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BULLETIN

OF THE

GEOLOGICAL SOCIET\

7

OF

AMERICA

VOL. 4

JOSEPH STANLEY-BROWN, Editor

LfBRART
NEW YORK
^CiC/^x BOTANICAL

ROCHESTER

Published by the Society

lso:;

col MIL FOR 1893

Sir J. William Dawson, President

T. C. Chamberlin, \

Vice-Presidents
.1. .1. Stevenson, )

II. L. Fairchild, >'<<•/■< /''/•//

I. ('. White, Treasurer

Class of 1895

E. A. Smith,

C. D. Walcott,

Class of 1894

Henry S. Williams,

X. II. WlNCHELL,

Class of 1893
George M. Dawson,
John C. Branner,

• Members-at-la

PRINT]
JUDD >V DETWEILER, WASHINGTON, I1 '

NGRAVERS

Moss Engraving Co., Puck Building, New York

(ii)

c:>

CONTENTS

Page
Proceedings of the Fourth Summer Meeting, held at Rochester, August 15 and

L6, L892 ; 1 1. L. Fairchild, Secretary 1

Session of Monday, August L5 1

Election of Fellows 1

Studies of the Connecticut Valley Glacier ; by C. 11. Hitchcock..-.. :;

Session of Tuesday Morning, August 16 , 8

The Oneonta Sandstone and its Relations to the Portage, Chemung

and Catskill Groups (discussion) ; by James Hall 8

Session of Tuesday Afternoon, August 16 9

Conditions of Accumulation of Drumlins (discussion); by Warren

UlMIAM \)

Ancient Waterways (abstract) ; by A. S. Tiffany 10

Register of the Rochester Meeting 12

Finite homogeneous Strain, Flow and Rupture of Rocks ; by G. F. Becker... 13
The Thickness of the Devonian and Silurian Rucks of central New York ; by

C S. Prosser ill

A new Tseniopteroid Fern and its Allies ; by David "White 119*

Some Elements of land Sculpture ; by L. E. Hicks 133

Some dynamic and metasomatic Phenomena in a metamorphic Conglomerate

in the < rreen Mountains; by C. L. Whittle 147

Phases in the Metamorphism of the Schists of southern Berkshire; by W.

II. Hobbs U>7

Continental Prohlems; Animal Address by the President, G. K. Gilbert 171)

Comparison of Pleistocene and present Ice-sheets ; by Warren Upham 191

Cretaceous and early Tertiary of northern California and Oregon; by J. S.

DlLLER 207)

On the Geology of natural Gas and Petroleum in southwestern Ontario; by

H. P. H. Brumell 225

Notes on the Occurrence of Petroleum in Gaspe, Quebec ; by IT. P. II. Brumell. 241

The Faunas of the Shasta and Chico Formations ; by T. W. Stanton 245

Two Neocene Rivers of California; by Waldemar Lindgren 257

Some Maryland Granites and their ( >rigin ; by C. R. Keyes 299

Epidote as a primary Component of eruptive Rocks ; by C. R. Keyes 305

Relations of the Laurentian and Huronian Rocks north of Lake Huron; by

A. E. Barlow 313

The Archean Rocks west of Lake Superior ; by W. 11. ( '. Smith 333

The Laurentian of the Ottawa District ; by R. W. Ells 349

Height of the Bay of Fundy Coast in Hie Glacial Period relative to Sea-level,
as evidenced by marine Fossils in the Bowlder-clay at Saint John, New

Brunswick ; by Robert Chalmers 361

Proceedings of the Fifth Annual Meeting, held at Ottawa, Canada, December

28, 29 and 30, 1892 ; H. L. Fairchild, S< m tary 371

Session of Wednesday, December 28 372

Report of the Council 372

*-*» (iii)

°*

IV BULL. GEOL. SOC. AM., VOL. 4.

Page

Reporl of the Treasurer 376

Election of Officers for 1893 378

Election of Fellows 378

Memorial of Thomas Sterry Hunt (with bibliography) ; by Raphael

Pi mpelly 379

Memorial of John Strong Newberry (with bibliography) ; by J. F.

Kemp 393

Memorial of James Henry Chapin (with bibliography); by \V. M.

Davis 406

< in the < reology of natural Gas and Petroleum in southwestern On-
tario (discussion by I. C. White and II. M. Ami); by II. P. II.

Brumeli 408

Note on fossil Sponges from the Quebec Group (Lower Cambro-
Silurian) at Little Metis, Canada (abstract); by J. Wm. Dawson. 409

Evening Sessii >n of Wednesday, December 28 411

A fossil Earthquake (abstract) ; by W J McGee 41 1

Session of Thursday, December 29 415

Third Annual Report of the Committee on Photographs 415

Notes on the glacial Geology of western Labrador and northern

Quebec ; by A. P. Low 419

The supposed post-glacial Outlet of the Great Lakes through Lake

Nipissing and the Mattawa River; by G. Frederick Wright. . . . 4'S.j
Notes on the Geology of Middleton Island, Alaska; by George M.

1 >aws< >x 427

Session of Friday, December 30 4-'!2

Evening Session of Friday, December 30 4IJ4

The Huronian Volcanics south of Lake Superior (abstract) ; by

C. R. Van Hise 435

On two Overthrusts in eastern New York ; by N. H. Darton 436

Register of the Ottawa Meeting, 1892 440

List of Officers and Fellows of the Geological Society of America 441

Index to Volume 4 4ol

ILLUSTRATIONS.

Front is] >iec< — Portrait of John Strong Newberry 1

Plate 1— White: New Tseniopteroid Fern (7 figures) . . .' -. . . 119

2 — Whittle: Secondary Enlargement of clastic Tourmaline (2 figures). 156

3 — Hobbs: Sections of garnetiferous porphyritic Schisl (2 figures) 178

4— Diller: Map of northwestern California ami southwestern Oregon 205
5— Lindgren : Recent and Neocene drainage Systems of the Yuba and

American Rivers, Sierra Nevada, California 257

0 ( rradesof the Neocene Yuba and American Rivers, Sierra

Nevada. California L'li:;

7 tions showing Neocene drainage Systems 265

* : ions showing Neocene drainage Systems 266

9 ( rrade Profiles of Neocene and present Rivers 296

10— Keyes: Gneiss Enclusion in Granite— Woodstock. Maryland 299

ILLUSTRATIONS. V

Page

Becker : Figure 1— Scission 24

" " 2 — Range of circular Sections 32

" " 3 — Stresses in finite Shear 36

" " 4— Systems of Forces 41

" " 5— Plastic Solid under Pressure 47

" " 6— Strained Cubes 56

" " 7— Widest possible Spacing of Fissures 57

" " 8 — Spacing <>f Fissures 58

" " 9— Effect of Potation on Fissures 59

" " 10— Results of Rupture by Pressure at 30° to fixed Plane 63

'< " 1 1— Results of Rupture by Pressure at 60° to fixed Plane 63

" " 12— Contraction of Mass cooling from one Side 69

" " 13— Primary tension Cracks 70

" " 14— Secondary tension Cracks 70

" " 15 — Cooling of Columns 71

" " 16— Paul uve's Experiment on Crushing 74

" " 17— Steps in Slate 76

" " IS— Origin of Cleavage in Wire 80

" " 19— Development of Cleavage by Extrusion '. 81

" " 20— Development of Cleavage by direct Pressure 82

" " 21— Effects of Compressibility 85

" " 22— Deflection of Cleavage by Grit 86

Hicks : ' ' 1— Weather Curve '35

" " 2— Water Curve of Erosion 136

" " 3— Combined weather Curve and water Curve 137

" " 4— Unstable artificial Curve 138

<< " 5— Normal relief Form in an advanced Stage of Base-level-

mg 1,j0

. << " 6— Typical Profile of the drainage Slopes of Mountains 138

« " 7 — Cross-profile of bad land Divide • • • 139

" " 8— Illustrating the Coexistence of steep Slopes with broad

weather Curves in an early Stage of Base-leveling 140

" " 9— Miniature Butte in the Bad Lands 142

" 10— Cross-section of a constructive River 143

<: " 11— Cross-section of a river Valley having no Flood-plain . .. 145

" 12— Cross-section of a broad Valley of the Plains having no

Flood-plain 145

Whittle: " 1— Thin Section of Ottrelite-schist 151

2— Thin Section of Ottrelite 152

'< " 3 — Thin Section of water-worn Tourmaline Pebble 157

" " 4— Thin Section of microcline Pebble 100

" " 5— Thin Section of microcline Pebble |(>3

Hobbs: " 1— Examples of Deformation and modified Growths of Min-
eral in Schists 170

" " 2— Secondary Enlargement of Plagioclase '72

" " 3— Garnets with secondary Enlargements 174

" « 4— Portion of a Crown of Staurolite and Magnetite encir-
cling a garnet Individual L75

vi BULL. GEOL. SOC. A.M.. VOL. 4.

Page

Gilbert: Figure I — < Jeneralized Profile, showing relative An -as of tin- Earth's

Surface al differenl Heights and Depths 180

" " 2— The continental Plateau as related to the Western and

Eastern Hemispheres 181

" " :j — The continental Plateau, developed on a plane Surface . . L85

4 — Oceanic Area complementary to the continental Plateau,

developed on a plane Surface 185

5— Area of continental Plateau, developed with reference to

a great ( !ircle 1 V|'.

Keves: " 1 — Microscopic Crystal of Epidote in Ellicott City (Mary-
land) < rranite 309

2— Epidote in Ellicott City Granite 309

" " 3— Epidote in Woodstock (Maryland) Granite 309

" 4— Epidote in Woodstock Granite 309

Darton: " 1 — Cross-section of Ridge on south Side of Rondout Creek,

at Rosendale, Ulster County, New York, looking North. 4:;7
" " 2 — Cross-section of Overthrust west of South Bethlehem,

Albany County, New Y< >rk 438

" " 3— Overthrust on Sprayt Creek. Section on north Bank,

looking North 439

(10 plates, .").") figures.)

PUBLICATIONS OF THE GEOLOGICAL SOCIETY OF AMERICA.

Regular Publications.

The Society issues a single serial publication entitled Bulletin of the Geolog-
ical Society of America. This serial is made up of proceedings and memoirs, the
former embracing the records of meetings, with abstracts and short papers, lists of
Fellows, etc., and the latter embracing the larger papers accepted for publication.
The matter is issued as soon as possible after acceptance, in covered brochures,
which are at once distributed to Fellows and exchanges. The brochures are
arranged for binding in annual volumes, which arc elaborately indexed.

The Bulletin is sold to Fellows and the public either in full volumes or in sepa-
rate brochures. The volume prices are, to Fellows, a variable amount depending
on the cost of publication ; and to libraries and the public, the fixed amounts given
below. The brochure [trices for volumes 1 and 2 are given on pages ix-xi of vol-
ume 2; the prices for the brochures of volume 3 are givon on pages viii-ix of that
volume.

Volume 1, covering the work of the Society from the organization, in 1888, to the
end of L889, comprises 593 | xii pages, L3 plates and 51 cuts. Price to Fellows,
$4.50; to libraries, $5.00; to the public, $10.00.

Volume 2, covering the workt)fthe Society for 1890, comprises 002 -p xiv pages,
2.'] plates and O.'i cuts. Price to Fel lows, $4.50; to libraries, $5.00 ; to the public,
$10.00.

Volume 3, covering the work of the Society for 1891, comprises 541 -f- xii pages,
17 plates and 72 figures. Price to Fellows, $4.00; to libraries, $5.00; to the public,
$10.00.

Volume 4, covering the work of the Society for 1802, is now complete, and com-
prises 458 + xi pages, 10 plates and 55 figures. Price to Fellows, $3.50; to libra-
ries, $5.00; to the public, $10.00. The volume is made up of 10 brochures, as
follows :

Brochure. Pages. Plates. Figures. P,iICB T0 Price to

Proceedings of the Fourth Summer

Meeting, held at Rochester, August

15 and It!, 1892. H. L. Fairchild,

Secretary 1-12

Finite homogeneous Strain, Flow and

Rupture of Rocks. G.F.Becker... 13-90 1-22

The Thickness of the Devonian and

Silurian Rocks of central New York.

C. S. Prosser 91-118

A new Taeniopteroid Fern and its Al-
lies. David White 119-132 0-1

Some Elements of land Sculpture. L.

E. Hicks 133-146 1-12

(vii)

ELLOWS. THE 1'1'lil.lc:

$0.10

$0.20

.70

1.40

.30

.60

.25

.50

.15

.30

Vlll BULL. GEOL. SOC. AM.. VOL. 4.

Brochure. Pages. Plates. Figures.

Peicb to Price to
Fellows, the Public.

o

• >

1-4

.20

.35

1-5

.10

.20

.10

.20

4

.20

.35

15

.30

10

.20

50

1.00

Some dynamic and metasomatic I'he-
oomena in a metamorphic Conglom-
erate in the Green Mountains. C. L.
Whittle 147-166 2 1-5 .25 .50

Phases iu the Metamorphism of the
Schists of southern Berkshire. W.
11. Hobbs 167-178

Continental Problems. G. K.Gilbert. 179-190

Comparison of Pleistocene and presenl
[ce-sheets. W. Upham 191-204

Cretaceous and early Tertiary of north-
ern California and Oregon. J. S.
Dilleb 205-224

On the Geology of natural Gas and
Petroleum in southwestern Ontario;
Notes <>n the ( >ccurrence of Petroleum
in Gasp6, Quebec. II. P. H. Brc-
m ell 225-244

The Faunas of the Shasta and Chico

Formations. T. W. Stanton 245-256

Two Neocene Rivers of California. W.
Lindgren 257-298 5-9

Some Maryland Granites and their
Origin; Epidote as a primary Com-
ponent of eruptive Rocks. C. R.
Keyes 299-312 10 1-4 .20 .:!•">

Relations of the Laurentian and Huro-
nian Rocks north of Lake Huron.
A. E. l',\i:i.o\v 313-332 15 .30

The Archean Rocks west of Lake Supe-

ri« »r. W. II. C. Sm eth 333-348 15 .25

The Laurentian of the Ottawa District.
R. W. Ells 349-360 10 .20

Height of the Bay of Fundy Coast in
the Glacial Period relative to Sea-
level, as evidenced by marine Fossils
in the Bowlder-clay at Saint John,
New Brunswick. Robert Chalmers . 361-370 .10 .15

Proceedings of the Fifth Annual Meet-
ing, held at Ottawa, Canada, Decem-
ber 28, 29 ami 30, 1892 (with frontis- f 371-45S \ ._„ - , ..
piece). H. L. Fairchild, Secretary. \ i-xi j 6 '

[rregulab Publications.

In the interests of exacl bibliography, the Society takes cognizance of all publi-
cations issued either wholly or in pari under its auspices. Each author of a
memoir receives 30 copies without cost, and is authorized to order any additional
number at a slighl advance on cost of paper and presswork; and these separate

brochures are identical with those of the editions issued and distributed by the

Society. Contributors to the Proceedings also are authorized to order any number
of separate copies of their papers at a slight advance on cost of paper and press-
work; hut such separates are bibliographically distinct from the brochures issued
by the Society.

PUBLICATIONS.

IX

The following separates of parts of volume 4 have been issued:

Editions uniform with the Brochures of the Bulletin.

430 eopies. January 3, 1893.
' February 21,

c tt OQ

->,

' ' ' 25

Pages

13- 90,

430

(i

91-118,

180

c<

119-132,

plate

i;

130

it

133-146,

30

a

147-166,

plate

'7 .

— J

55

i i

167-178,

1 1

230

it

179-190,

430

(t

191-204,

30

i t

205-224,

plate

4,

ISO

a

225-244,

130

a

245-251 i,

so

u

257-2'. is,

plates

5-9 ;

130

< i

299-312,

plate

10;

130

a

313-332,

30

i i

no '2 oiu

OKjO—'J-tO,

30

a

349-360,

30

3(31-370,

30

a

27,

a

27,

March

-'4,

April

14,

May

20,

June

8,

t c

19,

July

31,

August

4,

a

4,

t i

7,

if

7,

Pa

Special Editions*

es 379-393, f 30 copies. September

393-406, frontispiece; 30
406-408,
409-410,
411-414,
415-418,
410-421,
423-427,
427-131,
435-136,
436-430,
441-450,
vii-viii,

30

a

30

a

30

u

100

t i

100

a

30

a

200

11

150

a

30

it

100

u

LOO

tt

50

tt

It

it

23
23
23
23
23
23
23
23

< )ctober

18

Without covers.

*Bearing the imprint ["From Bull. Geol. Soc. A.M., Vol. I. 1892."]
■(•Fractional pages are sometimes included.

II— Bull. Geol. Soc. Am., Vol. I, 1892.

CORRECTIONS AND INSERTIONS.

All contributors to volume -1 have been invited to send in corrections and inser-
tions to be made in their contributions, and the volume lias been scanned with
sonic care by the Editor. The following are such corrections and insertions as are

deemed worthy of attention :

it

a

Page 20, in formula for tan X ; for11 a — " reada-\-.

21, first line of foot-note ; " " unchanged length " " unchanged direction,

21, foot-note, 2d equation ; " "y/x — " " yjx=.

27, third formula; " "a = " " — a=.

29, formulas (8) ; " "cos{v — /*) " " <Tcos{v — fi).

36, figure '■'>, letter the triangle in the upper right-hand corner, a b

c

37, formula for T, reverse si^ns of G and Q.

.'!7, line 13 from top; for "page 34" read page 31.

59, last formula ; " "4" "2.

80, foot-note; " "p. 74" "p. 54.

The above are simply misprints, and the correct expressions were em-
ployed by Dr Becker in the deductions and computations.
L85, erase the misplaced "s" to the left of figure 4.
22:;, line 20 from top; for " Wasacht" read Wasatch.

304, " 8 " " " "magnatic" " magnetic.

" 306, " 2 " bottom; " "no. 85" " no. 65.

" 314, " 14 " top; " "Wahnapital" " Wahnapitae.

" 318, lines 15 and 17 from top; " "

" 331, line 5 from top; " " Walter MeOuat" " Walter McQuat.

" 333-348; " " Contchiching " " Coutchiching.

" 340, line 13 from top ; " " Vermiline " " Vermilion.

" 341, lines 14 &20from bottom ; " "RatRoat" " Rat Root.

" 342, line 1 from bottom ; " "no. 9" " no. 1.

" 340-348; " "AticOban" " AticOkan.

:!C>L', line 2(1 from top; after (" true meridian ") omit and.

363, " *i " " omit "obviously."

;;(;:;, " s " " after " Carboniferous " insert systems.

363, " '.) " " omit "systems."

364, " s " bottom ; after " courses " omit of them.

365, " 14 " top; for " Belanus" read Balanus.

366, " 4 " bottom; enclose" Yoldxa arctica of Sars " in parentJiesis.
369, " (> " top; for " has been formed " read has also been formed.
400, " 22 " bottom; " "B.G.Harrington" " B.J.Harrington.
40'.), " 13 " " " " these" " them.
109, " 7 " " " "Sasiothrix" " Lasiothrix.
41(1, " 7 " top; " " hair" " base.
no. " pi " •• after " closely " insert or loosely.

(i

CORRECTIONS AND [NSERTIONS. XI

Page 410, line 16 from top ; after " Palawsaccus" insert *
" 410, " 16 " " for u Palawsaccus" read Palseosaccus.

Also at the bottom of the page insert the following foot-note, to which the star
should refer :

* It has since been described and figured by Dr G. J. Hinde, under the
name Palaseoaceus dawsoni, in the London Geological Magazine, February,
1893, p. 56.
" 410, line 24 from top; for " cusiformis" runt ensiformis.
" 410, " 23 " " " "Astiopollition" " Astropolithon.

Additions to Newberry Bibliography.

Page 400, between lines 12 and 13 from top; insert Remarks on copper Ores in

the Triassic Sandstones of
the United States: Proc.
New York Lye. Nat. Hist. ,
vol. ii?, 1874, pp. 16, 17.

" 401, " " 13 and 14 " bottom; " Remarks on the Genesis of

the Newark Sandstones
contiguous to the Pali-
sades, New Jersey: Proc.
New Yuri: Lye. Nat. Hist.,
vol. i, 1870-1871, pp. 131,
133, 134, 137.

" 402, " " 18 and 10 " " " Remarks on Serpentine of

Staten Island : Trans. New
York Aa id. Sci., vol. i,
1881, pp. 420-422.

" 402, " " 7 and 8 " " " Remarks on the intrusive

Character of the Trap of
Bergen Hill, New Jersey :
Trims. New York Acad.
Sci., vol. ii, 1<SS2-\S3, p.
120.

" 403, " " 22 and 23 " top; " Remarks on the former Ex-

tent of the Newark Sys-
tem : Trans. New York
Acad. Sci., vol. vii, 1887,
p. 39.

" 4()4, " " 7 and 8 " " " Description of new fossil

Pishes from the Trias:
Ann. New York Acad. Sci.,
vol. i, 1879, pp. 127, 128.

" 404, " " 16 and 17 " bottom; " On Dendrophycus triassicus:

American Naturalist, vol.
xxiv, 1 s'.m, pp. 10(58, 1069.

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA
Vol. 4, pp. 1-12 December 27, 1892

PROCEEDINGS OF THE FOURTH SUMMER MEETING, HELD
AT ROCHESTER, AUGUST 15 AND 16. 1892

H. L. Fairghild, Secretary

CONTEXTS

Page

Session of Monday, August 15 ' ]

Election of Follows .,..*. ]

Studies of the Connecticut Valley ( I lacier ; I >y ( !. II. Hitchcock 3

Session of Tuesday Morning, August 1(1 N

The Oneonta Sandstone and its Relations to the Portage, Chemung and

( 'atskill Groups (Discussion) ; by .lames Hall 8

Session of Tuesday Afternoon, August Hi 0

Conditions of Accumulation of I (rumlins (Discussion) ; by Warren TJpham. 0

Ancient Waterways (Abstract) ; by A. S. Tiffany K)

Register of the Rochester Meeting 12

Session of Monday, August 15

The Society met at 2.30 o'clock p m, in the geological lecture-room,
Sibley Hall, University of Rochester; the President in the chair, and
about twenty-five members present.

The President, Mr G. K. Gilbert, opened the meeting with appropriate
introductorv remarks.

ELECTION OF FELLOWS

The Secretary announced as the result of the balloting for the election
of Fellows that the following persons were elected Fellows of the Society :

Alfred E. Barlow, B A, M A, Geological Survey, Ottawa, Out, Field Geologist ;

now engaged in strati graphical geology and working on the Arehean rocks

north of lake Huron.
Henry Phareth Hawdon Brumell, Geological Survey, Ottawa, Out. Assistant,

Division Mineral Statistics and Mines; now engaged in mining geology and

geology of natural gas and oil.

I— Bull. Geol. Soc Am, Vol. 4, 1892. (I)

A PROCEEDINGS OF ROCHESTER MEETING.

Mabius Robisox Campbell, U. S. Geological Survey, Washington, D. C. Geologist ;
now engaged in stratigraphy and structure of the Paleozoic rocks of the Appa-
lachian province.

A.ntonio del Castillo, School of Engineers, City of Mexico. Engineer of Mines
and Director of National School of Engineers. Director of the Geological
Commission for the preparation of the Geological Map of the Republic of
Mexico.

Harold W. Fairbanks, B S, San Diego, Cal. Geologist on staff of State Mining
Bureau; now engaged in general Held geology.

Leox S. Gkiswold, A B (Harvard, 1889), 238 Boston St, Dorchester. Mass. Geolo-
gist : engaged in field work on Triassic area of Connecticut.

Albert P. Low, B of Sc, Ottawa, (Jut. Field Geologist Geological Survey Depart-
ment ; now engaged in the study of the Archean.

Vernon Feee.max Marsters, A B, Bloomington, Ind. Associate Professor of
Geology in Indiana State University ; now engaged in the study of general
geology and petrography.

Albert C. Peale, M D, Washington, D. C. Geologist United States Geological
Survey ; engaged in structural geology and stratigraphy of northeastern Rocky
Mountain region.

William B. Scott, M A, Ph D (Heidelberg), Princeton, X. J. Professor, College
of New Jersey ; now engaged in study of vertebrate paleontology.

Charles Henry Smyth, Junior, A B, Ph B, Ph D, Clinton, X. Y. Professor of
Geology in Hamilton College ; now engaged in the study of the geology of the
western Adirondack region.

Joseph Staxley-Browx, Washington, D. C. Assistant Geologist United States
Geological Survey ; now engaged in the study of petrography and structural
geolog3' in northwestern United States.

Charles Livy Whittle, West Medford, Mass. Assistant Geologist United States
Geological Survey; now engaged in field work in the Archean rocks of south-
ern Vermont.

The President announced that the Council had determined that other
sessions of this meeting should be held on Tuesday, August 16, at 10 .
o'clock a m and at 2 o'clock p m.

No further business being offered, the President declared the scientific
work of the meeting in order, and announced^ the first paper on the
printed program, which, in the absence of the author, was read by W J
McGee :

NOTES ON THE PHOSPHATE FIELDS OF EASTERN MARION AND ALACHUA

COUNTIES, FLORIDA

BY LAWRENCE C. JOHNSON

The paper was discussed by Charles H. Hitchcock. E. \\ . Claypole,
R. A. V. Penrose, Junior, 1. C. White and W -I McGee.

C. H. HITCHCOCK THE CONNECTICUT VALLEY GLACIER. 3

The second paper presented was —

ON THE DENTITION OF TITANICHTHYS AND ITS ALLIES
BY E. W. CLAYPOLE

it

On behalf of the Committee on Photographs Mr C. W. Hayes an-
nounced that the photographs recently acquired were displayed in the
adjoining hall of the University Geological Museum.

The following paper was then read :

STUDIES OF THE CONNECTICUT VALLEY GLACIER
BY C. II. HITCHCOCK

Reference may be made firs! to the literature of the subject by Professor E. Hitch-
cock, who believed the Lee marks in general were produced by icebergs, and recog-
nized true glacial phenomena in the AVestfield and Deerfield river valleys tributary
to the Connecticut. This was in 1853. Ten years later Professor J. D. Dana com-
mented upon these and related farts, and presented the view that the markings
were not produced by Local glaciers, but were made by the general ice sheet, the
variation in direction having been due to pressure. Professor Louis Agassiz, in
1872, recognized local glaciers entirely subsequent to and independent of the main
ice sheet in a part of the White mountains. The present author has also recorded
similar views in various papers and reports. .

A more thorough examination of the main Connecticut valley in the vicinity of
Hanover, New Hampshire, has recently been made in order to afford a better under-
standing of the facts. Over a territory thirty miles long and from ten to fifteen
miles wide nearly every 1 dge has been scrutinized, and the directions of stria? re-
corded. The record includes two bundled observations within this area. The
attempt was made to have this record exhaustive, and to include the markings
on both sides of the valley movement. The general conclusion is that two move-
ments are indicated: first, in the direction S. 30° E., principally on the highland
borders; secondly, in the direction S. 10° W., existing only in the depressed area.
More specific conclusions are the following:

1. In addition to the Connecticut valley movement in the direction indicated by
the topography, there were numerous branches to it, corresponding to the smaller
tributaries. The phenomena observed authorizing this generalization are striation
and the transport of bowlders. The test cases are where the movement has been
in direct opposition to the general southeasterly current. Thus, on adjacent ledges
two miles north of Hanover, there are striae pointing X. 60° W.„and others S. 20°
W., the first being tributary to the second, and less deeply scored. Next, there
are a dozen excellent examples of the westerly transportation of large blocks of a
peculiar protogene-gneiss. These occur in Lebanon, Hanover and Oxford, and in
a few cases there are stria? to correspond, trending southwesterly. This particular
rock occurs only on tin- eastern side of the valley, and it is not possible, therefore,
to say that its fragments were transported by ice in the course S. .">0° E.

2. Near the upper limit of the valley striations there are several examples of
the S. 30° E. course, which are isolated and situated in the midst of the S. 10° W.

4 PROCEEDINGS OF ROCHESTER MEETING.

markings. So far as observed, the first occupy depressions in the ledge, or else are
located on tlic lee side of the valley scorings. Our inference is that the S. 30° E.
markings were mice quite abundant and have been mostly obliterated by the later
local glacier. These examples are not confined to the eastern border of the valley-
but have been found elsewhere in the lower regions.

:;. While it cannot be regarded as a universal fact, many observations show that
Hat bowlders imbedded near the surface of the till have been striated by the valley
movement as well as by the older action. Hummocks of till can be referred to
either of the movements by observing these directions. It would appear that the
older till had been deposited before the local glacier had an existence. Agassiz
has described this same condition of things in the Bethlehem glacier. The most
obvious effect of the later movement has been the removal of the rough blocks
from the surface of the older till, and hence smoothed hummocks indicate a later
and local movement.

4. Bowlders have been carried by ths southeasterly movement entirely across
the valley and lodged upon the farther side. As our studies have been mainly
confined to the depressed region, many cases of this kind have not been observed.
The best illustration of it is the presence of numerous bowlders of the mount
Ascutney granite in Claremont and Newport, New Hampshire. This mountain
lies in the midst of the S. 10° W. striation, but blocks have been carried from it
toward the southeast, evidently before the glacier commenced to move down the
valley. Others have been carried southerly, as if caught by the later current.

5. As a rule, the line is sharply defined between the two directions of striation.

6. The valley movement reached the altitude of 900 feet above the sea in Clare-
mont, 1,000 to 1,800 feet in Hanover on the eastern border. 1,900 feet on the western
border in Norwich, Vermont, and perhaps 2,500 feet on mount Ascutney. This
mountain is a cone, somewhat west of the median line of the valley.

7. The noted esker described by Warren Upham between Windsor, Vermont,
and Lyme, New Hampshire, occupies the area in question, and the stones found in
it correspond to ledges on the west and north, but not to those on the eastern side
of the valley. Pebbles of porphyry from the White mountains can always be found
among them by a diligent search. These could not have been brought by the
general ice movement of S. o0° E. The distance of transportation is often as much
as sixty miles.

The evidence of the presence of a Local glacier down the Ammonoosuc river, a
principal tributary of the Connecticut, is more pronounced thananything that can
be adduced for the area now being discussed. It must have been the upper part of
the same local "lacier.

The papers by the earlier authors were based upon the notion that a single ice
sheet mdy is required to account for all the glacial phenomena, and that the ( !on-
necticut Valley glacier came into being in the decline of the aires after the ice had
ceased to be supplied from Canada. The facts, so far as known in New England,
do not nec issitate the existence of more than one ice age, but it is conceivable that
the system of glaciers radiating from the Green and White mountains may repre-
sent a second Lee sheet. In this connection the attention of glacialists is called to
the interesting southwesterly striation found upon certain highlands in southern
Vermont and western Massachusetts, as described in < reology of Vermont, volume
1, page 7o. These evidently represenl a phase of glaciation different from the on,,
described in this paper.

C. H. HITCHCOCK THE CONNECTICUT VALLEY GLACIER. 0

A free discussion followed the reading of this paper. Professor W. H.
Mies, speaking of his observations in the Alps, said —

About the Matterkorn and the Weisshorn I have observed thin glaciers with a
movement different in direction from the thicker glaciers which formerly existed
in the same places. I believe that under some conditions the upper surface of a
wlacier mieht have a different direction of movement from the lower surface, and
have seen glaciers moving over till, kanies. etc. In one instance I had the fortune
to observe under favorable conditions a -lacier passing over a surface sparsely
strewn with bowlders, and at one point found that a bowlder was being slowly
pushed forward by the ice, but at the same time the body of the glacier moved
much more rapidly than the bowlder, so that its bottom was marked by a long-
groove extending some yards down stream from the bowlder.

Professor I. C. White observed —

Contrary to my former belief, I now know of no mountains in northern Penn-
sylvania which were not buried in the Pleistocene ice sheet.

Mr McGee remarked —

The paper and the discussion suggest a feature ofice movement not alwaysappre-

ciated. which is well exemplified in northeastern Iowa about the margin of the
driftless area. There were in this region two ice invasions of approximately hut
not exactly equal extent : in the first the ice advanced farther in the north and
not so far in the south as in the later invasion, so that the drift borderingthe
driftless area represents the lower till or older sheet in the north, the upper till or
later sheet in the south. >s~ow both in the north, about the headwaters of < >neota
river, and in the south, about the lower reaches and tributaries of the Maquoketa,
there is a remarkable relation between the elements of the topography and also
between the distribution of the drift and the surface configuration — a relation best
displayed in southeastern Jackson county and northeastern Clinton county. Here
the characteristic curves of the glacial topography pass gradually into the more
strongly accented lines of the water-cut topography by which the driftless area is
distinguished, and it is significant that the transition from ice-molding to water-
carving is not only horizontrl hut vertical — that first the bottoms, later the mid-
sides, and finally the rims of the valleys lose the glaciated curves and assume the
water-cut angles ; and this is especially true of the transverse valleys. Moreover
in some cases the transverse valleys are partly lined with an ice laid deposit differ-
ing from the prevailing drift of the region in that it is made up almost wholly of
local debris, sometimes apparently removed lint a few feet or rods from the parent
ledges; while even the furthermost traces of the drift are made up predominantly
of far-traveled crystalline rocks, and occupy faintly glaciated summits some miles
beyond the limit of ice-molding in the valleys. In brief, Loth the distribution of
the drift and the topographic configuration indicate that the thin margin of the ice
bordering the driftless area first pushed into and filled certain transverse valleys.
and then rode over the imprisoned ice as on a bridge, the surface of slip being
transferred from the bottom of the valley to the plane of its rim. In valleys oblique

G PROCEEDINGS OF ROCHESTER MEETING.

to the ice-flow the slip appears to have been divided between the valley-bottom
and the plane connecting its walls.

Mr Warren Upham said —

Instead of attributing the courses of glaciation in the Connecticut valley to a local
glacier, as suggested by Professor Hitchcock, my observations of the glacial drift in
thai valley and over the adjoining country lead me to think that the striae bearing
toward the south and west of south are due to local deflection of currents of the
ice sheet during the time of its departure, rather than either to any glacier later-
existing there or to longer continuance of a remnant of the ice sheet there than on
the higher land at each Hide. The Connecticut valley esker (called a kame in
Geology of New Hampshire, volume iii) was traced by Professor Hitchcock and
myself along the axis of this part of the Connecticut valley for a distance of about
twenty-five miles, from Lyme. New Hampshire, to Windsor, Vermont. It is
believed to have been deposited in the ice-walled channel of a superglacial stream
near its debouchure from the ice sheet to the land from which the ice had retreated.
The size and extent of this esker and its material, which is obliquely bedded gravel
and sand without bowlders, show that it was formed by a large superglacial river
draining a considerable area of the melting ice sheet. When the ice had become
thinned by ablation, its surface here descended from each side toward the glacial
river by which the esker was being formed, and there was probably also some
indentation orembayment of the receding glacial boundary at the river's mouth in
the valley. At this time the currents of the ice sheet which had passed southeast-
ward even in the bottom of the valley, as known by the oldest sets of strife there
noted by Professor Hitchcock, became deflected, as I think, toward the south and
west of south, taking the course of the valley, in obedience to the law that the
currents of the outer part of the ice must everywhere turn perpendicularly' toward
its edge.

Professor Niles added —

The Alpine glaciers suggest a relation between ice and topography quite different

from that assumed by Mr Upham. During past ages glaciation was much more
extensive in the Alps than at present ; yet as the ice retreated, it did not withdraw
from the valleys but disappeared from the divides and shrank into the valleys ;
and to-day, as probably at every stage since the Alpine ice reached its greatest ex-
tension, the margin of the ice is not indented by notches coinciding with the val-
leys, but is marked by streams of flowing ice pushing far below the general snow
level.

Mr McGee added—

While analogies drawn from Alpine glaciers are of great use in researches con-
cerning ancient glaciers of this country, it should be borne in mind that ice-work
is not necessarily similar in regions of high relief like1 the Alps, and in regions of
low relief like the plains of | he Mississippi valley and perhaps also the plateaus of
New England. In regions of high relief the terrestrial surface is rugose and the
general flow of the ice is obstructed by the inequalities. Accordingly, while the

C. H. HITCHCOCK THE CONNECTICUT VALLEY GLACIER. 7

glacier may, if of continental type and of sufficient thickness, assume a fairly uni-
form general slope and a moderately definite direction of general movement, trie
prevailing movement, particularly in the lower portions of the sheet, may be purely
local and determined by the local slopes. This predominance of local over general
movement is magnificently illustrated along the lower reaches of Frazer river in
British Columbia, where the lesser mountains, up to three or four thousand feet
in altitude, are converted into huge tors; but while the prevailing trend of the
great flutings in which the direction of flow is recorded is toward the coast, the
trend is by no means uniform, and many flutings indicate prevailing movement
down the slopes, such as might be expected in a slowly settling neve. Now in such
regions as British Columbia and the Swiss Alps, this local downward impulse must
so far preponderate as to keep the valleys filled, howsoever rapidly ablation may
progress, leaving the divides to be first laid bare. On the other hand, there is
good reason for believing that in the plains of the upper Mississippi valley the ice
pushed forward under a general impulse which so far preponderated over the local
impulse down the gentle slopes that when ablation commenced, superglacial streams
were formed and gradually cut through the ice and into the subterrain, so that the
entire surface became diversified by a drainage corresponding in many respects to
that of to-day — in short, in northeastern Iowa at least, this superglacial drainage
was superimposed upon the land surface and remains to-day a record of the sur-
face configuration of the continental glacier. These types of glacial action must
be carefully distinguished; but there is perhaps a question as to which type was
represented by the ice-work of New England.

Profess* >r ( Jlaypole drew illustrations from Alpine glaciers. He thought
the Connecticut valley glacier more comparable to Alpine valley glaciers,
and particularly to the lower part of the Mer de glace.

Mr Gilbert regarded the possibility of upper ice moving over inferior
ice as demonstrated. He had observed phenomena which nothing else
could explain. In the " finger lakes " of New York each valley has been
shaped by undercurrents in the ice, while the region lias been planed
differently.

Professor Hitchcock regarded the Connecticut valley glacier as a local
glacier from the White mountains toward the close of the glacial episode.

Professor John C. Branner read the next paper :

THE OZARKS AND THE GEOLOGICAL HISTORY OF THE MISSOURI PALEOZOIC

BY G. C. BROADHEAD

Remarks were made by J. J. Stevenson and H. S. Williams.
The Society then adjourned until the following day.

8 proceedings of rochester meeting.

Session of Tuesday Morning, August 16

The Society assembled at 10.15 o'clock a m, President Gilbert in the
chair.

The first paper read was —

PHASES IN THE METAMORPHISM OF THE SCHISTS OF SOUTHERN BERKSHIRE

BY WILLIAM II. HOBBS

This paper is published elsewhere in this volume.

The next paper was then presented by the author, and was illustrated
with maps and drawings:

THE ONEONTA SANDSTONE AND ITS RELATIONS TO THE PORTAGE, CHEMUNG

AND CATSKILL GROUPS

BY .1 i.MES HALL

During a long discussion, Professor H. S. Williams spoke as follows :

It is difficult to map such formations, the physical conditions of deposition being
related to the faunas in a very complicated manner. The physical conditions
change the character of the deposits, while the fauna may persist; a series of dis-
similar rocks being together one faunal formation. In determining the extent of
formations paleontology outranks lithology.

In reply to a question by Professor J. J. Stevenson, Dr Hall said —
The Chemung wedge is lithologically distinct as well as in its fossils.

Professor Stevenson compared Dr Hall's section of strata with his own
New York section and with Professor I. C. White's observations in Penn-
sylvania. Professor White stated that a similar formation extends from
New York to White Sulphur springs, in Virginia, and even into Ken-
tucky. He -would call it all Chemung. Professor E. W. Glaypole spoke
in compliment of the paper, which contained observations made before
many Fellows of the Society were born. He said that in Ohio shales re-
place the sandstones of New York and Pennsylvania. During Devonian
time physical conditions greatly changed in a few hundred miles from
east to west; in western Pennsylvania changes occurred within an extent
of only twenty-five miles. The President spoke of the classification of
formations and the principles of nomenclature, and remarked that nature
is more transitionary than our nomenclature can adequately present.

In closing the discussion Dr Hall spoke of the Long persistence of
faunas, through important changes of receding and readvancing sea-

t

WARREN UFIIAM — ACCUMULATION OF DRUMLINS. 0

shores, local deepening of the ocean, etc. For colors on maps he pre-
ferred designating the lithology.

This paper is printed in full elsewhere in this volume.

The concluding paper of the morning session was read in the absence
of the author by Mr R. S. Woodward :

FINITE HOMOGENEOUS STRAIN, PLOW AND RUPTURE OF ROCKS

BY G. F. BECKER

This paper is printed in full in the succeeding pages of this volume.

Session of Tuesday Afternoon, August 16
The Society was called to order by President Gilbert at 2.10 o'clock.
A paper was read by the author under the following title :

CONDITIONS OF ACCUMULATION OF DRUMLINS
BY WARREN UPHAM

A short abstract of this paper is given in The American Geologist for
October, 1892, volume xii, page 218, and it is published in full, with
additions, in the same journal for December, 1892.

Professor R. D. Salisbury remarked —

It seems to me that the use of the term " englacial drift " is objectionable. I re-
gard the foliation of drumlins as due to great pressure. The arrangement of drumlins
is not parallel to the terminal moraine ; they are sometimes at right angles to it.
Drumlins seem to me to he a normal feature of the drift and ought to be common ;
their absence is more singular than their occurrence. Some are found at right
angles to the direction of ice movement, but they were always formed near the ice
margin, and were englacial and subglacial.

Mr F. J. H. Merrill remarked—

I have found Cretaceous rocks in the Long island drift hills, which seem to me
to have a bearing on the question and to indicate the subglacial origin of the drift.

Mr W J McGee said—

I agree with Professor Salisbury in regarding drumlins as normal phenomena.
Their formation is illustrated in homely fashion by the frequent accumulation of
masses of debris beneath any heavy body dragged on the ground; they well ex-

II -Bull. Gkol. Soc. Am., Vol. 4. 1892.

10 PROCEEDINGS OF ROCHESTER MEETING.

emplify the physical law that " starting friction " is greater than " moving friction."
They should be looked for, not in the area of active glacial degradation, but about
the critical line at which deposition began, i e, the point of oscillation between
degradation and deposition.

Mr Upham remarked —

I musi continue to regard the isolation and strange distribution of drumlins as a
very singular, important and unexplained feature.

The next paper was —

THE EXTRA-MORAINIC DRIFT OF THE SUSQUEHANNA VALLEY

BY G. FREDERICK WRIGHT

Professor R. D. Salisbury and Mr W J McGee remarked upon the
matter of the paper, challenging the observations and inferences of the
author.

The next paper was as follows :

A NEW T.ENIOPTERID FERX AXD ITS ALLIES
BY DAVID WHITE

Remarks wrere made by Professor E. W. Clay pole and by the author.
The paper in full is printed in later pages of this volume.

The twro following papers w ere read consecutively by the author :

THE OVERTURN OF THE LOWER SILURIAN STRATA IN RENSSELAER

COUNTY. N. Y

BY A. S. TIFFANY

ANCIENT WATERWAYS.
BY A. S. TIFFANY

[Abstract]

The writer gave a brief account of an ancient waterfall in a paper read before the
American Association for the Advancement of Science at Ann Arbor, and published
in pamphlet form in 1885. This waterfall eroded the hard, horizontally disposed
Corniferous limestone of what is now Rock island (Illinois) to a depth of 70 feel
and a width of 900 feet. The cavity was afterward filled with Coal Measure shales.
The boring of artesian wells in [llinois and Iowa has since developed a number <<\'
excavations of still greater depth filled with drift.

\t Dixon, Illinois, at an altitude of ris feel above sea-level, a well drilled by Mr
Wilson ran through L50 feel of bowlder clay, though the < lalena and Trenton lime-
stones of the vicinity rise in cliffs many feet above the top of the well see Geol.
111., volume v. pages H'S-130).

A. S. TIFFANY ANCIENT WATERWAYS. 11

At Victor, Iowa county, Iowa (elevation, 806 feet), an artesian boring went
through 348 feet of drift, while at Homestead, 22 miles eastward (elevation, 86(3
feet), the Kinderhook lias but a light covering of drift. Again, at Wilton, Musca-
tine county, Iowa (elevation, 672 feet), about 50 miles east of Homestead, an artesian
well went through drift, including a large bowlder, to a depth of 300 feet ; while at
Limekiln, six miles northwestward, the Niagara limestone is in place at a higher
elevation, and at Moscow, only four miles west of Wilton (elevation, 652 feet}, the
Hamilton shales form the river bluffs.

Phenomena analogous to those of Eock island occur in Missouri, as shown by the
Report on Coal, published by AVinslow in 1801. This preliminary report gives a map
of the coal mines and coal pockets in rocks of different ages in twenty counties.
They are horizontally disposed basin-shaped cavities, with diameters of 800 to 1,000
feet, from j;0 to 80 feet deep, filled with strata of coal and shale, bituminous and
cannel coal frequently occurring in the same pocket. These pockets range from the
margin of the Coal Measures in place to 120 miles distant from them. Swallow
located 23 of these pockets in Cooper county, four of them lying within five miles
above Booneville. Since Swallow's report was published, many more of these
pockets have been explored and the coal worked out. They extend to near Boone-
ville, and lie in close proximity to the beds from which Messrs Blair and Sampson
and the writer made large collections of Keokuk crinoids, the Keokuk rocks rising
in the sloping cliff more than 50 feet above the coal. The coal beds vary in thick-
ness from 20 to 30 feet, while the accompanying shales are very thin. According
to Swallow, these abnormal deposits are found in ravines and cavities of denuda-
tion in rocks of all ages, from the Archimedes limestone down to the Calciferous.
The well-known bed in Calloway county is said to be over 80 feet thick.

These excavations in rocks of different ages show the enormous erosion which
took place in the Mississippi valley anterior to the coal period, and the basin shape
of some of them suggests that they were produced by ancient waterfalls.

Remarks were made by E. W. Claypole and Samuel Calvin.

The three following papers were read by title :

SOME DYNAMIC AND METASOMATIC PHENOMENA IN A METAMOEPHIC CON-
GLOMERATE IN THE GKEEN MOUNTAINS

BY CHARLES L. WHITTLE

PRELIMINARY NOTES ON THE GLACIATED AREA OF NORTHEASTERN KANSAS

BY ROBERT HAY

THE THICKNESS OF THE DEVONIAN AND SILURIAN ROCKS OP CENTRAL NEW

YORK

BY CHARLES S. PROSSER

The President made a few appropriate remarks and declared the meet-
ing adjourned.

12

PROCEEDINGS OF ROCHESTER MEETING.

Register of the Rochester Meeting, 1892

The following Fellows were in attendance at the meeting

Henry M. Ami.
John C. Branner.
Samuel Calvin.
Edward W. Claypole.
Aaron H. Cole.
Herman L. Fairchild.
P. Max Foshay.
Homer T. Fuller.
G. K. Gilbert.
James Hall.
C. Willard Hayes.
Robert T. Hill.
Charles H. Hitchcock.
William H. Hobbs.
H. C. Hovey.
Joseph P. Iddings.

Joseph Le Conte.
Thomas H. McBride.
W J McGee.

F. J. H. Merrill.
William H. Niles.

R. A. F. Penrose, Junior.
R. D. Salisbury.
John J. Stevenson.
A. S. Tiffany.
Warren Upham.
David White.
I. C. White.
R. P. Whitfield.
H. S. Williams.
Robert S. Woodward.

G. Frederick Wright.

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA
Vol. 4, pp. 13-90 January 3, 1893

FINITE HOMOGENEOUS STRAIN, FLOW AND RUPTURE OF

ROCKS.

BY GEORGE F. BECKER.

(Presented before the Society August 16, 1892.)
CONTEXTS.

Page.

Phenomena and Plan of Discussion 14

Evidences of Movement 14

Scope of the Inquiry 15

Finite rotational Strain K>

Limitations of the Problem 16

Displacements 17

General Conditions 17

Strain Ellipse IS

Rotation 19

Lines of constant Direction 20

Simple Strains 21

Pure Rotation 21

Dilation 21

Shear 22

Compound Strains . . Z I

How treated 23

Pure Deformation 23

Shearing Motion or Scission 2-1

Two Shears in the same Plane 25

Plane undilational Strain 26

St rain due to Pressure 29

Elongation 30

Planes of maximum tangential Strain 30

Position of undistorted Planes 30

Planes of maximum Strain '■'< 1

Angular Range of undistorted Planes .".1

Case of tri-dimensional Strain :;:;

Numerical Example of Strain 34

Finite Stress 35

Relation of Stress and Strain 35

Stresses in a Shear 36

Simple Pressure 37

III-Bull. Geol. Soc. Am., \'..i,. -i, 1892. (13)

14 G. F. BECKER FINITE STRAIN IN ROCKS.

Page.

Meaning of Hooke's Law 38

St less System 40

Lines of unaltered Direction 4:!

Properties of Matter 44

Viscosity 44

Flow 4o

Relation of plastic Solids to Fluids 46

Rupture 48

( ideological Applications 4i»

Cases to be considered 49

Effect s i if direct Pressure 50

Rigid Disk in resisting Medium .">:;

Inclined Pressure arid yielding Medium 55

Inclined Pressure and unyielding Resistance . 56

Partial Theoiy of the Spacing of Fissures 57

Examples of inclined Pressure 61

Distortion on Planes of maximum Strain f>4

Various Results of Strain 65

Theory of slaty Cleavage 66

Influence of Shock 66

Secondary Action on ruptured Pocks 68

Effect of tensile Stresses 68

Review of Theories of slaty ( Jleavage 71

Why needful 71

Origin of Jointing 72

Jointing and Cleavage 75

Phenomena of slaty Cleavage 7">

Theories of slaty Cleavage 77

( tbjections to Plypothesis of Heterogeneity 79

Analysis of Experiments 80

P>ehavior of included Grit Beds and Fossils • . 83

Conclusions as to Slate 86

Summary 87

Phenomena and Plan of Discussion.

Eoidences of Movement. All observers are aware that few. rock masses
are continuous for any considerable distance. It is seldom that more
than a few yards of a rock exposure can be examined without revealing-
joints, fissures or slickensides. Still more frequently rock masses show
slaty or schistose cleavage* impressed upon them by dynamical causes.
In a very great proportion of such cases a little attention also discloses

♦ Schist and the adjectives derived from it are used in literature in somewhat variable senses.
As I use it, schist denotes eleavable rocks which an- allied to slates, but in which tin- cleavage
surfaces arc not all sensibly parallel to on< another as they air in true slate. By no means are
schists all crystalline of metamorphic.

FAULTS, JOINTS AND CLEAVAGE. 15

the fact that the partings are locally arranged on a definite system. In
slaty cleavage the cleavage planes are substantially parallel and very
close together ; in flags of the slaty class the intervals between cleavage
pianos are greater ; in schists the partings range through small angles, and
in these last rocks there are frequently two sets of partings, each cleavage
making a small angle with others of the same set, but a large angle with
those of the other set. Where the rock is divided by cracks these are
often parallel and spaced with a considerable approach to uniformity.
Sometimes they occur at a fraction of an inch from one another, while in
other instances they are rods apart. In still other cases there are two
systems of such cracks crossing one another at right angles, or at angles
which approach to right angles. Not infrequently such a double system
of fissures is accompanied by a second of like character, at right angles to
it, dividing the rock into polyhedral fragments of greater or less size.

Slaty cleavage is at present regarded by most geologists as due to a
pressure acting in a direction perpendicular to the planes of cleavage,
and this opinion is supposed to be well supported by experiments.
Indications are not wanting, however, that many observers are ill satisfied
with this explanation. Less attention has been paid to jointing, concern-
ing which there is no consensus of opinion. By some it is considered as
due to tensile stresses, while others insist on its intimate association with
cleavage. Jointing is also often treated as distinct from faulting and as
being unaccompanied by any relative movement of the joint walls. No
systematic attempt appears to have been made to elucidate these various
structures, which are generally recognized, however, as at least sharing a
dynamic origin. Even the experiments on cleavage seem to me not to
have been studied with as much care as they deserve.

Scope of the Inquiry. — Orogeny can never be satisfactorily discussed
until the dynamic significance of cleavages and cracks is clear. A neces-
sary step toward this end consists in the elucidation of those areas, great
or small, throughout which the phenomena are uniform; for, however
complex the conditions may be in any body of rock, they may be con-
sidered as uniform over a sufficiently small fraction of the whole mass.

Even this seemingly modest step cannot be completed in the present
state of science. In the mechanics of artificial structures and machinery
it is sufficient to discuss very small deformations, for such only are ad-
missible. In geology this is wholly insufficient, the strains frequently
being of enormous amount ; so great indeed that laboratory experiments
hardly aid one to conceive that they are possible. Yet there is no doubt
among geologists that pebbles, even of quartzite, in conglomerates are
not infrequently elongated by pressure to double their original length
without rupture. Thus in geological mechanics it is absolutely essential

IV— Bum,. Geol. Son. Am., Vol. 4 18!)2.

16 G.F.BECKER — FINITE STRAIN IN ROCKS.

to consider finite strains as well as infinitesimal ones.* Now, to discuss
such strains completely it would he needful to know the relation between
finite strains and the forces which produce them. This relation is not
yet known.

One might infer that until it were ascertained discussion would he
useless. I hope to show, however, that many relations of finite strain
can he elucidated without the assumption of any law connecting stress
and strain, and that these relations are of great assistance in the study
of orogeny.

The general principles governing finite distortion have, of course, heen
indicated by natural philosophers; hut little attention has heen given
to their development, because the theory of finite strain is needless for
computation of machinery, while this subject will not offer much purely
mathematical interest until the stress-strain law is known experimentally.
In particular, but little attention has been paid (so far as I am aware)
to the planes of maximum strain, which turn out to be those in which
geologists have a special interest. f

In the following pages the attempt will lie made to develop all the
manifestations of uniform or homogeneous finite strain in rock masses
regarded as isotropic, exhibiting viscosity and capable of flow, which can
be elucidated without assuming a law connecting stress and strain. For
this purpose finite strain must first be discussed by itself; then it must
he considered just how far the relations of stresses are capable of coor-
dination with those of strain. The influence of viscosity and solid flow
must next be shown. Readers willing to assume that these subjects
have been logically treated will probably skip them and proceed to the
geological applications which follow. Finally, the results will be com-
pared with actually observed phenomena and with the experiments
which several investigators have made on slaty structure.

FlNITli ROTATIONAL STRAIN.
LIMITATIONS OF THE PROBLEM.

The mechanical effects short of rupture which force can produce in
any mass are translation, rotation, dilation and deformation. The effects
of mere translation may be considered separately from the other effects of
force, or, in other words, one may consider these other effects relatively
to some chosen point of the body itself.

* I have previously endeavored t" show that some fissure systems are satisfactorily explained on
the hypothesis of small strains : Bull. Geol. Soc. Am., vol. 2, 1891, p. 49.

f < tn finite strain consult Thomson and Tait, Nat. Phil., 1879, sec. L81 ; and Ibbetson, Math. Theory
of Elasticity, 1887, p. 09. 1 am much indebted t" l><ith authorities.

DEFINITION OF HOMOGENEOUS STRAIN. 17

If any one point of a body is fixed in space, the mass can be brought
from its original orientation into any other orientation by simple rotation
about some one axis passing through the fixed point. This is a well
known and very fundamental theorem, one of the many which bears
Euler's name.

In homogeneous strain each elementary cube of the mass is deformed
in the same manner as any other; each straight line in the unstrained
mass therefore remains a straight line after strain, being elongated or
deflected to the same extent as any of the lines parallel to it, and all lines
originally parallel remain parallel. Hence any sphere in the unstrained
mass becomes an ellipsoid, and all such ellipsoids are similar.

Irrotational strain is a term applied to a change in form and dimen-
sions unaccdmpanied by any change in the direction of the axes of the
strain ellipsoid. It is manifest that any dilation and any desired ratio
between the axes of the strain ellipsoid can be produced without chang-
ing the direction of these axes.

Hence if the changes in a homogeneously strained elastic mass are
regarded relatively to any one point of it, any change in the relations of
its parts may be considered as compounded of a rotation about a single
axis into the required orientation and an irrotational strain.

There is no necessary connection between the axes of strain and the
axis of rotation, and the latter will not in general coincide with any of
the strain axes. The rotation in the general case is resoluble into three
partial rotations about the three strain axes.

For the purposes of this paper, it is both necessary and sufficient to
examine the conditions affecting the mass in the principal sections of the
strain ellipsoid. This is equivalent to selecting any one such section and
considering the movements relatively to it. When such a selection is
made, the rotations of the plane itself on axes drawn in it are eliminated,
and only the rotation of the mass about a line perpendicular to the plane
of reference retains its significance.

The first subject of discussion therefore is an ideally elastic mass with
one point fixed when subjected to any distortions, however great, which
will produce rotation about not more than one axis of the strain ellipsoid.

DISPLA CEMENTS.

General Conditions. — Let the center of inertia of a mass remain at rest;
let any other point or points of it be moved in planes parallel to the x y
plane without limitation, provided only that the strain shall be homo-
geneous, but let every plane originally parallel to that oixy remain
parallel to it, so that deformation parallel to o % shall consist simply of

18 G. F. BECKER FINITE STRAIN IN ROCKS.

changes of length. Then, if x y are the original coordinates of any point
and / y its final coordinates these positions are connected by linear
relations,

a! = (l + e)z+ by; y' = ax + (1 + /) y; / = (I + g) z;

or,

(1+/K-V . v _ (1 + e) y' - «*' . _^_

(1 + e) (1 +/) - ai " (1 + «) (1 +/) - «6 ' 1 + 1/

Here a, &, <?,/, <? are absolutely arbitrary and have the same value at
all points of the mass.* They are the coordinates after strain of par-
ticular points. Denoting x = 1, y == 1, z = 1, by (1,1, 1), points originally
at (1, 0. 0), (0, 1, 0), (0, 0, 1), are transposed to (1 + e, a, 0), (b, 1 +/, 0),

(0,0,1+flr).

When the strain is so small that the squares of the displacements are
negligible, a, b, e, /, g are to be treated mathematically as infinitesimal ;
consequently any formula in terms of this notation can lie converted
into the forms appropriate to small strain simply by neglecting powers
of a, b, e,f, g, higher than the first.

Strain Ellipse. — The sphere x2 + yz + z" = 1 is converted into an ellipsoid,
which is found by substituting for x, y and z their values in terms of the
accented variables. The section of this ellipsoid by the x y plane is an
ellipse with semi-axes A and B. Its equation is —

j(l+/)2-f a,}a!"-2|&(H-/) + a(l + 0}^+{a + c), + 6s}^f

= {(l + e)(l+/)-a&}'. (i)

When 6 (1 +/) 4- a(l + e) is a positive quantity the major axis of this
ellipse makes a positive acute angle with o x. Well-known properties
of the ellipse show that its area is the same as that of the circle — ■

*'2 + V'2 = (1 + c) (1 +/) — oft - A B, * (2)

and that the axes may be found from the equation —

(A ± By = I (1 -I- e) ± (1 + /) Y + (« + b)\ (3)

*The letters e,/and g are used in the same sense as in Thomson and Taifc, Natural Philosophy,
but I have not found it convenient to use a and o as they are there employed.

FORMULAS FOR STRAIN ELLIPSE. 19

The third axis of the ellipsoid is C= 1 + g> Iff is the length of any-
one of the axes, A, B and G are the three roots of the cubic —

(n-AUv-B)(ji-0) =

1 f.»

| 9 — (1 + flr) | [f2--f !/ (1 + « + 1 + /)2 + (a -" ^)2 +

(l + «Xl+/)-«*} = 0. .(4)

The volume assumed after distortion by the unit cube may be called
/,3 = A BC=(1 + g) •[ (1 + «)(!+/)- a& } . (5)

A3, and —

Rotation. — The limitations of this discussion imply that the plane of
A G can only revolve about G, so that the position of this plane is de-
termined when the position of A is known. The angle which A makes
with o x is, say, v, and this angle can immediately be inferred from (1)
by a well-known formula which gives —

a2 — &' + (l +/)'--( l+«)'

Since the plane i? 0 is at right angles to that of A G, its position follows.
To find the position which the same material lines A and B occupied in
the unstrained mass, it is convenient to remember that they must have
been at right angles to one another before strain as well as after it ; for
mere rotation changes no angles, and irrotational strain is by definition
a deformation in which the ellipsoidal axes maintain their direction.
Hence, if// was the angle which the fiber A made with o x before distor-
tion, its equation was y\x == tan //, and by the displacement formulas

y' a + (1 + /) tan ft

tan v = — = -rz — : — s — ,—j—,

x (1 + e) -f- b tan ft

The angle which the other axis made before strain was ,»■ + 90°, so that
tan (fi + 90°) = — cot ft, while after strain it becomes v -f- 90°. Hence —

tan 0 + 90°) = ?~(l+flZ* = ~ «* '■

v J ( 1 -\- e) — b cot fl

20 G. F. BECKER FINITE STRAIN IN ROCKS.

From these two equations v can at once be eliminated, since tan v cot v = 1.
Writing out this equation and reducing, one rinds—

ton2,«- 2— ^1 + e) + a(1+'> -

P~a!, + (1+/)*— (1 + e)1

The equations for v and p. can be combined to simpler forms. It will
be found on trial that the values already deduced lead to —

tan 0 + A0 = (i + , )_(i+/) 5 tan (v - /,) = (1 + ^(1 + f)- (6)

The angle v — ;>. is the angle of rotation, so that the condition of no
rotation is evidently a = b. When the strain is infinitesimal, a — b is
infinitesimal, while 1 + e + 1 + ,f approaches 2. Hence v — fi is zero
for vanishing strain. If the common limiting value of v and ,u is va, tan
(y + ,a) = tan 2 v0, or —

a 4- b

tan 2 v_ =

(1 + 0 -(!+/)■

Of course this same value is obtained by letting a, b, e and / approach
zero in the formulas for tan 2 // and tan 2 v. Thus v — v0 = vo — //. It
is evident that as rotation proceeds new fibers of matter constantly suc-
ceed one another in the position of axis, the whole series of fibers in the

unstrained mass forming a wedge, v0 — ,a or — — — •

Lines of constant Direction. — Lines parallel to o z retain their direction
relatively to the x y plane throughout strain. If the mass were inflexible
and subjected to rotation, only these lines would maintain their direc-
tion ; but when there is strain two other lines may retain their original
direction, the two coinciding in the limiting case which separates that
of three such lines from that of one.

If /. is the angle which any line in the x y plane makes with o x before
strain and / the angle which it makes after strain, then —

tanx=y-J=ar(1+{)tanx-

x 1 -f- e + b tan /.

If X = /. this gives —

which represents two real lines, unless the quantity under the radical

ROTATIONAL STRAINS. 21

is negative. The two coincide when this quantity is zero, or when
4 ab -f (e — f)3 = 0. The value of tan /- then reduces to ± y —alb,
showing that a and b must have opposite signs. This particular case
occurs in the strain often known as shearing motion, as, for example,
when a rivet is shorn by tension of the plates which it connects. It will
be discussed later.

The condition of no rotation can be derived from tan /.. The equation
represents two lines, and if v.x and ■/.,, are the two angles, tan x1 tan y-.2 =
— a I b. If there is no rotation, the axial lines are lines of unchanged
direction and tan xt tan *.,= — 1, or a = 6.*

SIMPLE STRAINS.

Pare Rotation. — If the mass undergoes rotation without strain, each of
the axes is equal to unity, and h has the same value. Then by (3), e ==f
and a + b = 0, and by (5), (1 -f e)'2 = 1 — a2. Hence tan (v — p.) =
al\/ 1 — ft'2, or sin (y ■-- ,"■) = a. This result can also be derived imme-
diately from the displacement formulas.

Dilation. — When the only strain is dilation, A--B = C —h, whether or
not the displacements cause rotation. • Then by (3) e =/and a + b == 0.
By (2) also (1 + ''■)"' + a2 — (1 +(/)2- The rotation is then given by —

a a

J 1 + « -,/ h* — a2

When there is no rotation, so that the displacements cause pure dilation,
ft = b = 0 and e =f= g = h — 1.

In dealing with dilations it is usually convenient to consider h, the
ratio of dilation, as greater than unity, excepting when its value is
unknown. The volume of a compressed mass is then l//t3, which does
not vanish unless the ratio of dilation is infinite.

♦The length of the lines of unchanged length exhibits a somewhat remarkable relation. Let k
be the length of such a line. Then—

xl = y- = k,

x y
and by the displacement formulas—

?/ _ k — (1 +e) _ a

x b k-(l+f)
This gives—

2£ = l + e + l +/± tfiao + (e—f)*.

If A.'j and k« are the two values of k, then —

fcj fc2=(l +/) (1 + e) — ab,

which by (2) is the product of the semi-axes or A B. Thus the product of these lines remains in-
variable, whether or not they coincide with the axes.

22 G. F. BECKER FINITE STRAIN IN ROCKS.

In any case whatever one may express the axes A and C under the
forms A = A«, C = hp where « and p may be perfectly independent.
Then, since ABC - h3, B =- hjap. The values >*, \jap and p are the values
which A, B and C would have were there no dilation, and upon the
properties of « and p depend those of pure deformation, accompanied by
rotation:

Shear. — A shear is the simplest possihle deformation. It may be de-
nned as an irrotational strain, unattended by dilation, in which one axis
of the strain ellipsoid retains its original length. The unit sphere is thus
converted into an ellipsoid, the axes of which are «, 1, l/«; and a is called
the ratio of shear. It is taken as greater than unity, excepting when it
is dealt with as an unknown quantity.

In dealing with shears it is convenient to employ the following ab-
breviations : *

2 S = « — u~l ) 2 t = a -j- a-1.

These forms imply that *2 — s2 = 1.

The displacement formulas for a shear, the contractile axis of which
makes an angle fl with ox are —

%' = x (t — s cos 2 #) — ys sin 2 # ; i/ = y (a -f- s cos 2 #) — xs sin 2 # ; z* —z.

To verify this statement consider that a = b, so that there is no rotation ;
(j = 0 and (1 + c) (1 +/) — a0 =1) so that there is no dilation; tan
Q, -j- //) = tan 2 v = tan 2 #, showing that the axes of the strain ellipsoid
make angles »9 and >(> 4- 90° with o x; finally b (1 +/) + a (1 + e) is nega-
tive, so that the minor axis of the strain ellipsoid makes an acute positive
angle with o x as required.

When # = 90° these equations reduce to —

x' = xa; y' = yja; z' = z,

and when & = 45°, a case of importance,

x' = xff — ys ; y1 = ya — as ; 2' = 2.

