DEPARTMENT OF THE INTERIOR

BULLETIN

OK THE

UNITED STATES

GEOLOGICAL SURVEY

TSTo. 165

WASHINGTON

GOVERNMENT PRINTING OFFICE

1900

UNITED STATES GEOLOGICAL SURVEY

CHAKLES D. WALCOTT, DIBECTOIt

CONTRIBUTIONS

TO THE

GEOLOGY OF MAINE

BY

HENRY S. Wir/LIAMS

AND

HERBERT E. GKREOORY

WASHINGTON

GOVERNMENT PRINTING OFFICE 

1900

CONTENTS.

 Page. 

Letter of transmittal.............................___..................... 9

Preface, by Henry S. Williams............................................ 11

Part J. The Paleozoic faunas of Maine: a preliminary report upon the Paleoj zoic faunas already known and upon new faunas recently collected 

{ from Aroostook County, by Henry S. Williams ................... 15

Part 31. Geology of the Aroostook volcanic area of Maine, including an account

of the clastic rocks of Aroostook County, by Herbert E. Gregory.. 93 

Part IJI. List of localities of Paleozoic, igneous, and other crystalline rocka 

examined during the seasons of 1897 and 1898, by Henry S. 

Williams..................................................... 189

' Index ................................................................... 205

5

ILLUSTRATIONS.

j

Page. 

PLATE I. Bhynchonellas of the Square Lake limestone...................... 64

II. Rhynchonellas of the Square Lake limestone...................... 06

~ ""X HI- A, Cleaved andesite, Edmunds Hill; J3, Hobart Hill; massive andes-

" - ,. ite exposed by erosion ........................................ 101

IV. Map of Aroostook volcanic area................................... 105

V. A, Spherulitic rhyolite from Haystack Mountain; B, Vesicular lava

from Haystack Mountain...................................... 107

VI. A, "Birch bark" weathering of rhyolite; B, Transverse section of

same ...........i............................................. 108

VII. A, Andesitic lava; B, Andesitic breccia........................... 1.12

VIII. A, Fine-grained Sheridan sandstone; B, Sheridan sandstone ....... 132

IX. A, Conglomerate of the Sheridan sandstone series; B, Sandstone from

Madawaska Lake ............................................. 134

X. A, Railroad cut at Houlton, showing slated Aroostook limestone; 

B, Railroad cut at Timony road, showing folded and faulted 

Aroostook limestone ............."............................. 140

XL A, Bandqd limestone; B, Aroostook limestone .................... 142

XII. A, Mapleton conglomerate; B, Manganiferous iron slate ........... 144

XIII. A, Perlitic type of rhyolite; B, Area between spherulites, perlitic

type of rhyolite............................................... 158

XIV. A, Vesicular lava; B, Volcanic tuff................................ 160

FIG. 1. Index map of area described ...................................... 12

2. View of Haystack Mountain....................................... 107

3. Diagram of Haystack Mountain.................................... 109

4. Section on Mapleton-Presque Isle road............................. 113

5. Map of part of Mapleton Township, showing the teschenite area...... 116

6. Map of Castle Hill area ........................................... 120

7. Section at Mars Hill:...............,............................. 135

8.' Section through Winslows Hill.................................... 137

-9. Microcline and orthoclase intergrowth ............................. 149

10. Zonal intergrowth of microcline and orthoclase..................... 150

11. Optical measurements of a plagioclase crystal....................... 182

7

LETTER OF TRANSMITTAL.

YALE UNIVERSITY,

New Haven, Conn., September 19, 1899.

SIR: I have the honor to transmit herewith a report including the 

following Contributions to the Geology of Maine, viz: Part I, The 

Paleozoic faunas of Maine, by Henry S. Williams; Part II, Geology 

of the Aroostook volcanic area of Maine, by Herbert E. Gregory; and 

Part III, List of localities of outcrops of Paleozoic and igneous rocks 

in Aroostook County examined in the years 1897 and 1898, by Henry 

S. Williams; and have to request that it be published as a bulletin of 

the Survey.

Yours, respectfully,

HENRY S. WILLIAMS. 

Hon. CHARLES D. WALCOTT,

Directs U. S. Geological /Survey.

PREFACE.

The investigations reported upon in this bulletin were begun primarily for the purpose of ascertaining the facts regarding the local 

modification of the Devonian and Silurian faunas in the eastern province of North America. They were authorized by the Director of the 

Survey in a letter dated June 16, 1897, in the words: "Your special 

work will be the investigation of the Paleozoic rocks and fossils of 

eastern and northeastern Maine."

The Canadian Survey had already reported upon the Anticosti and 

Gasp6 series, from the region beyond Maine to the east. In Nova 

Scotia the Arisaig and Nictaux series present -another phase of the 

problem. Hitchcock, Shaler, and others, and, in Canada, Billings, 

Bailey, Mclnnes, Ells, and Ami, have gathered information here and 

there regarding the,, faun as occasionally met with in the region. It 

seemed greatly to be desired that careful collections should be made 

in the Maine territory, to serve as a basis for comparison between the 

typical expression of the Paleozoic faunas in New York State and 

those described from the eastern provinces of Canada, and also as a means 

of comparing the American with the European phases of the Paleozoic. 

Ten years ago a beginning was made toward carrying out this plan, 

and collections were made in Somerset County (see fig. 1, p. 12). They 

alone did not throw much light upon the succession of Paleozoic faunas, 

and the work was resumed in 1897.

The field work in Aroostook County (see fig. 1) was done in the summer months of 1897 and 1898; in the former year by Dr. Herbert E. 

Gregory and myself and in the latter year by Dr. Gregory alone. In 

1897 the localities north of the Aroostook were examined by me, those 

south of the river partly by Dr. Gregory alone, and the more northern 

townships by both of us together. In 1898 Dr. Gregory reexamined 

the volcanic area, to gather special facts for his part of the report 

(Part II). The p^trographic study of the materials gathered was made 

under the direction of Prof. L. V. Pirsson in the mineralogical laboratory of Yale University. The results of his investigations were written by Dr. Gregory substantially in the form now appearing as Part 

II of this report, and were offered to and accepted by the faculty of 

the graduate department of Yale University for the degree of doctor 

of philosophy, given him in June, 1899.
12 PREFACE.

The collections from Somerset County were made for the Survey in 

1889 b}^ Mr. Gilbert Van Ingen under my direction. Several collections 

of fossils, including the fine one from Square Lake, were made by Mr. 

Olaf O. Nylander, and secured for the Survey.

^>

FIG. 1. index map showing tne locations described in tnis report. The larger shaded area 011 the 

right is the Aroostook County area referred to in Parts I, II, and III. The small black rectangle in 

the midst of the shaded area is the volcanic district reported upon in Part II. The smaller shaded 

area on the left side is the Somerset County area.

All the fossils have been examined by me personally, and the report 

on the faunas (Part I) constitutes a preliminary report on the geologic 

results of such study. Many of the species are new species or varietal
PREFACE. 13

forms. Their paleontologic description is reserved for future publication.

A few well-defined formations, with their faunas, have been elaborated. The fossils, though few and imperfect, and in almost every 

case varying more or less from the typical species familiar to us from 

the sections in the interior of the continent, have been identified with 

sufficient certainty to make their general stratigraphic position evident.

In this preliminary report the listing of species has been made pri- 

 marily with the view of bringing out the geologic facts. In many 

cases, as just stated, the forms do not'exactly agree with any of the 

described species of the New York or interior region. In such cases 

identification has been given with the species to which the resemblance 

is closest. When it is noted that a remarkable number of new species 

were found by Billings in both the Gaspe" and the Square Lake faunas 

differing at least varietally from any other known species in America 

or Europe it will not scein strange that these Maine faunas should 

contain many species which can not be exactly identified with any that 

have been described. However, a few of the species of each fauna 

have been identified with known species, making the stratigraphic 

position evident. To determine the horizons with greater precision, a 

thorough biologic study of each fauna and its comparison with typical 

"European as well as American collections will be required.

In lists of species here given, the sign cf. (confer} is frequently 

employed to indicate that the name used is that of a species already 

described with which the specimen named closely agrees but is not 

strictly identical. For the same, reason no attempt is made to give 

the name of the true author of the species. The lists are given for 

geologic rather than biologic purposes.

Lists of "faunas obtained from Maine, New Brunswick, and a few 

other localities, and already reported upon, are introduced, as given 

in the original reports, for reference in correlating the terranes. The 

typical New York faunas are not reproduced, as they may be easily 

obtained from standard reports. The collections are all numbered 

and the fossils are in process of paleontologic study for final description and illustration. Many of them are already figured. Samples of 

the Square Lake fossils are 'given on Pis. I and II (pp. 64, 66). The 

original figures reproduced on these plates were made by a new, 

patented photographic process, directly from the specimens, by Mr. 

N. W. Carkhuff.

At the beginning of our investigations I had expected to obtain 

sufficient knowledge of the stratigraphy of the region to interpret the 

true succession of the various terranes. The remarkable scarcity of 

fossils, the heavy sheet of drift, and the general fractured, disturbed, 

and semislated state of the rocks have left little reliable evidence of 

original structure to work on, It has been impossible, therefore, with
14 PEEFACE.

present knowledge, to determine the precise areal distribution of 

the several formations, although the facts as to the structure and the 

stratigraphic sequence of the rocks are given whenever they are conclusive. More detailed study of the region must be made before the 

areal geology can be mapped with any degree of precision.

The map (PI. IV) prepared by Dr. Gregory indicates the general areal 

distribution of tHe clastic rocks in Aroostook County, so far as we have 

observed them. The belts of similar rock have a general northeastsouthwest trend. The Aroostook limestone is on the east, the arenaceous limestones and shales are next westward, and the more sandy 

Sheridan sandstones are in the western part of the area; but this does 

not accurately express the distribution of the formations, for in the 

region marked as sandstone are found not only the Ashland limestone areas, but slates that are undoubtedly older than the Sheridan 

sandstone, which contains pebbles of apparently these same slate rocks.

Because of the uncertainty regarding the true sequence of the clastic 

formations, Dr. Gregory has classified them (in Part II) purely on 

petrographic characters. This gives the facts which will make their 

areal mapping possible, but leaves their classification on a stratigraphic 

basis to be completed when further evidence regarding the sequence 

has been obtained.

The description of the physical and lithologic characters of the rocks 

and geologic formations will be found in Part II. A list of all the 

localities in Aroostook County examined by Dr. Gregory and myself 

is given in Part III.

The collections here reported upon were made by Gilbert Van 

Ingen, Olaf O. Nylander, Herbert E. Gregory, and myself, and are now 

the property of the United States Geological Survey. We are indebted 

to Mr. Nylander for pointing out numerous localities along,the roads, 

in ou't-of-way places, where he had discovered outcrops, and we 

are particularly indebted to him for knowledge of several important 

exposures containing fossils. Mr. Nylander is a keen observer, and 

deserves great credit for the discovery of fossil localities which it 

would have taken much time and labor to locate without his preliminary work.

For many courtesies we are indebted to the officials of the Bangor and 

Aroostook Railroad, and the State land office, and to numerous landowners whose farms we invaded in the course of our surveys, and who, 

in many cases, took considerable pains to promote our investigation.

H. S. W.
CONTRIBUTIONS TO THE GEOLOGY OF MAINE

Part I THE PALEOZOIC FAUNAS OF MAINE

A PRELIMINARY REPORT UPON THE PALEOZOIC FAUNAS ALREADY 

KNOWN AND UPON NEW FAUNAS RECENTLY COLLECTED FROM AROOSTOOK COUNTY

BY

HENRY S. WIIXIAMS

.15

CONTENTS'OF PART I.

Page.

Classification of the Paleozoic terranes of Aroostook County ................. 21

Paleozoic faunas already reported from Maine and bordering regions ........ 27

Localities in Maine................................................... 27

Waterville.................................................... 28

Machiasport .........................,.....'................... 28

Lubec lead mines............................................. 28

Davis Point.................................................. 28

Pembroke ................................................... 29

Parlin Pond and Moosehead Lake ............................. 30

Seboois River to Presque Isle.................................. 30

Perry........................................................ 31

Square Lake ................................................. 31

Telos Lake .................................................. 33

Cobscook Bay series.............................................. 34

Orange or Whiting Bay....................................... 34

Dents Point.................................................. 34

Dennysville. ................................................. 35

Moose Island ................................................ 35

North Haven series of Penobscot Bay.............................. 35

Localities in Canada.................................................. 37

Campbell River, Arictoria, New Brunswick ..................... - 37

Saint Helens Island, near Montreal, Canada.................... 37

Gasp6 series..................................................... 39

Arisaig, Nova Scotia.......................................... 40

Some additional faunas closely allied to Maine Paleozoic faunas.............. 42

Oriskany of Becraft Mountain, New York...................... 42

Baileys Landing, Perry County, Missouri.... ^................. 43

Clear Creek, Union County, Illinois ........................... 43

Jonesboro, Union County, Illinois............................. 43

New Paleozoic faunas from Aroostook and Somerset counties, Maine......... 44

Aroostook limestone.................................................. 44

Graptolite shales ..................................................... 45

Sheridan sandstone................................................... 47

Sheridan Plantation.......................................... 47

New Sweden................................................. 48

Drift bowlders ............................................... 48

Ashland shales....................................................... 49

Ashland Village.............................................. 49

Winslow farm................................................ 50

Ashland limestone.................................................... 52

Ashland Village.............................................. 53

Ashland, Gilman farm........................................ 53

Ashland, Winslow farm ...................................... 53

Bull. 165 2 17 '
18 CONTENTS OF PART I.

New Paleozoic faunas from Aroostook and Somerset counties, Maine Cont'd. Page.

Ashland limestone Continued.

Castle Hill, Dudley farm...................................... 53

Chapman, Littlefieldfarm..................................... 54

Fort Fairfield and Presque Isle...... .......................... 54

Square Lake limestone................................................ 54

Correlation of the rhynchonellas-of the Square Lake fauna.......... 56

Generic characters ........................................... 56

Species of rhynchonellids in the Square Lake fauna ............ 67

Chapman sandstone.................................................. 78

Presque Isle Brook........................................... 78

Edmunds Hill.................................................. 79

Presque Isle and Mars Hill.................................... 79

Mapleton sandstone .................................................. 88

Moose Eiver sandstone................................................ 88

Parlin Pond.................................................. 89

Jackman farm................................................ 90

Bean Brook,................................................. 90

Long Pond................................................... 90

Little Brassau Lake. ........................................... 91

Stony Brook......................................... . ...... 91

Big Brassua Lake............................................. 91

BrassuaStream .................... .....'.. ................... 92
ILLUSTRATIONS IN PART I.

' Page. 

PLATE 1. Rhynchonellas of the Square Lake limestone.................... 64

II. Rhynchonellas of the Square Lake limestone.................... 66

19

CONTRIBUTIONS TO THE GEOLOGY OF MAINE.

PART I, THE PALEOZOIC FAUNAS OF MAINE,

By HENKY S. WILLIAMS.

CLASSIFICATION OF THE PALEOZOIC TERRANES OF 

AROOSTOOK COUNTY.

Recent investigation of the rocks of the northern part of Aroostook 

County has brought to light a few facts regarding the stratigraphicf 

terranes, which may be stated with some degree of precision.

There are a few well-marked groups of rocks which are distinguishable by their lithologic characters, and the relative age of which is 

determined by their contained fossils. The order which the present 

knowledge of the faunas seems to indicate is as follows:

9. Mapleton sandstone .....

8. Moose River sandstone. .} = Devonian.

7. Chapman sandstone .... -|

6. Square Lake limestone..

5. Ash land limestone......

4. Ashland shales......

3. Sheridan sandstone.. 

2. Graptolite shales....

1. Aroostook limestone.

= Silurian.

Below "the Aroostook limestones are slates, which it is believed are of 

Cambrian age, but positive evidence of the age is wanting.

The lower seven belong to the Silurian; the upper two to the Devonian. The paleontologic evidence is clear in placing 1-5 below the 

Lower Helderberg horizon of the New York series.

The Aroostook limestone, on both stratigraphic and paleontologic 

grounds, is believed to be older than any other of the terranes mentioned in this list.

The Ashland limestone, Ashland shales, and Sheridan sandstone are 

faunally closely associated, and belong logether as the representatives

of the Clinton-Niagara of the New York standard.

21
22 CONTRIBUTIONS TO THE GEOLOGY OF MAINE. [BULL. 165.

The Graptolite shales, the writer believes to be of Clinton age, but 

their stratigraphic position in the Maine series is not satisfactorily 

established. They may belong in the midst of the series ^ 4, 5, or even 

above them; more evidence will be needed to determine their position 

with certainty.

The Chapman sandstone fauna is younger than the Square Lake 

fauna; the present opinion is that it corresponds closely with the Lower 

Oriskany of the New York and interior series. The identification of 

the fauna with Honeyman's Zone D Arisaig and with the "Tilestone" 

fauna of Wales establishes its place at the top of the Silurian (see 

Am. Jour. Sci., 4th series, Vol. IX, p. 203).

The Moose River fauna is. a facies of the Eodevonian, and represents 

the Oriskany.

The Mapleton sandstone is the representative of the higher parts of 

the Gaspe sandstone, and is the Old Eed sandstone facies, not expressed 

in New York until a point higher up, in the Catskill sandstone, is 

reached.

Besides these terranes, determinable by their fossils, there are slates 

and crystalline rocks, the precise age of which is undetermined. The 

slates are presumably Cambrian or pre-Cambrian.

In the paper prepared by H. E. Gregory (Part II) the several terranes are described from a lithologic and petrographic point of view. 

In the following pages (Part I) the faunas are described and grouped 

together in the combinations suggested by their contents and by the 

character of the rocks containing them. In the two papers combined 

are presented the preliminary results of the writers' investigations, so 

-.far as they concern the interpretation of the geology of the regions 

studied. Many problems are raised which will require further petrographic and paleontologic investigation for their solution.

For purposes of comparison the typical sections of the Silurian and 

Devonian of the Canadian survey, including the Anticosti Island and 

the Gaspe Peninsula, are important. The interpretation of these sections was made by Sir William Logan, and was reported in a summary 

form i n the Geology of Canada. The sections of particular importance, 

for the present purpose, are Nos. 10 and 11 of PI. IV.

Section No. 10 is described in the text as follows: 1

This line extends from Ste. Anne des Monts, on the south bank of the Gulf of St. 

Lawrence, in a south-southeast direction across the Peninsula of Gaspe" to the mouth 

of the Great Cascapedia River on the Bay of Chaleurs. Commencing wife the Quebec 

group, it crosses the Shickshock Mountains, which are formed of altered Sillery rocks, 

and the Barn-shaped Mountain, an intrusive mass of trachytic granite. It then 

traverses a great breadth of Upper Silurian, which rests unconformably upon the 

Quebec rocks, and presents two subordinate basins, in both of which appears tl.e 

great Gasp6 sandstone formation of Devonian age. This, in the southern basin, on 

the Bay of Chaleurs, is seen to be unconformably overlaid by the Bonaventure formation belonging to the Carboniferous period. The whole length is 68 miles.

1 Geol. Survey Canada. Report of progress from its commencement to 18C3. Atlas of maps and sections, 1863, PI. IV, and text of explanations, p. 26.
WILLIAMS.] CLASSIFICATIONS.

The classification is given in the index of the chart as follows: 

22. Bonaventure ................................................Carboniferous.

19- \r- x j x /Chemung ..........X ^

., fGaspe sandstones =S rv ., f................_.-Devonian. 17. J lOriskany..........J

16. Cape Gaspe" limestones = Lower Helderberg i

15. Port Daniel limestones = Onondaga? ...... l=Gaspe" limestones.Upper Silurian.

12. Chatte Eiver limestones = Clinton ........ J...................Middle Silurian.

6. Sillery = Chazyl _. . T c,., .

., , .; J f= Quebec ................................... Lower Silurian. 5. Calciferous ... J

Trachytic granite............................................ .Intrusive.

Section -No. 11 is defined as follows: l

This line from the Laurentian of the main land to the north of the Mingan Islands, 

on the north shore of the Gulf of St. Lawrence, passes southeast across the water of 

the gulf to Anticosti, thence southwest across this island to Gasp6 Bay, and finally 

south to Cape d'Espoir, on the bay of Chaleurs. Showing portions of the Lower 

Silurian rocks in the Mingan Islands, it exhibits the Middle Silurian in Anticosti, 

and the rocks of the Quebec group, brought up by a fault near Cape Rosier, in Gasp6. 

Reposing uncomformably upon these we have, as in the last section, a great basin of 

the Gaspe" limestones and sandstones, exhibiting several faults and undulations, and 

holding in two of the subordinate basins portions of the nnconformable Bonaventure 

conglomerate. The length of this section is 161 miles.

The index of the chart is as follows: 

22. Bonaventure...................................................Carboniferous.

19' JGaspe sandstones..( Chemung X ..............................Devonian.

17. / I Oriskany /

16. Cape Gaspe limestones ........ ] -^ Helderberg . .ujpper

( Port Daniel limestones....... Gaspe limest. |0nondaga (LucUow) /Silurian.

' IL'Anse a la Veille limestones. '

12. Southwest Point limestones.... 1) A ,-, ( Clinton --.-- ) ,., ., . 11 T * nrwv t. I Anticosti... J ^ Middle Slur an. 11. Junction Cliff limestones ....../ X Medina....../

10. Hudson Eiver...................

9. Utica.... ........................

8. Trenton.........................

7. Birdseye and Black River.......................... 1........ Lower Silurian.

6. ChaZy......| Quebec _

5. Calciferous. J

4. Potsdam ........................

1. Gneiss...................................................... Laurentian.

The classification adopted on the general map is given on page 18 of 

text, and is in part as follows: 

22. Bonaventure conglomerate. 

21. Lower Carboniferous limestone. 

20. Old red sandstone ...............

19. Chemung and Portage ...........

18. Hamilton .......................

17. Oriskany and Corniferous ........

16. Lower Helderberg...............

15. Onondaga.......................

14. Guelph .........................

13.. Niagara......................... Middle Silurian.

12. Clinton .........................

11. Medina and Oneida.

Etc. ______

1 Geol. Survey Canada. Report of Progress. Atlas. 1803. I'l. IV and text, 7 explanations,p.26.

Gasp6 sandstone .. Devonian.

V Upper Silurian

Gaspe" limestone ..
24 CONTRIBUTIONS TO THE GEOLOGY OF MAINE. [BULL.1C5.

The classifications and correlations of these Anticosti and Gaspe formations remain substantially as they were given in this report in 1863. 

In the body of the work the Anticosti group is defined as follows:1

The remaining portion of the island is occupied by newer rocks, to which the 

name Anticosti group has been given. Their position in the geologic series is that 

occupied by the Oneida conglomerate, the Medina sandstone, the Clinton group, and 

the Niagara group of the New York geologists; but these subdivisions, although 

apparent in the western basin, disappear in the Anticosti strata, which are lithologically unlike their equivalents in western Canada.

This last remark also applies to the corresponding formations of 

Maine. The Maine terranes, numbered 1 to 5 in the list alread}^ given, 

although their age is clearly Eosilurian, differ from the New York 

terranes both in their stratigraphy and in the composition of the faunas.

The limestones of Cape Gasp6 appear to be a great development of strata of the 

age of the Lower Helderberg group. The fossils at the summit, however, bear a 

striking resemblance to those of the Oriskany formation, with which several of them 

are identical. It appears probable, therefore, that we have here a passage from the 

Lower Helderberg to the Oriskany, and the latter formation may be more especially 

represented by the lower part of the Gaspe" sandstones. The organic remains discovered in these sandstones are as yet too few to enable us to separate the series into 

distinct members. We have already mentioned that a species of Rensselasria, identical with or closely resembling R. ovoides, which occurs in the upper part of the limestones, is met with at 1,100 feet above the base of the sandstone series. This fact, 

together with the constancy in the lithological characters of the latter, makes it not 

improbable that at least this lower portion of the sandstones will ultimately be classed 

with the Oriskany formation.

.In the land plants there appears to be but little difference from the commencement 

of the series to the base of the red sandstones, a thickness of over 5,000 feet. These 

strata present analogies with the whole series of formations in New York, from the 

Marcellus shales to the summit of the Chemung sandstones, in all of which, according to Dr. Dawson, are found several of the species of plants that occur in the Gasp6 

sandstones. The whole of these 5,000 feet resemble, lithologically, the Portage and 

Chemung sandstones of New York, and it may hereafter be found that in this eastern part of the continent the Oriskany, fauna, which occurs at the base of this Devonian series, merges gradually, toward the summit, into that of the Portage and Chemung group. In lithological characters the remaining upper 1,800 feet of the Gaspe" 

series resemble the Catskill group of New York, which is regarded by Mr. Hall as 

the base of the Carboniferous system. As yet, however, no comparison can be 

made by fossils; those found in Gasp6 being chiefly confined to a few obscure 

plants. 2

On passing westward the formations lower than the typical Gaspe 

limestone of Cape Gaspe come into sight. "On the Chatte and 

Matanne rivers, on Lake Matapedia, and on the rivers Metis and 

Rimouski, the lower portion of this series of limestones appears to 

belong to the Anticosti group." 3

. This connection of the representatives of the Clinton-Niagara series 

directly upward with those of the Lower Helderberg, without indi1 Geol. Sutvey Canada. Report of Progress, 1803, p. 298. 3 Op. cit., p. 390.

2 Op. Cit., pp. 391, 403-404.
WILLIAMS.] THE SILURIAN-DEVONIAN TRANSITION. 25

cation of any rocks or faunas to be correlated with the Onondaga or 

Guelph, is confirmed by the Maine series of faunas and formations. As 

far west as St. Helens Island, Lake Meinphremagog, and Dudswell, in 

Quebec Province, where the Silurian is recognized by occasional fossilif erous rocks, everything at present reported points to a geologic 

history in common with the Anticosti and Gaspe regions, and not in 

conformity with the events recorded west and south of Hudson .River.

In classifying the Maine faunas, closer correlation is to be expected 

with the faunas of the eastern province than with the Appalachian or 

interior provinces. Not only do the Maine faunas agree in general 

sequence and composition with those of this eastern province, but this 

fact is of great significance in correlating American with European 

systems.

The boundary between the Silurian and Devonian systems was first 

made in the Welsh series, in which the transition was from calcareous 

sedimentation, with rich and purely marine faunas, into sandstones of 

great thickness containing land plants and fishes whose habitat was, 

presumably, fresh or brackish waters.

The New York section, from the Lower Helderberg limestones 

through the Oriskany, Cauda-galli, and Schoharie grits back again into 

limestones, does not pass out of marine conditions. In the Gaspe 

region, however, there is a complete change (as there was on the other 

side of the Atlantic Basin) at the point where the Oriskany fauna was 

evolved. In these Silurian faunas of the eastern province there is 

also much closer resemblance to the Wenlock-Ludlow series than is 

found in the faunas of the Appalachian province in New York. The 

correlation of the passage beds at the top of the Silurian of Wales is 

clearly to be recognized in the passage from the Gaspe* limestones to the 

Gasp6 sandstones of the eastern province of America. This Gaspe" 

transition is also to be traced with precision to the horizon of the introduction of the Oriskany fauna into the basins farther west and 

southwest, in which no direct passage into Old lied sandstone-condition 

is apparent.

We have thus in America a means of determining where the Silurian boundary belongs in purely marine series of beds and among 

marine faunas of unbroken succession. The Lower Helderberg in the 

interior of the American continent, as the Koniprusien F2 fauna in 

the Bohemian Basin of Europe, is closely related in its species to what 

succeeds, because there was no radical disturbance of the conditions of 

marine life. Nevertheless, it is not the Lower Helderberg species 

that mark the conditions corresponding to the beginning of the Old 

Red sandstone; but the changes which that fauna suffered during the 

passage into the Oriskany time are evidences of a general disturbance 

which resulted in the lifting of large areas of marine surface above the 

level of the sea.
26 CONTRIBUTIONS TO THE GEOLOGY OF C MAINE. [BULL. 165.

Taxonomically, we are able to indicate with precision the point in 

America at which this change from the Silurian to the Devonian systems occurred. However many species may have survived the change, 

the time of income of the peculiar Oriskany species in Gasp6, New 

York, and the Appalachians is to be correlated with the Gedennien 

sandstones and shales of the Rhenish provinces, which hold a sparse 

but strictly marine fauna, with the corresponding grits of South Devon, 

with the plant-bearing Foreland sandstones of North Devon, and with 

the base of the Old Red sandstones of Wales, northern England, and 

Scotland. This point can be seen in any section in which the fossils 

are preserved, and furnishes for America one of the most definiteboundaries wherever the Oriskany fauna appears.

This transition in the faunas is evident in all the sections in which 

the Oriskany appears. In this eastern province the termination of 

the marine faunas occurs at the same place in the faunal succession 

that was adopted by Murchison as the boundary line between the Silurian and the Old Red sandstone.

Thus in America we have the means of determining the original 

upper boundary of the Silurian where it passes into the equivalent of 

the Old Red sandstone, and we are able to locate the Lower Helderberg positively in the Silurian system, in spite of the fact that the 

typical Lower Helderberg fauna of New York presents close affinities 

with the earlier marine Devonian faunas of Europe.

Having thus determined for America the taxonomic equivalent for 

the original boundary between Silurian and Old Red sandstone in 

Wales, the fixing of the boundary in sections in which the marine 

faunas continue upward to form a Devonian instead of an Old Red system is a matter of local correlation. The Gaspe* and Square Lake 

limestones of Maine both contain unmistakable evidence of the Lower 

Helderbere; fauna of New York, and both of these limestones occur O '

below the boundary line. The Lower Helderberg is, therefore, proved 

to belong to the typical Silurian system of the American continent.

The question of the relation of the species of the Lower Helderberg 

fauna to lower or higher faunas in America does not enter into the 

problem. Wherever in the sequence the local conditions continued 

uniform, it is reasonable to suppose that the successive faunas suffered 

very slight and slow modification with the passage of time.

On the other hand, any grand geologic event which disturbed the 

relations of land to sea over wide territory would naturally be expressed 

in more or less complete changes in the composition of the successive 

faunas.

Nor is it safe to give too much weight to the evidence of apparent 

similarity of faunas in'regions so distant as central Europe and the 

North American continent. It may be true that the Lower Helderberg fauna resembles the Hercynian fauna in its genera and types of
WILLIAMS.] HITCHCOCK'S REPORT. 27

species more than it does the typical Ludlow. Were this true, as 

claimed by some European geologists, the actual likeness is no greater 

than that between the Wenlock and Ludlow faunas, one of which is 

known to succeed the other.

Looking at all the evidence and giving all respect to the opinion of 

European geologists, the writer is forced to believe that the evidence 

of the Maine and New Brnnswick faunas confirms the correlations of 

De Verneuil, Sharp, Bixby, and Hall and Logan as to the place of 

the,boundary line between Silurian and Devonian in North America, 

and positively shows the Lower Helderberg to lie below that boundary 

line. 1 .

PALEOZOIC FAUNAS ALREADY REPORTED FROM MAINE 

AND BORDERING REGIONS.

Paleozoic faunas have been recognized in Maine by various authors, 

and a few localities have furnished lists of species already published. 

Before reporting the additions recently made, a brief statement of each 

of the various, fossiliferous localities and the lists of species already 

reported from them will be given. No attempt Avill be made at present to revise these lists. The faunas from Gaspe and a few other 

localities are added, in order that the reader mny have before him-for 

comparison the facts at present accumulated which. bear upon the 

geologic classification of the Paleozoic rocks of this region.

LOCALITIES IN MAINE.

A paper entitled Notes on the Geology of Maine, prepared by 

C. PL Hitchcock, State geologist, was read before the Portland Society 

of Natural History on March 3, 1862, and subsequently published in 

its proceedings. 2 The paper refers 1,0 the collections made by the 

author in the previous summer (1861) and placed in the hall of the 

societ)r. Preliminary lists of the fossils are given. Some passages 

in this report are also found m the Agriculture and Geology of 

Maine, which, from internal evidence, 3 appears to have been published 

in 1862, though the date on the title-page is 1861. It is not evident 

whether the manuscript of the Agriculture and Geology report 

was handed in at the time of reading the paper above mentioned, or 

the paper was read first. The report in Agriculture and Geology

1 Since the above was written a fuller study of the fauna of the Chapman sandstone has been made, 

and its close correlation established with the fauna of Zone D of Honcyman's upper Arisaig, 

which was identified by Salter with the Ludlow Tilestone fauna of Wales. The results of these 

studies were given in a paper read before the Geological Society of America in December, 1899. A 

paleontologic discussion of the fauna is published in the American Journal of Science for March, 

1900. (See the Silurian-Devonian boundary in North America; 1. The Chapman Sandstone fauna: 

Am. Jour. Sci., 4th series, Vol. IX, pp. 203-213.) H.S. W., April 3,1900. (See p. 80.)

- Vol. I, Ft. I, pp. 72-85.

"The date of publication of the Report on Agriculture and Geology (second series for 1801) is indicated to be as late as 18G2 by the date of the secretary's report, which is "January, 1802" (see p. 89).
28 CONTRIBUTIONS TO THE GEOLOGY OF MAINE. [Buu.,165.

is the fuller, and it is taken as the standard report of the facts in 

question.

The fossils, rocks, and minerals of the collections referred to were 

destroyed by fire in 1866. The lists and identifications of the fossils 

are hence of special importance, as the originals are not in evidence.

In this Sixth Annual Report of the Board of Agriculture for 1861 l 

is included a General Report, upon the Geology of Maine, written 

by C. H. Hitchcock. 2 In the latter part appear lists of fossils from 

various localities in Maine, which were identified by E. Billings, 

Emmons, and Sir William.(J. W.) Dawson.

Waterville. The following species of plants were reported by Emmons from the clay slates of Waterville, Maine, 3 referred by Hitchcock 

to the Lower Silurian formation:

1. Nereograspus Jacksoni.

2. Nereograspus loomisi.

3. Nereograspus deweyi.

4. Nereograspus gracilis.

5. Nereograspus lanceolatns.

6. Nereograspus pugnus.

7. Myrianites murchisoni.

8. Myijianites sillimani.

Machiasport. At Machiasport, at the Point of Maine, Washington 

County, in dark calcareous slaty rocks underlying red sandstone, are 

reported the % following fossils, determined by Billings, and classified 

by Hitchcock as Upper Silurian:*

1. Modiolopsis.

2. Avicula.

3. Pleurotomaria.

In the midst of certain red sandstones and green shales the following is reported: 5

.1. Avicula. ,

And in a white limestone in the same series an undeterminable species 

of shell is reported as completely filling the rocks. 6

Lul>ec lead mines. From similar rocks in the vicinity of the Lubec 

lead mines, on a little bay north of the productive veins, are: 7

1. Orthis.

2. Spirifera.

3. Ortboceras.

4. Calymene blumenbachii.

Dmis Point. At Davis Point, 7 and in Perry, running up Little 

River, are:

1. Lingula.

2. Modiolopsis.

1 Sixth Ann. Kept. Secretary Board of Agriculture, 1801, Augusta, 1861 (publisher! 1802). 

2 0p. cit., pp. 140-328. <> Op. cit., p. 246. 

3 0p. cit, Augusta, 1801, p.2H2. «Op. cit,p.247. 

4 Op. cit., p. 235. 'Op. cit., p. 237.
WILLIAMS.] THE PEMBROKE FAUNA. 29

Pembroke. At Pembroke 1 fossils are reported "at the extreme 

south point of the town, near S. Mahar's house" and "in the east part 

of Pembroke, on Harden Clark's farm," in "slates, grits, and sandstones of various colors, texture, and degrees of inclination." The 

locality -was discovered by W. B. .Rogers, and some of the species 

were identified by him. The following were determined by E. Billings:

1. Stenopoi'a.

2. Favosites.

3. Petraia.

4. Strophomena.

5. Chonetes.

6. Orthis.

7. JRhynchonella.

8. Spirifera.

9. Eetzia.

10. Athyris. 

11. Atrypa.

The species determined are:

1. Favosites cervicornis.

2. Strophomena rhomboidalis.

3. Chonetes nova-scotica.

4. Rhynchonella "wilsoni var.

5. Atrypa reticularis.

Billings adds: "The rocks of this locality are Upper Silurian and 

belong to the Lower Helderberg series of the New York survey. They 

are nearly on the same horizon with those of Square Lake, and also 

with the upper part of the Arisaig series of Dr. Dawson in Nova 

Scotia."

The following species are added on the determination of Prof. W. B. 

Rogers:

12. Modiolopsis.

13. Avicula.

14. Cyrtodonta.

15. Murchisonia.

16. Pleurotomaria.

17. Platyostoma.

18.' Orthoceras.

19. Calymene.

20. Homalonotus.

21. Tentaculites.

6. Orthis inusculosa(?)

7. Avicula naviformis.

8. Calymene blumenbachii.

9. Homalonotus dawsoni.

15. Spirifer sulcatus.

16. Leptsena rugosa.

17. Orthis elegantnla.

18. Modiolopsis ovatus.

10. Discina tenuilamellata.

11. Cornulites flexuosus.

12. Tentaculites distaus.

13. Avicula lioneymani (?)

14. Beyrichia lata.

Hitchcock mentions 2 " seven other patches of the Lower Helderberg 

group, mostly limestones," which are identified by containing " the 

same coral," which is 

1. Favosites gothlandica.

The seven localities are as follows: (1) "Squaw Mountain at the 

southwest end of Moosehead Lake;" (2) "on an island at the lower 

end of Ripogenus Lake;" (3) "Horseshoe Pond in No. 5, R. 8;" (4) 

"in No. 7, R. 7, near the mouth of the Seboois River," and (5) in No. 

7, R. 6, east of the Seboois River; (6) Ashland, three localities, one of

1 Sixth Ann. Kept. Secretary Board of Agriculture, Augusta, 1801, p. 238. 2 Op. cit., p. 239.
30 CONTRIBUTIONS TO THE GEOLOGY OF MAINE. [BULL, 165.

which is "opposite the hotel," and (7) "on the thoroughfare between 

Portage and Long lakes, and on the west side of Square Lake," the 

numbers indicating their order as reported by Mr. Packard.

Pa/rlin Pond and Moosehead Lake. The following fossils from Parlin Pond and Moosehead Lake, in a tough argillaceous sandstone, were 

identified by Billings. 1

The 2'enera named are:

1. Stropbomena.

2. Chonetes.

3. Orthis.

4. Rhynchonella.

5. Rensselseria.

6. Leptocoelia.

7. Spirifera.

8. Modiolopsis.

9. Cyrtpdonta.

10. Avicula.

11. Murchisonia.

12. Platyostoma.

13. Orthoceras.

4. Kenssekeria ovoides.

5. Leptocoelia flabellites.

6. Spirifera arrecta (or closely allied).

7. Spirifera pyxidata (or closely allied.)''

The species are as follows:

1. Strophornena magnifica (or closely 

allied).

2. Orthis musculosa.

3. Khynchonella oblata (or closely 

allied).

Hitchcock reports large collections of the fossils of the same sandstone from Lake Telos, Webster Lake, and other localities.

On the map accompanying his report Hitchcock has indicated a 

patch of the Oriskany running obliquely from below Paiiin Pond to 

north of the Aroostook River and the more southerly bend of the 

Machias River, on No. 10, R. 7.

The Parlin Pond fauna has the following species identified in later 

publications, 3 on the authority of C. H. Hitchcock:

11. Dalrnanites epicrates.

12. Leptodornus mainensis Bill.

8. Platyostoma ventricosa Con.

9. Streptorhynchus radiata.

10. Fucoides cauda-galli.

Seloois Rwer to Presque Isle. From sundry rocks (sandstones and 

slates) from other localities in northern Maine, " on the Seboois River," 

thence to "Aroostook River near Presque Isle," "near Ashland," 

about the "Eagle Lakes," of which the exact'locality is not given, 

the following species were obtained and identified by Billings: *

1. Strophomena rhomboidalis. 3. Platyostoma.

2. Kensselseria ovides. 4. Dalmanites n. sp.

Among the fossils from the sandstone at Webster Lake was identified:

1. Dalmanites sp.5

1 Sixth Ann. Kept. Secretary Board of Agriculture, Augusta, 1861, p. 244.

2 This same list is repeated in"the report for 1862, p. 286.

3 See Hitchcock, Am. Assoc. Adv. Sci., 1885 and 1873.

4 Sixth Ann. Kept. Secretary Board of Agriculture, p. 245 

& Op. cit., 224.
WILLIAMS.] PERBY AND SQUAEE LAKE FAUNAS. 31

Perry. The red sandstones of Perry and vicinity 1 contain a rich 

flora, which has been described more fully elsewhere, but in the present report a list of eleven species is given on the authority of Dawson. 2

1. Sternbergia = ? Dadoxylon onangondianum Daw.

2. "Aporoxylon sp.

3. Lepidodendron gaspianum Daw.

4. Lepidostrobus richardsoni Daw.

5. Lepidostrobus n. sp.

6. Megaphyton sp.

7. Psilophyton princeps Daw.

8. Leptophlceuni rhombicurn Daw. 3

9. Cyclopteris jacksoni Daw;.

10. Cyclopteris browniana Daw. 4

11. Sphenopteris hitchcocki Daw. 5

The age of this flora is determined as Devonian by the author of 

the species. -The fossil plants were from layers of gray sandstone 

embedded in the red rocks, which is separated unconformably from 

lower "Silurian" rocks. The "bedded trap" is said to "spread over 

the Silurian rocks just as'alluvium is spread over the solid rocks" in 

an exposure southeast of Perry.

Square Lake. The fossils of the Square Lake fauna, as then identified by Billings, are as follows: 6

1. Favosites gothlandica.

2. Zaphrentis n. s.

3. Crinoids, 3 or 4 species.

4. Strophomena, new species like S. punctulifera.

5. Strophomena rhomboidalis (S. rugosa

Hall). 

0. Strophomena, a new species.

7. Rhynchonella wilsoni (var.).

8. Khynchonella n. sp.

9. Rhynchonella n. sp., like R. acutiplicata.

10. Spirifera perlamellosa.

11. Atrypa reticularis.

12. Athyris bella (Navista beltn Hall) 

[sic].

13. Platyostoma subangulata. 

-14. Proetus n. sp. 

15. Bronteus n. sp.

Other rocks are mentioned by Hitchcock as probably of the same 

age, but no fossils are named, and hence decisive evidence is lacking. 

The presence of the Lower Helderberg rocks at the base of Squaw 

Mountain and at Ripogenus Falls is- given on the authority of Mr. 

Hodge, an assistant of Dr. Jackson. 7

The Oriskany fauna was recognized by Jackson and W. B. Rogers 

in several localities previous to Hitchcock's report, but no careful 

determination of the fossils was made by them.

The fossils of the Square Lake limestone were finally described by 

Billings in the Proceedings of the Portland Society in 1869. 8 The

1 Sixth Ann. Kept. Secretary Board of Agriculture, p. 247. <> Op. cit., p. 251, fig. 6.

2 Op. cit., p. 248. «Op. cit., p. 240. j3 Op. cit., p. 249, figs. 3 and 4. 1 Op. cit., pp. 378-379.

 i Op. cit, p. 250, fig. 5.

8 Descriptions of some new species of fossils, with remarks on others already known, from the Silurian and Devonian rocks of Maine: Proc. Portland Soc. Nat. Hist., Vol. I, Pt. II, pp. 104-1'25, and 

plate with 28 woodcut figures of fossils. Portland, 1869.
32 CONTRIBUTIONS TO THE GEOLOGY OF MAINE. [BULL. 165.

date of the article is "Montreal, January 12, 1863." The catalogue 

of the fossils from Square Lake, described by Billings, is as follows: 1

1. Favosites gothlandica Lam.

2. Zaphrentis cf. Z. prolifica.

3. Diphyphyllum.

4. Crinoid, with rnoniliforrn column.

5. Crinoid, with smooth, round column.

6. Fenestella.

7. Incrusting Bryozoan on Orthoceras.

8. Strophomena rhomboidalis Wahlen- 

	berg.

9. Strophomena punctulifera Con.

10. Strophomena indenta Con.

11. Strophomena perplana Con.

12. Orthis cf. 0. discus Hall.

13. Orthis sp. "a larger species" or 

	nearly the same form.

14. Streptorhynchus ?

15. Rhynchonella mainensis n. sp. 2

16. Rhynchonella nucleolata Hall.

17. Rhynchonella aspasia n. sp. 3

18. Rhynchonella cf. bialveata Hall.

19. Rensselteria portlandica n. sp. 1

20. Eatonia medialis Hall.

Billings observes 17 that the aspect of the collection is that of the 

Lower Helderberg, but there are many new species, " and as it is not 

quite clear that this fauna can be exactly paralleled with the Lower 

Helderberg (although it must certainly be very nearly related) it is 

best to call it Upper Silurian for the present."

Species No. 30 of the above list is the same as that referred to Spirifer perla/mellosa in the Maine report (see p. 31, No. 10), and the 

author proposed the name 8. hesione for it, but refers it provisionally 

to S. raricosta Con. Athyris ttancha. No. 27 of this list, is cited as 

A. ~bella in the Hitchcock report of 1861 (see p. 31, No. 12).

Under the name StropJiomena 'punctulifera Con., Billings includes 

 the forms figured as 8. punctulifera, 8. headleycma, and S. cavumbona. 

Under the name Strophomena peiyylana Con., Billings intends to include 

8.pluristriata Con., S. planulata, S. crenistria, and S. fragilis Hall; 

and under the genus Retzia King are included Trematospira and 

Rhynchospira.

21. Leptocoelia n. sp.

22. Retzia maria n. sp. 5

23. Retzia hippolyte n. sp. 6

24. Retzia dubia n. sp. 7

25. Retzia electra n. spt 5

26. Atrypa reticularis Linn.

27. Athyris blancha n. sp.9

28. Athyris harpalyce n.sp. 10

29. Spirifera rnacropleura Con.

30. Spirifera raricosta Con.,S. Hesione? 

	Bill.11

31. Platyceras) both allied to P. subangu32. Platyceras/ lata.

33. Loxonema fitchi? Hall.

34. Orthoceras rigidum Hall.

35. Dalmanites epicrates n. sp.

36. Phacops trajanus n.sp. 12

37. Proetus macrobius n. sp. 13

38. Proetus junius n. sp. u

39. Bronteus pompilius n. sp. 15

40. Lichas.? 16

iProc. Portland Soc. Nat. Hist., Vol. I, Pt. II, pp. 104-105. 

2 Op. cit., p. 110, fig. 4. sOp. cit., p. 114, fig. 11. 

3 Op. cit, p. 111. 9Op. cit., p. 115, fig. 13. 

«Op. cit., p. 115, fig. 12. w Op. cit., p. 116, fig. 14. 

6Op. cit., p. 112, fig. 8. " Op. cit., p. 117, fig. 17. 

"Op. cit., p. 112, fig. 9. 12Op.cit., p. 124, fig. 26. 

'Op. cit., p. 113, fig. 10.

is Op. cit., p. 123, fig. 24. 

"Op. cit., p. 122, fig. 25. 

is Op. cit, p. 123, fig. 25. 

i«0p. cit, p. 125, fig. 28 

"Op. cit., p. 105.
WILLIAMS.] BAILEY AND M INNES EEPOET. 33

In a still later report, by Bailey and Mclnnes, 1 the following addi 

tional species of this fauna are reported:

1. Pholidops ovata? Hall.

2. Orthis eminens? Hall. (This may be 

No. 13 of Billings's list.)

3. Orthis strophomenoides Hall.

4. Streptorhynchus perplanuin ? Con. 

(Probably No. 14of Billings's list.)

5. Spirifera perlamellosa Hall. (Cf. No. 

30 of Billings's list; this is the species 

cited - in the preliminary list given 

by Hitchcock in 1861.)

6. Spirifera niodesta ? Hall.

7. Spirifera sp. ?

8. Meristella Isevis Van.

9. Retzia formosa Hall sp.

10. Rhynchonella allied to R. aspasia B. 

and R. altiplicata Hall.

11. Pterinea sp.

12. Platyceras ventricosum Con. (This 

genus was reported by Billings under two numbers, Nos. 31 and 32.)

13. Platyceras tenuiliratum Hall.

14. Platyceras dilatatum Hall.

15. Platyceras retrorsum Hall.

16. Platyceras curvirostrum Hall.

17. Proetus n. sp. a

18. Lichas billingsi n. sp. 2

19. Leperditia sp.

Billings described, in the former report, several species from other 

localities and gave lists of the following faunas: 

Masardis, Aroostook County* The Masardis fauna is as follows:

1. Crinoids.

2. Orthis n. sp.

3. Strophomena rhomboidalis.

4. Spirifera nympha n. sp. 4

5. Atrypa reticularis.

6. Cheirurus tarquinius n. sp. 5

The author considered this fauna to be equivalent to that of Square 

Lake. No. 6, Cheirurus tarquinius, is reported as being found also in 

the fauna of Port Daniel, Bay of Chaleur.

Tdos Lake. From Telos Lake the following species are reported by 

Billings: 6

6. Platyostoma ventricosa ? Con.

7. Ortboceras cf. 0. rigidum, but more 

coarsely striated.

8. Dalrnanites sp.

9. Avicula or Pterinea.

1. Crinoid, arms of a large.

2. Chonetes?

3. Rhynchonella or Retzia. .

4. Rensselteria ovalis Hall, or a closely 

allied species.

5. Leptodoraus mainensis n. sp. 7

These are interpreted as "most probably from the base of the 

Devonian near the Oriskany sandstone." 0

From the west end of Telos Lake the following are reported:

1. Strophomena rhomboidalis.

2. Streptorhynchus radiata Van.

3. RensselfEria ovalis Hall.

4. Spirifera sp.

This fauna is referred to the same age as the last mentioned.

1 Report on explorations and surveys in portions of northern New Brunswick, and adjacent areas 

in Quebec, and in Maine, United States, by L. W. Bailey and Win. Mclunes: Ann. Kept. Geol. Nat. 

Hist. Survey Canada, 1887, Vol. Ill, Ft. M, pp. lm-52m, and map No. 290.

2 Op. cit., p. 41m. 6 Op. cit., p. 121, fig. 22.

s Proc. Portland Soc. Nat. Hist., Vol. I, Pt. II, p. 106. «Op. cit., p. 106.

* Op. cit., p. 116, fig. 15. ' Op. cit., p. 118, fig. 19.

Bull. 165 3
34 CONTRIBUTIONS TO THE GEOLOGY OF MAINE. [BULL, 165. 

COBSCOOK BAY SERIES.

Professor Shaler 1 has described an interesting series of Silurian 

deposits on the extreme southeastern coast of Maine, which contain 

faunas similar to those of the Ashland and Sheridan series of Aroostook 

County. The deposits resemble these series also in their association 

with detrital ash beds, lavas, and dikes, indicating disturbances of 

igneous origin during the Eosilurian period. Four distinct fossilbearing horizons with their faunas are reported, as follows:

Orange or Whiting Bay. On the west side of Orange or Whiting 

Bay, about half a mile south of Balls Mills, in a very dense, muchjointed, siliceous limestone is contained the following fauna, which is 

correlated by the author with the Lower Helderberg;

18. RhynchoneHa mutabilis.

19. Rhynchoneila abrupta.

20. Khynchonella vellicata var.

21.> Rhynchoneila formosa.

22. Rhychonella sequivalis var.

23. Rensselseria allied to R. ovalis 

(doubful).

24. Leptocoelia allied to L. fimbriata.

25. Leptocoelia allied to L. concava.

26. Atrypa reticularis (extremely abundant) .

27. Orthis pedunculosa var.

28. Orthis planoconvexa var.

29. Strophodonta planulata var.

30. Strophodonta beckii var.

31. Trematospira allied to T. deweyi.

1. Orthoceras perstriatum.

2. Orthoceras tenui-annulatum.

3. Holopea antiqua var.

4. Platystoma depressum.

5. Platyceras lamellosum?

6. Platyceras platystornum var.

7. Loxonema allied to L. fitchii.

8. Anatina sinuata?

9. Avicula allied to A. manticula.

10. Avicula allied to A. securiformis.

11. Avicula allied to A. coinmunis.

12. Megambonia allied to M. lata.

13. Megambonia allied to M. ovata.

14. Spirifer modestus?

15. Spirifer perlamelosus.

16. Spirifer cyclopterus? 

17. Spirifer octocostatus.

Dents Pomt. At the head of Leightoris Cove, about 2 miles to the 

northwest of Dents Point, in shales, generally thin bedded and containing but little lime, the following, which represent the Clinton and 

Niagara fauna in New York, are reported:

1. Dalmanites limulurus. Clinton.

2. Beyrichia symmetrica. Niagara.

3. Orthoceras imbricatum.

4. Orthis allied to 0. elegantula. 1 As usual, these two forms blend together.

5. Orthis allied to 0. hybrida. J Niagara.

6. Atrypa cuneata var. Niagara.

7. Chonetes allied to C. cornuta, but much larger and with finer ridges. Clinton.

8. Orbicula squarniforrnis var. Niagara.

9. Lingula oblata. Clinton.

10. Avicula allied to A. textilis. Lower Helderberg.

11. Avicula emacerata. Niagara.

12. Avicula rhomboidea. Clinton.

13. Modiolopsis sublatus. Niagara.

1 Preliminary report on the geology of the Cobscook Bay district, Maine: Am. Jour. Sci., 3d series, 

Vol. XX-XII, July, 1886, pp. 35-60.
WILLIAMS.] COBSCOOK AND NOBTH HAVEN FAUNAS. 35

14. Modiolopsis ovatus var. Clinton.

15. Orthonota curta var. Clinton.

16. Cyclonema ventricosa. Clinton.

17. Murchisonia subulata.

Dennysmlle. About 1 mile north of Dennysville the following are 

reported, and referred to the horizon of the Lockport ("Niagara") 

limestone:

4. Spirifer crispus. i Not distinctly sepa5. Spirifer bilobus. / rable. Niagara.

6. Syringopora multioaulus? Niagara.

7. Heliolites spiriipora. Niagara.

1. Pleurotomaria percarinata var. Trenton.

2. Atrypa nitida var. Niagara.

3. Atrypa aprinis var. Niagara.

Moose Island. In black and dark-gray shales and slates, on the 

western shore of Moose Island, from north of Shackford Point to 

near Eastport, the following faunas, probably belonging to the horizon 

of the Ohio shale (Devonian), are reported:

1. Modiomorpha allied to M. subulata.

2. Modiomorpha sp. undetermined.

3. Murchisonia desiderata ?

4. JBayrichia, species not determined.

5. Lingula, a species not determined.

6. Discina, two species.

NORTH HAVEN SEEIES OF PENOBSCOT BAY.

A characteristic Eosilurian fauna has been reported by Messrs. W. W. 

Dodge and Charles E. Beecher from the island of North Haven. 1 The 

rocks in which the fossils occur are described as dark bluish-gray, 

indurated shales, slightly calcareous at places, sometimes with calcareous nodules; red shale with nodules of white limestone; conglomerate sandstones, with dikes, porphyrite, and ash beds associated. 

The list of species was prepared by C. E. Beecher, who described the 

majority of the specimens as "too fragmentary and poorly preserved 

for accurate description or determination." The list given is as follows, 

the letters indicating separate localities, which are indicated on a map 

in the original article: 8

1. Monograptus clintonensis Hall, g.

2. Coenostromasp., c.

3. Streptelasma calyculum Hall, g, c.

4. Chonophyllum niagarense Hall, d.

5. Favosites venustus Hall, c.

6. Favosites niagarensis Hall, c.

i On the occurrence of Upper Silurian strata near Penobscot Bay, Maine, by William W. Dodge and 

Charles E. Beecher: Am. Jour. Sci., 3d series, Vol. XLIII, 1892, pp. 412-418.

- The letters indicate the successive strata, described by the authors on pages 414 and 415 of the article 

cited, as follows:

Feet. 

i and j. Sundry argillaceous and calcareous beds above the red shale............................. 175

h. Red shale, J7and L7of the author's map....................................................... 42

g. Dark indurated shale, J and L8-13 of the author's map.......................................... 203

f. Light-colored porphyry, J14 and L14 of the author's map....................................... 3

e. Concealed ............................................................................ ........... 75

d. Brown impure limestone, J17, L17, and probably 0 of the author's map ...'... ................ 21

c. Conglomerate, L22-19, and coarse calcareous sandstone, J18 of the author's map ........ ..... 16

b. Concealed............................................................................ .......... 59

a. Conglomerate, J19 of the author's map...................................................... ... 12

Total. 606
CONTEIBUTIONS TO THE GEOLOGY OF MAINE.

7. Favosites favosus Hall, c.

8. Cladopora sp., d.

9. Coenites ramulosus Hall, d.

10. Monticulipora sp., i.

11. Halysites catenulatus Linn6, c.

12. Heliolites spinoporus Hall, c.

13. Crinoid fragments, i, ], g.

14. Cornulites sp., j.

15. Tentaculites sp., j.

16. Encrinurus punctatus Wahl., g, d.

17. Calymene niagarensis Hall, L

18. Dalmanites limulurus Green, i, g.

19. Ceraurus niagarensis Hall, i.

20. Illaenus ioxus Hall, g.

21. Proetus stokesi Hall, i.

22. Beyrichia, 2 species, i.

23. Leperditia sp., i.

24. Fenestella sp., i. (In limestone nod- 

' ule.)

25. Stictopora sp., i.

26. Lingula lamellosa Hall, g.

27. Schizocrania sp., i.

28. Orthis elegantula Dal., i, j, g.

29. Orthis hybrida Sow., i.

30. Orthis, 2 species, g, d.

31. Leptsena transversalis Wahl., g, d.

32. Leptsena (cf.) sericeaSow., i, j.

33. Strophomena rhomboidalis Wile., g.

34. Stropheodonta profunda Hall, j.

35. StreptorhynchussubplanumCon., i.

36. Chonetes cornutus Hall, i.

37. Pentamerus occidentalis Hall, c.

38. Meristina nitida Hall, i.

- In a later paper 1 this list is supplemented by the addition of the following species reported by Mr. Beecher, viz:

71. Cyathophyllum sp.

72. Syringopora sp.

73. Ichthyocrinus leevis.

74. Eucalyptocrinus coelatus.

39. Meristina sp.,i.

40. Nucleospira pisum Hall, d.

41. Coelospira disparilis Hall, g.

42. Spirifer crispus His., i, j, d.

43. Spirifer sulcatus His., i.

44. Spirifer radiatus Sow., g.

45. Cyrtina pyramidalis Hall, i.

46. Atrypa reticularis Linns', i, j, g.

47. Atrypa nodostriata Hall, d.

48. Rhynchonella neglecta Hall, i, j.

49. Rhynchonella obtusiplicata Hall, i.

50. Rhynchonella; sp., i.

51. Rhynchonella (Wilsonia) sp., i, j.

52. Nucula sp., i.

53. Tellinomya sp., j.

54. Avicula demissa Con., i.

55. ?Avicula subplana Hall, g.

56. Avicula sp., i.

57. Cypricardinia sp., d.

58. Platyostoma niagarense Hall, g.

59. Loxonemasp., i, g.

60. Pleurotomaria sp., i, g.

61. Bellerophon sp., i, g.

62. Cyrtolites sp., g.

63. Murchisonia sp., g.

64. Hyolithes sp., j.

65. Orthoceras annulatum Sow., i, g.

66. Orthoceras subcancellatum Hall, g.

67. Orthoceras virgulatum Hall, g.

68. Orthoceras (annulated), 2 species, g.

69. Gomphoceras sp., g.

70. Cytoceras subcancellatum Hall, g.

75. Homalonatus delphijiacephalus Gr.

76. Proetus sp.

77. Oncoceras sp.

78. Coenostroma sp.

Adding the second species recorded under the numbers 22, 30, and 

68, and deducting 13 as not a recognized species, the total reaches 80 

species for this list.

Concerning the correlation of this fauna the author says that, '' It 

seems justifiable to consider the fossiliferous rock at North Haven as 

representing a faunal equivalent to the Clinton and Niagara, with a 

decidedly strong Niagara facies. Therefore, the broader term Niagara 

will more correctly express the chronological relations of these strata." 2

1 The Geology of the Fox Islands, Maine; a Contribution to the Study of Old Volcanoes, by George 

Otis Smith ^published by the author, Skowhegan, Maine, 1896), pp. 22-23. 

s Am. Jour.ScL, 3d series, Vol.XLUI,p.417.
WILLIAMS.] FAUNAS OF CANADIAN LOCALITIES. 37 

LOCALITIES IN CANADA. »

Campbell Rivw, Victoria, New Brunswick. In the Annual Report 

for 1886,' Bailey and Mclnnes, of the Canadian survey, report a small 

area of. rocks with an Oriskany fauna about 35 miles east and a few 

miles north of Grand Falls, on the St. Johns River. The rocks are 

"soft, dark blue, calcareous slates, and soft, dark gray, rusty buff 

weathering sandstones," and are reported as surrounded by preCambrian and Cambrian rock. The following fossils are identified by 

Dr. Ami 2 :

1. Carbonized stem of plant.

2. Polypora (?) ?

3. Strophomena (Strophodonta) magnifica Hall.

4. Strophomena (Strophodonta) varistriata (?) Conrad.

5. Strophomena rhomboidalis Wile.

6. Orthis hipparionyx Van.

7. Orthis (cf. 0. oblata N (H.)

8. Leptocoelia flabellites Con.

9. Eatonia(?)

10. Spirifera arrecta Hall..

11. Spirifera (cf. S. submucronata and S. cycloptera).

12. ? Pterinea textilis H.

13. Pterinea, or Megam'bonia.

14. ? Calymene.

