. sappho. 

Orbiculoidea sp. 

Modiomorpha sp. 

13 

10. Spencer Lake ravine.-Near top of ravine opening out to the east and running into 

Spencer Lake; elevation, 1,565 to 1,570 feet above sea level. V. I-I. Barnett, collector, p. 51. 

Tropidoleptus zone No. 3 (Cayuta s~1ale n1ember). Fauna (vVv. 1A, lvvv): 

'l'ropidoleptus carinatus. 

H.hipidomelht vanuxemi. 

Delthyris mesicostalis. 

Leiorhynchus sinuatum. 

Schizophoria striatula.. 

Dalmanella carinata. 

Schuchertella chemungensis. 

Crania leoni. 

Camarotrochia contracta. 

C. sappho. 

Atryp~t reticularis (coarse variety). 

Spirifer cf. medialis. 

S. cf. mttcronotus. 

Chonetes scitulus. 

Ambocrolia cf. gregaria. 

Athyris polita. 

Platyceras. 

Euomphalus cf. hecale. 

Bellerophon triliratus. · 

? Aulopora or Cladochonus. 

Paracyclas cf. tennis. 

Leptodesma cf. mortoni. 

Sphenotus sp. 

Pterinea cf. consimilis. 

Crenipecten cf. crenulatus. 

Productella cf. hirsuta (small). 

11. Spencer.-Section northwest of tl;1e Grove Hotel, Spencer, N. Y.; flrst outcrop· in mouth 

of ravine; elevation, 1,020 feet 'above sea leveL V. H. Barnett, collector, 1903, p. 56. Tropidoleptus zone No. 1 (Enfield shale 1nember). Fauna (Wv. 1B, 1b): 

Spirifer marcyi (high aJ·ea. and septum). 

S. pennatus var. 

Delthyris mesicostalis. 

Cyrtinu. hamiltonensis. 

Ambocrolia umbonata. 

Atrypa reticularis. 

Schizophoria striatula. 

Rhipidomella cf. v~tnuxemi. 

Crinoid stems. 

Loxonema sp. 

Productella sp. 

Conularia sp. 

Camarotrecbia cf. sappho. 

Tentaculites. 

12. Nobles Ilill.___:_Road running over the hill northward fr~n1 the valley of Cayuta Creek 

across Nobles I-Iill, by the roadside, near boundary 'between blocks Wv. 6B and Wv. 6A; hard 

coralline sandstone outcrops, above which the calcareous layers are leached out to form a brown 

"rotten stone;" elevation, 1,561 feet above ·sea level. C. L. Breger, collector, 1903, p. 29. 

Tropidoleptus zone No. 3 (Cayuta shale Inember). Fauna (Wv. 6B, 1a): 

Atrypa spinosa. 

Dalmanella tioga. 

Schizophoria striatula. 

Strophodenta (Douvillina) cayuta. 

Delthyris n~esicostalis. 

Productella laclu·ymosa. 

Ambocrolia umbonata gregat·ia. 

Schuchertella chemungensis. 

? Tt·opidoleptus carinatus (reported in the sandstone J)y 

C. L. Breger but no specimen collected). 

Pterinea cf. reverstt. 

G lossites lingualis. 

Loxonema tere bnt. 

Aviculopecten cf. cluplicatus. 

Pterinea cf. flabellum. 

Edmonclia phillipi. 

Edmondia cf. sp. 

Leptodesma liclms. 

Leptodesma sp. · 

N ucula umbonata. 

Tentaculites sp. 

Monotrypa sp. 

Rugose corals sp. 

Ceratopora chemungensis. 

Fenestella sp. 

Crinoid joints. 

13. Austin Ilill.-Sicle of roncl, running southwesterly from Swartwood near the sunll:nit· 

of the hill; outcrop of hard sandstone bands, approxilnately 3 feet in thickness, 2 or 3 inches 

of each consisting of a 1nass of fossils; elevation, 1,610 feet above sea level. Original-numbers 

• 
14 RECURRENT TROPIDOLEPTUS ZONES IN NEW YORK. 

7B, 1j, 1j2, 1j3• 

shale member). 

C. L .. Breger, collector, 1903, pp. 25-26. 

Fauna (Wv .. 7B, 1j): 

Tropidoleptus zone No. 3 (Cayuta 

Tropidoleptus carinatus. 

Rhipidomella vanuxemi. 

Delthyris mesicostalis. 

Cypricardella bellistriata. 

Schizophoria striatula. 

Dalmanella tioga. 

Craniella hamiltonire. 

Productella hirsuta. 

Atrypa spinosa. 

Camarotrechia cf. contracta. 

Macrodon chemungensis. 

Phthonia cylindrica. 

Platyostoma lineata. 

Monotrypella cf. furcata. 

. 11,.. Austin Hi.ZZ.-Southwest of S'wartwood, top of hill, outcrop at roadside; elevation, 1,610 

feet above sea level. C. L. Breger, collector, 1903, pp. 25-26. Tropidoleptus zone No. ·3 

(Cayuta shale member). Fauna (Wv. 7B, lj2): 

Rhipidomella vanuxemi. 

Spir .fer marcyi. 

Delt:6.yris mesicostalis. 

Cypricardella bellistri.ata. 

Dalmanella tioga. 

Schizophoria striatula. 

Camarotrechia cf. contracta. 

Chonetes scitulus. 

Craniella hamiltonire. 

Atrypa spinosa. 

Productella sp. lachrymosa. 

Mocliella pygmrea. 

Modiomorpha :mytiloides. 

Pleurotomaria capillaria. 

Platyostoma sp. 

Loxonema sp. 

Macrocheilina sp. 

Leiorhynchus cf. sinuatum. 

15. Austin Hill.-Near summit of hill southwest of Swartwood, alongside of road; elevation, 

1,610 feet above'sea level. C. L. Breger, collector, 1903, pp. 25-26. Tropidoleptus zone No.3 

(Cayuta shale member). Fauna (Wv. 7B, 1j3 ): 

Tropidoleptus carinatus. 

Rhipidomella vanuxemi. 

Spiri.fer marcyi. 

Delthyris mesicostalis. 

Cypricardella bellistriata. 

Schizophoria striatula. 

Chonetes scitulus. · 

Camarotrechia contracta. 

. Schuchertena chemungensis. 

Modiomorpha cf. concentrica. 

M. mytiloides. 

Phthonia cylindrica. 

Atrypa spinosa. 

Craniella hamiltonire. 

Leptodesma extenuatum. 

Lyriopecten suborbicularis. 

Actmopteria cf. boydi. 

Orbiculoidea sp. 

Euomphalus sp. 

Platyceras sp . 

Loxonema sp. 

I . 

16. Van ·Etten.-South of Van Etten station abo't1t half a mile, in strean1 running nearly 

north, east of main valley, in cliff on wes~ side of' stream at bridge; elevation, about 1;030 feet 

above sea level. H. S. Williams, collector, 1903, p. 9. Tropidoleptus zone No. 1· (Enfield 

shale member). Fauna 1· (Wv. 4D, 1a): 

Tropidoleptus carinatus. 

Spirifer :inarcyi. 

' Delthytis mesicostalis. 

Rhipidomella vanuxemi. 

Productella spinulicosta. 

Ambocrelia umLonata. 

Modiomorpha sp. 

Leptodesma sp. 

Lingula sp. • 

17. North Chemung.-About 200 yards north of forks of road, 1~ miles north of North 

Chemung; elevation, approximately 1,440 feet above sea level. E. :M. l{indle, collector, 1903, 

notebook No. 2, p. 33. Tropidoleptus zone No. 3 (Cayuta shale 1nember). Fauna (Wv . 

. 11H, 1a): 

Rhipidoniella vanuxemi. 

. Delthyris mesicostalis. 

Spirifer marcyi. · , 

Cypricardella belli.striata. 

Schizophoria striatula. 

Camarotrechia cf. stephani . 

Atrypa reticularis. · 

Dalmanella cf. carinata. 

1 This fauna comes from a typical exposure of the Tropidoleptus recurrent zone No.1. 

• 
THE FA UNULES . 15 

. lB. East Elmira.-Outcrop along road.side below house at corner of road abot1t 3 miles 

north of East Elmira, in about the middle of the section; thin-bedded sandstones weathering 

:iitto small angular blocks; elevation, about 1,500 feet above sea level. E. :M. Kindle, collector, 

1903, notebook No. 2, p. 7. Tropidoleptus zone No. 3 (Cayuta shale n1ember). Fauna (Wv. 

141, 1d): 

Tropidoleptus carinatus. · 

Rhipidomella vanuxemi. 

Cypricardella bellistriata. 

Spirifer marcyi. 

Macrocheilina macrostoma. 

Schuchertella chemungensis. 

Orthoceras sp. 

Camarotrechia cf. contracta. 

Productella hh·suta. 

19. Lockwood, east.-Section alongside of road running up the side of the hill east of 

Lockwood station; hard calcareous stratum about 6 inches thick in the sandstone; the lower 3 

inches is a "frrestone," which contains many fossils; elevation, about 1, 345 feet above sea level. 

C. L. Breger, collector, 1903, p. 42. Tropidoleptus zone No.3 (Cayuta shale member). Fauna 

(Wv. 3J, 1cl): 

T1·opidoleptus carinatus. 

Spirifer marcyi. 

Delthyris mesicostalis. 

Cypricardelln. bellistriata. 

Schizophoria striatula. 

Chonetes scitulus. 

Craniella hamiltonire. 

Schuchertella chemungensis. 

Productella lachrymosa. 

Platyceras cf. erectum. 

P. cf. conicum. 

Macrocheilina sp. 

Loxonema styliola. 

Bellerophon pelops. 

Platyostoma lineata. 

Pleurotomaria capillaria. 

Coleolus aciculum. 

Crinoid joints. 

20. Lockwood, west.-Hillside facing north, on south side of small west-east stream emptying 

into the main valley about a quarter of a mile south of Lockwood, on roadside; elevation, about 

1,389 feet above sea level. C. L. Breger, collector, 1903, p. 41. Tropidoleptus zone No. 3 

C9ayuta shale member). Fauna (Wv: 4J, 2a) =· .. 

Tropidoleptus carinatus. 

Spirifer marcy i. 

Delthyris mesicostalis. 

Cypricardella bellistriata. 

C. gregaria. · 

Cyrtina hamiltonensis. 

. Schuchertella chemungensis. 

Euomphalus hecale. 

Bellerophon cf. pelops. 

Schizophoria striatula. 

Atrypa spinosa. 

Camarotre~hia sp. 

Schizodus sp. 

Mui'chisonia sp. 

Pleurotomaria sp . 

21. Narrow Iiill.-ln the mid~t of cliffs facing Chemung River at the southern end of 

Narrow I-Iill,·at the southea.stern corner of block 9N, 1! miles northwest of Chemung village. 

The upper part of the cliffs is composed of thick sandstones with thin shaly partings; ,at the top 

of these is the calcareous sandstone band containing the fossils here listed; elevation, approximately 890 feet above sea level. C. L. Breger, collector, 1903, p. 58. Tropidoleptus zone 

No. 3 (Cayuta shale member). Fauna (Wv. 9N, 1aa): 

Tropidoleptus carinatus. 

Spirifer marcyi. 

Del thyris mesicostalis. 

Rhipidomella vanuxemi. 

. Cypricardella bellistriata. 

Chonetes scitulus. 

Dalmanella tioga. 

Camarotoochia sappho. 

Camarotrechia con tracta. 

Atrypa (aspera) spinosa. 

Limoptera macroptera. 

Glyptodesma sp. 

Pleurotomaria sp . 

Euomphalus sp. 

Bellerophon cf. pelops. 

Loxonema sp. 

22. Waverly.-Cliff along north side of railroad. tracks west of Waverly station, nearly 

opposite end of wagon bridge over Chemung River; band <:>f sandy shales 4 inches thick; elevation, approximately 850 feet above sea leve}. E. M. Kindle, collector, 1903, notebook No. 2, 
16 RECURRENT TROPIDOLEPTUS ZONES IN NEW. YORK· 

p. 4; and detailed section, V. H. Barnett, ~ollector, 1903, p. 37. Tropidoleptus zone No. 2 

(Cayuta shale 1nember). Fauna (Wv. 40, Ib): 

Tropidoleptus carinatus. 

·· Spirifer marcyi. 

Delthyris mesicostalis. 

Cypricardella bellistriata. 

Leiorhynchus siuuatum. 

Ambocrelia umbonata. 

Dalmanella cariuata. 

Atrypa reticularis. 

Camarotrechia cf. congregata. 

Loxonema sp. 

23. Waverly.-Cliff west of Waverly, north side of track, nearly opposite wagon bridge; 

Ig about 20 fe~t higher in the section than lb (faunule 22); and lh, 5 feet still higher; elevation, 

870 and 875 feet above sea level. V. H. Barnett, collector, 1903, p. 37. Tropidoleptus zone 

No. 2 (Cayuta shale member). Fauna (Wv. 40, Ig, Ih): 

Cypricardella bellistriata. 

Delthyris mesicostalis. 

Rhipidomelia vanuxemi. 

Productella lachrymosa. 

Camarotrechia cf. congregata: 

Ambocrelia umbonata. 

Orbiculoidea sp. 

Chonetes sp. 

Leiorhynchus cf. sinuatum. 

24. lVaverly.-Cliff west of Waverly, 10 feet ·higher than lh; ·shaly sandstone stratum lj7

• 

elevation approximately 885 feet above sea level. V. H. Barnett, collector, 1903, p. 37. 

Tropidoleptus zone No.2 (Cayuta shale member). Fauna 1 (Wv. 40, lj): 

Tropidoleptus carinatus. 

Rhipidomella vanuxemi. 

Spirifer marcyi. 

Delthyris mesicostalis. 

Cypricardella bellistriata. 

Ambocrelia umbonata. 

Schizophoria striatula. 

Camarotrechia cf. congregata. 

C. sappho. 

Productella lachrymosa. 

Modiomorpha sp. 

Loxonema sp. 

Pleurotomaria sp. 

Be~lerophon sp. 

25. Glory !/ill, Waverly.-Quarry on the southeast slope of Glory Hill, about 2 miles west 

of Waverly, near the top of the quarry; calcareous band of sandstone; filled with fossils; elevation, 1,165 to 1,170 feet above sea level. (Original label "b 40.") V. H. Barnett, collector, 

1903, p. 38. ·Tropidoleptus zo.ne No. 3 (Cayuta shale member). Fauna 2 (Wv. 40, 2nn): 

Tropidoleptus carinatus. 

Delthyris mesicostalis. 

Spirifer marcyi. 

Schizophoria striatula. 

Chonetes ~etigerus. 

Pleurotoinaria cf. capillaria. 

Loxonema sp. (smalJ). 

Leptodesma sp. 

26. Mount Pleasant.-Ravine south of Etna, r.unning down northern face of Mount Pleasant; 

thin-bedded sandy shales containing the recurrent fauna; elevation, 1,405 to 1,410 feet above 

sea level. V. H. Barnett, collector, 1903, p. 8. Tropidoleptus zone No. 1 (Enfield shale 

member). Fauna (Dr. 9B, Icc): 

Rhipidomella vanuxemi. 

Spirifer marcyi. 

S. cf. pennatus. 

Cyrtina hamiltonensis. 

Lingula sp. 

Chonetes scitulus. 

Schizophoria striatula. 

Camarotrechia cf. eximia. 

Atrypa reticularis. 

Ambocrelia umbonata. 

A viculopecten cf. suborbicularis. 

Pleurotomaria' sp. 

Euomphalus sp. 

27-29. Dryden Lalce.-Upper part of the small stream groove running down the eastern 

face of the high hills to the west of Dryden Lake, northeast corner of block 3D; outcrops containing traces of the recurrent fauna .. Elevation about 1,685 to 1,690 feet above sea level (lj); 

10 feet higher (ll); and 1,723 feet (lo). V. H. Barnett, collector, 1903. 

1 Five feet still higher in the section Spirifer fimbriatus was found with Dalmanella carinata, Spirifer marcyi, and other species. 

2 Ill a loose fragment in bed of quarry, of the same character of rock and containing Tropidoleptus, I found a fragment of a fish bone. The 

bone fragment is over half an inch thick, 2 inches by 1! inches across, and is evidently part of a·bone which was originally of large dimensions.· 
THE FAUNULES. 17 

27. Tropidoleptus zone No. 1 (Enfield shale member). Fauna (Dr. 3D, 1j): 

Tropidoleptus carinatus. 

Rhipidomella vanuxemi. I 

Chonetes cf. scitulus. 

Ambocrelia umbonata. 

28. Tropidoleptus zone No. 1 (Enfield shale member). Fauna (Dr. 3D, ll): 

, Tropidoleptus carinatus. 

Rhipidomella vanuxemi. 

Delthyris mesicostalis. 

Proquctella spinulicosta. 

Chonetes cf. scitulus. · · 

Camarotrechia cf. cximia. 

Ambocrelia umbonata. 

Grammysia sp. 

Leiopteria sp. 

1 A viculopecten sp. 

29. Tropidoleptus zone No. 1 (Enfield shale Inember). Fauna (Dr. 3D, 1o): 

Tropidoleptus carinatus. 

Rhipidomella vanuxemi. 

Delthyris mesicostalis. 

Spirifer marcyi. 

Productella spinulicosta. 

Atrypa reticularis. 

Palreoneilo cf. brevis. 

A viculopecten sp. 

Pleurotomaria sp. 

30-31. East Danby.-A.bout 1! miles west of the Caroline junction of the Lehigh Valley and 

Delaware, Lackawanna & Western railroads, in the upper part of the small stream cutting 

easterly down the hillside; outcrop, 1b, at elevation of 1,475 to 1,485 feet above sea level; and 

1d, at elevation of 1,495 to 1,505 feet. C. L. Breger, collector. Tropidoleptus zone No. ·1 

(Enfield ::,hale mmnber). Fauna (Dr. JJII, ib, 1d): 

Tropidoleptus carinatus. 

Rhipidomella vanuxemi. 

Delthyris mesicostalis. 

Spirifer fimbriatus. 

Phacops rana. 

Camarotrechia. sp; 

Leiorhynchus mesicostale. 

Leptodesma sp. 

Modiomorpha sp. 

Schuchertella chemungensis. 

Productella sp .. 

Ambocrelia umbonata. 

Palreoneilo sp. cf. brevis. 

32. Bald Mountain.-Middle summit, upper part of section running up the stream valley 

which cuts the east side of the hill and empties into the valley about 3 miles south of Slaterville, near summit of hill; elevation, 1,778 feet above sea level. V. H. Barnett, collector, 

1903, p. 15. Tropidoleptus zone No. 2 (Cayuta shale member). Fauna (Dr. 81, 1n, not Dr. 

71, 1 n, as label indicates): 

Tropidoleptus carinatus. Schizophoria striatula. 

Rhipidomella vanuxemi. Dalmanella tioga. 

Delthyris mesicostalis. Camarotrechia sappho. 

Spirifer marcyi. Atrypa spinosa. 

Cypricardella bellistriata. Ambocrelia umbonata. 

Orbiculoidea sp. Cf. Lyriopecten. 

Linl?ula cf. complanata. Modiomorpha sp. 

82a. Bald Hill, Oaroline.-Bed of road running .north and south, in the southeast.quarter 

of block Dr. 81; outcrop 1 of 7 to 8 feet of flaggy sandstones, in the lower part of which the Tropidoleptus fauna appears; elevation, 1,760 to·1,767 feet above sea. C. L. Breger, collector, 1905, 

p. 84. Tropidoleptus zone No. 2 (Enfield shale member). Fauna (Dr. 81, 2a): 

Tropidoleptus· carinatus. 

Delthyris mesicostalis. 

Rhipidomella vanuxemi. 

Spirifer marcyi. 

Dalmanella tioga. 

Ambocoolia umbonata. 

Productella cf. spinulicosta 

P. cf. hirsuta. 

Schizophoria striatula. 

Chonetes scitulus. 

Lingula sp. 

Orbiculoidea. 

Leiorhynchus multicosta. 

Camarotrechia cf. eximia. 

Cladochonus. 

'Platyceras sp. · 

Pleurotomaria. 

Modiomorpha. 

Grammysia: 

Cf. A viculopecten. 

1 'ehls Is probably tho samo outcrop discovered by'V. H. Barnett (Dr. il, ln). For the purposes of this paper the two will be considered 

under tho one sample No. 32. 

67437°-No. 79-13-2 
/ 

18 RECURRENT TROPIDOLEPTUS ZONES IN NEW YORK. 

33. "White Ohurch.-About h~lfway up the stream valley yutting the hillside north of 

White Church; shales and shaly thin-bedded sandstones outcropping below and above the 

second bridge; elevation, 1,298 to 1,314 feet above sea level. C. L. Breger, collector, 1905, 

p. 81. Tropidoleptus zone No~ 1 (Enfield shale member). Fauna (Dr. 81, lc): 

Tropidoleptus carinatus. 

Rhipidomella vanuxemi. 

Spirifer marcyi. 

Delthyris. mesicostalis. 

Phacops rana. 

Coleolus aciculum. 

Pleurotomaria capillaria. 

Amboccelia umbonata. 

Orbiculoidea. 

Leiorhynchus cf. multicosta. 

Camarotcechia sp. 

Chonetes. 

Productella spinulicosta. 

Schuchertella chemungensis. 

Leptodesma sp. 

Small starfish. 

Grammysia sp. 

A viculopecten sp. 

Palreoneilo. 

P. cf. plana. 

· Bellerophon. 

Loxonema (large sp.). 

Of. Cypricardinia sp. 

Modiomorpha sp. 

M. subalata. 

Of. Platyceras sp. 

34-. Deputron Oree~.--Deputron Creek, runni~g down the eastern face of the hills,oppositc 

Caroline Depot, near the soi1thern border of block 11H; several outcrops (field labels Dr. 111, 

\ lb; Dr. 111, lc) of a coarse blocky sandstone and shales containing traces of the recurrent 

fauna; elevation, 1,375 to 1,395 feet above sea level. C. L. Breger, collector, 1905, p. 89., 

Tropidoleptus zone No. 1 (Enfield shale member). Fauna (Dr. 121, 4b): 

Tropidoleptus carinatus. 

Rhipidomella vanuxemi. 

Spirifer marcyi. 

Delthyris mesicostalis. 

Amboccelia umbonata. 

Schizophoria striatula. 

Productella cf. lachrymosa stigmata. 

P. cf. spinulicosta. 

Camarotcechia cf. contracta. 

Chonetes scitulus. 

Orbiculoidea. · 

Cyrtina hamiltouensi~. 

Atrypa reticularis. 

Spirifer cf. pennatus p~sterus. 

A viculopecten cf. fasciculatus. 

Cladochonus sp. 

Palreoneilo plana. 

P. brevis. 

Crinoid stems. 

Lingula sp. 

Tentaculites sp. 

Grammysia sp. 

l\focliomorpha SP,. 

$5-36. White Ohurch.~San1e ~ection as faunule 33. Collected by V. I-I. Barnett, 1903, 

notebook, p. 25; elevation 1,273 to 1,288 feet (1p) and 1,288 to 1,298 (lg) above sea level 

(reported under field label Dr. 81, lc): 

35. Tropidoleptus zone No. 1 (Enfield shale member). Fauna (Dr. 9J, .tp): 

Tropidoleptus carinatus. 

Rhipidomella vanuxemi. 

Chonetes setigera-scitulus. 

Productella cf. spinulicosta. 

Qamarotcechia cf. eximia. 

Leiorhynchus cf. mesicostale. 

Amboccelia umbonata. 

Modiomorpha sp. · 

36. Tropidoleptus zone No. 1 (Enfield shale member). Fauna (Dr. 9J, lq): 

Tropidoleptus carinatus. 

Rhipidomella vanuxemi. 

Productella cf. spinulicosta. I 

Camaro~cechia. cf. ex~ia. 

Delthyns mes1costahs. 

Spirifer marcyi. 

The fauna containing Spirifer marcyi (seep. 63, under syn1bol Dr. IlK, 1 E.M.I{.) is in an 

outcrop on the other side of the valley on the side of Eastman Hill, and belongs to the san1e zone. 

It may be numbered 36a. 

37-39. North Oandor.-Section begins at the first outcrop of sandy shale in a small ·stream 

on the north side of wagon road, situated in the southwest corner of ·block 9A, at a1i elevation of 

about 1,040 feet above sea level and 'followsyp the hill toward the north. The zones from which 

the recurrent fauna come are lh at 1,075 feet, ll at 1,095 to 1,102 feet, and lm at 1,102 to 1,109 

feet above sea level. V. H. Barnett, collector, 1903, notebook No. 2, p. 64. 
THE FAUNULES. 19 

:37. Tropidoleptus zone No. I (Enfield shale mmuber). Fnuna (Ow. 9A, 1h): 

Rhipidomella vanuxemi. 

Del t;hyris mesicostalis. 

Ambocrelia umbonata. I 

Camarotrechia sappho. 

Leptodesma sp. 

Modiomorpha sp. 

38. Tropidoleptus zone No. 1 (Enfield shale n1ember). Fauna (Ow. 9A 1Z): 

Tropidoleptus carinatus. 

Ithipidomella vanuxemi. 

Delthyris me~icostalis. 

Spirifer marcyi. 

Product:el1a spin u licosta. 

Chonetes. 

Camarotrechia cf. sappho. 

Bellerophon cf. lncisus. 

Cf. Nucula sp. 

Leptodesma ~p. 

Pleurotomaria sp. 

39. Tropidoleptus zone No. I (Enfield shale n1ember). Fauna (Ow. 9A, 1m): 

Tropidoleptus carinatus. 

Rhipidomella vanuxemi. 

Delthyris mesicostaJis. 

Spirifer marcyi. · 

Camarotrechia sappho. 

Cyrtina hami.ltonensis. 

Schizodus. 

Goniophora sp. 

Pleurotomaria. 

Loxonema sp. 

1,.0. Spencer, east.-:Mouth of sn1allravine one-half mile east of Spencer, outcrop of shaly 

sandstones containing the recurrent fauna; elevation, I,025 feet above sea level. E. M. Kindle, 

collector, I904, notebo9k No.2, p. I7. Tropidoleptus zone No. l(Enfield shale member). Fauna 

(Ow. I4C, I): 

TrQPidoleptus carinatus. 

Spirifer marcyi. 

Delthyris mesicostalis. I 

Productella cf. spinulicosta. 

Pleurotomaria sp. · 

Cladochonus. 

1,.1. Owego, no'rth.-Quarry north side of Owego on Cemetery Hill; n1iddle of quarry fnce; 

elevation, slightly more than I,OOO feet abov·e sea level (I,OIO to I,020 feet). V. H. Barnett, collector, I904, p. 34. Tropidoleptus zone No. 2 (Cayuta shale n1ember). Fauna (Ow. II, Id): 

Tropidoleptus carinatut~. 

Spirifet· marcyi. 

Cypricardella bellistriata. 

Modiomorpha sp. 

Ambocrelia umbonata. 

Camarotrechia sp. cf. congregata. 

Productella cf. lachrymosa. 

Loxonema sp. 

Schizodus. 

Holopea macro~toma. 

A faunule (lj) about 10 feet above No. 41 co~1ta.ins, in addition, Rhipidomella vanuxemi. 

Lower down in the quarry, at an altitude of 980 feet above sea level a specimen of S'fiirifer 

disiunctus was found, showing definitely the position of the zone in the section. This is the 

original locality of the Tropidoleptus zone described later as the recurrent Tropidoleptus 

fauna from Cemetery Hill, Owego, Tioga County. 1 

1,.2. Owego, north.-Qum·ry in northern part of Owego on the southerly slope of Cemetery 

Hill. Same locality as faunule 41. Cornell University :Museum, L. Reinecke, collector, I904, 

notebook, pp. 60, 61. Tropidoleptus zone No. 2 (Cayuta shale n1e1uber). Fauna (Ow. II, Id): 

Tropidoleptus ca1:inatus. 

Spirifer marcyi. 

Delthyris mesicostalis. 

Cypricardella bellistriata. 

Phacops rana. 

Macrodon hamiltonire. 

Productella cf. lachrymosa. 

Of. Euthydesma subtextilis. 

Camarotrechia sappho. 

Modiomorpha cf. macilenta. 

1,.3. Osborn.-Section begins in the first outcrops of rock in the strea~u valley east of Osborn, 

and rups up into the hill to the east. The recurrent fauna appears on the west side of block 

1 Williams, H. S., }~ossil faunas and their use in cOrrelating geological formations: Am. Jour. Sci., 4th ser., vol. 13, 1902, p. 429. 
20 RECURRENT TROPIDOLEPTUS ZONES IN NE''r YORK. 

120; elevation, 1,112 to 1,114 .feet above sea level. V. H. Barnett, collector, 1904, pp. 68, 69. 

Tropidoleptus zone No. 3 (Cayuta shale member). Fauna (Ow. 120, ~p): 

Tropidoleptus carinatus~ Bellerophon sp. 

Delthyris mesicostalis. Cf. Leda sp. 

Spirifer cf. marcyi. · Amb'ocmlia umbonata. 

Cypricardella bellistriata. Camarotrechia cf. contracts. 

Leiopteria cf. mitchelli. C. cf. congr.egata. 

Chonetes scitulus. Productella cf. lachrymo~. 

Leptodesma cf. lichas. Platyceras. 

Palreoneilo cf. plana. Pleurotoniaria. 

Q. 44. Blodgett Mills.-Section jn first creek south of Blodgett :Mills running into the Tiough-· 

nioga from the west; elevation, between 1,2~6 and 1,300 feet above sea level. L. Rein.ecke, 

collector, 1904, pp. 53, 54. Tropidoleptus zone in the Ithaca shale member. Fauna (Ct. 

8L; 1q): 

Tropidoleptus carinatus. Camarotmchia eximia. 

Cypricarde1la bellistriata. Leiorhynchus cf. mesicostale. 

Spirifer mesistrialis. Leiopteria sayi. 

S. pennatus posterus. L. cf. greeni. 

Chonetes scitulus. Goniophora rugosa.· 

C. deflectus. Tentaculites sp. 

45. Blodgett Mills.-Massive·light-gray sandstones, resting on the sandstones described in 

faunule 44; elevation, approximately 1,300 to 1,315 feet above sea level. L. Reinecke, collector, 

1904, p. 53. Tropidoleptus zone in the Ithaca shale member. Fauna (Ct. SL, 1r): 

Tropidoleptus carinatus. Spirifer pennatus posterus. 

Cypricardella bellistriata. Chonetes scitulus. 

Spirifer mesistrialis. Palreoneilo sp. 

S. pennatus. Le~opteria cf. rafinesqui. 

46. Messengerville.-Briclge over Tioughnioga River; elevation, about 1,045 feet above sea 

level. V. H. Barnett, collector, 1904, p. 7. Tropidoleptus zone in the Ithaca shale member. 

Fauna (Hd. 5A, If) : 

Tropidoleptus carinatus. Chonetes. 

Spirifer mesistrialis. Grammysia. 

Delthyris cf. consobrinus. . Tentaculites. 

Cyrtina ~amiltonensis. Leptodesma. 

Productella sp. spinulicosta. Cypricardella bellistriata (small). 

47. Messengerville.-Section beginning at Hd. 5A, 1a, just below the bridge over Tioughnioga River east of Delaware, Lackawanna & Western tracks, and running upward through, 

East Virgil and Messengerville; elevation (baro~etric), 1,048 feet above sea level. L. Reinecke, 

collector,, 1904, p. 50. Tropidoleptus zone i:t;1 the Ithaca shale n1ember. Fauna (Hd. 5A,. 1a): 

Tropidoleptus carinatus. 

Cypri card ella bell istria ta. 

Spirifer mesistrialis. 

S. pennatus posterus (small). 

Leptodesma small sp. 

M<?diomorpha cf. concentrica. 

Grammysia elliptica. 

Palreoneilo constricta. 

N ucula corbuliformis. 

Tentaculites. 

· Orthoceras cf. bebryx . 

. Crinoid joints. 

48. Lapeer.-Summit of road running northwest from Lapeer; elevation, approximately 

1,800 feet above sea level. E. ~I. Kindle, collector, 1904, p. 53. Tropidoleptus zone No. 2 ~' 

in Chemung formation. Fauna (Hd. 8C, 2a): 

Tropidoleptus carinatus. 

Of. Delthyris mesicostalis. 

Camarotmchia sp. · 

L~ptodesma. 

Creni pecten. 

Productella sp; 

Ambocmlia umbonata. 

This fauna is within the zone which on lithologic evidence has been mapped as Chemung, 

but on account of the scantiness of the fossils discovered in the neighborhood its exact position 

• 
'. 

THE FA UNULES. .21 

in the series is not certain. For purposes of djscussion I class it with the· Tropidoleptus zone 

No. 2 (?). 

49-53. llmford .Jl!iZZs.-Section begins at mouth of gorge opening into the enst brnnch of 

Owego Creelr 1! miles southeast of IIarford Mills; outcrops containing Tropidoleptus are at 

elevntions of 1,420 (1k), 1,470 (lq), 1,475 (1r), 1,485 to 1,495· (ls), nnd 1,506 to 1,530 (1v) feet 

above sea. L. Reinecke, collector, 1904, p. 27. 

49. Tropidoleptus zone No. 1 (Enfield shnle n1en1ber). Fauna (l-Id. 1GG, lk): 

Cf. Tropidoleptus carinatus. 

Camarotoochia cf. sa.ppho. 

Delthyris mesicostalis. 

50. Tropjdoleptus zone No. 1 (Enfield shale n1ember). Fnuna (l-Id. 13G, lq): 

TropidolepttiS carinatus. 

Delthyris mesicostalis. 

Schuchertella chemungensis. 

Chonetes scitulus. 

Ambocoolia umbonata. 

Camarotoochia cf. &'l.ppho. 

Leptodesma cf. lichas. 

L. cf. potens. 

51. Tropidoleptus zone No. 1 (Enf1eld shale member). Fauna (Hd. 13G, 1r): 

Camarotoochia cf. sappho. 

Cf. Delthyris mesicostalis. 

Cf. Tropidoleptus carinatus. 

52. Tropidoleptus zone ·No. 1 (Enfield shale 1nmnber). Fauna (H(l: 13G, Is): 

Tropidoleptus carimttus. 

Rhipidomella vanuxemi. 

DeltJ1yris mesicostn.li's. 

Camarotoochia cf. contracta. 

4trypa reticularis (large). 

l\fodiomorpha mytiloides. 

Leiopteria cf. rafinesqui. 

Limoptera macroptera (small). 

Crinoid joints. 

53. Tropidoleptus zone No. 1 (Enfield shale member). Fauna1 (Hd. 13G, lv): 

Tropidoleptus carinatus. Cmniella hamiltonire. 

Delthyris mesicostalis. Leptodesma cf. liclms. 

Cypricardella bellistriata. · L. cf. creon. 

Rhipidomella vanuxemi. ~eiopteria cf. conmdi. 

Spirifer marcyi. L. cf. rafinesqui. 

Cttma.rotoochia sappho. Glyptodesm<u erectum. 

Chonetes scitulus. A viculopecten cf. princeps. 

Spirifer cf. pennatus. Gmmmysia subarcun.ta. 

54. Oente·r Lisle.-East-west road, about 2 n1iles west of Center Lisle, near the western 

boundary line of Broome· County; 40 to 50 feet of drab sandstone; elevation, 1,410 feet above 

sen. level. E. :M. Kindle, coll'ector, 1904, p. 61. Tropidoleptus zone No. 1 (Enfield shale 

1nember). Faunn. (l-Id. 7I, la): · 

Tropidoleptus carinatus. 

Hhipidomella vnnuxemi. I Delthyris mesicostalis. 

Ambocoolia umbonata. 

55. Lisle.-Section up hillside sloping northward along north-south road in middle of 

block 2J. Elevation of Tropidoleptus zone, about 1,350 feet above sea level. L. Reinecke, 

collector, 1904, pp. 55 and 56. Also E. M. Kindle, collector, 1904, p. 92. Tropidoleptus zone 

No. 1 (Enfield shale men1ber). Faunn 2 (l-Id. 2J, le): 

Rhipidomella vanuxemi. 

Tropidoleptus carinatus. 

Cypricardella bellistriata. 

Camarotoochia cf. eximia. 

C. cf. &'tppho. 

Chonetes sp. 

Cyrtina hamiltonensis. 

Modiomorpha' sp. 

? Fish plate. 

1 The field lahol for this fauna appears to he lid. 13G, lv; from the fullness of the fauna it is thought possible that the letter r hac; been mistaken for v and that 51 and 53 should be transposed. · 

~ A fow foot higher Spirifcr marcyi and Rhipidomella occur at 1,305 to 1,31G feet. In the same fauna is seen Spirijcr marc¥i with a rudimentary 

syrinx and Rllipidomclla vanuxcmi. 

., 

\ 
22 RECURRENT TROPIDODEPTUS ZONES IN NEW YORK. 

56. Berkshire.-Ravine west of village of Berkshrre; 15 feet of grayish-blue sandy shale; 

elevation, 1,165 to 1,170 feet above sea leve_l. V. H. Barnett, collector, 1904, notebook No. 2, 

p. 19. Tropidoleptus zone No. 1 (Enfield shale member). Fauna (Hd. 12L, lZ): 

Tropidoleptus carinatus. 

Rhipidomella vanuxemi. 

Spirifer cf. marcyi. 

Delthyris mesicostalis. 

Productella cf. spinulicosta. 

. Lingula complanata. · 

Ambocrelia umbonata. 

Chonetes. 

Pleurotomaria. 

Modiomorpha. 

Camarotrechia cf. eximia . 

57. Maine.-Section begins in the foot of the ravine opening into Nanticoke Creek_east 

and a little south of the center of village of Maine; elevation, 1,041 to 1,055 feet above sea level. 

L. Reinecke, collector, 1904, p. 57. Tropidoleptus zone No. 1 (Enfield shale member). Fauna 

(Ap. 4D, lg): 

Tropidoleptus carinatus. 

Delthyris mesicostalis. 

Spirifer cf. pennatus. 

Camarotrechia cf. sappho. 

Ambocrelia gregaria. 

Leptodesma potens. 

Edmondia cf. philippi. 

58. Oakley Oorners.-Road running west from Oakley Corners, eastern side of block liE; 

about 30 feet of shaly sandstones containing Tropidoleptus; elevation, 1,500 -feet above sea level. · 

E. M. Kindle, collector, 1904, p. 27 .. Tropidoleptus ~one No.3 (Cayuta shale member). Fauna 

(Ap. liE, la): 

Tropidoleptus carinatus. 

Spir~fer fimbriatus. 

S. marcyi. 

Rhipidomella vanuxemi. 

Delthyris mesicostalis. 

Dalmanella tioga. 

Ambocrelia umbonata. 

Cypricardella bellistriata. 

Platyceras sp. 

Crinoid stems. 

59. Whittemore.-Summit. of hill marked 1514 on Apalachin topographic sheet, in the 

northern part of block 8G, in t_he road opposite a house; 2 feet of shaly sandstones containing 

Tropidoleptus; elevation, 1,514 feet above sea level. E. l\1. J{indle, collector, p. 27 .. Tropidoleptus zone No. 3 (Cayuta shale Inember). Fauna (Ap·. 8G, 3a): 

Tropidoleptus carinatus. 

Spirifer marcyi. 

Rhipidomella vanuxemi. 

Delthyris mesicostalis. 

Cypricardella cf. bellistriata. 

Dalmanella ~P· 

Chonetes sp. 

Productella. 

Ambocrelia umbonata. 

Schuchertella chemungens~. 

Schizophoria striatula. 

Camarotrechia. 

Platyceras. 

60. Apalachin.-Road running south from fiiawatha Island up the,hill, in the north edge 

of block 13L; a calcareous band 6 inches thick, containing Tropidoleptus; elevation, 1,180 feet 

above sea level. E. l\1. Kindle, collector, 1904, p. 91. Tropidoleptus zone No. 2, Chemung 

formation. Fauna (Ap. 13L, 1): 

Tropidoleptus carinatus. 

Cf. Delthyris mesicostalis. 

Spirifer marcyi. 

Ambocrelia umbonata. 

Chonetes. 

Camarotrechia cf. eximia. 

? Schiwphoria striatula. 

Crinoid stem. 

The failure to discover in this general area fossils that mark the boundaries of the range of 

the Chemung fauna leaves doubt as to _the actual horizon of this fauna. It is clearly above the 

base of the Chemung a11d there are recurrent faunas at a level stratigraphically higher. I have 

therefore listed it as probably belonging in Tropidoleptus zone No. 2. 

61. Tracy Oreek.-Section along road ascending hill west of Tracy Creek village. Hard 

calcM'eous sandstone weathering to brown i·otten stone containing Tropidoleptus; elevation, 
STRATIGRAPHIC POSITIONS. 23 

1.,300 feet above sea level. V. H. B~rnett, collector, 1904, p. 26. Tropidoleptus zone No. 3 

(Cayuta shale· member). Faunn (Ap. 5N, 1c): 

Tropidoleptus carinatus (rare). 

Delthyris mesicostalis. rJl 

Spirifer disjunctus. ~ 

Productella. ~ 

Macrocheilina macrostoma. 

Pleu rotonmria (large). 

Loxonema (large). 

Bellerophon macra. 

Pterinea chemungensis 

Edmonclia sp. 

Crinoid stems. 

62. Tracy Oreek.-San1e section as faunule 

61, but higher; calcn,reous sandstones with Tropi- · 

doleptus; elevation, about 1,402 feet above sea 

level. V. I-I. Barnett, collector, 1904, p. 27. Tropidoleptus zone No. 3 (Cayu tn shale member). 

Fauna (Ap. 6N, lo): 

Tropidoleptus carinatus. 

Spirifer cf. pennatus. 

Chonetes. 

63. Tracy Oreelc, southwest._-Northwestcorner 

of block 60, 200 to 300 yards southwest of forks 

of road. A loose block of bla~kish ferruginous 

1nass holding numerous specimens of Tropidoleptus, with flat pebble conglomerate; elevation, 

1,600 feet ebove sea level. E. ~1. Kindle, collector, 1904, p. 85. Tropidoleptus zone. No. 3 

(Cnyutn, shale Inember). Fauna (Ap. 60, 4): 

Tropidoleptus carinatus. 

Bellerophon. 

Spirifer fragme.nts. 

Chonetes sp. 

TIIJ!J UECUUUENT ZONES. 

STRATIGRAPHIC POSITIONS. 

The several recurrent faunules here considered 

were taken from certain· definite positions in the 

strntigraphic sequence, not lower than the Ithaca 

1nember of the Portage formation and not higher 

than the top of the Cayut~ Inember of the Chennmg formation. Each individuaJ faunule is 

limited in range to a few feet and in many places 

·to a few inches of thickness of strata; the composition of the faunas both below and above in many <.!) z zQ sections shows a strong contrast to the specific => ~ 

~::?! cOin position of the particulnr faunule listed. . On J: a: uo tnbulating the sections the individual faunules ~... 

·hnve been found to occur in four definite zones situated as foll<:nvs: 

1. The Tropidoleptus zone of the Ithaca shale member. In the lower part of the Portage 

fonnation not over 50 feet n.bove the base of the Ithn.ca mmnber.1 · . 

2. The 'rropidoleptus zone No. 1. In the upper part of the Portage, within the uppermost 

200 feet of the Enfield shale Inmnber. Represented. there by severn! successive individual 
24 RECURRE~T TROPIDOLEPTUS ZONES IN NEW YORK. 

faunules, ranging through nearly 100 vertic~! feet in some of the 1nH)re eastern sections but 

restricted to narrower limits in the more western sections. 

3. The Tropidoleptus zone No. 2. In the lower third of the Cayuta shale member of the 

Chemung formation, near the horizon where the Chemung fauna has first reached its full 

Feet 

1100 

1000 

900-

800-

700-

600 

500-

I 

Taghanic 

Ravine 

Genesee 

shale 

135' 

~, 

\ 

\ 

\ 

400 -t-+- ?'' ----;fz 3 I Tully 0-

limestone ~!;{ . . 15' i~ 

~e 

rr rrr 

Glenwood Fall Creek Ith. 3A Dr. 15C 

Feet 

1080 Enfield shale member 

' 

\ 

z 

0 

i= 

~j 0: 

0 

.... 

ILl 

(.!) 