The quantity 2 s is called the amount of the shear. There are various
aspects of this quantity. One way of looking at it is as the sum of two

distortions. The elongation of the major axis is «— 1 and the contrac-

— • ■

*Let a = cot "co; then it is easy to see that o- = l/sin 2 td and s = cot 2 to. Here, as will be show n
later, 2 "to is the acute angle between the circular sections of the strain ellipsoid. The convenience
of s and a- depends upon this fact, and the significance of the formulas is increased by bearing it
in mind. The quantities s and a may lie regarded as hyperbolic sine and hyperbolic cusint "fan
area \J< = In a ; and then !mi° — ■ 2 "to is the corresponding transcendental angle. This view of the
functions, however, is not needful for the purposes of this discussion.

MEASURE AND PROPERTIES OP SHEAR. 23

tion of the minor axis is 1 — 1 / «. The sum of the two is a — a-1 = 2 s.
While 2s measures shear and is not unfitly called the amount of shear,
s might e |ually well have been regarded as the measure of shear ; indeed,
this would have been more convenient, because it would have accorded
with the received nomenclature of stresses.

Many of the properties of shear can be inferred in the simplest manner
from its definition. Since it involves neither change of volume nor of
the area of the strain ellipse, it can consist only in re-arrangement of
matter, each fiber perpendicular to the plane of shear, retaining its
original thickness, length and direction, though shifted to a new position.
Since the major axis of the shear ellipse exceeds unity and the minor
axis falls short of unity, there must be four intermediate radii of unit
length, and the symmetry of the conditions shows that these four radii
form two diameters. Thus there are two diameters winch have the same
length after strain as before strain. These diameters are the traces on the
x y plane of planes passing through >> :. ami these planes undergo no dis-
tortion through strain. In them the circular sections of the strain
ellipsoid evidently lie. All planes parallel to these are also, by the
properties of homogeneous strain, planes of no distortion. Any two
planes of no distortion must stand at the same perpendicular distance
apart after strain as before, for were it otherwise the volume of the ellip-
soid would lie changed.

Thus a shear can consist only in the sliding of planes of no distortion
upon one another and in changes of the angles between the two systems
of undistorted planes.

The behavior during the straining process of the planes of no distor-
tion is of great geological importance ; but as this behavior depends to
son^e extent upon rotation, it appears appropriate to. defer its discussion
until some of the simpler compound strains have been explained.

COMPOUND STRAINS.

How treated. — For the immediate purposes of this paper it is needful to
examine compound strains of several varieties. It seems desirable also
to examine the simpler combinations in somewhat more detail than is
absolutely essential to the results which will be deduced from them in
the subsequent sections in order to give assurance that the geological
deductions are not vitiated by the omission of important properties of
strain. It is to be hoped also that the treatment here submitted may
facilitate the solution of geological problems not touched upon in the
present investigation.

Pure Deformation. — Any pure deformation is resoluble into two shears
at right angles to one another, one axis being common to the two ele-

V— Bum.. Geol. Soc. Am., Vol. 4, 18112.

24 G. F. BECKER FINITE STRAIN IN ROCKS.

mentary strains. This will be demonstrated by a proof that any relation
whatever between the axes A, B and C of the ellipsoid whose volume
is proportional to h3 can be brought about by two such shears. Let
A = ha, B = hy, and let C = hp, where A and B are entirely arbitrary.
Then since ABC = h3 = BJr<i..\, it is evident that 1 / ap = y, or B = hj ap.
Now, if a shear of ratio a is applied axially in the x y plane to the sphere,
^ + V~ + z?' = h2, if will reduce this mass to the ellipsoid .r / <r + i/V +
22 = K1. If a second shear of ratio ft is applied axially in the y z plane
it will further reduce the second axis in the ratio p and elongate the
third axis in the same ratio. Thus the two shears yield an ellipsoid
%* I a2 -p T/VyS2 -f z1 j p1 = /r, and the axes of this ellipsoid are ha} hj aft and
hft, or A, B and C.

A converse proposition is also important. Any number of shears
applied axially to a sphere can 011I37 modify the relations of the axes to
values A, B and C, the volume of the mass remaining proportional to
ABC= h6. Hence any number of axial shears are reducible to two and
not to three, as one might be inclined to surmise. This resolution may
take place mathematically with any one of the axes as the common axis
of the two shears. In most cases, however, considerations of symmetry
point to one of the axes as that common to the two shears.

A simple shear produces relative motion of particles or fibers only in
its own plane. Its only effect on fibers in planes at right angles to its
own is to elongate them uniformly in one direction without any tendency
to the causation of relative motion. Hence .the effects of each shear must
be considered in its own plane, and the relative motion produced by each
of two shears in orthogonal planes is independent.

V —

_ —

^^

v^

t=_ - \ I

t= \ I

V— \ 1

\1 \l

\ I \ I

V — "' — \

Figure 1 Scission.

Shea ring Motion or Scission. — A " shearing motion" is the rather ill-chosen
designation of a strain nearly corresponding to that which occurs when
a bar or plate is shorn by a pair of shears, or when a rivet yields perpen-
dicularly to its axis, say, in a bursting boiler. The term is not happy,
because it seems to indicate that there are shears not accompanied by
motion. It is, of course, from this strain that the term shear was de-

FORMULAS FOR SCISSION. 25

rived, but this has been transferred to the simpler deformation. The
name scission would aptly indicate the "shearing-motion" strain, which
consists in the relative movement of imdistorted material planes, each
sheet of infinitesimal thickness remaining in its own mathematical plane,
as shown in figure 1. The motion can be well illustrated with a pack of
cards.

Scission or shearing motion is that case of strain already referred to in
which there is a single line of unchanged direction in the xy plane, and
it consists of a simple shear compounded witli a rotation of the axes of the
strain ellipsoid.

The most important case of scission is that in which the direction of
the planes of constant direction and no distortion coincide with one of
the axes. If this axis is o x the displacement formulas may be written
simply —

•''' = •'' — 2 ys ; if = y.*

Here 2s = '/ —a-1, the amount of the shear involved. The rotation is
given by —

tan {? — ft) = s ;

and since tan 2 ^0 = tan (y + //) = oo, the axes of the ellipse at the incep-
tion of strain were at 45° to the fixed axes. The quantity 4 ah -j- (e —f)2
becomes zero by the simultaneous disappearance of its two terms. If #
is the angle by which a line originally parallel to o y is deflected by the
strain,

. tan K = b = 2s ,

so that the amount of shear may be defined as " The relative motion per
unit distance between planes of no distortion." f

Two Shears in the same Plane. — The most frequent combination of two
shears in the same plane is that in which the axes of one of these strains
makes angles of 45° with those of the other. If the contractile axis of
one of the shears makes an angle of 45° with o x, displacing .c to ./ and
y to y', the ratio of shear being «, and if the contractile axis of the other

* If the planes of constant direction and no distortion make an angle, </>, with o ./-, the displace-
ments are given by—

x' = x (I +s sin 2 <(>) — ys (1 + cos 2<j>) ; y' = y (1 — s sin 2 <j>) + x s (1 — cos 2 <£).

The product, a b = — s" sin'- 2 0, is an essentially negative quantity. Hence the signs of a and b arc
necessarily different. Compare tin' discussion of formula (7).
-(■Thomson and Tait, Nat. Phil., see. 17").

26 G. F. BECKER FINITE STRAIN IN ROCKS.

shear coincides with oy, displacing / to .<•" and //' to ,'/". the ratio being <>Y.
then the displacement formulas :;: are —

n -j ji V V7 ''s

X = x a. = xax<j — ya s ; y = 2- = £_ — —

a, a, a,

This strain, although the resultant of two irrotational strains, is rota-
tional, since a — b is not zero. It is easy to see that this would probably
be the case, for the first shear alters the direction of every line excepting
those coinciding with its axes, and the direction of these is changed by

the seeond shear. The rotation is given by —

tan (y — ft) = ss1 j ffffu

where 2 <r, = «x + a^1 and 2 sl = a, — a~x.

It is an important fact that when the shears are of infinitesimal amount
this combination becomes irrotational. When a and a, differ infinitesi-
mally from unity, s = e, st = e1} a = 1, gx = 1 and tan {? — /-/.) = ecv an
infinitesimal of the second order.f

The two finite shears are equivalent to the rotation stated above and a
simple shear of amount —

2 \/ t"s{ + ^V.

Plane undilational Strain. — The most general strain treated in this paper
may be considered as a perfectly general undilational strain in one plane,
combined with a shear at right angles to this plane and a dilation. The
more complex effects are confined to the principal plane in which rota-
tion occurs, and it is therefore desirable to reduce the plane undilational
strain to its simplest terms.

One method of resolution consists in regarding the general strain as
compounded of elementary strains symmetrically oriented with reference
to the fixed axes, namely, an axial shear; a shear at 45° to ox; and a
scission, the unchanged direction of which coincides with one of the
axes.

It is somewhat easier to test the results of analysis in this case than to

* When the first shear makes an angle # with ox the formula.-; are —

x" = xai (<r — s cos 2 d) — va-iS sin 2d; y" = " (a- + s cos 2 &) — — s sin 2 &.

Here ab = -s2 sin- 2 i>, anil is essentially positive.

fWhen 1 1 - make an angle & and the ■-train i- infinii in {v — y.) = ee\ sin 2 i>, which

is also an infinitesimal ol the second order, so that any two shears, and therefore any number of
shears of infinitesimal amount, combine to an irrotational strain.

ANALYSIS OF PLANE STRAIN. 27

analyze the general strain. To begin with, changes of notation are con-
venient. The expression —

-2o(l + e)±yi + 4 a2 (1 + e)2

represents two values, one of which is minus the reciprocal of the other.
Let the positive value lie «./, so that the negative value is — «.r2. Then,
if 2 v., = a., -p a~x and 2 s2 - a2 — a~\ it is easy to see that —

— a (1 -p e) = t.a,.

Call the value of sja minus '/... Then —

a = - and 1 -p e '= a./i.. ;

"i

and if one denotes —

«a(l +/)-',

2 ?2 by s„

1 , f = *« + 2 «*.
"3

Thus far only changes of notation have been introduced. To find the
value of b in terms of this notation and for this case, consider that the
sole condition of plane undilational strain is the invariability of the area
of the strain ellipse. This is expressed by —

• (1 + f)(1+/)_a6 = lor6 = 0+fL(l±i)rJ.

/

Introducing the new notation into this expression —

b = — a3 (2 sxv., + •§,).

To interpret these values, suppose the final position of x and y to be
.'"' and //'", so that —

a"' = (1 + e) x -p by = «s J (,; - 2 slV) <r2 - ys2 J ;

y'" - (i +.0 :v + ax = J0r- — ^ «r

"3 "3

This evidently expresses a simple axial shear of ratio a3 combined with
a compound strain. If x" and y" are the displacement values for this
last—

•''" = 0 — 2 «#) *, — ys2 ; v/" = yr., — (.c — 2 ysj «,.

28 G. F. BECKER FINITE STRAIN IN ROCKS.

By substituting x = x — 2 s^y and // = y these become the equations of
a simple shear at an angle of 45° to o x. Finally —

x' = x — 2 s^, ]( = y,

are the equations of a simple scission.

Thus the most general plane undilational strain is resoluble into an
axial shear, a shear at 45° to o x, and a scission in the direction of one of
the axes.

When a= b this general strain reduces to a single shear. Jib I a =
(1 4- e) I (1 +/) = (>-i the strain reduces to two shears or, in other words,
the scission vanishes. If a = 0 and (1 + e) / (1 4- /) = «32 the strain is an
axial shear combined with a scission.*

*A second Resolution.— The above method of resolution is the most convenient for computation,
but it fails to disclose a relation of much geological significance. It is a fact that any plane undila-
tional strain is resoluble either into two shears at an angle # or into a shear and a scission at an
angle <f> The significant difference between these two combinations is that the two shears cause a
relatively small rotation which is an infinitesimal of the second order when the strain is infinitesi-
mal, while the shear and scission produce a large rotation which is of the same order as the strain
when this is infinitesimal. The criterion discriminating the two classes of strains is exceedingly
simple. When a and b have the same sign the strain is invariably equivalent to two shears. When
a and 6 have opposite signs the strain is invariably equivalent to a shear and a scission. As in the
case of the other resolution, it is easiest to discriminate changes of notation from equations of
condition synthetically.

Let a and b have the same sign. Then to show that the strain is compounded of two shears one
may proceed as follows : Adopt the notation —

,(!+/) +«(! + «). Sin2& = -Yba.

a^

2 j/ ab s2 a

Each of these expressions is possible whenever a and b have the same signs, and then only. In
addition, the condition of piano undilational strain is (1 + e) (1 +/) — ab = 1. Here, then, is a
number of equations just sufficient to determine a, 6, e and/. Remembering that 1 + e and 1 +/
are necessarily positive, they give —

a-**"*; b=-ass2sin2&; 1 + e = a8 (<r2- S2 cos 8*) ; 1 +/= *' + Sa- cos 2 *.

Is is easily seen that these values answer to an axial shear of ratio aa and a second shear of ratio 02
at an angle # with 0 x.
Let a and b have opposite signs. This is implied in the expression—

1 _|_ y! —at,

and the condition of plane undilational strain is (1 f e, (I +/) — ab = 1. Purely notative are the
following:

a3 ■ a3 Si

These four equations give—

ffi = Si(lTcos2<fr). & = _a3.Sl(1±C0S9^); i + c = a;j(i +Slsin24>); 1 +/= 1~sl8iw2<fr.
0-3 "3

These values answer to an axial shear of ratio a3 and a scission of ratio a^ The direction of the
scission makes an angle <f> with ox if the given values of a and b arc satisfied by choosing the upper
sign in these expressions. In tin' opposite case the direction of the scission makes an angle 0
with o y.

RESOLUTION OF STRAINS FROM DISPLACEMENTS. 29

The foregoing synthesis shows how a plane undilatio'nal strain maybe
resolved when the displacements are given. Cases also arise in which it
is desirable to find the displacements a, 6, e and / from a known shear
and values of v and //.. If the ratio of the shear is «, the values of «r and s
can he derived from it, and these two values, together with the values of
v -f ;>■ and •> — ,"■ constitute four equations from which a, b, e and / can
be deduced. They give —

a = s sin (y + //) + n sin (y — //) ; 1 -p e = cos Q> — /j.) + s cos (* 4- ;i) •

b = s sin (v + //.) — (7 sin (y — /1) ; 1 +/= cos (y — //.) — s cos (v -j- //.). (S)

These values, substituted in the formulas of preceding paragraphs, show
to what simplest strain system a given rotation and shear are referable.

Strain due /<> Pressure. — For the sake of keeping the discussion of strains
together, it may be assumed here by anticipation that a pressure produces
a cubical compression of ratio h * and two ecpial shears of ratio a at right
angles to one another. For brevity, let —

2 t = a — or1 ; 2 r = a + aT\

Then the displacement formulas for a strain due to a pressure in the
direction -V are —

x' = j (r — t cos 2 <*/) — ■'! t sin 2 # ;y' = \(T + t cos 2 >'/) — j t sin 2 <f/ ;

Z
h

^==?(r + 0.

It will be observed that these formulas are analogous to those for simple
shear.

When the pressure is vertical, so that # — 90°,

, %a . y za

x z'-j]y ^; z = r

If a vertical strain of this kind is combined with a scission or shearing
motion in a horizontal direction, the values of x only will be modified by
the second strain. If x" is the final value of x and 2 sx is the amount of
the shear produced by the scission —

x' - j ~ ^h ; y" = v' ; z" = z' ; and ,i,n <v - *> = * ^T - *>•

*- Here h is taken greater than unity, and is the reciprocal of the value which in a given case
would satisfy (5).

30 G. P. BECKER — FINITE STRAIN IN ROCKS.

Here the rotation is of the same order as the strain and is not negligible
when the strain is small.

If the strain produced by vertical pressure is combined with a shear
at 45°, the value of z will be unchanged. If v., and •*, are the values of a
and s for this added shear, and if/" and //'" are the final displacements
for this case —

x ==TT-5%' y -'-an- h >* = *'> ian (r-~fi = = ^m

In this case, when the strain is infinitesimal, the rotation is an infini-
tesimal of the second order.

Elongation. — Simple elongation (unattended by changes in the area of
the section perpendicular to the direction of elongation) is sometimes
regarded as a simple strain. It may as well or better be considered as
compounded of two shears and a dilation. In discussing dilation it
was pointed out that the three axes of the strain ellipsoid may be written
A = ha, B = Ji jap, C= hp. When the strain is simple elongation in the
direction of JB, ha = 1, hp = 1 and B = h3jAC=h3. Thus elongation
consists of two shears each of ratio h and a cubical dilation h.

In the case of contraction or negative elongation a value \ is to he
substituted for // and A: = 1 jh. Tims contraction is compounded of
cubical compression ljk and two shears. If A is the same in the two
cases, the same shears are involved in each strain but differently com-
bined. In elongation the tensile axes of the shears coincide, while in
contraction the contractile axes coincide.

The same two shears which without dilation would stretch a mass to
an infinite length, when differently combined would reduce it to an in-
finitesimal thickness without cubical compression.

PLANES OF MAXIMUM TAGENTIAL STRAIN.

Position of wndistorted Planes. — Attention has already been called to the
fact that in a simple shear the circular sections of the strain ellipsoid are
undistorted planes parallel to which relative motion takes place, and
further inquiry into them is essentia] to a full elucidation of this strain.
In the other plane undilational strains there are similar plane-, though
their behavior is modified in essential respects. In tri-dimensional strain
the corresponding planes are no longer undistorted, 1 >ut nevertheless
influence the character of the deformation. It seems most logical to
begin with a discussion of the case of simple shear and afterwards to
modify the results for complex strains.

MAXIMUM STRAIN. 31

The circular sections of the shear ellipsoid for which the ratio is a make
an angle with the major axis whose cotangent is a* If this angle is
called m, the amount of shear is —

2 s = a — «-' = cot w — - tan us = 2 cot 2 us = 2 tan 1 90° — 2 us).

Here s, or half the so-called amount of shear, appears as measured by
the divergence from 90° of the angle 2 us between the circular sections of
the shear ellipsoid. A right angle is the value which 2 m assumes when
the strain is infinitesimal.

The original position of the particles constituting the planes of no dis-
tortion, relatively to the fibers which coincide with the axes of the ellipse,
bears a simple relation to en. Suppose the shear to be axial and that the
sphere .>','' + V\ + zi = ^' is converted into the ellipsoid x2/a2 -f y2<r -f
z2 = /r, so that yj ->\ = "'///•'7 then the original position of the material
plane forming the circular section of the shear ellipsoid was dl tan us =
„.= fan (90° — US).

Thus these material planes made before shear the same angle with the
minor axis of the ellipsoid which they make after strain with the major
axis.

Planes of maximum Strain. — It is instructive to regard the planes of no
distortion from another point of view. Consider any two very thin plane
layers in the unstrained mass which include between them the axis o z,
and let the angle which they make with, ox be <p. After strain these
planes will still be planes; they will make an angle cc' with ox and
hni <p = o?- tan <p' or

, / ,n (a? — 1) tan a

Ian ((f — w ) = V— ' — . — H.

a? + tan2 if

The greater the angle cr — y' becomes, the greater must be the tangential
strain. Now this angle and its tangent are greatest when tan <p — a or
when tan <pr = 1/ a = tan us. Thus the undistorted planes arc those for
winch tangential strain is a maximum. For the axes, on the other hand.
<p — <p' = 0, and there is no tangential strain.

Angular Range of undistorted Plane*. — Though at the end of a shear or
other plane strain there are planes which have the same dimensions as
before strain, it is not true that these planes have under-one no distor-
tion. On the contrary, there is but one strain in which any lines escape

* The intersections of the shear ellipse with the circle of equal area are points in these sections,
since the radii of the ellipse retain their original length, say unity. These intersecl ions are given
by-

a-

whence a = ± x I y.

VI— Bull. Oeol. Soc. Am., Vol. 4, 1892.

32

G. F. BECKER — FINITE STRAIN IX ROCKS.

temporary distortion. In general, the circular sections of the shear ellip-
soid consist of different particles when the strain begins from tin <- <■
which occupy the circular sections when tin; strain ends. In other
words, these geometrical planes sweep through a certain angle, coinciding
successively with all the particles in a wedge of the mass bounded by
limiting materia] planes. Futher more, one of the circular sections sweeps
in general through a different angle from that over which tin; other
ranges, so that the rate of movement relatively to the particles is different.
This difference of rate is a matter of much importance when tin; mass
possesses viscosity, as all real matter seems to do.

Piguee 2. — Ra rular Sections.

The square of broken lines is strained to the rhomb in full line?. The full lines intersecting at
iii center are the final axes and lines of no distortion. The broken lines intersecting at the center
show the positions which these same lines occupied before strain. Thelinesi m I v to , which
are drawn only to the outside of the s luare, indie ite the position of the fibers which at the incep-
tion of strain coincided with the major axis and the linos of no distortion. The ■ - mark the

(. I

wedges in the unstrained solid over which the geometrical planes of no distort ion sweep. For
displacement ixample, p. 'A.

The range of the circular sections must therefore be determined, and
it is most easily discussed by examining in the unstrained mass the
limiting angles between which the circular sections will vary when -train
of assigned amount takes place. Thegeneral formulas afford the means
for such a determination.

MAXIMUM STRAIN. 33

When strain'begins the major axis of the shear ellipse makes an angle,
v0, with ox, and the undistorted planes then make an angle of 45° with
the major axis or angles v0 ± 45° with ox. When the strain is complete
the major axis makes an angle, v, with ox, and the undistorted planes
make angles co with this axis. But before strain began this last axial
fiber "made an angle, //., with ox, and the particles constituting the last
undistorted plane then made an angle, 90° — to, with >).. Thus in the
undistorted mass the angles bounding the wedge through which the cir-
cular sections will sweep are v0 ± 45° and <>. ± (90° — ro).

On the side of the minor axis toward which rotation takes place this
range is therefore —

v0 4- 45° - | n + 90° - ro 1 = ro - 45° + i^A

and on the opposite side of the minor axis the range is —

| ,, _ (90° - en) } - (v0 — 45°) = ro - 45° - VJZ^.

The difference of range is thus the angle of rotation, and is actual when-
ever the strain is a rotational one.

In a simple shear, then, there is no difference in range, and the range
on each side is en — 45°. In the case of scission or shearing motion it is
easy to see that 2 (w — 45°) = v — //., so that the range is zero on the side
from which rotation takes place, and one and the same set of fibers are
exposed to maximum tangential strain throughout the process of strain,
while the other circular section sweeps through the maximum possible
angle. In any case of plane strain the difference in range is at once
assigned by the angle of rotation, so that for two shears in the same
plane at an angle of 45° the difference is measured by tan (v — //) =
ss1\o<jv

For plane strains the value of en may be simply expressed in terms of
the displacement coefficients. It is easy to see that —

-j = la a2 en = B\A.

Hence also —

4 AB (1 + e) (1 H 0 - -«/>. (l)]

tan 2 en = {A _ By - 4 ^ _jy + (ft + by2 (■>)

Case of Strain in three Dimensions. — It has been pointed out already
that the relative motions of the particles in the xy plane due to a shear
a are unaffected by an axial shear p in the B (.'plane. The sole effect of
the second shear, so far as the x // plane is concerned, is to change the
length of all lines parallel to the common axis of the shears uniformly in

34 G. P. BECKER — FINITE* STRAIN IX ROCKS.

the ratio 3. Hence if before the imposition of the ft shear a Line made an
angle w with A, this shear will alter the angle w to, say, a», and—

tan <o = ft-1 tan us = 1 / a/3 = B j h. (10)

Lines making the angle to with .1 will not be undistorted when .-; differs
from unity, but they will be lines of maximum tangential strain what-
ever may be the value of ft.

The value of w cannot easily be determined immediately from the dis-
placement coefficients. It can be expressed in terms of the axes for
/,,,/; W = B1 1 AC, but the value of .8/0 is a complicated one, on account
of the inclination of the plane B C.

Rotation is supposed to be confined to the axis 02, and is therefore
unaffected by the shear ft. Hence for strain in three dimensions, as well
as in plane strain, the difference of range of the planes of maximum
strain measured in the unstrained solid is the angle of rotation, v — //..

Numerical Example of Strain. — The application of the formulas devel-
oped may he illustrated by an example. Let —

a =0.1; 6 = 0.3; 1 + «==1.2; l-f/=0.7; 1+g =1.1.

This is a rotational strain, since b > a. Equations (6) also show that
v + (x = 38° 40' and v — /x == — 6° T. If the displacements constituted
a pure rotation, sin (y — <>■) would equal a. As tins is not the ease, there
is strain. Formula (5) gives h = 0.962, so that the strain is a compres-
sive one. If deformation were confined to the xy plane, 1 H- g would
equal h. Hence there are two shears. To find them it is most con-
venient to determine the axes of the ellipsoid from (3), which gives
A = 1.275. B = 0.635, C= 1.1. Then also a = I / h = 1.325, j= C h =
1.143. Equation (1) shows that the major axis makes a positive acute
angle with ox. The rotation, dilation and the ratios of the two shears
are now known.

To resolve the rotation and the a shear into component, plane, undila-
tional strains, let %, bv e1 and^ be the displacements which would pro-
duce only the a shear and the rotation. Then formula (8) leads to these
values — ■

„, =0.0695 : 6, = 0.2872 ; 1 + e, = 1.2572 : 1 -\-f1 = 0.8113,

which give for the elementary plane strains —

a2 = 0.9168 ; o... = 1.2524 ; s, = 0.0708.

The a shear with the rotation is therefore equivalent to a shear with its
contractile axis coinciding with oy of ratio 1.2-324, together with a shear
the tensile axis of which makes a positive angle of 4-3° with ox, its ratio

NUMERICAL EXAMPLE. 35

being l/«2 = 1.0908 ; and lastly, a scission for which sl = 0.0708. Since
<<x and bj have the same sign, the plane undilational strain might have
been regarded as due to the combination of two shears without any scis-
sion, but these shears would not be at 45° to one another.

The value of en is given by tan en = Ija — 0.7545, so that en = 37° 2'.
Had only ax, bv cy and/\ been given, en could have been obtained from
(9), which, of course, gives the same angle.

Idie first fiber to occupy the position of major axis at the inception of
strain made an angle with o x, which was ^0 = (y -f />-)/2 = 19° 20', and at
this same time the positions of the lines of maximum strain were at
v ± 45° ; i. e., at 04° 20' or — 25° 40'. The original position of the fiber
winch eventually constitutes the final major axis was at an angle <>. or
20° 20]' to ox. The original position of the fibers which at the end of
the strain undergo maximum strain was at /.« ± (90° — 03) ; i. c, 75° 18 V
and — 30° 37 ¥. The angles in the unstrained mass bounding the fibers
which subsequently undergo maximum strain on the side from wdiich
rotation takes place are thus, <>■ 4- 90° — w and v0 + 45°, and these differ
by 10° ^Y. On the other side the limiting angles are ^0 — 45° and
/i — (90° — m), which differ by only 4° 57*'. Thus the fibers on the
positive side of the major axis pass through the condition of maximum
strain more than twice as rapidly as do those on the negative side of the
major axis. If the resistance wdiich the mass offers to deformation varies
with the rapidity of deformation (as is the case with real substances), this
difference wrill somewhat affect the results. Had a and b different signs,
this difference would be far greater.

The angle m for this example is by formula (10) 33° 25', so that the ,3
shear changes the direction of the lines of maximum strain by some o\
degrees, though without tending to produce any further relative motion
upon them.

Figure 2 is drawn for the displacements au bx, <\ and /n and illustrates
the range of planes of maximum strain for this example.

Finite Stress.
relations of steess and strain.

In the foregoing discussion the geometrical properties of homogeneous
strain due to given displacements as exhibited on any principal plane of
a strain ellipsoid have been developed, and I am aware of no important
property of such strain which has been omitted. If the relations of dis-
placement to stress (or force per unit area) could be as fully developed,
we should have a substantial basis for a theory of finite distortion, since
however heterogeneous a strain may be, any infinitesimal portion of the
mass is homogeneously strained.

36

G. F. BECKER FINITE STRAIN IN ROCKS.

The relations between finite stress and displacement lack satisfactory
experimental basis and cannot therefore be fully developed, but it is
desirable to show just where knowledge cuds and ignorance begins.

Stresses in n Shear. — From the discussion of the properties of shear, it
follows that the imdistorted planes are necessarily subjected to purely
tangential stresses ; for they are neither elongated nor drawn apart during
strain, while normal forces acting upon them would produce such effects.

The stress phenomena in a shear can be examined as a case of equi-
librium, and such an examination reveals the somewhat important fact
that the planes of maximum tangential stress do not coincide with the
planes of maximum tangential strain.* It also teaches how the two
component forces involved in a finite shear are related, and thus, in spite
of ignorance of the direct relations between stress and strain, the inquiry
is by no means fruitless.

J

r

-Q

i

i

i
i
i

JP

i

i

-* :

i

i
i

a

i

a.

\ i

i

Figure 3.— Stresses infinite Shear.

Let the rectangle o b represent one-quarter of a strained cube and let
— ■ Q and Pbe the stresses (or forces per unit area) holding it in this state
of strain. Then it is easy to find the stress on any plane cutting the x y
plane at right angles along the line a e. Let the normal to the plane
make an angle # with o x. Then —

ab = ac sin >'J ; be = ac cos >>.

If i^and G are the component stresses on ac parallel to ox and o y,
these components must hold the stresses on a h and a c in equilibrium.
Now, the total force on a c in the direction of o x is — Fa c and the whole
force on b c is Pb c. Q and G are similarly related, so that —

— Fac = Pbc = Pac cos <v.

Gac = — Qab = — Qac sin !>, ■

or —

— F=Pcos <'/; G = — Qsin &.

*In at least some treatises on elasticity and geological mechanics it seems to have been assumed
that these planes do coincide.

FORCES IN A SHEAR. 37

The position of the plane remaining" constant, it is permissible to com-
bine J57 and G like simple forces to a. tangential component, T, acting in
the direction of a c, and a normal component. iV, acting- perpendicularly
across ac. Evidently, if P and Q are considered as in general positive

quantities —

T= — Fs!n 9 — G cos 9 = (P-f- Q) sin 9 cos ■>.
N= —Fcos 9 — G sin 9 = P cos' 9 -| Q sin' 9,

and T will be a maximum with reference to 9 when —

cos2 9 = sm2 -V or 9 = ± 45°.

Although the tangential stress is greatest for this angle, one has no
right to infer that the maximum tangential strain is at 45°, because there
is a normal stress on the plane at this angle amounting to (P-f Q) '-■
On the contrary, it was shown above (page 34) that the maximum tan-
gential strain in a shear occurs for planes which make an angle with ox
the tangent of which is 1 H. or the normal to which is given by tan 9 = a.
The conditions of this plane are also such that there can be no normal
stress acting upon it, and hence N= 0, so that one of the stresses must
have a negative value and — ■

tan? 9 =

Q

This relation enables one to determine the forces which produce a
finite shear. The area on which the stress Q acts is a, and the force
acting on the distorted cube in this direction is minus Q a. The area on
which P acts is 1/a, and the lateral force is therefore P/« ; hut by the last
equation — Qa = Pja, so that a finite shear, as well as an infinitesimal
one. results from the action of two equal forces acting at right angles to
one another in opposite senses.*

Simple Pressure. — -Knowing the composition of a shear enables one to
pass synthetically to the case of simple pressure or traction. If two
equal shears at right angles to one another are combined, the contractile
axes coinciding, each mu3t produce the same effect as the other if the
mass is isotropic. Each must also produce the same effect as if it acted
alone. This statement does not imply a relation between stress and
strain, for the shear in the xy plane leaves the mass unstrained in the
y : plane. Hence two equal shears, each of ratio «, reduce the unit cube

* I have met with no demonstration of this relation between finite shearing stress and strain, bul
I am not prepared to state that none has been published.

38 G. F. BECKER FINITE STRAIN IN ROOKS.

to a thickness l/«2 any of the sides of the mass having a length a. The
upper surface has an area «2 and the side an area, 1/a.

The tensile stress on sides of the mass is /' in each direction, so that
the two tensile forces are each Pja. When only one shear acted on the
mass the contractile stress was Q, but the second shear increased each'
unit area to «, so that the contractile stress of the first shear was thereby
reduced to Q J a. The stress due to the second shear is of precisely the
same amount, so that the total contractile stress becomes 2 Q/aonan
area «2. Thus the total force acting on this surface is 2 Qa} which, as
has heen shown, is equal to 2 Pja in absolute value.

Let the mass thus strained he subjected to an hydrostatic pressure equal
to PI a. Then the tensile forces would be balanced and the pressure on
the upper, surface would become 3 Q a.

Thus, two equal shears combined with an hydrostatic pressure equal
to either component of either shear, applied to the unit cube, reduce to
a simple pressure acting on one surface of the cube. Had the shears
been so combined that their tensile axes coincided, a dilational stress
equal to either component of either shear would have been needful to
reduce the system to a simple traction.

Conversely, it is evident that a finite traction or pressure is resoluble
into a dilational stress (positive or negative) and two shearing stresses,
just one-third of the force being employed in each of the three component
stresses. It is well known that precisely this resolution takes place for
infinitesimal tractions, but the analysis of such tractions is usually stated
as if the conclusions were true only for the limiting case of infinitesimal
forces.

These results seem to exhaust what can be known of the relations of
finite stress and strain without a further knowledge of the actual value
of a in terms of Q. No two different pressures or different shears or dila-
tions can be compared without a law relating to stress and strain.

Meaning of Hooke's Law. — It was to fill this gap that the famous law of
Hooke was proposed. This is Ut tensio sic vis, which is now translated,
Strain is proportional to stress. The brevity of Hooke's law has often
been admired. The fact is that it is too brief folly to express the mean-
ing really attached to it. It does not appear in this form of the law
whether the stress (or pressure per unit area) is to be reckoned for the
solid in an unstrained state or after the mass bus reached a condition of
equilibrium under the action of the external forces tending to deform it.
But since the purpose of the mathematical theory of elasticity is to find
equations expressing equilibrium of elastic masses, it is clear that this
equilibrium must be supposed established before one can reason on the
system of stresses which will maintain it, As a matter of fact, the lunda-

hooke's law. 39

mental equations are always derived in this way. and the stress is taken
primarily as the force per unit area of the mass in a state of equilibrium.
Tims, a less ambiguous statement of this law would be: Stress in an
elastic mass which has reached a condition of equilibrium is proportional
to the strain which the mass has undergone.

It is a curious fact that this is not the law which Hooke intended to
express. Hooke's words arc " JJt tensio sic vis: That is, the Power of any
Spring is in the same proportion with the tension thereof: That is, if one
power stretch or bend it one space, two will bend it two, and three will
bend it three, and so forward."* Thus Hooke's law as he meant it is
clearly load is proportional to strain, and he had no idea of confining his
law to infinitesimal deformations.

When the stresses and strains are infinitesimal it is easy to show that
the two assertions, stress is proportional to strain and loadis proportional
to .-train, are really equivalent : but for finite deformations they lead to
very different results.

Let a unit cube he extended to a length 1 + e by a load L, and let the
reduced area of the cross-section he J. Then the tension per unit area
or the stress P is given by —

L = AP,

and if stress is proportional to strain,

p= Me, or L = AMe,

where M is the constant, called Young's modulus and sometimes (though*
improperly) the modulus of elasticity. As was shown above, exactly
one-third of the load is-employed in producing dilation, however great
L may he. Hence if/.' is the modulus of compressibility, the volume of
the distorted cube is 1 /. '■'> !:. The volume is also the area of the dis-
torted mass multiplied by its length, or J. (1 + e). Thus —

, 1 + LIB /■

Substituting this value in the last equation gives an equation between
Load and strain, viz :

L — Me + Le 3 k ~ M = 0,
■ > fc

♦ Quoted by P. G. Tait, " Properties of Matter," 1890, p. 204, from Hooke's lectures " de Potentia
Restitutiva."

VII— Bum,. Gkol. Soc. Am., Vot. 4, 1892.

40 G.F.BECKER — FINITE STRAIN IN" ROCKS.

which is ;ui hyperbola in L and e asymptotic to

■ , and L

::/.•--. 1/" :\I,-M

Thus the fundamental assumption really made in the theory of elas-
ticity is thai the load-strain curve is an hyperbola instead of the straight
line which Hooke supposed to represenl the relation. The difference,
however, as already remarked, is without consequence, so Long as de-
ductions from it are confined to very minute deformations/-

Stress System. — Any force acting on one face of a cube may be resolved
into a normal component and two tangential components acting in the
directions of the edges of the face. Hence the most general system of
forces of constant direction acting on a cube is resoluble into six normal
components and twelve tangential ones. If the center of inertia of the
cube is at rest, the normal forces on opposite faces must be equal, and

*Naturt of tin' Proof of Hooke's Liw. — Hooke's law holds good, or, in other words, there ia a linear
relation involving a finite parameter betwe ra sm ill str - - and strains, provided — train

curve fulfills two conditions, viz.. that the curve is continuous both in form and value, and that the
tangent of the angle which it makes with the axes at the origin is finite. Ii seems to me that
some discussion and even some confusion would have been avoided if -elasticians had taken this
u lometrieal view of the functions rather than a purely alg bi deal one. Thus Green simply
assumed that the stress-strain function was developable, and that the development contained i
term in which only the first power of the variable appeared, while < lebsch seems to have lool

upon this algebraical relation as a mathematical n ssity. This it certainly is not, for there are

many continuous functions the development of which contains no term in the first power of the
variable. These all represent curves which coincide with one of the axes at the origin : e. g . the
hyperbola referred to the vertex as origin.— Mr J. W. [bbetson, in his excellent Mathematical
Theorj of Elasticity, makes an attempt to demonstrate Hooke's law by pure reason, independently
8f experiment, tie expressly assumes, however, that the eurvi is i luous, and he states,

without any atl imp! al pi th I i i ite of • n i ition of any traction component with any strain

rdinal -can never change sign or vanish. '1'his last is equivalent to asserting that the curve

cannot coincide with either axis at the origin. These two assumptions tog ther cover the whole
ground of Hools i's law, and really leave nothing to be | I 5aint-Venant, in his edition of

Clebsch, p. 10, attempted to show thai if the internal stresses of an elastic mass depend in any

it in i mas manner on the mutual distances of the molecules, Hooke's law follows. He points out

thai continuity involves a linear relation between the differentials of a function and th

differentials of any variable. He then sho on the assumption mad - corresponding small

and strains are corresponding differentials, and deduces the conclusion stated above.
This arg«menl does nol sa al all, for though one maj undoubtedly wri =Adx,

when- A is con i 'iii md tl on is therefore linear, yet A may have and often do !S have the

valu iro or infinity. Saint-A maul made no attempt in the passage referred to to show that I
must !"■ finite in the case of elastic strains, and seems to have overlooked the necessity for such a
proof,
[n the ime work, ] elastician forcibly remarks : "Generally and philosophically

no purely mathematical consid I the mer in which thi ictingonthe

elements of a bodj an I th ■ ■< mges which they produce depend upon one another."

Experiment alon md o ily somewhat refined experiment, betr 13 - the I i i thai even the h ir lesl
substance? yield somew hat to the smallest pressures, and that the stress-strain curve is con t inn
in form as well as value from positive to negative strains. One set of experiments is needful

how th i • I itl ud of a steel bar which is clamped at the i listorts it, and

other set is re [tiired to shew that the distortion is of the 9am • absolute amo tnl whether the tly
settles on the upper or the lower end id' the i,

GENERAL STRESS SYSTEM.

41

the twelve tangential forces must consist of six couples, each tending to
produce rotation.

In this paper consideration is confined to those cases in which there is
a tendency to rotation only about the line o t, and this limitation elimi-
nates four of the couples. Thus the case to be considered here consists
of three pairs of normal forces and two unequal couples tending to pro-
duce rotation in opposite directions. This force system is shown in the
following diagram :

&

-"

■ p *-

1

R ^

1

"l

<:

— c

1 1

J

-c' -*.

'

->c,

-*T

Figure i. — System of Forces.

It has already been shown that any normal force, whether finite or
infinitesimal, is resoluble into a dilation and two shears, exactly one-
third of the force producing dilation, and the remainder producing two
equal shears at right angles to one another. Analyzing each of the nor-
mal forces P, Q, R separately, it will appear that the action of all of them
may be tabulated as two shearing stresses and a dilation— thus :

Axes of .'■ >i :

Dilation
Shear . .
Shear . .

Sum . . .

':!/'+ Q+ R)

KQ + R-2P)

0

'; IP+Q + R)

}(Q+ R — 2P)
I (Q+ P — 2R)

i(P+ Q+ R)

0
HQ + -P-2 R)

Q

i;

Turning now to the coiiples <\ and C2, and supposing Qx > C!,, their
combination is equivalent to two equal and opposite couples, each equal

42 G.P.BECKER — FINITE STRAIN IN ROCKSi

to (.[. and a single unbalanced couple, C\ — < ',. The combination of two
equal and opposed couples is easily shown to be equivalent to a shear, the
axes of which bisecl the angles made by the component forces.* Here,
therefore, the balanced couples arc equal to a shear at 45° to Por Q.

There now remains a single unbalanced couple tending \<j produce
rotation of the mass about o z. Unless still other external forces are in-
troduced, this couple will merely rotate the mass without strain. If.
however, one ol the faces of the cube is compelled to coincide with a
fixed plane having the same direction as the forces of the couple,'ag
the mass rested on or against an inflexible frictionless support, this
couple, together with the resistance, will effect distortion and will convert
the square section on the xy plane into a, rhomb with two of it- sides
parallel to the fixed plane. The distortion thus produced will consist
merely in a tangential shifting of planes parallel to the support and will
involve no change of volume. In short, the strain is shearing motion or
scission.

Xo system of forces of constant direction and constant intensity will
produce scission. The combination of a couple and an inflexible resist-
ance is equivalent to a stress system like that of a simple shear, hut
which undergoes rotation relatively to the fixed axes of reference during
strain. The dynamic origin of a scission thus differs essentially from
that of a shear.

If a cube resting upon an inflexible support coinciding in direction
with "./-were subjected to the force system of figure 4. the couple '
would he inoperative and the stress system would reduce to dilation.
axial shears, and the rotational shearing stress which produce- - iission.
This last may he called scissive stress.

No support is absolutely inflexible, and in real cases of supported
masses the strains produced will he of a character intermediate between
those produced when there is no support and when the support is ideally
rigid. Such strains evidently involve both scission and a shear at 45°
to the axes.

On the whole, then, the entire force system, including a resistance to
rotation, produces a dilation, a shear in the y z plane, two -hears in the
.'■ y plane, one of them at 45° to the axe-, and a shearing motion in the .<• j,
plane. Idle most general strain discussed in preceding page- corresponds
to any combination of these strains, each of which has been treated in
detail. It has also been shown that a general strain of the type here
treated i< resoluble into just these components.

- ie an elementary proof of this proposition in Hull. Geol. Soc. int., vol. 2, 1891, p. 55.

GENERAL STRESS SYSTEM. 43

LINES OF UNALTERED DIRECTION.

It was shown above that, in general, three diameters of the strain ellip-
soid have the same direction after strain as before strain.* It is usual
to assume that these same lines retain their direction during tbe process
of strain,f but this appears to be true only under certain limitations.

If the displacements a and b are connected by the equation a = mb;
formula (7), which assigns the position of the lines of unchanged direc-
tion in the x y plane, becomes :

f—e

nK(W

and the position of the axes of the principal ellipse at the inception of
strain is given by —

&•*

tan 1 v0 — ! — f— .

e—j

1 fence one may write-

in -flf ,n ,'4 hi . ,., 0 )

tan , _ t_ | cot 1 .„ ± yj^^-^, + cot- 1 ». | .

In this formula vQ depends solely upon the direction of the external
force relatively to the resistance and not upon its intensity. Conse-
quently, if the tan * is to preserve its initial values throughout the strain-
ing process, m must be constant. Now, the displacements may lie such
that a or b is zero throughout deformation, and m is then constantly zero
or infinity. It may also happen that a = b, so that m = 1 . and this case
also involves no hypothesis as to a relation between stress and strain in
homogeneous matter; but if m is a finite quantity differing from unity,
the assumption that m is constant is equivalent to the hypothesis that
the ratio of the displacements bears a constant relation to the ratio of the
stress components which produce them. This hypothesis is only justifi-
able when the strain is very small.

When there is no rotation, or when a = b, the elastic cube acts as if it
rested upon. an inflexible support and were affected by stresses axially
disposed. When one of the displacements a or b disappears, the strain
involves only axial deformations and scission. This again implies the
presence of an inflexible support or an equivalent rotating system of
forces. Hence the lines which have the same direction after strain as

* Two of these diameters may < <>i n<- 1< l<- and both of these may become imaginary.

f Thomson and Tait speak of these lines as unaltered indirect! luring the change of straii

they may have meant by rather than during. Nat. Phil., section 181.

44 G. P. BECKER — FINITE STRAIN IX ROCKS.

belo re strain will keep this direction during strain only when the mass
acts as if it rested on or against an inflexible support.
1 f this support is parallel to o x, either tan x = 0 or :

tan y. =llZJ = tan (90° -f 2 x0).

Properties of Matter.

Viscosity. — The ideal elastic substance is one which requires a perfectly
difinite stress to hold it permanently in any given state of strain at a
given temperature. This stress is wholly independent of previous states
of strain or rates of straining. Heal substances fulfill this definition only
under certain conditions, and careful experiments always show that the
more rapidly deformation is produced, the greater is the resistance to be
overcome. Thus a spring, suddenly stretched by a given weight, yields
rapidly to a certain extent and may seem to become stationary ; but
careful observation shows that is continues to yield slowly to the traction
for a time, though it ultimately comes to rest. If the material were
ideally elastic, it would immediately assume this ultimate state of strain-
and the fact that the attainment of equilibrium is gradual proves that
the original resistance is a function of the rate of deformation. Fluids
show similar phenomena.

Viscosity is that property in virtue of which matter presents to stress
a resistance into which the rate of deformation enters as a factor.
Viscosity and shear are inseparable, and mere dilation is unattended by
viscous phenomena* The coefficient of viscosity of a substance is ceteris
paribus, the shearing stress required to produce the unit shear in the unit
time. The degree of viscosity is considered as increasing with this coeffi-
cient, so that sealing wax and tar are more viscous than water, and steel
is more viscous than lead or copper.

Substances which yield indefinitely though slowly to stresses, however
small, are now known as viscous fluids. Those which in the course of
time reach statical equilibrium under the action of deforming stress, such
as tallow and steel, are called viscous solids.

If stress is applied very slowly (or rather infinitely slowly) viscosity
does not come into play. Thus, a viscous solid or fluid in permanent

* Viscous resistance is often likened to friction. Each is a dissipative resistance to tangential
motion, but there are marked differences between them. Friction exists only where there is
normal pressure, and is therefore wholly absent on the planes of maximum tangential strain in a
shear. Friction also has its maximum value when the surfaces between which it exists are at rest.
Viscous resistance opposes relative motion of surfaces between which there is no normal pressure
when the rate of motion is finite, bul vanishes when this rate is infinitesimal. Thus their is
rather an analog} than a similarity between viscosity and friction.

VISCOSITY. 45

statical equilibrium acts like an ideally clastic or ideally fluid mass.
Under these conditions the resistance winch a solid offers to deformation
is due entirely to its "rigidity," this term being defined in the theory of
elasticity as the degree of resistance winch a solid in permanent equi-
librium opposes to stresses tending to change its shape* Under this
definition india-rubber and tallow possess rigidity as well as cast iron,
but the modulus of rigidity of the metal is greater than that of the gum
or the tat. In short, rigidity is an essential property of solids.

A highly viscous fluid subjected to a stress of brief duration presents
greal resistance to deformation. Thus, if the earth were substantially a
mass of sufficiently ultra-viscous fluids, it would behave to the attrac-
tions of the sun and moon sensibly like an infinitely rigid body, because
of the rapid change in the direction of these attractions. There are valid
grounds, however, tor the belief that the earth is really solid.

The viscosity of rocks often controls the directions in which they yield
to stress. When two equal stresses acting on the same rock-mass change
their directions at different rates, that stress which rotates at the smaller
rate will encounter the smaller resistance and will produce the greater
effect, It has been shown in the earlier part of this paper that all rota-
tional strains are accompanied by relative tangential motion on two sets
of mathematical planes which rotate relatively to the mass at different
rates. The difference of their effects due to viscosity will be discussed
under the head of geological applications.

Flow. — At least some solids in the so-called "stale of ease " (freedom
from internal partial constraint) almost completely recover their original
form after small strains when time is allowed to overcome the viscosity.
It is apparently true of all bodies, however, that when strained beyond
a certain limit short of rupture, they are permanently deformed. The
process by which this deformation is effected is termed flow, and the
limit at which a, substance initially in a state of ease begins to flow is
called the limit of solidity. When the limit of solidity differs hut little
from tin; ultimate strength, the substance is known as brittle. When
the limit of solidity is a fixed quantity, so that any excess of stress pro-
duces continuous flow, the mass is said to be plastic. When a continu-
ously increasing stress is needful to produce continuous How, the sub-
stance is said to be ductile, and in this case a " hardening " of the mass
attends the flow, as. for example, in the manufacture of wire.

Plastic flow thus differs from ductile flow. 1 am not aware of any
phenomena which point decisively to. the existence of ductility and the
attendant hardening among rock masses, but it cannot he amiss to call

*The word rigidity, as used in the theory of elasticity, lias nearly the same aning as stiffness

in common parlance.

1(> G. F. BECKER— FINITE STRAIN TX ROCKS.

attention to this property, which possibly plays some pari in the interior
of the earth if not near the surface.

Plastic flow certainly plays an important part in geological mechanics-
The motion of glaciers is known to be in part ascribable to it. and it is
clearly evinced in the details of rock structure. At greal depths below
the surface a partial gradual relict' of strain in any rock mass will bring
to bearagrad.ua! increase of stress difference, which may be considered
entirely indefinite in amount. Granting, then, that there is no infinitely
brittle rock or no rock in which the ultimate strength tails short of the
limit of solidity, flow must ensue at great depths whenever a sufficient
relief of strain occurs. No geologist need- to be reminded of the instances
pointing to such flow. They are innumerable and most various.

If a mass capable of plastic flow is suddenly subjected to ;i definite
load greater than it can hear without flowing, one-third of the load will
immediately he employed in compression and the process of flow will
produce no further modification of the volume. Flow is thus continuous
shear.

The shearing process must take place along certain lines, and these
must he the lines which are first strained beyond the limit of solidity.
In other word-, flow must take place along the lines of maximum tan-
gential strain discussed in a former part of this paper. ami which by I 10)
stand at an angle 90° — <» to the line of a simple, direct pressure. When
the load is of fixed amount, the stress will gradually diminish as the mass
flattens out; so that the last lines of How will make a smaller angle with
the line of force than the earlier ones. A greater amount of flow would
occur along the earliest lines affected. If the mass were of such a char-
acter as to show evidences of the relative motion after equilibrium had
been reached, a cross-section of it would reveal a structure at Least com-
parable with schistosity. the flatter lines being more pronounced than
the steeper ones.

Relation of plastic Solids to Fluids. — Let S he the resistance which a
plastic solid opposes to distorting stress at the elastic limit, and let u he
the stress which would he required to produce the unit shear it' the mass
were perfectly elastic (or, in other words, the modulus of rigidity); then
if stress is proportional to strain. S/n is the shearing strain which the
mass experiences at the elastic limit, and any greater -train would be
accompanied by flow. If the mass continues to How as long as the stress
is maintained above the fixed limit S/n, the substance is known as per-
fectly plastic.

If S is infinitesimal, the mass will yield to any shearing stress, however
small. Such a mass, resting on a level surface, would spread out to a
layer of infinitesimal thickness, much like a fluid. It does not follow.

PLASTIC SOLIDS.

47

however, that because S is very small, n is also small. The rigidity of a
mass seems quite independent of its elastic limit. Tims wrought iron
and cast steel have nearly the same modulus of rigidity, though the
elastic limit is very different for the two substances. A material, then,
may have a very low elastic limit and yet oppose great resistance to de-
formation within that limit.

If the rigidity of a mass is great, the lines of maximum tangential
strain under pressure will make angles of little more than 45° with the
line of pressure. If such a mass is prevented from undergoing relative
motion in these directions, a much greater force will he necessary to com-
pel it to move in any other direction. Fancy a cube of matter of low
elastic limit, but great rigidity, placed in a shallow tray just wide enough
to receive it; and let a small, uniformly distributed pressure be applied
to the upper surface of the cube. Then, above the edge of the tray, the
mass would break down at angles of about 45°, but the lamina' standing

Figure 5. — Plastic Solid under Pressure.

at 4o° and supported by the tray could not move sensibly. The result
would be that a pyramidal mass would remain in the tray, forming an
angle of 45° with the line of pressure.

This is substantially the way in which a body of solid, discrete parti-
cles would act. A cube of such material released in a, tray would resolve
itself into a pyramid, sloping at the angle of rest. It is also easy to show
that the maximum value of this angle is 45°.* A mass of very tine
powder composed of frictionless spheres would be perfectly plastic, inas-
much as it would yield to any shearing stress, however slight, which
were not resisted by external constraint. The elastic limit would also be
zero. Its rigidity could be displayed only when flow were prevented by
constraint in the direction in which flow tends to take place. It would
then evince rigidity by its ability to retain a pyramidal shape. In short,
a mas-; resembling shot of infinite fineness appears to represent the case
of a perfectly plastic solid with infinitesimal elastic limit.

*The angle of rest is, say, p, and tan p = S/ N, where N is the normal pressure, and R the fric
tional resistance due to'this pressure. This resistance cannot exceed the pi — ure to which it is
due, and B - A cannot exceed 1, tli<- tangent of 15 -

VIII— Bui.t.. Geol. Soc. Am., Vol. -1, KS92.

48 G. F. BECKER FINITE STRAIN IN ROCKS.

Consider now the case in which n is very small and S great. This case
also bears some resemblance to a fluid. A cube of material with these
qualities would yield to the slightest pressure, and the strain ellipsoids
would be flattened to infinitely thin disks. The lines of maximum tan-
gential strain would therefore be perpendicular to the line of pressure.
To convert this solid into a liquid the elastic limit and the rigidity must
both disappear; but this is not of itself sufficient. The flow of a liquid
takes place perpendicularly to the direction of pressure; consequently,
in the solid which approaches infinitely near to the liquid state, the
strain ellipsoids must be infinitely flattened before flow begins. This
relation is secured if S is infinitesimal and n is an infinitesimal of the
second order.

In the discussion of strains it was shown that the lines of maximum
tangential strain, or the lines on which flow must take place, make an
angle with o x, which has a certain value, m. It appears from the above
that this angle has a value of 45° for an infinitely rigid solid, even if this
solid is perfectly plastic and has no elastic limit, so that it is reduced to
molecular powder. For fluids, on the other hand, this angle is zero, and
the rigidity is an infinitesimal of the second order. Intermediate values
of m answer to solids of moderate rigidity.

Rupture. — In a homogeneous mass under pressure, rupture must take
place on the lines of maximum tangential strain: for rupture is strain
carried to such an intensity that cohesion is overcome. A mass in which
flow has preceded rupture cannot be regarded as homogeneous, since in
the direction in which flow occurs the strength of the mass may be and
perhaps must be weakened. In the case of pressure this makes no dif-
ference, the tendency to flow and to rupture being in the same direction.

Tensile stresses produce ruptures by a different method. One can
conceive of a mass breaking up by mere dilation or without any relative
tangential motion, while purely compressive forces cannot be imagined
as leading to rupture. In tensile strains shears cooperate with dilation.
Thus, if a bar under tension is homogeneous, the tension will be relieve. 1
by the smallest possible fracture, which is in a direction perpendicular
to the axis of the bar. If, however, the bar has undergone flow along
the surfaces of maximum tangential strain and has thus been sensibly
weakened in these directions, it may split diagonally to the axis or
irregularly along some other path of least resistance. Thus, a rubber
band when suddenly stretched almost always breaks as straight across
as if cut with scissors, but a bar of mild steel gradually stretched to the
breaking point often splits diagonally, while a wooden bar gives a most
irregular surface of fracture.

In rocks, tensile rupture and fracture by pressure can often be distin-

RUPTURE. 49

guished. Granites, and even conglomerates, often break under pressure
in extraordinarily smooth, continuous, plane surfaces. Under tension
the rupture of granite would follow an irregular surface of least resist-
ance, leaving projecting crystals on each side ; and in conglomerates few
pebbles would be broken, nearly every one adhering either to one frag-
ment or the other. Stratified rocks under tension would behave much
like a wooden bar. Only unusually uniform rocks could give smooth
surfaces of rupture under tension. Such surfaces do occur in the case of
columnar eruptives, and these columns can be shown to be produced by
tension in the cooling mass. Even when tension produces surfaces of
rupture which are smooth, they are apt to be curved or broken. In a
word, tension tears masses asunder; pressure cuts them to pieces.

Geological Applications.

Cases to be considered. — It is probable that pure dilation and pure irro-
tational shear are strains of rare occurrence in rock masses. One of these
requires two, the other three pairs of forces acting at right angles to one
another with identical intensity. Simple pressure, on the other hand, is
common, especially where disturbances are not in progress. During
orogenic changes inclined pressures must be frequent. The most im-
portant stress systems are therefore direct pressures and inclined press-
ures. The last includes two cases, in one of which the mass suffering
pressure rests upon or against an unyielding support, while in the other
the mass rests upon or against materials which yield readily. In the
former of these cases the stress system reduces to a simple pressure, com-
pounded with a scissive stress ; in the latter to a pressure and a shearing
stress.

In dealing with each strain viscosity and a tendency to How or rupture
must be considered, the aim being to relate actual phenomena to their
immediate causes and to enable the geologist, in some measure at least,
to judge of the local direction of the forces the effects of which he observes.

When gravity acts noon a mass homogeneous strain is. strictly speak-
ing, impossible, excepting within infinitesimal limits of space, each level
surface being subjected to greater pressure than the next above it. On
the other hand, the forces involved in the deformation and fracture of
rocks are very great, except in some extreme instances, such as that of
moist clay. For ordinary firm rocks the ultimate strength is such that
a column of from one to several thousand feet in height would be needful
to produce at its base a pressure sufficient to induce rupture. Conse-
quently,in masses of such material from a few score of feet to n lew hun-
dred feet in thickness, gravity plays but a small part compared with

50 G. F. BECKER — FINITE STRAIN IN ROCKS.

rupturing stress ; and portions of the rock having dimensions of this order
may often properly be regarded as homogeneously stressed. When large
masses are similarly strained, gravity may determine in which of several
directions, all equally stressed by external pressure, rupture will take
place. Cases of such determination 1 have discussed in a formerpaper*

Effects of direct Pressure. — A direct, uniformly distributee1 pressure of
sufficient intensity, applied to an elastic brittle mass presenting great re-
sistance to deformation, would induce fracture. The ruptures would take
place along those lines subject to the greatest tangential strain, since
these are the directions in which the material would first be strained
beyond endurance. These lines would stand at 45° to the line of force
if the mass presented infinite resistance to deformation. If this resist-
ance is not infinite, they will stand at greater angles to the line of force.
The angle which the normal to the direction of rupture makes .with the
line of force is called w in the discussion of the strains (see p. 34).

There will generally be more than one direction of rupture, and in
masses the thickness of which in the direction of pressure is considerably
smaller than the lateral extension, there will often be four systems of
parallel fissures, two systems answering to each of the two equal shears
arising from simple pressure. If, however, there is any inequality of re-
sistance in the plane perpendicular to the line of pressure, whether this
is due to the character of the mass under pressure or to inequalities in
the support which this mass receives from its surroundings, the strain
ellipsoid will have three unequal axes, and rupture will take place only
in the plane of the greatest and the least of these axes. In this very
common case the mass will be divided into columns, with angles de-
pending upon the strain. "When the mass is large and the pressure is
horizontal, gravity opposes the tendency of the vertical axis of the strain
ellipsoid to elongate, and rupture will tend to take place by relative
motion in horizontal planes, separating the rock into vertical columns.
The constraint of surrounding masses may outweigh this tendency.

Something can be said of the spacing of the fissures thus formed, but
this subject can be most conveniently discussed under the head of in-
clined pressure.

If the pressure continues alter rupture has occurred, the Mocks or
columns will grind against one another producing slickensideSj and
sometimes further ruptures, of which the discussion will also be deferred.

Many rocks under the action of direct pressures rapidly applied behave
approximately as highly elastic brittle masses of greal rigidity, and in
these cases the range of the planes of maximum strain is practically nil.
Consequently, systems of fissures at sensibly right angles to one another

♦Bull. Geol. Soc. Am., vol. 2, 1891, p. 62.

SIMPLE DIRECT PRESSURE. 51

are not infrequent, nor js it very unusual to find such a pair of systems of
fissures accompanied by a second similar pair in a plane at right angles
to the first. The residual blocks are then bounded by from four to eight
planes. In the last case four of the planes are parallel to the other four *

In many cases the rock does not rupture without previous deforma-
tion of considerable amount. When this happens the lines of rupture
make an angle of nTore than 45° with the line of force. The normal to
the direction of rupture then makes an angle w with the line of force,
and this angle decreases with the deformation. If the deformation were
very great,as it would be with a mass of india-rubber, u> would approach
zero. If the direct pressure were relieved by rupture and the rock were
perfectly elastic, the residual fragments would recover their original
shape, and their acute angles would then lie in the line offeree.

Thus when rocks show fissures cutting one another at acute angles
it is certain that finite deformation has taken place. If the mass has
remained under tension, the line of force when direct bisects the obtuse
angles. If the mass has been relieved of pressure and the rocks have
acted as elastic masses, the line of force bisects the acute angles.

It is usually possible from general conditions to judge which of two
rectangular directions is the more probably that from which a rupturing
force has acted. I have, however, never yet met an instance in which it
seemed to me that the line of force bisected the acute angles" of fissure
systems. Orogenic forces are commonly very persistent, and even if a
mass behaved as substantially elastic up to the moment of rupture, it is
improbable that the residual blocks would continue capable of regaining
their original shape after the lapse of, say, even a few years. In many
cases it is quite clear that deformation has become permanent. Thus I
have examined very numerous pebbles in conglomerates, some of which
had been much flattened by pressure and others also much fractured.
The direction of flattening was then a certain indication of the direction
of force, and this direction bisected the obtuse angles between the fissure
systems intersecting the pebbles. In other cases the character of slicken-
sides and accompanying faults shows that no reversal of motion has
taken place, and that the residual masses must have lost the elasticity
which they seem to have exhibited up to the moment of rupture.

Observations on artificial structures seem to confirm this opinion. It
lias been pointed out by Mr. Clarence; King aim1 others that slabs of
marble supported at their ends or corners gradually sag toward the
center. So, too, in old buildings, such as the Alhamhra, 1 have seen
slabs of rock very much bent by c\m\ pressures acting for hundreds of

* When a rock fragment is lioun.li> I by planes \\ ith more than lour differently directed normals,
it must have undergone successive ruptures

52 G. F. BECKER FINITE STRAIN IN ROCKS.

years. This does not imply that there is no true elastic limit, but only
that it is lower than brief laboratory experiments would lead one to
suppose. Were there no elastic limit, it seems to me that we should
find, for example, quartz crystals in vugs among the more ancient rocks
sensibly distorted by their own weight.

Usually then the line of a simple, direct pressure which has produced
two or four systems of fractures in large rock masses, or in the pebbles
of conglomerates, will he found to bisect the obtuse angles between the
fissures as the mass now stands. In any case, where it is suspected that
the line of force bisects the acute angles between fissures, the slickensides
should be minutely examined to ascertain whether they show reversal of
motion, and all the attendant phenomena should be investigated.

When a simple pressure on a rock mass increases very gradually, it
will for some period exceed the elastic limit of the rock and fall short of
the ultimate strength. Flow must then take place. The only feature of
this flow which will reveal itself to observation will lie the relative move-
ments of adjoining particles. Hence, although the path in space of each
particle will lie hyperbolic,* the evidence of movement will indicate rela-
tive transfer of adjoining particles in opposite directions along lines of
maximum tangential strain. The energy of this relative movement will
evidently increase with the excess of the pressure above the limit at which
flow begins, sometimes called the limit of solidity.

Thus, if one supposes the pressure suddenly to surpass the limit of
solidity and then to be kept constant, the mechanical effects of the rela-
tive motion (and the chemical effects attending the expenditure of energy)
will be very pronounced on the lines on which flow begins. As the pro-
cess continues and the stress diminishes with the increase of the area of
the mass, the lines first affected will make an increasing angle with the
line of force, while the new fibers of the material which are forced into
the direction of maximum strain will be less and less affected.

The result will at least resemble schistose structure and will be marked
by the presence of lines of relative movement intersecting one another at
very acute angles. In the case of direct uniform pressure there will be
four such sets, each set at a large angle to all the others.

If the load were to increase in the same proportion as the area of the
loaded mass, so that the stress would be kept uniform, an indefinite
amount of flow might be produced, provided that the rock is not hardened

♦During flow there, is no progressive change of volume. Hence, a point for which at the incep-
tion of flow x = 1, y = 1, will be moved to a point x', i/, and .<■"- y' — 1. The curves of this form are
sometimes called the lines of flow They would be more aptly called lines of absolute movement.
They should carefully hi' discriminated from the lines of relative movement, which are straight.
The hitler are the only ones of which the deformed mass can give direct evidence. 1 n i he case of
simple shear the lines of absolute movement are simple hyperbolas asymptotic to the axes.

ARRANGEMENT OF PEBBLES BY WATER. 53

like drawn wire. If the Aoav were very great (literally infinite) the lines
along which relative movement took place at the inception of strain
would become horizontal. The schistose partings would then in each set
range through the %ngle «>.

Relative motion, in a mass subjected to direct uniformly distributed
pressure, can only take place perpendicularly to the line of pressure when
the strain ellipsoids are infinitely thin discs or when the rigidity is zero.
In other words, only liquids, viscous or otherwise, can act in this manner.
The behavior of semi-fluid material, like wet clay, approximates closely
to that of a viscous fluid.

Rigid Disc in rcxixliiHj Medium. — The behavior of an elastic mass under
simple pressure leads to an extremely simple method of proving a
dynamical proposition of much importance to geologists. A simple
pressure acting against a resistance converts any sphere of unstrained
matter into an oblate ellipsoid of revolution, the minor axis of which is
in the direction of the pressure. If the constant pressure were to exceed
the constant resistance, the mass would move in the direction of the
pressure and of the minor axis of the oblate ellipsoid. Now, it is a well-
known fact that the whole or any portion of an elastic mass which is in
equilibrium, whether at rest or in motion, may be supposed to become
infinitely rigid without disturbing the equilibrium. This is an almost
self-evident proposition, for a mass is in equilibrium only when there is
no influence tending to change its form, and it therefore makes no differ-
ence whether this form is capable of change or not. Hence in the present
case the strain ellipsoid may be supposed replaced by a rigid mass.
Consequently a rigid ellipsoid of revolution moving under the influence
of a pressure against a resistance will be in equilibrium when it opposes
its greatest surface to the resistance.