St. Helens Island (near Montreal), Canada. Mr. William Deeks, in 

the Canadian Record of Science, 3 has made a careful review of all the 

material accumulated at McGill College, and publishes the following 

'ist of species known to occur in the limestones of St. Helens Island:

1. Crinoid stems. .

2. Stenopora.

3. Chsetetes abruptus. -

4. Callopora incrassata.

5. Favosites helderbergise.

6. Favosites sp. ?

7. Zaphrentis corticata.

8. Zaphrentis roemeri.

9. Zaphrentis sp. ?

10. Heliolites.

11. Fenestella cf.peranguMa.

12. Ptilodictya acuta.

13. Atrypa reticularis.

14. Chonetes sp. ?

15. Leptoena sp. ?

16. Lingula perlata.

17. Orthis deformis.

18. Orthis discus.

19. Orthis eminens.

20. Orthis hipparionyx.

21. Orthis oblata.

22. Orthis tubulostriata.

23. Pentamerus galeatus.

24. Pentamerus pseudogaleatus.

25. Pentamerus verneuilli.

26. Rhynchonella sequivalvis.

27. Rhynchonella formosa.

28. Rhynchonella mutabilis.

29. Rhynchonella, cf. mutabilis.

30. Rhynchonella nucleolata.

31. Rhynchonella vellicata.

32. Rhynchonella ventricosa.

33. Spirifer cf. S. arenosa.

34.. Spirifer concinnus.

1 Geol. Nat. Hist. Survey Canada, Report on Explorations In Portions of the Counties of Victoria, 

Northumberland, and Restigouche, New Brunswick, to accompany quarter-sheet map 2 N. W., by 

L. W. Bailey and W. Mclnnes, pp. ln-19», Montreal, 1887.

2 Op. cit.,p.8».

8 The Lower Helderberg formation of St. Helens Island: Canadian Rec. Sci., Vol. IV, No. 2, pp. 104.^ 

109, Montreal, 1890.
38 - CONTRIBUTIONS TO THE GEOLOGY OF MAINE. [BULL. 165.

35. Spirifer cyclopterus.

36. Stricklandinia gaspensis.

37. Streptorhynchus radiata.

38. Strophodonta profunda.

39. Strophodonta punctulifera.

41. Strophomena rhomboidalis.

42. Avicula sp. ?

43. Platyostoma depressa.

44. Tentaculites helena (in loose fragments) .

40. Strophodonta varistriata.

The author states that the following, "from their abundance, may 

be called the most characteristic fossils of the deposit: "Atrypa reticularis, Pentameruspseudogaleatus, Rhynchonellaformma, Rhynchonella 

nucleolata, Spirifer coiicinnus, /Spirifer cyclopterus, Strophodonta varistriata, and /Strophodontapunctulifera." 1

Another list of the same specimens, determined by Dr. Ami, of the 

Canadian survey, is published in the Annual Report for 1894. 2 Besides 

numerous fragments of crinoidal columns, the following are found:

1. Favosites cf. F. gothlandicus Lam. .

2. Favosites cf. helderbergise Hall..

3. Favosites sp. ?

4. Pachypora sp. 2.

5. Zaphrentis sp. 1.

6. Zaphrentis sp. 2.

7. Cyathophylloid coral sp. ?

8. Callopora or Calloporella.

9. Polypora cf. P. perangulata Hall.

10. Fenestella sp. ?

11. Ptilodictya sp. ? .

12. Chonetes cf. melonica.

13. Orthis cf. 0. Rhipidomella eminens Hall.

14. Orthis (Rhipidomella) oblata Hall.

15. Orthis cf. (Orthostrophia) strophomenoides Hall.

16. Strophonella- punctulifera Conrad.

17. Strophonella cavumbona Hall.

18. Strophodonta varistriata Con. "Tendency toward var. arata."

19. Strophodonta varistriata Conrad, ".var. more arcuate than type."

20. ? Strophodonta becki Hall, or Streptorhynchus woolworthanum HalL

21. Leptagonia rhomboidalis Wile.

22. ? cf. Streptorhynchus radiatum Van.

23. Spirifera concinna Hall. .

24. Spirifera concinna (large var.) *

25. Spirifera cf. S. cumberlandise Hall.

26. Spirifera n. sp. ? s

26." Spirifera "of the type of S. arenosa Con."

27. Spirifera cycloptera Hall.

28. Spirifera "sp. with from eighteen to twenty costse on each side of tlie mesial 

sinus. General appearance very much like S. pennata (= S. mucronata), not quite so arcuate and the concentric lines of growth are 

not so strongly lamellose or rugose."

1 Canadian Rec. Sci., Vol. IV, No. 2, p. 108.

2 Preliminary lists of organic remains occurring in various geological formations comprised in the 

southwest quarter-sheet map of the eastern townships of the Province of Quebec, by Henry M. Ami: 

Ann. Kept. Qeol. Survey Canada, Vol. VII, new series, p. 155J, Ottawa, 1896.
WILLIAMS.] ST. HELENS ISLAND FAUNA. 39

29. Spirifera cf. S. perlamellosa Hall.

30. Atrypa reticularis Linn.

31. Trematospira multistriataliall, "or closely related species."

32. ? Leiorhynchus sp. ?

33. Rhynchonella abrupta Hall.

34. Rhynchonella cf. R. acutiplicata Hall.

35. Rhynchonella ? sequivalvis Hall, "possibly a Rensselseria."

36. Rhynchonella formosa Hall.

37. Rhynchonella nucleolata Hall.

38. Rhynchonella nobilis Hall. Also cf. R. campbellana Hall.

39. Rhynchonella pleiopleura, or multistriata of Hall.

40. Rhynchonella ventricosa Hall.

41. Eatonia sinuata Hall, or a closely related species.

42. Pentamerus galeatus Dalman.

43. Pentamerus pseudogaleatusHall.

44. Pterinea sp., cf. P. textilis Hall. A small variety.

45. Platyostoma depressum Hall.

GASP6 SERIES.

The Gasp6 limestones and sandstones are described at length in the 

report of the Geological Survey of Canada. 1 There is at the base a 

series of limestones, 2,010 feet thick, divided into eight divisions, 

numbered from the bottom upward 1 to 8. Comformably succeeding 

the limestones follow 7,036 feet of sandstones, numbered from below 

upward as 1 to 8 successive formations.

The fossils from this series were described by E. Billings in the 

report of the Geological Survey of Canada on "Paleozoic Fossils. 1 ' 2 

The following localities and formations furnished the fossils described:

	Locality. Formation. 

A. Indian Cove, Gasp6 .................... .Gasp<§ limestone, No. 8.

B. Cape Gaspe"............................. Gaspe" limestone, No. 1.

C. Split Rock, Perc<§........................Lower Devonian.

D. Mount Joli, near Perc6 ................. .Gasp6 limestone, No. 8.

E. Between Cape Gaspe" and Cape Rosier.... .Gasp6 limestone, No. 1.

F. Grand Greve, Gaspe" Bay.................Gasp6 limestone, No. 8.

G. Cape Bon Ami, Gasp6 .................. .Gasp6 limestone, No. 5, passage beds.

H. Little Gasp6 ............................. Gasp6 limestone, No. 8.

I. Perc6, Bay of Chaleurs .................. Lower Devonian.

J. Gaspe" ..................................Gasp6 sandstone.

K. Gasp6 .................................. Limestone.

L. York River, Gasp6 ......................Devonian.

M. Head of the falls of Dartmouth River .... .Gasp6 sandstone.

1 Geol. Survey Canada, Report of Progress, 1803, pp. 390-404.

2 Paleozoic Fossils, Vol. II, Pt. I. 1. On some of the fossils of the (iuspe series of rocks, PI. I IX, 

figs. 1-31, pp. 1-64, Montreal, 1874.
40 CONTRIBUTIONS TO THE GEOLOGY OF MAINE. [BULL. 165.

The species reported and the new species described are given in the 

following list, with the lottery indicating localities as above:

Rhynchonella excel lens n.sp A. 

Rhynchonella dryope n. sp. F. 

Rhynchonella pleiopleura

Con..................... A.

Eatonia peculiaris Con ..... A.

Pentamerus galeatus Dal.... E.

Rensselseria ovoides Eaton A. I. C. J. 

Leptoccelia flabellites Con

............. Gaspe" No. 8 K. J. I.

Spirifera gaspensis n. sp.. -. J. C. 

Spirifera superba n. sp ..... A.

Spirifera raricosta Con...... F.

Spirifera cycloptera Hall ... F. A. C. 

Cyrtina affinis n. sp........ F.

Sanguinolites tethys n. sp... F. 

Goniophora mediocris n. sp. A. 

Grammysia canadensis n. sp J. 

Modioniorpha inornata n. sp L. 

Mytilarca canadensis n. sp. No. 8, K. 

Mytilarca nitida n. sp...... x A.

Leptodomus canadensis n.sp A. 

Anodontopsisventricosa n.sp A. 

Cypricardinia distincta n. sp A. 

Modiolopsis varia n. sp..... E.

Murchisonia hebe n. sp . - -. A. 

Murchisonia egregia n. sp .. M. 

Plourotomariaprincessa n.sp E. 

Platyostoma affinis n. sp. (cf.

P. ventricosa Con) ....... A.

Pleurotomaria voltumna

n.sp .................... F.

Pleurotomaria delia n. sp... F. 

Pleurotomaria lydia n. sp .. A. 

Bollerophon plenus n. sp... A. 

Proetus phocion n.sp...... A.

Arisaig, Nova Scotia. The Arisaig section was correlated with the 

Silurian of Murchison as early as 1864 by D. Honeyman. 1 Zone D 

of Honeyman's classification was defined as equivalent to the Upper 

Ludlow.

1. Zaphrentis incondita n. sp.. 

2. Zaphrentis rugatula n. sp. . . 

3. Zaphrentis corticata n. sp 

4. Zaphrentis -cingulosa n. sp.. 

5. Phillipsastrea affinis n. sp. . . 

6. Polypora ? psyche n.sp.... 

7. Dictyonema splendens n. sp.

9. Lingula lucretian. sp.......

11. Crania bella n.sp ..........

12. Chonetes rnelonica n.sp.... 

13. Chonetes canadensis n.sp.. 

14. Chonetes dawsoni n.sp.... 

15. Chonetes antiopa n. sp .....

17. Strophomena galatea n. sp. . 

18. Strophomena magniventra 

Hall ....................

19. Strophomena inequiradiata

20. Strophomena varistriata Con 

21. Strophomena rhomboidalis 

Wile .............. 1,5, and

22. Strophomena irene n. sp.... 

23. Strophomena blainvillei n.sp 

24. Strophomena tullia n.sp... 

25. Strophomena punctulifera 

Con.....................

26. Strophomena punctulifera 

var .....................

27. Strophomena cf. perplana 

Con.....................

28. Orthis livia Bill ............

29. Orthis aurelia n. sp ........

30. Orthis lucia n. so ..........

A. 

B.

C. 

D. 

A. 

.A. 

E. 

, F. 

G. 

G. 

G. 

H. 

I. 

C.J. 

C.D. 

F.H. 

A.

A.

A. 

E.

8,K. 

F. 

J. 

C.D,

E.

A.F.

K.

A. 

A. 

A.

31. 

32. 

33.

34. 

35. 

36.

37.

38. 

39. 

40. 

41. 

42. 

43. 

44. 

45. 

46. 

47. 

48. 

49. 

50. 

51. 

52. 

53. 

54. 

55. 

56.

57.

58. 

59. 

60. 

61.

1 On the geology of Arisaig, Nova Scotia, by the Rev. D. Honeyman: Quart. Jour. Geol. Soc. London, 

Vol. X.X, 1864, pp. 333-346.
WILLIAMS.] FAUNA OF ZONE D, ARISATG, NOVA SCOTIA. 41

The following list shows the character of the fauna of the group D:

1. Lituites.

2. Phragmoceras.

3. Ormoceras? ,

4. ? long, tapering, and recurved.

5. Orthoceras nummulare Sow.

6. Orthooeras,very like 0. bullatum Sow.

7. Orthoceras ibex Sow.

8. Orthoceras exornatum Dawsbn.

9. Orthoceras punctostriatnm Hall.

10. Orthoceras, 4 sp.

11. Bellerophon trilobatus Sow.

12. Bellerophon carinatus Sow.

13. Bellerophon striatus D'Orb.

14. Bellerophon expansus Sow.

15. Theca Forbesii Sharp.

16. Coleoprion ? sp.

17. Murchisonia Arisaigensis Hall.

18. Murchisonia aciculata Hall.

19. Pleurotomaria.

20. Modiolopsis ? rhomboidea Hall.

21. Modiolopsis subnasuta Hall.

22. Clidophorus cuneatus Hall.

23. Clidophorus concentricus Hall.

24. Clidophorus erectus Hall.

25. Clidophorus elongatus Hall.

26. Clidophorus semiradiatus Hall.

27. Clidophorus nuculifqrmis Hall.

28. Clidophorus subovatus Hall.

29. Avicula Honeymani Hall.

30. Pterinea retroflexa.

31. Orthonota (like many Ludlow species) Salter.

32. Goniophora cymbseformis Sow.

33. Chonetes Nova-Scotica Hall.

34. Chonetes tenuistriata Hall.

35. Orthis, 2 sp.

36. Spirifer subsulcatus Hall.

37. Rhynchonella, 3 sp.

38. Discina rugata Sow.

39. Discina ? lineata.

40. Discina ? tenuilamellata HalJ.

41. Crania Acadiensis" Hall.

42. Lingula sp.

43. Homalonotus Dawsoni Hall.

44. Homalonotus Knightii Konig.

45. Dalmania Logani Hall.

46. Phacops Downingise Salt.

47. Calymene, different from Blumenbachii Brong.

48. Proetus Stokesii ?

49. Beyrichia pustulosa Hall.

50. Beyrichia equilatera Hall.

51. Beyrichia, 2 ep.

52. Leperditia sinuata Hall.

53. Crinoidea.

54. Tentaculites.

55. Cornulites serpularius.

56. Serpulites n. sp. (in clusters on shell 

of Orthoceras).

57. Stenopora.

58. Heliopora fragilis var. Acadiensis 

Hall.

The species in this list followed by the name of Hall were all 

described by Jarnes Hall* from this locality.

Mr. Salter examined this fauna, and "unhesitatingly referred it to 

the Ludlow tilestone." This is the upper member of the Silurian of 

modern classification, and is called the Downtonian.

Dr. Ami has recently made a study of this section, and identified 

the fossils in the Canadian survey office coming from the Arisaig section. His identifications are published in the Proceedings and Transactions of the Nova'Scotian Institute of Science, Halifax, 2d series, 

Vol. I, Pt. I, pp. 185-192. A list of 163 species is given, but the association of these species into separate faunas is not made in the list, and 

they include both Upper and Lower Silurian species. A further study 

of these sections should throw; some light upon the Maine faunas.

o ' Description of new species of fossils from the Silurian rocks of Nova Scotia, by James Hall: Canadian Nat. and Geol., Vol. V, 1800, pp. 141-159.
42 CONTRIBUTIONS TO THE GEOLOGY OF MAINE. [BULL. 166.

SOME ADDITIONAL FAUNAS CLOSEST ALLIED TO MAINE

PALEOZOIC FAUNAS.

Oriskany ofBecraft Mountain, New York. The following list gives 

the preliminary determination of species found in the-Becraft fauna 

and reported by J. M. Clarke. 1

1. Spine of undetermined fish.

2. Spirorbis sp.

3. Autodjetus sp. n.

4. Dalmanites sp. n. A.; cf. D. anchiops, 

D. pleuroptyx.

5. Dalmanites sp. n. A. var.; cf. D. 

micrurus.

6. Dalmanites sp. n. B.; cf. D. dentatus.

7. Dalmanites sp. n. C.

8. Dalmanites sp. ?D.; cf. D. pleuroptyx.

9. Dalmanites phacoptyx. (Up. Held., 

Ontario.)

10. Phacops sp. n.; cf. P. logani.

11. Phacops (Acaste) cf. anceps. (Up. 

Held., Ontario.)

12. Homalonotus sp. (small) ; . cf. A. 

major.

13. Cordania sp. n.; cf. C. cyclurus.

14. Cyphaspis sp. n.; cf. C. coelebs, C. 

minuscula.

15. Proetus sp. n. ? A.; cf.P. angustifronsclarus-Rowi.

16. Proetus sp. n. B.; cf. P. crassimarginatus.

17. Acidaspis tuberculatus.

18. Leperditia sp.

19. Primitia sp. >< 20. Turrilepas sp.

21. Platyceras tortuosum.

22. Platyceras nodosum.

23. Strophostylus expansus.

24. Diaphorostoma ventricosum.

25. Diaphorostoma sp. n.; cf. D. lineatum.

26. Cyrtolites expansus ?

27. Pleurotomaria sp. n.

28. Bellerophon sp. n. ? -

29. Conularia sp. ?

30. Coleolus sp. ?

31. Tentaculites cf. elongatus.

32. Tentaculites sp. n.

33. Actinopteria cf. textilis.

34. Aviculopecten cf. A. schoharie.

35. Megamboiiia bellistriata.

36. Megambonia lamellosa.

37. Goniophora sp. n.

38. Cypricardinia cf. lamellosa.

39. Conocardium sp.

40. Lingula sp.

41. Orbiculoidea sp.

42. Crania sp. n.; cf. C. agaricina.

43. Crania sp. n.

44. Pholidops terminalis=P. arenaria.

45. Pholidops sp. n.; cf. P. squamiformis.

46. Orthis perelegans.

47. Orthis cf. oblata.

48. Orthis sp. ?

49. Orthothetes cf. woolworthana.

50. Orthothetes sp. n.; cf. 0. lens.

51. Hipparionyx proximus.

52. Leptsena rhomboidalis (not var. ventricosa).

53. Stropheodonta lincklaeni.

54. Stropheodonta cf. radiata; cf. S. demissa.

55. Stropheodonta sp. n. A.; cf. Rafinesquina alternata.

56. Stropheodonta sp. n. B.; cf. S. alveata.

57. Leptostrophia magnifica (small).

58. Leptostrophia cf. becki (small and 

abundant).

59. Leptostrophia perplana (but more 

convex).

60. Strophonella cf. headleyana.

61. Vitulina?

62. Chonetes sp. n.

63. Chonostrophia sp. n.

64. Anoplia nucleata.

65. Spirifer arrectus; cf. S. cyclopterus.

66. Spirifer arenosus.

67. Spirifer pyxidatus.

68. Spirifer modestus.

69. Spirifer cf. fimbriatus.

70. Cyrtina rostrata.

71. Cyrtina cf. dalmani.

72. Meristella sp. n.; cf. M. oblata.

73. Meristella cf. leevis.

74. Meristella sp. n.

75. Trematospira multistriata.

i Notice of a new Lower Oriskany fauna in Columbia County, New York, by C. E. Beecher; with 

an annotated list of fossils, by J. M.^Clarke: Am. Jour. Sci., Nov., 1892, 3d series, Vol. XLIV, p. 411.
WILLIAMS.] FAUNAS FROM MISSOURI AND ILLINOIS. 43

76. Coelospira sp. n.; cf. C. Camilla and 

	C. concava.

77. Coelospira sp.; cf. C. concava.

78. Leptocoelia flabellites.

79. Leptocoelia acutiplicata.

80. Anastrophia sp. n.

81. Rensselseria ovoides.

82. RensseUeria suessiana?

83. Rensseleeria ovalis?

84. Rhynchonella oblata.

85. Rhynchonella barrandii.

86. Rhynchonella cf. speciosa.

87. Rhynchonella sp.

88. Eatonia medialis.

89. Eatonia peculiaris.

90. Centronella sp. n.; cf. C. glans-fagea.

91. Cryptonella sp. n.

92. Fenestella celsipora.

93. Fenestella sp.

94. Heirdtrypa cf. columellata.

95. Polypora sp.?

96. Reptaria sp.

97. Hederella sp.

98. Clonopora sp.

99. Fistulipora sp.

100. Zaphrentis cf. roemeri.

101. Zaphrentis sp.?

102. Romingeria sp.

103. Monticulipora.

104. Trachypora sp.

105. Edriocrinus sacculus.

106. Hindiasp.

Baileys Lmdting, Perry County, Missowi. This fauna, referred to 

the "Lower Helderberg group" (Delthyris Shaly limestone) by Meek 

and Worthen, 1 is important in the present discussion, as it exhibits the 

combination of forms in this central area about a thousand miles distant, to the south and west, from the typical New York localities. 

The fossils come from a limestone. The following list of species is 

given by Meek and Worthen:

1. Striatopora rnissouriensis n. sp.

2. Edriocrinus pocilliformis Hall.

3. Orthis hybrida Sowerby? (cf. 0. 

oblata.)

4. Orthis subcarinata Hall.

5. Strophomena (Strophodonta) cavumbona Hall ?

6. Merista Isevis Van ? (sp.). «

7. Zygospira subconcava M. & W.

8. Trematospira ? imbricata Hall.

9. Cyrtina dalmani Hall (sp.).

10. Spirifer perlamellosus Hall.

11. Platyceras subundatum M. & W.

12. Platyceras spirale Hall.

13. Platyceras (Orthonychia) pyrainidaturn Hall ?

14. Acidaspis hamata Con. (sp.).

15. Dalmanites tridentiferus Shumard.

Clear Creek, Union Comity, Illinois. In a cherty limestone.

The following fauna from southern Illinois is described by Meek 

and Worthen, 2 and referred to the Oriskany group by them. The 

species named occur in a cherty limestone, and are as follows:

7. Rensseleeria condoni McChesney (cf. 

ovalis).

8. Stricklandinia elongata var. curta. 

=Amphigenia curta M. & W.

9. Strophostylus ? concellatus M. & W.

10. Platyceras spirale Hall?

1. Leptsena ? nucleata Hall.

2. Rhynchonella speciosa Hall.

3. Eatonia peculiaris Con. (sp.).

4. Leptocoelia flabellites Con. (sp.).

5. Spirifer engelrnanni M. & W. (cf. S. 

arrectus).

6. Spirifer hemicyclus M. & W. (cf. S. 

varicosus).

Jonesboro, Union Comity, Illinois. Meek and Worthen report the 

following species from a light yellowish, friable sandstone outcrop1 Geol. Survey Illinois, Vol. Ill, Geology and Paleontology, Fossils of the Lower Helderberg group 

(Delthyris Shaly limestone), 1868, pp. 368-392. 

2 Geol. Survey Illinois, Vol. Ill, Geology and Paleontology, 1868, pp. 393-406.
44 CONTRIBUTIONS TO THE GEOLOGY OF MAINE. [BULL. 1G5.

ping at Jonesboro, in southern Illinois, and refer the fauna to the 

Corniferous group. 1

1. Pleurodictyum problematicum Goldf. ?

2. Baryphyllum ?? arenarium M. & W.

3. Zaphrentis (sp. undt.).

4. Orthis sp. (cf. 0. musculosa).

5. Strophomena (Strophodonta) sp. ?

6. Strophomena (Strophodonta) sp. ?

7. Productus exantheinatus Hall ??

8. Spirifer perextensus M. & W.

9. Spirifer paradoxus Schlot.?? (sp.).

10. Odontocephalus ?

11. Dalmanites (Odontocephalus) segeria 

Hall?(sp.).

NEW PALEOZOIC FAUNAS FROM AROOSTOOK AND SOMERSET COUNTIES, MAINE. '£ 

The new Paleozoic faunas from these counties include the faunas of 

(1) the Aroostook limestone, (2) the Graptolite shales, (3) the Sheridan 

sandstone, (4) the Ashland shales, (5) the Ashland limestone, (6) the 

Square Lake limestone, (7) the Chapman sandstone, (8) the Moose 

River sandstone, and (9) the Mapleton sandstone.

/ m AROOSTOOK LIMESTONE.

Under the above name are grouped the calcareous shales and slates 

covering a large part of the eastern township of Aroostook County. 

Their petrographic and structural characters are described by Dr. 

Gregory (p. 141, et seq.). The Aroostook River cuts them from Wade 

Township to its junction with the St. John. They were referred to 

the Upper Silurian by Hitchcock, 2 and later writers have not succeeded 

in getting much more definite knowledge of their age.

The few fossils found in them indicate as great age as the Clinton, 

and comparison with neighboring rocks to the west confirms this general estimate. Cleavage has affected them to such an extent that it 

has produced real slaty cleavage occasionally, and in most cases has 

so much disturbed the original structure by cross-cleavage planes as 

to make the original bedding difficult to discover, except where bands 

of limestone appear.

The few fossils obtained are fucoids and trails and markings of 

worms or some other marine animals. Specimens in light-greenish 

shales at Caribou and Presque Isle resemble the forms figured in the 

New York reports as JButhotrephis gracilis from the Clinton shales. 

Traces of Acidaspis are also seen, and in calcareous layers in Presque 

Isle and Mapleton Bilobites Hlobus, an Orthis close to 0. elegcmtula,' 

and Nudeospira pisiformis have been discovered.

These all indicate that the formation was as late as Eosilurian, and 

not as early as Ordovician (Lower Silurian). If this interpretation

1 Geol. Survey Illinois, Vol. Ill, Geology and Paleontology, pp. 407-418. 

8 Sixth Ann. Kept. Secretary Board of Agriculture, Maine, 1861.
WILLIAMS.] THE GBAPTOLITE SHALES OF CHAPMAN. 4 5

be adopted, the terrane may be regarded as older than the-Sheridan 

sandstone and Ashland shale and limestone, and as representing the 

base of the Silurian for this region.

There is little doubt as to its being more recent than the pure, noncalcareous slates, a considerable belt of which cuts across the country 

in a southwesterly direction west of the Aroostook limestone.

GRAPTOLITE SHALES.

In the northern part of Chapman Township Dr. Gregory discovered, 

in 1898, a calcareous sandy shale containing graptolites. The section 

(1099 D) 1 is on the sides of a hill in the western part of Chapman, on 

W. H. Littlefield's farm, on the west side of the Swanback road, and 

about three-fourths mile south of the Mapleton line.

The strata present two planes of fissility, as is frequently the case 

with the shales of all this region.. Judging, however, from the plane 

in which the graptolites lie in the rock, the strike of bedding is about 

N. 35° E., with a dip of about 60° NW. The other plane of fissility 

has a strike of about N. TO0 W., and dips at an angle of 25° SE. With 

this interpretation of the position of the strata, 1099 D 5 on the west 

side of the hill would be the highest stratum; then D 1, which may be 

a continuation of D 5, and below this D 2 and then D 3. 1099 D 3 is a 

, fine-grained brown-gray sandstone, with nodules or lenticles of argil- 

' laceous limestone, which are believed to be the Aroostook limestone. 

This weathers by leaching to a rottenstone, in which condition no bedding is evident. In D 3 graptolites are rare, but Coleolus is frequent. 

Above D 3,150 feet or so, the shales, D 2, are dark gray and little 

} calcareous, or not at all so,- and glisten with mica grains on the fractures, 

the rock splitting along what are believed to be the bedding planes, on 

which lie the fossil graptolites.

Above D 2 is D1, more purely arenaceous than D 2, and fine grained. 

This stratum contains only occasional crinoid stems and fragments of 

corals or some other calcareous fossil.

On the opposite or west side of the hill, still dipping westward, is 

D 5, which closely resembles D1, and which contains crinoid stems and 

traces of Coleolus. The immediate relation to other rocks is not evident, but about a quarter mile to the north of D 3, on lot 9 of Chapman 

Township, occurs a limestone striking N. 30° E. and standing nearly 

vertical. At that exposure the limestone abuts against a sandstone 

similar to the one farther south, and it is probable that the sandstones 

are stratigraphically older than the limestone. The fossils of this limestone enable us clearly to identify its age as Eosilurian. The fauna is 

that of the Ashland limestone.

i The numbers here and below refer to the rock exposures, the locations of which are given in Pt. 

m of this bulletin.
46 CONTE1BUTIONS TO THE GEOLOGY OF MAINE. [BULL. 165.

The semislaty structure of the shaly sandstones also is evidence that 

they are not as late as the Chapman sandstones of the same region, 

which are not slaty at all, but are nearly flat and undisturbed by the 

cleavage which has affected all of the older rocks of the region.

Fauna of 1099 D 2 and 8.

1. Monograptus (Graptolithus clintonensis) priodon. r

2. Cardiola interrupta.

3. Coleolus tenuicinctuin.

4. Coleolus aciculum.

5. Orthoceras cf. virgulatum. 

And a few other forms.

The Graptolite shale is believed to be of Silurian age, but the fauna 

is a remarkable combination. Coleolus is as characteristically Devonian 

as Monograptus is Silurian. The specimens of Coleolus present the 

characteristics met with in the typical Mesodevonian forms of New 

York.

The Cardiola is certainly of the type of C. interrupta, which all over 

Europe is characteristic of the Silurian horizon. The three forms are 

certainly from the same rock formation.

The facts deserve more exhaustive treatment than can be given in 

this preliminary report. They confirm the conviction, already reached 

by the author from the study of the Black shales of the Devonian; that 

faunas which we are accustomed to call pelagic, and which we find 

generally in fine-grained, uniform, very thin-bedded, and often calcareous shales, but usually in more or less siliceous shales, are locally of 

great taxonomic importance for the same geologic basin. Nevertheless, 

the faunas themselves contain species which have long stratigraphic 

range, and which can not be relied upon for close determination of 

chronologic position in the geologic series.-

As an illustration, in case we were to find Coleolus tenuicwwtum, or 

any form closely allied to it, though it might be called specifically by 

another name, the containing rock would be referred'on such evidence 

alone to the Devonian. If Monograptus priodon or any graptolite of 

this type of structure were to be found alone, it would certainly be 

referred to the Silurian system. When the association of the graptolite with a true Cardiola of the interrupta type occurs, it is impossible 

to assign the rocks a position higher than Silurian.

The close resemblance of the specimens of Coleolus to the so-called 

embryo tubes of Endoceras proteiforvne of the Ordovician rocks 1 of 

New York, and to similar forms from the Bohemian Basin figured by 

Barrand, suggests the explanation that 'these peculiar fossils, which 

occur in strata of so widely separated age, were internal shells, comparable to phragmocones, and with a chemical composition which 

escaped the solvent effects of the deeper waters in which they were 

probably fossilized.

i Pal. New York, Vol. I, pp. 213 et seq., and pis. 45,46,47.
WILLIAMS.] FAUNAS OF THE SHERIDAN SANDSTONES. 47 

SHERIDAN SANDSTONE.

The Sheridan sandstone is described, in its iithologic features, in 

Part II of this report (p. 132). In its appearance it is a peculiar rock, 

looking like an ordinary sandstone of various degrees of fineness and 

in its coarsest state a pebbly conglomerate.

The color is greenish gray to rather dull brown. When closely 

inspected it is found to be composed of soft and hard rocks, both 

rounded and angular quartz and feldspar; jasper, slate, and argillaceous shale, green, red, and black; and fragments of fossils, corals and 

crinoids, but particularly pieces of brachiopods of size large enough 

to recognize.

The most conspicuous feature about the rock is the angular pieces 

of black slate, which at first suggest fragments of carbonaceous matter, 

but are evidently fragments of the more ancient slates. What is 

petrographically important about them is that igneous materials also 

are associated with them, emphasizing their close association in origin 

with the tuffs and volcanic ash beds with which they are stratigraphically associated.

The evidence is clear, as Is brought out in Dr. Gregory's report, 

that the Sheridan sandstones were formed at a time of, and in a region 

subjected to, violent volcanic eruptions.

Sheridan Plantation. The typical exposure (1097 A) of this sandstone and its fauna is found in Sheridan Plantation, south of the river, 

on the road from Ashland to Presque Isle, a few rods north of the 

Sheridan southern line.

Fauna of 1097 A.

1. Strophomena rhomboidalis.

2. Orthothetes subplanus.

3. Anoplotheca hemispherica.

4. Leptsena transversalis.

5. Orthis, several species.

6. Stropheodonta sp.

7. ? Atrypa reticularis.

8. ? Platystoma sp.

9. Corals, several species.

10. Spirifer cf. radiatus.

A second exposure (1097 E) is on the right bank of the Aroostook 

River a short distance below the mouth of Alder Creek. Here the 

characteristic sandstone is seen with fragments of fossils, but none 

gathered were perfect enough to make out the species.

Other exposures of the same sandstone were seen, one (1097 F) south 

of the same road at the Frenchville store and church, and another 

(1097 H) at Alley's grindstone quarry on the Alley farm, on the right 

bank of Aroostook River about a mile west of the east line of Sheridan 

Township. Fragments of fossils were seen in these several exposures, 

but they were mainly too much broken for identification. At Alley's 

grindstone quarry an undetermined brachiopod resembling Cyrtia, 

but with punctate shell, was seen (catalogued as No. 504), which is also 

present in the shales at Ashland (1098 C 3).
48 COETKIBUTIOISrS TO THE GEOLOGY OF MAINE. [BULL. 165.

New Sweden Township. In New Sweden Township an outcrop 

(1096 A) was seen on-the middle road from Woodland to New Sweden, 

on the west side of the road near the township line. This rock furnished some characteristic species, as follows:

Fauna of 1096 A.

1. Anoplotheca hemispherica.

2. Lepteena transversalis.

3. Pentamerus cf. oblongus.

4. Pleurotomaria sp.

5. Cf. Streptelasma calcula.

6. Cf. Paleodelasma turbinatum.

7. Cf. Cladopora fibrosa.

Drift bowlders. Some of the better-preserved fossils were obtained 

from drift bowlders, catalogued under the station number 1095. As 

there can be no mistaking the fauna and the sandstone in these 

bowlders, the faunas will be given.

The following fauna was found in a drift bowlder (1095 JB) on the 

farm of R. Wither at Woodland:

Fauna of 1095 B.

1. Lepteena transversalis.

2. Strophomena rhomboidalis.

3. Orthothetes subplanus.

4. Stropheodonta cf. perplana.

5. Acidaspis tuberculatus.

6. Cf.Trematospiramultistriata(young).

7. Spirifer cf. niagarensis (young).

8. Pentamerus cf. oblongus.

9. Orthis, two species. 

10. Fragments of undetermined species.

A second bowlder from Woodland (1095 C) contained the following 

species:

Fauna of 1095 C.

1. Lepteena transversalis.

2. Gastropods, several small species.

3. Bellerophon sp.

4. Favosites cf. niagarensis.

5. Corab, several species.

6. Orthis sp.

The following fauna was found in a drift bowlder (1095 D) at Caribou, 

Maine:

Fauna of 1095 D.

1. Lepteena transversalis.

2. Strophomena rhomboidalis.

3. Bilobites bilobus.

4. Cf. Trematospira multistriata.

5. Orthothetes sp.

6. Penta'merus sp.

7. Anoplotheca hemispherica.

8. Several undetermined fragments.

In the township of Mars Hill (1296 F), near the north end of Mars 

Hill, on the west side, in the field at its base, another bowlder was 

found containing the typical fauna, the petrographic characters also 

agreeing with the rock at the typical exposures.
WILLIAMS.] FAUNAS OF THE ASHLAND SHALES. 49

Fauna of 1296 F.

1. Strophomena rhornboidalis.

2. Lepteena transversalis.

3. Pentamerus oblongus.

4. Spirifer radiatus.

5. Atrypa of. obtusiplicata.

6. Atrypa cf. reticularis.

7. Orthothetes sp.

8. Several other brachiopod fragments.

9. A few crinoid segments.

- In the above lists the species cited are generally of small size for the 

species represented. 'Leptcena transversalis is found in almost every 

case, and in each of the very sparse collections is generally represented 

by more than one specimen. The species was evidently very common. 

The fauna of the Sheridan sandstone presents affinities with both the 

Clinton and the Niagara of New York. It is believed that the Sheridan sandstone precedes' the Ashland limestones, whose fauna is 

described elsewhere. However, the actual stratigraphic relationship 

of the limestone to the Sheridan sandstone has not been 'observed. 

Bilobites kilobits is not recorded from the Clinton. On the other hand, 

Anoplotlieca hemispherica is a Clinton species. It represents the upper 

part of the Anticosti group.

ASHLAND SHALES.

Ashland Village. In Ashland Village, along the road opposite the 

hotel, and southward toward Masardis, are several outcrops of limestones, calcareous shales, and sandstones which present stratigraphic 

relationship to one another, but on account of the shear planes and 

semislated structure, as well as 'the intervals unexposed, some doubt 

must be held regarding the accuracy of the interpretation.

The strike of the various exposures examined is northeasterly (N. 

80° E., N. 85° E., N. 30°-50° E.), and the dip northwesterly at 

angles of 60°, 75°, and 55°, thus giving the impression that the 

exposures on the north-south road are lower toward the south.

The irregular, blocklike masses of limestone opposite the hotel are 

met on the southern side by yellowish, weathered shales. There is 

then an interval of several hundred feet south of 1098 A 1 showing no 

rock exposures.

On the east side of the road there is a rock cut (1098 A 3), about 

400 feet south of the hotel. The rocks in this exposure are calcareous, 

thin-bedded shales, somewhat nodular and weathering yellowish from 

iron oxide. Some layers contain nearly pure argillaceous shales, 

others are calcareous. The calcareous layers are all somewhat arenaceous, showing pebbles of quartz, jaspers, and siliceous slates, mingled 

with broken calcareous shells, and an approach to the conditions of 

the Sheridan sandstone. 

Bull. 165 4
50 CONTRIBUTIONS TO THE GEOLOGY OF MAINE. [BULL. 166'.

The fossils are corals, crinoids, and pieces of brachiopods. The 

better specimens of fossils are from the finer shaly layers next the 

calcareous layers. This exposure is 1098 A 3, and is the typical Ashland shale.

Fauna of 1098 A 3.

7. Calymene niagarensis.

8. Cf. Cyrtia n. sp.

9. Spirifer cf. nyuipha Billings.

10. Platyceras sp.

11. Corals, undetermined.

1. Leptaena transversalis.

2. Strophomena rhomboidalis.

3. Orthothetes subplanus.

4. Atrypa reticularis.

5. Orthis flabellites. "

6. Stropheodonta corrugata.

Winslow farm. In the section at Winslow's farm there is the 

same confusion, due to the complication between the bedding and 

cleavage planes. This section was examined and reported by Dr. 

Gregory. It is station 1098 K 1-5, and is in the field east of the 

road, on Winslow's farm, 1^- miles south of Ashland.

At the western end of the section K 1 is a fine-grained calcareous 

sandstone, dark gray in color, with occasional mica grains. It weathers 

to a brown rottenstone. The strike of what appears to be the bedding 

is N. 60° E.; the dip is 40° to 50° NW.

Passing eastward over the edges, the next exposure (K 2) is still a 

calcareous sandstone of the same character, with lenticular masses and 

layers of limestone conglomerate, made up of crinoid and coral fragments and well-worn pebbles of siliceous rock and limestone. The 

contact between the calcareous, shaly sandstone and the conglomerate 

rock is sharp. The whole is much broken up by cleavage and fracture 

planes. The strike and dip are as above.

At the next exposure eastward, 300 feet east of K 2, is K 3, which 

is a fine-grained gray sandstone, weathering brown, little or not at all 

calcareous. The bedding of this rock, as indicated by darker strata, 

has a strike of N. 35° W. and a dip of 10° NE. What were taken for 

cle*avage planes strike N. 45° E., with a dip of 70° NW. This agrees 

better.with the structure of adjacent rocks. Other planes of fracture 

strike N. 35° W., dipping 20° NE., and strike N. 30° W., standing vertical. No fossils were seen in the terrane. Still farther eastward, 100 

feet beyond K 3, an outcrop marked K 4 is seen. This is a sandstone 

shale with calcareous conglomerates. In these calcareous masses are 

fragments of shale, siliceous, well-worn pebbles as large as 3 inches in 

diameter, and fragments of cracked limestone. Beyond this is a large 

mass (K 5) of the fractured limestone, 100 by 8 by 5 feet. No good 

fossils were collected, but the fragments are of the same corals, brachiopods, and other forms seen in the Ashland limestone.

The rocks are in appearance much like those in Ashland Village, 

with the exception that in the latter exposures the conglomerate mass 

is not so clearly expressed. The fossils in the shale correspond closely 

to the fauna of Ashland shale already listed.
WILLIAMS.] THE ASHLAND SHALE. 51

Fauna of 1098 K 8.

1. Orthothetes subplanus.

2. Strophomena rhomboidalis.

3. Stropheodonta perplana Billings.

4. Orthis cf. elegantula.

5. Spirifer bicostatus.

6. Brachiopods, several undetermined 

species.

7. Corals, several species.

8. Crinoid stems.

The Ashland shales, the Sheridan sandstone, and the Ashland limestone contain faunas of the Eosilurian, and from the evidence of 

structure already collected it is difficult to tell their exact relationship 

to one another. The writer's interpretation, with his present knowledge^f the facts, is that the shales are older than the limestones, and 

that the Sheridan sandstones are of the same age as the shales.

The disturbances which occurred in the ash beds and the associated 

Sheridan sandstone may also account for the fragmental condition of 

the Ashland limestone. If so, it is necessary to consider the limestone 

as already consolidated. This might have been the case and still the 

difference in age might be very slight, geologically speaking, for the 

consolidation of a coral reef deposit, though it might take centuries, 

does not require long geologic periods.

In case the volcanic disturbances took place during the''general 

Niagara time, the faunas and the condition of the several kinds of 

rock and their irregular relations may be rationally accounted for. 

In the faunas themselves there is clear evidence for the separation of 

the Square Lake fauna from those now under consideration. The 

Square Lake fauna is clearly equivalent to the Lower Helderberg of 

the New York series, and nearly to the "Delthyris Shaly limestone" 

part of it. The Ashland limestone, Ashland shale, and Sheridan sandstone faunas are all older and may be correlated more closely with the 

Niagara of the New York series.

It is to be observed, however, that the Sheridan sandstone faunas 

combine species of typical Niagara or even Clinton stages of New 

York with other species not found in that region -below the Lower 

Helderberg. We may cite, for instance, Cypricwdvnia lamellosa and 

Phacops logcmi. Not only these, but closely allied species are found 

in the two faunas.

In New Sweden, on the Olivenbaum farm (1096 H), a fine-grained 

shale, calcareous, but with enough siliceous grains to preserve the 

consistency of the rock after the lime is leached out, contains numerous crinoid stems, and among them are recognized plates of Caryocri' 

nms ornatus, which determine the age to be that of the Clinton or 

Niagara of New York. For the present these may be referred to the 

Ashland shales.
52 CONTRIBUTIONS TO THE GEOLOGY OF MAINE.

ASHLAND LIMESTONE.

The limestone at Ashland was referred to by Hitchcock in his report 

for 1861, 1 as follows: .

The next belt of this limestone [referring to seven patches of the Lower Helderberg 

group] noticed is in Ashland, where it has been burned for lime. This bed is largely 

fossiliferous, containing the Favosites gothlandica, a Zaphrentis, Strophomena rhomboidalis, etc. It occurs in three places in this town, viz: In the center, opposite the 

hotel; a mile south, and a mile north of the village. The rock at the southern locality 

dips 70° westerly; but the comparison of all the exposures of the limestone here 

show that it forms the base of an anticlinal axis; consequently the rocks on the east 

and west sides of it are newer, that is, of Devonian age.

Billings, in his paper in the Proceedings of the Portland Society, 2 

does not describe this particular fauna. The fauna from Masardis is, 

however, listed as follows:

Fossils from Masardis. The fossils from Masardis are Crinoids, a new species of 

Orthis, Strophomena rhomboidalis, Spirifera nympha, Atrypa reticularis,, and Clieirurus 

tarquinius. This rock is also Upper Silurian and of the same age as that at Square 

Lake. One of the species, C. tarquinius, is quite common at Port Daniel, on the Bay 

of Chaleur, where it is associated with Bronteus pompilius, so characteristic of the 

Square Lake limestone.

The typical locality for the Ashland limestone is a ledge opposite 

the Ashland Hotel, in Ashland Village. The limestone is mainly a 

pure gray limestone, but much fractured, as if broken in process of 

faulting. This fragmental, brecciated condition is common to it wherever seen, and as far distant as the Dudley farm in Castle Hill (1415 L) 

the limestone, though in apparently comf ormable beds in the series of 

shales and slates, presents the same brecciated appearance.

The study of the fossils has led the writer to associate the following 

outcrops as all belonging to the same general horizon, and if not belonging to a continuous calcareous set of strata the probabilities are in 

favor of regarding them as more or less local calcareous masses in a 

series of calcareous shales of approximately the same geologic age.

Ashland, 1098 A 1. Ledge opposite the hotel in Ashland Village.

1098 F 1. On Gilman's farm, three-fourths mile south of Ashland, along

the Masardis road.

1098 K 4. In field east of road, on Winslow farm, 1 £ miles soutL of Ashland Village.

Castle Hill, 1415 L. On the L. W. Dudley farm, 2^miles west of Mapleton Village. 

Chapman, 1099 D 6. On the W. H. Littlefield farm, west of road along west side of 

Chapman (called "Swanback" road), three-fourths mile south 

of Mapleton line.

1 Agriculture and Geology of Maine, second series (= Sixth Ann. Kept.), Augusta, Me., 1862, p. 240. 

« Proc. Portland Soc. Nat. Hist., Vol. I, Pt. II, pp. 104-126.
WILLIAMS.] FAUNA OF THE ASHLAND LIMESTONE.

Ashland Village. At Ashland Village the following species were

found:

Fauna of 1098 A 1.

1. Strophomena rhomboidalis.

2. Anoplotheca hemispherica.

3. Lepteena transversalis.

4. Orthothetes subplanus.

5. Atrypina imbricata.

6. SpirifernymphaBillings(cf.radiatus).

7. Stropheodonta perplana Billings.

8. Atrypa cf. neglecta.

9. Atrypa cf. nitida.

10. Atrypa cf. intermedia.

11. Orthis sp.

12. Meristella sp.

13. Pentamerus liqueatum.

14. Pentamerus cf. galeatus.

15. Spirifercf. Jaschei (perlamellosavar.)

16. Cf. Trematospira sp.

17. Rhynchonella cf. stricklandi.

18. Rhynchonella cf. nympha, oblata.

19. Rhynchonella, several small species.

20. Mytilarca canadensis.

21. Cypricardinia lamellosa.

22. Cypricardinia cf. depressa.

23. Cypricardinia cf. crassa.

24. Strophostylus elegans.

25. Platyceras cf. retrorsum.

26. Phacops logani.

27. Dalmania cf. anchiops.

28. Bronteus cf. pompileus.

29. Favosites niagarensis.

30. Cf. Polydelasma turbinatum.

31. Cf. Diphophyllum csespitosum.

32. Corals, several undetermined.

Oilman farm, Ashland. At Oilman's farm, Ashland, the following 

species were found:

Fauna of 1098 F1.

1. Strophomena rhomboidalis.

2. Orthothetes subplanus.

3. Meristella cf. laevis.

4. Meristella, several species.

5. Rhynchonella cf. stricklandi.

6. Rhynchonella cf. cuneata.

7. Rhynchonella several undetermined 

species.

8. Rhynchospira formosa.

9. Trematospira cf. globosa.

10. Trematospira cf. formosa.

11. Nucleospira concava.

12. Nucleospira cf. pisum.

13. Spirifer bicostatus.

14. Lichas boltoni.

15. Proetus cf. junius.

16. Avicula textilis.

17. Mytilarca cf. canadensis.

18. Cypricardinia lamellosa.

19. Platyceras, several species.

20. Gastropods, eight undetermined spe- 

	cies.

21. Orthoceras sp.

Wmslow farm, Ashland. In a limestone -lens on the farm of K. 

Winslow, Ashland, the following species were found:

Fauna of 1098 K 4.

1. Corals, several undetermined.

2. Strophomena rhomboidalis.

3. Platyceras, small species.

4. Orthothetes sp.

Dudley farm. Castle Hill. On the Dudley farm, Castle Hill, the 

following species were found:

Fauna of 1415 L %.

1. Strophomena rhomboidalis.

2. Stropheodonta varistriata.

3. Leptsena transversalis.

4. Hyatella congesta.

5. Nucleospira pisurn.

6. Pentamerus oblongus.

7. Lichas boltoni.

8. Dalmanites hmulurus.

9. Palteocyclus rotuloides. 

10. Several undetermined brachiopods.
54 CONTRIBUTIONS TO THE GEOLOGY OF MAINE. [BULL. 165.

The following specimens from the Dudley farm, same limestone, 

were collected by Olaf O. Nylander:

Fauna of 1415 L.

1. Atrypa marginalia.

2. Conchidum knighti (cf. nysius).

3. Pentamerus oblongus.

4. Eatonia medialis var.

5. Leptsena transversalis.

6. Spirifer radiatus (= S. nympha Billings) .

7. Nucleospira pisum.

Littlefield fa/rm, Clux/pma/n. On the Littlefield farm, in Chapman, 

the following species were collected:

Fauna of 1099 D 6.

1. Dalmanites limulurus.

2. Nucleospira pisum.

3. Stropheodonta varistriata.

4. ? Cyrtia sp.

5. Brachiopods, several minute species.

6. Corals.

Two drift bowlders (1095 G and H) picked up by Mr. Olaf 0. Nylander, the one in Fort Fairfield, the other in Presque Isle, contain the 

same fauna, viz:

 Fauna of 1095 G.

1. Strophomena rhomboidalis.

2. Atrypa neglecta.

3. Atrypa (Whitfieldia) nitida.

, Fauna of 1095 H. 

1. Conchidum knighti (cf. nysius).

SQUARE LAKE LIMESTONE.

The Square Lake limestone is a gray f ragmental limestone, chiefly 

composed of fragments of corals, crinoids, and more or less perfect 

fossil shells. The outcrop is on the western shore of Square Lake (or 

Sedgwick Lake), one of the chain of larger lakes in northeastern 

Maine. The f ossilif erous locality is small and near water level, on the 

shores of Square Lake, at a position opposite the eastern head of 

Eagle Lake, in the southwestern quarter of T. 16, R. 5.

The fauna has been collected by several geologists. Specimens of 

the collection made by C. H. Hitchcock and described by E. Billings 

are in the Amherst Geological Museum. But the writer believes, 

from the best information he can obtain, that the types of the descriptions published in the Proceedings of the Portland Society of Natural 

History were destroyed in the fire which demolished the society's 

building.in 1866 (see p. 31).

The fauna of this particular limestone is clearly distinct from the 

other limestone faunas of Aroostook County at present known (viz, the
WILLIAMS.] THE SQUARE LAKE FAUNA. 55

Ashland limestone). It approaches the fauna of St. Helena Island, 

Quebec, and appears, from what is known of it, to be represented by 

the limestones in southern Quebec, about Lake Memphremagog.

Petrographically, the Square Lake limestone differs from the Ashland in its freedom from the fractures and faulting which the latter 

presents wherever seen. This may be a local peculiarity, but it nevertheless serves to confirm belief in the later period of formation, to 

which the fossils testify.

The collection from Square Lake in the hands of the writer was 

made by Olaf 0. Nylander, and wa's purchased for the United States 

Geological Survey. The specimens have been studied in connection 

with the original description of the fauna by Billings, published in 

the proceedings of the Portland Society. 1

A list of the species reported by Billings, and other lists by Bailey 

and Mclnnes,.are given on a preceding page (p. 32). Most of the 

specimens of the present collection are recognized as species named 

by the authors above mentioned. Some of the specimens are not so 

recognized, or are species new to the fauna. The list is given below, 

and follows the order of genera adopted by Billings, indicating the 

-cases of identity by reference to Billings's species by number:

/ Fauna of 1094 A.

1. Favosites sp. (=B1.)

2. Zaphrentis cf. rugulata. (=B2.)

3. Cladopora cf. seriata.

4. Cf. Chcetetes.

5. Cf. Stromatopora.

6. Crinoid stems of several species.

(=B4, 5.)

7. Lyriocrinus cf. melissa.

8. Strophomena rhomboidalis. (=B8.)

9. Strophomena punctulifera. (=B9.)

10. Strophomena indenta. (=B10.)

11. Strophodonta cf. perplana. (=B11.)

12. Strophonella leavenworthana.

(=?B14.)

13. Cf. Leptsena sp.

14. Orthothetes cf. subplanus. (=?B14.)

15. Orthis subcarinata;

16. Orthis oblata.

17. Orthis cf. eminens. (=?Bi3.)

18. Orthis, two undetermined species.

19. Ortnis cf. discus. (=B12.)

20. Bilobites varica.

21. Rhynchonella mainensis. (=B15.)

22. Rhynchonella nucleolata. (=B16.)

23. Rhynchonella aspasia. (=B17.)

24. Rhynchonella bialveata. (=B18.)

25. Rhynchonella pyramidata.

26. Rhynchonella transversa.

27. Rhynchonella cf. vellicata.

28. Eatonia mediaiis. (=B20.)

29. Eatonia mediaiis var.

30. Atrypina imbricata

31. Atrypina cf. disparilis. (=?B21.)

32. Trematospira maria. (=B22.)

33. Trematospira hippolyte. (=B23.)

34. Trematospira multistriata.

35. Trematospira simplex.

36. Rhynchospira electra. (=B25.)

37. Nucleospira pisiformis.

38. Nucleospira ventricosa.

39. Parazygadeweyi. (?=B19) ("Rensselseria Portlandica Bill.")

40. Cf. Cryptonella eximia.

41. Atrypa reticularis. (=B26.)

42. Atrypa reticularis (with fringe).

43. Athyris harpalyce. (=B28.)

44. Athyris sp.

45. Spirifer macropleurus. (=B29.)

46. Spirifer hesione. (=B30.)

47. Meristella princeps.

48. Meristella bella.

49. Meristella Isevis. '

1 Proc. Portland Soc., Nat. Hist., Vol. I, Pt. II, 1869, pp. 104-125.
56 CONTRIBUTIONS TO THE GEOLOGY OF MAINE. [BULL. 165.

50. Meristella arcuata.

51. Strophostylus cf. elegans.

52. Murchisonia hebe.

53. Platyceras, 8-10 distinct forms (?species). (=B31and32.)

54. Gastropods, undetermined. (=?B33.)

55. Orthoceras sp. ? (See B34.)

56. Phacops trajanus. (=B36.)

57. Proetus macrobius. (=B37.)

58. Proetus junius. (=B38.)

59. Bronteus pompileus. (=B39.)

60. Lichas bigsbyi. (=B40.)

61. Cypricardinia larnellosa,

62. Lamellibranch, undetermined.

The age of this limestone is distinctly the same as that of the Lower 

Helderberg formation of New York, as Billings has alreadj^ stated. 

The precise correlation of the Square Lake fauna is to be determined 

by comparison of the two faunas, species by species.

A glance at the lists shows us that there are many species peculiar 

to the Maine facies, and the question arises: Is it possible to recog- - 

nize in the Maine fauna the stage of development corresponding to 

one or other of the stages exhibited by the rich subfaunas of the New 

York section 1? . Although the full discussion of the biologic characteristics of these 

faunas is reserved for a future work, it may be of interest to state 

here the principles upon which correlation can be established on 

grounds of biologic evolution alone, and to illustrate them \>y a typical discussion.

The rhynchonellas of the Square Lake fauna are abundant and well 

preserved, and we have in the several New York faunas of the Neosilurian and Eodevonian abundant representatives of this genus. Therefore the true rhynchonellas, and the forms which, although distributed 

in other genera, are evidently, from an evolutional point of view, 

closely related to them, have been selected.

If fossils can be relied on to signify the stage of evolutional mutation in which they lived, a' study of a single group should furnish 

direct evidence of the stage of the fauna investigated. Many figures 

have been made in the course of these investigations, and.although the 

subject can be satisfactorily treated only in an elaborate illustrated 

monograph, the principles of the study and an indication of the 

importance and definiteness of the results obtained can be indicated, 

preliminary to the preparation of such a monograph, for which much 

.minute study and a great number of illustrations will be required.

££ '

CORRELATION OF THE RHYNCHONELLAS OF THE SQUARE LAKE FAUNA.

GENERIC CHARACTERS.

In estimating the geologic age of any fauna, the biologic relations of 

the species of each genus may be studied separately, and bear their 

own testimony as to the position they occupy in the general evolution 

of the race.
WILLIAMS.] THE GENEKA OF THE BHYNCHONELLID^E. 57

The rhynchonellas are particularly interesting for this purpose, 

because in the typical New York sections of the Lower Helderberg, 

which at first glance seems most nearly related to this Square Lake 

fauna, this genus is represented by an abundance of individuals which 

have presented a wide divergence of form and size. By examination 

of the facts we may expect, therefore, to discover the place occupied 

by the Maine specimens, generically as well as specifically, in the history of the mutation of the race.

The characters of the Rhynchonellidse as a family were notably dif- 

.ferentiated "very early, and have been perpetuated up to the present 

without departure, at any time, from the early derived type," as Hall 

and Clarke remarked in 1894. 1 In the-family twenty-four genera are 

recognized by Schuchert. 2 Schuchert's list is a revision of Hall'and 

Ckirke's classification of 1893-94. 3

Of these twenty-four genera, fourteen are represented by Paleozoic 

species, as follows:

1. Rhynchonella, Fisher de Waldheim, 

1809.

2. Rhynchotrema, Hall, 1860.

3. Rhynchotreta, Hall, 1879.

4. Camarotechia, Hall and Clarke, 

1893.

5. Leiorhynchus, Hall, 1860.

6. Wilsonia, Kayser, 1871.

7. Uncinulus, Bayle, 1878.

8. Hypothyris, King, 1848 (not Phillips, 1841).

9. Pugnax, Hall and Clarke, 1893.

10. Eatonia, Hall, 1857.

11. Cyclorhina, Hall and Clarke, 1893.

12. Rhychopora, King, 1856.

13. Terebratuloidea, Waagen, 1883.

14. Orthorhynchula, Hall and Clarke, 

1893.

Of these genera, the following are reported from rocks of the Lower 

Helderberg or Oriskany age in North America, viz: Rhynchonella, 

Rhynchotrema,Camarotcechia,Wilsonia,Uncinulus, Eatonia. The genus 

Rhynchotreta contains no species of as late age as Lower Helderberg. The genera Leiorhynchus, Hypothyris, Pugnax, Cyclorhina, 

Rhychopora, and Terebratuloidea, so far as present knowledge extends, 

have no species as early as the Oriskany.

In the discussion of the correlation of the Square Lake fauna, which 

contains an Eatonia, we are thus restricted to six genera: Rhynchonella, Rhynchotrema, Camarotcechia, Wilsonia, Uncinulus, and Eatonia. 

Eatonia may be removed from the discussion for the time on account 

of its marked difference from the other forms. It is important, first, 

to ascertain what are the generic characters of the other five groups, 

since the characters for determining the particular age must be sought 

among those which are subordinate to generic rank.

Of these genera, Eatonia is represented in the Square Lake fauna 

by numerous specimens of Eatonia medialis. This species is also 

abundant in the Delthyris Shaly limestone of eastern New York. As

i Pal. New York, Vol. VIII, Pt. II, p. 342.

"- Bull. U: S. Geol. Survey No. 87, p. 121.

8 Kept. State geologist New York,Vol. T T.1S93,p.935; and Pal. New York, Vol. VIII, Pt. II, 1894, p. i!i;5
58 CONTEIBUTEONS TO THE GEOLOGY OF MAINE. [BULL. 165.

the genus is not reported at a lower stage than the Lower Helderberg, 1 

and the species is not known from a lower horizon than the Delthyris 

Shaly limestone, 'the presumption is strong, from this evidence alone, 

that the Maine fauna is not much older than the Delthyris Shaly limestone of the New York section.

Of the family Rhynchonellidse, the following genera are recognized 

in America at lower horizonsx than the Lower Helderberg:

Orthorhynchula............................ .Ordovician.

Ehynchotrema..............................Ordovician.

Rhynchotreta................................Silurian.

Camarotoechia...............................Ordovician-Silurian.

Wilsonia....................................Siluria'n.

Uncinulus...................................Silurian.

Rhynchonella...............................Silurian.

Thus it is shown that the ancestral origin of the Lower Helderberg 

forms must be sought within these seven genera.

The only species of Uncinulus reported from below the Lower 

Helderberg is TJ. stric/dandi, from Waldron, Indiana, Louisville, Kentuckjr, and strata of Niagara age. Rhynchotrema is abundantly represented in the Ordovician by J%. capax, reported from Indiana, Ohio, 

Illinois, Missouri, Wisconsin, Iowa, Minnesota, Anticosti, Manitoba, 

and Hudson Bay. The closely allied species R. incequivalve is reported 

from the Trenton of Drummonds Island, New York; Kentucky; Tennessee; Illinois; Wisconsin; Iowa; Minnesota; New Mexico; Ottawa, 

Canada; Manitoba; and a few other species are reported; but no species 

of this genus is recorded from the lower horizons of the Silurian. The 

Lower Helderberg form R. formosa is the latest representative of 

the genus recorded for America. The genus is thus characteristically 

Ordovician in age, and the propriety of referring the Lower Helderberg species to the genus calls for careful examination.

The fact that the small specimens referred by Hall 2 to RJiynchotrema formosa in the Delthyris Shaly limestone of New York can not 

be distinguished from specimens of the Square Lake fauna which are 

here referred to Rhynchonella aspasia, makes it probable that rhynchonellas of this type may be the direct descendants of the rhynchotremas of the earlier formations. More study, however, will be 

necessary to confirm this view.

By this method .of exclusion we are restricted to the species catalogued under the names Rhynchonella, Orthorhynchula, Rhynchotreta, 

Camarotoechia, Wilsonia, and Uncinulus for the probable ancestors of 

the rhynchonellas of our fauna. The most characteristic rhym-honellas of the New York Lower Helderberg are referred to the group 

called Uncinulus by Bayle. 3

1 In the present paper this genus is reported from the limestone of Castle Hill, 1415 L, in association 

with species which signify Niagara age. (See p. 54.)

2 Pal. New York, Vol. Ill, pi. 35, fig. 3.

» See Hall and Claxke, 1891 and 1893, and Schuchert, 1897.
WILLIAMS.] THE GENUS CAMAROJXECH1A. 59

Orthorhynchula and Rhynchotreta are so far differentiated from thu 

dominant characters of the rhynchonellids that they may be omitted 

from the present treatment as reaching their full specialization in the 

Niagara, and not having direct descendants in the later formations.

The genus Rhynchonella, although strictly speaking having no representatives in the Paleozoic, is still left for the reception of all the 

species whose characters are not sufficiently well differentiated from 

the general family characters of the Rhynchonellidse to have furnished 

any specialist the-means of erecting a new group for them. It is quite 

possible that the Maine rhynchonellas described as 72. aspasia\*y Billings were descended from some one of these earlier rhynchonellas 

not yet separated into special (literary) groups. The other group, 

Uncinulus Bayle, into which a large majority of "Lower Helderberg 

species falls, has for its possible ancestors species of Wilsonia, Camarotechia, and the remnant, not distributed, of Rhynchonella.

GAMAROTGECHIA Hall.