<( 

1-

0: 

0 

a.. 

?f' 

'sandstone 

lentil exposed in Cascadilla 

Creek 

(=Mesistriai!.s 

I zone) .. 

I\ 

\ 

\ 

\ 

I ~Reticularia \ 

\ ... \ 

\ 

\ 

\ 

\ { 

lrevis 

zone 

Genesee 

shale 

~ \ 

5 \ OJ ' \ 

~ \ i \ ..::: \ 

E 

..c 

~ en 

\ "14 N" 1 rH.S. w. 

Ithaca 

shale of. H.S.Williams 

Reticula ria 

lrevis 

zone 

H a 

--

FIGURE ~.-Sections at Taghanic Ravine (I), Glenwood (II), and Fall Creek (III). 

GEOLOGIC SECTIONS. 

expansion. 

4. The Tropidoleptus zone 

No.3. At the top of the Cayuta 

member of the Chemung; at the 

dose of the fullest expansion in 

numbers of specimens and dominance of the ,more characteristic Chemung species. Above 

this zone Spirifer disjunctus, 

which is characte.ristic of the 

Chemung, ceases to appear in 

the sections of this region, although n1any other characteristic Chemung species continue. 

This change in fauna is the 

chief ground for distinguishing the upper (Wells burg sandstone) member from the lower 

(Cayuta shale) member of the 

Chemung. 

The relation of the recurrent zones to 'the several formations and members recognized 

in the area may be summed 

up as below. These relations 

are also graphically ·shown in 

figure 2. · 

Chemung formation: . 

Wells burg sandstone member. 

Cayuta shale memberTropidoleptus zone No.3. 

Tropidoleptus zone No.2. 

Dalmanella danbyi zone. 

Portage formation: 

Enfield shale memberTropidoleptus zone No. 1. 

Ithaca shale memberMesistrialis zone. 

Tropidoleptus zone of Ithaca member. · 

Sherburne flagstone memberReticularia loovis zone 1 at 

top. 

Genesee shale. 

Tully limestone. 

Hamilton formation. 

Stratigraphically, the position of the recurrent zones is determined by reference to the bounr daries of the geologic formation in which the faunules indicating· them occur. In few pla.ces, 

however, were the faunules found in so direct a relation to the stratigraphic boundaries that 

I , 1 Shown in Glenwood section, fig. 3. 
GEOLOGIC SECTIONS. 25 

their precise distanc9 above or below the terminal beds could be accurately measured. In most 

places the limiting beds were at a distance and it was necessary to establish their stratigraphic 

position by estimating the amount and direction of dip of the stratum to the nearest. point where 

the relations to the boundaries could be observed. In a few places, however, the relation between 

the recurrent zones and some one of the formation boundari~s was shown by nearly continuous sections. 

IV 

Brookton 

Feet Dr. SH nnd 9H 

1500 

SH. 2b 

)1 SH. 2n 

1400 :S 

§-

~ The dip fror.1 Dr. SG, le to Dr. SH, 2b.is ·npproximntely' 

200 feet, in- · crensing the distance ver- 1300 ticnl between the top of the lthncn member to the Tropidoleptus zone 

~~X~~~~); GOO feet 

1200 

Ling-ula 

zone 

9H, 2n 

llOO 

Dr. SG, lc 

1000 

Ithaca shale 

member 

of Portage 

.formation . 

900 

F10. 4. 

Feet 

1800 

1700 

1000 

1500 

1400-' 

'130Q' 

~~~ 

1 

,V 

White 

Church 

Dr. 91 

Dr. 9l.ls 

lp nnd lq 

Tropidoleptu11 zone No.1 

FIG. 5. 

VI 

Bald Hill, 

Caroline 

Dr. 91 

In 

Tropidoleptus zone. No. Z 

FIGURE 4.-Section at Brookton (IV). 

1700 

1600 

West Danby lth. 3K 

FIGURE 5.-Scctions at White Church (V) and Bald Hill, Caroline (IV). 

FIGURE G.-Section at West Danby (VII). . 

FIGURE 7.-Section at Spencer Lake ravine (VIII). 

vm 

Spencer Lake Ravine 

.Wv.lA 

Fee t 

170. 0 

1600 

1500 

1400 

1300 

1200 

,- 1100 

1060 

luuu 

'1('' 

If Tl·opidolep-. 

tus zone No.3 

11 4 

Tropidoleptus zone No.~ 

Railroad 

level 

FIG. 7. 

For illustrating the relations the following 27 sections (see figs. 3.:...14) have been selected: 

( Taghanic Ravine. VI. Bald Hill (Caroline), Dr. 71 and Dr. 91. 

II. Glenwood, Ith. 3A. VII. West Danby, Ith. 3K. 

III. Fall Creek, Dr. 150. 

IV. Brookton, Dr. 8H and Dr. 9H. 

VIII. Spencer Lake ravine, Wv. lA. 

IX. Swartwood, Wv. 7B and wv: 6C. 

V. White Church, Dr. 9I. X. Glory Hill, Wv. 40 2• 
26 RECURRENT TROPIDOLEPTUS ZONES IN NEW YORK. 

XI. Waverly, Wv. 40 1 • 

XII. North Candor, Ow. 9A. 

XIII. Catatonk, Ow. 3G and 4G. 

XIV. Dean's tannery, Ow. lH. 

XV. Hawley Hill, El. 7J. 

XXI. Messengerville and East Virgil, Ct. 80, Rd. 5A1 

and Hd.' 6A. 

XXII. Marathon, Hd. 2D, Hd. 3D, Rd. 4D, Hd. 5D, 

and Hd. 3E. 

XVI. Water Street bridge (Elmira), EI. 2J. 

XXIII. Killawog, Hd. 2G and Hd. 3G. 

XXIV. Harford, Hd. 13E and Hd. 13F. 

XVII. Latty Brook, El. 2G. XXV. Harford Mills, Hd. 12G and Hd. 13G. 

XVIII. Breesport, El. IE. 

XIX. East Branch (Cortland), Ct. SE and Ct. SF. 

XXVI. Lisle, Hd. IJ and Hd. 2J. 

XXVII: ,Berkshire, Hd. i2L. 

XX. Blodgett Mills, Ct. S.L. 

Feet 

1.700 

IX 

;l_w:lrtwood Wv.7B 

i.i 1-:1 .,,..---,-..;;----,..j - - - - - - ----- - - - -

160()- . 

• 1500 

1400 

130Q 

1200 

1100 

1000 

Tropidcle~ 

'tus zone No.8 

lli 

lb' 

Wy .. !!C k la I, ~Dalma,nella danbyl zone 

Sections I, II, and III X 

(Taghanic, Glenwood, and Glory Hill 

Fall Creek) illustra~e (see Feet wv. 4<5 2 

fi 1300 

g. 3) the position of a 1;!. 

recurrent Tropidoleptus I 1.§' 

=~ zone (fa~nule Ith. IE, IA) :~ E 

which I regard as occur- -~'io 

ring lower than the zone ~ § 

No.1 of this report. This 120(r. 2nn ~~ 

zone is about 60feetabove """

1

"T,-r-op::.::.ido;;_iep--1- ~ 

. the Reticularia l:£vis zone, tus zone 

which ~s taken as the top N.o. 8 

of the Sherburne flagstone 

member. _ It lies in rocks uoo 

included in .the Ithaca 

shale member at Ithaca, 

but the typical fauna of 

the Ithaca member does 

XI 

Waverly 

w-v:4ol 

not appear in force till .1ooo 

about a hundred feet 

higher. , 

~~ In section III a sand- ~, lg, h,'), 

TropUlolePtus zone 1· stone band about halfway 

~: up contains the Spirijer soo Ol' 1 No.·2 

-;il mesistrialisfauna,and this 

.S' 

-~ band is supposed to rep-

~ resent the heavy-bedded 

sandstone at :Marathon 

and the Oneonta sand- ~oo 

stone of t4e Tioughnioga 

and Chenango River sections. 

Section IV (fig. 4) represents the stratigraphic 

FIGURE 9.-Sections at Glory Hill (X) and • · Waverly (XI). 

position of the Tropidoleptus zone No. 1 at Brookton, on the· 

north edge of Caroline, in the Dryden quadrangle. The upper 

beds of the Ithaca member terminate in the exposures in 

Sixmile Creek at an altitude of 1,025 feet (Dr.· 8G, 1e). A 

trace of the recurrent zone No. 1 appears on the edge of the 

hill s,outh of Brookton at an altitude of 1,410 to 1,435 feet . . FrGuRES.-SectionatSwartwood(IX). (Dr. 9H, 2a, and Dr. 8H, 2b). The dip, however, is strong to 

the south and it is estimated that it has carried the Tropidoleptus fauna nearly 200 feet lower 

than it would be at the Sixmile Creek exposure of the Ithaca shale member. It is estimated, 
GEOJ ... OGIC SECTIONS. 27 

therefore, that at this point the recurrent Tropidoleptus zone No. 1 is 600 feet above the top 

of the Ithaca mem her. 

Section V (fig. 5) shows the Tropidoleptus zone No. 1 about 200 feet below the top of the 

Enfield me:n:;tber. 

Section VI (fig. 5) shows the relations of the Tropidoleptus recurrent z.one No. 2. It lies 

a little more than 300 feet above the lowest beds of the Dalmanella danbyi zone, which forms the 

buse ~f the Cayuta member of the Chemung and which immediately overlies the Enfield member. 

Section VII (fig. 6) shows the.relations 

of the Tropidoleptus zone No. 1 to the 

base of the Chemung as seen in the West 

Danby section. lt lies 165 feet below the 

base. 

XII 

Nortn 

Candor 

Ow.9A 

Feet h-----1"'1 Section VIII (fig. 7) shows the relations 1300 ltEstimated 

of the Tropidoleptus zone No.2 to zone No. c~:uo;g 

3 in a nearly continuous se9tion, the two formation 

being about 400 feet apart. 

- Section IX (fig. 8) shows the Tropidoleptus zone No. 3 lying at the top of the 1200 _ 

Cayuta shale member in the section running ~~-~:A· 

southwardfrom Swartwood in the Waverly 

quadrangle (Wv. 7B, 1j). The section also 

includes an outcrop of the Dalmanella danbyi 

-

zone (Wv. 6C, 1a) about a mile sou~heast of 1100 le Swartwood; the particular part of this zone ~=====I Tt·opidolep- is not determined. All the outcrops are of tus zo11e No: I the Cayuta member of the Chemung, which 

is shown to be at least 600 feet thick. 

Sections X and XI (fig. 9) show the 

positions of the Tropidoleptus zones No. 2 1000 

and No.3, at the cliff to the west of Waverly 

and running up Glory I-Iill. From the dip . 

between the two sections it. is estimated 

that the Tropidoleptus zone No. 3 is approximately 400 feet above the apparent 900-:-

level of the Tropidoleptus zone No. 2, as at 

Spencer Lake ravine (section VIII). 

' Section XII (fig. 10) shows the Tropidoleptus zone No. 1 in the midst of rocks of 

the Enfield member of the Portage. The soo 

top of the Enfield (and base of the Chemung) is not exposed, but by calculation 

based on the position of the Tropidoleptus 

la 

\ 

\ 

\ 

\ 

\ 

\ 

J 

·~ \ 

~\ 

~ \ 

~ \ ~ d ,... .:a· ~ 

~ \ 

~ ~ ~ 

~ \ 

~ \ 

\ 

\ 

\ 

\ 

\ 

XIII 

Catatonk 

Qw.3Qand4,G 

Ow.4G lw 

()w. 3G, lc 

XIV 

Deans 

Tannery, 

Ow.lH 

lq and lr 

1

1 TropiJUJleptus zone No.2 

Ow. 211 In 

zone No. 1 in section VI it·li~s a little more 

th1111 1,300 feet above sea level. 

Section XIII (fig. 10) is all in the 

FIGURE 10.-Sections at North Candor (XII), Catatonk (XIII), and Dean's 

tannery (XIV). 

Cayuta member; no trace of the recurrent fauna was actually seen in this section. 

Section XIV (fig. 10) is also in the Cayuta member, but in it the Tropidoleptus zone 

No. 2 is well expressed at a little above 1,000 feet. From the measured distance of the Tropidoleptus zone No. 2 above the base of the Chemung at Bald Hill (section VI, fig. 5) it is estimated that the base of the Chemung here is as low as 700 or 750 feet above sea level. 

Sections XV, XVI, XVII, XVIII (fig. 11), representing the recurrent faunules in the Elmira 

quadrangle, present considerable difficulty. Sections XV and XVI, in the central and eastcentral parts of the quadrangle, show the relation of the Tropidoleptus zone No. 2 (El. 7J, 4n) 
/ 

R~CURRENT TROPIDOLEPTUS ZONES IN NEW YORK. 

to the Dalmanella danbyi zone and to the top of the Enfield as signified by the fossils. Throughout the Hawley Hill section (XV), ranging from 1,030 up to 1,625 feet above sea level, all the 

faunules are clearly Chemung, containing many specimens of Dalmanella tioga, D. carinata, 

and Douvillina cayuta, but so far as known showing no trace of Spirifer disjunctus. Sections 

XVII and XVIII show the positions of the Tropidoleptus zon~ No. 3. In these sections 

the recurrent zone (El. 2G: 1a, and El. 1E, 1a) IS near the axis of the Horseheads syncline, 

· whereas in the Hawley Hill 

Feet 

1600 

1500 

1400 

1300 

1200 

• 

1100 

-. 

-

XV 

Hawley Hili .EI. 7J , 

lw 

Leptostrophia 

nervosa zone 

I 

. 

lv. 

El. 7J 4n 

Tropidoleptus zone No.2 

"' Da.l11J,anella-- lc _twga_ 

1000 

El. 8J 

lx. 

Jr. 

lb 

I 

I 

I 

I 

I 

I 

I 

I 

xvrr A\TIII section (El. 7 J, n4) it is near the Water Street Bridge, Elmira 

Latty Brook. 

El. 2G: Br~~.sf~rt axis of the Elmira anticline; 

the stratigraphic distance between the two zones is thereI 

I 

I 

El. 2J. 

El. 2J 

5 

Dalmanella 

danbyi zone· 

.... 0 

El. 2G' ' la 

Tropidoleptus zone· .No.3 

I 

I ~\!E I / f±ropidolep-. 

I tus zone 

1 

]+Jo. 3 

. fore greater than, the actual 

difference in elevation. I have 

estimated that the first two 

represent ·the Tropidoleptus 

zone No. ·3 and the latter the 

zone No.2. 

All the Elmira s e c t i o n s 

(XV -XVIII) indicate consid- · 

erable chang~ in the composition of the faunules, making it 

difficult to locate with certainty the recurrent faunules. 

There appears to be a continuation of the Buchiola-Manticoceras fauna up to the stage 

following the Dalmanella danbyi zone. Spirifer disjunctus 

is extremely rare, appearing in 

only two faunules for the whole 

Elmira quadrangle; one of 

these is near the base of the 

Cayuta and probably above 

the danbyi zone; the other (El. 

2I) is near the top of the Cayuta. In both, the specimens 

are small for the species and 

the cardinal extremities are 

produced. 

Examination of sections on 

the east side of the Elmira 

quadrangle (El. 2J and El. 2K) 

]~ C1) 5 shows the succession from the 

,~jl' .5'~ . Dalmanella danbyi zone to the ]§~ § .~e. .... D. elmira and D. tioga zones 

FIGURE 11.-Sections at Hawley Hill (XV); Water Street bridge, Elmira (XVI); Latty Brook to be regular. But in 'the 

(XVII); and Breesport (XVIII). base of the section at Roricks, 

Glen west of Eln1ira (El. 7K)·, the Buchi~la-:Manticoceras fauna laps over the Dalmanella 

danb~i zone. In faunules El. 7K ~ncl 2L, Manticoceras and Buchiola are both found associated 

with Dalmanella tioga. It is therefore inferred that the Tropidoleptus zone No. 2 (El. 7J, 4n) 

lies at least 100 feet above the Dalmanella danbyi zone in the :Hawley Hill section (XV). 

The faunule El. 1E, la, is at least 400 feet above El. 4E, in which the prevailing Dalmanella is advanced beyond the D. danbyi stage of evolution and is therefore at appr?ximately 
GEOLOGIC SECTIONS. 29 

I 

the satne position in. relation to the evolution of. the Qayuta fauna as the Tropidoleptus zone 

XIX 

No. 3 farther east. The faunule El. 

'2G is approximately 400 feet higher 

than El. 4G, which contains Dal- Feet Ec~~t·~r;gch, 

Zz d b h l Ct SE d r· mane a an yi, and is t erefore a so 1soo 

tho equivalent of the Tropidoleptus 

zone No.3. 

Sections XIX (East Branch, 

Cortland), XX (Blodgett :Mills), and 

XXI (Messengerville and East Vir~gil, 1100 

I-Iarford quadrangle) indicate (see 

fig. 12) the position of the recurrent 

Tropidoleptus zone in the Ithaca 

n101nber for its eastern extension. 

In these sections the 'general Ithaca 1soo 

fauna pervades a n1uch greater thickness of strata than in the Watkins 

or Ithaca quadrangles. The heavy 

sandstone beds, which in these sections contain the earlier invasion of .

1500 

the Spirije1· mesistrialis fauna, serve 

as a guide in correlating the sections. 

This sandstone lies at 1,800 feet in 

section XIX; 1 at 1,400 to 1,420 in 

section X....\.:, and at 1,200 to ·1,225 in 

1400 

I 

I!" 

Ct. 8E 

le 

1Sandstone I 

Ct. SF 

lh 

'! 

\ 

I 

I 

I 

\ 

\ 

I 

\ 

I 

I 

\ 

I 

\ 

\ 

I 

\ 

I 

\ 

' I 

\ 

\ 

\ 

I 

I 

\ 

section XXI. The recunent Tropi- 1

Paracyclas \ 

doleptus zone for the latter two sections (Ct. 8L, 1q and 1r, and l-Id. 5A, 

la) lies 120 to 150 feet below the 

sandstone above mentioned, which 

rnay be called the mesistriaz.is zone. 

1300 

In section XIX the Paracyclas Zirata 

zone is approximately 400 feet below 

the mesistrialis zone, and so far as 

known the section does not contain 

the Tropidoleptus recurrent fauna, 1200 

which stratigraphically should. be 

· approximately 250 to 275 feet above 

the Parn.cyclas zone. . 

In sections XXII, L"{III, XXIV . ~ (the Marathon, Killawog, and I-Iarford noo 

sec.tions) the Leiorhynchus globuliformis fauna pervades the strata for 

300 to 400 feet above the 1~esistrialis 

zone. (See fig. 13.) 

In section XXVI (Lisle) the 1000 

Leiorhynchus fauna appears at 1,000 

lirata 

zone 

Ct. SF 

la 

\ 

\ 

'\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

I 

\ I 

\ 

I 

\ 

\ 

I 

\ 

I 

I 

I 

XX 

Blodgett Mills Ct.SL 

Ct.8L 

lx 

.Mesis.trialis \ , ,. zone \ 

lr 

R!f:::"~==ll 

· Tropidolep- \ 

\ 

\ 

\ 

\ 

tus zone \ 

\ 

I 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

XXI 

Messengervilieand'East Virgil' 

\ 

\ 

'Hd .. GA and 5A 'Ct. 80 

Ct. 80. 2h 

Ct. SO, le 

\ 

Hd.6A;2g 

Mesistrialis zone \ 

I 

I 

\ 

\ 

\ 

\ 

'\ 

\ 

\ 

\ 

\ :Hil. 5A,1a 

.Tropidolep- J tus zone 

feet and the Tropidoleptus recurrent 

N F:GURE 12.-Sections at East Branch, Cortland (XIX); Blodgett Mills (XX); and 

zone O. 1 at 300 feet higher. (See Messengerville and East V~rgil (XXI). 

fig. 14, p. '33.) 

'In section XIX of fig. 12 the sandstone Ct. SE, lr., is represented too low by about 30 feet. 

I 
30 RECURRENT TROPIDOLEPTUS ZONES IN NEvV YORK. 

In section XXV· (Harford Mills) it is believed that_ the Tropidoleptus zones (Hd. 13G, 

1k, q, r, and s) lying between 1,400 and 1,500 feet above sea level are the equivalents of the 

zones Hd. 2J, 1b, and 1e of section XXVI (Lisle) and of Hd. 12L, 1j, anclle of the section XXVII 

(Berkshire). (See fig. 14, p. 33.) These all are above the Leiorhynchus globuliformis fauna, 

'and according to my estin1ates are approximately 200 feet below the base of the Chemung of that 

region. Thus the Tropidoleptus zone No. 1, although ranging through a greater thickness of 

1400 

XXli 

Hd.5D 

r--"ld 

s::· ·.o 

-~ 

Hd. 4D ] lc ~ 

~Lei-.-or..:;.;hync'----hus-1. ~ 1300 globuliformis ~. . 1-l"az.one lief: 

r-1!-d. 3E,la 

1200 FHd. 3D, lq 

1100-

1000-

r--

Hd. 3D, b-e 

I--

Hd. 2D ·. lg' 

Mesistrialis zone 

Killawog 

Hd. 2G and 3G 

Hd.3G, i 

XXIV 

Harford Hd. 13E and 13F 

Hd. 13F. 

ty· 

1f .Hd.l3E _ _. 

·/Dlo ·-- • / la . 

] I . 

~ I 

~I ~I 

~ 

i'E Rd .. 2G, b-e. r;.J, 

Uorhynchlis 

globuliformis :one · 

FIGURE 13.-Sections at Marathon (XXII), Killawog (XXIII), and Harford 

/ (XXIV). 

strata in the Harford quadrangle, appears 

to have reached its climax near the san1e 

stratigraphic position in the sections in 

relation to the Chemung base. 

THICKNESS OF THE FORMATIONS. 

The sections illustrate the general 

relationship of the recurrent Tropidoleptus zones to the stratigraphy' of the 

several porti~ns of the area under investigation. They also illustrate the rapid 

· chang~s in the actual thickness of the 

sediments when 'classified by the fossil 

faunas which they contain. 

The sequence of the faunas appears 

to be the same throughout the region 

examined, 'but the relative thickness of 

sediments pervaded by the same fauna 

differs. The general difference observed 

is expressed by saying that the sediments occupied by the Genesee, Portage, and Chemung faunas diminish in 

thickness ~n passing eastward across 

these quadrangles, and that the Ithaca 

· fauna and· the zones carrying the recurrent Tropidoleptus or I-Ia1nilton fauna 

ea~h occupy less and less thicknesses of 

strata on passing from . east to west 

across the same region. The direction 

east and west is used because the north 

and south relations have not been 

studied in , sufficient detail ~o furnish 

evidence. 

Oscillation of considerable extent and frequency is shoWn by the changes in the prevalence 

of the faunas over the area, a fact whose elaboration and explanation furnish extremely interesting problems for anyone who n1ay follow up the matter. The facts already in sight suggest 

that over this particular are~ during the latter half of Devonian time the ocean currents 

repeatedly changed direction and that with the changes diverse faunas were made to occupy 

the area. 
GROUPING BY FAUNULES 31 

FAUNA. OF. THE SEVERAL ZONES. 

GROUPING BY FAUNULES. 

By gathGring the faunules into groups by zones certain general characteristics of the com,-

position of the fauna peculiar to each particular stage of incursion. into the region are recognized. Such a grouping of the fa~1nule samples is 1nade in the following table: 

Assif!nment ojthefmtmtles to the several zones. 

Tropidoleptus zone of the Ithaca shale member. 

Label. 

No. Locality. Quad- 1-minranglo. ~1~1_ 

G Ithncna ....................................... · ........................................................ Ith. 

!~ . :~~l'o·~~~~t-~~i~l·s-~ ·. ~ ~ ~ ~ ~ ~ ~ ~ ~ ~::::: ~ ~ ~ ~::::: ~ ~ ~ ~: ~::::::::::: :.:::::::::::::::::::::::::::::::::::::::::::: m: !~ . ~~~~~~~~~r-~i~l·o· ~:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::I ~~: 

Tropidoleptus zone No.1 (Enfield shale member). 

I 

7 West Danby ..... .-.............. _. ................................................. · ............ ' ...... . 

~~ ~~~e[t(iJi: : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : ·: : : : : : : : : : :•: : : : : : : : : : : : : : : : : : : : : : : : : : : :: :: : : : : : : : : : : : 

It h. 

"'"· Wv. 

26 Mount .Pleasant .......................................................... : ..................... : .... . Dr. 

27 Dryden Lake ......... · .............................................................................. . 28 ..... do .............................................................................................. . Dr. 

Dr. 

29 ..... do .............................................................................................. . Dr. 

30 East Danby ......................................................................................... . 31 ..... do ............................................... · ............................................... . Dr. 

Dr. 

33 White Church ....................................................................................... . Dr. 

34 Doputron Creek ..................................................................................... . 

~ . ~~~~g-~~~1~~~----· ~:::::::::::::: :·:::::::::::::::::::::::::::::::::::::: ~:::::::::::::::::::::::::::::: 

Dr. 

Dr. 

Dr. 

37 North Candor ....................................................................................... . Ow. 

38 ..... do .............................................................................................. . Ow. 

39 ..... do .............................................................................................. . Ow. 

i& .~??1~;:~~~~.:_:_:_:_:_ ~-.. -.. ~·::.~-~~ ~ :·: :_:_: :_·:: :·: :··.·:~: ~ ~:: ~ :·: ~:::: :·:·: :·::::::::::::::::::::::::::::::::::: ::::::: 

Ow. 

Hd. 

Hd. 

51 ..... do ..................................................................................... ····.·· .. . Hd. 

52 ..... do .......................................................................... ···· ...... ········.·· Hd. 

53 ..... do ............................ ·'· ................................ : ........................ : ...... . Hd. 

54 Center lJislc ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................ , ............... . 55 l.lslo ................................................................................................ . Hd. 

Hd. 

56 13orkshl rc .......................................................................................... . Hd. 

57 Maine ......................................... · .................................................... . Ap. 

Tropidoleptus zone No .. 2 (Cayuta shale member). 

j f~!J~!ti~::~)""··~ ~-~~ ~:~ ~ •••••• : ··~ •••••••• :: •• : •••••• : ••••••• •: •••••••• ~·····. : •••••••••••••••..• 

EI. 

EI. 

Ith. 

Wv. 

"'v. 

23 ..... do ............................................................................................... . wv. 

24 ..... do ............................................................................................... . Wv. 

32 l3ald 1\{ountain .................................. .' .................................................... . Dr. 

!~ . ~~v-~fg.' .':::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: Ow. 

Ow. 

48 lJapoor ............................................................................................... . 00 Apalachin ............................................................................................ . Hd. 

Ap. 

1E 

8L 

8L 

5A 

5A 

3K 

1B 

4D 

9B 

3D 

3D 

3D 

llH 

llH 

81 

121 

9J 

9J 

9A 

9A 

9A 

14C 

13G 

13G 

13G 

13G 

13G 

71 

2J 

12{, 

4D 

8J 

6L 

15N 

1A 

40 

40 

40 

71 

1I 

II 

8C 

13L 

Collector's 

notebook 

designation. 

1a 

1q 

1r 

1/ 

1a 

Ig 

la 

lee 

H 

1o 

1b 

1d 

1e 

4b 

1p 

IK 

1l 

im 

1 

1k 

lq 

1r 

18 

1v 

1e 

1l 

1g 

4n 

1q 

1a 

1l 

lb 

1g 

1} 

1n 

1d 

1d 

2a 

1 

Elevation 

abova 

sea level. 

Feet. 

410 

1, 286-1,300 

1,300-1,315 

1,045 

1,048 

1,085 

1,020 

1,030 

1,405-1,410 

1, 685-1,690 

1, 700 

1, 723 

1, 475-1,485 

1, 495-1,505 

1,300 

1,375-1,395 

1,273-1,288 

1, 288-1,298 

1,075 

1,095-1,102 

1,102-1, 109 

1,025 

1,420 

1,470 

1,475 

1,48S-1, 495 

1, 5\)6-1, 530 

1, 410 

1, 358-1' 3(\9 1,165-1,170. 

1,041-1,055 

1,075 

1,000 

1,444 

1,175-1,185 

850 

870 

885 

1, 778 

1,010-1,020 

1,010-1,020 

1,800 

1,180 

a In the ro_cks In tho neighborhood of Ithaca other traces of the Tropidoleptus fauna have been found. They all appear to have come from ncar tho horizon where wo have drawn tho boQildary between the Sherburne and Ithaca members; but their exact location is not recorded. They 

may be designated as follows: B, base or Buttermilk Creek ravine, Cornell Museum No. 10457; C, Cascadilla Creek near base; D, Burdicks Glen, at altitude 770fcet above sea level; E, hillside north of 1\feKinneys in the Ithaca member. · b Tho Blodgett Mills and Messcngervillc faunules here given are both preceded and followed in the section by species common in tho Ithaca fauna. 

" 
32 .RECURRENT TROPIDOLEPTUS ZONES IN NEV\7 YORK. 

Assignment of the jaunules to the several zones-Continue<:!-

Tropfdoleptus zone No.3 (Cayuta shale member). 

Label. 

No. Locality. Quad- 1-minrangle. bt:!1. 

1 Breespo,t .................................. : ... o •••••••••••• : •••• : •••••••••••••••••••••••• • ••••••••••• .l El. :i ~ I.i~~~~·~': ~.:.: ~ ..... ~ .. : ..:: ~ ~ .. ~::: ............ : ..... : ............... : ........ : ..: ...... :. ~~. 13 AustinHill .................................................................. c ••••••••.•••• · ••••..••••• Wv. 14 .... ,do ................................................................................................ wv. 15 ..... do ................................................................................................ Wv. 17 North Chemung ............ __ ..... _ ................................. _ ..... _ ...... ~ ................... _ Wv. 

H t~!I~~r~<:•:: · ,:•:_.·:: .. ·::··: :-· ::::·::::·•: : :·:· .. :: ·: .. ·: :·: ·· *~• 25 Glory Hill, Waverly .................. ____ ................. -.·- ....... -........ ____ ..... ---.- ............ Wv. 43 Osborn ....................... ; ......................................................... _.............. Ow. 

ft 63 .r~J~~~·;::·:: Tracy Creek, southwest : ...................................................................... : :_:.::•-- :···: -:·_:.:··.:·: :••••·•··•·····• •··•-··•• : ···:·.• ........ n Ap. 

GROUPI~G BY SPECIES AND GENERA. 

1E 

2G 

8J 

1A 

6B 

7B. 

7B 

7B 

llH 

141 

3J 

3J 

9N 

40 

120 

llE 

8G 

5N 

6N 

60 

Collcc- Elevation 

tor's above note- sea level. 

book 

designation. 

Feet. 1a 1,420 

ia 1,345 1n 1, 415-1,420 

1vvv 1, 565-1,570 1a 1,561 

1j 1, 610 1j2 1,610 

lj3 1,610 

1a 1,440 1d 1,500 ld 1, 345 2a 1,339 

1aa 889 

2nn ·1,165-1,170 

lp 1,112 la 1,500 3a 1,490 1c 1,300 lo 1,402 4 1,600 

in the. accompanying. table the several species and genera identified in the sample faunules 

are tabulated together, in or'der to show the frequency of appearance. of each in the whole 

series and in separate zones. . . . 

The· table shows about 20 genera of brachi<;>pods, about 30 genera of pelecypods, and 

about 20 other genera, chiefly gastropods. A few species are ~epresented in a large number of 

the samples; but the great majority of the ~pecies, and even genera, 'are represented in so few 

faunules and are so irregularly distributed by zones as to suggest that they are of slight 

significance. Of the 87 names tabul~ted only 23 ·appear in as many as 10 of the 63 faunules, 

·and only 11 names appear in 20 or more of them.' 

· Two explanations may be assigned for this rarity of specimens common to the faunules: The 

great majority of the species listed may (1) be merely representatives of the general Devonian 

fauna which have accidentally gotten into these particular samples; or (2) they ~p.ay really be 

very rare in that fauna and therefore only accidentally found in any sample. In the latter 

case they may be of greater significance than is at present apparent; but in neither case is their 

significance evi_den t. 

In ·several genera I have gathered closely related species, the differentiation of which is 

significant for the purposes of this paper. For instance in bringing four species of Productellainto the order of sequ~nce as listed, general indication of the actual succession is expressed. So 

the camarotrechias pass evidently from the 0. congregata type through the 0. eximia-stephani 

into the 0. sappho-contracta group. In citing Chonetes, the specific names setigera-scitulus are 

united by hyphen; this is to indicate that there is no evident and sharp distinction between the 

forms which have been often cited as distinct species under these separate names. 

In some genera (Productella, Camarotrechia, Leiorhynchus, Leptodesma, Modiomorpha, 

Loxo~ema, and perhaps some others) the considerable amount of fluctuation in characters 

observed calls for deeper investigation in order to determine to what extent the differences are 

purely fluctuating variations.and to what extent they are of specific value. In the table I have 

indicated by a check every definite indication of the presence in the faunules of each genus (or 

species). In regard to a few of these the evidence is slight, and future and larger collections may 

compel revision of the list. Undoubtedly fuller collections will show a more general presence 

of some of the species named than I am able to record at the present tin1e. 
List of genera and species in thejaunules, by zones. 

I ~~ ~~ 

I Zone in Ithaca shale member. Zone Xo. 1 (in Enfield shale member). Zone Ko. 2 (in Cayuta shale member). Zone No.3 (in Cayuta shale member). 

-------------1:._6

_ ~~~~:~~~~~- ~ ~~ ~ ~~ .:"_:~'-='-1" !~ ~~_:_ _:'_l~l~!~l_:"_lj~l~b .. ·~;--=- ~ ~!--'- _a_!_o_l~!-='-1~1_:'_ ~~~:__._ _

1

_: --'-!j~'~:~·~!~l~l~l~~ ~~~~~'"1'·1_:0~1~ Tr~p~doleptus ........................ _I_ ........... ~ X j X X I X . . . . . . . . X . . . . X X X X :. . . . X X I X X . --- X X X i X l, X I X X X I X l X X i X : X X , ---- ----. X I X ---. j X X X I X 0 .. J .. .' X i.... X X : X .... • X I_ ... 1 X I X I X X X X X X X ~ X I X 

Rhi_pidome_lla .......................... ! X X!········· ............ X X X X X X X X I X · X X X X X X X ···· ···· ···· 1•••• X X X 1 X X;····-··· .... 1 X X X j----1 X! X X X.----, X X. X .... X .... ,X X X; X X ......... X ........ X X ........... . 

~~g~·~_-_-_-_·_~::::::::::::::::::::::::::: :::: ~ :::: :::: :::: :::: -~- :::: :::: :::: :::: :::: :::: :::: :::: :::: :::::::: :::: :::: :::: -~- :::: :::: :::: :::: :::: :::: :::: :::::::: :::: :::: :::: :::: :::: -~- :::: :::: :::: :::: :::: :::: :::: :::: :::: -~- :::: :::: -~- :::: :::: :::: :::: :::: :::: :::: :::: :::: ·x· :::: :::: :::: :::: :::: ~::;~~~::::::::::::::::::::::::::: :::::::::::::::::::::::::::: -~- :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: ·x· :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: 

Phthonia ................................................................................................................................................... -... -- - ---- ---- -... --- - ---- . --- -- -- ---- -- . - --- - ---- -- -- --- - --- - -. -- -- -· ---- ---- ---- X --- - X --- - ---- ---- -- -- -- -- ---- --- - ---- ---- ---- --- - ----

~J~J~~~~~~~~~~~~~~~~~~~~~~~~~~~~~: ~::~ ~~~~ ~::: :::::::::::: :::: :::::::: :::::::: :::: :::: ::~: :::::::: :~: :::::::: ::~: :::: :::: :::~ :::: :::::::: :::: :::: :::: :::::::: :::::::: :::: :::: :;: :::::::::::: :::: :::::::::::: :;: :::::::: :::: :;: :::: :::: :;: :~: :::: :::: :::: :::: :::: :::: :::: :::: :::: :::: :::: :::: ::~~ Euthydesma ....................................................................................................................................................... ---- ---- .... ---- ---- ---- .... ---- ---- ---- ---- ---- X ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ----

~~~1in.l~~t/\Y ~~~ :) ~: ~~ X Y ~~~ ::~~ ~:: Y :·:: :::: Y E ::~: < :~· iii ::~ ::: < :::: Y ~~~ •:: :::: i <E.~.::: / ::•: ::: i • i ~ < :::::: :: : ::: U < :: i ~ !! :: Y ·~· ·~· !! ! Y -~ iii :::•: :: / .~. :: Y < ••::·~· •: i :: 

f~T-mF: >< > Y Y < ::::Y iili F i/ :·:: ··:·~1: ~:: :r: } ::: :::: :~: U •::: .1: Y ::• V :::•: .• U > > :1 :::• U :·:: ·~· :~:: : ::• ; / :•• // :~ ~: / •••• ;{ \ DE} / / < > :•:< :~ :! < > :::• :! ·~· : Y ~~~1~~.- ::: •• : •. : .: -~-} : :::. :: t ~: :::r :: :• \: ::.} : ::•::: ::: ~:} .~ :••· :: •:• :. :.: ::: ::.~ ::::: . :. :~: .~. -~- • :~:) •~• :::: :::::.~: • ···• :~• :~ E :~ : ) ~ t t} .~. : : -~- :::: 

Murchisonia ................................................................................................................................................... ---- ---- ---- -- .. ---- ---. ---- ---- ---- ---- · ·-- ---- -- ·- · · · · ---- ---- · · · · · · · · · · · · --- · · · ·- ·- ·- ---- ---- ---- ---- X · · · · · · ·- · · · · ---- · · · · · · · · · · · · · · · · 

~~~~;~::~-:_-_-_-_·::::::::::::::::::::::: :::: :::: :::: :::: :::: :::: :::: ·x· :::: :::: -~- :::: :::: :::: :::: :::: ·x· :::: :::: :::: :::: :::: :::: :::: :::: :::: :::: :::: :::: :::: :::::::::::: :::: :::: :::: ·x· :::: :::::::: ·x· :::: :::: :::::::: -~- :::: :::: ~ :::: :::: :::: -~- :::::::: ·x· ~ ~ :::: ·x· :::: :::: ·x· :::: ·x· 

Platyceras . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . X .... -.. - ..................................... --- --. - ---- -- -- -· · - -- -. ---· ---- --- - ---· ---- --· - · · · · X · · · · · · · · · · · · · · · · · · · · · · · · X · · · · · · · · · · · · X · · · · · · · - X · · · · · · · · · · · · X X X · · · · · · · · · · · · 

Fenestella . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . X ................................................ I •••.•••••••• 

i.~:~::::::::::::::::•::::: ::: :::: :::: ::: ::: :: ::: ·~- :::: ~: :::: :: •• : ••• :: . : ::. ·~· •• : •••. -~· :: :: \•: :: • : •••• :::: > ••••• ·~· :: ••• ::: .~: : .:. : : :: :•: : ·: • :::: • :•.• •• :::.::: } :·::: •• ::• ••••••• :~ :: ::: •: ••• ·~- : J:~: : :::: 

67437°-NO. 79-13. (To face page 32.) NOTE.- Crania leoni, not given in the list, occurs in fauna 10, and Monotrypa sp. in fauna 12; Productella boydi is checked on line" P.lachrymosa, etc.," and P. rectispina on line "P. hirsuta.'' 
GROUPING BY SPECIES AND GENERA. 33 

In preparing the list I have used only the generic names in a large r.umber of cases In 

order to bring out the degree of similarity in composition of the several samples. The considerable a1nount of fluctuation expressed by the char~cters used by authors in defining species would 

necessitate the frequent use of a question mark in place of a positive check if the name of the 

species were to be cited. This uncertainty as to the specific identity of the specimens, however, 

1nay not indicate uncertainty as to the presence of forms of a common race or common origin, 

and it is identity of race w_hich is the 

significant fact indicated in this table: XXV 

In regard to genera, whicl~ appear but Harford 

l F t Mills infrequently among the samples, t 1e ee 

1600 facts are correct so far as they are stated; 

but they are deficient in furnishlng 

testimony regarding the common composition of the sam})les so far as such 

genera are concerned, and of course 

also as to the particular species of the 14 

genera. B:u tin regard to genera which 

reappear in a majority of samples and 

outside these particular zones do not 

appear in the faunules of the same section, the evidence is clear that the genus 13 

.is an intrinsic part of the faunal group 

the recurrence of which I am considering. Whether the species of the genus 

have fluctuated or evolved differences 

with en.ch return of the fauna is a 12 

question which can not be properly 

examined until the common source of 

the specimens compared is thoroughly 

00 

00 

"'" 

established. 

Only such genera, ther~fore, asap- 11 

pear in such a large number of the samples from each zone (and also in each 

00 

OQ 

Hd. 13G 

ls 

lk 

'' 

Hd.12G ln 

ld: . 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

' ' 

\ 

\ 

\ 

' 

\ 

\ 

\ 

\ 

\ 

\ \ 

\ 

\ 

\ 

\ ... \ 

\ 

' \ 

\ 

\ 

\ 

\ 

\ 

\ 

XXVI 

'Lisle 

Hd. 2J and u. 

Hd.2J 

.le 

lb 

Hd.lJ· lc " .. 

\ 

\ 

\ 

\ 

\ \ 

\ \ 

\ \ 

XXVII 

Berkshire 

ltd:t2L 

\ \ 

\ \ 

\ \ 

\ \ 

\ \ 

\ \ 

\ \ Hd.t2L \ \ le 

\ \ ~~~) I= ~ff \ li~ \ lt ·e;., 

of the successive zones) as to leave no 

doubt of their intrinsic place in the 

constitution of the fauna can be used 10 

as giving positive indication of common 

origin and continuity of genetic relationship during the successive shiftings FIGURE 14.-Sections at Harford Mills (XXV), Lisle (XXVI), and Berkshire 

(XXVII). of the faunas from zone to zone. Other 

genem may be added by more thorough 

explorations of the beds containing the fossils, but they must be left out of the investigation 

until their place in the faunules is thoroughly established. 

The imperfection of evidence in the case of the Tropidoleptus zone of the Ithaca member 

is. such that, although first in order of time, its consideration will be omitted until after the 

other three zones have been examined. (See pp. 71-72.) 

67437°--~o. 79--13----3 
34 RECURRENT TROPIDOLEPTUS ZONES IN NEW YORK. 

EVIDENCE OF RECURRENCE. 

TROPIDOLEPTUS ZONE NO. 1 (ENFIELD SHALE MEMBER). 

Tropidoleptus zone No. 1 is expressed in twenty-six faunules (see· table, p. 29). At least 

eight genera are represented in twelve of these, and no other genus appears in more than nine' 

of them. · · 

Number of faunules containing the more abundant genera and species of Tropidoleptus zone No. 1. 

Tropidoleptus ...................................... 21 Chonetes._·_ ............................... __ ........ 12 

Rhip:i.domella .............. ·_ .................. --- ... 21 Productella ............ __ ... __ . __ .. __ .. __ .......... 13 

Delthyris ................................ _ . . . . . . . . . 22 Leptoclesma... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 

Ambocrelia. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Mocliomorpha.· ..... :................. . . . . . . . . . . . . . . . . . 9 

· Camarotrechia ...... _ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Pleurotomaria ................... : . ............ _ .. _ . . 8 

Spirifer marcyi ............................... : . . . . . . . 13 

The first eight genera may be considered fairly dominant in the zone; at least they show 

the highest degree of frequency of appearance in the collections from this zone now in hand. 

Sixteen of the twenty-six samples contain five or more of this group of eight dominant genera;· 

in detail, three faunules co.ntain eight of the dominant eight genera; two contain seven; seven 

contain six; four contain five; seven contain four; and' three contain three. 

All these genera were represented by the same or closely related species at an earlier stage 

in the Hamilton foi·mation in the region immediately north of the area from which these 

samples came; It isJ therefore, reasonable to assume that these eight genera occurring in the 

. fauna of the zone No. 1 were descended directly 'from Hamilton species or fron:i species havin.g 

a common source with Hamilton species. 

The zone No. '1 is surrounded both below and above by rock containing the species peculiar 

to the Buchiola-Manticoceras fauna of the Portage, from which it is not reasonable to suppose 

that these eight species could have directly descended. 

TROPIDOLEPTUS ZONE NO.2 (CA"Y:UTA SHALE MEMBER). 

The zone No. 2 is represented in twelve fauriules. Eleven genera and species are found 

in six or more of these. 

Number of faunules containing the more abundant genera of Tropidoleptus zone No. 2. 

Tropidoleptus ...... : ..... _·_ .. :..................... 8 Camarotrechia ............ , ......................... 11 

Rhipidomella ..... -- ..... __ .. . . . .. . .. . . .. . . . .. .. .. .. 8 Leiorhynchus ..................... __ . __ ........ __ .. . 7 

Schizophoria .................... ·_.................. 6 Productella ............................. :·_.......... 9 

Spirifer marcyi ............ , .--: ____ .................... S Cypricarclella ...................... __ : ......... __ .. 8 

Delthyris ........................................ ~. 9 Mocliomorpha ........... -. . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 

Ambocrelia ....................... -..... -.. -... -. --. 7 

Only two of the twelve faunules ha:ve less than s~ven of the above eleven genera in their faunal 

composition. One faunule, No. 32, has all eleven, and four have as many as eight of them. 

TROPIDOLEPTUS-ZONE NO.3 (CAYUTA SHALE MEMBER). 

The, Tropidoleptus zone No. 3 is represented i11 twenty faunules. Eleven genera are found 

in eleven or more of these, and eight appear in twelve of the twenty, constituting the dominant 

character of the fauna. ' 

Number of faunules containing the more abundant genera of Tropidoleptus zone No.-~-

Tropidoleptus ..................................... · 16 Delthyris: ... -.. --................................. 17 

Rhipiclomella ........ __ ........................... 11 Productella ...................... :................. 12 

Schizophoria ........... · ........................... -12 Atrypa ... -........................................ 11 

Dalman ella .... :.... . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . 10 Camarotrechia............... . . . . . . . . . . . . . . . . . . . . . . . 12 

Spirifer marcyi.. ............ __ ..................... 14 Cypricardella .................... :.. .. .. .. .. . . .. . . . 13 

Chonetes .................................... ·. . . . . . . 12 
RECURRENT TROPIDOLEPTUS ZONES IN NEW YORK. 35 

SUMMARY. 

The occurrence of the Tropidoleptus fauna and its associates is sumn1ed up as follows: 

Num,ber of ja1mules conta·ining the ·more abundant genera in the three recurrent zones .. 

Genera. ZonoNo.l. Zone No.2. Zone No. 3.1 Genera. Zone No. 1. Zone No.2. Zone No.3. 

21 8 16 Schizophorio. .................... 3 6 12 

21 8 11 Leiorhynchus ................... 4 7 4 

22 9 17 Cyprico.rdello. .................... 2 8 13 

15 7 6 :Modiomorpha ................... 9 6 5 

19 11 12 Dalmanclla ...................... .. ~ ... -... -.. -. 5 10 

13 8 14 Atrypa .......................... 5 4 11 12 5 12 

Tropidoleptus ................... . Rllipidomclla .................... . Delthyris ........................ . Ambocoolia ...................... . 