Similarly an elastic sphere under tension becomes a prolate ellipsoid,
and consequently a rigid prolate ellipsoid moving under the influence
of tension against resistance will be in equilibrium when its longest axis
coincides in direction with the tension.

If a cube were circumscribed about either of these spheres, with four
of its edges in the direction of the force, it would become a rectangular
parallelopiped with sides parallel to the axes of the ellipsoid. Any plate
or rod may be made up of a single layer or row of such flattened or
elongated cubes. Hence any rigid disc or rod moving against a resist-
ance under the influence of pressure will be in equilibrium when its
smallest dimension is in the direction of pressure. If it moves under the
influence of traction, its longest axis will fall into the line of traction.

If a flattened pebble is dropped into a running stream, the water will
exert a pressure upon the stone until its inertia is overcome, and during

54 G. F. BECKER — FINITE STRAIN IN ROCKS.

this time the pebble will tend to swing across the current so as to present
its greatest area to the pressure. As soon as the resistance duo to its
inertia is overcome, the pebble will sink through the water as if the fluid
were at rest till its edge touches the bottom, and it will then lip down
stream till it meets support. In rapid steams irregularities in the bottom
cause local upward currents, which project pebbles into the main current
much as if they had been dropped into it. These pebbles sink to the
bottom again where the movement of the water is more uniform. Many
pebbles thus deposited will, with few exceptions, be inclined down stream
and will rest against one another, like overlapping tiles.

This relation explains the fact that both in modern streams and in the
ancient river channels containing the auriferous gravels, many of which
have been tilted since their deposition, the pebbles, as miners say.
"shingle up stream," or, as zoologists would express it, "imbricate"
toward the source. Elongated, rOd-like pebbles are usually found lying
across the channel. The indication afforded by this behavior of pebbles
seems entirely trustworthy so far as the local current is concerned. In
applying it, however, it must be remembered that powerful streams arc
often accompanied near shore or close to obstructions by local " hack
currents," in which the pebbles would be arranged in a direction opposite
to that of the main stream.

If a flat pebble or a mica scale is allowed to subside in relatively quiet
water, the fluid may be considered as exerting a pressure on the lower
side against a resistance due to the action of gravity on the stone. The
disc will then tend to assume a horizontal position. It is for this reason
that allothigenetic mica scales in sandstones or other rocks usually follow
the direction of the bedding. In massive sandstones this is an assistance
in determining the true stratification.

A very familiar illustration of the action of the strain ellipsoid moving
against resistance is afforded by a bubble of gas rising through still water.
The spherical bubble is compressed to an ellipsoid, which might be re-
placed by a rigid mass of the same density, and it rises with its equator
in an almost perfectly horizontal plane.

On beaches pebbles are sometimes imbricated for a few feet in one or
another direction and sometimes lie nearly flat. The constant reversal
of the currents due to breaking and retreating waves prevents any exten-
sive methodical arrangement, and this fact is of assistance in discriminat-
ing marine gravels from river deposits.

There are also instances of the almost self-evident fact that a rod-like
mass moving under the influence of traction, like a vessel under tow, will
move end on. In glassy rocks, such as many rhyolites and andesites?
the mass often shows a handed structure, marked by the presence of

EFFECTS OF INCLINED PRESSURE. 55

microlites, most of which are parallel to the banding. Those microlites
are no doubt of greater density than the glass, but, on account of the
viscosity of the melted glass and the enormous surface per unit volume
which the microscopic prisms expose, they cannot be supposed to attain
their actual arrangement as a result of gravity like the mica scales in
sandstone. On the other hand, if one supposes an irregular orientation
of the microlites in the glass, and that tangential motion has been set up
between adjacent layers of the viscous mass, every microlite standing
across the direction of relative motion would be swung into the line of
relative motion by the opposite traction exerted on its two ends by the
moving layers. It appears to me, therefore, that " rhyolitic structure "
indicates "shearing motion " or, as I have called it, scission in the direc-
tion of the banding *

Inclined Pressure and yielding Medium. — An inclined pressure acting on
a tabular mass of rock is equivalent to a direct pressure and a tangential
force. This last, with the resistance necessary to keep the center of
inertia of the rock at rest, forms a couple. If the rock is surrounded by
masses of comparatively feeble resistance, it will then rotate until the
couple is exactly balanced 1 >y the resistance to rotation. The rock is thus
subjected to the action of a simple pressure and two balanced couples,
constituting a simple shear, neither of the axes of which coincides with
the line of pressure.

As has been shown above, the strain produced by a pressure and a
shearing stress is a rotational one, the amount of rotation, however, being
small as compared with that involved in some other strains. One of the
directions of maximum tangential strain will therefore sweep over a
greater range of material particles than the other, or will affect a given
set of particles for a shorter time. That set of planes of maximum strain
which shifts its position more rapidly will encounter greater resistance
from viscosity and will produce the smaller effect.

If the mass is strained beyond the elastic limit, but not to the point of
rupture, a schistose structure will result , but one set of schistose partings
will be confined to a somewhat smaller angle than the other and the
more pronounced partings will be associated with the smaller angle.

If the pressure is intense enough to produce rupture, fracture will take
place chiefly along the partings which have the smaller range.

The axes of the strain ellipsoid will bisect the angles which the last
schistose partings make with one another, and the minor axis of the

* The above discussion is incomplete. A full treatment would ot cour ■ i ign a definil i value to
the couple which resists the tilting of a disc moving in a fluid. The reader will find the subject
more fully developed in Thomson and Tail, Nat. Phil., sections 320-325, with interesting instances.
That discussion is decidedly difficult, while the main points in which geologists are inl iresl ■'!
seem tu be adequately demonstrated by the exceedingly elementary method here presented.

IX— Bull. Gkol. Soc. A.m., Vol. 4, 1892.

56

G. F. BECKER FINITE STRAIN IN ROCKS.

strain ellipsoid, or the direction of maximum compression, will lie
between the line of pressure and the compressive axis of the additional
shear.

When the rock is ruptured without sensible deformation the strain
under discussion will not be rotational and will be indistinguishable
from that which would result from a simple shear; for in the xy plane
one of the shears arising from direct pressure cooperates with the shear
resulting from the preliminary rotation, and their combined effect will
be greater than that of the second shear in the y z plane arising from the
direct pressure component.

The character of the finite strain is best seen by an illustration such as
that in the diagram, figure 6, A.

X\

Ftguee G. — Strained Cubes.

The dotted squares are strained to the rhombs, drawn with full lines. A results from two shears
at 45° to one another, the ratio of each shear being 5/4. B results from a shear and a scission, the
ratio of each of the two shears involved being also 5/4. The central crosses mark the direction of
the ellipse axes. The angle R is the material angle through which one set of planes of maximum
tangential strain sweeps, and r is the other corresponding angle. In A, R — r = v — ^ = 2° 45'. In
B,R — r = 15° 21'.

Inclined Pressure and unyielding Resistance. — When a tabular mass of
rock subjected to inclined pressure rests against a mass which does not
yield considerably, the free couple which results from the tangential
component of the pressure and the resistance of the supporting mass can
only be equilibrated by strain in the rock itself. The strain will then-
fore include as one component a shearing motion or scission.

This strain is rotational, the angle of rotation being far greater in this
case than in that of a yielding support. The rotation is here of the same
order as the strain. Consequently one set of planes of maximum tan-
gential strain Avill sweep through the mass much more rapidly than the
other, and the difference in their action will be very pronounced. The
nature of the distortion is seen in figure 6, B.

FISSURING BY INCLINED PRESSURE. 57

Partial Theory of the Spacing of Fissures. — When a slab of rock resting
broadside against an inflexible support ruptures under the influence of
a pressure inclined to the supporting plane, it is easy to see that the
pressure can be relieved only by several cracks, which must divide the
mass into sheets bounded by planes of maximum tangential strain.
Such a division is extremely common on a large scale in granite and
other relatively homogeneous masses ; on a small scale it is frequent in
the pebbles of conglomerates which have been subjected to pressure. It
is therefore very desirable to ascertain the conditions which determine
the thickness of the sheets.

A slab of rock must evidently rupture in such a manner as to relieve
the pressure upon it, and this relief must be accompanied by a readjust-
ment of the fragments. This consideration at once assigns a superior
limit to the spacing of the cracks. Suppose, for example, that in a case
illustrated by the following diagram cracks were to form only at a and c5
then, since a perpendicular from the upper end of a falls between a and c,

a lr c

Figure 7. — Widest possible Spacing of Fissures.

the fragment a a c c cannot rotate without increasing its vertical dimen-
sion, and the pressure cannot be in any way relieved by the ruptures.
But if a third crack, b b, is so placed that its lower end is perpendicularly
below the upper end of a, the fragment a a b b can be rotated so as to
decrease the vertical dimension, and thus to relieve pressure. Hence
the cracks must be at least so near to one another that the terminations
of adjacent cracks are in vertical lines, and the higher the angle which
the cracks make with the fixed plane, the nearer must they be to one
another. This, however, is an extreme case; for an infinitesimal rota-
tion of the vertical line a b about any point of it would not diminish the
thickness of the mass. The actual distance between fissures must there-
fore be less than that assigned by this limit.

When the process of straining is so slow that the mass can fully adjust
itself at each instant to the external forces (an important limitation) it
seems impossible to avoid the conclusion that the actual spacing will be
such as to depotentialize the greatest possible amount of energy for a
given length of fissure. In other words, the cracks will be so disposed as

58

G. F. BECKER — FINITE STRAIN IN ROCKS.

to "do the most good." If so, the spacing can he determined if one can
succeed in expressing in exact terms the depotentialization of energy per
unit length of crack.

The lines of maximum tangential strain make angles <o with the major
axis of the strain ellipse. When the strain is due to a pressure at a posi-
tive, acute angle <p with the fixed plane (parallel to o x), the major axis
makes an acute negative angle » with ox. That set of planes of maxi-
mum tangential strain which have the smaller range during the process
of strain, and upon which there is the least viscous resistance, then makes
an angle « -f- > with o x.

Let w he the thickness of one of the sheets into which rupture may
divide the slab of rock, and let # he the angle which the diagonal between
the obtuse angles of the sheet makes with o x, as indicated in the follow-
ing diagram, figure 8. Then, if the thickness of the slab at the moment
of rupture is 2 /, a little consideration shows that —

iv = 21 cos (y + <**") \ 1 — tan (y -\- to) cot # j- •

It is evident that the total length of the cracks is inversely propor-
tional to the thickness of one sheet or to w.

Figure 8.— Spacing of Fissures.

To determine the relief of pressure it is convenient to begin by con-
sidering a mere change of strain. Suppose a slab to he in equilibrium
under the action of a simple, direct pressure. Let the mass now undergo
a small change in physical properties, such that it yields by a small
additional amount to the pressure. Then the potential energy of the
system is diminished in proportion to the amount of this secondary
yielding, measured in the direction of the force. Only one fiber passing
through the center of the mass, however, will move solely in the same
direction in which the pressure acts, all other particles moving on hyper-
bolic bines.

If the pressure were inclined to the surface at an angle cr. the depoten-
tialization of energy under similar circumstances would also be measured

SPACING OF FISSURES.

50

by the movement of particles in the direction of the pressure, irrespective
of the movements which they execute in other directions.

The rupturing of the slab into sheets may be regarded as a change in
its physical properties such as is contemplated above.

f\f

1

c

^^*C~'

-s** ""' — -

— y^'

\ ^^"^ '

^s- s

s ^s

s ^^

*\-d-s ^^

r^ "" " ~Z^ "'?

^^ ' '

^^ ' i

^^ / t^*

J^*^ ^ ^*^

^s^ ' _^"^ 1

^r s ^^r ,

^ ' " — *^ i

a.

b

Figure 9.
Cut a shows'the same mass as figure 8, the sheets now being rotated through a small angle S by
the pressure acting in the direction <j>. Cut 6 represents the corner c' of one sheet on an enlarged
scale, together with the original position of this corner at c.

The line c' r is the distance measured in the direction of the force
through which the point c has moved in passing from c to c', so that c' r
is proportional to the depotentialization of energy. The angle of rotation
being small and arbitrary, say, <J, the angle cc' i = # and —

(•r) = («0

cos #
sin <p

Then, too, (cc) = (oc) 8 = 18 js'm &, so that the relief of pressure varies
with the line —

(c'r) =

18_
sin <p

cot #.

The relief of pressure per unit length of crack therefore varies with-

w

, i >. 4 I2 8 , . f 1 tan(y + ut)} <

Cc r) = — — cos 0 4- «0 i 1 — — -, — - - cot >>

sin <p ( tan * 3

and to find the distribution of fissures which will ensure the greatest

CO G. F. BECKER — FINITE STRAIN JN RUCKS.

depotentialization of energy per unit Length of crack, it is only necessary
to determine the value of #, which will give the last expression a maxi-
mum value. This problem lends at once to —

2 tan (y -f- a)== tan #,
or —

to = I cos (y + «),

a result of very convenient simplicity.

Thus far it has been assumed that only one set of fissures forms in tin-
slab. This case is of frequent occurrence in rocks, but it is not much
more frequent than the appearance of two sets of fissures forming large
angles to one another. Under conditions such that viscosity does not
essentially modify the results, there should be as great a tendency to
form fissures on the other set of planes of maximum tangential strain,
making an angle to — i> with o x, as on those planes discussed above.

When two sets of fissures form at large angles to one another they must
seemingly develop simultaneously; for. if a single set of sheets were to
form first, and secondary fissures were to be produced by the grinding of
the sheets against one another, it is easy to see that the secondary fissures
would make but a small angle with the primary divisions, and there
would be more evidence of movement on the first fissures than on the
subsidiary cracks. These cracks would also not in general pass from one
primary sheet to the next.

When the two sets of joints form simultaneously, each set must form
under similar conditions, and I can think of no reason to suppose that
they do not form independently. Hence the theory already developed
seems to apply also to the second set of fissures, the only change needful
being the substitution of to — v for m -f- '■>.

The results derivable from this theory of division certainly accord with
some well known facts. Thus, if a tough mass is acted upon by a shear-
ing tool, it is a matter of daily experience that the mass undergoes a
single cut. For this case viscosity comes into play, and by the theory
only one set of fissures will he developed, cr = 0, to -{- v — 0 and w I.
which means that only one fissure will intersect the mass. Again, it' one
attempts to cut a brittle substance like glass with a shearing engine, the
mass, according to experience, shatters instead of simply dividing. By
the theory as applied to this case the elastic deformation is extremely
small, neither set of planes of maximum tangential strain has a sensible
range, and to -J- v = 0, while to — v = 90°, nearly. Hence only a single
fissure will tend to form in the direction to -f >. but the mass will be
divided into scales of almost infinitesimal thickness in the direction
to — v. In other words, the theory substantially accounts for the facts.

EXAMPLES OF FISSTJEING. 61

In theory as in practice, only masses capable of considerable deformation
under the system of external stresses can be divided by a single clean cut.

This conclusion seems to throw some light upon a general feature of
geological fractures. In the laboratory rocks are very brittle substances,
and every geologist has experienced a feeling of surprise that in natural
rock-exposures clean cuts in a single direction are so frequent. It now
appears that cuts of this description can occur only when the stresses are
such as to produce a considerable elastic or plastic deformation of the
mass. There is, of course, abundant other evidence that such stress
systems really accompany orogenic movements.

Examples of inclined Pressure. — According to a famous theory developed
by Navier and Poisson the ideal isotropic solid is characterized by the
property that in a simple elongation of small amount the linear lateral
contraction is just one-fourth of the increment of length. Though must
elasticians refuse to acknowledge the theoretical basis of this conclusion
(viz, that the action between two molecules is reducible to a single force
acting between the centers of mass), there is no doubt that several sub-
stances, and especially glass, behave sensibly as this theory demands.
As some rocks are glasses, it is certainly legitimate to assume, for the
purpose of illustrating the theory of rupture developed above, that the
relation 1 / 4 holds true*

Let a pressure Fact upon a slab of a rock fulfilling Poisson's ideal at
an angle of 30° and let the mass rest against a rigid support. Then if
U and Q are the horizontal and vertical components —

U= — F cos 30° = —F\(^ ; Q=—F sin 30° = — C

If also n is the modulus of rigidity, it is easy to show and is well known j
that —

* Possible Test of Poisson's Hypothesis.— One of tin1 obstacles attending the discussion of Pois.-.>n'-.
solid and the question whether or not the coefficients of rigidity and compressibility for isotropic
solids are independent consists in the fact that it is difficult to determine Young's modulus and
the modulus of rigidity for tin- same liody with sufficient accuracy to justify theoretical conclu-
sions. There seems to be a method of direct comparison which would test the question if the
experimental difficulties should not prove too great. If M is Young's modulus,

/= — F sin <p j M and 6 = — F cos $ / n,

If, then, a testing machine were so adapted as to produce a pressure at 45° to a stationary plane,
the deformation of a cube subjected to its action would give 6 ./and .1/ / n. If Poisson's hj pothesis
is verified, il//w = in I.

t Compare Thomson and Tait. Nat. Phil., section G83. For Poisson's solid 3 ft = 5m.

G2 G. F. BECKER FINITE STRAIN IN ROCKS.

Thus one may express e,/and g in terms of b —

e = c = - — • f= Ah

•10i/3' * ""IO1/3'

The line of unaltered direction is then given hy —

tan y. =«t-e = — -=- = ton 10° 4'.
6 2 ,/ 8

In the case of finite strain it has been shown that this angle preserves
its initial value unchanged : so that if b = -- 1, / — e = — 0.2887. Since
also e = — //4, the following is a consistent set of displacements for

f = 30° :

b = — 1 ; c = 0.0577 ; / = — 0.2308 ; # ■ = e.

Knowing the displacements, the corresponding values of v and a* may be
determined as has been shown in the earlier part of this paper. If these
angles only are required they may be found from the following formulas.
For any value of b when Poisson's ratio obtains —

tan u> =

l/(2— 3 ef + bl — y 25 e + 1/ .

2v/(l + e)2(l-4e)

^2y = -(i-4i)*-(it°«r-y

For the present displacements the formulas give —

m = 28° 43'; > = — 22° 37'.

For the spacing of the two possible sets of fissures, therefore—
w = I cos (w ± y) = (1 - 4 e) cos (« ± v),

which for this set of displacements gives 0.765 and 0.481.

Supposing that both systems of fissures form, the following diagram
(figure 10) shows their disposition at the moment of rupture*

* Example for <j> = 00°.— It may be of interest to some readers to give a second example of a similar
strain. In the diagram, figure 11, the force is supposed to art at t>0° to the plane of support. If.

also, 6 %, the following values result: e = 0.0866 ;/= — 0.3464 ; gr = e; xo = 36°35'; w=32°4';

v = — 16° 32'; ju. = — :J2° 34'; h = 0.9172; A = 1.230; 5 = 0.575; G = 1.087 ; D = orf = 0.869 : »
0.630 or 0.432. The range for one set of planes of maximum tangential strain is o° 21', and for the
other set 16° 26'.

EXAMPLES OF FISSURING.

03

It is apparent from the formulas that e and b fully determine w, v and
w. It is also true that if the two values of w and the angles between the

Figure 10. — Results of Rupture by Pressure at 30° to fixed Plane.

It is assumed that/= — 4e and that 6= — 1. Thus c = 0.0577 =g and/ = — 0.2309 ; to = 31° 20' ;
(o = 28° 42'; v = — 22° 37'; /«. = — 51° 19'; ft = 0.951; .4 = 1.562; £ = 0.521; C=1058: D — 0.92G;
w = 0 7U5 or 0.481. The range for one set of planes of maximum tangential strain is o° 41' and for
the other 28°.

cracks (or 2 w) were known by observation, the displacements and the
value of <p could be deduced. The two values of w would in such a case
enable one to find v and e, while when these quantities are ascertained,

Figure 11.— Results of Rupture by Pressure at 00° to fixed Plane.

the formula for tan 2 * will give b. Finally tan <p = 6/10 e. But to de-
termine the direction of the force in this manner it must be shown that

X— Buix. Geol. Soc. Am., Vol. 4, 1892.

64 G. P. BECKER — FINITE STRAIN IN ROCKS.

the masb Avas rigidly supported and that it was subject to no lateral con-
straint. Thus great caution must be exercised in applying this or any
similar method to geological occurrences.*

Distortion, on Planes of maximuip Strain. — It has already been pointed
out that the planes of maximum strain are not in general undistorted
planes. Consider one of the planes making an angles -j- v with the fixed
plane and inquire what ellipse on this plane would answer to a circle of
unit radius in the unstrained solid. Prior to strain this material plane
made an angle 03 with that radius of the sphere which ultimately forms
the minor axis of the ellipsoid. This radius also originally made an
angle — p- with o x. Hence it is easily seen that the original angle of the
plane to o x is 90° ■ — ■ (ro — (i).

If y is the original position of the extremity of the unit radius drawn
on the intersection of this plane with that of x y —

y = cos(m — //.).
If y' is the corresponding ordinate after strain —

y' = (1 +/) cos ( en— //.).
If the altered length of this radius is denoted by D, its value is given by —

n „// -; t _i_ ^ ( l+,f) cog (ro — ,a)

JJ = V Sill (OJ + v) == - — -. : r

J ' v J sin {cu + v)

It is easy to see that D is in general less than unity. Were the strain
plane and undilational, D would he unity, and this case is realized in
simple scission (or shearing motion), Avhieh may be tolerably frequent
among rocks. For a simple shear D would also he unity, but this is a
strain probably seldom realized. Whenever a compressive strain is
accompanied by two shears the radius in question undergoes contraction
and is less than unity.

On the other hand, the unit radius parallel to o z is elongated to
1 +p/ = l + e=Cby an inclined force.

Thus the ellipse on a plane making an angle o> -f- v with ox, whose
major axis is C'and whose minor axis is D, corresponds to a circle in the
original mass. The strain involves a compression in the direction of
M -f- v and an elongation in the direction o z.

* La'eral Constraint.— [fa mass were no! only supported on a rigid foundation but confined by rigid
walls perpendicular to th,e fixed foundation and parallel to the horizontal component of the force,
the strain is also easilj calculated on Poisson's hypothesis. Evidently g = 0, and it is easj w>see
that /= — 3e. Of course, 6 retains the same value as if there were no lateral constraint. 1 am no!
aware that any particularly interesting results arise in this case, which differs from plain undila-
tional strain only in the fact that there is cubical compression. It applies t" Mr Sharpe's theory of
slaty cleavage.

EFFECTS OF STRAIN DISCRIMINATED. 65

Various Results of Strain. — In the foregoing pages a theory of slow rup-
ture lias been presented, which will be supplemented a little later by
considering the possible effect of vibration in those cases in which the
rupture is sudden. Observation seems«to indicate that many rocks have
been strained to the breaking point so gradually that the theory developed
is applicable.*

In applying the results reached to the elucidation of geological phe-
nomena the physical character of the rock must be carefully considered.
Some rocks when strained with moderate rapidity approach in behavior
the ideal, elastic, brittle, non-viscous solid. h\ such cases an inclined
pressure will produce two systems of cracks sjich as those illustrated in
figures 10 and 11. If the mass is held in the strained state, so that the
fragments have no opportunity to recoil, the direction of the force may
then be inferred approximately by mere inspection. The plane in which
it lies will be perpendicular to th'o systems of fissures. Its direction will
intersect the obtuse angle made by the fissures, arid it will make a smaller
angle with the short side of the parallelogram of cracks bounding a
column of the rock than with the long side. The direction of the force
(•.■in be calculated exactly from the lengths of the sides of the parallelo-
gram and the angle between them, if Poisson's hypothesis is assumed.

If the rock is viscous but not plastic (or if it is strained under such
conditions as to bring the viscosity into play, but not to keep the rock
for a considerable time in a state of strain exceeding the elastic limit and
falling short of the ultimate strength), the effect of the viscosity on the
long sides of the parallelogram will be far greater than on the short sides,
because of the difference in range of the two planes of maximum tangen-
tial strain. He.nce fissures will form only in the directions of the short
sides of the parallelogram and the rock will be divided into sheets.

If the conditions are such as to develop both the viscosity and the
plasticity of the rock-mass, flow will tend to take place parallel to the
short side of the parallelogram because of the inferior viscous resistance.
If the plasticity is sufficiently great, the strain will not manifest itself as
rupture in this direction, but merely as plastic deformation. If the plas-
ticity is not sufficient to prevent all rupture, it will at Least diminish the
amount of rupture needful to relieve the strain, and there will be mingled
effects of deformation and rupture.

These mingled effects might consist either in a wider spacing of this
set of fissures or in the distribution of short cracks through the mass.
Of these the latter seems the more Drobable. The area corresponding to

♦ Striking instances of the rupture of casi iron blocks are depicted in the frontispiece of Tod-
hunter's History of Elasticity. In a general way they accord with the theory developed in the
text; but the blocks employed were too slender to give the full syst :m of fissures demanded by
the theory for slabs of moderate thickness and greai area.

GG G. F. BECKER — FINITE STRAIN IN ROCKS.

one parallelogram of the figures must receive a certain amount of relief,
and if this is not entirely accomplished by flow it must be completed by
rupture; but a rupture at each end of the parallelogram would relieve
the strain without the help of flow. Thus it appears most logical to
suppose that in such cases short " close joints " will be distributed through
the plastically deformed mass, excessively minute variations in the resist-
ance of the material determining their precise disposition.

The set of planes corresponding to the long side of the parallelogram
cannot behave in the same way as those already discussed. This set
sweeps through the mass so rapidly that there is no time for flow of con-
siderable amount to take place. Hence, if they receive expression at all,
it must be as sharply cut fissures or as u master joints."

Theory of Slaty Cleavage. — In considering what properties would he ex-
hibited by a plastic, viscous rock which had been rigidly supported and
subjected to a pressure inclined at a moderate angle to the plane of sup-
port, it is difficult to see how the mass would differ from true slate. The
relative tangential motion along the set of planes which eventually makes
an angle « d- ^ with the plane of support would inevitably manifest itself
as a cleavage, alternating in some cases with close jointing. In the direc-
tion of 02, or perpendicular to the plane of the figures 10 and 11, this
cleavage would be invariable. In the direction a> -\- v the cleavage would
be confined to a very small angle, less than one degree in the examples
given above. Thus the mass would cleave very sharply along lines
parallel to o z, less sharply along w 4- v- Expansion would take place
parallel to o z, while contraction would take place in the direction w -j- v.
This contraction might be accompanied by a puckering of the cleavage
surfaces, because the cleavage planes formed at the inception of strain
would be still further contracted as strain progressed. The amount of
relative distortion in the directions o z and <o + v would vary with the
direction of the force and the intensity of the strain. The only case in
which there would be no distortion on the cleavage plane occurs when
the force is parallel to the fixed support. All of these peculiarities of
this strain are characteristic of slate, and they seem to cover all of the
principal properties of that much-debated rock. I shall return to the
comparison of properties in a later portion of this paper.

Influence of Shock. — Although the preceding discussion shows how
sheets of rock may be produced by the action of orogenic forces, I am
not satisfied that all fractures are produced in this way. There seem, in
fact, to be instances in which the spacing of more or less nearly rectangu-
lar fissure systeaisis closer than can lie accounted for on the assumption
that the Assuring is of minimum amount.

THEORY OF SLATY CLEAVAGE. 67

If pressure is applied so rapidly that a considerable shock attends
nipt me a corresponding quantity of energy will remain in the fragmental
mass in t lie form of vibrations. These vibrations will take place along
the lines of unaltered direction, making an angle '■ with ox. In the ex-
treme ease of scission tins direction is also that of the lines of maximum
tangential strain. In every other case the vibrations will occur at an
acute angle to the planes of maximum strain, and in no instance will
they lie perpendicular to these planes.

At the instant when the rupture takes place the whole mass is strained,
in one or more directions, to the limit of endurance. Rupture and the
inception of waves of compression are simultaneous, and these waves are
propagated from the surfaces of primary rupture, but not perpendicularly
to them. The waves must interfere and. where they intensify one another,
there must he resultant shearing couples in the direction of the planes of
maximum tangential strain. These waves must be propagated at the
same rate that relief of pressure takes place, a rate dependent upon the
properties of the mass. If. then, the waves are of considerable ampli-
tude, it appears to me that on those surfaces at which they reinforce one
another, they must intensify the strain beyond the limit of endurance.

Thus there seem- sufficient reason to believe that a pressure very
rapidly applied, producing primary ruptures attended by shock, will be
immediately followed by secondary ruptures in the same direction as the
others at intervals dependent upon the wave length of the impulse. In
much the same way a high explosive shatters a rock far more than black
powder.

A phenomenon of which no explanation has been offered in this paper
is that of thick slates and of those flags which are to be considered as very
thick slates. These, though cleavable to a certain thinness, are not capa-
ble of further splitting. Such rocks indicate a flow which is not uniformly
distributed through the mass, hut, on the contrary, passes through maxima
at intervals corresponding to the thickness of a slate or flag. It is pos-
sible that at the inception of strain such masses were in a state of tremor
so intense that the interference of waves determined surfaces along which
flow began. These surfaces would be weakened by the flow, and further
strain would be distributed among them rather than over the intervening
solid sheets. Effects of a similar kind are produced on a pile of sheets
of paper, such as " library slips," resting on an inclined, cloth-covered
table which is jarred by rapid blows.

The question would seem to be one of the direction and intensity of
the vibrations rather than of their existence. The tendency of rectilinear
motion to pass over into molar vibrations of rapidly decreasing period is
so strong as to make it most improbable that such a distortion as is in-

68 G. F. BECK Kit — FINITE STRAIN IN ROCKS.

volved in the formation of slate should ever be unattended by vibrations
of sensible amplitude.*

Though this hypothesis of thick slates seems probable enough, I am
not able to offer a detailed explanation .of the process or to show under
what conditions thick slates would form rather than thin ones.

Secondary Action on ruptured Rock. — It often happens that the pressure
which causes such systems of fissures as have been treated above is not
fully relieved by these ruptures and the small relative movements in-
separable from rupture. If pressure continues on the divided mass the
results will vary with circumstances. When the pressure is oblique and
the mass is divided only into sheets, faults of considerable throw may
take place. I have previously discussed the distribution of motion in
such a system.t It appears from the present investigation that a simple
fault arises from pure scissive stress, while distributed faults are due to
pressure combined with scissive stress, or, in other words, to oblique
pressure. Thus a distributed fault is much the more general case and,
in my observation, much the more common. A solitary fault is an ex-
treme and very special case of a distributed fault.

At the instant of rupture there is very little normal pressure between
the sheets or blocks of rock, but as rotation progresses the pressure tends
to increase. Extensive movements are therefore accompanied by a forci-
ble grinding of the fragments against one another. At first the stresses
called into play are but little inclined to the surfaces, and the result is
often to produce slaty structure close to the surfaces of the fragments.
I have observed very many cases in which large blocks of granite showed
slaty cleavage close to the bounding surfaces which had evidently been
produced in this way. The cleavage was certainly in part due to close
jointing, but in mosl cases the cleavage faded out at some little distance
from the edge of the mass, and the inner portion of the slaty selvedge
must therefore have arisen from strain without rupture (Heim's Um-
formung ohne Bruch). Such slaty selvedges thus furnish important
evidence as to the manner in which slate is formed in nature, evidence
entirely accordant with that afforded by experiment.

When the secondary pressure becomes more nearly perpendicular to
the faces of the sheets of rock, these may themselves be divided into
secondary sheets, and a continuance of the process will reduce the rock
to a confused rubble.

Effect of tensile Stresses. — Jointing has been referred to tensile stresses
by several authors. It is therefore desirable to examine what effects
tensile si ress can have upon homogeneous substances. To give abstract

See Am. Journ. Sci., vol. xxxi, 1886, page 1 1 5.
f Geology of the < omstock Lode,U. - I. Surv., monograph iii, chapter 4.

SECONDARY RUPTURES. 69

t

ideas a concrete form, suppose that a hot cube of homogeneous matter
were to be cooled from one side only, and that the cooled surface under-
went contraction. This contraction would produce tension throughout
the cooling surface, excepting at the edges, so that the surface would
assume the form of a very shallow dish, as illustrated in the following
diagram :

^^~

— ^\

( ^

lJ

Figure 12. — Contraction of il/ass cooling from one Side.

Since the tension would be zero at the edge, it would clearly be greatest
at the center, and here rupture would take place in the surface film when
the tension reached the limiting value. The tension at the center might
he relieved by cracks of various characters. A single straight crack would
relieve it only in one direction, and would, in fact, tend to increase ten-
sion in the direction of the crack, because the crack must gape, and its
edges would therefore slightly exceed its median line in length. This
form of rupture is therefore impossible under symmetrical conditions.
The same objection applies to two cracks forming a letter T. Complete
relief at the center would be afforded either by an X_shaped crack or by
one in the form of a Y- Of these, the latter has the smaller total length
for a given intersected area. Now, the cracks will clearly form in such a
manner as to afford the greatest amount of relief per unit length of crack,
and hence the rupture will take the shape of the letter Y- This will
afford total relief at the center and partial relief at surrounding points.
This relief, under symmetrical conditions, must be equally distributed,
and therefore the three cracks must make with one another angles of
120°.

This simple inference is confirmed by observation. Thus, if one alb iws
a vessel containing melted wax to cool slowly, an excessively thin trans-
parent film forms on the surface. Then a minute opaque Y becomes
visible near the center. This is due to the cracking of the film and the
great acceleration of the process of solidification on the sharp exposed
edges. So, too, a slight blow on glass often produces cracks in the same
shape. Cracks in asphalt pavements frequently show a tendency to the
same form; so do those in drying mud, and many of the divisional sur-
faces in columnar lava meet one another at angles approaching 120°.

As the coaling progresses the cracks must extend from the center; but
the longer they are the less is the relief which they afford in the circle
circumscribing their extremities and, unless the cooling area is small,

70

G. F. BECKER FINITE STRAIN IN ROCKS.

other cracks must form. Either, then, rupture will take place at new
centers or the original cracks will branch at their ends. A greater
amount of relief for a given length of crack will be afforded by the latter
method. The branches will be thrown off at angles of 120° for the same
reason that the first cracks formed this angle. As the process continues
the branching will be repeated, and it is evident that the surface will be
divided into regular hexagons. The more slowly the cooling progresses
the smaller will be the tension in the exposed surface and the larger will
the hexagons be.

FiciuiiK 1?,. —Primary tension Cracks.

In some cases tension may accumulate in one of the hexagons after
division to such an extent that a secondary rupturing takes place. This
too will begin by three radiating cracks at the center, and these must be
perpendicular to the greatest tensions or to the lines joining opposite
angles of the hexagon. They will thus divide the hexagon into inequi-
lateral pentagons, and the secondary fissures will be at right angles to
the sides of the hexagon.

Figube 14.— Secondary tension Cracks.

The tensions are due to stresses acting at the isothermal surfaces and
tangential to them. Hence, if the mass cools faster at one side than at
the other, the resulting columns will be curved and will everywhere be

COLUMNAR STRUCTURE. 71

perpendicular to the isotherms for which the tensions reach the limit of
cohesion.

Each of the columns cools as a separate body, and if the following
figure represents a vertical section of one of them, the dotted lines approxi-
mately represent the position of the isotherms. In the separate column
the tension will be greatest at the edges, because these, exposing a great
surface per unit volume, will chill most rapidly. When the column lias
reached a sufficient independent length, the tension on the edges will be
so great that they will rupture perpendicularly to the isotherms. These
ruptures will cut inward from the sharp edges and divide the columns
laterally by cup-shaped surfaces. The interval between these vertical
subdivisions of the column depends on the amount of tension which the
mass can stand without rupture, and will evidently be of the same order
as the diameters of the columns themselves.

Figure 15.— Cooling of Columns.

The foregoing deductions all correspond very closely to the phenomena
of columnar structure in massive rocks. Basalts, diabases, and the like,
however, are far from being homogeneous, and it is surprising that the
surfaces of the columns should be so smooth. If one were to cut a
suitable bar of diabase and" break it by tension in a testing machine the
fracture would certainly lie much rougher than the side of a diabase
column. This seems to be accounted for, at least in part, by the fact that
rupture probably takes place immediately after solidification of the
groundmass and before any difference in rate of cooling between the
embedded crystals and the groundmass has locally weakened the cohe-
sion of the latter. When masses of mud in drying out split into columnar
fragments, the torn surfaces are less smooth and the divisions less regular*

Review of Theories of slaty Cleavage.

}\liy Needful. — So little attention lias been paid by geologists to systems
of faulted fissures that the field may be said to be a new one. I know

♦ There is an intimate connection between the problem of columnar structure and that of the
division of space with minimum partitiona) area. See an investigation of tic latter subjeel by Sir
William Thomson (Lord Kelvin), Mittag-Lefflers Acta Math . vol. 11, 1887-88, p. 121, and Plateau,
Statique des Liquids, vol. 1.

XI— Bull. Gkoi,. Soc. Am., Vol. 4, 1892.

72 G. F. BECKER FINITE STRAIN IN ROCKS.

of no serious attempt to deal with the mechanics of the subject prior to
a paper already cited, in which I discussed those cases of rupture in
which the deformation could properly be regarded as infinitesimal. The
results there reached have been born out by further observation. In
this paper the investigation has been extended to cases of faulted fissures
in which deformation of the rock is finite, and the conclusions certainly
accord with very numerous observations which I have made in the Sierra
Nevada of California and elsewhere, nor are any facts known to me which
seem in conflict with the theory presented.

On the other hand, jointing and slaty cleavage have been much dis-
cussed. Some authorities regard them as closely allied, while others
refer them to radically different causes. Many experiments have been
made on slaty cleavage and various theories have been propounded to
account for it. The theory here advanced is new, and I may say that it
is a surprise to myself. I have long felt that the theory which refers
slaty structure to a pressure perpendicular to a fixed plane of resistance
and parallel to two lateral constraining planes was unsatisfactory. The
combination seems too artificial. The chances against its occurrence
seem too large when the frequency of slaty structure is considered. I
did not anticipate, however, that analysis would show so large a range
of conditions under which slaty structure might result, and I entertained
the idea that if a slanting force produced slaty cleavage the force would
slant in the direction of the grain of the slate. I have been led by purely
algebraical reasoning to believe that the force may be inclined to the
fixed plane within very wide limits, covering at least 60°, and that in
all cases the plane of the force is at right angles to the grain of the
slate.

Under these circumstances it is absolutely necessary to pass in review
the principal theories hitherto advanced and to compare the new theory
with the results of experiment and observation.

Origin of Jointing. — Joints are commonly nearly plane surfaces dividing-
rock masses and arranged in groups, the members of which are parallel
to one another. Fault fissures are also frequently arranged in similar
groups, and show similarly flat surfaces, the term joint being employed
when the amount of relative motion on the divisional surfaces is imper-
ceptible or is regarded as negligible. Jointing has been referred to ten-
sile stresses by distinguished authorities, including W. Hopkins, but the
correctness of this reference lias been questioned. Thus, Professor W.
King* after special investigation, stated his opinion that, in their original
condition, the walls of joints were in close contact, and protested against
the classification of columnar structure with jointing. Mr G. K. Gil-

*Trans. K. Irish Acad., vol. 25, 1875, p. 605.

JOINTING. 73

bert* also draws a contrast between the divisions of a mass due to
shrinkage cracks and those known as jointing.

There can be no question that jointing is due to mechanical causes ;
for joint planes cut through conglomerates with almost the same regu-
larity that they divide the most homogeneous rocks. They must, there-
fore, be due either to tensile stresses or to compressive stresses. In the
former case the joints must gape when first formed. I am fully satisfied
that Professor King was correct in asserting that the surfaces are usually
in close contact immediately after rupture. In very many cases disloca-
tion has taken place on jointed surfaces and, where this has occurred,
any irregularity in the surface will force the walls asunder.

It has been shown in the preceding pages that the columnar structure
of lava is easily accounted for, but I know of no way in which such a
S}rstem of divisions as occurs in jointing can be accounted for by ten-
sion, f

On the other hand, it is not difficult to show that most of the phe-
nomena of joints are fully accounted for by pressure, direct or inclined ;
but to this statement there is one exception. If joints are produced by
pressure, they are due to a tendency of the rock to move in opposite
directions along the joint plane; or, in other words, to a tendency to
faulting. Hence, if pressure is the cause, there is no distinction, except-
ing one of degree, between joints and faults.

There is no doubt whatever that faults are often met Avith on joint
planes, yet this association is no proof that the two phenomena are not,
as they have often been assumed to be, independent of one another.
But the study of many thousand divisional planes which would cer-
tainly be regarded as joints by almost every geologist has led me to the
conclusion that the jointing and the faulting are concomitant. The
faults are often extremely small, but it is very rarely that in a system
of joint planes throws of an eighth of an inch or less cannot be detected ;
and where the rock is hard, slickensided surfaces will lie found even
when the relative movement is much less than an eighth of an inch.
Few geologists have been in the habit of looking for faults of such tiny
dimensions, and I believe that the distinction between faults and joints
has arisen from this omission. Partings due to tension would be free
from slickensides.

It might be thought that a refutation of this conclusion is to be found

'6

* Am. Jour. Sci., vol. 24, 1882, p. 50.

t Divisional surfaces produced by pressure differ from those produced by tension in a manner
which is distinguished even in ordinary parlance. Rupture under tension is only another name
for tearing, while division under pressure always involves as an essential feature that sort of cutting
which is performed with scissors or shears. Thus the very similes employed in describing rock

fractures often indicate an instinctive perception of the mechanical pr sses involved, even when

an attempt is made to reconcile phenomena with a less natural theory.

74

G. F. BECKER FINITE STRAIN IN ROCKS.

in the fact that joints frequently die out; but faulted fissures, even those
carrying important ore deposits or considerable dikes, also die out.
Nevertheless, the dying out of joints shows that the movements involved
must at some points be microscopic, and indeed submicroscopic.

M Daubree has succeeded in reproducing jointed structure in the
most striking manner by pressure on mixtures of beeswax and resin.
The following cut is copied from his experimental geology and explains
itself:

Figure 10. — DaUbr&e's Experiment on Crushing.

Here, as in nature, there are joints which die out, but they are associ-
ated with faults of measurable throw. The system of divisions is pre-
cisely that deduced for a direct pressure in the earlier portions of this
paper from the theory of strain.

Still another lesson can be learned from this experiment. The sides
of the crushed column bulge in such a manner as to show that plastic
deformation has taken place as well as rupture. Now since these rup-
tures can be conceived only as relative tangential movements pushed to
the limit of cohesion, it seems to me clear that the plastic deformation
also must consist in relative tangential movement, and. indeed, in the
same directions as the joints, but not reaching the limit of cohesion. If
one inquires what is the effect of this plastic movement on the structure
of the mass, one can only reply that it must be something very analo-
gous to schistosity.

EXPERIMENT BY DAUBREE. 75

Others have made experiments with similar results. It is well known
that east iron, building stone and similar substances, crushed in testing
machines, do not yield on planes parallel to the support, but at angles
approximating to 45°, when the slabs are broader than they are thick.
Not all of the cracks pass through the masses experimented upon. The
slabs are somewhat deformed, and, in short, the phenomena are strictly
comparable with those of M Daubree's experiment, though less bril-
liantly illustrated.

Jointing and Cleavage. — -Many geologists have been struck by the inti-
mate manner in which jointing and cleavage (whether schistose or slaty)
are associated, and there seems to have been a growing tendency to assert
or imply a relationship between them, even in spite of an assumed theo-
retical difference in origin. Professor William King advanced the
hypothesis in 1857 that slaty cleavage was derived from jointing, the
jointed surfaces having been welded under pressure. This conclusion,
indeed, has not, to my knowledge, been adopted by any other observer;
but rejection of the conclusion does not imply rejection of the facts upon
which it was based — viz., that dislocated jointing occurs " developed to a
degree of fineness bordering on that of mineral cleavage," as at Carragrian,
near Galway, and the occasional alternation of joints with parallel slaty
cleavage* Professor A. Heim distinguishes cleavage due to microscopic
dislocated joints from cleavages unattended by joints, or true slaty cleav-
ages. Of these he makes two classes : " micro-cleavage," consisting in a
flattening of the component grains of the rock, and cleavage due to the
re-arrangement by pressure of previously existing scales in positions more
and more nearly perpendicular to the line of pressure. All three varie-
ties are associated so intimately, according to Heim, as to be found in
one and the same thin section. Even in cases of pure micro-cleavage
relative movement without fracture in adjoining cleavage planes may be
detected.f M Daubree speaks of " the surfaces of slipping which pro-
duce schistosity ; "J Dr H. C. Sorby has described cases of discontinuity
on a microscopic scale which lead to cleavage; Messrs (leikie, Peach and
Home describe fluxion structure and shearing as productive of schistosity
and highly cleaved rocks, the planes of cleavage being parallel to the
thrust plane, ^ and other similar observations could be cited to show that
relative tangential motion and slaty cleavage are at least most intimately
associated in nature.

Phenomena of slaty Cleavage. — Workers in slate distinguish not only the
cleavage laces, but also " side " and " end." Most slates can be split only

* Trans. R. Irish Acad., vol. 25, 1875, p. 612, et passim.
fMech. der Gebirgsbildung, vol. 2, 1.S7S, pp. 54-56.

X Etudes SynthiHiqiii's, 1879, p. 321.
I Nature, vol. 31, 1S84, pp. 29-35.

76 G. F. BECKER — FINITE STRAIN IN ROCKS.

in one direction, which appears to be usually that of the dip of the slate
in its original position. A block of slate thus bears some analogy to a
block of wood, so far as its fissility is concerned. In some cases, how-
ever, slates are said to split equally well from any edge of a block.
Fossils occurring in slate are usually distorted, and numerous measure-
ments of these fossils have been made for the purpose of ascertaining in
which direction the greatest elongation and contraction have taken place.
As might be expected, these measurements do not accord very closely,
for it is difficult to expose a fossil in such a manner that all its dimen-
sions are accessible without obscuring the relations of these dimensions
to the dip and strike of the slate. Sometimes there seems to be no rela-
tive distortion in the plane of the cleavage. In other cases the fossils
are greatly distorted in the cleavage plane, the longer axis coinciding
with the dip.

Figure 17. — Steps in Slate.

It is frequently asserted that the greatest elongation of the fossils is
always in the direction of the grain of the slate, and the greatest con-
traction perpendicular to this direction. This implies that there has
been no tangential movement among the laminae, or that there is no
fluxion structure and no close jointing or "Ausweichungsclivage " in the
rock; for in any such case tlie axes of the strain ellipsoid must fail to
coincide with the dip, the strike, and the perpendicular to the cleavage.
Now these structures are known to be frequent in slaty rocks and dis-
tinguisbable from true, slaty cleavage only under the microscope. The
deductions from the measurements of the fossils can therefore be only
approximately true. I have myself seen fossils in slate in which fluxion
structure was plainly manifested, in my opinion, and in tbat of an emi-
nent paleontologist whom I consulted. Slaty developments of crystal-
line rocks are by no means unknown, and these are closely allied to

CHARACTERISTICS OF SLATE. 77

schistose rocks, in which crystals have certainly undergone distortions
involving fluxion phenomena.

In slate quarries there are usually " steps " produced by the presence
in the slate of strata differing in lithological character from the hulk of
the rock. The cleavage is deflected by these strata, and when they are
sharply defined the deflection is also sharp. When the cleavage is at
right angles to the stratification the deflection is nearly or quite imper-
ceptible, and it seems to be maximum when the angle approaches 45°.
The illustration on the opposite page is taken from Mr Alfred Barker's
admirable memoir on slaty cleavage*

All of the above phenomena must of course be accounted for in any
satisfactory theory of slaty cleavage.

Theories of slaty Cleavage. — The earlier geologists naturally associated
slaty cleavage and mineral cleavage, and ascribed both to the same or
similar causes. Professor John Phillips was the first to offer a mechani-
cal explanation.f In doing so he was prudently indefinite. He de-
scribed the distortion as a " creeping movement among the particles of
the rock, the effect of which was to roll them forward in a direction
always uniform over the same tract of country." This language has been
interpreted as equivalent to the hypothesis of a simple " shearing motion,"
but it will by no means bear this limited construction. Phillips had in
mind a rotational strain and a fluxional structure, but his paper contains
nothing to indicate the absence of forces acting perpendicularly to the
cleavage planes. He neither denies nor asserts the cooperation of such
forces. He also says nothing to indicate that his theory was applicable
only to heterogeneous matter, and it is fair to conclude that he supposed
that slate might be produced from homogeneous substances.

Mr D. Sharpe explained the structure as due to the contraction of rock
in the line of pressure and a partially compensating elongation at right
angles to it. This strain is one of two dimensions, and consists of a
simple shear (not a shearing motion) with a cubical compression. The
fissility produced he referred to the fact that a fracture perpendicular to
the direction of pressure would run along the flattest faces of the compo-
nent grains and meet the smallest number of them. This explanation
implies that the mass is heterogeneous, and that the adhesion between
the component particles is smaller than the cohesion within the particles.];

Dr H. C. Sorby, to whom geology owes so great a debt for the introduc-
tion of the microscope as an instrument of lithological research, natur-

* Brit. Assoc. Ad. Sci., 1885, p. 813. Mr Harker's paper contains very full citations of the literature
of slate, and the reader who cares to pursue the subject is advised to consult it. No attempt is
made in the present paper to give a full bibliography.

f Brit. Assoc. Rep., 1843, p. 61.

JQ. Jour Geol. Soc, vol. 5, 1849, p. 128.

78 G. F. BECKER — FINITE STRAIN IN ROCKS.

ally attacked the question from a microscopical standpoint. He found
that the mica of the slates was largely concordant with the cleavage and
referred the fissility to the effect of direct pressure in deflecting mica
scales toward a direction at right angles to the line of pressure*

This theory is supplementary to that of Mr Sharpe, and it is to the
united effect of the flattening and deflection that slaty cleavage is now
usually ascribed.

Mr A. Laugel assumed on the authority of Sharpe that the strain con-
sists of a simple shear. He pointed out the fact that in a simple shear
in a homogeneous mass the planes of least resistance (or, as I have called
them, of maximum tangential strain) stand at an angle with the axes
of the shear dependent upon the deformation. In the notation of this
paper f he reached the result tan2 w == BjA. He gave no proof of this,
however, and did not explain how the double cleavage implied in this
equation of the second degree could I >e reduced to the simple cleavage
of slate. X In my opinion he was on the right path to a sufficient expla-
nation, but he certainty did not achieve it.

Professor John Tyndall's famous experiments on slaty cleavage in
wax in a direction perpendicular to the pressure were published in 1856.§
He dissented from Sorby's theoiy, regarding his wax as homogeneous,
and finding that the intermixture of scales rather interfered with than
promoted cleavage. Dr Sorby replied to Tyndall, citing experiments of
his own on clay mixed with mica scales and pointing out that wax con-
tains prismatic crystals ; so that, in his opinion, the wax must be consid-
ered as composed of elongated elements capable of re-arrangement by
pressure, according to his theory. ||

Mr Daubree found that clay without mica scales when extruded
through a small opening assumes a schistose structure, the lamination
being close in proportion as the material is more finely divided.^] He
also obtained evidence of schistose structure in flint glass, softened by
heat and forced through an opening. In this case at least there could
be no question that the resultant structure was independent of hetero-
geneous particles.

Dr Sorby made an addition to his theory of slaty cleavage in 1880.
In his original theory it was assumed that the mica before compression
was distributed through the mass without any order. As a matter of fact,
the mica scales in shale are, for the most part, parallel to the bedding.

*Ed. New Phil. Mas;., vol. 55, 185:;, p. 1::;.

fSee formula (9), p. 33.

tComptes Rendus, vol. 40, 1855, p. 978.

gPhil. Mag., vol. 12, 1856, p. 37.

|| Phil. Mag., vol. 12, 185G, p. 127.

|G6ol. Exp., 1879, p. 413.

THEORIES OF SLATE. 79

In certain cases, however, he observed that the bedding was almost
obliterated by the disturbances due to the pressure. The supplementary
hypothesis is that the preliminary effect of pressure is to give the mica
an irregular distribution, the final effect being to rearrange the mica
scales in the planes of cleavage.*

Objections to the Hypothesis of Heterogeneity — In my opinion, there are
the gravest objections to the hypothesis that slaty cleavage is due to the
lack of homogeneity of a rock mass which has been subjected to the
action of force. Neither Tyndall nor Daubree found that the presence
of scales promoted schistosity, but just the reverse. The wax employed
by Tyndall may have consisted largely of prismatic bodies ; but before
pressing his wax he softened it, making these bodies, as well as their
groundmass, very plastic. He also kneaded the mass, so that the com-
ponent particles must have welded. Even if every one of the prisms had
assumed a horizontal position, there is no reason to suppose that the
cohesion between them and the groundmass of the wax was feebler than
that between the different portions of any one prism, or that any schis-
tosity, at all approaching slaty cleavage, would have resulted. Similar
remarks apply to Daubree's experiments on clay.

Dr Sorby's supplementary hypothesis is suggestive in the same con-
nection. All geologists will grant that disturbances are sometimes such
as nearly or quite to obliterate the bedding of shales, but none will assert
that this is a condition of slaty cleavage. We all know that the bedding
is often most distinctly preserved in masses of roofing slate, and that the
lamination is not infrequently fairly regular. In such cases it seems to
me impossible to contend that the mica scales originally concordant with
the bedding have been stirred up in such a manner as to be distributed
at all angles through the mass. Again, there are many somewhat indu-
rated shales not affected by slaty cleavage in which there are countless
mica scales, nearly all of them concordant with the bedding. If the dis-
tribution of mica scales constituted the fissility called slaty cleavage,
such beds should split like slate in the planes of bedding. Such beds
are sometimes fissile to a certain extent, but cases in which this fissility
could be mistaken for slaty cleavage are very rare, if, indeed, any are
known. When rocks split along their lamination at all like slate, geolo-
gists expect to find, and usually do find, that the rock possesses true slaty
cleavage coinciding locally in direction with the planes of bedding, but
superinduced upon and independent of bedding;

Similar objections apply to Mr Sharpe's theory of the flattening of the
rock components. It affords no explanation of Professor Tyndall's ex-
periments, and were it correct some tine-grained sandstones, at any rate,

*Q. Joui-. Gcol. Soc, vol. xxxvi, 1880, p. 7;i.
XII— Bull. Geol. Soc. Am., Vol. 4, 1892.

80 G. F. BECKEB — FINITE STRAIN IN HOCKS.

would cleave along the bedding exactly like slate which docs not accord
with observation*

It appears to me, therefore, that no theory of slaty cleavage will be
satisfactory which does not apply to the case of homogeneous matter.

Analysis of Experiments. — Slaty cleavage has been produced artificially
in several different ways. Plastic substances compressed between rigid
masses exhibit such cleavage; so too do plastic masses extruded through
small openings ; poor qualities of iron or brass when drawn to wire often
show thin splinters, indicating the presence of cleavage; metals, pastry
and clay rolled out into sheets show similar fissility, and. as Professor E.
Reyer has pointed out, the bruise produced on soft rocks by a slanting
blow with a pick exhibits a like structure. r

These cases seem very different, but they must have common features,
unless, indeed, slaty cleavage is due to essentially diverse causes. Most
of the mechanical operations indicated are very complicated, hut their
common features may be reduced to simple terms by considering a very
small cubical portion of the mass before distortion and inquiring how it
is affected by strain.

Figure 18. — Origin of Cleavage in Wire.

If one end of a wire is filed to a flat surface perpendicular to its axis.
and the wire is then drawn through two or three successive holes of a
draw-plate so that the flat end is the last to come through, it will he
found that this end has become concave. If one considers a small cube
in the undistorted wire, not on the axis, it is clear that this cube will be
converted into an oblique parallelopiped, as is illustrated in the foregoing
diagram, showing the wire in section.

The concentric layers of the wire move upon one another much like
the joints of a telescope. The little cube is elongated in the direction of
the axis, its height is diminished, and its right angles in the plane of the
axis are converted into acute or obtuse ones. It is clear that the sphere
which might he inscribed in the small cube has been distorted to an
ellipsoid, the major axis of winch becomes more and more nearly hori-
zontal as the strain increases. The strain is thus a rotational one. and.
according to the theory of strain set forth in this paper, a cleavage should
be developed nearly in the direction of the axis.

*See p. 74.

f Theoretische Geologie, 1888, p. ."iTT.

ARTIFICIAL SLATY CLEAVAGE.

81

If a bar were substituted for a wire, and slots for the circular openings
of the draw-plate, the strain would be exactly equivalent to that pro-
duced by an inclined pressure acting on a rigidly supported cube. It
cannot be doubted that in such a case the end of the bar would also
become concave, and that evidences of schistosity would appear.

When a plastic mass is extruded through a small opening, whether
circular or rectangular, the action is very similar to that involved in
drawing wire, excepting that the external force is a pressure instead of a
tension. The friction on the moulding surface delays the motion of the
external layers relatively to the internal layers, and so-called "fluxion
structure results. In the following diagram it is plain that a cube of the
plastic mass at a would become an oblique parallelopipedon at 6*

Fiouke 10. — Development of Cleavage by Extrusion.

When an oblique blow is struck with a pick the bruise will manifestly
show a distortion of a very small cube similar to those already considered.

The case of a direct pressure, such as was employed by Professor Tyn-
dall, seems at first sight very different from the foregoing. To convince
myself as to the mechanics of the matter I repeated his experiments,
with the following results : f A cake of wax can be compressed to less
than half its thickness between glass plates well greased with a heavy
oil without bulging of the edges, as shown in figure 20, a, b. If such
cakes are cooled to — 15° C. they show no slaty cleavage, but exhibit a
tendency to split at an angle of some 60°, more or less, to the line of
pressure. If the plates are not greased, hut only wet with water, as in
Tyndall's experiments, there is ;i strong tendency to bulge along the

*M Daubr6e, in his Geologie Experimentale, r. mm. ids striking experiments on this mode of de-
formation.

f White wax is I irtter than yellow for the purpose of this experiment. To get comparable masses

least cylindrical cakes at as low a temperature as practicable. These wen led off and then

kept iu water at about 40° C. for an hour or more. I', -low this temperature the wax is boo hrittle to
mould with ease or rapidity. The compressed cakes were cooled in ice and salt. Cakes chilled
without preliminary distortion show no cl savag • under the hammer or chisel, and Crack \ ery like
fine-grained basalt.

82

G. F. BECKER FINITE STRAIN IN ROCKS.

edges, so that the cake assumes the form of an ordinary American cheese.
Cakes compressed to one-quarter of their thickness were very greatly
distorted in this sense, as shown in figure 20, c. When cooled and struck
sharply on the edge with a hammer, they showed slaty cleavage. The
character of the distortion of a small included cube follows from the dis-
tortion of the mass, and, as appears from the following diagram, it is a
distortion similar to that which takes place when a cube is subjected to
inclined pressure, as illustrated in figure 6, B, page 5V).

The reason for the bulging edges is at once seen to be the frictional
resistance between the glass plates and the escaping wax. This resist-
ance, combined with the vertical pressure, gives resultant forces, marked
r r in the figure, which are not vertical but lie on conical surfaces about
the central vertical axis. When this friction is obviated by the use of a
lubricant, so that a nearly uniform distribution of pressure is obtained,
there is no tendency to relative horizontal motion among the layers, and
in a dozen or more trials with lubricators I failed to find any trace of
horizontal cleavage. A tendency to cleave is sensible in these cases, but
it coincides with the planes of maximum tangential strain as nearly as
the imperfection of the surfaces enabled me to judge.

Figure 20. — Developmt ni of Cleavage by direct Pressure.

Thus it appears to me that Professor Tyndall's brilliant experiment
has been misinterpreted. He produced slaty cleavage not by a pressure
uniformly distributed and vertical to the cleavage planes, hut by a sys-
tem of forces inclined to the cleavage planes.

The effect of rolling metal, clay, or pastry is similar to that of direct
pressure combined with lateral friction. A cake of plastic material is
reduced to a sheet with bulging edges like figure 20, c, and an infinitesi-
mal cubical portion of the mass is distorted as in the other cases.

I am aware of no other ways in which slaty cleavage has been pro-
duced artificially. In all of those discussed the distortion attending
development of the cleavage is substantially the same. The elementary
cube is deformed as it would be by a force inclined to one face of the
cube when the opposite face rests upon an inflexible support. In some
cases there is lateral constraint ; in others there is none. The splinters
on rolled metal and pastry seem to show that the cleavage developed is
not quite parallel to the surface of the mass.

tyndall's experiment. S3

It might seem as if the varying directions of pressure detected in Tyn-
dall's experiment were geologically unimportant. Granting that the
vertical, uniform pressure at first applied to the wax is conically resolved,
does it not follow that in orogenic movements also a similar resolution
occurs ; so that, after all, slaty cleavage is due to a pressure originally
uniformly distributed and perpendicular to the cleavage? This query
must receive a negative reply.

The reason why the pressure in the experiment is resolved into a
conical system of forces is that the hodies between which the wax is
squeezed do not themselves yield sensibly. Thus horizontal relative
motion attended by friction is brought about. Were these bodies as
soft as the wax, they too would extend, laterally and the pressure
would remain uniformly distributed. It would also produce no slaty
cleavage.

In orogenic movements there is seldom any diversity between the
resistance of adjoining rock masses approaching the difference between
plates of glass and warm wax. Among rocks, therefore, a direct pressure
will, as a rule, be distributed with an approach to uniformity, and there
will be little or no relative motion between adjoining rock masses in
directions perpendicular to the pressure. Hence, also, important masses
of slate will not be produced in this way.

Perhaps no combination is entirely wanting in mechanical geology.
In artificial cuttings, clay beds underlying harder materials have been
known to be squeezed out laterally, and these masses must have been
affected like the wax in Tyndall's experiment ; but this case scarcely
forms an important exception.

In most cases of the geological occurrence of slate there is little direct
evidence of the mode of formation, and it is for this reason that the ex-
periments are of so much value. Sometimes, however, the method of
formation of natural slate is clear. I refer especially to the slaty selvedges
which are not infrequently seen bounding small faults in granite and
which have been mentioned under the head of secondary action on
ruptured rock. No geologist can doubt that these selvedges are produced
by the inclined pressure attending faulting, and it is manifest that the
distortion of an elementary cube would be exactly that which so con-
stantly accompanies the artificial production of slaty cleavage. Thus, in
some cases at least, natural slate is produced by the same means which
are employed in producing artificial slate.

Behavior of included Grit Beds and Fossils. — The theory that slate is
produced by a uniformly distributed pressure perpendicular to the planes
of cleavage, such as it has been usual to suppose existed in Tyndall's
experiment, implies that the strain ellipsoid is an oblate figure of revolu-

84 G. F. BECKER — FINITE STRAIN IN ROCKS.

tion. In such a slate a fossil which lay in the cleavage plane would

simply be flattened. From the observed fact that fossils are frequently,
though not always, relatively elongated to a sensible degree in one direc-
tion in the cleavage plane, Mr Sharpe inferred lateral confinement as well
as vertical pressure.

On the theory of inclined pressure, a fossil would always be elongated
in the direction of the grain of the slate and contracted across the grain
in the cleavage plane, excepting when the pressure made no angle with
the fixed plane. A still greater elongation, however, would take place
in the direction of the major ellipsoid axis, called A in this paper, which
is at right angles to the grain and makes a large angle with the cleavage
plane. That such distortions do exist I have convinced myself by the
examination of specimens, but I have not had an opportunity of examin-
ing any large collection of fossils from slates with reference to this point.

The relations of beds of hard grit occurring in slate bear a close rela-
tion to those of fossils. If such a bed were bounded by surfaces parallel
to the plane x y (or A B), the bed would behave either to a vertical or to
an inclined pressure as an independent mass. On the currently accepted
theory it would develop a horizontal cleavage. On the theory of inclined
pressure it would develop a cleavage in a direction between that of the
pressure and that of the fixed plane; and this would nearly coincide
with the cleavage of the surrounding softer mass, because the direction
of cleavage lies near that of constant direction and changes but little
during strain. The smaller the angle which the force makes with the
fixed support, the smaller would the divergence in the two cleavages be.

" Steps " are produced when a grit bed cuts the cleavage across the
grain, the plane of the cleavage in the slate and the surface of the grit
bed making an acute angle. The grit is a harder material than the slate,
and the cleavage developed in the grit makes a larger angle with the
bedding than it does in the slate.

To account for steps according to the theory of inclined pressure one
may consider the elementary stresses separately. It has been shown
that the shear in the plane B C does not tend to produce relative motion
on the cleavages. One may therefore suppose the stress, minus this shear,
to be applied to the rock first, and this shear to come into action later.
Figure 22, a represents a cube in the y z plane, with a layer of harder
material passing diagonally through it. If a shear and a shearing motion
or scission in the x y plane are impressed upon this mass, both portions
must yield simultaneously, because if the force were insufficient to strain
the harder layer, this would protect the surrounding mass from the action
of the force. Hence these strains would produce in both masses a cleav-
age, the traces of which on the y z plane would be parallel to o z, and

STEPS IN SLATE. 85

the appearance of the mass would be that shown in figure 22, b, where
the fine horizontal lines represent mere cleavage, not partings. Now let
the final shear at right angles to the x y plane be applied. It will elon-
gate the mass in the direction o z and contract it in the direction o y. But
since the more rigid layer yields to this stress less freely than that in
which it is imbedded, the grit bed will rotate more nearly as if it were a-
rigid mass, and will assume such a position as is shown in figure 22, c
In short, the hard layer will be deflected in just the same way that an
imbedded scale of mica parallel to it would be deflected. Thus the
cleavage in the hard layer will not be parallel to that in the adjoining
mass and will form a larger angle to the bed planes.

It thus seems sufficient to suppose the grit bed to have a greater coef-
ficient of rigidity to account for the phenomena of steps.*

*Dr Sorby's theory of this phenomenon, as stated by Mr Harker, is as follows: "Since the grit
yields less than the slate to the compressive force, the total voluminal compression is greater for
the slate than for the grit. Hut near the junction of the two rocks the change of dimensions in the
direction parallel to the bedding must be the same for both. Consequently, in the direction per-
pendicular to the bedding, the slate undergoes a less expansion (or greater compression) than the
grit; and the cleavage planes, which are in each rock perpendicular to the direction of greatest
compression, will therefore be less inclined to the bedding in the slate than they are in the grit.'-

This is a very ingenious explanation, but I have not been able to convince myself that it is sound.
It depends primarily upon the hypothesis that a large cubical condensation is involved in the
production of slate. This certainly docs not seem to be the case when slaty cleavage is produced
in moist clay or wax, for such substances are probably compressible only to a very minute extent.
It also implies that there is a very great difference between the cubical compressibility of the grit
and the shale. I know of no good reason to suppose that such a difference exists. The difference
in hardness does not imply such a relation, for cast iron, though so much harder than gold, is
nearly three times as compressible ; but even if it be granted that the relations of compressibility
are those demanded, it is not clear that any means is provided of changing the direction of the force
in the manner required by Sorby's theory of cleavage.