According to the definitions grouped under this name, the distinctive 

characters by which it is marked seem t6 be: (1) The absence of a cardinal process; (2) a median septum in the brachial valve, so divided as 

to make a cavity between the teeth before reaching the outer wall of 

the shell. On these grounds Hall and Clarke include R. ventricosa in 

Camarotoechia, but they distribute all the other rhynchonellas in other 

subdivisions. In their final revision of the Brachiopoda these authors 

state that "the structure of Camarotoechia is possessed by the extravagantly gibbous species R. ventricosa." 1 The forms of the Lower 

Helderberg most closely related to those called Camarotoechia below 

and above that horizon are distributed in another group, called Uncinulus, and the'three characteristic rhynchonellas of the Oriskany are 

again gathered into the Camarotoechia group.

This omission of the camarotcechias, except the one species, from the 

Lower Helderberg faunas is explained by these authors as follows:

At the appearance of the Lower Helderberg faunas, with their multiplicity of 

rhynchonellids, this type of structure appears to have yielded somewhat to the 

robust forms possessing a cardinal process which are referred to the genus Uncinulus. 1

It has already been stated that the Lower Helderberg fauna is 

remarkable "for the abundance of the rhynchonellas of the Uncinulus 

type. These forms in all their superficial characters seem to be in 

the line of passage from the rhynchonellas, called Camarotoechia, 

below and above the Lower Helderberg. It is difficult for one accustomed to recognize genetic affinity in successive faunas not to regard 

the forms of Uncinulus of this period as the direct descendants of 

rhynchonellas of the Camarotcechia and Wilsonia type in the earlier

!Pal. New York, Vol. VIII, Pt. II, p. 191. ' 2 Op. cit., pp. 190-191.
6U CONTRIBUTIONS TO THE GEOLOGY OF MAINE. [BULL. 165.

Silurian, and as the ancestors of the forms called again Camarotoechia 

in the Oriskany and later periods.

In the Oriskany, with no Uncinulus, this group of shells is called 

Camarotechia by Schuchert, although, referred to still another group 

by Hall and Clarke (i. e., Plethorhyncha). 1 It becomes, therefore, 

of special interest to ascertain the meaning and taxonomic value of 

those characters which are used to differentiate these several groups, 

viz, Wilsonia, Camarotechia, and Uncinulus.

Wilsonia is said to have no cardinal process, but median septum and 

dental lamellae like Camarotechia.

Uncinulus is said to have a cardinal process, like Camarotechia. and 

the median septum is described as present; but;the slight division of 

the septum, which is described in Camarotechia as forming a chamber 

between the teeth, is not distinctly seen in the typical Uncinulus.

A critical analysis of the characters upon which the several divisions 

of the rhynchonellas here concerned are based develops the fact that 

the distinctions are formed on various degrees of development of three 

internal characters (1) the cardinal process, (2) the dental lamellae, 

and (3) the median septum. v

The cardinal process is described as absent in Camarotechia, Wilsonia, and Rhynchonella; present and linear in Orthorhynchula, 

Rhynchotrema, and Rhynchotreta; well developed in Uncinulus, and 

large in Eatonia.

The dental lamellae are described as absent in Orthorhynchula, 

Rhynchotrema, Uncinulus (.?), and Eatonia, and as present in Rhynchotreta, Camarotechia, Wilsonia, and Rhynchonella.

In the dorsal valve the median septum is described as thick in 

Rhynchotrema, prominent and divided in Rhynchotreta, prominent 

and with, slight chamber in Camarotechia, present or absent in Uncinulus, rudimentary in Hypothyris, short and bifid in Eatonia, and present 

in Rhynchonella.

It will be noticed that those forms which are conspicuous in the 

Lower Helderberg are characterized by well-developed cardinal process, by absence of the dental lamellae, and by rudimentary development 

of the median septum.

When this diagnosis is compared with the forms which are chiefly 

confined to formations earlier than the Lower Helderberg, it is to be 

noted that in regard to the first and third characters there is a definite 

departure from the earlier stage of development; in the second case 

there is no indication .of sequence, so far as the definitions go.

In both the first and second characters the forms called Camarotechia assume the characteristics of the earlier types. When this 

observation is associated with the well-known prominent development 

of the rhynchonellas, both in size and in numbers, in the Lower Heli Pal. New York, Vol. VIII, Pt. II, p. 191.
WILLIAMS.] .THE EVOLUTION OF THE EHYNCHONELLAS. 61

derberg fauna, it becomes evident that we have here an expression of 

acceleration in development along the very lines of normal evolution, 

and associated with favorable conditions of environment, which are 

expressed in the vigorous fertility and growth of the individuals of 

the race.

This leads to the remark that the described distinctions, which make 

it appear that there were very few, if any, camarotoechias in the Lower 

Helderberg faunas, though they were abundant below and above, are 

not, properly speaking, generic characters, but are mutations expressing temporaiy adjustment of the organisms to the environmental conditions, which in the next stage-were dropped. To use these names 

as they are applied by the authors, the evidence makes it probable not 

only that the Uncinulus of the Lower Helderberg descended from the 

camarotechias of the earlier faunas, but that the camarotrechias of 

the following Oriskany were in direct line of descent from the same 

genus, Uncinulus.

This interpretation implies, of course, that these characters, which 

are taken by the authors to be of generic value, are really plastic 

characters, which are variable in the whole race of rhynchonellas, and 

that their particular expression is a reflex of environmental conditions 

and is not an inherited characteristic. The truth of this proposition 

is confirmed by studying other forms.

When the Oriskany species are critically studied, not only is great 

development observed, but also great plasticity of the same parts. 

The spirifers, the rensselserias, the orthids, and the strophomenoids 

are all conspicuous not only for their great size but for the great 

development of their parts about the interior of the beak, hinge, and 

surfaces of muscular attachments; and not only this, but a series of 

Spi/nf&r are/nosus exhibits great plasticity in the relative strength of 

development of internal features, not only in series living together 

and of the same size and age, but in the degree of development at corresponding stages of growth on different individuals. This plasticity 

is not confined to Spirifer; the other vigorous species, rensselserias and 

ofthids, show the same feature.

Another fact points to the probability that the taxonomic importance 

of these characters, as at present defined, is overdone, if not altogether 

erroneous. In their most valuable revision of the Brachiopoda, Hall 

and Clarke state that the genus Rhynchonella is, from a literary point 

of view, rightly restricted to forms of the type JR. loxia, none of which 

are known to occur at horizons older than the Mesozoic. Nevertheless, when it comes to distributing, in this same literary way, the 

rhynchonellids of the Paleozoic under some name, ninety-five American 

Paleozoic species still have to be called Rhynchonella. 1 The most 

patent reason for this inconsistency is that in these ninety-five species

1 Vide Schuchert.
62 CONTRIBUTIONS TO THE GEOLOGY OF MAINE. [BULL. 165.

the internal characters are not known, and another set of characters, 

those of external form and surface markings, still form the basis of 

the naming and of the taxonomic distribution of the species. There is 

no question as to the great importance of these internal characters for 

purposes of determining the genetic relationship of organisms, but it 

is also a fact that the external or surface characters do not cease to be 

of similar value.

The old use of external characters failed to give a correct classification in some cases, either because the differences were not discernible 

from the previously observed characters, or because they were not 

rightly interpreted. In the first casB more evidence was all that was 

needed to settle the difficulty; but faulty interpretation of their meaning can be made regarding the internal as well as the external characters the important as well as the trivial characters.

But the point to which attention is called by these remarks is that 

the taxonomic rank of characters rests primarily upon their relative 

fixity, and not upon their supposed importance in the individual 

economy of the organism. If any character suffers mutation in transmission it can not be counted as of high taxonomic value. This does 

not mean that a particular part or organ of an organism which is 

possessed by, let us say, all the members of an order does not vary, 

but that that particular in which the part varies is not an ordinal 

character, but is only^)f specific or varietal value.

When we observe, as we do in the Oriskany, nearly every different 

genus represented by individuals which are large and coarse when compared with their fellows in other formations, the element of size is 

shown to be of insignificant taxonomic value. So when we observe 

the relative strength of development of muscular attachments and processes associated with the manipulation of the two valves of a hinged 

brachiopod, varying at the same stage of growth "in individuals of the 

 same species, it is evident that characters based upon proportionate 

strength of development of such parts can not be relied upon for 

generic distinctions.

The wilsonias and Uncinulus constitute a characteristic group t>f 

rhynchonellas in the early and, particularly in the later, Silurian 

faunas. But a comparison of these forms with each other shows that 

the wide range of variability of the characters which are used to distinguish them as groups is more characteristic than any or all of the 

characters by which their diagnosis is attempted. It is true that 

specimens can be picked out illustrating the characters described, but 

it is as true that specimens can be easily found in,full collections which 

can not be discarded from the group but which lack one or other of 

what are described as typical characters.

Generic characters, to be of taxonomic value, must be distinguished 

from variatal and specific characters by their greater fixity, or what
PLATE I
PLATE I. 1

RHYNCHONELLAS OF THE SQUARE LAKE LIMESTONE.

(Numbers in parentheses refer to catalogue numbers of the specimens figured.)

Figs. 1, 5, 9. Dorsal, front, and ventral views of broad, flat form of RhynchoneUa 

vellicata Hall. (M 45.)

Figs. 2, 6, 10. Dorsal, front, and ventral view of median form of RhynchoneUa. 

vellicata Hall. (M 45.)

Figs. 3, 7, 11. Dorsal, front, and ventral view of narrow form of R. vellicata Hall. 

(M 45a.)

Figs. 4, 8, 12. Dorsal, front, and ventral view of a form intermediate between 

Hall's R. vellicata and R. mainensis. Billings, labeled R. mainensis Bill. var. (M 21).

Figs. 13, 16, 19. Dorsal, front, and ventral view of a very perfect specimen of R. 

mainensis Bill., near the form of Billings's type.. (M 22.)

Figs. 14, 17, 20, and 15, 18,. 21. Dorsal, front, and ventral views of the broader, 

flatter forms of R. mainensis Billings. (M 19.) '

Figs. 22, 23, 24. Dorsal, front, and ventral views of R. mainensis Billings, approaching the form R. abrupta Hall. (M 19.)

original figures from which? Pis. I and II were prepared were made directly from the specimens by a patented photographic process by N. W. Carkhuff. 

64
U.S.GEOLOGICAL SURVEY BULLETIN NO. 155 PL. I

RHYNCHON ELLAS OF THE. SQUARE LAKE LIMESTONE.

THE HELfOTYPE PRINTING CO., BOSTON.
PLATE II

65 

Bull. 165 5
PLATE II.

RHYNCHONELLAS OF THE SQUARE LAKE LIMESTONE.

(Numbers in parentheses refer to catalogue numbers of the specimens figured.)

Figs. 1, 4, 7. Dorsal, front, and ventral views of R. mainensis, van, with characters 

intermediate between that form and R. mutabilis Hall and R. nudeolata Hall. (M 22.)

Figs. 2, 5, 8. Dorsal, front, and ventral views of a broad, short beaked form of R. 

mainensis Billings. (M 19.)

Figs. 3, 6, 9. Dorsal, front, and ventral views of R. nudeolata Hall. (M 23.)

Figs. 10,13, 16. Dorsal, front, and ventral views of R. mainensis, var., approaching 

R. nudeolata Hall. (M 21.)

Figs. 11, 14, 17. Dorsal, front, and ventral views of a typical form of JR. mainensis 

Billings. (M 22.)

Figs. 12, 15, 18. Dorsal, front, and ventral views of Rhynchonella pyramidata Hall. 

(M 20.)

Figs. 19, 20, 21. Dorsal, front, and ventral views of R. nudeolata Hall, of the form 

figured by Billings. (M 23.) 

66
U.S.GEOLOGICAL SURVEY BULLETIN NO.I65PL.II

ill

rr|

-4tiii/

RHYNCHONELLAS OF THE SQUARE. LAKE LIMESTONE.

THE MELIOTYPE PRINTING CO., BOSTON.
WILLIAMS.] EHYNCHONELLA SPECIES OF SQUAEE LAKE FAUNA. 67

may be defined as their more exact reproduction or transmission in 

generation. What distinguishes these Lower Helderberg rhy nchonellas 

as a whole is their great luxuriance and fertility, together with a great 

plasticity in the very characters which have been selected for both 

specific and generic diagnosis. This plasticity and increased range of 

variation, associated with the evidence of favorable conditions of life, 

does not point to restriction of the interbreeding which is supposed to 

distinguish specific groups, and it certainly does affect separate genera. 

With these remarks upon the generic characters, we may next 

examine the particular species present in the fauna and discuss their 

significance for purposes of correlation.

SPECIES OF RHYNCHONELLIDS IN THE SQUARE LAKE FAUNA.

(See Pis. I and II.)

In the Square Lake fauna there are a considerable number of forms 

which fall at once into the Rhynchonella group of brachiopods, and which, 

upon a slight comparison with described species, are seen to be closely 

allied to species of Rhynchonella of the Lower Helderberg formation. 

In order to determine the geologic horizon of the fauna, not only is it 

necessary to determine the identity of these species, but, whether 

identical or not, it is necessary to ascertain the precise stage in the 

evolution of each phylum, or race, to which the particular species 

belong. This may- be reached by ascertaining how these particular 

species a.re related morphologically to forms whose place in a typical 

geologic section, such as that of New York, is known.,

The following species of Rhynchonella have been recognized in the 

Square Lake fauna by Billings, and later by the writer:

Ehynchonella mainensis Billings, M 19,

M22.

Rhynchonella nucleolata Hall, M'23. 

Ehynchonella pyramidata Hall, M 20. 

Ehynchonella pyramidata Hall var. a,

M24.

Ehynchonella vellicata Hall, M 45. 

Ehynchonella aspasia Billings, M 26. 

Ehynchonella bialveata Hall. 

Ehynchonella transversa Hall.

There is no difficulty in recognizing, in the collection under investigation, specimens similar to those referred to by Billings in his original 

description of the fauna. Because of the rarity of the volume in which 

the species were originally described (the papers as well as the specimens having been burned in the fire which destroyed the Portland 

Society building in 1866), Billings's original description is here transcribed: . EHYNCHONELLA MAINENSIS, n. sp.

PI. Ill, fig. 4, Rhynchonella mainensis, n. sp.

Description. Transversely ovate, length about one-fifth or one-sixth less than the 

width. Ventral valve moderately convex, most elevated at about one-third the
i

68 CONTEIBUTIONS TO THE GEOLOGY,OF MAINE. [BULL. 165.

f

length from the beak; mesial sinus deep in front, flat in the bottom, the side sloping 

outward, becoming obsolete at two-thirds the length of the shell; beak well defined, 

incurved down to the umbo of the dorsal valve; on each side of the beak a small 

ovate excavation extending toward the cardinal angles; umbo only slightly elevated, 

this valve being only half a line longer than .the dorsal. Dorsal valve strongly and 

uniformly convex, nearly hemispherical, most elevated in the upper half, with a wide 

flat mesial fold elevated about one line above the general surface at the front margin, 

but becoming obsolete at two-thirds of the length; beak pointed, well defined, but 

only visible when that of the opposite valve is broken away.

Surface with from twenty-five to thirty ribs, of which there are from four to six on 

mesial fold and from three to five in the sinus. All the ribs die out before reaching 

the beak, the upper one-fourth of the shell being smooth. On approaching the front 

margin the ribs are obscurely angular, but toward the upper part of the shell they 

are neatly rounded but not strongly elevated.

Width, ten to twelve lines; length, about one-fifth .or one-sixth less than width; 

depth of both valves, six to eight lines; depth of the sinus in the front margin of the 

dorsal valve, about three lines.

The curvature of the ventral valve from the beak along the median line and the 

bottom of the sinus is a uniform arch somewhat most abruptly curved in the upper 

half. This curve can not be seen in the profile of the whole shell, as it lies partly in 

the sinus.

This species is closely allied to R. abrupta Hall, Pal. N. Y., vol. 3, p. 228, pi. 32, 

fig. 3, but differs therefrom in being more ventricose in the upper part of the dorsal 

valve, in having the ventral valve uniformly arched along the sinus instead of 

abruptly bent upward nearly at right angles to the dorsal valve, and in not having 

the ribs in the sinus bifid at their extremities.

Locality and formation. Square Lake, Maine; Upper Silurian. 1

RHYNCHONELLA NUCLEOLATA Hall.

R. nudeolata Hall, 'Pal. N. Y., vol. 3, p. 227, PL XXI, figs, 1 and 2. PL III, fig.'5. 

Rhynchonella nudeolata; a, dorsal, b, front, and c, side views.

Description. This species is smaller than R. mainensis, and has the surface marked 

by only fifteen or twenty ribs toward the front, the upper part being smooth. The 

outline is subcircular or subpentagonal; the width varies from a little less to a little 

greater than the length. Ventral valve depressed convex, a small portion of the 

margin abruptly deflected to meet the margin of the dorsal valve; the mesial sinus 

becomes obsolete about the middle of the shell, but on approaching the front margin 

the portion of the shell constituting the bottom of the sinus is suddenly bent almost 

at right angles to the plane of the lateral margin and forms a projection which fits 

into a deep oblong notch of the opposite valve. Beak small, pointed, apparently 

incurved so as just to cover that of the dorsal valve. (It is not well preserved in the 

specimen examined.) Dorsal valve'very convex, strongly elevated in the first half, 

where there is a short mesial fold; the upper half of the shell varies greatly in the 

amount of its gibbosity, being in some depressed convex, and in others rather 

strongly and broadly tumid; beak angular, prominent, but concealed beneath that 

of the ventral valve. There is a short mesial septum extending from the beak of 

this valve nearly half the length, which can be distinctly seen when the shell is partially or wholly removed.

Of this species there are only two good specimens in the collection from Square 

Lake. It is very difficult to say whether they should be referred to R. nudeolata or 

to R. pyramidata. One of them has the dorsal valve strongly convex in the upper

iProc. Portland Soc. Nat. Hist., Vol. I, Pt. llf p. 110.
WILLIAMS.] BILLINGS'S SPECIES OF RHYTSTCHONELLA. 69

half, and the other depressed convex, but they both unquestionably belong to the 

same species. 

Locality and formation. Square Lake, Maine; Upper Silurian. 1

RHYNCHONELLA ASPASIA.

PI. Ill, fig. 6, Ehynchonella aspasia. Dorsal and side views of a young individual. 

. The large specimens have the base not so distinctly rectangular, but a little rounded.

Description. Transversely subelliptical; greatest width about one-fourth more than 

the length. Ventral valve narrowly convex on the umbo; a mesial sinus commencing at about one-fourth of the length from the beak, and growing deeper with an 

uniform curve to the front margin, where it is full one-half the whole width of the 

shell and deeply indents the opposite valve; on each side of the sinus one or two 

ribs more prominent than the others; outside of these the surface is depressed convex, and shows a tendency to become slightly concave close to the margin; beak 

small, closely incurved and nearly, if not quite, in contact with the mnbo of the 

opposite valve. Dorsal valve rather strongly but narrowly convex along the median 

line; sloping to the sides; mesial fold strongly elevated in front, dying out at about 

half the length. Surface in young specimens with seven or eight strong angular ribs 

on each valve; one rib in the sinus and two on the mesial fold. In old specimens, 

about twelve ribs on each valve, of which there are two or three in the sinus and 

three or four on the fold.

The greatest width is about the middle of the shell. On a side view of a young 

shell the most elevated point of the dorsal is just at the front margin on the top of 

the fold, and the base has a rectangular form. In the old specimens, on a side view, 

the front is not so decidedly angular, but slightly rounded. Width of the largest 

specimen, 7 lines; length, 6 lines. Width of the smallest specimen, 4£ lines; length, 

3£ lines.

This species is allied to both R. altiplicala and E. acutiplicata, Hall, Pal. N. Y., 

vol. 3, PI. XXXIII, and seems to stand between them. It is proportionally wider 

than the former and not so numerously ribbed as the latter. It may be that a 

greater number of specimens would afford us the means of uniting all three.

Locality and formation. Square Lake, Maine; Upper Silurian. 2

The typical Rhynchonella mamensis Billings3 is plainly a representative of R. abrupta Hall of the Delthyris- Shaly limestone of New York. 

The first distinctive character noted by Billings is the greater ventricosity in the upper part of the dorsal valve of the Maine species. This 

is a character belonging to the earlier form R. mutdbilis. At the Delthyris Shaly limestone stage of mutation, of the forms with the higher 

number- of plications, R. abrupta is the extreme in this character of 

early gibbosity. The extreme of gibbosity at this stage pertains to 

the forms with fewer plications, as R. nudeolata. This variation is less 

extreme in R. vellicata, and among the few specimens in'the present 

collection there are those passing to R. velUcata, and even thinner than 

the typical R. vellicata of New York.*

If the modification were associated purely with geologic range 

it would be inferred that the Maine fauna was younger than the R. 

mutabilis stage in New York, and older than the R. abrupta stage.

1 Proc. Portland Soc. Nat. Hist., Vol. I, Pt. II, p. 110. . 3 See PI. II, figs. 11,14,17. 

a Op. cit., Vol. I, Pt. II, p. 111. «See PI. I, figs. 1,6,9.
70 COFTKIBUTIONS TO THE GEOLOGY OF MAINE. [BOLL. 165.

But, judging from the wide range of plasticity expressed in specimens 

of the Delthyris Shaly limestone, as well as in those of the Square Lake 

limestone, it is assumed that the limits of plasticity of this character 

were as great in the Delthyris Shaly'limestone as in the Maine representatives, and that the difference in the description is chiefly subjective and depends upon the selection of type specimens made by 

Billings for his species R. mainensis.

The second distinctive character noted by "Billings is "the ventral 

valve uniformly arched along the sinus, instead of abruptly bent upward 

nearly at right angles to the dorsal valve." This is a characteristic of 

all the Square Lake representatives, except R. pyramidata. 1 But, as 

between the R. mutabilis and R. abrupta, the Maine forms are decidedly 

nearer the mutation R. abrupta than JR. mutabilis.

The third character mentioned by Billings the absence of the bifid 

extremities of the plications is not a constant character, as some of 

the Square Lake specimens are bifid at the extremities. 2 This character 

is associated with the abruptness of the bending of the surface at the 

front. In forms of the R. pyramidata type this character is conspicuous; and, also, on a comparison of the successive mutations of 

the series, it is observed to be more conspicuous with advance of time. 

From such a comparison it seems probable that the angularity of the 

front, the sharp bifid development of the terminal part of the plications, the general flattening of the shells during the first half of the 

growth, and the dominance of the fewer-ribbed specimens, are characters associated with advancing evolution, and hence are- more conspicuous at the later stages of mutation.

Passing from the characters of typical R. mamensis of Billings to 

closely allied forms associated together in the Square Lake faumt, the 

range of variation covers the same characters expressed by the variations in the Delthyris Shaly limestone series. On the other hand, the 

variant with the high number of plications, flat form, and low sinus 

and fold, called R. vellicata by Hall, is well represented in the Square 

Lake fauna;3 also the forms with fewer plications but gibbous form, 

the variant R. nudeolata Hall, and those with few strong plications, 

angular beak, abrupt geniculated front, called R. pyramidata Hall, 

are represented together in the collection in hand. That these differences are purely variational is well shown by two specimens in the 

Square Lake fauna.

The first is a specimen of R. nudeolata (23/M), 4 which, on the young 

part of the shell about the beak, exhibits the full quota of plications, 

twenty-eight to thirty being clearly visible. Upon passing a prominent concentric line of growth in midst of shell the plications lessen, 

and at the front the number that can be counted is but eighteen, thus

1 See PL II, figs. 12,15,18. 8 See PI. I, figs. 1-12.

2 See PI. II, figs. 13,15. * PI. II, fig. 21.
WILLIAMS.] COMPARISON WITH NEW YORK SPECIES. 71

showing the variational tendency to diminish the number of plications, 

which is a conspicuous feature of the dominant representatives of the 

race when looked at in geologic succession.

The second specimen is a variety of R. pyramidata^ which typically 

exhibits few plications as soon as they are evident in the beak region. 

This variant is much narrower in form than the typical specimens, and 

exhibits but a single plication in the fold instead of three, as is usual, 

and only four on each side, the typical number being five. In this 

case the central plication is longer and more prominent and more 

elevated from the surface than is usual. If this were represented by 

many individuals holding these characters without variation, it would 

undoubtedly be considered as a good species; but if we regard the 

rhynchonellas of this group as particularly plastic in these elements of 

form, the specimen is to be regarded as a marked variational form 

of the R. pyramidata type, carrying its peculiarities of JR. pyramidata 

a step further away from the central form in the direction of the yariation which the normal pyramidata has assumed. Both of these 

aberrant forms are evidence of the nature of the plasticity among the 

individuals living together at the time of the Square Lake limestone.

When it is observed that the same characters are those upon which 

dominant groups of individuals, called species, are founded, not only in 

this fauna, but in the several New York faunas of the Lower Helderberg, it becomes evident that what constitutes the limitation of a 

species is the checking of the plasticity of the several characters at the 

same point in numerous individuals.

This characteristic of specific groups is brought out by comparing 

species of, successive faunas. In a single fauna, like this Square Lake 

fauna, it is possible to see only the combination of characters marking 

the dominant forms and those divergent forms associated with them 

which, because of their rarity, are clased as varieties. In a series of 

successive faunas it is also possible to see the changes in combination 

of characters marking the successive species, each successive species 

bearing the relation of mutant to the earlier forms, but the dominant 

combination is not a direct mutant of the earlier dominant forms, but 

may be a mutant of some of the inconspicuous varieties.

In the New -York Lower Helderberg we find a convenient series 

upon which to make these observations. The rhynchonellas of this 

general group are described by Hall under the following names: 2 For 

the Lower Fentamerus fauna, R. mutabilis Hall; for the Delthyris Shaly 

limestone, R. nudeolata, R, dbruptd, and R. vellicata Hall; for the 

Upper Pentamerus, R. ventricosa, R. nobilis, and R. campbellana; for 

the Oriskany, R. speciosa; and other species may be added, but their 

divergence is so extreme as to bring in other questions which may be

1 Not figured ou these plates. 2gee Pal. New York, Vol. III.
72 CONTRIBUTIONS TO THE GEOLOGY OF MAINE. [BULL. 165.

left for remark at another occasion. The following deductions may 

be drawn:

1. These several described species evidently belong to a common 

race, whatever other species may belong to the same race, or whatever 

opinion we may have as to their generic relations.

2. It is also clear that the dominant characteristics of -It. inutahilis t»

of the first stage are represented at the second stage by R. nucleolata, 

at the third stage by R. ventricosa, and at the fourth stage by JR. speciosa in part.

4. RhyncJwnella mutahilis of the first stage has the plications low, 

rounded, and not sharply developed; it shows various degrees of convexity, but marked gibbosity is the dominant characteristic; the fold 

and sinus are low and inconspicuous. The curvature of surface is 

gradual and even, so that nowhere does the surface present &ny marked 

or abrupt angles I. e., any marked and sudden changes in the direction 

of growth of the shell. There is considerable variation expressed, 

but these characters prevail so dominantly among them all that there 

seem to be no characters by which to break up the series into separate 

specific groups. When the succeeding species are compared with this 

one, the differences are seen to consist chiefly in the intensifying of 

characters which are expressed here in a medium stage of development.

4. There are evident at the second stage, the Delthyris Shaly limestone, three dominant forms («, J, c) which are closely related to R. 

mutabilis, but differ by the intensifying of the central and the two 

extremes of character-combinations seen in that species. These are:

a. The median type, which preserves the full complement of plications, but they are more sharply defined upon the surface. The gibbosity is distinctly less, though still conspicuous; the fold and sinus 

are well defined on the latter half of the growth of the shell, and the 

front is rather abruptly angulated, though not strongly so. This is 

called R. abrupta, and in the thinner forms R. vellicata.

1). The extremely gibbous forms, which have a reduced number of 

plications that are fainter at the beak but become stronger with growth 

and more angular; the fold and sinus are well defined on the mature 

half of the shell. This is R. nucleolata.

c. The form with least tendency to gibbosity, which grows directly 

from the beak, with flat surfaces, slightly arched plications, few and 

not evident at first, but well defined toward the front; the fold and 

sinus not sharply developed till late in the growth; and finally at the 

edge along the sides and at the front a sharp angular turn in growth, 

making a flat, almost square, front and sides. This is R. pyramiduta.

5. The third stage shows two dominant forms:

a. The median type is further elaborated by an increased growth 

to the front, making an oval-elongated species with full complement of 

plications, well defined; the fold and sinus evident at front, and the
WILLIAMS.] SPECIES OF THE DELTHYEIS SHALY LIMESTONE. 73

latter half of the growth larger in size, thus making a narrow form 

with sharper beak. This species is R. nobilis.

1). The second dominant group of the Upper Pentamerus is a further mutation of R. nucleolata of the preceding .stage; the plications 

are still fewer, and the gibbosity is still more extreme. This is R. 

ventricosa.

6. In the Oriskany the elongate-oval form is an expression of the 

same tendency seen in R. nobilis, but it is associated with smaller number of ribs and less dominant fold and sinus and much greater size 

than in the Lower Helderberg forms. This is R. speciosa.

A study of the plications on the forms from the several Lower 

Helderberg localities of New York shows the intimate relationship 

between the evolution of these characters and the ages, or, more 

strictly, successive stages in geologic history, at which they occur.

Without going outside of the published report of the facts as found 

in Vol. Ill of the Paleontology of New York, the following points 

are in evidence:

A. R. mutahilis is reported as having twenty to twenty-six plications in all, and six to eight on the fold. This is the Lower Pentamerus species. 3

B. R. pyramidata, thirteen to twenty-two, and four to six on fold. 

R. nucleolata, fifteen to twenty-three, and four to five on fold. 

R. abrupta, twenty-five to thirty-three, and seven to eight on fold. 

R. vellicata, twenty-four to thirty-six, and six to eight on fold.

These are the Delthyris Shaly limestone species. It will be observed 

that R. 'mutahilis is strictly intermediate, and the first two species are 

different by having less and the second two by having more plications 

than the earlier species.

C. The next series are from the following stage, the Upper Pentamerus:

R. ventricosa, fourteen to twenty, and three to four on fold. 

R. campbellana, twenty-two to twenty-four, and five to six on

fold. 

R. nobilis, twenty-six to thirty-two, and six to eight on fold.

This set exceeds the extremes of the set of the preceding stage in 

some particulars, but the limit of variation in each case is less. This 

latter characteristic, which may be described as a tendency to restriction of variation, is to be observed in a collection of specimens by the 

fact that the specimens in a collection of R. ventricosa are more uniform than those in a similar collection of the species R. pyramidata; 

or a set of specimens of R. nobilis may be said to be more uniform 

than a set of specimens of R. vellicata.

D. When we pass up to the Oriskany the plications are conspicuously increased, with decided increase in the size of the specimens.

Again taking the reported statistics, supplementing them with a
jfW- 1 '' - ' .

74 CONTKIBUTIONS TO THE GEOLOGY OF MAINE. [BULL. 165.

count of the plications as figured for R. speciosa and R. multistriata, 

^we find the following:

R. speciosa, twenty-seven to thirty-three plications, not bifur- 

' eating on body of shell.

R. barrandi, thirty to forty plications, rarely bifurcating.

JR. ramsayi, thirty-six to forty plications.

R. pliopleura, sixty-seven to seventy plications, bifurcating.

R. fitchana, seventy-five plications, bifurcating.

R. principalis, eighty plications, occasionally bifurcating.

R. oblata, seventy-five to eighty plications, occasionally bifurcating.

R. multistriata, seventy-five to eighty plications, bifurcating, 

finely striate.

Before a careful study of these facts (upon actual series of specimens) 

is made it would be unscientific to attempt to state the actual limits 

of specific variation; but it is evident that the Oriskany species are 

as a series more numerously plicated; the fold and sinus, particularly, 

hold more plications; the size of the specimens is greater and the 

bifurcation of the plications is a common characteristic, causing them 

to differ from the series of forms which, on the theory of descent, 

must be supposed to contain their ancestors.

Without, at the present time, turning aside to investigate the actual 

facts regarding the New York Helderberg series, it is evident that the 

morphologic mutation which the representatives of this group of 

. rhynchonellas expressed included the following particulars:

The variations which were expressed by the individuals of the Lower 

Pentamerus single species R. mutabilis were carried to the extent of 

making greater divergence of form in the Delthyris Shaly limestone 

stage. In the Upper Pentamerus the extremes were still greater, but 

the variation was less, and the dominance in number of individuals is 

among the extreme and not the median types.

In the Oriskany the characteristic mutation resulted in great size 

of individuals, associated with which was a decided increase in the 

number of plications, chiefly by bifurcation. This last fact, if taken 

in connection with the normal variability or, more strictly speaking, 

plasticity in the number of plications, suggests the inference that the 

increment in the number of plications is associated with expansion of 

the surface of the shell laterally. In case this took place very early 

in development, bifurcation resulted with growth. But when vigorous 

growth took place in the middle and later stage of individual development, the resultant effect was gibbosity of form. When, however, 

vigorous growth began early and continued throughout development, 

the bifurcation of the ribs continued to take place and great size was 

attained, as in the Oriskany forms.
WILLIAMS.] SECOND SERIES OF KHYNCHONELLAS. 75 .

To generalize this theory of their growth, it may be said that the 

characteristic elements of plasticity, which at the Pentamerus stage 

were confined to early stages of individual development, became 

conspicuous and dominated the growth of relatively later and later 

stages of development with the passage of time. This accords with 

the general trend of hypothesis advanced by Hyatt.

Anothe°r series of rhynchonellas is represented by three fairly welldifferentiated species described or referred to by Billings under the 

names It. aspasia and " It. like bialveata" Hall; and another form 

referred to under the description of the former in likening the species 

R. aspasia to R. altiplicata and R, acutiplicata Hall, and called "old 

specimens."

In the present collection the larger forms of this series described 

by Billings as R. aspasia ("7 by 6 lines in size") are not in evidence, 

but one of the smaller forms shows the characters corresponding to 

the description given rather than to the figures on the plate. 

The two species in the present collection, with several well-marked 

specimens each, are referable to R. aspasia Billings and R. bialveata 

Hall. These belong, further, to a group of species of the Delthyris 

Shaly limestone in New York, including also the species R. altiplicata, 

R. transversa, R. rudis, and in the Lower Pentamerus the form evidently referred to by Hall as "R. semiplicata Conrad." Possibly R. 

formosa and R. sulciplicata Hall also belong to the series.

The specimens from the Maine fauna here referred to R. aspasia 

Billings (and, judging from the descriptions, the series of species 

described from New York by Hall may be included) are marked by 

their triangular form, with rather distinct narrow beaks, straight sides, 

few angular plications, a well-developed fold, and sinus at the front of 

the shell reaching halfway to beak. The shells are, in general, rather 

thin, and more or less flat along the middle part .of the surface.

The description of R. aspasia by Billings seems to cover two forms, 

while the figure 1 in the descriptive paper applies to the typical form 

only. The following statement is referred to: "In old specimens, 

about twelve ribs on each valve, of which there are two or three in the 

sinus and three or four in the fold," and later the less angular rounded 

form of the sides of "old specimens."

The association of these "old" and larger spe°cim^ns with the 

smaller typical forms brings in the characters which by Hall are made 

to distinguish other species, such as R. rudis, R. transversa, and 

apparently some of those referred to R. formosa on the plates. Resemblance to R. acutiplicata Hall is evident in the larger of the specimens in the collection.

Billings's figure well represents the typical characteristics of the 

larger of the specimens referred to this species; another of our specii PI. Ill, fig. 6.
76 CONTBIBUTIONS TO THE GEOLOGY OF MAINE. [BULL. 165.

mens is well represented by Hall's figs. 6 a, J, and c of PI. XXXIV, 1 

which by Hall are referred to Conrad's species It. semiplicata?. One 

of the specimens has the smooth condition of surface near the beak 

described by Conrad as characteristic of R. semiplicata, but examination of our specimens makes it evident that this is here due to exfoliation, 

and that specimens, when well preserved, have evident plications as 

near to the beak as they can be distinguished for smallness of size. 

Fig. 3 of PI. XXXV well represents another specimen. This" is called 

."young of R. formosa" by Hall. t

The forms described and figured by Billings as It. aspasia, excluding, 

those he regarded as old specimens, should be taken as the type of his 

species. This will leave out certain forms, of as small size as the 

others, in which the sinus has two or three, and the fold three or four, 

plications. This latter form the*writer takes to be a simple variety, 

but as it is a distinct form it confuses the definition of Billings's 

species to leave it among the other small forms, since only old 

specimens were supposed to have this character by Billings, whereas 

study of the specimens makes it evident that from the earliest stage of 

growth at which the surface plications are visible to the front of the 

shells no increase in number of plications occurs in any of this group 

of rhynchonellas.

The use of Billings's name, although the same forms were previously 

recognized and figured by Hall, may be defended on the ground that 

Billings clearly distinguished, defined, and figured the diagnostic 

characters of the form, while Hall distributed the same form under 

more than one species and confused it with others of different form. 

Having thus recognized Billings's species R. aspasia and its typical 

characteristics, it should be noticed that there are specimens in the 

Square Lake fauna presenting the variant characters represented by 

Hall's figs. 12, 145, of PI. XXXIV, referred by Hall to R. transversal, 

but differing from 6 a, 5, c, of the same plate by the possession of 

two more plications in the fold and in the sinus, the plications on the 

side being finer and more distinct. The writer has recognized this as 

R. transvwsa Hall, selecting as typical, from the several forms included 

by Hall under that name, one which seems to constitute the median 

combination of characters. It would be altogether improbable that any 

two paleontologists would distribute the original specimens figured by 

Hall under the. names R. inutilis, R. transversa, R. rudis, R. planoconvexa, R. sulciplicata, and the Delthyris Shaly limestone specimens 

of R. formosa in the same groups under which they are originally 

described, or under any groups that would be described as specifically 

distinct by another person. By this remark it is not intended to express 

the opinion that there may not be distinct specific groups developed 

among the forms described under these names, but certainly it is

iPal. JStew York, Vol. III.
WILLIAMS.] CORRELATION OF THE FAUNA. 77

difficult to form, from a study of the figures and descriptions, a clear 

notion of what particular combination of characters the author had in 

mind when sorting out and labeling the figures and applying specific 

names to them.

The specimens referred to by Billings as "like R. bialveata" are 

represented in the collection and evidently belong to this species. At 

least one of the specimens agrees fairly well with Hall's description, 

though the figures are poor and do not convey a correct idea of the 

true form and characters. The plications and the boundary plications 

of the sinus and fold are very sharp and distinct, even close up to the 

beak region. The two plications of the fold of the dorsal valve begin 

very close up to the beak, but they are depressed below the surface in 

a groove, and as they run out toward the front they come up even with 

the surface about midway and constitute a prominent fold at the front. 

This constitutes a well-differentiated specific group in the Square Lake 

fauna, the individuals of which evidently were naturally small. The 

narrow form, the abrupt sides, the sharply angular plications, and the 

mode of development of fold and sinus are dissimilar to the young 

stages of the other rhynchonellas of the fauna. These two species, 

R. aspasia and R. bial/veata, correlate the fauna with the Delthyris 

Shaly limestone stage of the Lower Helderberg.

Applying this method of determining the stages of evolution of a 

series to the correlation of the Square Lake fauna, the results point to 

a stage of mutation corresponding to that of the Delthyris Shaly limestone of New York, but not in its full expression. The Square Lake 

forms are nearer to the Lower Pentamerus than to the Upper Pentamerus stage. This is indicated by the fact that the dominant form, 

named R. mainensis by Billings, 1 is nearer to R. abrupta of the Delthyris Shaly limestone series than to the side forms R. vent/ricosa and 

R. nobilis, which are the dominant types of the-Upper Pentamerus. 

In plications and form the Square Lake forms are thus nearer the R. 

mutdbilis stage of evolution. The state of mutation may be expressed 

by saying that the mature stage of R. mutabilis dominates the first 

half of the development of R. mainensis, whereas it dominates but a 

quarter of the R. dbrupta form; and in the second half of growth of 

R. mainensis we have represented the three-quarters adult growth of 

R. abrupta. The result, in form, is a greater convexity of the beak 

part, with broadening of the median area, whereas the dominant characteristic of R. abrupta is the square-built form of the main body, with 

only moderately gibbous umbonal region. The gibbous form of the 

Delthyris Shaly limestone, R. nudeolata, shows its advance upon 

R. mutabilis by its fewer ribs at a corresponding stage of growth and 

size, and, when compared with R. mutdbilis, shows an acceleration of 

the lateral superficial over the forward growth.

1 See PI. II, figs. 11,14,17, which is the typical form of R mainensis Bill., and PI. 1, figs. 9-24, and 

PI. II, figs. 2, 5, 8,11,14,17.
tS CONTKIBUTIOFS TO THE GEOLOGY OF MAINE. [BULL. 165.

These species are taken as they are defined, without attempt to pass 

judgment as to the propriety of drawing the specific lines as they are 

represented. The attempt to closely correlate the specimens with some 

particular species diverts the attention from the evolutional laws which 

the evidence contains and illustrates.

In the above discussion attention is directed to the variations and the 

differences which are expressed in the-dominant characters, or what 

might be called the habit or fashion characteristic of the whole group 

of rhynchonellas living at each successive stage. And it is the study 

of these peculiarities in the prevailing characteristics of a group of 

forms whose likeness suggests genetic affinity that promises to give 

us the means of detecting, in the fossils themselves, their position in 

the evolution of the race.

For this purpose, of course, it is necessary to have before us a sufficiently full representation of the group of species to show what are 

the dominant species of the fauna.

This study of a single group of species has demonstrated the fact 

that the evolutional stage of the group is indicated with precision, 

independent of the names of species, and independent of the fact that 

the specimens actually present in the Maine fauna agree precisely in 

scarcely a single case with those of any fauna of New York.

From this study it is evident that the Square Lake fauna is taxonomically the equivalent of the Delthyris Shaly limestone fauna of New 

York. The other, species in the fauna bear out the same conclusion, 

both by the absence.of species.of. lower and higher stages and by the 

presence of characteristic forms. The.habit of the species of this 

group of rhynchonellids also suggests closer relationship to stages 

earlier than the Delthyris Shaly limestone of the "New York section 

than to later stages.

The satisfaction attained by this method of correlation is the excuse 

for presenting it in this imperfect 'manner at the present time. Its 

elaboration and full presentation is reserved for future publication.

CHAPMAN SANDSTONE.

Presque Isle Brook.-^-The typical exposure of the Chapman sandstone 

is along the east (right) bank of the south branch of Presque Isle Brook, 

about a mile from the south line of Chapman Township and about a 

mile west of Tweedy's, on the road running southwest from Presque Isle.

The fossils and the locality were first brought to the writer's notice 

by Olaf 0.' Nylander, of Caribou, from whom the fossils were purchased 

fbf'ifc'he Survey. In 1897 the locality was visited by the writer. More 

fossils were collected, and the character of the formation was observed. 

The station number'is '1099 A.' The rocks are mainly thick-bedded 

sandstones, with some shaly layers, and are exposed for a quarter mile
WILLIAMS.] FAUNA OF THE CHAPMAN SANDSTONE. 79

or so along the bank of the stream. The general direction of the dip 

is northwest N. from 30° to 45° W. It was estimated that the thickness of the deposits in sight is at least 500 feet. The fossils are in the 

more shaly and thinner-bedded layers near the top of the exposure, 

between heavy-bedded sandstones, which in some cases show traces of 

plants, but generally are barren. Fossils occur in the more arenaceous 

beds, as is shown by their discovery in loose blocks in the neighborhood, 

but such fossiliferous sandstones were not discovered in place.

Fauna of 1099 A.

\. Rensselseria (Beachia) n. sp. cf. B. 

suessana.

2. Holopea cf. Danai.

3. Loxonema cf. planogyrata.

4. Pleuroclictyurn sp.

5. Spirifer gaspensis.

6. Ortbonota n. sp. (cf. undulata).

7. Palssoneilo cf. constricta.

8. Palseoneilo cf. plana.

9. Palseoneilo cf. maxima.

10. Palseoneilo, five or six new species.

11. Sanguinolites n. sp. (cf. claviilus).

12. Leiopteria, six species.

13. Pterinea rectangularis cf. flabellum.

14. Pterinea, three species.

15. Cf. Glyptodesma sp.

16. Cypricardella cf. gregarius.

17. Nucula (n. sp.).

18. Beyrichia tuberculata Kloden.

19. Psilophyton princeps.

20. Stem large plant.

Ednnunds Hill. In the northern part of Chapman Township, just 

south of the northern boundary, the Chapman sandstone is exposed in 

the lower part of Edmunds Hill (1099 C). * The whole base of the hill 

appears to be of sandstone and the cap is of igneous rock. The sandstone at this point is brownish to gray in color, from very fine to 

medium grained, and from shaly, thin layers to massive and thick 

bedded. Some of the same species are found at this and the more 

southern locality, while some species collected at Edmunds Hill have 

not been seen elsewhere.

Fauna of 1099 C.

1. Rensselseria (Beachia) n. sp. cf. B. 

suessana.

2. Spirifei; arrectus cf. " cyclopterus" 

Billings.

3. Spirifer cf. concinnus.

4. Homalonotus cf. vanuxemi.

5. Chonetes nova-scotica Hall (cf. sarcinulatus var. plana Schnur).

6. Chonetes canadensis Bill. (cf. lepteena 

lata Sow.).

7. Bellerophon, two species.

8. Holopea sp. :

9. Several gastropods.

10. Avicula cf. textilis.

11. Lam el lebranchs, several genera arid 

species.

12. .OrtKoceras, a fragment.

13. Tentaculites. ' ,

14. Beyrichia tuberculata Kloden.

15. Plant fragments.

Presgue Isle and Mcvrs Hill. In addition to the above, several loose 

blocks were found along the roads in Presque Isle and Chapman, and 

one at the foot of Mars Hill, which have been marked 1099 B 1, 2, 3, 

4, and 5. These contain the following species:
80 CONTRIBUTIONS TO THE GEOLOGY OF MAINE. [BULL. 165. 

Fauna of 1099 B 1, 2, 3, 4, and 5.

1. Rensselteria (Beachia) n. sp. cf. suessana.

2. Spirifer raricostus Billings.

3. Spirifers of the arrectus and gaspensis 

form.

4. Avicula cf. securiformis.

5. Chonetes canadensis.

6. Bellerophon.

This fauna indicates a horizon nearly equivalent to the early stage 

of the Gaspe sandstone, which the Canadian geologists have correlated 

with the Oriskany. It is undoubtedly Eodevonian,. and differs from 

the typical, more western, Oriskany fauna in the general facies of the 

species.

The abundant and great development of the Rensselwria is a notable 

feature of the fauna. The specimens are provisionally referred to 

It. siiessana, which they most nearly approach among the American 

forms in generic characters. Comparisons with the figures of Terebratula strigiceps, referred by Keyser and others to Rensselseria, as well 

as study of the faunal associates, lead the writer to the opinion that 

the Maine specimens may be identical with the European form. The 

name Rensselwria mainensis is provisionally proposed for this form.

This species is not reported from the Lower Helderberg,. and is, so 

far as the reports of its range are known, indicative of the Lower 

Oriskany. As is noted in the account of the Moose River sandstone 

fauna, this same species occurs in western Maine. The association of 

species there found corresponds more closely with the fauna of No. 8 

of the Gaspe Jimestone series of the Canadian reports. The spirif ers 

common are the forms called by Billings Spirif&ra raricosta and 

Spvriferu cydoptera. This Moose River sandstone fauna, as stated on 

page 88, has been called Oriskany by Hitchcock, and the corresponding 

fauna of Limestone No. 8 and of the base of the sandstone of the Gaspe 

series is also called Oriskany by Billings.

Both these faunas and the Chapman sandstone faunas belong more 

nearly with the Lower Oriskany of Becraft and the southern Appalachians than with the fully developed Oriskany fauna of New York.

After the manuscript of this bulletin was finished and handed in to 

the Survey the author continued his investigation of the Chapman 

sandstone fauna, with the result of determining its correlation with 

the ("Tilestone") Downtonian fauna of the Welsh standard Silurian. 

The importance of this identification to a correct understanding of the 

Maine Paleozoics furnishes sufficient reason for the insertion at this 

place of the more significant parts of the paper in which the results 

were first announced. 1

The identification of the Chapman sandstone fauna of Aroostook 

County, Maine, with the typical Ludlow "Tilestone" fauna of Mur1 The Silurian-Devonian boundary in North America; I, The Chapman Sandstone fauna: by Henry 

S. Williams: Am. Jour. Sci., March, 1900, 4th series, Vol. IX, pp. 203-213.
WILLIAMS.! THE HEECYNIAN FAUNAS. 81

chison furnishes important new evidence bearing upon the question of 

the exact boundary between the Silurian and Deyonian systems in 

North America.

The discussion of the Hercynian problem has resulted in the placing, 

by several of the best continental European paleontologists, of the 

Silurian-Devonian boundary below the Hercynian fauna. Kayser, 1 

followed by others, has adopted the opinion that the American equivalent of the Hercynian fauna is to be found in the Lower Helderberg.

Dr. J. B. Clark and Mr. Schuchert2 have attempted to prove, on 

paleontologic grounds, that the Lower Helderberg fauna has a Devonian "aspect," and, trusting to their theories, have proposed to classify 

the formations containing the typical Lower Helderberg faunas in the 

Devonian system. 3

When Professor Kayser's paper first appeared the writer was struck 

with the force of his paleontologic argument for classifying the Lower 

Helderberg and Hercynian faunas together, but was not then satisfied 

with the proof of the Devonian age of all the faunas so classified. 

When Dr. Barrois's paper on the Erbray faunas appeared, 4 it was 

gratifying to**find confirmation of this opinion.

t)r. Freck's papers 5 were also emphatic in claiming a Devonian age 

for the Hercynian, and the combined evidence of these gentlemen (and 

others taking part in the discussion) pointed very strongly to the 

conclusion that we must drop our Silurian-Devonian boundary below 

the main part of the Lower Helderberg if we would adopt European 

(continental) usage.

The similarity of the Gaspe section to the typical Welsh sections of 

the Silurian system, running up to the base of the Old Red sandstone, 

gave me hopes that a study of the sections in northern Maine might 

reveal some faunas representing the upper part of the Silurian more 

closely than do the faunas of New York. As the fossils of Maine 

were studied a transition fauna was found which throws considerable 

light upon the exact position of the boundary plane between the two 

systems,'Silurian and Devonian, in our North American rocks.

The fauna referred to is in the Chapman sandstone. A preliminary 

examination of it has revealed' its close correlation with the Ludlow 

Tilestone fauna of Murchison, and its still closer relation to the Upper

!Die Fauna der iiltesten Devon-Ablagerungen des Harzes: Abhand. geol. Specialkarte Preussen, 

etc., Vol. II, Ft. IV, 1878, pp. 284-285.

2 The nomenclature of the New York series of geological formations: Science, Dec. 15. 1899, new 

series, Vol. X, pp. 874-878.

3 See paper read at the Geol. Soc. America, Washington, December, 1899.

4 Fauna du Calcaire D'Erbray, by Charles Barrois: M6m. de la Soc. g6ol. du Nord, Vol. HI, April, 

1889.

5 Ueber das rheinische Unterdevon und die Stellung des " Hercyn," by Fritz Freck: Zeitschr. 

Deufech. geol. Gesell., Jahrg. 1889, pp. 175-287, etc.

Bull. 165 6
82 CONTRIBUTIONS TO THE GEOLOGY OF MAINE. [BUM, 165.

Arisaig fauna, D of Honeyman's section, which was "unhesitatingly 

referred to the Ludlow Tilestone" by Salter in 1862. *

This Chapman sandstone fauna is the latest marine Paleozoic fauna 

so far recognized in Maine, unless the Moose River fauna with Oriskany species be a little later. It is contained in a massive brown sandstone and argillaceous,layers stratified therewith. Its comparison with 

other faunas links it with the so-called Oriskany of the Moose River 

region farther west, and also with the early beds of the Gaspe" sandstone farther east. For this general region it .is a representative of 

the transition zone from calcareous formations, which are unmistakably Lower Helderberg in age, up to coarse gray and red sandstones 

containing Devonian plants, reported to be 7,000 feet thick on the 

Gaspe" Peninsula and to represent the Old Red sandstone phase of the. 

Devonian system.

The fauna contains some twenty-five or thirty good species, a few 

of which can be identified with species of the Tilestone and Upper 

Arisaig faunas already described. A few Gaspe" species described by 

Billings are closely approached; but, as a fauna, the resemblance to 

the typical Tilestone species of Murchison's Silurian -system is most 

striking and suggestive.

The faunas, 1099 A, B, and C, are given on previous pages (see 

pp. 79, 80).

The significance of the correlation of this Chapman sandstone with 

the Tilestone of Murchison is found in the fact that the Tilestone contains the topmost fauna of the original Silurian system of Murchison. 

This fauna was described by Sowerby in The Silurian System (1839), 

and afterwards the Tilestone was placed by Murchison himself in the 

Silurian (Siluria, 1854). This change was brought about by the 

recognition by Murchison that paleontologic evidence is of greater 

importance in the determination of the age of rocks than petrographic 

evidence. By the study of The Silurian System it is perfectly evident that the Silurian system was intended by Murchison to include all 

the fossiliferous formations lying below the Old Red sandstone. We 

find this indicated clearly on pages 3 and 4, and still more clearly 

expressed on page 7, of the introduction of The Silurian System, 

where are found the following words.(referring to the name Silurian): 

"The term was no sooner proposed than sanctioned by geologists, both 

at home and abroad, as involving no theory, and as simply expressing 

the fact that in the ' Silurian region' a complete succession of fossiliferous strata is interpolated between the Old Red sandstone and the 

oldest slaty rocks." We find that the reason for including the Tilestones in the Old Red was the fact that the soil weathered out reddish 

in the same way as the Old Red sandstone did where it was typically 

represented. These tilestones, however, were not always red in themi Quart. Jour. Geol. Soc., Vol. XX, 1864, p. 334
WILMAMS.] THE TILESTONE OF THE SILURIAN SYSTEM. 88

selves; but, on passing below, the typical Upper Ludlow weathered 

gray. This seems to have been the prime reason in the mind of Murchison for classing the Tilestbne with the Old Red. When, however, 

the first edition of Siluria was written, the fact that the species of 

this fauna were marine and not fresh-water types, and that some of 

them, were identical with species in the formation below (whkh he 

called Silurian), led Murchison to call this Tilestone the top member of 

the Silurian instead of the bottom of the Old Red. In Siluria appears 

a concise description of the transition from the Ludlow rocks into the 

Old Red sandstone, as seen in Carmarthenshire and Pembrokeshire: 

'' In all these places strata of dull greenish-gray argillaceous sandstone, 

minutely micaceous, differing chiefly from the type of the Ludlow 

of Shropshire in being harder and thicker bedded, and which repose 

on rocks with Upper Silurian fossils, plunge under red and green strata 

(the red rabof Pembroke), or bottom beds of the Old Red sandstone" 

(p. 141). ,

The typical localities from which the Tilestone fossils came are 

Felmdre, on the Teme, and Horeb Chapel, in the valley of Cwm Dwr, 

between Trecastle and Llandovery, near Cwm Dwr. In The Silurian 

System the passage beds near Felindre are described as "hard, greenish, and reddish, highly micaceous sandstone, which contain the Leptcena lata and the Terebratula nucula of the Ludlow rock, together 

with casts of several shells identical with those found in the tilestones 

of the Cwm Dwr, Carmarthenshire, and which have never been found 

in the Silurian system below its junction with the Old Red sandstone" 

(p. 191).

The reason for placing the base of the Old Red sandstone above these 

tilestones is stated in the following passage in Siluria: "Even then, 

however, the fossils which were figured as characteristic of such tilestones exhibited little else, as I showed, than species common to the 

Ludlow rock itself. This zoological fact, and subsequent researches 

in other parts of England, above all those of Professor Sedgwick in 

Westmorland, where the Upper Ludlow strata are much developed, 

have for eleven years led me to classify these tilestones with the 

Silurian rocks, of which they form the natural summit. For, even in 

their range from Shropshire through Hereford and Radnorshire, into 

Brecon and Carmarthenshire, whether they are of red or yellow colors, 

they are charged with Orthoc&ras bullatum, Chonetes (L&ptcena) lata, 

Spvrifer elevatus, Orthis hvnata, Ithynchonella rmcula, Gucullella ovata, 

Bell&ropliontrilobatus, JB. expcmsus, Trochus helidtes, Holopella (Turritella) obsoleta, and the minute bivalved crustacean, Beyrichia tuherculata. All of these are the most common fossils of the Upper Ludlow 

rock; although a few of them descend as low as the Caradoc sandstone" (p. 139).
84 CONTEIBUTIONS TO THE GEOLOGY OF MAINE. [BULL. 165.

From these quotations it is evident that the Tilestone was regarded 

by Murchison as the upper member of the Silurian system as he defined 

it in 1854 and as it occurred in his typical sections.

The writer's attention was first attracted to the possible equivalency . 

of the Chapman sandstone and Tilestone of Murchison (= Downton 

sandstone and Ledbury shale) by noting thai Zeptcena lata of the-list in 

The Silurian System is a true chonetes and closely resembles some of 

the specimens from Chapman. On studying up the definitions and 

synonymy of the species, it became evident that Davidson, who identified Leptoma lata von Buch with Chonetes striatetta Dalman, in doing 

so was following DeKoninck. In quoting synonymy, however, he 

excludes Sowerby's fig. 13 of PL V, which, as figured, presents the 

'flatness characteristic of the species'occurring in the Chapman sandstone.

The chonetes (No. M 248) of the Chapman sandstone agree with 

Hall's C. nova-scotica 1 in size and form, and from descriptions it seems 

that the small specimens referred to C. canadensis by Billings, 2 having 

the proportions of G. melonica, are identical with Hall's species G. novascotica. There is also a specimen (No. M 250) (the writer originally 

referred it to Orthqthetes, the hinge and beak being absent) which 

upon examination is found to present the typical characters of Chonetes 

canadensis Bill., so far as they are visible. Dawson spates that "the 

new species Chonetes nova-scotica is very characteristic of the upper 

member" [of the Arisaig section]. 3 Hall compared the species with 

"(7. cornuta of the Clinton group of New York,"* but the Clinton 

species is much smaller than even the smallest specimens in the Chapman sandstone. Billings, in describing the chonetes of the Gaspe 

series, calls his more gibbous form Chonetes melonica, and he compares 

this with C. striatella of Dalman, but finds it distinct (p. 16). Clio-' 

netes canadensis Billings differs from the description of G. melonica in 

being nearly flat. Billings remarks, however, "Small specimens of 

this species [ G. canadensis] have nearly the proportion of C. melonica, 

but are always nearly flat, while those of the latter are always more 

convex" (p. 18). 2 From a study of the descriptions it is evident that 

these "small specimens," referred by Billings to his species C. canadensis, are identical with the form described by Hall as C. nova-scotica, 

thus linking together the chonetes of the transition beds of the Gaspe 

section, formation D of the Upper Arisaig of Nova Scotia, and the 

Chapman sandstone.

Although the writer finds no description of the specimens referred by 

Sowerby to the species Leptcena lata von Buch, the figure so labeled on 

PI. V certainly appears as if nearly flat. Even were this not the case 

(which an examination of the type specimens would demonstrate), the 

fact that we have in the Gaspe" series both fully gibbous and flat forms,

1 Canadian Nat. and Geol., Vol. V, p. 144, fig. 2. 3 Canadian Nat. and Geol., Vol. V, p. 137.

2 palaeozoic Fossils, Vol. II, Pt. I, p. 18. " Op. cit., p. 145.
WILLIAMS.] THE CHAEACTEEISTIC SPECIES. . 85

which closely resemble each otKer in other respects, gives reason for 

supposing that the British form is at least represented by these Gaspe" 

and Maine species.

In Hall's description of the Arisaig specimens of CJionetes novascotica it is stated: " A stronger and more elevated stria often marks 

the median line from beak to base of the ventral valve." 1- This feature 

is seen on several of the specimens of the Chapman sandstone, and, 

curiously, it is not always the central plication. In one case several 

plications, a little out of the center, are thus enlarged. Such a trick 

of variation would seem distinctly to indicate close phylogenetic 

relationship.

In the Oriskany of Albany "and Schoharie counties, in New York, a 

form (G. compla/imtus) quite as large as Billings's C. canadensis is 

described by Hall. The larger forms are all from the Ga'sp6, Maine, 

and Oriskany faunas at the summit of the Silurian. LeptCBna lata, 

which is figured as larger than the ordinary, types of Chonetes, is said 

to be " one of the most characteristic shells of the Upper Ludlow." 2

The bellerophons furnish a second set of diagnostic species. In the 

original "list of the Tilestone fauna four species of Bellerophon are 

named, viz, Bellerdphon carinatus, B. striatus, B. frilobatus, B. glolatus.

Bellerophon trilobatus is said to be a characteristic form of the Tilestone. 3 This species is represented in both the Chapman sandstone and 

formation D of Arisaig. In Siluria it is stated that " B. expansus, 

B. MurcMsonoe, B. carinatus, and B. trilobatus, generally of small 

size, are most abundant everywhere in the upper beds of the Ludlow 

rock" (p. 231). Bellerophon carinatus and B. trilobatus are both represented in the Chapman; and Honeyman reports all four species from 

the Upper Arisaig, Zone D.*

A third diagnostic form is called "Agnostus tuberculatus (Battus 

tuberculatus Kloden)" by Sowerby in 1839. 5 This is Beyrichia tube?*- 

culata Kloden. Several specimens of this species, or a very closely 

related form, are recognized in the Chapman fauna. Hall described, 

under the name Beyrichia pustulosa, a species from Zone D of the 

Arisaig, of which he says: "This species resembles very nearly the 

B. tuberculata of Kloden, as described and figured by Mr. T. Rupert 

Jones." 0 Of this form Murchison writes, in Siluria, as follows: "Of 

the latter genus the Upper Silurian species is B. tuberculata. It 

is very abundant from the Wenlock shale to the highest Ludlow

1 Descriptions of new species of fossils from the Silurian rocks of Nova Scotia, by James Hall: Canadian Nat. and Geol., Vol. V, p. 145.