~~~frgr:~~~~if~::::::::::::::::::: Productella ...................... . 13 9 12 Total number of faunules .. 26 12 20 

Only fourteen genera occur in 50 per cent of the faunules of some one zo~e. I have included 

Chonetes in the lot of zone No. 1, although so far it has been found in only twelve of the twentysix faunules and, st.rictly, one more occurrence is necessary to bring it up to the 50 per cent. 

SzJirifer marcyi is treated as a generic group and separated from the other spirifers because its 

specific characteristics are so closely differentiated in th_e Hamilton that it may safely be treated 

as genetically distinct fron1 the other racial lines of Spirifer appearing after the Hamilt6n epoch. 

All the other species may be passed over until some other evidence can be adduced to show 

that they properly belong to these particular faunules. 

Exmnination of the several genera nained .gives grounds for refusing to consider some of 

thmn as recurrent expressions of a common magna fauna associated with IIamilton. 

Ambocrelia shows a decidecl falling off on passing upward into zone No. 3, where it shows 

itself in only six of the twenty samples. This genus was present in all but..four of the twenty-five 

separate faunules of the Marcellus and Hamilton recorded by Cleland.1 It seems reasonable 

to suppose, therefore, that its origin is from the same source and that its absence from many 

of the late· Chemung faunules is coincident with its general decadence; since, as a ·genus, it is 

not reported after the Chemung. · It may be retained, therefor:e1 as probably having its source 

fron1 the llamilton magna fauna, 2 although it is not restricted to these recurrent zones in the 

Upper Devonian. 

Chonetes is so frequently met. with in other faunas of the Upper Devonian that I think it 

n1ust be omitted fron1 the list as of doubtful origin .. 

'fhe fact that the Productella types of the zone No. 1 are more closely related toP~ spinulicosta, which is comn1on in the IIamilton below, than to the species common in_ the general 

Chmnung fimna, leads me to think that its appearance in the zone No. 1 is due to direct descent . 

. fron1 llanulton representatives of the genus. The new types of the genus, which are abundant 

throughout the Chemung, may have taken their origin from the Spirifer d:isjunctus fauna of the 

Iowa and western region, or they may be accounted for by the nlingling of the two lines of 

·descent; foi· the present they may be held in the list. 

Schizophoria is very rare in the zone No. 1, and is not recorded by Cleland as being present 

in the UJlderlying llan1ilton. It is also an abundant species in the general Chemung fauna 

and in the Upper Devonian is associated with Spirifer disjunctus. I conclude, therefore, that 

its appearance in the recurrent faunules is to pe accounted for otherwise than by descent from 

the I-Iamilton 1nagna fauna. It should therefore be omitted fron1 the list. . 

Dalmanella for the same reason may be excluded, and Atrypa., although it may have come 

.frmn I-Ianultonian ancestors, may as likely have been derived fron1 the Spirijer disjunctus fauna. 

It is not pecu1iar to the three zones. . 

Leiorhynchus, Cypricardella; and Modiomorpha are at least doubtful, as they are so rare 

in the zone No. 1. They should be excluded in absence of good reasons to the contrary. 

After this first critical exclusion of genera from the list on account of .their unsatisfactory 

den1onstL'ation of IIamiltonian ancestry, there ren1ain only. Tropidoleptus, Rhipidomella, Del-

• Cleland; H. P., A study of the Hamilton fauna of the Cayuga Lake section: Bull. U.S. Geol. Survey No. 206,1905, p. 97. 

2 On t.ho fossil faunas of the St. Helms breccia: Trans. Roy. Soc. Canada, 3d ser., vol. 3, 1910, p. 241. 
36 RECURRENT TROPIDOLEPTUS ZONES IN NEW YORK. 

thyris, Camarotrechia, Spirijer marcyi, and PrQductella. With the evidence at hand the presumption is that the above six genera constitute an essential elen1ent of each of the faunules 

occurring in the Tropidoleptus zones Nos. 1, 2, 'and 3, and that they are genetically allied to 

the underlying _general Hamilton magna fauna. 

Examination of the .list shows that the genera fall into two classes. Tropidoleptus, 

Rhipidomella, and Spirijer marcyi, so far as my search has extended, are found abov:e the 

Hamilton only in the recurrent Tropidoleptus zones Nos. 1, 2, and 3. Delthyris, Camarotrechia, 

and Productella, on the other hand, although very commonly present in the recurrent zones, 

appear also in other parts of the sections where the :first, three genera are lacking. 

The range and distribution of these last three genera are significant and interesting and 

call for further investigation. In general the facts indicate that the latter three genera entered 

the area with the rest of the recurrent fauna, but that instead of departing with it, when the 

conditions coincident with entrance were withdrawn, they remained on the ground and suffered 

· evolutional modification. The first three genera, on the other hand, persistently retained their 

typical characters, suffering a very slight modification of form, and. thus ·mark the narrow 

limits of the conditions appropriate to their existence. 

The genera, except Productella and including Cypricardella, will be critically examined 

to make sure of their relationship to the antecedent Hamilton fauna and of their title to 

be regarded as recurrent representatives of that fauna. Productella is omitted, because, 

though a dominant representative of . the recurrent faunules, it is not separable from its 

representatives outside the zones of recurrence. The genus Cypricardella, however, is included 

because in two of the zones the species C. bellistriata, a Hamilton species, is diagnostic of the 

Tropidoleptus fauna. 

GENUS TROPIDOLEPTUS. 

CONTINUITY OF THE GENUS. 

The fact that. Tropidoleptus differs so widely from any other genus of brachiopods is, on 

the face of 'it, strong evidence of the racial continuity of the Hamilton representatives into the 

later Upper Devonian beds of the New York area. Further, although it is probable that the 

identity in the generic characters of ·the Hamilton and the Upper Devonian species is sufficient 

to establish the recurrence of the ·genus, I have thought it well to set down here all available 

evidence be~ring on the continuity of the race, designing thus to furnish a solid ·foundation for 

·future study of the paths of migration of the fauna with which it is associated. Accordingly 

I have examined critically not only_ the generic but the specific and fluctuating characters 

expressed in the recurrent zones, comparing thenl with the typical characters expressed by the 

Hu.milton representative of Tropidoleptus carinatus. I have not considered it necessary to bring 

into the present paper a comparison of these representatives of the genus. with representatives 

from distant regions, interesting though this would be, as to do so properly would require the 

examination of snecimens which are not at hand for study. 

SPECIFIC CHARACTERS. 

In the literature all the Hamilton representatives of the genus Tropidoleptus Hall h~ve 

been assigned to the one species ·T. carinatus. By this assignment specimens differing in several 

respects are included under one specific name, the differences being held to be unimportant 

or of so fluctuating a character as not to entitle them to specific or even varietal discrimination. 

For taxonomic classification the consta.nt characters may be regarded as of generic or of higher 

rank; they include, of course, those indicative of specific rank. 

The species Tropidoleptus carinatus (Conrad) was originally defined by Conrad 1 in 1839 

under the name Strophomena carinata as follows (no figure was given): 

Shell suborbkular, with from 16 to 18 angular radiating ribs; superior ·valve with a sinus in the middle; inferior 

valve angulated in the middle, slightly flattened on the side; base prominent and subangulated in the middle; basal 

margin sinuous. Length, ! inch. · 

Localities: Helderberg Mountain, in limestone; Ludlowville. 

1 Third Ann. Rept. New York Geol. Survey, 1839, p. 64. 
GENUS TROPIDOLEPTUS_., 37 

In .1857 Ja1nes I-Iall 1 defined the genus Tropidoleptus, taking Conrad's species as the type 

and publishing two illustrations of Tropidoleptus carinatus. He gave the geologic posi~ion 

and locality for the species as follows: . -

In the H~milton group in Schoharie County, and at Eighteenmile Creek on Lake Erie; upon the shores of Seneca, 

Cayuga, and Canandaigua lakes, extending, in fact, throughout the. entire breadth of the State from near the Hudson 

River on the east to Lake Erie on the west. It likewise occurs in rocks of the same age in Illinois and Iowa. 

FLUCTUATING CHARACTERS. 

If it be assun1ed thn.t the figure published by I-Iall in 1857 is the type figure of the species, 

and that the figures given 2 in the full illustratio~ of the species in 1867 represent a single spe-· 

cies, it is evident that in several respects the characters are fluctuating. In I-Iall's Plate LXII z 

figures 3j and 3k are of the san1e form as the two figures published 3 in 18.57 and may furnish 

a bnsis for discritninating n.. typical variety of the species, Tropidoleptus. carinatus typicalis, in 

which the cardinal angles are rounded; the angle forn1ed by the lines of growth of the sides with 

the cu.rdinal angle is 90° but not greater; one strong central plication is on the convex vnlve; a 

slight sulcus appenrs in the center of the concave valve; 10 plications are visible at each side 

of the median rib on the convex valve; and the bifurcation of plications is not evident. 

· A second variety n1ay be recognized 2 in figures 3t, 3w, 3u, and 3x. In these the cardinal 

angles are slightly produced beyond the lateral margin, and the angle fonned by the sides witl;t 

the cn.rdinal lines less thnn a right angle. This variety may ~e called Tropidoleptus carinatus 

alpha. 

A third variety is represented 2 by figures 3p and 3r. In this forn1 the length of the 

cardinal border is decidedly less than the greatest diameter at about the nuddle of the shell, u 

and the angle forn1ecl is greater than a right angle. The form may be called Tropidoleptus 

carinatus beta. 

A fourth variety is expressed 2 by figures 2a, 2b, aud 2c, in which the sides are approximately at right angles with the cardinal border, but the width of the shell is less than or equal 

to the length, producing an elongate shell. To this form may be given the. name Tropidoleptus 

carinatus gamma. 

A fifth vu.riety is expressed 2 by figures 3d and 3e, in which the nuniber of plications exceeds 

the typical nmnber; the n1edian rib is not conspicuously larger than the adjacent plications; 

the cardinal angle is slightly n1ucronate and is less than a right angle. This form may be 

called Tropidoleptus carinatus delta. 

A sixth variety is represented 2 by figure 31, a large valve in which the plications near the 

front 1nargin abrup.tly bifurcate. Its general forrn is that of the variety of typicalis. It may 

be called Tropidoleptus carinatus epsilon. · 

Examination of 1nany sets of the species from the Hamilton leads to the conclusion that 

th~se several varieties n.re not differentiated sharply from one another but are expressions of 

varying stages of fluctuation of n1ore or less normally plastic characters. Nevertheless, as 

fluctuating characters they serve the purpose of distinguishing different expressions of the 

species, and hence of the tendency toward modification observed in the subsequent history of 

the race in the New York Basin. 

The question whether the fluctuating characters are of specific or varietal rank is largely 

a mntter of opinion, to be answered variously by students according to their personal prejudices. It is, however, in1portant to examine ,critically the fluctuating characters in order to 

ascertain what, if any, effect has been produced by the passage of time, and what may be the 

nor.mal amplitude of fluctuation at each stttge in the history of the race. 

1 Tenth Ann. Rept. New York State Museum, 1857, pp.151-152. 

2 Paleontology: Geol. Survey New York, vol. 4, 1867, Pl. LXII. 

a Tenth Ann. Rept. New York State Museum, 1857, p. 152. 
38 RECURRENT TROPIDOLEPTUS ZONES IN NEW YORK. 

STATUS OF FLUCTUATING CHARACTERS IN ZONE NO. 1. 

. ' 

Specimens e:{amined.-In order to determine the status of the fluctuating characters in 

Tropidoleptus zone No. 1, I have taken one of the faunules (No. 50, Harford :Mills section, Hd. 

13G, 1r) from which a considerable number of specimens have been obtained in good state of 

preservation. The locality is in the Harford· quadrangle, on the eastern side of the Watkins 

Glen-Catatonk distriet. 

From this faunule I have selected and mounted on tablets for study 8.8 specimens of 

Tropidoleptus. (See Pis.· I, II.) They are_ all represented by sandstone molds, fron,1 which. 

the calcareous shell itself has been leached off in weathering. They present, therefore, a different 

appearance from ·the figures illustrating the. original description of the IIan1ilton species; 1 

but they exhi.bit, nevertheless, in very good state, the surface oharacters of both the interior· 

and exterior of both valves and furnish good basis for comparison .of the characters represented. 

Specimens 1 to 27 (Pl. I, figs. 1-27) exhibit interior molds of pedicle valves; 28 to 38 

(Pl. I, figs. 28-38), exhibit interior molds of brachial valves; 39 and 42 to 88 (Pl. I, figs. 39 

and 42-64, and Pl. II, figs. 1-24) show exterior molds of brachial valves; 40 and 41 (Pl. I, figs. 

40 and 41) show exteriors molds of pedicle valves. 

. The primary reason for iilustrating the fauna by molds instead of by the actual shells is 

found in the nature of the sedimentsJ in which the latter were buried. The specimens upon 

which the specific original- descriptions· were based were fossilized in a soft :q1ud shale. The 

soft shale weathers much more readily than the. shell substance, and the shells are easily 

removable from the sediments. · 

The specimens in the IIarford Mills section,· on the other hand, were embedded in a finegrained sandstone, originally calcareous. In the process. of leaching the calcm:eous matter 

of specim~ns lying near the surface was dissolved and carried away, leaving only the rnolcls; 

these, however, owing to the fine-grained character of the rocks, exhibit with great faithfulness 

the surface characters of the shells. Deeper in the same section is a tough calcareous sandstone, to which the shells adhere so strongly that atten1pts to extract then1 often tear away 

their external surface, making the specimens in1perf~ctly represent the original surface characters. For this reason the molds express the surface characters, both external and internal, 

more accurately than do the shell specimens themselves. 

- E:x:ternal form of shell.-In external fonn the specific characters are the same as the generic 

but are in several particulars fluctuating. Hall remarks that the young forms ''are sometimes 

longer than broad"; in figure 2a he illustrates 2 such a specimen (var. gamma) and in figure 3a 

a young specimen" of the ordinary form"_; this one is broader tlian long (v:ar.' tyzJicalis). The 

specimens from the fauna collected in the· Harford Mills section show great ·fluctuations in the 

proportion of length to width; but no specimen (and there are specimens only 4 millirueters 

in length) shows a form as narr.O'\\~ as that in IIall's figure 2a. . 

Some specimens from Harford Mills (var.· alpha) are n1ore extended laterally at the cardinal 

extremities than are any figured from the I-Iamilton; and some of then1 have sides sloping off 

with un:common abruptness toward the front, giving the shell a subtriangular instead of the 

general normal quadrate form. For example, one specimen (Pl. I, fig. 47) of the I-Iarford Mills 

faunule shows an extension of the hinge margin to 11 millimeters and a. total length of only 

7.3 rniP-imeters; the sides of this specimen slope rapidly together toward the front, so that 

about halfway to the front the width is only 7.8 millimeters. This specimen, which may be 

called Tropidolept1,ts carinatus zeta, is the most extreme form ~own, but others show similar modifications. Another specimen (Pl. II, fig. 24) shows approximately straight sides nearly at right 

angles to the cardinal margin from the front to below the middle; and at the left-hand cardinal 

angle the margin ?f the shell·expands for a millimeter or so in front of the end of the hinge, 

thus combining the characters of vars. typicalis and beta. But this is the only specimen in the 

lot in which the cardinal angle is rounded; in a few the angle may be as great, but in the great 

majority it is less than a right angle, and in a considerable number a broad mucronation appears. 

1 Paleontology: Geol. Survey New York, vol. 4, 1867, Pl. LXII and p. 407. 2 Idem, Pl. LXII. 
I 

GENUS TROPIDOLEPTUS. 

The average form in these respects of the specimens fron1 I-Iarford :Mills is fairly well repre.:. 

sented by figures 3t and 3w of I-Iall's plate 1 of the I-Iamilton types, already referred to as Tropidoleptus carinatus alpha, and quite a respectable minority of the specin1ens have their lateral 

margins appreciably narrower at each successive millimeter fron1 the cardinal angle to the 

front; in the majority, however, the sides are nearly parallel for .about a quarter of the length 

toward the front. This element of form thus shows progressive n1odification toward the new 

variety zeta. The majority of I-Iamilton specimens, so far as I have examined them, hold a subparallel direction of the lateral slopes for approximately the mid-third of length of the shell. 

:Many large specimens round off at the cardinal as well as the front angle of the shell; but they 

rarely show contraction of the lateral margins sufficient to throw the greatest breadth more 

than halfway fro1n the cardinal to the front J?largin. 

Thus, though it is apparent that the samples of the genus contained in zone No. 1 are rela- -

tively narrower in. front and n1ore extended proportionally at the cardinal border than the 

samples fro1n the I-Ian1ilton forn1atio:Q., a rough estimate of the number of specimens in the 

sample (l-Id. 13G, 1r) on each side of the n1ean. developn1ent of the series indicates that the 

amplitude of fluctuation in respect to general form is approximately the same for the Hamilton 

and the zone No. 1. The mean has shifted about one-fifth of the total range of fluctuation 

town.rcl the extren1e represented by Plate I, figure 47 (Tropidoleptus carinatus zeta). No specimens in the zone No. 1 express the extreme rounded .cardinal angle and broad quadrate form 

of the I-Iamilton type Tro1Jidoleptus carinatus typicalis, and, so far as known, no specimens in 

the I-Iamilton attain the broad mucronated cardinal angle and sloping sides of the extr~me 

for1ns of the zone 1 (Tropidoleptus carinatus zeta). Nevertheless the great majority (two-thirds, 

approxi1nately) of the specin1ens from zone .1 correspond in form: with specin1ens observed in 

the I-Ianlliton formation. · 

Pedicle valve.-After critical comparison of the specin1ens of the sample faunule of the zone 

No. 1 with the descriptions and figures of those in the fauna of the Hamilton I do not discover 

any appreciable departure fron1 the described characters of the general form elt:~ments of the · 

pedicle valve. (See Pl. I, figs. 1-27.) . 

Brachial valve.-The brachial valves from the zone No. 1 (Pl. II, figs. 1-24) represent 

very closely the general form of the brachial valve13 described and figured for the I-Iamilton 

specin1ens. In the san1e stratum and grading into this series by imperceptible steps is another 

series (Pl. I, figs. 42-64) showing a departure fron1 the described Hamilton characters in 

respect to the curvature. of the shell. The I-Ian1ilton forn1s vary fron1 nearly flat to broadly 

concave, and in all of thmn flatness begins at an extrmnely early stage of growth. I have failed 

to discover on any I-Iamilton specin1ens an initial convexity of the surface of the brachial valve. 

Nor (except for a few specimens that see1ned to have been crushed) have I observed any I-Ia~nilton specin1ens in which there was a sudden change in the curvature of the shell. · 

The second selected set of brachial valves fron1 the zone 1 (Pl. I, figs. 42-64), however, 

shows both an initial convexity and a natural geniculation, ~he angle of the bend facing inward 

and increasing the convexity of the shell. Several specimens (Pl. I, figs. 42, 43, 48, 55) show distinct initial convexity/ though in these the convex part does not exceed a milfuneter in length 

and beyond this the surface is flat. In one specin1en (Pl. I, fig. 42) the convex- part extends 

about 2! 1nillllneters fron1 the apex. In another (Pl. I, fig.· 44) it extends 4! 1nillin1eters, 

approxi1nately the whole length' of the shell. In still. another specin1en (Pl. I, fig. 64) it is flat 

for about the same distance and then bends outward. In n1ost all the shells in this set (Pl. I, 

figs. 42-64) a n1ore rapid curvature outward begins within~ or 4 n1illimeters from the apex. In 

one spec·imen (Pl. I, fig. 64) the geniculation is seen :41 its typical condition; for 4 n1illimeters 

fron1 the apex of growth toward the front the surface is appr9ximately flat; within the next 3 

nlillimeters the shell curves abruptly and steeply outward, and for the last 5 millimeters the · 

n1edian plication is approximately straight, though having a slight concavity on the sides. The 

angle between these two nearly flat surfaces is about 120°. This tendency of growth is seen 

1 Paleontology: Gcol. Survey New York, vol. 4, lSGi, Pl. LXII. 

2 It must be borne in mind that all the specimens illustrated are molds of exteriors, and that convexity in the specimen is shown as concavity 

in tho molds. 
40 RECURRENT TROPIDOLEPTUS ZONES IN NEW YORK, 

in a less degree on nearly all the specimens of this set, though not so strongly n1arked as in 

the specimen cited (Pl. I, fig. 64). It is evidently associated with the narrowing of the lateral 

nlargins of the shell already referred to as characteristic of variety zeta and expresses a modification in the general form, not affecting all but showing to some degree on half of the specimens of 

this sample lot. Taking all the specimens of the lot together, I consider the character here 

mdicated as a fluctuating variation in n1ode of growth. So far as my examination has extended, 

although Hamilton forms show fluctuation in the degree of concavity of the brachial valve1 the 

normal is nearly flat and the peculiar geniculation is not expressed. Further search may reveal it, , 

however. As an indication of evolution it is evident that there is increasing frequency and fuller 

expression of this moClification in zone No. 1 than in the Hamilton. Here, as before, however 

(p. 37), the advance sl).own by comparison of the. shell in the two stages of its history is but a 

fraction of the total range of fluctuation shown by the individuals of this single sample of 

the fauna found associated together in a space of a square foot or so of rock. 

Surface characters.-In his description of the Hamilton species I-Iall stated 1 that the simple 

rounded plications are "wider than the spaces between them." Examination of the surface 

form inclines me· to think this difference is more apparent than real. The corrugations appear 

to be quite regular, the depression and elevation taking place at the same rate and making 

furrows quite uniform with the plications. The smoothness of the surface does give the effect 

of a sharp change from the illuminated plication to the trough of the dark depressed surface. 

The edge, of the shadow if taken for the edge of the plication gives the effect, when the shell is 

held in certain angles to. the light, of a narrow trough. llowever the character n1ay be defined) 

I discover no appreciable difference in the width of plications between shells from the 

Hamilton· and those from zone No. 1. · 

In number, however, the plications fluctuate, as was recognized by Hall in his description 

of the Hamilton forn1. 1 In Hall's figures the number of observed plications runs as follows: 

18, 20, 19, 18 (Pl. LXII, fig. "3d"=4), 32, 26, 17, 19, 21, 20,21 (fig. 31 after mid-growth shows 

a splitting and thus doubling of the number of plications), 19, 16, 1~, and 18. 

Fifteen plications to the shell is the least number expressed by the figures, and 18 to 20 

appears to be the normal number. This may be more precisely defined by saying that san1ples 

of the pedicle valve from the llamilton ex:p.ibit on the surface 8 to 10 plications on each side of 

the median plication. The fluctuation is chiefly clue to greater or less distinctness of the plications 

at the cardinal angle of the shell. A triangular space on the cardino-lateral angle of the shell 

is smooth. In shells in which the plications are greater in numb_er than the normal the 

additional plications are very faint and small and appear oil the edge of this smooth area. In 

shells in which the plications are below the normal number the smooth surface is broadened. 

It is therefore a fluctuation as to the extent of surface affected by the corrugating process. 

Examination of the samples of the zone No. 1 from Harford Mills shows the following 

number of plications: 17, 13, 16, 18, 14, 14, 16, 17, If), 16, 19, 18, 15, ~6, 20, 17, 18, 17, 17, 

15, 1.6, 22, 17, 17, 17, 16, 17, 21, 18, 22. This series expresses an amplitude of fluctuation 

from 6 to 11 plications each side the median plication. This fluctuation covers the same n1ean 

as expressed 'by the Hamilton samples figured. There are, however, specimens from the Hamilton showing ·a greater number of plications (32 and 26), and I think that search in the Hamilton 

may show specimens with fewer plications. 

The size of the shells of the zone No. 1 samples is noticeably less than the average size of 

the Hamilton figured samples. Nevertheless, a n1ajority of specimens from the zone No. 1 

show as many plications as do a majority of the specimens from the Hamilton. Moreover, the 

actual size of the plications for a width. of six plications on each side of the center does not 

differ appreciably in the samples. from the two stages. Nevertheless,_ the size of the plications 

does fluctuate. One specimen (Pl. I, fig. 17) has nine plications in a distance of 9 millimeters, 

horizontally, across the middle of the shell; another specimen (fig. 18) has about 10! plications 

in the same distance; and a third (Pl. I, fig. 26) shows 12. 

1 Paleontology: Geol. Survey New York, vol. 4, 1867, p. 407. 
GENUS TROPIDOLEPTUS. 41 

The fluctuation expressed by these measurements is associated with relative width of 

muscular scars and teeth plates; the size of the plications over the center of the shell also . 

fluctuates correspondingly. This same kind of fluctuation is expressed· in specimens from 

the I-Iamilton. It is evidently associated with the particular stage in the growth of the individual 

at which the rate of growth was accelerated, and thus reflects individual response to conditions 

of environment. These differences in individual expression of growth rate are found in any set of 

sample~ and, so long (in the history of the race) as they show no signs of restriction, they are 

evidence of the continuity of racial characteristics. They should not, therefore, be selected 

as ground for specific distinction unless it is evident that they are around a new n1ode and, in 

the present case, I fail to discover any such change :ln the mode. The _specimens.of the zone 

No. 1 are, as above remarked, on the average, small compared with the typical IIamilton 

specimens, and I fail to discover any connection between size and the number of plications, 

except in so far as the minuteness of size makes it difficult to observe the extremely slight plications at the outer edge of the shells. Comparing small specimens with the corresponding initial 

part of larger shells there appears to be very close uniforinity in the production of the plications. 

The enlargen1ent of the central plication is a feature of the recurrent specimens as of the 

I-Iamilton species, and the occasional slight degree of enlargement is alike in both. 

I find no specimen in the samples from the zone No. 1 that shows the bifurcation of plications 

figured by I-Iall in one specimen (Pl. LXII, fig. 31)/_ here called Tropidoleptus carinatus epsilon. 

From the figure this appears to be n;wre of the nature of an accidental sport than a characteristic 

of a normal individual; and if it were to recur it would not stand for specilic mutation unless 

repeated. 

The variation expressed by the author of the species in the statement that specin1ens fro1n 

son1e localities show no appreciable ''difference in size of the costre" evidently refers to a lack 

of the special enlargement of the central plication noticed in most specimens. This variation 

is paralleled in the series of the zone No. 1 by numerous specimens (Pl. I, figs. 18, 26, 54, 64; 

and Pl. II, figs. 4, 24) and shows that this feature has remained in a fluctuating state in the 

descendants of 'the I-Iamilton species. 

The concentric, fine lines crossing the plications, and the stronger imbrications are as 

conspicuous in the specimens from the zone No. 1 a~ in the .Hamilton specimens. 

Oonclusions.;-Thus, after critical .comparison of all the characters selected by I-Iall as 

expressive of the IIamilton form, it is evident that there is not a single one of them which was 

not fluctuating in the I-Iamilton .. The majority of characters used in defining the IIamilton 

species are in the same state of fluctuation in the zone No. 1. Roughly expressed, about four-= 

' fifths of the specimens in the zone No. 1 are strictly within the range of fluctuation observed in 

the typical I-Iamilton forms. Not more than one-fifth transgress the normal amplitude of 

fluctuation. These facts seem fully to authorize the conclusion that the representatives of the 

genus Tropidoleptus in the zone No. 1 are in direct genetic relationship with the Hamilton 

representatives, and that the race has not been modified in its long history sufficiently to remove 

it fro1n the specific linuts of the Ha:nlllton species Tropidoleptus carinatus (Conrad). 

STATUS OF FLUCTUATING CHARACTERS IN ZONES NOS. 2 AND 3. 

Specimens examined.-The facts bearing on the specific identity of the representatives from 

the zones Nos. 2 and 3 correspond to those already arrayed from the zone No. 1. The collections 

have all been closely examined, but few of them· comprise sufficient specimens to warrant 

detailed consideration, for· a small faunule expresses only the particular variations among 

accidentally selected specimens and furnishes small ground f~r ~stimating their .av~rage or range. 

From the zone No.3, at top of the Cayuta member of the Chemung, in Spencer Lake ravine (Wv. 

1A, 1 vvv), a fine series was obtained from which may be gathered some idea of the morphologic 

expression .of the genus at its highest known range. Seventy-five specimens were ·prepared 

and mounted on tablets for study-all of them molds of exterior or interior surfaces. 

1 Paleontology: Geol. Survey New York, vol. 4, 1867, p. 407. 
42 RECURRENT TROPIDOLEPTUS ZONES IN NEW YORK. 

Externalform.-The specimens attain greater size than any in the Harford Mills section. 

Ohe specimen is 24 millimeters and half a dozen are 20 millimeters or more in width. The 

widest specimen from the Harford Mills section of the zone No. 1 is only 18 millimeters wide, 

and n'ot over half a dozen specimens reach a width of 15 millimeters. In both sets small 

forms are present down to 4 millimeters broad; and several still smaller ones are in the Harford 

Mills set. · 

The samples from the zone No. 3 do not depart to so great an extent from the Hamilton 

specific type as do some specimens from the zone No. 1. - Several specimensshow a cardinal 

length not equal to the greatest width of the shell, and rounded cardinal angles (var. beta) are 

.not common. The variety with angular cardinal wing and sloping sides, contracting forward 

(var. alp~a), is, however, present. The elements of form fluctuate. in the same way as in the 

Hamilton samples; but so far as evidence of the samples goes, the range of fluctuation is greater 

in the specimens from the zone No. 1 than in those of either the Hamilton or the zone No. 3. 

This may be interpreted as indicating that these variations are continuously and purely fluctuations, that is, plastic characters showing no appreciable tendency to settle down into uniformity. 

Plications.-The number of plications reaches a higher average in the samples from the 

zone No: 3 than in those from the zone No~ 1. This may be expressed by stating that the number of specimens. in which the number of plications on each side the median plication exceeds 

eight is greater in th_e zorie No. 3 than in the zone No. 1. One example-the mold of the 

exterior of a brachial valve-shows 26 plications. Another specimen-a pedicle valve-shows 

26 plications also. · These latter numbers do not exceed those observed on ·Hamilton specimens, but they do exceed those on any specimen discovered in the lot from Harford J\1ills. 

This greater number of visible pli.cations does not mean a corresponding diminution of 

size of the plications over the central part of the shell; the increase in number arises from an 

extension of the visible plications slightly farther out on the cardinal wing, which, as already 

stated (p. 40), at its extreme is always flat and without visible wrinkling of the surface. 

Brachial valve.-The rather sudden change in direction of the curvature of the surface 

.of the flat, to concave brachial valve (previously spoken of as geniculation; see var. zeta) 

is observed on the specimens from the zone No. 3, but it is uncommon and is less pronounced 

than in selected examples of the lot from IIarford Mills. Specimens 41, 30, and 31 show the 

nor!Ilal flat ·surface; specimens 43 and 45 show the geniculation; specimen 40 shows ~he initial 

conv~xity with reversal to concave and succeeding flatness of the surface. 1 The feature is well 

expressed in the series from Harford Mills (Pl. I, figs. 42 and 43). These several characters 

of the brachial valve are also expressed by the Hamilton examples. 

Oonclusions.-The above comparisons .of the representatives of Tropidoleptus from the 

Upper Devonian zones in the Portage and Chemung formations with the typical representatives 

of the race in the Hamilton do· not show 'the evolution of any strictly new characters. Every 

particular in which the individual specimens are observed to differ from the typical forms 

of Tropidoleptus carinatus of the Hamilton is at the ut£:10st a slightly accentuated expression 

of a character known to be in a fluctuating state in the Hamilton epoch. The extreme amplitude of the.fluctuations expressed. by the extreme specimens of these later stages is in no observed 

case greater than one-fifth of the fluctuation known to be expres::;ed by I-Iam!lton sa1nples of 

the race. The race, therefore, shows its identity in the several separate zones as clearly by the 

constancy in the amplitude of its fluctuating variations as by the constancy of its more uniformly expressed specific characters. 

GENUS RHIPIDOMELLA. 

OCCURRENCE. 

Spec1mens of the genus Rhipidomella have been detected in 88 of the 1,411 individual 

collections of faunules examined from the Watkins Glen and Catatonk quadrangles. These 

are distributed by 15-minute quadrangles as follows: Apalachin, 2; Dryden, 21; Elmira, 4'; 

.Harford, 33; Ithaca, 3; Owego, 4; Watkins, 0; Waverly, 21. By zones the~e samples are 

1 The numbers in this sentence refer to the numbers on the specimens from locality Wv. lA, lvvv, not figured in the present paper. 
GENUS RHIPIDOMELLA. 43 

distributed as follows: Zone of the Ithaca n1ember, 1; zone No. 1, 59; zone No. 2, 10; zone 

No. 3, 18. 

The faunules listed above are the individual local collections made and recorded in the field. 

When these collections were studied in the laboratory the separate lots from contiguous strata 

found to conta:in the same fauna w~re for individual sections combined and treated as a single 

faunule, reducing the nun1ber of samples frorn 88 to the 42 sample faunules containing Rhipidomella as recorded in the table ouposite page 32. 

SCOPE OF INVESTIGATION. 

On account of the considerable range of fluctuation in the characters expressed by the 

shells of Rhipidomella, the genus was selected for exact measurement in order to test the actual 

genetic relationship among its representatives in the several successive zones, and also in order 

to discover, if possible, the law of evolution which such. a genus might express when examined 

critically at several successive points in its history. 

The results of this investigation proved of such deep interest, biologically, that I wrote a 

special statement of the facts under the title "On the persistence of fluctuating variation ill us- _ 

tratecl by the fossil genus Rhipidomella" and read it before the December (1909) meeting of the 

Paleontological Rociety. 1 In this place I will only repeat the facts then developed that bear 

directly on. the discussion of the recurrence of the Hamilton fauna, many of the more interesting details being not particularly pertinent to the present discussion. 

The evidence obtained from the study of Rhipidomella bears on the problems of recurrence in· two ways: (1) It signifies a genetic relationship between the representatives of the 

genus at the separate stages in its life history represented in the several successive recurrent 

zones; and (2) it bears evidence of the integrity of the fauna during the long period of time 

represented and thus throws light on the actual migrations back and forth of the fauna whose 

continuity is thus established. 

SELECTION OF SPECIMENS. 

For the purpose of the special investigation, I gathered a series of· samples of the genus 

Rhipidomella as expressed in five stages of its history, collecting alJ of them from outcrops in 

central New York, within 50 miles of the city of Ithaca, from (1) The Hamilton formation; (2) 

the recurrent zone in the Ithaca shale member of the Portage formation; (3) the recurrent 

zone No. 1, in the Enfielci shale rnember of the Portage formation; (4) the rec~rrent zone No. 

2, .in the Cayuta shale 1nember of the_Chemung fonnation; (5) the recurrent zone No.3, at the 

top of the Cayuta shale 1nember of the Chmnung formation. Twenty specimen.s were obtained 

frmn one locality of the I-Iamilton for1nation; 24 from two localities in the Ithaca member; 

115 fron1 seventeen localities in the zone No. 1; 40 from six localities in the zone No. 2; and 

76 from nine localities in the zone No. 3. 

To cmnplete the series I added some good representatives from the Hamilton formation 

and frmn the Ithaca men1ber of the Portage formation that were contained· in the Cornell 

University collections. These, with the more complete series in the United States Geological 

Survey collection, selected from the special collections of theW atkins Glen and Catatonk quadrangles, constitute 35· sample sets. Altogether these sets contain 275 specimens in sufficiently 

perfect preservation to furnish exact 1neasurements of several different elements of fonn which 

are capable of 1ninute cmnparison with each other. 

MEASUREMENT OF SPECil\~ENS. 

CHARACTERS SELECTED. 

These 275 specimens were carefully prepared, mounted on tablets, and numbered. l\1easurements were 1nade with vernier calipers reading to 0.1 millimeter. 

The following characters were subjected to measurement: L, the length of the shell from 

tnnbonal apex to 1niddle of front margin; W, the width of the shell at the point of its greatest 

width at right angles to the line of length measurement; L', the length of the muscular scar of 

the interior of the pedicle valve; and vV', the width of the n1uscular scar of the pedicle valve. 

1 Bull. Gcol. Soc. America, vol. 21, 1910, pp. 295-312. 
44 RECURRENT TROPIDOLEPTUS ZONES IN NEvV YORK .. 

These four characters were chosen as offering the most satisfactory mathematical expression of the individual form elements of the shell capable of reduction to a common acale; and in· 

making the measurements it was noticed that they do give a fair expression of the individual 

differences among the specimens compared. · · · 

RATIO INDEXES. 

The samples ft01n each lot differ considerably in actual size, owing to differences in the 

individual growth of the specimens when they were buried; and in order to eliminate these 

differences three ratio indexes were derived from the combination of measure~ents to express 

· on the same scale the form characteristics of the specimens. These ratio indexes I rP.presented 

by the symbols Rt, R2, and R3 • 

R1 is the ratio index of the shape of the snell_; that is, it is the proportionate width of the shell 

wnen the length is considered to be 100. It is obtained by dividing the width by the length 

and multiplying by 100. . 

· R2 is the ratio index for the size of the muscular scar of the pedicle valve; that is, it is the 

proportionate length of the muscular scar when the length of the shell is made 100. 

R3 is the ratio. index for the shape of the muscular scar of the pedicle valve; that is, it is 

the proportionate width of the muscular scar when the length of the scar is made ~00. 

In discussing the characters of Spirifer marcyi (see p. 58) I applied the method used by 

Gosselet in measuring SpiTifer verneuili, giving to the ratio index for each dimension a small 

letter instead of R1 , R2

, R3, etc. Thus, using L to indicate length in millimeters, 1 =the index 

value 100 for length; width in millimeters is marked W_ and its ratio index w~ ~ = 1'6o. The 

explanation of the method of obtaining the ratio values is -given in detail on pages 56-58. The 

method is an improvement on that above used, but the latter is retained here because it was 

used in the original publication of the facts. · 

EIHAPE OF SHELL (EXPRESSED BY INDEX R 1.) 

From the shape of the shell as expressed by the ratio index R1 I find great differences 

·among the individual specimens. The extreme difference in the value of the ratio index R1 

for the 275 specimen.s measured is 74.4 (147.8~73.4), both of the extreme forms being found 

in the faunules of th~ zone No. 1. 

The average value of R1 for the 20 specimens (picked out of a large series of specimens from 

a single locality in the IIamilton, without.consideration of specific values, for the purpose of 

getting an average expression of the fluctuation of form in the Hamilton) is 111.9. 

The average value of R1 for the. type figures used by Hall in illustrating the five species 

described bv him from the Hamilton formation in New York State is 111.04. 

, The av~rage value of R1 for the total 275 specimens from the five zones (Hamilton formation, Ithaca member, recurrent zone No. 1, zone No. 2, and zone No. 3) is 108.2. 

· The average values of R1 for the specimens from each of the zones are: Hamilton forma-· 

.. tion, 111.9; Ithaca shale member, 108; zone No: 1, 109.3; zone No. 2, 105.6; and zone No. 

3, 108.6. The extreme difference between ·the smallest and greatest average value by zones 

is 6.3, and the extreme difference between the smallest and greatest average·value ·by species 

in the Hamilton; as figured, is 6.1. · These facts when tabulated appear as follows: 

Average of values of R 1• 

The whole series of 275 specimens ........................................................ 108. 2. 

20 specimens from the Hamilton formation ................................................ Ill. 9' 

Type figures of (Hamilton)-

Rhipidomella leucosia ................................................................... J07. 7 

R. vanuxemi ....... · ...................... : ........... · ............................. 109.·4 

R. idoneus ....... :. . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... . . . . . . . . . . . . . . . . . . . . . . ... . . . . . . . . . . 110. 4 

R. penelope ............................................................ · ............ 113. 8 

R. cyclas .................... , ................................. _. .................... 113. 9 

All species ..........................................................................• 111. 04 

21specimens from the Ithaca member ................ · .................................... 108.1 

115 specimens from the zone No.1. ............................. _-_ ........... · .......... :. 109.3 

40 specimens from the zone No. 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105. 6 

79 specimens from the'zone No.3 .................... ~ ........... -"~ ...................... -108. 6 
GENUS RHIPIDOMELLA. 45 

From this 'table it is evident that the average shape of the shell differs by less than 10 per 

cent by whichever of the above 12 methods the specimens are grouped. The smallest average 

(105.6) is that of the 40 specimens fr01n the zone No. 2. The largest average (1.13.9) is that 

for the species R. cyclas, and the difference between these extrmne averages is 8.3. The averages for the several type figures range fro1n 107.7 (Rhipidomella leucosia) to 113.9 (R. cyclas), 

showing a· differ(lnce of 6.2. 

In other ·words the greatest difference expressed by the average valu.es estimated by stages 

and by sequence in time exceeds the difference expressed by the average of ·recognized species 

of the I-Ianlilton by only 2.2 per cent of the length of the shell. 

To appreciate the in1portance of the above statement it i.s necessary to bring out the anlplitude of fluctuation expressed by the speci1nens in each group, as follows: 

Number 

or specimens. 

A~nplitude of.fluctuation i~1 the val·ue of R1• 

275 ~l'ho wholo series ................................................... ." .................................. . 20 ]JfL!nilton formation .................................................................................. . 