One may suppose a cubical portion of a rock mass to undergo the pressure needful to develop
slaty cleavage without change of volume, and that cubical contraction takes place subsequently. If
the mass contains a stratum of smaller compressibility than the remainder, the cleavage on the
theory now under consideration would be perpendicular to the direction of the force throughout
the mass before cubical contraction occurred. In this stage the mass would have the appearance
of figure 22, b. The effect of the shrinkage would then be to deflect the slaty laminae close to the
contact in curves with points of inflection at the contact, but to leave the direction of the cleavage
at a little distance from the contact unchanged. The appearance after cubical contraction would
would then resemble that illustrated in the following diagram :

Figure 21. — Effects of Compressibility.

But this does not represent the phenomenon to be accounted for; so thai although the hypothesis
of varying cubical compression would explain a change of direction in the surfaces of cleavage al
the contact with a gritty bed, it does not, so far as I can see, account for steps.

86

G. F. BECKER — FINITE STRAIN IN ROCKS.

Conclusion as to Sidle. — The fact that slaty structure occurs not only in
argillaceous rocks hut, though less frequently, in limestone, grit beds,
granite and basic eruptives, while it has been artificially produced in
wax, clay, metals, dough and glass, throws much doubt on the hypothesis
that slaty cleavage is due to re-arrangement under pressure of embedded
flakes and grains of matter. This doubt seems confirmed by the fact
that although the component grains of many undisturbed shales and
sandstones are so arranged that their largest sections lie parallel to the
planes of bedding, such rocks do not show any cleavage closely resem-
bling that of slate. Hence a satisfactory explanation must apply to
homogeneous matter.

Examination of the experimental methods of producing slaty structure
shows that in all cases the distortion of a small portion of the mass is
rotational, and is such as would be produced upon a cube resting on a
rigid support and affected by an inclined force, with or without the co-
operation of lateral forces in the plane of support.

=Z=^

Figure 22. — Deflection of Cleavage by Grit.

The theory of finite strain in viscous plastic masses shows that rota-
tional strains of this description should be accompanied by the develop-
ment of a cleavage. The grain of a mass thus distorted should have an
absolutely constant direction parallel to the plane of support and per-
pendicular to the line of force. Elongation should, in general, take place
in the direction of the grain, and contraction at right angles to the grain
on the cleavage plane. When, however, the force makes no angle with
the plane of support there should be no distortion in the plane of cleav-
age. There should also in all cases be a second direction of elongation
perpendicular to the grain and at a considerable angle to the cleavage
plane.

This theory explains at least most of the characteristics of slate, in-
cluding that of steps. The second elongation just mentioned certainly
exists in some case-*, but I have not data enough to assert its universality.
The practical difficulties of fully determining the position of the strain
ellipsoid from a fossil are such that the omission of other observers to

NEW THEORY OF SLATE. 87

note the existence of this elongation dors not seem to me fatal to the
theory. Many observers have obtained satisfactory evidence of elonga-
tion in the direction of the grain of the slate, while few, if any, of them
appear to have sought for another direction of elongation not in the plane
of cleavage.

The theory here advanced has the advantage of being based on some
of the best-established facts of natural philosophy and of connecting-
cleavage in the most intimate and definite manner with schistosity, joint-
ing, faulting, and systems of fissures. It also exhibits the cleavage of
slate and the master joints, which usually intersect the cleavage planes
at very large angles, as two features of a single strain.

Neither Hooke's law nor any other exterpolated generalization has
been employed in reaching conclusions as to the origin of slaty struc-
ture. Poisson's hypothetical solid was assumed only in an example
in order that the formulas might receive a numerical and geometrical
illustration.

Summary.

The studies here presented are an outgrowth of field-work in the Sierra
Nevada of California. That range is intersected by faults, joints, schis-
tose and slaty cleavages to such an extent that, on a scale of one mile
to the inch, their average separation would be for the most part micro-
scopic. In many areas thes< ■ < ly i tamic manifestations are very systematic.
Such of them as can be considered as concomitants of infinitesimal
strain have been treated in a former paper. In a great proportion
of cases, however, the strains have been finite. Only such areas are
here considered as may be regarded as uniformly affected by finite
strains.

In the first portion of the paper finite strain is considered from a
purely kinematical standpoint. The subject is treated rather fully be-*
cause, for the purpose in hand, it is needful to take an extended view
of the possibilities. The most important topic is that of the planes of
maximum tangential strain and the manner in which they range rela-
tively to the material of a solid which is undergoing strain.

The relations of stress to strain are next sketched, the nature of a
finite shear is elucidated, and Hooke.'s law is examined. Hooke's law
is shown to differ from the statement that '-stress is proportional to
strain" when the deformations are finite. Viscosity, flow, plasticity,
ductility and rupture are defined, and the relation of plastic solids to
fluids is explained.

XIII— Bull. Gkol. Soc. Am., Vol. i, 1892.

88 G. P. BECKER — FINITE STRAIN IN HOCKS.

The conclusions reached are then applied to cases such as may arise
in geology. Large masses of rocks, it is assumed, may be considered as
homogeneous. Were it necessary to take into consideration the minute
texture of rocks, any general conclusions as to their behavior under
orogenic stress would be impracticable. Simple irrotational .pressure is
first taken up. It is shown that such a pressure will produce two sets
of fissures crossing one another at angles approaching 90° if the rock is
brittle. If it is plastic, two sets of schistose cleavages will replace the
fissures. The line of force bisects the obtuse angles of the cracks or
cleavages. Use is made of the theory of this case to prove in a very
simple manner why mica scales and flat sand grains tend to arrange
themselves parallel to the bedding of sedimentary rocks, and why flat
pebbles in water-channels " shingle up stream."

A mass resting on a yielding foundation and subjected to an inclined
force is briefly discussed. This case closely approaches that of the
simple irrotational pressure. It seems to account for unsymmetrical
schistosity.

The most interesting case is that of a mass resting upon a rigid founda-
tion and affected by a force inclined to the foundation at any angle. It
really includes the case of the simple irrotational pressure. If the mass
is brittle and is strained so gradually as not to bring viscosity into play,
the material will rupture in columns, the axes of which are parallel to
the fixed plane of support and at right angles to the force. If the strain'
is so rapidly produced as to excite viscosit}^, only one set of fissures will
form, and these will be intermediate in direction between the line of force
and the projection of the force on the fixed plane. If the rock is plastic
(or if it is kept strained between the elastic limit and the breaking point
sufficiently long to undergo considerable deformation) the fissures inter-
secting the angle between the line of force and the fixed plane will be
replaced to a greater or less extent by cleavage planes; and if the force
• does not approach the vertical to the fixed plane, these cleavage planes
will preserve a nearly constant direction and have a slaty character. In
this case the second set of planes of motion, if they receive expression at
all. will cut sharply across the cleavage planes as master joints. This
seems to be the only way in which slate-like structure can result from
the action of force on homogeneous matter.

The spacing of fissures formed, by inclined pressures is discussed on
the hypothesis that they are so disposed as to lead to the greatest depo-
tentialization of energy. This leads to an exceedingly simple formula
for the thickness of a column in a direction perpendicular to either pair
of bounding planes. The formation of a single system of parallel fissures

SUMMARY. 89

and the existence of undistributed faults are shown to arise in particular
cases of the formula. This formula is applicable only when the rupture
is not brought about by a very rapid strain. When the strain is impul-
sive it is shown that the interference of vibrations attending rupture
may cause further parallel ruptures. The suggestion is made that thick
slates and flags may possibly be due to plastic deformation attended by
vibrations.

As jointing has been referred to tensile stress, rupture through tension
is discussed. It is shown that curved or broken lines, and not plane
partings, must result; and the columnar structure of lavas receives a
seemingly sufficient explanation.

The last portion of the paper is occupied by a review of the theories
and observations on jointing and slaty cleavage. It is maintained that
joints are always attended by macroscopic or microscopic faults, and that
they are closely allied to slaty cleavage. The ascription of slaty struc-
ture to the presence of deflected mica scales and flattened particles is
pronounced unsatisfactory. Glass, wax and other substances in which
slaty cleavage has been artificially produced can hardly owe their cleavage
to such a distribution of flat particles, while sedimentary rocks in which
the fiat particles are mostly parallel to the bedding do not show slaty
cleavage.

Analysis of certain well-known experiments and of some made for
this paper shows that artificial slaty cleavage is always attended by rota-
tional strains, such as those to which slaty cleavage is ascribed above.
The theory of this paper (that slate is due to pressures inclined at small
angles to the cleavage plane and standing at right angles to the grain of
the slate) is shown to account for grain, " side " and " end," for elongation
of fossils in the direction of the grain, contraction in the cleavage plane
at right angles to the grain, and for master joints which intersect
the cleavage plane along the grain and make a large angle with this
plane.

The most important result of the investigation is that jointing, schis-
tosity and slaty cleavage all imply relative movement, and are thus as
truly orogenic as faults of notable throw. They may all be regarded ns
orogenically equivalent to distributed faults. The great number of joints
and planes of slaty cleavage compensates for the minute movement on
each, and the sum of their effects is probably at least as important as
that of the less numerous faults of sensible throw.

In the light of this conclusion it appears that if one could reproduce
the orogenic history of the Sierra in a moderate interval of time on a
model made to a scale of one mile to the inch, it would seem to yield

90 G. F. BECKER — FINITE STRAIN IX ROCKS.

to external and bodily forces much like a mass of lard of the same
dimensions*

* I desire to express my thanks to Professor R. S. Woodward, of the i oast and Geodetic Survey,
for his kindness in reading this paper in manuscript and for giving me the benefit of his advice.
This is not. the first time I have had the advantage of Professor Woodward's profound knowledge
of physics and keen scientific judgment.

Washington, D. C, July 1, ISO.'.

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA
Vol. 4, pp. 91-118 February 21, 1893

THE THICKNESS OF THE DEVONIAN AND SILURIAN ROCKS

OF CENTRAL NEW YORK

BY CHARLES S. PROSSKR

(Presented before the Society August 16, 1892)

CONTENTS

Page

Introduction ill

Records of the Wells 92

Binghamton Well and Section 92

Norwich Well and Section 94

Morrisville Well and Section 95

Chittenango Well and Sect ion 97

Utica (Globe Woolen Mills) Well and Section 100

Campbell Well and Section 101

Syracuse (State) Well and Section 101

Greenpoint (Gale) Well and Section 103

Tully Well Number 2, 1) Group and Section 104

Fulton Well and Section 105

Sandy Creek Well Number 4 and Section 100

Watertown Well and Section 107

General geologic Section of central New York 108

Composite Section 108

Review of I >ata used 108

Generalized geologic Secti< >n 110

Review of Authorities 110

Comparative Sections of eastern, central and western New York 118

Introduction.

The discovery in commercial quantities of natural gas and oil in the
Trenton limestones of Ohio and Indiana led to the drilling of numerous
test-wells in other states that were underlain by this formation. The
attention of prospectors was early directed to New York state as a promis-
ing field, and in the spring of 1887 a test-well was drilled in central New

XIV— Bull. Gkol. Soc. Am., Vol. 4, 1892. l'" '

92 C. S. PROSSER DEVONIAN AND SILURIAN ROCKS.

York, near Morrisville, Madison county. At that time the writer, who
was an instructor in the geological department of Cornell university,
recognized the value of the data that might be obtained from these well
records in giving the thickness and dip of the various terranes composing
the series of New York rocks. During the remainder of 1887 and the
years of 1888-'89, when test-wells were being drilled at numerous localities
in New York, various wells were visited personally and arrangements made
with the owners and drillers for securing reliable and complete sets
of samples. As a result of these efforts, a large amount of data con-
cerning the thickness of the New York geologic formations has been
obtained, and two papers describing the sections along the meridians of
Cayuga lake and the Genesee river have been published*

In the present paper it is intended to describe another of these general
sections crossing the state in a north-and-south line. The section selected
is the one containing the record of wells drilled at Binghamton, Nor-
wich, Morrisville, Utica, Chittenango, Tully, Syracuse, Fulton, Sandy
Creek and Watertown, and as it is approximately along a line somewhat
east of the 76th meridian, with one-half of its length following the Che-
nango river valley, it may very appropriately be' designated the section
of Central New York.

Records of the Wells.

Binghamton Well and Section. — The southernmost well of this series,
which is first to be considered, is one drilled at Binghamton, Broome
county, New York. This well is located on the farm of ex-Sheriff Brown,
one-half mile south of the Susquehanna river and about ten rods from
the southeastern corner of the city limits. It was reported by Mr G.
M. Kepler as on the hillside about 70 feet above the city proper, which
would make its elevation about 940 feet above tide.f

The oeolooic horizon of the mouth of the well is in the Chemung sta^e,
but not at its summit, which is considerably higher. Vanuxem stated
that " the Catskill group covers the highest grounds on the south side
of the Susquehanna [river]. "J Personal examination in this region
shows that Vanuxem was inclined to make the base of the Catskill too
low, and that Chemung fossils occur in what he called Lower Catskill.
The general order of the faunas and formations of the Chenango valley

*The Thickness of the Devonian anil Silurian Rocks of Western Central New York. Am. Geol.,
vo'. vi, October, 1890, pp. 199-2] 1 .

The Thickness of the Devonian and Silurian Kocks of Western New York, approximately
along the line of the Genesee river. Proc. Rochester Acad. Science, vol ii, May, 1892, pp. 49-104.

tThe altitude of the X. Y., L. E. and W. R. II. station at Binghamton i- state, I by Gannett to be
80S feet (Bull. U. S. Geol. Surv., no. 76, p. 52).

IGeol. New York, part iii, 1S4:>, p. 29G.

BINGHAMTON WELL AND SECTION. 93

section from the Hamilton stage up into the Upper Catskill has been
well described by Professor H. S. Williams*

The Binghamton well was drilled during the fall of 1887 and the winter
of 1888 by Mr G. M. Kepler, superintendent of the East Pennsylvania
Oil and Gas company, to whom the writer is indebted for a series of
specimens illustrating its geologic section, as well as to the driller. Mr C.
W. Henderson, for valuable information in reference to this well.

SECTION OF WELL AT BINGHAMTON, NEW YORK.

Approximate altitude, OJfi feet.

Depth. Thickness.^ Kind of rock. Formation.

Feet. Feet.

5d 100 Bluish gray argillaceous shale Chemung and Portage.;

150 100 < Srayer and more arenaceous

250 100 Bluish argillaceous shale "

35

it ><

50 200 Bluish finely arenaceous shale

550 150 < rrayish and blue arenaceous and argilla-
ceous shales

700 50 Grayish finely arenaceous chips, with

fragments of f< >ssils and calcite crystals . "

750 50 i trayish arenaceous shale " "

800 50 Arenaceous and somewhat calcareous;
some of the chips have a brownish-red
tint

*Proc. Am. Assoc. Adv. Sci., vol. xxxiv, 1886, Chart of "Meridional Sections of the Upper De-
vonian Deposits of New York, Pennsylvania and Ohio,': section no. ix.

fFrom this well samples of the drillings were saved from each additional fifty feet of depth ;
consequently it does not follow that each lithologic zone has the exact thickness assigned to it in
this column.

Jin this well-record it is impossible to draw a dividing line between the Chemung and Portage
stages; therefore the rocks composing them are classed together under the heading of Chemung
and Portage. The Portage stage might be divided into Upper Portage, Oneonta sandstone and
Lower Portage. The above division of the Portage would agree in a general way with that of Dr
H. S. Williams as shown on section ix (Chenango) of Ids " Meridional sections of the Upper Devon-
ian of New York, Pennsylvania and Ohio" (Proe. Am. Assoc Adv. Sci , vol xxxiv). In discussing
the " classification of the geologic deposits " the Professor wrote : " The Catskill deposits [Oneonta
sandstone] of Chenango and Otsego counties are intrinsically not distinguishable from the upper
stage of the Catskill, but appear at a lower position stratigraphieally in the interval occupied by
the ' Ithaca group ' of the Cayuga section and by the middle part of the Portage group of the
Ge„esee section" (ibid., p. 234). Also, "the interval occupied in the Genesee section by the typical
Portage fauna is . . . in the Chenango and Unadilla section . . . filled by a preliminary:
stage of the Catskill [Oneonta sandstone]" (ibid , p. 233).

Professor Hall in 1885 said : -The Oneonta sandstone in Otsego and Chenango counties is suc-
ceeded directly by strata bearing fossils of Chemung age," arid his correlation of the Upper De-
vonian was as follow s :

■■ Catskill group.

Chemung group.

^ _x„ ( Portage croup.

Oneonta i Hamilton (upper).

Hamilton group "
(Geol. Surv. N. Y., Palaeontology, vol. v, pt. i, Lamellibranchiata, ii, p. 518).

u u

04 C. S. PROSSER — DEVONIAN AND SILURIAN ROCKS.

Depth. Thickness. Kind of rock. Formation.

Feet. Fed.

850 50 Blue arenaceous shale Chemung and Portage.

900 LOO Arenaceous chips, which arc mainly of a

brownish-red color, a few gray ones. . .

1,000 200 Dark gray arenaceous shale. (Thesample
from 1,150 feet is similar to the upper
part of the Norwich well) "

1,200 :;•">(> Bluish argillaceous shale " "

1,550 400 Mainly gray to bluish arenaceous shale;
si mie dark gray argillaceous shale

1,950 50 Fine chips of brownish-gray finely arena-

ceous material ; slight effervescence . . .

2,000 50 Light gray finely arenaceous sandstone (?)

2,050 200 Bluish argillaceous shale with some arena-
ceous chips ; streak white, non-calcare-
ous Place of Genesee ?

2,250 50 Very fine dark blue chips, which imme-
diately effervesce strongly in cold HC1
and are evidently from a strongly cal-
careous stratum ; possibly the Tully
limestone Tully ?

2,300 50 Blackish argillaceous shale, somewhat
calcareous; streak brown, like Hamil-
ton Hamilton ?

2,350 50 Gray argillaceous shale; streak white,

strongly calcareous Hamilton.

2,4:00 150 Gray argillaceous slightly arenaceous
shale ; streak white

2.550 50 (.ravish arenaceous sandstone and blue
argillaceous shale, strongly calcareous;
fragments of fossils, one Spirift ra f "

2,600 4DO Grayish and bluish argillaceous and

arenaceous shales and sandstone (?). . . "

3,000 117 Gray arenaceous chips with fragments of

fossils and calcite crystals

3,117 Dark gray arenaceous chips which are

strongly calcareous. Bottom of well . . "

Norwich Well and Section— The next well-record to be considered is
that of one drilled near Norwich, Chenango county, about thirty-five
miles northnortheast of Binghamton. The well was drilled by Mr A. W.
McQueen in 1887-'88, who kindly favored me with its record and a set
of samples. Natural gas was found at various horizons down to 1,200
feet, but in such small quantities that it would burn but a few hours
before being exhausted.

NORWICH WELL AND SECTION. 95

SECTION OF THE NORWICH WELL.

Approximate altitude, 1,000 feet.

Depth. Thickness. Kind of rock. Formation.

Feet. Feet. •

50 25 Dark gray or bluish-gray arenaceous shale;

non-calcareous < >neonta of Conrad.

75 50 Mostly argillaceous shale, but part of the

chips are from a fossiliferous layer which
contains Spirifera mesacostaMs, Hall (?) .... Portage.

125 50 Bluish gray arenaceous chips "

175 75 Chips, very fine, and of a dull gray color,

non-calcareous ; " Sherburne sandstone ". "

250 200 Dark gray and greenish gray argillaceous

and arenaceous shales ; " fresh water and

gas at 384 feet "

450 170 Bluish argillaceous shale, non-calcareous;

probably Hamilton Hamilton (?).

020 65 Gray shale, quite calcareous and rather arena-

ceous, with mica ; must be Hamilton .... Hamilton.
685 190 Lithology same as above, slightly calcareous,

" gas pocket " of driller "

875 585 Dark gray arenaceous shale, slightly calcare-
ous ; fossils at 1,020 feet ':

1,460 190 Bluish argillaceous shale, quite calcareous,

fossils ; Clionetes scitula, Hall (?) ■ "

1,650 400 Dark gray argillaceous and arenaceous shales "
2,050 185 Very dark blue to blackish shale ; streak-
white, non-calcareous "

2,235 99 Very dark almost black argillaceous shale

with brownish white streak, non-calcare-
ous ; Marcellus shale or black band in the

Hamilton Marcellus (?).

2.:;:!4 Black argillaceous shale, non-calcareous,
brown streak ; true Marcellus. Bottom of
well Marcellus.

This well begins in the Lower Portage, Oneonta group of Conrad or
the Paracyclas Virata stage of the Hamilton fauna, as named by Dr H. S.
Williams,* and terminates in the Marcellus. The Hamilton is shown to
have a probable thickness of from 1.615 to 1,785 feet, which is the most
important fact furnished by the record of this well.

Morrisville Well and Section. — In- the spring and summer of 1887 the
first test-well was drilled in central Xew York at Eagle ville, about- one
mile south of Morrisville, Madison county, and twenty-live miles slightly

*See Prosser in Proc. Am. Assoc. Adv. Sci., vol. xxxvi, 1887, p. 210.

9G <'. S. PROSSER — DEVONIAN AND SILURIAN ROCKS.

west of north of Norwich. This well begins in the lower half of the
Hamilton stage at an altitude of probably more than 1,200 feet, and
was drilled to a depth of 1,889 feet, terminating near the bottom of the
Onondaga Salt group.

SECTION OF THE MORRIS VILLE WELL.*
Approximate altitude, 1,200 (?) feet.
Depth. Thickness. Kind of rock. Formation.

Feet. Feet.

340 31+ Pure argillaceous black shale with

brownish-black streak Marcellus shale.

371 93 Dark and light gray limestone, which

effervesces very strongly in cold II CI. Upper Helderherg (Cor-

niferous) limestones.
Place of Oriskany (?).
404 180 Dark gray limestone, mixed with

some quartz grains, which are prob-
ably from the Oriskany sandstone
above. The dark gray strongly calca-
reous limestone continues clown to
028 feet, where a very light gray calca-
reous sample was obtained. At 578
feet a pocket of gas was struck which

burned for a short time Lower Helderberg.

050 125 fA dark gray limestone, which effer-

vesces more slowly in cold IIC1 than
the samples above, and leaves a large
residue of argillaceous material ; gas

in small amount at 755 feet Onondaga Salt group {'!).

775 185 Mainly dark gray limestone, but alter-

nating with light gray to drab lime-
stone ; effervescence usually moder-
ately strong in cold HC1, leaving large

residue; frequently grains of selenite . Onondaga Salt Group.
900 58 Greenish-gray shale, which has a slight

effervescence in cold HO "

1,018 5 Chocolate-colored shale; slight efferves-
cence in warm HC1

1,023 87 Greenish shale; slight effervescence in

warm HO

1,110 09 Dark gray to blackish marlite, which

effervesces quite readily in cold li( '1 . "

*Thiswell was described l>y Prosser in Proc. Am. Assoc. Adv. Sci.,vol. xxxvi. 1887, pp. 208, 200.

■f-The sample from 619 feet is a dark limestone, [earing a considerable argillaceous residue, with
some grains of selenite (?), and hears a strong resemblance i" the upper part of the ' >nondaga Sail
group. However, the light colored, strongly calcareous sample from 628 feet makes it appear
probable that it is better to consider the Onondaga Salt group as beginning at about C50 feet.

1,300

100

1,400

60

1,460

105

1,565

225

1,790

25

(1

«

MOKRISVILLE WELL AND SECTION. 97

Depth. Thickness. Kind of rock. Formation.

Feet. Feet.

1,179 36 Bluish-gray marlite, which is quite cal-
careous Onondaga Salt group.

1,215 -44 Dark gray to drab impure limestone or

marlite ; effervesces strongly in cold

HC1

1,259 41 Dark gray to drab marlites mixed with
crystals of salt. The driller reported
10 to 12 feet of rock-salt at 1,259 feet ;
also chocolate and green shales

Chocolate' and green variegated marls,
with a little bluish shale . . . "

Mostly chocolate shale, with an occa-
sional green and blue chip "

Mostly green and bluish marls, with an
occasional red chip

Clear red shale, with an occasional green
chip

Blue argillaceous shale, slightly calcare-
ous ; small amount of salt from evap-
oration about the cork of the vial. " "
1,815 5 Drab gray limestone or marlite ; effer-
% vesces readily in cold 1IC1, but leaves
a large residue ; salt as in sample
above

Dark blue argillaceous shale and mar-
lite

Dark blue limestone, which has a strong
effervescence in cold HC1 " "

The last sample, from 1,889 feet, is partly
limestone, but contains more blue
argillaceous shale. Bottom of the
well in the Onondaga Salt group*. . . " "

Chittenango Well and Section. — A well which has furnished an important
section for the purposes of this paper was drilled during' the first half of
1890, at Chittenango, Madison county. Mr F. W. Lamphere, of that vil-
lage, carefully preserved a complete set of samples from this well, with
an accurate record of their depths, which eventually reached me for ex-
amination. Chittenango is seventeen miles northwest of Morris ville,

*In the preliminary record of this well it was reported that possibly the Niagara was reached at
1,805 feet and the Clinton at 1,87-1 feet (Prof. Am. Assoc. Adv. Sci , vol. xxxvi, pp. 20S-209). A com-
parison of the samples from this well with those of the Chittenango and other wells convinces me
that the Morrisville well did not reach the Clinton stage, but probably ceased near tin" bottom of
the Onondaga Salt group. The driller at l.sso feet reported the Clinton iron ore ami stated that
"slight impressions of lenticular grains, about the size of a pin-head, oval and apparently of a con-
cretionary nature, were seen." It is probable that some, other substance must have been considered
iron ore, as the samples from 1,879 feet and 1,884 feet do not indicate its presence.

1,820

54

1,874

15

1,889

98 C. S. PROSSER DEVONIAN AND SILURIAN ROCKS.

and the well is located in the western part of the village, on the bank
of the Chittenango creek. The Chittenango station of the New York
Central and Hudson River railroad is 417 feet ahove tide, and, baro-
metrically, the mouth of the well is about 27 feet higher, making the
altitude approximately 444 feet above tide. Natural gas in small quan-
tities was obtained at several horizons. A little gas was struck at a
depth of 950 feet in the Medina. The largest amount occurred in the
Trenton limestone at a depth of 2,651 feet, hut gas was reached at 2,690,
2,875, 2,884 and 2,904 feet. At fi rs1 , aft< r 1 >ei ng closed for thirty minutes,
there was a sufficient volume of gas to produce a pressure of 25 pounds
to the square inch, hut by the middle of August, 1890, it had decreased
to 12 pounds.

SECTION OF THE OHITTENANGO WELL*

Approximate altitude, IfJ^jeel above tide.

Depth. Thickness. Kind of rock. Formation.

Feet. Feet.

182 24 Bluish and grayish chips mixed with

reddish dirt Drift (?).

20G 179 Bluish marlite, which effervesces quite

strongly in cold HC1 "

385 5 Mostly chocolate-red marlite with some

greenish and a few gypsum chips. . . . Onondaga Salt group.

.'590 10 Bluish marlite with some red and

green shale " "

400 34 Clear reddish-chocolate shale with just

a few green chips " "

434 11 Mottled chocolate and green shales. .. .

445 16 Green shale with a few reddish chips. . " "

461 54 Dark gray and bluish-gray limestone,
which effervesces rather slowly at
first in cold HC1, hut hecomes strong
on standing. The samples leave a
considerable residue. Occasionally
some red and green chips ; at 500 feet
grains of salt

515 52 Bluish-gray and bluish-black limestone
with some pinkish chips ; strong effer-
vescence in cold HC1 Niagara (?).

567 •"-'! Green argillaceous shale, generally non-
calcareous ( Jlinton.

600 44 Bluish-gray shale, which is slightly cal-
careous and arenaceous "

*The record of this well is based upon a set of specimens purchased by the United States Geo-
logical Survey and now deposited in the United States National Museum.

f'HITTENANGO WELL AND SECTION. 99

Depth. Thickness. Kind of rock. Formation.

Feet. Feet.

644 11 Dark gray and rather pinkish chips,
which effervesce strongly in cold HC1
and contain hematite ii-on ore ; some
greenish, argillaceous, non-calcareous
shale Clinton " iron-ore bed."

655 225 Green argillaceous shale, non-calcare-

ous ; brachiopod shells at 800 feet. . . Clinton.

880 10 Greenish to greenish-gray chips, not so

argillaceous and scarcely calcareous ;
a few reddish chips like iron ore .... "

890 12 Greenish quartzitic chips mixed with
green argillaceous shale ; a good many
white, vitreous, angular chips that are
apparently quartz grains Medina.

902 4 Mainly chocolate-red chips of sand-

stone (?) mixed with white quartz

grains " Gray band " (?) of Me-

dina.

906 48 Greenish argillaceous shale and sand-
stone mixed with white vitreous
grains of quartz Medina.

954 456 Mainly brownish-red quartzose sand-

stone, with some greenish-gray sand-
stone and argillaceous green shale ... "
1,410 107 Greenish-gray quartzose sandstone,with

some bluish shale Oswego sandstone.

1,517 640 Mainly blue argillaceous shale, with

some bluish-gray arenaceous shale or

sandstone Lorraine or II u <1 s o n

shale.
2,157 233 Blackish argillaceous shale ; streak

slightly brownish Utica shale.

2,390 60 Blackish argillaceous shale, with brown
streak, but mainly gray calcareous
chips ; at about the top of the Trenton
limestone " "

2,450 50 Clear sample of dark blue limestone ;
strong effervescence in cold HC1 ;
undoubted Trenton Trenton limestone.

2,500 390 Dark gray and light gray limestone,
with some dark blue limestone,
steongly calcareous ; fossils, brachio-
pods (Orthis ?), at 2,600 feet ; brachio-
pods at 2,710 feet Trenton.

2,890 88 Moderately dark gray limestone ; fair
effervescence in cold HC1, but con-
taining a large amount of non-calcare-
ous material (argillaceous?) "

XV— Rurx. Geoi,. Soc. Am., Vol. 4 1892.

100 C. S. PEOSSER DEVONIAN AND SILURIAN ROCKS.

Depth. Thickness. Kind of rock. Formation.

Feet, Feet.

2,978 4s._l Lightish gray, with some dark gray
magnesian limestone; effervescence
very slight in cold HC1, hut becomes
strong on heating Trenton.

3,0262 Bottom of well.

The well begins in the colored marls of the Onondaga Salt group, and
reaches the Clinton at a depth of 567 feet. The thickness of the dif-
ferent stages in this well is as follows: Clinton, 323 feet; Oneida con-
glomerate, 12 feet; Medina sandstone, 508 feet; Oswego sandstone, 107
feet ; Lorraine shales and sandstones of the Hudson series, 640 feet ;
Utica shale, 233 feet, and penetrates the Trenton limestone to a depth
of 636* feet.

Utica {Globe Woolen Mills) Well and Section. — A well was drilled by the
Globe woolen mills to the depth of 1,720 feet in the city of Utica, near
the level of the Erie canal, and the samples were kindly placed at my
disposal for study by Mr Charles D. Walcott, of the United States Geo-
logical Survey. This well is about thirty-one miles east of Chittenango
and twenty-five northeast of Morrisville.

SECTION OF THE GLOBE WOOLEN MILLS WELL AT UTICA, NEW YORK.

Approximate altitude, J+28 feet.

Depth. Thickness. Kind of rock. Formation.

Feet. Feet,

370 200 Clear, black argillaceous shale with brownish

streak, slightly calcareous Utica shale.

570 330 Dark blue limestone ; strong effervescence in

cold HC1 ; fragments of fossils at 650, 810
and 850 feet ; fragments of brachiopods at

730, 750, 790 and 830 feet Trenton limestone.

900 180 Drab to bluish-gray massive limestone, which
effervesces strongly in cold HC1, and light
gray, glistening limestone, which does not
effervesce strongly in cold HC1 " "

1 ,080 180 Light gray powder, which is strongly calcare-
ous ; very marked effervescence in cold
IIC1 Calciferous (?).

1,260 140 Slightly brownish-gray sample, composed
largely of white vitreous quartz grains with
some mica grains ; non-calcareous Calciferous.

1,40!) 320 Mainly light gray samples, composed chiefly

of white or vitreous quartz grains; some
are of slightly brownish color, and part of
the samples are quite badly iron-stained. . Potsdam (?).

1,720 Bottom of well.

CAMPBELL AND SYRACUSE WELLS AND SECTIONS. 101

Campbell Well and Section. — Very interesting for comparison with this
well is the record of the Campbell well, three miles west of Utica, which
was drilled to a depth of 2,250 feet. This well was described by Mr
Charles D. Walcott in August, 1887,* and through his courtesy the
writer has had the pleasure of studying the set of samples saved from
it. The record of this well as reported by Mr Walcott may be briefly
summarized as follows :

SECTION OF THE CAMPBELL WELL NEAR UTICA, NEW YORK.

Formation.

Lorraine shale of the Hudson group..

Utica shale.

Trenton limestone.

( rap of 180 feet between the Trenton and Calciferous, 100 feet of
which probably belongs»to the Calciferous, which would make
the top of the Calciferous at about 1,230 feet.

Calciferous and arenaceous strata, 260 feet ; Calciferous in all about
360 feet in thickness.

Potsdam.
100 -f- Pre-Cambrian and Archean.

The careful study of the Campbell well record and specimens has fur-
nished much assistance in interpreting the record of the Utica well. The
top of the Trenton limestone is reached at a depth of 570 feet in the
Utica well and at 800 feet in the Campbell well, a difference of 230 feet.
Supposing the formations to have about the same thickness, then the
top of the Calciferous might be expected at a depth of about 1,000 feet,
and the light gray, strongly calcareous rock, which is considered as rep-
resenting the Calciferous, occurred at 1,080 feet. In the same manner
the top of the. Potsdam would be reached at about 1,360 feet, while the
sample which is regarded as probably coming from near the top of the
Potsdam was reached at a depth of 1,400 feet, and the bottom of the well,
at a depth of 1,720 feet, is still in this formation, the Archean not having
been reached.

The line of separation between the Trenton limestone and the Cal-
ciferous is somewhat difficult to determine, and it is especially so between
the Calciferous and Potsdam. The point at 1,400 feet, indicated as the
beginning of the Potsdam, can only be taken as probably near the line
of separation between these two formations.

Syracuse (State) Well and Section. — In 1884 the "state well" was drilled
at the southern end of Onondaga lake, near Syracuse, about fifteen miles

*Proe. Am. Assoc. Adv. Sci., vol. xxxvi, pp. 211, 212.

I><pt It.

Thickness,

Feet.

Feet.

90

!I0

710

800

350

1,150

1,330

2(11)

1,590

410

2,000

100 4-

2,100 +

102 C. S. PROSSER DEVONIAN AND SILURIAN ROCKS.

west of Chittenango. The altitude of Onondaga lake is given* at 361 feet,*
so that the altitude of the mouth of the well may be called approximately
365 feet. This well was drilled to the depth of 1,965 feet. One hundred
and seventy-five samples were saved and the record of the well was pub-
lished by Dr F. E. Englehardt in 1885.f

Later Dr Englehardt kindly donated this set of samples to the United
States National Museum and the writer has carefully examined the
entire collection.

SECTION OF THE STATE WELL NEAR SYRACUSE, NEW YORK.

Approximate altitude, 365 feet.
Depth. Thickness. Kind of rock. Formation.

Feet. Feet,

430 25 Reddish, grayish, white and brownish-

red quartz grains, with pebbly material . Drift,

455 100 Chocolate-colored marl, slightly calca-
reous Onondaga Salt group.

555 23 Green argillaceous shale or marl, slightly

calcareous " "

578 332 Bluish shaly limestone ; dark gray, glis-
tening limestone, which effervesces
very strongly in cold HO ; drab and
almost black shaly limestone Niagara limestone.

910 98 Green argillaceous non-calcareous shale,

with greenish-gray limestone. At 995
feet oolitic iron ore with green shale. . Clinton.
1,008 38 Grayish and brownish arenaceous chips,

very slightly calcareous at 1,008 feet,
which may probably be regarded as
the upper part of the Medina. Below
this grayish and whitish quartz grains
with a little greenish, argillaceous and

arenaceous shale Medina,

1,046 769 Slightly brownish-red and greenish sili-

cious sandstone at 1,046 feet, Below

this white, pinkish and greenish ,
quartz grains, some greenish shale, but
chiefly brownish-red silicious sand-
stone ; also some greenish-gray sili-
cious sandstone Medina, S07 feet thick-

1,815 150 Greenish-gray silicious sandstone and

shale,with some blue argillaceous shale. ( )swego sandstone.
1,965 i Bottom of well " "

♦Geological map of Onondaga county, in Ann. Rep. Supt. Onondaga Salt Springs for 1884.

flbid., pp. 15-17.

J The depth of sample 175 is marked as 1,965 feet, but Dr Englehardt gives the depth of the well

j The

1,9G9

as 1,969 feet. (Ibid., p. 17.)

GREENPOINT (GALE) WELL AND SECTION. 103

The above interpretation agrees very closely with the correlation of
the section which was made by Dr Englehardt. The Doctor gives the
top of the Niagara limestone as at 578 feet, which is the same as for my
section. The top of the Clinton, which is at 910 feet, is not stated, but
of course the iron-ore stratum was noticed and correctly placed in the
geologic series. At 1,008 feet are grayish and brownish arenaceous
chips, which the writer is inclined to refer to the Medina, although Dr
Englehardt considered a " red-brown sandstone " at 1 075 feet as the top
of the Medina. Finally, at 1,815 feet is the top of the Oswego sandstone,
in which formation is the bottom of the well.*

Greenpoint (Gale) Well and Section. — The "Gale " well at Greenpoint, on
the eastern shore of Onondaga lake, about four miles north of Syracuse,
was drilled in 1884 to the depth of 1,G00 feet. This well section was also
described by Dr Englehardt,f and the specimens donated to the United
States National Museum. The writer has examined the set of samples,
and would give the section as follows :

SECTION OF THE GALE WELL NEAR SYRACUSE, NEW YORK.
Depth. Thickness. Kind of rod-. Formation.

Feet. Feet:

65 457 Chocolate-red, green, blue and dark gray

shales and marls Onondaga Salt group.

522:}: 320 In the upper part blue calcareous shales
or shaly limestone, and below very dark
gray to blackish, glistening limestone;
some of the samples dark blue, part with
strong effervescence in cold HC1, and
the remainder with slight effervescence,
which is increased on heating ; the lower
part is largely blue shaly limestone ;
fragments of brachiopods and lamelli-
branchs at 700 feet Niagara (?)

•S42 149 Mainly clear, green argillaceous shale ; at
970 feet some iron ore, more at 971 feet,
and sample from 970 feet largely com-
posed of oolitic iron ore ; at 98(5 feet
dark gray shales with some slightly red-
dish chips Clinton.

♦ Compare Dr Englehardt's section in ibid., pp. 5-17, and especially the general account of the
will following the section on page 17.

t Ibid., pp. 12-ir».

I Dr Englehardt called the top of the Niagara limestone 527 feet, but the pre ling sample from

522 feet varies but little in lithologie characters. PossiMy it would be better to call 536 feet the top
of the Niagara, where the first of the dark blue limestone occurs.

Depth.

Thickness.

Feet,

Feet.

991

583

104 0. S. PROSSER DEVONIAN AND SILURIAN ROCKS.

Kind of rod:. Formation.

Brownish-red arenaceous shale and sili-
cious sandstone, alternating with dark
gray, bluish-gray sandstone and olive

and greenish shale Medina.

1 ,.i74 * Bottom of well in the red Medina sand-
stone "

Dr Englehardt stated : " I cannot well establish the depth at which
the Niagara group passes into the Clinton group below,"* but it seems
pretty certain that the green argillaceous shale at 842 feet is in the Clin-
ton, and, further, that ''the passage from the Clinton group into the
underlying Medina group must be about 1,007 feet from the surface
where the first quartz makes its appearance. At 1,020 feet the first sand-
stone 'had been passed through and certainly the Medina sandstone
reached."!

To the writer it seems better to call the brownish-red arenaceous shale
at 991 feet the top of the Medina.

On comparing the record of the State and Gale wells it will be noticed
that in the State well the Niagara group has a thickness of 332 feet and
in the Gale well it is 320 feet. The Clinton is 98 feet thick in the State
well, while in the Gale well 149 feet of greenish shale has been referred
to the Clinton. Possibly this is too great a thickness for the Clinton,
and it certainly seems that there should not be so great a difference in
the thickness of the formation for the two wells. The State well passed
through the Medina, making a total thickness for that group of 807 feet,
and stopped after passing through 150 feet of the Oswego sandstone.
The Gale well passed through 583 feet of the Medina group and ceased
at a depth of 1,574 feet.

Tally Well Number J and Section. — The Solvay Process Company of Syra-
cuse, New York, in 1888 discovered rock-salt in Tully township, in the
southern part of Onondaga county .J More than twenty wells have since
been drilled by this company, the depth to the rock-salt ranging from
974 to 1,465 feet, which is generally between 40 and 50 feet in thickness.||

Through the kindness of Mr G. E. Francis, of the Solvay Process < !om-
pany, the writer has had the satisfaction of studying a set of samples

*The last sample of the set donated to the National Museum is from 1,574 feet, but Or Engle-
hardt gives the total depth of this well as ?,600 feet (Ibid., p. 1 1 1.

t Ibid., p. 15.

JSee Ann. Rep. Supt. Onondaga Salt Springs for 1889, p. 27.

I See ibid, for 1890, pp. 2::-27. A general account of 1 1 1 i — region, together with a brief description
of twenty-one wells, is given in the Mineral Resources of the United States for the years 1889-90
(Washington, 1892), pp, 186, 187.

TULLY WELL AND SECTION. 105

from one of these wells. The well is the one known as No. 2 of the D
group, which is about two and one-half miles northwest of Tally village,
from which samples were saved from every ten feet of depth.

SECTION OF THE TULLY WELL, NUMBER 2, D GROUP.

Approximate altitude. 815 feet above tide*
Depth. Thickness. Kind of rock. Formation.

Feet. Feet.

30 420 Mainly blue argillaceous shale, which
is slightly calcareous and some of it
rather arenaceous ; from 410 to 450 feet
slightly blackish shale with brownish
streak alternating with blue argillace-
ous shale Hamilton.

450 110 Mainly very black argillaceous shale

with brown streak Ma reel 1 us-.

560 260 Bluish shaly limestone ;' strong efferves-

cence in cold HC1 ; also light and dark

gray limestone ; fragments of fossils . . Upper and Lower Hel-

derberg.

820 255 f First bluish-gray, shaly limestone,

which has very slight effervescence in
cold HC1, then mainly dark and light
gray limestones, which have a stronger
effervescence in cold HC1, especially

the light gray chips Onondaga Salt group(?).

1,075 40 Rock-salt Onondaga Salt group.

1,115 Last sample %

Fulton Well and Section. — In the winter of 1887-'88 a test-well was
drilled at Fulton, Oswego county, New York, and through the kindness
of Dr George A. Edwards, of Syracuse, New York, a set of samples was
furnished me for study. Fulton is about twenty-three miles north-north-
west of Syracuse, and the altitude of the mouth of the well is approxi-
mately 287 feet above tide. ||

♦According to Mr G. E. Francis.

fNo indication oi the Oriskany sandstone appears in the samples; consequently it is impossible
to indicate any dividing line between the upper and lower Helderberg limestones. In the same
way the dividing line between the lower Helderberg and the Onondaga Sail group is not clear: but
it has been taken provisionally at ihe point where a bluish gray magnesian limestone appears in
considerable thickness.

X Dr Englehardt reported that this well reached the rock-salt at a depth of 1,075 feet, and that the
stratum was 4:; feet in thickness (Advance sheets of Dr. Englehardt's Rept. to the Supt. Onondaga
Salt Reservation for 1890, p. 8).

||Altitude estimated by Mr Thomas D.Lewis from the number of locks on the Oswego canaJ
between Fulton and Lake Ontario.

100 0. S. PROSSER — DEVONIAN AND SILURIAN ROCKS.

SECTION OF THE WELL AT FULTON, NEW YORK.

Approximate altitude, 287 feet.

Depth. Thickness. Kind of rock. Formation.

Feet. Feet.

42 358 Brownish-red quartz grains and chips of

brownish-red sandstone ; at 215 feet a

few chips. of greenish sandstone. Medina.

400 185 Greenish-gray sandstone, composed largely

of quartz grains, with some greenish to

olive argillaceous shale < >swego sandstone.

58o 695 Mainly blue argillaceous shale, with some

arenaceous shale and a little quartzose
sandstone; arenaceous chips containing

fragments of fossils at 875 feet Lorraine shale of the

Hudson group.

1,280 120 Black shale with brownish streak Utica shale.

1,400 335 Mainly bluish-gray limestone, which effer-
vesces strongly in cold HC1 ; some dark
blue and light gray limestone ; fragments
of fossils at 1,638, 1,665 and 1,735 feet. . . Trenton limestone.
1.735 * Last sample "

This well was first described by Mr Charles A. Ashburner in 1888, who
reported that the well had been drilled to the depth of 1,727 feet, and
gave the following section :

" Medina sandstone 400 feet,

Hudson River shale 880 "

Utica shale and slate 120 "

Trenton limestone 327 "

Total 1,727 "

"At 1,727 feet, 327 below the top of the Trenton limestone, gas was struck in such
force as to throw sand from the well to the top of the derrick, a height of 74 feel
10 inches. The gas caught on tire and the derrick was burned down." f

In April, 1890, Mr ( 'hades D. Walcott published the same record, with
the additional 323 feet to which the well had been drilled, making its
total depth 2,050 feet, X

Sandy Creek Well Number 4 and Section. — Several wells have been drilled
near Sandy Creek and Lacuna, Oswego county. New York, for natural
gas, which was obtained in moderate quantities. Mr Gilbert X. Hard-
ing, of Lacona, saved and forwarded to me a set of samples from well
No. 4 of the Sandy Creek Oil and Gas Company, limited. Lacona is

* This is the depth from which the hist sample came in the set furnished me for study. Mr
Walcott reported that the well was drilled :;i."> feet deeper, reaching a depth of 2,050 feet, and that
it passed through 650 feel of Trenton limestone (Bull. Geol. Soc. Am., vol. i. p. 349).

fTrans. Am. I n-t. Min. Eng., vol. xvi. p. 958.

| Bull. Geol. Soc. Am., vol. i, p. 349.

SANDY CREEK; WELL AND SECTION. 107

forty miles north-northwest of Chittenango or twenty-eight miles north-
east of Fulton.

SECTION OF WELL NUMBER 4, AT SANDY CREEK, NEW YORK.

Depth. Thickness. Kind of rod:. Formation.

Feet. Feet.

50 350 Mainly blue argillaceous shale, but with

some bluish to dark gray, fine-grained

sandstone, which contains fine grains of

mica; segments of crinoid stems at 200

feet Lorraine shale of tbe

Hudson group.
400 145 Blackish argillaceous shale with moder-
ately brownish streak Utica shale.

545 600 Dark blue, dark and light gray limestone

chips, most of which effervesce very
strongly in cold HC1 ; fragments of fos-
sils at 600 and 700 feet; fragments of
brachiopods at 675, 750, 880, 900, 950 and
1,050 feet, and numerous fragments of
well preserved brachiopods at 765, 800,
830 and 850 feet ; gas at 675, 765 and 790
feet. Samples from 545, 830, 880 and

1,030 feet were blown out by gas Trenton limestone.

1,145 Bottom of well in the Trenton limestone.

Walertoton Well and Section. — At Watertown, Jefferson county, 24 miles
north-northeast of Lacona, a well was drilled to the depth of 530 feet by
the Black River Gas and Fuel Company. A little gas was found at the
depth of 253 feet, according to the driller. Mr Albrant, to whom the writer
is indebted for the samples from this well.

SECTION OF WELL AT WATERTOWN. NEW YORK.

Depth. Thickness. Kind of rock. Formation.

Feet. Feet.

92 8 Light greenish, very compact, fine-grained lime-

stone, which effervesces strongly in cold IIC1... Trenton.

100 26 Light gray limestone, strongly calcareous

126 135 Mainly light green limestone, which does not effer-
vesce strongly in cold HC1 at first, but increases
on standing

261 14 Very light gray fine-grained limestone ; effervesces
strongly in cold HC1

275 255 Many pinkish white chips, which are usually non-
calcareous; also dark green and dark gray, the
gray being somewhat calcareous; near the bot-
tom are some vitreous white quartz grains ( lalciferous ?

530 Bottom of well

KVI-Buli-. Geoi,. Soc. Am., Vor.. I, 1892.

108

C. S. PEOSSER — DEVONIAN AND SILl'JUAN ROCKS.

General geologic Section of central New York.

Well.

Depth.

Thirl: in SS

Feet.

Feet.

inghamton.

0

2,250

CD

I _-

iz

Composite Section. — From the preceding well-sections a general section
has been compiled, giving the approximate thickness of the different
formations, together with the total thickness from the Chemung, as ex-
posed at Binghamton, New York, down to the Archean.

Formation.

Mouth of the Binghamton well in the
Chemung. From 900 to 1,000 feet
brownish-red arenaceous chips, prob-
ably the horizon of the "Oneonta

sandstone." At 1,850 feet, about the
mouth of the Norwich well and lower,
the " Sherburne sandstone." Place of
the Genesee shale and the Tully lime-
stone.

Hamilton.

Marcellus shale.

Upper Helderberg (Corniferous .limestone).

Place of Oriskany sandstone.

Lower Helderberg.

Onondaga Salt group.

Niagara.

Clinton.

Medina.

Oswego sandstone.-

Lorraine shale of the Hudson group.

Utica shale.

Trenton.

Calciferous.

Potsdam.

Pre-Cambrian and Archean.

2,250

1,785

4,035

100 (?)

Morrisville . .

4,135

93

4,228

-.-.(?)
1S6 (?)

4,414

1,239 -f

5,653 +

52 (?)

Chittenango.

5,705

323

6,028

520

6,548

107

6,655

640

7,295

233

7.528

637 +

Utica

8,165 4-

320 (?)

8,485

410 (?)

81,895

....

Review of Data used. — It will he interesting to compare the thickness
of these formations with that obtained for them in wells more remote
from the meridian of this section.

The combined thickness of the Chemung and Portage groups was
shown by the Bird Creek well, eight miles southwest of Elmira, to be con-
siderably more than 2,700 feet for that region,* while in the Ithaca well
the Hamilton is 1,142 feet thick : the Marcellus shale, 82 feet; the Upper
Helderberg (Corniferous limestone). 78 feet: Oriskany sandstone, 13
feet; Lower Helderberg. approximately llo feet, and the bottom of the
well is in the Onondaga Salt group after passing through 1,285 feet of
limestone, shale and salt belonging in that group. The Seneca Falls

* Prosser : Am. I teol., vol. \ i. p. '-!"i

REVIEW OF DATA USED. 100

well began in the upper part of this formation and passed through 950
feet before reaching the Niagara limestone*

As near as can be determined, the Niagara limestone has a thickness
of 52 feet in the Chittenango well, while in the State well near Syracuse
it is 332 feet thick ; in the Gale well, 320 feet, and in the Clyde well, 335
feet.f However, it is often very difficult to decide on the dividing line
between the lower gray marls aim limestones of the Onondaga Salt group
and the beginning of the Niagara limestone; hence there is some doubt
as to the accuracy of the thickness of this formation.

The Clinton group has a thickness of 323 feet in the Chittenango well ;
in the State well 98 feet, and the Gale well of 149 feet. There is appar-
ently too. great a difference in the thickness of this formation as given in
the State and Gale wells when their proximity is considered, but the
samples as labeled seem to furnish the above result. The Clinton is
approximately 83 feet in thickness in the Clyde well, and in the Seneca
Falls well the Niagara and Clinton groups have a thickness of 400 feet.'!

The Medina is 508 feet thick in the Chittenango well and 807 feet in the
State well. The Gale well penetrated the Medina 583 feet ; in the Clyde
well it is 942 feet thick, and in the Wolcott well 690 feet. 1 1 The Oswego
sandstone is 107 feet thick in the Chittenango well ; 185 feet in the Fulton,
and in the Wolcott 210 feet. The Clyde well stopped after passing through
92 feet § of it and the State well penetrated it to a depth of 150 feet.

The Lorraine shale of the Hudson group isG40 feet in thickness in the
( '1 littenango well and 695 feet in the Fulton well. The Sandy Creek well
began in the Lorraine, passing through 400 feet before reaching the Utica
shale. In the Wolcott well there is 820 feet of shales and sandstone
which may be referred to the Lorraine and the Utica shale.^[

The Utica shale which forms the surface rock at Utica was shown by
the Globe Woolen Mills well to have a thickness of at least 570 feet in
that city. Mr Walcott reported its total thickness to be 710 feet in the
Campbell well, three miles west of Utica.** This shale is 233 feet thick
in the Chittenango well ; 120 feet in the Fulton, and 145 feet at Sandy
creek. The Trenton limestone in the Utica well has apparently a thick-
ness of 510 feet, but on account of the great difficulty in deciding upon
what shall be considered the top of the Calciferous this statement must
be accepted as partly an estimate. Mr Walcott in a similar manner con-
cluded that the Trenton had a thickness of about 430 feet in the Camp-
bell well.ff The Chittenango well penetrated this formation to a depth
of 637 feet, and in the same way the Sandy Creek well passed through

* II. id., pp. 202-203. r [bid., p. 204. t Ibid-, l'l>- 203, 204.

|| Ibid.', p. 204. g Ibid., p. 204. fl Ibid., p. 204,

**Proc. Am. Assoc. Adv. Soi., vol. xxxvi, p. 212, tt Ibid., p. 212.

110

C. S. PltOSSER — DEVONIAN AX!) SILURIAN ROCKS.

690 feet of Trenton; the Fulton well, 650 feet, and the Wolcott well, 750
feet*

A Generalized geologic Section along the Meridian of the
Chenango river from the Top of the Chemung down to the
Archean.

In order to show the variations in the ahove section as compared with
our previous knowledge of the thickness of these terranes, a general
geologic section ranging through the same series of formations has been
compiled from books and geological articles. In this compilation the
maximum thickness of the terranes, as near the line of section as possi-
ble, has been taken. The notes following the section give the authorities
and references.

Depth.

Thickness.

Authority.

Formation.

Feet.

Feet.

0

2,000

A

Chemung and Portage.

2,000

20

B

Genesee.

2,020

25

C

Tully.

2,045

1,100

D

Hamilton.

3,145

100

E

Marcellus.

3,245

70

F

Upper Helderberg (Corniferous).

3,315

20

G

Oriskany.

3,335

120

H

Lower Helderberg.

3,455

700

I

Onondaga Salt group.

4,155

50 (?)

J

Niagara.

4,205

200

K

Clinton.

4,405

400

L

Medina.

4,805

100

M

Oswego sandstone or Oneida conglomerate

4,905

600

N

Lorraine shale of the Hudson.

5,505

180

O

Utica.

5,685

330

P

Trenton.

6,015

350

Q

Caleiferous.

6,365

410 (?)

II

Potsdam.

6,775

Archean.

Review of Authorities.

Authority and reference for the thickness of the terranes, as given in
the preceding section.

A. — Dr H. S. Williams estimated the thickness of the rocks from the
base of the true Catskill down to the horizon of the Genesee shale or the
top of the Hamilton, for the Chenango valley, as approximately '2.000
feet (Proc. Am. Assoc. Adv. Sci., vol, xxxiv, 1886, Chart on the " Merid-
ional Sections of the Upper Devonian Deposits of New York, Pennsyl-

' Am. Geo)., vol. vi, p. 204.

REVIEW OP AUTHORITIES. Ill

vania and Ohio," section no. ix). On a section crossing the Catskill
range from Schenevus to Glasco, prepared by Professor James Hall, it
was shown that the " Portage and Chemung have a thickness of more
than 2,000 feet" for that region (ibid., vol. xxiv, B, 1876, p. 82).

B. — Prosser noted: "Black argillaceous shales 20 feet in thickness
near Smyrna [in the Chenango valley, in the northern part of Chenango
county "] (ibid., vol. xxxvi, 1887, p. 210).

C. — Prosser reported : " Limestone layers, separated by calcareous
shales, with a total thickness of 25 feet . . . near Upperville, in
Smyrna township." At least part of this series belongs to the Tully
limestone (ibid., p. 210;. Emmons said: "In Albany and Schoharie
counties it [Tully limestone] is unknown. . . . The thickness . . .
is from 12 to 15 feet " (Agriculture of N. Y., vol. i, 1846, p. 186).

D. — Professor Hall wrote : " The thickness of this group [Hamilton]
on the eastern limit of the district [fourth geological district, Cayuga
lake region] cannot be less than 1,000 feet" (Geol. N. Y., pt. iv, 1843, p.
194). Vanuxem said: "The group is of great thickness; in no part
probably less than 300, and swelling to 700 feet" (Geol. N. Y., pt. iii,
1842, p. 151). Professor Dana stated that " the greatest thickness — about
1,200 feet — is found east of the center of the state" (Manual Geology, 3d
ed., p. 266) ; but it is also stated that " the Hamilton strata are 1,000 feet
thick in central New York" (ibid., p. 267). While Professor Hall said,
" The thickness of this group [Hamilton] along the Schoharie creek is
much greater than has been supposed, amounting probably to 3,500 feet "
(Proc. Albany Institute, vol. 1, 1871, p. 133). 1,100 feet seems to be a fair
average for this section, based upon Hall's estimate for Cayuga lake and
Dana's for eastern central New York. Emmons stated: "By estimating
the fossiliferous and non-fossiliferous parts by themselves and summing
up the result, we obtain from 1,000 to 1,200 feet thickness. In Albany
and Schoharie counties the thickness appears to be much greater than
in the western counties " (Agri. of N. Y., p. 185).

E. — Vanuxem wrote : " Near Marcellus and in other parts of Onondaga
where best observed they show no fossils for one or two hundred or more
feet where thickest" (Geol. N. Y., pt. iii, p. 147); also, "A boring of 100
feet for coal was made in the Marcellus shales by Mr Sage near the road
from Chittenango to Cazenovia" [Madison county] (ibid., p. 149); and
Dana states that " The Marcellus shale rarely exceeds in thickness 50
feet" (Manual Geol., 3d. ed., p. 267). Emmons stated: " It is probably
less than 100 feet at Schoharie and Manlius " (Agri. of N. Y., p. 183).

F. — Vanuxem said: "The Corniferous limestone is at its maximum
thickness in the village of Cherry Valley [Otsego county], where it is
probably from 60 to 80 feet thick" (Geol. N. Y., pt. iii, p. 141) ; while

112 C. S. PROSSER — DEVONIAN AND SILURIAN ROCKS.

he stated that the thickness of the Onondaga limestone " rarely exceeds
10 or 14 feet " (ibid., p. 132), and at Vannep's, near Perryville, Madison
county, ho gave the thickness as " about 10 feet" (ibid.., p. 135). Dana
wrote : " In New York the thickness of the limestone seldom exceeds 20
feet for the Onondaga and 50 feet for the Corniferous " (Manual Geol.,
p. 250'. Emmons reported 100 feet of Onondaga and Corniferous lime-
stone at Cherry Valley, in Otsego county (Agri. X. Y., table on p. 178;
also see statement on p. 175). From the above statements it appears to
be a fair estimate to call the ( !orniferous limestone of our section 60 feet
thick and the Onondaga limestone 10 feet.

G. — Yanuxem said : "'At Oriskany Falls [southwestern corner of Oneida
county], to the north of the village the sandstone is exposed for some
distance, forming a ledge or mass about 20 feet thick " (Geol. X. Y.. pt. iii.
p. 125) ; while " the greatest thickness in the district is on the old Seneca
road between Elbridge and Skaneateles [in the western part of Onondaga
county], appearing to be about 30 feet thick" (ibid., p. 283, and see
p. 126). Emmons reported: "At Oriskany Falls, 20 feet; at Perryville
and below Cazenovia, only a few inches " (Agri. X. Y., p. 170).

H. — Professor S. G. Williams stated: " The exposure of lower Helder-
herg rocks at Oriskany Falls, 18 miles south of Utica, is interesting, partly
because it is so laid open by deep and extensive quarries as to give nearly
a complete section of about 120 feet of rocks, 115 feet of which can be
definitely measured from the Oriskany sandstone, here 10 feet thick,
down to the bank of the abandoned Chenango canal " (Am. Jour. Sci.,
3d ser., vol. xxxi, p. 142). Emmons reported 121 2 feet at Cherry Valley,
Otsego county (Agri. X. Y., table on p. 178).

I. — Yanuxem. in 1840, reported " a thickness in Onondaga county of
about 7<H) feet" (4th Ann. Rep. Third Geol. Dist. X. Y., p. 375); while
in his final report he stated that the "thickness gradually increases
toward the west [from the Hudson river], and reaches its maximum in
the counties of Onondaga and Cayuga, where it is not less than 700 feet "
(Geol. X. Y., pt. iii, p. 96) ; also, the red shale of this group is said to
have <>reat thickness in Onondaga county, " being more than 500 feet
thick at Salina, which the deep boring of 1839 made known" (Yanuxem.
5th Ann. Pep. Third Geol. Dist. X. Y.. 1841. p. 147). This was also re-
stated in the final report (see Geol. X. Y.. pt. iii. pp. 278, 279). Professor
Hall reported that on a line from Seneca or Ontario to Oswego county
it is "more than 1,000 feet in thickness" (27th Ann. Rep. X. Y. Stale
Mus. Nat. Hist,. 1875, p. 128, and Proc. Am. Assoc. Adv. Sci.. vol. xxii,
1874, B, p. 332); while Dana says: "They [the Onondaga Salt group
beds] are 700 to 1,000 feet thick in Onondaga and Cayuga counties and
only a few feet on the Hudson " (Manual Geol., p. 233). Emmons re-

REVIEW OF AUTHORITIES. 113

ported 700 feet of red shale in Madison county and 100 feet of green
shale at Cherry Valley (A-gri. N. Y., table on p. 178).

J. — Vanuxem stated : " It [the Niagara] thins out to the east, leaving
not a trace to be seen east of a line passing south through the village of
Mohawk, in Herkimer county" (Geol. X. Y.. pt. hi, p. 90); while Pro-
fessor Hall wrote : " Starting from the typical localit}^ of the Niagara
group, where, of the shale and limestone, we have a thickness of some-
thing more than 200 feet, and tracing the outcrop in an easterly direc-
tion, we find a very gradual but pretty constant thinning ofthebeds of the
formation, so that at a point 100 miles east of the Niagara river it has a
thickness of scarcely 100 feet. Farther eastward, in Oneida county, the
formation is still thinner " (27th Ann. Rep. N. Y. State Mus. Nat. Hist., 187").
p. 123 ; also Proe. Am. Assoc. Adv. Sci., 1874, vol. xxii, B, p. 327). Vanux-
em, in 1840, stated that " the greatest thickness of this group [the Protean,
divided later into Niagara and Clinton] must be over 200 feet" (4th Ann.
Rep. Third Geol. Dist. N. Y., p. 375). Emmons stated : " On Swift creek,
in Oneida county, it is a dark concretionary mass, about four or five
feet thick, accompanied with a dark-colored slate" (Agri. N. Y., p. 151").

K. — Vanuxem was able to measure part of this group on Swift creek,
a tributary of Sauquoit creek, in the southwestern part of Oneida county,
where beds to the thickness of 94 feet are exp< >sed, but he states distinctly
that this is not the entire thickness of the group (Geol. N. Y., pt. iii.
pp. 84, 85) ; while Dana states : " In Oneida. Herkimer and Montgomery
counties the rock is 100 to 200 feet thick. . . . Near Canajoharie,
which is not far from its eastern limit, the formation has a thickness of
50 feet " (Manual Geol., p. 220). Emmons stated : " It is 1 »etween 5t > and
60 feet in Warren, in Herkimer county " (Agri. N. Y., p. 150).

L.— The Medina in the State well, near Syracuse, has a thickness of
about 807 feet (see Englehardt, Ann. Rept. Supt. Onondaga Salt Springs
for 1884, pp. 1(3, 17) ; Avhile Professor Hall wrote : u This rock [Medina]
thins out entirely in an easterly direction in Oneida county, showing
from that point westerly as far as Lake Ontario a gradual increase in
thickness " (Geol. N. Y., pt, iv, 1843, p. 43). Since the line of the present
section is about half way between Syracuse and the eastern side of
Oneida county, it would seem from the above statements that 400 feet
would be about the thickness of the Medina for this section.

M. — On the northern branch of Salmon river, which is very nearly in
line with the present section, Vanuxem stated : " Not less than about 100
feet of the rock [Oswego sandstone] is there exhibited" (Geol. N. Y..
pt. iii, p. 70). Emmons stated: " The whole thickness of the sandstone
and limestone is not over 100 feet " (Geol. N. Y., pt. ii, p. 126). Professor
Emmons also reported the Oneida conglomerate at Utica as "a mass 20
or 30 feet thick overlying and resting immediately upon the thin-bedded

114 C. S. PROSSER — DEVONIAN AND SILURIAN ROCKS.

Lorraine shales " (Agri. N. Y., pp. 125, 120). Vanuxem reported the
Oneida conglomerate in Herkimer to he "from 15 to 25 feet thick ; "
while in a gulley southeast of Utica "it appears to present its maximum
thickness of ahout 35 feet" (Geol. N. Y., pt. iii, p. 76). Dana stated the
thickness of the Oneida conglomerate to be " 100 to 120 feet in Oneida
county, New York " (Manual Geol., p. 218), and, further, "the Oneida
conglomerate is the surface rock in Oneida and Oswego counties, New-
York. It is here 20 to 120 feet thick, but thins out to the eastward in
Herkimer county " (ibid., p. 220). He evidently used the terms Oneida
conglomerate and Oswego sandstone as synonymous, and gave the thick-
ness of the Oswego sandstone for that of the Oneida conglomerate.