2 Silurian System, p. C03. 

3 Op. cit.,p.l41. . 4 Quart. Jour. Geol. Soc., Vol. XX, p. 343.

5 Silurian System, p. 004, PI. Ill, fig. 17.

"See Jones's identification of this species in the Arisaig rocks, in Quart. Jour. Geol. Soc., Vol. XXVI, 

p.492.
86 CONTKIBUTIONS TO THE GEOLOGY OF MAINE. [BULL. 165.

stratum, and .is a good index of Upper Silurian rocks, though found 

sometimes in the upper division of the Caradoc" (p. 236).

In addition to these characteristic species of the Tilestone fauna in 

the Maine and Arisaig rocks, a majority of the forms described in 

Sowerby's original list of that fauna are represented by the same, or 

closely allied forms, in both the Chapman sandstone and Zone D (Honeyman), Arisaig, as will appear from the following table:

List of representative species of the Tilestone fauna in the Chapman sandstone, Maine, and

- TILESTONE.

1. Cypricardia cymbseforinis

2. Pullastra leevis

3. Cuculleea antiqua

4. C. ovata

5. C. cawdori

6. Area ?

7. Avicula rectangularis

8. Leptsena lata

9. Spirifer ptychodes 

(=S. elevata Dalman)

10. Orthis lunata

11. Terebratula macula 

(=Rhynchonella)

12. Lingula cornea

13. Natica glaucinoides

14. Trochus helicites

15. Turbo Williams!

16. Turritella obsoleta

17. T. gregaria

18. T. conica

19. Orthoceras semiparti- 

	tum

20. 0. ?

21. 0. striatuin

22. 0. tracheale

23. Bellerophon carinatus

24. B. striatus

25. B. trilobatus

26. B: globatus

27. Tentaculites scalaris?

28. Battus tuberculatus

Zone D, Arisaig, Nova Scotia.

CHAPMAN SANDSTONE. 

Goniophora cf. Hamil 

ionise

Cypricardella cf. gregarius

f Palaeoneilo cf. cuneatus 

- P. % cf. concentricus 

J P. cf. elongatus 

j P. cf. nuculiformis

P cf. subovatus 

I and others.

Pterinea rectangularis 

Chonetes nova scotica 

C. canadensis 

' Sp. arrectus var. 

Sp. concinnus 

Sp. cyclopterus Bill. 

Sp. raricosta Bill.

? 

not seen 

not seen 

?

Pleurotomaria sp. 

(M 227) 

Holopea cf. Danai

? 

Loxonema cf. planogyrata

A single fragment

B. carinatus 

B. trilobatus

B. cf. elongatus 

Bey rich i a tuberculta

ZONE D, ARISAIG. 

C. cymbseformis, cf. Nuculites (Orthonota) 

carinata Hall

not reported 

Cleidophorus cuneatus , C. concentricus 

C. erectus 

C. elongatus 

C. semiradiatus 

C. ~ nuculiformis 

C. subovatus

?cf. Avicula Honeymani 

C. nova-scotica H. 

C. tenuistriata 

Sp. rugsecostus 

Sp. subsulcatus

Rhynchonella (3 species)

Lingula sp. ( 

?

?

?

Murchisonia Arisaigensis 

?

M. aciculata 

0. punctostriatum

0. nummulara Sow.

0. ibex Sow.

0. exornaturu

B. carinatus

B. striatus

B. trilobatus

B. globatus

T. distans.

B. pustulosa Hall

B. equilatera
WILLIAMS.] THE EQUIVALENCY OF THE CHAPMAN FAUNA. 87

In addition to the above, Hoinalonotus knightii Konig is reported 

from the Upper Ludlow, and also from Zone D, Arisaig; and an undetermined representative of the same genus appears among the Chapman specimens.

The presence of plants is further significant. In the Chapman 

sandstone a specimen of Psilophyton, which is probably P. princeps, 

appears in the midst of the marine fossils, giving -evidence of proximity of land, and also of the transition condition leading up to the 

Old Red sandstone type of Devonian. "Psilophyton (?)" is also reported from the Upper Arisaig, 1 arid it is the "Tilestone" of Wales 

( Upper Ludlow and Downton sandstone) in which the earliest 

known traces of land plants appear in the Welsh succession: 2

The above evidence leads directly to the conclusion that the fauna 

of the Chapman sandstone of Maine is the equivalent of the Tilestone 

fauna of Wales and of the uppermost Arisaig fauna of Nova Scotia. 

The latter has already been authentically identified with the "Ludlow 

Tilestone" by Salter, and the general fauna of the Upper Arisaig has 

been identified with the Lower Helderberg by all those who have 

studied the species.,

The Nictaux iron-ore fossils indicate a somewhat younger fauna, 

which has been recognized by Dawson and other paleontologists as 

approximately equivalent to the Oriskany sandstone of the New York 

section.

In the Gasp6 series the place of transition from the Gasp6 limestones to the sandstones is very near to the horizon of the Oriskany 

sandstone farther west. The stratigraphic and petrographic evidence 

in the Maine series points to the equivalency of the Chapman sandstone with the base of the Gaspe* sandstone. The particular fauna of 

the Chapman sandstone is not known, at present, in the Gaspe* series. 

But if this correlation with the Gaspe* series be correct, the relations 

of the several known faunas of the Maine series are in complete harmony with the known succession of the. Gaspe* faunas, and with such 

an interpretation. In that case the Square Lake fauna of Maine 

would be equivalent to the fauna of the upper limestones in the Gaspe* 

limestone series, and thus correspond with the known sequence of 

faunas in the Arisaig series.

Reviewing the whole evidence, the Chapman fauna must be regarded 

as the equivalent of the topmost fauna of the typical Welch Silurian 

system ( Upper Ludlow, Tilestone of Murchison, or Downton and 

Ledbury formations of later authors). This places the Silurian-Devonian boundary for North America where it was determined to be by 

De Verneuil in 1847, 3 classifying the Lower Helderberg formation

1Ami, Catalogue of Silurian fossils from Arisaig, Nova Scotia: Nova Scotia Inst. Sci., 2d series, Vol. 

1,1892, p. 185.

2 H. B. Woodward, The Geology of England and Wales, 1887, pp. 104,105.

3 Note sur le parallelisme des d6pots paluozoiques de l'Am6rique septentrionale avec ceux de 

1'Europe: Bull. Soc. geol. de France, 2d series, Vol. IV.
88 CONTRIBUTIONS TO THE GEOLOGY OF MAINE. [BULL. 165.

in the Silurian system. The special Chapman fauna, the writer is 

at present inclined to think, is equivalent to the Lower Oriskany fauna, 

as recognized at Becraf ts, and farther south in Virginia and Tennessee; 

but however the precise correlation with the faunas of interior America 

may be settled, the place of the Chapman fauna above the general 

Lower Helderberg fauna is well established by the Gaspe" and Arisaig 

sections. ' 

NEW -HAVEN, CONN., December, 1899.

MAPLETON SANDSTONE.

This sandstone contains plant remains which have been submitted 

to Mr. David White, of the United States Geological Survey, for 

special study. Psilophyton prmceps is among the species seen, and 

the age of the sandstone is clearly Devonian. Psilophyton was also 

seen in the Chapman sandstones, with a marine fauna. These Mapleton 

sandstones are believed to be of more recent age than the Chapman 

rocks, but were probably continuous with them, and the two may represent the base and succeeding strata of the Gaspe" sandstone of Gaspe 

Peninsula.

Dr. Gregory has given an account, in his part of this report, of the 

petrographic, structural, and areal features of this sandstone (p. 136).

MOOSE RIVER SANDSTONE.

In Somerset County, northwestern Maine, there is a belt of sandstones and arenaceous shales, in some zones of which there is a fairly 

abundant fauna.

It is generally a tough, grayish sandstone with some argillaceous 

layers, weathering brownish from iron oxides, and of considerable 

thickness, running up into the hundreds and probably reaching several 

thousands of feet in thickness.

It was called "Oriskany sandstone," by C. H. Hitchcock, in the 

Report on the Agriculture and Geology of Maine, 1 and was described 

in the following terms: "Its most southwest locality is at Parlin Pond, 

then it is seen on Moosehead Lake, Chesuncook Lake, Telos and Webster lakes, and the Aroostook Eiver." 2 It is mapped as a belt, about 

the width of a township, extending from the fourth township west of 

Moosehead Lake, on the seventh range-(Bradstreet), thence running 

obliquely northeastward in a somewhat curving line toward Ashland, 

in Aroostook County. Billings, in the proceedings of the Portland 

Society, 3 defined the fauna at two points near Telos Lake.

In 1889 a series of collections from the region west of Moosehead 

Lake was made by Gilbert Van Ingen for the purpose of ascertaining

1 Agric. and Geol. of Maine, 2d series, 1861, p. 379; Geology of wild lands, map opposite p. 377.

2 Op. cit., p. 379.

3 Proc. Portland Soc. Nat. Hist., Vol. 1,1869, Pt. II, p. 10(1.
WILLIAMS.] FAUNA OF THE MOOSE EIVEK SANDSTONE. 89

the precise nature of the fauna. The collections so made were from the 

following localities:

Parlin Pond, Somerset County. 1059 C is a section beginning on 

Parlin Stream at the middle dam, where the stream runs for over a 

mile through sandstones and shales. Numerous fossils were obtained 

at various horizons in this section, marked C 1-12, and from loose 

bowlders, marked C w, x, y, and z.

As this and the next section contain a typical representation of the 

fauna, the detail of the rock sections is herewith given:

Section 1059 C.

Feet.

C 26. Bluish sandstone with quartz veins, barren........................... 25

25. A\rhite sandstone, soft, friable, 'barren ................................ 6

24. Blue sandstone with ? jasper ? pebbles, thinly laminated, barren....... 1

23. White sandstone, soft, friable, barren ................................ J

22. Blue sandstone, barren.............................................. 100

21. Shaly sandstone, barren............................................. 6

20. Fossiliferous shaly sandstone ........................................ £

19. Blue, very hard sandstone, barren................................... 6

18. Fossiliferous sandstone.............................................. 1

17. Bluish, very hard sandstone, barren ................................. 36

16. Thick bedded, barren............................................... 4

15. Thick bedded, fossils................................................. 7

14. Fossils..................................................... v ...... £

13. Barren..................................................... 1. ...... 13

12. Barren............................................................. 8

11. Shaly, very soft .................................................... 1

10. Barren............................................................. ?

9. Barren............................................................. 135

8. Fossils ................................./...-...-......-............ 7

7. Shaly............ ............................................... \

6. Barren............................................................. 2

5. Fossiliferous sandstone.............................................. 1

4. Barren............................................................. 6

3. Fossils............................................................. 2

2. Barren .............................................................. 7

1. Thin-bedded sandstone, fossils.>...................................... 24

Fauna of 1059 C.

C 20. Spirifer arrectus. 

C 7. 1. Discina cf. Crania bella. 

 2. Psilophyton. 

3. Plant fragments.

C 6. 1. Lissopleura'fequivalvis.

2. Plant stem.

C 1-3. Spirifer cf. cyclopterus. 

C 1-3. Stropheodonta blainvillii Bill.

The fuller faunas were obtained from loose blocks, more or less 

weathered, apparently from the neighboring ledges, viz: Cw, Cx , Cy, Cz .

Fauna of 1059 Cw.

1. Loxonema.

2. Stropheodonta cf. perplana.

3. Avicula.

4. Spirifer cyclopterus Billings.

5. Leptocoelia flabellites. "

6. Lissopleura sequivavis.

7. Cf. Conostrophia complanata.
90 CONTKIBUTIONS TO THE GEOLOGY OF MAINE. [BOLL. 165.

Fauna of 1059 C x. 

1. Lissoplenra.

Fauna of 1059 O.

1. Strophomena blainvillii Bill..

2. Chonostrophia complanata.

3. Nucula.

5. Of. Cryptonella eximia.

6. Loxonerna.

7. Cf. Platyceras.

4. Cf. Orthothetes.

Fauna of 1059 Cz.

^

1. Spirifer arrectus cf. cyclopterus Bill. '

2. Leptocoelia flabellites.

Jackman farm. 1059 D is a section on Canada road, in the town of 

'Jackman, 10 miles south of Moose River settlement and 5 miles north 

of Parlin Pond.

Bean Brook. 1059 D 1 is a section on the east side of the Canada 

road, at Bean Brook, 3 miles north of Paiiin Pond Hotel. A massive 

bed of sandstone of unknown thickness with fossils on some layers; 

the rock is very tough and gray in color; dip 18°, N. 70° E.

D x. A sandstone bowlder, with Orthoceratites.

D 2. Blue sandy shale, many fossils; dip 20°, N. 70° E.

D y. A bowlder with corals common.

D 3. Lowest outcrop of shale, fossils common.

D 4. Shale on farm, few fossils; dip 15°, N. 70 E.-

Fauna of 1059 D 1. 

1. Lissopleura sequivalis. 3. Tentaculites cf. elongatus.

2. Tentaculites. 4. Cf. Modiomorpha.

Fauna of 1059 D 2. 

1. Dalmanites anchiops.

Fauna of1059 D 9. 

1. Leptocoelia flabellites.

Long Pond: 1060 A, ledges at northwest end of Long Pond, forming islands in the lake:

" Feet. 

A 1. Hard fissile shale, unfossiliferous, dip NW ........................ about 50

A 2. The same rock, 200 yards northeast of A1 .....*................._........ -10

A 3. The same rock, 300 yards north of A 1.................................. 25

A 4. Ledge on north shore, Hugh Eedmond's farm, called by the lumberman 

"The Joe ledge," about one-fourth mile southeast of No. 3; dip 55°, 

N. 20° W ................................................ about 375

1060 B 4- A ledge on the south shore, 5i miles west of outlet; dip 

70°, S. 20° E., thickness 40 feet; thin layers contain fossils, otherwise 

barren sandstone.

Fauna of 1060 B 4.

1. Strophomena blainvillii Bill.

2. Cf. Megalanteris ovalis.

3. Avicula.
WILLIAMS.] THE BRASSUA LAKE FOSSILS. 91

Little Brassua Lake. Section 1061 A is on the south shore of Little 

Brassua Lake, along the line of the Canadian Pacific liailroad. The 

section begins at the milepost 237 and extends south about three-fourths 

of a mile along the track eastward. This station is in Sandwich Township, west of Big Brassua Lake.

Sec/.ion 1061 A.

Feet.

A 0. A heavy-bedded sandstone, barren, thickness unknown.

A 1. 120 feet east of A 0, barren, bluish gray on new surface, but weathers to gray. 15

A 2. Hard blue compact sandstone, weathering to Avhitish; dip 43°, N. 10° W.,

barren.....,........;.-............................................_ 15

A 3. 1,230 feet directly ESE. of A 2; more shaly than A 2; dip 62°, N. 10° W.;

28 feet from its lower surface fossils were found........................ 60

A 4. 1,140 feet east of nearer end of A 3; a hard, heavy-bedded sandstone, blue,

weathering to gray .................................................. 6

A 5. A bluish-brown, shaly sandstone, containing fossils...................... 8

A 6. Hard sandstone, with round vertical borings ............................ 8

A 7. Heavier-bedded sandstone, light blue-gray, barren....................... 13

A 8. Slaty, dark surfaces, laminated, barren............ i...................... 12

A 9. Blue-gray sandstone, like A 7, few fossils....... ^........................ 12

A 10. Blue, laminated, shaly sandstone, barren, like A 8........., ............ 5

A 11. Hard bluish gray, like A 9, barren..................................... 50

A 12. Laminated shaly sandstone, .with fossils................................ 10

Drift ............................................................... 3(5

A 13. Hard, heavy-bedded sandstone, barren ................................. 10

Chonetes antiope Bill.

1. Lingula sp. ?

2. Sphenotus sp.

Fauna of 1061 A 4.

Fauna, of 1061 A 5.

3. Modiomorpha sp. (also 1061 A 3).

4. Lingula artemis.

Stony Brook. Section 1061 B 1 is a hard, tough sandstone, shaly in 

some places, the greater number of the fossils being from the shaly 

part.

Fauna of 1061 B 1.

1. Spirifer gaspensis.

2. Spirifer gaspensis, large.

3. Chonetes antiopa Bill.

4. Chonetes cf. mucronata.

5. Strophomena blainvillii Bill.

6. Orthis cf. Lucia Bill.

7. Leptocrelia flabellites (? to this fauna).

8. Spirifer?

9. Avicula. .

10. ? Crinoid.

11. Zaphrentis cf. rugulata..

12. Amphegenia sp.

13. Loxonema sp.

14. Dalmanites sp.

15. Modiomorpha sp.

16. Spirifer cycloptera? Bill. pi. 3 A, fig. 

4c.

Big Brassua Lake. Several exposures were examined on the shores 

and islands of Big Brassua Lake (1062). The rocks presented the 

same general characters met in the sections farther west.
92 CONTRIBUTIONS TO THE GEOLOGY OF MAINE. [BOLL. 165.

Section 1062 A.

A; On west shore of lake, commencing with A 1, a low ledge on first point, about

one-half mile from inlet (Moose River). - A1. A rather solid shale, with very fine fossils; dip 25°, S. 80° E.

Brassua Stream. The following is a section at Brassua Stream:

Section 1062 B.

B1. A ledge under water, about 2 miles above the lake.

B 2. A ledge of shaly sandstone, forming a fall in stream, about 2£ miles above the

lake; dip 28°, N. 10° W. Two fossils (?) were found in it. 

B 3. The same rock, with same dip, exposed for 100 yards upstream. 

B 4. Same rocks, same dip, 1,000 yards farther (above B 3). 

B 5. Same, 200 feet farther.

B 6. Same rock, same dip, 300 feet farther. One fossil. 

B 7. 200 feet farther the same rock is exposed, but contains very many fossils. 

B 8. 150 feet farther, same rock, with a few fossils. 

B 9. 250 feet farther, same rock, no fossils. 

B 10. 200 feet farther, same rock, no fossils; dip 57°, N. 10° W.

Fossils were obtained from the following strata:

Fauna of 1068 A 1. 

# 

 1. Sp. cyclopterus (H) Bill.

2. Chonetes antiopa Bill. 

Fauna of 1062 B 2.

1. Orthothetes deformis.

2. Plant stem, (B3).

3. ? two lamellibranchs (? B 2).

Fauna of 1062 B 6. 

1. Orthothetes deformis H.

Fauna of1062 S 7.

1. Beachia suessana.

2. Orthothetes deformis.

3. Strophomena blainvillii.

4. Platyceras sp.

From 1068 OS. 

Plant stems.
CONTRIBUTIONS TO THE GEOLOGY OF MAINE

Part II. GEOLOGY OF THE AROOSTOOK VOLCANIC AREA

INCLUDING AN ACCOUNT OF THE CLASTIC ROCKS OF AROOSTOOK

COUNTY

BY

HERBERT E. GREGORY

93

CONTENTS OF PART II.

 Page.

9 CHAPTER I. Introduction.................................................. 101

Geography.. ...........\............................................. 101

Previous exploration ................................................. 102

CHAPTER II. Igneous rocks................................................ 105

Granites...................:......................................... 105

Mapletori granite-................ 1............................... 105

Drews Lake granite .............................................. 106

Khyolites............................................................ 107

Haystack rhyolite................................................ 107

Bhyolite of hills adjoining Haystack ..........'.................... 109

Trachytes............................................................ 109

Hedgehog trachyte. .'....................'..'............,........... 110

Chapman trachyte ............................................... 110

Woodland'trachyte............................................... 110

Quartz-trachytes..................................................... 110

Quoggy Joe quartz-trachyte....................................... Ill

Quartz-trachyte of Township 9, Eange 3............................ Ill

Andesites............................................................ Ill

Edmunds Hill andesites .............................'............. 112

Hobart Hill andesites............................................. 113

South Mapleton andesites.............:........................... 113

Castle Hill andesites............................................... 114

Diabase............................................................... 114

Aroostook Falls diabase. .......... ^............................... 115

Mars Hill diabase ....................'............................ 115

> Teschenites.......................................................... 116

CHAPTER III. Clastic rocks. .....................................^......... 118

Introduction and classification ........................................ 118

Volcanic tuffs...........................-.'........................... 119

Field description................................................. 119

Castle Hill tuffs............................................... 120

Normal type............................................. 120

Silicifiedtype ............................................ 121

Tuff in northeast part of Ashland Township.................... 121

Tuff on the Ashland-Sheridan road............................ 121

Petrography......................................'............... 122

Castle Hill tuffs.......,-.-..--------..-....-.-..---....-..... 122

Normal type............................................. 122

Analysis................................................. 124

Discussion of analysis .................................... 124

Silicified tuff of Castle Hill ............................... 124

Tuff in northeast part of Ashland Township.................... 125

Microscopic description................................... 125

Tuff on the Ashland-Sheridan road............................ 125

Microscopic description..................................... 126

95
96 CONTENTS OF PAET II.

CHAPTER III. Clastic rocks Continued. Page.

Volcanic sandstones and conglomerates .. ^............................. 126

' Field description................... 1............................. 127

Volcanic conglomerate on Welts Brook........................ 127

Volcanic conglomerates of Ashland Township.................. 127

Volcanic conglomerates of New Sweden Township.............. 127

Volcanic conglomerates of .Perham Township .........:........ 128

Volcanic conglomerates of Madawaska Lake..................... 128

Petrography ..........-........'............... .................... 128

Volcanic conglomerate on Welts Brook ........................ 128$

Volcanic conglomerates of Ashland Township....... .......... 129

Volcanic conglomerates of New Sweden Township.............. 129

Microscopic description................. T ................. 130 

Volcanic conglomerates of Perham Township .................. 130

Volcanic conglomerates of Madawaska Lake ................... 131

Sandstones and conglomerates......................................... 131

Sheridan sandstone............................... 1............... 132

Fine-grained variety...................................... 132

Coarse conglomerate variety ............................... 133

Chapman sandstone.............................................. 133

Mars Hill conglomerate............................................ 134

Rock structure........................................... 135

Mapleton sandstone .............................................. 136

Winslows Hill section .................................... 136

Petrography............................................. 137

Field relations ........................................... 137

Sandstones of other localities................i..................... 137

Calciferous quartzitic sandstone ................................... 138

Analysis................................................. 138

Limestones .......................................................... 139

Arenaceous limestones............................................ 140

Aroostook limestone.................................t............ 141

Previous study............................................ 141

Structure.....................................!.......... 142

Petrography...........................'.................. 142

Heavy beds of limestone ................................. 142

Fossiliferous limestone............................................ 143

Slates and schists..................................................... 143

Manganiferous iron slates............................................. 145

CHAPTER IV. Petrography of the igneous rocks............................. 146

Granites............................................................. 146

Mapleton granite................................................. 146

Dark aggregates in the Mapleton granite................... 148

Drews Lake granite .............................................. 148

Dikes of the granite areas......................................... 149

Aplite................................................... 149

Syenite .......................... ....................... . 149

Granite-porphyry........................................ 150

Kersantite ................................................ 151

Metamorphism caused by the granites and associated dikes.......... 151

Mapleton area............................................ 151

' Drews Lake area......................................... 152-

Rhyolites....---.-.............-.-.-.---.......-..................... 152
.CONTENTS OF PAET II. 97

CHAPTER IV. Petrography of the igneous rocks Continued Page.

Rhyolites Continued.

' Eock of the main mountain mass........................^. t ...... 153

Macroscopic description .................................. 153

Microscopic description................................... 153

Analysis.........................................'........ 155

White type...................................................... 156

Perlitic type ..................................................... 157

Macroscopic description .................................. 157

Microscopic description.................................... 157

Rhyolite breccia ................................................. 158

Macroscopic description ............................. '..... 158

Microscopic description................................... 159

Vesicular lava.................................................... 159

Macroscopic description .................................. 160

Microscopic description................................... 160

Trachytes............................................................ 161

Hedgehog trachyte..............--...--....--...-.-....--........ 161

Trachyte of Chapman Township................................... 162

/ Macroscopic description .................................. 162

Microscopic description................................... 162

Analysis.................................................. 163

Doubtful trachytes ................................................ 164

Quoggy Joe quartz:trachyte....................................... 164

Macroscopic description .................................. 164

I Microscopic description................................... 165

( Analysis................................................. 166

Discussion of analysis..................................... 166

Classification ............................................ 167

Quartz-trachyte of Township 9, Eange 3............................ 168

Andesites............................................................ 168

Augite-andesite .................................................. 169

Macroscopic description................................... 169

' Microscopic description................................... 169

Analysis......__....................................... 171

Hornblende-andesite ............................................. 172

' Microscopic description................................... 172

Southern Mapleton andesites...................................... 173

Castle Hill andesites.............................................. 174

Macroscopic description................................... 174

Microscopic description................................... 174

Andesite ash beds. ^............... 1.............................. 175

Diabase.............................................................. 175

' Aroostook Falls diabase........................................... 175

Analysis 1................................................ 176

Discussion of analysis..................................... 177

Mars Hill diabase ................................................ 177

Normal type...-...........'-.......................--........ 177

Microscopic description................................... 177

Glassy type.................................................. 178

Analysis................................................. 178

Discussion of analysis..................................... 179

Teschenites...........^............................................... 179

Field appearance................................ r ....... r ---,.. - 179

Bull. 165 7
98 CONTENTS OF PAKT II.-

CHAPTER IV. Petrography of the igneous rocks Continued. page. 

Teschenites Continued.

Coarse crystalline type............................................ 180

Macroscopic description................................... 180

Microscopic description................................... 180

Analysis................................................. 183

Discussion of analysis. .................. .j-................. 184

Granular type.................................................... 184

Macroscopic description................................... 184

Microscopic description...... ^............................ 185

Contact facies .................................................... 185

Macroscopic description................................... 185

Microscopic description................................... 185

CHAPTER V. General petrology .............................^............. 187
ILLUSTRATIONS IN PART II.

Pago 

PLATE III. A, Cleaved andesite, Edmunds Hill; B, HobartHill; massive andesite exposed by erosion......................................... 101

IV. Map of Aroostook volcanic area .................................. 105

V. A, Spherulitic rhyolite from Haystack Mountain; B, Vesicular lava

from Haystack Mountain ....................................... 107

VI. A, "Birch bark" weathering of rhyolite; B, Transverse section of

same ......... .................... .......................... 108

VII. A, Andesitic lava; B, Andesiticbreccia........ ................ 112

VIII. A, Fine-grained Sheridan sandstone; B, Sheridan sandstone........ 132

I.. A, Conglomerate of the Sheridan sandstone series; B, Sandstone from 

t. Madawaska Lake......-.----------.------..-.-... . .... 134

X. A, Kailroad cut at Houlton, showing.slated Aroostook limestone; 

B, Railroad cut at Timony road, showing folded and faulted 

Aroostook limestone........................................... 140

XI. A, Banded limestone; B, Aroostook limestone.................... 142

> XII. A, Mapleton conglomerate; B, Manganiferous iron slate ........... 144

) XIII. A, Perlitic type of rhyolite; B, Area between spherulites, perlitic 

i type of rhyolite ............................................... 158

XIV. ^4, Vesicular lava; J5, Volcanic tuff ................................ 160

FIG. 2. View of Haystack Mountain........................................ 107

3. Diagram of Haystack Mountain.................. %.................. 109

4. Section on Mapleton-Presque Isle road .............................. 113

5. Map of part of Mapleton Township, showing the teschenite area ...... 116

6. Map of Castle Hill area .._..............__.................... 120

7. Section at Mars Hill............................................... 135

8. Section through Winslows Hill..................................... 137

9. Microcline and orthoclase intergrowth .............................. 149

10. Zonal intergrowth of microcline and orthoclase...................... 150

11. Optical measurements of aplagioclase crystal........................ 182

U. S. GEOLOGICAL SURVEY

A. CLEAVED ANDESITE, EDMUNDS HILL.

H HOBART HILL; MASSIVE AK'DESITE EXPOSED BY EROSION.
CONTRIBUTIONS TO THE GEOLOGY OF MAINE.

PART 11, GEOLOGY OF THE AROOSTOOK VOLCANIC AREA,

By HERBERT E. GREGORY. ^

CHAPTER I. 

INTRODUCTION.

GEOGRAPHY.

The area considered in the present paper includes the section of 

Maine known as the "Aroostook country." An examination of the 

map, fig. 1 (p. 12), shows its location in the extreme northeast extension 

of United States territory.

The region is. without natural boundaries, and hence for purposes of 

this report the area is outlined and bounded as follows: On the east 

by New Brunswick; on the north by the St. John River and the Fish 

River Lakes; on the west by a line joining Portage Lake, Ashland, and 

Oakfield, and on the south by a line from Oakfield to Houlton. These 

lines include an area about 75 miles long by about 30 miles wide, which 

is separated from other parts of Maine by a belt of forest land, whose 

monotony is broken here and there by a few rich farms. The natural 

connection is with New Brunswick, and there is nothing in the topography or the character of the soil or the people to indicate when the 

boundary line has been passed. Much of the Aroostook country has 

been settled from the Maritime Provinces, and until a very few years 

ago the outlet for produce and the main line of travel was along the 

St. John River to the city of St. John, on the Bay of Fundy. The 

construction of the Bangor and Aroostook Railroad has largely 

changed this condition of affairs, but the region still reminds one of an 

agricultural island of great richness, reached from the southern part 

of Maine after traversing an uninhabited expanse of forest land.

The most thickly settled portion of northern Maine is the eastern 

border from Houlton north along the belt of-slated limestones (Aroostook limestones). In the vicinity of Houlton this strip is hardly more

101
102 CONTRIBUTIONS TO THE GEOLOGY OF MAINE*. [BULL. 165.

than 6 miles wide, but 30 miles farther north,,, in the valley of the 

Aroostook River, it widens to over 20 miles, and includes the prosperous townships of Fort Fairfield, Presque Isle, Mapleton, and part of 

Castle Hill, on the south side of the river, and Caribou, Woodland, 

and New Sweden on the north side. Farther up the Aroostook, about 

Ashland, is a limited amount of exceptionally fertile land.

The amount of settled country, however, is but a small part of northern Maine. West and north of Ashland there is a stretch of unbroken 

forest extending nearly to the St. Lawrence River, visited only by 

hunters and lumbermen, who use the rivers and lakes as highways. 

Within the area described in this report there are some twenty townships with no sign of human habitation except the winter log roads 

and occasional lumber camps. The change from well-cultivated fields 

to an uninhabited expanse of forest, "burnt land," and swamp is sudden and complete, as is well seen by ascending the highest points of 

the region. The pathless woods, with their soil thickly covered with 

products of forest decay, make the geologic investigation difficult, and 

render detailed mapping of extended sections impossible.

PREVIOUS EXPLORATION.

Geologic work in northed Maine has been carried on in the past by 

geologists employed by the State or by the Dominion of Canada. The 

first State survey was undertaken while yet the Aroostook lands 

belonged jointly to Maine and Massachusetts, and had in view the 

exploration of these lands preparatory to opening them to settlement. 

This first survey (now generally known as the Jackson survey) was 

instituted by an act of the State legislature passed on the 21st of 

March, 1836. 1 During the year 1836 a general topographic survey of 

the immediate vicinity of Houlton and of the St. John River from 

Woodstock to the mouth of the Madawaska was completed. In the 

following year Dr. Jackson, accompanied by Mr. Hodge, made the 

descent of the Aroostook River from La Pompique Stream to the St. 

John. The more important outcrops were located and briefly 

described, and the occurrence of iron ore in what is now Wade Plantation was dwelt upon at considerable length. 2 Exploration was not 

attempted except along the river. This report was written for the 

prospective settlers, and consequently the information as to trees, soils, 

and water supply is more complete and more valuable than the strictly 

geologic matter. The third and final annual report 3 of the Jackson

1 >Five thousand dollars was appropriated and Dr. Charles T. Jackson was placed in charge. Associated with him in the first year's work were Dr. T. Purrington, as agent on the part of Maine, and 

James T. Hodge, who represented Massachusetts. The survey was continued for three years, with 

different assistants and smaller appropriations each year.

2 Second Ann. Kept, on the Geology of the Public Lands belonging to the two States of Maine and 

Massachusetts, Augusta, Maine, 1838.

»Augusta, 1839.
GREGORY.] PEEVIOUS EXPLOEATION. 103

survey was transmitted to the legislature by Governor Fairfield on 

February 13, 1839. Besides the record of the work accomplished 

during the year 1839, this report contains a general summary of the 

results obtained by the survey during the three years of its existence. 

Considering the lack of accurate maps and the difficulties of travel, the 

work accomplished by Dr. Jackson was of a high order. It is to be 

regretted that all the specimens so carefully collected and labeled have 

disappeared, with the exception of the set presented to Bowdoin 

College. 1

Twenty-three years elapsed before the State undertook further 

geologic work. In 1861 a "scientific survey" of the State was 

organized. 2 Professor Hitchcock was appointed geologist and gave 

some portion of his time to investigations in the Aroostook Valley. 

In the Geology of the Wild Lands 3 he describes a section from 

Charlotte to Presque Isle and one from Penobscot Bay to Ashland, 

In the same volume Mr. Packard gives an account of his exploration 

of the Fish River Lakes, and of the route from Portage Lake through 

Ashland to Presque Isle. He also announced the discovery of the 

Square Lake fossil locality. During 1862 Dr. Holmes traversed the 

settled parts of Aroostook County, but added no geologic information of importance. While, the work was in this preliminary stage 

the legislature saw fit to cut off the ?~ -^priation, and the work which 

had been begun so well and which promised so much to science was 

brought to a close.

These two reports of Professor Hitchcock include what is known 

generally of the geology of Maine. The features occurring along the 

main traveled routes are briefly described, and the age and areal distribution of the different rock formations are worked out and represented upon a geologic map. The amount of work done in 1861 and 

1862 with so small an appropriation was highly creditable, and was so 

well done that the general interpretations then made are likely to stand 

the test of time. The permanent value of the second State survey 

would be greatly enhanced if the entire collection of minerals, rocks, 

and soils so carefully made had been preserved. 4

In 1885 Professor Hitchcock published a summary description of the 

geology of Maine, with a map in colors. 5 Some changes from the map

a Bayley and King: Catalog of the Maine Geological Collection, with a Brief Outline History of the 

two Surveys of the State, Waterville, Maine, 1890.

2 The scientific staff was Ezekiel Holmes, naturalist; Charles H. Hitchcock, geologist; George L. 

Goodale, botanist; J. C. Houghton, mineralogist; A. S. Packard, jr., entomologist; C. B. Fuller, marine 

zoologist.

3 Bound with Agriculture and Geology of Maine, 2d series, 1861.

 » Unfortunately the typical collection deposited in the statehouse was removed from its place and 

the specimens carelessly thrown into boxes, their labels often going into other boxes. As a result of 

Prof. W. S. Bayley's efforts, the remnant of this collection is now under the care of Colby University, at 

Waterville, Maine. The specimens have been identified as far as possible by the description giren in 

Jackson's reports, and a catalogue has been published (Bayley and King, footnote 1).

6 Geology of Northern New England, p. 1.
104 CONTEIBUTIONS TO THE GEOLOGY OF MAINE. [BULL. 165:

of 1861 were rendered necessary by new data furnished by the New 

Hampshire and New Brunswick surveys. This is the only complete 

geologic map of Maine that has been published.

As explained elsewhere, there is an intimate connection between the 

geology of Maine and that of New Brunswick and Quebec, and accordingly the investigations in the Canadian provinces have thrown considerable light on geologic problems in Maine. On the other hand, many 

facts are better exhibited in Maine, and the New Brunswick survey has 

found it advisable to conduct some field operations along the Aroostook 

River and the Fish River Lakes. 1 Prof. L. W. Bailey has had many 

years' experience in dealing with the complicated problem presented 

by the New Brunswick formations, and has given the benefit of this 

experience in his discussion of the similar geologic conditions of Maine.

The above-mentioned papers comprise all the material directly relating to the geology of northeast Maine. Much more work has been 

done on the coast line and many contributions of value have been 

made, especially in regard to the surface geology and the petrography 

of those parts which have been mapped. 2 At present the relation 

between the geology of southern and northern Maine has not been 

determined, and these parts of the State must be treated as two distinct 

areas.

1 The results of these excursions are given in the Transactions of the Royal Society of Canada and 

in the Reports of the Geological Survey of Canada. Three papers in particular, from the pen of Prof. 

L. W. Bailey, are of great value for the interpretation of the stratigraphy of the region, viz:

On the Silurian system'of northern Maine, New Brunswick and Quebec: Trans. Roy. Soc. Canada, 

Vol. IV, 1887, Sec. IV, pp. 35-41.

Notes on the physiography and geology of Aroostook County, Maine: Trans. Roy. Soc. Canada, 

Vol. V, 1888, Sec. IV, pp. 39-44.

On some relations between the geology of eastern Maine and New Brunswick: Trans. Roy. Soc. 

Canada, Vol. VII, 1890, Sec. IV, pp. 57-68. - '

The substance of these papers may be found also in Reports of Geological Survey, Canada, 1886-1893.

2 The papers of recent years, especially those of Staler, Davis, Crosby, Stone, Dodge and Beecher, 

Kemp, Bayley, and Smith are especially valuable.
U.S.GEOLOGICAL SURVEY BULLETIN NO. i65 PL. IV

A.HoenA Co-Liftl-B
CHAPTER II. 

IGNEOUS BOCKS.

Northeastern Maine is essentially a region of sedimentary rocks, 

among which igneous outcrops occur to a relatively small extent. 

The most numerous exposures of igneous rocks are located in Castle 

Hill and Mapleton townships, where they form the prominent topographic features (see map, PL IV). Even here, however, their 

extent is quite limited. It is an interesting fact that, although the 

distribution is so limited, the number of well-defined igneous types 

is large and shows wide variation in character.

It is the purpose of this chapter to discuss the general structure, 

nature, and field relations of the igneous rocks of this region, and to 

leave the microscopic and chemical descriptions to the succeeding 

chapter. A third chapter will briefly treat of the general petrographic questions presented by a study of this area.

The igneous rocks occurring in northeastern Maine will be described 

under the following heads: Granites, Rhyelites, Trachytes, Andesites, 

Diabase, Teschenites.

GRANITES.

Granite occurs in two small areas within the region described in this 

report. One is in the northeast corner of Mapleton Township, near 

the Aroostook River; the other is near Drews Lake. Neither exposure 

is topographically conspicuous, and it is not surprising that one of 

them has heretofore escaped notice. From the general character of 

the region a wider distribution of granite rocks was to be expected.

MAPLETON GRANITE.

The Mapleton granite (locally known as Munson's granite) forms 

part of a low, rounded hill, which has suffered so much erosion that no 

sharply defined ledges remain. The top of the hill is a tablelike mass 

covering some 6 or 7 acres, and bounded on the east, where it nears 

the calcareous slates, by a low cliff. The north side gives the best outcrops, and the slope is covered with slabs of granite which have been 

loosened above by the frost. The rocks on "the west and south sides 

of the hill are completely obscured by products of forest decay. The 

granite, as shown by its outcrops, forms an oblong mass, with northeastsouthwest axis, about 1 mile long and one-fourth mile wide. It has 

probabh' a somewhat greater extent, however, as shown by the fact 

that wheie the sedimentaries first appear to the west about one-eighth

105
106 CONTRIBUTIONS TO THE GEOLOGY OF MAINE. [BULL. 165.

mile distant the contact metamorphism indicates nearness to. the 

igneous mass.

The granite itself is not uniform in appearance. In parts of the 

field it is almost black; in others it is of a light color. The dark and 

the light areas are not confined to any particular locality, and the 

transition from one to the other may occur within a few inches or 

may be imperceptible for rods. The light parts may contain areas 

and streams of the dark, or the dark parts be smeared and banded 

with the light, without any apparent regularity as to size or shape. 

It is similar to the appearance produced by the presence of dark 

aggregates in granites, but is on a larger scale.

The field relations indicate that this is an intruded mass. No contact was seen, but the sedimentary rocks near by are metamorphosed 

in proportion as they approach the granite, there are no lavas or 

other extrusive materials found within miles of this outcrop, although 

they are abundant in the region. The granite is a small area surrounded by sedimentarjr rocks, and seems to have been recently 

uncovered by the great general denudation which northern Maine 

has suffered.

In the bed of the Aroostook River, at the base of the granite hill, 

are dikes of aplite, syenite,-and kersantite, which vary in width from 

a few inches to 500 feet. They have been intruded between the sedimentaiy strata, which are altered in consequence. As to their origin 

and time of formation, these dike rocks are referred to the granite 

mass.

DREWS LAKE GRANITE.

The granite of Drews Lake forms a somewhat conspicuous feature of 

the landscape. The country here is a low, rolling, wooded plain with 

many swamps, and the granite constitutes part of a group of hills and 

low knobs standing out in contrast to the general level. In the depressions between the hills is a group of lakes which constitute the head 

waters of branches of the Mattawamkeag, which 'flows southwesterly to 

the Penobscot, and of the Meduxnekeag, which empties into the St. 

John. The shores and bottoms of these lakes :this whole region, in 

fact, is strewn with large, angular, granite bowlders. The eminences 

here are in some cases granite; in others, highly metamorphosed schists 

and altered slates. The schists seem to be remnants of the ancient surface rocks, which in part have been wholly worn away, but in places 

still cover the granites. The granite hills are generally rounded, but 

in places present craggy, jagged profiles. Hitchcock 1 has mentioned 

this area and roughly outlined it on his geologic map. He considers 

it, together with several exposures to the southwest, to be part of one 

large mass typically exposed at Island Falls. This relationship is not 

indicated by the mass under discussion, which is not large and is nearly

1 Agriculture and Geology of Maine, 1862, p. 360.
U.S.GEOLOGICAL SURVEY BULLETIN NO. 165 PL.V

(A)

(A) SPHERULITIC RHYOLITE.

(B) VESICULAR LAVA.

THE HELIOTYPE PRINTING CO., BOSTON.
GREGORY.] EHYOLITES. 107

eveiywhere flanked by altered sedimentaries. The contact metamorphism and the relative position of the surrounding rocks are evidence 

that here, as in Mapleton, we have a locally intruded mass.

Dikes of aplite and granite-porphyry connected with the main mass 

are well exposed in the railroad cuts at the north base of the hilly district. Some are minute streaks; some are 40 to 50 feet wide. They 

are seldom straight and with even borders for any distance, but branch 

and fork, or even form a rude network. These dikes exhibit some 

interesting features'which will be considered under another heading.

This granite is a valuable resource for Aroostook County, and the 

quarry opened a few years ago at Ludlowis already furnishing considerable stone, especially for engineering purposes.

FIG. 2. View of Haystack Mountain; looking northwest.

RHYOLITES. 

HAYSTACK. EHYOLITE.

There is a prominent ridge of land extending north and south through 

the center of Castle Hill Township from the Aroostook River to near 

the head of Squawpan Lake. The State road crosses it a little to the 

west of the Castle Hill Hotel, and the Haystack road crosses it at the 

Halfway House. This ridge is formed of extrusive volcanic material, 

the north end being formed of the andesites grouped about Castle Hill 

and the south end of the rhyolites which have Haystack as their center. 

This mountain is the most prominent topographic feature of the Presque 

Isle-Ashland area, in which it. is unique as to form and position (see 

fig. 2). It rises abruptly from the, general plain to a height of about
108 CONTRIBUTIONS TO THE GEOLOGY OF MAINE.

600 feet, with an average slope of about 50°. The last 100 feet is very 

steep, and the whole appearance leads one to recognize the appropriateness of the name by which it has long been known. The base of 

the main mass covers scarcely more than one-fourth of a square mile, 

but connected directly with iifis a narrow ridge of the same volcanic 

material extending about three-fourths of a mile to the northwest. 

The easiest ascent is on the north side, where, on account of the connected ridge, the slope is scarcely over 30° until the top is neared. The 

east and the west sides are very precipitous. The talus on the slopes 

is abundant and is, in general, made up of small angular fragments, 

although on the west side there is a confused mass of giant blocks so 

piled as to leave large, roomy spaces between and underneath, which 

are locally called caves. Higher on the slope these detached pieces 

are more and more in place, until near the top blocks weighing 40 tons 

and more are found separated from the main mass by deep cracks a 

few inches wide and are ready to be pried off by the frosts of winter. 

The top of the hill is an uneven surface covering less than one-fourth 

of an acre, and an examination of the rock there exposed reveals the 

presence of a complicated system of intersecting cleavage cracks which 

has determined the form and size of the loose blocks on the slope. As 

one walks about the base of Haystack or climbs to the top, attention 

is attracted by the varied appearance of the materials composing the 

mass. On the top, only the dense bluish-white felsitic rock appears. 

Halfway down the slope the surface exposures have the peculiar birchbark appearance which characterizes parts of the white rhyolite. At 

the southeast base of the hill occur little-knobs which are formed of a 

dark breccia with jasperlike fragments embedded. Near by is the 

variety of rhyolite made up of little spherules; and finally, about onehalf mile east of the hill, there is a well-marked vesicular lava. A

detailed description of these various forms of .rocks will be found in 

the chapter on petrography (pp. 146-186).

From the field relations alone it is no easy matter to determine the 

character of this igneous mass. Only the top part is free from trees, 

underbrush, and moss, which conceal the rocks and make traveling 

difficult. The talus covering is very deep and widespread, and the 

drift has been so deposited as to conceal the contacts. Consequently 

the exact relation between the igneous and sedimentary rocks is not 

known! There does not seem to be much metamorphism except in 

places to the east of the mountain. The character of the rocks, however, is conclusive, for thejr are undoubtedly flows of lava, and indicate 

by their amygdaloidal structure nearness to the surface of flow. The 

probable field relation is indicated diagrammatically by the accompanying cut (fig. 3).

The whole mass has either been formed by some very recent extrusion or is the remnant of more extensive flows which have been long
U.S.GEOLOGICAL SURVEY BULLETIN NO. 165 PL. VI

"BIRCH BARK"WEATHERING OF RHYOLITE. 

TRANSVERSE SECTION.

THE HELIOTYPE PRINTING CO.. BOSTON.
GEEGORY.] TEAOHYTES. 109

buried and only recently brought to light by denudation. This question will be discussed in connection with the geologic history of the 

region.

EHTOLITES OF THE HILLS ADJOINING HAYflTACK.

The rock forming the hills immediately north of Haystack is in 

general closely similar both in general aspect and in microscopic structure to that forming the main mass. The hill on lot 115 is composed 

of rock almost identical with Haystack in structure, but appears to 

have suffered some brecciation and occasionally contains fragments of 

foreign material. The rock forming Pyles Hill conforms well with 

the typical rhyolites, and, because of the amount contained in the hill 

and the unaltered condition, might well have been described as the 

type, with Haystack proper as an additional occurrence. About the 

center of the west line of lot 115 the rhyolite exposed is of a white or

Slates. 

FIG. 3. Diagram of Haystack Mountain.

flesh color, and a microscopic examination shows it to be a sort of 

transition form between the true rhyolites and the quartz-trachyte of 

Quoggy Joe Mountain. To the west of Haystack, along the branches 

of Welts Brook, the rhyolite rocks have been cleaved and broken and 

afterwards recemeifled, so as to present the appearance of a coarse 

breccia. In one place along the south line of lot 100 an extensive 

'exposure of coarse volcanic ash was discovered, which will be described 

on page 127. A careful determination of the details of the rock formation about Haystack is impossible until land is cleared and the 

swamps are drained.

TRACHYTES.

Trachytes were found in three different localities in Aroostook 

County. One mass constitutes Hedgehog Mountain, another is found 

in Chapman Township, and a third area of doubtful trachytes forms 

low hills along a branch of the Caribou Stream in Woodland Township.
110 CONTKIBUTIONS TO THE GEOLOGY OF MAINE. [BOLL. 165. 

HEDGEHOG TRACHYTE.

Hedgehog Mountain is probably the largest single mountain mass in 

eastern Aroostook County. It is a ridge extending some 4 to 5 miles 

in a northeast-southwest direction and rising about 1,000 feet above 

the stream beds at-its base. It is surrounded by lakes and swamps, 

except on the northeast, in which direction it extends for a mile or 

two as a flat-topped hill. The mountain is thickly overgrown with 

trees and brush, and this, together with the great depth of the talus, 

makes an examination of the structure and rock formation impossible 

except at the very highest points, where the cliffs are exposed, and the 

continual splitting off of the blocks on the east and west sides of the 

mountain has left a bare, jagged ridge, in places scarcely 100 feet wide. 

The whole mass is separated into great blocks by two prominent 

cleavage planes, one of which strikes N. 80° W., the other N. 20° E. 

The blocks themselves in the ledge and on the talus slope suggest an 

indurated f eldspathic lava. When the region about this mountain can be 

more fully explored interesting relationships will doubtless be brought 

out, but at present it is advisable to limit the discussion) to a description of the occurrence and character of the rock composing the mass.

CHAPMAN TEACHYTE.

The Chapman trachyte occurs in the northwest corner of the township, on the north-south road near the west township line, where outcrops were seen on a hill about 1 mile south of the Presque Isle River. 

All the region south, east, and west of the river is forest and swamp 

land, with the exception of a few cleared farms along the road. It is 

on one of these farms that the trachyte occurs, close by the house and 

in the adjoining field. The outcrop occurs as rough ledges and jointed 

tabular rocks, rising but a few feet above the general level of the field, 

and in all cases is quite limited in extent. The several exposures seen 

indicate an area of about 5 acres, but it is likely that further examination, especially after the land is cleared, will show that the mass 

covers several square miles and may be connected with the little-known 

Hedgehog Mountain to the west. At present, ho;wever, the- swamps 

and products of forest decay effectually conceal the rocks, and nothing 

more definite can be said as to its relations to the other formations of 

the region.

WOODLAND TRACHYTE.

The outcrops of trachyte at this locality have been too little studied 

to warrant an extended description.

QUARTZ-TRACHYTES.

Quartz-trachyte will be described from two localities in the region 

included in this report. It forms the group of hills west of Fort Fair-
GREGORY.] QUAKTZ-TKACHYTES. Ill

field Junction called Quoggy Joe, and it also occurs as a dike outcropping on the south branch of the Presque Isle River about the middle 

of T. 9, R. 3.

QUOGGY JOE QUAKTZ-TRACHYTE.

Quoggy Joe is the prominent member of a group of hills with outlying knobs that form part of the divide between the Presque Isle 

and Meduxnekeag rivers. The ridge extends several miles in a northeast-southwest direction. Beginning on the north with low knobs, it 

rises to a height of 300 to 400 feet above the general level at Quoggy 

Joe and continues as Green Mountain into the unexplored region 

farther south. The hill as viewed from the east or west presents 

steep slopes from base to top, but the northeast side is easily ascended 

by following the ridge, difficult climbing being found only near the 

top. Angular blocks of light-colored rock varying in size from an inch 

to many feet in diameter cover the upper slopes. Wherever the rook 

is exposed on top of the hill it is cut by wide cleavage cracks which 

run continuously in the same direction (about northeast) for many 

feet. Less distinct cracks intersect these, so that the whole hill is 

seamed and fissured into giant blocks. So prominent and regular are 

these cleavages that the hill gives the impression of being a sedimentary mass. Quoggy Joe has a lake at its eastern base, and elsewhere 

is surrounded by swamps and forests, so that the limits of the igneous 

f mass could not be traced. The trachyte extends less than a mile from 

the hill to the east, as shown by the occurrence of sedimentaries just 

beyond Quoggy Joe Lake.

QUARTZ-TRACHYTE OF TOWNSHIP 9, RANGE 3.

The second occurrence of quartz-trachyte is on the Presque Isle 

River and is a very inconspicuous exposure, seen only as a small ledge 

extending from the bank. The rock as it appears in the ledge is 

specked with shining quartz and is exceedingly tough. The heavy 

vegetation prevents a determination of the width and extent of the 

mass, and even prevents definite ascertainment whether it is a dike. 

The locality is' difficult of access, owing to its distance from settlement 

and the lack of roads which can be used in the summer season.

ANDESITES.

Andesites are very rare rocks in eastern United States, but are the 

most abundant extrusives so far found in northern Maine. They form 

prominent hills and determine the general topography in some places, 

while in others they are represented by isolated remnants among the 

sedimentaries. The greater number of occurrences are of lava and 

breccia, but andesitic ash and tuff are also found well developed. In 

the following descriptions only the more important localities will be
112 CONTRIBUTIONS TO THE GEOLOGY OF MAINE. [BULL.16&

dealt with in detail; the less prominent outcrops will be spoken of in 

a general way. The andesites are located in the townships of Chapman, Mapleton, and Castle Hill, where, they constitute the prominent 

ridges known as Edmunds Hill, Hobart Hill, and Castle Hill, besides 

less noticeable masses.

EDMUNDS HILL ANDESITES.

Edmunds Hill is situated in Chapman Township near the middle of 

the north township line, and is simply the highest part of a ridge 

running north-south for several miles. The hill itself rises some 200 

feet above the road at its base, and presents the outline of a drumlin, 

so evenly has it been graded at each end. The trees, brush, talus, and 

glacial deposits entirely conceal the formations about the base of the 

hill, and it is only after climbing half the distance to the top that the 

bare rock is found in place. In climbing the west side of the hill, 

fragments of fossiliferous sandstone were found among the andesite 

blocks, and the sandstone ledge outcrops about 100 feet below the top. 

The thickness and extent of the sandstone could not be accurately 

determined, because it was covered in so many places with heavy 

blocks and small fragments of the igneous rock which had fallen from 

above. The contact was not seen. The entire top of the hill is of 

augite-andesite. The main mass is uniform in texture, and is cut into 

large blocks by cleavage cracks. When the blocks fall down the slope 

they remain as huge masses. The south and north ends, however, and ( 

part of the west side, are quite different. Here the rock is split up 

into long, thin slabs by a set of parallel cracks remarkably uniform in 

direction and length, which retain their parallelism even when the 

rock is folded or faulted. Cross cleavages intersect these cracks every 

few feet, so that when the rock is loosened it comes out in flat slaty 

pieces one-fourth inch or so in width and several inches, or even several feet, in area. The whole appearance is that of thin-bedded sedimentaries which have been folded and faulted (see PI. Ill, A). The 

general direction of these cleavage planes is N. 30° E. on the north end 

and N. 35° E. on the south end, with a dip southeast at a high angle. 

The fault planes strike N. 70° E., and, besides cutting out the thin 

slabs at the ends of the.hills, they occur all along the west side, each 

indicating a slight movement. It seems probable that the Edmunds 

Hill Ridge owes its origin, at least in part, to the formation of a fault 

block.

The outlying knobs and hills to the east of the main mass are also' 

of andesite, usually microcrystalline, but sometimes porphyritic. The 

igneous rock does not extend far to the west, but is replaced by arenaceous slates, and while no precise boundaries of the formation were 

determined, the field relations suggest that the hill is the remnant of 

a lava flow over the eroded and upturned edges of sandy rocks of 

Qrclovician age, .
U.S.GEOLOGICAL SURVEY BULLETIN NO. 165 PL.VII

(A) ANDESITIC LAVA-

(B) ANDESITIC BRECCIA.
GRKOOWY.] ANDESITES. 113

HOBART .HILL ANDE SITES.

This hill is an isolated mass of andesite forming a prominent feature 

in the landscape to the west of Presque Isle Village. It is situated 

partly in Mapleton Township and partly in Chapman Township, and 

is surrounded entirely by low, poorly drained swamps and forest lands. 

It is visited only for lumber and tan bark, which are secured in limited 

quantities during the winter season. The hill is about 1£ miles long 

and three-fourths mile wide, and rises quite abruptly above the plain 

to a height of 300 feet as a single well-defined mass without branches 

or outliers (see PI. Ill, J3). The sides are everywhere steep, and 

in places present cliffs 40. to 50 feet high. The top is bare only 

where fire has recently destroyed the vegetation. The talus slopes 

present a confused mass of large and small blocks of andesite, which 

entirely conceal all outcrops except where cliffs are exposed. On the

west and north sides numerous bowlders of red sandstone and conglomerate are piled along the slope and mingled with the volcanic 

material. These were traced to their parent ledges scarcely a half 

mile to the north, and the bowlders serve to cover the contact of the

Andes! tea. Slates. 

FIG. 4. Section on Mapleton-Presqne Isle road.

andesite with the Mapleton sandstone. Specimens collected from 

various places on the hill show but slight differences in composition 

and texture, except the rock from the northwest corner, which is a 

breccia of andesitic fragments and seems to be situated along a fault 

line. Here, as at Edmunds Hill, no actual contact between formations 

was observed, but -the sedimentaries were traced to the very base of 

the hill, and the facts indicate that the hill is a remnant of a lava flow.

SOUTH MAPLETON ANDESITES.

In addition to the prominent hills of andesite just mentioned, there 

are some ten or twelve less conspicuous outcrops in the fields in the 

southern part of Mapleton Township to the north and the south of 

the Mapleton-Presque Isle road. They usually occur as narrow ridges, 

and seem to be remnants of lava flows which once occupied former valleys, and are now left standing because of the erosion of the sedimentaries on both sides. The accompanying cut (fig. 4) illustrates tHe theoretical position ^f the andesite outcrops along the Mapleton-Presque 

Isle road.

Bull. 165- S
114 CONTEIBUTIOJSTS TO THE GEOLOGY OF MAINE. [BULL. 165. 

CASTLE HILL ANDESITES.

Castle Hill is the local name for the northern end of the high, narrow ridge extending north-south across the township of that name. 

While not so conspicuous a feature as Haystack Mountain, at the 

southern end of the same ridge, it forms the most considerable prominence on the immediate bank of the A-roostook River, and as all the 

early travel lay along this stream, the ridge was an important landmark to the first settlers. There is no common local usage as to the 

limits of Castle Hill, and in this report the term will be applied to the 

masses of andesite and volcanic elastics which lie between Aroostook 

River and the State road from Ashland to Presque Isle. It covers an 

area 2i miles long and varies in width from one-half to three-fourths 

of a mile. It is partly in Castle Hill Township and partly in Wade 

Plantation. The wagon road crosses the hill at the southern end, 

where it rises little higher than the surrounding plain. The east side 

has a gentle slope, and, being cut up into separate low knobs by small 

streams, the ridge effect is not apparent. The west side is formed by 

Welts Brook and t).e Aroostook River, which at this point is forced 

by it to take the abrupt backward turn so noticeable on the map. 

Calcareous and arenaceous slates are exposed in the bed of the river, 

while a short distance back steep slopes and cliffs of lava and ash 

rise to a height of several hundred feet. The hill is densely wooded 

and in places swampy, except at the southern end and along the east 

side.- At these points the bare rocks are occasionally exposed and 

present great variation in character. In one place heavy ledges of 

gray andesite are exposed, particularly on the knobs occupying the. 

northwest and southeast corners of lot 31. In the woods east of the 

mouth of Welts Brook is an outcrop of black silicified tuff between 

slates. On the southeast corner of the hill are loose ash beds containing fossils, coarse and fine volcanic breccias, and pumiceous lava in 

quite fresh condition. Where the old lavas have been planed off by 

glaciers and have been protected from weathering the outlines of 

bombs and pillows are plainly revealed. When weathered these bombs 

are loosened and drop out as oval or egg-shaped bodies with amygdaloidal surface and denser interior, and lie about thickly strewing the 

fields. In one place there is a cisternlike depression in the solid andesite some 10 ,feet deep and 30 feet in diameter, while close about it are 

piled a great number of very vesicular bombs and much glassy and 

brecciated ash. Its appearance suggests a small blowhole made by a 

single explosion. The striking fact about all the volcanic accumulations in the Castle Hill region is their freshness and their umistakable

character.

DIABASE.

Typical diabases have not been found at all in northern Maine, and 

rocks of diabasic habit and near enough in chemical composition to be
GREGORY.] - DIABASE. 115

classed as such are represented only by few outcrops, each of small 

extent. The most important exposure in the region is at Aroostook 

Falls, just over the international boundary line, in New Brunswick. 

Two small dikes of rock like that at Aroostook Falls were found crossing 

the east-west road about three-quarters of a mile northeast of Fairmount Station on the Bangor and Aroostook Railroad. The width of 

the dikes and their contact with the calcareous slates were not made out. 

Other diabase dikes of small extent are found at the southwest base 

of Mars Hill. Besides the above outcrops, which will be further 

described, rocks of diabasic character were noticed along the railroad 

2 miles west of New Limerick, and a good example of a sheared 

diabasic rock was observed in a cut at milepost 140, a little south of 

Weeksboro Station on the Ashland branch of the Bangor and Aroostook Railroad.

AKOOSTOOK FALLS DIABASE.

As noticed by previous writers, 1 this diabase occurs in a number of 

dikes cutting the blue limestone of the region, which at this place is 

closely folded and faulted along planes extending in more than one 

direction. The dikes are most abundant at the very foot of the falls, 

or series of rapids, where they have a uniform appearance and vary 

in size from mere dikelets 2 inches or more in width to a massive 

faulted and jointed dike 30 feet or more in width, which has affected 

the adjoining rocks in structure and texture. Most of the dikes 

trend N. 25° W., and dip W. < 60 ±, which makes them run at about 

right angles to the general strike of the sedimentaries. The dikes in 

the rapids above the falls form a series of abutments, causing narrows 

where they cross the stream, but they are so easily eroded that in 

other places they project little, if any, above the limestone which they 

cut, and if the present channel had not been occupied by the stream 

in recent geologic times, the dikes would be an inconspicuous feature 

of the river. As it is, the dikes can not be traced beyond the present 

valley.

MAES HILL DIABASE.

This diabase occurs in two dikes of different types situated close 

together on the southwest flank of the mountain. Walking up the hill 

from the McPherson house in the direction of the bare ledge on the 

southern summit, one passes over calcareous slates and sandstones and 

comes to a dense blue-black rock, which appears to be a diabasic dike 

in direct contact with the slate conglomerate. As one climbs higher 

and over thick beds of arkose, another outcrop of igneous rock is seen 

at the base of a long talus slope. This is a second diabase dike, or 

perhaps a flow, of unknown width and extent, which attracts the atten1 Jackson, Second Ann. Kept. Geol. Public Lands, 1838, p. 45. Hitchcc-ck, Agriculture and Geology 

of Maine, 1861, p. 215. Bailey, Ann. Kept. Geol. Nat. Hist. Survey Canada, 1885, Pt. G., p. 22.
116 OONTBIBUTTONS TO THE GEOLOGY OF MAINE. [BULL. 165.

tion of any observer because of the chunks of bright-red jasper 

included in it. It is at present impossible to locate these dikes accurately or to trace their boundaries, for the entire mountain side is 

overgrown with dense underbrush, which has grown up after burning and cutting off the large trees, and which makes the discovery of 

outcrops a matter of chance. The other outcrops of diabase are easily 

found, and present no peculiarities in their method of occurrence.