'I'YP{i.~f~\~o~ ~~~\~t:l~~~~~~~)~- ................................. · ....................................... . }t ~r~~~~~~~l~: : ::::: : : :: : : : : : : : : :: : : : : : : : : : : :: : : : : :: :: : : : : : : : : : : : : : :~ :: : : : : : : : :: : : :: : : : : : : : : : : : : : : : 

It ~~~~~~~~ :::: : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : :: : : :: :: : : : : : : : : : : : : : : : : : : : : :: :: :: : : : : : : : : : : : : : All species ....................................................................................... . 21 Ithaca nJClnber .................................................... : .................................. . 115 Zone No. 1 ........................................................................................... . 40 Zone No. 2 ........................................................................................... . 70 Zone No.3 ........................................................................................... . 

Least. 

73.4 

104.5 

103.5 

107 

107 

106.7 

110.8 

103.5 

99.2 

73.4 

91 

91.3 

Greatest. .t~~~cfol.i-

----

147.8 74.4 118.2 13.7 

112 8.5 111.8 4.8 113.8 6.8 121 14.3 117.1 6.3 121 16.5 125.5 26:3 147.8 74.4 119.5 28.5 137.3 46 

Frmn this table it appears that the difference expressed by the averages i~ smaller than 

the actual differences expressed by individuals arranged on any other basis than that of the artificial selection by which the species are defined.· ·There are only three of the selected specinlens representing the artificial specific groups of the specimens fro1n the I-Iamilton for which 

the mnplitude of fluctuation of the value of R1 is not greater than the extreme difference 

between the average values. Moreover, when the five species are "arranged in the order of the 

values of the ratio index R1 (see table, p. 44) i.t appears that none of the successive differences 

is greater than four poin_ts and that ·only one of them is greater than two points: The least 

difference in amplitude of fluctuation (see table above) is 4.8, and the least amount of lapping 

of one species over the next in order is 4.8. Expressed in another way, the fluctuation in the 

set of type figures showing the greatest degree of uniformity in respect to this index is greater 

than the difference in value between any two of the artificial species defined. · 

Exa1ni.ning again the type series of specific figures I find that the extreme difference in 

fluctuation an1ong the five species into which I-Ia\1 divided the Rhipidomella race in the I-Iamilton 

is 6.2 (Rhipiclomella leucosia having R1 = 107.7 and Rhipidomella cyclas R1 = 113.9). (See t~ble, 

p. 44.) If, now, the average value of this index by zones (that is, by successive stages in the 

history of the race) be taken, the extreme difference between the average mode for the severnJ zones is 6.3, the greatest value being that for all the I-Iamilton types (111.9) and the 

least value that for the set of zone No.2 (105.6), zone No. 3 showing a slight increase (to R1 = 

108.6). Thus it appears that the total an1ount of deviation (6.3) in the 1node of this fluctuat-

, ing character.frOin the I-Iamilton to the zone No. 2 is but one-tenth of 1 per cent greater than 

the actual deviation (6.:2) between t).1e extreme specific groups in the I-Iamilton. In the specimens of the recurrent zone No.3 this difference (111.9-108.6=3.3) is reduced to little over 

half the difference expressed in the I-Iamilton representatives of the genus. 

The phylogenetic change in value in the mode of this fluctuating character is in the general 

direction of clinrinishing the mathematical value of the index R1 • This means that the form 

0f the shell is narrowing. A study of the op.togeny of the shells (comparison of embryonic with 

adult forms) shows that, in normal growth of the individual, the direction of change is the 

same, the ratio index R1 being greater for the young than for the ·adult forn1 of the same shell. 

Also, c01nparison. of the characteristics of the Silurian species of the genus with those of the 
46 RECURRENT TROPIDOLEPTUS ZONES IN NEW YORK. 

Carboniferous species shows a similar trend in the forn1 of the shell in the phylogeny, or life 

history of the race. This fact is exhibited by comparing the values of R1 in two characteristic 

Silurian species with its values in two characteristic Carboniferous species. In Rhipidomella 

circulus (Clinton formation) R1 = 117 .3, and in Rhipidomella hybrida (Niagara group) R1 = 116, 

an average of 116.6 for the Silurian. In Rhipidomella pecosi (Marcou) R1 = 86.2, and in 

Rhipidomella penniana (Derby) R1 = 87 .5, an average of 86.8 for the Carboniferous. 

The deviation in. mode expressed by these two types at the earliest and latest stages 'in 

the life history of Rhipidomella is 116.6-86.8=29.8. Or, expressed in terms of RI, the change 

in form expressed by the race during its known life history from the Silurian to the Pennsylvanian series of the Carboniferous is approximately 30 per cent in the same direction, as indi-

. cated by growth stages in the ontogeny of the individuaL About one-fifth of this deviation i1). 

mode is expressed by the series from the Hamilton to the Chemung. This total movement of 

the nwde of fluctuation is, however, doubled by individual specimens in zone_N o. 1; it is exceeded 

by individuals from zone No. 3; it is nearly equaled by specimens from both the zones of the 

Ithaca member and zone No. 2; and half of it is expressed by 20 specimens from a single locality 

in the Hamilton. 

SIZE OF MUSCULAR SCAR OF PEDICLE VALVE (EXPRESSED BY INDEX R2). 

The statistics of ratio index R2 are based on the measuren1ent of 142 specimens showing 

the muscular scar on the interior of the pedicle valve. 

The average values of R2 for specimens from each of the five stages are: Hamilton formation, 

60.7; Ithaca shale member not represented; zone No. 1, 64.8; zone No.2, 63.2; zone No.3, 

64.7; all stages, 64.1. 

To judge these figures correctly, it is in1portant to consider the amplitude of fluctuation 

of R2 for the several lot~: 

Amplitude in ~he val1ie of R2 by zones. 

Number 

of specimens. 

Stage. Least. Greatest. ...\~J~:-

------l----------------------------------------------------------1---------------- 12 Hamilton formation ..................... :............................................................. 47 71 

48 ZoneNo.1 ............ ···················································'····························· 57 82 

~g ~~~: ~ ~: ~: : ::: : : : : : : : : : : :: : : : :-:-: : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : ·: : : : : : : : : : : : : : : : : : : : : : : : : : : ~~ ~~ Type figures of (Hamilton): 1 

2 Rhipidomella leucosia. ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69. 2 83. 9 

~ ~: ~;~~~~~i::::::::::::::::::::::::::::::::::::: :.:::::::::::::::::: :':.:::::::::::::::::::::::::::: ~~: ~ ¥!: ~ 

~~ti~o~~r~:r8~F!i~~~~:r:~~ ~~~:l~~~::::::::::::::::::::::::::: :::::::: :_::::::::::: ::::::::::::::::: :::::::::: :::::::::: 

Comparison of the figures in the table above demonstrates that: 

24 

25 

16 

26. 

1 14. 7. 14.8 

5.6 

56 

63.3 

70 

1. The difference in average value of R2 for a typical. Silurian species (R. hybrida) and a 

typical_Carboniferous species (R. penniana) is 14 (70 -56), R2 being smaller by 14 per cent for 

the Silurian than for the Carboniferous species. 

2. The average value (64.1) of R2 for the Devonian representatives of the genus is intermediate between its-values for the Silurian and Carboniferous specin1ens. 

3 .. The range of fluctuation in the value of R2 in each and every sample zone exceeds the 

total difference between the average values of the Silurian and Carboniferous type~?. · 

4. In only one Hamilton species (Rhipidomella vanuxemi) is the fluctuation shown in the 

type figures less than the total difference -between the smallest Silurian and greatest Carboniferous extremes. 

5. Tl~e difference between the proportionate sizes of the average muscular scars of the 

samples from each zone (64.8-- 60.7 = 4.1), is less than th~t expressed by two selected type 

specimens of the species R. vanuxemi which by the author of the species is recognized as showing 

the least fluctuation in this character of all the species of the Hamilton. Each of the other 

species for which selected figures are given, R. leucosia and R. penelope, show a difference three 

times as great. 
GENUS RHIPIDOMELLA. 47 

I-Im·e again the laws expressed by the index R1 are found to prevail. Th~ fluctuation in 

the value of R2 for the genus throughout the successive stages in its life history represented in 

the recurrent zones is less than the fluctuation recognized as legitimate within each artificial 

specific group in the Hamilton; its value is intermediate between Silurian and Carboniferous · 

types; and the general trend of its modification coincides with that expressed in the evolution 

of the race in general. 

SHAPE OF MUSCULAR SCAR OF ~EDICLE VALVE (EXPRESSED BY INDEX R3), 

The fluctuation in the shape of the muscular scar is much greater and n1ore irregular than 

is that of the other characters here dealt with. 

There are in evidence 142 specimens. The range of difference in the value of R3 is from 

75 to 127, a difference of 52 points. The average in all sets is within a few points of 100; but 

the individual specimens differ widely. The type figures of R. vanuxemi differ irt value of R3 

from 65 to 108.2, or 43.2 points; the three of R·. penelope differ less-by only 7 points (101-108); 

and the two of R. leucosia differ by only 2 points (87 -85). · 

The range in. value of R3 for specimens by zones follows: 

Number 

of specimens. 

l].ange of R3 by zones. 

Stage. Least. G rca test. Range. 

--~-1---------------------------------------------------------l----------------

13 Hamilton fonnat.ion .................................................................................. . 42 Zone No.1 ........................................................................................... . 24 Zone No.2 .................................................. .' ........................................ . 57 Zone No.3 ........................................................................................... . 

89 

75 

76 

85 

110 

114 

127 

116 

, 21 

39 

51 

31 

These values of index R3 are, however, too widely scattered to give them much value in 

generalizing. Each sample set shows considerable fluctuation; almost every set, including 

two or more specimens, shows as much as 10 points deviation; almost every set of _half a dozen 

specimens reaches 20 points; and in only a few faunules are any two of the specimens less than 

a full unit apart. The statistics, therefore, of this factor are too scanty to permit any conclusion 

other than that the fluctuation in the value of R3 is great and shows no definite tendency to 

gather into separate specific groups. 

· · The available type figures of the three described Hamilton species show that the muscular 

scar ratios (R3) of two of the types of R. leucosia and one of the types of R·. vanuxemi differ by 

6 points;_ the other types of R. vanuxemi and two of the three types of R. penelope differ by 

2 points; and the two types of R. vanuxemi differ by 18 points. It follows that if the type 

figures represent real specific groups this character fluctuates to three times as great an amount 

within the species of R. vanuxemi as either of the other species fluctuates away from R. vanuxemi. 

Oonclusions.-The evidence thus derived from a millute examinatl.on of the characters 

expressed by representatives of the genus in the recurrent faunal zones confirms the general 

hypothesis above stated regarding these faunas-( I) that a genetic relation exists in the several 

zones among ~he representatives of each repeated genus; and (2) that the faunas to which they 

belong do recur, and that migration did take place outward from and back again into this area 

at the three stages expressed by the recurrent zones Nos. 1, 2, and 3. 

SPECIFIO DISCRIMINATION OF RHIPIDOMELLA. 

ARTIFICIALITY OF PRESENT DISTINCTIONS. 

The specimens figured on Plate III (mostly the interior molds of pedicle valves). furnish a 

series of forms which differ in almost every detail but which, nevertheless, when taken in 

connection with their associates in the same faunules at differ.ent geologic horizons, impresd 

me, and I think must impress every observant paleontologist, as being closely genetically 

related in the I-Iamilton and in each of the recurrent stages in the Upper Devonian. 

The forms are so conspicuousl_y different, no two being strictly alike, that at first one might 

·regard each as representing a separate species, or at least a separate variety. But after· a 
48 RECURRENT TROPIDOLEPTUS ZONES IN NEW YORK. 

thorough study of ·"the whole series of which these are a few samples, one becomes convinced 

that they are all intimately related genetically and that throughout their history they never 

break up into pure lines or "genotypes," but maintain throughout a blending of strains expressed 

in constant fluctuation of particular characters. Investigation shows that the characters by 

which Hall differentiated the Hamilton species are so constantly fluctuating in every set of 

specimens, whether selected on a basis of fauna, formation, or stage, that they can not be 

regarded as an expression of any genetic differentiation of the specimens compared. The elements of form on which the discrimination of the Hamiltonspecies has been chiefly based so 

run together in any large series of specimens that one is compelled to regard the divisions as 

artificial. 

The. form which approaches nearest to the mean of the several fluctuating elements is 

Rhipidomella vanuxemi; the wide form with low beak is R. penelope, if large, and R. cyclas, if 

small; the narrow form with produced beak and extended cardinal slopes, throwing the greatest 

width toward the middle of the shell, is R. leucosia. The characters upon which R. idoneus are 

based are different from those here selected for comparison. These specific terms are useful to 

those who want names by which to classify collections, but they will require stretching to 

enable them to cover all the specimens that will be fouri.d in any good-sized collection from the 

Hamilton or from later rocks. 

POSSm~E MEANS OF DISCRIMINATION. 

On the other hand, any classification based on the relative size, the shape, or the structure 

of the muscular scar of the pedicle valve will necessitate an entirely different distribution of the 

specimens, as may be seen by the figures on Plate III. 

Some of the differences in characters which on theoretical grounds might be supposed to 

be uniform within the same genus are considered below. 

Pedicle area.-The triangular area is exhibited on numerous specimens. In Plate III it 

appears clearly on figures 1, 2, 3, 8, 11, 15, and 18 and its anterior part on figures 13.and 17. 

In size it bears .a fairly uniform relationship to the general muscular platform. Its length is 

evidently directly associated with the elongation of the beak; in narrow forms (such as fig. 11) 

it is longer than in specimens with low umbo (fig. 18). It furnishes, however, small basis for 

differentiating the varieties in this series. 

Hinge teeth.-The size and direction of the hinge teeth is quite uniform in RhipidomelJa; 

the angle they bear to each other is 9oordinate with production of the beak above the cardmal 

margin; and, as the ridges bounding the muscular scar are continuations of" their bases, the 

angle they make with each other is less in specimens (see figs. 3 and 15) in which the scar is 

relatively narrow 'thail in those (see figs.· 13 and 14) in which the ·scar is broad. The sides of 

the muscular platform in the posterior portion are in a general way parallel to the side.s of the 

cardinal slopes of the shell, indicating a general coordination between the muscular scar and 

this form of the shell. 

Median s.eptum.-The specimens figured diff.er considerably in size, width, and longitudinal 

extension of the ridge separating the two main areas of the muscular scar. In figure 1 the 

anterior adductors are set deeper into the shell substance than are the diductors; though the 

posterior adductor is on a slight septum, it is still not raised above the main surface of the 

diductors; the septum extends forward into a slender ridge which is set, in a broad groove. 

In the specimen shown in figure 2 the posterior adductors, though small in size, are in 

depressions of the shell; the median septum begins between them· and extends forward as a 

thin sharp ridge to the front rim of the diductor, where it stops abruptly. In the specimen 

shown in ·figure 3 (also from the I-Iamilton fauna) the anterior as well as the posterior portions 

of the adductors are u,pon a septum the posterior part of which is strong but not wide. In the 

specimens shown in figures 4, 6, 10, 11, 13, 17 two strong ridges start from the outer sides of 

the ant~rior adductors, separating them from the diductors; these ridges meet in front of the 

anterior adductor and form a strong septum which separates the interior lobes of the diductors 

and terminates at their front rim. In figure 11, as in figure 3, and to son1e degree in figure 13, 

the anterior portion of the anterior adductor is shown as elevated on the back of this septum. 
GENUS BHIPIDOMELLA. 49 

In figure 18 (specimen from zone No. 3) the septum is shown to divide the anterior lobes 

of the adductor; though well developed, it is low and broad and shows two slight grooves 

diverging slightly fl:S they pass forward and reacl;ring nearly to the· front of the shell. Figure 7 

(specin1en from zone N.o. 1) shows a similar modification of the septum. 

Muscular scars.-The anterior adductor scars differ markedly in size and form, as will be 

noticed on comparison of figures 2, 4, 6, and 18. The posterior scar may be narrow and simple, 

as in figure 2, or broad and extended forward, as in figures 18 and 7 and to some degree also in 

:figures 1 and 11. 

The diductor scars differ greatly in shape, size, and subdivision into lobes. The fonn 

n1ore frequently found is narrow behind, with nearly straight sides following forward from 

the teeth pln,tes; expa~1ding fan-shape, m;td regularly rounded in front (figs. 1 and 10). This 

forn1 is 1nodified by both the Gontraction of the sides and the elongation of the median lobes. 

The n1edian lobes are generally more strongly depressed in the shell substance, and in many 

shells are elongated beyond the front rim of the general scar, as shown in figures 4 and 13 and 

to an extren1e in figure 2. The subdivision into lobes is also not uniform; in some specimens 

a few strorig lobes are seen (fig. 13); in others the subdivision· is irregular and is not strongly 

marked (figs. 1 and 7). Few lobations are quite symmetrical and some of them (figs. 6 and 15) 

show evidence of abnormal growth. · 

Interior markings.-In several figured shells, and in not a few in the collections examined, 

the n1olds show evidence of ridges that have developed in the substance of the shell and that 

have affected the form of the muscular scars; evidently these are abnorn1al growths. (See figs.· 

8, 6, and13.) 

Dijj'erence in convexity ofvalves.-Normally in specimens of good size from the softer shales 

of western New York the pedicle valve of Rhi'pidomella vanuxemi is n1ore or less convex. I'll 

the 1nore. sanely shales of the I-Iamilton in central New York it is less convex and in some specimens is nearly flat. In son1e of 'the broader forms to which the name R. penelope is applied the 

pedicle valve is slightly concave toward the front. 

The specilnens here figured from the I-Iamilton are slightly convex but not so much as 

are the figured specin1ens of typical R. vanuxemi from the soft n1ud shales of the west. Figures 

10, 13, and 18 show shells slightly concave il1 the front part of the valve; figures 11 and 15 

preserve the convexity to the front. 

The flattenil1g of the pedicle valve with corresponding increase in convexity of the brachial 

valve shown by the two figures 13 and 14 (two sides of the same speci1nen) is characteristic 

of the later recurrent specilnens, showing an accumulating tendency toward that modificatimi. 

The change is slight and gradual and does not affect ~n equal degree all specimens in each 

ascending zone. Nevertheless, an increasil1g numbe1~ of flat or slightly concave forms appear 

in the higher zones, whereas in the Hamilton this modification passes beyond a slight flattenil1g 

of the fL"ont portion of the pedicle valve ohly among wider tu1,d larger forms such as would 

be called R. penelope. · 

Thickening of the shell.-In the successively higher zones an increase in the strength of the 

shell is manifested not only by the actual thiclmess exhibited in molds but in the deeper 

cutting of the mus~tllar inlpression~, the larger teeth, and the absence of the surface lines on 

molds of the interior. These surface lines are seen in the later recurrent specin1ens only at 

the outer rim of the shell (figs. 18 and 7), whereas in the Hamilton specin1ens preserved in 

the same way they are seen over the entil·e surface of the interior outside the muscular scar 

(fig. 2). . 

This feature is also expref:)sed in the rigidity of the shells. Few specimens from the zone 

No. 3 are crushed or flattened, though laterally they may have suffered distortion of form, 

resulting from the movmnents of the rock after their fossilization. :Many of the Hamilton 

and Ithaca forn1s are flattened. (See fig. 5.) · 

The increased thickness of the later shells is accompanied ·in numerous specimens by 

abnornlal deposits of shelly Inatter inside the shells. (See figs. 8 and 13.) vVhether this \ 

67437°-No. 79-13-4 
50 RECURRENT T.ROPIDOLEPTUS ZONES IN NEW YORK. 

apparent tendency to excessive formation of shell substance is an evidence of the evolutional 

old- age of the race, or is an adjustment to a more strenuous environment, or is merely the 

result of the sorting out of the stronger shells by the heavier action of the waves bringing them 

to the state of rest, is difficult to determine. · 

CONCLUSIONS. 

The great vaFiability in all the elements of form of these shells of Rhipidomella~ not only 

in the Hamilton but at each of the recurrent zones in the Upper Devonian, makes me hesitate 

to increase the specific nomenclature by proposing new names for each separate combination~ 

for to do so would require an extraordinary number of divisions, whether they be classed as 

varieties or species. In my opinion they should be held together for the present and for at 

least as much longer as will enable the paleontologist to grasp the idea which has been forced 

upon me as I have studied -them, to wit, that they constitute a series of organisms which 

during their l1fetime were genetically bound together by an indefinite amount of crossing and 

mixing and which in their successive appearances did not lose capacity· to breed together. 

·They show evidence of adjustment' to environment in the fact that many of the sets from· 

separate faunules, taken as a whole, show some local peculiarity of size or shape but yet 

retain flexibility of expression. in the describable characters. Their characters can be satisfactorily expl·ained only by supposing genetic relationship, and so long as all the characters 

by. means of which species can be discriminated continue to fluctuate it seems impossible to 

consider that any of the observed differences have been permanently established. AnCl if 

they are not permanently established (that is, if they remain fluctuating characters) any 

attempt to use them in discriminating zones or stages in .geologic time will lead to unsatisfactory 

results. 

SPIRIFER MARCY!. 

DIFFERENTIATION. 

In the final arrangement of the spirifers as expressed ~ Hall and Clarke's "Paleozoic 

brachiopods" 1 Spirifer marcyi is placed in a large group called "Ostiolati," with Spirifer 

ostiolatus Schlotheim and S. oweni Hall as types. The Ostiolati include spirifers such as S. 

auflaculus., with smooth surface, and S. granulosus, with fine granulose pustules, but exclude 

Spirifer mesistrialis, which is placed in the group "Radiati," of which S. radiatus of the 

Clinton and other Niagaran formations is the type. 

i do not propose here to discuss the merits of such a classification, but I do wish to call 

attention to the fact that, whatever species may be associated with Spirifer marcyi in a general 

subdivision of the genus, the forms recurring in the Upper Devonian, with all their fluctuating 

· variations, are quite distinct from the striated form Spirifer mesistrialis found in the same 

formations but only very rarely associated with Spirifer marcyi in the same faunules; also, that 

all specimens of the recurrent S. marcyi forms, which are sufficiently preserved to show the 

minute surface characters, are marked by pustules and are distinct from the smooth-surfaced 

type of S pirifer audaculus. 

In his definition of the species Hall recognized the decidedly fluctuating expression of 

many of the specific characters of Spirifer marcyi. 2 In tracing it in the recurrent zones ahove 

the Hamilton the rather attenuated pointed beak, the relatively fine plications, the high area, 

and the peculiar surface markings- are the more constant diagnostic features. Its great 

plasticity, however, in many elements of its morphology gives to the specimens of the race, 

as it appears in the Upper Devonian, a variety of expression which seems generic rather than 

specific. In fact, the difference, expressed by representatives _of the race in. single faunules, 

is much greater than the difference expressed in the same faunule by representatives of Rhi~ 

pidomella, which has been distributed into five specific groups in the 'I-Ia.milton epoch of 

its history. · 

1 Paleontology: Geol. Survey New York, vol. 8, pt. 2, 1894, p. 28. · · 

2 Idem, vol. 4, 1867, p .. 226 and Pl. XXXVII. 
SPIRIFER MARCY!. 51 

I-Iall stated in his original description that "in both valves the sprface is marked by very 

fine elongate pustules which become crowded toward the front in old individuals. This gives 

a very n1arked and reHable character when preserved." These pustules furnish a means by 

which Spirifer marcyi may be readily distinguished from any other' species in the Hamilton 

or Upper Devonian.of New York, particularly from the S. audaculus-macronatus group, the 

members of which resemble it in general aspect, .but have smooth surfaces without pustules. 

It is readily distinguished from S. granulosus by its form, by its finer plications, and by its 

rarer and more elongate pu~tules. It· differs· from Spirifer mesistrialis and its close allies in 

several respects, the latter having wider and n1ore flattened plications and a linear arrangement of surface n1arkings; in son1e of the higher representatives of S. mesistrialis the lineations 

appen.r to be inter~·upted but on close examination are found to be in continuous lilies, 

\Vhereas the elongate pustules of S. marcyi are not continuous but are distributed irregula;rly 

and interruptedly in the lo~1gitudinal direction. 

RECURRENCE BY ZONES. 

Spirijer mesistrialis appears abu!}dantly in the Ithaca member of the Portage of the eastern 

part of the Watkins Glen and Catatonk quadrangles; and varieties of the san1e race are abundant 

in the Spirifer disjunctus fauna of the Cayuta n1en1ber of the Chemung and continue to appear 

in the Wellsburg n1en1ber after the disappearance of S. disjunctus. But it is extremely rare to 

frnd Spirijer mesistrialis associated with S. marcyi in the san1e faunule. The few faunules .in 

which the two are gathered togethef are in the Tropidoleptus recurrent zone No. 3, at the top 

of the Cayuta 1nember of the Chemung formation. Below, within a few feet of the recurrent 

zone No.3, as shown in the Spencer Lake ravine section (Wv. 1A), both,Spirifer disjunctus and 

S. mesistrialis are found in great abundance. I conclude that the Spirifer marcyi fauna was 

brought into the area' suddenly and ·in rather full vigo~ at a time when the norn1al Chen1ung 

fauna was present in abpndance, and that it almost but not entirely displaced the latter. The 

extent of the change which took place is shown by the fact that above Tropidoleptus zone No.3 

S1Jirijer disjundu.s is extremely rare, if not entirely wanting; certainly in son1e sections no trace 

of it has been seen above that zone. 

OCCURR.ENCE BY FAUNULES. 

Among the 1,411 separate faunules collected in the area of the Watk.ins Glen and Catatonk 

quadrangles, 79 have shown the presence of Spirifer marcyi. In only 5 of these is the exact 

stratigraphic relationship to the Tropidoleptus recurrent zones in doubt; in the other 74 the 

species is actually associated with other representatives of the recurrent fauna at one of the 

. three recurrent zones (Nos. 1, 2, or 3), or else is within a few feet of such representatives, showing 

the tune separation between the entrance of the two faunas to be not great. The faunules 

that are in doubt lie above the base of the Chemung in the Cayuta n1en1ber. The fossils ·are 

numerous and most of then1 are continually repeated throughout the greater part of the .Cayuta 

memb~r, appearing wherever fossiliferous zones occur. · 

FLUCTUATION IN SUCCESSIVE ZONES. 

DEGREE OF FLUCTUATION. 

0 

The characters expressed by Spirifer marcyi are in several respects fluctuating. Their 

plasticity is indicated in the original definition of the Ilamilton species, which shows their 

amplitude of fluctu~tion to be considerable. It continues to be great in the several recurrent 

·zones, as shown by the specunens examined. These latter offer valuable evidence of mo·dification in time, but can be n1ade to express the· facts only by close observation and minute nleasurement and comparison. 

FLUCTUATION IN ZONES NOS. 1 AND 2. 

The characters of the specimens in the recurrent zone No. 1 are 1i1ore uniform than, and the 

speciJnens do not reach so great size as, those iJ1 the zone No.2. In the zone No. 1 the pustules 

are, in general, n1ore nwnerous than is customary upon flamilton specilnens, but this 1nay be 
52 RECURRENT TROPIDOLEPTUS ZONES IN NEW YORK. 

due in some degree to their smaller size; specimens of more normal type also appear. In the 

zone No.2 the species appears in great abundance in some of the localities and shows considerable 

difference in its surface 1narkings; specimens with the pustules far apart, as in. the Hamilton 

species, are plentiful; others have closely arranged pustules (rarely seen in HamiltP.J?. specimens) 

distributed over the front surface of the 'fold ana sinus. The Tropidoleptus zone No.2 contains 

other specimens in which the surface appears to be aln1ost if not quite free from p~stules; and 

others in which they are very elongate though never strictly continuous in parallel lineations 

like those ,of Spirijer mesistrialis. In this zone the shells also exhibit considerable differences 

in form, size, and relative development of parts; son1e specimens show excessively high area 

with .shortened cardinal margin; others have a high area with the cardinal margin greatly 

extended and mucronate; a lower·flat form is produced by a great extension of the shells laterally . 

. That the specimens indicate great variability of form but belong to a common genetic species 

is shown by the fact that these differences in the lesser details of surface and shape and in what 

n1ay be called the geJferal complexion appear ainong shells taken from the san1e stratum. . 

The interior characters of shells from the zone No. 2 also differ greatly. The strength and 

conformation of the muscular scars, the thickness and extent of the hinge plates, and all the 

morphologic characters expressed about· the umbonalportion of the interior of the shell of the 

pedicle valve show great plasticity. · 

Among the plastic features unmistakable rudiments of the peculiar plates later developed 

as a .syrinx in the. genus Syringothyris ~ppear ori a few specimens. In its earliest forn1 the 

syrinx appears as a pair of low short ridges on the inner face of the cross septunl uniting the 

bottoms of the hinge plates near the apex of the cavity of the umbo. .Comparison with typical 

~pecimens of Syringothyris. shows these ridges to be the same which in Syringothyris develop 

into a tubular extension of the interior called the syrinx. In none of the specin1ens discovered 

by my collectors in· the Watkins Glen and Catatonk quadrangles is this character developed 

beyond the stage of two parallel short plates extending inward fron1 the inside wall of the transverse plate near th~ apex of the umbonal cavity. Its forward ~xtent does not exceed a millimeter and its length from the point of the beak downward toward the center of the caVity·of 

the shell is at greatest not over 3 to j: millimeters. (See Pl. IV, fig. iO.) The ren1arkable fact, 

however, is that a few specimens showing this undoubted rudin1ent of the syrinx appear in 

faunules with specimens which are like therp in other characters but which lack any trace of the 

syrinx~ I examined every one of- the perb.aps 200 specin1ens in the collection, preserving the 

appropriate part of the shell, and found a dozen or so that possess this rudimentary syrinx. 

The character appears in only two or three specimens in a faunule; all the rest show the corresponding parts perfectly sn1ooth. The zone No. 1, as well as the zone No. 2, shows a few specinlens with the rudin1ent, but I have not discovered it on any of the specin1ens fron1 the zone 

No. 3. It is remarkable to fin.d this apparent cessation of the anon1aly, especially as the true 

Syringothyris, stratigraphically, follows in almost direct sequence above the zone No.3; and I 

am inclined to think that its absence is due .to failure to discover it rather than to its actual 

absence from the fauna. Fut11-re investigation will demonstrate the facts. 

FLUCTUATION IN ZONE NO.3. 

Indications of the fluctuations exhibited in the highest Tropidoleptus zone No. 3 by Spirijer 

marcyi ~re noted below: 

Specimens from faunule El. 2G, la, show the pustules on the front part of the sinus. fine 

and close together but somewhat larger, more elongate, and more sparsely distributed on the 

sides of the shell. The form is wide and is not narrowly mucronate. . 

A specimen from fau1iule El. lE is above average size but the sides are not produced 

laterally. On this specimen the punctations, like ··those on the .typical Spirijer marcyi, are 

rather numerous toward the front of the shell. . 

The specimens from faunule Wv. lA, lvvv, are large. Some of the larger specimens have 

the tops of their plications smoothed and flattened, apparently by erosion, and have very faint 

traces of pustules or none; others of' smaller size show the pustules normal. (See Pl. V.) 
SPIRIFER MAH.CYI. 

Large and n1assive pedicle valves are present. No specimens having the slightest trace of the . 

rudin1entary syrinx before' n1entioned. are found in the faunule. The absence of pustules on 

n1any of the specimens gives a frrst impression that they are a modification of Spirifer audaculus 

or macronatus, but the occasional finding of the pustulated surface without other distinctive 

characters of the latter species leads to the conclusion that the smooth specimens have had 

their pustules ren1oved by attrition before fossilization. In a few specimens broad low plications appear in the sinus or on the folds (see Pl. V, fig. 13); other specimens show this rudiInentary development of plications. along the center. The peculiarity of this mode of developnlent is that the plications come over the edge of the fold and sinus frmn outside and are not 

developeel from the center of the fold or sinus like the intercalated plications in Spirijer arenosus 

and S. disjunctus. In the latter species the central plications also are stronger and sharper than 

those near the edges of the fold or sinus. · 

Other faunules of the Tropidoleptus zone No. 3 not only contain specimens in which the 

pustules are elongate but have associated with- then1 specimens with the shape, the wider 

plications, and the linear n1arkings of Spirifer mesistrialis. 

Specin1ens fr01n Ap. liE show typical Spirifer marcyi pustules that vary from the. nor~al, 

elongate, and separate form to one in which they are finer and more closely distributed. 

Specimens 'fron1 Ap. SG, 3, and Ap. 13L have beautifully preserved pustules of Spirifer 

'liutrcyi type. · SUMMARY. 

Comparison of the sa1nples fron1 tho several zones discloses that the representatives of 

the zone No. 2 show the greatest diversities in form and characters; those fr'om the zone No. 3 

show the greatest departure from the· typical characters;' and those fron1 the zone·No. 1 show 

the least diversity and the closest conformity to the type species of 'the Hamilton, except that 

they are conspicuously smaller than the typical Spirifer marcyi of the Hamilton. The series 

offers attractive problems for further research, particularly in regard to thEl origin of the 

characters by which the genus Syringothyris is differentiated. Spirifer marcyi is closely associated with Tropidoleptus and Rhipidomella in the recurrent faunules; its presence in the 

fossil fn.unules is a definite indication of recurrence, and evolutionally it constitutes a continuous line frmn the I-Ia1nilton Spirifer mar:cyi through the Upper Devonian varieties designated 

in the following pages to ~he typical representatives of the Mississippian genus Syringothyris. 

LAWS OF EVOLUTION EXPRESSED BY THE GENS SPIRIFER 1\IAIWYI. 

As so n1uch has been said regarding the general characters of the gens Spirifer marcyi (to 

usc Vaughan's <berin) ,t as it appears in the successive recurrent zones of the Upper Devonian, 

it may be profitable to use the series of forms thus associated to elucidate some of the laws of 

evolution involved. 

EVOLUTION AND CLASSIFICATION. 

The paleontologist in classifying and identifying his fossil specin1ens is liable to overlook 

the evolutional fn.ctor alwn.ys. involved when specin1ens under exa1nination belong to a zone 

below or above that from which came the typical species with which they are compared. 

Although the zoologist may recognize varieties and ((mutations" in the De Vriesian sense, he 

has no call to consider the difference of form to which Waagen applied the term mutation. 

lie includes under the same specific name organic bodi~s of widely diverse form because he has 

been able to trace in actual sequence the changes in form exhibited by the same individual as it 

develops fr01n the embryo to the adult stage. The paleontologist, however, has available only 

the separate individuals represented by their fossilized hard parts, and his application of specific 

names must be based on the likeness of the characters these exhibit. In classifying such fossils 

he is therefore likely to class together only those specimens which agree in their morphologic 

1 A. Vnughan defined "gons" as follows: "A gens or specific group may be considered to be the aggregate <;>fall the species which possess, in 

common, a largo number of essential properties, and are continuously related either in space or time," Quart. Jour.' Geol. Soc., vol. 61, 1905, p. 183. 

~!'his term n.nd conception was later employed by R. G. Carruthers in discussing the evolution of Zaphrentis delanouei, Quart. Jour. Goo!. Soc., 

vol. 66, 1010, p. 523. 
54 RECURRENT TROPIDOLEPTUS ZONES IN NE·w YORK. 

characters and to give separate specific names to specimens which differ in form irrespectiv~ 

of their evolutional or historical relationship to each other. 

It is 'evident, when attention is called to the f·act, that such a method, though of 

practical value ·in labeling specimens for a museum, neglects one of the most important facts 

which the paleontologist alone can dire9tly observe-the evolution of the race. _ 

The n1orphologic development of the individual is so familiar that the fact is apt to be 

forgotten that the so-called specific characters of any particular organism are the characters it 

exhibits ·at its adult stage of development. Paleontologists of the preevolution stage based · 

their nomenclature on such definitions alone. Studies in historical evolution are prevented from 

free progress by this nomenclature, and it. becomes necessary to emphasize the fact that as 

knowledge of the details of paleontologic history increases evidence of progressive modification 

in form of the adult organism should be expected. 

' NOMENCLATURE ADOPTED IN THIS PAPER. 

In the following study of Spirifer marcyi the nomenClature adopted is tentative. It may 

prove satisfactory for general application, or as knowledge along this line develops it may give 

way to some better· method. If it were certain that observed differences in form are expressions 

of actual stages of evolu~ion it might suffice to give them names· indicative of successive stratigraphic zones in geologic sequence. My observations, however, make me uncertain as to 

whether the differences observed are permanently adopted stages of modification· coincident 

with genetic ·evolution or are only temporary adjustments of fluctuating characters to changed 

conditions of environment. 

. In recording the facts, therefore, I here adopt an arbitrary system of nomenclature, which 

may_, be interpreted later (as the further evidence gathered may justify) without prejudice as 

to any particular hypothesis here adopted as to the cause of the modification. 

SPECIFIC IDENTITY. 

In citing among the species of each recurrent fauna of the present paper the same specific 

name I do not mean to convey the impression that the species thus cited has suffered no modification of its characters on passing froin zone to zone.· Where the same specific name has been 

used, I have intended to express the fact that the deflection from, specific characters already 

exhibited by representatives of the species in its typical locality and horizon is not of such a 

nature or amount as to indicate evolution of any new characters not already expressed by 

representatives of the species selected for definition of its specific characters. The use of the 

same name-implies more than that the later specimens are represe.ntatives of the same race as 

the earlier specimens. Modifications have taken place in the race during the long lapse of time 

between the succe'ssive ·stages in its history, and it is only when successive representatives 

express such uniformity of characters as will tie them all together Within the range or amplitude 

of fluctuation of th_eir characters at the first stage examined that they can be assumed to belong 

-to . the same continuous genetic r~ce and can be referred to by the same specific designation. 

If a character appears which is riot discoverable among the fluctuating characters of the earliest 

ex~mined representatives of the group, that character differentiates the specimen under consideration from tlie original group in a specific way; and, although theoretically it n1ay be assumed 

that the· differentiation is a result of evolution within the· genetic series, it is impossible to 

establish the validity of such hypothesis on the evidence; the differentiation may have taken 

place prior to the time represented by the individuals of the first set examined. 

Although such presumable evolution may account for the differentiation exhibited in a 

series of different species appearing in successive geologic beds, such a presumption can not 

stand alone as basis for the establishment of the laws of evolution actually effective in geologic 

time. It is in the discovery of these laws of evolution and their establishment on observed 

fact that I am here interested. 

It should be clearly stated that specific identity does not mean absolute uniformity of 

characters. On the contrary it is well established in all fields of natural history of organisms 
. '~ 

SPIRIFER MARCY!. ' 55 

that no two individuals of the same species a.re absolutely alike in all their characters. The 

critical study of species is leading taxonomists everywhere to realize that the hard· parts of 

organic bodies are not rigidly conformed to mere repetition of the characters exhibited by the 

hard parts of their parents but are expressive ·of a .combination of (1) the hereditary plan of 

construction and (2) its adjustment to the individual experiences of the organism during the 

process of construction. 

The degree of elasticity of application of its hereditary plan of construction is ill each 

individual aln1ost directly proportioned to its vigor. or power to overcome obstacles to its living. 

The more rigidly the hereditary plan of construction is carried out by a growing organism, the 

more certainly will the stress of adv~rse conditions of environment result in the destruction of 

the race. 

I-Ience it follows, as observed in nature, that a certain degree of elasticity in the construction 

of hard parts is common to all organisms. It is also observed that races which show the greatest 

vitality and are represented in geologic history by the longest line of descendants are decidedly 

plastic in the construction of their hard parts-·particularly of those hard parts by which they 

come directly into relationship with the environment; that is, their external covering. 

CRITERIA OF CLASSIFICATION . 

These characters are fluctuating; and, therefore, a species, instead of being defined by the 

characters of the precise form selected as typical by the original describer, should rather be 

defined by the amplitude of its fluctuations under varying conditions of environment. · 

It is proportionate development of parts in relation to some unit of measurement of the 

iridividual itself rather than the divisions of a standard foot rule that must be used in defining 

the cltaracters of a gens which is undergoing evolution of forn1 in successive stages of its existence~ 

To illustrate these and other principles the facts expressed by the forn1 to which Hall applied 

the nmne Spirifer marcyi is a good example. 

HISTORICAL DISCRIMINATION. 

. \ 

S1Jirijer marcyi belongs to that section of the genus Spirifer which has (1) a distinct fold 

and sinus; (2) nu1nerous surface plications (15 or more on each side); (3) a form whose width at 

the hinge margin is 150 to 600 per cent of the length of the middle growth of the brachial valve; 

(4) an area whose height is not less than 25 per cent and may be 50 per cent or more of the · 

length of the brachial valve; and (5) a pustulose surfa~e. All five are positive characters. 

· I-Iall placed the section of Spirijer marcyi in the "group V, Ostiolati" 1 with several other 

sections, all of which may be present in the ·Hamilton in the same stratum. The section, or 

gens, of S1Jirijer marcyi was, in general form and plications, already differentiated in Hamilton 

time by its pustulous surface from the. gens to which S. audaculus belongs, the surface of the 

latter be~ng free from evident pustules. 

The section of Spirifer granulosus differs from S. marcyi in the more intensive growth of 

the 1niddlo part of its valves, producing more gibbous shells; in the overarching beak of its 

pedicle valve; in its '\vider fold and sinus and fewer plications; a:r:d in its generally lower area. 

The pustules of marcyi are scattereg and somewhat elongate; those of granulosus are smaller 

and more crowded and less elongate. The .plications of granulosus bea:r;· to those of marcyi the 

relationship of about si..x to eight in a given distance from the fold or sin1,1s, measured in the 

middle part of the surface of the shell across the plications. The pustules are not uniform on 

either form in the Hamilton; some specimens of granulosus show them sparsely distributed 

over the surface, but most specimens show then1 closely distributed; a few marcyi show them 

minute and closely distributed, but the majority show them sparse and elongate. After the 

I-Iamilton epoch the particular granulosus combination of characters ceases; but the pustules 

of the granulosus type bec01ne 1nore frequently associated with the other marcyi characters. 

1 See Paleontology: Geol. Smvey New York, vol. 8, pt. 2, 1894, p. 28. 
56 RECURR~NT TROPIDOLEPTUS ZONE~ IN NEW YORK. 

The forms called by Hall Spirifer aspera and S. parryana are closely related to S. r.uarcyi; 

but the differentiations expressed by these forms fron1 Iowa signify a separate line of evolution 

from the race in the New ·York Basin r"epresented by Spirifer marcyi. · 

DIFFERENTIATION BY FLUCTUATIN(,l CHARACTERS. 

PEGREE OF FLUCTUATION. 

Organic bodies may be classified in n1any ways, each of which n1ay have particular fitness 

for a particular purpose. In the present discussion the chief purpose is to discover the relation 

of morphologic characters to time and place. If morphologic characters were uniforn1 fo~ a 

large number of individuals of the same place and time, and if their characters differed uniformly 

either at other places or at other times, the ordinary method of applying specific names would 

be satisfactory and useful. . 

But morphologic characters have no such rigidity of expression in nature. They fluctuate not only everywhere but through all time, and these fluctuations seem to affect all the 

hard characters of an organism, such as are alone in evidence in paleontologic series. · 

The so-called taxonomic rank of the characters is more a matter of definition than of 

degree of plasticity. One group of organisms is defined as quadrupeds, another as decapods, 

another as hexapods. The number of .appendages is uniform for a great number of differently 

constructed organisms. The likeness and uniformity _is in the· nu~ber, not in the details, of 

form, and for purposes of classification it is convenient to give higher rank to, those characters 

which are more general in relation to the plan of cpnstruction and to consider as secondary 

characters which are of subordinate relation. 

Whatever the taxonomic rank, however, the morphologic relations of the structures ar~ 

plastic, the degree of plasticity being almost directly coordinate with the influence of the particular structure on th.e vital economy of the organism. Complete rigidity in a structure is in a 

high degree evidence of its small influence in the organic activities of a;n individual; and great 

plasticity among representatives of the same species in the same time ~nd place is evidence of . 

large influence in the same respect. This seems to be a general law in the n1orphology of organic 

bodies. 

This evident correlation between plasticity and organic vigor serves as a guide both in differentiating and in grouping together organisms ·when the chief object in view is to discover by 

means of morphologic characters what influences time and place have exerted in determining 

the particular form of the organisms studied. In classifying the spirifers it is of first importance 

to selecli such characters as express a high degree of plasticity. Thus it is sufficient to select 

only those forms which express the generic characters of the genus and to confine the attention, 

within such a group, to the dif:icovery of. the characters needed to differentiate species within the 

genus. MEASUREMENT OF FLUCTUATIONS. 

Almost all specific characters, however, may b~ defin~d in terms of the degree of their 

development in relation to· the degree --of development of some other particular characters. 