N. — Above the Utica shale, on the south branch of Sandy creek, Jef-
ferson county, New York, a locality not far west of the line of this section,
Mr YValcott measured 600 feet of shales and sandstones belonging to the
Lorraine stage iBull. Geol. Soc. Am., vol. 1, April, 1890, pp. 348, 349).
On the " diagram " for the Lorraine section Mr Walcott gave 180 feet as
Utica, then 100 feet of shale and calcareous sandstone, with 720 feet of
the Lorraine above (ibid., p. 350). Furthermore, Mr Walcott has stated :
"The data obtained in the study of the strata of the Hudson terrane
enables me to state that that terrane has a thickness of over 6,000 feet in
the valley of the Hudson" (Ninth Ann. Rep. U. S. Geol. Surv., pp. 116,
117). Vanuxem wrote: "In Schoharie county the Hudson group is
undisturbed and unaltered, and its maximum thickness is not less than
700 feet" (Geol. N. Y., pt. iii, p. 61). Mather concluded: " In the val-
leys of Norman's kill, the Mohawk river and the Schoharie kill, they
[Hudson] are beautifully exposed to view. . . . No actual meas-
urements of these strata have been made, but it is estimated that they
have a thickness of from 500 to 800 feet " (Geol. N. Y., pt. i, 1843, p. 369).
Ashburner described the Knowersville well, in Guilderland township,
Albany county, seventeen miles from Albany, which began 595 feet below
the top of the Hudson and reached the Trenton at a depth of 2,880 feet.
Consequently the Hudson group and Utica shale, if the latter be repre-
sented in this well, have a combined thickness of 3,475 feet (Trans. Am.
Inst. Min. Eng., vol. xvi, pp. 951, 952). Professor Hall gave it as from
800 to 1,000 feet thick in central and northwestern New York (Gd >1 . Surv.
N. Y., Paleontology, vol. iii, pt. i, text, p. 20, foot note). Professor Em-
mons reported the entire thickness of the Lorraine shales at the northern
termination of the Helderberg range as "not less than 700 feet" (Agri.
N. Y., p. 125).

O. — Mr Walcott measured ISO feet of "dark bituminous shale in bands,
alternating with a smoother lead-colored shale," along the south branch
of Sandy creek, Jefferson county, New York, which was "characterized
by the fauna of the Utica shale*' (Bull. Geol. Soc. Am., vol. i. p. 318).

REVIEW OF AUTHORITIES. 115

Emmons stated : " The Utica slate, in the gorges of Lorraine and Rod-
man [in the southern part of Jefferson county], is about 75 feet thick; it
is, at least, less than 100 feet" (Geol. N. Y., pt. ii, p. 118) ; and also he
said : " I am satisfied that its thickness never exceeds 75 feet " (ibid., p.
400). Vanuxem considered its thickness and reported it as " often show-
ing a thickness whose maximum is about 250 feet" (Geol. N. Y., pt. iii,
p. ^>G). Dana said : " The Utica shale is 15 to 35 feet thick at Glenn's
Falls, in New York, 250 feet in Montgomery county, 300 feet in Lewis
county " (Manual Geol., p. 196). Finally, Mr Walcott stated : "At the
typical locality in the vicinity of Utica the formation has a thickness of
over 600 feet" (Trans. Albany Inst., vol. x. 187'.), p. 1). This statement
was repeated in 1888 when the Campbell well was described, in the record
of which 710 feet was referred to the Utica shale (Proc. Am. Assoc. Adv.
Sci., vol. xxxvi, p. 212). Walcott stated in 1890 that " at Utica the Utica
shale is 710 feet in thickness " (Bull. Geol. Soc. Am., vol. i, p. 347).

P. — Mr Walcott reported that in the Campbell well, west of Utica, there
was probably 330 feet of Trenton limestone, and in the vicinity surface
outcrops 290 feet in thickness (Proc. Am. Assoc. Adv. Sci., vol. xxxvi.
p. 212). Vanuxem stated that the Trenton limestone at Copenhagen,
Lewis county, "must be 300 feet thick, showing a great increase in its
progress from the Mohawk river, where in no place is it 30 feet in thick-
ness " (Fourth Ann. Rept. Third Geol. List. N. Y., pp. 364, 365); also,
'• on the Mohawk its thickness rarely exceeds 30 feet, but it increases
through Oneida and Lewis, being 300 feet in the north part of the
latter county" (ibid., p. 371). In his final report this statement is
repeated as follows : " The greatest thickness of the Trenton limestone is
in Lewis county, toward the northern end, where it cannot be less than
300 feet. It diminishes in thickness going east and south, rarely exceed-
ing 30 feet in any part of the Mohawk valley. It is not so thick at the
east as at the west end " (Geol. N. Y., pt. iii, p. 49 ; also, see similar
statement on p. 268). Emmons said : " The greatest thickness which I
have been able to give to the Trenton limestone is 400 feet. At Chazy,
where it is made up of alternating beds of limestone and shale, this,
according to the best estimate I can make, is the thickness of this rock.
The gray variety is, however, wholly wanting at this locality ; if that is
to be considered as a distinct mass, the whole thickness may be greater
than I have given it ; but at Watertown, where both varieties exist, the
thickness cannot much exceed the above estimate. At Glen's Falls it is
much less "(Geol. N. Y., pt. ii, p. 116); also, "the thickness of the
Trenton limestone at Watertown, including the whole mass, which
extends south, and which is embraced in the section, is about 300
feet" (ibid., p. 388). The Black River limestone " is about 10 feet thick

XVII— Bull. Gkol. Soc. Am., Vol 4, WX2.

116

C. S. PROSSER DEVONIAN AND SILURIAN ROCKS.

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118 C. S. PROSSER DEVONIAN AND SILURIAN ROCKS.

at Fort Plain " (Vanuxem : Geol. N. Y., pt. iii, p. 40). The Birdseye
limestone " is about 30 feet [thick], but, like other limestones in this
group, it thins out remarkably toward the south " (Emmons : Geol. N.
Y., pt. ii. p. 110; also, see p. 385).

Q. — Mr Walcott reported surface outcrops of Calciferous 350 feet in
thickness for comparison with the Campbell well west of Utica, in which
it possibly lias a thickness of 360 feet (Proc. Am. Assoc. Adv. Sci., vol.
xxxvi, p. 212). Emmons wrote : " The entire thickness of the Calciferous
sandrock is between 250 and 300 feet " (Geol. N. Y., pt. ii, p. 106).

R. — Mr Walcott reported Potsdam (?) sandstone 410 feet in thickness
in the Campbell well west of Utica (Proc. Am. Assoc. Adv. Sci., vol.
xxxvi, p. 212). Emmons stated that on the northern or Canadian slope
it " is about 300 feet thick " (Geol. N. Y., pt. ii, p. 103). Mr T. B. Brooks
reported in St. Lawrence county Potsdam and pre-Potsdam at the maxi-
mum 700 feet thick, part of which must be before the typical Potsdam
(Am. Jour. Sci., 3d ser., vol. iv, p. 22).

Vanuxem in 1839 stated that the thickness of the whole series, from
the gneiss at Little Falls to the top of the Corniferous, " taking the
measure of each rock and group where its thickness is greatest, exceeds
2,000 feet" (Third Ann. Rept. Third Geol. Dist, N. Y., pp. 276). The
estimated thickness of this same series as compiled from various author-
ities is 3,530 feet, while the actual- thickness as obtained from the well
sections is 4.760 feet. In addition, Vanuxem stated : " There [then] re-
mains from 12 to 1,500 feet before completing the whole of the series of
the third district; all which are anterior in origin to the coal " (ibid., p.
276). This would make a total thickness of only 3,500 feet for the entire
series, while our compiled section gives 6,775 feet from the top of the
Chemung to the Archean, and the actual thickness of the rocks from the
Chemung, at Binghamton, which is something like 1,500 feet below the
top of Vanuxem's series* to the Archean is approximately 8,895 feet.

Comparative Sections of eastern, central and western New York.

For the purpose of comparison it has been thought advisable to prepare
a chart (page 116) giving the thickness of the different geological for-
mations for four sections, crossing New York in a line from north to south.

The author is responsible for the sections denominated *' western,"
"western-central" and "central New York," but the section for "eastern
New York " was measured and prepared by Charles A. Ashburner.

*Compare the Chenango section (ix) in Professor Williams' "Meridional Sections of the Upper
Devonian Deposits of New York, Pennsylvania and Ohio" (Proc. Am. Assoc. Adv. Sci., vol. xxxiv).

Topeka, Kansas, December, 1892.

BULL. GEOL SOC. AM

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BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA
Vol. 4, pp. 119-132, pl. 1 February 23, 1893

A NEW TSENIOPTEROID FERN AND ITS ALLIES

BY DAVID WHITE

(Read before the Society August 16, 1892)
( !ONTENTS

Paste

Introduction 119

Diagnosis 119

Locality 120

Specific Resemblances. 120

Generic Reference 121

Suggested genetic Relations 123

Systematic Position and Relation of the megalopterid Group 125

Graphic Presentation of Relations 129

Conclusions 129

Introduction. — Among several collections of fossil plants from the Lower
( !oal Measures of the Carboniferous of Henry county, Missouri, have been
found a number of specimens representing a remarkable and apparently
new species which presents a striking combination of tseniopteroid and
alethopteroid characters. Tins species is of peculiar interest from the
fact that it exhibits divisions of a type well known in certain Paleozoic
and Mesozoic tseniopteroid forms arranged and developed in the manner
familiar in the genus Alethopteris, as will be seen in the accompanying
figures and following description :

Tseniopteris missouriensis, n. sp.

Pl. I, figures 1-7.

Diagnosis. — Fronds bipinnate(tripinnate?),the larger divisions linear-
lanceolate, acute, composed of pinnatifid pinnules near the base, above
which are simple pinnules; primary rachis broad, shining, marked by
somewhat irregular lines, and consisting of a thickened central portion,
broadly but shallowly canaliculate above, half-round below, and of
thinner marginal laminae ; pinnules opposite, sub-opposite or alternate,

XVIII— Buo,. Gkol. Soc. Am., Vol. 1, 1892. (U")

120 D. WHITE — A NEW T.ENTOPTEKOID FERN AND ITS ALLIES.

slightly distant, at right angles or reflexed below, becoming more oblique
above, ribbon-like, gradually tapering from the lower part, with borders
straight or slightly undulate and nearly parallel, to a rather acute ti]>,
long, sometimes reaching a length of 8 cm or more, and measuring 6 to
13 mm in width, the lower ones slightly narrowed toward the cordate,
nearly symmetrical base with its narrowed attachment which overlaps
the marginal lamina of the rachis, the higher ones becoming attached by
the whole base, those near the top of the pinnae becoming shorter, more
distinctly decurrent and confluent, the margins more rapidly converging ;
limb of the pinnules rather thick, dull, broadly canaliculate along the
midrib, somewhat convex near the borders, overlapping the marginal
lamina? of the rachis. constricted to a rather narrow attachment in the
lower and middle pinnules, spreading and uniting those near the apex
of the pinna? where it forms a wing incised by acute and decurring angles
at the confluence of the pinnules ; nervation tamiopteroicl, midrib strong,
depressed, broad and striate beneath, broadly canaliculate above, origi-
nating from the central portion of the rachis, passing along the middle of
the lamina and tapering to the apex of the pinnule ; lateral nerves rather
fine salient above, distinct beneath, originating at an oblique or some-
times nearly a right angle from a slender cord-like bundle often distinctly
in relief traversing the center of the canal, usually forking at or near the
midrib, rarely simple, curving quickly if oblique, and passing fairly
straight and generally parallel perpendicularly to the border, usually
forking again at a varying distance in the lamina, and counting 24 to 28
per cm at the margin ; basal nervils of the upper decurrent pinnules
springing from the rachis ; those of the uppermost alethopteroid pin-
nules becoming rather more oblique in passing to the margin.

Locality. — Represented by ten specimens from Hobbs1 bank, nine miles
south of Clinton, Missouri, and one specimen from Deepwater, about
eight miles southeast of Clinton.

Specific Resemblances. — Among the known Paleozoic plants are several
species described as Damseites, Alethopteris, Taeniopteris and Desmopteris
which have many characters in common with Tivnioptcris misxoiiricnsis.
Of the American forms, Danssites {Alethopteris) macrophylla, Newb. sp.,
Alethopteris maxima, Andr., the types ranged under Orthogoniopteris and
Protoblechnum, and an unpublished species of Callipteridium described by
Lesquereux deserve comparison. Newberry's Alethopteris macrophylla,1
the fully developed pinnules of which are somewhat similar to tbose of
our specimens, is alethopteroid in arrangement, only the lowest, so far as
I have observed, becoming contracted to the obliquely cordate base.
Besides its more delicate habit, it further differs by the obliquity of the

1. Geol. suvv. Ohio, Pal. I. i>. 383, pi. xlviii, figs. ::, :■„,.

SPECIFIC RESEMBLANCES. 121

narrowed bases of the distinct pinnules, the more slender upper, con-
fluent pinnules and the closer nervation. There is perhaps no generic
difference between the two plants. Alethopteris maxima, Andr.,1 as seen
in a specimen from Rushville, Ohio, determined by Professor Lesquereux,
is an alethopterid, though the difference between it and Protoblechninu
may not be of generic rank. Still earlier in the geologic series a form
perhaps somewhat similar existed in the Alethopteris ingens, Daws.,2 the
pinnules of which, more than one inch in width and three inches or more
in length, have the Bauxites nervation, or the J. discrepans, Daws.,3 both
from the middle Devonian of St. Johns, New Brunswick, the long, ribbon-
like, open pinnules of which are united, however, by a narrow decurrent
wing. So far as the form and development of the pinnules, and to some
extent the nervation, is concerned, a closer resemblance obtains in the
cases o£ Pseudodanxupxix reticulata, Font.,4 from the Upper Trias at Clover
Hill, Virginia, or the forms of Tseniopteris munsteri, Goepp. (Angiopteris,
fide Schenk), from the Lias of Bornholm.5 Tin; upper pinnules of the
Virginia species are united, as figured by Fontaine, while the lower ones
are long, ribbon-like, and distinctly and nearly equally rounded at the
base, as in our plant from Missouri. Perhaps its nearest affinity is, how-
ever, with the Tie nioptcr is jejunata of Grand Fury,''' from the Upper Car-
boniferous and Permian of France. In this species, of which the upper
parts of the pinnae are, I believe, unknown, the pinnules are sometimes
short-pedicelled, the lamina thin, and the nerves generally more oblique
near the midrib and more regular, as figured, in passing to the margin
than in our species.7 Inform the Missouri species is also close to certain
species referred by Stur8 and Zeiller9 to Desmopteris, Stur, which has a
somewhat different nervation, though it appears to be allied to the
alethopteroid gr< >up.

Generic Reference. — In the characters of the rachis with its thickened,
sulcate, center and marginal laminae, in the origin of the nervils in the
median canal of the pinnule, the ribbon-like lamina of which is rounded
at the base where it overlaps the rachis, and, to a less extent, in the
character of the nervation, the middle pinnules (figure 5) of our species
are referable to Tseniopteris or to Danseites, according to one's interpreta-

1. Geol. Surv. Ohio, Pal. II, p. 421, pi. I, figs. ::, Za-b.

2. Foss. PL, Dev. Sil. Form., Can., pi. xviii, tig. 206, i>. 54.

3. Op. cit., p. 54, figs. 203-205.

4. Older Mcs. Fl., U. S. Geol. Surv. Monogr., vi, p. 59, pi. xxx, figs. 1-4.

5. Bartholin: Botanisk Tidsskr., vol. xviii, lift, i, Kjobenhavn, L892, p. ■£',, pi. ix, fig. 9.

0. Fl. Carb. Loire, p. 121 ; Zeiller, Fl. 1'oss. Commentry, pt. 1, p. 280; All., pi. xxii. figs. 7-!); Zeiller,
Fl. foss. Autun, Epinac, p. 102, pi. xii, fig. 6.

7. The nervation seen in the figures of T. missouriemis is drawn with fidelity in detail from the
originals.

8. Carbon. -Fl. Schatzlarer Sch., i. See D. belgiea, Stur. p, isi, pi. Hi, rigs. 7-9.

9. Fl. foss. Valenciennes, p. 21G, pi. xxxviii, figs. 3-5. See Ettingshausen: fl. Radnitz, p. 1", pi
xvi, figs. 2-4.

122 D. WHITE — A NEW TTENIOPTEROID PEEN A.ND ITS ALLIES.

tion or restriction of those genera, while it has much also in common
with certain Triassic and Jurassic forms referred by various authors to
Angiopteridium, Angiopter'is, Marattia and Danseopsis. One or two of the
lowest pinnules found arc sublobate or crenulate on the lower side, as
though in the procsss of subdivision, such as I take to be the case in the
Danseites (Alethopteris") macrophylla figured by Newberry.1 On the other
hand, the upper, sessile, confluent or decurrent pinnules (figure 2),
though springing from the central portion of the rachis (a condition indi-
cated in some species of Alethopteris), are equally distinctly alethopteroid,
being comparable to those pinnules seen in the upper part of primary
pinna; of various Alethopteridese, such as Alethopteris valida, Boul.,2 or in
the A. gigantea and A. longifolia of Achepohl,3 both of which may be
allied with the group of long-pinnuled Paleozoic Danseites. It is prob-
ably generically inseparable from the Danseites (Alethopteris) macrophylla,
Newb. sp.

But under the name Danseites we have two quite different groups of
plants. The genus Danmtes, as construed by Ettingshausen, Heer and
Schimper,4 embracing those forms in which the pinnules, having the
characters of Tssniopteris, are rounded at the base and attached by the
midrib only, differs widely from the interpretation put upon Goeppert's
ambiguous genus by Stur5 and Zeiller,6 who, on account of the obscure
fruiting figured by Goeppert,7 have denned it to contain a number of
pecopteroid forms with small pinnules and sori which, though not under-
stood in certain respects, are strongly analogous to those of the living
Dansea. The Dunn ilex ernersoni of Lesquereux,8 referred to Goeppert's
genus by reason of the appearance of its obscure fruiting,9 represents,
according to the figures, an alethopterid form related by habit and
venation to Gallipteridium, while the D. macrophylla, Newb*. sp., was not
placed by Lesquereux in Ta niopteris, to which it was considered referable
in size and nervation, because it was pinnate, the unequally cordate base
excluding it at the same time from Alethopteris. However, cordate or

1. Oeol. Surv. Ohio, Pal. I, p. 383, pi. xlviii, tigs. :i, 3a.

2. See Zeiller, Fl. foss. Valenciennes, p. 231, pi. xxxii, xxxiii, tig. l.

3. Niederrh.-Westphal. St. 'ink., p. 78, pi. xxiv, tig. 12 3 p. 134, pi. xli, figs. 1, 1'.

I. [n Zittel, Traite, iiyp. 85: "Feuille simple (ou double?), pen nee. Folioles inserees seulemeul
par la. nervure mediane, arroDdies :i la base, lineaires, devenant insensiblement pointues, poss6-
ilant les caraeteres des 'J'" niopteris, ;i bord entier : nervure moyenne ;is»7, forte, nervures lateral.es
se detaehant de alles-ci a angle droit, nombreuses, les unes simples, les autres bifurquees. Fructi-
fications disposers en deux series le long de la nervure m6diane."

5. Carbon.-Fl. Schatzlarer Sch., p. 221, figs. -Y\a-c.

0. Fl. foss. Valenciennes, p. 41.

7. Systema, p. 380; Danceites asplenioides, p. 380, pi. xix, figs. -1, •">.

8. Coal Flora, p. L57, pi. xxviii, tigs. l-:s.

9. The Pecopteris asplenioides described by Fontaine anil 1. C. While (Permian Flora, p. 72, pi.
xxv, fig. I), from the Permo-Carboniferous, is perhaps closely related generieally, by its fruiting, to
D. ernersoni, Lesq.

GENERIC REFERENCE. 123

neuropteroid bases are not very rare in-the lowest pinnules of Alethopteris
and Callipteridium. In recent works interpreting the fossil according to
the habit of recent ferns, a simple frond is not generally made an essen-
tial character of the genus Tmniopteris. So far, I believe, no one has de-
scribed the upper portion of the pinna of any of the pinnately divided
speeies now retained in the latter genus, the remains consisting generally
< f detached pinnules and fragments separated by reason of their decidu-
ous tendency.

My reference of the Missouri species to Ta niopteris is provisional. The
fern is in its habit, and to some extent its nervation, evidently closely
related to Alethopteris. As remarked above, it should perhaps be in-
cluded in the same genus with Danasites (Aleth.) macrophylla (Newb.)
Lesq. ; but from the character of the rachis, midrib, form of pinnules
and the nervation, and from the observed development of the upper part
of some of the tseniopteroid forms in the older Mesozoic and Carbonif-
erous, I have been led to place it among the Taeniopterideae, and notwith-
standing the high degree of its superficial identity with them arattiaceous
forms comparable in their fructification to Danasa or Angiopteris, it seems
better, in default of all knowledge of the fruiting of our species, to refer
it to the genus Tmniopteris, the former resting-place of many of the Meso-
zoic species, rather than to the equivocal genus Dana ilex. It is certainly
ineligible to admission in the Dana ites of Goeppert and Stur. The name
Danasites, in the sense in which it is employed by Heer and Schimper,
should, if used at all, perhaps be applied to those species only of which
either the fruiting is known or the generic identity with other contem-
poraneous fruiting species is by other evidence satisfactorily proven,
leaving their apparent representatives from the Paleozoic, the fruiting of
which is not known, in the convenient and non-committal genus Taeniop-
teris, without presupposing any direct genetic relation to any particular
fruiting genus.

Suggested genetic Relations. — The combination of alethopteroid and
tseniopteroid characters in the plant from the Lower Coal Measures of
Missouri more than strongly suggests a genetic relationship between the
pinnate tseniopterids (including the Paleozoic Danseites of the type A
macrophylla), and in probable sequence the Mesozoic tseniopteroid marat-
tiaceas, on the one hand, and the Lower Carboniferous alethopteroid
genera on the other; or, considering together with the alethopterids their
close natural allies, the neuropterids, we may suppose the relationship
to extend, as I shall try briefly to indicate, back to the megalopterid
stock, in which they may have had their origin.

The genus Megalopteris, described from the Middle Devonian of Saint
Johns, New Brunswick, by Sir William Dawson as a subgenus of

124 I). WHITE — A NEW TjENIOPTEROID FERN AND ITS ALLIES.

Neuropteris,1 becomes, in the Lower Carboniferous, alethopterokl in its
mode of development and configuration, while its nervation is that of
Alethopteris or Odontopteris. The pinnules are further distinguished by
their thick midrib, which is canaliculate above, semi-cylindrical beneath,
nan-owing in passing up, but distinct to the apex of the lamina. Les-
quereux, who frequently pointed out its ancestry to, or at least its com-
mon descent with, the neuropterids, adds2 that " except for the characters
of the nervation [open, curving, close, dichotomous] this genus is not
separable from Danseopsis, I leer. Saporta and Marion :i include the genus
Megalopteris with Cannophyllites, Brgt., in the Cannophyllitess, which they
regard as being near the Dolerophylhas among their " Progymnosperms,"
a- view in which Count Solms-Laubach and Schenk do not concur.
Between the more alethopteroid forms of Megalopteris, such as M. hartii*
M. ovata,5 M. minima,6 M. abbreviata1 and the alethopteroid genera found
in the Lower Carboniferous of Ohio and West Virginia, the resemblance
is so close as at once to force a comparison.

Among the forms from below the Maxville limestone in Ohio, the
generic delimitations of which are perhaps more artificial than is com-
mon even among Paleozoic ferns, the Alethopteris maxima, And.,8 is found
to have a close tamiopteroid nervation in pinnules which are decurrent
and confluent in the upper part of the pinna, but scarcely confluent in
the lower part, where their mode of clecurrence, in a semi-auricle, is nearly
that given as a chief characteristic of Orthogoniopteris, regarded by An-
drews, its author, as comparable to Angiopteridium and Neriopteris, with
many of the characters of Dansea.9 Alethopteris holdeni of Andrews10 is
described by Lesquereux " as agreeing in most respects with Orthogoniop-
teris, but is removed by him to form a new genus, Protoblechnwm, its nerves
being rather more curved than in Orthogoniopteris, while it is excluded
from Alethopteris by its supposed simply pinnate fronds. It would, per-
haps, be not incorrect to designate these " Waverly " forms, occurring in
the same deposit with the above-mentioned species of Megalopteris, as
Alethopteroid megalopterids. Neriopteris, from the conglomerate series of
northern Ohio, with its sessile or short-petioled pinnules and oblique
nervation, in fineness and regularity rivaling that of Macrotaeniopteris, has.

1. Foss. PI. Dev. Upp. Sil. Can., p. 51, p!. xvii, tigs. 191-194.

2. Coal Flora, I, p. 148. See Ann. Rep't Geol. Surv. Pa., L886, pt. 1, p. 47."..

3. Evol. re,g. veg., Phanerog., p. 77.

4. Andrew s, < Jeol. Surv. < >hio.. Pal. II, p. 416, pi. xlvi, figs. 1, la.

5. Ibid., p. 417, pi. xlvii. figs. 1, '-', 2a.

6. Ibid., p. 4lii, pi. xlviii, figs. l-:s.

7. Lesquereux, Coal Flora, p. 151, pi. xxiv, fig. :;.

8. [bid., p. 421, pi. 1, figs. 3. ■;n-h.

9. [bid., |>. tl.s. pi. 1, figs. 1, la.

10. Ibid., p. 420, 1)1. li, figs. 1. 2, 2a,

11. Coal Flora, v.,i. I. p. L88,

SUGGESTED GENETIC RELATIONS. 125

i

according to Newberry, an equal degree of affinity to Alethopteris and •
Teeniopteris, and is separated from Teeniopteris only on account of its once
or twice pinnate frond and the oblique nerves. It is interesting to note,
in connection with this circumstance, the case of the Alethopteris macro-
phylla described from the same horizon by Newberry, who says that but
for the rectangular nervation lie should be inclined to include it in
Neriopteris, while Lesquereux, on the other hand, refrained from referring
it to Teeniopteris- only because it was pinnate, placing it in Daneeites in-
stead. The backward rolling of the margin of Neriopteris may be only a
more pronounced phase of what is common in species of Alethopteris, or
it may be an indication of fructification. Newberry's description and
figure of Neriopteris lanceolata 1 may with advantage be compared with
those given by Lesquereux2 under the name Megalopterisf marginaia.

Systematic Position and Relations of the megalopterid G roup. — A critical
comparative study of the alethopteroid megalopterids will hardly fail to
lead to the conclusion that in the early part of, perhaps before, the Sub-
carboniferous, the Megalopteris stock attained a high differentiation, in
which the Alethopteroid group produced in Neriopteris, Orthogoniopteris,
Alethopteris, Protohlechnum and Danseites (Heer-Schimp.) certain forms
embracing the essential characters of the pinnate Tseniopteridese. From
this Lower Carboniferous group, doubtless including many undiscovered
variations, may well have descended such forms as the Teeniopteris mis-
souriensis in the Lower Coal Measures of the American continent, the T.
jejunata, Grand Eury, and T. carnoti, Zeill., of the Upper Coal Measures of
France, or the perhaps somewhat doubtful megalopteroid, T. truncata,
Lesq.,3 from the Conglomerate series.

As interpreted by superficial characters, the sequence of the Paleozoic
tseniopteroid types into the Triassic forms, many of which have at some
time rested in the genus Teeniopteris until the fruiting, either of them-
selves or of contemporaneous obviously generically identical species, has
been discovered, proving them to be true ancestors of living genera in
the Marattiaceee, affords strong evidence at once both of the great an-
tiquity of the group and its lineal descent from the Megalopteris stock.

The figures of Goeppert's Teeniopteris munsteri, from the Rhetic of
Bavaria, given by Schimper* on referring the species to the genus Ma-
rattia, though apparently diagramatic in part, and those published by
Bartholin5 deserve a comparison with Neriopteris and Dana ilex of the
type macrophylla, Newb. sp., and the species becomes more interesting

1. Geol. Sunr. Ohio, Pal. I, p. 381, pi. xlv, figs. 1-3, 3a.

2. Coal Flora, I, p. 152, pi. xxiv, tig. 4.

3. Coal Flora, III, p. 743, pi. xciv, fig. 8.

4. In Zittel : Traite, II, p. 85, fig. R4; Traits pal. vfig., Atlas, pi. xxxviii, fig. I.

5. Botanisk TMsskr., vol. xviii, hft. 1, 1802, p. ■£',. pi. ix, tigs. G, 9.

120 I). WHITE — A NEW T-SJNIOPTEROID FERN AND ITS ALLIES.

in view of the discovery in the Conglomerate series of Ohio of a form
thoroughly Mesozoic in aspect that has been referred to the genus
Danseites (Heer-Schimp.) by Lesquereux. From the study of many
specimens of Tasniopteris munsteri, Goepp., fruiting from the Rhetic of
Bavaria, Schenk was led1 to refer the species without hesitation to the
genus Angiopteris, being unable to find any character warranting a ge-
neric separation. Raciborski, on the other hand, is convinced that the
fruiting of what he considers the same species in the Rhetic of Poland is
that of the true Marattia. A nother tasniopteroid species which merits con-
sideration is the Danasopsis marantacect ( Presl.) Hcer, from the Keuper, the
fruiting of which is distinctly marattiaceous, and which was regarded by
Schenk2 as very close to the living Dana a. The fine illustrations of this
species given by Schimper3 may with great interest be compared with
the Megalopteroid group from Ohio. The habit of Schimper's specimen,
representing the upper portion of a pinna, seems such as to suggest that
the lower pinnules may be distinct and not confluent, a suggestion em-
phasized by the figures given by Schoenlein4 and Saporta.5

As tending to confirm this view, I may add that in Pseudodanasopsis, a
genus of plants from the Upper Trias of Virginia, separated by Fontaine
from Danasopsis chiefly on account of its anastomosing nerves, the lower
and middle pinnules of the species P. reticulata, Font., represented by
numerous specimens in the United States National Museum (No. 3488),
are distinct, distant, equilaterally rounded at the base and in all re-
spects distinctly tseniopteroid, except for the frequent anastomosis of the
nervils, although the upper portions agree to a great extent with the
habit and characters of Danasopsis marantacea.

The establishment of the existence of the actual genera Angiopteris or
Marattia in the Rhetic attributes to them a remarkable antiquity, un-
equaled, so far as I know, among any other living fern genera; but indis-
putable specimens of Dansea, with their fructification, were described by
Zigno 6 from the Lias of Verona, proving for this genus a nearly equal
antiquity. It follows that the epoch of indefinite length marking the
genesis or lineal descent of these two marattiaceous genera must there-
fore have terminated by the close of the Triassic. However, since none
of the forms of the Danasopsis or tseniopteroid Danasites types have been
found with distinct fruiting earlier than the Keuper, the direct lineage
of the actual genera cannot be traced backward into the Paleozoic with
any greater definiteness than a high degree of probability or likelihood.

1. Die loss. Pflanzeur., p. 30, (i.e. HB.

2. ( »p. cit.. p. 35.

:;. Traits pal. v6g., Atlas, pi. xxxvii, figs. l-:t.

I. A.bbild., pi. vii, lig. 2.

5. V6g. Jurasa., I, pi. Ixv, p. 154.

(i. PI foss. oolit., \<<\. I, pi. xxv. pp. -.'os, 209.

POSITION AND RELATION OF MEOxALOPTEROID GROUP. 127

In the absence of fruiting it may therefore justly seem inexpedient to
many to refer pre-Keuper tseniopteroid species to genera like Angiop-
teridium or Danseopsis, founded on or implying a known direct relation-
ship to a certain marattiaceous genus. It is for this reason that, as stated
above, I have preferred the use of Tssniopteris as a generic name devoid
of all implication of an antecedent relation of a species to any particular
genus.

The probable relationship of the Carboniferous Tssniopteris to the Meso-
zoic Marattiacess has been well expressed by Professor Zeiller,1 while that
of the Mesozdic types of the genus has been ably discussed by Zigno,'2
Saporta3 and others, nearly all of whom ally them directly with the liv-
ing genera. The occurrence of pinnate tseniopterids, such as Tssniopteris
jejunata, Grand Eury, and T. carnoti, Zeill., in the Carboniferous and Per-
mian of France; T. coriacea and T.fallax, Goepp., in the Permian of Bo-
hemia; T. eckardi, Germ., in the Permian of Tyrol, and the Danseopsis
Rajmahalehsis, Feist., in the Trias of India, the last two of which were
regarded by Schimper4 as agreeing entirely with the Keuper Danseopsis,
completes the continuity of the discovered pinnate tseniopteroid forms
from the Subcarboniferous types to the Keuper, and may be considered
as belonging to a not improbable genetic series passing from the alethop-
teroicl megalopterids of the Lower Carboniferous — perhaps from the
genus Megalopteris itself— to fruiting forms, in the late Trias, of the living
genera Angiopteris, Marattia and Dansea.

The relationship of the simple-leaved species of Tssniopteris to those
with pinnate fronds is somewhat uncertain, though it does not seem im-
probable that all came from the same stock, it is not impossible that
the species of the type T. multinervis, Weiss., or T. smithsii, Lesq., as well
as the genus Lesleya,5 may have come from the megalopterid type through
an early variation. M. Zeiller. who has discovered forms referred by him
to the latter genus in the Upper Carboniferous and Permian of France,"
associates it with Ta niopteris, and indeed the obliquity sometimes seen in
the nerves of Tssniopteris,'1 as well as the distinctly tseniopteroid aspect
of Lesleya, gives strong support to this view. The descent of the two

1. "Aucune des Teniopteridees du terrain houiller n'arencore ete rencontree 6 Petat fertile; raais
quelques-unes d'entre elles presentent d'assez etroites affinites avec eertaines Teniopteridees sec-
ondares reconnues anjourd'hui eomme tres voisines au morns des genres Angiopteris, Marattia, on
Dancea, pour qn'on soitfonde a croire qu'elles doivent, elles aussi, appartenir aux Marattiaees." Fl.
foss. bassin perm. Autun et Epinae, p. 160.

2. Fl. foss. oolit., vol. i.

3. Pal. franc., veg. Jurass., vol. i.

4. In Zittel: Traite, II, p. 86.

5. Lesquereux, Coal Flora, I, p. II::, Atlas, pi. xxv, figs. 1-::.

6. Fl. foss. bassin Autun Epinae, p. 166. See pi. xii, fig. 2; and Fl. foss. Commentry, pt. 1, p. 285,
pi. xxiii, fig- 6.

7. See T. multinervis, op. cit., pi. xiii, fig. 1.

XIX -Bull. Geol. Soc. Am, Vol 4. 1892

12S D. WHITE A NEW T.ENIOPTEROID FERN AND ITS ALLIES.

forms may reasonably be considered as common, if not lineal, the Les-
leya appearing to date back nearer, the type of Megalopteris dawsoni.1 On
the other hand, the conspicuously unequally rounded bases seen in some
species of Macrotseniopteris* suggest that the leaves may be only petioled
divisions, comparable in arrangement to the pinnules of Neriopteris lan-
ceolata, Newb., and be derived from pinnate forms. It may not be going
too far to add that from some Permian or Triassic species of T&niopteris
or Macrotseniopteris, essentially distinguished from the former only by the
greater size and sometimes thinner texture, may well have originated the
Oleandridium, thought by Schenk3 to be probably marattiaceous.

As tending to confirm the hypothesis of the descent of the genera
Angiopteris and Dansea from the Megalopteris stock may be noted the
probable relationship of the neuropterids, whose origin, as Neuropteris,
in or with Megalopteris is generally accepted by those who have studied
specimens of the latter genus, to the Marattiacese. Although no satisfac-
torily definite fruiting of any of the Neuropteridese has yet been discovered,
the internal structure of the stems described by Renault4 as Myelopteris
or Myeloxylon, and afterwards identified as Neuropteris, Odontoptosis and
Alethopteris, is found to resemble that of the living Marattiacese. more than
any other known type of fern structure. Thus, from the evidence afforded
by their internal structure, which has led M. Renault5 to include Alethop-
teris among the Neuropteridese,, the marattiaceous nature of Megalopteris
has already received strong support.

In this connection it is interesting to compare the illustrations of some
of the more alethopteroid species of Neuropteris, suchas N. retorquata,
Daws.,6 and N. selwynii, Daws.,7 from the Middle Devonian, N antecedens,
Stur,8 and N dluhoschi, Stur9 (cf. N elrodi, Lesq.) from the Lower Car-
boniferous, N biformis, Lesq.,10 N matheroni, Zeill.,11 and the figures given

1. It is quite possible that from the Leslei/a type may have been derived the Glossopte.ris group
appearing in the Middle Carboniferous and Permo-Carboniferous of Australia. Lesquereux's diag-
nosis differs, as he remarks, from Brongniart's description of the latter only by the nerves not
anastomosing. In this connection it is interesting to consult Newberry's Tceniopteris ijlossopte-
roides (Macomb Expedition, 1S76, p. 147, pi. vii, figs. 2, 2a) from the Trias of Sonora, New Mexico.
The supposed fruit dots represented in his figure 5 appear quite similar to the dots seen between
the nerves of Alethopteris maxima, Andr.

2. See M. magnifolia, (Rogers) Sehimp., Fontaine, Old. Mes. PI., Monogr. U. S. G. S., vi, p. 19, pi. ii,
tig. 1, i>l. iii, iv, v.

3. Palseontogr., xxxi, 1881, p. bis.

4. Cours hot. foss., iii, p. 163..

5. 6p. cit., p. 152.

6. Foss. PI. Dev., Upp. Sil. Can., p. 50, pi. xvii, fig. 200.

7. Ibid., fig. 198.

8. Culm-Flora, p. 53, pi. xv, figs. l-r>.

9. Op. cit., p. 289, pi. xxviii, fig. 9.

10. Coal Flora, p. 121, pi. xiii, fig. 7.

11. FI. foss. Commentry, pt. 1. pi. xxviii. fig. 7.

GRAPHIC PRESENTATION OP RELATIONS. 129

by Von Roehl under N. plicata1 (= N. rectinervis, Kidst.)2 from the Coal
Measures, and N. voltzii, Brgt.,3 and N. salicifolia, Fisch.,4 from the Per-
mian, with the phases often seen in the basal portions of some species of
Alethopteris, as, for example, .4. lonchitica, A. grandini, or Callipteridium
sullivantii.5

On the basis of their fruitings, which are either exannulate or with only
a rudimentary ring, as well as from the analogies of their structure, all
modern authors agree in considering a large number of Paleozoic species
with pecopteroid nervation as most nearly allied to the Marattiacese
among living ferns.6 This conclusion is natural, in view of the known
antiquity of certain living marattiaceous genera, as well as the probable
long existence of the eusporangiate ferns in Paleozoic time before the
leptosporangiate forms appeared.

Graphic Presentation of Relations. — The following diagram represents in
graphic form the general idea of development for a few genera; but it is
not to be understood that the relations of individual genera are sup-
posed to be in all cases as therein indicated, nor that the scheme is meant
to imply a presumed proof or even the existence of evidence sufficient
to form the basis of a proof. The lines should indicate in most cases a
common rather than a lineal descent. It must be remembered that such
a scheme is largely mere speculation. Many of the implied relations are
improbable as well as incompatible. Some suggestions embodied in the
chart constitute my only excuse for presenting it.

Conclusions. — In the foregoing discussion of what may be regarded as
a tentative hypothesis for the line of descent of several of the living-
genera of Marattiacese from the Megalopteris stock, I have not presumed
to attempt a proof or demonstration among a body of forms whose fruit-
ing is essentially unknown; I have rather sought to bring together some
of the evidence in favor of what I consider a good working theory. Ac-
cording to this hypothesis, we may suppose that the pinnate Tasniop-
teridese, or a portion of that group (without prejudice of any important

1. Foss. Fl. Steink., Westfalens, pi. xx, figs. 7, 8; pi. xiii, fig. 8.

2. Trans. Roy. Soc. Ediub., xxxv, 1888, p. 314, figs. '-'-4.

3. Hist., pi. lxvii.

4. Kutorga, Verb. Euss. Kais. Min. GeselL, St. Petersb., 1842, pi. i, fig. 2.

5. From the analogous characters of the nervation the genera Neuropteris, Odontopteris, Lesteya,
Dictyopteris, Neriopteris, Megalopteris, and Tcenioptens were included in the Neuropterid group by
Lesquereux in one of his last publications on the Carboniferous flow (Ann. Rep. Geol. Surv. Penna.,
1886,pt.l,p.475). Renault (Cours. bot. foss., 3me annee) makes the Neuropteridece include Neuropteris,
Odontopteris, Dictyopteris, Alethopteris, Lonehopteris, Callipteridium, and Callipteris. More recently
Grand Eury (Geol. Pal. bassin houill. Gard., p. 286. construes the, tribe so as to contain AulacopU ris
(Mydopteris), Alethopteris. Callipteridium. Neuropteris. Dictyopteris, Odontopteris, Tamiopleris, and a
new pecopteroid genus, Parapeeopteris, intermediate in form between the neuropteroid Pecopteris
species and those of Neuropteris, with fructification after the fashion of Damea.

6. See Renault, Cours. bot. foss., 3e annee; Stur. Carbon PL Schatzlav. Sch., ii; Zeiller, PL foss.
Autun Epinac; Kidston, Trans. Geol. Soc. Glasgow, vol. ix, p. 1.

130

D. WHITE A NEW T/ENIOPTEROID FERN AND ITS ALLIES.

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CONCLUSIONS. 131

systematic distinction between the pinnate and simple forms), came from
an early Megalopieris stock, probably through the alethopteroid forms.
The earliest flora, so far as I know, in which any of these occur, that of
the Middle Devonian at Saint Johns. New Brunswick,4 besides contain-
ing the Megalopteris daivsoni, has also representatives of Neuropteris, most of
which are alethopteroid, and of Alethopteris, including the A. grandis and
A. discrepans already referred to. It is not improbable that the three
of these genera originated in a common stock ; and since the Megalopteris
group offers a comprehensive type from which the Neuropteris and Ale-
thopteris, as wrell as the known Megalopteris species, might well have
descended, that name may conveniently be employed in the hypothesis
to designate the type existing previous to the Middle Devonian, from
which the ncuropteroid, alethopteroid and tseniopteroid groups, includ-
ing in the latter some species of living marattiaceous genera, descended.

1. See Dawson, Foss. PI. Dev., Upper Sil. Form. Can., Geol. Serv. Can., 1871.

Explanation of Plate 1.

Tseniopteris missowriensis, n. sp.

Figure 1. — Fragment from upper middle portion of pinna. Pinnules nearly dis-
tinct.

Figure 2. — Portion near tip of pinna. Pinnules confluent.

Figures 3 and 4. — Apex of pinna, showing true AklhopU m development.

Figure 5. — Fragment from middle of pinna, showing taeniopteroid pinnules, dis-
tinct, contracted at the base, attached to the central axis of the
rachis.

Figures 6 and 7. — Fragments of detached pinnules. The broad character of the
median canal is not well indicated, nor the wide midrib, especially

prominent on the back of the pinnule. The origin of the nervils in
the median strand is well represented.

(132)

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA
Vol. 4, pp. 133-H6 February 25, 1893

SOME ELEMENTS OF LAND SOULITI'IJK

BY LEWIS EZRA HICKS

{Offered to the Society for Publication August 15, 1892)

CONTENTS

Pago

Introduction l;;:;

Relief Forme subject to fixed Laws 133

Predominance of Curves, over Angles 134

SI ructural Angles 134

• Character of Hock governs Form 134

Incessant Activity of sculpturing Forces 134

Flatness characteristic of continental Blocks 134

Weather Curve and water Curves 135

Weather Curve 135

Convexity of weather Curve 135

Water Curves : horizontal and vertical 136

Concavity of water Curve 136

Combined weather Curve and water ( !urve 137

Reversed Curves 138

Gilbert's "Exception" explained 3 38

Water Curve of Deposi t ion 142

Alluvial Cone 142

Flood-plains 142

Cross-section of constructive River .... 14:;

True Form of Cross-section 1 44

Cross-section of River having no Flood-plain 144

Anomalous Valleys of the great Plains L45

Summary 14<>

Introduction.

Relief Forms subject to fixed Laws. — Every element of form which gives
character and expression ton landscape is determined by fixed Laws. It
is true that the arrangement of lulls and vales does not conform to any
simple geometric pattern. The sculpturing forces are complex, and the
net result of their interaction is necessarily also complex and promis-

XX— Bull. Geol. Soc. Am., Vol. I. 1892. (!.'!:>)

134 L. E. HICKS — SOME ELEMENTS OF LAND SCULPTURE.

cuous; still the action of each single force is regular, exact and unvary-
ing, and the complex results are harmonious.

Predominance of Curves over Angles. — Most pleasing to the eye are those
forms in a landscape which arc bounded by curved lines and surfaces.
Most striking, picturesque, rugged and impressive are those which are
hounded by planes and angles. The former arc far more common, and
are produced by weathering and the washing of water. The latter de-
pend upon the primitive structure of the rocks. Angular structural"
forms are the rough blocks which nature furnishes. Wind and frost.
sun and rain, rills and rivers, are the tools which carve out of these
rough blocks the beautiful landscapes which adorn the earth and make
it a fit abode for man.

Structural Angles.

Character of Rock governs Form. — The laws of structure are intricate.
and structural forms are infinite in variety. The planes may face in
any direction, the angles may be acute or obtuse. That depends wholly
upon the forces of upheaval and the laws of fracture in the different
rocks; granite, limestone, basalt, conglomerate, each imparts a definite
and characteristic expression to the landscape, because each breaks in a
way peculiar to itself.

Incessant Activity of sculpturing Force*. — But with all this variety in de-
tail there are certain broad, general features of structure which exert an
important influence in the evolution of earth forms. The pent-up forces
within the earth thrust up from time to time fresh blocks, to be disinte-
grated by the weather and carved by running water. ' These sculpturing
forces never rest, while the forces of upheaval are intermittent. This
incessant and universal activity of the sculpturing forces is the reason
why the pleasing forms hounded by curves are more common than rough
structural angles.

Flatness Characteristic of continental Blocks. — Though the internal forces
are inconstant they are mighty. Mountains and continents are the
burdens which they lift with ease. The lands are lifted and at the same
time broken, faulted, bent and tilted this way and that. The resulting
planes may slope north, south, east or west, and the pitch may be steep
or gentle. Very steep structural planes are. however, of limited extent,
while the great continental blocks must of necessity lie nearly flat,
though the edges may lie precipitous. Broad, flat blocks are therefore
the usual raw materials for the sculpturing forces, and the resulting
weather and water curves are dominated by these massive and nearly
level, primitive elements of structure. Massive breadth and relatively
slight inclination of the general surface are the fundamental character-

STRUCTURAL CURVES AND THEIR PRODUCTION. 135

istics of structure which prevail in the midst of the infinite variety of
relief forms.

Weather Curve and water Curves.

Weather Carre. — The weathering of structural blocks reduces their
salient angles, which are attacked from both of the adjacent faces at once.
At the point x, figure 1, the disintegrating forces act with twice as great
intensity as at b, since the attack conies from two directions. The effects
are more than twice as great at x, because the products of decay are
quickly removed, exposing fresh surfaces to the attack, while at b they
remain to cover and protect the subjacent beds. Thus the structural
block m n o p is rounded oil' by weathering. The new outline a b c is
composite. The portion <1 b e is ;i weather curve, convex upward. If
weathering alone, without the aid of flowing water, has been concerned
in the sculpturing process, the talus slopes a d and e c will be structural
planes, not curves. The structural angle e c p will he determined by the

am j> c

FtiiUHE 1. —Weather Curve.

resting angle of the materials composing the talus, and that again will
depend upon the size and form of the particles ; hut in humid regions
the talus slopes will he quickly molded into water curves, as hereaiter
described. The resulting form <i b c will lie a rounded rock, a smooth
knob, or a round-topped hill or mountain, according as the original block
was measured by inches or leagues.

Convexity of weather Curve. — The upward convexity of weather curves
may be deduced also from the law Hint declivities vary directly as hard-
ness. If we suppose the lowest beds composing a structural block to he
very soft and the hardness to increase upward by regular gradations, ;i
concave slope would result. Such a curve may actually be formed, hut
it would have to be ascribed to structure, not to weathering. Weather
curves are often interrupted and modified by such structural accidents.
But if the opposite conditions prevail — that is to say, if the soft bed is
above and the hardness increases regularly downward -the law just
enunciated will yield a slope of convex curvature. Now, whatever may

130 L. E. HICKS — SOME ELEMENTS OF LAND SCULPTURE.

be the primitive conditions of hardness in structural blocks, the tendency
of weathering is to soften them from the top downward, or, in other
words, to produce that set of conditions last supposed; hence the
weather curve should be convex upward.*

Water Carres: horizontal and vertical. — The streams formed by the
rains falling upon continental blocks have still greater sculpturing power
than the weather. The rough edges are first scored down with ravines,
as a carpenter hacks timber with an axe before he dresses it with finer
tools. Some of the ravines lengthen into rivers and cut far back into the
land. Except raw and fresh ravines, which may be tolerably straight,
the path of flowing water is meandering. Graceful serpentine curves
mark the flow-line, curves which constitute the most charming elements
of scenery. These horizontal water curves address themselves to the eye
in the most clear and agreeable manner ; but there is another kind of
water curve, the vertical, not always visible to the bodily eye, but none
the less clear and real to the eye of the mind. If we follow up a short

Figure 2. — Water Curve of Erosion.

ravine cut in homogeneous material we shall find a gentle slope at first.
which gradually increases in steepness up to the crest of the escarpment.
The positions of successive points of the channel, with their true rela-
tive distances above base-level, if drawn to scale, would form a curve like
figure 2. This is the typical water curve of erosion.

Concavity of water Curve. — The water curve is precisely opposite to the
weather curve, in that it is concave upward. In a short ravine it may
be plainly seen, but the vertical curve of a river is so much flattened and
extended that it can only be comprehended by the mind, not perceived
by the eye. Indeed, there is a sense in which this vertical water curve,
as defined by Gilbert, La Noe and Margarie and others, is not only im-
perceptible but purely ideal. It is seldom realized as a smooth curve.
uniformly increasing its gradient upstream, except for short streams
whose channels are cut in a homogeneous rock. The intervention of a
harder stratum makes a jog in the curve. All cataracts and rapids with

♦ Compare La Noe and Margarie, " Formes du TerraiD," p. 26, pi. vii, fig. 15.

STRUCTURAL CURVES AND THEIR PRODUCTION. 1 37

still water above them are in flat contradiction to the law of increasing
gradient upstream and skyward concavity. Time enough being given,
the obstruction would no doubt he cut through and the ideal curve
established. All streams tend toward its realization as an ultimate goal.
Cataracts are temporary departures from the rule, and quite evanescent
when compared with the whole life history of a river.

Combined weather Curve and water Curve. — Another departure from the
type is more permanent and universal, so frequent and lasting, indeed,
that it almost deserves to he formulated as a distinct and opposite law.
it is the fact that while the gradient increases upstream to a certain
point and the curve is concave upward, as the definition requires, above
that point the gradient diminishes, and the curve is convex upward, as
at a />, figure 3. This is usually true of streams rising in extensive
swamps and wet meadows. Even the mountain streams often flow
sluggishly at first upon broad Hat summits, then pitch headlong over the
escarpment. We have seen above that breadth and flatness are the domi-
nant elements of structure. The precipitous edges of broad continental

Figure 3.— Combined weather Curve (a b) and water Curve (b c).

blocks being rounded off impose their own curves upon the rivers. Thus
the convex portion (a 1>, figure 3) is not really a water curve, it is a
temporary accommodation of a water gradient to the structural form
upon which it flows. The true water curve (b c, figure 3) will moreover
gradually encroach upon the upper convex curve a b, and, if the base- *
leveling be continued long enough, it will establish itself as a smooth
concave curve from c to a. Hence this exception, as in the case of cata-
racts, is an incident only of river history, the only differences being that
it is more common and less transient; but, as 1 said above, it almost
deserves to take rank as a distinct and coordinate law on account of its
universality. The convex portion of the curve (a />, figure 3) is not,
however, a new kind of curve, but one that has already been defined,
viz, the weather curve. The double reversed curve (a /> c, figure 3) is the
combination of the weather curve and the water curve of erosion. It is
Hogarth's line of beauty, the most universal of earth forms. Almost
every hill slope in a rolling country presents an upper convex portion

138

L. E. HICKS — SOME ELEMENTS OF LAND SCULPTURE

(weather carve) and a lower concave portion (water curve). Some land-
scape engineers have caught nature's hint and give a terrace the form
shown in figure 3, which' is at once more elegant and more solid and
durable than a slope in which the convexity is carried uniformly down

Figure 4. — Unstable artificial Curve.

to the base, as in figure 4. The latter is unnatural and unstable, while
the former is natural and stable.

Reversed Carre*. — Tins combination of the weather curve with the ver-
tical water curve of erosion when carried out upon both sides of a struc-
tural block (as m a <> j>. figure 1), which is symmetrical and homogeneous,
will give the pair of reversed curves shown in figure 5, instead of the

Figure 5. — Normal relief Form in an advanced Stage 0/ Base-leveling.

simple convex weather curve db e, figure 1. Figure 5 is the normal
pattern of relief forms in a region of advanced land sculpture. The
summit b a b is a simple, typical weather curve. The talus of figure 1,
with its clear-cut structural angle, e c p, has been replaced by the vertical
water curve b c (figure 5), which is concave upward.

Gilbert's "Exception" explained. — This same combination of weather
and water curves is the true explanation of the li exception " noted by
Gilbert* who states :

" There is one other peculiarity f of bad-land forms which is of great significance,
hut which I shall nevertheless not undertake to explain. According to the law of

Figi re 6. — Typical Profile of the drainage Slopes of Mountains.

* Report oii the Geology of the Henry Mountains, pp. 122-123.

t Figure 6, which is a reproduction of Gilbert's figure 54 (ibid., ]>. 116), shows an angle. Such
would be tin- actual result of intersecting water curves bui for tin- effed of weathering, which

rounds oil' the angle and replaces it by a curve convex upward.

Gilbert's exception to law of divides. 139

divides, as stated in a previous paragraph, the profile of any slope in the bad-lands
should be concave upward, and the slope should be steepest at the divide. The
union or intersection of two slopes on a divide should produce an angle [figure 6].
But in point of fact the slopes do not unite in an angle. They unite in a curve, and
the profile of a drainage slope, instead of being concave all the way to its summit,
changes its curvature and becomes convex. . . . From a to m [figure 7] and
from b to n the slopes are concave, but from m to n there is a convex curvature.
Where the flanking slopes are as steep as represented in the diagram, the con-
vexity on the crest of a ridge has a breadth of only two or three yards, but where
the flanking slopes are gentle, its breadth is several times as great. [Compare
figure 5 with figure 7.] It is never absent.

Fku'kk 7. *— Cross-profile of bad-land' Divide.

" Thus in the sculpture of the bad-lands there is revealed an exception to the
law of divides, — an exception which cannot be referred to accidents of structure,
and which is as persistent in its recurrence as are the features which conform to
the law, — an exception which in some unexplained way is part of the law. Our
analysis of the agencies and conditions of erosion, on the one hand, lias led to the
conclusion that (where structure does not prevent) the declivities of a continuous
drainage slope increase as the quantities of water flowing over them decrease, and
that they are great in proportion as they are near divides. Our observation, on
the other hand, shows that the declivities increase as the quantities of water
diminish, up to a certain point where the quantity is very small, and then de-
crease; and that declivities are great in proportion as they ai'e near divides, unless
they are very near divides. Evidently some factor has been overlooked in the
analysis, — a factor which in the main is less important than the flow of water, but
which asserts its existence at those points where the flow of water is exceedingly
small, and is there supreme."

The missing factor is a simple and omnipresent one, namely, weather-
ing. From a to m the water curve predominates, and its law of skyward
concavity and increasing declivity is supreme. From m to h the weather
curve predominates. As Gilbert remarks, "the flow of water is exceed-
ingly small" there. It falls as rain and beats upon the crest, hut that is
a kind of weathering.

Besides supplying the missing factor which explains the puzzle and
reconciles the results of scientific analysis with the facts as learned by

* Figure 7 is a reproduction of Gilbert's figure 60, in his Report on the Geology of the Henry
Mountains, p. 123.

140 L. E. HICKS — SOME ELEMENTS OF LAND SCULPTURE.

observation, I will add two observations suggested by the above quota-
tion.

In the first place, the remark of Gilbert that "where the Hanking
slopes are as steep as represented in the diagram, the convexity on the
crest of the ridge has a breadth of only two or three yards, but where
the flanking slopes are gentle, its breadth is several times as great,''
conveys a partial truth, and at the same time suggests a broader truth.
Gilbert merely affirms a relation between the steepness of the decivities
and the breadth of the convex portion of the crest; but both of these
correlated elements of form depend upon the relative intensities of water
sculpture and weathering, and these in turn depend upon the struc-
ture and the stage of base-leveling in the given region. The general
law of relative intensities may be stated as follows: If water sculpture
predominates, the slopes will be steep and the divides narrow and high ;
and, conversely, if weathering predominates, the slopes will be gentle and
the divides broad and low; but this general law is profoundly modified
by structure and time. The broad, flat blocks which, as we have seen

ct

Figure 8. — Illustrating the Co-i cistt nee of steep Slopes with broad weather Curves in an tarty Stage of

Base-leveling.
fi«() = weather curve ; b c = water curve.

above, are the normal types of raw material to be moulded by land
sculpture, yield broad weather curves in the early stages of base-leveling
wholly on account of their primitive structure. This is an exception to
the general law, inasmuch as water sculpture is usually energetic in these
early stages, and yet the weather curves are 1 >r< >ad. 1 1 is als< » an exception
to Gilbert's statement that the crest is narrow if the slopes are steep.
Many cases occur in the earlier stages of base-leveling in winch broad, flat
weather curves are conjoined with very steep water curves, as in figure 8.
Many cases also occur in the same early stages of base-leveling in which
the crest is narrow and the slopes steep, as affirmed by Gilbert and illus-
trated by his figure G'>. For example, the same mesa represented in
cross-section by figure 8 would present many subordinate ridges between
its lateral ravines with steep slopes and narrow crests. It is evident,
therefore, that in this early stage of base-leveling, structure is the domi-
nant factor whether the crest is narrow or broad. The steep water
curves are the direct result of structure, since it is only by upheaval

EXPLANATION OF GILBERT'S EXCEPTION. 141

that such high gradients originate; and the broad crests are equally the
direct effects of structure. The narrow crests exemplify the law of rela-
tive intensities, as stated above. Water sculpture is more energetic than
weathering upon the precipitous edges of structural blocks; hence the
slopes are steep and the crests narrow.

With the lapse of time the influence of structure gradually diminishes,
and the stage which base-leveling has attained exerts the greater modi-
fying influence upon the general law. In other words, time exerts a
modifying influence in proportion to its quantity, measured from the
beginning of the process of 1 rase-leveling. If this process has just begun,
structure is supreme; but if it has reached its later stages the accumu-
lated effects of time are supreme. Weathering and water sculpture both
tend to become less energetic as the surface approaches base-level and the
gradients flatten out, but the former retains a greater relative efficiency.
The transportation and removal of the solid products of weathering does
indeed steadily diminish, but solution — one form of weathering — and the
transportation of its products goes on to the very last stages of land
sculpture, after erosion has ceased. These last stages are therefore marked
by water curves of slight declivity and weather curves of great breadth
and flatness, both in fact closely approaching, but never quite reaching,
an absolute base-level.

The general law with its modifications ma}r be summed up thus : In
early stages of base-leveling the predominance of water sculpture' gives
steep slopes and narrow crests, except where the latter have a breadth
which is imposed upon them by the structure, and in late stages of base-
leveling the predominance of weathering gives water curves of gentle
declivity and broad, low weather curves.

The second observation suggested by the quotation from Gilbert is
that the principles explained by him as applying to "bad-land forms "
are equally applicable to all kinds and all stages of land sculpture. Bad
lands constitute a certain striking phase of land sculpture, but they are
nowise exceptional, so far as the general laws and processes of land sculpt
ture are concerned. All of the factors are present and active. The resul-
is unique, not because of the absence of any familiar factor nor because
of the presence of any new factor, but solely because of the relative
intensity of the factors. Structure and water sculpture strongly predomi-
nate over weathering. Structural forces have supplied the canon clays
and marls as raw material — a matrix soft, homogeneous and peculiarly
susceptible to rapid erosion on account of these properties and its con-
siderable elevation. Water sculpture, attacking it with an energy pro-
portional to its height above base-level and its lack of cohesion, cuts deep
gashes so rapidly that weathering has little opportunity to round off the

XXI— Bull. Geol. Soc. Am., Vol, i, 1882.

142 L. E. HICKS — SOME ELEMENTS OF LAND SCULPTURE.

sharp edges. Indeed, this important factor occasionally seems, for the
time being, to be wholly wanting. Forms like figure 9 are not uncommon
in the bad lands. The summit b b is protected with turf and the water
curves b c extend to the very crest without a trace of a weather curve;
but the elimination of this factor is transitory. Visit the same butte
some years later and you will find, if water sculpture is still vigorous,
that the two water curves have so nearly joined that the turf has dis-
appeared and a short weather curve occupies the narrow crest, as in
figure 7 (Gilbert's figure 60), or, if water sculpture has been dormant, the
angles b b are replaced by weather curves. In a bad-land region all
stages of the process may be observed, from the level-topped sharp-angled
butte, often receiving the significant name " Box butte " or " Trunk butte,"
shown in figure 9, to low domes like figure 5, which are not bad-land
forms at all. The same laws, the same processes are concerned in all
these varied results,'and a philosophic view of the subject demands that

Figure 9.— Miniature Butte in tlie Bad Lands.

all phases and stages of land sculpture be grouped comprehensively
instead of singling out a particular phase, though that maybe a striking
one.

Water Carve of Deposition. — The water curve of erosion, having its sky-
ward face concave, is not the only vertical water curve. There is also
the curve of deposition, which is convex upward. Where a mountain
torrent debouches upon the plain, the debris carried or rolled along by it
spreads out in a mass which is fan-shaped in ground plan and conical in
elevation.

Alluvial Cone. — Such a deposit is usually called an alluvial cone, but,
in view of its radial extension from the mouth of the gorge, Hilgard calls
it a debris fan. The cross-section presents a typical water curve of depo-
sition, convex upward.

Flood-plains. — The flood plains of rivers, so far as they are built up by
sediment spreading laterally from the channel during floods* follow the

* This is the usually accepted meaning of the term flood plain, namely, that it is the work of a
constructive river which is silting up its valley, or certain portions of it, during inundations. Gil-
bert uses the term in a very different sense. He says in Geology of the Henry Mountains, p. 132:

"* * flood-plains are usually produced by lateral corrasion. There are instances, especially
neai' the seacoast, of river plains which have originated by the silting up of valleys, ami have been
afterward partially destroyed by the same rivers when some change of level permitted them to

FLOOD-PLAINS. 14

I v

same law. It is true the curvature is faint, so faint that in the field it
may he imperceptible to the eye, and in diagrams most authors ignore
it, and represent the cross-section of a flood-plain by a straight line; but
the curve, though slight, is real. If compared with the debris fan of a
mountain torrent it would be found to correspond to the outer margin,
where it blends into the plain and the convexity is slight. Strictly
speaking, a flood-plain extending many miles along a river cannot be
likened to a single alluvial cone; it is a composite structure made up of
a multitude of overlapping cones, each having its apex upstream at that
point where the silt composing it left the channel. The overlaps obscure
the convexity of individual cones, and the net result is a curve of large
radius and low convexity.

Cross-section of constructive River. — The typical cross-section of a river
having a flood plain — a constructive river— so far from showing a straight
line from the channel to the bluffs, presents a convex curve of deposition,
besides a number of other distinct elements. If no terraces are present
the section will be as in figure 10, each half of the valley presenting a

Figure 10. — Cross-section of a constructive Rivt r.

a b = Weather curve at crest of bluffs ; ic^= Water curve of erosion ; e d = Swamp ; de= Water
curve of deposition.

weather curve, two water curves of opposite character, and a swamp
along the line of intersection of the water curves. The presence of ter-
races adds much complexity. The swamp at c d is caused by a de-
pressed surface and an impervious subsoil. Only the finest argillaceous
sediments spread so far from the channel or from the bluffs, and these

cut their channels deeper; and these instances, conspiring with the fact that the surfaces of flood
plains are alluvial, and with the fact that many terraces in glacial regions are carved from uncon-
solidated drift, have led some American geologists into the error of supposing that river terraces
in general are records of sedimentation, when in fact they record the stages of progressive cor-
rasion."

The question about the true significance of terraces is aside from the present discussion, but the
ordinary meaning of flood-plain is too well settled to disturb it by so radical a departure as that
here proposed. Since Gilbert himself admits it to be descriptive of'a real phenomenon, we might
conclude that there are two kinds, flood-plains of eorrasion and flood-plains of sedimentation, and
that all we need is to distinguish these and use the term in each case with its proper adjunct; but
a closer analysis reveals two difficulties. In the first place, since tin' products of eorrasion on one
side of a stream are deposited as sediments on the other side, it turns out that the plain of cor.
rasion, or planation, is also a plain of sedimentation. This difficulty tends to merge the two kinds
into one ; but there is an opposite and more radical difficulty which rends them apart. The plain
of planation is not properly a flood-plain at all. Lateral eorrasion is nut exclusively a flood phe-
nomenon, though it is active in floods. The plain of planation differs so much from true flood de-
posits that the term flood plain ought to he restricted to the latter, as is usually done,

144 L. E. HICKS — SOME ELEMENTS OF I. AND SCULPTURE.

form a gumbo * which imparts the impervious quality to the subsoil, and
at the same time their small bulk and relatively slow growth occasions a
line of depression. Even when well drained, this part of the river bottom
is apt to be cold and sour mitil redeemed by tillage and the admixture
of silicious elements.

True Form <;/' Cross-section. — The old definition of the upper course of a
river postulates a V-shaped cross-section.. This is not strictly true, even
of fresh ravines at the headwaters. The sides are water curves of erosion,
and they conform to the general law that the slope varies inversely as
the quantity of water flowing upon it. Since the bottom of a slope re-
ceives the water from above as well as its own quota of the rainfall, its
pitch must always be less steep than that above if it is a true water
curve. One side of a ravine may be ;i talus with its sharp structural
angle and uniform declivity, the corrasion at its base proceeding so rap-
idly as to give no time for a water curve to form. Very rarely, when the
bottom only of a ravine is undergoing erosion, a talus slope may exist on
both sides, and the section will then be accurately V-shaped; but if the
corrasion at the base of either wall lags or stops, the wash of that slope
will speedily convert it into a concave water curve of erosion. The actual
result is usually composite, including elements or remnants of a structural
angle, modified by a water curve. At all events, it is a curve rather than
an angle, and a V with curved sides quickly passes into a U. The middle
course of a river is usually said to have a U-shaped valley, hut in fact
this form belongs to all parts of a river, the onl}' difference being the
breadth of the U. It is in the upper course alone that it has anything
like normal proportions. In the middle, and especially in the lower
course, it sprawls out and flattens down until all resemblance to the fifth
vowel is lost. Moreover, the presence of terraces and water curves of
deposition so complicates the cro<s-section that the comparison of it with
any letter of the alphabet is no longer useful.