TESCHENITES.

The massive dikes of this rock form the most conspicuous geologic 

feature of the southwest part of Mapleton Township (see fig. 5). 

Few continuous outcrops are seen, but the many small exposures

FIG. 5. Map of part of Mapleton Township, showing teschenite area.

indicate a series of dikes in close proximity, extending about li miles, 

with a combined width of dikes and intervening slates of three-fourths 

of a mile. The places most favorable for study are on "lots 100 and 

107, but lots 106 and 108 furnish good outcrops, and the southeast 

half of lot 99 is practically composed of a hill of this material. One 

mile east of Mapleton post-office a road leaves the section line and 

turns south, in order to avoid passing over a hill, and the blasting and 

digging required in cutting this road have given an excellent geologic 

section for a distance of about a quarter of a mile across the strike of 

the sedimentaries and the direction of the teschenite dikes. The 

exposures sh'ow the country rock in this vicinity to be an arenaceous 

shale baked, at the contact with the dike, into a gray siliceous slate. 

The dike itself outcrops along the road for 400 feet, with great variation in appearance. " All these rocks have been well preserved by the
GREGORY.] TESCHENITES. 117

dense forest growth, and, when the moss and vegetable debris is 

removed, show their glacial grooving in a very fresh state. This large 

dike can not be traced to the east, but forms the hill immediately west 

of the road, and was found outcropping on lot 106, nearly a mile to 

the west. Forest and swamp prevented further exploration.

The large hill on lot 107 is another teschenite mass, which extends a 

half mile to the east and is terminated by two small knobs on lot 100. 

The ledges best exposed are-on the northeast corner of the hill, where 

they present a ragged ridge about 200 feet wide, which probably indicates the dike. This dike is separated from the one first mentioned by 

the sandy slates of the region.

On lot 106 the field relations of the teschenite are seen to the best 

advantage, for here the land has been cleared and plowed and a section 

running for a long distance directly across the strike can be examined. 

Here the large dike traced from the east is seen to take on a rude 

columnar form at the contact, with columns perpendicular to the wall, 

and it is seen to be sheared in a direction'rudely parallel with the slate 

bedding. Teschenite dikes and the slates alternate along the whole 

section. The dikes have black, dense border facies and coarse crystalline interiors, and contain many broken and hardened fragments of 

slates. The slates have a general strike N. 50° E. and dip SE. <60°, 

and are much folded and broken near the teschenites. In general the 

dikes follow the direction of the strike, but those taking' other directions are also present.

Besides this Mapleton area the teschenite outcrops on the State road 

at the southwest base of Castle Hill, but. the extent and character of 

its occurrence at that point have not been studied.
CHAPTER II I. 

CLASTIC ROCKS.

INTRODUCTION AND CLASSIFICATION.

In this chapter it is proposed to consider all rocks other than igneous 

which occur in the region covered by this report. Volcanic tuff, sandstones, limestones, and schists will be included in the description. All 

the material will be studied as varieties of rock, and from a lithologic 

point of view, without special regard to age or stratigraphic position. 

The pyroclastic rocks are treated of here rather than with the igneous 

rocks proper, because they are for the most part waterlaid, and are 

closely related to the sandstones and conglomerates of true sedimentary types.

In the scheme of classification which follows, the rocks have been 

divided into groups according to their composition as revealed in the 

hand specimen and by microscopic examination, precisely as if one were 

dealing with igneous rocks. The lines of demarcation have necessarily been somewhat arbitrarily drawn, for it was found that the tuffsandstone-limestone series is complete and that all members of the 

group are united by transition forms. The table on page 19 will show 

the general divisions, while further details will be given in connection 

with each group as it is taken up for discussion.

The phyllites, schists, and manganif erous iron slates have been studied only in general, but are believed to belong to'the same lithologic 

series and are accordingly assigned a place here. 

118
GREGORY.] CLASTIC HOCKS.

Classification of the clastic rocks.

119

Rock. Principal components. Typical exposures.

Volcanic tuffs.........

Volcanic sandstones 

and conglomerates.

Sandstone and conglomerates.

Calciferous sandstones 

Arenaceous limestone.

Slated limestone 

White limestone

Ash and lapilli (glassy).. 

Fragments of igneous 

rock.

1. Few fragments of igiieeous rock, quartz, 

feldspar.

2. Quartz, feldspar, and 

fragments of sedimentary rock.

3. Quartz and fragments 

of sedimentary rock.

4. Quartz, fragments oC 

sedimentary rock, 

and calcite.

5. Quartz and (little)

calcite. 

Calcite and quartz.. 

Calcite and (little)quartz.

Calcite 

Calcite

Slates and schists......

Manganiferous iron 

slates.

Castle Hill tuff. 

Conglomerate on Welts

Brook. 

Sheridan sandstone. 1

Chapman sandstone.

Mars Hill conglomerate.

On Sheridan road.

In railroad cuts south

of Masardis. 

New Sweden Township. 

Gritty beds in Aroostook limestone. 

Aroostook limestone. 

Fossiliferous limestone

at Ashland. 

Ashland. Branch. 

Wade Township.

l Tho general names applied to the sedimentary rocks in this paper were suggested by Professor 

Williams, and are further elaborated as to age and condition of formation in Part I of this bulletin.

VOLCANIC TUFFS.

Under this general heading will be included all the pyroclastic rocks 

of northeast Maine which contain lapilli and other original volcanic 

materials, and are thereby distinguished from volcanic conglomerates, 

which are composed principally of angular fragments of volcanic rocks.

FIELD DESCRIPTION.

The true volcanic tuffs are found on the southern half of the Castle 

Hill ridge, as outcrops in the road near the northeast corner of Ashland 

Township, and in several places on the Ashlaud-Sheridan road near 

the line separating these tAvo townships.
120 CONTRIBUTIONS TO THE GEOLOGY OF MAINE.

x CASTLE HILL TUFFS.

The most favorable place for the study of these rocks is in the open 

fields and along the roadside about one mile west of "Castle Hill Hotel, 

where they are found well exposed, in close connection with the andesites, on lots 31 and 32 (see map, fig. 6).

Normal type. While the southern Castle Hill tuffs differ considerably from one another in external and microscopic appearance, they 

are essentially alike and will be roughly classed together as the normal

type.

The outcrops of this type occur as low knobs or swells of land, always 

quite limited in extent and never forming marked topographic features.

Normal tuff. 

FIG. 6. Map of Castle Hill area.

SiHcifled tuff.

As might be expected in rocks of this class, the exposed surfaces show 

much alteration to a loose, porous rock, easily crumbled between the 

fingers and having the appearance of partly consolidated sand. 

Embedded in the tuff are many fragments of igneous rock, consisting 

mainly of rhyolite, vesicular andesite, and ashy or pumiceous fragments averaging about a quarter of an inch in longest diameter, but 

pieces are found as large as 6 by 10 inches. Corals and brachiopods are 

also found sparingly distributed in the coarser tuffs. On that part of 

the ridge known as Richardson Hill a conglomeratic facies is found in 

addition to the normal type.
VOLCANIC TUFF. x '12]

All these tuffs are waterlaid and show an assortment of the coarser 

and finer materials into a rude stratification, as the rock is seen in the 

ledge, and loose bowlders from apparently the same outcrops show 

their bedding distinctly. Cleavage planes running toward the northeast cut the ash beds, and small faults and slicken sided surfaces are 

commonly present. The embedded pebbles show results of strain, and 

occasionally are so cleaved and fractured that they drop into angular 

fragments when removed from their matrix.

Silicified type. An exposure of a hard, black silicified tuff was 

found on the brow of a steep hill about one-eighth of a mile east of 

the mouth of Welts Brook. The rock is broken into huge cubes by 

cleavages in the ledge, and loose blocks are strewn over the slope. 

The density of the forest growth and the thick mat of vegetable de'bris 

prevented a detailed study of the structural relations of this outcrop.

The relation of these volcanic ash beds to the other vocks of this 

vicinity was not made out with certainty, on account of the small number of outcrops and the absence of exposed contacts. So far as worked 

out, however, the facts indicate that the tuffs are contemporaneous 

with the andesitic fiows. The normal type of ash, the aa structure, 

and the andesitic lava and breccia all have their best development 

within a radius of a few hundred feet, and are believed to be near the 

original vent. The nearest sedimentaries are about an eighth of a mile 

distant on the east and somewhat nearer on the west, and wherever 

seen are clearly folded and occasionally baked. The present ash beds 

are considered as remnants of somewhat more extended beds which 

were laid down upon folded calcareous and arenaceous slates through 

which the volcanic vent had been drilled.

TUFF IN NORTHEAST PART OF ASHLAND TOWNSHIP.

The outcrop of volcanic tuff in this locality is on the north side of 

the lower Presque Isle-Ashland road, about 2£ miles west of Haystack 

Mountain, and is made up of ash in beds of differing aspect, together 

with an intrusion or flow of andesitic character. Part of the tuff 

appears in the field as porcelainlike material, while-the most typical 

ashy variety presents surface characters much like coarse amygdaloidal 

lava, for which it has been mistaken.

TUFF ON THE ASHLAND-SrrhmriJAN KOAD.

The volcanic tuff exposed in the road near the boundary line between 

Ashland and Sheridan townships is merely the most tuffaceous member 

of a number of outcrops which are all more or less pyroclastic in their 

composition and which are found along the road and in the river in 

this neighborhood. In speaking of this locality Hitchcock * notes the

1 Agriculture and Geology ot Maine, 1861, p. 391.
122 , CONTEIBUTIONS TO THE GEOLOGY OF MAINE. [BULL. 165.

presence of "very coarse conglomerates and trappean rocks," and of 

sandstones, "friable slates," "fine gray grits," and "conglomerates" 

farther to the west. All the varieties mentioned are composed wholly 

or in part of volcanic debris, and range in size of grain from microcrystalline to conglomerates with pebbles an inch or more in diameter. 

The coarser and finer tuffs are interbedded with the more typical sandstones and conglomerates, and give the appearance of dikes or beds of 

hard-baked feldspathic clays. The coarse tuff in particular resembles 

an igneous rock, and microscopic examination is required to determine 

its true character. It is doubtless on this account that the State survey overlooked the ash deposits of the region.

PETKOGKAPHY.

CASTLE HILL TUFFS.

The same division of the Castle Hill tuffs into normal type and 

silicified type will be made here as in the field description.

Normal type. This has its best development on the southeast base 

of Castle Hill, where it forms all the rock exposures seen, with the 

exception of the andesites on lot 31 (see map, fig. 6, p. 120). The 

ash on the west side of the wagon road contains the most numerous 

glassy fragments, as viewed by the unaided eye. It is light leadcolored on fresh surfaces and full of lapilli, which appear as white 

areas specked with black dots, made by calcite filling minute cavities. 

The rock breaks into rough fragments, but more easily along lines of 

partly developed cleavage or shearing. Weathering first forms a 

sandy coat very uneven in thickness, and finally the rock changes to a 

crumbling breccia. Specimens picked up from any part of the field 

show evident tuffaceous characters. The microscope shows the rock 

to be more than half composed of lapilli, which are present in two 

forms. These forms are as follows:

1. Lapilli composed of particles of white dust, which are isotropic, 

very angular in outline, with cusps, crescents, and sherds. In places 

the angles are rounded off and replaced by black dust, and again the 

characteristic outline of a former sherd shows, which is no longer 

glassy, but filled up with iron dust. They occasionally contain vesicles 

and show gradations in size up to 

2. Lapilli one-half millimeter in diameter, of white glass, perfectly 

isotropic, and filled with vesicles which may be large or small, separate 

or in coalescent groups. These vesicles are usually round, but occasionally are drawn out into ellipses and are now filled with secondary 

calcite or rarely with chlorite in radial growths. - Boundaries of the 

lapilli are made of concave recesses between projecting cusps formed 

by bursting of steam pores along the edge of the glass fragment. 

These larger lapilli show areas devitrified into feldspar laths with
OHEGORY.] NORMAL TUFF. 123

quartz, and again are broken up into dusty iron patches within the 

general lapilli boundary. The few feldspar crystals present are too 

badly altered to calcite to be definitely determined, and little aggregates of calcite grains and crystal sections are sprinkled through the 

whole groundmass. 

. PI. XIV, _Z?, shows the typical tuff for this region.

Some variations from this typical lapilli-filled tuff will be here briefly 

mentioned.

In the road running north-south along the east of Castle Hill the 

rock has much more the appearance of an argillaceous sandstone, and 

its ashy character is only revealed by weathering. The microscope 

shows quartz grains and fragments of andesitic material in addition to 

the vesicular glass and lapilli.

A specimen collected near the main outcrop of the normal type, as 

described above, was found by microscopic examination to be composed 

of large glassy fragments mixed with a few feldspar rods. The bubJbles in the vesicular igneous fragments are elongated and arranged 

rudely in rows. The whole structure suggests a lava stream which 

had been blown to fragments while in process of flow. The rock is 

now stained with iron and dotted with chlorite, while the interspaces 

and vesicles are filled with calcite.

The material forming the Richardson Hill knob, a,nd also that near 

the silicified tuff on lot 31, contains few lapilli, but much vesicular lava, 

quartz, and feldspar, and in some of its varieties passes into the volcanic conglomerates which are without fragments of glass.

On lot 31 there is a coarse variety of ash, loose-textured where 

exposed to the weather, and composed of angular and subangular grains 

of quartz and various volcanic fragments. The larger fragments are 

so firmly embedded that they break across when the rock is broken. 

A few fossils, mostly corals, are embedded with the rock fragments. 

The microscope shows all the grains to be angular, some remarkably 

jagged, and to consist of quartz in individuals or groups; feldspar, 

untwinned or with Carlsbad or albite twinning, and occasionally 

microperthite intergrowths; light-colored trachytic and andesitic 

fragments; microcrystalline masses of quartz and feldspar marked by 

perlitic cracks and representing devitrified glass, and finally lapilli with 

vesicles and characteristic outlines.

These looser-textured fossil-bearing ash beds on the southern slope 

of Castle Hill could scarcely be distinguished in the hand specimen 

from the sandstones of the Livingston formation in Montana, 1 and the 

presence of abundant andesitic fragments is common to the material 

from both localities.

TW. H. Weed, Bull. U. S. Geol. Survey No. 105. Weed and Pirsson, Bull. U. S. Geol. Survey No. 

139, pp. 49 et seq.
124 CONTEIBUTIONS TO THE GEOLOGY OF MAINE. [BULL. 165.

Analysis. The following analysis of tuff of the normal type from 

Castle Hill was made by Dr. W. F. Hillebrand, of the United States 

Geological Survey:

Analysis of tuff of the normal type from Castle Hill.

Constituent.

Si08 ...... ..............

AlgOj...... .............

FeA...... .............

FeO.... ................

MgO ...................

CaO.... ................

Na,0.... ...............

K,0.. ..................

H20-1050 -.. ............

H.,0+1050 .. ............

Ti02 ... .................

ZrO, ........--.-.---...

CV Cl

Per cent.

31.42

11.57

2.37

7.48

5.32

16.71

2.26

.74

.76

4.17

2.30

Trace.

Constituent.

\ V O

NiO.-.- ............ ....

MnO ....'..'.............

BaO.. ...................

SrO ....................

Li2 0. ...................

p r>

CO.....................

CL. .....................

Fe .....................

FeS ....................

Per cent.

.06

Trace.

.38

.64

None.

Trace.

.46

13.13

?

. ? '

.16

yy. yo

Discussion of analysis. In regard to the barium present in the tuff, 

Dr. Hillebrand says: "The barium exists as silicate, since the sulphur 

is all pyritic, and it does not appear as carbonate."

Sili'cified tuff of Castle Hill. The specimens of this tuff from the 

ledge east of the mouth of Welts Brook are black, exceedingly dense, 

hornstonelike rocks, with a fracture approaching the conchoidal, and 

have the appearance of metamorphosed siliceous breccias. The black 

groundmass is mottled with light greenish-gray areas, which are proved 

to be glasss by microscopic examination. Numerous cubes of pyrite 

with striated faces form a prominent macroscopic feature. Areas a 

square inch or more in extent, composed largely of small grains of 

jasperlike material, appear on the surface. Quartz-filled cracks intersect the specimen, and weathering does not proceed rapidly on exposed 

surfaces.

Microscopically the rock is practically a mass of glassy fragments 

thoroughly cemented together with silica. The larger and many of the 

smaller lapilli are greenish yellow in the section and are sometimes 2 

millimeters in diameter. They are divided into polygonal areas by dark 

lines, which appear to be incipient cracks filled with opaque material. 

The glassy fragments are broken and separated into distinct pieces, or 

split part way across, leaving wide cracks, now filled with siliceous 

cement. Areas are found composed of a mass of lapilli with cusps 

and concave spaces forming the outer border and having vesicular
GREGORY,] SILICIFIED TUFF. 125

structure within. These areas are in part devitrified and composed of 

quartz grains, but they always retain their vesicular structure. In 

other places devitrification has progressed until only dusty, opaque 

spheres remain in a quartz groundmass. Iron pyrite and grains of 

red jasper are quite generally distributed. With the exception of the 

structures described, the rock is siliceous. Sometimes the quartz is 

arranged as a tiny geode; sometimes there are areas of quartz bounded 

by a faint dark outline when viewed in plain light, and everywhere 

throughout the section groups of interlocking grains or individual 

grains, seen only with the highest magnifying powers, are present to 

the exclusion of other minerals and alteration products. The rock is 

considered a good example of a highly acid tuff now completely 

silicified.

TUFF IN NORTHEAST PART OF ASHLAN]) TOWNSHIP.

The tuff from this locality appears in the coarser variety as a dense 

blue rock, in which are found greenish-gray rounded and angular lapilli 

an eighth of an inch and less in diameter, whose aggregate amount 

comprises more than half the whole specimen. In weathering, the 

little spherical lapilli alter to a white porous substance, while the 

entire mass weathers dirty brown, giving the whole surface a peculiar 

spotted appearance, which has given rise to the idea that the structure is.amygdaloidal, and it has been described as such.

Microscopic description,. ^-Microscopic examination of sections cut 

from the finer-grained specimens collected at this place showed their 

unmistakable tuffaceous character, but they were too decomposed to 

be studied in detail. The coarser tuff, however, was seen to consist of 

rounded, pumiceous areas set in a groundmass composed almost 

entirely of minute lapilli, with their characteristic jagged and concave 

outlines. The spherical masses also are composed of minute glassy 

fragments! In addition to these glassy components, the rock contains 

a few feldspar crystals, some .fragments of mica, and areas of 

devitrified glass.

The rock is but slightly stratified, if at all. The fragments are all 

small and very angular, and minute glassy particles are abundant. 

These facts indicate an air-laid breccia.

TUFF ON THE ASHLAN-D-SUERIDAN ROAD.

The bed of volcanic tuff near the Ashland-Sheridan line appears 

as a dark-gray, mottled rock of light and dark areas, the nature of 

which is not evident in the hand specimen. Under the hammer it 

breaks into irregular fragments, and is traversed by a set of cleavage planes. Where it is much weathered the rock is not distinguishable on the surface from the volcanic sandstone with which it is 

associated.
126 CONTRIBUTIONS TO THE GEOLOGY OF MAINE. [BULL. 165.

Microscopic description. Under the microscope the slide presents 

some interesting features. The general mass is formed of areas composed of groups of feathery feldspars which branch and assume broomlike or bushlike forms. Often the brooms are arranged radially 

and have branches similarly arranged, and in such cases the ordinary 

spherulitic cross is seen between nicols. It seems evident that these 

areas are of devitrified glass, and it is possible, that some glass still 

remains. Other areas are made up of feldspar laths with trachytic 

structure and having their interstices filled with quartz grains.

The most unusual feature about the rock is the presence within the 

trachytic parts of aggregates of grossular garnets in well-developed 

crystals and irregular grains. With the garnets are associated quartz 

grains or calcite, rarely both, and in plain light the areas thus composed usually present a distinct polyhedral outline, as if some original 

mineral had been replaced. The origin of the garnets is not understood. 

It seems improbable that they should have been infiltrated into the rock 

in their present condition and occupy only particular places, and that of 

all the rocks of the region this tuff bed alone should contain them. They 

may, however, be due t'o metamorphism of some included fragment, 

as suggested by Osann 1 in the case of the andesites from Hoyazo, 

Cabo de Gata; but in the Maine tuff the original fragment is represented by a distinct polyhedral outline and hence could not have been 

an irregular schist pebble, but rather some crystallized mineral.

A piece of augite was found in the rock, and also a few badly altered 

feldspars. The alteration products are distributed in accordance with 

the materials composing the tuff chlorite in the glassy areas and calcite among the trachytic fragments. The latter mineral occurs also in 

patches throughout the rock and as the, filling of the cleavage cracks.

VOLCANIC SANDSTONES AND CONGLOMERATES.

As more fully explained at the beginning of this chapter, volcanic 

sandstones and conglomerates include all those clastic rocks composed 

principally of fragments of igneous materials. They are usually not 

much waterworn or rounded, and indicate rapid deposition of material 

frorfi a source not far distant. The separation of this class from the 

tuffs described in the last section is purely arbitrary and not indicated 

by field relations; and furthermore, even when examined in thin, section the two classes of rock are found to grade into each other. In 

amount of igneous material the volcanic sandstones and conglomerates 

range from those containing practically nothing else to those in which 

half or more of the rock is of quartz and sedimentary fragments.

1 Zeitschr. Deutech. geol. Gesell., Berlin, Vol. XL, 1888, p. 705.
GREGORY.] VOLCANIC SANDSTONES AND CON0LOMEBATES. 127

FIELD DESCRIPTION.

These rocks have been found on Welts Brook, west of .Haystack; 

on the Ashland-Sheridan road south of the volcanic tuff described in 

the preceding section; in Perham Township, outcropping in the road 

running east-west along the south side of the Little Madawaska ponds; 

in New Sweden Township, at the headwaters of and all along Bears- 

\Qy Brook; and on the east shore of Madawaska Lake.

VOLCANIC CONGLOMERATE ON WELTS BROOK.

This outcrop is in the line of the road running east-west on the north 

side of Haystack Mountain, and forms several low ledges a short distance east of the brook. In the field the rock appears as an indurated 

sandstone, varying in texture from very fine materials to conglomerates with fragments of slate 6 inches long. Fossils of several species 

were found here more abundantly in the coarser parts. A rude bedding is indicated by a succession of coarse and fine materials, but the 

variation is never abrupt and is rarely distinct enough to determine 

the position of the beds. The rock here is exposed for 100 feet or 

more along the bedding, and farther to the northeast similar material 

is found quite abundantly on lot 89, Castle Hill Township.

VOLCANIC CONGLOMERATES OF ASHLAND TOWNSHIP.

These occur in the road running northeast from Ashland and about 

2 miles from that village. In .the field this particular outcrop is not 

distinguishable from the other sandstones and conglomerates of Ashland and Sheridan townships. In fact, the field evidence shows that 

all the conglomerates of this region, ranging in texture from fine gilts 

to exceedingly coarse pudding stones, are parts of one series of beds, 

laid down under different conditions. Igneous material is in them all, 

and the present example, like the volcanic tuff next to it, is separated 

from the Sheridan sandstones on the arbitrary line of relative amount 

of volcanic debris contained. The beds are fossiliferous, and strike N. 

25° E.,-with dip < 40° NW.

VOLCANIC CONGLOMERATES OP NEW SWEDEN TOWNSHIP.

This rock is quite widely exposed about the headwaters of Bearsle}^ 

Branch of Madawaska River, and also oh the north bank of the stream 

about the middle of the township, and, in fact, forms practically all the 

northwest half of the township. The best exposure is a hill on the 

west line of New Sweden, on the south side of the little brooks which 

form the headwaters of Bearsley Branch. A continuous section is 

exposed here for about half a mile, and shows coarse conglomerates, 

sandstones, and arenaceous shales in beds 1 to 35 feet thick, forming a 

series which in position and material is practically the same as the one
128 CONTKIBUTIONS TO THE GEOLOGY OF MAINE. [BULL. 165. 

»

found on the Aroostook River in Sheridan Township. The strike of 

the beds is N. 60° E., with dips which indicate an anticline. With the 

exception of on® dense indurated specimen, all these rocks show, in the 

field, their rapid deposition and their origin from igneous fragments, 

and here, as in Perham and Sheridan, the most characteristic field mark 

is the presence of little fragments of slates which might be mistaken 

for plant remains.

VOLCANIC CONGLOMERATES OF PERHAM TOWNSHIP.

Outcrops occur in the vallej^ of Salmon Brook, where it' is crossed 

by the wagon road running east-west through Perham Township, about 

one mile south of the north township line. The section here presented 

begins at the schoolhouse on the east bank of the stream, with thin 

slates whose cleavage planes run N. 40° E., which are succeeded by 

fine, gray sandstones with slate and other fragments, striking N. 20°-E., 

dip E. < 75°. The sandstone on the west bank of the stream is very 

light gray, fine to medium grained, and is not distinguishable in the 

field from the volcanic sandstones in New Sweden and Sheridan, and, 

like them, contains few fossils.

There is every indication that the three sections of volcanic conglomerate described are sections across the strike of a narrow belt of 

sandstones and conglomerates extending from near Ashland Village to 

the north line of Perham Township.

VOLCANIC CONGLOMERATES OP MADAWASKA LAKE.

These are found typically .exposed on the east shore of Madawaska 

Lake near the wagon road. Along the shore and in the lake bed the 

rock is seen broken into massive blocks by intersecting cleavages. On 

the west the sandstone is bounded by reddish slates. The general rock 

structure and field relations closely resemble the Perham conglomerates, 

and are classed as part of the same general belt.

PETROGRAPHY.

VOLCANIC CONGLOMERATE ON WELTS BROOK.

The finer varieties of volcanic conglomerates found at this point 

appear in the hand specimen as medium-grained sandstones, gray in 

color and much hardened. Most of the grains are not determinable 

by the unaided eye, but a few quartzes and feldspars attain the size of 

buckshot, and in the coarser varieties fragments of quartzose rock and 

of black, green, and reddish, extremely dense slates, one-half inch to 1 

inch in their longest diameters, with subvitreous luster, are abundantly 

found. They are so firmly embedded that they break with the rock. 

Weathering proceeds very slowly and very unevenly, so that parts of 

the rock are decayed to great depth, while other parts equally exposed
GREGORY.] PETEOGEAPHY OF TUFFS. 129

are too well silicified to admit water, and hence remain quite fresh at 

the surface.

The microscope shows the rock to contain quartz and feldspar grains, 

with fragments of various igneous rocks. The quartz occurs both as 

partially rounded grains and as secondary filling of cracks. Feldspars, with orthoclase more common than plagioclase, are found in 

well-formed crystals, untwinned or with Carlsbad or albite twins, and 

microperthite intergrowths. The fragments of volcanic rock include 

andesite and trachyte, with a groundmass of ragged feldspars, often 

arranged in flow structure; fragments, perhaps of formerly glassy material now devitrified, showing feldspar needles in a dark cryptocrystalline 

groundmass, and fragments of vesicular lava with some glass formed 

by steam blowing back in the vesicles. Besides these evident volcanic 

materials, which constitute the bulk of the rock, there are also green, 

glassy-looking fragments microcrystalline which may be metamorphosed slates. Most of the components are with angular outline, 

and have associated with them chlorite and calcite with beautiful twin 

lamellae.

VOLCANIC CONGLOMERATES OP ASHLAND TOWNSHIP.

The volcanic sandstones and conglomerate from this locality range 

from dense sandstones to coarse varieties, but tj^pically have very 

angular grains 2 to 3 millimeters in diameter. The rock contains so 

much calcite as to resemble a finely brecciated limestone in places, 

and to cause it to effervesce freely with acid. It is blue gray in color, 

weathers to a white gray, and bears close resemblance to the rock 

exposed in Ashland Village, interbedded with the fossiliferous 

limestone.

Under the microscope the following components are seen: Quartz 

in large, broken, angular to rounded, interlocking grains, and small 

grains filled with inclusions, and feldspar represented by a few crystals 

now altered to calcite and volcanic fragments. The fragments of 

igneous rock comprise most of the material and are largely of andesite, 

and many large and small fragments of vesicular feldspathic lava with 

flow structure well developed. There are also areas with a pepper and 

salt appearance, which is taken to represent former glassy material or 

siliceous silt. Some mica is present, and calcite is abundant as a secondary product, and probably also primary as cement.

VOLCANIC CONGLOMERATES OP NEW SWEDEN TOWNSHIP.

This rock presents considerable variation in the field, and specimens 

from twelve different localities were collected for comparison. The 

coarsest variety is a dark, unassorted mass of angular and subangular 

fragments of quartz, andesitic and rhyolitic materials, granite, black 

and greenish glassy siliceous slates, and soft black slates, all set in a 

Bull. 165 9
130 CONTRIBUTIONS TO THE GEOLOGY OP MAINE. [BulL.165.

cement of similar materials. The fragments are at times 3 inches in 

the longest diameter, and the larger siliceous fragments show agate and 

geode structures.

The medium-grained varieties pass into sandstones and are light gray 

in color and marked by many small, black slate fragments of somewhat larger size than the general mass, but otherwise the rock is of 

very uniform texture. There occurs a variation from this mediumgrained type, in which the angular grains are quite widely separated 

by an unusual amount of finer-grained cement and in which occasional 

disks of slates an inch or more in diameter are found. On weathered 

surfaces these three varieties show the siliceous fragments projecting 

above the more readily dissolved cement, and their extreme angularity 

is thereby well displayed. Fossils are sparingly found in all these 

rocks.

A fine-grained variety is dark bluish gray on fresh fractures, and 

weathers white gray along zonal lines, which are quite .distinctly 

marked. No grains in this are large enough to be distinguished with 

the unaided eye, except the ever-present black slate fragments. One 

variety is so dense, indurated, and fine textured that it resembles 

igneous rocks of felsitic character and its nature is only revealed by 

the microscope.

Microscopic description. Several slides were prepared from the 

different varieties which showed close similarity in all points except 

size of grain. The medium-grained variety was taken as typical and 

was found to contain quartz and feldspar, with some accessory materials, 

in addition to the fragments of volcanic rock, which are the most abundant of all the components. The quartz is in broken, cracked, angular 

and subangular grains none round about one millimeter in longest 

diameter. Feldspar includes both orthoclase and oligoclase, the latter 

with bright lamellae. The' lava fragments are rhyolite, trachyte, and 

andesite, with the first two more abundant and with flow structure. 

Sedimentary material is represented by a few fragments of arkose and 

slate. Zircon grains are sparingly present. The cement is of fine material, identical in composition with the larger fragments, but altered to a 

yellow micaceous substance. Another variety is so largely composed 

of andesitic fragments as to deserve the name of andesitic tuff. The 

dense, indurated variety mentioned above is found to be made up of 

quartz grains and fragments of siliceous lavas. In all the varieties of 

volcanic conglomerates from New Sweden, so far as examined, microscopic fragments of brachiopods and other fossils were found.

VOLCANIC CONGLOMERATES OP PERHAM TOWNSHIP.

The volcanic conglomerates of Perham Township present a dark 

bluish-gray variety, in which the components are not megascopically 

discernible, and a light-gray variety of medium grain, occasionally con-
GREGORY.] VOLCANIC OONGLOMEEATES. 131

taining a large disk of some shaly material. They are fossiliferous, and 

at times the fossils occur as the center of balls an inch or more in 

diameter which are composed of material similar to the general rock 

mass, but which maintain their individuality and in weathered specimens drop out of the rock as spheres, or are easily removed with the 

hammer.

Microscopically this rock shows TIO peculiarities which distinguish 

it from the types described above, but consists of quartz grains, feldspar crystals, fragments of igneous rock of rhyolitic, trachytic, and 

andesitic facies, with practically no. fragments of sedimentary rocks. 

The cement is of the same material as the grains, and is usually dusty 

and of dark color.

VOLCANIC CONGLOMERATES OF MADAWASKA LAKE.

The volcanic conglomerates of Madawaska Lake appear in the hand 

specimen as a dark-gray rock of rather fine grain, which on weathering forms an ashy-gray outer zone. Round or oval,balls as large as eggs 

form a prominent field character, and are found abundantly embedded 

in the sandstones. They maintain their individuality through all states 

of weathering, and can be seen firmly set in the fresh rock, or partly 

loosened and resting in sockets, or as detached spheres along the lake 

shore (see PI. IX, B). These balls are of different material from 

the sandstone, and when broken open are found to contain no fossils 

and to show no concretionary structure.

The microscope shows the sandstone to be composed of angular and 

rounded grains of quartz, abundant feldspars, often striated, and many 

fragments of rhj^olitic and andesitic lavas. The slide prepared from 

an embedded sphere showed but few quartz and feldspar fragments, 

but instead was seen to be practically composed of fragments of a basic 

lava and augite crystals. The cement is of fine material of similar 

nature with considerable calcite added. It seems evident from this 

dissimilarity of composition that the embedded ball is a worn fragment 

of some fine-grained volcanic conglomerate already in existence at the 

time the Madawaska volcanic conglomerate was forming.

SANDSTONES AND CONGLOMERATES.

By referring to the table of classification given at the beginning of 

this chapter, it will be seen that sandstones and conglomerates include 

all the rocks of sandstone habit whose principal component is quartz. 

According to the amount and character of the other components, five 

divisions are made, as seen in the table referred to. These divisions 

are arbitrarily made for the most part, and it is possible to supply the 

transition forms. It is also true that no sharp line can be drawn 

between the volcanic conglomerates and the sandstones composed
132 CONTRIBUTIONS TO THE GEOLOGY OF MAINE. [BULL.IG&

partly of igneous material, and at the other end of the series there is 

likewise no evident line of separation between the calcite-bearing 

rocks and the gritty, partly calcareous layers in the limestone.

In size of grain these rocks range from very coarse conglomerate to 

microscopically fine-grained arkoses. All these variations will be 

grouped together and described according to their geographic occurrence as Sheridan sandstone, Chapman sandstone, Mars Hill conglomerate, Mapleton sandstone, and sandstones from other localities.

SHEKIDAN SANDSTONE.

This series is mentioned in Hitchcock's report1 by Packard, who 

also 2 describes a smaller section on Fish River Lakes. Bailey 3 has. 

also described the beds quite fully and has given a.list of the fossils 

contained in them. As stated above, these sandstones form one continuous series with the'volcanic conglomerates of Ashland and Sheridan, and are interbedded with them. Two parallel sections through 

these rocks were studied, the first on the State road, which follows the 

Aroostook River, the second in the bed of ^he river itself.

In the river section the rocks exposed for about 2 miles below the 

Ashland sawmill are argillaceous and arenaceous slates, red, gray, ancj. 

green in color, with an occasional embedded fragment of black slate. 

Interbedded with the slates are thin layers (one-eighth of an inch to 

10 inches) of greenish-gray calcareous material that weathers-more 

readily than the slates and resolves itself into a mass of broken crinoid 

stems. These slates strike N. 20°-40° E., and dip SE. <60°, while the 

slaty cleavage plane dips W. <50°. Succeeding these slates the river 

runs through sandstones and conglomerates for nearly 4 miles, while 

the outcrops along the wagon road repeat and supplement the section 

thus exposed.

Fine-grained variety. Of the river outcrops the one about one mile 

west of the east Sheridan line, and known locally as " Alley's grindstone," will be taken as typical for the finer-grained varieties. This 

outcrop is composed of three series of beds, as follows:

1. A very fine, even-grained sandstone,1 light gray or almost white in 

places, which attains a thickness of 20 feet and is broken into large 

blocks by cross fractures. Under the micrpscope a thin section of the 

rock shows quartz in angular and subangular grains, often in interlocking groups, and feldspars which are kaolinized orthoclase and 

fresh-looking plagioclase. The feldspar and quartz constitute about 

90 per cent of the. rock, but there are in addition many small fragments 

of slate, a few of igneous rocks of micropegmatitic character, and 

rarely biotite and zircon grains (see PL VIII).

1 Agriculture and Geology of Maine, 1861, p. 425.

S0p.cit.,p.423.

3 Ann. Rept. Geol. Nat. Hist. Survey Canada, 1887-88, Pt. M, p. 45. >
U.S.GEOLOGICAL SURVEY BULLETIN NO.165 PL.VIII

KiwilKii

&v._V';*>. -.?&'*&: Biftl&&\ *"-*"'i*hJ2i?

IT£;

^;

<A) FINE-GRAINED SHERIDAN SANDSTONE. 

(B) SHERIDAN SANDSTONE.

THL HELIOTVPE PRINTING CO.. BOSTON.
GREGORY.] SHEEIDAN SANDSTONE. 133

2. Beds a foot or more in thickness, somewhat coarser, but otherwise practically as above in general texture. They contain much larger 

and more numerous fragments of slate, and, as has been noticed by 

others, 1 several species of fossils which seem to decay readily and give 

the rock an arnygdaloidal aspect. These two varieties are ordinarily 

separated by 

3. Beds of very fine brown sandstone, one-half inch or more in thickness, which show mud cracks and appear as fine consolidated beach 

muds. The rocks of this section, particularly of the gray f ossilif erous 

beds, are duplicated near the store and church at Frenchville. The 

position of these fine beds on the river is, strike N. 100° E., dip S. < 10°. 

All the beds in this neighborhood have this strike, but the dip rises to 

50°-60°.

Coarse conglomerate variety. This is abundantly exposed along the 

State road, where it forms ridgelike hills, which are crossed by the 

road. Massive ledges of it outcrop on the river, and loose bowlders, 

sometimes 20 feet or more in diameter, lie in the stream and along the 

bank. All these conglomerates are practically identical in composition, 

but differ in amount of induration from loose sandstone to very compact specimens cemented with quartzitic material. Usually the alteration between coarse and fine strata occurs every few feet, but continuous layers of conglomerate with a thickness of 10 feet and more were 

observed.

The pebbles exposed by weathering are at times 6 to 8 inches in their 

longest diameter and are subangular to rounded in form. The pebbles found in these conglomerates are: quartz; granite; red, white, 

and greenish jaspers, agate, and other siliceous fragments; pieces of 

black slates; sandstones; quartzite; felsitic igneous rock; spherulitic 

andosite; porphyritic and amygdaloidal lavas. Of these components 

the siliceous subvitreous-looking fragments are most abundant and 

durable (see PI. IX, A). 

A thin section examined under the microscope showed the cement to 

be largely of rounded or subangular quartz and feldspar grains, often 

with striking intergrowth. The great variety of fragments of sedimentary and igneous rocks and of minerals present is unusual.

CHAPMAN SANDSTONE.

This sandstone covers a considerable area in Chapman Township 

and was examined at four outcrops: On the main road west of Quoggy 

Joe, on the south branch of the Presque Isle near Tweedy's, in the 

road near the southwest corner of the township, and at Edmunds Hill.

The most interesting occurrence is that on the Presque Isle River, 

and this will be described as representing them all. Here the rocks

1 Bailey, Ann. Kept. Geol. Nat. Hist. Survey Canada, 1887-S8, Pt. M, p. 45.
134 CONTKIBUTIONS TO THE GEOLOGY OF MAINE. [BULL. 166.

are exposed along the stream for about a quarter of a mile and show 

sandstones interbedded with slates, both having a uniform position 

with strike N. 80° E., dip W. < 50°. The sandstone is dark gray, 

fine grained, and uniform in texture, never approaching a conglomerate. Where fresh it presents a crystalline appearance much like 

quartzite. This is more particularly applicable to the Edmunds Hill 

sandstone.

Interbedded with these gray sandstones are thin beds of soft, yellowish, micaceous shales, which are often nodular and flaky, with irregular bedding. Embedded in this shaly layer on the side next the 

sandstone is a solid mat of fossils mostly brachiopods and lamellibranchs together with many plant impressions and occasionally carbonized remnants of vegetable forms. With.the fossils, or embedded 

alone in the edge of the sandstone, are pebbles of slate and of limestone 

at times 2 inches or more in length. These facts indicate that the 

Chapman sandstone was formed on a beach which was probably washed 

by tides or currents and overhung by cliffs composed of calcareous 

materials. . Under the microscope the rock is seen to contain quartz, feldspar, 

and fragments of sedimentary material. The quartz constitutes threefourths of the slide and occurs as rounded and angular grains, rarely 

interlocking and embayed, and often with dust inclusions. Feldspar 

crystals are few and usually are not well preserved. The rock fragments present are nearly all long, oval pieces of slate, and no 

undoubted igneous material was found. There are a few grains of 

garnet and zircon, and much stringy micaceous and chloritoid material, which, mixed with quartz and calcite, forms the cement.

MARS HILL CONGLOMEEATE.

Mars Hill is the most prominent landmark on the international 

boundary. All about the mountain and up to its very base the ordinary slated limestones of the region form a rolling plain about 500 feet 

above sea level. Above this the mountain rises to a total height of 

1,695 feet above tide, as measured by the aneroid, and covers an area 

about 2^- miles long and half a mile wide. It is densely forested except 

at two localities on the southwest corner and a partly cleared area at 

the north end. This makes a final determination of structure and 

composition impossible at present.

The mountain seems to have been first visited for geologic purposes 

in 1838, when Mr. Hodge, of Dr. Jackson's party, found here and there 

'' outcropping ledges which proved on examination to be grauwacke, 

exactly like that on Sugar Loaf Mountain, and like that rock belonging to the regular Anthracite Coal Measures."* Hitchcock 2 refers to

1 Jackson, Second Ann. Kept. Geol. Public Lands, 1838, p. 46.

2 Agriculture and Geology of Maine, 1861, p. 386.
U.S.GEOLOGICAL SURVEY BULLETIN NO. 165 PL.IX

(A) CONGLOMERATE OF THE SHERIDAN SANDSTONE SERIES. 

(-B) SANDSTONE FROM MADAWASKA LAKE.

THE MELIOTYPE PRINTING CO.. BOSTON.
GKEGOKY.] ^ MAES HILL. 135

these rocks as Devonian sandstone, and states that they are of the same 

age as the red sandstones of Mapleton.

Rock structure. With the exception of the igneous rock described 

in another chapter, Mars Hill is composed of a conglomerate which in 

places becomes quite fine grained. The structure of the mountain and 

the relation between the different rock formations are shown, by the 

section, fig. 7. . The section is made straight east from the Boynton schoolhouse to 

the top of the mountain.

Near the schoolhouse occur the sandy, calcareous slates of this region; 

nearer the hill is a layer of very fine sandstone, about 50 feet wide, 

which is composed of quartz grains with some feldspars set in a calcite 

cement. Extending from this sandstone to the base of the hill, » distance of about half a mile, is a whitish to blue brecciated limestone, 

which is closely folded and faulted and cut by cleavage planes that 

are now filled by secondary calcite. The limestone is not uniformly 

calcareous, but contains sandy streaks, especially near the hill.

FIG. 7. Section at Mars Hill.

The lower slope of the hill is of medium-grained breccia composed 

of fragments of sandy slates and sandstones, which soon passes into a 

very coarse, rough breccia composed of large fragments of sandy and 

argillaceous slates, together with fragments of arkose and other varieties of sandstone and rarely a fragment of an igneous pebble. The 

fragments are subangular. The whole mass is slated and sheared and 

has all bedding lines destroyed.

From halfway up the mountain to the top the slate fragments, which 

are so abundant below, disappear as the predominant element in the 

rock, and are replaced by pebbles of sandstone, arkose, quartzite, 

hardened slates, and white quartz. The pebbles are rounded and vary 

from those that are fine-grained to those4 inches and more in diameter. 

The cementing material is very firm, as is shown by the fact that the 

cleavages break through the pebbles.

The sandstones and conglomerates exposed on other parts of Mars 

Hill are much like those in this section, and show variation in fineness 

and amount of induration.
136 CONTEIBUTIONS TO THE GEOLOGY OF MAINE. [BULL. 165.

Microsections cut from the rock at the north and south ends of the 

mountain revealed the same composition, although varying in relative 

size and abundance of the compound fragments. The materials found 

are rounded, lengthened fragments of sandy schists or slates, which 

have been bent and stretched, and rounded fragments of sandstone 

composed largely of quartz and feldspar grains, which in places are 

broken into parts that have moved since fracture. The general cement 

is of quartz grains, with some feldspar and numerous sheared fragments of slate.

The Mars Hill conglomerate is quite distinct from all other sandstones and conglomerates so far found in northeast Maine. The 

absence of igneous fragments is noticeable, and the great abundance 

of slate fragments makes it almost a slate conglomerate. The sheared 

and broken condition of the whole mass and of its individual pebbles, 

and its intimate association with the crumpled, and brecciated slates and 

limestones at its base, indicate an age at least as great as the Aroostook 

slated limestone, and it is considered, on lithologic grounds alone, to 

belong to that series.

MAPLETON SANDSTONE.

Nearly all the eastern half of Mapleton Township is overlain by red 

sandstones and conglomerates, which form rounded hills, with many 

good exposures. Outcrops occur on the State road about 3 miles 

from Presque Isle and on the Mapleton road about 1£ miles from the 

village.

Winslows tlill section. This section affords the best opportunity for 

study. An east-west road that branches from the State road about 

\\ miles from Presque Isle Village runs over the top of the hill and 

crosses the strike of the different beds. The outcrops on the hill form 

a reasonably complete series, and will be described as representing the 

whole Mapleton sandstone area. Beginning at the east base of the 

hill and extending about halfway to Winslow's house is a series of 

reddish-brown sandstones and coarse conglomerates in beds 10 to 30 

feet thick. The heavier beds of conglomerates are near the bottom 

and become inconspicuous toward the top of the hill. The compact 

beds of fine red sandstone appear to be first-class building material, 

although the dip into the hill will make quarrying expensive.

Above these coarse and fine red rocks are other fine-grained sandstones, which are gray in color and have much the appearance of the 

Chapman sandstones. They form the top of the hill, and occur in 

thick beds, with an occasional stratum of coarse material a few inches 

in thickness. *

The thickness of the whole series as exhibited by this section is 215 

feet, of which 180 feet is of the red sandstones and conglomerates.
GREGORY.] MAPLETOF SANDSTONE. 137

The strata dip NW. < 15° ± and have an average strike N. 45° E. The 

section is shown in fig. 8.

Petrography. The conglomerate varies from fine consolidated gravel, 

partly water sorted and marked by cross bedding, to a confused mass 

of pebbles 2 to 3 inches in diameter. The pebbles contained are 

quartz, reddish and greenish jasperlike fragments, blue limestone, 

white limestone, calcareous slates, quartz-porphyries, and occasionally 

fragments of other igneous rocks. Thin sections examined under the 

microscope show that the fine sandstones are practically identical with 

the conglomerates in composition, and that the cement of all the varieties is largely calcareous, with a mixture of iron.

In the red sandstones near the hilltop are abundant remains of a 

branching Psilpphyton and other Devonian plants, but diligent search 

has failed to reveal other fossils (see PI. XII, A).

Field relations. At no place was an actual contact between the 

Mapleton sandstones and the common slated limestones of this region 

observed, but outcrops of the two formations were found near each 

other in several places, and wherever seen the limestones are much 

folded 'and slated and dip at high angles, while the sandstones .dip

FIG..8. Section through Winslows Hill.

slightly and show little disturbance since deposition. On such evidence 

it is believed that the Mapleton sandstones lie unconf orinably upon the 

slated Aroostook limestones.

These sandstones were examined by Hitchcock, 1 who called them 

.Devonian. The field.measurements which he made could not be verified. Bailey 2 considers them to be of Lower Carboniferous age, and in 

describing this region appears to extend the sandstone area, and mentions vesicular gray sandstone 4 miles from Presque Isle, presumably 

on the Haystack road. In this vicinity, however, no rocks were seen 

except many outcrops of decayed porphyritic andesite.

SANDSTONES OF OTHER LOCALITIES.

Outcrops of a fine-grained sandstone with a decided quartzite appearance and fracture are exposed on Johnsons Brook, New Sweden; on 

the North Branch of the Caribou in Woodland; on the Aroostook

1 Agriculture and Geology of Maine, 1861, p. 425.

2 Ann. Re*pt. Geol. Nat. Hist. Survey Canada, 1887-88, Pt. M, p. 47.
138 CONTRIBUTION'S TO THE GEOLOGY OF MAINE.

River in Wade Township; at Masardis, and in railroad cuts south of 

Masardis. The exposures are usually but a few feet wide and can 

seldom be traced for more than 100 feet. They form thin beds in the 

slates and 'limestones and remain as small ridges after the softer 

sediments have been worn away.

In thin section under the microscope they appear as an aggregate of 

quartz grains closely united, and with them considerable calcite is 

found, both in grains and as the cementing material. A few shreds of 

white mica, iron grains, and feldspars are usually also present.

These lime-bearing sandstones are geologically unimportant, and are 

mentioned-to show their lithologic relationship. As indicated by the 

table given at the beginning of this chapter (p. 119), they are considered as a transition between the true sandstones and those with about 

equal amounts of quartz and calcite.

CALCIFEEOUS QUARTZITIC SANDSTONE.

Under this head are included rocks of a peculiar type which have 

been called in the field felsite, quartzite, slate, and limestone. They 

occur as beds 15 feet or more in thickness, and as thin gritty layers in 

the limestone, and have a composition, as revealed by the microscope, 

of about half calcite and half other minerals, largely quartz.

These rocks are sparingly distributed in the eastern part of the section under discussion, and have not been found at all west of the Haystack Ridge. The outcrops easiest of access are at Washburn Ferry, 

on the north bank of the Aroostook River, and in the wagon road 

about 1 mile east of the Castle Hill Hotel. An outcrop in the northwestern part of New Sweden was found interbedded with fossiliferous 

slates by which its age has been determined.

Wherever the sandstone has been found it presents a light-gray, 

glistening surface, and looks in the hand specimens like a quartzite. 

It has an uneven fracture that is sometimes conchoidal, and it weathers 

by forming a distinctly bounded yellow-brown zone, immediately inside 

of which the rock presents a uniform fresh appearance. This method 

of weathering and the generally massive character of the beds are 

strikingly like many fine-grained feldspathic igneous rocks, and have 

given rise to confusion in field terms. Examination of microsections 

shows an exceedingly dense rock composed of calcite and other carbonates, quartz, feldspar, muscovite, and iron. The amount of quartz 

varies in different slides from about 50 per cent down to 15 per cent, 

but without greatly affecting the general quartzitic appearance of the 

rock. The muscovite is entirely absent in some slides and pyrite is 

occasionally present.

Analysis. Owing to the uncertain character of this rock, Dr. W. F. 

Hillebrand made the following analysis of the specimen from New
GKEGORY.] CALCIFEKOUS SANDSTONE. 139

Sweden Township, as this is the most highly calcareous and micaceous 

of all the specimens of this type collected:

Analysis of caldferous sandstone.

Constituent.

Si08 ...... ..............

AW...... ............

FeA .......1. .........

FeO... .................

MgO. ....... ...........

CaQ .................

Na2 0. ..................

K20.... ................

HA-1050 ... .----.--.--

H20+105°.. ............

Ti02 ...... ..............

Zr02 . ...................

CrA-------------------

Per cent.

54.23

7.38

.54

1.37

3.29

14.56

- 1.65

.1.74

.25 

1.22

.28

?

?

Constituent.

VA -------------------

NiO... ..................

MnO. ..................

BaO ....................

SrO. ....................

Li A -------------------

P O

00,...'. ................

01......................

Fl...... ................

FeSj,... .................

Per cent.

?

None.

None.

None.

.07

13. 48

?

?

?

100. 06

The mineral components were calculated from this analysis and gave 

the following approximate composition:

Mineral.

Alkali feldspar. .........

Magnesite ..............

Muscovite ..............

Per cent.

52.0

18.0

13.7

(5.9

4.0

Mineral. Per cent.

2.1

2.8

.5

100. 0

LIMESTONES.

Limestones are by far the most abundant and most widely distributed rocks of northeast Maine.. 'They never occur as undisturbed 

beds, but are everywhere folded and slated and in places are brecciated 

to an extreme degree. Thick beds are rare, and generally the lime-, 

stones are thin and uneven in bedding and interstratified with sandier 

materials, indicating the Vdeposition of calcareous muds under the 

changeable conditions foun'd near shore. Different specimens show 

considerable variation in the amount of material other than calcite 

present, and a series could be selected showing all gradations from 

the calciferous sandstone described above to the white fossiliferous 

limestone.
.

140 CONTRIBUTIONS TO THE GEOLOGY OF MAINE. [BULL. 165.

As shown by the table on page 119,. limestone will include those calcareous rocks with considerable quartz, those with very little quartz, 

and those of calcite alone, and they will be described as ai'enaceous 

limestone, slated limestone, and white fossiliferous limestone.

ARENACEOUS LIMESTONES. .

Rocks of this class occur as thin beds among the more calcareous 

members of the Aroostook limestone series, or as wide beds forming 

hills of considerable size. A good example is found in the railroad 

cut half a mile south of Presque Isle Station, and also in the road near 

the Academy Building, where the rock has the appearance of a quartzite sandstone interbedded with limy slates. It is cleaved and sheared, 

and has the recemented cracks common teethe slated limestones. To 

the naked eye the rock is uniform in texture and composition, but 

under the microscope a thin section shows stratification caused by variation in the amount of quartz present in the different lamina.

The largest exposures of this rock are on a hill about half a mile 

west of Spragueville and on the North Branch of the Presque Isle 

River, where it crosses the corner of Chapman Township. The rock is 

identical in both places, and only the Chapman section will be described. 

Rising from the river at Littlefields is a low, rounded hill or ridge, 

which is partly bare of vegetation and shows a number of good exposures. At the eastern base is a light-gray limestone, in places quite 

pure and uniform, but for the most part composed of -angular fragments of limestone closely cemented together and containing numerous 

brachiopods and other fossils. This is apparently the same limestone as 

that observed on Dudley's farm, 3 miles to the northwest. In one place, 

near the northeast base of the hill, a contact between the white limestone and the arenaceous limestone was observed, and from the condition of the rocks it seems evident that crushing has taken place along 

the contact plane. A confused mass of pebbles of the two rock types 

now represents the contact.

Joining the fossiliferous limestone on the west is the arenaceous 

limestone, which is here shaly, weathers yellow brown in distinct zonal 

banding, contains many large, rounded nodules and lentides of the 

same material, and is marked by Orthoceras fragments.

Farther up the hill the rock has a dark-gray color/is broken into 

 thin slabs, and glistens with micaceous specks. The' fossils here are 

graptolites. The rock nearest the hilltop is more sandy and contains 

crinoids, corals, and other organic remains.

Judging from the position of the fossils, the beds of this series 

.strike .N. 35° E. and dip W. < 60°. Intersecting cleavage planes have 

broken the strata into blocks.

Under the microscope slides prepared from rocks of this class 

showed that calcite in rounded or irregular grains and in strings and
U. S. GEOLOGICAL SURVEY lULLETIN NO. 165 PL. X

A RAILROAD CUT AT HOULTON : SHOWING SLATED AROOSTOOK LIMESTONE.

J! RAILROAD CUT AT TiMONY ROAD, SHOWING FOLDED AND FAULTED AROOSTOOK

LIMESTONE.
GKEGORY.] AEOOSTOOK LIMESTONES. 141

flakes constitutes about five-sixths of the material present, and that 

quartz grains, with a little muscovite and other accessories, compose 

the remainder.

Arenaceous sandstones of the same general character occur on the 

Aroostook River near the granite and along the railroad 2 miles east 

of Ashland Junction.

- AEOOSTOOK LIMESTONES.

This term is proposed for the thin-bedded, slated limestones which 

form, the most widely distributed sedimentary rock type of this whole 

section of the North American continent. Its extent in northeast 

Maine is shown on the geologic map, and its yet more extensive distribution in New Brunswick and Quebec is shown by an examination 

of the Canadian reports. The Aroostook River has cut its wide valley

through this formation from Wade Township to its mouth, and has 

revealed the rock structure at many points along its course. The St. 

John River also flows over rocks of this series, and at the Grand Falls 

presents a good section for study of its lithologic character. In general, the limestone area is a low plateau about 500 feet above sea level, 

with a rolling surface made by rounded ridges between slowly running 

streams. The valleys are in general broad, and the whole region indicates an advanced stage of topographic development.

Previous study. The wide distribution of limestones has given this 

region rich agricultural land, which attracted settlers at an early date 

and gave the geologists the advantage of roads and cleared fields. 

The general monotonous character of the outcrops, however, gave 

little opportunity for special study. The members of the Jackson 

survey gave little information in regard to the series. Hitchcock 

briefly decribes the" section from Houlton to Presque Isle, 1 and calls 

the rocks calcareous slates and limestones of Upper Silurian age. 2 

The most complete study of the slated limestones has been made by 

Professor Bailey, 3 who reviewed the work of previous writers and 

described the New Brunswick area in detail. He regards the following as the probable succession of strata, in descending order:

Gray or greenish-gray (bluish weathering) argillites, with occasional alternating 

beds of greenish-gray sandstone.

Gray, green, and bright-red slates, holding heavy beds of manganiferous hematite.

Gray, highly calcareous slates, conspicuously "banded on weathered surfaces, including at various points heavy beds of limestone, which are more or less fossiliferous.

Gray, calcareous, and buff-weathering sandstones and slates, holding remains of 

crinoids, corals, brachiopods, and graptolites.

Gray, calcareous conglomerates and sandstones, holding pebbles of Cambro-Silurian 

rocks.

1 Agriculture and Geology of Maine, 1861, p. 385.

3 Geology of Northern New England, p. 3.

3 Ann. Kept. Geol. Nat. Hist. Survey Canada, 1885, Pt. G, pp. 11-23.
142 CONTBIBUTIONS TO THE GEOLOGY OF MAINE. [BULL. 165.

The data at hand for the determination of the succession of the rocks 

in the limestone series are very meager. The extremely disturbed condition of the rocks and the scarcity of fossils make a final interpretation 

of their age and structure at present impossible. The many cuts 

along the line of the Bangor and Aroostook Railroad give a better 

opportunity to determine the composition and position of the different 

beds than has heretofore been afforded.

Structure. As seen in the field the limestone masses never present 

angles, but have their corners "rounded off, and contain small sink 

holes in limited areas. The beds are very thin, usually from a fraction of an inch to a few inches in thickness, and rarely several feet. 

They are distorted and folded to an extreme degree along axes which 

run approximately northeast. The folds are at times 15 to 20 feet 

broad, but commonly are merely minute twists and plications, several 

of which may occur within a few feet. The apices of the folds are 

often enormously infolded and distorted on an almost microscopic 

scale. In one place thirteen complete miniature anticlines were 

counted, the total length of which was 9 inches from apex to apex, 

but was over 3 feet measured along the beds. In addition to the folds, 

there are countless faults, but always, so far as observed, on a small 

scale. Slickensides are formed in nearly every outcrop, and in places 

take the form of a succession of approximately parallel grooves along 

which movement has taken place. . The grooves are n ow occupied by 

flattened columns of arenaceous limestone.

The average strike of the strata is about N. 60° E. in the southern part 

of the area, and N. 30° E. in the northern part. The dips are usually at 

 high angles. Since folding has taken place the beds have been slated 

by planes running about northeast, which often nearly coincide with the 

bedding and are always more prominent than the bedding planes. 

Unusual caution is therefore required in taking measurements of dip 

and strike. Other sets of cleavage planes are present, and often serve 

to cut the strata into rhombs.

Petrography. The exposed rock surfaces are coated with a thin, 

yellowish-white weathered zone. Owing to the varying amount of 

impurities in the beds the rock takes on a banded appearance, which 

is much intensified where metamorphism has been active. The rock 

itself is quite uniform throughout its whole extent and is of .a typically 

grayish-black color, becoming a lighter gray in the more sandy beds. 

It is extremely dense, and under the highest powers reveals masses of 

exceedingly fine-grained calcite arranged in layers which vary slightly 

in size of grain. Quartz and fragments of mica and iron are also 

occasionally present.

Hea/vybeds of limestone. Heavy beds of limestone, sometimes 10 

feet and more in thickness, are found with the typical thin-bedded 

variety, especially between Presque Isle and Fort Fairfield and in the
U.S.GEIOLOGICAL SURVEY BULLETIN NO. 165 PL.XI

BANDED LIMESTONE. 

AROOSTOOK LIMESTONE.

THE. HELIOTYPE PRINTING CO., BOSTON.
GKEGOKY.J FOSSILIFEEOUS LIMESTONE. 143

big limestone cuts on the Bangor. and Aroostook Railroad between 

Ludlow and Ashland Junction. These heavy beds are not so closely 

folded, but the apices and troughs are altered to marble in places and 

the strata are broken into massive blocks. Generally speaking, the 

limestones in the vicinity of Houlton are more evenly slated, more 

arenaceous, and not so closely folded as in the Aroostook Valley.

The disturbances through which these rocks have passed seem to have 

destroyed the fossils to a large extent, for although diligently searched 

for at many places, the number of species found is remarkably small.

(See Pis. X, XI for illustrations of Aroostook limestone.) 

i

FOSSILIFEROUS LIMESTONE. 1

Fossiliferous limestone is found in and near Ashland Village, at 

Dudley's in eastern Castle Hill, in the northwest corner of Chapman 

Township, and in the well-known Square Lake locality. In Ashland 

Village the rock is whitish brown, much broken and brecciated, and is 

practically composed of fossils in all stages, from complete forms to 

finely comminuted fragments. The. field appearance is of a rough 

groundmass, irregularly broken into blocks. Two hundred feet to the 

south this brecciated material is overlain by regular beds of dark 

fossiliferous limestone conglomerate, which is here interbedded with 

shales containing rolled pebbles, and nodules. The limestone beds are 

occasionally pinched out or occur as lenticles. South of the village 

the outcrop on the west of the road shows white limestone with 

abundant fossils, while east of the road, li miles south of Ashland, the 

rock is a conglomerate, in which limestone, sandstone, and shale are 

promiscuously mingled.