To reduce this fluctuatmg element to mathematical expression is the first necessity. In the 

spirifers the- most conspicuous of these fluctuating characters are the several elements of form 

of the two valves-the length, width, thickness, .cardinal area, curvature of surface, sinus and 

fold, size and number of plications, lines or pustules of s_urface, and so forth. All of these can 

be expressed mathematically by ratios of actual dimensions to ~orne standard unit of measurement· on the individual organism which increases coordinately with individual growth. 

GOSSELET'S METHOD. 

In measuring the characters of Spirifer verneuili Gosselet1 aQ.opted the length of the brachial 

. ' valve, measured from the beak to the front of the shell, as a standard. This dimension, expressed in millimeters,· is adopted as the unit of measurement in the following studies and, 

1 Gosselet, I., Etud~ sur les variations du Spirifer verneuili.· Mem. Soc. geol. Nord, tome 4, pt. 1, 1894. 

' . 

·<. 
SPIRIFER MARCY!. 57. 

whatever its actual diinension, is given the value 100 in determining the percentage ratio for 

other dimensions. It is represented by the symbol L. 

The greatest width of the shell, in n1illini.eters, is represented by the syn1bol W. This 

width in terms of the unit of n1easurmnent is obtained by reducing the actual width in millimeters (W) to a percentage vaJue of the length of the brachial valve; this percentage value 

is represented by the syn1bol R1 or w. 

For instance, in a shell having a brachial valve length of 34 milluneters and a width between 

d. I . . f 'II' W 75 221 h . h. 'd h (W) . car ma extremities o 75 mi 1n1eters: L = 34 =2.21= 100 ; tat Is, t e WIt Is 221 

per cent of the length, and w = 221. q 

The height of the area of the pedicle valve, which is an iinportant element in the morphology of spirifers, n1ay be represented by the syn1bol A, and its percentage value in relation 

· to the length of the shell by R2 or a. If the height of the individual cited above be 5 n1illih A 5 14·

6 

meters, h . h h . h. (A) . f h I t en: L= 34 = .146 = 100 ; t at Is, t e mg t . Is 14.6 per cent o t e ength; and 

a=14.6. 

The value of the thickness of the whole shell with reference to the unit of measurement 

may be obtained in the same way. Let the thiekness be represented by T and its percentage 

value by R3 or t. Then, if the individual cited above has a· total thickness of 31 millimeters: 

t=;!=.91= 1

9

0

1

0; that is, the thickness (T) is 91 per cent of the length (L); and t=91. 

To express the expansion of the fold and sinus let the width in millimeters from side· to 

side at the front margin be designated F and the percentage value R4 or f. If, in the shell cited 

b F 'llim h F 23 67 h . h . (F) . a ove, 1 = 23 nn eters, t en: L = 34 = .67 = 100·; t at Is, t e expansiOn IS 67 per cent of 

the .length, or f = 67. , 

This method of expressing characters by ratios to a unit of measurement provides a set of 

nu1nbers that have exact relation to each other and that show the form of the individual in 

terms which may be mathen1atically compared with those relating to any other individual 

expressed in a sinlilar way irrespective of the actual size of the. specimens.. For the individual 

specimen cited above the elen1ents are: 

Symbol. 

L 

w 

A 

'1' 

p 

Jlfathernatical expression of characters of a partic1dar spirifcr shell. 

Character. 

IJcngth of brachial valve .................... _ .. __ .. __ ...... __ ................................ __ ....... ___ ... . 'Vidth •........................ _ ..................... _ .............. _. _ ...... __ .. __ .... ___ .................. . 

;~~~~~~l;g:s a~{~,~~ ~~-~~~i~l~ho~~~~- ·. ·. ~: : : : : : : : :: : : : :: : :: : : : : : : : : : : : : : : : : : : : : : : : : : : :: : : : : : : : : : : : :: : : : : : : : : : : : : : : : : : 

'Vidth of fold and sinus ..................................... _ ......... _ ..................................... . 

M:illimeters. 

34 

75 

5 

31 

23 

Percentage 

value. 

100 

221(w) 

14. 6(a) 

9l(t) 

6i(f) 

In Gosselet's classification of SzJirifer verneuili six groups were recognized, based on the 

values of the ratio w= 100 ~- The extreme values observed fluctuate between 140 and 400. 

The six groups are: 

Gosse let's scherne of classification of Spirifer verneuili. 

w 

Numerical value of 100 L · 

1. Cylindrici ................................................. 300 and above. 

2. Attenuati................. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250 to 300. 

3. Elongati .................................................... 200 to 250. 

4. Hemicycli ................................................. 160 to 200. 

5. Proquadrati .............................................. Not over 160. 

6. Obovati ................................................... Not over 170 (with greatest width 

below cardinal border). 
58 RECURRENT TROPIDOLEPTUS ZONES IN NEW YORK. 

Gosselet's classes of form are very frequently represented a~ong the spirifers of ·the American Paleozoic rocks, many spE;lcific groups including several of them within ·their range of fluctuation. For instance, each of the common ·New York Devonian species as classified by Hall 1 

has representatives in most of the first five of Gosselet's groups. As furnishing names for 

groups based on a particular range in fluctuation of one set of characters these are useful arbi-

. trary divisions. 

APPLICATION OF GOSSELET'S METHOD TO SPIRIFER MARCYI. 

The species Spirifer marcyi I have found to express. the same fluctuations in form so 

admirably described by Gosselet for the ·species Spirifer verneuili. Spilrifer marcyi, however, 

has other variations which materially affect its external shape: (1) It shows variation in 

height of area and in classifying the species it is important to consider the areal height; (2) in 

some specimens some of its plications dichotomize with the growth of the shell, appearing to 

indicate a tendency to grow toward other species common in the next geologic system; (3) a 

rudimentary syrinx appears on some specimens, though this, with other characters that may 

be found later, may occur without signifying such departure from the general characteristics 

of the species as to call for a supposition that- the evolutional genetic relationship has been 

_ broken. In view of these faqts it has seemed to me appropriate to apply to species showing 

the several combinations of these fluctuating characters an indefinite series of arbitrary names 

(alpha, beta, gamma, delta, etc.) rather than one ·based upon any one of the many fluctuating 

characters of the species. · 

. SPIRIFER MARCYI. TYPICALIS, ALPHA, AND BETA: 

To obtain the primary subdivjsions of the group Spirifer marcyi I n1easured the original 

form to which the name was first applied and gave to it the name Spirifer marcyi typicalis 

(Pl. IV, figs. 1 and 2). Next I took the varietal forms associated with typicalis by the describer 

of the species in fully illustrating his conception of its form, and to two of these,showing decided 

modifications I assigned the names Spirifer marcyi alpha and S. marcyi beta. Later" as new 

forms of the same genus were discovered in. tracing it upward from the Hamilton, I a'dded 

gamma, delta, and so on. . . 

The original description and illustrations .of Spirifer marcyi were published 2 in )857, the 

geologic horizon and locality of the type being "s:Q.ales of the Hamilton group, Covington, Genesee County, N. Y." In the final report (1867) the specimen figured in the first definition of 

the species is apparently refigured. 3 For critical purposes this figured f?rm·is taken as the type 

of the species to which the riame Spirifer marcyj typicalis is here applied. The length (L) of the 

brachial valve of this specimen is 35 millimeters. The specimen is somewhat unsymmetrical; 

the half width on the left side is 34 millimeters,·and on the right side is 30 millimeters as drawn, 

giving !or the shell the total width (W) of 64 millimeters. The areal height of the pedicle valve· 

(A) is 12 millimeters; the width of the .deltidial opening (D) is 12 millimeters. If each of these 

dimensions be expressed in percentage ratios to the length of the brachial valve, the following 

ratio values (indicated by the corresponding -letters) are obtained: 1=100; w=183; a=34; 

and d=34. 

Figure 17 of the same plate shows a. brachial valve,· the dimensions of which are L=33.8 

and W = 75 millimeters, and the ratio values I= 100 and w = 222. 

Figure 15, a pedicle valve, gives, in millimeters, L (estimated) 28; W = 83.5, and A (estimated).= 8. The ratio values are I= 100, w = 298, and a= 28 +. 

Figure 19 appears t9 present similar dimensions to figure 15. 

Figures 10, 11, and 12, which are different views of the same specimen, present 'the following-dimensions, (in millimeters): L~24; W (estimated)=48 (actually 45); A=~O; D=7.5; 

these correspond to l= 100; w (estimated) =224 (actually 211); a=47; d=35. 

1 Paleontology: Geol. Survey New York, vol. 4, 1867; Spirifer mucronata, Pl. XXIV; Spirifer medialis, Pl. XXXVIII; Spirifer mesistrialis, 

Pl.XL. · 

2 Tenth Ann. Rept. Regents New York, 1857, pp. 158 and 159. 

a Paleontology: ~eol. Survey New York, vol. 4, 1867, Pl. XXXVII, fig. 13. 
SPlliiFER MARCY!. 

In these dimensions 1nay be recognized. three forms follo:wing: 

Prim_ary subdivisions of Spirijer marcyi. 

w d 

Spirifcr marcy! typicalis (fig. 13) ....................................................... . Spirifer marcy! a1pha (figs. 15, 17, 19) ...................................... ~-. ~ ........ . 100 200 or less..... 35 or less...... 35 or less. 

100 200 or more... . Less than 35 .. Spirlfor marcy I beta (figs. 10, 11, 12} a ................................................... . 100 200 or more... . More than 35 .. 

a Pl. IV, figs. 3, 4, and 5; and Pl. V, fig. 5, of this paper. 

59 

This f9nn, called Spirifer marcyi in the Hamilton formation, belongs to a series of forms 

which pass, in :r:espect of some of their characters, directly into the species Spirifer granuliferus 

I-Iall = granulosus, as was observed by Hall in the original description of the species. In the 

value of characters here expressed the species S. granulosus fluctuates beyond S. marcyi typicalis 

in the opposite direction from varieties alpha and beta. Spirifer granulosus rarely reaches 175 for 

value of w and rarely over 25 for value of a. Other characters of a positive nature distinguish 

the two species. It is to be further noted that Spirifer granulosus has never been seen among 

the recurrent forms in the Upper Devonian of New York. Spirifer granulosus and S. marcyi 

formed in the IIamilton a continuous series of fluctuating forms, which thereafter became 

specifically distinct; the low area; overarching of the beak; the increase in growth over the 

middle of the shell, both forward and sidewise, producing a swollen central part and a wide 

fold and sinus; and the large1;· and fewer plications are characteristics of the :Middle Devonian 

evolution of the gens expressed in the Hamilton by the typical Spirifer granulosus. The 

increased height of area and its less arched, nearly straight, surface; and the excessive growth 

toward the cardinal extre,mities with less growth in center of shell, giving straighter sides to the 

shell and less lateral expansion of the center part of the shell, and thus incre~sing the number 

of ribs and narrowing the width of the fold and sinus-these are peculiarities of the Upper 

Devonian evolution of the race already expressed in the Hamilton by the gens Spirifer marcyi. 

The nonpustulose gens of Spirffer audaculus-'lrUicronatus-angustus passed through this stage of 

evolution during Hamilton time, and probably ended its existence with the close of Middle 

Devonian. 

It is significant (tying together the granulosus with the marcyi sections of the race) to note 

the discovery of the rudimentary syrinx in a form of the variety Spirifer granulosus clintoni of 

the IImnilton. (See Pl. V, fig. 4.) In the recurrent S. marcyi of the Upper Devonian .this 

character is frequently seen / 

SPIRIFER 1\IARCYI GAMMA. 

In the Tropidoleptus recurrent zone No. 2 a variety not seen in the Hamilton occurs. To 

this is given the varietal name gamma. (See Pl. IV, figs. 7 and 8, and Pl. V, fig. 3.) The specimen selected· as type for this variety is a mold of the interior showing. both valves and having 

the following dimensions (in millimeters): L=26; W =46 (twice the width (23) of the more 

perfect side; the actual width shown is 37); A= 18; D = 7.3; F =(estimated) 13. These dimensions reduced to scale are 1=100; w=177; a=69; d=24; f=50. They may be generalized 

as follows : l = 100; w = 17 5 to 190 (narrower than in var. typical is) ; a = + 50 (high and nearly 

flat and erect); d = 25 to 30 (narrow and high); f =50 or less. The fold in this .specimen is 

probably artificially flattened, as in general the fold of this form is narrower. Several specimens have been seen showing these general proportions. 

The dimensions being of the interior may not accurately express outside 1neasurements, 

but the proportions· are probably approximately the same. 

SPIRIFER 1\IARCYI DELTA. 

The type specimen representing Spirifer marcy~ delta (see Pl. IV, fig. 9; Pl. V, fig. 13) comes 

from the faunule El. 6L, 1q. This is in the recurrent zone No. 2, southwest of Southport, 

in the Elmira quadrangle. 
• 

60 RECURRENT TROPIDOLEPTUS ZONES IN NEW YORK. 

The type specimen is a not altogether perfect mold-of the interior, and the following measurements (in millimeters) are somewhat estimated: L= 19; W ~40; A= 10; F= 10. Reduced 

to-scale, these become.: 1= 100; w=210; a=52t; f=52t. Another SI)ecimen gives the following dimensions (in millimeters): L=26; W=61; A=18; these 'correspond to 1=100; 

w = 234; a= 69. From these measurements the following values may be assigned to the varjety 

delta: 1'=100; w=200 to 250; a=50 to 75 .. 

In this form two new morphologic characters are expressed: (1) The plications near the 

middle of the shell, on both sides of the fold and sinus, show furrows in the upper surface tending 

to dichotomize the plications at the front; and (2) the sides of the sinus bear two shaliow grooves, 

producing the appearance of two distinct pljcations of the same size as those outside the sinus. 

These are inconspicuous above the middle, but for the front part of the shell they are well 

defined. The surface pustules are fine and closely arranged and· not so elongate or loosely 

distributed over the surface as in variety typicalis. . 

The additional plications on the _slopes of the sinus resemble those described 1 as characterizing some specimens of Bpirifer parryana of the Lower Devonian. S. parryana is a closely 

related species and is near this vari~ty in form. Its surface sculpture is, however, made up of 

fine "longitudinal lines instead of consisting of ·distinct pustules irregularly distributed over 

the svrface, as Spirifer mar:cyi delta. 

SPIRIFER ~MARCY! EPSILON. 

The specimens I have selected to ill·ustrate the variety epsilon are from the northern slope 

of Ashland Hill, a few miles southeast of Elmira, at· an altitude of about 950 feet, well up in 

the Chemu~g formation. (See Pl. V, figs. 9 and 12.) It is aform ·much extended laterally, 

with high area; the greatly elongated pustu~es are arranged in parallel lines, giving the appearance of pustulated lines, and the plications near the card.inal extremities on the pedicle valve 

are in some specimens increased by intercalation. The dimensions of this ~pecimen (in milli~ 

meters) are: L =(estimated) 13; W =(estimated) 50, A= (estimated) 10, F ~ 9, D = 6. Reduced 

to scale these dimensions give I= 100; w = 384; a= 77; f = 69; d = 46. 

The area is thus high and erect and the width of both area and delthyrium high, and the 

variety may be described as a much-mucronated form of variety beta. The form shows extre~e 

production laterally; the elongate pustule~ run into distinct lines in the sinus; a faint indica-

_tion.of an auxiliary plication is seen on the slopes of the sinus; and a distinct intercalation of 

a plication between two regular ones, near the cardinal extremity of one of the wings, is evident. 

These pustules and plica tions ·are new characters. 

SPIRIFER MARCY! ZETA. 

Several specimens, here called zeta (Pl. V, fig. 8), show an attenuation of the cardinal 

angles still greater than that of var. ·epsilon but do not possess the special surface s~ulpture of 

the latter. · 

The specimen selected as type of this variety is from fauna of Wv. 7B, 1f. In form, zeta 

·is very 1p.uch like epsilon, but its pustules are fine, numerous, and not a_rranged in parallel lines, 

and the bifurcation 'of its plications or their ·addition by implantation in process of growth 

is not evident in all specimens, though. it appears OJ?. the type specimen near the extremity o1 

the attenuated shell. 

The actual dimensions of this type specimen of variety zeta are (in millimeters) : L = 6; 

W = 27 to 32; A= 5 + ; .F = 3 + ; these correspond to I= 100; w = 450 to 530 (estimated from 

one side); a= 83 (estimated from one side); f =50 . 

. This in general terms is a laterally much-produced attenuate form with broad fold and 

sinus, fine pustules, and occasional implantation of extra plications between the cardinal margin 

and the lateral extremity of the shell. It is in form the var. epsilon without the new characters 

of that variety. · 

1 Calvin, Samuel, Bull. Lab. Nat. Hist. State Univ. Iowa, vol. t' 1888, p. 24. 

.A 
\'r' 

SPIRIFER MARCY!. 61 

THE RUDIMENTARY SYRINX. 

Occurrence.-On sever"al specimens of the Spirifer marcyi gens, not confined to those of 

any particular variety as expressed in. terms of forn1, a rudimentary syrinx has been observed. 

(See Pl. IV, figs. 8 and 10, and Pl. V, figs. 4 and 7 .) Tills new character consists of an infolding 

of the outer wall of the transverse plate near the apex of the umbonal cavity into two more or 

less twisted, narrow, short plates. In order to designate the appearance of this new character 

h:respective of the vu.rietal form of the specim.ens expressing it, I have used the v_arietal name 

s~gma. 

Spi1·ijer granulosus.-The earliest representative of the rudimentary syrinx I have seen 

is in specimens of Spirifer g1·anulosus clintoni I-Iall (Pl. V, fig. 4), collected by C. S. Prosser 

frmn the llmnilton fauna at Pleasant Brook, Upperville, near Smyrna, and listed by him 1 

as "SzJirifer g1·anulosus (Con.) I-Iall and Clarke." 2 

The specimen, which is somewhat crushed, is a mold of the interior.· Its dimensions (in 

n1illimeters) are: L=21; W=40 (estimated; actually, 37); A=(estimated) 6; D=(estimated) 

6; F=not over 11 (actually 13); ·these correspond to 1=100; w=190; a=28!; d=28!; 

f=50. 

The forn1 is thus seen to be, in tern1s of the fluctuating characters, below variety typicalis 

of the Spirij~r marcyi group in the· values of a and d and about equal to it in the value of w. 

~ J?JG. 15. ~ 

~~ 

FIG. 16. FIG. 17. FIG. 18. 

Frounro: 15.-Cross section or beak or Spirifer granulosus sigma, showing rudimentary syrinx. t, t.', Teeth plates; s, transverse plate connecting 

tooth plates. 

J?rou•u~ 16.-Cross section of beak of nom1al Spirifer granulosus. tr, Transverse septum connecting teeth plates, t, t', at apex of interior of pedicle 

valve.. . 

Frouug 17.-Cross section of beak of Spirifer marcyi sigma, showing rudimentary syrinx. 

Ftoum~ 18.-Cross section of beak of Syringothyris sp., showing complete syrinx. 

It has the n1edian gro.ove in the fold and the faintly Inarked plications on sides of the 

sinus defined as characterizing son1e specin1ens ·of Spirifer granulosus. 

·The rudi1nentary syrinx is represen•ted by an irregular twisting of the transverse plates 

.. at the apex of the beak represented in figure 15. The form shown may be called Spirifer 

g?'a,nulosus sigma. . 

Other specimens of similar external appearance appearing in the san1e faunule do not 

exhibit this varietal character, but are--like the normal Spirifer granulosus, as shown in figure 16. 

Spirifer marcyi sigma.-In some of the recurrent representatives of Spirifer marcyi in the 

Upper Devonian the twisting representing the rudin1entary syrinx is seen; but more generally 

the character is expressed as in Plate IV, figures 4 and 6. , The speci1nen chosen for illustrating tlus character in Spirifer marcyi (Pl. IV, fig. 10) is from 

station Dr. SI, lc. It is the n1old of t.he interior of a pedicle valve whose din1ensions (in millinleters) are as follows, viz: L (estimated), 21; W (one-half=27),54; A (estilnated)=13; D 

(estin1ated)=9; these correspond to 1==100; u=257; a=62; d=43. 

In form it comes, therefore, into variety beta. The outer edge of the transverse plate 

between it and the pseudodeltidiun1 is not preserved; if it be assumed to be flat, figure 17 

expresses the cross section of the shell near the apex of the beak. 

In the n1olds this character is expressed by two ridges starting near the apex of the cavity 

and running downward toward the center of the shell with the ou.ter faces convex and the 

inner surfaces concave; it thus forms, ·on the outer face of the transverse plate, a scooplike plate, 

1 Prosser, C. s.; Tho classification and distribution or the Hamilton and Chemung series of central and eastern New York: Fifteenth Ann. 

Hept. State Geologist, New York, 1895, p. 119. 

2 Paleontology: Gcol. Smvcy New York, vol. 4, 1867, p. 223: 
62 RECURRENT TROPIDOLEPTUS ZONES IN NE"\V YORK. 

Examination of the fluctuating characters exhibited by the Spirifer marcyi race as it passes 

from Middle Devonian through the recurrent zones ·in Upper Devonian has led to the discrim-

- ination of eight varieties-typicalis, alpha, beta, gamma, delta, epsilon, zeta, and sigma. 

In the following table I have arranged the specinlens from the several recurrent Upper 

Devonian zones so as to exhibit the particular varietal form ·assumed in each locality and zone. 

1 King, W., Monograph of Spirifer cuspidatus (Syringothyris cu8pidata) Martin: Annals and Mag. Nat. Hist., 4th ser., vol. 2, 1868, pp. 20, 21 

,and Pl. III, figs. 31 and 32. ' 

2 Op. cit., p. 22. 

.t. 
,'> 

SPIRIFER MARCY!. 63 

Geographic and geologic distrib·ut1:on of the several varietalfonns of the gens Spirijer marcyi in the Upper Devonian. 

Faunule. In 

Ithaca 

member. 

Zones. 

No.1. No.2. No.3. 'rypicalis. 

Varietal types. 

p 

--1------------------:------------------------

58 

00 

c 

20 

28 

20 

32 

33 

33n 

33h 

32n 

. 34 

34 

30 

34 

34 

3(in 

1 

2 

3 

5 

7n 

50 

Ap. liE, la ........................................ ..... ........ ........ X ········ ·········· X ······ ······ ·····~······ ······ Ap. 13L, !........................................... .... ........ ........ X ........ .......... X X ...... : ................ . Dr.14N................................................. X .................................. X .............................. . 

1~~Jl?: E:::::::::::::::::: ::::::::::::::::::::::::::::: ::::::::. g :::::::: :::::::: :::::::::: g X ......... ···j· .......... . 

.

Dr.li1,.1E.l\LK......................................... ........ X .......................... X ::::::::::·:·· ::::::::::·:._ ::::.::::::::,::::.::::_:::: ·:·:x:x··:·:·: Dr. 71, ln................................. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . X . . . . . . . . . . . . . . . . . . X 

Dr.SI,lc ................................................ X .................................. X Dr. 81, lc2............................................... . . . . . . . . . X . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . X ........................ . Dr.SI,.Ic................................................ ........ X .......................... X .......................... . 

B~: ~~[~~;)::::::::::::::::::::::::::::::::::::::::::::::: :::::::: ... x··· ·--~·-· :::::::: ·····?····· ~ ··x·· :::::: :::::: :::::: .. ·~--

1~~: ~J~·~~(I:':::::::::::::::::::::::::::::::::::::::·.:::::: :::::::: ~ :::::::: :::::::: ·····?····· ~ ···?··· :::::: :::::: ''x'' :::::: 

!l.~:/lj.rt:::;;::;:;:::;::;;:;;: :: ::::: ::::::l::::::: :··g_:: ·:.i( ::(! :::::: : I ::~ ::X: : :::: ::::: : ~:: l:ld. 12L, ll................................ . . . . . . . . . . . . . . . . . . . . . X . . . . . . . . . . . . . . . . X X ....................... . lld. 11\1, 1i................................ . . . . . . . . . . . . . . . . . . . . . X . . . . . . . . . . . . . . . . X X ....................... . 

42 ~~-- ~~~:Y. :::::::::::::::::::::::::::::::::::::::::::::: :::::::.: ... ~ .. ·. ···x·'· :::::::: .......... ~ ~ :::::: :::::: :::::: ··x·· ~g g~~:g~:~~::::::::::::::::::::::::::::::::::::::::::::: :::::::: ~ :::::::::::::::::::::::::: ~ ~ :::::::::::::::::: ''x'' 40 Ow.l4C,l ...................................................... X .......................... X X ....................... . 41 Ow. 11, ld............................................... . . . . . . . . . . . . . . . . X . . . . . . . . . . . . . . . . . . X X ....................... . 41n Ow. 11, .If................................................ . . . . . . . . . . . . . . . . X . . ... . . . . . . . . . . . . . . X ..........•................... 

~ ~J~·. ~~r:.11 ~ · :: :: :: : :: : :: :: :: :: : : : : : : : : : : : : :::: :: : : : : : :: : :: : : :: :: : ::::::: ~ : :: ::::: ::: :: ::::: ~ :::::: :: ::: : : ::: :: ::: ::: · · x · · 0 \Vv.lA,li.............................................. ........ ........ X .................. X .......... , .................. . 

g ~~~: ~~:l~::::::::::::::::::::::::::::::::::::·:::::::: :::::::::::::::: ~ :::::::::::::::::: ~ :::::::::::::::::::::::: ''x'' 0 \Vv. lA, 1]J.............................................. . . . . . . . . . . . . . . . . X . . . . . . . . . . . ... . . . . . X ............................. . !) \Vv.1A,1r .................................................. :... ........ X .................. X .................. X ..... . 0 \Vv.lA,ls .............................................................. X .................. X .................. X ..... . !) \Vv. JA,lv.............................................. .......• ........ X .................. X ............................. . 10 \Vv.lA,lvvv............................................ ........ ........ ........ X X· ? X ....................... . 10 \Vv. 2A, u·6..................................... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . X X . . . . . . X ? X ........... . 10 \Vv.2A,lo.............................................. ........ ........ ........ X X ...... X ....................... . 

13 

15 

Hl 

17 

18 

24 

20 

50 

31 

\Vv.7.B,lc.............................................. ........ ........ X .................. X ............................. . \Vv.7.B,d............................................... ........ ........ X .................. X ............................. . 

~~~~:: m:J::::::::::::::::::::::::::::::::::::::::::::::: :::::::::::::::: ~ :::::::::::::::::: ~ :::::::::::::::::: ··x·· :::::: 

"rv.7B,jl ...................................................................... X .......... X ............................. . 

~~~: ~1~:J1:i.". ·.::::::::::::::::::::: :·:::::: ::::::::::::::: :::::::: ... x ... :::::::: ... ~ ....... ~.. .. ~ . -~ .... ~ .. :::::: ::::: :·::: ::: 

~~Urf:::::::::::::: :::::_::::: : ::::: . :: · :. : : : ~ } : :::}::::. ~-·:I:::::::: > :x ~~~: !1?2Jd::::::::::::::::::::::::::::::::::::::::::::: :::::::: :::::::: ·--~·-· ···x .. : ····x···· ~ ··x·· :::::: :::::: ::::-:: :::::: 

EI.2M,P4 .................................. · ..... :...... ........ ........ ? .................................... X ........... . 

g~~: ~~~~~~::: ::::::::::::::::::::::::::::.:::::.::::::::::::::: .... ? ... · .... 'i ... :::::::: :::::::::: ~ .. ~ .. :::::: :::::: :::::: :::::: 

Kf."t~t'N~:·:·:::::::::::::::::::::::::::::::::::::::::::: :::::::: :::~::: .. J ... ::-:::::: :::::::::: --~--1:::;:: :::::: :::::: :::::: :::::: 

The numbers preceding the faunal symbol at the extreme left of the table· correspond to 

the numbers used in the table of faunules of the recurrent Tropidoleptus zones on page 10. 

The same number is given several faunules because the recurrent zone of some of the sections 

is not· restricted to a single stratum and its faunule but is found in several strata following 

one another, each carrying one or more of the typical recurrent species. Where no number 

precedes the faunal symbol the particular faunule was not ascribed to any one of the definitely 

established zones, but is from an isolated outcrop, its zonal position being determined by its 

fossils. 

For frfty-seven of these local faunules the horizons are positively determined; for five others 

the exact horizon is not determined; and for the last in the list the characters of the speciri:ten 

are doubtfully determined. 
64 RECURRENT TROPIPOLEPTUS ZONES IN NEW YORK. 

Of the fifty-seven faunules whose horizons are determined, two are from the recurrent 

zone in the Ithaca :rp.ember, nineteen from the Tropidoleptus zone No. 1, twenty-six from the 

zone No.2, and ten from the zone No.3. 

· The variety alpha has been detected in -none of the rec11:rrent zones. The variety beta 

has been seen in fifty-two (doubtful in fifty-third) of the fifty-seven faunules, being missing 

only in a few faunules from the zone No. 3. 

The variety gamma has been seen in twenty faunules (doubtful in three others), of which 

n~.ne are in the Tropidoleptus zone No. 1, four in the zone No. 2, and seven in the zone No. 3. 

This variety, gamma, it will be remembered, is the form with high area and cardinal extension' 

less than 200 per cent of the brachial length. It is a form not recognized among the Hamilton 

- representatives of the species. 

Variety delta is typically represented in two of the fifty-seven faunules and doubtfully in 

a third. One positive occurrence is in the Tropidoleptus zone. No. 2; the other positive and 

the one doubtful occurrence are both in 'the zone No. 3. This variety does not appear until 

the opening <;>f the Chemung epoch. 

The variety epsilon is typically from a faunule on the side of Ashland Hill south of Elmira 

(El. 2M, P4) at a horizon which ~ clearly in the Chemung; but on a~count of the peculiar 

combination of species in the faunule and the absence of Spirifer disjunctus (characteristic of. 

the Chemung) _from all faunules of the section both below and above, its exact place n1 the 

standard section is doubtfuL The only other specimen of variety epsilon came from one of 

the outcrops of zone No.3 (Wv. 2A, W5), which is stratigraphically equivalent to the·recurrent 

zone No. 10 of the list on page 10. The Ashland Hill specimen is undoubtedly as high as 

zone No. 2·but it may be of later stage. 

Variety zeta is represented in five faunules, one of which is from the Tropidoleptus zone No. 

1, and the other four are from the zone No.2. This variety is very much like epsilon in form; 

but in epsilon the elongation of the pustules into nearly parallel lines and the implanting of 

new plications during the growth of the sh~ll is indication of progress in evolution beyond 

the stage reached by zeta. Neither of these forms is represented in the Hamilton formation 

of New York. In their high area and transverse elongation they resemble the species called 

Spirijer angustus by Hall/ but differ from that species by their pustulose surface. · 

I have checKed as variety typicalis several specimens from the Upper Devonian which, in 

the degree, of fluctuation of the several characters here noted, fall characteristically within that 

group in the Hamilton; that is, their trailsverse extension (w) is moderate, being not over 

two hundred; their height of area (a) is also n1oderate, not over thirty-five; and their ,plications 

are approximately twenty on each sid.e. Their pustules, however, -are generally much finer and 

more closely spread over the surface ·than in specimens of the variety typicalis from the 

Hamilton. 

A few forms from the earlier recurrent zones· (No. 1 and No. 2) approach these characters 

but differ in having the area higher and the transverse extension less than in typicalisJ· by 

these characters they approach the variety gamma, and I have indicated them by a question 

m~. . 

In the variety typicalis column are seven positive and seven doubtful checks, as above 

defined. All seven of the doubtful occurrences are ill faunules of the zone No. 1, and all of 

those positively iderJ.tified are from the zone No. 3. The variety gamma is also more numerous 

in these two zones. When it is remembered that the question is one of fluctuation," and that 

the samples are from successive zones and express successive stages l.n the history of the race, 

the significance of these lists becomes apparent. · 

STAGES IN EVOLUTION OF THE SPIRIFER MARCYI GENS. 

Variety beta expresses the mean fluctuation of these several characters for the Upper Devonian stage of evolution. Variety gamma expresses the extreme fluctuation in the direction 

of short cardinal extension and high area. Variety delta expresses an extension of this general 

1 Paleont_?logy: Geol. Survey New York, vol. 4, 1867, Pl. XXXVIII, figs. 28-31. 

'".·~·. 
.. 

GENUS DELTHYRIS. 65 

forn1 gamma in respect of pustule and plication; the pustules are decidedly elongate, the sides 

of the sinus aJld the fold show the rudimentary plications seen in some specimens of Spirijer 

granulosus and other species, and ridges occur on top of the plications, tending to dichotomize 

thmn near the front; this variation is not assumed till the stage of the Tropidoleptus zone No. 

2. Variety ty1Jicalis expresses the tendency shown in gamma carried farther from the mean 

(var. beta), in the d:iJ:ection of both shortening the transverse extension and lowering the relative height of the area. It is this extren1e in fluctuation which was selected by the author of 

the species for the type figure of the species Spirijer marcyi of the IIamilton. In the I-Iamilton 

the lowest area was reached by the transversely elongate forms here called variety alpha, a 

variety which does not reappear in the Upper Devonian faunas. The forms with low area and 

short hinge extension are placed in the species Spirijer granulosus "Qy the definition of I-Iall. 

They fail to reappear in the recurrent Upper Devonian faunules. 

In the other direction from the mean represented by variety beta, the first stage of fluctu- · 

ation is seen in variety .zeta, in which the transverse hinge extension is excessive, but in which 

the high area is retained. This variety appears chieflJ in the Tropidoleptus zone No.2, a single 

specunen appearing n1 tlie stage zone No. 1. ·It is followed by the variety epsilon, ·in which the 

tendency is to n1crease the plications with growth and to elongate the pustules into paralle 

lines. 

GENUS DELTHYRIS. 

RANGE OJ<' SPECIFIC CHARACTERS. 

' The genus Delthyris, as shown by its early confusion with S1Jirijer pennatus posterus, does 

not differ greatly in external fonn fro1n the conin1on. ~pirifer of the Ithaca shale member of 

the Portage for1nation. A thorough search of the collections den1onstrates, however, that the 

distinctive 1nark of the genus Delthyris (the median septun1 of the ,pedicle valve) does not appear 

in any specin1ens of the fauna of the Ithaca member, not even in the zone in which RhipidoInella and "Tropidoleptus are found .at that lower stage. It is not until the second incursion 

(the stage introducing the recurrent fauna of the zone No. 1) that the septum ··appears. I 

have exan1n1ed a great number of specimens (every on~ in the collections), and have failed to 

discover a single one, n1 any faunules from below the Enfield shale member of the Portage forInation, which shows anything more than a slight, linear elevation on the interior of the pedicle 

valve where the septun1 appears n1 Delthyris. The earliest appearance of a distinct septum 

is in son1e specnnens fro1n the lower part of the Harford :Mills section (l-Id. 12G, lc and ld), 

at an altitude of about 1,200 feet, collected by Mr. Reinecke. The specimens are asso'ciated 

with Hhi.pido1nella and occur 250 feet below the Tropidoleptus zon~ No. 1 of this section, in 

which Tropidoleptus, Rhipidomella, and Delthyris appear; and it is not until the highest p~rt 

of th:at zone is reached, at 1,500 feet elevation (300 feet above this frrst incursion), that Spirijer 

marcyi is found in the sa1ne faunule with it. 

Th(;) rmnarkably long range of the zone No.1 fauna in the eastern side of the area is associated 

with a remarkable thickening of the portion of the Enfield member through which the general 

brachiopod type of faunules ranges. In the western part of the area (west of Ithaca) the Enfield 

n1mnqer shows scarcely a trace· of brachiopods for nearly 600 feet-above the top of the Ithaca 

men1ber. In the Dryden,· Owego, Waverly, and Ithaca quadrangles; the recurrent zone No. 1 

is restricted to not over 200 feet of strata; and generally the fossiliferous zone is n1uch narrower. 

In tlu1t zone, however, Spirijer 1Jennatus posterus is replaced by Delthyris mesicostalis whenever 

it appears, thus furnishing a reliable guide in the field for distinguishing the higher recurrent 

zone No. 1 fron1 the Ithaca member below, in which Spiri.fer pennatus posterus is a characteristic and often· an abundant specieR. 

Above the first appearance of Delthyris in the section~ throughout the Cayuta n1ember and 

upward lllto the vVellsburg n1ember of the Chemup.g, all'the spiriferoid species at all resen1bling 

the few-plicated Delthyris me~icostalis, or the wide and inucronately extended S1Jirijer pennatus 

with nmnerous plications, have the delthyroid septun1. The exter~1al appearance of Delthyris 

67437°-No. 79-13-5 
66 RECURRENT TROPIDOLEPTUS ZONES IN NEW YORK. 

mesicostalis in its smaller, less developed forn1 is very similar to the external appearance of 

Spirifer pennatus posterus, which is very abundant in the early stages of the Enfield member in 

the Harford quadrangle. In specimens of the pedicle valve showing the mold of the interior 

the true Delthyris shows a distinct septum. 

The 'specimens referred 'to Delthyris are distributed as follows by quadrangles: 

Occurrence of Delthyris. 

Quadrangle. 

Faunulescontaining 

Faunules Delthyris and the 

diagnostic gen- contain- era. ing Delthyris. 

Number. Per cent. 

------

10 5 50 38 23 60 ~ri1:F:~:·:·:· :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: 37 4 10 Harford ... · ....................................................................................................... . 49 27 55 

5 1 20 ~~~~~·.-:::: :::::::::::: :·::::::::::::::::::::::::::::::::::::::::::::::::::::::: ::::::::::::::::::::::::::::::::::: 25 8 32 Watkins .................................................... , .................................................... . 5 ............ ---------- Waverly ....................................................................... c •••••••••••.••.••••••••••••••••••• 133 34 25+ ---------

302 102 33+ 

In the Ithaca and Watkins quadrangles only a few faunules contain Delthyris and only 

one of these few is in a recurrent zone; this is because the surface exposures in these quadrangles 

are of rocks below the zone No. 1, that is, of the Enfield member of the Portage formation. In 

the Dryden and Harford quadrangles, on the other hand, more than the average percentage (60 

and 55) of the occurrences are in tfue recurrent zones; 'this is because there are many outcrops of 

the zone No-:' 1 in these quadrangles and not many of the Chemung rocks. In the Apalachin, 

- Elmira, Owego; and Waverly quadrangles 50 per cent or more of the occurrences of Delthyris 

are outside of the recurrent zones; this is because the rocks exposed in these quadrangles are 

chiefly Chemung, and Delthyris is plentiful in the Chemung outside the recurrent zones. 

Abov·e the Hamilton the genus Delthyris does not distinctly appear in the faunas till the 

Tropidoleptus zone No. 1 is reached; of the 26 sample faunules selected for special study from 

the zone No.1 all but three contain Delthyris, and these three probably hold the genus, though 

no specimens were actually obtained. Above the zone No. 1 Delthyris is found abundantly in 

the rocks of the Chemung. Many of the upper Portage faunules containing Delthyris may belong 

to the fauna found in the particular, restricted, Tropidoleptus zone No. 1; but they are at 

present ruled out as not strictly represeJ).ting the recurrence because of their lack of the three 

d~_agnostic forms above specified. 

PROBLEM OF RECURRENCE. 

The disappearance of the earlier forms (like Spir1fer pennatus posterus) contained in the 

Ithaca member of the Portage may be explained as resulting either (1) from their extinction in 

the area, or (2) from their modification on passing upward into the new type Delthyris mesicostalis. · 

This involves the question of their recurrence-whether Delthyris persisted in the area in 

modified form or whether it retreated and came back later, unn1odified, with the other Tropidoleptus fauna. The data are not yet sufficient to show positively which of these has taken place. 

However, in my .early study of the problem I had strong conviction that the later forms (called 

properly Delthyris mesicostalis) were directly evolved from the earlier forms, now known as 

S pirifer pennatus posterus. · 

The difficulties in reaching a satisfactory conclusion are as much rational as observational. 

In the Hamilton, below, Spirifer pennatus and Delthyris consobrinus are thoroughly differentiated. In 'the recurrent zone No. 1 some· of the speci1nens of Delthyris mesicostalis show no 

visible morphologic characters by which they may be distinguished from their forerunner, 

D. consobrinus. So great is the resemblance of the two species, emphasized as it is b.v the 

~ 

'(' 

... 

..... 
) 

.l 

GENUS CAMAROT<ECHIA. 67 

SPECIFIC DISCRIMINATION. 

In the fn,unnJ list I have divided the representatives of the genus Ca,marotrechia into four 

groups, calling then1 Oamarotmchia congregata, 0. eximia-stephani, 0. sappho, and 0. contracta. 

Selected specimens may be taken which fairly well represent the specific types indicated by the 

mtines, but the fluctuating characters are so constantly expressed, as the genus passes upward 

frmn the I-Ian1ilton, that it is difficult to distinguish between characters which are of evolutional 

significance and normal fluctuating ·variations .. I have not subjected the characters to the 

1ninute 1neitsuren1ent and statistical tabulation necessary to demonstrate their historic Telations. 

A few rmnarks, however, may' be n1ade regarding the broader characteristics expressed as they 

mount through the Upper Devonian beds. 

The genus is not confined to the Tropidoleptus recurrent zones. 

The group called by n1e Oamarotmchia eximia-stephani, because the n1ajority of its specimens present the characters of these two species as defmed, is less common in the fiamilton 

than. in the Upper Devonian. The young or small specimens, all of which are very similar, 

are common all through the Ithaca member, and a few of them appear higher up. The adult 

form, which has the beaks rather narrow and the sides straight (typically called Oamarotmchia 

stephani), is common in the Ithaca and scarce above. The broader forms reach the form called 

0. eximia in the recurrent zone in the Ithaca and in the zone No. I. 

The gibbous type called 0. sappho is rarely seen in the Ithaca but is conspicuous in the 

zone No. 1 of the Portage and in the higher faunas of the Chemung. 
68 RECURRENT TROPIDOLEPTUS ZONES IN NEW YORK •. 

The form with few plications, smaller 4t size than G. sappho, with which it is associated, is 

G. contracta. This species is rarely seen in the Portage but is conspicuous in the Chemung. 

~n the Tropidoleptus zone No. 2 a conspicuous form resembles G. congregata as it appears 

in the Hamilton but is associated with G. eximia, G. sappho, and G. contracta forms. 

PROBLEM OF RECURRENCE. 

Here again the facts inay be explained in two ways. It may be supposed (1) that such 

forms as G. eximia-stephani have undergone evolutional modification as they have passed 

upward into the Chemung, or (2) that the differences at the higher horizons result from the 

incursion of species that have retained their ancestral character unchanged. No satisfactory 

conclusions· on "this subj~ct can be reached with the present knowledge of this generic group. 

For the present it is sufficient to state that, Camarotmchia can not be used to strengthen the 

hypothesis of recurrence for the chief reason that the genus occurs in the intermediate faunules 

as well as in the particular zones carrying the ~haracteristic Hamilton types. 

GENUS CYPRICARDELLA .. 

' RANGE. 

Although the genus Cypricardella is shown to occur numerously in the recurrent zones, its 

great rarity in typicn.l samples of the Tropidoleptus zone No. 1 casts doubt on its direct origin 

from a I-Iamiltonian source. Its· abundance in some of the Hamilton zones makes such an 

origin possible, but its presence in the fauna of the Ithaca member, outside the zones in which 

the Tropidoleptus has been actually detected, casts still further doubt upon its legitimacy as nn 

element of the Tropidoleptus recurrent fauna. The reason for at first supposing that it was a 

constituent of the recurrent fauna was its discovery in the Tropidoleptus zone No. 2 in the first 

find containing Tropidoleptus and Rhipidomella. In these recurrent zones. all three genera 

are represented by species showing no- appreciable modification from the common Hamilton 

·· representatives. As the search 'was extended, Cypricardella was found to be not always assoCiated with the other two and it was also seen in strata showing neither,of the other more characteristic H·amilton species. This began to throw doubt on the first hypothesis, and asothe statistics were finally put together it was seen that few faunules of the Tropidoleptus zone No~ 1 hold 

Cypricardella. 

Close examination of the faunules disclosed 116 that contain Cypricardella. Not all of 

these belong to G. bellistriata, but the others are of closely allied species, evidently modified 

permanently from that stem. The finds are distributed as follows: .Apalachin, 7; Dryden, 5; 

Cortland, 14; Elmira, 14; Harford, 30; Ithaca, 6; Owego, 6; Waverly, 34. 