Cross-section of River having m> Flood-plain. — The most important real
distinction between the different parts of a river valley is the presence or
absence of a flood-plain. If this is present the section will he as in figure
10; if it is absent, it will be as in figure 11. in which, as compared with
figure 10, the middle portion, including the flood-plain with its convex
curvature, has been cut out.

There is a wide range of variation among different rivers in that por-
tion of the valley which has a cross-section like figure 11. It may he
very narrowly U-shaped, or it may open out to such breadth as to he-
come anomalous. Under ordinary climatic and geologic conditions the

*Gumbo is a peculiar, tenacious, fine-grained clay. The use .-mil meaning of this term in the
western states is so well established, that it promises t" become a useful and expressive word. '

ANCXMALOIS STRUCTURAL FORMS.

L45

narrow U-form would include the whole course of the river above the
initial flood plain.

Figure 11.— Cross-section of a river Valley having no Flood-plain.
Each half of the valley has only two elements, the weather curve a b and the water curve b c.

Anomalous Valleys of the great Plains. — But certain peculiar conditions
sometimes intervene to prevent the development of a Hood plain where
it normally belongs. Then we have the anomaly of a valley some miles
in breadth without a flood-plain, which is so diametrically opposed to
our ordinary conceptions of rivers that we are at once impelled to seek
its explanation. It is upon the great plains at the eastern base of the
Rocky mountains that we find the most striking examples of wide valleys
without flood-plains. The lower part of the water curve (m n, figure 12)

Figure 12. — Cross-section of a broad Valley of the Plains having no Flood-plain,
a l> = weather curve ; b m n = water curve, of which the lower portion, m ??, is greatly extended.

may be a mile or two in breadth. At the point m the valley wall begins
to be well defined. The valley floor m m is also well defined, but quite
remarkable for its wide departure from horizontality. The point m may
be fifty feet above n. It is unmistakably a valley floor, but its steepness
is astonishing and perplexing. Moreover, the anomaly does not stop with
the unusual form of the cross-section. The quality of the land contra-
dicts all expectations which would naturally be entertained respecting
river bottoms. Instead of a uniform stretch of rich alluvium we find
irregular alternations of loam, sand, gravel, gumbo and alkali patches.
The best element, the loam, may indeed predominate, and hence the
valley may support a prosperous agriculture; but the valley lands of the
plains are generally inferior to the table lands, thus reversing the condi-
tions which usually prevail.

The plains are built up of incoherent masses of sand, gravel, (day

Idb' L. E. HICKS — SOME ELEMENTS OE LAND SCULPTURE.

and marl, in which the rainfall is absorbed and reaches the rivers by
slow percolation, instead of flowing quickly and copiously On the sur-
face; hence, if there are any floods at all. they are infrequent and
irregular. Without regular floods there can he no distinct flood-plain,
the silt deposited during the rare overflows being obscured and sub-
ordinated to the heterogeneous wash from the hills. The patchy char-
acter of the soil arises from local conditions affecting the wind drifts and
washings from the bluffs, bringing down here gravel, yonder sand, and
again the mingled silicious. calcareous and argillaceous elements consti-
tuting loam. Alkaline carbonates and sulphates are developed in low,
undrained spots, where water lies and evaporates. By the meanderings
of the channel the valley floor is plowed up and redeposited, but this
process tends to still greater differences rather than greater uniformity.
The assorting action of the currents segregates the coarser and finer ele-
ments and deposits each by it-self. The absence of floods intensities and
perpetuates these diversities. No general 1 danket of rich silt is spread in
annual layers to cover and blend into one the heterogeneous soils, nor
do the copious waters spread over the alkali patches to dilute and wash
out their bitterness. Thus arise these anomalous, wide valleys without
flood-plains, in which the whole valley floor from the bluffs to the
channel on either side slopes sharply inward, and the soils are patchy
and wholly unlike ordinary bottom lands.

Summary.

This paper makes no pretensions to an exhaustive treatment of the
elements of land sculpture. There are other forces at work, and the forces
named operate in ways not herein discussed in detail; but in the broad,
general view of the subject the face of nature is moulded chiefly by these
forces : (1) Upheaval, which furnishes the structural blocks to be chiseled
into pleasing forms ; (2) Weathering, which rounds off the asperities and
covers the land with graceful, swelling curves; (3) Washing of water.
which yields concave flowing lines upon slopes of erosion, and low con-
vex curves of deposition.

The combination of the weather curve with the water curve of erosion
is here noted and explained for the first time. It constitutes the greatest
charm of natural landscapes, and its effects are universal.

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA
VOL. 4, PP. 147-166, PL. 2 FEBRUARY 25, 1893

SOME DYNAMIC AND METASOMATIC PHENOMENA IN A

METAMORPHIC CONGLOMERATE IN THE

GREEN MOUNTAINS *

BY CHARLES LIVY WHITTLE

(Presented before the Society August 16, 189%)
CONTENTS

Page

Metamorphic Conglomerate 148

Approximate Relation to known geologic Horizon 148

Ottrelite Schist 148

. Occurrence and Extent 148

Physical and microscopic Characters 140

Mineralogic Constituents 150

Parallel Grouping of ottrelite Prisms 151

Parallel Grouping of rutile Grains ■ 152

Alteration of Ottrelite into Chlorite 152

Relation of the two Minerals 152

Optical Characteristics 153

Groundmass of the Rock 153

Mineralogic Constituents 153

Feldspar 153

Sericite 153

Anatase. 153

Rutile 154

In General 154

Order of Crystallization 154

Metamorphism of the clastic Material in conglomerate Phase 155

Occurrence • • 155

Character of the Rock 155

Secondary Enlargement of clastic Tourmalines 156

Two Periods of Disturbance indicated 158

Alteration of clastic Feldspars 150

Clearing Action of growing Sericite 160

Alteration of clastic Microcline into Plagioelase 161

Chlorite Schist and Phyllite 164

Their Plications built into secondary Albites L64

Composition of the Groundmass 165

* Published by permission of the Director of the IT. 8. Geological Survey.
XXII— Bull. Geol. Soc. Am., Vol. 4, 1892. (147)

148 C. L. WHITTLE METAM0EPH10 CONGLOMERATE.

Metamorphic Conglomerate.

Approximate Relation to known, geologic Horizon. — The geologic position
of the limestone and quartzite of the Rutland valley has lately been de-
termined definitely,'1' the limestone paleontologieally and the quartzite
stratigraphically.

Occurring next below the limestone, the quartzite is the northern
continuation of the Clarksburg-mountain quartzite, in Massachusetts,
in which Walcott has found the Olenellus fauna characteristic of the
Lower Cambrian horizon. About one mile north of Rutland village, in
Vermont, Dr Wolf and Dr Foerste were fortunate enough to find Lower
Cambrian fossils in a silicious limestone that lies superjacent to the
quartzite. Northeast of Rutland the quartzite is found associated with a
sandy phyllitic schist that belongs to a series of metamorphosed elastics
having a vitreous quartzite or conglomerate at its base. This whole
series, barring the Lower Cambrian quartzite and limestone, has been
subjected to the most intense dynamic action. The sequence of the dif-
ferent members of the series is in many regions hopelessly obliterated
and confused by the mountain-building forces that have produced new
structural planes, a new mineralogic composition, and have additionally
complicated the geologic order of succession by sharp folding, which is,
as a rule, too much involved for decipherment. These phenomena are
particularly noticeable in the conglomerate horizon and its many phases,
and it is in this rock that I wish to describe some of the evidences and
effects of metamorphism shown by the destruction of old clastic minerals
and in the production of new ones.

OTTRELITE SCHIST.

Occurrence and Extent. — One of the most conspicuous phases of the con-
glomerate is due to the development of ottrelite in great abundance, so
that it is not uncommon to find fully 25 per cent of the rock made up of
this mineral. The ottrelite is commonly most abundantly developed
where the rock has now a well-marked schistose character that is either
due to an original finer-grained deposit or is a result of the shearing and
crushing action of dynamic forces. It is often found, however, occurring
in the grouudmass of the coarsest conglomerate or along planes of shear-
ing in a blue, hyaline quartzite. Still another phase is more nearly mas-
sive, fully 40 per cent being ottrelite, the rock at first sight simulating
in appearance some porphyritic hornblende dike. The rock is a very

*"0n the Lower Cambrian Age "t the Stoekbridge Limestone" : Bull. Geol. Soe. Am., vol. •_. 1880
pp. 331-338.

LOCALITY AND CHARACTERISTICS. 149

variable one, but, considered as a whole, it forms one of the most impor-
tant stratigraphie horizons found in the more crystalline areas of the
Green mountains. In lateral extension it has been traced, with unim-
portant breaks, all the way across the Green-mountain anticlinal axis,
as mapped by Hitchcock * from Mendon, Vermont, to North Sherburne,
Vermont. In vertical extension it has considerable thickness, although
accurate determination is very difficult, owing to the obliteration of planes
of bedding in most instances and the complexity of the flexures; but it
seems safe to assume a thickness of several hundred feet, at least in sev-
eral localities that have been most carefully studied, viz : a spur extend-
ing south from Mount Carmel, in the town of Chittenden, and the east
and west crest forming the southern portion of the mountain, somewhat
inappropriately named "Old Aunt Sal."f The latter mountain is situ-
ated in the town of Mendon, the next town south of Chittenden. The
phases studied thus far in the laboratory are from this latter locality
and from the western part of the " Rabbit ledge," just south of Mendon
" city."

Physical and microscopic Characters. — In the hand specimen the ottrelite
of the most massive occurrence of the ottrelite-1 tearing rock appears either
as isolated areas, generally with rudely circular outlines, or as groups of
them in a background of fine-grained pinkish-brown to dark-purple
quartz, in places constituting nearly pure ottrelite. These areas possess
approximately a common diameter of about three-sixteenths of an inch.
In structure the}'' are made up of radiating imbricated plates generally
arranged in essentially one plane for any single area ; but the positions
of the different areas seem in the main to be accidental, although locally
they may be arranged parallel, as shown by a tendency in the rocks to
cleave into rude slabs, a tendency augmented by thin folia of serecite.

A well marked spherocrystalline habit characterizes all the ottrelite
areas. In some this radiated growth seems to be perfect. Microscopic-
ally the radiated structure is much more evident. Composite and fan-
shaped areas, penetrating one another irrregularly, coexist with isolated
prisms and beautiful spherocrystalline aggregates, yielding imperfect
crosses in polarized light. Only sections cut parallel to the bundles of
plates (basal sections) show well the radiated structure ; all other sec-
tions show this character less and less, depending upon the plane of the
section, until it is transverse, when the mineral appears prismatic. The
areas of spherocrystals are not infrequently bounded by overlapping six-
sided plates, of which three are usually free; the others are intergrown
and confounded in thy central position of the aggregate.

* Figure 4, section vi, Hitchcock's Green mountain gneiss, G-eoI. of Vt., vol. 4. 1861.
fThe name Blue Ridge is given this mountain on the Rutland topographic sheet completed in
1891, butl have decided to use here the most commonly adopted local name

150 C. L. WHITTLE — METAMOE.PHIC CONGLOMERATE.

The extreme mobility of the ottrelite-bearing solution is indicated by
the manner in which the ottrelite needles have insinuated themselves
into included feldspar grains along no visible lines of fissuring.

Mineralogic Constituents. — As in all described occurrences of this min-
eral, an abundance of inclusions exists. It is noticeable that, while quartz
and occasionally feldspar are included, sericitc. which is the principal
micaceous constituent of the rock, is seldom enclosed by the growing
ottrelite. but may be wholly or in ]>art the nucleus about which an ag-
gregate formed. Such nuclei seem in some cases to have governed the
growth of the ottrelite. There was a tendency as the mineral formed for
the plates to orient themselves parallel to the sericite nucleus, so that
when such a nucleus is surrounded by basal ottrelite it is apt to be basal
also. Whether this is another example of parallel growth or is acci-
dental I cannot state definitely. By far the most abundant interposi-
tions are a multitude of extremeW minute black to brown dots and
aggregates. With a number 7 objective these are resolved, in the main,
into rutile, occurring in knee-shaped and heart-shaped twins, but gen-
eralhr in rounded forms, in which twinning is not distinguishable. In
other cases the highest objectives are incapable of individualizing the
grains, as is mentioned by Renard* In some crystals the rutile is
grouped in reticulated lines conforming rather rudely to the planes of the
two principal cleavages, but as a rule it is grouped along irregular lines
that traverse the ottrelite and the groundmass alike. It may have been
arranged originally in structural lines, developed along planes of bed-
ding, that afterward were built into the ottrelite with total disregard of
any observed relationship, in the same manner that quartz and feldspar
droplets were built into albites in another phase of this rock. Other
inclusions are graphite (determined by deflagration) and little coffee-
brown ilmenite plates (titaneisen glimmer). A powerful current from
an electro-magnet applied to that portion of the powdered rock which
ran through a 120-mcsh sieve attracted but a little of the particles, so
that magnetite and probably ferrous oxide are absent. The usual test
for titanium gave a positive reaction.

As in biotite and chlorite, pleochroic zones about crystals of zircon are
very common in the ottrelite, and their characteristic dependence of
maximum pleochroism upon the maximum pleochroism of the enclosing
mineral is observable. While zircon usually occupies the centers of these
zones, other zones occur having no perceptible associated inclusion."f

♦Researches sur la Composition et la Structure des Phyllades Andennes. Phyllade i »ttrelit6fere
do Montherme. Bulletin du Mus6e D'Hist. Nat. de Belgique, vol, 3, 1884-85. p. 252.

1 1 am disposed to refer the brown material making these z ss to minute rutile grains. < ittre-

lite containing such zones was subjected to the temperature of a Hansen burner withoul destroy-
ing them, so they are probably of a mineralogic nature.

OTTRELITE PRISMS.

151

Although twinning with composition face parallel to 0 is not uncom-
mon in the ottrelite, a large part of what seems to be twinning is seen to
be clue to overlapping plates. As the stage is revolved the wavy extinc-
tion caused by this may be observed, — the usual spherulitic structure.

Parallel Grouping of ottrelite Prisms. — Examples of crystal growth set up
in several places at the same time occur in the rock where each part is
controlled by every other, resulting in an irregularly outlined prism com-
ix »sed of many individuals separated by areas of the grounclmass and
yet all oriented together (see figure 1 ). This phenomenon is unlike that

Figure 1. — Thin Section of ottrelite Schist. X 25.

Showing formation of ottrelite at many different points. Each small area is oriented with all the
others, forming a large area showing a general prismatic outline. The prism has been developed
transverse to the sehistosity of the rock. The background is largely gneissic quartz, with some
secondary feldspar. (Drawing from mierqphotograph.)

of andalusite, which occurs so frequently grown into large individuals,
enwrapping all other minerals of the background, but is another exam-
ple of independent parallel growth analogous to that of quartz in pegma-
tite, although in no way determined by the crystallographic position of
the minerals of the groundraass. Such growths are commonly developed
nearly at right angles to the layers of quartz and feldspar that make up
the sehistosity, and are usually freer from inclusions than the bundles.
They occur between the main areas of ottrelite and may represent a

152

('. I.. WHITTLE METAMOKPHK' ( < > XGLOM EB.ATE.

second generation. They were necessarily formed after the groundmass
was converted to a mosaic by granulation.

Parallel grouping qfrutile (Irani*. — Thesame phenomenon is noticed in
the rutile. Little yellowish-brown -rains of this mineral developed in
the interspaces of the minerals composing the background tend, although
made up of separate and sometimes isolated grains, to orient themselves
parallel to one another, forming groups having prismatic outlines. These
groups are only sparingly developed, but where observed they are gen-
erally parallel to one another* and to the sehistosity of the rock, and are
restricted in their occurrence, like the ottrelite individuals just described,
to the most quartzose parts of the rock, which they enclose in the same
manner as the ottrelite.

ALTERATION OF OTT 11 ELITE INTO CHLORITE.

Relation of the two Mineral*. — An interlamination of chlorite and ottrel-
ite was mistaken at first glance for either the contemporaneous forma-

Figuee 2.— Thin Section of Ottrelite. X 50.

Showing alteration o( ottrelite to chlorite.— A overlapping plates oi ottrelite; B = bifurcating
veins of chlorite allomorphosed after ottrelite and including cores of unaltered mineral ; C'= quartz
and feldspar mosaic. (From a microphotograph.)

* ( >wing to tin- great single refraction of rutile, their minute size, and tin- fart that they seldom
make tin' entire thickness of tin • section, it is difficuN to detect the agreement or disagreement of
their crystallographic position.

RELATION OF OTTRELITE AND CHLORITE. 153

tion of these minerals or an infiltration of chlorite parallel to the basal
cleavage of the ottrelite. Further investigation, however, showed that
the chlorite as often traversed the ottrelite irregularly in bifurcating veins
and enclosed parts of it (see figure 2). A study of the nature of these
veins convinced me that the chlorite is an alteration product of the ottrel-
ite. The edges of the veins where they traverse the ottrelite transverse
to the basal cleavage are jagged, the saw-like teeth projecting along the
composition faces or basal cleavage. The chlorite in such cases is dis-
tinctly made up of little fibers which have arranged themselves parallel
to one another and to one set of twinning lamella?. lanes of inclusion
once continuous in the ottrelite now stop short against interlaminated
areas of chlorite, showing the evident secondary nature of the latter min-
eral. In other places the chlorite is developed along the basal cleavage
of the ottrelite, leaves this cleavage and follows one of the prismatic
cleavages, and then again follows the basal cleavage, making one con-
tinuous line, thus producing steps, in much the same manner that garnet
commonly undergoes this alteration.

Optical Characteristics. — Cores of unaltered ottrelite remain in the chlo-
rite, and the pleochroic zones, once in the parent, are seen again in the
secondary mineral, while the relationship of maximum pleochroism of
these zones to the greatest pleochroism of the chlorite is handed down
as well. This metasomatic phenomenon has not been observed in other
phases of the ottrelite-bearing conglomerate thus far studied by me.

GROUNDMASS OF THE BOCK.

Mineralogic Constituents. — The background of the rock is composed of
quartz and feldspar as principal constituents.

Feldspar. — The feldspar is fresh and glass}7, untwinned, and is prob-
ably albite, but it is hardly abundant enough in the ottrelite bearing
phases to make the rock a gneiss even in mineralogic composition ;
and, structurally, a gneissic habit has been nowhere observed where
ottrelite exists to any extent.

Sericite. — Sericite is also abundant and occurs in minute prisms be-
tween the interlocking quartz grains and generally inclosed by the albite
but rarely by the ottrelite. It also incloses lines of rutile dots arranged
parallel to its cleavage planes, and next to the ottrelite it is the last
formed mineral.

Anatase. — Associated with rutile in the groundmass are groups of stout
and slender prisms and plates having a very high single and double
refraction and a variable color, from brownish-yellow to blue, even in the
same individual. These I identified as anatase. and for verification I

154 ('. L. WHITTLE — METAMOEPHIC CONGLOMERATE.

studied the sections described by Diller.* Unlike the anatase there de-
scribed, its occurrence in narrow prisms in this rock, together with its
rutile inclusions, seem exceptional. The stouter prisms have terminal
laces of an octahedron and range in size from one-fiftieth to three-iiftieths
of a millimeter in length. As the stage is revolved the pleochroism seems
only the intensification of the inherent color of the mineral — browns
becomine: browner and blues becoming bluer. The presence of rutile in-
clusions shows the anatase to have formed after that mineral and sug-
gests the probability of its being a paramorphic product of the rutile
inclusions.

Rutile. — Rutile dots and prisms exist in multitudes inclosed by all
other minerals of a secondary nature. They are so extremely minute that
even in a very thin section they focus in six or more different planes.

In General. — All traces of original clastic material in the rock have
disappeared ; feldspar detritus, if it once occurred, has been converted
into a mosaic of quartz, sericite, biotite and probably albite, and the
detrital quartz has been granulated. The existing feldspar is the char-
acteristic untwinned glassy variety carrying quartz and serecite inclu-
sions so common throughout this horizon, and was formed after the
granulation of the rock, since granulation could not have taken place
without straining or crushing it. Nearly all the quartz is sprinkled with
rutile inclusions, but it is noticeable that the larger areas have less of
them and may be cores that have escaped granulation. Its presence,
however, in such abundance militates against the probability of any of
the quartz being allothegenic and indicates rather its secondary nature.
In the same way quartz may inclose plates of micaceous ilmenite, but
does not inclose sericite.

There is evidence of a second period of this crushing force indicated
by a faint wavy extinction in the feldspar in some instances, and by the
bending and breaking of ottrelite prisms.

ORDER OF CRYSTALLIZATION.

We have then in this rock ottrelite, chlorite, feldspar and quartz, and
the three titanium-bearing minerals, ilmenite, rutile and anatase. What
is their genetic order of development? This is a difficult question to
answer without more data, and is particularly difficult in the cases of
the ottrelite and rutile. The relative position of the former mineral can
be determined easily, but the source of the solution introducing it is not
readily discovered. Ottrelite was formed alter the rock had undergone
metasomatic and dynamic changes that converted its clastic feldspar into

" \ii;it:is .ils l'ni\ ;iiicllmit;s|ir<p<liiUt vmi titunit iin Biotitamphibolgranit der Troas." N. J. B. i,
1883, pp. 187-193

ORDER OF CRYSTALLIZATION. 155

its resulting minerals, after its detrital quartz was sugared and the rock
had become a stable aggregation of minerals under the conditions of
environment then existing. This environment changing, owing to one
or more of the many factors affecting the character of a rock-mass, ot-
trelite was introduced probably, and it would seem necessarily, from
some extraneous source. The environment of the rock underwent a
third change, and this probably was an elevation, which strained the
albites, fissured the ottrelite and subjected the rock to normal surface
weathering, during which the conversion of ottrelite to chlorite was ini ■
tiated. Prior to the granulation of the clastic constituents the titanium
in some combination must have existed in the rock, but the mineralogic
nature of this combination is obscure. The most probable source of rutile
is from some titanium-bearing iron oxide, the presence of which has not
been made out definitely, except in the case of micaceous ilmenite, itself
manifestly of a secondaiy nature, occurring as it does in a clastic rock
and which yields no evidence of alteration. Ordinary granular ilmenite,
such as occurs so abundantly in phyllites, which is prone to decompo-
sition, was most likely the common source for all tbree minerals carry-
ing titanium, the rutile being an intermediate stage in the formation of
anatase. The micaceous ilmenite was developed before the formation of
the gneissic quartz, since the latter incloses it: the anatase probably
forming after the quartz, as it occurs in the interstices between the quartz
grains. If this be a correct interpretation, the order of crystallization
of the existing minerals is essentially as follows : First, rutile and mica-
ceous ilmenite, followed by the formation of gneissic quartz inclosing
them, and coincidently the growth of sericite inclosing rutile. The
glassy feldspars were next crystallized out, inclosing all the previously
formed minerals, and the anatase may have resulted as an alteration
product of rutile at about this stage in the rock's history. Then the
ottrelite began its growth, including all the other minerals in the rock;
and finally, the initial alteration of this mineral to chlorite closes the
rock's history, as far as the ottrelite-bearing phase is concerned, up to
the present time.

METAMORPHISM OF THE CLASTIC MATERIAL IN COXd LOME KATE PHASE.

Occurrence. — This conglomerate is stratigraphicallv equivalent to the
schist above described, and the phenomena mentioned below occur in
the rock from the town of Chittenden, between Chittenden village ('" Slab
City") and North Chittenden, where large outcrops occur along a divide
on the western side of the direct highway between these villages.

Character of the Rock. — The rock macroscopically is a well-marked con-
glomerate in which metamorphism is shown by the crushing of quartz

XXII I— lirix. Gkol. Soc. Am, Vol. 1. 1892.

156 C. L. WHITTLE METAMORPHIC CONGLOMERATE.

and feldspar grains and by the development of serecite, muscovite, biotite
and magnetite. These evidences of alteration are only incipient, so that
the genuine clastic character of its principal constituents is undoubted.
Quartz pebbles are most numerous and some attain dimensions suffi-
ciently large to be dignified by the term bowlders, being 18 inches in
maximum length, and make up nearly 90 per cent of the detrital material.
Gneiss and feldspar pebbles are also common, pebbles of the latter in
rare instances having dimensions of two by three inches. The ground-
mass is fine granular quartz, magnetite, plates of muscovite, and prisms
of sericite. Under the microscope the evidence of the clastic nature of
the rock is emphasized by the water-worn outlines of its pebbles and their
parallel arrangement due to gravity.

Secondary Enlargement of clastic Tourmalines. — Thin sections of the con-
glomerate (numbers 699 and 700) were studied in detail and their de-
scriptions are given later. The tourmalines occur in the rock as minute,
stout crystals, bounded by crystalline faces developed independently of
any apparent nucleus, and as imperfectly bounded areas of a secondary
origin deposited upon clastic nuclei of the same mineral. Figure 1,
plate 2, which is an instance of secondary enlargement of an original
clastic grain, is given to show development of prismatic planes, and also
two terminal faces of a rhombohedron imperfectly developed. The
boundary of this nucleus is not perceptibly water-worn, but in other ex-
amples of this phenomenon the nuclei are distinctly pebbles of attrition,
oriented with the other detrital constituents. The clastic tourmaline is
colorless in transmitted light when the plane of the polarizer coincides
with the extraordinary ray, and orange-yellow when the plane of the
polarizer coincides with the ordinary ray. It gives in converging light
one arm of a cross. The surrounding mineral is separated by a distinct
line from the core and is much darker-colored, as might be expected
from the isomorphous nature of the mineraL The pleochroism of the
rim is from brown to nearly black, and there are corresponding differ-
ences in the intensity of the interference colors ; the center polarizes in
brilliant greens and reds, while the interference color of the rim is masked
by the bod}'' color. The secondary tourmaline is perfectly oriented with
the core, and parallels the secondary enlargements of quartz grains de-
scribed by Irving and Van Hise* in this respect. There are abundant
inclusions' of iron oxide (possibby ilmenite) and some quartz in the sec-
ondary part, but the core is free from them. They are particularly
numerous about the sides of the angular core and along the basal por-
tion of the enlargement. Two corners of the latter have inclusions of
pale-green sericite prisms projecting into the groundmass, showing the

♦Bulletin No. 8, U. S. Geol. Survey, issi.

BULL. GEOL SOG. AM

VOL 4, 1692 PL 2

Figure 1.

Figure 2.

SECONDARY ENLARGEMENT OF CLASTIC TOURMALINE.

SECONDARY ENLARGEMENT OF TOURMALINES.

157

formation of tourmaline after the dynamic sericite, and also after the iron
products resulting from the decomposition of some iron-bearing silicate
or oxide. In ordinary light these prisms are seen to traverse the tour-
maline diagonally and they are certainly included. With a lens the
tourmaline can be seen to make the entire thickness of the section.

Another example of secondary enlargement has the allothegenic core
distinctly water-worn and oriented physically with the other elastics in
the section and optically with the authogenic addition (see figure 3).
The enlargement has nearly complete crystallographic boundaries — a
prism doubly terminated ; one end has the planes of a rhombohedron,

Figure 3. — Thin Section of water-worn tourmaline Pebble.

Showing secondary growth bounded by nearly complete crystallographic faces. (Drawing from
a microphotograph.)

the other having these and a small basal plane. In this the detrital
core is basal, giving a well-marked uniaxial cross of a negative character ;
it is of an orange-yellow color and free from interpositions. Owing to
its great depth of color, the enveloping tourmaline transmits light only
along its edges. Its crystal-faced outline is occasionally interrupted by
penetrating grains of quartz, and some grains may be entirely enclosed.
A third example shows the dark-colored, secondary mineral penetrat-
ing the clastic core nearly to its center along fissures formed prior to this
secondary growth. The contrast between the two parts is very distinct,

158 C. L. WHITTLE — METAMORPHIC CONGLOMERATE.

the center having a pule blue to pale orange color in transmitted light,
although composed of but one individual, and is free from inclusions,
while the outer part is very dark and thickly sprinkled with grains of
gneissic quartz.

►Still a fourth example (see plate 2, figure 2) has a dark core, with a still
darker rim, appearing as a network of bifurcating arms surrounding the
grains of the quartz and feldspar mosaic and on one side penetrating irreg-
ularly along cleavage lines into and enclosing parts of a clastic area of
plagioclase. Gaseous emanations or solutions carrying boracic acid are
well known to possess the power of attacking other minerals and produc-
ing new ones, and the action of the tourmaline-hearing agent, whatever it
may have been, seems to be another instance of the same phenomenon,
for the clastic plagioclase is attacked and the minute prisms of sericite
which had been developed in it along cleavage lines have been dissolved
by the growing mineral. Secondary glassy feldspars are included in the
tourmaline and reveal no evidence of having been attacked, but sericite
seems generally to have been absorbed. The clastic plagioclase is opti-
cally a unit with tourmaline ramifying through it ; hence the latter must
have eaten its way, excepting along cleavage lines, rather than to have
penetrated the feldspar along lines produced by its granulation under
pressure. Quartz does not seem to have been attacked, and one prism
of biotite has been built into the secondary mineral.

Numerous cracks traverse the core, most of which abut abruptly
against the authogenic part, and, although fissures and irregular cracks
may traverse the outer portion, they are usually limited to the ends of
the prism and do not traverse the core.

All the detrital tourmaline is macroscopically visible in the sections
studied ; nearly all are of an exceptional orange-yellow color, suggesting
a common source, and in size they vary from that of a pin-head up to an
eighth of an inch.

It has been difficult to ascertain the source of the material forming this
conglomerate horizon in Vermont, and it is hoped that a microscopic
study of the terranes below may result in the discovery of this tourma-
line in situ and furnish a basis for further evidence.

Two Periods of Disturbance indicated. — Two periods of dynamic action
are further indicated (see page 154) by the phenomena connected with
the tourmaline. Before the deposition of the allothegenic cores there
was a period of dynamic action, during which some of the detrital feld-
spar material was converted into an interlocking mass of quart/, biotite,
sericite and probably albite. Part of the quartz was comminuted, and
the fissures were produced in the tourmaline elastics. After this action
had ceased and the secondary tourmaline had been formed, a second

ALTERATION OF THE FELDSPARS. 150

crushing took place, much less intense than the first, indicated hy the
breaking and faulting of tourmaline prisms and the Assuring of the new
tourmaline mentione* I ab< >ve. This second crushing is probably to be cor-
related with that which broke the ottrelite prisms in the ottrelite schist.
Alteration of clastic Feldspars. — The alteration of detrital feldspars, prin-
cipally microcline, to quartz, sericite, biotite and albite is well shown.
This change takes place about the edges of the grains, along cleavage
planes emphasized by pressure, and along irregular cracks. Lines of in-
clusions in the clastic quartz serve to separate it from that resulting from
the alteration of feldspar, the latter being always clear and glassy. These
are commonly liquid-filled cavities with characteristic gyrating bubbles
of carbonate dioxide, but in both the clastic microcline and secondary
albite they are even more plentifully distributed. Liquid cavities in the
quartz may have, besides the bubble, a single prism of some indetermin-
able doubly refracting mineral or an apparent cube, which, however, is
also doubly refracting.

One of the thin sections (number 699) has a large pebble of microcline,
three-fourths of an inch long, which retains its original water-worn out-
line, excepting at its ends, where it is partially crushed. Lines of sericite,
biotite and quartz traverse it regularly along emphasized cleavage planes
and irregularly about grains resulting from granulation. Thousands of
minute dots of hematite or limonite are distributed through it, and there
is a tendency for them to be arranged in lines normal to the basal cleav-
age of the feldspar. It is these that give the flesh color to the mineral
in the hand specimen. Other interpositions are numerous rhombs of
siderite, exhibiting all stages between the pure mineral and its pseudo-
morphous resultant, limonite. These or their limonite representatives
occur throughout the rock, but they are noticeably more abundant in
the clastic feldspars. Their distribution indicates their formation after
the feldspar Avas deposited in the rock, and if this be the case, there Avere
two periods of alteration of the microcline — one during Avhich siderite or
some iron-bearing carbonate was a stable alteration product under the
conditions of environment, and a second during which the carbonate
itself changed to limonite, not contemporaneously Avith the development
of sericite, but posterior to that change and probably after the rock came
under the operation of surface disintegrating influences.

Sericite in minute hexagonal plates and prisms terminated by basal
planus are scattered through it and seem to have resulted from a direct
alteration of the feldspar without the aid of its introduction in solutions
from other parts of the rock. Liquid cavities are not nearly so numerous
as in the secondary feldspars.

The interdependence of the different phases assumed by minerals,

KiO

('. L. WIIITTLK

-MKTAMOKl'IIK' CONGLOMERATE.

upon all the varied factors going to make up their complex environment'
and the correlation of these phases oiler, it seems to me. one of the most
interesting fields of research to he found in the petrographic and chem-
ical history of a rock.

Clearing Action of growing Sericite. — Surrounding the pebble and along
lines traversing it, as well as about crystals of siderite, there are con-
formable zones of microcline free from inclusions of iron ] >r< (ducts. These
are associated with the development of siderite and sericite, and, wher-
ever lines of movement in the latter mineral traverse microcline or plagio-
clase pebbles carrying interpositions, on either side of them there are

r ' v •/■ '</ </ '• :/k y^v/*v >'•':■ </^,X'fX>^x X-\" V&v*-* •

SWiSSi

."X

■X

y

■X:^:*?

s&?*

:sf/VWvV

Figure 4. — r/iiw Section of microcline Pebble.
Showing clearing action of sericite. (Drawing from a microphotograph.)

parallel belts from which they have been removed. The border zone of
the pebble has its folia of sericite running parallel to it. As the sericite
grew as a product of dynamic metamorphism, it acted like a sponge,
removing the inclusions and forcing the iron into a new combination,
probably biotite. Figure 4 represents a triangular area of microcline
illustrating this. In the central part there is an area, a, carrying the
usual number of inclusions. Outside of this there is a zone, a', free from
iron inclusions: then there is a parallel line of sericite prisms,/*, outside
of which there is another parallel zone, c, also free from inclusions, and
this is surrounded by the mass of the pebble d. The correspondence of

ALTERATION OF THE FELDSPARS. 1G1

the optical orientation, even to the minutest twinned lamellae, is iden-
tical on either side of the line of sericite, and the feldspar appears very
fresh as compared with that not thus cleared of its inclusions. Its polari-
zation colors are much more uniform in the cleared areas, and the greater
the amount of the impurities and the more unequal their distribution,
the greater the variety of mottled, tinted colors under crossed nicols. In
case there are two lines of sericite close together, the interspace may he
entirely cleared (see a', figure 5).

In attempting to interpret correctly the cause of the outer clear rim
about feldspar pebbles only two hypotheses need be considered — it is
either secondarily deposited feldspar or is produced by some subsequent
action that eliminated the interpositions. If secondary, then the outlines
of the feldspar areas having inclusions are too jagged, and concave sur-
faces are too common to have been the result of ordinary attrition, while
the possibility that the new feldspar was added so as to change their out-
line to that of normal pebbles is very improbable. In the case of the
largest pebble in the section glassy feldspar accompanied by sericite
folia follows the outer part of the pebble for a distance, then penetrate
into the interior, following lines of sericite. Bordering areas of the back-
ground not containing sericite have no complementary clear zone in the
feldspar. Interior lines of sericite and their accompanying dependent
zones are only explainable in one way. To assume that they are sec-
ondary growths necessitates the subsequent displacement of the feldspar
clastic a distance equal to the cleared areas and a consequent probable
displacement of its optical continuity. As a matter of fact, all parts extin-
guish as a unit, the conformity of the positions of the twinning lamellae
on either side of the serecite indicating their original crystallographic
and optical continuity. Examples of apparent secondary enlargements
of clastic feldspar are becoming so commonly described that it may be
well in the future to bear in mind this phenomenon, which simulates so
closely that of genuine enlargement and which may have led to misin-
terpretations in the past.

Alteration of clastic Microcline into Plagloclase. — In connection with the
study of secondary feldspars in metamorphic rocks, it is interesting to
note the trend of certain phenomena observable in the granulated end
of this large pebble mentioned above where secondary albite and clastic
microcline are intermingled. Dr Wolff has lately called attention to a
possible relationship between detrital areas of feldspar and secondary
albites,* and the facts here observed substantiate his interrogative hy-
pothesis. With but very few exceptions in the Vermont rocks studied
by me have I noticed secondary feldspars free from inclusions of seri-

*Metamorphism of Clastic Feldspar in Conglomerate Schist: Bull. Mus. Comp. Zool., \<>l xvi,

no. id, p. ls:i.

162 C. L. WHITTLE METAMORPHIC CONGLOMERATE.

cite and quartz. These minerals may be distributed throughout the
feldspar, but there is a marked tendency for them to occur in groups
in the central part, and the outline of groups is rudely conformable to
that of the inclosing mineral. An explanation of this phenomenon has
never been offered that appears entirety satisfactory. It seems, however,
that we must be on the right track if we remember that the minerals,
quartz, sericite, biotite and plagioclase, are the commonly recognized
products of the decomposition of feldspar that has been subjected to the
influence of dynamic forces, while at the same time the presence of
quartz, sericite and albite making the groundmass of the rock would
be referred at once to such an origin by all who are familiar with the
ordinary microscopic phenomena observable in metamorphosed sedi-
•mentary rocks. Many feldspars (see those described below from East
Clarendon, Vermont) have interpositions of all other minerals occurring
in the rock, but the history of their immediate origin and growth is not
the same as for those under present consideration.

Figure 5 is taken from the granulated portion of the above-mentioned
feldspar and exhibits diagrammatically an area under the microscope
covered by a number 5 objective : a is a portion of the normal microcline
pebble filled with inclusions ; a1, the same, with its interpositions removed
by the development of dynamic sericite, i i and k h ; a2, areas of elastic
microcline included in secondary plagioclase, c ; and b are minute prisms
of serecite grouped in the plagioclases, but impinging against the micro-
cline on one side in the upper area.

At d are cleavage lines, emphasized by strain, showing abrupt disap-
pearance of inclusions along a line corresponding in direction to the basal
cleavage in the microcline h h and i i ; e, rhombs of limonite pseudo-
morphs after siderite; g, small liquid cavities arranged in lines parallel
to lines of hematite inclusions in the feldspar generally ; o, faint traces of
the double twinning of microcline occurring in the plagioclase. Two fad a
in particular are intended to be brought out : First, the grouping of seri-
cite prisms in the center of the lower plagioclase and their contact with
the clastic feldspar in the upper; second, the occurrence of isolated areas
of microcline in the plagioclase a2 and the conclusions to be drawn there-
from. The plagioclase is known to be secondary, as it occupies areas in
and includes portions of granulated microcline once continuous. Sericite
is developed along the lines h h and i /, which are cleavage partings.
The linear area of microcline, a2, which is isolated, is optically oriented
with a1 and has been separated from its parent along the basal cleavage.
Plagioclase surrounds and traverses it, dividing it into isolated areas, but
all oriented with one another. It seems to me that this is a case of pla-
gioclase forming about and from an area of microcline. The evidence in
favor of this is complete if all the data in the upper plagioclase are taken

ALTERATION OF THE FELDSPARS.

163

into consideration. The linear distribution of the microcline inclusion
and its optical relation with a are such that it manifestly was once a part
of the feldspar pebble. It is improbable that it could have been moved
in separate pieces from the line i i without having its crystallographic
and optic orientation disturbed. The twinning lamellae of the several
parts correspond with one another and with those in a\ while the ex-
tinction of c is not in parallelism with either set of twinned lamella? in
a2. The plagioclase c, resulting from the alteration of the microcline,

Figure 5.— Thin Section of microcline Pebble.
Showing alteration of elastic microcline to plagioclase.

ramifies through a2, apparently absorbing it, and at the same time caus-
ing the development of sericite about and in it. This will be alluded to
again when the areas of sericite b are considered. The arrangement of
the fluid cavities g1 in lines parallel to the lines of hematite inclusions
in the microcline does not seem to be accidental, but seems rather to in-
dicate the operation of a grinding influence of the inclusions as the new
feldspar formed and absorbed the old. Cleavage lines d, which are par-
allel to i i, also seem to be connected in some way with the cleavage in

XXIV— Bum. Ueol. Soc. Am., Vol. 4, 1892.

164 C. L. WHITTLE — METAMORPHIC CONGLOMERATE.

the pebble, as though the plagioclase, as it replaced the microcline, took
on a crystallographic position, controlled by old planes in the latter that
had been emphasized by dynamic movements, in which one cleavage is
parallel to P or M in the microcline. Along these cleavage lines, at o,
there are faint indications of twinning, after the albite and pericline laws.
Plagioclase may have replaced old microcline twinning lamellae, itself
twinning after the same law, so that we may have the original twinning
of the microcline handed down to its alteration product, plagioclase. The
upper group of sericite inclusions, b, stops short in a plane against these
cleavage lines, extends across the plagioclase to the left, and impinges
against the microcline, which at this point is not crushed or strained,
while the feldspar on all other sides of the upper area is granulated.
Does not the area defined by these inclusions represent original micro-
cline, now replaced by plagioclase, the k going into the sericite?

So complex have been the conditions of environment that it is very
difficult to interpret correctly, if at all, many phenomena exhibited in
metamorphosed rocks, but in this case it seems to be legitimate to sup-
pose that for a time the conditions were such that, as the plagioclase
formed from the microcline, sericite was developed. Afterwards the intro-
duction of new factors began. Sericite was no longer developed, while
plagioclase continued to form both from the microcline and by addition
from other parts of the rock, the growth taking place in all directions ex-
cepting where the area of inclusions abuts against the microcline which
had escaped granulation. Where this growth took place uniformly in
all directions the inclusions are seen to occupy a central group in the
plagioclase as in the lower area. The linear area of microcline, cr, with
its associated sericite prisms, is an intermediate stage between original
clastic feldspar and the completed change b.
' In this connection Dr Wolff remarks :

" It does not seem possible to explain all these cases of mere outward growth of
the feldspar grains by addition of fresh feldspar of the same species to the core, but
rather by an actual replacement of the detrital core by the feldspar of the enlarge-
ment."*

Strongly contrasted as to immediate origin are the secondary feldspars
found in another phase of this conglomerate horizon and those occurring
in a phyllite in Massachusetts.

CHLORITE SCHIST AND PHYLLITE.

Their Plications built into secondary AlbiteS. — The differences in the envi-
ronment of growing secondary feldspars and their consequent histories
are seen when the above case is compared witli the porphyritic feldspars

* Metamorphism of Clastic Feldspar in Conglomerate Schist: Bull. Mus. Com p. Zool., vol. xvi,
no. 10, p. 182.

CHLORITE SCHIST AND PHYLITE GROUNDMASS. 165

occurring in the chlorite schist found at East Clarendon, Vermont, and
the phyllites of Greylock mountain, situated southwest of North Adams,
Massachusetts. In the occurrence at the first-named locality the feldspar
(albite), which occurs as single individuals or simple twins, a fourth of an
inch across, was formed after the rock had been metamorphosed from an
original shale to a chlorite schist and mountain-making forces had rear-
ranged the minerals composing the rock into minute crenulations.

Composition of the Ground/mass. — The groundmass of the schist is com-
posed of granular, gneissic quartz and feldspar, much sericite and chlorite
marking its foliation, as essential constituents, and as accidental minerals
there are innumerable rutile dots and prisms, prisms of tourmaline and
little black plates, probably ilmenite. All these, including the minute
plications of the schist, have been built into the albite as it grew. Quartz
droplets are arranged in sharp serratures, the continuation of the corru-
gated lines outside the crystals; but the sericite and chlorite, particu-
larly the former mineral, seem to have been eliminated by the growing
albite forcing them to one side or by the chemical solution which de-
posited the feldspar attacking and dissolving them. The chlorite is
occasionally included; the sericite rarely. Rutile, ilmenite and tour-
maline are also enclosed. In detail the outlines of the crystals are very
jagged, the feldspar projecting in tongues into the background along the
schistosity; but, considered as a whole, they are well-defined prisms.
The colorless inclusions are by no means limited to quartz, for many give
imperfect hyperboke and are secondary feldspars of a younger genera-
tion. Nothing now remains in the rock that can be said to be of clastic
origin, and certainly after the rock had been converted into a chlorite
schist and crenulated, as we find it to-day, no detrital feldspar could have
been left to serve as nuclei or furnish material for the large, last-formed
porphyritic albites. Solutions with the necessary elements must have
been derived from some extraneous source.

The occurrence of the albites in the Greylock phyllites collected by
Dale and described by Wolff* have much the same history, only
secondary albites there have been enlarged by a tertiary growth of the
same mineral.

The Assuring and occasional faulting of the large albites from East
Clarendon is to be correlated with the faulting of the secondary tour-
malines and ottrelite prisms above described and indicate a second
period of mountain-building forces.

My thanks are due to Dr Wolff, who has given me many valuable
suggestions during the preparation of this paper.

*Ibid., p. 183.

Cambridge, Mass., March, 1892.

Explanation of Plate 2.

Secondary Enlargement of clastic Tourmaline.

Figure 1.— Secondary enlargement of elastic tourmaline pebble, showing prismatic
planes and slight development of terminal planes. Partially included
sericite prisms and occasional inclusions of quartz grains in new
growth.

Figure 2. — Secondary enlargement of clastic tourmaline. The core is free from
interpositions ; the secondary mineral has abundant inclusions of
gneissic quartz aud feldspar. Many of the fissures of the core abut
abruptly against the new mineral, snowing two periods of straining.
The growing tourmaline is seen to have attacked a clastic area of
plagioclase, penetrating it irregularly and absorbing sericite previously
developed along cleavage lines.

(106)

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA
Vol. 4, pp. 167-178, pl. 3 February 27, 1893

PHASES IN THE METAMORPHISM OF THE SCHISTS OF
SOUTHERN BERKSHIRE*

BY WILLIAM H. HOBBS

{Read before the Society August 16, 1892)
CONTENTS

Page

Introduction 167

Beds represented within the Area 167

Evidences of orographic Disturbances 168

Porphyritic Minerals of the Schists resulting from metamorphic Action 169

The Minerals and their Association 169

Porphyritic Feldspar 169

Granophyre Structure in Feldspar 170

Its Origin 171

Secondary Enlargements of Feldspar 171

Their Origin 173

Garnet and its secondary Enlargements 173

Staurolite 174

Reactionary Rims of Staurolite and Magnetite about Garnet 174

Tourmaline and its secondary Enlargement 175

Porphyritic Biotite 176

Ottrelite. 176

Summary and Conclusions 177

Introduction.

Beds represented within the Area. — In southwestern Berkshire county,
Massachusetts, and in northwestern Litchfield county, Connecticut, is an
area in which non-calcareous schistose rocks alternate with limestones
which are in part micaceous, dolomitic, graphitic, pyroxenic, tremolitic
or quartzitic.f Though the schists are the "mountain rock," they are
found in the valleys as well and are frequently inclosed as islands in

* Published with the permission of the Director of the United States Geological Survey.

fThe area has been described and mapped by Professor J. D. Dana : On Taconic Rocks and Strat-
igraphy, with a Geological Map of the Taconic Region. Am. Jour. Sci., 3d ser., vol. xxix, pp. '205-
■i-ii, pp. 4;;7-M3, pl. ii.

XXV— Bum,. Geol. Soc. Am., Vol. 4, 1892. (167)

168 W. H. HOBBS METAMORBHISM OF BERKSHIRE SCHISTS.

the limestone. The rocks here described occur in portions of the town-
ships of Egremont, Sheffield and Mount Washington, in Massachusetts,
and of Canaan and Salisbury, in Connecticut. They have been studied
areally and structurally in the field and petrographically in the labora-
tory. The full report of the investigation will appear elsewhere.*

The area includes three beds of schist separated by beds of limestone,
besides the thin layers of the former which are sometimes found within
the limestones near the contact. The lowest of these schist beds is asso-
ciated with quartzite and gneiss, and is more lacking in uniformity of
character than the others. It incloses numerous veins of coarse pegma-
tite and is specially rich in tourmaline, though this mineral is also found
in the two other horizons.

The next younger schist is separated from the one just mentioned by
a dolomite, which is always very crystalline, and at many localities con-
tains white pyroxene, tremolite or phlogopite. It moreover contains
layers of graphitic rock and of canaanite.f The schist horizon itself is
quite variable in character, but is frequently distinguished by the occur-
rence of macroscopic garnets and staurolite.

The upper schist bed is separated from the last mentioned by a lime-
stone in which neither sahlite, tremolite nor canaanite has been found.
The schist itself is free from the macroscopic garnets and staurolite
characteristic of the central bed. In common with both the other beds
it contains porphyrinic crystals of feldspar, but here they seem more
generally to have glistening cleavage surfaces. Especially in the Mount
Washington area this bed shows facies that are quite sericitic or chloritic,
the latter with magnetite often in octahedra as big as a pea. Ottre-
lite, though not restricted to this horizon, is more frequently found here
than in either of the others. Though the rocks of the three non-calcare-
ous beds have a preponderance of feldspar, they are structurally schists
and they are so designated, as it is convenient to distinguish them from
typical gneisses in adjacent territory. Notwithstanding characteristic
differences can be pointed out, serving to distinguish the three beds when
regarded as units, individual hand specimens from each often show re-
semblances more striking, so that it is generally impossible to refer a
specimen to a definite bed on the basis of petrographic character only.

Evidences of orographic Disturbances. — Typically metamorphie minerals
abound in all beds, but especially in the central schist bed and the dolo-
mite underlying it. The beds have been thrown into sharp folds, most
frequently reversed, with resulting shear planes and secondary foliation
at many localities.

*The work here referred to forms part of an investigation conducted by Professor Raphael
Pumpelly for the United States Geological Survey,
t American Geologist, vol. xv, 1892, p. 45.

porphyritic constituents of the schists. 169

Porphyritic Minerals of the Schists resulting from metamorphic

Action.

The Minerals and their Association. — It is my object in this paper espe-
cially to describe the so-called porphyritic constituents of the schists that
have been developed or modified by metamorphic agencies. Under this
head are included feldspar (largely an acid plagioclase), garnet, stauro-
lite, tourmaline, biotite and ottrelite. Other Constituents present in
greater or less quantity are sericite. quartz, graphite, chlorite, magnetite,
ilmenite, pyrite, nbrolite, calcite, rutile. sphene (and leucoxene), zircon
and apatite. In nearly all specimens there is a matrix made up of vary-
ing amounts of feldspar, quartz and a micaceous mineral, which is in
some cases a silvery mica (sericite) ; in other instances sericite with bio-
tite or chlorite. Associated with these minerals are accessory graphite,
ore material, etc. Almost without exception porphyritic feldspars occur
in the matrix, usually many times larger than the feldspar grains com-
posing it.* In addition to the modifications of the rock arising from the
micaceous constituents present, petrographic variations consist mainly in
the character of the porphyritic feldspar and in the presence or absence
of the other porphyritic constituents, viz: garnet, staurolite, tourmaline,
biotite and ottrelite. The central schist bed has furnished most of the
specimens in which the structures I shall describe were observed, though
such structures do not seem in all cases to be restricted to that bed.

Porphyritic Feldspar. — The porphyritic feldspars appear under a num-
ber of modifications. In certain facies of the rock they are more or less
oval in shape and inclose with more or less uniformity blades of seri-
cite, particles of graphite, ore material or tourmaline. They are com-
monly either simple individuals or simple twins. They quite resemble in
sections the beautiful photomicrograph which is figure 8 of the paper
by AVolff on "The Metamorphism of Clastic Feldspar in Conglomerate
Schist." f Though these feldspars may show no marked evidences of
strain, many instances of polysynthetic twinning have been observed, and
the occasional localization of the lamella? about cracks in the individual
would indicate that the twinning is the result of internal mechanical
movement. The twin lamella1 allow of the determination of the feldspar
as an acid plagioclase.

Dynamic metamorphism lias at other localities been more intense, as
evidenced in sections where the granulation of the feldspars may be

* See descriptions of similar feldspars in the schistose and conglomeratic rocks of lloosao moun-
tain and elsewhere. (Pumpelly: The Relation of Secular Rock-Disintegration to Certain Transi-
tional Crystalline Schists. Bull. Geol. Soc. Am., vol. ii, 1891, pp 209-224. Wolff: Metamorphism of
Clastic Feldspar in Conglomerate Schist. Bull. Mus. Comp. Zool., vol. xvi,1891, pp. 173-183, pis. i-ii.)

t Bull. Mus. Comp. Zool., vol. xvi, 1891, pp. 173-183, pis. i-ii.

170

W. H. HOBBS — METAMORPIIISM OF BERKSHIRE SCHISTS.

seen. This may be largely peripheral, as in a specimen (number 3230) *
from near Ore Hill, or it may include nearly the entire crystal, as in a
number of thin sections (number 3224) from Miles mountain. Such
pronounced granulation seems, however, to be most developed in the
vicinity of shear planes, and is accompanied by a stretching and tearing
of the other constituents. Figure 1, A shows the effect of this action on
two adjacent garnets (number 3230).

Granophyre Structure m Feldspar. — Those structures which 1 desire here
more especially to emphasize, however, seem to be found farther removed
from shear planes, and concern phases of metamorphism where mechan-
ical movement has been a minimum. In such localities the feldspars
have frequently a mottled appearance, like D in figure 1 (numbers 3111,
3326, 3328, 3463).

__s

<o=>

C-

Figure 1.— Examples of Deformation and modified Growths of Minerals in Schists.

A = stretched garnets. B = secondary growth of tourmaline ; the oval core has brown tones,
the enlargement blue or plum tones; the cloud}7 material near the junction is probably graphite.
C= zonal structure in tourmaline. D = mottled feldspar. E = parallel growth of ilmenite and
chlorite.

The included areas sometimes take the form of curving canals, at
others polygonal outlines, and, in short, exhibit all the peculiarities of
the micropegmatite or granophyre structure. Hexagonal outlines char-
acterize many of the areas, and there can be little doubt that they are in
these cases quartz (number 3463).

The inclosed quartz extinguishes alike over considerable areas, but
sometimes shows several orientations within a single crystal of feldspar .f
The feldspars which show this structure exhibit in many cases the min-
imum of crushing and but little effect of stress, while in other cases the
granophyre structure coexists with a pronounced granulation and exhi-
bition of secondary twinning. In the latter ease the structure is very
complicated, and it is difficult to distinguish the secondary quartz from
the mosaic of feldspar, it was frequently observed (in those cases where
but little deformation could be made out) that the granophyre occupies
the center of a crystal, leaving a clear rim.

*The numbers of sections are those of the Uniti'.l States Geological Survey collection.
•f-Cf. Iddings, Obsidian Cliff, Yellowstone National Turk . Seventh Ann. Rep. V. 8. God Sur., 1888,
p. 275, plate xv, fig. 5.

ORIGIN OF THE GRANOPHYRE STRUCTURE. 171

Its Origin. — The question of the origin of the granophyre in these doubt-
less clastic rocks is a difficult one. It is a question that deserves further
study, and I hope later to be able to throw a little more light on the
problem. For the present it can be said that the relation of the inter-
grown quartz to the quartz outside, as exhibited in a number of sections
lends no support to the view that the granophyre structure has been pre-
served from some detrital grains which have an igneous origin, but that
it is of a secondary nature, being developed in the already formed rock.
The usual interpretation of granophyre structure to indicate an igneous
origin for the rock in which it occurs is no longer tenable. Irving in
1883* described micropegmatite in a number of granitic porphyries
and augite syenites from Lake Superior, the secondary nature of which
was evident from its quartz being oriented like the areas of secondary
quartz lying without the feldspars. Sornewhat similar cases have been
described by Judd.f In a recent memoir by Julius Romberg^ on the
petrographic characters of an extensive series of Argentine granites the
granophyric structures are described in much detail with the aid of beau-
tiful plates. The author raises the question of their secondary origin
through weathering, and adduces many facts which make it probable
that this is their origin.

In some of the feldspars which show the mottled structure in the
rocks now under consideration it can be determined that the inclosed
areas are feldspar of a somewhat different composition (microperthite
structure). This is particularly well shown in the instance of a feldspar
core having a rim which polarizes yellow, the core polarizing gray. A
set of fhottlings in the core give the same yellow tint as the rim and
extinguish with it. This would seem to show that the original feldspar
core had been partially replaced by a feldspar of different composition,
which composes the rim entire. This view is quite in harmony with
Wolff's deductions concerning the feldspars in the conglomerate schist
of Hoosac mountain.||

Secondary Enlargements of Feldspar. — Secondary enlargements of feld-
spar seem to be quite common in the rocks under investigation, and they
have been found at localities widely separated. § Occasionally these en-

*The Copper-bearing Rocks of Lake Superior: Monograph V, U. S. Geol. Survey, 1883, p. 114,
plates xiv, xv.

f On the Growth of Crystals in Igneous Rocks after their Consolidation : Quart. Journ. Geol. Soc.
vol. xlv, 1889, pp. 175-18G. pi. vii. Ibid., vol. xlii, 1886, p. 72.

X Romberg, Petrographische Untersuchungen an argentinisehen Graniten,.mit besonderer Be-
rucksichtigung ihrer Structur und der Entstehung derselben : Neues Jahrbuch f. Mineralogie,
etc., Beilage-Band viii, 1892, pp. 314-323, 374-378, plates ix-xii.

!| Loe. cit. See also Lehmann, Jahresbericht der Schlesischen Gesellschaft fi'ir Vaterlandische
Cultur, 1880, pp. 119-120.

<j Thorpe mountain (numbers 3574, 347G ana 3477); northeastern slope of Mount Washington,
(number 2129) ; southeastern slope of Mount Washington (number 3104 ) ; Miles mountain (number
3213£), ami near Rattlesnake hill (number 3030).

172

W. H. HOBBS METAMORPHISM OF BERKSHIRE SCHISTS.

largements are visible under a lens, OAving to the unequal distribution of
graphite (number 3574). The commonest case of enlargement is that in
which there is but one secondary growth visible (figure 2, B, C, D). The
original growth shows crystal boundaries and is sharply outlined against
the enlargement, which has generally an irregular boundary and con-
tains more sericite, interpositions of ore, etc. The enlargement is gen-
erally at least of a more basic feldspar than the core, as shown by the
extinction angles. In the growths figured, B is evidently cut near the
brachypinacoid and 0 probably near the base, as in this latter instance
the extinction angles are nearly the same and closely parallel to the
long side. It is thus probable that both feldspars are intermediate in
composition between oligoclase and andesine. In D is represented an
unusual growth, of which the core is simply twinned, though the enlarge-
ment is not (see plate 3, figure 2, A). In the same section is another
growth in which core and rim are twinned alike. I have noticed some-

A h C if

Figure 2.— Secondary Enlargements of Plagioclase.

A, B, Cand D are examples of secondary enlargements of plagioelase which occur in the schist
of Mount Washington, near Joyceville (number 3104). / is the core in each case; //atod ///are
the enlargements. .4 = rounded mottled core with two enlargements; B C= examples of core
with crystal boundaries; D = unusual instance of twinned core surrounded by an untwinned en-
largement.

what analogous cases in the growths of epidote around allanite from the
porphyritic granite of Ilchester, Maryland* the core of allanite being
twinned, though the encircling oriented epidote is a single individual.
In the gneiss of Warner mountain, east of Sheffield, Massachusetts, such
growths occur, and here the epidote has been observed twinned like the
allanite in one instance, and in another the allanite core is twinned and
the epidote untwinned. Van Hise f has figured a grain of feldspar with
ah enlargement, and both are twinned alike. Wolff states that in the
enlarged feldspars of the conglomerate schists of Hoosac and Hear moun-
tains, twins are sometimes common to both core and rim, but also are
found only in the core.J Judd || describes and figures an enlargement of

* Am. Journ. Sci., 3d ser„ vol. xxxviii 1889, pp. 223-228, figs. 1 and 2.

fBull. no. 8, II. S. Geol. Survey, pt. ii; also Am. Journ. S.-i. 3d ser., vol. xxvii, L884, p. 399.

JLoc. cit., p. 182.

HQuart. Journ. Geol. Soc, xlv, p. 186, pi. vii, figs. I and 2.

SECONDARY ENLARGEMENT OF MINERALS. 173

feldspar in the " labradorite andesite " of the isle of Mull, in which the
twins of the core are prolonged as twins in a more acid feldspar.

An enlargement where the core is unmottled but has a rounded outline
is seen at A of figure 1, plate 1. In figure 2, A, there is exhibited a some-
what different modification. In this instance, as in some others, the core
is mottled and of irregular outline. Two enlargements are indicated by
the different extinction angles (Cf. also plate 1, figure 1, B). Second en-
largements have been found also at other localities (numbers 3218 2 and
3115). In a specimen from near Jug End, Mount Washington (number
3139) there seem to be several zones of growth in feldspar.*

Their Origin. — The fact that the cores of many of the growths which
have been described have crystal boundaries makes it extremely improb-
able that they can be of detrital origin, though the rocks themselves are
undoubtedly clastic. The most probable view of their origin, it seems to
me, would regard them as a metamorphic product due to the recrystalli-
zation of the detrital grains of the rock, as in the better-known cases of
garnet and staurolite.f

Garnet and its secondary Enlargements. — As already stated, this mineral
when in macroscopic crystals is specially characteristic of the central
schist bed. It is the common dark red, nearly opaque variety, and
occurs in rhombic dodecahedra with truncations by the icosatetrahedron.
The crystals vary in size from those that are microscopic to those a centi-
meter or two in diameter. Frequently, though not always, they are
associated with staurolite. They exhibit the usual characters on micro-
scopic examination. They have a decided pink absorption and are some-
times compact, though often ragged in appearance from the inclosure of
the constituents of the matrix. Minute hair-like interpositions, which
are very abundant, are with much probability rutile. In the schist of
Johnny's mountain, near Sheffield (number 3114) interesting secondary
enlargements of the garnet have been observed. The core or first growth
is pink and comparatively free from inclusions, with the exception of the
hair-like interpositions above referred to. The rim of secondary enlarge-
ment, making from one-half to two-thirds the area of the entire growth,
is nearly colorless, and near its junction with the core is filled with an
aggregation of cloudy ore material, probably magnetite. Where several
crystals have formed in a continuous aggregate, the enlargement incloses
the aggregate, just as in other cases it incloses an individual (figure 3, A).

*Cf. Judd, loe. cit., plate vii, fig. 3.

fFor the literature of secondary feldspar enlargements in rocks of eruptive origin see : —
Haworth, A Contribution to the Archean Geology of Missouri ; Inaug. Dissertation, Johns Hop-
kins University; also printed in American (ieologist, May and June, 1888.
Judd. Quart. Journ. Geol. Soc. xlv, 1889, pp. 175-18G.
Romberg, Neues Jahrbuch fur Mineralogie, etc., Beilage-Band viii, L89?, p. 304, plate \v, fig. 54.

174

W. II. IIOP.BS — METAMORPIIISM OF BERKSHIRE SCHISTS.

In one instance stains of iron oxide were observed to traverse the enlarge-
ment and stop abruptly at its junctions with the core (figure 3,5).

Staurolite. — This mineral has only been found in the central schist bed.
It is usually macroscopic and its crystals sometimes attain to a length
of two or three centimeters. They are bounded by the usual forms, and
are frequently twinned in inclined crosses. The color is usually black,
but is sometimes cinnamon-brown. Under the microscope the mineral
presents the usual characters with strong pleochroism. like the garnet,
it is sometimes compact, sometimes very ragged, from inclosures of the
matrix. Secondary enlargements have not been determined, but the
observation of crystals with an outer zone which, unlike the center, is
free from inclusions, makes their occurrence not improbable.

Figure 3.— Garnets with secondary Enlargements.
From schist of Johnny's mountain, near Sheffield.

Reactionary Rims of Staurolite and Magnetite about Garnet. — The arrange-
ment of staurolite and garnet is in some instances such as to show that
the staurolite is a later development. Its crystals seem sometimes to be
developed about and near garnets, as in the rock from the Lion's Head,
northwest of Salisbury (number 3431). In the schists of the north end
of the ridge called June mountain (northeast of Sheffield village), a crown
of staurolite prisms almost encircles an individual of garnet (number
3306 B). The garnet is pink, and is filled with microlites (rutile). Be-
tween the encircling crown of roughly radial staurolite crystals and the
garnet individual is considerable magnetite (see figure 4). The fact that
staurolite has not been found except with garnet, though garnet is found
unaccompanied by staurolite, taken in connection with the statements
just made, shows that staurolite has generally been a later development
in the rock, and probably requires more intense metamorphism. In
some instances, at least, it is indebted to the garnet for its iron and
probably also much of its alumina and silica. In the ease of the crown
about garnet, we seem to have a true reactionary rim, where the iron of

SECONDARY ENLARGEMENT OF TOURMALINE.

175

the garnet has been sufficient to supply the staurolite and leave a resi-
due, which appears as magnetite.

Tourmaline and its secondary Enlargement. — This mineral is specially
abundant in the lowest schist bed, occurs usually in black prisms, and
in size varies from microscopic dimensions to several centimeters. In
the pegmatite veins it is often found in knots as large as one's fist, in-
closed in quartz. It is less abundant in both the other horizons, but
appears not infrequently in crystals, which are just discernible under
the lens. Under the microscope the only noteworthy characters of this
tourmaline are the absorption and a marked zonal structure without per-

Figure 4. — Portion of a Crown of Staurolite and Magnetite encircling a garnet Individual.

In ordinary light. X 33.

ceptible gradations in color. There are nearly always a core and an en-
circling rim. The core has usually pleochroism in blue to plum tones,
whereas the rim shows brown tones like biotite. Sometimes the outline of
the core is parallel to the bounding planes (figure 1,0). In the graphitic
mica schist of the second railroad cut west of Ore Hill (number 3534)
undeniable enlargements of tourmaline are found. One of these is rep-
resented in figure 1, B. The core is oval, and is surrounded by a halo
of cloudy opaque material (graphite). It shows the brown tones like
biotite. About this rounded and probably detrital core a stoutly colum-

XXVI— Bull. Gkol. Soc. Am., Vol 4, 1802.

176 W. H. HOBBS METAMOKl'IIISM OF BERKSHIRE SCHISTS.

nar crystal of tourmaline has been formed and oriented like the core.
The dichroism of the enlargement is unlike the core, as it shows plum
tones approaching purple. Secondary enlargements of tourmaline have
been observed simultaneously by Whittle in the Green mountains and
are described elsewhere* in this volume.

Porphyritic Biotite. — This mineral quite frequently appears in por-
phyritic blades, generally across the lamination. These are sometimes
several millimeters in diameter, and in the rock in which they occur are
several times larger than the sericite and biotite of the matrix. Small
sericite blades are generally inclosed in this porphyritic biotite.