The Castle Hill and Chapman occurrences are substantially alike, and 

only the former will be described. The outcrop is best exposed on 

Mr. Dudley's farms, near the house and on both sides of the road. 

Here the white limestone is embedded between slates which strike N. 

40° E. and dip E. < 70°. The slates on one side are the ordinary calcareous slates of the region, but immediately adjoining the limestone 

on the west the slates are black and reddish, with heavy staining of 

hematite and manganese. The fossiliferous limestone here is dark 

gray, and fragniental material from various sources is mingled with 

the abundant fossils.

SLATES AND SCHISTS.

' The Ashland branch of the Bangor and Aroostook Railroad crosses 

the strike of a series of slates and schists, and where cuts have been 

made furnishes good exposures for study. No detailed work has been 

done on these rocks, but a few general statements mav be found useful.

iThis limestone is named and described as the Ashland limestone in Part I of this report.
144 CONTEIBUTIONS TO THE GEOLOGY OF MAINE. [BULL. 165.

Near the bridge at Smyrna Mills the slates in general are steel-blue 

in color, and so fissile that they split into flakes as thin as paper. The 

slating is very regular in a plane which strikes N. 70° W., with a dip 

N. < 80°. Another plane of cleavage runs N. 40° E. and cuts the 

slates into large blocks. Interbedded with slates are thicker black clay 

layers and thin beds of micaceous sandstone. In two cases the sandy 

beds are replaced by coarse indurated conglomerate containing large 

rounded fragments of quartz, black slate, and fine grits. Only rarely 

do these coarse layers extend for any distance, but are commonly 

pinched out between the other beds.

Along the track to the north of Smyrna Mills the slate's are found 

to be much crumpled and distorted, and vary in color from green .to 

gray, with occasional reddish layers. They all have a smooth surface, 

especially the green varieties, and the sandier layers are not prominent. In a cut south of milepost 117 are black slates with the steelblue variety, having their bedding planes marked by a thick sprinkling 

of brilliant crystals of iron pyrites. The beds at this place strike 

N. 80° E., dip south at a high angle, and the cleavage runs .east-west.

At Weeksboro, near the station, the slates are light gray, with very 

soft and greasy feel. They are folded, faulted, and twisted to an 

extreme degree, and show many small slickensides. The cracks are 

now filled with quartz, which indicates the amount and character of 

the distortion. All bedding and regular slating are here destroyed, 

and the rock breaks up into chips and irregular slabs.

Near St. Croix Station the slates approach more nearly the character of "typical phyllites. They are here steel-blue in color, somewhat 

micaceous, and split regularly into very thin slabs which strike eastwest and dip N. < 80°. Thin beds of fine sandstone occur with the 

slates.

Northward from St. Croix the sandy layers become a more prominent 

member of the phyllite series, and at the Mill Seat on the St. Croix 

River the rocks are micaceous sandstones in beds 2 inches to 2 feet 

thick, interbedded with blue-black slates, which are very smooth and 

have a greas^ feel. On weathering, all the rocks at this place assume 

a pure white appearance, like a smoothly finished plaster wall. The 

finer layers are largely composed of minute, mica flakes. The beds 

strike N. 85° E. and dip N. < 80°. One slaty cleavage is parallel with 

the bedding, while another prominent cleavage runs N. 20° E. and 

dips E. < 70°, thus cutting the beds into rhombs.

At the "foot of dead water" on the St. Croix, in T. 9, R. 5, the 

rocks exposed are gritty slates with indistinct bedding. In the railroad cut at this locality the rocks show a number of broad folds with 

minute plications on the limbs, and the beds are stretched and pinched 

out in places. Embedded in these slates are two big bowlders of igneous rock to which the slates have adjusted themselves. It is thought
U.S.GEOUDGICAL SURVEY BULLETIN NO. 165 PL.XM

(A) MAPLETON CONGLOMERATE.

MANGANIFEROUS IRON SLATE.

THE. HELIOTVPE PRINTING CO., BOSTON.
GREGORY.] . SLATES AND SCHISTS. 145

that these bowlders may have been carried out in the Paleozoic sea by 

the ice and deposited as we now find them. The various cleavages 

found in the slates have not affected the igneous blocks.

The other outcrops found in this township, and also in Masardis, are 

sandy slates and fine micaceous or feldspathic sandstones, with occasionally a limestone bed. West of Masardis the beds are sparingly 

fossiliferous.

MANGANIFEROUS IRON SLATES.

In his second report0 Dr. Jackson 1 described at considerable length 

beds of "compact red haematite" found on the Aroostook River in 

what is now the southeast corner of Wade Township.^ The analysis 

made at that time showed 76.80 per cent of peroxide of iron, and the 

calculated amount of iron in sight at this outcrop was 97,200 tons, and 

a connection between this bed and the one near Woodstock, New 

Brunswick, was assumed.

Besides the locality described by Dr. Jackson, outcrops of this 

manganese-bearing iron slate were found on Dudley's farms, in southeast Castle Hill, and on the State road half a mile west of the MapletonCastle Hill line. Similar slates, containing less iron, occur also in 

Woodland and New Sweden. In all these cases the ore occurs as stains 

on slate, which is interbedded with the ordinary slated limestone of 

this region, and the ore varies in amount from a faint reddish stain to 

small areas of iron and manganese oxides quite free from calcareous 

and siliceous matter. In the Castle Hill outcrops the ore occurs as 

flattened pellets between the finely divided slate layers (see PI. 

XII, J3}. The position of the five known outcrops of this slate is on 

a line which has nearly the direction of the .general strike of the 

limestone.

1 Second Kept, on Geology of Public Lands, pp. 37 et seq.

Bull. 165 10
CHAPTER IV.

PETROGRAPHY OF THE IGNEOUS ROCKS.

o

The igneous rocks of northeastern Maine show considerable variation in composition and are represented by members of most of the 

important rock families. Abyssal rocks are not prominently exposed, 

and the number of dikes is relatively limited. The great bulk of the 

igneous occurrences are of well-marked extrusive lavas in a good state 

of preservation. The types found in this region are for the most part 

well recognized, and the classification used will require no explanation. 

Where this is not the case, the discussion of terms and variations will 

be found in connection with the various rocks described.

The subject-matter will be treated in the following order:

Granites. Mapleton granite; Drews Lake granite; dark aggregates 

in the Mapleton granite; dikes of the granite areas; metamorphism 

caused by the granites and associated dikes.

Rhyolites. Rock of the main mountain mass; white type; perlitic 

type; rhyolite-.breccia; vesicular lava.

Trachytes. Hedgehog trachyte; trachyte of Chapman Township; 

doubtful trachytes; Quoggy Joe quartz-trachyte; quartz-trachyte of 

township 9, range 3.

. Andesites. Augite-andesite; hornblende-andesite; andesites of 

southern Mapleton; andesites.of Castle Hill; andesite ash beds.

Diabase. Aroostook Falls diabase; Mars Hill diabase.

Teschenites. 1

GRANITES.

The two granite areas in this region are about 40 miles apart, and 

will be considered separately. While it seems best, from the general 

nature of the rock forming them, to call these masses granite, attention must be directed to the variable character of the composition and 

structure of the rock.

MAPLETON GRANITE.

The Mapleton granite is light gray in color, with a pinkish tinge 

given by the larger feldspars. At first sight the grain seems very 

coarse, but this appearance is caused by the presence of the larger feldspar crystals set in a medium-grained mass of dark and light minerals. 

These feldspars might almost be designated phenocrysts. Parts of

146
GEEQORY.] MAPLETON GEANITE. 147

the rock are quite marked in their porphyritic tendency. In the hand 

specimen hornblende is seen to be the most common dark mineral, and 

titanite is visible to the unaided eye. None of the minerals, except 

feldspar, are longer than 3 to 4 millimeters. From this general type the 

rock passes within a few rods into pegmatitic f acies on the one hand and 

into a fine-granular variety on the other. In places hornblende is practically the only dark mineral, elsewhere the rock appears to be an 

aggregate of mica. Sometimes quartz can not be seen in the hand 

specimen. So decided is the character of these variations that if they 

occurred as independent masses they would be classified as syenite, 

minette, etc. Numerous dark aggregates, such as are described in 

granites of other regions, occur throughout the mass. These, too, 

vary in the proportion and character of their component minerals.

In thin section, under the microscope, the Mapleton granite shows 

the following mineral composition: Iron ore, apatite, titanite, biotite, 

hornblende, oligoclase, orthoclase, including microcline, and quartz. 

. The iron is mostly included in the hornblende. The apatite exhibits 

the usual negative laths. Titanite in well-developed idiomorphic 

crystals is more common than in most granites. Biotite occurs in 

good, clear, strongly pleochroic sections or in stringy and twisted 

strands entwined with chlorite. The hornblende, like the biotite, is 

partly developed as irregular masses, sometimes radially grown, and 

partly it is the normal brown-green, pleochroic variety. The oligoclase shows Carlsbad twinning, and measurements according to the 

Michel LeVy method indicate a composition of Ab 8 An^ Orthoclase 

shows incipient kaolinization; zonal banding is conspicuous and the 

grains, are sometimes broken. Microperthite intergrowths are well 

marked in places, and again are represented by a few albite strands in 

the orthoclase. The microcline exhibits the indistinct, partly developed character more fully described as occurring in the granite and 

dikes near Ludlow. Quartz grains are usually^the broken pieces of 

larger grains and have the wavy extinction characteristic of quartzes 

subjected to pressure.

In structure these granites differ from the usual hypidiomorphic 

type. The quartz tends to be idiomorphic against the orthoclase, 

either by developing some crystal edge in the territory occupied by 

the feldspars or by sending branches into the side of the orthoclase crystals. In places several of the quartz areas extinguish simultaneously 

between crossed nicols. Throughout the whole section the feldspar 

boundaries tend to indefiniteness, and there is an approach to the conditions found in graphic granite.

The conditions of growth here indicated are different from those in 

ordinary deep-seated granitic rocks, and support the hypotheses founded 

on field observation. The porphyritic tendency is suggestive. The 

larger feldspars seem to have first formed as phenocrysts,' since they
148 CONTKIBUTIONS TO THE GEOLOGY OF MAINE. [BULL. 165.

stand out against the groundmass with distinct outline; but some of 

the feldspars must have continued to form and develop later than, or 

simultaneously with, the quartz. The micrographic intergrowth indicates an enforced, hastening of the cooling process. All these observations are in keeping with the idea that this is a small intruded mass 

whose present surface is probably not far from the original periphery. 

The presence of microcline, the numerous shattered grains of quartz, 

and the few broken feldspars all point to pressure on the mass after 

cooling.

Dark aggregates in theMapleton granite. These either take the form 

of a mass of mica shreds and plates, in which the quartz and feldspar 

is scarcely visible, or they appear as a thick sprinkling of hornblende, 

biotite, and titanite in an area of fine-grained, light-colored rock. 

They are a foot and less in diameter and are very irregular in outline.

An examination of thin sections under the microscope reveals an 

abundance of apatite columns, and especially needles. Some are as long 

as the mica laths and run through two or more minerals without a 

break. The titanite grains are eaten into and at times inclose other 

minerals. Biotite is strongly pleochroic and sometimes entwined with 

the hornblende. The hornblende is the brown-green variety, pleochroic, 

with good basal and prism sections, often grouped in masses and intergrown with or idiomorphic against the biotite. Some sections are 

bent. The feldspar, in small laths and irregular pieces, occupies bays 

in the hornblende, biotite, and titanite, or may even be idiomorphic 

against them. What little quartz is present shows a rolling extinction. 

It is instructive to note the similarity ,in composition between these 

dark aggregates and the kersantite dikes described below. It is as if a 

differentiation begun in the mass had reach reached completion in the 

associated dikes,

DREWS LAKE GRANITE.

The granite from the Ludlow quarry is considered typical for the 

Drews Lake district. It exhibits two well-marked varieties in different 

parts of the quarry. The highest rock exposed by the workmen has a 

grayish-white color in the hand specimen and its surface is sprinkled 

inconspicuously with dark specks. Quartz shows prominently and 

often forms aggregates of considerable size. In the bottom of the 

quarry the granite becomes a dark-gray variety in which the dark 

components assume a leading role and quartz is scarcely noticeable in 

microscopic examination. Transitions occur between these two types. 

While the rock differs thus widely in the relative distribution of mineral constituents, it retains a medium-grained, uniform texture, and 

the specimens at hand show no porphyritic tendency.

Under the microscope the granite from Ludlow differs from that 

from Mapleton in having the iron ore often in bundles of rods within 

the biotite, in the absence of titanite, and in the presence of a little
GEEGOKY.J DIKES IN THE GEANITE. 149

zircon. The microcline here and in the quartz-porphyry dikes of this 

district is worthy of special consideration. It is abundant, and is sometimes partly idiom orphic and distinct in character, but usually is not 

a clear-cut type and is connected with orthoclase as part, or nearly all, 

of a crystal section with no distinct line of demarcation. Sometimes 

it is intergrown with orthoclase and has distinct boundaries between 

the two minerals (see fig. 9). The structure of this granite shows the 

same characteristics as the Mapleton outcrop previously described.

The term granite is applied to these northern Maine rocks as being 

the nearest approach to the average of the typical exposures. Quartz 

is so often present in small amount and hornblende is so conspicuous 

that they might be more accurately termed hornblende-granite-syenite.

DIKES OF THE GKANITE AREAS.

Aplite occurs both on the Aroostook River and at Ludlow without 

characteristics peculiar to either locality. The rock is grayish white,

F;G. 9. Microcline and orthoclase intergrowth.

smooth, and dense. The only-minerals apparent to the unaided eye 

are pyrite and an occasional feldspar which has attained a somewhat 

 larger size than its fellows. Closer examination shows that the rare 

dark mineral is usually hornblende, that orthoclase constitutes nearly 

all the feldspar, and that the remainder is oligoclase in well-developed 

crystal sections with Carlsbad twinning. The quarts! takes its usual 

place as a cement and has a rolling extinction. Little areas of separate quartz grains extinguish simultaneously when revolved with cross 

nicols. The rock is seen to consist essentially of quartz and orthoclase 

and tends to a sugar granular structure, and hence is classed as an 

aplite.

Syenite, as reported by Professor'Bailey, 1 is found in a dike in the 

bed of the Aroostook at the base of the hill formed of the Mapleton 

granite. The rock is light gray and fairly fine grained. The dark 

components are collected in small bunches instead- of being evenly 

spread throughout the more abundant whiter minerals. The rock is 

practically quartz-free and has the characteristics of an ordinary 

syenite, being composed of orthoclase, oligoclase, biotite, and horn1 Bailey, Ann. Kept. Geol. Nat. Hist. Survey Canada, 1887-88, Pt. M, p. 46.
150 CONTRIBUTIONS TO THE GEOLOGY OF MAINE. [BULL. 165.

blende, with an abundance of pyrite. In compogition and structure 

this rock seems intermediate between the aplite mentioned above and 

the kersantite to be described later.

Grwnite-porphyry. In the railroad cuts immediately east of Ludlow 

the sedimentary rocks are cut by two classes of dikes. The first class 

includes the aplites, and the second class consists of three narrow 

dikes 10 feet, 30 feet, and 60 feet wide of a distinct type of graniteporphyry. In the hand specimen the rock appears as a mixture of 

pepper and salt in about equal proportions, in which white feldspar 

crystals have been set. These prominent phenocrysts are not crowded 

together in any part of the dikes, and usually they are separated by as 

much as their own width. No other mineral rises in size above the 

general groundmass. Microscopic examination of a thin section reveals 

the presence of biotite, hornblende, oligoclase, orthoclase, microcline, 

and quartz, with accessory iron, apatite in many minute hairlike crystals, zircon, and titanite. Biotite is mostly in shreds or laths with 

ragged edges, or in clusters and bunches, either of mica alone or

Fig. 10. Zonal intergrowth of microcline and orthoclase.

entwined with hornblende. One agglomerate composed of from twenty 

to thirty pieces of biotite is twisted and knotted together like cordsLittle loose strings of biotite are found which appear to have been 

torn off from larger pieces. The hornblende is the common green 

variety, strongly pleochroic, and occurs in short laths or in irregular 

stringy sections. The oligoclase presents nothing of special interest. 

Orthoclase, both as phenocrysts and in the groundmass, occurs as wellformed laths, simple or twinned according to the Carlsbad law. The 

larger sections especially are altered at the center to kaolin. White 

mica is also found along the cleavages as an alteration product. 

Microcline occurs in indefinite, partly developed structures in connection with orthoclase, and also as clear-cut crystal sections, with the 

characteristic cross hatching clearly defined. With the orthoclase it 

forms peculiar zonal,growths. The outside of a microcline section may 

be separated from the inside by a zone of orthoclase; or the microcline 

may be completely surrounded by a band of orthoclase. In one case 

four zones two orthoclase and two microcline must be passed over v 

in going from the periphery to the center of the crystal (see fig. 10).
GREGORY.] METAMOEPHISM. 151

Quartz is in larger grains than any other mineral except the feldspar, 

but also occurs in small grains in the groundmass. It has rolling 

extinctions and is muddied by inclusions.

Kerscmtite. This rock is found only in connection with the Mapleton 

granite area where it outcrops in the river in two dikes. One of these 

is small, the other is 500 feet or more wide. It appears as a very dark, 

stone-gray, cryptocrystalline rock with glistening surface. So far as 

can be seen without the microscope, the texture is uniform. When 

examined under the microscope a thin section shows the presence of 

iron ore, abundant apatite, biotite, hornblende, plagioclase, orthoclase, 

and quartz. Biotite is ragged and stringy, usually grouped in irregular masses, and largely altered to chlorite. The hornblende is also 

mostly changed to chlorite and is not abundant. The plagioclase is 

oligoclase-andesine with the formula Ab3An15 as shown in its extinction angles in Carlsbads by the Michel Levy method. Orthoclase is 

in almost square laths; a few show twinning. The feldspars are much 

altered and eaten into, the cavities now filled with calcite. The structure is dense granitic, verging toward porphyritic from the development of some plagioclase larger than the average.

This rock has the characteristic lamprophyric appearance, and this, 

taken in connection with the excess of plagioclase over orthoclase and 

the abundant mica, shows it to be a typical kersantite.

METAMORPHISM CAUSED BY THE GEANITES AND ASSOCIATED DIKES.

Mapleton area. The Aroostook River, where it flows through the 

townships of Washburn, Mapleton, and Presque Isle, gives a good 

section through the region affected by the Mapleton granite area. The 

outcrops along the river east of Washburn Ferry show the general 

country rock to be a black arenaceous limestone, thin-bedded, and alternating Avith beds of gritty material which under the microscope proves 

to be composed largely of broken pieces of quartz, feldspars, and calcite. 

Following the river downstream, the first marked change in the character of the rock is seen where it occurs between a dike of aplite and 

one of syenite. Metamorphism has here produced a compact schist of 

a grayish-green hue, prettily marked by a multitude of fine bands and 

lines of various shades of gray, representing the bedding planes in the 

old shale. The rock is so cut through by intersecting cleavages that 

only hand specimens can be removed. The acid test shows a very 

little lime, mostly in the white bands. With the aid of the microscope we find the main mass composed of lime garnet (grossularite), 

some pyroxene, calcite in bunches, and a little quartz and iron in a 

background of feldspar. This corresponds very well with the expected 

metamorphic changes in the gritty layers of the country rock. Side 

by side with this banded schist we find layers of impure marble which 

may represent the more limy parts of the general slates. Farther
152 CONTEIBUTIONS TO THE GEOLOGY OF MAINE. [BULL. 165.

down the river, between the, two large kersantite dikes, is a considerable area occupied by an impure, partly crystalline limestone with 

lead color and conchoidal fracture. It gives the appearance of having 

been brecciated on a fine scale and recemented. The microscope shows 

its composition to be in the main calcite, quartz, and grossularite. A 

short distance below this outcrop the immediate effects of the dike 

intrusions disappear.

The rocks adjoining the Mapleton granite are metamorphosed 

within a radius of about a mile to the southwest. The bedding 

of the original siliceous material is retained and can be easily traced 

for a considerable distance. The rock itself, however, has been 

converted into a tough, dense hornstone with conchoidal and splintery fracture. It is usually black, but at times it takes on a mottled 

gray color. In weathering a distinct white zone is produced, which 

is sharply marked off from the inside, as is common in felsitic 

rocks. The facts obtained from a microscopic examination show its 

metamorphic character and substantiate the observations made in the 

field. The sort of metamorphism here expressed and the general field 

relations lead to the conclusion that these horns£ones are the unremoved remnant of the granite cover which on Munson's farm has 

entirely disappeared.

Drews Lake area. The metamorphic rocks about Ludlow have not 

been studied in detail, but a few general observations may be made. 

Throughout the township of New Limerick metamorphic action has 

produced a hard schist marked by bands usually less than an inch 

wide which indicate the original bedding.of the rock. The strike is 

several degrees more easterly than in the case of the less altered rocks 

to the north and east, and the dip is practically vertical. The banded 

appearance is produced, in the outcrops examined, by four layers: (1) 

' a very hard, dark-blue, impure limestone, which sometimes attains a 

thickness of several feet; (2) a whitish siliceous limestone; (3) a hardened, black/micaceous slate; (4) a reddish, layer of extremely fine, 

micaceous sandstone. This last layer is not very common. At Drews 

Lake more excessive local metamorphism has produced garnetiferous 

schists, and in one case a bed of saccharoidal limestone containing 

crystals of pyrite. The intrusion of many smaller dikes and. the 

metamorphism caused by sharp folding of the calcareous strata still 

further complicate the structure in this region, and it is planned to 

devote more attention to it at another time.

RHYOLITES.

The rhyolites exhibited at Haystack, although covering so small a 

territory, exhibit great variation in composition and structure.
GREGORY.] BHYOLITES. 153

ROCK OF THE MAIN MOUNTAIN MASS.

Macroscopic description. The rock forming the main mountain 

mass appears in the hand specimen as an exceedingly dense material 

of uniform texture, having a dark-gray color with a greenish tinge. 

It is just such a rock as has been called felsite in this region as a 

field term. Under the hammer it breaks in splinters and chips having sharp, jagged edges. It breaks much more easily in some directions than in others and reveals the presence of numerous shearing 

planes along which there has been a slight movement in more than 

one direction. These small planes can usually be traced but a few 

inches and are located so irregularly that it is difficult to find a flat 

even surface of more than a square inch in area. This character is 

markedly different from the Mount Kineo quartz-porphyry, which 

microscopically it otherwise closely resembles. The more weathered material assumes a darker hue and is specked with black dots, 

which on microscopic examination are found to be alteration surrounding minute quartz aggregates. Occasional larger cavities occur 

which contain quartz crystals whose pyramid and prism faces are visible to the unaided eye. In weathering the rock forms a thin skin of 

rusty-brown material separated from the unaltered portion by a distinct boundary.

Microscopic description. Under the microscope a thin section appears at first sight as a porphyry of broken quartz phenocrysts in a 

groundmass of feldspar. Both the quartz grains and the groundmass, 

however, present peculiarities worthy of consideration. The quartzes 

are not true phenocrysts, as the following facts show. Although 

occasionally there is a small individual quartz grain located by itself, 

there are usually five to fifteen closely interlocking grains occupying 

an area in the groundmass. The larger quartz grains are nearer the 

center of the aggregate, while the smaller are found about the edge 

and adjust them selves to the shape of the cavity by filling in the recesses 

with smaller and smaller grains. Tongues and veinlets of quartz project into the groundmass, filling the little cracks which are sparingly 

distributed throughout the section, but no included fragments are 

found in the quartz, nor are reentrant bays and corroded borders seen. 

The liquid inclusions in the quartz are not evenly distributed, but 

form lines and cusps and polygons, leaving part of the grain clear. 

These geometric forms are complete within the individual grains and 

are not broken at the contact between two grains of the aggregate, as 

would be expected if one were dealing with inclusions of a phenocryst which had been shattered into fragments. Furthermore, the 

quartzes do not show the wavy extinction characteristic of rock subjected to great strain. These facts point to a secondary filling of 

amygdaloidal cavities, and the supposition is strengthened by the
154 CONTEIBUTIONS TO THE GEOLOGY -OF MAINE.

absence of areas about the quartz aggregates which are controlled by 

them in their optical orientation. The group of quartz grains themselves have no collective optical orientation. x '

Many of the quartzes are marked by a rude rhornbohedral cleavage 

such as has been described by Clements. 1 It is quite possible that the 

rhombohedral cleavage of quartz in some rock sections is formed in 

the preparation of the slide. Feldspars often have their cleavage 

cracks enlarged by grinding, and occasionally a slide shows part or all 

of a crystal torn away. Quartz can be made to cleave by the pressure of 

a sharp point on thin sections, 2 and in the sections of Maine rocks it is 

noticeable that the thicker quartzes have no cleavages developed.

The groundmass is composed of feldspar and quartz, with a little 

chlorite that is considered as replacing biotite. No other ferromagnesian minerals are present. The feldspars, with plagioclase apparently predominating, occur almost altogether as short, narrow laths of 

irregular outline that are arranged without order or tend sometimes 

to form radiate groups and flow structures. They never show a tendency to become phenocrysts. Between crossed nicols the whole 

groundmass is seen to be divided into patches which extinguish as a 

unit and then lighten as the stage revolves. It is evident that this is 

due to a micropoikilitic structure, but one which presents some variation from the usual type. The groundmass is of quartz, clear or with 

inclusions, which are arranged in areas with rude mesh structure. 

Within this groundmass the irregular laths of feldspar lie embedded 

without uniform orientation, though often many neighboring individuals extinguish alike. The quartz areas have no regularity of shape 

or 1 position or size, but extend in all directions, with recesses and 

elongated branches. The different quartz areas are connected by cross 

branches or bridged over by feldspar laths, and as the stage revolves 

one may trace a crooked course following the quartz between the little 

rafts of feldspar across the entire section. This structure is seen in 

ordinary light, but much better between nicols, especially when the 

quartz is so cut as to show its basal section.

Micropoikilitic groundmasses with similar structure have been 

recently described in rocks of a related character from Michigan and 

California. 3 The Michigamme rock which was first described is a quartzporphyry whose groundmass is almost identical with that of the rock 

from Maine, except that in the latter practically all of the feldspars are 

laths. The California (San Clemente Island) rock is a dacite and

ij. Morgan Clements, The volcanics of the Michigamme district of Michigan: Jour. Geol., Vol. 

Ill, No. 7,1895, p. 814.

2Mallard, Sur les clivages du quartz: Bull. Soc. min. de France, Vol. XIII, 1890, p. 61.

»J. Morgan Clements, op. cit., p. 814. W. S. T. Smith, Geological sketch of San Clemente Island 

(California): Eighteenth Ann. Kept. U. S. Geol. Survey, Pt. II, 1898, p. 484. See, also, Geology of Santa 

Catalina Island (California): Proc. California Acad. Nat. Sci., 3d series, Vol. I, No. 1, Feb., 1897, p. 24.
QBEGOKY.] HAYSTACK KHYOLITE. 155

shows a more uniform orientation of the feldspars than was observed 

in the other two. The characteristic features of this variety of the 

micropoikilitic structure are, feldspar laths embedded in a base of 

quartz, quartz roughly grouped into areas which extinguish simultaneously, and, within these quartz areas, the feldspar fragments without 

uniform optical orientation. If further study shows this structure to 

be of wider distribution an appropriate variety name might be useful. 

Analysis. The following analysis (I) of the rock forming the main 

mass of the mountain has been made by Dr. W. F. Hillebrand, of 

the United States Geological Survey:

Analyses of rhyolites.

Constituent.

SiO,.. . .......

ALOg---------

FeA---------

FeO.. ........

MgO .........

CaO. .........

Na,0. ........

K2 0. .........

H2 0-105°....

H2 0+105°.... 

Ti02 . .........

Zr02 .........

Cr2 03 -. .......'

V2 03 . ........

NiO..........

MnO. ........

BaO..........

SrO..........

Li20 .........

PA----------

CO, ..........

Cl...... ......

Fl...... ......

FeS2 .......'..

Total.....

i.

Per cent.

75.98

12.34

.85

.93

.15

.13

4.02

4.44

.24

.64 

.17

.03

?

Trace?

.07

Trace?

Trace?

.03

?

100. 02

II.

Per cent.

75.69

12.26

2.93

1.13-

3.01

4.74

'

.06

99.82

III.

Per cent. 

74.90

13.64

.66

.50

.61

4.22

4.64

.33

.15

Trace

Trace

'

99.65

IV.

Per cent. 

75.20

12.96

.37

.27

.12

.29

2.02

8.38

.58

.03

Trace.

100. 22

V.

Per cent. 

75.31

12.96

3.05

5.11

3.15

.61

.41

.05

100. 65

VI.

Per cent. 

77.28

11. 24

1.74

None.

.21

Trace.

3.10'

4.55

1.16

Trace.

.02

99.47

I. Rhyolite, Haystack Mountain, Maine. Analysis by W. F. Hillebrand, United States Geological 

Survey.

II. Rhyolite, Rescue Canyon, Nevada. Analysis by R. W. Mahan. Hague, Geology of Eureka district: Mou. United States Geological Survey, Vol. XX, p. 2C4.
156 CONTRIBUTIONS TO THE GEOLOGY OF MAINE. [BULL. 165.

III. Rhyolite, Castle Mountain, Montana. Analysis by L. V. Pirrson. Weed and Pirrson, Geology 

of Castle Mountain mining district: Bull. United States Geological Survey No. 139, p. 120.

IV. Rhyolite, Round Mountain, Colorado. Analysis by L. G. Eakins. Cross, Geology of Silver Cliff 

and Rosita Hills: Seventeenth Ann. Rept. United States Geological Survey, Part II, p. 324.

V. Aporhyolite (Laminated orthofelsite), South Mountain, Pennsylvania. Analysis by F. A. Genth. 

Second Pennsylvania Geological Survey, Vol. CCC, p. 265. Recognized as aporhyolite by F. 

Bascom, Bull. -United States Geological Survey No. 136.

VI. Aporhyolite, Fox Islands, Maine. Analysis by E. W. Magruder and W. A. Jones. G.jO. Smith, 

Geology of Fox Islands, Maine. Presented as thesis at Johns Hopkins University; printed 

privately. ' '

The analysis (I) shows the Haystack rock to belong to the alkaline 

series of rhyolites, and a comparison with the other analyses presented 

(II-VI) shows it to differ in no important particular from typical 

modern and ancient rhyolites of other regions. As the microscopic 

examination indicated, the components present must be practically 

quartz and alkali feldspar. The percentages of the different minerals 

have been calculated from the analysis as follows:

Mineral.

Quartz .................

Orthoclase ..............

Albite. ....... ..........

Chlorite ...........*....

Kaolin .................

Titanite . ...............

Total.............

Per cen t.

. 34.1

26.2

34.1

2.7

4.

.4

.5

100

WHITE TYPE.

Near the base of the hill the rhyolite, while retaining the felsitic 

appearance of the main mass, becomes white in color and does not 

break into such keen-edged chips. The quartz aggregates filling the 

flattened cavities are easily seen in the hand specimen. The weathered 

rock is yellow-brown and shows numerous narrow,- troughlike cavities, at times becoming a quarter of an inch long and lined with small 

quartz crystals of secondary origin.

The microscope reveals a structure of the same character as that found 

in the rock from the top of the hill. There are no phenocrysts of 

feldspar, and the pseudophenocrysts present are formed of aggregates 

of from 10 to 20 quartz grains, each of which retains its crystal outline in some degree. As a rule, these aggregates have.a large piece at 

the center, occupying perhaps one-half the space, and this piece is 

surrounded by smaller pieces, while still smaller fragments fill the 

irregular spaces next the cavity wall. The boundaries between the 

quartz grains are clear-cut lines, which often project into each other
GEEOORY.] - TYPES OF EHYOLITE. 157

by sharp angles. Usually two or more pieces situated near each other 

extinguish together. The groundinass is of quartz and feldspar, with 

the type of micropoikilitic structure described above.

The light-colored rhyolite at times takes on a peculiar structure, 

which is well brought out in weathered specimens. The vesicular 

cavities take the form of narrow tubes 1 to 3 inches long, all of which 

run parallel, the parallelism presumably having been caused by the 

flow of the rock, whereby the vesicles have been drawn out into long 

canals. When the rock is broken, so as to give a cross section of the 

tubes, the appearance is strikingly like that of a cross section through 

an endogenous plant, which shows the fibrovascular bundles arranged 

without order. The longitudinal section, however, exhibits long, narrow slits or troughs, sometimes lined with secondary quartz crystals, 

which give the appearance of birch bark. The color and the selective 

effects of weathering make the likeness still more evident (see PL VI).

PEKLITIC TYPE.

Within the space ,of an inch the white aporhyolite is replaced by a 

rock of an entirely different type one which microscopically appears 

like perlite. Neither in the hand specimen nor under the microscope 

does the contact zone show any sudden change from one facies to the 

other, and it almost seems as if the whole effect was due to weathering, 

and yet the rocks are entirely distinct in structure.

Macroscopic description. Examination of the hand specimen reveals 

a mass of spheres 1 to 5 millimeters in diameter, composed of a grayish-green substance with interstices filled with the same material. In 

the fresher parts the spheres remain in the mass and are broken across 

by a fracture of the rock, revealing centers filled with a shining greenblack substance. Where the rock is more weathered the spheres are 

loosened and readily drop out. When a thin section is viewed without the aid of a microscope the spherule structure is clearly seen, 

especially when brought out by weathering. The spheres not always 

round in section are bounded by a brown glassy substance, and the 

interspaces are seen not to differ in appearance from the material 

forming the spheres except that they are more altered. The centers 

of the spheres often contain quartz grains and an area made up of 

chlorite and delessite (see Pis. V, A and XIII, A).

Microscopic description. Microscopically examined, the thin section 

reveals no smaller spheres than were seen with the naked: eye. The 

centers of the spheres are found to be oblong or elliptical cavities 

wholly or in part filled as follows: A few quartz grains showing crystal outlines and marked by inclusions and a rude rhombohedral cleavage project into the cavity. Surrounding the quartzes as a fringe, 

and extending as a zone all around the cavity, is found a brownishgreen mineral, probably delessite. The center of the cavity is filled
158 OONTBIBUTIONS TO THE GEOLOGY -OF MAINE. [BULL. 165.

with chlorite in bundles and radial growths. Combinations of chlorite 

and delessite form beautiful rosettes and colored vermiculate bodies. 

Limonite is also present in formless masses. The alteration products 

so well exhibited in the cavities are distributed as dots and little masses 

more or less abundantly throughout the section.

The groundmass is glassy. In places it is entirely amorphous; elsewhere minute feldspar laths lie in an undifferentiated background, and 

in still other places the feldspars lie in small areas of quartz with a 

structure which approaches the micropoikilitic. The glassy groundmass is crowded with crystallites which assume ordinarily rodlike or 

needlelike forms, but which also occur branched or crossed, and in rare 

instances form a radial structure resembling the spokes of a wheel. 

Around each of these crystallike bodies is a colorless zone, indicating 

that the rodlike growth has been built up at the expense of the surrounding part. The substance which composes the rod and the dark 

parts outside the colorless zone is of the same composition. In the section examined this. material is found to be. largely chlorite, but from 

the shape of the rods and the character of the alteration it is judged to 

have been mostly biotite. The clear zone surrounding the crystallites 

appears in ordinary light as.a light-yellow glass from which the dark 

components have been absorbed to make the center rod. Between nicols 

the glass is found to be partly devitrified, revealing numerous little 

feldspar laths in the glassy base. It is evident that the rock section 

presents the same general appearance under the microscope as when 

fresh and that it is made up of grains and partly formed crystals of 

f erromagnesian minerals in a vitreous groundmass. The minerals have 

altered in composition and the glass is in part devitrified, but the type 

of structure remains unchanged. The appearance of the rodlike bodies 

surrounded by a clear space is seen only in ordinary light. In polarized light nothing appears except the feldspars in their quartzose and 

glassy base. . The accompanying figure (PL XIII, B) will illustrate the 

points discussed above. .

EHYOLITE BRECCIA.

Macroscopic description. Near the southeast base of Haystack, on 

the north side of a slight rise of ground, a few small masses of porphyritic breccia are found. The hand specimen shows a greenish-black 

rock with small, waxy-looking feldspar phenocrysts, which differ little 

in color from the main groundmass, but are noticeable for their lustrous 

reflection on cleavage surfaces. Distributed thickly through the porphyry are irregular angular fragments of a pitchstone, which at times 

are as large as 3 to 4 inches in diameter. For the most part these 

glassy chunks have an oily-looking surface of .various shades of dark 

green. They are much cut up by a series of fractures, so that under 

the hammer they are broken into little irregular chips. At times the 

pitchstone assumes various shades of red.
U.S.GEOLOGICAL SURVEY BULLETIN NO.165 PL. XIII

f At PERLITIC TYPE OF RHYOLITE. 

(S) AREA BETWEEN SPHERULES , PERLITIC TYPE OF RHYOLITE.

THE HELIOTVPE PRINTING CO., BOSTON.
GREGORY.] RHYOLITE BRECCIA. 159

Microscopic description. The microscope brings out the porphyritic 

structure well and reveals the presence of phenocrysts of orthoclase 

and oligoclase. Quartz and an undetermined mineral are present and 

rise in size above the general groundmass. Apatite occurs in long 

needles, which are broken and thrown out of alignment. . The groundmass varies in character with the fragments of the breccia. The orthoclase phenocrysts occur as plain laths of a somewhat square shape or 

as twins or basal sections nearly always with good crystal outlines, 

but they also occur with rounded edges or inclosed by a distinct zone 

of alteration. The oligoclase' phenocrysts are fewer in number than 

the orthoclase, but exhibit the same general features. The feldspars 

measure 2 to 5 millimeters in length and are broken along lines where 

the pressure has been relieved. Alteration to kaolin and sericite has 

progressed so far that no clear pieces remain. Another mineral about 

one-fourth the size of the feldspar phenocrysts is abundant in the 

slide in limited areas. It is yellow-brown in color where freshest, but 

changes with different stages of alteration to a lavender-gray. Its 

shape and cleavage suggest a tetragonal mineral, and the high colors 

shown by double and single refraction suggest one of the rare accessory minerals rutile, zircon, or cassiterite. The polarization is given 

by an aggregate of grains, and the present altered state makes accurate 

determination impossible. The chunks of rhyolite pitchstone embedded 

in the mass yield a small amount of water in the closed tube and 

show a partially devitrified structure under the microscope. Small 

aggregates of quartz grains, now occupy areas and cracks which appear 

to have been cavities that were filled by the quartz at a later date.

Some fragments of the breccia have a groundmass composed of 

quartz and feldspar grains and laths arranged in well-developed flow 

structure. The streams separate to flow around the phenocrysts, then 

reunite beyond. Other portions of the breccia show a considerable 

portion of partly devitrified glass in their groundmass, especially 

when the section is cut through the included glass fragments seen so 

prominently in the hand specimen. In one place a group of lathlike 

feldspar phenocrysts is found with the interstices occupied by altered 

glass, thus imitating the structure found in some diabases and termed 

mesastasis by Roseribusch. Chlorite is now an abundant secondary 

product throughout the whole rock.

. VESICULAR LAVA.

About three-fourths of a mile east of Haystack are a few scattered 

hummocks of coarsely vesicular lava. The surface exposure is of a 

rusty yellow rock, from which project angular knobs formed by 

weathering along" the cleavage cracks. These cleavages are very 

numerous and intersect at all angles.
160 CONTRIBUTIONS TO THE GEOLOGY OF MAINE. [BULL. 165.

Macroscopic description. When a hand specimen is broken from the 

ledge, attention is at once called to its spongy appearance, which suggests furnace slag coated with iron rust. - This porosity is caused by the 

presence of cavities which average about 1 millimeter and are so numerous as to form nearly half of the rock. Examination of fresher 

material shows that it has an ashy-gray color and dense texture, and that 

the oval cavities which in the surface exposure were empt}^ are here 

filled with black and white calcite. The cleavage cracks are also filled 

with calcite. These vesicles may be so broken as to show in cross section, or they may retain their identity and remain on the surface as 

projecting spheres (see PI. V, J3).

Microscopic description. When a thin section is studied the vesicles 

present the most prominent appearance. They are i to 3 millimeters in 

diameter. The smaller ones are usually round, others are oblong, 

while many have a wavy outline formed by several neighboring bubbles whose inside division walls have been broken down. The boundary of the cavity is marked by a dense substance, probably a glass 

blackened by ferritic material, and the cavities are lined with a layer 

of impure fibrous calcite, which may be a mere film or ma}' fill half 

the space. Three or more concentric layers may form the lining, and 

one or more of them may bulge out to form little bays. The lining is 

often broken, and fragments have become entirely detached and drop in 

toward the center. Sometimes the cavity is half, or even entirely, 

filled with these fragments. Areas are found where the single cavities 

are replaced by a group of minute vesicles which have a definite 

boundary. These cavities are now entirely filled with calcite. The 

feldspar laths of the groundmass are crowded together and arranged 

in a rudely concentric manner about the vesicles. The form and 

structure of these cavities are shown in PI. XIV, B, and aresxplained as

follows: The water contained in the rock was driven out by the crystallization of the magma and was free to act mechanically as steam. 

Centers of accumulated steam formed the cavities and have left the 

feldspars in their wreath arrangement. The lining of one or more 

concentric layers of impure iron and lime compounds was then formed. 

Some slight jar then produced the few cracks and broke down the lining of the tiny geodes. The' rock shows no effects of outside strain 

except these broken vesicles, and the effects just mentioned may be 

due to the action of the solution within the cavity itself. Finally, 

infiltrated calcite has filled all the broken cavities and cracks, and is 

the most prominent mineral seen under the microscope as well as in 

the hand specimen. . .

The general groundmass is trachytic, and is composed of quartz 

grains and feldspars with a few large apatites. The feldspars are 

apparently about half plagioclase and half orthoclase, and occur mostly 

in delicate shreds, sometimes thirty times as long as broad. The ends
U.S.GEOLDGICAL SURVEY BULLETIN NO. 165 PL.XIV

VESICULAR LAVA. 

VOLCANIC TUFF.

THE: HELIOTVPE PRINTING co.. BOSTON.
.GREGORY.] TRACHYTES. 161

are split and uneven and at times become merely a bundle of fibers, 

while little branch threads cling to the sides of the shreds. Sometimes straight feldspars are seen, but more often they are bent orcurved so much as to form a half circle. Besides the expansion structure so well exhibited about the vesicular cavities, parts of the slide 

show a well-developed flow structure. The rock is plainly a vesicular 

rhyolite lava with dacitic facies.

TRACHYTES.

Under this head will be described all the rocks of this region whose 

principal component is alkali feldspar, whether they occur as extrusive 

volcanics or as intrusive masses or dikes. For the purposes of this discussion they will bee grouped as trachytes, doubtful trachytes, and 

quartz-trachytes.

HEDGEHOG TRACHYTE.

The specimens of this rock found in place are all from the cliffs and 

sharp comb at the very highest points on the mountain, but there is 

reason to believe that they fairly represent the whole mass. When 

seen in the ledge the rock appears as rough tabular blocks formed by 

intersecting cleavages. The color is very light gray on the more 

exposed surfaces and a rusty iron brown in the narrow cracks, but a 

blow of the hammer shows that this outer weathering is scarcely 

thicker than a coat of paint, and that the fresh rock is bluish gray in 

color, Avlth a mottled appearance. The general texture is fine, uniform, 

not at all porphyritic, and, at one point on the mountain, slightly 

brecciated. The whole rock, however, contains abundant vesicular 

cavities, round or oval in shape, and varying in size from a pin head 

to a quarter of an inch in diameter. These cavities are usually filled 

with quartz, occasionally of the amethyst variety, and some contain a 

glistening white calcite. The rock is now thoroughly silicified, and 

the cavities and minute cleavages and fissures are filled with firm 

cement that in weathering melts down only as fast as the original 

material, or even more slowly, so that occasionally a quartz-filled veinlet projects slightly above the general level of the weathered surface. 

The rare empty cavities found in the altered portions were probably 

filled with calcite.

The microscope reveals a rock made up of quartz-filled vesicles in a 

groundmass of feldspar laths. The quartz filling the cavities is composed of many grains, jagged and .branched, with no optical orientation 

as a group, and only rarely containing inclusions. The minute fissures 

are filled in the same manner, and all the facts point to a secondary 

origin of the quartz. The sections of feldspar shown in the slide vary 

in form from, long, rodlike shapes to squares, but the greater number 

Bull, 165 11
162 CONTKIBUTIONS TO THE GEOLOGY OF MAINE. [BULL. 165.

occur as rectangles three or four times as long as broad, which present 

clear-cut outlines and do not 1 show the ragged, stringy, thunderbolt 

 forms found in the Chapman trachyte and the andesite from Edmunds 

Hill. No dark-colored mineral appears in the rock, and the chlorite 

present in considerable amount gives no clue as to the mineral jt has 

replaced. The groundmass is arranged with remarkably good flow 

structure. Practically all the feldspar microlites are arranged with 

their longer axes parallel, and the streams which they form are seen 

to divide in order to pass around the quartz-filled vesicles and then to 

reunite beyond. The section examined contains a fragment of a somewhat different igneous rock, which, judging from the manner in which 

the lava has flowed about it, appears to have been dropped into the 

lava flow while in motion.

o 

TRACHYTE OF CHAPMAN TOWNSHIP.

Macroscopic description. When seen in the ledge the appearance of 

this rock is very deceptive. It has there a brownish-black color, 

smooth feel, and presents little tables with angular outlines rather 

than round-cornered fragments. However, when the rock is broken, 

so as to expose fresh material, the brown color and smooth feel are 

seen to be confined to a very thin layer on the outside, while the main 

mass has a very light-gray color with a bluish cast and a rough feel, 

and breaks into sharp, irregular chips. In general the rock is dense 

and uniform and specked with minute black dots, which at times are 

large enough to be distinguished as cavities with black lining. Feldspar crystals, stout, or more often long and very narrow, are scattered 

inconspicuously through the mass, and would be scarcely noticeable 

except for their glistening cleavage faces. The' whole rock is marked 

by numerous slits or flat, slender cavities, short and small, but sometimes half an inch in length. Their longer axes are parallel to one 

another and approximately horizontal. These slits represent the cavities of a highly vesicular lava which have been drawn out from their 

spherical shape by movements of flow.

The cavities are now usually empty, being only lined with a rustyyellow substance, but some of the larger ones are filled with calcite or 

quartz. So distinctly trachytic is the rock in its general appearance 

and decided flow character that from an examination of the hand specimen alone one feels safe in designating it a feldspathic lava.

Microscopic description. Under the microscope a few feldspar 

phenocrysts and patches of chlorite are seen to lie in a groundmass 

of feldspar laths. Quartz is also present. The larger feldspars are so 

cut in the section as to show squares, or, more often, narrow laths half 

a millimeter long. Carlsbad twinning occurs with irregular division 

line between the two halves, and from this line tongues of one twin
GREGORY.] TRACHYTE OF CHAPMAN TOWNSHIP. 163

project to a considerable distance into the other. One section shows 

a partly developed microperthite intergrowth. All these larger 

unstriated feldspars are of the clear sanidine variety and have much 

the appearance of quartz; their edges and crystal outlines are well 

preserved, and only rarely are they altered or muddied by inclusions. 

Judging from the analysis, these are probably soda orthoclases. Next 

to the feldspars, patches of chlorite occupy the most prominent place 

among the larger minerals. The chlorite is surrounded by a clear 

zone, which between nicols is seen to consist of feldspar laths. The 

arrangement of the groundmass points to the former presence of 

a mineral which has been replaced by ^the chlorite. From the shape 

of the chlorite areas, and because of the absence of any carbonates 

among the alteration products, which might have been expected if 

the original mineral had been hornblende or augite, this mineral is 

believed to have been biotite. A few pieces of an altered brownishgreen mineral may be biotite, or possibly hornblende. A little secondary quartz, with indications of rhombohedral cleavage and clouded by 

inclusions, fills a few cavities and cracks in the rock.

The groundmass is composed of stringy, ragged feldspar microlites, 

often bent and curved. The feldspars are largely untwinned, although 

Carlsbads are found with the halves unevenly developed. Among the 

plagioclases sections were found with both Carlsbad, and albite twinning, which made possible their determination as albite by Michel 

LeVy's method. When viewed with a low power the groundmass 

shows a general flow structure in the longitudinal direction of the 

flattened vesicles; but under higher powers the fluxional character is 

not very conspicuous, even around the larger feldspars. Yellowish 

cryptocrystalline aggregates found sparingly in the section may be 

devitrified glass. At present the whole slide is sprinkled with minute 

greenish-yellow dots, which may be considered as representing grains 

of some ferromagnesian mineral.

Analysis. The alkalies present in the rock were determined by Dr. 

C. H. Warren, of the Sheffield Scientific School, and found to be: 

CaO, 1.06; Na2O, 8.75; K2O, .20. The trifling amount of potash was 

unexpected, and to guard against error a second determination was 

made, but with the same result. As the analysis shows, soda is the 

predominating alkili, and it must be the chief component of the feldspars. The rock itself falls into the group of soda trachytes or keratophyres.

Rocks of this group are rare in America, and for this reason they 

are interesting and worthy of considerable attention, even though their 

field occurrence has not been worked out in detail and complete analysis has not been made.
164 CONTRIBUTIONS TO THE GEOLOGY OF MAINE. [BULL. 165. 

DOUBTFUL TRACHYTES.

Specimens of a trachytic-looking rock were collected on the South 

Branch of Caribou Stream in Woodland Township. The specimens 

have a fresh appearance and present two varieties. The greater part 

is a dense, bluish-gray rock, uniform in color and texture, and easily 

broken into any desired shape, while the other variety differs only in 

the presence of vesicular cavities i to '2 millimeters in diameter, which 

constitute nearly one-third of the whole mass. These two rock types 

are different parts of one lava flow of uncertain size. The cleavage 

cracks and cavities are now filled with calcite.

The microscope reveals an advanced state of alteration not suggested 

by the hand specimen, and the minerals can not be determined with 

certainty. The vesicles are found to be present in the dense variety 

also, differing from the others only in size. They are generally round, 

with a border of fine, fibrous calcite and chlorite alterations, and filled 

with chlorite or calcite. The groundmass, so far as can be read through 

the extensive alteration to carbonates, is of bent or curved orthoclase 

laths, which are long and narrow, with irregular outline, frayed-out 

edges, and ragged ends. The ferromagnesian minerals have entirely 

disappeared. The groundmass is trachytic in structure, with poorly 

developed flow structure. All that can safely be said of these rocks is 

that they are parts of a vesicular lava flow, probably belonging to the 

trachyte group. -

QUOGGT JOE QUARTZ-TRACHYTE.

Macroscopic description. The entire mass of the Quoggy'Joe group 

of hills is of this material, and the drift bowlders and widespread 

talus make it a very common field rock over a large area. It presents 

various aspects, owing to its state of alteration, but is easily distinguishable from other rocks of the region by its white color when broken 

and by its method of weathering. The freshest material was found 

on the summit of the hill, where it has a whitish-gray or yellowishchocolate color and is very dense and felsitic in appearance. The 

whole mass is cut by cleavage planes, and under the hammer a hand 

specimen breaks into rudely rectangular blocks, indicating numerous 

inconspicuous cleavages or planes of weakness. The fracture is uneven, 

and exposes a rough, trachytic surface with a certain silky sheen. The 

whole rock, weathered and fresh, is spotted with minute black and 

brown dots, which prove to be iron ore and alteration products.

Besides the planes of fracture spoken of, the rock shows many little 

long and exceedingly narrow cavities arranged in parallel rows, which 

seem to indicate stress insufficient to form complete cracks, but which 

may represent original vesicles drawn out by flow or shearing. These
GREGORY.] QUOGGY JOE QUARTZ-TRACHYTE. 165

slits are prominently brought out by weathering, and occasionally they 

are lined or even filled with quartz grains.

Surface alteration takes the form of a thin brown coat, which forms 

a sudden and conspicuous change from the white rock beneath. In no 

case does this outer coating exceed one-eighth of an inch in thickness, 

and there is never a gradation from the weathered part to the unaltered 

inner material, but immediately inside the brown coating the rock is 

as light colored and apparently as fresh as at the very center of the 

specimen. The cross section of a white block which had been painted 

black would show no more marked and sudden contrast between the 

wood and the paint than is exhibited in the weathering of specimens 

from Quoggy Joe. This distinct method of weathering is everywhere 

an important characteristic of rocks of this type, and is very useful in 

field determination, Occasionally this coating is stained with a shining blue-black manganese-bearing material.

Microscopic description. -The microscope reveals a rock composed 

of iron ore, albite, orthoclase, and quartz, with siderite, kaolin, and 

chlorite as decomposition products. The quartz is the only mineral 

which rises above the fine groundmass, and occurs as groups of grains 

usually surrounded by the iron carbonate. The individual grains are 

very irregular in their outline, and, as noted in the rhyelites, the 

groups have no common orientation. That some of the quartz is secondary is indicated by the fact that it fills minute cleavage cracks 

which traverse the rock in all directions, and is most abundant in the 

little,slitlike cavities connected by these cracks. The slits noticed in 

the hand specimen are found to be arranged along lines now filled 

with quartz grains, and are understood to be local enlargements of 

imperfect cleavage and to have been formed by a stretching due to 

unequal movement and pressure.

The groundmass is composed of small, narrow feldspar microlites, 

arranged with typical trachytic structure, together with a great deal 

of quartz in finely divided particles. The feldspars are not easily 

determined, but they show many Carlsbad twins and albite twins, and 

these facts, taken in connection with their average extinction angle of 

17°, indicate orthoclase and albite or andesine, but the small amount of 

lime, as' shown by the analysis; would prevent the formation of andesine, -and leaves albite as the probable plagioclase. The carbonate 

occurs in patches throughout the section, but is particularly abundant 

surrounding the partly quartz-filled cavities. Magnetite is found in 

specks and srnaj'l dust aggregates, and the chlorite occurs in such forms 

and positions as to give no clue to the former mineral which it now 

represents.
166 CONTRIBUTIONS TO THE GEOLOGY OF MAINE. [BULL. 165.

Analysis. The following analysis (I) of the freshest material 

obtained was made by Dr. W. F. Hillebrand, of the United States 

Geological Survey:

Analyses of quartz-trachytes and bostonites.

Constituent.

SiO,.. ........

AI n

Fe2 03 ........

FeO..........

MgO. ........

CaO..........

Na,0.. .......

K20. ---------

HjO-1050 .... 

H20+105°.-.. 

Ti02 ... .......

Zr02 .........

CrA---------

VA ---------

NiO.. .........

MnO. ........

BaO .........

SrO ..........

Li2 0.. ........

PA----------

C02 ..........

01...... ......

Fl. ...........

FeS2 ........

Total.....

I.

Per cent.

72.77

12.15

.44

3.06

.22

.07

3.38

4..G7

.17 

.55 

.20

.04

None.

?

None.

.16

.03

None.

?

Trace.

2.06

?

?

( (.0678)

I .12

100. 09

n.

Per cent. 

70.23

15.00

1.99

Undet.

.38

.33

4.98

4.99

.91 

1.28 

? . 03 .

.24

.06

\

100. 42

III.

Per cent. 

69.00

13.95

1.56

2.38

.14

.49

5.67

5.11

| .70 

 .35

.55

'

99.95

IV.

Per cent. 

62.30

17.05

1.30

2.46

.57

1.20

5.14

6.18

'.45 

Trace.

Trace.

2.65

.43

99.73

V.

Per cent. 

62.28

19.17

3.39

Trace.

1.44

5.37

5.93

2.33

99.91

VI.

Per ceiiL 

72. 88

12.90

.74

1.05

.75

.81

3.72

5.03

1. 22

.45 ;'

.05

99.60

I. Quartz-trachyte, Quoggy Joe Mountain, Maine. Analysis by W. F. Hillebrand, United States 

Geological Survey.

II. Bostonite (trachyte, keratophyre), Marblehead Neck, Massachusetts. Analysis by T. M. Chatard. 

Sears, Bull. Museum Comp. Zool.Harvard Coll., Vol. XVI, No. 9,1890, p. 170.

III. Quartz-bostonite (quartzlindoite) Hof. Fron. Tartberg, Christiania, Norway. Analysis by U. 

Schmelck. Brogger, Eruptivegesteine.des Kristianiagebietes, Grorudit-Tinguaite-Serie, p. 139.

IV. Quartz-bostonite (lindoit). Gjefsen Kirchspiel Gran. Norway. Analysis by L. Schmelck. Brogger, Eruptivegesteine des Kristianiagebietes, Grorudit-Tinguaite-Serie, p. 139.

V. Bostonite, Lake Champlain. Analysis byKemp. Bull. U. S. Geol. Survey No. 107,1893, p. 20.

VI. Aplite-granite dike, Castle Mountain, Montana. Analysis by Pirsson. Weed and Pirsson, Bull. 

U. S. Geol. Survey No. 139,1896, p. 96.

Discussion of analysis. This analysis shows some facts worthy of 

fuller mention. The carbonate present in such large quantity must
GREGORY,] QUAKTZ-TKACHYTE. 167

be almost entirely ferrous carbonate, as is common in rocks of this 

type. 1 It will be noticed that if a series of rocks of this type is to be 

constructed from comparison of the analyses, the Maine rock is the 

most acid type so far described, although some silica should be deducted 

for the secondary quartz present. The chemical composition of the 

quartz-trachyte differs little from that' of the rhyolites (see p. -155), 

but the appearance of the two hand specimens is distinctly different. 

The aplite-granites (VI) have also much the same composition, but 

their structures, both macroscopically and microscopically, show characteristic differences.

The percentages of mineral components present in the Quoggy Joe 

quartz-trachyte have been calculated from the analysis and found to 

be as follows:

Mineral components of Quoggy Joe quarts-trachyte.

. Mineral.

Albite...... ............

Percent.

34.97

27.86

30.46

3.88

Mineral.

Kaolin .................

Chlorite ................

Iron ore, etc ............

Total ...............

Fur cent.

1.66

.50

.44

99.77

Classification. The term which should be applied to a rock of this 

character is not clearly evident. It belongs, however, to that variety 

of trachyte found in many places which is characterized by a white or 

creamy color, rough trachytic surface and appearance, a peculiar silky 

sheen, and a distinct mode of weathering. By this mode of weathering, which is rare for ordinary flow trachytes, but very characteristic 

for quartz-trachytes, the rock does not show gradations from weathered to fresh surface, but shows a thin dark outer zone which is 

suddenly replaced by the fresh white material within. Furthermore, 

so far as alterations can be considered characteristic, it is marked 

by the presence of siderite in place of calcite. Its microstructure is 

also characteristic in that it retains a typical trachytic structure of 

feldspar laths whose interspaces are filled with quartz, and not the 

granular structure common in alkaline rocks so full of silica. Hunter 

and Rosenbusch named rocks of this habit bostonite, 2 thus distinguishing a new class of dike rocks, and taking'the Marblehead Neck outcropas the type, although at that place it is apparently a surface flow. 

Chemically and mineralogically bostonites are practically trachytes, 

except that soda orthoclase is unusually abundant and the dark silicates are very few or are altogether lacking.

 'Brogger, Das Ganggefolge des Laurdalits, p. 201. 

a Tscher. Min. u. Petrog. Mitth. 1890, p. 447.
168 CONTRIBUTIONS TO THE GKEOLO&Y OF MAINE. [BULL. 166.

While the Maine rock has the characteristics of bostonites, it does 

not seem wise to' enlarge the scope of the term, especially since its 

presence in petrographic nomenclature is of doubtful utility. The term 

quartz-trachyte is therefore used to denote the trachytic character of 

the rock under discussion and at the same time to indicate the high 

percentage of silica.

QUARTZ-TRACHYTE OF TOWNSHIP 9, RANGE 3.

The rock at this place is easily separated into blocks along the lines 

of fracture, which intersect one another at small angles. Examination 

of one of these small blocks shows a very dense yellowish-white material with a somewhat glistening surface. Within this felsitic groundmass are many specks of quartz about the size of a pin head, and 

a few larger cavities which are filled with quartz and carbonates, 

forming creamy-white areas with sparkling grains. Quartz also 

fills the minute cracks that are visible, and so secure is the cement 

that the rock is more easily broken in other directions than along 

these reunited fractures. In weathering, a rusty-gray zone about 

one-half inch thick is formed in which the cavities are filled with a 

yellow powder.

The minerals in a fresh specimen, as revealed by the microscope, 

are apatite, plagioclase, orthoclase, and quartz, together with muscovite, siderite, limonite, and a little calcite. The quartz forms perhaps one-third of the section and occurs as cement, closing fractures 

and filling in the spaces in the groundmass. The grains are usually 

broken into rude rhombs, and contain, as inclusions, numerous long, 

slender needles of apatite, together with occasional liquid inclusions. 

The feldspars form slender laths and a few square sections and are confined to the groundmass. The striated pieces about equal the unstriated in number, and since sections-cut parallel to 5 can not show albite 

twinning, there is probably an excess of plagioclase over orthoclase in 

the section. By averaging many extinction angles the plagioclase was 

determined as oligoclase albite. Microperthite intergrowths occur. 

Muscovite forms part of the alteration products, and shows the cleavage and surface structure characteristic of micas, and also shows a very 

faint difference of absorption. The siderite and calcite are found in 

patches throughout the rock, while limonite forms the yellowish specks 

fso prominent in the more weathered portions/

The structure of the groundmass is trachytic, although somewhat 

more granular than the Quoggy Joe specimen; quartz also takes a 

more important place among the feldspar laths.

ANDESITES.

Generally speaking, the andesites of this region belong to well-recognized varieties widely distributed over the earth, and differ in no
GREGORY.] ANDESITES. 169

important particular from the type rocks of their class. Varieties are 

found here, however, which are intermediate between andesites and 

trachytes, and some with dacite facies are also found. The exposures 

are numerous and easy of access, and the specimens are no more altered 

in composition than if they were lavas of Tertiary age instead of 

Paleozoic.

AUGITE-ANDESITE.