Of these 116 faunules only 35 can be shown to belong to the zone in the Ithaca member and 

to zones Nos. 1, 2, and 3. The genus appears scattered all through the Upper Devonian beds, 

· from the earliest traces of the Ithaca fauna in tP-e Portage formation to high up in the Wellsburg 

member of the Chemung. It is particularly noticeable in the faunules of the eastern extension 

of the Ithaca member in the Harford and Cortland quadrangles, and ill the general Cayuta fauna 

not restricted to the particular Tropidoleptus zones Nos. 2 and 3. All specimens seen associated 

with the other recurrent species present the surface characteristics of Gypricardella bellistriata, 

but many of t:q.em are small in size. It has been discovered in only two of the recurrent zones 

on the eastern side of the area-Harford Mills (l-Id. 13G, 1rr) and Lisle (Hd. 2J, 1e). It 

is present in eight of the eleven samples of zone No. 3. Altogether there are rather strong 

reasons for believing that the species Gypricardella bellistriata came in to the central New York 

area with. the Ha~iltonian m~gna fauna, but that its migratory niovements were l~ss rapid, it 

being both slower to arrive and adopt the n~w conditions and also slower to depart when the 

general fauna withdrew. The specific forms of -the genus more intimately associated with the 

Upper Devonian faunas ·are not typical G. bellistria:ta and they n1ay perhaps be considered as 

mutants adjusted to remain, when the typical species of the recurrent zone withdrew, or were 

extinguished by the prevailing conditions of the environment. 

' ' 

I ( 

,l.. 

~-
I 

> 

r' 

GENUS CYPRICARDELLA. 69 

The species Oypricardella bellistriC!'ta is a diagnostic and often an abundant constituent of 

the r~current fauna in the Tropidoleptus zones Nos. 2 and 3. 

SPECIFIC CHARACTERS OF CYPRICARDELLA BELLISTRIATA. 

HAMILTON FORMS. 

Oyz)ricardella bellistriata was first described and figured by Conrad/ who in 1842 defined as 

follows, under the name Jficrodon bellastriata, the species here tern1ed Oypricardella be.llistriata 

typicalis: . 

Much compressed, with very regular equal, concentric strire; hinge margin slightly declining and nearly straight; 

posterior margin wide, direct; a slight fold anterior to and parallel with the umbonal slope. 

Near Smyrna, Chenango County, New York. Upper Si,lurian shale [=Hamilton formation]. 

IInll,2 in 1885, gave 1nany figures of the species, illustrating its widely variable form; his 

figures 10 a.nd 14 very closely represent the forn1 adopted by Conrad as typical of the species. 

Two conspicuous varieties of the species 1nay be recognized-one,, represented by Hall's 

figures 7, 8, 15, and 21, in which the dimneter fron1 front to back is shorter than in typicalis, may 

be cnlled 0. bellistriata'alpha; the other, represented by figures 16 and 17 and11, in 'Yhich the 

same dimneter is longer than in typicalis, may be called 0. bellistriata beta.. These two varieties 

are supposed to be true 1nodifications ·of forn1, irrespective of the considerable modification produced by distortion. Such a forn1 as Hall's figure 9 is in1agined to have been produced by d~stortion of an original var. alpha, the crushing having shortened· the umbonal ridge and relatively 

.increased the distn,nce fr01n the posterior cardinal angle to the anterior ventral angle. ·Figure 22 

shows distortion in a diametrically opposite direction; that is, a shortening of the shell from the 

·posterior cardinal angle to the a.nterior ventral corner and a lengthening of it along the umbonal 

ridge. · 

. The I-Imnilton specimens figured on Plate VI (p~ 98) of this paper exhibit the san1e differences in fonn; ·figures 5, 8, and 14 are fair samples of var. typicalis; figure 2 represents var. alpha; 

and figures 1 and 6 represent var. beta. Fluctuation in 'the strength of the concentric surface lineations is also observed; figure 1 exhibits the extreme in coarseness and figure 6 the extren1e in 

fineness for the Ila1nilton specimens selected for illustration; the other specin1ens are intermediate and express the characters ·more frequently met with in l-Ia1nilton specimens. The 

shells are generally.-quite flatly compressed, but figure 5 shows a specunen not otherwise different 

preserved in 1narkeclly convex state. The relative position of the beak also varies, as may be seen 

by comparing figures 1 and 5; another specimen (fig. 14) fro1n the sa1ne locality is still shorter in' 

front of the beak. 

Thus, in all of the ele1nents of fonn and surface 1narkings the Hamilton forn1s express distinct fluctuation. 

PORTAGE FORMS. 

The Portage specunens, all of which are from the lower recurrent zone (in the Ithaca nlember), express.one constant character separating them fron1 the IIanlliton representatives varie- , 

tally but not .specifically. They are duninut:ive in size and their lineations are correspondingly 

finer, but in form they preserve not only the specific but the fluctuating characters of the 

I-lmnilton representatives. If it were necessary to use a nmne for this expression of the gens, 

Oypricardell(t bellistriata minor is appropriate. On Plate VI, figures 7, 9, and 10 show this 

peculiarity. Con1parison of figure 9 with figure 5 Inakes.evident the differences in size, for figure 

9 represents the largest specimen from the Ithaca locality. 

Figure 12 of a specin1en fron1 the same beds shows coarser lineations, linking it with typical 

I-Ian1ilton specimens. The specimen is seen by exa1nination to be distorted and its shape can 

not be considered nonnal to the species. 

• Conrad, '1'. A., Jour. Acad. Nat. Sci. Philadelphia, vol. 8, 1842, p. 247, Pl. XIII, fig. 12. 

, 2Hall, James, Paleontology: Gcol. Survey New York, vol. 5, pt. 1, Lamcllibranchiata, ir, Pl. LXXIII. 
70 RECURRENT ~ROPIDOLEPTUS ZONES IN NEW YORK. 

CHEMUNG FORMS. 

In the next recurrence, in the Tropidoleptus recurrent zone No. 2, where Cypricard~lla is 

associated with Tropidoleptus and other recurrent Hamilton species, the only definite modification I can detect is in the concentric lineations of the surface; these are less uniform than in the 

1najority of Hamilton representatiyes of the species 0. bellistriata. But the difference is slight, . 

as will be noticed by examination of Plate VI, figures 13, 15, 16, 17, 18, and 21, all of which are 

of specini'ens fr01n the zone No.2. Figures 15 and 18 differ little in this respect from the Hamilton expression in figure 8, but none of the figures from zone No. 2 show the remarkable evenness of lineation expressed, by figures 1, 2, 3, and 4 from the I-Iamilton. · 

The artist has reproduced the characters faithfully, and a glance at the figures will show 

the difference. . I an1 inclined, however, to think the difference is partly, if not wholly, due to 

difference~ the nature of the sedin1ents. The Hamilton specimens con1e fron1 a soft argillaceous 

shale, whereas the specin1ens from the zone No.2 come from· an arenaceous shale and had their 

surfaces somewhat broken in separating them from the rock n1atri..~. The lineations, however, do 

not show the fasciculation characteristic of 0. complanata and to some degree of 0. tenuistriata. 

In form the specimens of zone 2 exhibit the varietal characters called typicalis, alpha, and beta, 

but no extremes of the variety alpha have been seen. 

The specimens from the Tropidoleptus zone No. 3 show the characteristic concentric lineations; the two figures (figs. 18 and 20) show the types of var. typicalis and var. alpha. As in 

the I-Iamilton representatives, the lineations are sharply defined and regular. 

SUMMARY. 

The review of the characters shows that the liinits of fluctuation expressed by the Hamilton 

representatives is not departed f~om in 'the later recurrent stages of the history. Local pecu- . 

liarities and individual differences are expressed, but the specific characteristics are preserved 

with the same degree of persistence and the sa1ne fluctuations expressed by its representatives 

in the I-Iamilton formation. ' 

EUROPEAN OCCURRENCE. 

It is beyond the province of this paper to discuss the problems of nomenclature and taxonomy suggested by the sudden cessation, long ·disappearance, and evident .return in force of 

the fossil fauna. It is also beyond it to attempt to trace the wanderings of the fauna into 

other regions of the earth during its absence from New York State. Nevertheless, a word n1ay , 

be appropriate in regai:d to the relationship between this recurrent fauna and the one fauna 

in Europe ·with which it seems to· be in some way connected. . 

Beushausen 1 in 1889 described the species Oypricardella elongata from the Lower Devonian 

in the Lower Coblentz strata of the Rhenish province of northwestern Europe. In 1895 he 

brought together desc~iptions and illustrations of several species of Oypricardella from which 

an opinion may be formed as to the expression .of the genl!s, its faunal associates, and its range 

in the European Devonian. ' 

The European cypricardellas are confined to the Lower Devonian, and the species 0. elongata, which comes within the limits of variation recognized for 0. bellistriata in the Hamilton 

formation in the United States is characteristically distributed in the Lower Coblentz zone, 

where it is associated with five other species of the genus and is preceded by three other species 

contained iii the underlying Siegener zone. No trace of the genus is reported in any higher 

strata in the Rhenish locality. 

· The Lower Coblentz is the European zone at which Tropidoleptus appears; it is regarded 

by Frech 2 as characterized by the genera Tropidoleptus, Rensselaeria, and Cypricardella. 

1 Beushausen, L., Die Lamellibranehiaten des rheinischen Devon: Abhandl. K. preuss. geol. Landesanstalt, n. s., vol. 17, 1895. 

2 Frech, F. (Lethma palmozoica, 1897, p. 151), in describing the next following zone of Spirijcr1Jaradoxus, remarks, '"von den Leitformen der 

l:Llteren Stufe sind vor Allem die Gattungen 'l'ropidoleptus, Rensselaeria, sowie Cypricardella verschwunden." 

.~·-
,iTROPIDOLEPTUS ZONE OF· THE ITHACA SHALE MEMBER. 71 

It is the so-ealled zone of Spirije1· hercynice, and is generally supposed to be stratigraphically 

the equivalent of the Oriskany of the United States. 

Whatever the formational correlation between the New York "and European strata, close 

affinity undoubtedly exists between the recurrent fauna discussed in this paper and the lower 

Coblentz fauna of the Rhein. The faunas I have been dealing with are classified as Upper 

Devonian; the faunas in Europe with which this affinity is traced are classified as Lower Devonian. The facts are clear, and they involve the whole theory of correlation and of geologic 

synchronisn1. · · · 

In this connection the reader's attention is called to a sin1ilar combination of Oriskanian 

and I-Imniltonian elmnents described by n1e 1 ·fron1 the fauna of the upper limestone of the 

brf)ccia of St. I-Ielens Island, Quebec. The fauna can not be regarded as the equivalent of 

either the' Oriska!ly or the I-Ian1ilton, but its relationship with the Lower Coblentzian, which 

contains a 1ningling of the two, is apparent. 

Such :facts lead the paleontologist to be cautious in inferring from specific identity of fossils 

that the geologic tin1e represented is the same for the formation holding them; and suggest that 

the farther separated two. such formations are, geographically, the larger n1ust be the time 

allowance separating the epochs in which they actually lived. If the whole of the :Middle 

Devonian of Europe separates the epoch in which Tropidoleptus, Cypricardella, and Rensselaeria lived together from the epoch when the first Spirifer disjunctus appeared, the conceptions 

of the time relations expressed by the terms Eo-, :Meso-, and Neo-Devonian must be modified 

to lllake the correlation between the two continents consistent with the paleontologic facts. 

It is one thing to discover a lilmness of species and geologic faunas, quite another to infer that 

such likeness in1plies contemporaneity. · 

TROPIDOLEPTUS ZONE OF THE ITHACA SHALE MEMBER. 

I have left the consideration of the Tropidoleptus zone of the Ithaca n1ember for special 

consideration until after the proofs of the recurrent nature of the faunas of the principal recurrent zones had been stated. I did this beeause the proofs in regard to the zone of. the Ithaca 

mmnber are less satisfactory; only faint and scattered traces of the pure Hamilton fauna are 

visible in its lower part, although the whole Ithaca fauna has a strong resemblance to the I-Ianlilton fauna. The general Ithaca fauna expresses only general resemblance to the Han1ilton 

fauna; the particular species as a rule are distinct and the associated species give to the fauna 

a characteristic expression quite distinct from that of the Hamilton. 

The chief reason, therefore, ·for inferring that there was a definite return to the conditions 

which determined the particular combination of species of the Ha1nilton fauna, is the·finding 

of o. few diagnostic species of the later recurrent zones at the base of the Ithaca member. :More 

minute investigation of the ;fossil contents of this lower part of the Portage n1ay bring to light 

cleo.rer evidence; but o.t present the evidence is suggestive. rather than conclusive. If the 

recurrence of Tropidoleptus, Rhipidmnello., and Spirifer marcyi be accepted as evidence of the 

retm:n into the o.reo. of central New York of the conditions which determined -the presence of the 

Han1ilton fauna in the sarne area, the inference is strong that there was a partial return of those 

conditim'ls in the early part of the general Portage epoch . 

.Frmn the other evidence regarding the geographic distribution of the faunas concerned, 

this evidence shqulcl be more significant east of the .vVatk.ins Glen and Catatonk quadrangles 

than it is within that area. 

So far as the life history of the genera is concerned, the samples taken from the zone in the 

Ithacn. n1en1ber 1i1ay be safely regarded as intermediate between the typical Hamilton fo.una 

and the faun~ of the Tropidoleptus zone No. 1, the recurrence of which is established for this 

area. 

t Williams, H. S., Proc. and '1'mns. Hoy. Soc. Canada, 3d ser., vol. 3, sec: 4, 1909, pp. 241-242. 
72 RECURRENT TROPIDOLEPTUS ZONES IN NE'V YORK. 

It is important to take cognizance of this sequence in any attempts to correlate the Hamilton formation by means of fossils. Evidence exists that the representation of the Portage 

(Manticoceras) fauna decreases on passing eastward. If it is found to disappear entirely as the 

beds are followed eastward (just as the Tully limestone and Genesee shale disappear), it may be 

necessary to recognize that an upper stage of the Hamilton fauna prevailed to the east during 

a stage of progress expressed farther\ "\\Test by the Portage fauna. In other words, the facts 

indicate that the Hamilton fauna somewhere persisted in its integrity till after the close of 

Portage time as expressed in the Watkins Glen and Catatonk quadrangles. 

The great difference in faunal contents between rocks of the Cor.tland and those of the 

Ithaca and Watkins quadrangles during the early stages of the Portage formation indicates 

the existence of some partial barrier, such as is admirably expressed by Schuchert, 1 who pictures a tongue of the land, which he calls "Alleghania," running ·!lortheas.tward fron1 Kentucky toward the center of Lake Ontario and separating ·the deeper 'vaters connecting with 

the Atlantic in eastern New York fron1 the Ohio basin of Ohio and western New York. Such 

a shallow.barrier between deeper basins will acoount for the formation of the conspicuous ripplemarked flags deposited over central New York during the early stages of Portage time; and 

for the peculiar "channel fillings" (evidently the fillings of narrow tidal-flat runways) so 

characteristic of the early stages of the Portage rocks in some parts of the area. · 

Some such ·barrier, elevated temporarily into shallows, would account for the separation 

of the Buchiola-Manticoceras fauna, which is dominant for a longer period in the section west 

of the barrier than east of it, from the Tropidoleptus fauna, which in its recurrence is dominant 

for longer periods east of the barrier. It also may account for the marked alter:q_ation in 

occupation of the same area by the two faunas. The Ithaca fauna, although resembling in 

its generic features the Hamil.ton, was eyidently separated and evolved separately from the 

pure !-Iamilton fauna in the Appalachian extension of the Mississippian sea. The invasion ·of 

the Tropidoleptus fauna was, I iniagine, through the New Jersey trough from the Atlantic, in 

which it preserved its original characteristics far into late Devonian time. The appearance of a 

few representatives of the rropidoleptus fauna in the Ithaca member indicates, it seems to me, 

occasional free access of, the waters from the Atlantic into th~, northeastern end of the Appalachian trough, but· not a free and continuous communication between the two basins. 

The gradual el~vation (signified by the estuarine sediments of Catskill type) probably 

closed the Appalachian trough at both ends and extinguished the marine Ithaca fauna before 

the New Jersey channel was·closed; for the recurrent Tropidoleptus faunules of the zones Nos. 

1, 2, and 3 are not modifications of the Ithaca fauna but of the pure Ifamilton fauna. 

I am thus ied to the conclusions that the Tropidoleptus zone of the Ithaca member is (like 

the higher zones, Nos:· 1, 2, and 3) expressive_of a direct recurrence of the true Atlantic magna 

fauna during the occupation of the area by the general Ithaca fauna. The Ithaca fauna was 

evolved from the same magna fauna at an earlier time and entered. the area through the Missis~ 

sippian sea by a more southern passage. The Ithaca Tropidoleptus fauna entered the area, 

like the later recurrent faunas, through theN ew Jersey channel. 

EXISTENCE OF THE ZONES. 

RELIABILITY OF THE EVIDENCE. 

Certain questions will naturally arise in the mind of a critical reader of this report. He 

will ask, for instance: What is known as to the presence or absence of the recurrent genera 

in other parts or' the geologic section~ What is there to sho~v that these "zones" are not simply 

places in the sections where the collectors had the good fortune to find these fossils~ May 

they not be common species of the Upper Devonian not before discovered~ l\1ay not other 

·species mixed with them be fully as important in ~he con1position of the faunas as those selected 

for special notice~ Is it not probable that these species would be 1net with more frequently 

if a closer examination was made of the fossiliferous beds. lying between the particular zones 

reported~ The justice of these and of a number of s~ilar questions I have ·fully realized as 

1 Schuchert, Charles, Paleogeogniphy of North America: Bull. Geol. Soc. America, vol. 20, 1910, Fl. LXXVII. 

.\ 
r.l_ 

EXISTENCE O:E' THE ZONES. 7~ 

I have written the report, and it is because they have met m.e at every stage of the investigation that I have been led to make so deep a study of the subject.· 

'iVhatever n1ay be the true explanation of these recurrent zones it is of first importance 

to establish their existence beyond a doubt and to give the evidence of that existence u1 ~erms 

of fossils; and -to establish this existence it is necessary to show that certain fossils are found 

in these zones and a~e not found elsewhere in the sections. 

EXAMINATION OF THE FAUNULES. 

DIAGNOSTIC GENERA. 

A complete listing of all the species identified in the separate strata is a task which, even 

if accomplished, would be so vast and. would cover so nnwh ground that the evidence would 

,fail because' of its very abundance. I therefore resti'ict the table below to certain genera 

which I have found to be significant. 

Over 1,400 individual faunules have been listed for the Wa~kins Glen and Catatonk quadrang.les, and to these I have a.,dcled 103 from the Cortland quadrangle so as to bring in some of 

the enrlier stttges of the recurrences. The distribution, by 15-minute quadrangles, of the 

faunules containing the 7 diagnostic genera, is shown in. the follmving table: 

Individual jaunules collected and exarnined.frorn the area. 

Number of faunqlcs containingQuadrangle. Nu~}ber I----:---~---,--- ---,----:------:----

faunules. Tropiclo- Rhipido- Spirifer Del- Camaro- Procluc- Cyprileptus. mella. marcyi. thyris. toochia. · tella. cardella. 

-----------·-------1----1--------------------- Apalachin.................................................... 63 7 2 3 10 11 11 7 

~~;h~\;~~·:::::::::::::::::::::::::::::::::::::::::::::::::::::: ig ~ ~ 2g ~~ i~ !g 1~ Harford. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • . . . . . . . . . . . . . . . . . . . . . . . 282 12 34 3 6 48 63 30 

Ithaca........................................................ 152 1 2 1 5 16 68 6 

~~,~~~?.; ::::::::::::::::::: ::::::::::::::::::::::: :~: ::::::::: gg ........ ~ ........ -~· ...... -~~- ~ 2~ ~ 6 

b~~~~~~!a:::::::::::::::::::::::::::::::::::::::::::::::::::::: __ f~-~ __ _~ ., ..... ~~. ····---~~. ····---~~. __ i_~ _· __ ~-~ ___ ~: 

1, 514 69 88 79 131 214 552 116 

In the fu'St colmnn the total nun1ber of separate faun~1les obtained frmn each quadrangle 

is indicated. In the other columns are given the !lumbers of faunules fron1 each quadrangle 

containing the particular genus indicated at the head of the column. Attention is CGtlled to 

the fact that the faunules under each genus are not necessarily different faunules, for many 

faunules contain most of the genera named, and that there is no significance to the cross totals 

by quadrangles. 

The faunules of the above· table are separate samples of the fossil contents of the rocks. 

They furnish, of course, very 1neager statistics of the total fauna living at the ti1ne the strata 

in whi.ch they were obtained were being laid down, and of course they do not include species 

which did not live in the area at the particular stage of time they severally represent. Nevertheless, I believe that they furnish fuller statistics than have ever been gathered on this continent for a like section of Paleozoic rocks covering even so small an area as is here represented. 

They are the best evidence available, and the problem is to ascertain if they are 'capable of 

giving any positive ·evidence regarding the fauna] succession which. topk place during thiS 

portion of Devonian ti1ne. ' 

· The last four genera named in the table are those that are shown, .by examinatio.n of the 

several faunules in which the first three (diagnostic) genera are found, to be more frequently 

associated with these three than are any others, and also to be present in about 50 per cent of 

the sample faunules giving indication of these Hamiltonian species. 

In the general study of the fai1nules I have considered the presence of two or three of the 

five species, Tropidoleptus carinatus, Rhipidomella vanuxemi, Spirifer marcyi, Delthyris mesicostalis, and OyJJricarcleZZa bellistriata, as significant of the recurrent fauna, and' have listed the 

faunules thus· indicated and have given thmn special study. 
74 RECURRENT TROPIDOLEPTUS ZONES IN NEW YORK. 

As already stated, in several cases the separate faunules collected from the same section 

and containing the same species, but a few feet apart, have been as~ociated together as a single 

representation of the recurrent· zones. The final ·samples, 63 in all, have been given serial 

numqers, (see p. 10), and the same· numbers have been applied to the list of species given on 

page 32. Examinat~on shows that in 19 of the 63 zones (Nos. 16, 29, 33; 34, 36, 38, 39, 53, 55, 

56, 24, 32, 41, 2, 15, 18, 21, 58, and .59) the three diagnostic genera Tropidoleptus, Rhipidon1ella, 

and Spirifer marcyi are found together. In 24 others (Nos: 26, 27, 28, 30, 35, 40, 52, 54, 60, 

3, 5, 9, 22, 42, 1, 10, 13, 14, 17, 19, 20, 25, 43, and 63) two of the diagnostic genera are associated. Thus in 43 of the 63 recurrent faunules at least 2 of the diagnostic genera are present. 

All but 1 of the remaining 20 contain at least one of the three diagnostic genera and other 

genera and species in sufficient number to indicate the presence of the same fauna. A single 

faunule (4) actually C?ntains none of the diagnostic genera, but it contains both Gypricardella 

bellistriata and Delthyris mesicostalis and is at the position in the section appropriate for zone 

No. 3. It is also observed that in the Chemung Gypricardella bellistr:iata has been chiefly 

found only in the recurrent zones. The faunule has therefore been placed in the list. It is 

on this basis of facts that the recurrent Tropidoleptus zones Nos. 1, 2, and 3 are discriminated. 

These zones, as already described, are situated (1) in the Portage formation, near the top 

of the Enfield shale member, (2) in the Chemungformation in the lower half of the Cayuta 

shale member; and (3) in the .Chemung at the extreme top of the Cayuta member. At no 

other places above the Ithaca shale member of the Portage formation have any two or three 

of the generic types been found together. Tropidoleptus and Rhipidomella are not known to 

occur in the sections in the area except at one of these three zones; and Spirifer marcyi, with five 

possible exceptions, is not known to occur except within a few feet either below or above the 

horizon of the other two genera. The fiye doubtful occurrences out of a total of seventy-nine 

are all above the base of the Chemung, and the doubt regarding -them arises from lack of evidence for determining their exact correlation. 

In the sample faunules selected for study one or two may on .research be found to be wrongly 

included, error having possibly arisen through the fact that I originally regarded Cypricardella 

and Delthyris· as equally certain indexes of this recurrent fauna with Tropidoleptus, Rhipidomella, 

and Spirijer marcyi.. On final array of the evidence I found the presence of those two genera 

to be riot positively diagnostic of these zones, although intimately associated with them, and I 

may have failed to weed out some samples included on their evidence. 

· In regard to Delthyris the eVidence can be given only approximately at the present time, 

because of the difficulty of determining ·positively whether certain specimens examined are 

Delthyris .or Spirifer pennatus posterus, as has been already explained in the discussion of the 

genus Delthyris (seep. 65) .. 

Thus the evidence shows that there are three well-defined paleontologic ·zones (Nos. 1, 2, 

and 3), which are distinguished from other fossiliferous zones by the presence of the genera 

Tropidoleptus and Rhipidomella and the species Spirijer marcyi. The lower zone (zone No. 1) 

is further distinguished as the place in the sequence of strata at which the genus D.elthyris first 

appears in the fauna above the Hamilton formation. Delthyris is a. dominant associate with 

the other three genera after it appears, but it is not restricted to the recurrent zones as defined. 

ASSOCIATED SPECIES. 

Quite a number of other species in the faunal lists may be traced more or less directly to 

the I-Iamilton· fauna for their direct ancestors. The following may be mentioned: 

Pleurotomaria capillaria. 

Paheoneilo bisulcata. 

Amboccelia umbonata. 

Modiomorpha cf. concentrica. 

M. cf. sublata. 

Macrocheilina macrostoma. 

A viculopecten priri.ceps. 

Bellerophon brevilineatus. 

Cyrtina hamil tonensis. 

Phthonia cylindrica. 

Modiella pygm::ea. 

Limoptera macroptera. 

Spirifer :fimbriatus. 

Phacops ran a. 

Macrodon hamiltonire. 

Glyptodesma erectum. • 
EXISTENCE OF THE ZONES. 75 

Any attempt, however, to trace such spe~ies to the Hamilton discloses many others belonging to genera which have closely allied species in the Hamilton and which occur not only in 

the particular recurrent zones but also n1ore or less· continuously throughout the intervening 

strata of the Upper Deyonian. 

EVIDENCE THAT THE FAUNA IS RECURRENT. 

CRITERIA OF l"tECURRENCE. 

Proof of recurrence is more complex and difficult than would at first seem. It is very 

con1mon to ftnd the same genera or species in successive fossiliferous zones in . a continuous 

section of rock strata. But such occurrence does not necessarily imply that the ·faunas recur 

in· the section; it is more rationally·explained as evidence of continuance of the fauna, its nonoccurrence in the intervening rocks being ascribed to interruptions of the record from one 

cause or another. Recurrence, as used in this paper, implies· (1) the temporary withdrawaL 

of the fauna and its replacement by another fauna, and (2) its later return to the area of fust 

occupation. Both of these events have been established 41 regard to the Tropidoleptus faul).a. 

WITHDRAWAL OF THE FAUNA. 

The withdrawal of the fauna is shown positively by the restriction of the three generic 

groups Tropidoleptus, Rhipidomella, and Spirijer marcyi to the particular zones and by their 

entire absence from the faunas between tlH3 zones (although those faunas have some other species ' 

in common and as faunas have a very similar general composition). Faunal life did not cease 

between the zones; on the contrary,. it was abundant and, . to casual observation, shows no 

break or noticeable change in general composition· as it mounts in the strata. Nevertheless 

these three generic types appear together at certain horizons in the sections over the whole 

area, and are absent at all other horizons. l\1oreover, they appear in these zones not as single 

or rare specimens but in abundance. 

UETURN OF THE FAUNA. 

ABSENCE OF THE GENE.RAL FAUNA IN THE TROPIDOLEPTUS ZONES. 

Regarding the interruption of the general fauna the evidence is certain. The species 

which constitute the dominant complexion of the fauna below and above the recurrent zones 

are generally lacking in the zones delineated by the diagnostic genera. But this is a general 

statement, and to make it· particular or to infer that the general fauna has entirely withdrawn 

from the basin during the deposition of the recurrent zones would require deeper and more 

exhaustive study than I have been able to give. The present ~ollected evidence consists only 

of a lot of sample faunules obtained from widely separated places and from widely separated 

horizons. Not only is the content of each local faunule extremely small, but the limiting causes 

are diverse. Only a handful of specimens was obtained from each fossiliferous ledge examined, 

and the ledge contained only such species as were accidentally buried and preserved at the 

particular square foot or so of the bottom examined. Hence not only the accident of finding 

and collecting but the imperfection of expression of the charactedstics of the living fauna by 

the few preserved fossils make the testimony imperfect. Moreover, the relative rarity and 

abundance of the individuals of the several species in the fauna and their relation to the particular conditions of environment at the points from which the samples came make, the samples 

extremely fortuitous as expressions of the total composition of the then living faunas. 

Again, the possible modification of the species and the adjustment of their variable characters to differences in environment and the evolutional changes associated with successive 

stages of the race history complicate the problem; so that a slight deviation from the type 

form makes ·the discrimination of species uncertain. The study of the successive samples of 

nny of the genera herein brought together .indicate very strongly the .importance of fluctuating 

vnriatioi1. The investigations lead me to believe that the present definitions of many species 
,, 

76 RECURRENT TROPIDOLEPTUS ZONES IN NEW YORK. 

are entirely artificial. Each genus must be studied in connection with the fluctuating vanations normal to the several representatives living together in a connected area at the same time 

before'the differences expressed by successive appearances of the race can be pr9perly interpreted. 

For the above reasons ~t has seemed to me useless to attempt by a preliminary listing of 

species as at present ·discriminated to prove either connection or nonconnection between the 

faunas of these particular zones and the general fauna of the Portage or the Chemung formation . 

. Such relationship can be established, if at ali, only after thorough study of all the evidence 

that can be gathered regarding the morphologic behavior of each single genus in relation both 

to its geographic distribution and its stratigraphic sequence. 

IDENTITY OF THE RETURNING FAUNA. 

Range of fluctuation.-The variations expressed in the recurrent zones by the several 

genera which constitute a dominant part in the faunal composition fall within the differing 

degrees of plasticity expressed by them in the Hamil ton. 

Tropidoleptus, though showing slight n9rmal variational fluctuation, is remarkably persistent in form; specimens from the uppermost zone (No. 3) present rio characters for distinguishing t~e~ from Tropidoleptus carinatus ·from the Hamilton, where it is an exceedingly 

common spec1es. , 

Rhipidomell!l, to which I have given exhaustive critical study, shows the same remarkable persistence in the nature and extent of its normal fluctuatmg characters; exam:ination of 

the specific differences by which the Hamilton representatives are differentiated in literature 

show these fluctuations persisting in the higher representatives of the recurrent :iones. 

Spirifer marcyi expresses the same persistence in fluctuation, not only :in the generic characters but in the so-called specific .details. At each -stage the representatives of the species 

continued plastic; their fluctuating variations continued without settling down into any permanent specific combination up to the top of the Cayuta member of the Chemung, although 

a mutational character occasionally appeared which later assumed generic rank. A few specimens in the zones Nos. 1 and2'show a rudimentary syrinx. Such specimens are associated with 

others in the same faunule like them· in other respects but with no perceptible trace of the 

syrinx. A full study of the progressive assumption of, this character is under investigation, 

·and, so far as investigations have gone, appears to disclose a genuine evolution of a character 

regarded in literature as of generic rank. · The other charac.ters of Spirijer marcyi cont:inue in 

the majority of specimens; the earlier syrinx-bearing forms are rare and appear at widely separate localities, and in these early forms the syrinx is rudimentary. 

All three of these generic forms (irrespective of the mutation expressed by the syrinx of 

Spirifer marcyi) show a high degree of constancy, both in the generic characters and in those 

plastic characters by which the variational capabilities of the race are expressed, during all that · 

portion of the history. of the races here under investigation. In this constancy of characters 

the three contrast with the other. associated common representatives of the fauna. 

Delthyris begins (after the Hamilton) to appear in the faunules of zone No. 1 (Enfield 

member of Portage). Specimens from that zone ar~ generally less developed both in size and 

in. the dom:inant characters of the race than are the later expressions of the race in the Chemung; 

and the species in_ the higher Cayuta member and in the Wellsburg member express decided 

differences from the earlier forms. These facts I have observed ill the collections but have not 

made the necessary critical examination to enable me to state then1 in de:finite scientific form. 

Some specimens from the faunules from zone No. 1 differ extremely little from Delthyris consobrinus of the Hamilton. Several such faunules contain also other specimens not readily 

distinguishable from the typical Spirifer pennatus of the liamilton; in .these latter there iS no 

trace in the pedicle valve of the median septum characteristic of Delthyris. These facts give 

re~son for the hypothesis that such faunules represent a pure recurrence of a I-Ian1ilton fauna. 

But another fact comes in to vitiate this interpretation. The species Spirifer pennatus posterus 

(which in the.original clescr.iptio:t;I was confused with,~pirifer ( = Delthyris) mesicostalis), is found 

abundantly in the· Ithaca fauna; that is, in the lower Portage below the zone (No. 1) in the 
EXISTENCE OF THE ZONES. 77 

upper part of the Enfield n1e1nber of tho Portage. In no specimens of this Ithaca species has 

there been. observed a definite septun1 in the interior of the pedicle valve,· although there is 

always a faint line separating the muscular scars on the interior of the sinus of that value. 

The abundant presence of this species, Spirifer pennatus posterus, below the Tropidoleptus 

zone No. l, both in the typical Ithfl,ca fauna and (in the IIarford quadrangle) in the higher 

fn.una in the strata succeeding the place of the Oneonta sandstone in the lower stages of the 

En:Held, suggests another hypothesis, namely, that the Delthyris of the zone No. 1 and of subsequent Chennn1g is a direct evolution, in place, from the Spirijer pennatus posterus. The solution 

of this. problmn will require a close, minute, critical exan1ination of all the evidence, and this 

I hn.ve not yet been able to give. The investigation of these facts offers a fine opportunity to 

sotne student, for they see1n to· express a definite evolutional history. 

The peculiarity which bears directly on the present argument is the continuance of the 

essentially unchanged form of Delthyris in the general fauna, after its apparent first arrival 

into the area, iii association with its evolutional modification. The other three genera (Tropidoleptus, Hhipidomella, and~ Spirifer marcyi) :('mci expression only in the restricted zones. The 

ge.n.us Deltltyris, although coming in with the fu·st ·of the zones, did not withdraw, but rmnained 

upon. the ground. The inference is that something happened which terminated ~he existence 

of the tlll'ee genertt but did not drive out Delthyris. The remaining of Delthyris, after the 

departure of Tropidoleptus, Hhipidomella, and Spirijer marcyi, ·is evidently ~ssociatecl with some 

changed condition. of environment. The three forms which exhibit rigid adherence to their· 

ai1cestral1nodes of development suddenly came and as suddenly departed, but the other form, 

Delthyris, suddenly appears, remains on the ground, and changes its fornis. It is ·probable 

that the first three groups of species were closely adjusted to a narrow range of mnironmental 

conditions and nugratecl with then1; the fourth group, having its origin in a region of restricted 

cond.itions, 1noved in with the other three, but was capab]e of adjustment to the new conditions 

after the withdrawal of the particular nonnal conditions under which it previously lived. Tills 

argmnent, though hypothetical, agrees with the general evidence, for it assumes that an actual 

recurrence of certain, at present· unknown, conditions of environment was the cause of the 

appeara.nce i1\ the sections of that peculiar combination of species called the recurrent Tropidoleptus fauna. 

Racial continuity.-The thrQe generic forms so diagnostic of the recttiTent zones are each of 

thein characteristic representfLtives of the normal I-Iamilton fauna. Tropidoleptus and H.hipidomella are abundant throughout the whole I-:Iamilton formation, and Spirijer marcyi abundant 

in. some of. the beds of the upper I-Iamilton. Their identity wjth tlie I-Iamilton forn1s is established by their persistence in retu.ining not only generic but fluctuating variations, for it must be 

borne in, n1ind that the continuity of a race is established only by evidence of continuous reproduction of the same characters. The instant modification of characters begins in a series of 

extinct organisn1s the thread of continuity is broken. This is the reason why it is necessary to 

· deal with so-called generic characters first.· It is essential to establish genetic continuity of the 

representatives of the race before it is practicable to discuss the modifications which the race 

has undergone in its genetic 'history. I-Ierein lies the great significance of ~stablishing the 

recurrence of a fauna. It is a simple n;:t.atter to d.iscover differences between representatjves of 

the san1e genus at successive stages in the geologic column; but if those difference's are found 

to be absolute (that is, if a species in one zone is found constantly to develop a character not 

· expressed by the related species of a lower zone) then the question as to whether they are genetically 

continuous arises. The reason for the uncertainty lies in the lack of evidence as to whether the 

new species lived in some other region conten1poraneously with the first species and was intro- . 

duced by migration, or was djrectly evolved, in place, by evolut.ionary n1odification of charact~rs from the earlier species. 

It is illogical to assu1ne that the particular n1odification has taken place bJ direct genetic 

evolution mitil it has been clearly established that faunal continuity has existed. As faunal 

contii1uity CHJl be es~ablished only upon evidence of repetition of the san1e characters, it becomes 
78 RECURRENT TROPIDOLEPTUS ZONES IN NEvV YORK. 

necessary to trace a generic group upward through the aeries of deposits; because the fluctuation 

shown by each such generic group, and expressed by the representatives of the group living 

together in the same faunule, includes characters which have been used in discriminating the 

separate species within the genus. Any combination of characters which is possible to a genus 

at one stage of its existence (aa expressed by the individuals living at that one stage under 

similar environmental conditions and as recorded by the· fossils of a single faunule) must be 

considered as possible of expression in the fossils of a later stage without disturbance of the 

genetic continuity of ~he race. On the other hand, any addition to or subtraction from the 

characters expressed at one stage which makes its appearance in the forms at a higher stage 

may be mark of a separate group of the genus-separate in its adjustment to environmental 

conditions arid separate in its areal distribution. And such separateness may date back to a 

point in racial history earlier than the first stage used in the comparisons. The chief problem, · 

therefore, is to trace racial continuity. 

Theor~tically, all the representatives of a genus may be supposed to have a. coinmon ultimate 

origin. At each stage in ~heir history a certain amount of diversity in form is theoretically 

assumed to be normal to the race at that stage of its evolution. Practically, the amplitude 

of such diversity of form is assumed to be expressed by the group of individuals living together 

at the sam~ stage and thus by the fossils found in one faunule. In tracing the continuity, 

therefore, into successive zones it is not specific identity that it is essential to establish (for 

specific identity is not required among the .representatives of the single faunule); it is inclusion 

within the amplitude of fluctuation of characters expressed by all the individuals representing 

the genus in the particular faunule on which the conception of the racial integrity at that 

particular stage in its history must be based. If such a group of individuals is found to consist 

of separate subgroups of individuals not connected by fluctuating variation, it is necessary to 

restrict the generic group to that subgroup, no matter what it is called in descriptive literature. 

Thus, in the present discussion and for the purposes of this discrimination of natural groups of. 

individuals, Spirifer marcyi is a natural group of individuals having fluctuating -variation; 

just as Tropidoleptus or Rhipidomella are natural groups expressing themselves in fluctuating 

variations at each stage under investigation. Other spirifera (such as Reticularia }revis, Spirijer 

pennatus posterus, Spirifer mesistrialis, and Spirifer disjunctus'j, which in literature are classified 

as species, possess distinguishing characters not possessed by the others. The question as to 

whether theae distinctive characters· are of specific or generic rank does not· enter. The diagnostic characters of each" species" may be fluctuating characters for the individuals constituting 

the "specific" group to which they belong, or they may appear to be nonflu~tuating; in either 

case, so long as the amplitude of their fluctuation for the particular stage does not lap over the 

amplitude of fluctuation of similar characters for the other" species," the individuals possessing 

them constitute essentially one generic group. Evolutionally and morphologically the only 

valid distinction is as to the presence or absence of a character. For purposes of classification 

specific, generic, or ordinal rank may be ascribed -to specimens possessing this, that, or the 

other character; but in an attempt to trace genetic lines all individuals possessing a particular 

character, even in a rudimentary condition, must be positively distinguished from all forms 

not possessing it. Eyery such character becomes a means of discrimination between individuals, however fluctuating in size or form it may be in the group of individuals holding it. 

T~e only limit separating one continuous race of individuals from another must be drawn in 

terms of such positive characters. The line of distinction must be drawn on the basis of actual 

absence or actual'presence of a distinct definable character, and not on fluctuating characters 

except where the gap in the amplitude becomes itself a definite boundary separating distinct 

groups of individuals. · 

On the Darwinian hypothesis that specific distinotion arise.:; by fixing in one part of a race 

the limit of fluctuation of a character, rac\al groups must be conceived to break up into subgroups 

which do not mix with each other. On this hypothesis the formation of a new species will 

be expressed in fossil specimens by the definite appearance at some particular geologic stage 

of a gap in the fluctuating characters for a series of individuals living together at the same 
OSCILLATION OF THE RECURRENT FAUNA~ 79 

tin1e a3 found expressed in a single faunule. The exisi:.ence of such a gn.p muat be expressed 

in the terms I have outlined and will be shown by the different degrees of development of some 

co1n1non part. Until, however, the linrit of t1w fluctuation can be discerned no evidence of 

nonm.ix.ing of the two subgroups can be established. Hence, unless the gap in the fluctuating 

series continues to be exhibited in later stages of the racial history no "specific" grouping 

can be established. And when the gap is thus shown to be permanently established the difference is indistinguishable fron1 the differences called "generic," so far as it can be defmed in 

tern1s of morphology. The difference, therefore, between "specific" and "generic" becomes 

not one of facts capable of observation and of definition in terms of n1orphology, but one of 

theoretieal interpretation of facts. 

CONCLUSIONS AS TO RECURRENCE. 

The establishment of the fact that the three zones under consideration contain at least 

three well-defined generic group·s which are identical for the several zones and for the Hamilton 

fornu1.tion gives a rational ground for the theory of recurrence. No other theory thn.t I can 

at present formulate will explain the presence of these generic groups in these· particular zones 

and their absence elsewhere in the formations above the I-Iamilton in which these zones 

occur. And this reasonable basis for the general theory of recurrent zones having been 

established, it 1nay reasonably be extended to include the zone near -the base of the Ithaca 

n1e1nber on the basis of the occasional discovery there of two at least of the diagnostic genera.:_ 

Tropidoleptus and Rhipidomella. 

STU.ATIGU.APHIC EXTENT OF THE ZONES. 

The exact stratigraphic limits of the faunules at each of the zones is not yet certain. The 

Tropidoleptus zone No.3 appears to be limited in range to "less than 10 feet thickness of strata. 

The zone No. 2 in son1e outcrops appears to be also narrow, but in the section at Waverly it 

seen1s to c01nprise several thin zones spaced at intervals of 10 to 20 feet. In ~he I-I_arford 

quadrangle the recurrent faunule of zone No. 1 has been detected at three or four separate 

horizons ranging through at least 100 feet, although in 'the section at the typical locality (Van 

Etten) it appears t? be_not over 20 feet thick. · 

OSCILLATION OF THE RECURRENT F.AUN.A. 

The facts see1n to .indicate that the introduction of the particular fauna associated with 

Tropidoleptus wn.s not due to a sudden change of conditions, lasting for a brief tiine only and 

as suddenly withdrawn. It seen1s rather to have been asso'ciated with s01ne gradual change 

in the conditions affecting the general highway by which this foreign type of fauna found congenial access to the area-a change \vhich opened a ready passage from the foreign center of 

distribution. This opening reached its clin1ax at the point in tin1e when the conditions appropriate to the life of this (Tropidoleptus) fauna dominated those nor1nal to the previous occupants 

of the area. The two sets of environ1nental conditions for a long time oscillated back and forth 

and fi.nt1.lly the conditions n.ppropriate to the foreign fauna were wholly withdrawn, the recurrent 

faun11. retreated, and the normal fauna again occupied the area. 

i This .is about as far as the -recurrence· hypothesis Qan be elaborated on the basis of the 

actual collected facts. Very n1any othe~ suggestions arise, to scientifically establish wlrich 

the ground n1ust be further examined and new fa:cts gathered. 