Ottrelite. — Ottrelite is found in the Mount Washington area, where its
minute disks occasionally spangle the surface of the schist. Under the
microscope the basal sections appear irregular and somewhat opaque.
Prismatic sections are lath-shaped and are sometimes broken across. They
show twins both simple and polysynthetic according to the Tschermak
law. The index of refraction is higher than that of chlorite, and extinc-
tion angles were measured as high as 17 degrees. The absorption is in
blue, green and yellow tones. The double refraction is feeble, causing
low gray interference colors. It is often difficult to distinguish this min-
eral from chlorite, which general^ accompanies it. Growths of ilmenite
similar to those described by Wolff in the New England schists f are not
uncommon, but they are here apparently of chlorite, possibly an alter-
ation product of ottrelite. Whittle X has shown that the ottrelite in
rocks from the Green mountains is altered extensively to chlorite. The
development of ottrelite in the Salmien superieur has been made the
subject of an extended memoir by Prof. J. Gosselet,|| of Lille. This
memoir is important because it throws a great deal of light on the mode
of development of other porphyritic constituents of metamorphic schists.
M. Gosselet concludes (p. 202) that the ottrelite was formed after the rock
was in the condition of a schist or phyllite, since all the constituents of
the schist are included in it. Further, the vicinity of the ottrelite crys-
tals shows an impoverishment of quartz. There has also been a local
movement of the particles around the ottrelite crystals at the time of
their development. The larger grains of hematite and ilmenite have
been forced out from the positions occupied by the ottrelite and concen-
trated in a zone around it. The diversion of the trains of inclusions in
the rock as they enter the ottrelite crystal, and the bending of mica scabs,

*Ante, p. 152.

t On some Occurrences of < >ttrelite and [lraenite Schist in New England : Bull. Mus. Comp. Zoo).,
vol. xvi, 1890, pp. 159-165.

I An < ittrelite-bearing Phase of a Metamorphic Conglomerate in the Green Mountains : Am. Jour.
Sci., 3d sci-., vol. xliv, 1892, pp. 274-275.

|1 Etude* sur l'origine de l'Ottrelite, ire Etude, I'Ottrelite dans 1'' Salmien superieur: Ann. Sor.
Geol. Nord, Lille, vol. xv, L888, pp. L85-318.

SUMMARY AND CONCLUSIONS. 177

show that a general movement occurred in the rock subsequent to the
formation of the ottrelite, tending to bring the ottrelite crystals parallel to
the schistosity. Professor Gosselet ascribes the development of the ottre-
lite to heat, of which the cause is unknown* The spaces left behind the
mineral by its movement become filled either at the time or subsequently
by muscovite, quartz and oxide of iron, giving rise to peculiar tufts going-
out from the mineral. Besides the crystals of ottrelite, M. Gosselet de-
scribes with great care in the same rocks somewhat irregular rounded
areas (noyaux) of cloudy, in part doubly refracting, material, surrounded
by one or more zones, differing in some respects from the core, which he
believes to be the remains of more elementary forms of ottrelite rather
than crystals — globulites.

Summary and Conclusions.

From the foregoing, it may be asserted with much probability that the
minerals of a porphyritic nature which occur in the schists, viz., feldspar,
garnet, staurolite, tourmaline, biotite and ottrelite, were developed in
originally clastic rocks as a result of the orographic disturbances to which
they have been subjected. Internal mechanical movement seems to have
played only a subordinate role in their formation, as shearing brings
about a crushing and tearing of the constituents not generally observable
in the sections. The development of the porphyritic constituents seems
therefore to be due to a partial recrystallization of the rock as a result of
what I would call static metamorphism — i. e., metamorphism in which
pressure is the important factor, in contrast to internal movement, though
heat and a mineralizer were important adjuncts. The universal dis-
tribution of the porphyritic feldspars might indicate that they require
a less intense metamorphism for their development than do garnet and
staurolite, and this is probably true, though it cannot be asserted that
some of these feldspars are not detrital grains like a portion of those de-
scribed by Wolff.f Evidence has been given to show that the garnet
developed largely before the staurolite, and that the latter probably re-
quires for its formation more intense metamorphic action. The stauro-
lite crystals have been developed, at some expense to the garnet, for iron,
and probably also alumina and silica. This is shown by the crown of
staurolite crystals about garnet in the June mountain schist. This fact,
taken in connection with the secondary enlargements of feldspar, garnet,
and tourmaline, and the probability of enlargements in the case of stauro-
lite, indicates that the metamorphism which these schists have suffered

*" La formation de Pottrelite est du a une production de chaleur dont il faudra chercher la
cause." Loc. cit., p. 203.
fBulI. Mus. Comp. Zool., vol. xvi, 1891, p. 17.">.

178 W. II. HOBBS — METAMORPHISM OF BERKSHIRE SCHISTS.

was not a continuous process, but occurred in stages, of which there must
have been several. It was in one of the later of these stages that the
staurolite was developed.

The importance of the enlargement of mineral fragments in clastic
rocks as a factor in their alteration by metamorphism, has been empha-
sized by Irving and Van Hise in their papers on the rocks of the Lake
Superior region. This study presents a somewhat different phase of the
subject and adds an instance of their occurrence in rocks which have
been more profoundly metamorphosed. The investigation here outlined
is not completed. The interesting problems of the chemical nature of
the reactions involved in the development of the feldspars and their
secondary enlargements, and of the other porphyritic constituents, will
require for its solution a separation and chemical examination of the dif-
ferent constituents.

In conclusion, I would acknowledge my indebtedness to Dr G. H.
Williams and Dr J. E. Wolff for valuable suggestions and criticism.

Explanation of Plate.

Sections of garnetiferous porphyritie Schist from the southeast Slope of Mount Washington,

showing secondary Growths of Feldspar.

Locality (number 3104) on road between Joyceville and Plantain Pond.

Figure 1. — A = Secondary growth of feldspar, of which the core has a rounded

outline.
B = Feldspar growth with two distinct enlargements indicated by

different extinction angles. The core has a micropegmatite structure.

Crossed nicols. X 77.
Figure 2. — A = Simply twinned feldspar core with an untwinned enlargement.

Crossed nicols. X 48.

BULL. GEOL. SOC. AM.

VOL 4, 1892. PL. 3.

SECTIONS OF GARNETIFEROUS PORPHYRITIC SCHIST.

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA
Vol. 4, pp. 179-190 February 27, 1893

CONTINENTAL PROBLEMS

Annual Address by the President, G. K. Gilbert

(Read before the Society December 30, 1892)

CONTENTS

Page

Introduction 179

Differentiation of continental and oceanic Plateaus 180

Rigidity versus Isostasy 182

Nature of density Differences 183

What caused the continental Plateau? 183

Why do continental Areas rise and fall? 186

Are Continents permanent? 187

Do Continents grow ? 187

Summary 190

Introduction. — For a decade attention has been turned to the continents.
Through the distribution of animals and plants Wallace has studied the
history of the former connection and disconnection of land areas. Theo-
ries of interchange of land and water have been propounded by Suess
and Blytt. By means of geodetic data Helmert has discussed the broad
relations of the geoid to the theoretic spheroid. Darwin has computed
the strength of terrestrial material necessary to sustain the continental
domes. James Geikie, treating nominally of coast lines, has considered
the shifting relations of land and sea, and a half score of able writera
have debated the question of continental permanence. The American
Society of Naturalists, now holding its annual meeting at Princeton, N. J.,
devoted yesterday's session to the consideration of such evidences of
change in the geography of the American continent as are contained in
the distribution of animals and plants. The intercontinental congresses
auxiliary to the World's Fair next summer are to be devoted to the dis-
cussion of continental and intercontinental themes ; and a committee, at
the head of which stands one of our vice-presidents, invites the geologists
of the world to assemble for the consideration of those broader questions
of earth structure and earth history which affect more than one hemi-

XXVII— Bull. Gkol. Soc. Am., Vol. 4, 1892. (179)

180

G. K. GILBERT — CONTINENTAL PROBLEMS.

sphere. This occasion, too, in which, after three years' sojourn in the
land of the raccoon and 'the opossum, we return to the land of the sable
and the beaver, brings forcibly to mind the continental extent of our
society and its continental field. It is not strange, then, that the conti-
nents have seemed to me a fitting theme of which to speak to you to-day.
Realizing not only the breadth and grandeur, but the inherent difficulty
of the subject, I do not hope to enlarge the contribution the decade has
made, nor shall I attempt to summarize it ; neither is it my desire to
anticipate the discussions of the World's Fair congress. It is my pur-
pose, rather, to state, as clearly as I may, some of the great unsolved
problems which the continents propound to the coming intercontinental
congress of geologists.

Differentiation of continental "n'l oceanic Plateaus. — It is one of the para-
doxes of the subject that our ideas as to the essential character of the

♦ 30,000 FT.r-

♦ 20.000 FT.

♦ I0.000 FT.

SEA LEVEL

I 0,000 FT.

2 0,000 FT.

■30,000 FT.

CONTI NENTAL
PLATEAU

OCEANIC

PLATEAU

Figure \.— Generalized Profile, showing relative Areas of the Earth's Surface at different Heights and

. Depths.

continents have been greatly modified and clarified by the recent explo-
ration of the sea. The work, especially, of the " Challenger " and the
" Blake " in delineating and sampling the bottom of the ocean has given
new definitions, not only to the term " deep sea," but also to the term
" continent," as they are employed by students of terrestrial mechanics
and of physical geography. To the continental lands are now added the
continental shoals, and the depth of the deep sea is no longer its sole
characteristic. Look for a moment at this generalized profile of the
earth's surface. It expresses in a concise way the relations of area to
altitude, and of both to the level of the sea. Murray, to whose generaliza-
tions from the "Challenger" dredgings and soundings the student of
continents owes so much, has computed, with the aid of the great body
of modern data, the areas of land and ocean bed contained between cer-

CONTINENTAL AND DEEP SEA PLATEAUS.

181

tain contours, fourteen in number * and from his figures I have con-
structed the profile. Vertical distances represent heights, and horizontal
distances represent terrestrial areas. The full width of the diagram from
side to side stands for the entire surface of the earth. The striking feat-
ures of the profile are its two terraces or horizontal elements. Two-fifths
of the earth's area lies between 11,000 and 16,000 feet beneath the ocean,
constituting a vast submerged plateau, whose mean altitude is — 14,000
feet. This is the plateau of the deep sea. One-fourth of the earth's area
falls between the contour 5,000 feet above tbe ocean and the contour
1,000 feet below, and has a mean altitude of + 1,000 feet. This is the
continental plateau. The two plateaus together comprise two-thirds of
the earth's surface, the remaining third including the intermediate slopes,
the areas of extreme and exceptional depth, and the areas of extreme and
exceptional height. Thus in the broadest possible way, and in a manner

s s

Figure 2.— The continental Plateau as related to the Western and Eastern Hemispheres.

practically independent of the distribution of land and water, we have
the ocean floor clearly differentiated from the continental plateau. It is
at once evident that for the discussion of the greater terrestrial problems
connected with the configuration of the surface, and especially of the
problems of terrestrial mechanics, we must substitute for the continents,
as limited by coasts, the continental plateau, as limited by the margins of
the continental shoals.

It does not follow from the profile, which, as I have said, represents
only the relation of extent to altitude, that all districts of continental
plateau are united in a single body, and in point of fact they are net
completely united; but the greater bodies are brought together, and the
only outlying district is that of the Antarctic continent. Running a line

* John Murray: On the height of the land and the depth of the ocean. Scottish Geographical
Mag., vol. iv, 1888, p. 1.

182 G. K. GILBERT — CONTINENTAL PROBLEMS.

along the edge of the continental shelf where a gentle slope is exchanged
for a steep one, and passing freely, as occasion may require, from the
coast down to the line of 1,000 fathoms, a continental outline is produced
in which North America and Eurasia are united through the shoals of
the Arctic ocean, and in which Australia and the greater islands of the
East Indies are joined to southwestern Asia. Antarctica alone stands
separate, being parted from South America by a broad ocean channel,
imperfectly surveyed as yet, but believed to have a depth of between
1,000, and 2,000 fathoms. The lower plateau, or the floor of the deep
ocean, is less continuous, being separated by tracts of moderate depth
into three great bodies, coinciding approximately with the Pacific, Atlan-
tic and Indian oceans.

Rigidity versus Isostasy. — The first of our continental problems refers to
the conditions under which the differentiation of the earth's surface into
oceanic and continental plateaus is possible. How are the continents
supported ? Every part of the oceanic plateau sustains the weight of
the superjacent column of water. At the same level beneath the conti-
nental plateau each unit of the lithosphere sustains a column of rock
both taller and denser than the column of water, and weighing about
three times as much. The difference between the two pressures, or the
differential pressure, is about 12,000 j:>ounds to the square inch, and this
force, applied to the entire area of the continental plateau, urges it down-
ward and urges the oceanic plateau upward. Referring again to the dia-
gram in figure l,the entire weight of the continental plateau, pressing on
the tract beneath it, tends to produce a transfer of material in the direc-
tion from left to right, resulting in the lowering of the higher plateau
* and the raising of the lower. To the question, how this tendency is
counteracted, two general answers have been made : first, that the earth,
being solid, by its rigidity maintains its form ; second, that the materials
of which consist the continental plateau and the underlying portions of
the lithosphere are, on the whole, lighter than the materials underlying
the ocean floor, and that the difference in density is the complement of
the difference in volume, so that at some level horizon far below the sur-
face the weights of the superincumbent columns of matter are equal.
The first answer regards the horizontal variations of density in the earth's
crust as unimportant; the second regards them as important. The first
may be called the doctrine of terrestrial rigidity ; the second has been
called the doctrine of isostasy. At the present time the weight of opinion
and, in my judgment, the weight of evidence lie with the doctrine of
isostacy. The differential pressure of 12,000 pounds per square inch suf-
fices to crush nearly all rocks, and it may fairly be questioned whether
there are any rock masses which in their natural condition near the sur-

CRUST AL DENSITIES. 183

face of the earth are able to resist it. The samples of rock to which the
pressures of the testing machine are applied have been indurated by dry-
ing ; but it is a fact familiar to quarrymen that rocks in general are softer
as they lie in the quarry below the water-line than after they have been
exposed to the air and thoroughly dried. It is probable, therefore, that
rocks lying within a few hundred or a few thousand feet of the surface
are unable to resist such stresses as are imposed by continents. At greater
depths we pass beyond the range of conditions which we can reproduce
in our laboratories, and our inferences as to physical conditions are less
confident. The tendency of subterranean high temperatures is surely to
soften all rocks, and the tendency of subterranean high pressures is prob-
ably to harden them. It is not known which tendency dominates; but
if the tendencies due to pressure are the more powerful, we are at least
assured by the phenomena of volcanism that their supremacy admits of
local exception.

Nature of density Differences. — If we accept the doctrine of isostasy and
regard the material under the continents as less dense than that under
the ocean floors, the question then arises whether the difference in den-
sity is due merely to a difference in temperature or whether it arises pri-
marily from differences in composition. This, which may be called the
second problem of the continents, is so intimately related to the one
which follows that we may pass it by without fuller statement.

What caused the continental Plateau ? — The problem of the origin of the
continents remains almost untouched. Those who have propounded
theories for the formation of mountain ranges have sometimes included
continents also, but as a rule without adequate adaptation to the special
conditions of the continental problem. So far as I am aware, the subject
has been seriously attacked only by our second president, Professor Dana.
He postulates a globe with solid nucleus and molten exterior, and pos-
tulates, further, local differences of condition, in consequence of which
the formation of solid crust on the liquid envelope was for a long period
confined to certain districts. In those districts successive crusts were
formed, which sunk through the liquid envelope to the solid nucleus,
and by their accumulation built up the continental masses. The re-
maining areas were afterward consolidated, and sul >s<>< |uent co< >ling shrunk
the ocean beds more than it shrunk the continental masses because their
initial temperatures (at the beginning of that process) were higher.*
That the philosophic mind may find satisfaction in this explanation, it
appears necessary to go behind the second postulate and disc-over what
were the conditions which determined congelation in certain districts
long before it began in others. Can it be shown that the localization of

* James P. Daua: Manual of Geology, 2d edition, New York, 1874, p. 738.

184 G. K. GILBERT — CONTINENTAL TROBLEMS.

congelation, having been initiated by an otherwise unimportant ine-
quality, would be perpetuated by any of those cumulative processes
which are of such importance in various departments of physics ? And
can it be shown that such a process of continent-building would segre-
gate in the continental tract certain kinds of matter, and thus institute
the conditions essential to isostatic equilibrium? To the first of these
questions no answer is apparent, but I incline to the opinion that the
second may be answered in the affirmative. If we assume the liquid
envelope to consist of various molten rocks arranged in the order of their
densities, and if we assume, further, that their order of densities in the
liquid condition corresponds to their order of densities in the solid con-
dition, then the successive crusts whose heaping built up the continents
would all be formed from the lightest material, and the isostatic condi-
tion would be satisfied.

It was the fashion of the last generation of physical geographers to
study the forms of continents as delimited by coasts, seeking analogies
of continental forms with one another, and also with various geometric
figures, especially the triangle. The generalizations resulting from these
studies have not yielded valuable ideas, and the modern student is apt
to smile at the effort of his predecessor to discover the ideal geometric
figure where the unbiased eye sees only irregularity. But barren as
were those studies I am not satisfied that their method was faulty ; and
as a physiographer I have such appreciation of the ideas that sometimes
grow from studies of form that I have attempted to apply the old method
to the new conception of the continental plateau. Confessing in advance
that my only result has been negative, I nevertheless recite what I have
done, partly because negative contributions to an obscure subject are not
entirely valueless, and partly with the thought that the forms whose
meanings I failed to discover may nevertheless prove significant to some
other eyes.

What I did was to draw upon a globe the outline of the continental
plateau and then view it from every direction. Afterwards I developed
the figure upon a plane surface, employing for that purpose a mode of
projection which is probably novel. As this mode is not susceptible of
mathematical formulation, and therefore will not find place in the litera-
ture of cartography, I may be pardoned for applying a trivial name and
calling it the orange-peel projection. The name almost explains it. Con-
ceive the continental plateau to be outlined upon a spherical orange and
the rind of the orange to be divided by a sharp knife along the sinuosi-
ties of the outline; conceive then that the portion of the rind thus cir-
cumscribed is peeled from the orange and is spread upon a flat surface,
the different parts being stretched and compressed so as to pass from

A STUDY IN FORM.

185

spherical form to plane with the least strain of the rind. The resulting
shape is delineated in figure 3. Figure 4 shows the form assumed by the
complementary part of the orange peel, which represents, of course, that
portion of the ocean outside the continental shoals. In each diagram

Figure 3. — The continental Plateau, developed on a plane Surface.

the positions of the poles, north and south, are represented by the letters
N and S. From the study of these figures, and especially from their
study as delineated on the globe, it appeared possible that a portion of
the continental plateau might belt the earth as a great circle. The dis-
covery of such a belt would be important, for by assuming that it was

N

Figure I. — Oceanic Area complementary to the continental Plateau, developed on a plane Surface.

originally equatorial we might be led to new hypotheses of continental
development. In a rotating liquid sphere the only differentiation of sur-
face condition we can readily conceive is that between equatorial and
polar regions, and if such differentiation were sufficient to cause or local-

1SG G. K. GILBERT CONTINENTAL PROBLEMS.

ize continental elevations, then these elevations would constitute either
two polar tracts or else an equatorial belt. Moreover, I have been in-
duced by recent studies of the physical history of the moon to suspect
that the earth may at one time have received considerable accessions
from without, and that these accessions were made to the equatorial tract.
If these suspicions are well founded, peculiar characters may have been
given to a tract having the form of a belt. So for a double reason I was
led to compare the outline of the continental plateau with a great circle-
To this end a great circle was chosen, coinciding as nearly as possible
with the line of greatest continental extension, and the projection was so
•modified as to render the locus of that great circle a straight line. The
result appears in figure 5, where the straight line is the projection of the
hypothetic ancient equator; and j-ou will probably agree with me that
it gives little support to the suggestion that the principal line of conti-
nental elevation was originally equatorial.

Figure 5. — Area of continental Plateau, developed with Reference to a great Circle.

Why do continental Areas rise and fall f — A fourth problem refers to con-
tinental oscillations. The geologic history of every district of the land
includes alternate submergence under and emergence from the sea. To
what extent are these changes due, on one hand, to movements of the sea
and, on the other, to movements of the land, and what are their causes?
With American geologists the idea, recently advocated, that the chief
movements are those of the ocean finds little favor, because some of the
most important of the changes of which we are directly cognizant are
manifestly differential. Our paleozoic map pictures a sea where now are
Appalachian uplands, and uplands where now are low coastal plains and
oceanic waters. In Cretaceous time the two margins of what are now the
Great Plains had the same height, or at least the western margin was no
higher than the eastern ; but now the western margin lies from four thou-
sand to six thousand feet above the eastern, and the intervening rock
mass appears to have been gently tilted without important internal dis-
tortion. Such geographic revolutions are not to be explained by the
shifting of the hydrosphere nor by its dilatation and contraction. Neither
can they be ascribed to isostatic restoration of an equilibrium deranged

OSCILLATION, PERMANENCE, GROWTH. 187

through the transfer of masses by erosion and sedimentation, for that
hypothetic process is essentially conservative. Neither is it easy to be-
lieve that the two margins of the plains have differed, since the Creta-
ceous, to the extent of one mile in their radial contraction due to secular
cooling of the globe ; nor is it easy, at least for the disciple of isostasy, to
believe that such a change can have resulted from the localization of
deformation consequent on the slowing of the earth's rotation. Each of
these processes may have been concerned, but I conceive that the essen-
tial factor still awaits suggestion. Our knowledge of surface processes, as
compared to subterranean, is so full that the field of plausible epigene
hypotheses may be exhausted, but the vista of hypogene possibility still
opens broadly.

Are Continents permanent ? — The doctrine of the permanence of the con-
tinental plateau, enunciated long ago by Dana and more recently advo-
cated, with a powerful array of new data, by Murray and Wallace, has
made rapid progress toward general acceptance. Nevertheless its course
is not entirely clear, and among the obstacles still to be overcome is one
whose magnitude is perhaps magnified for the American student by prox-
imity. All who have studied 1 iroadly the stratigraphy of the Appalachian
district have concluded that the sediments came chiefly from the east;
and the detailed Appalachian work of the past decade is disclosing a
complicated history, in which all chapters tell of an eastern paleozoic
land, and some chapters seem to testify to its wide extent. At some
times the western shore of this land lay east of the site of the Blue Ridge,
and there is serious doubt whether the existing belts of coastal plain and
submerged continental shelf afford it sufficient space. For the present,
at least, the subject of continental permanence must be classed with the
continental problems.

Do Continents grow? — According to my own view, there is yet another,
a sixth, continental problem deserving the attention of the World's Fair
intercontinental congress. We have been told by the masters of our
science, and their teaching has been echoed in every text-book and in
every class-room, that through the whole period of the geologic record
the continents have grown ; not that the continental plateaus have been
materially extended, not that the pendulum has moved always in one
direction, but that the land area has, on the whole, steadily increased.
From this doctrine there has been no dissent — and possibly there should
be no dissent — but the evidence on which it is founded appears to me so
far from conclusive that I venture to doubt.

The evidence employed consists partly in the general distribution of
formations as shown by the geologic map and partly in inferences drawn
from certain formations which contain internal evidence that they orig-

XXVIII-Bull. Geol. Soc. Am., Vol. 4, 1892.

188 G. K. GILBERT — CONTINENTAL PROBLEMS.

inated on coasts. With the aid of such data are drawn the outlines of
ancient ocean and land at various geologic dates, and from the compari-
son of these outlines continental growth isinferred. In passing from the
formation boundaries of the geologic map to the oceanic limits of the
charts of ancient geography, allowance is made for the former extent of
non-littoral formations beyond their present boundaries. Tins allowance
is largely conjectural, and the range of possible error is confessedly great.
In passing from the observed limits of littoral formations to the coast
lines of ancient geography little or no allowance is usually made for the
former extent of the formations, and I conceive that great possibility of
error is also thus admitted. During a period of oceanic transgression
over the land all portions of the transgressed surface are successively
coastal, and the coastal deposits they receive are subsequently buried by
off-shore deposits. When, therefore, littoral beds are found in remnants
of strata surviving the processes of degradation, it is indeed proper to
infer the proximity of ancient coasts during their formation, but the in-
ference that they represent the limit of transgression for that epoch may
be far from the truth. For these reasons it appears to me that the spe-
cific conclusions which have been reached with reference to the original
extent of various formations are subject to wide uncertainties; and if
this be granted, then but brief attention to a simple law of denudation is
necessary to show that the general conclusion may be illusory. The
process of degradation by aqueous agencies is chiefly regulated, not by
the thickness of formations, hut by the height to which they are uplifted.
Thus the present extent of most formations is determined in large part
by crustal oscillations subsequent to their deposition. As formations are
progressively eroded, the underlying and older cannot be attacked until
the overlying and younger have been carried away, and so the outcrops
of the older of necessity project beyond the boundaries of the younger.
The process of vague inference, making indefinite allowance for the un-
known quantity of eroded strata, nearly always assigns to the older for-
mation, which projects visibly beyond the newer, a greater original
extent. It appears to me thus possible that the greater part of the data
from which continental growth is inferred maybe factitious and mislead-
ing.

Furthermore, inference, such as it is, deals with only one phase of the
problem. It is applied to the incursions of the sea upon the land, but it
is not applied to the excursions of the land upon the sea. Just as we
infer from stratified rocks the presence of the sea, so also we infer from
unconformities the sea's absence; and to the student of ancient geography
the two classes of evidence are equally important. But the strata, spread
widely over the surface of the land, are conspicuous phenomena, while

DO CONTINENTS GROW? 189

unconformities are visible only here and there and are usually difficult
of determination. For this reason the data from unconformity have
never been assembled. Essays toward ancient geogra | >1 iv have dealt only
with the minima of ancient land, never with its maxima, and the ques-
tion of continental growth cannot be adequately treated while half of the
history is ignored.

We may borrow a figure from the strand of a lake. As the waves roll
inward, each records its farthest limit by a line upon the sand, and each
obliterates all previous wave lines which it overpasses. The observer
who studies the transient record at any point may find a series of lines,
of which the highest is the oldest and the lowest is the newest, and he
may infer that the lake level was higher when the first wave left its
trace, and that the water is receding from the land. But if he continue
his observations through many days and fix monuments to record from
time to time the lowest land laid bare between the waves, he may dis-
cover that the highest wave line and the lowest record of ebb correspond
in time with the play of the largest waves, and that the lowest wave line
and the highest record of ebb correspond to the play of smaller waves,
and thus reach the conclusion that the lake level has remained unchanged.
In the study of Time's great continental strand Ave are not even able to
observe directly the wave lines of rhythmic transgression, but infer their
positions from data often ambiguous, and of the lower wave limits, the
lines of maximum regression, we are absolutely ignorant.

It may be true that it priori considerations afford a presumption in
favor of continental growth, but such presumption should not be per-
mitted to give color to evidence otherwise neutral ; and, moreover, it is
not impossible to discover an a priori presumption in favor of continental
diminution. Assuming that hypogene agencies cause continental areas
to rise above the ocean, the work of epigene agencies constantly tends to
remove the projecting eminences and deposit their material about their
margins, so as to extend the area of the continental plateau. Thus we
have a strong a priori presumption in favor of continental growth. On
the other hand, if we admit the principle of isostatic equilibrium, then
the continental eminences have low density ; and as they are worn away
by epigene processes the material which rises from below to restore them
has greater density and maintains a somewhat less altitude. The pro-
cess of isostatic restoration tends thus toward the permanent leveling of
continents, and if the hypogene initiative should cease the continents
would ultimately be reduced to ocean level, and finally, through pro-
cesses of solution, to a level below the ocean ; so, assuming the initiative
processes of the under earth to be of finite duration, the work of terres-
trial degradation, combined with isostatic restoration, should afford a

190 G. K. GILBERT — CONTINENTAL PROBLEMS.

continental history characterized in an earlier stage by growth and in a
later stage by decadence. In our ignorance of subterranean forces we
should use such a priori considerations only as a means for the sugges-
tion of hypotheses. As they have doubtless served to promote the theory
of continental growth, they should also he permitted to indicate the pos-
sibility of continental retrogradation.

Summary. — The problems of the continents have been touched to-day
so briefly that a summary is almost superfluous. The doctrine of isos-
tasy, though holding a leading position, has not fully supplanted the
doctrine of rigidity. If it be accepted, there remains the question whether
heat or composition determines the gravity of the ocean beds and the
levity of continents. For the origin of continents we have a single hy-
pothesis, which deserves to be more fully compared with the body of
modern data. The newly determined configuration of the continental
mass has yielded no suggestion as to its origin. The cause of differential
elevation and subsidence within the continental plateau is unknown and
has probably not been suggested. The permanence of the continental
plateau, though highly probable, is not yet fully established ; and the
doctrine of continental growth, though generally accepted, has not been
placed beyond the field of profitable discussion. Thus the subject of
continents affords no less than a half dozen of great problems, whose
complete solution belongs to the future. It is not altogether pleasant to
deal with a subject in regard to which the domain of our ignorance is so
broad ; but if we are optimists we may be comforted by the reflection
that the geologists of this generation, at least, will have no occasion, like
Alexander, to lament a dearth of worlds to conquer.

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA
Vol. 4, pp. 191-204 March 24, 1893

COMPARISON OF PLEISTOCENE AND- PRESENT ICE-SHEETS

BY WAR REX UPHAM

[Read before the Society December 29, 1892)
CONTENTS

Page

Existing Ice-sheets and Glaciers 191

The Antarctic Ice-sheet 192

The Greenland Ice-sheet 192

The Malaspina Glacier or Ice-sheet 194

The Mnir Glacier 196

Inferences from Comparisons of present and Pleistocene Ice-aheets 198

Probable surface Slopes and Thickness of the Pleistocene Ice-sheets of

North America and Europe 19S

Probable Rates of Er< >si< >n by Pleistocene Ice-sheets 199

Subglacial and englacial Transportation of Drift 199

Rapidity of final Ablation of the Ice-sheets 200

Modes of Deposition of the englacial Drift 201

Origin of Forest Beds between Deposits of Till 201

The Ice Age viewed as a continuous and geologically brief Period 202

General Consideration of the Question 202

Probable Synchronism of Glaciation in North America and Europe 203

Relation of the Ice Age to human and geologic History 204

Existing Ice-sheets and Glaciers.

The guiding principle of geologic investigation, brought out most clearly
by Lyell, requires us to seek the explanation of past changes of the earth
by observation and study of agencies which are now in operation, pro-
ducing similar changes during the present epoch. From such studies of
the Swiss glaciers, Agassiz, Forbes, Tyndall and others have given to us
the theory of the formation of the drift by land ice, so that the compara-
tively small district of the Alps supplied the clue for deciphering the
records of the latest completed chapter of the geologic history of north-
western Europe and the northern half of North America. Glaciers of
other regions in the eastern hemisphere, notably of the Himalayas and

XXIX-Bull. Geol. Soc. Am., Vol. 4, 1892. " (191)

192 W. TJPIIAM — PLEISTOCENE AND PRESENT ICE-SHEETS.

of Norway, have also contributed much to our knowledge of the ice-sheets
of the Pleistocene or glacial period. The vast ice-sheets of that time,
however, are adequately exemplified at the present day only by the
Antarctic and Greenland ice-sheets, less completely and on a much
smaller scale by the yet very instructive Malaspina glacier, and in some
respects they may be profitably compared with the Muir glacier, which
is the most fully studied ice-field of America or perhaps of the world.

The Antarctic Ice-sheet. — Land ice surrounds the south pole to a distance
of 12 to 25 degrees from it, covering, according to Sir Wyville Thomson,
about 4,500,000 square miles. Its area is thus slightly greater than that
of the Pleistocene ice-sheet of North America, which covered about
4,000,000 square miles, while the confluent Scandinavian and British
ice-sheets appear to have enveloped no more than 2,000,000 square miles,
including the White, Baltic, North and Irish seas, whose areas were then
occupied by the continental mer de glace. Whether the Antarctic ice-
sheet covered an equal or greater extent in the Pleistocene period, con-
temporaneous with the glaciation of now temperate regions, we have no
means of knowing. Along a portion of its border of perpendicular ice-
cliffs Sir J. C. Ross sailed 450 miles, finding only one point low enough
to allow the upper surface of the ice to be viewed from the masthead.
There it was a smooth plain of snowy whiteness, extending as far as the
eye could see. That this ice-plain has a considerable slope from its cen-
tral portions toward its boundary is shown by its abundant outflow into
the sea, by which its advancing edge is uplifted and broken into multi-
tudes of bergs, many of them tabular, having broad, nearly flat, tops.
As described by Moseley in " Notes by a Naturalist on the Challenger"
these bergs give strange beauty, sublimity and peril to the Antarctic
ocean, upon which they float away northward until they are melted.
Many parts of the borders of the land underlying this ice-sheet are low
and almost level, as is known by the flat-topped and horizontally strati-
fied bergs, but some other areas are high and mountainous. Due south
of New Zealand the volcanoes Terror and Erebus, between 800 and 900
miles from the pole, rising respectively about 11,000 and 12,000 feet above
the sea, suggest that portions or the whole of this circumpolar continent
may have been recently raised from the ocean to form a land surface,
which on account of its geographic position has become ice-clad.

The Greenland Ice-sheet. — Inside its border of mountains Greenland is
enveloped by an ice-sheet which lias a length of about 1,500 miles, from
latitude 60° 40' to latitude 82°, with a probable average width of 400
miles or more, giving it an area of 600,000 square miles. On the easf
this ice-sheet in some places stretches across the mountains, and the coast-
consists of its ice-cliffs; and on the west glaciers flow from the inland ice

WORK OF ARCTIC EXPLORERS. 193

through gaps of the mountains to the heads of the many fjords and bays,
where the outflowing ice is broken into bergs of every irregular shape
and borne away by the sea. One of. these ice-streams, discovered and
named by Kane the Humboldt glacier, is 60 miles wide where it enters
Peabody bay, above which it rises in cliffs 300 feet high.

The altitude and slopes of the Greenland ice-sheet have been deter-
mined by Nordenskiold, Peary, and Nansen. Nordenskiold's journey in
July, 1870, to the east from the head of Aulatsivik fjord, near latitude
68° 20', is estimated to have extended about 35 miles upon the ice-sheet,
and the altitude reached was 2,200 feet. From nearly the same starting
point, Nordenskiold, in July, 1883, went onto the ice-sheet about 73
miles, to a height of about 4,950 feet ; and two Lapps, traveling with the
peculiar snowshoes called " ski," advanced a probable distance of 45 or
50 miles farther, where the barometers indicated a height of 6,386 feet.
Land in the interior, free of ice and bearing vegetation, which Norden-
skiold hoped to reach, was not found ; and no nunatak, or projecting top
of hill or mountain, above the ice surface has been yet discovered more
than 40 or 50 miles inside the ice-covered area.

Lieutenant R. E. Peary, of the United States Navy, in June and July,
1886, accompanied by Christian Maigaard, made the next important ex-
ploration of the inland ice, going eastward from the head of Pakitsok
fjord, on the northeastern part of Disco bay, in latitude 69° 30'. They
advanced to a distance of about 100 miles from the edge of the ice, at-
taining an altitude of about 7,500 feet. In concluding the narrative of
this journey* after describing the needful outfit, Peary remarked: "To
a small party thus equipped, and possessed of the right mettle, the deep,
dry, unchanging snow of the interior ... is an imperial highway,
over which a direct course can be taken to the east coast." It was also
suggested that the unexplored northern shore lines of Greenland may be
most readily mapped by expeditions across the high inland ice. This
sagacious suggestion Peary has since in part fulfilled by his very success-
ful expedition from May 15 to August 6 of this year, in which he crossed
the northwestern and northern parts of this ice-sheet, reaching altitudes
of 5,000 to 8,000 feet, and determining approximately the northern bound-
ary of the ice from Petermann fjord to the eastern coast at Independence
bay, in latitude 81° 37' and longitude 34° west from Greenwich.

In August and September, 1888, Dr Fridtjof Nansen, with five com-
panions, crossed the ice-sheet of Greenland from east to west between
latitude 64° 10' and 64° 45'. The width of the ice there is about 275
miles, extending into the ocean on the east, but terminating on the west

*"A Reconnoissance of the Gfreenland Inland [ee," Bull. Am. Geog. Soc, vol. xix, pp. 201-2-'^
September 30, 1887.

194 W. UPHAM — PLEISTOCENE AXI> PRESENT ICE-SHEETS.

about 14 miles from the head of Ameralik fjord and 70 miles from the
outer coast line. For the first 15 miles in the ascent from the east, rising
to the altitude of 1,000 meters, or 3,280 feet, the average gradient was
nearly 220 feet per mile. In the next o5 miles an altitude of 2,000 meters,
or 6,560 feet, was reached; and the average gradient in this distance, be-
tween 15 and 50 miles from the margin of the ice, was thus about 94
feet per mile, or a slope very slightly exceeding one degree. The highest
part of the ice-sheet, about 112 miles from the point of starting, was
found to have an altitude of 2,718 meters, or about 8,920 feet. Its ascend-
ing slope, therefore, in the distance from 50 to 112 miles was about 38
feet per mile. Thence descending westward, the gradients are less steep,
averaging about 25 feet per mile for nearly 100 miles to the altitude of
2,000 meters, about 63 feet per mile for the next 52 miles of distance and
1,000 meters of descent, and about 125 feet per mile for the lower western
border of the ice*

But Greenland has not always been thus ice-enveloped. During the
middle or earlier portions of the Tertiary era forest trees belonging to a
temperate flora extended northward in western Greenland to the Arctic
circle. Going much farther back to inquire the origin of this great island,
we find that it is an outlier of the North American plateau of Archaean
rocks, which comprises also Ellesmere land, the eastern part of North
Devon, Baffin land, Labrador and the country around Hudson bay,
stretching thence southwestward to lakes Huron, Superior and Winnipeg,
and westward to Athabasca, Great Slave and Great Bear lakes, and to
Coronation gulf of the Arctic sea. The greater part of the Arctic archi-
pelago, however, consists of Paleozoic strata. During long Mesozoic and
Tertiary ages of higher altitude of these regions subaerial stream erosion
formed the channels which divide the Arctic islands, the basin and valley
of Hudson bay and strait and those of Baffin bay and Davis strait, which
now by subsidence separate Greenland from the mainland. More ample
oceanic circulation, carrying warmth from tropical and temperate latitudes
to the Arctic sea, was probably the cause of the formerly luxuriant vegeta-
tion of Greenland ; but during the ensuing Pleistocene period its ice-sheet
was for some time even more extended and deeper than now, as is shown
by the glaciation of the rock surface high up on the sides of the fjords.

The Malaspinet, Glacier or Ice-sheet. — The comparatively small Malaspina
ice-sheet, stretching from the Saint Elias range to the shore of the Pacific
ocean, has been described as follows by its principal explorer, Professor
I. C. Russell, after his two expeditions of 1890 and 1891 : f

*The First Crossing of Greenland, 2 vols., 1890.

f" Mount Saint Elias and its Glaciers," Am. .lour. Sci., III, vol. xliii, pp. 169-182, with map, March,
1892. The report of the first expedition, in 1890, is given by Russell in the National Geographic
Blagazine, vol. iii, pp. 53-203, with 19 plates, and <s figures in the text, May 29, 1891.

RUSSELL ON MALASPINA GLACIER. 195

This glacier extends with unbroken continuity from Yakutat bay seventy miles
westward, and has an average breadth of between twenty and twenty-five miles ;
its area is approximately 1,500 square miles, ... a vast, nearly horizontal
plateau of ice, with a general elevation of about 1,500 feet. The central portion is
free from moraines and dirt, but is rough and broken by thousands and tens of
thousands of small crevasses. Its surface is broadly undulating, and recalls the
appearance of portions of the rolling prairie lands west of the Mississippi. . . .
On looking down on the glacier from an elevation of two or three thousand feet on
the hills bordering it on the north, even on the wonderfully clear days that follow
storms, its limits are beyond the reach of vision. From any commanding station
overlooking the Malaspina glacier, as from the summit of the Chaix hills, for ex-
ample, one sees that the great central area of clear, white ice is bordered on the
south by a broad, dark band formed of bowlders and stones. Outside of this, and
forming a belt concentric with it, is a forest-covered area, in many places four or
five miles wide. . . .

The moraines not only cover all of the outer border of the glacier, but stream off
from the mountain spurs that project into its northern border. . . . The stones
and dirt previously contained in the glacier are . . . concentrated at the sur-
face, owing to the melting of the ice that contains them. This is the history of all
of the moraines of the Malaspina glacier. They are formed of the debris brought
out of the mountains by the tributary Alpine glaciers, and concentrated at the sur-
face by reason of the ablation of the ice. . . .

The outer and consequently older portions of the fringing moraines are covered
with vegetation, which in places, particularly near the outer margin of the belt, has
all the characteristics of old forests. It consists principally of spruce trees, some of
which are three feet in diameter, and cottonwood, alder and a great variety of
shrubs and bushes, together with rank ferns, which grow so densely that one can
scarcely force a passage through them. The vegetation grows on the moraines rest-
ing on the ice, which in many places is not less than a thousand feet thick. . . .
It is only on the stagnant border of the ice-sheet that forests occur. The forest-
covered area is, by estimate, between twenty and twenty-five square miles in
extent.

The drainage of the Malaspina glacier is almost entirely interglacial or subglacial.
There is no surface drainage, excepting in a few localities where there is a surface
slope, but even in such places the streams are short and soon plunge into a crevasse
or a moulin and join the drainage beneath.

On the lower portions of the Alpine glaciers, tributary to the Malaspina, there
are sometimes small streams coursing along in ice channels, but they are short-
lived. ( )u the borders of these tributaries there are frequently important streams,
flowing between the ice and a mountain slope, but where these come down to the
Malaspina they flow into tunnels and are lost to view.

Alongthe southern margin of the Malaspina glacier, between the Yahtse and
Point Manby, there are hundreds of streams which pour out of the escarpment
formed by the border of the glacier, or rise like great fountains from the gravel and
bowlders at its base. All of these streams are brown and heavy with sediment and
overloaded with bowlders and stones.

One of the largest streams draining the glacier is the Yahtse. This rises in two
principal branches at the base of the Chaix hills, and, flowing through a tunnel
some six or eight miles long, emerges at the southern border of the glacier as a

196 W. UPHAM — PLEISTOCENE AND PRESENT ICE-SHEETS.

swift, brown flood, fully one hundred feet across and fifteen or twenty feet deep.
The stream, after its subglacial course, spreads out into many branches, and lias
built up an alluvial fan which has invaded and buried thousands of acres of forest.
In traversing the coast from the Yahtse to Yakutat bay, we crossed scores of ice-
water streams which drain the ice-field to the north. The greater part of these
could be waded, but some of them are rivers which it was impossible to ford.

Oogenic disturbances formed the Saint Elias range since the begin-
ning of the Pleistocene period, for its basal portion consists of the late
Pliocene and Pleistocene Pinnacle and Yakutat formations, above which
the Saint Elias schist has been overthrust. Fossil marine shells, all of
which .are represented by species now living in the adjacent ocean, were
collected by Russell in the cliffs above Pinnacle pass at the height of 5,000
feet above the sea. The following summary of the history of this range
is given by Russell : *

Not only was a part, at least, of the Pinnacle system deposited during the life of
living species of mollusks, but also the whole of the Yakutat series, the stratigraphic
position of which is, if my determination is correct, above the Pinnacle system.
After the sediments composing the rocks of these two series were deposited in the
sea as strata of sand, mud, etc., they were consolidated, overthrust, faulted and up-
heaved into one of the grandest mountain ridges on the continent. Then, after the
mountains had reached a considerable height, if not their full growth, the snows of
winter fell upon them, and glaciers were born. The glaciers increased to a maxi-
mum, and their surfaces reached from a thousand to two thousand feet higher than
now on the more southern mountain spurs, and afterward slowly wasted away to
their present dimensions. All of this interesting and varied history has been en-
acted during the life of existing species of plants and animals.

The Muir Glacier. — According to the descriptions and maps of Pro-
fessors G. Frederick Wright f and H! F. ReidJ and Mr H. P. Gushing, ||
the Muir glacier, which is situated some 200 miles southeast of Mount
Saint Elias, has an area of about 350 square miles, and the area inclosed
by its watershed is about 800 square miles. It receives many tributary
glaciers, whose areas are included in this estimate. The slope of the
main glacier for 10 miles or more next to its termination in the sea at
the head of Glacier bay is about 100 feet per mile. Its frontal cliffs,
which shed multitudes of bergs into the sea, had in 1890 an extent of If
miles, and rose in a vertical wall of ice 130 to 210 feet above the water,
which, within 300 feet from the ice-front, has a maximum depth of 720
feet. Between the observations of Professor Wright in 1886 and those of

*Nat. Geog. Mag., vol. iii, pp. 172, 173.

t Am. Jour. Sci., III, vol. xxxiii, pp. 1-18, with map, January, 1887 : The Ice Age in North America,
1889, chapter iii.
J Nat. Geog. Mag., vol. iv, pp. 19-84, with 16 plates and 5 figures in the text, March 21, 1892.
|| Am. Geol., vol. viii, pp. 207-230, with map, October, 1891.

RATE OP GLACIAL FLOW. 197

Reicl and Gushing in 1890, the ice-front had receded one-third to two-
thirds of a mile.

In 1886 the height of the ice-cliffs above the water was found by Wright
to be 250 to 300 feet, and the rates, of forward motion of the most promi-
nent ice pinnacles near to the front and within a half mile back from it
were roughly measured by him and found to vary from 160 feet to 9 feet
per day, the maximum being that of a pinnacle close to the projecting
middle of the terminal cliffs. In 1890, however, Reid and Gushing
measured the rates of the glacial currents in a more accurate way by
observations of flags set on the surface of the glacier one-fourth to one-
half of a mile back from its then nearly straight and much lower front,
and found the maximum movement near the center to be only about
seven feet per day. In respect to the apparent discrepancy of these de-
terminations in 1886 and 1890, it is to be remarked that the ice pinnacles,
belonging to the most fractured and crevassed portions of the glacier,
probably move onward faster than its more even tracts, which can be
traversed and marked by flags, and that the two different years between
which the front was withdrawn so far may have been considerably unlike
in the meteorologic conditions governing the flow of the glacier. The
abundant observations of Helland, Steenstrup and others on the rates of
outflow of glaciers into the fjords and bays of the western coast of Green-
land show that there the glacial advance ranges frequently from 30 to 65
feet daily, and in at least one case is about 100 feet.* Narrow glaciers
in Alpine valleys move only a few feet daily ; but the broad glaciers
of polar regions, when they terminate in the sea, often move at their
ends much more rapidly, as 30 to 50 feet or more per day.

The Muir glacier, like the Malaspina ice-sheet and other glaciers of the
Saint Elias region, is fast retreating. From the narrative of Vancouver's
exploration of this coast in 1794, and from observations by Wright, Reid,
and Gushing, of freshly glaciated rock surfaces far outside and also far
above the present glacier, it appears sure that only one to two centuries
ago the Muir glacier stretched some twenty miles farther than now, nearly
to the mouth of Glacier bay. Its advance to this maximum area had
perhaps occupied a considerably longer time than its retreat, but the
whole time of both advance and recession appear to be geologically
recent. In its forward movement forests became enveloped in the gravel
and sand discharged by streams from the glacier, and they were then
overridden by the ice advance, so that now on its retreat the still stand-
ing trees are being uncovered by the channeling of streams.

During the summer of 1890 the rate of ablation of the frontal part of

*H. Rink: "The Inland Ice of Greenland," Scottish Geog. Mag., vol. v, L889, pp. 18-28. Nature,
December 29, 1887.

198 W. UPHAM PLEISTOCENE AND PRESENT ICE-SHEETS.

the Muir glacier was about 14 inches per week, which would lower its
surface probably 15 or 20 feet in the whole season. This corresponds
approximately with the ablation of the Mer de Glace in Switzerland,
ascertained by Forbes to be 241 feet between June and September in
1842, while in some exceptional cases the ablation of glaciers in summer
has been found to be as much as one foot a day.

One other point of great significance brought out by these investigations
of the Muir glacier is the approximate determination of the rate of gla-
cial erosion upon its rock bed. Measurements of the sediment in the
water of the copious subglacial streams, and estimates of the quantity of
water annually discharged from the rainfall and snowfall of the Muir
basin, indicate, according to Wright's computations, an average erosion
of one-third of an inch for all the ice-clad area in a year, while according
to Reid it would be about three-fourths of an inch.

Inferences from Comparisons of present and Pleistocene Ice-
sheets.

Probable surface Slopes and Tliickness of the Pleistocene Ice-sheets of North
America and Europe. — In North America the upper limits of the Pleisto-
cene glaciation on mount Katahdin, the Catskills, the Three buttes or
Sweet Grass hills of Montana, the Rocky mountains north of the inter-
national boundary, and the mountains of British Columbia, give us reli-
able information of the thickness of the ice-sheet in the vicinity of these
high elevations of land. Its depth is computed by Dana to have been
about two miles on the Laurentide highlands, between the Saint Law-
rence and Hudson bay, whence the ice flowed radially outward in all
directions, during its maximum stage overtopping the White, Green and
Adirondack mountains. In British Columbia, according to Dr G. M.
Dawson, its maximum depth was about 7,000 feet. These thicknesses,
however, which seem well determined, would not give to the borders of
the North American ice-sheet surface slopes of more than about 25 to 30
feet per mile, whereas the Greenland ice-sheet is known to have surface
gradients of 100 to 200 feet per mile. Apparently slopes of at least 50
feet or more per mile for the outer portion of the ice-sheet are required
to produce strong glacial currents, such as transported bowlders 1,000
miles, from the eastern side of the southern part of Hudson bay where it
narrows into James bay south westward to southern Minnesota, and such
as carried Scandinavian bowlders likewise about 1,000 miles, from their
sources to central Russia. The Pleistocene ice-sheets could have had
gradients comparable in steepness with those of the Greenland ice-sheet
only by epeirogenic uplifts of the central portions of their areas to heights

DEPTHS OF FJORDS. 199

at least several thousand feet above their present altitudes. These
epeirogenic movements of uplift, suggested by the ice-sheet of Green-
land, I believe to have been the cause of the climatic changes by which
the ice-sheets of North America and Europe were accumulated.

The depth of the fjords and now submarine valleys on the coasts of
the northern half of our continent indicate that the borders of our glaci-
ated area were mostly uplifted 2,000 to 3,000 feet, and the preglacial ele-
vation of the central parts of Canada was probably 5,000 feet or more,
giving the necessary slope for the outflow of the ice-sheet, excepting so
far as that outflow was due to the thickness of the ice. The same argu-
ments for high preglacial altitude of Scandinavia have been recently well
stated by Mr T. F. Jamieson, who notes the depth of the Christiania
fjord as 1,380 feet, of the Hardanger fjord, 2,624 feet, and of Sogne fjord,
the longest in Norway, 4,080 feet.*

Probable Rates of Erosion by Pleistocene Ice-sheets. — The Muir glacier is
found to be eroding its rock bed at the rate of about three-fourths of an
inch yearly, or one foot in sixteen years, and six feet in a century.
Doubtless the erosion by the ice-sheets of the glacial period was equally
rapid in the zone of most efficient action, which may have been usually
from 50 to 200 miles inside the ice boundary. In 1,000 years this zone
would be eroded to an average depth of 40 feet, and in 5,000 years 200
feet. Farther within the ice-covered area the erosion was probably some-
what less, but during the recession of the ice-sheet, and perhaps also dur-
ing its accumulation, the maximum rate of erosion would prevail succes-
sively upon all parts of the drift-bearing regions. In the light of this
comparison with the modern Muir glacier, it is evident, from the volume
of the drift and the topographic features of the country, that a geologic-
ally brief period, at the longest perhaps 10,000 or 20,000 years, would
suffice for the observed volume of the Pleistocene glacial erosion and re-
sulting drift.

Subglacial and englaciat Transportation of Drift. — Under this heading an
ample discussion would require much space. It may be therefore suf-
ficient to state that the observations of the inland ice of Greenland by
Hoist and of the Malaspina glacier by Russell, reaffirming the conclu-
sions reached through investigations of the North American drift by
Dana, Shaler, C. H. Hitchcock, N. H. Winchell and others, including
myself, seem to me to prove undeniably that the Pleistocene ice-sheets
contained much drift in their lower portions to heights of probably 1,000
to 1,500 feet above the ground. This transportation of drift within the
ice seems to me to have been equally important, and almost equal in
amount, with the subglacial transportation. Professor James Geikie,

*Geol. Mag., Ill, vol. viii, pp. 387-392, September, 1891.
XXX— Bull. Gkol. Soc. Am., Vol 4, 1892.

200 W. Uril AM PLEISTOCENE AND PRESENT ICE-SHEETS.

however, in Great Britain, and Chamberlin and Salisbury, with McGee

and others, in this country, think that there was only very scanty
englacial drift. My reasons for believing that it was of large amount I
have stated in several recent papers, three of which have been presented
before this Society *

Rapidity of final Ablation of the Ice-sheets. — The rates of observed abla-
tion of the Muir glacier and the Mer de Glace suggest that during the
closing stage of the glacial period the ice-sheets may have been melted
away very fast. If such ablation prevailed every summer for one or two
centuries, it must melt 2,000 ttf 4,000 feet of ice, which was approxi-
mately the thickness of the Pleistocene ice-sheet from central New Eng-
land westward across the Laurentian lakes to Minnesota and southern
Manitoba. This accords with the apparent duration of the glacial lake
Agassiz for only about 1,000 years, and with the evidently very rapid
accumulation of the eskers, of their associated sand plains and plateaus,
of the valley drift, and also, as I confidently think, of the drumlins.
There were indeed many times of halt or readvance of the ice-front, in-
terrupting its general retreat, as shown by the terminal moraines, of
which Professor Chamberlin, Mr Frank Leverettand others have mapped
no less than fifteen or twenty in their order from south to north in Ohio,
Indiana, Illinois, and southern Michigan; but such halts forming large
moraines on each side of Lake Agassiz were demonstrably of short con-
tinuance, only for a few decades of years, and the whole departure of the
ice-sheet from the southern end of this glacial lake to Hudson bay was
geologically very rapid.

The causes for the sudden departure of the ice were therefore probably
as exceptional and unique in their character as for its accumulation, and
I think that they were indeed exactly the reverse of those before assigned
for the inauguration of the glaciation. Beneath the load of ice thousands
of feet thick the land sank, and when the ice-sheets were at their maxi-
mum area and during their retreat the glaciated lands stood mostly some-
what lower than now. The depression from the preglacial altitude was
virtually equivalent to a transfer of the Greenland ice-sheet to the present
temperate latitudes and comparatively low lands of the provinces of
Quebec and Ontario and the northern United States, where that vast
sheet of ice would be rapidly melted during all the summer months and
more slowly in spring and autumn, until within probably a few hundred
years it would entirely disappear.

♦"Inequality of Distribution of the Englacial Drift," Bull. Geol.Soc. Am., vol. iii, 1891, pp. 134-148.
''Criteria of Englacial and Subglacial Drift,"' Am. Geo!., vol. viii, pp. 37G-3S5, December, 1891.
" Conditions of Accumulation of Drumlins" (presented in preliminary outlines at the Rochester
meeting of the Geological Society, August, 1892), Am. Geol., vol. x, pp. 339-362, December, 1892.
"Eskers near Rochester, X. V." read before the Society at this Ottawa meeting.

MODES OF GLACIAL ACTION. 201

Modes of Deposition of the englacial Drift. — Again, on this topic, which,
like the ways of transportation of the drift, would need too much space,
for its adequate presentation here, I may refer to my several papers before
cited. It is desirable, however, to call special attention to the discrimina-
tion by Hoist of the enclosed drift and the subglacial drift of the Green-
land ice-sheet * In New England and in Minnesota, the Dakotas, and
Manitoba, I find corresponding divisions of the sheet of till, the lower
part being shown by its hard and compact condition and by other
characters to be the ground moraine of the ice-sheet, while the upper
part, which is comparatively loose, with more plentiful large bowlders,
appears to have been dropped from an englacial or superglacial position
when the ice melted.

Russell, in the later paper already quoted from, discusses in a very
instructive manner, by analogy with the products of the Malaspina
glacier, the origin of Pleistocene eskers and kames, glacial flood-plains of
gravel and sand, and somewhat similar high lacustrine plains and ter-
races. All the explanations which he thus gives are undoubtedly appli-
cable generally or at least in some localities to the drift formations of the
Glacial period ; but, as noted in my foregoing paper on the Pinnacle hills
and Pittsford eskers, near Rochester, New York, I think that mainly the
retreat of the Pleistocene ice-sheet was so rapid that its drainage then
was almost wholly by superglacial streams, in whose open channels the
eskers of the northern United States and Manitoba, so far as I have
studied them, appear to have been formed.

The accumulation of drumlins, which has been so difficult of explana-
tion, seems to me referable to convergent currents of the ice-sheet during
its retreat amassing its englacial drift in these peculiarly moulded hills,
this drift having been first exposed on the ice surface by ablation, like
that on the outer part of the Malaspina glacier, then enveloped again in
the ice as a drift stratum, and finally carried into these accumulations
beneath the ice.f

Origin of Forest Beds between Deposits of Till— On extensive tracts of the
Mississippi basin, most notably in Indiana, Illinois, Iowa and south-
eastern Minnesota, the drift sheet comprises in many places, and some-
times wellnigh in every well of whole townships, a horizon marked by
prostrate trunks of trees, fallen leaves or rushes and grass of swamps, or
occasionally by layers of peat, above and beneath which the sections pass
through till. In different districts the forest beds differ in their relation-
ship to the terminal moraines, so that they appear to represent more
than one stage of ice advance after at least a considerable retreat. Per-

*Am. Naturalist, vol. xxii, pp. 589-598 and 705-713, July and August, 1888. Am. Geologist, vol. viii,
pp. 383, 384, December, 1891.
|Am. Geologist, vol. x, pp. 339-302, December, 1892.

202 VV. UPIIAM — PLEISTOCENE AND PRESENT ICE-SHEETS.

haps the most extensive and continuously preserved forest bed is that
described by McGee in northeastern Iowa, where he believes that it bears
testimony of a very long interglacial epoch, much exceeding the time
since the end of the Glacial period* But the drift-covered and forest-
clad borders of the Malaspina glacier show that this and other vegetal
deposits between beds of till might be formed by oscillations of the ice-
front, sometimes probably readvancing 100 or 200 miles, but in other
cases perhaps only a few miles, as may often have accompanied the for-
mation of terminal moraines.

The Ice Age viewed as a continuous and geologically brief

Period.

General Consideration of the Question. — This comparison of the ice-sheets
of present and past times seems to me best accordant with a reference of
all our glacial drift to a single continuous epoch of glaciation, which,
though occupying probably 10,000 years or perhaps twice or thrice that
time, was yet brief in comparison with the duration of most, other recog-
nized geologic epochs. The outflow of the upper part of the Pleistocene
ice-sheets probably exceeded the currents of narrow alpine glaciers, but
was less than the advance of broad and deep polar glaciers which end
in the sea. For the journey of Pleistocene bowlders 1,000 miles in the
ice-sheet, somewhat less than 3,000 years would be required if the average
of the glacial currents was five feet per day. The amount of the glacial
erosion and of the drift, when compared with the erosion by the Muir
glacier, imply a short rather than a long duration of the Ice age. This
conclusion is further affirmed by the continuance of the same species of
the marine molluscan faunas from the beginning of the Glacial period
to its end and to the present day.

In the light of these considerations, therefore, we are led to question
whether the generally accepted doctrine of duality or plurality of Pleisto-
cene epochs of glaciation, with long interglacial epochs, rests on a secure
basis. Under the stimulus of Dr James Croll's brilliant theory referring
the Ice age to astronomic causes, many European and American glacial-
ists have interpreted forest beds and other fossiliferous beds intercalated
between deposits of till as good evidence of long, mild epochs dividing
successive times of glaciation; but the partially forest-covered Malaspina
ice-sheet indicates, as I believe, that these beds record only temporary
oscillations of the ice boundary, not necessarily nor probably occupying
any long time. Through reliance on such evidence in Minnesota and

* " The Pleistocene History of Northeastern Iowa," in the Eleventh Annual Report of the U. S,
Geol. Survey for 1889-90.

HYPOTHETIC CONTINENTAL OSCILLATIONS. 203

adjacent areas, I was led thirteen years ago to the belief that the Ice age
comprised two or more glacial epochs ; but within the past year I have
been gradually returning to the opinion which I previously held while
engaged with Professor C. H. Hitchcock on the New Hampshire geolog-
ical survey, that the Pleistocene glaciation was essentially a unit.*

Other evidences which have been regarded by Chamberlin, Salisbury,
and McGee, as indicative of a long interglacial epoch, drawn from the
Pleistocene erosion of the Mississippi river, the Ohio and its tributaries,
the Susquehanna and other rivers of the Atlantic slope, appear to me to
admit a different interpretation. As I see the late Pliocene and Pleisto-
cene history of this region, a great uplift of the continental plateau closed
the Tertiary era and ushered in the Quaternary. During a long time
the land stood at a high altitude, and in the earlier part of this time the
Lafayette gravel and sand beds were deposited by the rivers eroding the
mountain and highland portions of their basins and spreading these beds
in their larger valleys and on the coastal plain ; but before the elevation
attained its maximum, causing the Pleistocene ice accumulation, the
streams, no longer overloaded in proportion to their steeper descent, had
eroded large portions of the Lafayette formation. By the ice weight the
earth's crust at last was depressed, so that when the ice-sheet in the Mis-
sissippi valley reached its farthest limit it was bordered by a shallow
lake, into which the fine silt of the glacial streams was carried and de-
posited as loess, upon which higher portions of the loess were afterward
brought by river floods. According to this view, the glacial period there
appears to me to have been continuous, with retreats and reJidvances of
the ice-front, but without division by long interglacial epochs. This
opinion, however, is put forth in no criticising or dogmatic spirit, but
with a sense of my obligation to present the results of my studies, in
which I am surely as liable to err as others, for the discovery of the
Pleistocene history of our continent.

Probable Synchronism of Glaciation in North America and Europe. — The
glacial drift of Europe also seems to me, after reading and pondering
Professor James Geikie's recent very able paper arguing for five glacial
epochs there.f to be more probably referable to one epoch of continuous
but fluctuating glaciation, which appears, by a comparison of the Post-
glacial oscillations of the Scandinavian peninsula and of our northeastern
Atlantic coast, to have been at least approximately synchronous with
the Glacial period in America.^ On both continents it has been com-

*For arguments sustaining this view, see Professor G. F. Wright's paper, "Unity of the Glacial
Epoch," Am. Jour. Sei., Ill, vol. xliv, pp. 351-373, November, 1892.

f'On the Glacial Succession in Europe," Trans. Roy. Soc. Edinb., vol. xxxvii, pp. 127-140, with
map, May, 1892.

| Bull. Geol. Soc. Am., vol. iii, 1892, pp. 508-511.

204 W. UPHAM — PLEISTOCENE AND PRESENT ICE-SHEETS.

puted, from various means of measurement and estimate, that the ice-
sheets were finally melted away some 6,000 to 10,000 years ago.

Relation of the Ice Age to human and geologic History. — In Europe Pro-
fessor Geikie has shown that men had reached the neolithic stage of their
development before the ice-sheet of Denmark and Scandinavia vanished ;
and similarly in California neolithic implements, probably contempora-
neous with the Ice age, are found in gravels under the lava of Table
mountain. Other discoveries of stone implements have been made by
Dr Abbott and Professors Putnam and Shaler in the late glacial gravels
of Trenton, New Jersey ; by Mr J. B. Tyrrell, of the Canadian Geological
Survey, in a beach of the glacial lake Agassiz ; and by Mr McGee in the
sediment of the last great flood of the Pleistocene lake Lahoutan.

The accumulation of the Pleistocene ice-sheets took place at or near
the beginning of man's existence, but was close to the present page in
the very long record of geology. The preglacial uplifting of the land
apparently occupied a far longer time than its glaciation, but both may
be well referred, as by Hilgard and Spencer, to the Quaternary era, which
also, according to Dana and Sir Archibald Geikie, should be considered
as extending to the present time. With this definition, the Quaternary
era may comprise 100,000 years, more or less. Judging from the com-
parative changes of marine molluscan faunas, the Tertiary era Avas prob-
ably twenty to forty times as long, comprising, therefore, some two to
four million years ; and according to Professor Dana's time ratios of this
and the earlier eras, the whole of the history of the earth's fossiliferous
rocks may be somewhere between thirty and sixty million years. This
estimate lies between that given for the earth's age from physical data
many years ago by Sir William Thomson (now Lord Kelvin), namely,
100,000,000 years, and that recently deduced by Mr Clarence King from
similar but more detailed investigations, which is 24,000,000 years.

BULL GEOL. SOC. AM.

VOL. 4. 1892. PL. 4 .

MAP OF NORTHWESTERN CALIFORNIA AND SOUTHWESTERN OREGON

Scale

• c

32 MILES

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA
VOL. 4, PP. 205-224, PL. 4 APRIL 14, 1893

( RETACEOUS AND EARLY TERTIARY OF NORTHERN CALI-
FORNIA AND OREGON*

BY J. S. DILLER

{Read before the Society December SO, 1803)

CONTENTS

Page

Cretaceous 205

The Areas and Problems investigated 20o

Relation of the Chico and Wallala Beds 207

Relation of the Chico and Horsetown Beds 207

Relation of the Horsetown and Knoxville Beds 211

Distribution and Composition of the Shasta-Chico Series 213

Tertiary 218

Pre-Cretaceous Elevation of the Klamath Mountains and Sierra Nevada 220

Inter-Cretaceous-Tertiary Upheaval of the Klamath Mountains 222

I Ii'sunu' and Conclusions 221}

Cretaceous.

The Areas and Problems investigated. — In northwestern California and
southwestern Oregon, where the Sierra Nevada, Cascade and Coast ranges
meet, there is a plexus of mountains which may for convenience be
called the Klamath mountain group. The Klamath mountains extend
from the fortieth to near the forty-fourth parallel, and include the Yallo
Bally, Bully Choop, South Fork, Trinity, McCloud, Scott and Salmon
mountains of California, and the Siskiyou, Rogue river, and perhaps
others in Oregon. The outline of the Klamath mountain group is indi-
cated on the accompanying map by a heavy broken line. The map
(plate 4) contains nearly all the localities mentioned in this paper.

* Printed by permission of the Director of the U. S. Geological Survey.