Macroscopic description. The largest and best single exposure of 

andesite in this region is of the augite-andesite variety, and forms the 

main mass of Edmunds Hill. It does not occur as a solid, compact 

mass at any part of the hill, but is broken by cleavage and shearing 

planes into large blocks on top, and into plates and slated material at 

the ends of the hill. This slated and seemingly bedded appearance, 

which is so unusual in an igneous rock, is the most marked peculiarity 

of the structure of the hill. In a few places the rock is seen to contain embedded angular pebbles of glass and baked siliceous material, 

which stand out when it weathers; and in other places the rock presents a banded surface of gray and brown, which gives the appearance of bedding, but which proves on examination to represent varying stages of decomposition along potential cleavages. With these 

exceptions the exposed rock has a uniform appearance, gray where 

weathered, black where fresh.

Andesites are such well-known rocks that an extended macroscopic 

description is unnecessary. The hand specimen appears as. a black, 

basaltic-looking rock, generally dense, with a stringy effect and 

sprinkled over with glassy feldspars 2 millimeters and less in length. 

The weathered surface is a layer of spongy, gray-brown material, in 

which the pores are made by the decay of the larger feldspars. At the 

east end of the hill the rock is much lighter in color, and numerous 

white feldspars give it a more porphyritic appearance.

Microscopic description. Microscopic examination reveals the composition and structure expected of a typical andesite. Magnetite, apatite, pyroxene, plagioclase, and orthoclase are the original minerals 

present. The plagioclase crystals range in size from laths 2 millimeters 

in length down to the very fine ones in the groundmass, but the larger 

' ones are not abundant and do not give the rock a porphyritic aspect. 

The plagioclase forming the crystals outside the groundmass was 

determined by Michel LeVy's method to be labradorite; but the 

measurements indicated two labradorites, with the foruiulse Ab3An4 

and AbBAn6 . The larger feldspars show strongly marked zonal banding, with occasionally as many as eight distinct zones, which decrease 

in basicity from the center outward, but with tne original albite twinning running through the whole series. This albite twinning shows 

in nearly every feldspar lath with great distinctness, and twins on the
170 CONTRIBUTIONS TO THE GEOLOGY OF MAINE. [BUM, 165.

pericline and Manebach laws also occur. The Carlsbad twins present 

are often with one half dropped much below the other, and all the 

twinning is more or less along irregular ragged lines and with unsymmetric development. None of the feldspars are entirely fresh, but 

are kaolinized along the cleavages and zonal boundaries, or are entirely 

altered to kaolin and calcite except upon their outer borders. They 

also show irregular cracks other than cleavage, along which strain has 

been relieved. Glass inclusions, arranged without order, are numerous and stand out prominently in the clearer parts of the feldspars. 

Orthoclase was not found outside the groundmass, except as forming 

the wide outer rim of the zonally built plagioclases.

The pyroxenes are of both monoclinic and orthorhombic varieties. 

The monoclinic is an augite, light colored in thin section, with an 

average extinction on prism sections of 42°. The basal sections 

are quite fresh, and show the cleavage parallel to the prism. The 

pinacoids are more developed than the prism faces, and give the 

, appearance of a square with truncated corners, rather than the more 

common octagonal effect. The prism sections vary from stout forms 

to those five or six times as long as broad. In places many small 

pieces are arranged in parallel position and separated by alteration 

products in such a way as to suggest the presence of 'augite phenocrysts, of which these fragments are the remnants. The orthorhombic 

pyroxenes are represented in the darkest-colored rocks by a few basal 

and prism sections, but in the gray varieties it constitutes fully half 

of the pyroxenes present. It is very light colored, not at all pleochroic, is at times partly eaten away, and in other cases occurs as 

intergrowths parallel with the augite. It seems to be a variety poor 

in iron; is optically +, and hence referred to enstatite. In the fresher 

rock specimens the cleavage cracks and borders of the enstatite often 

show the presence of a red-brown fibrous mineral. In the more 

weathered rocks this mineral assumes a prominent r61e. It is here 

'found intergrown with augite and forming fibrous laths, with parallel 

extinction. Its pleochroism is distinct, with a=light brown, c=light 

green. The presence of this mineral in a slide seems to be in proportion to the absence of the orthorhombic pyroxene, and this, together 

with its shape and optical properties, points to bastite and makes 

plausible the supposition that the red-brown mineral is the present 

representative of the original orthorhombic pyroxene. The magnetite 

is present in grains or dust aggregates, and the apatite occurs in 

needles, laths, and rounded sections within the feldspars.

The groundmass consists essentially of long, narrow feldspar laths, 

with ragged outline and' split ends, arranged with trachytic structure 

tending toward the hyalopilitic, and with flow phenomena developed 

in places. No close distinction can be drawn between the groundmass 

feldspars and those which rise slightly above it, as all sizes, up to the
GREGORY.] AUGITE-ANDESITE. 171

very largest present, are represented. Optical measurements on some 

of the freshest pieces in the groundmass proved them also to be labradorite, although orthoclase must also be present, as demanded by the 

analysis. Besides the feldspars, augite grains are scattered abundantly 

throughout the mass, and small areas of brown glass, occasionally with 

bubbles, are also seen. The whole slide is darkened by iron dust, 

both magnetite and limonite or gSthite. The rock is, however, in a 

remarkably fresh state, considering its age and position. Its character 

is unmistakable.

Analysis. The analysis of this rock, made by Dr. W. F. Hillebrand, 

of the United States Geological Survey, is given below (I), and analyses 

of well-known andesites from other localties (II-VII) are given for 

comparison:

Analyses of andesites.

Constituent.

Si02 . ......'...

A12 03 - - .......

Fe2 03 ........

FeO. .........

MgO. ........

CaO. .........

Na2 0.........

K2 0. .........

H2 0 105°.... 

H2 0+105°.... 

Ti02 ..........

Zr02 .........

CrA~ -------

VA ----- :

NiO... .......

MnO. ........

BaO..........

SrO..........

Li2 0 .........

PA .--------

CO...........

Cl. ...........

Fl...... ......

FeS2 .........

Total...

I.

Per cent.

61.40

16. 59

2.13

3.05

2.73

6.17

3.83

1.34

.82 

'.88 

.79

None.

Trace.

.02

Trace.

.13

.02

Trace. ?

.20

None.

?

?

100. 10

II.

Per cent.

61.58

16.96

1.75

2.85

3.67

6.28

3.94

1.28

.24 

1.06 

.49

Trace.

.03

Trarp

Trace.

.22

99.23

ill.

Per cent. 

6\.29

17.68

6.03

.30

2.45

5.61

4.28

1.38

} .96 

.65

100. 63

IV.

Per cent. 

61.04

15.72

5.03

2.15

3.61

5.34'

4.02

2.66

.58

100. 15

V.

Per cent. 

61.45

15.07

4.46

1.18

3.02

5.37

4.00

1.22

1.23

None.

.05

Trace.

(S03 .29)

100. 14

VI.

Per cent. 

61.17

17.74

1.78

3.51

2.76

5.90

3.79

1,71

.83 

.45

None.

.12

.06

.04

Trarp

.14

100. 00

VII.

Per cent. 

63.25

14.89

6.54

None.

.82

.59

4.47

4.78

2.67 

Trace.

.61

.78

Loss . 53

99.93
172 CONTRIBUTIONS TO THE GEOLOGY OF MAINE. [BULL. 165. ;

I. Andesite, Edmunds Hill, Aroostook County, Maine. Analysis by W. F. Hillebrand. vII. Hornblende-andesite, Mount Shasta, California. Analysis by H. N. Stokes, Bull. U. S. Geol. Survey No. 148,1897, p. 190.

III. Hornblende-dacite, Anzeion, JEgina. Analysis by Dr. A. Rohrig.. H. S.Washington, Jour. Geol.,

Vol. Ill, p. 150. . - fc

Yv*. Pyroxene-andesite, Peflon de Pitayo, United States of Colombia. Kuch, Geol. Studien in der ' 

Republik Colombia, Pt. I, Berlin, 1892.

V. Pyroxene-andesite, Agate Creek, Yellowstone National Park. Analysis by Whitfleld, Bull. U. S. 

Geol. Survey No. 148,1897, p. 134.

VI. Hypersthene-andesite, Crater Peak (Lassen Peak region). Analysis by W. F. Hillebrand, Bull.

U. S. Geol. Survey No. 148,1897, p. 197.

VII. ? Andesite, Fox Islands, Maine. Analyses by E. W. Magruder and W. A. Jones, in Johns Hopkins 

University Laboratory. G. 0. Smith, Geology of Fox Islands, Maine. Presented as a thesis, 

Johns Hopkins University, 1896. i

From a study of the above tables it becomes apparent that the j 

Edmunds Hill rock presents no points of distinction from recognized I 

types found elsewhere, and the tables could be greatly enlarged by ^ 

the addition of closely similar analyses. The analysis in Column VII 

requires some notice. The rock is described as a red andesite, with 

"rather basic" feldspars and with calcite and magnetite present. * 

The altered condition of the rock made accurate optical determination 

impossible. In discussing the analysis the writer says: 1 "In its 

mineralogical composition this rock approaches the basaltic type, but, /" 

as the analysis shows, is somewhat too acid. The blivine phenocrysts, , moreover, are not very numerous, and there is reason to regard this ^v 

as simply an olivine-bearing phase of the andesite." The description \ 

is of an andesite, ,but there are discrepancies between the description 

and the analysis. No ferrous iron is present to form magnetite, and 

if the small amount of lime forms calcite basic feldspars could not be 

produced, and even if the whole 0.59 per cent of lime were present as 

andesine or labradorite, the amount is far too small for an andesite. 

According to the generally accepted usage among petrographers, a 

rock with so high a percentage of soda and potash, with little lime 

and magnesia, would be classed as a trachyte, or, more closely, an 

eegirine-trachyte.

HORNBLENDE-ANDESITE. ^

The largest single mass of this rock is Hobart Hill, and the freshest 

and most typical specimens are from this hill and from the west bank 

of the Presque Isle near the northeast foot of the hill, where quarrying 

was at one time attempted. The hand specimen shows a very darkgray, almost black, rock, fine-grained, but with a somewhat porphyritic 

appearance, caused by the occasional feldspar crystals which rise above ' 

the general groundniass and reflect light well from their glassy cleavage 

faces. Some few feldspar laths attain a length of 5 to 6 millimeters. 

The rock breaks out into tabular blocks along the cleavages and weathers to a brownish-gray color. '

Microscopic description. In thin section the microscope reveals , magnetite, apatite, titanite, occasionally a zircon lath, possibly augite, *'

1 Geology of Fox Islands, Maine, p. 34. ' t
GREGORY.] HORNBLENDE-ANDESITE. 173

hornblende, plagioclase, and orthoclase, together with considerable 

secondary calcite. The feldspars range from 2 millimeters in length 

down to minute microlites. The larger feldspars are commonly converted to calcite, which indicates their basic character, but also prevents their accurate determination. Those which could be measured by 

the Michel Levy method proved to be andesine, with formula Abt Ann 

hence more acid than the feldspars of the augite-andesite. They contain 

glass inclusions, are zonally built with an occasional unaltered outer 

border, and are twinned according to the Carlsbad and albite laws, but 

with very irregular intergrowths of the parts.

Hornblende is the only important ferromagnesian mineral present, 

and occurs, as the feldspars, both as large basal sections and long laths, 

often with good crystal outline, and also as shreds in the groundmass. 

The larger pieces are rarely in a good state of preservation, but occur 

with ragged edges and show resorption phenomena. The crystal is 

eaten into, and part of the interior converted into magnetite with a few 

augite grains. Some crystals have been almost entirely replaced by 

calcite and magnetite, and others are represented by a ghostlike outline of magnetite dust. Commonly the hornblende is now changed to 

a green micaceous material, perhaps a variet}7 of chlorite, with parallel 

extinction and a pleochroism, C=white green, rt=brown green. At 

times the former crystal is striped in the direction of the cleavage 

cracks, with alternating bands of green and white. Some of the crystals classed as hornblende are so altered that it is impossible to say 

that they may not be augite.

The groundmass is formed of small, stringy, ragged feldspars, and 

varies in different slides from a trachytic or pilotaxitic type, with 

possibly a little glass, to a type formerly quite glassy and showing 

devitrified areas with incipient micropoikilitic. structure. The feldspar microlites could not be accurately determined, but their average 

extinction indicates a variety as acid as oligoclase andesine, and if strict 

nomenclature were to be considered the rock would be classed as 

a trachyte-andesite.

"SOUTHERN MAPLETON ANDESITES.

These occur in several localities, and are either identical with or 

present only minor variations from the Edmunds Hill and Hobart 

Hill masses. The rock which outcrops in the road 2 miles east of 

Mapleton Village has the most glass}7 groundmass of all the andesites, 

and its devitrified areas have the micropoikilitic structure the best 

developed. Two. outcrops show a type much lighter in color, with 

much secondary and some original quartz, giving the rock a dacitic 

f acies. The other sections examined are of the typical augite-andesite or 

horublende-andesite of this region, and require no detailed description.
174 CONTKIBUTIONS TO THE GEOLOGY OF MAINE. [BULL. 165. {'

CASTLE HILL ANDESITES.

Macroscopic description. The rocks at this place do not have the 

character of lavas which have formed thick flows, but rather suggest x 

the surface of a flow. They .are commonly amygdaloidal, or even A 

slightly brecciated and ashy, and associated with them is an abundance * 

of true volcanic ash with lapilli. The rock exposed at the southeast base 

of the hill is striking in its field appearance. Black, rusty-looking, '} 

spheroidal or elliptical masses of lava, 1 to 2 feet in diameter, first 

attract attention as they lie loosely strewn over the surface. The solid 

ledge itself is composed of these forms, which have their outlines well $ 

displayed by weathering. These sacklike or pillow-shaped masses are ' 

plainly amygdaloidal on the surface, but usually much denser in the 

interior, and are cemented together by a coarse breccia of rough tabu- ^ 

lar, spheroidal, or irregular jagged fragments of glassy material and < 

igneous rock of composition similar to the spheres. In some places, 

noticeably on McDonalds Hill, to the south of Castle Hill proper, this 

structure assumes the f6rm of a conglomerate of small amygdaloidal 

spheres 6 inches and less in diameter, closely cemented together with ^ 

angular pebbles of andesite and other igneous rocks. Similar structures 

have been described from California, 1 Scotland, 2 and elsewhere. As 

noticed by Geikie, some basic lavas, e. g., the basalt at Acicastello in 

Sicily, 3 assume a remarkable spheroidal or pillow-shaped structure on 

flowing into water or a watery silt, "the spheroids being sometimes 

pressed into shapes like piles of sacks." This may be the explanation 

in the present case. Another interpretation is that the structure 

represents the ropy, rolling surface at the front of a lava flow. On a 

fresh surface the rock is dark bluish gray, uniform in texture, or 

with a rare feldspar phenocryst. While this appears to be the most 

typical of the textures, it is usual to find vesicles now filled with calcite \ 

and fragments of volcanic debris large enough to constitute a conspicuous feature in the hand specimen. In weathering, the amygdaloidal 

parts go first and leave the more dense igneous and glassy pebbles : 

exposed as a very rough surface. PL VII will give an idea of the 

external appearance of the rougher forms.

Microscopic description. Sections were cut from the densest mate- --,, 

rial, and also from that with macroscopic inclusions, and when examined with the microscope showed no difference except in size of 

vesicular areas and in method of alteration. Feldspar microlites make *-. 

up the rock, parts of which are developed as areas of vesicular 

lava. The vesicles range from 2 millimeters in diameter to micro- ' 

scopic dots, and are rudely oval in outline. The large ones are merely 

the larger part of a rounded area of vesicular glassy lava, which con1 Ransome, Bull. Dept. Geol. Univ. California, Vol I, p. 106. Fairbanks, Bull. Kept. Geol.. Univ. 

California, Vol. II, p. 40.- ' \ 

*Geikie, Ancient Volcanoes of Great Britain, Vol. I, p. 193. 

8 Johnston-Lavis, South Italian Volcanoes, p. 41,
GREGORY.] DIABASE. 175

tains a few feldspar threads, like the body of the rock. Sometimes, 

instead of one calcite-filled vesicle, the same space will be occupied by 

a group of them, or the concave inner border of the large one may 

indicate its formation from several smaller ones. There are some 

glassy oval areas with vesicles visible only under the highest powers. 

All these variations are, doubtless, caused by the fact that different 

sections of similar vesicular areas are exposed in the preparation of 

the slide. The only feldspar phenocryst seen in the sections is rounded 

in outline, has albite and pericline twinning, and is badly altered to 

calcite. Its extinction angle indicates albite or andesine, and, from the 

fact that phenocrysts are usually more basic than the components of 

the groundmass, it is referred to andesine. No ferromagnesian mineral 

is present, but the numerous patches of chlorite and the occurrence of 

augite in similar rock in the immediate neighborhood point to the 

former presence of pyroxene. Besides chlorite, there are present, as 

secondary products, calcite, a few epidote grains, and abundant iron 

ore. One slide is sprinkled full of stringy black iron ore in long 

threads or lines of partly connected dots, which are arranged to form 

barbed arrows or a network of fibers that cross at angles of 60° and 

90°, thus imitating the sagenite structure of rutile.

The groundmass is of long, stringy, narrow, frayed-out microlites 

of feldspar with trachytic structure. Measurements of many laths 

gave practically a parallel extinction, thus indicating oligoclase. 

Expansion structure is developed where the vesicular areas are large 

enough to affect the orientation of the minute laths constituting the 

main body of the rock.

ANDESITE ASH BEDS.

Beds of volcanic ash of an andesite character are represented in 

the region covered by this report. They are particularly abundant 

about Castle Hill, and are discussed in the chapter on clastic-rocks.

DIABASE. 

AROOSTOOK FALLS DIABASE.

The diabase from Aroostook Falls is a dark-gray rock with characteristic lamprophyric appearance, quite dense and uniform in texture 

to the unaided eye, with the exception of numerous grains of pyrite 

and a few greasy-looking feldspars which give it a slight porphyritic 

facies. It weathers to an iron-rust color, but the face of the dike 

next the limestones often shows a jet-black slickensided surface, as if 

some carbonaceous matter had been produced by the intrusion.

Under the microscope the minerals found in this section are apatite, 

iron ore (mostly pyrite, which is abundant), pyroxene, and plagioclase, 

with chlorite as an alteration product. The larger feldspars (1 millimeter in length) form crystals whose basic character is suggested by 

their alteration to calcite, but which a,re t99 ffiUQh decomposed to
176 CONTKIBUTIONS TO THE GEOLOGY OF MAINE. [BULL. 165.

measure. No other mineral rises above the groundmass, and the 

whole section otherwise shows a uniform aggregate of feldspar laths, 

which are stout rectangular to long irregular in shape, and among 

them are embedded more or less rounded grains of quite fresh, colorless pyroxene. The structure of the groundmass is therefore not the 

ordinary ophitic type common to diabases, but corresponds to the 

granulitic type of Judd. l The feldspar microlites show twinning, but 

could not be satisfactorily measured, and their basic character is calculated from the analysis. A quantity of the rock powder was tested for 

nepheline, but it yielded no gelatinous,silica.

Analysis. The following analysis (I) of a specimen from the largest 

dike was made by Dr. W. F. Hillebrand, of the United States Geological Survey.

Analyses of diabase.

Constituent.

Si(V .................

A1A- .............

FP r>

FeO...... ............

MgO .................

CaO. ...... ...........

Na^O...... ...........

K20. .................

H2 0-105. ............

H2 0+105. ............

TiO,. .................

Zr02 .................

0,0,. ........ .....

Va08 -------- - -----

NiO. .................

MnO.... .............

BaO. .................

SrO. .................

*Li2 0 .................

P O

C02 . ................

Cl.... .................

FL... ...............

FeS2 . ................

Total..........

I.

Per cad. 

49. 64

15.07

1.66

'8.82

5.43

7.23

. 4.19

.89

.45

2.81

2.32

None.

Trace.

.04

.25

.02

.05

Trace.

.29

.32

?

?

f (.438)

I .79

100. 27

II.

Per cent. 

49.27

15.87

1.93

10.17

5.90

7.46

3.45

.74

^ 3. 92

.35

1.12

100.18

Hi.

Per cent. 

52.37

. 15. 06

2.34

9.82

5.38

7.33

4.04

.92.

2.24

.21

.32

«

100. 03

IV.

Per cent. 

51.80

14.21

3.55

 8. 26

-7.63

10.68

2.15

.39

.63

.42

.14

99.86

V.

Per cent. 

49.25

16.97

| 15.21

3.00

7.17

4.91

2.01

.30

1.41

Trace.

.76

100. 99

i Judd, Gabbros, etc., in gcgtland. and Ireland.; Qua.rt, Jour, Geol. Soc., Vol, XIJI,:
GREGORY.] MARS HILL DIABASE. 177

I. Diabase from Aroostook Falls, New Brunswick. Analysis by W. F. Hillebrand, United Slates 

Geological Survey.

II. Diabase or chloritic dolerite from Lake Saltonstall, Connecticut. Analysis by G. W. Hawes, Trap 

rocks of the Connecticut Valley: Am. Jour. Sci., 3d series, Vol. IX, 1875, p. 190.

III. Diabase from Reeds Gap quarry, Middlefleld, Connecticut. Analysis by Dr. J. H. Pratt, of Shei 

field Scientific School. (Not published.)

IV. Diabase (dolerite) from West Rock, New Haven, Connecticut. Analysis by G. W. Hawes, Trap

rocks of the Connecticut Valley: Am. Jour. Sci., 3d series, Vol. IX, 1875, p. 186. 

V. Essexite (olivinegabbro-diabase). Digntes. Kirchspiel Gran. Norway. Analysis by Schmelck. 

Brogger, Quart Jour. Geol. Soc. London, Vol. L, 1894, p. 19.

Dismission ofcmatysis. The above analyses show that in composition 

the Maine rock is very near those diabases of the Lower Connecticut 

Valley which have been mapped as extrusives, while it is somewhat 

lower in lime and higher in soda than the specimen from West Rock 

(IV), which is typical for the intrusive sheets of the region. Analysis 

V is given to show the relation to the essexites arid rocks of similar 

character. Comparison with many analyses other than those given in 

the table suggests the idea that the Aroostook Falls dike is a transition 

between a diabase of normal type and rocks of the theralite-essexite 

magma.

MARS HILL DIABASE.

The two dikes found at this locality differ widely in appearance and 

type of structure. The easternmost dike closely resembles the rock 

described from Aroostook Falls and is considered as normal for this 

region. The other dike is exceedingly basic in composition and is 

microscopically characterized by the presence of a glassy base. '

NORMAL TYPE.

The normal type of diabasic dikes forms the easternmost occurrence 

at Mars Hill. Owing to the presence of pyrite and a few feldspars 

larger than the microlites of the groundmass, the rock appears slightly 

porphyritic to the unaided eye, and on much weathered surfaces it 

presents a bleached, slaggy appearance. Securely cemented within 

the diabase are fragments of a blood-red jasper, which vary in size 

from mere specks to blocks several feet square. These jasper inclusions 

are never rounded, but present straight, clear-cut edges against the 

diabase and show clearly the marks of stratification. It is also 

noticeable that the center of the jasper blocks is a dull brownish-red, 

amorphous-looking, baked slate, while at the contact with the igneous 

rock it becomes blood red and has a shiny crystalline appearance. 

These jasperlike fragments are considered siliceous iron-bear ing slates, 

which have been broken off and included by the dike in its ascent, and 

which in consequence have been metamorphosed.

Microscopic description. Under the microscope feldspar and augite

appear as the components. The few small phenocrystic feldspars are

too badly decomposed to be determined, but if more basic than those

constituting the groundmass, as is to be supposed, they are probably

Bull. 165 12
178 CONTEIBUTIONS TO THE GEOLOGY OF MAINE. [BULL. 165.

andesine. The feldspars of the groundmass are long, narrow, poorly 

bounded individuals, nearly all striated, with an extinction nearly parallel, and hence oligoclase. Colorless augite is scattered thickly 

through the slide, commonly as grains, but also as prisms and basal 

sections, and these occasionally extinguish in common, thus suggesting 

the ophitic structure. In places the feldspar microlites have some 

tendency to a spherulitic structure. Chlorite and iron are abundant 

in specks and patches, and calcite and quartz, together or separately, 

occupjr the cracks in the rock. '

.The included jaspers are too dense to show structure and are often 

partly surrounded by material composed of fragments of arkose, 

feldspar, and quartz grains, set in a fine groundmass of similar material. 

This would indicate that the jasper was already part of a conglomerate when fragments were removed by the igneous intrusion. It is 

possible, however, that the presence of the arkose is due to secondary 

processes.

GLASSY TYPE.

The glassy type appears in the-hand specimen as an exceedingly 

dense, blue-black rock with a dull luster and without the ordinary 

characteristics of vitreous material. Occasionally a small dot of red 

jasper is visible, but no other structures or minerals can be seen. The 

rock is very tough, and where struck with a hammer is reduced to a 

powder of a lavender-gray color. Slickensides along the intersecting 

cleavages show movement since the mass has been in place.

A thin section examined under the microscope revealed no minerals 

present except a few rounded augite grains and some serpentine filling 

cracks, but it showed a groundmass composed entirely of very minute, 

feathery fragments of some material which was not resolvable under the 

highest powers. These feathery structures are so arranged about, 

centers as to form round or elliptical spherulitic aggregates. Direct 

evidence as to the nature of this groundmass is wanting, but that it is 

glassy and formed by sudden cooling seems evident. Whether the 

spherulitic structure is secondary or primary, or, if secondary, what 

its former nature was, is doubtful. The suggestion is made that it 

may have been formerly a peiiite reduced to its present condition by 

devitrification. A few glassy spheres remaining in one place bear out 

this supposition. The whole slide is densely sprinkled with chlorite 

and iron dust,- thus bearing testimony to the basic character which the 

analysis brings out so clearly.

Analysis. The following analysis (I) by Dr. W. F. Hillebrand, of the 

United States Geological Survey, was made from the freshest material 

obtained. Analysis II is inserted for comparison.
GREGOUY.] TESCHENITES. 

Analyses of basic diabases.

179

Constituent.

ftiO

A1A ----------

FeA ----------

FeO.... ........

MgO ...........

CaO...... ......

Na.,0..., .......

J^O. ...........

H20-105°......

HjO+1050 ......

TiO, ...........

Zr02 ...........

OA-----------

I.

Per cent. 

42. 25 -

16.87

5.24

19.72

6.91

3.33

3.96

.77

.43

K CO

2.93

None.

.03

II.

Per cent. 

42.5

12.7

11.40

6.80

13.10

} 5.08

| 6.50

Constituent.

VA ...........

NiO.... ........

MnO ...........

BaO............

SrO ............

Li 20 ...........

p r>

CO,.... ........

Cl. .............

Fl..............

FeS2 ...........

Total .......

I.

Per cent. 

.07

.01 .

.40

Trace?

None.

Trace.

.34

None.

?

?

(Trace S.)

Trace.

99.84

II.

Per cent.

1.30

1.30

100. 68

I. Glassy diabase, Mars Hill, Maine. Analysis by Dr. W. S. Hillcbrand, United States Geological 

Survey.

II. Limburgite (magma basalt), Hohc voii Skalka, Bohemia. Analysis byBoricky,Math.-naturwiss. 

Class zu Prag, Jan. 12, 1872; cit. Jahrb. Min. 1872, p. 959.

Discussion of analysis. The above analysis indicates a basaltic 

magma between the gabbro and the peridotite groups. In the absence 

of crystallized minerals only theoretical compositions can be calculated, but it is very probable that a magma so rich in magnesia and 

ferrous iron would form, on crystallization, much olivine, and, with the 

abundant alumina, augite also. These minerals would require all the 

lime present, and hence feldspars containing the anorthite molecule 

could not be formed, but rather nepheline, or, if water were present, 

analcite. In such a case the basic lamprophyric dike would be classed 

as nepheline-basalt or analcite-basalt.

TESGHENITES. 

FIELD APPEARANCE.

< The field appearance of this rock is characteristic, and a person with 

but slight acquaintance with igneous rocks would not confuse it with 

the other dikes or with the lavas of this region. But in spite of its 

general characteristic appearance, its variation within certain limits is 

remarkable, as has been noticed in rocks of this class from other localities. So great is this variation that at first sight the impression is 

conveyed that there are here a number of dikes of somewhat different 

composition and structure which have interpenetrated one another or 

come up as parallel intrusions. They are all parts of one dike, how-
180 CONTRIBUTIONS TO THE GEOLOGY OF MAINE. . [sou,. 166.

ever, and no line of demarcation is possible between the different 

phases. The teschenites are readily decomposed by weathering, breaking down in place to a fine, brown sand, which accounts for the absence 

of sharp cliff ledges at the outcrops and makes it difficult to secure 

unaltered material. Even the specimens obtained by blasting, which 

appeared beautifully fresh in the field, were "found by examination of 

thin secti'ons to contain many altered minerals.

In the following description the varieties obtained will, for the sake 

of simplicity, be grouped under three heads: the coarse "crystalline 

type, the granular type, and the contact fades. For a map of this 

district see page 116.

COARSE CRYSTALLINE TYPE.

This constitutes nearly all the great dike on lot 100 and the outcrop 

at the northeast corner of lot 107.

Macroscopic description. Typical hand specimens show a rock made 

of a mixture of white or pink and lustrous black materials in about 

equal quantities, but with a tendency toward aggregation of like parts 

which makes dark and light areas. The light parts are composed of 

white or pink feldspars, in the midst of which are good-sized areas of 

milk-white analcite. The dark parts are composed ^of black augite 

mingled with grains of magnetite. Masses of oily green chloritic 

material are also macroscopically apparent. The crystals will average 5 

to 6 millimeters in largest diameter. From this type, in which the dark 

and light components appear equally represented, there is a variation 

on the one hand to a black crystalline aggregate of augite and iron, 

and on the other to a tangled mass of feldspar laths, filling the interspaces and containing black minerals without definite outlines. One 

feldspathic variety is unique in some particulars. It is composed

largely of good-sized, perfectly formed pink feldspar, with shining 

cleavage faces and with the ferromagnesian minerals wanting or reduced 

to inconspicuous grains. The rock is much weathered and shows 

numerous irregular cavities, from which some mineral has been removed 

and which are now lined with black dust or rarely filled with calcite. 

Such cavities are found also in weathered parts of the other varieties. 

Microscopic description. Several slides of this coarse type of the 

teschenites were prepared, none of which showed all the minerals in 

good condition, but the character of each was very well made out by a 

comparative study. The minerals present in the order of their formation are: Black iron ore, with a few grains of pyrite; apatite, biotite, 

feldspar, augite, and analcite. This order, however, is not strictly 

observed, and the appearance is more as if several minerals had been 

crystallizing simultaneously. The iron ore is largely magnetite and is 

very abundant in. the section as partly formed polygons or irregular
GREGORY.] , TESCHENITES.

grains, with bays and internal cavities often filled with biotite or its 

alteration product. The aggregation of biotite and magnetite is 

noticeable in all the sections. The large amount of titanium given 

in the analysis suggests ilmenite, but the iron grains are readily picked 

up by the magnet. Apatite is thickly distributed through the rock 

in long broken needles and well-formed crystals which penetrate the 

feldspars in particular very deeply.

The biotite is a pale yellow-brown variety, pleochroic, with distinct 

cleavage and regular or ragged border, and is found included by or 

grouped with the magnetite, or more rarely scattered through the 

section. It is found in various states of alteration, and stages can be 

traced from the yellow unaltered biotite to a deep-red, fibrous or compact serpentinous mineral. This alteration product appears somewhat 

like the iddingsite found in the California teschenite 1 and quite commonly in basalts, but there is here no olivine represented by crystal 

outline or characteristic parting, nor lines of alteration, as is the case 

in slides where the red mineral occurs as the undoubted secondary 

mineral after olivine, and therefore the presence of olivine is not 

assumed. :

Augite is the most prominent rock constituent by reason of its 

development into large, well-formed crystals and its beautiful violetbrown color and faint pleochroism. The prism sections, which are 

about twice as long as broad, sometimes attain a length of half an inch 

and may have perfect crystal boundaries or broken, irregular edges. 

Basal sections are generally almost square by slight development of 

prism faces, but show also rounded and rectangular outlines. In some 

specimens the violet augite has a light-green border of some segirine 

type of pyroxene, which is also occasionally present apart from the 

augite. The augites have altered along the cleavages to the same 

reddish mineral found replacing the biotite, and occasionally the crystal 

is entirely replaced by a green chloritic mineral or by calcite, or may 

be bordered by a zone of serpentine, often in radial bunches.

The feldspars occur typically in long, broad laths or narrow, rodlike bodies. They are nearly all striated and occasionally have Carlsbad twinning. The largest crystals are in the pink variety, and here, 

as in all types, alteration products prevent accurate determination in 

the majority of cases. However, sections are present in the slide 

which have the albite and Carlsbad twins developed and are fresh and 

bright in appearance. One such section was cut in the zone suited for 

optical determination by the Michel LeVy method, and gave the following measurements: Albite extinction, 13°; Carlsbad, 4°; the difference is 8°, and by reference to the table is found to correspond to the

i Bull. Geol. Dept. Univ. California, Vol. 1 aud Vol. II.
182 CONTEIBUTIONS TO THE GEOLOGY OF MAINE. [BULL. 165.

composition Ab5An3 , and is therefore andesine (see fig. 11). The most 

common alteration is a clouding by means of myriads of minute specks 

of pure white analcite, which is distributed without order along cracks 

or in the center, or as a zone surrounding the crystal. The feldspar 

also shows chlorite or serpentine along the cracks, or may be striped 

by alternate bands of chlorite and calcite. . A. whitish isotropic mineral, with low refraction and birefringence 

abundantly present in the rock, suggested leucite, sodalite, and analcite. 

In order to determine which of these minerals was present, a portion 

of the rock powder was treated with dilute nitric acid and then filtered, 

and the filtrate yielded gelatinous silica so easily and abundantly that 

the mineral could not be leucite. A test of a portion of the original 

filtrate showed no chlorine, which the presence of sodalite would 

demand. Moreover, the rock yields water abundantly below red

FIG. 11. Optical measurements of a plagioclase crystal.

heat in the closed tube. Analcite is the only rock-making mineral 

which corresponds in composition and optical behavior to the one 

under discussion.

The analcite of the teschenite is either pure white or clouded by dust 

particles, and the slight birefringence is accordingly variable. It occurs 

abundantly in the typical slides, filling the polygonal areas between the 

interlacing feldspars, or filling cavities partly bounded by crystal faces, 

or as the secondary product described above. No alteration to secondary minerals, as has been recorded by Fairbanks, was observed. The 

disputed question of the origin of the analcite in rocks of this class 

finds no additional evidence here, but the writer believes, with Rosenbusch 1 and Fairbanks, 2 that it is secondary probably after nepheline, 

and not primary, nor secondary after feldspar, as maintained by Rohrback. 3

1 Kosenbusch, Mikrosk. Phys. der mass. Gesteine, p. 253. 

2 Fairbanks, Bull. Geol.Dept.TJiiiv. California, Vol. I, p. 284; Vol. II,p. 27.

3 Rohrbach, Ueber die. Eruptivegesteine im Gebiete der Schlesich-Mahrischen Kreideformation: 

Tschermaks Mittheilungen, 1886, Vol. VI, p. 31.
GREGORY.] ANALYSES OF TESCHENITES. 183

The structure is, in a way, the ophitic of the diabases, in that the feldspars have crystallized before the augites, but the arrangement is not 

one where augite grains with common orientation fill the interspaces 

between the feldspar laths, but single large augite crystals are cut 

into two or more separate parts by rodlike feldspars which penetrate 

them at different angles, and the effect between crossed uicols is somewhat suggestive of poikilitic structure. An average of all the coarsely 

crystalline specimens would give a structure between the granitoid 

and that of ordinary diabases. It is indeed quite probable that all of 

the essential components were in process of formation at one time.

Analysis. The following analysis (I) by Dr. W. F. Hillebrand, of the 

United States Geological Survey, was made from the freshest specimen of the coarse crystalline variety from the dike cut through by the 

wagon road:

Analyses of teschenites and related roch.

Constituent.

Si02 .---.-

A1A-----

FeA-----

FeO ......

MgO......

CaO ......

Na^O .....

K20......

1-1,0 105° 

H,0+105°

TiO

Zr02 ......

Cr203 .....

VA------

NiO ......

MnO .....

BaO......

SrO. ......

Li20 ......

PA ------

CO,. ......

Cl.. ......

Fl........

FeS2 ......

Total .

I.

Per cent. 

46.77

14.91

. 7.80

4.90

2.94

6.30

4.97

2.37

.92 

4.28 

2.31

None.

.02

.29

.04

.03

.98

Trar'p?

?

Trace.

((. 036 S)

I .07

99.90

II.

Per cent. 

44.65

13.87

6.06

2.94

5.15

9.57

5.67

4.49

.96 

2.10 

.95

17

.76

.37

Trace.

1.50

.11

Trace.

/Q/-\ /> ! \

(fc>U3 . bl)

99.92

III.

Per cent. 

44.31

17.20

4.64

.3.73

6.57

10. 40

4.45

3.64

.77 

3.30 

Undet.

.10

99.11

IV.

Per cent. 

47.67

18.22

3.65

3.85

6.35

8.03

4.93

3.82

.38 

2.97 

Undet.

.28

100. 15

V.

Per cent. 

48.18

11.80

9.79

5.90

6.05

7.50

3.46

1.57

| 3. 20

.49

.71

Trace.

98.65

VI.

Per cent. 

49.61

19.18

2.12

5.01

4.94

10.05

5.62

1.04

3.55

-

<»

.27

101. 39

VII.

Per cent. 

46. 48

16.16

6. 17'

6.09

4.02

7.35

5.85

3.08

4.27 

.99

.45

100. 91

VIII.

Per cent. 

46. 99

17. 94

2.56

7.56

3.22

7>. 85

6.35

2.62

.65 

2.92

None

.94

99. 60
184 CONTRIBUTIONS TO THE GEOLOGY OF MAINE. [BOLL. 165.-

T. Teschenite from Mapleton Township, Aroostook County, Maine. Analysis by Dr. W. F. Hillebrand, United States Geological Survey.

II. Theralite from Gordons Butte, Crazy Mountains, Montana. Analysis by E. A. Schneider, 

Bull. U. S. Geol. Survey No. 148,1897, p. 146.

III. Theralite from Gordons Butte. Another sample of II. Analysis by Schneider.

IV. Theralite, north of Alabaugh Creek, Crazy Mountains, Montana. Analysis by E. A. Schneider 

Bull. U. S. Geol. Survey No. 148, 1897, p. 146. ' 

V. Teschenite from. Boguschowitz, Silesia. Analysis by Tscherinak, Teschermaks Mln. mid Petrog.

Mitth., Vol. VI, 1885-86, p. 42.

" VI. Augite-teschenite, Point Sal, California. Analysis by H. W. Fairbanks. Fairbanks, Geology 

of Point Sal: Bull. Dept. Geol. Univ. California, Vol. II, 1896, No. 1, p. 31.

VII. Monchiquite, Brazil. Analysis by Hunter, Tschermaks Min. und Petrog. Mitth., Vol. XI, 

1890, p. 464.

VIII. Essexite from Salem Neck", Massachusetts. Anal ysis by H. S.Washington. Washington, Petrographical Province of Essex County: Jour. Geol., Vol. VII, 1899, No. 1, p. 57.

Discussion of analysis. An inspection of the analysis (I) shows 

that therp is not enough ferric oxide to convert the titanium dioxide 

and ferrous oxide into iron ore, and it is probable that part of the 

titanium dioxide is present in the augite, as would be expected from 

its violet color. It is evident that the soda and potash could not be 

converted into feldspar without forming a variety much richer in soda 

than the analysis shows. Perhaps soda orthoclase is present, but it 

seems quite certain that there is also some sodium aluminate coinpound besides feldspar in the rock. Furthermore, the amount of 

silica present is not sufficient to convert the potash, soda, and lirne 

into feldspars, and some feldspathoid would be formed; this was most 

likely nepheline. Some of the analcite present is certainly secondary, 

an^ it is quite probable that it all is so.

Comparison of the analyses in the table given above will show the 

close relationship between the Maine rock and the typical theralites, 

and it is very probable that the former was a theralite in its original 

condition. ,

In regard to the essexite (VIII), Dr. Washington says that " nepheline is fairly abundant, generally interstitial, but occasionally in wellshaped crystals." 1 This fact, together with the closely similar chemical composition, goes to show how closely related are the members of 

the theralite-essexite-teschenite series.

GRANULAR TYPE. "

Macroscopic description. The same minerals are found in this tpye 

as in the coarsely crystalline, but their form,, relative abundance, and 

method of arrangement are different. In the hand specimen no distinct 

crystals are seen and the rock appears more as a fine, even-grained, 

brown sandstone. The areas where this type occur are very different 

in appearance from the other parts of the large dike, but are not separated by any distinct boundaries. The specimen from lot 100 has the 

character of a fine-grained lamprophyre.

i Jour. Geol., 1899, Vol. VII, No. 1, p. 54.
GREGORY.] TESCHENITES. 185

Microscopic description. The microscope shows the feldspars shorter 

and narrower than those in the main dike mass, the micas much more 

abundant, and the augite, now largely represented by chlorite, in 

grains or small granular crystal sections, and not in long prism sections. Their color and pleochroism, too, are absent. The apatite is in 

exceedingly fine needles, and calcite is more common as an alteration 

product. The iron is still abundant, but in smaller, irregular grains 

and crystals.

The granular representative from lot 106 is in the nature of a transition from the rock just mentioned to the crystalline type. The minerals revealed by the microscope are as before iron, apatite, mica, 

feldspar, and analcite. Iron is in small, black and brown, irregular or 

polyhedral grains. Biotite is the most abundant dark mineral and 

OCCUl'8 in good-sized sections,i which often shoAV alteration to the yellow-red mineral common in all these rocks. The augite is almost colorless and occurs as small ciystal sections and grains, always of smaller 

size than the mica, and never becoming a markedly noticeable component. The feldspars are oligoclase in laths shorter and narrower than 

the other types, and the analcite is not a prominent constituent. In 

structure this granular variety resembles the groundmass in finegrained panidiomorphic kersantite.

CONTACT FACIES.

Macroscopic description. A few feet from the sedimentaries on the 

south the teschenite of the dike along the west side of lot 99 assumes 

a particular variation due to contact with the slates. The rock here 

assumes a deep-black color, is exceedingly dense and tough, and is distinctly porphyritic by the presence of pink feldspar laths and an occasional augite crystal in the cryptocrystalline groundmass. At the 

contact the hand specimen shows numerous angular fragments of slates 

embedded in the igneous rock and tongues of the teschenite, reaching 

into the hardened slates, but no smooth contact walls were observed. 

Weathered surfaces show cavities left by decaying feldspar phenocrysts, 

which give the rock a porous aspect.

Microscopic description. Microscopic examination reveals a black 

cryptocrystalline groundmass in which are embedded phenocrysts of 

feldspar and augite. The augite is represented only by its outline, 

which, however, is perfect, and with its bright filling of calcite stands 

in marked contrast to the black groundmass. The feldspars also have 

clear crystal outlines, rarely with notched ends, and have nearly all 

gone over to calcite.

The groundmass is composed of a black dust with particles arranged 

in blotches or rude spherulitic form so as to leave yellow areas between 

theni. Under the highest powers the radial structure is more pro-
186 CONTEIBUTIONS TO THE GEOLOGY OF MAINE.

nounced in the black areas. Between crossed nicols the black is isotropic, and the yellow spots are but faintly birefringent. A great 

quantity of iron dust seems to be present, and probably some glass also.

The slates included in the rock are hard, gray fragments composed 

of minute quartz and feldspar grains, together with secondary chlorite 

and calcite.

The specimen from Castle Hill is very badly decomposed, but the 

abundance of apatite, the presence of the violet augite, and the general 

structure of the rock all indicate similarity to the typical teschenite of 

Mapleton.
CHAPTER V.

PETROLOGY.

The igneous rocks of the Aroostook area are widely separated in 

geographic position, and yet the distinctive volcanic types are found 

in a rather limited district.

The granite areas are small and about 40 miles apart. The diabase 

dikes are not numerous, and typically are found cutting the folded and 

slated Aroostook limestone. The lavas rhyolite, trachyte, and andesite are contained within an area about 12 miles by 6 miles, and with 

them are found the most typical tuff s and volcanic conglomerates. As 

the land exists to-day the Castle Hill-Mapleton area appears as a distinct center of volcanic activity within which intrusions and extrusions have formed at the same or different times. The presence of 

lavas of different character is not inconsistent with the idea of a limited center of activity, and all the field relations indicate a few small 

vents or fissures rather than powerful volcanoes which have ejected 

immense quantities of lava.

No petrologic work has been done previously anywhere near this 

region, but from the field descriptions of geologists limited areas of 

similar rocks are supposed to exist in northwest New Brunswick, in 

eastern Quebec, and along the lakes in central Maine. Specimens collected at Temiscouata Lake by Prof. H. S. Williams are andesitic tuffs 

and breccias. Along the coast line the rocks have been studied at St. 

John, New Brunswick, and found to be granite-diorites, gabbros, 

felsite, porphyries, diabases, and porphyrites. 1 Farther west along 

the Maine coast aporhyolites, andesites, and other volcanics have been 

described. 2 In the province of Quebec, on the west of Maine, large 

areas of anorthosite exist, some of which have been studied 3 by the 

Canadian survey. It is to be hoped that more of these isolated areas 

within the sedimentary slates will be described and some data secured 

which will permit a discussion of their general petrology in detail.

The anatyses of all the rocks from this region are here given in one 

table, for ready reference.

1 W. D. Matthew, Trans. New York Acad. Sci., Vol. XIII, 1894, p. 185, and Vol. XIV, pp. 187-217. 

- Bayley, Bull. Geol. Soc. America, Vol. VI, 1894, p. 474,. Smith, Geology of the Fox Islands, Maine. 

3 See the writings of P. D. Adams.

187 .
188 CONTKIBUTIO.NS TO THE GEOLOGY OF MAINE, [BULL. 165.

Analyses of rocks from northeast Maine,. 

[Analyst, Dr. W. E. Hillebrand.]

Constituent.

Si02 .......

A12 03 ......

Fe203 ......

FeO .......

MgO. .----.

CaO.......

Na2 0 ......

KjO. ......

H2 0-105° . 

H.,0+1050 . 

Ti02 .......

Zr02 .......

O,0S ------

VA- -

NiO .......

MnO ......

BaO.......

SrO........

LiaO .......'

PA-------

C02 . .......

01.........

Fl. ........

FeS2 .......

Total .

i.

Per ct. 

75.98

12.34

.85

.93

.15

.13

4.02

4.44

.24 

.64 

.17

.03

?

.?

Trace?

.07

Trace?

Trace?

.03

?

?

100. 02

II.

Per ct.

72.77

12. 15

.44

3.06

.22

.07

3.38

4.67

.17 

.55 

.20

.04

?

.16

.03

None. ?'

2.06

?

?

K.067S)

I .12

100. 09

ill.

Per ct. 

61.40

16.59

2.13

3.05

2.73

6.17

3.83

1.34

.82 

.88 

.79

Trace.

.02

.13

.02

.20

?

° ?

100. 10

IV.

Per ct. 

49.64

15.07

1.66

x 8.82

5.43

7.23

4.19

.89

.45 

2.81 

2.32

Trace.

.04

.25

.02

.05

.29

-.32

? 

?

r(-43S)

I .79

100. 27

V.

Per ct. 

42.25

16.87

5.24

10. 72

6.91

3.33

3.96

.77

.43 

5.58 

2.93

.03

.07

.01

.40

Trace?

None.

.34

?

?

(Trace S)

Trace.

99.84

VI.

Per ct. 

46.77

14.91

7.80

4.90

2.94

6.30

4.97

2.37

.92 

4.28 

2.31

None.

None.

.02

Trace.

.29

.04

.03

.98

Trace?

?

TVflpp

(. 036 S)

.07

99.90

VII.

Per ct. 

31. 42

11.57

2.37

7.48

5.32

16.71

2.26

.74

.76 

4.17 

 2.30

None.

" Trace.

.06

Trace.

.38

.64

None.

.46

' 13. 13

V

?

(.0868)

.16

99.93

fwii.

Per ct. 

54. 23

7.38

.54

1.37

3.29

14.-65

1.65

1.74

.25 

1.22 

.28

?

?

?

None.

N. est.

None.

None.

Trace.

.07

13. 48

?

?

?

100. 06

I. Rhyolite, Haystack Mountain.

II. Quartz-trachyte, Qnoggy Joe Hill. ' .

III. Andesite, Edmunds Hill.

IV. Diabase, Aroostook Falls.

V. Diabase, Mars Hill.

VI. Teschenite, near Mapleton Village.

VII. Volcanic tuff, southeast base of Castle Hill.

VIII. Calciferous sandstone, New Sweden Township.

These analyses show that the igneous rocks of the district are of an ; 

alkaline type. The andesite (III) is of the ordinaiy plagioclastic char- ' 

acter, but the rocks more acid and those less acid than the andesites 

show an alkaline tendency. This is the most evident point in their 

regional affinity.
CONTRIBUTIONS TO THE GEOLOGY OF MAINE.

Part III.-LIST OF LOCALITIES OP PALEOZOIC, IGNEOUS, AND OTHEK

CRYSTALLINE ROCKS EXAMINED DURING THE

SEASONS OF 1897 AND 1898

H. S. WILLIAMS

189

.CONTENTS OF PART III.

	Page. 

Aroostook County, Maine................................................. 193

Houlton ............................................................. 193

Mars Hill, Blaine..................................................... 193

Monticello ........................................................... 194

Bridgewater.......................................................... 194

Easton......... ....................................................... 194

Fort Fair-field.. ...................................................... 194

New Limerick........................................................ 194

Presque Isle.......................................................... 195

Caribou............................................................... 195

Oakfield............................................................. 195

Smyrna..................................,..............'............. 19,6

Weeksboro........................................................... 196

Township9, Range 3.................................................. 196

Chapman............................................................ 196

Mapleton ............................................:............... 196

Washburn ........................................................... 197

Woodland ........................................................... 198

New Sweden......................................................... 198

St. Croix..................................:.......................... 199

Griswold............................................................. 199

Hedgehog Mountain = Township 11, Range 4 .......................... 199

Castle Hill........................................................... 199

Wade................................................................ 201

Perham.............................................................. 201

Madawaska Lake..................................................... 201

Township 9, Range 5.................................................. 201

Masardis--.........-........---......-.-.-.-.-.-.-..---.............. 202

Ashland .............................................................. 202

Sheridan............................................................. 202

Garfield ............................................................. 202

New Brunswick.......................................................... 203

191

. CONTRIBUTIONS TO THE GEOLOGY OF MAINE.

PART III, LIST OF LOCALITIES AT WHICH OUTCROPS WERE EXAMINED 

DURING THE SEASONS OF 1897 AND 1898,1

By HENRY S. WILLIAMS.

AROOSTOOK COUNTY, MAINE.

[Arranged in order of townships.]

1295. HOULTON (TOWNSHIP 6, RANGE 1).

A. An exposure on east side of railroad, south of station near the bridge.

B. Cut on Bangor and Aroostook Railroad, half a mile north of Houlton Station,

at milepost 128 from Oldtown. 

C. Cut on Canadian Pacific Railroad, three-fourths mile southeast of station at

Houlton. 

D. On Merrithew's farm, near Greenville Station, on Canadian Pacific Railroad.

(This farm may be in New Brunswick.)

E. Falls on South Branch Meduxnekeag River, at Carys Mills. 

F. Cut on Bangor and Aroostook Railroad, 1,200 feet north of milepost 128 from

Oldtown, three-fourths mile north of Houlton Station. 

G. Cut on Bangor and Aroostook Railroad, 1,500 feet north of milepost 128 from

Oldtown, three-fourths mile north of Houlton Station. 

H. Cut on Bangor and Aroostook Railroad, at milepost 129 from Oldtown, 1 £

miles north of Houlton Station. 

K. In field just west of Canadian Pacific Railroad station, Houlton.

1296. MARS HILL, BLAINE (TOWNSHIP 10, RANGE 1).

A. About one-fourth mile southwest of station, at Mars Hill, in a field east of

Joe Lincoln's house.

B. In village of Mars Hill, east side of river, at dam, corner of road. 

C. Cut on Bangor and Aroostook Railroad, one-third mile north of station at

Mars Hill.

D. In field, about one-fourth mile west of Joe Lincoln's house (1296 A). 

E. East side of starch factory, 1 mile northeast of Mars Hill post-office. 

F. In field, northwest corner of Mars Hill Mountain, east of road, by a bridge. 

G. On George York's place, northeast corner of Mars Hill Mountain, hillside

south side of brook, in woods. 

H. East side of north end of Mars Hill, just above (on northeast side) brook on

George York's place, in woods, three-fourths mile south of house. 

J. Cut on Bangor and Aroostook Railroad, 750 feet north of milepost 156 from

Oldtown, 1.86 miles south of station at Mars Hill.

1 The localities are arranged by townships, and the numbers are station numbers of the United 

States Geological Survey catalogue and are attached for identification to the specimens, which will 

ultimately be deposited in the National Museum. References to these station numbers are made in 

both the paleontologic and the petrographic notes of this report, and in cases not actually recorded in 

this report are preserved in field and laboratory notebooks for future reference.

Bull. 165 13 . 193
194 CONTRIBUTIONS TO THE GEOLOGY OF MAINE. [BULL. 165.

1296. MARS HILL, BLAINE (TOWNSHIP 10, RANGE 1) Continued.

K. South end-of Mars Hill, west side, section running from bottom (McPherson's house) to highest summit.

L. Cut on Bangor and Aroostopk Eailroad, Robinson Station. 

M. Cut on Bangor and Aroostook Railroad, one-fourth mile north of milepost

155, one-third mile north of Robinson Station. 

N. In field, southwest of Boynton's house, section from brook toward northwest. 

0. From one-half mile north of schoolhouse, on west side of Mars Hill (near

Boynton's), to top of the mountain. 

. P. On east-west road, along north base of Mars Hill, beginning on lot 32 and

extending to Maine-New Brunswick line.

1297. .MONTICELLO (TOWNSHIP 8, RANGE 1). ' 

, A. Cut on Bangor and Aroostook Railroad at milepost 144 from Oldtown, 8 miles

south of Harvey's. 

B. Cut on Bangor and Aroostook Railroad, 1,400 feet south of milepost 144, 1

mile south of Harvey's siding.

C. Two-thousand feet south of milepost 144 from Oldtown, 4.5 miles north of 

Monticello Station.

1298. BRIDGEWATER (TOWNSHIP 9, RANGE 1).

A. On Bangor and Aroostook Railroad, 1 mile south of Robinson Station, 1,500 

feet south of milepost 154 from Oldtown.

1299. EASTON (TOWNSHIP 11, RANGE 1).

A. On Easton-Fort Fairfield road, 2 miles north of Easton Center, near fork in

road at Wheeler's blacksmith shop.

B. In field east of Easton-Fort Fairfield road, 1£ miles north of Easton Center. 

C. In Centerville, just north of Easton Center. 

D. On road from Easton Center to Spragues Mill, one-half mile east of latter.

1385. FORT FAIRFIELD (TOWNSHIPS 12 AND 13, RANGE 1).

A. In field south of Presque Isle-Fort Fairfield road, 7 miles east of Presque Isle

and 1 mile east of west line of Fort Fairfield. 

J3. On road running southeast from Fort Fairfield and then turning south between

Johnson and Fitzherbert brooks, 2 miles from Fort Fairfield. 

C. On east-west road, one-half mile east of railroad crossing, which is one-half

mile north of Fairmount Station. 

D. On first east-west road north of Fairmount Station, between Fort FairfieldEaston road and Bangor and Aroostook Railroad.

1386. NEW LIMERICK AND LUDLOW (TOWNSHIP 6, RANGE 2).

A. On Carys Mill-New Limerick road, opposite middle of Nickersbn Lake. Several outcrops.

B. On Carys Mill-New Limerick road, opposite western end of Nickerson Lake. 

C. Outlet of Drews Lake, north side stream, just below bridge at upper mill. 

D. Outlet of Drews Lake, north side stream, 10 feet east of 1386 C. 

E. Outlet of Drews Lake, south side stream, on New Limerick-Linneus town

line (? or in Linneus). 

F. On New Limerick-Ludlow road (running along the south side of Bangor and

Aroostook Railroad), 1,200 feet south of railroad crossing. 

G. Cut on Bangor and Aroostook Railroad, at milepost 188 from Oldtown, 1

mile east of Ludlow Station. 

H. Cut on Bangor and Aroostook Railroad, at east end switch at Titcomb's siding,

0.8 mile east of Ludlow Station. 

K. Cut on Bangor and Aroostook Railroad, at milepost 120 from Oldtown, 1.2

miles west of New Limerick. 

L.- In field south of Bangor and Aroostook Railroad, about one-half mile east of

milepost 119 from Oldtown.
WILLIAMS.] LOCALITIES OF OUTCROPS. 195

j 1387. PRESQUE ISLE, SOUTH ONE-HALF (TOWNSHIP 11, RANGE 2).

A. Cut on Bangor and Aroostook Railroad, one-half niile south of station at 

Presque Isle.

B. In wagon road (Presque Isle to Houlton), three-fourths mile south of Presque 

-s Isle.

C. Side of road at sharp turn, about three-fourths niile east of Spragueville, on 

\ .road leading to Houlton from Spragueville.

D. Quoggy Joe Mountain.

v E. Side of road and in field just east of bridge on stream running from Quoggy 

Joe Lake at Spragueville.

F. In road on hill about l£ miles northwest of Spragueville.

1388. PRESQUE ISLE, NORTH ONE-HALF (TOWNSHIP 12, RANGE 2).

A. In road on south bank of Aroostook River, one-half mile east of Presque

Isle-Mapleton town line. 

B. On north Presque Isle-Ashland road, three-fourths mile northwest of Presque

Isle. 

C. On north Presque Isle-Ashland road, about 1£ miles northwest of Presque

Isle, just east of junction with road going to center of Mapleton. 

D. On Presque Isle-Ashland road (north one) about l£ miles northwest of Presque

Isle, ju,st west of junction of road to center of Mapleton.

" E. One-fourth mile east of Presque Isle-Mapleton line, on a road which turns west 

from north Ashland-Presque Isle road, 1$ miles northwest of Presque 

y Isle. 

') H. On south of Presque Isle-Fort Fairfield road, 2 miles from Presque Isle,

where road comes nearest river bank.

K. On Presque Isle-Fort Fairfield road, 3$ miles northeast of Presque Isle. 

L. In field south of Presque Isle-Fort Fairfield road, one-half mile west of east

Presque Isle line. 

M. North bank of. \roostook River, just below covered road bridge, north of

Presque Isle.

N. South bank of Aroostook River, one-fourth mile below railroad bridge, north 

of Presque Isle.

1389. CARIBOU, SOUTH ONE-HALF (TOWNSHIP 13, RANGE 2).

A. Opposite Caribou on east side of Aroostook River, at exposures below dam 

and fishways.

C. Southwest of Collins's milldam, on Caribou Stream, south side of stream.

D. At mouth of Madawaska River, on east side of bridge and north bank, just 

beyond bridge foundation.

E. At Calkins's limekiln, in lot beyond river road and a few rods from main 

road back of house.

F. On road from Washburn, south of Caribou Stream, near angle of road running westward in Woodland

1390. CARIBOU, NORTH ONE-HALF (TOWNSHIP 14, RANGE 2).

A. Outcrops along north bend of Aroostook River", by railroad cutting beyond

the village. 

C. On Canton-Limestone road, east-west, on east side of Madawaska River at

the bridge.

D. Near corner road from Hardwood Creek Valley, turning eastward toward 

Limestone.

1391. OAKFIELD (TOWNSHIP 5, RANGE 3).

A. Cut on Bangor and Aroostook Railroad, 1 mile east of Ashland Junction. 

B. Cut on Bangor and Aroostook Railroad, 400 feet east of milepost 113, 2 miles

east of Ashland Junction.

C. Cut on Bangor and Aroostook Railroad, 200 feet west of milepost 114, 2.8 miles 

\ east of Ashland Junction. .
196 CONTRIBUTIONS TO THE GEOLOGY OF MAINE. [BULL. 165.

1392. SMYRNA (TOWNSHIP 6, RANGE 3).

B. Cut on Bangor and Aroostook Railroad at Timony road, about 3 miles east

of Ashland Junction (22 feet of west end of this cut is in 1391.) 

C. On station grounds of Smyrna Mills and just south along track. 

D. Cut on Bangor and Aroostook Railroad (Ashland branch), 1,000 feet south

of milepost 116 from Oldtown, 3 miles north of Smyrna Mills Station.

Extends to rnilepost 115. 

E. Cut on Bangor and Aroostook Railroad (Ashland branch), one-half mile north

of milepost 114 from Oldtown, 1£ mile north of Smyrna Mills. 

F. Cuts on Bangor and Aroostook Railroad (Ashland branch), just south of

bridge, Smyrna Mills. 

H. Cut on Bangor and Aroostook Railroad (Ashland branch), 600 feet north of

road crossing at Smyrna Mills. 

K. Cut on Bangor and Aroostook Railroad, 1,000 feet east of Timony road

crossing. 

L. Cut on Bangor and Aroostook Railroad (Ashland branch), south of milepost

117, 4 miles north of Smyrna Mills. 

Q. Ludlow granite quarry.

1393. WEEKSBOEO (TOWNSHIP 7, RANGE 3). 

A. At Weeksboro Station. 

B. At and near milepost 122 from Oldtown (Ashland branch), 0.8 mile south of

Weeksboro. 

C. Cut on Bangor and Aroostook Railroad, 1,000 feet north of milepost 118 from

Oldtown (Ashland branch), 2.8 miles south of Weeksboro.

1394. TOWNSHIP 9, RANGE 3.

A. On south branch of Presque Isle, 1 mile below Ripps Dam, 12 miles south of

Tweedy's in Chapman (1099 A). 

1099. CHAPMAN (TOWNSHIP 11,.RANGE 3).

A. On right bank of South Branch of Presque Isle River, about 1 mile from

Chapman, south line; 1 mile west of Tweedy's. 

B. On road from Presque Isle to Chapman, 7 miles from Presque Isle. 

C. Edmunds Hill. . 

D. Hill west of road along west side Chapman (Swanback road), three-fourths

mile south of Mapleton line. W. H. Littlefield's farm. 