It is not to be understood tl~at the fauna of the seas recorded by the zones totally differed 

fro:m that of the seas recorded by the strata above and below the zones. The facts signify 

rather that the succession of the 1nar.ine faunas was clue, not to a uniform continuous progression of conditions, geographic and geologic, but rather to an oscillation back and forth of opposite' 

or contrasted conditions. 

The recurrent zones are expressions of the climacteric or nodal po~ts in .these oscillations. 

For long periods prior to tlie appearance of the diagnostic genera the conditions were leading 

up to those essential to their existence. During this preparatory period one after another of 
80 RECURRENT TROPIDOLEPTUS ZONES iN NEW YORK. 

the n1ore hardy species reac~ed the area. In the sa1ne manner, after the climacteric point 

was past and the dir~ction in change of conditions was reversed, one and another of the species 

of the fauna was cut off by adverse conditions of- environment and other Inore hardy species 

continued to live. Some of the more hardy, with the changed conditions, exhibited their 

hardiness by modifying their characters, and tlwse rmnained after the alternate set of conditions 

had changed the composition of the fauna. · 

To n1ake the problem simple: Suppose the two sets of faunas were sin1ply Arctic and tropical 

faunas, such as are now seen along the eastern coast of An1erica. Suppose the difference in the 

faunas to be detennined primarily by the ten1perature of the water. Geologic changes of a 

general character n1ight take place, resulting in the gradual dominance of the cold waters from 

the Arctic Seas until the total inhabitable marine waters at a particular shore (say Nova Scotia) 

had become as cold as those of the Arctic regions. Not only would the faunal life of the shore 

contain species peculiar to the Arctic faunas, but, finally, it would cease to include all species 

of, the more southern 'faunas not adjustable to cold waters. During the process of change 

n1embers of the Arctic fauna capable of a wide range of ternperature would fron1 tin1e to tin1e 

migrate to the area, but the strictly Arctic species would not enter in abundance and would' 

not dom.inatethe fauna till full Arctic conditions prevailed throughout the year. 

After Arctic conditions had reached a clin1ax, suppose geologic changes should occur that 

would reverse the process and gradually throw warm waters farther and farther north. The 

tin1e can be in1agined when the conditions off Cape I-Iatteras would prevail off the shores of 

Nova Scotia. The effect on the fauna wol1ld be gradual if the geologic changes were gradual, 

and when the change had become such as fully to replace the Arctic waters by those having 

Hatteras conditions of ten1perature the fauna living (and therefore recorded in the deposits 

n1ade) would be of the Hatteras type. 

This is a .si1nple illustration of what might be expressed by the fossil faunas under the 

co1nplex conditions of change existing during the latter half of Devonian time in the Watkins 

Glen and Catatonk quadrangles. The recurrent faunas den10nstrate some such oscillation in 

envLrorunental coi1ditions, although the cause and nature of the oscillation is at present 

unknown. 

SIGNIFICANCE OF RECURRENT FAUNAS. 

DIASTROPHISM. 

. . 

The wide signincance of this study of fossil faunas in interpreting the past geologic history 

of the globe is now appreciable.. Other phenomena have led geologists too believe that the 

particular relations between land and sea now determining the geographic conditions of t4e 

earth's surface are but temporary. The continental n1ass~s of land are in great part composed 

·of materials laid down in the ocean and arranged by processes now chiefly performed below the 

surface. Thus it is necessary to assume that the lands have been elevated by diastrophic movements above the position, relative to ocean level, which they originally occupied. At first 

geologists imagined that the ocea1~ had retreated; but wider study made it ev1dent that there 

is no place on the earth or in it to \vhich the waters could retreat. The logical explanation of 

cliange 0f altitude between the surface of the rock and the surface of the ocean is that the general 

ocean surface is geologically the more stable of the two. The widely accepted and consistent 

hypothesis is that continental elevations have been associated with corresponding depressions 

of the ocean pottoms so far as their vertical relation to the ocean surface is concerned. The 

depth of the ocean basins has increased as their surface area has decreased in order to preserve 

the cubic capacity of the ocean constant. Further study of the problem, as an earth.problen1, 

has develop~d the fact that the elevation of continental 1nasses has not been uniform either 

geographically or chronologically. At the present ti1ne some parts of the continents are rising 

and other parts sinking: , 

One of the most important results of these studies has been the framing of a hypothesis 

by which the events in the geologic history are directly ascribed to htovements upward and 

downward of- the solidified earth crust in 1·elation to sea ·level. According to this hypothesis 
'I 

SIGNIFICANCE OF RECURRENT FAUNAS. 81 

transgression of the sea over the land surfa~e s}lows that the land is sinking; whereas its withdrawal from tbe land, thus ~xtending the ~urface seaward, shows that the land is rising. 

GEOLOGIC EVIDENCES OF DIASTROPHISM. 

Evidence of such transgression and retreat (and therefore evidence of diastrophic Inovements) is expressed, in a general way, by the sedin1entary rocks formed during their progress. 

The Sl_iCCession of the physical characters of. the sedimentary deposits recorded in a particular 

·rock section indicates whether the sea was transgressing upon the land or was withdrawing. 

The interpretation of the fn.ct~ is based on the general law that the coarser the sediments the 

nearer they niust be to their place of origin or formation under unifonn conditions of sediinentation. Thus, in general, a section containing at the botton1 coarse congl01nerates followed by 

sn.nds with finer and finer· grain indicates increas~ng depth of the waters i~1 which the sediments 

were deposited/ and therefore indicates a gradual increase, during the period of the record, in 

the distance fr01n the point where the section was made to the then existing margin of the sea 

in ,which the sediments were being deposited. 

If the order of the del)osits is reversed (that is, if the physical size of the particles making 

up the rock increases progressively from the bottom up) the presumption is strong that during 

the period of sedin1entation the sea was becoming shallow, or the pln.ce of deposition was becoming nen.rer to the land with progress of time. 

All through the geologic columns of all regions such changes in the sediments have been 

observed, the change in character of the sedin1ents indicating in 'some places one kind of diastrophism and in some places another. It is thus certain that din.strophic 1novements have been 

taking place as the sedi1nentn.ry rocks have been formed. 

TIME RELATIONS OF DIASTROPHISM. 

LITHOLOGIC EVIDENCE. 

The fact of diastrophis1n is unquestioned, but the deternlination of the position of the 

shore at any particular geologic tirrie necessitates correlation in time of the records at each 

. particular locality. Increasing depth n1ay be expressed by the lithologic character of the 

sediments at locality A for' a time sufficient for the accumulation of 1,000 feet of sediments; 

and similar increasing depth, with the san1e accumulation of sediments, may be shown at 

locality ·B, 50 miles to the north of A; and yet nothing in the character of the sedi1nents alone 

can certify that the diastrophic movements recorded took place at the same time for the two 

localities. The physical composition, of the sediments is determined by the land from which 

the n1aterials are derived by erosion, and if the rocks are the same it makes no difference at 

what geologic age they are ground up and deposited. The lithologic character of sediments, 

forn1ed at sin1ilar rates, by sinlilar modes of erosion; and under si1nilar conditions .of transportation and seclimentation1 will be the same. On the other hand, if the sources of the materials 

are different the lithologic character of sedimentary rocks deposited under like condi~ions and 

at the san1e time will differ. The chemical constitution, also, of sedimentary rocks, is determined 

by the chen1ical constitution of the preexisting rock n1aterial out of which the sediments were 

formed; and this ln.w is constant for all stages ·of geologic time. Also, the physical size and 

nrrangen1ent of the particles of sedi~1entary rock are determined by the physical properties of ' 

the original1naterial and their weight relative to the specific gravity of water, for the general 

·laws of erosion, transportation, and s·edinientation have been theoretically alike. in their 

operation and effects through all geologic ages fr01n the Cambrian up to the present time. 

Although it is found expedient in classifying rock formations to apply nmnes on the basis of 

lithologic unifonnity., it is :unscientific to n1aintain that such uniforn1ity in1plies contemporaneity o~ deposition of the sedin1ents 1naking up the fornl!).tions. Conten1poraneity, indeed, may 

1 Or it may moan changes in climate or in currents or in tho topography or lithology of tho adjacent land surface which is being eroded. 

67437°-N o. 79-13-6 

' 
J 

82 RECURRENT TROPIDOLEPTUS ZONES· IN NEW YORK. 

be expressed by geographic diversity of sedimentation, for sedin1entation at different distances 

beyond the coast and at diff~rent 'depths could scarcely be uniform. .Approximate uniformity 

of the physical constitution of the sediments might be expected to prevail for long distances 

parallel to the original coast line; and if the sinking of the 1and kept pace with the deposit of 

the sediments this uniformity of physical constitution might continue for an indefinite period of 

time. Uniformity in the lithologic character of the sediments parallel to a shore line may 

roughly signify contemporaneity of deposition, but uniformity at right angles to a shore line 

suggests progressive change in level or diastrophism. Conversely, it follows that it is only where 

uniformity in the physical character of the sediments can be ·shown by independent evidence 

to extend at right angles to the shore line t}J.at it can be interpreted as evidence of diastrophis~. 

FAUNAL EVIDENCE. 

It is because of the Impossibility thus pointed out of deriving fron1 the lithologic characters of sedimentary rocks alone any positive in<;lication of their geologic age, that the geologist 

is obliged to consult the evidence furnished by fossils in order to determine not only the fact 

but the character of the diastrophism. The faunas of the recurrent zones, herein discussed, 

give positive evidence not only as to the stage in geologic history at which the zones were 

deposited but also by their difference from the faunas contained in the consecutive beds strongly 

suggest general orogenic movements such as the geologist characterizes by the term diastroph~sm. From the Hamilton up to the Chemung for this region a gradual but intermittent 

change takes place from fine mud shales to moderately coarse sandstone, suggesting a gradual 

shallowing of the seas in which they were deposited. · This- difference in, lithologic characters 

of the sediments took place at an earlier date in the eastern part of the area than in the 

western part. But the establishmeJ;lt of the time relations requires the evidence of fossils. 

In figure 2 (p. 24) an oblique line/ indicated by the words "Base of Chemung type of sediment," is drawn from the base line of the Cayuta member of the Chemung formation to the 

top of the Oneonta sandstone. This line is an attempt to express, by current methods of 

classification and mapping, the actual facts regarding the contemporaneity of geologic events 

in the area under discussion, as brought out by a close inspection of the fossil faunas. . 

The,facts were first outlined in 1885. 1 I then stated that the Catskill type of sedimentation 

began in the eastern part of the State immediately above the Hamilton 'f'o.rmation as expressed 

in terms of the faunas. In the middle part of the State this type of sediment did not appear 

until after Portage faunas had n1ade their record in the sediments, and in the west~rn part 

of the State not till after the Chemung faunas had received full expression. Catskill sedimentation, it may be explained, is a term indicating a condition of the environment which 

affected the general nature of the fossil faunas. In the Catskill sedin1ents almost all fossil 

evidence of marine conditions )las disappeared, leaving the rocks in· sharp contrast with the 

ordinary Upper Devonian sediments ·holding typical marine faunas. 

CORRELATION OF LITHOLOGIC AND FAUNAL INDICATION-S. 

In the Watkins Glen and Catatonk quadrangles the same conditions are· expressed by the 

general marine faunas among sediments in which the lithologic differences are slight. The 

oblique line in figure 2 (p. 24) is an attempt to give the field-geologist a lithologic 1neans of recognizing the passage from the Portage to the Chemung in the eastern se~tions where by paleontologic 

evidence the passage from the Portage fauna to the Chen1ung fauna does not take place until 

higher up in the section. · 

The geologist who is accustomed to trace the outcrops of a formation across the country 

by means o.f uniformity of sediments is thus given a guide by which he may recognize in the 

eastern part of the State the base of the Chemung as it is defined in the western part (fig. 2); 

and the diagram points out that the passage .is geologically lower (or earlier) at the east than 

at the west. The basis of this determination of historic stage in geologic events is the p'aleon- 0 

tologic record; the figure is designed to furnish a concrete example 9f the problem for intelligent 

discussion. 

1 On the classification of the Upper Devonian: Proc. Am. Assoc. Adv. Sci., vol. 34, 1885, pp. 222-234, with chart. 

r. 
SIGNIFICANCE OF RECURRENT FAUNAS. 83 

CONTEMPORANEITY OF DEPOSITION. 

LITHOLOGIC EVIDENCE. 

I-Ieretofore horizons expi'essed by geologic formations have been accepted as synonymous 

with epochs of geologic ti1ne. In the discussion of proble1ns of paleogeography it is important 

to note that this is true only in a general way. The comparison of fine shales with conglomerates at once suggests wide differences in the conditions of sedlinentation which may be readily 

interpreted as resulting fron1 differences in distance frmn the original source of the sediments. 

But the laws of diastrophis1n and their use in reconstructing the geography of the surface require 

knowledge not only of the existence of changed or changing conditions but also knowledge as 

to the direction in which the change is advancing. 

To interpret direction it is ess.ential to establish contempora:r:eity of the records compared. 

Two localities n1ay expose outcrops of a sin1ilar conglon1erate, but it is necessary to show that 

they are cont01nporaneous to prove that a line connecting t.hem expresses a shore line of the 

se·a of the tune when .they were forn1ed. Everywhere it is to the fossils that reference must be 

1nad.e for direct evidence of cont01nporaneity. And the lines by which paleogeographic lands 

are outlined have ~·ationn.l n1eaning only so far as the rocks along them are supposed to be 

contmnporan.eous. 

FAUNAL EVIDENCE. 

The prlinary reasons for supposing that fossils are capable of testifying positively as to the 

geologic age of the deposits holding th01n is the observed change in the fossil contents of the 

rocks in successive strata. This change is observed not only in the 1norphologic characters of 

the fossils but in the cmnposition of the faunas. 

COM·POSITION OF FAUNAS. 

The change in representatives of the san1e genus or species is not so rapid nor so uniforn1ly 

expressed as is the change in the cmnbination of a·ssociated fossils n1aking up faunules of the 

successive zones in the rocks. 

The faunal differences which strike the eye of the field geologist in contrasting· fossiliferous 

slabs frmn two different for1nations are generally generic and not. specific. The untrained 

observer is not likely to notice the slight modifications of forn1 in the san1e genus associated 

with successive stages in its evolutional history; and a great n1any 1narine invertebrates of the 

Paleozoic representatives of the smne generic race, separated by several 'formations fron1 each 

other, Jnight easily be confused and regarded as the smne except by an expert paleontologist. 

But n10difications of the fauna, as expressed by changes in the relative abundance, the presence, 

and the absence of particular fon~1s; and by the n1ore or less vigorous growth and varying size 

of individuals, are very sensitive indications of changed conditions of environment. For 

measuring short lapses of time and close cont01nporaneity they are n1uch n1ore significant than 

is the specific identity of a single species. 

It rnust be constantly ren1embered that ti10 observed slight differences in form by which 

two closely allied species are distinguished by no n1eans signifies that one is necessarily descended 

directly :frmn the other. The differences nui.y have been established at an earlier stage in the 

racial history than is indicated by the individual smnples under cmnparison; also, the differences rnay be norn1al, fluctuating variations indicating only different conditions of enviromnent 

of which the samples are an adjusted expression. In the case of fossils, of which the continuous 

history is extrmnely deficient, knowledge of the amplitude of fluctuation is very s1nall, and it 

is inlpossible to rely on ~ven the closest similarity in fornl of two smnples alone as indicative 

of the smne age, for it has been shown by other evidence that such similarity may occur in 

smnples separated by hundreds and even thousands of feet thickness of strata. 

vVhere a recurrent fauna, such as I have been describing in this report, c~nsisting of 

several n.ssociated species, suddenly intrudes itself, with its characters intact, into the 1nidst of 

a genernl, faunn. with which it shows slight con1n1unity of composition, it furnishes a record 
84 RECURRENT TROPIDOLEPTUS ZONES IN NEW YORK. 

which has positive time value, be~ause the continuity of generation of the recurrent fauna is 

attested by its contrast with the faunas that separate it in a continuous geologic column fron1 

the formation in which its earlier· appearance is recorde~. 

CHANGES IN FAUNAS. 

So long as a particular fauna continues to 1nark the successive strata of a local geologic 

section, it is reasonable to infer that the life environment of the fauna rmnained reasonably 

constant in the area. It is also reasonable to infer that change of the faunal constitution, of 

the fauna marking the strata is indication of a change of environnlent forbidding continuous 

generation of the species of the fauna. The point in time indicated by the change fr01n one 

fauna to another is necessarily definite, being made so by the two contrasted faunas, one of 

which ceases and the other begins to occupy the particular area. Owing to the universality 

of diastrophic n1ove'ments the point of time when one fauna suceeds another differs with locality. 

But in any one place the difference in time becomes apparent when the earlier fauna recurs. 

RECURRENCE OF FAUNAS. 

Inthe Watkins Glen and Catatonk quadrangles there are three recurrences of the Tropidoleptus fauna at places in the general section made. apparent by their relation to the general 

fauna into which they are intruded. The slight difference in tune incident to trnnsgression 

from on~ place to another. bec01nes also expressed by the fossils, showing the d1.rection of the movement by which the change in the faunas was produced. If the fonns 

diagnostic of these re<;mrrent zones had become modified sufficiently to change their 

identity it would be nnpossible to speak with certainty as tQ ·the continuity of the 

race. If they had not recurred in these successive zones, the tin1e signified by each 

zone could not be affirmed. It is the combination of continuity of the I-Iamiltoniari 

fauna and its expression at definite stages in. the· history of the succeeding Portage 

·and Chemung faunas that gives this recurrence its significance. ·The species themselves. are 

shown to be long lived as 1neasured by geologic· formational time; but the event in their history 

expressed by then· recurrence marks a .definite point in geologic time which occurred but once . 

with the san1e relations; its repetition is n1arked by changed relations. The place and time of 

each particular diastrophic movement is fixed by the fossil records, and I fail to see any possible 

means of recording the time identity (contemporaneity) of such movements ,in other parts of the 

world except by the fossil records. ' 
PLATE I. · 

85 

I . 
PLATE I. 

TROPIDOLEPTUS CARINATUS (Conrad). 

A series of specimens from a single bed (Hd. 13 G, 1r) in zone No. 1 (in Enfield shale member of the Portage 

formation), at Harford Mills. U. S. Nat. Mus. Cat. 59603. 

FIGURES 1-27. Molds of the interior of pedicle valves. 

FIGURES 28-38. Molds of the interior of brachial val¥es. 

FIGURES 39, 42-64. Molds of the exterior of brachial valves. 

FIGURES 40, 41. Molds of th~ exterior of two small pedicle ·valves. 

FIGURES 42-44, 46, 55. Molds showing initial convexity followed by outward curvature, making general concavity· 

of the mature shell, as in figures 48, 53, 59, and 60. ·, · . 

FIGURE 47. Mold showing in extreme the wide card.inal part of shell and the rapidly narrowing sides characteristic 

of var. zeta. 

FIGURES 59, 63, 64. Molds·showing decided geniculation outward of the shell of the brachial valve. 

86 · ... 
U. S. GEOLOGICAL SURVEY PROFESSIONA L PAPER 79 PLATE I 

··tf 

1 2 4 5 

7 8 9 

10 11 12 

13 14 15 16 

17 18 

19 

21 . 20 22 

23 24 25 26 '27 

28 29 30 31 32 

33 34 35 

36 38 39 

40 41 

42 43 44 45 

47 

46 

48 

49 50 51 52 

53 

54 

55 56 

57 59 

60 61 62 63 64 

T ROPIDOLEPTU S CA RINATU S (CONRAD). 
PLATE II. 

87 
PLATE II. 

TROPIDOLEPTUS CARINATUS (Conrad). 

FIGURES 1-24. Molds of the exterior of brachial valves of normal flattened forms belonging to the series repre. 

sented on Plate I. All from a s~ngle bed (Hd. 13G1 1r) in the zone No. 1 (in Enfield shale member of the Portage 

formation) at Harford Mills. U. S. Nat. Mus. Cat. No. 59603. 

FIGURES 25-27. Mature specimens of pedicle valves sho'Ying characteristics of var. typicalis. From the Hamilton 

formation from Kashong Creek, N.Y. U.S. Nat. Mus. Cat. No. 59604. 

FIGURE 28. Mold of the exterior of a brachial valve pf var. alpha. From Hamilton formation, Brookfield, Madison 

County, N.Y. U.S. Nat. Mus. No. 59605. . 

FIGURE 29. Mold of the exterior of a large brachial valve showing a decided sulCus, involving three plications 

toward front of the shell. From Hamilton formation of Brookfield, Madison County, N.Y. U. S. Nat. Mus. Cat. No. 

59605. 

FIGURE 30. Mold of exterior; shows also the interior along the hinge line of the brachial valve. From Hamilton 

formation, Smyrna, Chenango County, N.Y. U.S. Nat. Mus. Cat. No. 59606. · 

FIGURE 31. Mold of the exterior of a brachial valve of var. typicalis. From Hamilton formation, Sherburne, Chenango County, N.Y. U.S. Nat. Mus. Cat. No. 59607. · 

88 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 79 PLATE II 

2 4 3 5 

7 8 9 

10 11 12 

13 14 15 16 

17 

18 

19 20 21 22 23 24 

25 

27 

26 

31 

29 

TROPIDOLEPTUS CARINATUS (CONRAD). 
·;.· 

PLATE III. 

89 
PLATE III. 

RHIPIDOMELLA V ANUXEMI HALL AND VARIETIES. 

FIGURE 1. Rhipidomella vanuxemi Hall. Mold of the interior of a pedicle valve, showing the form and muscular 

impressions. This is a fairly normal expression of typical R. vanuxemi (cf. Paleontology: Geol. Survey New York, 

vol. 4, Pl. VI, :fig. 3m). From Hamilton formation, shore of Cayuga Lake, central New York. H. H. Smith, collector. 

Cornell University Museum 9139.2. · 

FIGURE 2. Rhipidomella vanuxemi Hall. Mold of interior of pedicle valve, showing the left side of the shell with 

form of R. vanuxemi, the right side with form of R. penelope, and the center lobes of the muscular scar produced forward 

as in specimen :figurecl. in Paleontology: Geol. Survey New York, vol. 8, pt. 1, Pl. VI, A, fig. 8. From Hamilton 

formation, shore of Cayuga Lake, central New York. H. H. Smith, collector. Cornell University Museum 9139.4. 

FIGURE 3. Rhipidomella vanuxemi Hall. Mold of interior of pedicle valve, compared with typical R. vanuxemi. 

This shell is much more convex on the umbonal region, is narrower, and has its greatest width lower down (as in R. 

leucosia). The muscular scar is also smaller and narrower than· normal. From Hamilton formation, shor·e of Cayuga 

Lake, central New York. H. H. Smith, collector. Cornell University Museum 9139.3. 

FI$)-URE 4. Rhipidomella vanuxemi Hall. Mold of iJ?-terior of pedicle valve. The muscular scar is 'Strongly impressed, not fanlike as in typical R. vanuxemi; the center lobes are strong though not produced forward of the boundary 

of the main scar. From Tropidoleptus zone No. 1, in Enfield shale member of Portag~ formation. (Dr. 3D, 1o, U.S. 

Geol. Survey), lt miles south of Dryden Lake, Tompkins County, N.Y. U. S. Nat. Mus. Cat. No. 59610. 

FIGURE 5. Rhipidomella vanuxemi Hall. Mold of the interior of a pedicle valve of med~um size,, somewhat flattened in t4e rock. Shell structure thin; muscular impressions faintly expressed and relatively small in size; form · 

that of normal R. vanuxemi of corresponding size. From Ithaca shale member of the Portage formation, at the foot of 

Buttermilk Creek, South Ithaca, Tompkins County, N.Y. E. M. Kindle, collector. Cornell University Museum 10457. 

FIGURE 6. Rhipidomella vanuxemi Hall. Mold of the interior of a pedicle valve, with a small and unsymmetrical 

muscular scar; front center of the shell produced more than normal. The lobes of the muscular scar on the right side 

are faintly divided and normal in shape; those on the left abnormal and separated by strong ridges. From zone No. lj 

in Enfield shale member of the Portage formation (Hd. 13G, 1s, U. S. Geol. Survey), Harford Mills section, south of 

Harford,,Cortland County, N.Y. L. Reinecke, collector. U.S. Nat. Mus. Cat. No. 59611. 

FIGURE 7. Rhipidomella cf. penelope Hall. Mold of the interior of a pedicle valve exhibiting the outline of R. 

penelope in its broad flattened shell, and in the finely subdivided lobes of the muscular scar, but showin~ the bound1).ries of the muscular scar faintly i.mpressed. From Tropidoleptus zone No. 1 in Enfield shale member of the Portage 

formation (Ow. 9A, ll, U.S. Geol. Survey), west of North Candor, Tioga County, N.Y. V. H. Barnett, collector. U.S. 

Nat. Mus. Cat. No. 59612. 

FIGURE 8. Rhipidomella vanuxemi Hall. Mold of the interior of a pedicle valve from the same fauna as figure 6; 

showing an abnormal development of ridges separating the lobes of the muscular scar on both sides. From Tropidoleptus zone No. lin Enfield shale member of the Portage formation, same locality and collector as specimen of :figure 6. 

U. S. Nat. Mus. Cat. Nu. 59611. . 

.FIGURE 9. Rhipidomella vanuxemi Hall. Mold of interior of a pedicle valve showing faint muscillar impressions 

ana strong median ridge separating the two lobes of the scar and produced forward beyond their front margin. The 

unsymmetrical form is probably due to movement in the rock matrix after fossilization. From Tropidoleptus zone 

No. 1 in Enfield shale member of the Portage formation (Ow. 9A, ll, U.S. Geol. Survey); same stratum as figure 7. 

U. S. Nat. Mus. Cat. No. 59612. · 

FIGURE 10. RlJ,ipidomella vanuxemi Hall. Mold of the interior of a pedicle valve, the cardinal angles of which 

are absent, showing the flattened surface of the shell, the fairly large fan-shaped :nuscular scars, and the strong median 

ridge. From Tropidoleptus,zone No. 1 in Enfield shale member of the Portage formation (Rd. 13G,· lr), Harford Mills 

section. L. Reinecke, collector. U. S. Nat. Mus. Cat. No. 59611. 

FIGURE 11. Rhipidomella vanuxemi Hall. Mold of the interior of a pedicle valve of abnormally elongate form· 

The elongation affects the shape of the muscular scar as well as the outline of the shell and results in a forward development of the two inner lobes of the muscular scar of both sides. The ridges bounding the muscular scar and teeth plates 

are both strongly developed. From Tropidoleptus zone No. 1 in Enfield shale member of the Portage formation (Ow. 

9A, lm, U.S. Geol. Survey), west of North Candor, Tioga County, N.Y. V. H. Barnett, collector. U. S. Nat. Mus. 

Cat. No. 59613. 

FIGURE 12. Rhipidomella vanuxemi Hall. Mold of the interior of a brachial valve, showing the cardinal pl,'Ocess, 

the rather strongly developed crural plates, and the narrow but strong ridge between the muscular scars. The shell 

90 
U.S. GEOLOGICAL SUR VEY PROFESSIONAL PAPER 79 PLATE Ill 

1 2 3 

4 5 

6 

8 

7 9 

10 11 12 

13 . 14 15 

16 17 18 

RHIPIDOMELLA VANUXEMI HALL AND VARIETIES. 
PLATE III. 91 

of the specimen is so thin as to show distinctly the radial lineation on the inner surface, and the muscular scar is so 

faintly expressed as to fail of observation. From Tropidoleptus zone No. 1 in Enfield shale member of the Portage 

formation (Hd. 13G, 1r), Harford Mills section. L. Reinecke, collector. U. S. Nat. Mus. Cat. No. 59611. 

FIGURE 13. Rhipidomella vanuxemi Hall. Mold of the interior of a pedicle valve, particularly broad, as in R. 

penelope. The muscular scar is large and fan-shaped; the ridges separating into lobes are strong, and the outside 

margins of the impressions are strongly expressed·. The beak portion is broken off, giving the appearance of a more 

quadrate form than it actually had. The shell was slightly concave: From Tropidoleptus zone No. 3, ·in Cayuta 

shale member of the' Chemung formation (Wv. llH, la, U.S. Geol. Survey), North Chemung, Chemung County,.N. Y., 

at altitude of 1,440 feet. E. M. Kindle, collector. U. S. Nat. Mus. Cat. No. 59614. 

FIGURE 14. ,Rhipidomella vanuxemi Hall. Mold of the interior of the brachial valve of the specimen shown in 

figure 13, showing the convexity of the _valve and near the front the original shell. This specimen well expresses 

the four parts of the adductor scar figured by Hall (Paleontology: Geol. Survey New York,·vol. 8, pt. 1, Pl. VI, A, fig. 7). 

From Tropidoleptus zone .No.3 in Cayuta shale member of the Chemung formation; same location as figure 13. U. S. 

Nat. Mus. Cat. No. 59614. 

FIGURE 15. Rhipidomella vanuxemi Hall. Mold of the interior of a pedicle valve, showing the convex form of the 

· cardinal side of the shell, flattened anteriorly, as in normal R. vanuxemi. The muscular scar is fan-shaped; the 'two 

middle lobes are strongly. developed, and the hinge teeth strong. From Tropidoleptus zone No. 3 in Cayuta shale 

member of the Chemung formation (El. 1E, 1a, U. S. Geol. Survey), one-fourth mile southwest of Breesport, Chemung 

County, N.Y., at an altitude of 1,420 feet. U.S. Nat. Mus. Cat. No. 59615. · 

FIGURE 16. Rhipidorriella vanuxemi Hall. Mold of the interior of a brachial valve, showing the cardinal process, 

crural plates, and the rather broad median ridge separating the faint impressions of the muscular scars. From Tropidoleptus zone No. 3 in Cayuta shale member of the Chemung formation (Wv. 7B, lj2), southwest of Swartwood station, near thesummitof Austin Hill, in Chemung County, N.Y. C. L. Breger, collector. U.S. Nat. Mus. Cat. No. 59616. 

FwunE 17. Rhipidomella vanuxemi Hall. Mold of the interior of a pedicle valve of medium size, showing muscular 

:scar with not strongly developed outside boundary ridges but with strong ridges dividing it.s lobes and strong median 

ridge. The surface form is convex in the umbonal part and flattened toward the front. From Tropidoleptus zone No.3 

in Cayuta shale member of the Chemung formation (Wv. 7B, 1j2), southwest of Swartwood Station, ·near summit of 

Aus~in Hill in Chepmng County, N.Y. C. L. Breger, collector. U.S. Nat. Mus. Cat. No. 59616. 

FIGunE 18. Rhipidomella vanuxemi Hall. Mold of the interior of a pedicle valve showing the wide form of R. 

le?.teos1:a. The form of the muscular scar is similar to that shown in figure 2 from the Hamilton; the two slender grooves 

ne~r the median line extencUorward nearly to the front margin of the shell, as in figure '7. From Tropidoleptus zone 

No. 3 in Cayuta shale member of the Chemung formation (Wv. lUI, 1a), North Chemung, Chemung County, N. Y., 

at altitude of 1,440 feet. E. M. Kindle, collector. U~ S. Nat. Mus. Cat. No. 59614. 

~· 

'""' PLATE IV. 

93 
PLATE IV. 

8PIRIFER MARCY! HALL AND VARIETIES. 

FIGuRE 1. Spirifer marcyi typicalis. Interior mold of a pedicle valve, showing the form, the surface pli~'ations, the 

muscularscars and dental plates. From Tropidoleptus zone No. 3 in Cayuta shale metnber of Chemung formation 

(Wv. 7B, 1jjj), on Austin Hill south of Swartwood. C. L. Breger, collector. U.S. Nat. Mus. Cat. No. 59617. 

FIGURE 2. Spirifer marcyi typicalis. Interior mold of hinge portion of the pedicle valve, showing the moderately 

elevated area, the strong dental plates, the transverse plate in the upper part of the cavity of the beak, and the faint · 

indication of the rudimentary syringeal plates on the inner side of the dental plates. Same specimen as figure 1. 

From Tropidoleptus zone No. 3 in Cayuta shale member of Chemung formation (\Vv. 7B, )jjj), on Austin Hill, south 

of Swartwood, N.Y. U.S. Nat. Mus. Cat. No. 59617. 

FIGURE 3. Spirifer marcyi beta. Interior mold of a pedicle valve, showing the form, the surface plications, the 

muscular scar, the dental plates, and a median septum separating the anterior portion of the diductor muscular scars. 

From Tropidoleptus zone No. 2 in Cayuta shale member of Chemung formation, quarry on south ·side Cemetery Hill, 

Owego, N. Y. (1130A.) H. S. Williams, collector. U. S. Nat. Mus. Cat. No. 59618. 

FIGunE 4. Spirifer marcyi beta. Interior mold of hinge portion of pedicle valve, showing the dental plates and the 

moderately high area. The dental plates are united near the apex of the umbonal cavity by a transverse plate. Specimen same as figure 3. U. S. Nat. Mus. Cat. No. 59618. 

FIGURE 5. Spinfer marcyi beta. Inte1'ior mold of a crushed pedicle valve, showing the effect of crushing in distorting the form of the valve; compare with figure 3. From Tropidoleptus zone No. 2 in Cayuta shale membe~ of 

Chemung formation, quarry on south side Cemetery Hill, Owego, N.Y. (1130A.) H. S. Will:huns, collector. U. S. 

Nat. Mus. Cat. No. 59618. 

FIGuRE 6. Spirijer marcyi beta. Interior mold of a pedicle valve, showing the area and slender short dental plates, 

with very short transverse plates. From Tropidoleptus zone No. 2 in Cayuta shale member of Chemung formation, 

cemetery quarry, Owego, N.Y. (1130A.) H. S. Williams, collector. U. S. Nat. Mus. Cat. No. 59618. 

FIGuRE 7. Spirijer marcyi gamma. Interior mold of a pe~licle valve, showing the form, the high na~:row beak, the 

short dental plates, the slight median septum, and the faint muscular scars. From Tropidoleptus zone No. 2 in Cayuta 

shale n1ember of Chemung formation, cemetrry quarry, Owego, N.Y. (1130A.) H. S. \Villiams, collector. U. S. 

Nat. Mus. Cat. No. 59619. 

FIGUilE 8. Spir~fer marcyi gamma. Interior mold of pedicle valve; areal vie\v, showing the high erect area, subparallel dental plates, short transverse plates, rudimentary syringeal plates near apex of the umbonal cavity, and 

vascular pitting of the interior of the hinge area. From Tropidoleptus zone No. 2 in Cayuta shale member of Chemung 

formation, cemetery quarry, Owego, N.Y. (ll30A.) H. S. \Villiams, collector. U. S. Nat. Mus. Cat. No. 59619. 

FIGunE 9. 8pirijer marcyi della. Interior mold of pedicle valve, showing the form of the valve, the rudin1entary 

dichotdmizing of the plications near the middle of the valve, and the auxiliary plications,on the slopes of the median 

sulcus. From Tropidoleptus zone No. 2 in Cayuta sl;ale member of Chemung formation (El. 6L, 1q), quarry, 1 mile 

southwest of Southport, Chemung County, N.Y., at elevation of about 1,000 feet. E. M. Kindle, collector. U. S. 

Nat. Mus. Cat. No. 59620. 

Fwmm 10. Spirifer marcyi sigma. Interior mold of the areal portion of a pedicle valve (X 2). The specimen, 

which is imperfect and somewhat crushed, belongs in form to var. beta. The specimen shows the dental plates united 

by a strong transverse plate, from which the two syringeal plates parallel to the dental plates are directed forward 

· fromthe transverse plate, being developed downward from the apical portion of the umbonal cavity. From Tropidoieptus zone No. lin Enfield shale member of Portage formation (Dr. 8I, 1c), White Church section, Caroline, Tompkins 

County, N.Y. C. L. Breger, ~ollector. U. S. Nat. Mus. Cat. No. 59621. 

94 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 79 PLATE IV 

2 

1 

4 

3 

5 6 

7 

10 

SPIRJFER MARCY! HALL AND VARIETIES. 
PLATE V. 

95 
PLATE V. 

SPIRIFER AND SYRINGOTHYRIS. 

FIGURE l. Spirifer granulosus sigma. Internal mold of a pedicle valve, showing form, plications, faint muscular 

scar, and thin dental plates. From upper part of Hamilton formation, Smyrna, Chenango County, N.Y. (1066A3.) 

C. S. Prosser, collector. U. S. Nat. Mus. Cat. No. 59625. 

FIGURE 2. Spirifer granulosus sigma. Opposite side of specimen shown in figure l. From Smyrna, Chenango 

Coupty, N.Y. (1066A3 .) U.S. Nat. Mus. Cat. No. 59625. 

FIGURE 3. Spirifer marcyi gamma. Brachial valve of spec~en shown in Plate IV, figures 7 and 8. Internal mold 

of brachial valve, showing form, plications, and median fold. From Tropidoleptus zone No.2 in Cayuta shale member 

of Chemung formation, cemetery quarry, Owego, N: Y. (1130A.) H. S. Williams, collector. U.S. Nat. Mus. Cat. 

No. 59619. · · 

FIGURE 4. Spirifer granulosus sigma. Same specimen as in figures 1 and 2. Internal mold of cardinal side of 

specimen, showing cardinal view of two'valves united (X 2). At the apex of the umbonal cavity is seen the twisted 

plate connecting the two dental plates and forming a rudimentary syrinx, which is m~re fully developed in typical 

specimens of Syringothyris. From upper part of Hamilton formation, Smyrna, Chenango County, N.Y. (1066N1.) 

C. S. Prosser, collector. U.S. Nat. Mus. Oat. No. 59625. 

FIGURE 5 .. Spirifer marcyi beta. Mold of exterior surface of a brachial ·valve, showing plications and fold and the 

surface pustules (X 2). From Tropidoleptus zone No.2 in Cayuta shale member of Chemung formation, cemetery 

quarry, Owego, Tioga County, N.Y. (ll30A.) H. S. vVilliams, collector. U.S. Nat. Mus. Cat. No. 59618. 

FIGURE 6. Syringothyris typa A. Winchell. Mold of interior surface of a pedicle valve and exterior surface of the 

hinge area. Showing the muscular sc'ar, dental plates, and interior face of the cardinal area and narrow delthyrium. 

From early Mississippian, Carboniferous system, Smethport, Pa. (147lB6 .) E. M. Kindle, collector. U. S. Nat. 

Mus. Oat. No. 59626. 

FIGURE 7. Syringothyris typa A. Winchell. Apical view of same specimen as figure· 6, showing a mold of the 

dental plates, connected at the apex of the umbonal cavity by the base of the twisted syringeal plates. This figure 

also shows the ridge connecting the syringeal plates with the median platform separating the posterior lobes of the 

adductor muscular scar. From early Mississippian, Carboniferous system, Smethport, Pa. (1471B6 .) E. M. Kindle, 

collector. U. S. Nat. Mus. Oat. No. 59626. 

FIGURE 8. Spirifer marcyi zeta. Mold: of the exterior surface·of a brachial valve (about X 2), showing the narrow 

attenuated form, 'the addition to number of plications on the mucronated extension of the shell, and the pustules on 

the surface. From Tropidoleptus zone No.2 in Cayuta shale member of Chemung formation (Wv. 7B, 1p), Swartwood, 

Chemung County, N.Y. C. L. Breger, collector. U.S. Nat. Mus. Oat. No. 59622. 

FIGURE 9. Spirifer marcyi epsilon. Mold of exterior surface (about X 3), showing the exterior surface characters 

of a brachial valve, mucronate form. Of the numerous plic~tions one near the left end of the figure is distinctly bifurcated. The pustules are also elongate, and show a tendency to form continuous longitudinal lines on the median fold. 

From Cayuta shale member of Chemung formation (El. 2M, p4), Ashland Hill, south of Elmira in Ashland Township, 

Chemung County, N.Y., at 950 feet elevation. E. M. Kindle, collector. U.S. Nat. Mus. Oat. No. 59623. 

FIG.URE' 10. Spirifer marcyi beta. Mold of interior of the brachial valve of the specimen figured on Plate IV, figures 

5 and 6. Showing the characteristic expression of var. beta (compare with figs. 3, 8, and 11). From Tropidoleptus 

2;one No.2 in Cayuta shale membe.r of Chemung formation, quarry on south side of cemetery hill, Owego, Tioga County, 

N. Y. (1130A.) H. S. Williams, collector. U. S. Nat. Mus. Oat. No. 59618. 1 

FIGURE 11. Spirijer marcyi typicalis: Mold of the interior of a large specimen, showing the interior of a brachial 

valve; the muscular scars and vascular pittings are sharply expressed. From Tropidoleptus zone No. 3 in Cayuta 

shale member of the Chemung formation, near the top of the ravine west of Spencer Lake, northwest of Spencer, Tioga 

County, N. Y:- U.S. Nat. Mus. Oat. No. 59624. 

FIGURE 12. Spirifer mar<:~Ji epsilon. Interior mold of specimen shown in figure 9 (X 2). Showing the form and 

plication. One of the plications on the right end of the specimen is bifurcated. From Cayuta shale member of Chemu.ng formation (El. 2M, p 4 ), Ashland Hill, south of Elmira in Ashland Township, at elevation of 950 feet. E.M. Kindle, 

collector. U. S. Nat. Mus. Oat. No. 59623. 

FIGURE .13. Spirifer mar<:~Ji delta. Mold of exterior surface of pedicle valve of specimen represented in Plate I, 

figure 9. Showing the rudimentary duplkation of the plications, the surface pustules, and the supplementary plicationa on the s~des of the sulcus. From Tropidoleptus zone No. 2 in Cayuta shale member of Chemung formation 

(El. 6L, 1 q), quarry 1 mile southwest of Southport, Chemung County, N.Y., at elevation of 1,000 feet. E. l\f. Kindle, 

collector. U. S. Nat. Mus. Oat. No. 59620. 

96 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 79 PLAT E V 

1 2 

4 

5 

7 

8 

6 

11 

12 

SPIRIFER AND SYRINGOTHYRIS. 
·PLATE VI. 

97 
PLATE ·vi. 

0YPRICARDELLA BELLlSTRIATA (Conrad). 

FIGURES 1-6, 8, 14. Specimens from the Hamilton formation at Sheldrake ravine, Cayuga Lake. U. S. Nat. 

'Mus. Cat. No. 59627. 

FIGURES 7, 9-12. Specimens from the Ithaca shale member of the Portage formation, Ithaca, N.Y. U.S. Nat. 

Mus. Cat. No. 59628. . . . - FIGURES 13, 15-18, 21. Specimens from the recurrent Tropidoleptus zone No.2 in the Cayuta shale member of the 

Chemung formation, Owego, Tioga C,ounty, N.Y. U.S. Nat. Mus. Cat. No. 59629. 

FIGURES 19, 20. Specimens fro_m Tropidoleptus zone No.3 at the top of the Cayuta shale member of the Chemung 

formation, Austin Hill, southwest of Swartwood, Chemung County, N.Y. U.S. Nat. Mus. Cat: No. 59630. 

98 
U.S. GEOLOGICAL SURV EY PROFESSIONAL PAPER 79 PLATE VI 

3 4 

2 

1 

7 

6 8 

5 

11 

10 

9 12 13 

15 

16 

17 

14 

·20 

18 

19 

21 

CYPRICARDELLA BELLISTRIATA (CONRAD ). 
INDEX. 

Figures in italic refer to illustrations. 