E. On Swanback road at schoolhouse, one-half mile south of Alder Brook

crossing. 

F. End of Swanback road running along western line Chapman, 1£ miles south

of Alder Brook crossing. 

G. Near top of hill, at large square house, 1 mile south of Littlefield's, on

Swanback road.

H. Hobart Hill (north two-thirds of hill is in Mapleton). 

1395. MAPLETON (TOWNSHIP 12, RANGE 3).

A. Granite hill on lot 15,. near the Aroostook River road. Locally known as

- Munson's granite. * 

B. Group of hills between the State road and the Aroostook River, 2 miles west

of east Mapleton line.

1. On lot 14, a little west of granite (1395 A).

2. On southeast corner of lot 13.

3. On northeast corner of lot 23.

4. On northwest corner of lot 24.

C. Section along upper Ashland-Presque Isle road (State road), running west 

from Mapieton-Presque Isle line.

1. Hill just west of township line.

2. Seven hundred feet north of road, on lot 27.
WILLIAMS.] LOCALITIES OF OUTCROPS. 197

1395. MAPLETON (TOWNSHIP 12, RANGE 3) Continued.

C. Section along upper Ashland-Presque Isle road (State road), etc. Cont'd.

3. One thousand feet southwest from schoolhouse on lot 44.

4. One rnile west of Mapleton-Presque Isle line.

5. One and one-half miles west of Mapleton-Presque Isle line.

6. Seven miles west of Presque Isle, a well on Hale's farm. 

D. Section on road running northeast from Mapleton Village (Balls Mills) to 

North Ashland-Presque Isle road.

1. Three miles from Balls Mills, at turn in road, in field.

2. Five hundred feet east of 1395 D, in field.

3. In road west and in field east of road corner, 1$ miles south of State 

road.

E. Section running east-west for one-fourth mile on north part of lot 89, near 

Presque Isle River.

F. Just west of Mapleton-Presque Isle town line, on road branching from north 

Ashland-Presque Isle road 1$ miles northwest of Presque Isle.

G. On road which branches from north Presque Isle-Ashland road 2$ miles 

west of Presque Isle, hill l£ miles long, beginning 1J miles east of Winslow's farm, and extending south and west.

H. Section on road which branches from Mapleton-Presque Isle road, where it 

crosses north branch of Presque Isle River and runs southwest to Edmunds 

Hill.

1. One-fourth mile south of Mapleton road, in road and fields.

2. Old quarry, near bank of river, on lot 111.

3. On northeast corner lot 110, one-fourth mile north of road.

4. One mile south of Mapleton road. 

K. On south Presque Isle-Ashland road, at road junction one-third mile west

of Mapleton-Presque Isle line. 

L. Section on Presque Isle-Mapleton road, running west from the bridge over

the north branch of the Presque Isle River to Balls Mills.

1. In road one-eighth mile west of bridge.

2. In road on west slope of first hill.

3. At west base of hill.

4. At road junction, 1$ miles east of Balls Mills.

5. East slope of hill, 1J miles east of Balls Mills.

6. In road and in field south of road, 1} miles east of Balls Mills, on lot 99.

7. At road junction, 1 mile east of Balls Mills.

M. Along the road and extending north to the river, on lots 90 and 91. 

N. South half of lot 101.

0. Section on road running north-south along west side of lot 99. 

P. Section running east-west across lots 106 and 107. 

Q. Section on north-south road between lots 115 and 116.

1. In road, one-half mile north of Mapleton-Chapman line.

2. In road, 1,000 feet north of 1395 Ql.

R. Section in road which branches from Mapleton-Presque Isle road, 1£ miles 

east of Balls Mills, and runs along base of hill on lot 99. Outcrops begin 

near Mapleton road and extend south for one-fourth mile.

1396. WASHBUKN (TOWNSHIP 13, RANGE 3).

B. At mill on Salmon Brook, southeast corner of Washburn Township, north of

Aroostook..

C. On road near middle of township, running northward from center. 

D. On road near middle of township, running northward from center. 

E. On road near middle of township, running northward from center. 

F. At Washburn Ferry, north bank of Aroostook River.
198 CONTRIBUTIONS TO THE GEOLOGY OF MAINE. [BULL.165. ""

1396. WASHBUEN (TOWNSHIP 13, RANGE 3) Continued.

G. Right bank of Aroostook River, a few rods east of the Wade-Washburn town ' 

line. (Probably reaches into Wade.)

2. On brpw of hill in road south of and near 1396G.

H. Three-fourths mile below Washburn Ferry, north bank of Aroostook River. - K. North bank of Aroostook River, 1£ miles west of East W.ashburn line. Near 

1395A.

1397. WOODLAND (TOWNSHIP 14, RANGE 3). 

A. Outcrop on road (main road from Caribou west through Woodland to Perham), a few rods west of crossing of north branch of Caribou Stream.

C. On main road at Mclntyre Hill, outcrop at corner of road running south.

D. On main road near center of township, before reaching road running southwest.

E. On road from center of Woodland to Washburn and about a mile south of 

the Caribou-Perham road, sloping to the west of Caribou Stream.

F. Limestone outcrop along main Caribou-Woodland road, about a mile west of 

center of township, and on the east slopes of the valley of west branch 

of Caribou Stream.

G. On road going south about a mile east of west town line, and one-half to 

three-fourths mile south of the Caribou-Woodland-Perham road; outcrops 

appearing also along main line to the Perham town line, where there is 

station G4.

K. On road obliquely crossing northeast corner Woodland and direct to New 

~ Sweden, at a point 1£ miles from eastern boundary of town, and 1 mile 

east of crossing north branch Caribou Stream, 2 miles south of WoodlandNew Sweden line.

L. Small mill about one-fourth mile west of K.

M. About 1|~ miles farther northwest than L, on road running along east side of 

North Branch Caribou Stream, and about 1 mile south of town line.

N. On north-south road near center of town, within one-half mile of north line 

of town, and near crossroad.

S. At corner of road running directly west, near lower edge of Woodland Township, beyond middle westward, where road turns south. 

1096. NEW SWEDEN (TOWNSHIP 15, RANGE 3).

A. On middle road from Woodland to New Sweden, near the township line, on

west side of road.

B. Outcrop on south side of road, going down hill from post-office a few rods.

C. Opposite Baptist Church, below post-office to the west.

D. On road one-fourth mile west of 1096C.

E. At corner of road turning up hill to north, about 1 mile from south line, and 

1 mile east of west line of town.

F. On north-south road, about 1£ miles north of 1096E, near middle north-south 

line of township, and within 1 mile of west line.

G. On .road and in field to north of road at head of Bearsley Branch, near the 

west line of New Sweden, outcrops extending from the main road running 

north-south to beyond the New Sweden line to west. ,

H. On Olivenbaum farm, in northeastern part of township, in field in back party 

of farm. Farm facing east and west road, at summit,between sources of the 

north branch of Bearsley Brook, and a stream running south and then westward and emptying into the outlet of Little Madawaska Lake. The farm 

marked by a single large pine tree, and stone pile built about its root.

I. In road opposite Olivenbaum farm.
WILLIAMS.] LOCALITIES OF OUTCROPS. 199

1096. NEW SWEDEN (TOWNSHIP 15, RANGE 3) Continued.

J. In field south of road, east of Olivenbauni house and still on the slopes of the

north branch of Bearsley Stream. 

K. In field south of road, east of Olivenbauni house and still on the slopes of the

north branch of Bearsley Stream. 

L. On side of road running northwest from Pedersons,toward Madawaska Lake,

beginning opposite the dam above Pedersons, Jerntland post-office. 

M. Off the main east-west road, in northern part of township, southward about

middle of township, on hill on west side of Bearsley Branch. 

0. Along eastern road, from corner at north where it turns toward Pedersons

and Madawaska Lake to the New Sweden main east-west road, a distance

of about 4 miles. 

P. Along eastern road, from corner at north where it turns toward Pedersons

and Madawaska Lake to the New Sweden main east-west road, a distance

of about 4 miles. 

Q. Passing along the north-south road in eastern New Sweden, crossing the

watershed into the sources of north branch of Caribou Stream, turning

corner by the mill on outcrop showing first traces of the calcareous element

in the slates. 

R. In picnic ground south of main east-west road from New Sweden post-office,

outcrop of iron and manganese stained slates. 

S. Going east on main east-west New Sweden road beyond the picnic ground

corner, over a mile, on the rise from the long summit marsh, outcrops of

calcareous shales. 

T. At corner of road, main east-west New Sweden road, turning south, outcrops

of shales. 

V. On road near crossing of New Sweden-Woodland line, between the sources

of Otter Brook and Hardwood Creek. 

1398. ST. CEOIX (TOWNSHIP 8, RANGE 4).

A. Cut on Bangor and Aroostook Railroad and falls on St. Croix River at milepost 132. 

B. Cut on Bangor and Aroostook Railroad, north of milepost 131, 1 mile north

of St. Croix Station.

C. Falls on St. Croix River, three-fourths mile south of St. Croix Station. 

1416. GHISWOLD (TOWNSHIP 9, RANGE 4).

A. Cut on Bangor and Aroostook Railroad (Ashland branch) at mill seat, 1J

miles south of Griswold. ' , 

B. Rapids in St. Croix River at mill seat, 1$ miles south of Griswold. 

1399. TOWNSHIP 11, RANGE 4. 

B. Hedgehog Mountain. 

1415. CASTLE HILL (TOWNSHIP 12, RANGE 4).

A. 6. Near middle of east side lot 32, on east bank of brook.

7. In field, at corner of woods, 700 feet west of A 6.

8. Three outcrops at large stone piles on lot 32, about halfway between A 7 

and A 9.

9. Five hundred feet north of A 10.

10. Several exposures in field, southwest corner lot 32, at junction of roads. 

B. Section along ridge in the woods on lot 31, Castle Hill.

1. West of road (about 800 feet) and near north line of lot 31.

2. On west brow of hill on lot 31, about east of mouth of Welts Brook.

3. Little north'of B 2.

4. Hill on northwest corner of lot 31, or on lot 30, overlooking the river. 

Section is on steep northwest face.
200 CONTRIBUTIONS TO THE GEOLOGY OF MAINE. [BULL. 165.

1415. CASTLE HILL (TOWNSHIP 12, RANGE 4) Continued. -

C. All of the field occupying the southeast corner of -lot 31, Castle Hill, at the 

junction of the State road with the road running north; south along east 

side of Castle Hill Mountain.

1. Low hill occupying extreme southeast corner of lot 31. 

2; Ledge in open field north of C and directly across the road from 1415 A 9. 

D. Section along the State road from where it crosses Castle Hill ridge to east 

line of township. . "

1. On Castle Hill- Ashland road, one-half mile west of junction with northsouth road east of Castle Hill Mountain, and about 1£ miles west of 

Castle Hill post-office.

2. Side of road on hill three-fourths mile west of Castle Hill Hotel.

3. In road, one-half mile west of Castle Hill Hotel.

4. In road, 1 mile east of Castle Hill Hotel.

5. In road, l£ miles east of Castle Hill Hotel. 

E. McDonalds Hill, on lots 53, 54, 55, and 78, Castle Hill. 

1. On side of hill, a little north of center of lot 54. 

/2. On south brow of the main hill, mostly on lot 78.

F. Section along north-south road which branches from State road about 1 mile 

west of Castle Hill Hotel, and runs east of the Castle Hill-Haystack ridgel

1. East side of road on northwest corner of lot 68.

2. Both sides of road (and along stream on lot 79) near northwest corner 

of lot 80 (Turner's house) .

3. On bank of brook, near middle of west line of lot 80.

G. Section along brook, near junction of north-south and east-west roads, in lot 

103 and 104, nearly all in the latter.

1. On lot 103, west of road along east side of Castle Hill-Haystack ridge.

2. Following down stream to east, across lot 104.

H. Footpath, beginning at Mapleton- Ashland road, 1 mile east of Haystack and 

running north 1 mile to junction of roads at schoolhouse, on lot 103.

1. Low hills on southwest corner of lot 128, on east side of path.

2. Southeast from schoolhouse and across road into lot 116. 

J. Both sides of road and in fields along Ashland-Presque Isle road, 2^ miles

east of Castle Hill post-office, and just west of junction with north-south

road at blacksmith shop.

K. On Dr. Dow's farm and in road near his house (Mapleton). 

L. On J. W. Dudley's farm, 2$ miles west of Mapleton Village.

2. > In field southwest of house.

3.J - -

4. In ravine west of barn, on lot 105.

5. Along ravine running north-south, south of east-west road pas.t Dudley's

and about on line between lots 117 and 118. 

M. On lower Presque Isle- Ashland road from Dr. Dow's house to 1 mile east of

Haystack Mountain.

N. Haystack Mountain and immediate vicinity. 

0. At junction of east-west road (Dudley's) with northwest road along east side

of Welts Brook, near southwest corner of lot 102.

1. In and north of road, at extreme southwest corner of lot 102.

2. One-half mile north of road junction, and -on west side of road, on

lot 101. 

P. On north of Ashland-Presque Isle road, just east of Sheridan-Castle Hill line.

1. At schoolhouse, 1£ miles east of Sheridan line. 

R. Hill on north Ashland-Presque Isle road, 2 miles from Sheridan line.
WILLIAMS.] - LOCALITIES OF OUTCROPS. 201

1415. CASTLE HILL (TOWNSHIP 12, RANGE 4) Continued.

S. North bank of Aroostook River, 1 mile below mouth of Beaver Brook.

T. Both sides of Aroostook River, and in stream bed at Castle Hill Mountain,

between mouth of Welts Brook and Castle Hill-Wade line. 

V. Section along west side of McDonalds Hill, in and near north-south road 

which follows east side of Welts Brook.

1. Between road and Welts Brook, at west base of McDonalds Hill.

2. In road, 700 feet south of McDonalds Hill.

3. Hill east of road and about middle of lot 90t west side of hill. ' 

X. Outcrops on lot 89, southeast corner, included between two branches of

Welts Brook and the north-south wagon road. 

Y. Near east bank of Welts Brook, on south side line of lot 100, in a footpath

made by continuing the Dudley road west to the brook. 

Z. Group of hills to the northeast of Haystack, on lots 114, 115, 126, 127.

1. Southeast brow of Pyles Hill, lot 115.

2. On side of hill, about one-eighth mile southwest of Z 1.

3. Top of hill which forms highest point northeast of Haystack and 

about one-half mile from the mountain.

1417. WADE (TOWNSHIP 13, RANGE 4).

A. In road on south bank of Aroostook River, a few rods west of Wade-Washburn town line. > 

B. In field just north of road on south bank of Aroostook River, about one-half

mile west of Wade-Washburn town line. 

C. On Mr. Donelly's (?) farm, between road and south bank of Aroostook River,

about 1 mile west of Wade-Washburn town line.

D. In road on south bank of Aroostook River, 2,000 feet west of 1417 C. 

F. On right bank of Aroostook River, just below rips, at mouth of Gardner Creek

(or Upper Salmon Brook), 1,000 feet west of 1417 G. 

~ G. On right bank of Aroostook River, just below rips, at mouth of Gardner Creek

(or Upper Salmon Brook). 

H. In road running from Wade to Castle Hill (about 3 miles from eastern line

of these townships), just north of Wade-Castle Hill line. 

K. North bank of Aroostook River, 1£ miles below mouth of Gardner Creek. 

L. In bed of Gardner Brook, one-half mile from its mouth. 

M. Little stream back of house on lot 17.

1418. PERHAM (TOWNSHIP 14, RANGE 4).

H. On the east-west road in northern part of Perham, about 1 mile from 

northern town line, and nearing the valley of the stream which is source 

of Salmon Branch.

1. At schoolhouse; slates.

2. On side hill of valley going down; sandstone.

4. On rise of valley on west side; sandstone.

5. One-fourth mile farther; sandstone.

1419. MADAWASKA LAKE (TOWNSHIP 16, RANGE 4).

A. Along east shore of lake, south of Jones's cottage. '

B. Beyond Jones's cottage on lake shore, outcrop of banded red and green slates;

bedding seen and showing slate lying upon the sandstone of 1419 A.

1. Sandstone with round balls (concretions) in it. 

, 2. Red and green slate lying outside it, on the shore and beyond in lake,

at its edge. 

1338. TOWNSHIP 9, RANGE 5.

A. Cuts on Bangor and Aroostook Railroad (Ashland branch) at milepost 140

from Oldtown, 3.7 miles south of Masardis.

B. About 5 miles southwest of Masardis, at junction of Oxbow road with one 

running south through 85. Same material all along road.
202 CONTRIBUTIONS TO THE GEOLOGY OF MAINE. [BULL. 165.

1337. MASAKDIS (TOWNSHIP 10, RANGE 5). -

A. 1. In field north of road, three-fourths mile west of Masardis, on river bank.

2. In road west of hotel on hill. 

C. On south bank of Aroostook River, near Bangor and Aroostook Railroad

station, Masardis. 

1098. ASHLAND (TOWNSHIP 11, RANGE 5).

A. 1. Ashland Village, opposite Ashland Hotel.

2. In Ashland Village, on road from hotel to railroad station.

3. East side of road, 400 feet south of Ashland Hotel.

4. On east bank of Aroostook River, just below the mouth of Big Machias,

three-fourths mile above Ashland bridge.

B. On south Ashland-Presque Isle road, about 4£ miles east of Ashland. 

C. On south Ashland-Presque Isle road, a few rods west of Ashland. 

D. On north Ashland-Presque Isle road, extending from Ashland to north Ashland town line. ' i 

E. On Big Machias River, at milldam near mouth.

F. On Mr. Oilman's farm, three-fourths mile south of Ashland, on Masardis road. 

H. On east-west road which branches from Masardis road, three-fourths mile 

south of Ashland (at Oilman's farm), in field just east of railroad crossing, just west of 1098 F.

K. In field east of road on Winslow's farm, 1£ miles south of Ashland. 

L. 1. In road near corner, three-fourths mile northeast of railroad crossing, near

milepost 152 from Oldtown, about 3£ miles south of Ashland. 

2. In road west of a field southwest of schoolhouse, 2 miles south of Ashland,

on Masardis road.

M. 1. In field west-of .road on C. G. Read's farm, 3£ miles south of Ashland. 

2. From newly dug well, 1£ miles north of Ashland-Masardis line, on road

east of Aroostook River, one-eighth mile southeast 1098 M 1 . 

1097. SHERIDAN (TOWNSHIP 12, RANGE 5).

A. On north Ashland-Presque Isle road, a few rods north of Sheridan south line. 

B. South side of north Ashland-Presque Isle road, one-fourth mile north of

Sheridan south line.

C. North side of road, a few rods east of Alder Brook, at foot of hill. 

D. In north Ashland-Presque Isle road, at top of hill, 1 mile east of Alder 

Brook'(?).

E. Right bank of Aroostook River, a short distance below mouth of Alder Brook.

F. South of upper Ashland-Presque Isle road at Frenchville store and church.

H. On right bank of Aroostook River, about 1 mile west of east Sheridan line, 

on Alley's farm called "Alley's grindstone."

K. On north Ashland-Presque Isle road, one-eighth mile west of east Sheridan 

line.

L. South bank of Aroostook River, one-half mile below Ashland Mill.

M. On south bank of Aroostook River, 1% miles below Ashland Mill.

N. North bank of Aroostook River, 2 miles below Ashland Mill.

0. North bank of Aroostook River, 1$ miles below mouth of Alder Brook.

P. Northwest bank of Aroostook River, at upper end sharp bend, 5 miles from 

Ashland Mill. (500 feet upstream from 1097 R.)

R. On north bank of Aroostook River, lower end of sharp curve, 5 miles from 

Ashland Mill (?), three-fourths mile west of 1097 H. 500 feet east of 1097 P.

S. South bank of Aroostook River, one-half mile above east Sheridan line. 

1340. GAKFIELD (TOWNSHIP 11, RANGE 6).

A. First long hill on Ashland road, West and .gouth along Big Machias, beginning one-fourth mile southwest of mill.
WILLIAMS.] LOCALITIES OF OUTCROPS. 203

1340. GARFIELD (TOWNSHIP 11, RANGES) Continued.

 B. On road along Big Machias River, one-fourth mile west of fork turning south

along Aroostook River. 

C. On Mr. Hugh's farm, 3£ miles from Ashland, on road along the south side of

Big Machias River.

D. Right bank of Big Machias River, 1 mile above mouth of Greenlow Brook. 

E. On left bank and in bed of Big Machias River, about 1 mile above mouth of 

Greenlow Brook,, west of 1340 D.

NEW BRUNSWICK.

The following stations are east of the Maine border in New Brunswick:

7. Cut on Houlton branch Canadian Pacific Railroad, 3£ miles west of Debec Junction, Carleton County.

8. On road running south from McKenzies Corner, 1 mile south of railroad crossing, 

Carleton County.

9. On Beinis's farm, 1 mile west of Ivys Corner, south of Debec Junction.

10. One-fourth mile south of Ivys Corner, along Pocornoonsliine Creek, Carleton 

County.

11. On west bank of Pocomoonshine Creek, one-half mile south of Ivys Corner.

12. Cut on Canadian Pacific Railroad, one-fourth mile south of crossing of road from 

lower Woodstock, about 3 miles south of Debec Junction.

13. Cut on Canadian Pacific Railroad at curve, one-half mile south of Debec Junction.

14. Cut on Canadian Pacific Railroad at Teeds Mill (Topley's), between Debec Junction and Woodstock.

15. At milldam, Teeds Mill (Topley's), between Woodstock and Debec Junction.

16. Falls on Bull Creek, one-half mile below Teeds Mill (Topley's).

17. One-fourth mile below falls on Bull Creek, 1 mile below Teeds Mill (Topley's).

18. Cut on-Canadian Pacific Railroad, Teeds Mill (Topley's), 300 feet north of New 

Brunswick 14.

19. In bed of Meduxnekeag River at Woodstock.

20. On Florenceville-Centerville road, one-half mile west of Florenceville, Carleton 

County.

21. On Florenceville-Centerville road, 1$ miles west of Florenceville, Carleton County.

22. On Florenceville-Centerville road, 2J miles west of Florenceville, Carleton County.

23. In village of Centerville, Carleton County.

24. One and one-half miles north of Florenceville, just west of corner where two 

churches and a schoolhouse stand.

25. On west bank of St. John River at Florenceville bridge.

26. Grand Falls.

27. Aroostook Junction, Canadian Pacific Railroad.

28. Falls on the Aroostook River, near its mouth.

29. On road running east-west along north base Mars Hill, continued one-half mile 

into New Brunswick.

o

INDEX.

A. Page. 

Acidaspis ............................ 42,43,44,48

Actinopteria............_ .......... 42

Agnostus tuberculatus. ............. 85

Alder Brook, localities examined near. 202,203 

"Alley's grindstone," locality examinedat.--. .................... 202

Sheridan sandstone at.............. 132-133

Ami, H. M., fossils identified by....... 37,38,41

Amphigenia. ...... .... ...... 91

Anadontopsis........--.-.. ......_..- 40

Analyses, andesites................. 171-172,188

bostonites...................____ 166

calcif erous sandstone . .......... 139,188

diabase.......-....,..'- ...... 176,179,188

quartz-trachytes ................. 166,167,188

rhyolites .........".. ...... 155,188

teschenites .......................... 183,188

volcanic tuff- ...................... 124,188

Anastrophia....-................_..... 43

Anatina.................................. 34

Andesite, cleaved, plate showing....... 101

Andesite ash beds, occurrence of....... 175

Andesites, analyses of.............. 171-172,188

occurrence and character of. 111-114,168-175 

Andesitic breccia, plate showing....... 112

Andesitic lava, plate showing .......... 112

Anoplia..........-.. .................. 42

Anoplotheca........---..-..--.......... 47,48,53

Anoplotheca hemispherica ............. 49

Anticosti group,age of.................. 23,24

Aplite, occurrence and character of... 149 

Aporoxylon......'............ ...._. 31

Area ..................................... 86

Arenaceous limestones, occurrence and

character of.....'................. 140-141

Arisaig, Nova Scotia, fossils from...... 40-41

Arisaig rocks, fauna of ........._.... 86-87

Aroostook County, geology of volcanic

areain ........................... 93-188

localities examined in............... 193-202

new Paleozoic fossils from.......... 44792

Paleozoic terranes of................ 21-27

plate showing volcanic area in ..... 105

Aroostook Falls, diabase at......... 115,175-177

Aroostook Junction, localities examined

at................................. 203

Aroostook limestone, age of ....... _ 21,44-45

new fossils from............. ..... 44-45

occurrence and character of...__ 141-143 

plates showing .................._. 140,142

Aroostook Eiver, aplite on .___..._ 149 

calciferous quartzitic sandstones

on?..........,.................... 138-139

Page. 

Aroostook River, granite on............ 105-106

limestones on........................ 141-143

localities examined on and near.... 195,

197,198,201,203,203 

manganif erous iron slates on....... 145

metamorphism on................... 151

Paleozoic fossils from ...... ..... 44

sandstones at........................ 137-138

Ashland, fossils from.................... 29,53

localities examined near .... .... 203

Ashland Junction, localities examined

at. .... ............... 195,196

Ashland limestone, age of .........._ 21,51,52

features and fossils of............... 52-54

occurrence and character of........ 143

Ashland shales, ageof................ 21

features and fossils of............... 49-51

Ashland Township, volcanic conglomerate in .......................... 127,129

volcanic tuff in ...................... 121,125

Ashland village, features of rocks at... 49 

fossils from................. ... 50,52,53

fossiliferous limestone at and near. 143 

localities examined near............ 202

Ashland-Sheridan road, volcanic tuff

on..... .. . 121-122,125-126

Athyris.................... .... . 29,31,55

Athyrisbella. ...................... 32

Athyris blancha................... .. 32

Atrypa... .. ........,.... .... 29,

31,32,33,34,35,36,37,39,47,49,50,52,54,55 

Atrypareticularis ....._.............. 38,52

Atrypina...- --.-.-..- . 63,55 

Augite-andesite, occurrence and character of ... ..... ............. 169-172

Autodetus.... ....... ........... 42

Avicula................................... 28,

29,30,33,34,36,38,41,53,79,80/86,89,89,90,91 

Aviculopecten............. .......... 43

B.

Balls Mills, localities examined at...... 197

Bailey, L. W., cited on age of Mapleton

sandstones......_.............. 137

cited on Aroostook limestones ..... 141

cited on occurrence of syenite...... 149

titles of papers on Maine geology

by.......-.... ............... 104 (note)

Bailey and Mclnnes, Canadian rocks 

containing Oriskany fauna reported by ................_.... 37

fossils identified by.................. 33

Baileys Landing,Missouri, fossils from. 43

205
206 INDEX.

Page.

Bangor and Aroostook Railroad, localities examined on ................ 193,

194,195,196,199,201,202 

Barrois, Charles, cited on equivalence 

of Lower Helderberg and Hercynian faunas....... ..... 81

Bar yphy Hum-.----.. ................ 44

Battus............, . -- ....- 86

Batttis tuberculatus...-......-.-.---..--- 85

Bayley, W. S., fossils recovered and

preserved by.--.....----.-.------ 103

Beachia ...............-........... .. 92

Bean Brook, fossils from................ 90

Bearsley Branch of Madawaska River,

volcanic conglomerates on....... 127-128

Bearsley Brook, localities examined on

and near ..................... 198

Bearsley Stream, localities examined on

and near ............. - ---- 198,199

Becraft Mountain, New York, fossils

from....... .................... 42

Beecher, C. E., cited on horizon of fossiliferous rock at North Haven. 36 

fossils identified by................... 36

Bellerophon .......-.. 36,40,41,42,48,79,80,86

Bellerophon carinatus ............... . 85

Bellerophon expansus..... ...... 83,85

Bellerophon globatus ... ...... 85

Bellerophon murchisonae ........... 85

Bellerophon striatus ............ 85

Bellerophon trilobatus ................... 83,85

Beyrichia.....-...- ----- 29,34,35,36,41,79,86

Beyrichia pustulosa. ..^................. 85

Beyrichia tuberculata .... .....--. 83,85.

Big Brassua Lake, fossils from...... 91-92

Big Machias River, localities examined

on _.._..._.-..--.-- .. .-.- 202 

Billings, E., cited on age of fossils from

Square Lake.. .... ....... 32

cited on Chonetes................... 84

cited on distinctive characters of

Rhynchonella aspasia... ......_ 70

cited on horizon of rocks at Pembroke ............................ 29

fossils identified by.... .29,30,31,33,39-40

quoted on fauna from Masardis.--. 52 

Bilobites.----.--.------ ............... 48,55

Bilobitesbilobus .:............ .-.-. 44

Birch-bark weathering of rhyolite,plate

showing...... .,-..- 108

Bonaventure formation, age of....._..- 23

Bostonites, analyses of..... . 166

Brassua Stream, fossils from....... 92

Breccia, andesitic, plate showing....... 112

Bronteus. ............- ........ .31,32,53,56

Bronteuspompilius..................... 52

Bryozoon. .- ---- ----- . -... 32

Buthotrephisgracilis...... . ......

C.

Calciferous sandstone, analyses of..... 139,188

occurrence and character of -------- 138-139

Callopora ............................... 38

Calloporella.........--.. .............. 38

Calymene-..-..-- ---.-.-... 28,29,36,37,41,50 

Camarotcechia.-.. ................ 57,58,59-67

iampbell River, New Brunswick, .fossils from...................... 37

Canada, Paleozoic fossils reported from 37-41 

Paleozoic rocks of (classification) .. 22-24 

Canadian Pacific Pailroad, localities examined on........................ 193,203

Cardiola.................................. 46

Cardiola interrupta .-..-.__-...._ 46

Caribou,fossils from ..._ _......._ 44,48

localities.examined near.___... 195 

Caribou River, sandstones on........... 137-138

Caribou Stream, localities examined on

and near ......................195,198,199

trachyticrock from................. 164

Carkhuff, N. W., illustrations made by. 13 

Caryocrinus ornatus.................... 51

Castle Hill,andesites at. .... . 114,174-175

f ossilif erous limestone at........ _ 143

geologic map of area at............. 120

localities examined at........... 199,200,201

manganiferous iron slates at....... 145

volcanic tuffs at............. 120-121,122-125

Centerville, New Brunswick, localities

examined near.. ._. .._..... 203

Centronella........._........_...... 43

Cerauriis............_......_._..... 36

ChaBtetes.............................. 37,55

Chaleur, Bay of, fossils from............ 33

Chapman, localities examined near.. _ 196 

Chapman sandstone, age of ............. 21,22

correlation of.__. .- -..._._ ' 27 

equivalents of fauna of.............. 87-88

features and fossils of_...__ _ 78-88 

fossil plants of....................... 87

occurrence and character of._..... 133-134

Chapman Township, andesites in....... 112,113

sandstone in ...._................... 133-134

trachyte in ....................... 110,162-163

Chatard.T.M., analysis by.............. 166 

Chatte River limestones, age of ........ 23

Chemical analyses. See Analyses. 

Cheirurus................................. 33

Cheirurus tarquinius................... 62

Choetetes ._.._....._.-._.__._ 55

Chonetes....--. ....................... 29,30,

33,34,36,37,38,40,41,42,79,80,86,91,92 

Chonetes canadensis t_._..._....._ 84,85

Chonetes complanatus ...... ........ 85

Chonetes cornuta ............_........ 84

Chonetes lata ..._................... 63

Chonetesmelonica .......... J...i.._..._ 84

Chonetes nova-scotica .................. 84,85

Chonetes striatella...........__.... 84

Chonophyllum........................... 35

Chonostrophia. ................... 42

Cladopora .............................. 36,48,55

Clark, J. B., and Schuchert, Charles, 

cited on Devonian aspect of 

Lower Helderberg fauna....... 81

Clarke, J. M., fossils identified by...... 42-43

Clastic rocks, classification of.'.... __ 118-119

descriptions of..... ............... 119-145

Clear Creek, Illinois, fossils from....... 43

Cleidophorus............................ 86

Clidophorus .._................ ....... 41

Clonopora ........_..............'...... 43

Cobscook Bay series, fossils from ...*.. 34
INDEX. 207

Pago. 

Coelospira... ......................... 36,43

Coenostrorna.... ....................... 35,3C

Coleolus....... . 1. ... . . 42,46

Coleolut, tenuiciiictum ........ ....... 46

Coleoprion....-..-.-.---- -.-....... 41

Conchidiuin................ ... .... 54

Conglomerates, occurrence and character of.......... . 131-132,133,134-137

plates showing ...... .. ...... 134,144

volcanic, occurrence and character

of......----.-...--.-.----.- ---. 126-131

Conostrophia.....-.-- --.............. 89,90

Conularia............................ 42

Corals.... -.. .......... 38,47,48,50,51,53,54

Cordania. .- ....-. ......------ 42

Cornulites........ -.................. 29,36,41

Crania-.......-."... .................. 40,41,42

Crinoidea................................ 41

Crinoids ................. 31,32,33,36,37,51,55,91

Cryptonella... .............- -. - 43,55

Cucullella ovata..................... 83

Cyrtolites................................ 36,42

Cytoceras...----..-....---.-----.-..-. 36

Cyrtodonta.......................... 29,30

Cyrtia................................... 50,54

Cyrtina.............................. 36,40,42,43

Cypricardinia................. 36,40,42,53,56,86

Cypricardinialamellosa ................ 51

Cyphaspis--. -.. -----.- --- - 42

Cyclorhina.............--..-...--.--..--- 57

Cyclopteris ....... .................... 31

Cyathophyllum ......................... 36

Cyathophylloid coral. ................ 38

Cypricardella............................ 79,86

D.

Dadoxylon............................... 31

Dalmania................................ 41,53

Dalnmnites.. 30,32,33,34,36,42,43,44,53,54,90,91 

DavisPoint, fossils from................ 28

Dawson, J. William, cited on fossils of

the Arisaig section .............. 84

Debec Jiinction, New Brunswick, localities examined near.............: 203

Deeks, William, cited on fossils of St.

Helens Island, Canada .......... 37,38

Dents Point, fossils from................ 34-35.

Dennysville, fossils from................ 35

Devonian formations, order of ......... 21

Devonian-Silurian boundary in America................................ 25-26

Diabase, analyses of................. 176,179,188

occurrence and character of. 114-116,175-179 

Diaphorostoma........i.................. 42

Dictyonema.. ........................ 40

Dike rocks from granite areas....-.... 149-151

Dikes, Drews Lake...................... 107

Diphophyllum........................... 53

Discina................................ 29,35,41,89

Dodge, W. W., and Beecher, C. E., cited 

on Silurian fossils from PenobscotBay.......................... 35

Downtonian fauna of Wales, American

equivalent of.................... 80

Drews Lake ^granite at......... 106-107,148-149

localities examined at. 194

Page. 

Drews Lake, metamorphism at......... 152

petrography of granite from....... 148-149

Drift bowlders, fossils from ............ 48

Dudley's farm, Castle Hill, near Mappleton Village, fossils from..... 52,53,54

E.

Eakins, L. G., analysis by............... 155-156

Easton Center, localities examined near 194 

Eatonia............... 32,37,39,40,43,54,55,57,60

Eatoniamedialis ...........__...... 57

Ediocrinus............................... 43

Edmunds Hill, andesites at............. 112

augite-andesite at................... 169-172

fossilsfrom.......................... 79

localities examined at............... 196

plate showing cleaved andesite

from ............................. 101

Encrinurus.............................. 36

Endoceras proteiformo ................. 46

Eucalyptocrinus ........................ 36

P.

Fairbanks, H. W., analysis by.......... 183-184

Fairmotint Station, localities examined

near.............................. 194

Favosites.......... 29,31,32,35,36,37,38,48,53,55

Favositesgothlandica................... 52

Fenestella ........................ 32,36,37,38,43

Pistulipora............................... 43

Plorenceville, New Brunswick, localities examined near.................. 203

Port Fairfleld, localities examined near. ] 94 

Frenchville, sandstone at...... _..... 133

Freck, Fritz, cited on Devonian age of

the Hercynian...?............... 81

Fucoides........................ ........ 30

G.

Gardner Creek, localities examined on. 201 

Gaspe limestone, age of...........'...... 23,26

Gaspe series of Canada, fossils from.... 39-41

geologic place of transition from

limestones to sandstones in..... 87

Gaspe sandstones, age of................. 23

horizon equivalent to ............... 80

Geikie, A., cited on spheroidal or sackshaped structure of basic lavas. 174 

Genth, F. A., analysis by............... 155-156

Oilman's farm, Ashland, fossils from .. 52,53 

Glyptodesma...................._.... 79

Goinphoceras....... ........ ....... 36

Goniophora.......................... 40,41,42,86

Grand Falls, New Brunswick, localities examined on................ 203

Grammysia.. ........................ 40

Granite-porphyry, occurrence and

character of ...................... 150-151

Granites, metamorphism by...._.... 151-152

occurrence and character of........ 105-107

petrography of...................... 146-152

Graptolite shales, age of............... 21,22,46

features and fossils of............... 45-46

Graptoli thus............................. 46

Greenlow Brook, localities examined

on................................ 203
208 INDEX.

Page.

Gregory, H. E., collection of fossils by.. 14 

fossils collected by ..._..._.__ 45 

paper on geology of Aroostook volcanicarea by _..._...._.... 93-188

H.

Hall, James, cited on Beyrichia pustulosa......-............ _.._.--.' 85

cited on features of Chonetes nova

scotica .._.. ...._........ 85

fossils described by ............. 41

Hall and Clarke, cited on characters of

the "Bhy nchonellidse.. ....... 57

cited on omission of Camarotcechia

from Lower Helder berg faunas. 59 

cited on Rhynchonella......._. 58

Halycites ................................ 36

Hawes, G. W., analyses by.............. 176-177

Haystack Mountain, diagram of.... 109

features of........................... 107-108

localities examined at and near .... 200,201

plate showing spherulitic rhyolite

and vesicular lava from...... _ 107

rhyolites at.......................... 152-161_

vesicular lava at............_...... 159-161

view of............................... 107

volcanic tuff near................._ 121

Haystack rhyolite, occurrence and

character of ..................... 107-109

Hederella............:................... 43

^Hedgehog Mountain, localities examined at ........................... 199

trachyte at...................... 110,161-162

Heliolites............................... 35,36,37

Heliopora................................ 41

Hemitrypa........................... 43

Horseshoe Pond, fossil from............ 29

Hillebrand, W. P., analyses by .......... 124,

138-139,155,166,171,176,178-179,183,188 

Hindia................................... 43

Hitchcock, C. H., cited on age of Aroostook limestones ............... 141

cited on age of fossils from Aroostook County, Maine............. 44

cited on age of Mapleton sandstones. 137 

cited on granite area at Drews

Lake............................. 106

cited on localities of Oriskany

(Moose Eiver) sandstone........ 88

cited on Paleozoic fossils of Maine. 27,

28,29,30,31 

cited on rocks of Mars Hill ......... 134-135

fossils identified by ...._... _.... 30

geological map and description prepared by......................... 103-104

quoted on features and age of limestone at Ashland................ 52

surveys by........................... 103-104

Hipparionyx.- ......__.............. 42

Hobart Hill, andesites at _............ 113

hornblende-andesite at............. 172-173

localities examined at............... 196

plate showing cleaved andesite

from ............................. 101

Hodge, J. T., cited on occurrence of

Lower Helderberg rocks------ 31

cited on rocks at Mars Hill......... 134

Hodge, J. T., surveys by................ 102

Holmes, Ezekiel, surveys by... ...... 103

Holopea................................. 34,79,86

Holopella (Turritella) obsoleta......... 83

Homalonotus..................... 29,36,41,42,79

HomalonotusKnightii .................. 87

Honeyman, D., cited on age of rocks of

Arasaig section.................. 40

Hornblende-andesite, occurrence and

character of.........-......... 172-173

Houlton Station, localities examined

near.............................. 193

Hudson River series, age of ............ 23

Hunter, M., analyses by ................ 183-184

Hyatella ................................. 53

Hyolithes................................ 36

Hypothyris.............................. 57,60

I.

Ichthyocrinus ........!............__ 36

Igneous rocks, occurrence and character of............................. 105-117

petrography of...................... 146-186

Illsenus................................... 36

Illinois, fossils from..................... 43-44

Iron slate, manganiferous, plate showing ............................... 144

Ivys Corner, New Brunswick, localities

examined near..._............ 203

J.

Jackman farm, Jackman, fossils from.. 90

Jackson, C. T., cited on hematite beds

on the Aroostook River......... 145

surveys by........................... 102-103

Johnsons Brook, New Sweden, sandstones on.._.......___...... 137-138

Jonesboro, 111., fossils from..... ..... 43-44

K.

Kayser, E., cited on equivalence of 

Lower Helderberg and Hercynian faunas........................ 81

Kemp, J. F., analysis by................. 166

Kersantite, occurrence and character

of................................ 151

Kuch, R.,analyses by ................... 171-172

L.

L'Anse a la Veille limestone, age of.... 23

Lake Telos, fossils from................ 30,33

Lapilli of volcanic tuffs, petrographic

features of....................... 122-123

Lava, andesitic, plate showing ......... 112

vesicular, plates showing........... 107,160

Leiopteria ............1.................. 79

Leiorhynchus............................ 39,57

Leperditia.. ..................... 33,36,41,42

Lepidodendron.......................... 31

Lepidostrobus. .........*................ 31

Leptsena.. 29,36,37,42,43,47,48,49,50,53,54,55,86 

Leptsenalata........................... 83,84,85

Leptasna transversalis...... _........ 49

Leptagonia .............................. 38

Leptocoelia..................30,32,34,37,40,43,89

Leptodomus.-......... ..........1.^.. 30,33,40

Leptophloeum ........ .......... 31
INDEX. 209

Leptocoelia............................... 90,91

Leptostrophia .. ....... ..._ ._,... 42

Lichas................................ 32,33,53,56

Limestones, occurrence and character

of....................... -. .. 139-143

plates showing._._. _............ 140,142

Lingula............ 28,34,a5,36,37,40,41,42,86,91

Lissopleura.............................. 89,90

Little Brassua Lake, fossils from....... 91

Littlefield's farm, Chapman, fossils

from ... ....................... 54

Lituites-.....-................---- .... 41

Localities examined, list of. ......... 189-203

Logan, William, quoted on Paleozoic

rocks of Canada ................ 22,23,24

quoted on Silurian and Devonian

rocks of Canada ................ 22,23,24

Long Pond, fossils from................. 90

Lower Helderberg, Canadian equivalents of....................... 26,26-27,27

Loxonema............... 33,34,36,79,86,89,90,91

Lubec lead mines, Maine, fossils from.. 28 

Ludlow, aplite at........................ 149

granite quarry at.......... ......* 107

granite- porphyry near.............. 150

localities examined near ........ 196

metamorphismnear.._........... 152

petrography of granite from quarry

at................................. 148-149

Ludlow Station, localities examined

near.............................. 194

Lyriocrinus....... ............ 55

M.

McDonalds Hill, localities examined at. 200 

Machiaspor t, Silurian fossils from...... 28

Madawaska Lake, localities examined

atandnear ...................... 199,200

plate showing sandstone from... 134 

volcanic conglomerates at.......... 128,131

Madawaska Eiver, localities examined

on ............ ..-.............. 195

. volcanic conglomerates on branches

of................................. 127-128

Magruder, E. W., and Jones, W. A.,

analyses by.............. 155-156,171-172

Mahan, E. W., analysis by....... .... 155

Manganiferous iron slates, occurrence

and character of.. ... .. 145 

plate showing........................ 144

Map, Aroostook volcanic area......._ 105

showin g areas examined .. _.. _ 12 

Mapleton, localities examined at and

near.......................... 196,197,200

Mapleton conglomerate, plate showing. 144 

Mapleton granite, occurrence and character of .......................... 105-106

petrography of...................... 146-148

Mapleton sandstone, age of............ 21,22,88

fossils of ............................. 88

occurrence and character of........ 136-137

Mapleton Township, andesites in....... 113

geologic map of part of ..... 116

 metamorphismin .......______ 151-152

granite in............................ 105-106

sandstone in.................._.... 136-137

Bull. 165 14

Mapleton Village, andesites at.......... 173

Maploton-Presque Isle road, section on. 113 

Mars Hill, conglomerate at............. 134-136

diabase at.................... 115-116,177-179

fossils from...................... 48-49,79-80

localities examined at and near. 193-194,203 

section at............................ 135

Masardis,fossils from ................... 33

localities examined at and near .... 201,202

sandstones at........................ 138

Meek and Worthen, fossils identified by 43 

Megalanteris .._.._........___ 90

Megambonia............................ 34,37,42

Megaphyton.. .. . ............ 31

Meduxnekeag Eiver, localities examined on.._.._......._..... 203

Merista .................................. 43

Meristella......................... 33,42,53,55,56

Meristina ........_........._........ 36

Metamorphism caused by granite intrusions.......................... 151-152

Microcline and orthoclase intergrowth,

figures showing . ._._. 149,150 

Missouri, fossils from ......._........ 43

Modiolopsis................. 28,29,30,34, 3T>, 40,41

Modiomorpha ....................... 35,40,90,91

Monograptus............................ 35,46

Monograptuspriodon....... __... 46

Monticello, localities examined near... 194 

Monticello Station, localities examined

near.............................. 194

Monticulipora........................... 36,43

Moose Island, fossils from .............. 35

Moose Eiver sandstone, age of. ...... 21,22

features and fossils of............... 88-92

Moosehead Lake, fossil -from............ 29,30

Munson's granite, occurrence and character of .......................... 105-106

Murchisonia............. 29,30,35,36,40,41,56,86

Murchison, Eoderick, cited on naming

of the Silurian system ...... 82

cited on taxonornic value of Beyrichiapustulosa................. 85-86

cited on upper limit of Silurian

rocks..-..-.-..- ............... 83

Myrianites. ._..__....... 28

Mytilarca ............................. 40,53

N.

86

28

37

203

115

Natica ......._......._......_....

Nereograspus ..........................

New Brunswick, fossils from...... 

localities examined in..... ......

New Limerick, diabase near...........

New Sweden, calciferous quartzitic

sandstones at.................... 138-139

localities examined near .... .... 198,199

manganif er ou siron slates at.... . 145

rocks and fossils at.................. 51

New Sweden Township, fossils from... 48

volcanic conglomerates in .. 127-128,129-130

New York, fossils from................. 42-43

Nickerson Lake, localities examined at. 194 

Nictaux iron ores, age of fossils of. 87 

North Haven series, Penobscot Bay,

fossils of........._............... 35

Nucleospira.......................... 36,53,54,55
210 INDEX.

Pago. 

Nncleospirapisiformis. -....!-.......--- 44

Nucula. ................................. 36,79,90

Nylander, 0. O., aid rendered by....... 14

fossils collected by .............. 14,54,55,78

Olivenbaum farm, New Sweden, rocks

and fossils at..... ............. 51

Oriskany fauna of Becraft Mountain,

New York ......................... 42-43

Oriskany sandstone, European equivalents of... ..-..-.- - .........-. 86

features of fossils of ............. 61, G2, 88-92

horizons equivalent to .............. 80, 82

Odontocephalus .. .. ............. 44

Oncoceras... ............................. 36

Orange Bay, fossils of .................... 34

Orbicula ............... ...^... ... ......... 34

Orbiculoidea _.....".................-..--- 42

Ormoceras . _ _ ........... .............. 41

Orthis. ............ 28,29,30,32,33,34,36,37,38,40,-

41, 42, 43, 44, 47, 48, 50, 51, 52, 53, 55, 86, 91 

Orthis lunata. ........................... 83

Orthoceras -.. ...._....... ...:....-. 28,29,30,

32, 33, 34, 36, 41, 46, 53, 56, 79, 86 

Orthoceras bullatum. ................... 83

Orthoclase and microcllne intergrowth,

figures showing.. _ .. _ ...... 149,150

Orthonota .............................. 35, 41', 79

Or thorhynchula.. ...... ................ 57,59,60

Orthothetes .......... 42,47,49,50,51,53,55,90,92

P. 

Pachypora... ............................ 38

Packard, A. S., surveys by .......... 103

Paleocyclas .............. ............ . 53

Paleodelasma ........................... 48

Paleoneilo... ..---..--.-.,-.------...-.--. 79,86

Paleozoic faunas known from Maine. . . 27-36 

Paleozoic rocks, Canada, classification. 22-24 

Parazyga .................... ...i.. ........ - 55

Parlin Pond, fossils from ........... ... 30, 89-90

Pembroke, fossils from ................. 29

Penobscot Bay, fossils of ................ 35

section at. ......._...... .. ...... (note) 35

Pentamerus .............. 36,37,39,40,48,49,53,54

Pentamer us pseudogaleatus ............ 38

Perham Township, volcanic conglomerates in ..................... 128,130-131

Perlitic rhyolite, features of .....*..... 157-158

plate showing. ...... ................. 158

Perry, fossils from...... ................. 28,31

Petraia.. ........... ...................... 29

Petrographic descriptions, tuffs ....... 122-126

volcanic conglomerates............. 128-131

Phacops...... ............ ...... 33,41,42,53,56

Phacops logani .......................... 51

Phillipsastrea. ...... ............ _ .;.... 40

Pholidops. ............................... 33,42

Phragmoceras ---.....-...--.....---.---- 41

Pirsson, L. V., analyses by.... ------ 155-156, 166

petrographicwork by.---.----- --- 11

Plagioclase crystal, diagram showing

optical measurements of ........ 182

Platyceras......... 32,33,34,42,43,50,53,56,90,92

Platyostoma...... .... 29,30,31,33,34,36,38,39,47

Page. 

Plethorhyncha.......................... 60

Pleurodictyum.......................... 44,79

Pleurotomaria ....... 28,29,35,36,40,41,42,48,86

Pocomoonshine Creek, localities examined on............................ 203

Polydelasma turbinatum............... 53

Polypora............................. 37,38,40,43

Port Daniel sandstone, age of........... 23

Pratt, J. H., analysis by ................ 176-177

Presquelsle, fossils from............30,44,79-80

localities examined at and near. 195,196,197 

Presque Isle Brook, fossils from _.... 78-79 

Presque Isle River, sandstone on....... 133-134

trachyte on.......................... Ill

localities examined on and near. 196,197 

Presque Isle Station, arenaceous limestones near ..........:......._ 140

Presque Isle-Ashland road, volcanic tuff

on................................ 121

Presque Isle-Mapleton road, section on. 113 

Productus ............................... 44

Proetus............... 31,32,33,36,40,41,42,53,56

Psilophyton......._...................,. 31,79,89

Psilophytonprinceps .................. 87,88

Pterinea ...................._... 33,37,39,41,79,86

Ptilodictya.............................. 37,38,40

Pugnax.................................. 57

Pullastra................................. 86

Pyles Hill, localities examined at..._ 201

rocks of.............................. 109

Q.

Quartz-trachytes, analyses of ...... 166-167,188

occurrence and character of.... 111,164-168

Quebec formation,age of ............... 23

Quoggy Joe. Mountain, localities examined at.................T...... 195

quartz-trachyte at.............. Ill, 164-168

R. 

Reptaria................................. 43

Rensselffiria ................ 30,33,34,40,43,79,80

Rensselseria ovoides, horizon of ..... 24

Retzia..i................................ 29,32,33

Rhynchonella........... 29,30,31,32,33,34,36,37,

.39,40,41,43,53,55,57,58,67,86 

Rhynchonella abrupta.. 64,68,69,70,71,72,73,77 

Rhynchonella acutiplicata ......... 75

Rhynchonella altiplicata. ............ 69,75

Rhynchonella aspasia......... 58,59,69,75,76,77

Rhynchonella barrandi................. 74

Rhynchonella bialveata.... _...... _ 75,77

Rhynchonella campbellana............. 71,73

Rhynch'onellafitchana ............... 74

Rhynchonella formosa.............. 38,58,75,76

Rhynchouella inutilis._............... 76

Rhynchonella loxia..._._............. 61

Rhynchonella mainensis..----. ...... 64,

66.67-68,69,70,77,80 

Rhynchonella multistriata........... 74

Rhynchonella mutabilis. 66,69,70,71,72,73,74,77 

Rhynchonella nobilis................... 71,73,77

Rhynchonella nucleolata...... ...... 38,

66.68-69,71,72,73,77 

Rhynchonella nucula...... .......... 83
INDEX. 211

Rhynchonella oblata..... _ 

Rhynchonella planoconvexa. 

Rhynchonella pliopleur a..... 

Rhynchonella principalis.

Page. 

..... 74

..... 76

..... 74

..... -74

Rhynchonellapyramidata....... 66,70,71,72,73

Rhynchonella ramsayi...... ...... 74

Rhynchonella rudis----------- ' 75,76

Rhynchonella semiplicata ....... .. 75,76

Rhynchonella speciosa.............. 71,72,73,74

Rhynchonellasuessana .... 80 

Rhynchonella sulciplicata .. .. 75,76 

Rhynchonella sulcoplicata.............. 76

Rhynchonella transversa............... 75,76

Rhynchonella vellicata ------- 64,69,70,71,72,73

Rhynchonella ventricosa ........... 71,72,73,77

Rhynchonellas, Square Lake fauna, descriptions of... - ...... 56-78

list of species of.........-.......-.-- 67

plates showing figures of ............ 64,66

Rh ynchonellidte, geologic horizons of.. 57-59 

Rhynchopora.............-."........... 57

Rhynchospira .......................... 32,53,55

Rhynchotrema......................... 57,58,60

Rhynchotrema capax ........ ....... 58

Rhynchotremaformosa ................ 58

Rhynchotrema insequivalve............ 58

Rhynchotreta ....................... 57,58,59,60

Rhyolite breccia, occurrence and character of .........-...-.----.-----. 158

Rhyolites, analyses of............... 155-156,188

occurrence and character of. 107-109,152-161 

perlitictypeof............ --- - 157-158

plate showing " birch-bark " weatheringof.................. ...... 108

plate showing perlitic type of ...... 158

spherulitic, from Haystack Mountain, plate showing.............. 107

Ripogenus Falls, Lower Helderberg,

rocks at.................. .... 31

Rogers, W. B., fossils identified by..... 29

Rohrig, A., analysis by ..... ....... 171-172

Romingeria...... ... ... ... 43

S.

St. Croix River, localities examined on.. 199 

sandstones on........................ 144

St. Croix Station, slates and sandstones

at and near .................._ 144

St. Helens Island, Canada, fossils from. 37-39

St. John River, localities examined on. 203

Salmon Brook, localities examined on . 197

volcanic conglomerates on...... 128,130-131

Salter, J. W., cited on age of fauna of 

rocks of Arisaig section, Nova 

Scotia.......................!.... 41

Sandstones, analyses of. _............ 139,188

occurrence and character of. 131-134,136-139 

plates showing ...................... 132,134

Sanguinolites............................ 40,79

Schists and slates, occurrence and character of .......................... 143-145

Schizocrania.____..__...... 36

Schmelck, analyses by .............. 166,176-177

Schneider, E. A., analyses by........... 183-184

Page.

Schuchert, Charles, cited on genera of 

 > the Rhynchonellidee............. 57

Schuchert, Charles, and Clark, J. B., 

cited on Devonian aspect of 

Lower Helderberg fauna ....... 81

Seboois River, fossils from.............. 29,30

Sedgwick Lake, features and fossils of

limestone at...... _. _.. ___ 54-78

See also Square Lake. 

Serpulites-...-............_...._.... 41

Shaler, N. S., cited on Silurian deposits

of Cobscook Bay................. 34

Sheridan Plantation, fossils from _... 47

Sheridan sandstone, age of .. _.. _ 21,49,51

features and fossils of...........__ 47-49

occurrence and character of _ _. 132-133 

plates showing .........._____ 132,134

Sillery rocks, age of..................... 23

Silurian system, passage beds from_ 83 

upper limit of..........__._... 83

formations of........................ 21

Silurian-Devonian boundary In America................................ 25-26

Slate, plate showing..................... 144

Slates and schists, occurrence and character of .......................... 143-145

Smyrna Mills, localities examined near. 196

slates and sandstones at and near.. 144 

Somerset County,' new Paleozoic fossils from ......................... 44-92

South Mapleton, andesites in._.._ 113 

Sphenopteris ................. ...1_... 31

Sphenotus .........................._.. 91

Spherulitic rh'yolite, plate showing.... 107

Spirifer ........... 34,35,36,37,38,41,42,43,44,47,

48,49,50,51,53,54,55,79,80,86,89,90,01,92 

Spirifer arenosus.. .............._ 61

Spirifer concinnus ..................._ 38

Spirifer cyclopterus._..__.__ 38,80 

Spirifer elevatus ...........__._.... 83

Spirifer hesione".......................... 32

Spirif era..... 28,29,30,31,32,33,37,38,39,40,52,80

Spirorbis........ .................._ 42

Spragueville, arenaceous limestones

near_.......................... 140

localities examined at............... 195

Square Lake, age of fauna of.... 21,22,26,51,56

features and fossils of limestone at. 30, 

31-33,54-78

plates showing Rhynchonellas of

limestone at..................... 64,66

Square Lake fauna, Canadian equivalents of........................... 87

Square Lake limestone, age of... 21,22,26,51,56

features and fossils of........ 30,31-33,54-78

Rhynchonellas of.................... 64,66

Square Mountain, fossil .from ...._... 29

Lower Helderberg rocks at. _. _ 31 

Stenopora .............................. 29,37,41

Sternbergia.............................. 31

Stictopora ............................... 36

Stokes, H. N., analysis by ...A......... 171-172

Stony Brook, fossils from. ........... 91

Streptelasma _ ..............._.. 35,48

Streptorhynchus................. 30,32,33,36,38

Striatopora............. ...... 43
212 INDEX.

Stricklandinia....-. .................. 38,43

Stromatopora :.....- ... .... 55.

Stropheodonta ....... 36,42,47,48,50,51,53,54,89

Strophodonta-....-'-.-.----------..-- 34,37,38,55

Strophodonta punctulifera............. 38

Strophodonta-varistriata.. .......... 38

Strophomena.. .. 29, 30,31,32,33,36,37,38,40,

43,44,47,48,49,50,51,52,53,54,55,90, 91, 92

Strophomena c'avumbona...... ...... 32

Strophomena fragilis Hall.............. 32

Strophomena crenistriata . ------- 32

Strophomena headleyana. .... 32 

Strophomena perplana Con............. 32

Strophomena planulata................. 32

Strophomena pluristriata Con.......... 32

Strophomena punctulif era Con 32 

Strophonella._.-.-- .................. 38,42,55

Strophostylus...... ................ 42,43,53,56

Surveys of Maine, account of . . 102-104 

Syenite, occurrence and character of.- 149-150 

Syringopora..... ..... 35,36

T.

Teeds Mill, New Brunswick, localities

examined near............... 203

Tellinomya ................... 36

Telos Lake,fossils from................. 30,33

Tentaculites................ 29,36,41,42,79,86,90

Terebratula ......... ............. 86

Terebratula nucula . .... 83

Terebratula strigiceps ........... 80

Terebratuloides.................... - 57

Teschenites, analysis of............. _. 183,188

occurrence and character of. 116-117,179-186 

Theca---............-..... -........ 41

Tilestone of England, American equivalent of........................ 80-81,82,84

fauna of.......................... 83,85,86-87

Topley's, New Brunswick, localities examined near ..... ............. 203

Trachypora........... ................ 43

Trachytes, analyses of.............. 163,166-167

occurrence and character of. 109-111,161-168 

Trematospira ........... 32,34,39,42,43,48,53,55

Trenton limestone, age of .............. 23

Trochus..-........-- -------.-.---- - 86

 Trochushelicites--------- ........ 83

Tschermak, analysis by................. 183-184

Tuffs, volcanic, analyses of............. 134,188

occurrence and character of........ 119-126

petrographic descriptions of ....... 122-126

plate showing ................... . 160

Turbo..... ............................ 86

Turrilepas........... . ..... . 42

Turritella....... ....-.- .......... 86

U.

Uncinulus ..................... 57,58,59,60,61,62

Uncinuliisstricklandi........... . 58

Upper Salmon Brook, localities examined on and near...... .. 201

Utica shale, age of . .......... 23

12,14 

88-92

87

159-161 

107,160

37

42

128-131

126-131 

124,188 

119-126 

122-126 

160

V.

Van Ingen, Gilbert, collection of fossils 

by........................... ....

fossils collected by........_.......

Verneuil, P. E. P. de, cited- on place of

Silurian-Devonian boundary in

 North America..................

Vesicular lava, occurrence and character of.............................

plates showing ......_............

Victoria County, New Brunswick, fossils from ...._____..........

Vitulina..................................

Volcanic conglomerates, petrographic 

descriptions of...... . ........

Volcanic sandstones and conglomerates, 

occurrence and character of....

Volcanic tuff,analyses of .._._.....

occurrence and character of........

petrographic descriptions of .......

plate showing.......___......

W.

Wade, localities examined near _..... 201

Warren, C. H., analysis by.............. 163

Washburn, localities examined near... 198,201 

Washburn Ferry, metamorphism of

rocks near........................ 151

Washburn Township, localities examine.din ........................... 197,198

Washington, H. S., analysis by......... 183-184

Waterville, fossils from................. 28

Webster Lake, fossils from......... _. 30

Weeksboro, slatesat_................ 144

Weeksboro Station, diabase near ...... 115

localities examined near ............ 196

Welts Brook, localities examined on and

near.............................. 200,201

rhyolite on ..... .............. 109

volcanic conglomerate on...._ 127,128-129

Whitfleld, J. E., analysis by ............ 171-172

Whiting Bay, fossils of.................. 34

Williams, H. S., collection of fossils by. 14

letter of transmittal by.... ...... 9

list of localities by.................... 189-203

paper on Paleozoic faunas by....... 15-92

preface by .... ................ 11-14

Wilsonia ............................. 57,58,60,62

Winslow's farm, near Ashland, features

of rocks at. ............. 50

fossils from......................... 51,52,53

Winslow's Hill, section at............... 136-137

Woodland, fossils from.................. 48

manganif erous iron slates at....... 145

Woodland Township, localities examined in............................ 198

trachytic rock from................. 164

Woodstock, New Brunswick, localities

examined near... ............ 203

Z.

Zaphrentis......... 31,32,37,38,40,43,44,52,55,91

Zygospira....... ... 43

o