A. Page. 

Actinopteria .............. ~ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 

boydi........................................................ 14 

Ambocrolia .................................................... 32,34,35 

gregaria. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 

umbonata ........................................... 11-14,16-22,74 

gregaria. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 

Apalachin, faunule at, designation of. ............................ 10,31 

faunule at, elevation of .................................... 10,22,31 

fauna of.................................................. 22 

zone of.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10, 31 

Apalachin quadrangle, faunules from ....................... 8,66,68, 73 

subdivision of................................................. 8 

Area investigated, extent of ................................. ,.... 8 

Athyris polita ................................................ , ... 13,32 

Atryp!L ..................................... · .................... 34,35 

retieularis ................. ~· ........................ 11-14,16-18,32 

spinosa ................................................ 13-15,17,32 

Aulopora... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 

Austin Ilill, faunule at, designation of ............................ 10,32 

faunu)e at, elevation of ................................. 10,13-14,32 

fauna of. ........................................... 14,91,94,98 

zone of ........................... ·'· ............... : ...... 10,32 

A viculopecten. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 

duplicatus ............................... :. . . . . . . . . . . . . . . . . . . 13 

fasciculatus.................................................. 18 

princeps .................................................. 12, 21,74 

suborbicularis................................................ '16 

sp ............................................................ 17,18 

Bald Ilill, faunule at, data on .................................... 10,17 

faunule at~ designation of.. . . . .. .. . .. .. . .. . . . .. . . .. .. . .. . . . . . 10 

faunaof ................................. :................ 17 

section at................................................ 27 

figure showing. . . .. .. .. . . . . . . .. . .. . .. .. .. . .. . .. .. .. . . 25 

Bald Mountain, faunule at, designation of. ....................... 10,31 

faunule at, elevation of .................................... 10,17,31 

fauna of.................................................. 17 

zone of. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10, 31 

Bellerophon..................... ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 

brevilineatus ................................................. 12,74 

incisus....................................................... 19 

leda.................................................... .. . . . . 12 

macra.... .. . . . . . . .. .. .. .. .. . .. .. .. .. .. . . . . . . . .. .. .. . . . ... .. .. 23 

pclops ...................................................... : 15 

trilira tus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . 13 

sp ............................................. , ........ 16,18, 20,23 

Berkshire, faunule at, designation of ............................. 10,31 

faunule at, elevation of .................................... 10,22,31 

fauna of.................................................. 22 

zone of. .................................................. 10,31 

section at ............................. · .... .'. . . . . . . . . . . . . . . . . . 30 

figure showing... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 

Blodgett Mills, faunule at, designation of. ........................ 10,31_ 

faunule at, elevation of .................................... 10,20,31 

fauna of.................................................. 8, 20 

zone of ................................................... 10,31 

section at ......... .' ................................ :. . . . . . . . . 29 

figure showing. . . . .. . . . .. . . . . .. . . .. . . . . . . . . . . .. .. . .. . .. . . 29 

Breesport, faunule at, designation of. ............................ 10,32 

faunule at, elevation of. ..... .' ... _. ......................... 10,11, 32 

fauna of .................................................. 11,91 

zone of ................................. , .................. 10.32 

section at .................................................... 27-29 

figure showing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 

Page. 

Brookton, section at .............................................. 26-27 

section at, figure showing . .. . .. . . . . .. . . .. . . . . .. . . . . . . . . . .. . . . 25 

Buttermilk Creek raYine (B), fauna in ......................... 31,32,90 

c. Camarotoochia ........................................ 34, 35, 36,67-68,73 

congregata ....................................... 16,19, 20, 32,67-68 

contracta ................................ 11,13-15,18,20,21,32,67-68 

eximia ........................................... 16-18,20-22,67-68 

eximia-stephani. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67-68 

sappho ............................... 11-13, 15, 16, 19, 21, 22, 32,67-68 

stephani.. ................................................. 12, 14,67 

sp ...................................................... 17,.18,20,22 

Camarotrochia genus, occurrence of...... . . . . . . . 11-22,32,34-36,67-68, 73 

recurrence of................................................. 68 

specific discrimination of ..................................... 67-68 

Cascadilla Creek (C), fauna at ................................. 31,32,63 

Catatonk, section at.............................................. 27 

section at, figure showing..................................... 27 

Catatonk quadrangle, location and parts of. . . . . . . . . . . . . . . . . . . . . . . 8 

section in, figure showing...................................... 23 

See also Dryden; Ilarford; Owego; Apalachin quadrangles. 

Cayuta, faunule at, designation of. ............................... 10,31 

fau.nule at, elevation of ................................ : ... ·10, 12,31 

fauna of. ........... ·-.................................... 12 

zone of. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10,31 

Cayuta shale member, recurrent zones in......................... 7 

section of, figure showing ............ :......................... 23 

See also Tropidoleptus zones. 

Center Lisle, faunule at, designation of. .......................... 10,31 

faunule at, elevation of. ................................... 10,21,31 

fauna of.................................................. 21 

zone of ................................................... 10,31 

Ceratopora....................................................... 32 

chemungensis................................................ 13 

Chemung formation, recurrent zones in .......................... . 

recurrent zones in, figures showing ........................... 23-30 

See also Cayuta shale member; Ithaca shale member. 

Chenango Valley, section in, figure showing...................... 23 

Chonetes ......................................................... 34,35 

defl.cctus. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20, 32 

scitulus ............................................. 11,13-18,20,21 

sctigera..... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 

setigera-scitu I us.. . . . . . . . .. . . .. .. . . . . . .. . . . .. .. . . . . . .. .. . .. . . . 18 

sp.. .. .. .. . .. .. .. .. . .. .. .. .. .. .. .. . .. . . . .. .. .. . . . . . . . II, 12, 16, 18, 23 

Cladochonus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 

sp ...................................................... 13,17, 18,19 

Coleolus... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 

aciculum ..................................................... 15, 18 

Conrad, T. A., cited.............................................. 36 

Conularia. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 

sp............................ ... ... .. .... .. ... . . . ... . . .. . . . ... 13 

Cortlan~ qu~drangle, faunules from ......................... 8, 66, 68, 73 

sectwns In.................................................... 29 

figure showing....... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 

subdivision of................................................ 8 

Crania Ieoni. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13, 32 

Craniella. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... . . . . . . . . . . . . . . . . 32 

hamiltoniro ................................................ 14,15,21 

Crenipecten ........................................ : .·.. ... .. .. . .. . 32 

crenulatus.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 

sp ........................................................... , 20 

99 
100 INDEX. 

Page. 

Crinoi4 stems ........................................ 13, 15, 18,20-23,30 

Cryptonella ......... ; .......... · ............................ .". . . . . 32 

sp.... ... .. .. . ... ..... ......... ........ .. ...... .. ........ ..... 12 

Cypricardella ........................................... 32, 34, 35, 36,73 

bellistriata ..... ~ ...................... 8,13-17,19-22,68-70,73-74,98 

alpha ............................. :....................... 69 

beta...................................................... 69 

minor ......................................... ·····'····· 69 

typicalis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 

complanata ................... ~.............................. 70 

elongata. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 

gregaria. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 

tenuistriata..................... .•. . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 

Cypricardella genus, European occurrence of ..................... 7o-71 

occurrence of ....................... 8,13-17,19-22,32,34-36,68-71,73 

range of ...................................................... 68-69 

recurrence of ............................................. _. . . . 68-70 

specific characters of. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69-70 

Cypricardinia. . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . .. .. . . . . . . . . . . . . . 32 

sp... .. . .. ... .. .. ... ... .. .. ...... .......................... .. . 18 

Cyrtina.. .... .. ... ........ .............. ............ .. .. .......... 32 

hamiltonensis ............................. · ... 13, 15, 16, 18, 20, 21,74 

D. 

Dalmanella. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . .. .. . . . . . 32, 34,35 

carinata .............................. ~ . . . . . . . . . . . . . . . . . . . . . . . 13,28 

elmira .................................... : . . . . . . . . . . . . . . . . . . . 28 

tioga ....................... \- .......................... 11-15,17,28 

Dalmanella danbyi zone, position of. ....................... 24,27-28,29 

position of, figures showing ............................. 23, 25, 26,28 

Dalmanella tioga .zone, position of, figure showing. . . . . . . . . . . . . . . . 28 

Deans Tannery, section at....................................... 27 

section at, figure showing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 

Delthyris ......................................... 32, 34,35-36, 73,76-77 

consobrinus. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20, 66-67, 76 

mesicostalis ................................. 8, 11-23,65-67,73-74,76 

Delthyris genus, occurrence of ............. 8, 11-23,32, 34,35-36, 65-67, 73 

recurrence of. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66-67, 77 

specific characters of . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65-66 

Deposition, time relations of. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83-84 

Deputron Creek, faunule at, designation of ....................... 10,31 

faunule at, elevation of. ................................... 10, 18,31 

fauna of. . , ............................................... ' 18 

zone of.. . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10, 31 

Devonian system, recurrent zone in.............................. 7 

Diastrophism, evidence of.. .................................... 7,81-82 

explanation of ............ , ................................... 8o-81 

time relations of.. ............................................ 81-82 

Douvillina cayuta ...................................... : ...... 13,28,32 

Dryden Lake, faunule at, designation of .......................... 10,31 

faunule at, elevation of ................................. 10,16,17,31 

fauna of .................................................. 17,90 

zone or ... : ............ , ................. ' ....... : . . . . . . . . . 1 o, 31 

Dryden quadrangle, faunules from.......................... 8, 66, 68, 73 

section in .................................................... 26-27 

figures showing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24, 25 

subdivision of................................................ 8 

E. 

East Branch, section at.......................................... 29 

section at, figure showing. . . . . . . . . . . . .. . . . . . . . . ... . . . . . . . . . . . . 29 

East Danby, faunule at, designation of. ...... : . .................. 10, 31 

faunule at, elevation of. ................................... 10,17,31 

fauna of.................................................. 17 

zone of ........................... '. ....................... 10, 31 

East Elmira, faunule at, designation of ........................... 10,32 

faunule at, elevation of ................................ 1 ••••• 10, 15,32 

fatma of.................................................. 15 

zone of. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10, 32 

East Virgil, section at............................................ 29 

section at, figure showing..................................... 29 

Edmondia. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32· 

phillipi. ................................. :. . . . . . . . . . . . . . . . . . . . 13, 22 

sp ............................................................ 13,23 

Elmira, faunule at, designation of. ............................... 10,32 

faunule at,'elevation of ..... : ..... : ........................ 10, 11,32 

fauna of. ..... · ............. : ...... ··.·· .................... 11,96 

zone of ................................................... 10,32 

section in .......... ; .... : . . :. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-28 

figure showing. ~ ......................... : ..... :. . . . . . . . . 28 

Page. 

Elmira ~ua~rangle, faunules fro!n ........................... 8, 66, 68,73 

sections rn.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-29 

sub~~-~~~h:r'~-~-~--~ ~ :~ :::::::::::::::::::::: :·: :: ~::::::::: :: ~ • 

Enfield shale member, recurrent zone in ............... : ........ . 

section of, figure showing..................................... 23 

See also Tropidoleptus zone No. 1. 

Euomphalus ............ -......................................... 32 

hecale ........................................................ 13, 15 

sp ...................................................... 11, 14, 15, 16 

Euthydesma .......................... : .. .................. ·...... 32 

sub textilis..... . . . . . . .. . . . . . .. . . . .. . . . . . . . . . .. . . . ... . . . . . . . . . . 19 

F. 

Fall Creek, section at ................ : .• ; ......... :............... 24 

section at, figure showing ......................... -............ 26 

Fauna, classification of. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 

grouping of, by areas......................................... 73 

by species and genera .............. , . ·.. . . . . . . . . . . . . . . . . . . 32-33 

identification of ...... · ......................... :. . . . . . . . . . . . . . 76-79 

recurrence of, evidence of.. ............................ : ... 75-79,84 

oscillation in ...... : ...................................... 79-80 

significance of.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . 8o-84 

See also Recurrent zones; Diastrophism. 

time relations of.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83-84 

Faunules, altitudes of, determillation of.......................... 9 

diagnostic genera of .......................................... 73-74 

elimination of.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 

fauna of. .... -........................................... 32-33,73-75 

geographic distribution of.................................... 8-10 

figure showing.-.......................................... 9 

grouping of, by areas.......................................... 73 

by zones .............................................. 31-32, 63 

identification of .............................. :. . . . . . . . . . . . . . . 8-9 

list of......................................................... 10 

species in ........... ·'· . . . . . . . . . . . . . . .. . .. . . .. . .. . . . . . . . . . 10-63 

stratigraphic positions of ..... : . ............................ 8, 23-24 

figures showing ........................................ 24-30,33 

See also particular faunal localities. 

Fenestella ................... · ................... : . . . .. . .. . .. . .. . .. 32 

sp .............. :. .................. ... ... .................... 13 

Fitches Bridge, faunule at, designation of ..................... 10, 31, 32 

-faunule at, elevation of. ............. : .................. 10, 11, 31,32 

fauna of. .................................. ;.............. 11 

Fluctua:~:~ ~~~~~-~f~: .·: ~ ~ ~ ~:: ~ ~ ~ ~: ~ ~ ~ ~: ~ ~ ~: .· ~ .· ~:: .·:: ~ ~ ~ .· ~ ~: .·:. ~~· ~~~~ See also Tropidoleptus; Rhipidomella; Spirifer marcyi. 

n. Genera, grouping by ............................................. 32-33 

Gens, definition of................................................ 53 

racial continuity of.. .................. :-- ............... : .... 77-79 

Geography, ancient, bearing of investigation on.................. 7 

conditions of .......................................... .'...... 72 

change in. . . . . . . . . . . . . . . . . . .. . . . . . . . . . .. . . . . . . . . . . . . .. . . . 79-80 

Geologic sections, figures showing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-30,33 

list of. ......................... , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25-26 

location of. ... ." .............................................. 26-30 

Glenwood, section at............................................. 26 

section at, figure showing. . . . . .. .. .. . .. . .. .. . .. . . . . .. .. . . .. .. 24 

Glory Hill, faunule at, designation of ............................. 10,32 

faunule at, elevation of. ....................... ~ ........... 10, 16,32 

fauna of. .......... ,...................................... 16 

zone of ................................................... 10,32 

section at, figure showing. . .. .. . .. .. . . .. . .. . . . . .. .. . .. . . . . . . . 27 

figure showing ............................... ·. . . . . . . . . . . . 26. 

G lossites .... ~ . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 

Iingualis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 

G lyptodesma ............................. , . . . . . . . . . . . . . . . . . . . . . . 32 

erectum ................... : .................................. 21,74 

sp ................................................. ··: ... ... . 15 

Goniatites ............ ·........................................... 32 

disoideus..................................................... 12 

Goniophora...................................................... 32 

rugosa....................................................... . 20 

Gosselet, method of. .......................................... 44,56-58 

a rammysia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 

elliptica ........... ·........................................... 20 

subarcuata .... ~ .............................................. 13,21 · 

SP:························································ 17,18,20 
INDEX. 101 

H. Pa~:e. Pa.ge.' 

Hall, James, cited ....................................... 3i,38-41,50-53 Lockwood, cast, faunule at, designation of ........ __ .............. 10,32 

Hamilton formation, fauna from .... _ ........ _ ....... 36-i2,88,90,'96,98 faunule at, elevation of. .. ______ .... _ ..... _: ............... 10,15, 32 

Hamilton shale, recurrence of, figure showing __ ... ______ ..... ___ . 23 fauna of ___ . -.- ___ . _ .. __________ .- _____ . _____ . _ .. _. . . . . . . . . . 15 

See also Recurrent zones. zone of .......... ____ .. _______ . ____ . _______ .. ___ .... _ ..... 10,32 

Harford, section at .. ____ ._ ...... _. __ ....... ___ ._ ...... ____ ... _... 29 Lockwood, west, faunule at, designation of. ___ ... ___ .... __ ... ___ . 10. ~,. , 

section at, figure showing. _ ........ __ .. _ .... __ .. __ ...... ___ .. 30 faunule at, elevation of. _____ .. ____ .... ____ .. ____ .... ___ .. _ 10,15, ;, 

Hurford Mills, faunule at, designation of. ___ ..... ____ ._. __________ 10,31 fauna of ____________________ .. _____ .. ____ ... ___ . _ . ___ ... _ . .L.., 

faunule at, elevation of. ____ ............. _ ..... _ .. ______ .. _ 10,21,31 zone of . _ . _ ..... ___ ... ______ . _______ .... _ .... ___ . _ . _ . _ . _ . 10,32 

fmma of. ... ___ ...... __ ........ _._ ...... ___ 21,38-41,86,88,90-91 Loxonema ...... __ ....... ___ ... .". ____ .. _____ . _ . _ . _ . _____ .. _ .... _ _ 32 

zone of._._ ................ _ ......... __ ... _ .... ____ ._ ... __ 10,31 styliola ... __ . _______________ . _______ . _______ . ______ . _____ .... 15 

section at.·······-·····················-·-····-·----·····---- 30 terebra .. __ .... ____________________ . _____ .... ___ . __ . : . ___ . .'. . 13 

figure showing .. ___ ........ _ ......... _ . _ . ___ .. ______ .. _ _ _ 33 sp .............................. _ ...... ___ ....... _ 13,14-H\,19, 20,23 

Harford quadrangle, faunules from .......... ___ .... ___ : ..... 8,66, 68, i3 Lyriopecten __ . ___ . ___ . _______________________ . _. _____ .. ___ .. ___ . 32 

sections in ... _ . ____ .. _ ... ____ ........ _ . _ ..... ____ ..... _ . _ _ _ _ _ 29-30 suborbicularis .. ______ . ____ .. ______ . _. _____ ... ____ .. _ .... _. _.. 14 

figures showing ........... _ ........ ___ .... _____ ....... 29,30,33 sp ................... ___ ....... ____ .. _____ ... __ .... __ .. __ ... _ 1i 

iiiubdivision of................................................ 8 .M:. 

Hawley Hill, section at._ ..................... _ .... ____ .......... 2i-28 

section at, figure showing ..................... : ...... ___ ..... 28 

l\facrocheilina .... _ . _ ... ___ .· .. ___ ... ____ .... __ .... __ .... __ . _ . _ . . . . 32 

macrostoma .. __ ... __ .... __ .... ___ .... _____ .. __ .... __ 12, 15,191 23, i4 

l. sp •................... __ .... _____ .. _____ ... ___ ... __ . _. ___ .. __ 14,15 

Ithaca, faunule at, designation of.. ............... __ .. _.-.. ____ .... 10,31 

faunule at, elevation of ....... _ .............. ____ .... _____ . 10,12,31 

fnuml or ..... --....................... -.... -- -- .. ----. --. - 12 

zone of ... _ ................................... _ . _ .... ____ . 10, 31 

It:hnca quadrangle, faunules from .............. _ ....... _ ..... 8, 66,68, i3 

sections in ...... _____ ........ ____ ..... ____ .... ___ ..... ___ .... _ 26, 2i 

figures showing ..... ____ ....... _: ........ _ .... __ .... ______ 24,25 

subdivision of._ ....... __ ...... ___ ......... _ .... ___ ~_. _______ . 8 

Ithaca shale member, recurrent zone in ... ___ ... _________ . __ .. ___ _ 

section or, figure showing ..... _____ .... _____ ... ______ . ____ .. __ 23 

See also Tropidoleptus zone of Ithaca shale member. 

Macrodon .... ___ ... ____ .. ___ .. _____ . _ . ____ .. __ . _ .. ___ ... ___ ... _ _ _ 32 

chemungensis ...... __ .. ___ _ .: .... _ .. ___ .... ___ ... __ .. ____ .. __ 11,14 

hamiltonim ........ __ ---· __ .... ____ .... ____ .. ______ .. __ .. __ .. 19,74 

Maine, faunule at, designation of..~ .... ______ ... _ .. ____ .. __ ...... 10,31 

faunule at, elevation of.. ________ .. ____ .. _" ___ .. ____ .. ____ .. 10,22,31 

fauna of_ . __ ... ___ .. ___________ .... ___ .. ___ .... _ ..... __ . . . 22 

zone of ............. _ ...... ___ . ______ . ____ .. _ . ___ .. _ _ _ _ 10, 22, 31 

Marathon, section at ...... _ .... __________ .. ____________ .. _ .. ___ .. 29, 

section at, figure showing._ .. · ... _. ___ .... __ .. __________ .. __ .. 30 

Mesistrialis zone. See Spirifer mesistrialis wne. 

Messengerville, faunule at, designation of ...... ____ .. ____ .. ____ .. 10,31 

faunule at, elevation of .... ___ ..... __ .... __ .... ____ ........ 10,20,31 

K. fauna of .. _ ....... _ ..... _ . _ . _ ... ___ ... _ .. _ ... ____ . ____ .. _ _ 20 

Killawog, section at ............................................ __ 29 

section at, figure showing ......... _ ....... __ ...... _ ....... _... 30 

zone of ... __ .... _____ ... ______ .. ____ ._._. __ ... ____ .. _____ . 10,31 

section at ...... __ ..... _____ ... ___ .... ___ ...... __ ._ ... _ .... ___ . 29 

figure showing ..... ____ .. _. __ ._ ...... _ .... ___ ... _._...... 29 

L. l\fodiella __ .. __ . -·- _ .. ______ ... ____ .... _. ___ ... _____ .... __ .. ____ . _ _ _ 32 

Lapeer, faunule at, designation of. ........ : .. __ ..... ___ .... : _ .. __ 10,31 

faunule at, elevation of ................... __ ..... _____ .. 10,20-21,31 

fauna of .............................................. _.__ 20 

pygmma ... ·--- __ .. -·--··-- .. ·----· ____ ...................... 14,i4. 

Modiomorpha .. ____ .... _____ .... ____ . ____ ... __ . __ ... __ ... _ .... 32,34,35 

concentrica __ . __ .. __ .. ______ .. ____ .. _____ .... _ ............ 14120,74 

zone of ......................................... __ :. ______ 10,31 

J.,atty Brook, section at ............................. _____ . _______ 2i-29 

section at, figure showing ................. _ ..... ______ . _____ ._ 28 

Ledn. _. ___ ..... __ . _ ............................. _._ ..... _: ... _ _ _ _ _ .32 

macilenta _. ___________ . ________________ _ : .. ___ . _____ .. ____ .. 19 

mytiloides ......... ____ .. ______________ .. ____ .. _ ~ ______ .. ____ 14,21 · 

neg leota .... ____ .... __ :_ .... ____________ .. ____ .. ________ .. __ .. 11,12 

subalata ............. __ -------- ..... __________ .... ________ 11, 18,i4 

sp ........... _____ ...... -·---- .... ···--- ..... ... ....... .. .. .. . 20 Lcio ptcria. _. _______ .... ______ ... _ . __ . _ .... ____ .... _ , __ ... ___ . _ . _ _ 32 

conradi. ................................................... _ _ _ 21 

sp ............................... _ ..... ____ . _____ . _. 11-14, 16-19,22 

Monotrypa sp. _ ... _. ____ . ___ . _ .. _____ . _______ . ____ .. ____ . _ .. ___ . 13, 32 

Monotrypella. _ .. __ . ________ . _____ .. _____ ... ___ .... __ .... ____ .... 32 

grccni. ..... ____ ...... _. _ ..... _. ___ .. _ _. _____ . _______ . _ _ _ _ _ _ _ _ _ 20 

1ni tchell i ...... _ .......................... __ ..... _____ .. _____ . 20 

furcata ... _______________ . ____________ .... __ .... __ .... __ ... ... 14 

Mount Pleas:mt, faunule at, designation of ___ . ____ .. ____ .. ___ ._._ 10,31 

rnfincsqui ........................................... _ .... ____ 20,21 

sayi. ................................ -.- ...................... _ 20 

sp ........................................................... _ 1i 

Leiorhynchus._. ___ ........ __ ....... _ ........ __ ..... __ ._. ___ ... _. 34,35 

mcsicostale. _. __ .................. _ ....... __ ..... ____ 12, I i, 18, 20,32 

multicosta ............................................. 12,1i,18,32 

sinuatum ........................................... _ .. 11-14,16,32 

faunule at, elevation of. __ ...... ___ ... ____ .. ___ .. ____ .. __ .. 10, 16,31 

fauna of. ................... ___ .... _____ .. ______________ . _ Hi 

zone o( ....................................... ____ .. _ _ _ _ _ _ 10, 31 · 

Murchisonia .......... _____ . __ . _____ .. ____ ... __ ... ___ ., .. _ _ _ _ _ _ _ _ 32 

sp .......... · .......... ,·_ ........................ _ _ _ _ _ _ _ _ _ _ _ _ _ 15 

Muscular scar of pedicle val\·c, shape of, ratio index of ______ . . 4i 

size of, ratio index of. .... __ .. ______ .... __ .... __ .. ____ .. __ .... 4G-4i 

Leiorhynchus globuliformc zone, position of ... , ....... ___ ..... ___ 29,30 N. 

position of, figure showing ....................... _____ .. ___ 23,30,33 Narrow Bill, faunule at, designation of .............. ____ .. ____ .. 10,32 

Leptodcs1na ... ___ ........ __ .............. _ ...... __ . _ ... _____ . _. _ _ 32, 34 

agassizi. ...... __ ....... _ .................... _ .... ____ ..... ___ . 12 

faunule at, elevation of.. ______ ...... __________ .. __________ 10,15,32 

fauna of ............ __ .... ___ . _ .. ___ ... _ . __ ... __ ... ___ . _ _ _ 15 

creon ................... ___ --··············- .. ____ .. ____ .. __ .. 21 zone of-----.- .. ---.-------.---- .. -.-- ... -.--.---- .. --.--- 10,32 extenuntum .. __ ... _______ . _. _ ............ _ .... _ ...... _ ...... _ 14 

lie has .......... : ....... __ .......................... __ ... _ _ 13, 20, 21 

1nortoni. .. __ .. _. ____________ ....... _ ....... ___ .... ___ ... ____ . 13 

Nobles Hill, faunule at, designation of ..... __ .... __ ..... __ ... __ _ : 10,32 

faunule at, elevation of.. ______ .. __ .. ______ .. __ ..... _ ...... 10,13,32 

fauna of.._._ ....... __ .... ·._ .... __ .... _ .. _ ... ____ ... ______ 13 

potcns ........ _ ...... -. ___ ........ _ ........ __ .... ____ . ________ 21,22 

sp ..................... ___ ..... _. __ ...... ____ .. _______ . _ 13, 14, 16,20 

zone of ..................... ___ .... ___ .... ___ ... ___ ... __ . _ 10, 32 

Nomenclature, method of. ..... ___ .· .. __ ...... _ ..... __ .... _ .... _.. i 

J.,eptostrophia ncrvosa zone, position of, figure showing ... _______ . 28 North Candor, faunule at, designation of ..... _ ... ___ .. ___ .. ____ . 10,31 

IAn1optcra .. _ ..... __ . _ .. ____ . _ ..... ___ . _ . _ .. _______ .. _ _ _ _ _ _ _ _ _ _ _ _ 32 faunule at, elevation of.._ ..... ____ .... ___ . ____ . ______ ._ 10, 18, 19,31 

macroptcra ...................... __ ...... ____ ...... ___ .. ___ 15, 21,74 

Lingula .... __ ...... _ ................. _ . _ ..... _______ .. ___ . ______ . 32 

complanata ................. _ ... __ . __ -~ __ ... _______ .. _____ 13, 17,22 

spntulata _ .... __ ..... _____ .. __ ..... _ .. ________ .. _____ .. _____ . 12 

sp .... _ ... ___ ... ___ ..... _____ . _ ... _____ .... ______ ... __ .. 14,16,1 i,18 

Lisle, faunule at, designation of. .............. __ ...... ____ ....... 10,31 

faunule at, elc"l'ation of._ .. ____________________________ .. __ 10,21,31 

fauna of .................... ____ ....... __ ...... _._ .. :.____ 21 

fauna of._. __ ..... ___ .. _____ .. _. __ .. ____ .. ____ . _________ .. 19, 90 

zone of .............................. ____ .. _ .... __ ... _ . _ _ _ 10, 31 section at __ .. ______ .. _______ . __ ..... _ .. ___ ._. ____ ._. ___ ._____ 2i 

figure showing_ . _ .... _________ .. ____ .. _____ .. __ .... _ _ _ _ _ _ 2i 

North Chemung, faunule at., designation of.: ..... __ .... __ .... ____ 10,32 

faunule at, elevation of. __ .. _____ ." .. _______ .. ____ .. ____ .... 10, 14,32 

fauna of. ............ _ ..... ____ . ____ . _______________ . ____ . 14,91 

zone of .... __ ............... ___ .. ____________________ . _ _ _ _ 10, 32 

Nucula. _. _ ... _____ . __ ..... ___ .. _______ . _________ . _________ . _ _ _ _ _ _ 32 

zone of. ___ ... _ ........ __ . _ ... _ •. ___ ~ .. _________ . __ . ____ . _ _ 10, 31 

section at .. _ .. ___ ...... __ . __ ..... _________ ... _________ .. _____ 29-30 

corbuliformis ....... ____ .... ____ .... ______ .. ____ .. __ .... __ .. __ 12,20 

utnbonata .... _____________________ . ______ . ____ . _____________ . 13 

figure showing. _ ... _ .. ____ ........... _. _ ........ __ ....... 33 sp .. -.-------------- .... ---- .................... ________ .. __ 12,19 
102 INDEX. 

0. Page. 

Oakley Corners, faunule at, designation of.. ...................... 10,32 

faunule at, elevation of. ................................... 10,22,32 

fauna of. ................................................. 22,32 

zone of .................................................... 10,32 

~Ore~~:~:~~~~::::::::::::::::::::::::::::::::::::::::::::::::::::: u, ~~ sp ................................................. ~. 12, 13, 14, HHS 

Orthoceras .................. : .. : . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 

behryx .......................................... :............ 20 

sp.... .. .. .. .. ... . . . .. .. .. .. ... . .. .. .. ... . .. .. .... .. .. . . .. .. .. -15 

Osborn, faunule at, designation of.. ............................... 10,32 

faunule at, elevation of ................................. 10, 19, 20,32 

fauna of. ............. _.................................... 20 

zone of. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10, 32 

Owego, faunule at, designation of. ............................... 10,31 

faunule at, elevation of. ................................... 10,19,31 

fauna of.. ....................................... 19, 31, .94, 96, 98 

zone of ................................................... 10,31 

Owego quadrangle, faunules from ............... :., ......... 8, 66, 68, 73 

sections in ....... · ........... ·. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 

figure showing .............. 00 ........................... _ 27 

subdivision of. .............................................. . 

Owego zone, name of ............................................ . 

See al.~o 'rropidoleptus zone No.2. 

Palmoneilo bisuleata .......................................... 11, 32,74 

brevis ..................................................... 12, 17, 1,8 

plana.................................................... 32 

constricta. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... . . . . . . 20 

plana~ ................. , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 

sp .................................................... : .... 12, 18,20 

Paleogeography. See Geography, ancient. 

Paracardium......... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 

· doris ............................... :......................... 12 

Paracylas tennis.................................................. 13 

Paracyclas lirata zone, position of.. . .. . . . .. .. . . . . .. .. .. .. . . .. . . .. 29 

position of, figure showing .. 00 00 ................... · ........... 23,29 

Pedicle valve, muscular scar of. See Muscular scar. 

Phacops rana ............................................ S, 17, 19,32, 74 

Phthonia ...................... 00................................ 32 

cylindrica ........... · ......................................... 14, 74 

Platyceras ................ : . ............... :. . . . . . . . . . . ... . . . . . ... . 32 

conicum... ... . .. .. .. .. . . .. .. .... ... . .. .. .. .. . . .. .. . . .. .. . . .. 15 

erectum .................. · ................................ ·.·.. 15 

sp .................................... .-........... 13,14,17;18,20,22 

.Platyostoma..................................................... 32 

lineata ..................................... · .................. 14, 15' 

sp............................................................ 14 

Plenrotomaria ....................................... , .......... 32, 33,34 

capillaria .. 00 ..................................... 11, 12,14-16,18,74 

sp ................................................ 1:3,15-17,19,20,23 

Portage formation, recurrent zones in. . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 

recurrent zones in, figures showing ........................... 23-30 

See also Enfield shale member; Ithaca shale member. 

Productella .............. : . .............................. 32, 34, 35, 36, i:3 

boydi. ........................................................ 11,32 

hirsuta ........................... · ................... 11,13-15, li,32 

lacrymosa ..................................... 11, 12, 14-16, 19, 20,32 

, stigmata................................................. 18 

rectispina .....................................•.............. 11,32 

speciosa ............ : ......................................... 11,32 

spinalicosta ................................... 12,14,17-19,22,32,35 

sp ............................................................ 17,22 

I'terinea. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 

chemungensis. ... . .. .. ........................ ... .. .. .. .. . ... 23 

conshnilis.................................................... 13 

flabellum..................................................... 13 

reversa....................................................... 13 

R. 

Racial continuity, evidence of.. ............................. 00 ... 77-79 

Ratio indexes, scheme of. .................. 00.................... 44 

Hecurrence, discovery of. ...... , . .. .. .. . .. . . . .. . . . . . . . . . . . .. . .. . . 7 

evidence of ....................................... 34-36, 72-73, 75-79 

reliability of .............................................. 72-73 

Recurrent zones, fauna of. .. 00 ..... 00 .......... ·.· ................ 31-72 

fauna of, grouping of. 00 ......... 00 ........................... 31-33 

Pa.ge. 

Recurrent zones, stratigraphic positions of ..................... 7, 23-30 

figures showing ........................................ • 23-30,33 

thickness of .................................................. 30, 79 

See also Tropidoleptus zones. 

Rensselaeria 00 ..... 00 ...... 00 .................................... 70, 71 

Reticularia lrevis.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 

Hecticularia lmvis zone, position of. .............................. 24, 26 

position of, ftgure showing.................................... 24 

Rhipidomella ............................ 32,34,35,36,42-50,65, 72-75,77 

cyclas ..................................................... 44-4.j, 4s 

hybrida...... .. . .. . . .. . . . . . .. . . . .. . . . . .. . . . . . . . . . . . . . . .. . . . . . 46 

idoneus ............................... ·. . . . . . . . . . . . . . . . . . . . 44-45, 48 

leucosia ...................................................... 44-48 

pecosa........................................................ 46 

penelope ................... ·oo ............................ 44-49,90 

penniana .. ·. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 

vanuxemi. ......................... 8,11-19,21, 22,44-47,49,73,90-91 

sp .......... :. .. .. .. . .. . .. .. .. . .. . .. . . . . . . .. . . . . . . . . . . . . . . .. .. 12 

Rhipidomella genus, characters of.. .............................. 43-44 

characters of, ratio indexes of.. ............................... 44-47 

fluctuation of. ................................................ 48-50 

investigation of, scope of. . . . .. .. . .. . . . . .. . . . . . . . .. . . . .. . . . . . . 43 

oc~urrence of. ...................... 8,11-19,21, 22, 32, 34, 3.'), 36,70-77 

by quadrangles ......................................... 00 42 

by zones ..................... -.......................... -:. 42-43 

specific discrimination of ..................................... 47-50 

artificiality of ............................................ 47-48 

means of................................................. 48 

specimens of, measurement of. 00 ............................. 43-47 

selection of.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 

Rugose corals ............ , ............................. ·.......... 32 

s. 

Schizodus ..................................................... 15, 19, 32 

Sch~~~f!~~~-·.· ~::::::::: ~:::::::::::::::::::::::::::::::::::::. ~~' ~~~~~ Schuchert, Charles, on Alleghania............................. . . . 72 

Schuehertella. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 

chemungensis 00 00 00 00 00 ......................... 12-15,17,18,21,22 

Shell, shape of,_ratio index of ..................................... 44-46 

Sherburne member, section of, figure showing.............. . . . . . . 23 

Southport, faunule at, designation of ............................. 10, 13 

faunule at, elevation of. ................................... 10,12,31 

fauna of. ........................................... 12,31,94,96 

zoneof .............. ~ ............................. : ...... 10,31 

Spathella........................................................ 32 

sp...................................... .. . . . . . . . . . . . . . . . . . . . . 11 

Spencer, faunule at, designation of. .............................. 10,31 

faunule at, elevation. of. ................................... 10,13,31 

fauna of. ............................ :. . . . . . . . . . . . . . . . . . . . 13, 96 

zone of ................................................... 10, 31 

Spencer, east, faunule at, designation of .......................... 10,31 

faunule at, elevation of .................................... 10, 19,31 

fauna of.................................................. 19 

zone of ..... : . ................ ·. . . . . . . . . . . . . . . . . . . . . . . . . . . . 10, 31 

Spencer Lake ravine, faunule at, designation of. ................. 10,31 

faunule at, elevation of.............. . . . . . . . . . . . . . . . . . . . I 0, 12, 13, 31 

fauna of. ........................................... 12--:3,41-42 

zone of.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10, 31 

section in. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 

ftgure showing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 

Sphenotus ...................................... :................ 32 

sp ............................................. : . ............. 1.1, 13 

S pirifer augustus ........................ 00 .. .. . .. . .. .. . . . . .. . . .. . 59 

arenosus. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 

aspera ......................... 00............... ............. 56 

audaculns ........................................... 50,51, 53, 5ii, 59 

disjunctus ................................. 24,28,32,35,51,53, 71,78 

ftmbriatns ....................... · ...................... 17,22,32,74 

~:~~~~~f=~~~~~ ~::::::::::::: ~::::::: ~::::::::::::::::: "5i: 55:59,61' ~ clintoni ................................................... 59, 61 

sigma ................................ · ............... ·_. 61,61, 96 

hercynim... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71 

mucronatus ............................................... 13,51,59 

marcyi: .......... 8, 11, 12, 14-22,32, 34, 35, 36, 44, 5Q-G3, 65, 71, 73-78, 94 

alpha ........................................... 58-59,62,64,65 

beta ............................................... 58-65,94,96 
INDEX. 103 

Pu.ge. 

Spirifer marcy! delta ................................. 59-GO, 62-64,94,96 

epsilon ............................................. 00,62-G5,96 

gamma. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59, 62-G5, 94, 96 

:~;~~:·1~; .· ~ ~: ~::::::::::::::::::::::::::::::::. 58~9, ~:~: :~ zeta ................................................ 00,62-64,96 

medialis .................................................. 12, 13,32 

mesistrialis ................................... 20,32,50,51,52, 76,78 

ostiolatus .................................................... 50, .55 

oweni ............................ ~........................... 50 

parryana.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56, 00 

pmmatus ............ · ...................... 16, 20, 22, 23, 32, 65, 67,76 

posterus ............................ 18,20,32,65-67, 74, 76, 77,78 

radiatus... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 

ven1euili. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44, 56 

sp.... ...... .. . . . . . .. .. .. .. .. .. .. .. . .. . .. ........ ...... .. . . . . . 23 

Spirifer marcyi gens, classification of............................. oo 

differentiation of. ......................................... 50,5<Hi2 

evolution of .................................................. 53-65 

stages in .......................... · ........................ 64-65 

fluctuating characters of, diiTerentiatiop by ................... 56-62 

fluctuations of, degree of...................................... 56 

in zones 1 and 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51-52 

in zone 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52-53 

measurement of. ......................................... 56-58 

types resulting from ...................................... 58-GO 

)1istorical discrimination of ................................... 55-56 

nomenclature of.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 

occurrence of, in faunules ............ 8, 11, 12, 14-22,32,34,35, 36, 44,51 

recurrence of... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 

specific identity of ........................................... 54-55 

Spi.rifcr mesistrialis zone, position of .............. · ................ 24,29 

position of. figure showing ................................. 23, 24, 29 

Strophodonta cayuta .......................................... 11, 13,32 

Strophomena carinata ....... ! ................... ,................ 36 

Swartwood, section at ........................... ·................. 27 

soction at, figure showing..................................... 26 

Swartwood zone ................................................ . 

See also Tropidoleptus zone No. 3. 

Syringothyris, evolution of syrin.x in............................. 62 

figure showing............................................... 61 

Syringothyris typa. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96 

Syrinx, evolution of.. ............................................ 61-62 

evolution of, figures showing................................. 61 

T. 

'L'aghanic Ravine, section in...................................... 26 

soction in, figure showing .. ,.................................. 24 

Tentaculites................. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 

sp ............. : ........................................... 13, 18,20 

Tracy Creek, faunule at, designation of.. ......................... 10,32 

faunule at, elevation of. ................................ 10, 22-23, 32 

fauna of.................................................. 23 

zone of .............................. , . . . . . . . . . . . . . . . . . . . . 10, 32 

Tracy Creek, southwest, faunule at, designation of ............... 10,32 

faunule at, elevation of. ................................ , .. 10, 23,32 

fauna of.................................................. 23 

zone of .................................... ·. . . . . . . . . . . . . . . 10, 32 

'l'ropidoleptus .......................... , .......... 32,34-42,65, 70....75, 77 

carinatus ...................... : ....... 8, 11-23,36,37-42,73,76,86,88 

alpha .................................................. 37,38,88 

beta ................................................... 37,38,42 

delta..................................................... 37 

epsilon ................................................... 37,41 

ganuna ................................................... 37, 38 

typicalis .............................................. 37,38,88 

zeta ................................................... 38,39,42 

Tropidoleptus genus, continuit;y of............................... 36 

fluctuating characters of. ................. · .................... 37-42 

status of, in zone 1. .................. .' ................... 38-41 

in zones 2 and 3 ...................................... 41. 42 

Pagr.. 

Tropidoleptus zone No.1, fauna of. ..................... 86,88,90,91,94 

faunules in ................................................... 10,31 

dominant species in. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34, 35, 3!i 

position of. ....................................... 7, 23-24,27, 29,30 

figure showing ..................................... 23, 25, 27,33 

variation of Spirifer marcyi in ................................ 51-52 

variation of Tropidoleptus in .................................. ~8.:,41 

Tropidoleptus zone No.2, fauna of. ........................... 94,'96,98 

faunules in ................................................... 10,31 

domin!l,nt species in ................................... 34, 35,36 

position of. ............................................. 7, 24,27-29 

figure showing .................................. 23, 25, 26, 27,28 

variation of Spirifer marc:ri in ................................ 51-52 

variation of Tropidoleptus in ................................. 41-42 

'fropidoleptus zone No.3, fauna of. ........................ 91,94,96,98 

faunules in ................................................... 10,32 

dominant species in ....... , ............. .' ............. 34, 35,36 

position of. ............................................. 7, 24,27-29 

figure showing ..................................... 23, 25, 26,28 

variation of Spirifer marcyi in ................. -............... 52-53 

variation of Tropidoleptus in .................. : .............. 41-42 

Tropidoleptus zone of Ithaca shale member, existence of ......... 71-72 

fauna of. ..................................................... 90,98 

faunules in .................................... · ............... 10,31 

position of. ................................................ 7, 23,26 

figure showing ................. : ................... 23, 24, 29,30 

v. 

Van Etten, faunule at, designation of. ........................... 10,31 

faunule at, elevation of.. .......... : ....................... 10, 14,31 

fauna of. ................... :............................. 14 

zone of. .................................................. 10,31 

Van Etten zone, name of. ....................................... . 

See also 'fropidoleptus zone No. 1. 

Vaughan, A., defniition of gens by............................... 53 

\V. 

Watk-ins Glen quadrangle, location and parts of.................. 8 

section in, figure showing. . . . . . . . . .. . . . . . . .. . . . . . .. . .. . .. . . . . 23 

See also Watkins; Ithaca; Elmira; Waverly quadrangles. 

Watkins quadrangle, faunules from ...................... : .. 8, 66, 68,73 

subdivisions of............................................... 8 

\Vaverly, faunule at, designation of .............................. 10,31 

faunule at, elevation of.. ............................... 10, 15-16, 31 

f~unaof.............................. .................... 16 

zoneof ................................................... 10,31 

section at .................................... :............... 27 

figure showing. . .. . . . .. .. . . .. . .. . . . . .. . . . .. . . .. . .. . . .. . . . 26 

Waverly quadrangle, faunulcs from ......................... 8, 66, 68,73 

section in. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 . 

figures showing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25, 26 

subdivision of................................................ 8 

Wellsburg sandstone member, position of........................ 24 

section of, figure showing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 

West Datiby, faunule at, designation of. .......................... 10, 31 

faunule at, elevation of.. .............................. : ... 10, 12,31 

fauna of.................................................. 12 

zone of. .................................................. 10, 31 

section at.................................................... 27 

figure showing. . . . .. .. . . . . . . . .. .. . . . . . .. .. . .. .. .. . .. .. . . . 25 

White Church, faunule at, designation of. ........................ 10,31 

faunule at, elevation of. ................................... 10, 18,31 

fauna of. ............................................ : .... 18, 94 

zoneof. ........... : ................. · ................ -..... 10,31 

section at ............. ~...................................... 27 

figure showing........................................... 25 

\Vhittemore, faunule at, designation of ........................... 10,32 

faunule at, elevation of.. .................................. 10, 22, 32 

fauna of .................... ·.............................. 22 

zone of ................................................... 10,32 

occurrence of. ............................ 8, 11-23,32,34,42, 65, 70....75 z. specific characters or ......................................... 36-37 Zones. See Recurrent zones. 

0