♦This paper is a sequel to a memoir on the geology of the Taylorville region of California, pub-
lished in Bull. Geol. Soo. Am., vol. 3, pp. 369-394 Both are accompanied by paleontologic papers ;
the first by Professor Hyatt, on the "Jura and Trias at Taylorville, California" (vol. :;. pp. 395-412),
and this one by Mr Stanton's brochure "On the Faunas of the Shasta and Chico Formal ions," which
immediately follows.

XXXl-Bur.r,. Geol. Soo. Am., Vol. 4, 1892. (205)

20G

J. S. DILLEE — GEOLOGY OF CALIFORNIA AND OKKGON.

In his excellent correlation paper on the Cretaceous,* Dr C. A. White
has given a bibliography and concise review of the work already done
on the rocks of that system in the Pacific border region from California
to Alaska, The present state of knowledge, so far as California is con-
cerned, may be most clearly expressed by the following tabular view,
which I copy from Dr White : f

Eocene

Chico-Tejon scries

Upper

Cretaceous

Probable place of the Wallala formation

Lower
Cretaceous

Shasta formation

Jurassic

He considers the Chico-Tejon to be the upper portion of the upper
Cretaceous, and that it continues upward into the Eocene. The Shasta
formation, which is composed of the Horsetown and Knoxville beds, is
confined wholly to the lower Cretaceous. There is supposed to have
been a long time interval X between the deposition of the Shasta and
the Chico-Tejon, and the final portion of this interval is supposed to be
represented by the Wallala formation.

My first object in this paper is to adduce evidence in support of the
following propositions :

1. The Cretaceous strata of northern California and Oregon, embracing
the Chico, Horsetown and Knoxville beds, are an essentially conformable
and continuous series of sediments, formed without distinct interruption.

2. These strata were deposited while the region was gradually sub-
siding and the sea was transgressing northern California and Oregon.

* Bulletin 82, I". S. Geological Survey, 1891.

t Ibid., p. 241.

t [bid., pp. 189, L90.

OBJECT OF THE MEMOIR. 207

This subsidence continued until the sea reached the western base of the
Sierra Nevada and all or nearly all that part of California north, north-
west and west of Lassen peak, and almost the whole of Oregon was
beneath its waters.

Relation of the Chlco and Wallala Beds. — The Wallala group of Becker
and White, exposed at Wallala, Mendocino county, California, and Todos
Santos bay of Lower California, has furnished a fauna containing only
ten reported species. The characteristic fossil of this formation, Coral-
liocharna orcutti, has since been discovered at San Diego, California, and
has been studied in the field by Dr W. H. Dall, who informs me that in
the same conformable series of strata with the Wallala fauna he found
Chico fossils. There is such an intermingling of Wallala and Chico
forms that it is not practicable to separate the Wallala and Chico beds.
It is the opinion of Dr Dall, which I am permitted to announce, that
the Wallala formation may properly be regarded as a phase of the Chico.

In a collection of fossils made in 1888 at Stinking canyon, seven miles
southeast of Stillwater post-office, Shasta county, California, there are
three fragments, which were then supposed by the writer to be coral. Mr
Stanton has examined these specimens and recognizes them as either
Rudistse or Chamidre. The structure is very well marked, but the frag-
ments are not large enough to give more than the structure. It is so
characteristic a feature of these families that there can be little doubt as
to its identity. Furthermore, as Coralllochama orcutti is the only species
yet found in the Cretaceous of the Pacific states that has the peculiar
cellular shell structure, it is probable that the fragments in question are
of that species. This view of the case is corroborated by the fact that
Axinea veatchil is one of the most common shells of the Chico beds of that
region, and Dr Dall reports the same species, as well as Baculltes chlco-
ensis, at San Diego. It is evident, therefore, that the Wallala beds are
part of the Chico and require no further special consideration.

Relation of the Chlco and Horsetown Beds. — Both of the formations are
well exposed in Tehama and Shasta counties, California, along the west-
ern side of the Sacramento valley. In 1888 and 1889 nine sections were
examined and two measured by Mr J. Stanley-Brown and the writer*
across the Cretaceous belt between Paskenta and Redding.

The general strike of all the Cretaceous rocks in this belt is approxi-
mately north and south, and their dip is to the eastward, away from the
older rocks of the Yallo Bally mountains of the Klamath group. Sev-
eral small faults and folds, beside numerous irregularities in the dip and
strike of the strata at other points, were observed, but the irregularities
Avere always slight and of limited extent, and occur irregularly distributed

* Am. Jour. Sci., vol. xl.Dec, 1800, p. 470.

208 J. S. DILLER — GEOLOGY 01 CALIFORNIA AND OREGON.

throughout tin; whole series. No definite discordance; could be made
out anywhere within the sections, and the slight irregularities could not
he identified in any two sections at the same horizon. There is good
reason, therefore, for believing that these irregularities are only local.
They are believed to be simply those of original continuous deposition
coupled with others that naturally arise in the deformation of a great
thickness of shales conformably interstratified with a much smaller pro-
portion of relatively thin conglomerates and sandstones.

The conclusion derived at that time from a study of the stratigraphy
alone was that the Cretaceous formations from the base of the Knoxville
through the Horsetown to the top of the Chico form a continuous scries
of sediments, the deposition of which took place without a marked in-
terruption of any kind. At the same time it was fully recognized that
even absolute conformity * does not necessarily indicate uninterrupted
sedimentation, and that faunal continuity is essential to complete the
demonstration. Furthermore, Dr Becker reports an unconformity be-
tween the Chico and Shasta groups at several points on the ('oast range,
and considers it of great importance.! Mr H. W. Turner states | that
sections north of mount Diablo apparently show continuous deposition
• from the Neocomian to the Pliocene, inclusive. Nevertheless, from his
own observation, there and elsewhere, together with those of Mr Becker
and Dr White, he regards it as practically certain that there is an un-
conformity between the Chico and Knoxville beds.

In none of the cases noted above have the authors been advantagously
situated to compare the faunal relations of the two groups. This 1 shall
now proceed to briefly consider.

During the seasons mentioned many Cretaceous fossils were collected
from seventy-nine different localities in California and Oregon. Since
that time the collections have been greatly augmented from other local-
ities in Oregon by Mr W. Q. Brown, and in California by James Storrs
and the writer.

The fossils were all determined by Mr T. W. Stanton || under the su-
pervision of Dr C. A. White. They kindly furnished notes on the age
of the fossils in each case, distinguishing only between the Shasta and
the Chico-Tejon. In some case's, of course, the age could be stated; in
others it was doubtful, but in most cases it, was given without reservation.

When ari attempt was made to represent these determinations on a
map and draw the line between the Chico-Tejon and the Shasta, a serious

♦ McConnel describes the Cretaceous as perfectly conformable on the lower Carboniferous or
upper Devonian. Geol. Survey of Canada, Annual Report, 1886, pari D, p. 17.
t Bulletin 19, U. S. Geol. Survey, 1885, p. 12; U. S. Geol. Survey Monograph xiii, 1888, p. 1S8.
1 Bull. Geol. Soc. Am., vol. 2, pp. 399-401.
|| Recently Mr Stanton has carefully revised his earlier determinations.

THE CHICO-SHASTA FAUNA.

209

difficulty was encountered, due to the intermingling of the localities.
Chico fossils were found in the vicinity of Ono, on the North fork of
Cottonwood creek, and elsewhere, close to the base of the Horsetown
beds. Their presence in such positions, associated with well recognized
Shasta fossils, cannot be satisfactorily explained by attributing it to the
deformation of the strata, in which they are contained.

A review of the literature, including notes on recent collections con-
cerning the faunas of the Chico and Shasta formations, respectively, in
northern California, shows that these faunas are much more closely re-
lated than formerly supposed.

Gabb reports* that Ammonites bates hi, Gabb, A. remondii, Gabb, and
Ancyloceras (?) lineatus, Gabb, have been found in both the Chico and the
Shasta groups. Dr. White f adds, with some doubt, Ammonites stoliczkan us,
Gabb. To this small list may now be added the following species :

Actasonina pupoides, Gabb.
Amauropsis oviformis (?)
Ammonites hoffmanni (?) il
Area breiveriana,
0 1 1 rlium transluc I dam,
Cordiera mitrseformis (?) "
H< (.mites vancouverensis,
Mcekia radiata,

" sella,
Pecten opcrculiformis, u
Ringicula varia,
Straparollus paucivolus (?) "
Trigonia evansana, Meek.

" tryoniana, Gabb.

Trigonia leana,

" equicostata,
Pa nopsea concentr let i ,
Cuculsea truncata,
Cardium annulatv. m,
Corbula traskii,
Mytilus quadratics,
Leda translucida,
Mcekia navis,
Tellina mattheivsonii,
Chione varians
Mactra ashb urneri,
Tellina hoffmanniana,

Gabb.

Besides the twenty-five species definitely determined there are six
whose identification is doubtful. Of the latter it may be said that, if not
identical with the species named, they are most likely closely related.
If these identifications are correct there are thirty-one species which con-
tinue from the Horsetown beds over into the Chico. Furthermore, in
addition to these there are numerous genera common to both series, but
not represented, so far as yet known, by determinable common species.

The intermingling of Shasta and Chico fossils in the same beds may
he seen best at Horsetown and Texas springs, J where those noted in the

*Geol. Survey of California: Paleontology, vol. ii, 18—, pp. 211-213.

t Bulletin 15, U. S. Geol. Survey, p 19.

| Texas springs are on the northern side of Clear creek, three mil'-s below Horsetown, Shasta
county, California. At these two localities there are not more than 100 feet of Cretaceous rocks
exposed, resting directly, with marked unconformity, on fossiliferous Jura-Trias and older rock?.

210

J. S. DILLEK — GEOLOGY OF CALIFORNIA AND OREGON.

following lists have been collected recently for the writer by James Storrs.

To distinguish the Shasta and Chico species, as indicated by Mr Stan-
ton in these lists, the former have been marked with an asterisk (*) and
the latter with an obelisk (f).

FOSSILS FROM HORSETOWN.

^Ammonites hoffmanni, Gabb.
^Ammonites breweri, "

*Deptychoceras Isevis, (i

. I ncyloceras (?) lineatus, "
*l>Y/< in a i Irs inijircxxii.s, "

Liotium punctatum, "

Cumlia, sp. undet., "

*Lunatia ((cell ana, "

fRingicula carta, "

fPanopsea concentrica, "

fCuculaea truncata, "

fArca breweriana, ''

f 7 '/ • igo nia ; eq 1 1 wostata , ' '

Trigonia, related to evansana,%
fPecten operculiformis, Gabb.
f Cardinal (Lmvicardium) annula-

tum, Gabb.
fCorbula traskii.
fMytilus quadratics, Gabb (?)
fLeda translucida, "
*Pleuromya laevigata, Whiteaves.
Rhynchonella, sp. undet.
~f Nemo don vancouverensis, Meek.

FOSSILS FROM TEXAS SPRINGS.*

^Ammonites hoffmanni, Gabl).
* Ammonites breweri, "

Action rina californica, "
Gyrodes, sp. undet.
*Belemnites impressus, Gabb.
Liocium punctatum, "

Fusus aratus, "

*Lunatia avellana, ''

Scalaria albensis (_?). D'Orb.
*Ringinella polita, Gabb (?).
*Anisomyon meekii, "
t^4?ra breweriana, "

f Trigonia sequ icostata, "
Trigonia related to evansana, J
fPecten operculiformis, Gabb.
'[Trigonia leana, "

fCorbula traskii.
"fTellina hoffmanni, Gabb.
f Mactra ashburneri, "
"\Chinone varians, "
Rhynchonella, sp. undet.
^Tellina mathewsonii, Gabb.
fMeekia radiata, "

~\Meckia navis, "

•jjfggfcta «//^, "

Mytilus lanceolatus, Sowerby (?).
jPanapn a concentrica, Gabb.

Concerning this collection Mr Stanton, in his report dated December

17, 1892, says :

" It is evident that all the fossils in both these lists belong to one fauna, and
probably to a very limited zone, and the)' will he so considered in making com-
parisons with described faunas.

| Probably not described.

INTERGRADATION OF THE SHASTA AND CHICO. 211

" This collection leaves no room for doubt that the faunas of the Shasta and Chico
groups are so intimately blended that they cannot be separated. Horsetown is a
well known Shasta locality, from which the types of some of Gabb's Shasta species
were collected, yet in this small collection, containing twenty-one species from this
place, ten species belong to the Chico fauna as described by Mr Gabb. Combin-
ing the collections from these localities, there are thirty-six species enumerated, of
which ten have been described as coming from the Shasta group, eighteen from the
Chico group, and eight are doubtful or undecided." *

So far as I have been able to learn, about seventy species and a dozen
genera not represented by determinable species have already been rec-
ognized in the Shasta series of California. Of these fossils certainly more
than one-fourth, and probably nearly one-half, continue upward into
the Chico beds, and clearly indicate that the Horsetown and Chico beds
are much more closely related than has been supposed. f

When we take into consideration, at the same time, both the strati-
graphic and faunal evidence, there can be no doubt that the Horsetown
and Chico beds were formed in one period of continuous sedimenta-
tion.

Relation of the Horsetown and Knoxville Beds. — In Tehama county, Cal-
ifornia, where the contact between the Horsetown and Knoxville beds
is well exposed, their relation can be studied to great advantage. Along
Elder creek, just north of the fortieth parallel, at the eastern base of
Yallo Bally, the unaltered fossiliferous Cretaceous strata have an appar-
ent thickness of nearly 30,000 feet.J The whole series, including the
Chico and Shasta groups, dips eastward away from the Coast range with
remarkable uniformity and appears to he one continuous series of sedi-
ments from top to bottom without a perceptible interruption. In the
lower 19,900 feet its only fossil found is Aucella. These sedimentary rocks;
the Knoxville beds, are limited below by serpentines resulting from the
alteration of peridotitic eruptives such as form a considerable portion of
the Klamath mountains and Coast range. In the upper 3,900 feet of the
Elder creek section Chico fossils occur abundantly, while in the inter-
mediate 6,100 feet Horsetown fossils have been found. The latter are
best exposed in the Eald hills between Paskenta and Lowrey's, where
Aucella occurs abundantly in the basal portion, associated with Ammon-
ites batesii, Trask ; A. ramosus, Meek.; A. traskii (?), Gabb; Ancyloceras
percostatus, Gabb ; Rhynchonella, n. sp. ; Siliqua, sp. undet. Although
these fossils were not actually seen together with Aucella in the same
rock exposure, yet they were seen so near together throughout a great

* See also Mr Stanton's paper which immediately follows, p. '22.',, et seq.

fjt is important to rememlier in this connection that the collections have been made almost
wholly by geologists while studying the stratigraphy, and not by paleontologists who were en-
deavoring to determine the relations of the faunas.

J; Am. Jour. Sci., 3d ser., vol. xl, 1890, p. 47<>. See also Bull. Geol. Soc. Am., vol. 2, p. '_'n7.

212 J. S. DILLER — GEOLOGY OF CALIFORNIA AND OREGON.

thickness of conformable shales and sandstones that the writer regarded
them as not only contemporaneous but intermingled and belonging to
the same fauna. On Elder creek, therefore, the evidence clearly indi-
cates that the Horsetown beds are younger than the Knoxville, and
that between them there is a stratigraphic and fauna] continuity.

Mr Becker and the writer* claimed that at Riddles, Oregon, AueeUa is
associated with ammonites and other forms of Horsetown age. The
writer visited Riddles four times, and, in company with Mr Will Q.
Brown, examined nearly all of the fossiliferous rocks of that region, but
has never been able to obtain AueeUa and Horsetown fossils from exactly
the same exposure. The rocks containing these fossils, however, are so
intermingled and related to each other structurally that there can be no
doubt that the fossils all belong to the same fauna. The valley of Cow
creek is eroded out of a more or less modified synclinal of Cretaceous
rocks. The older Aucella-henrmg strata are upon the sides. The strata
in which Horsetown forms are most abundant occur near the middle of
the valley, in the immediate vicinity of Riddles, where Aucella also
occurs. The whole set of strata appears to be conformable.

The following forms have been identified by Messrs White and Stan-
ton in the collections made by Messrs Becker, Brown and the writer
near Riddles, Oregon :

Aucella concentrica, Fisher. Pleuromya laevigata, Whiteaves.

Amninriilrs tra*kii, Gabb. Pecten operculiformis, Gabb.
" batcsii, " " Californicus, "

" brcweri, " Cardita translucidum, "

Belemnites impressus, " Area breweriana, "

In northern California the writer has found Ammonites traskii and A.
batcsii in the lower half of the Horsetown beds only, A. brcweri in the
upper half of the Horsetown beds, Pleuromya laevigata, Pecten operculi-
f or mis and Belemnites throughout the Horsetown beds, and the last two,
Cardita translucidum and Area breweriana, in both Shasta and Chico
beds.f

* Bull. Geol. Soc. Am., vol. 2, pp. 201-207.

fMr Will Q. Brown, who, under the writer's supervision, mapped a large part of the Cretai us

rooks in Jackson and Douglas counties in Oregon, has recently made an important contribution
of new evidence. A collection which he generously made and transmitted at his own expense shows
Aucella and an Ammonitt in the same hand specimen, so there can be no doubt concerning their
association. Professor Hyatt has examined the specimen, and reports. December, 1892, that " the
Ammonites could by its external whorls be referred to either of the two groups Cosmoceras of the
upper Jura or Hoplitcs of the Cretaceous. By digging into the specimen enough of one of the
inner whorls was exposed to indicate that the A mmonites is one of the Cryptoa ras groups of HopliU s,

and probably a true Cretacic species." Professor Hyatt adds that, as he has not yet l d able to

find any species of this group with an aperture, his opinion stated above is only pnn isional, but the
evidence so far goes to show that one of the forms of Aucella occurs with a Cretaceous Ammonites.
The Ammonites, however, is very distinct from anything yet discovered in the Horsetow a beds else
where, it occurs in the basal portion of the beds which occupy Cow creek valley.

INTERGRADATION OP THE KNOXVILLE AND HORSETOWN. 213

From both stratigraphic and paleontologic points of view, therefore,
the evidence strongly supports the opinion that the Knoxville and Horse-
town beds in northern California and Oregon are a successive and con-
tinuous conformable series of sediments laid down without perceptible
interruption.

Since the Knoxville beds pass upward without interruption into the
Horsetown beds and the latter in the same way grade into the Chico
beds, we arrive at the conclusion contained in the first proposition of the
thesis, namely :

The Cretaceous strata of northern California and Oregon, embracing
the Chico, Horsetown and Knoxville beds, or, in other words, the Chico
and Shasta beds, are an essentially conformable and continuous series of
sediments formed without a distinct interruption. For this series Mr
Stanton and 1 have agreed to use the name Shasta-Chico series.

Distribution and Composition of the Shasta-Chico Series. — The distribution
of the Knoxville beds in the Coast range south of the fortieth parallel
is described, so far as yet known, chiefly by Becker, Turner and Fair-
banks in a number of papers* They are well developed on Elder creek.
If we place the upper limit so far up as to include all the .l>"v//a-bearing
strata, they extend, according to Fairbanks, as far northward as Cold fork.
Tehama county, near the Shasta county line. At that point the present
writer has observed the Shasta group to rest unconformably upon the
metamorphic rocks, and the unconformity is conspicuous.

The Horsetown beds have been definitely recognized only a few miles
south of the fortieth parallel, but in the opposite direction they have
been traced a long distance. From Elder creek, where they conformably
overlie the Knoxville beds, they extend northward far beyond the latter,
unconformably overlapping the older metamorphic rocks, to Horsetown
and Texas springs, nearly as tar north as Redding.

This overlapping is well shown in the Horsetown beds themselves.
Ammonite* ramosus and A. batesii were found on the South fork of Elder
creek near Aucella and in conformable strata far beneath the latest strata,
containing Aucella. The writer has not found these ammonites to extend
above the middle portion of the Horsetown beds. In the vicinity of Ono,
on the North fork of Cottonwood, they are common near the uncon-
formable contact between the Cretaceous and metamorphic rocks, but
have not yet been discovered as far north so Horsetown, where only the
upper members of the Horsetown beds occur. Ammonites hoffmanni and
A. breweri, which occur at Horsetown and farther southward just above

*G. F. Becker: Bulletin 19, U. S. Geol. Survey; U. S. Geol. Survey Monograph xiii: and Hull.
Geol. Soc. Am., vol. 2, pp. 201-208.

W. II. Turner • Bull. Geol. Soe. Am., vol. 2, pp. 399-401.

H.W.Fairbanks: American Geologist, vol. ix, p. 159, March, 1892 ; ib., vol. xi, p. 69, February, 1893.

XXXII— Bum.. Geol. Soc. Am., Vol. 4, 1892.

214 J. S. DILLER GEOLOGY OF CALIFORNIA AND OREGON.

the latest A. ramorus and A. batesii, belong to the upper half of the Horse-
town beds and extend much farther northward in its series, overlapping
the older raetamorphic rocks.

From the North fork of Cottonwood creek the Horsctown beds extend
far westward, crossing the range between Yallo Bally and Bully Choop
mountains along the Hay fork road, and an isolated fossiliferous area of
them nearly five square miles in extent occupies Bedding creek basin in
Trinity county, at the northwestern base of the Bully Choop mountains.
Everywhere beyond the limit of the Knoxville beds the Horsctown beds
rest, with a marked unconformity, directly on the metamorphic rocks.

The Chico beds have a wide distribution in southern California, and
to the northward underlie the Sacramento valley, with outcrops on
both sides. At Elder creek, on the western side of the valley, the Chico
beds rest conformably on the Horsetown beds. They extend north-
ward, holding the same relation to the Horsetown beds until near Bed-
ding, where the Horsetown beds run out and the Chico beds rest uncon-
form ably on the metamorphic rocks. This unconformable contact be-
tween the Chico beds and older metamorphic rocks, including at least
Carboniferous, Triassic and Jurassic strata, has been traced around the
northern end of the Sacramento valley, and, by way of the Great bend of
Pit river, Mount Shasta, Henley and Ashland, farinto ( Oregon. There is
good reason for believing that the Chico beds which extend beneath the
lavas of the southern portion of the Cascade range connect with those
recognized on Crooked river, Oregon*

At a number of places in the Klamath mountains there are remnants
of Cretaceous rocks in which these mountains were once enveloped, but
this covering has nearly disappeared by erosion. To enter into the de-
tails of their distribution Avould lead beyond the proper limits of this
paper. Let it be sufficient to say that their distribution shows that the
Klamath mountain region was almost, if not wholly, beneath the sea
during the closing days of the Cretaceous. f

On Elder creek, in Tehama county, California, the Chico, Horsetown
and Knoxville beds are all present. The Knoxville beds extend from
this place only a few miles to the northward ; the Horsetown beds ex-
tend beyond them in that direction at least 25 miles, while the Chico
beds stretch still further in the same direction far into Oregon. The Cre-
taceous section thins out rapidly in the same direction by the successive
dropping out of the earlier beds. On Elder creek the Cretaceous is ap-
parently over 20,000 feet thick, at Ono 8,800 feet, and further northeast-

* Bulletin 33, U. S. Geol. Survey p. 19.

fSince the paper on fche geology of Lassen peak was written i Eighth Ann. Rept. ('. s. Geol. Sur-
vey, p. 411,412) the subsidence has i o found much greater Hum was a! firs! supposed, so that the

Cretaceous island may have wholly disappeared near the end oi thai period.

TRANSGRESSION OF THE CRETACEOUS SEA. 215

ward still less. In none of the sections, however, has the exact top of
the Cretaceous been seen. Since these beds are all marine and form one
continuous series of sediments, it follows, from their distribution, that
during their period of deposition the sea was transgressing what is now
the northern portion of California.

That the sea was transgressing during the Cretaceous is clearly shown
also by the character of the Cretaceous sediments. Before the deposition
of the Shasta group the Klamath mountains, composed of Jurassic, Tri-
assic and Paleozoic rocks, more or less metamorphosed, had been dry
land, exposed to weathering for a sufficiently long time to allow the sec-
ular disintegration of a mass of surface rock to form the residuary
deposits which have become the sediments of the Shasta group. In
some cases the deposits of the Shasta group bearing fossils rest upon
the residuary deposits and rotten rock from which they were derived,
and the line of contact is not easily recognized. This is the case on the
southeastern border of the Klamath mountains, in Shasta county, Cali-
fornia, between Ono and Igo, where micaceous sandstone at the base of
the Shasta group so closely resembles the rotten diorite on which it rests
that until the presence or absence of fossils is determined one is in doubt
which rock he may be examining*

Near at hand, too, by the present streams, there are coarse shore con-
glomerates, including the gravels of the Cretaceous streams which flowed
down from the Klamath mountains on the northwest into the ancient
bay of the Sacramento valley, and one is surprised to find some evidence
that the valleys of the embouching streams of early Cretaceous times
are still occupied by streams. This may be true to a very limited
extent, but it is noticeable in the upper tributaries of the North Fork of
Cottonwood creek near Ono.

From this point the Cretaceous rocks extend westward, and the later
members of the series lap up over the Yallo Bally and Bully Choop
ridge, the main divide of the Klamath mountains, crossing to the' west-
ern slope, where they appear well characterized by fossils in Redding
creek basin of Trinity county. In all cases the Cretaceous sediments
immediately in contact with the metamorphic rocks are of local origin.
When they are coarse the contact is plain and the unconformity so well
pronounced as to be beyond question, but where the sediments are fine
there may appear to be a gradual transition from the older metamorphic
rocks to the Cretaceous. For reasons already given, however, I am hilly
convinced that in northern California and Oregon it is chiefly apparent
and rarely if ever real.f It would be expected that the unconformable

*See observations by Dr Dawson in Geol. Survey of Canada, Rept. of Progress, 1877-78, p. luG B.
He describes the same sort of phenomena at the base of the Cretaceous on the Skagit

t Incases where the Cretaceous strata have been metamorphosed a transition from the unaltered
to the altered portions without an intervening unconformity would be expected.

216 J. S. DILLER — GEOLOGY OF CALIFORNIA AND OREGON.

contact immediately underneath the Knoxville beds would be Less con-
spicuous than that between the Horsetown beds and the metamorphic
rocks or between the Chico and the metamorphics. This would follow
from the fact that the Knoxville beds, having been deeply buried by
later sediments, were subjected to more intense metamorphic action,
which tends to render the original contact less evident.

In Siskiyou county, California, upon the eastern slope of the Klamath
(Scott) mountains, adjoining Shasta valley, there are a number of impor-
tant exposures of Cretaceous rocks. Dr D. Ream, of Yreka, kindly fur-
nished me a section of the rocks penetrated by Mr King's well at the salt
works in Shasta valley, where over 500 feet of fossiliferous sandstonewas
observed beneath the lavas of Shasta valley. The same rocks are exposed
at the surface near Yreka and on Willow creek, where they contain
Chico fossils. On the edge of Shasta valley the Cretaceous strata dip
to the eastward and lap up over the lower slopes of the Klamath (Scott)
mountains, which lie upon its western border. The tilting evidently
occurred at the time the Klamath mountains were upheaved, and the
unconformably overlapping Cretaceous strata have since been nearly all
eroded. A few conspicuous remnants, however, are still there to tell the
tale. The best of these are at Cave rock, three miles north of Gazelle,
and near the summit on the road from Yreka to Fort Jones. The last
is at an elevation of 2,000 feet above Shasta valley and over 5,000 feet
above the sea. The mass is about 400 feet in thickness, and the conglom-
erate at its base is composed chiefly of white quartz and unassorted angu-
lar fragments of schistose rocks like those in place near by. Although
fossils were not found at either of these localities, there can be scarcely a
doubt that they represent the overlapping Cretaceous strata from the
foot of the same slope.

In Douglas county, Oregon, along Olalla creek, slates have been found
containing . I uct lla alone, and the rocks are considerably metamorphosed.
At Buck mountain, a few miles further southeast and twelve miles west
of Riddles, AuceUa occurs alone in coarse, pebbly sandstone, which has
a slightly metamorphic aspect. This appearance, however, is due not
so much to actual metamorphism since deposition as to the fact that the
rock is composed chiefly of residuary material removed but a short dis-
tance from its original position: consequently its contact with the oldgr
metamorphic rocks is not sharply defined. The same is true at some
localities, but not all, about Kiddles, in the valley of Cow creek, where
both AuceUa and Horsetown fossils occur in abundance. Still further
eastward, on Grave creek, an area of Shasta beds occurs. AuceUa is
absent, and there are some Chico forms present, with thoseof the Shasta
group, so that the horizon must be near the top of thai group. These

EXTENT OF THE CRETACEOUS SEA. 217

fossiliferous strata are in part coarse conglomerates of local origin and,
according to the observations of Will Q. Brown, as well as of the writer,
are clearly unconformable to the metamorphic rocks.

Twelve miles further in an easterly direction, near Jacksonville, and
elsewhere in Jackson county, < )regon, the Chico rocks, now called Horse-
town by Mr Stanton, rest directly with a marked unconformity on the
metamorphics.

in Oregon, therefore, the evidence, although less complete, is entirely
in harmony with that of northern California, and we are led to the con-
clusion stated in the second proposition of the thesis, namely: While
the Sliasta-Chico series was being deposited the region was gradually
subsiding and the sea transgressing to the eastward in northern Cali-
fornia and Oregon. This subsidence continued until the sea reached the
western base of the Sierra Nevada, near the fortieth parallel, and all or
nearly all that part of California north, northwest and west of Lassen
peak, as well as almost the whole of Oregon, was beneath its waters.

The occurrence of the Cretaceous in Washington, excepting that on
Sucia, Orcas and Ship Jack islands, near Vancouver, lias hitherto beena
matter of considerable doubt. Its determination has been based largely
upon certain casts which were supposed to have been of Baeulites. Ac-
cording to Willis,* the Cretaceous of northwestern Washington is com-
paratively thin and rests directly on metamorphic rocks, which are pre-
( 'retaceous and probably of Paleozoic age.

While in Seattle I obtained from Mr E. W. P. Guye a well-preserved
Baculile, which Mr Stanton determined as Baeulites chicoensis. It was ob-
tained on the Snoqualmie river, three miles below the falls, and shows
the presence of the Chico at that point. The rock is unaltered and lies
between the Puget group and the metamorphics.

At the same time my attention was called to a bowlder found in Seattle ;
it is composed chiefly of Aucclhi and was in all probability transported
from the Cascade range. The rock is unaltered and closely resembles
some of the Aucella-bea,rmg rock about Kiddles.

In the collection of Professor T. Condon at the state university, Eu-
gene, Oregon, there is a large fragment of rock f containing a multitude of
robust shells of Aucella. It came from Vashon island, near Tacoma.

Dr DawsonJ reports /4Mce/Za-bearing rocks oh the Skagit north of the
international boundary. It is believed that they extend south into Wash-
ington and have furnished the bowlders referred to.

There can be no doubt that the Shasta-Chico series is represented in

*Tenth Census, vol. xv, 18SC, p. 761.

t Tliis is probably the same material that Becker and White refer to in U. S. Geol. Survey
Monograph xiii, pp. 202, 232.
X Geol. Survey ot Canada, Report of Progress, 1877-78, p. 10G B.

21S .1. S. DILLER — GEOLOGY OF CALIFORNIA AND OREGON.

the Pugel sound region, but of its extent scarcely anything is known.
Further northward, however, the same series is extensively developed in
Vancouver and Queen Charlotte islands, as well as within the interior
portion of British Columbia, where it lias been described by Dr Selwyn,
Dr Dawson, and Mr Richardson in the reports of the Canadian geologic
survey. From an extensive knowledge of the facts, Dr Dawson concludes
that in early Cretaceous times the immediately post-Triassic elevation
had been followed by a subsidence of the land, resulting in the reoccu-
pation by the open sea of a great area near the Pacific coast and north
of the fifty-fourth parallel, spreading eastward in a more or less connected
manner completely across the present position of the Cordilleras. The
Gold ranges, and probably also many other insular areas, continued to
exist as dry land. As local terrestrial conditions are recurrent through-
out a great thickness of strata, it is obvious that the subsidence was
continuous or nearly so and was followed pari passu by sedimentation.
Dr Dawson says :

"About the stage in the Cretaceous which is represented by the Dakota group,
however, a much more rapid downward movement of the laud occurred. This is
marked by the occurrence of massive conglomerates, which have been recognized
in many places in the southern part of the interior of British Columbia, as well as
westward to the Queen Charlotte islands."*

Dr Dawson calls attention to the tact that west of the axis of the
Coast ranges the area of Cretaceous sedimentation was transgressively
extending southward, the local base of the Cretaceous being found at suc-
cessively higher stages in the system in that direction, till at a time, which
is believed to have corresponded with the Laramie of the plains, the sea
invaded the Puget sound region. The invasion of the sea in British
Columbia was contemporaneous with that of northern California and
Oregon just described, and possibly also with that which carried Aueetta
around the southern end of the land barrier into Mexico.f

Tertiary.

The Tejon beds are now generally regarded as representing the earliest
Tertiary deposits of California ami Oregon. In noddle California these
beds are well represented. They are not only conformable with the( !hic( >.
lint have been considered to form, with the Chico, a continuous series of
strata, deposited without any interruption in the process of sedimenta-
tion. This is unusual, for generally a fauna! and stratigraphic break
occurs between the Cretaceous and Tertiary.

* Am. .lour. Sri., .",.1 sit., vol. xxxviii, 1880, p. 120; Transactions of the Royal So< iety of Canada,
vol. viii, sect, iv, 1S!H>, pp. 8, •>. See also S. F. Emmons, Bull. Geol. Sue. Am., vol. 1, p. 278.
fNeues Jarb. fur Min., Geol. u. Pal., ls'ju, ii bund, p. l'v:;.

DISTINCTION OF TPIE CHICO AND TE.TON. 219

Lindgren has recognized the Tejon in the Sacramento valley as far
northward as Marysville buttes * In the Coast range Whitney, on Gabb's
observation, reports the Tejon nearly as far northward as Round valley,
Mendocino county* Similar coal-bearing strata containing fossil leaves
have been observed by the present writer at Hyampome, Cox's bar and
Redding creek basin, in Humboldt and Trinity counties, but the evidence
that these strata are really Tejon is not convincing ; they are rather more
probably Miocene. With the exception of the locality at Marysville
buttes, no molluscan fossils of Tejon age have been found in northern
California, and it has generally been regarded as absent.

In Oregon, however, the case is very different. The Tejon, well char-
acterized by an abundance of marine fossils, is represented by at least
2,000 feet of strata. Professor Condon has reported it at Cape Arago by
Coos bay, and at Albany. Dr C. A. White has recognized it at Astoria,
where it has since been studied by Dr W. H. Dall. Profess* >r ( !< mdon called
my attention by letter to an excellent exposure of fossiliferous Eocene on
the South fork of the north Umpqua, where Mr Will Q. Brown and the
writer have made several collections. At least 1,000 feet of Eocene si rata
are there exposed. They contain throughout abundant shells of Cardiia
planicosta, with other fossils, and rest directly upon an irregular surface
of metamorphic rocks. From this point the Eocene beds have been
traced southwestward nearly to Coos bay, and fossils have 1 teen collected
at Cleveland, Lookingglass, Olalla and Table mountain. At the last two
localities they rest on the upturned edges of the Shasta-Chico series.
The unconformity at the base of the Tejon group in Douglas county,
Oregon, is in some cases conspicuous and in all eases well defined,
and it appears that the Shasta-Chico series was not only folded but
considerably eroded before the beginning of deposition of the Tejon in
that region.

With such a physical break, faunal continuity between the Chico and
the Tejon of Oregon could hardly be expected ; but, to test this point as
far as possible with the collections now at hand, I requested Mr Stanton
to carefully examine the collections of Tejon from Oregon and Washing-
ton for Chico species. In response Mr Stanton sent lists of all the species
collected at a number of localities, and remarks :f

" You will notice that there are a few species among them that have been re-
ported from both the Chico ami the Tejon. For example, Pholadomya namta, < '//-
lichna costata ami Turriiella chicoenm. There are also some others that closely re-
semble Chico species, but which I believe to be distinct, such as Mactra ashburneri
and DentaMum stramineum. We have the two species last named from Chico locali-
ties, and, on direct comparison with the related Tejon forms, there is no difficulty

*Geol. Survey of Cal., Fa]., vol. ii, p. xiii.
f January '.>, 1893,

»
220 J. S. DILLER — GEOLOGY OF CALIFORNIA AND OREGON.

in pointing out recognizable differences. None of the other doubtful species arc
represented in any of our collections from Chico localities.

'•It is therefore safe to say that your collections do not show any commingling
of the Chico and Tejon faunas, and I may add that, so far as I have examined them,
none of the other collections in the National Museum show such blending."'

All of the facts yet known indicate that in Oregon and northern Cali-
fornia there is a fannal and stratigraphic break between the Chico and
the Tejon.

Pre-Cretaceous Elevation of the Klamath Mountains and Sierra

Nevada.

The existence of a large land area in northwestern California and south-
western Oregon in early Cretaceous times is clearly indicated by the com-
position and distribution of the Cretaceous rocks of that region. The
geologic date of the uplift must have been considerably earlier than the
beginning of the Shasta-Chico epoch in order to allow the secular disin-
tegration of the surface rocks to furnish the Cretaceous sediments for the
invading sea.

Since the writer's paper on the geology of the Taylorville region was
published, our knowledge of the distribution of the Jura-Trias and Car-
boniferous in northern California has been considerably extended, and.
as this distribution has an important bearing on portions of this paper,
it is necessary to record it here.

A large number of fossils were collected by the writer and James Storrs
on and near Pit river by the western arm of the Great bend, and at many
places near Cedar creek and Halcombs, on the toll and stage roads be-
t ween Redding and Burney valley. The areal geologic work done at that
time is shown in the Bend and Cedar formations in the northwestern
corner of the Lassen peak atlas sheet, a preliminary edition of which
i» now in proof. The fossils were all examined by Professor A. Hyatt.
and in the descriptive text accompanying that sheet his conclusions con-
cerning the age of the rocks are stated. Both the Jurassic and Triassic
of the Taylorville region are well represented in Pit river valley and add
another strong argument, showing that the Klamath mountains of north-
western California are composed in large part of the same rocks as the
Sierra Nevada, f

Along the western side of the Sacramento valley, near the basin on
the Humboldt trail eight miles west of Pettyjohns, in Tehama county,

* Almost thirty species have been identified from the Tejon of Oregon and Washington.

t Mr Harold W. Fairbanks, who has published an article entitled "Tin- pre-Cretaceous Age of the
Metamorphic Rocks of the California (cast Range" (Am. Geologist for March, 1892, vol. ix,"pp,
153-166 : also for Feb., 1893, vol. xi. pp. 69-84), kindly call f. 1 my attention to a number of new locali-
ties in the Pit river region from which he had recently collected i'"s>il<.

DISTRIBUTION OF JURASSIC FOSSILS. 221

fossils were found in a limestone. Mr Walcott, who examined the fossils
for me, reported that only one genus, viz, Chasleles, could be identified,
and from what is known of the rocks of that region he refers the lime-
stone to the Carboniferous. This horizon had long been known fur-
ther northward, near Bass' ranch, through the investigations of Trask
and Whitney.

Pentagonal and round erinoid .stems have been discovered by James
Storrs in a limestone on Clear creek between Horsetown and Texas
Springs. Professor Hyatt regards them as Triassic and probably of the
same horizon as the Hosselkus limestone*

At Texas Springs Mr Storrs found a limestone containing a large pen-
tagonal erinoid stem, a spirifer and other brachiopods which Professor
Hyatt regards as belonging within the Jura-Trias. The older rocks,
upon which the Cretaceous strata of the western and northern borders
of the Sacramento valley at the Pit river region rest with a conspicuous
unconformity, are at least in part Jurassic, Triassic and Carboniferous
in age.

As bearing upon the general distribution of the Taylorville Jurassic, a
collection of fossils made by Professor Condon on the upper waters of
Crooked river, in the Blue mountains of Oregon, deserves mention. In
lithologic character and fossils Professor Condon's specimens appeared
to the writer to very closely resemble the Jurassic rocks of Taylorville.
Professor Condon kindly loaned the specimens to be sent to Professor
Hyatt, who confirmed this view and established another important
locality of Taylorville Jurassic

The discovery of Jurassic fossils on Pit river synchronous if not iden-
tical with that of Taylorville has thrown new light on the pre-Cretaceous
elevation of the Klamath mountains and the Sierra Nevada. Concern-
ing some of these fossils Professor Hyatt says* they " include the same
association of forms as the Mormon sandstone fauna, and, although the
specimens are not all well preserved, I have little doubt that the rocks
from which they came were synchronous with the Mormon sandstone of
Taylorville."

These Jurassic rocks were deformed and metamorphosed with the
Triassic. Carboniferous and other portions of the auriferous slates.
They are separated from the unaltered Cretaceous (Shasta-Chico series)
of that district by a conspicuous unconformity. The same unconformity
extends southwestward, by way of Bedding, Horsetown and Ono, along
the western side of the Sacramento valley, into Tehama county, Califor-
nia, and northward, by way of Yreka, Cottonwood creek and Ashland,
far into Oregon. It is evident, therefore, that a great upheaval and met-

* Letter of October 4, 1802.
XXXIII— Bull. Geol. Soc. Am., Vol. 4, 1882.

222 .!. S. DILLEK — GEOLOGY OF CALIFORNIA AND OREGON.

amorphism of the Klamath mountains and Sierra Nevada occurred soon

after the close of the Taylorville Jurassic.

How long a time interval is represented by the great unconformity
between the Taylorville Jurassic and the Shasta-Chico series is not yet
known, hut that the upheaval took place in the earlier part of the inter-
val is most probable.

The relation of the Mariposa beds to the Taylorville Jurassic, on the
one hand, and to the Shasta-Chico scries, on the other, is yet a matter of
doubt, but will soon be resolved by Mr Becker and his assistants, Messrs
Turner and Lindgren, who are now making a thorough survey of the
Gold belt of the Sierra Nevada. It is already evident from the researches
of Mr Becker and Dr White that the faunas of the Mariposa and Knox-
ville beds are closely related, and on this account the great fauna! and
stratigraphic break corresponding to the great unconformity between
Shasta-Chico series and the Taylorville Jurassic on Pit river might be
expected at the base of the Mariposa beds. That an upheaval occurred
at the close of the Jurassic of Taylorville is indicated by the distribution
of Auccllu in northern California and Oregon. Accordingly the disturb-
ance in the Mariposa beds would have to be referred* to a later epoch,
either within the Aucella-beaxing series or to the close of the Chico or
Miocene.

Inter-Cretaceous-Tertiary Upheaval of the Klamath Mountains.

The lower portion of the Shasta-Chico series is in general more dis-
turbed than the upper or Chico portion. This is due to various causes,
the principal of which is to be found in the fact that, as now exposed,
the Shasta beds are nearer the centers of disturbance than the Chico.
The Chico has been removed from the disturbed areas by erosion.

On the western side of the Sacramento valley, along Elder creek,
where the Shasta-Chico series is exposed, the whole series is tilted, but
the Shasta beds in the western portion toward the Coast range arc some-
what more disturbed than the Chico beds in the eastern portion ; yet
the difference is not great and the change so gradual through a number
of miles of well-exposed strata that we looked in vain for any break in
the stratigraphy or fauna.

The character of the strata had much to do in determining the amount
of deformation. The shales of the Shasta-Chico series are generally more
deformed than the sandstones and conglomerates of the same locality,
1 lecause less rigid. They predominate in the lower portion of the Shasta-

*See paper by Mr S. F. Kmmons "On Orographic MmvuiniN in the Roeky Mountains," Hull.
Oeol, Soc. Am., vol. 1, \>. 27'J.

EFFECT OF STRUCTURE ON DEFORMATION. 223

Chico series, and were deeply buried beneath the Chico. As a conse-
quence they were subjected to the more rigorous action of deforming
forces. The Shasta-Chico series in northern California and Oregon is
rarely vertical, and from that angle the clip ranges to nearly horizontal.
The gentlest inclinations are in the Chico on the western side and around
the northern end of the Sacramento valley, and always miles away from
the disturbed lower portions of the same series.

The geologic date of the disturbance next succeeding the pre-Cretaceous
one just referred to is well marked in Oregon, where, as already described,
the Tejon is unconformable upon the Shasta-Chico series. Near the
unconformable contact the Tejon is not folded, so that the deformation
of the Shasta-Chico series, which is conspicuous in that region, took
place before the deposition of the Tejon, or about the close of the Cre-
taceous. That this deformation was accompanied by upheaval is shown
by the absence of Tejon in northern California and part of Oregon.

This deformation and upheaval appear to have been of great extent
to the northward, for the Cretaceous sea which once covered part of
Oregon, Washington and a large portion of British Columbia was
driven westward by it, in some cases beyond the present limit of the
continent; and about this time, according to King, the Wasacht range
was uplifted *

Resume and Conclusions.

The observations of Dr W. H. Dall have shown that the Wallala beds
are a phase of the Chico and belong near the base of those beds, essen-
tially in the position assigned to them by Dr White.

The Chico and Horsetown beds, which were once supposed to be sep-
arated by a long interval, are now known to be stratigraphically and
faunally continuous, and are the result of an uninterrupted epoch of
sedimentation.

In the same way the Horsetown and Knoxville, which together form
the Shasta beds, are shown to lie stratigraphically and faunally contin-

*The date of the deformation of the Mariposa beds must yet be regarded as an open question.
If, as argued by Mr Becker, later by Mr Fairbanks, and finally by Messrs Turner and Lindgren,
who have mapped the region, the Mariposa beds are unconformably beneath tin; Chico, their
deformation would appear 1" have antedated the deposition of the Shasta-I Ihieo scries, I'm- in the
group of strata including lie- Mariposa, Knoxville, Horsetown and Chico beds the argument for
faunal and stratigraphic continuity is weakest between the Mariposa and Knoxville beds. The
faunal relation of the Mariposa and Knoxville beds, however, is so close, according to Mr Becker,
as not to admit of a great physical break hetween them. If one exists it- is possibly local and of
limited extent. This might still lie in accord with the facts observed in northern California and
< Iregon, where no break has yet been observed within the Aucelta-bearing rocks.

Numerous observers have called attention to the great mountain-forming epoch about the .lose
of the Miocene. During that revolution tic Klamath mountains and tic Sierra Nevada were
modified to a large extent. The geologic history referred to in this paper wholly precedes that
disturbance.

224 J. S. DILLEK — GEOLOGY OF CALIFORNIA AND OREGON.

uous, and it follows that the Shasta-Chico series is the result of contin-
uous sedimentation.

The distribution of the members of the Shasta-Chico series and the
composition of those in contact with the older rocks, on which they rest
unconformably, shows that during their deposition the northern parts
of California and Oregon were gradually subsiding and the sea trans-
gressing.

In Oregon the Tejon rests upon the Shasta-Chico series unconformably,
and the paleontologic evidence, so far as it goes, tends to show that there
is a faunal break in that region between the Chico and the Tejon.

At the close of the Taylorville Jurassic there was an upheaval, by
which the Klamath mountains and the northern end of the Sierra
Nevada were outlined and the land extended far northwestward into
the Pacific.

This upheaval was followed after a considerable interval by a sub-
sidence, which brought in Aucella from the northwest and inaugurated
the Shasta-Chico series.

In northern California and Oregon the subsidence continued through-
out that series, unless interrupted between the Mariposa and Knoxville
epochs, and was brought to a close by another mountain-forming
upheaval, which forced the sea far to the westward before the begin-
ning of the Tejon.

IT. S. Geological Survey,

Washington, 1). C.

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA
Vol. 4, pp. 225-240 May 20, 1893

ON THE GEOLOGY OF NATURAL GAS AND PETROLEUM IN

SOUTHWESTERN ONTARIO

BY II. P. H. BRUMELL

(Read before the Society December 29, 1892)

CONTENTS

Page

The Areas under Consideration 226

Gas-producing A rea 221 >

Oil-producing' Area 226

Authorities indicated 226

Geologic Section of the Areas 226

The geologic Formations involved 227

Detailed Description essential 227

Portage 227

Hamilton 227

Corniferous 228

Oriskany 229

Onondaga and Lower Helderherg 230

Guelph 231

Niagara 231

Clinton 232

Medina 232

Hudson River 234

Utica 234

Trenton and Black River 2:14

Geologic. Horizons in Ontario yielding I ras and Oil 235

Oil Wells in the Corniferous Limestone 235

Age and Depth 2:!.)

Annual Output of Oil 235

Chemical Composition of the Oil 236

The Corniferous petroliferous over a wide Area 236

The Medina as an ( )il-producer 231 i

Gas-hearing Horizons : Clinton, Medina and ( >thers 236

Localities indicated 236

Depth at which Gas is found 236

Records of twenty-eight Wells 237

Gas-bearing Bed of the Medina 237

XXXIV— Bull. Gj-.ui.. Soc. Am., Vol. 4, 1892. (225)

22G H. P. H. BRUMELL — GAS AND PETROLEUM IN ONTARIO.

Page

Daily Capacity of BOme of the Wells 237

( >ther Localities 238

The Clinton as a < ias producer 238

The Niagara as a < fas-producer 238

( Mlier ( las-bearing Formations L'.'is

The Onondaga as a Gas-producer 23J)

The Trenton as a < ras-producer 239

An unusual Occurrence of Gas 240

Forthcoming Publication on the Subject 240

The Areas under Consideration.

Gas-producing Area. — In that part of Ontario lying south and west of a
line drawn from Toronto to Collingwood, operations in search of gas and
petroleum have been carried on for a number of years. They have re-
sulted in the discovery of two gas-producing areas of considerable extent,
viz. that in Essex county, in the vicinity of Kingsville and Ruthven, and
that in Welland county, in the neighborhood of Sherkston. Nor are the
wells of these two fields the only producing ones, for many isolated bor-
ings^ such as those at Cayuga, Dunn ville' and Mimico, afford no incon-
siderable flows.

Oil-producing Area. — Petroleum has unfortunately been found in com-
mercial quantities in but one county, that of Lambton, where there are
two distinct pools, known as the Oil Springs and Petrolea fields. These
pools have been drawn upon continuously since 1862, when the first
flowing well was struck, in what is now known as the " upper vein." Fol-
lowing closely upon this discovery were more extended operations, which
brought to light the present oil horizon, known as the " lower vein." The
upper vein having long been exhausted, the source of supply has for
years been in the lower, wherein wells affording as much as 7,500 barrels
per day have been sunk.

Authorities indicated. — As I wish to treat more of the geologic than
the historical side of the question, I will follow out the title of my paper,
but before doing so cannot do better than refer those interested in the
oil industry in Ontario to Dr Robert Bell's paper on " The Petroleum
Field of Ontario,'' published in volume v, Transactions Royal Society of
Canada, and to the report of the Division of Mineral Statistics and Mines,
part S, Annual Report Canadian Geological Survey, volume iv, 1888-89.

Geologic Section of the Areas. — There is in that part of the province
under consideration a series of rocks, lying in almost undisturbed posi-
tion, ranging from the Trenton to the Portage formation, with an approx-
imate total thickness of 4,100 feet, as follows:

STRUCTURE OP THE HYDROCARBON FIELDS.

227

Devonian

Silurian

Cambro-Silurian

Formations.

Approximate A mk_

thickness m ■' r .

* i ncss inject.

r

Portage and Chemung

Hamilton, about

Corniferous

Oriskany

Lower Helderberg \
Onondaga J

Guelph 140

Niagara

Clinton

Medina

Hudson Liver

Utica

I Trenton \ Rnn

I Black Liver / uuu

25-

200

100

350

350

160-

300

230

6-

25

15

300-

1,000

650

140-

160

150

100-

130

115

30-

150

00

600-

sou

700

500-

000

700

300-

400

350

600-

750

075

Total.

4,125

The geologic Formations involved. ,,

«
Detailed Description essential. — To meet the requirements of this paper

it is perhaps 1 tetter to describe, so Car as is known, the various formations

in descending order.

Portage. — The Portage in Ontario consists of a series of fissile Mack
bituminous shales and is developed almost altogether in the county of
Lambton, where it acquires, according to Dr T. Sterry Hunt, a thickness
of 213 feet, as shown in a boring made at Corunna* These shales in a
well bored at Sarnia show a thickness of 80 feet, and again, in a well
sunk on lot 12, concession 10, Bosanquet township, they are seen to have
a total thickness of 95 feet. In both of these instances it lies immedi-
ately over the upper shale bed of the Hamilton formation, the upper
limestone bed of which, found at Petrolea and elsewhere, is wanting. In
the township of Dawn, and again east of Oil Springs, 7<> feet of black
shales are found. In this instance they rest upon the upper limestone
of the Hamilton. In a syncline lying between Petroleaand Oil Springs,
and separating the two fields, 40 feet of black shales are found in a well
drilled on Fox creek, the elevation of which is considerably less than
that of Oil Springs. These shales in no instance afford oil, but are prob-
ably the source of the considerable quantities of shale gas found in the
overlying gravel ami sand.

Hamilton. — Thewells in Petroleaand Oil Springs and the greater num-
ber of those drilled in Lambton county show that the black shales of the

1 Report of Progress, Geol. Survey of Canada, 1866, p. _:I7.

228 H. T. H. BRUMELL GAS AND PETROLEUM IN ONTARIO.

Portage group immediately overlie a limestone bed which constitutes the

upper stratum of the Hamilton formation. This series of rocks consists
of alternating beds of limestone and gray shales ( known locally as " soap-
stone ") and has a thickness, according to a drilling made at Kingstone's
mills, Lambton county, of 3% feet. Dr Hunt* speaks of this well as
being important in showing the thickness in Ontario of the middle and
upper Devonian, which, if we add to the 396 feet found here the 213
feet of rocks belonging to the Portage found at Corunna, is 609 feet.
The record of the well at Kingstone's mills is as follows:

Clay 14 feet,

Black shale 50 feet, P. >rtage.

Shales, soft, and limestone 39(5 feet, Hamilton.

Limestone, hard 44 feet, Coin i tennis.

At Petrolea the Hamilton is only 296 feet thick, as follows:

Limestone (" upper lime ") 40 feet.

Shale (" upper soapstone") . . 130 "

* Limestone ("middle lime") 15 "

Shale ('* lower soapstone ") 43 "

Limestone (" lower lime ") 68 "

At Oil Springs, 8 miles southward, the formation shows evidence of
having thinned out, the thickness there being only 240 feet according to
the following record of many wells drilled on the eastern side of the field :

Limestone (" upper lime ") 35 feet,

Shale (" upper soapstone ") 101 "

Limestone (" middle lime ") 27 "

Shale (" lower soapstone ") 17 "

Limestone (" lower lime ") ahout 00 "

Corniferous. — Underlying the so-called lower lime of the Hamilton is a
series of bituminous limestones constituting the Corniferous formation —
the source of the oil of Lambton county. Regarding the distribution of
this formation in Ontario, the following description is given :f

"The surface occupied by this formation in western Canada is probably between
0,000 and 7,000 square miles. A great part of this, however, is deeply covered with
drift, so that the exposures are comparatively few. To the eastward this forma-
tion is hounded by the outcrops already assigned to the underlying strata, the
limits of which in many parts have as yet been hut imperfectly traced. The whole
of the province to the west and south of this line belongs to the Corniferous forma-

* Report of Progress, Geo]. Survey of Canada, 1866, p. 251.
fGeology of Canada, 1863, p. 362.

DEVONIAN FORMATIONS OF ONTARIO. 229

tion, with the exception of a belt of higher Devonian rocks which crosses the
country from Lake Huron to Lake Erie and divides the region into two areas.
These newer strata occupy a saddle-shaped depression in the great Cincinnati anti-
clinal, which runs nearly east and west through the peninsula, while the course of
this depression or synclinal is nearly north and south from Plympton, on Lake
Huron, to Orford, on Lake Erie. The belt of higher rocks has a breadth of only
about twenty-five miles on the anticlinal between the Thames and Sydenham
rivers, but on either side it spreads to the northeast and to the southwest along the
shores of the two lakes."

In two wells, those of London and the " Test well," at Petrolea, the
Corniferous is shown to have an approximate thickness of about 200 feet,
consisting throughout of hard gray limestone. In all wells where this
formation has been struck the rocks appear to have been of uniform
character and to consist of white or grayish limestones holding nodules
and layers of chert.

Oriskany.— The Oriskany formation is but slightly developed in Ontario,
being entirely wanting in most of the wells sunk to or beneath its horizon ;
again, owing to the carelessness of drillers, its presence may not have
been noted. In the townships of Oneida and north Caynga, in Haldi-
mand county, it is exposed and forms beds of sandstone aggregating at
the most twenty-five feet in thickness. In many of the records obtained
from drillers mention is made of a sandstone at about the summit of the
Onondaga, but in most cases close inquiry has proven these statements
to be fallible, the so-called sandstone being generally a granular dolomite.
However, in two wells at least there is strong, evidence of a sandstone
occurring at a point near the position occupied by the Oriskany. One
of these was a well drilled at Dresden, Camden township, Kent county,
wherein the following record was met with, according to the driller:

Surface deposits 43 feet.

Shale, black 180 "

Limestone 12 "

Shale ("soapstone") 172 "

Limestone 75 "

Sandstone 44 "

Again, in a well sunk near Dresden, on lot 3, concession 2, Camden
township, the following section was, according to the driller, obtained :

Sn [face deposits 00 feet,

Shale, black 20 "

Limestone 30

Shale (" soapstone ") 204 "

Limestone 117

Sandstone -10

230 II. P. II. BRUMELL — GAS AND PETROLEUM IN ONTARIO.

Onondaga and Lower Hdderberg. — Beneath the Oriskany, when present,
and usually directly underneath the Corniferous limestone, is a long
series of limestones, dolomites, marls, shales, gypsum, and salt constitut-
ing the Onondaga, which for convenience can be made to include the
Lower Helderberg. This formation acquires a thickness, in the salt
region of Huron county, of at least 1,500 feet, according to the following
very accurate record made by Dr T. Sterry Hunt* of a well sunk at
Gloderich by Mr Henry Attrill,- of that place:

/•'( i I. Inrlies.

Surface deposits 7S U

Dolomite, with thin limestone layers 278 3

Limestone, with corals, chert and beds of dolomite 27(3 0

Dolomite, with seams of gypsum 24."> 0

Variegated marls, with beds of dolomite 121 ()

Rock-salt, first bed 30 11

Dolomite, with marls toward the base 32 1

Rock-salt, second bed 25 4

Dolomite G 10

Rock-salt, third bed 34 10

Marls, with dolomite and anhydrite 80 7-

Rock-salt, fourth bed 15 5

Dolomite and anhydrite 7 0

Rock-salt, fifth bed 13 6

Marls, soft, with anhydrite 135 G «

Rock-salt, sixth bed ' G 0

Marls, soft, with dolomite and anhydrite lo2 0

Total depth . . : 1,517 0

As to what is the greatest actual thickness of the formation it is im-
possible to say, as data regarding its lower measures are wanting. In
none of the records obtained has there been definitely noted the red and
greenish shales indicative of the base of the formation in New York state.
According to the records of wells sunk for gas in Bertie township, Wel-
land county, it has there a total thickness of 390 feet, consisting of gray
and drab dolomites, black shale and gypsum, and in a well at Petrolea
it was found to be 905 or more feet thick, as follows :

Limestone, hard, white 500 feet.

Gypsum SO "

Salt and shale 105 "

Gypsum SO "

Salt and shale 140 "

The formation may be thicker, as drilling ceased in the salt and shale.

* Report of Progress, Geol. Survey of Canada, 1S70- 77.

SILURIAN FORMATIONS OP ONTARIO. 231

Guelph. — Underneath the Onondaga, is met with, over a considerable
portion of the province, a series of yellowish to brown and in places
bituminous dolomites, having a probable thickness of not more than 160
feet and known as the Guelph formation. These beds have been pierced
in many wells in Ontario, but efforts to obtain from drillers definite in-
formation as to their thickness and character have been useless, nor has
it been found possible to draw any distinction, in records of wells so far
obtained, between the dolomites of this formation and the gray dolomite
of the Niagara, which immediately underlies it. In the wells of the Bertie
township, Welland county, gas field are found about 240 feet of dolomites
of Guelph and Niagara age, and in number 1 well sunk by the Port
Colborne Natural Gas Light and Fuel company in Humberstone town-
ship, Welland county, there are found, according to the driller, 30 feet
of shaly dolomite and 188 feet of brown dolomite, with dark-blue shales
toward the bottom. In the town of Paris a well was sunk in which 99
feet of Guelph dolomite was found immediately underlying the Onon-
daga. The boring was not continued beyond this depth, so it is impos-
sible to say what thickness the formation attained at this point.

Niagara. — The Niagara formation, the upper beds of which are com-
posed of dolomites, as stated above, has a probable thickness in Welland
county of about 140 feet, made up of gray dolomites reposing upon about
50 feet of dark shale. It extends throughout the province in a north-
westerly direction to Cabotshead, where, according to the Geology of
Canada, 1863, it would have a thickness of about 450 feet, and is com-
posed of a whitish subcrystalline limestone. On the Welland canal, near
Thorold, is seen the following section in ascending order:*

Bluish-black bituminous shale 55 feet.

Bluish-gray argillaceous limestone 8 "

Dark bluish bituminous limestone 8 "

Light and dark -gray magnesian limestone 20 "

Bluish bituminous limestone 7 "

Total 104 "

This section does not include two 10-foot beds of bluish-gray magne-
sian limestone which maybe of Clinton age, though toward their summit
holding two species of fossils characteristic of the Niagara series in New
York, nor does it reach the summit of the formation. In Essex county
the beds met with in the various wells sunk near Kingsville and Ruth-
ven at a depth of from 1,000 to 1,100 feet consist of a light yellowish-gray
vesicular dolomite which is probably of Niagara age. It is from this
dolomite that the lame flows of gas have been obtained.

I Geology of Canada, 1863, p. 322.

161 II. P. II. BRUMKLL — GAS AND PETROLEUM IN ONTARIO.

Clinton. — The Clinton, on entering Canada through the Niagara penin-
sula, consists of a band of green shale 24 feet thick underlying IS feet of
limestone, though in the wells of the Provincial Natural Gas and Fuel
company in Bertie township the shales are apparently entirely wanting,
the formation consisting, it is said, of 30 feet of white crystalline dolomite,
which is grayish toward the base. In number 1 well of the Port Col-
borne company there were found beneath the dark shales, indicative of
the base of the Niagara. 72 feet of marls and dolomites, which are in all
probability attributable to the Clinton. The formation appears to thicken
toward the northwest, gradually diminishing again, as proved by the ex-
posure which trends to the north from Hamilton toward Collingwood, a
little south of which it takes a sweep to the westward. In Wentworth
county, in the township of Flamborough West, the Clinton is seen to rest
upon about 8 feet of whitish sandstone, constituting the " gray band,"
which is apparently missing in Welland county, but on the northern
extension of the formation proves a very conspicuous feature, forming a
terrace upon which the' shale and limestone of the upper part of the
Clinton occur. In the many records of wells drilled in the interior of the
province evidence is wanting to estimate the thickness or character of
the Clinton, though in one, that of a boring at Waterloo, there were said
to have been found 114 feet of blue shale lying immediately above red
shale undoubtedly of Medina age. In all probability there have been
included in this 114 feet the dark shales of the Niagara.

Medina. — Following immediately upon the Clinton and, where present,
the sandstone of the gray band is a great thickness of red and white
sandstones and red and green shales which constitute the Medina. This
formation has its greatest thickness in the Niagara peninsula, gradually
diminishing toward the north, where, at Cape Commodore, in Grey
county, there are seen beneath the Clinton limestone 109 feet of red and
green shales resting upon strata of the Hudson River formation. In
number 1 well, drilled in Port Colborne by the Port Colborne company,
the measures penetrated for a distance of 770 feet were —

Red shale, with thin bands of white sandstone 50 feet.

Red and white sandstone 53 "

Soft red shale, with bands of gray and green G07 "

Total 770 "

Drilling ceased at this point at a distance of at least 200 feet above the
base of the formation, as in a well on lot 6, concession 15 of Bertie town-
ship, there were found 1,000 feet of strata attributable to the Medina.
The best record of the upper beds of the formation is that of the bottom

SILURIAN FORMATIONS OP ONTARIO. 233

of number 1 well, drilled by the Provincial company, on lot 35, conces-
sion 3, Bertie township, and which is as follows:

Red sandstone , 55 feet.

Red shale 10 "

Blue shale 5 "

White sandstone 5 "

Bine shale 20 "

White sandstone (" gas-n >ck ") 1(3 "

Total , Ill "

Throughout the gas-fields of Bertie and Humberstone townships this
section of the upper bods of the formation appears to lie unite constant,
only very slight variations being noted. The most marked is that in
number 9 well, drilled by the same company, and wherein was found —

Red sandstone 55 feet.

Red shale 10 "

Blue shale 5 "

White sandstone .• 20 "

Illue shale 12 "

Total 102 "

The second white sandstone bed beneath was penetrated only four feet.

in a well sunk on lot 11, concession 7, Barton township, Wentworth
county, and about forty miles to the northwest of the above-mentioned,
there were found 595 feet of red shale, with bluish bands, lying imme-
diately above the bluish shales of the Hudson River. Again, a few
miles northwest of this place, and at the insane asylum in Hamilton,
there were said to have been found 634 feet of red shale, and at Dundas,
three miles north of this, in a well sunk in the valley and begun in the
Medina, there were found 400 feet of red shale, in both instances resting
upon the Hudson River shales. To go back to the eastward again, there
were found in a well at Saint Catharines .548 feet of red shale. This does
not, however, show the entire thickness of the measures, which in a well
at Thorold, eight miles southward, proved to be 930 feet thick, as follows :

Red sandstone 30 feet.

Shale 57 "

Gray sandstone 30

Red shale 813 "

Total 930 "

XXXV— Bull. Geol. Soc. Am., Vol. 4, 1882.

234 II. P. IT. BKUMELL — GAS AND PETROLEUM IN ONTARIO.

Many other records of wells bored into or through this formation are
at hand, which go to show that it varies locally as to thickness, yet con-
stantly diminishes toward the north. Of the formation in the western
part of the province but little is known, as west of London, where it con-
sists of 500 feet of red shale, it has not been reached in the borings thus
far put down.

Hudson River. — The Hudson River, which is next met with, plays a
very unimportant part in the geology of gas and oil in Ontario, and con-
sists, in that part of the province under consideration, of a series of shales
and limestones immediately underlying the red and green shales of the
Medina. Unfortunately the great area of its supposed exposure north of
Toronto is overlaid with drift, but where the exposures are to be seen
they consist, as in the township of Toronto, Peel county, " of a scries of
bluish-gray argillaceous shales enclosing bands of calcareous sandstone
sometimes approaching to a limestone and of variable thickness.'1 *
These sandstone bands are slaty in places, though at times having a solid
thickness of a foot. The formation has been reached in a considerable
number of wells — among others, those at Saint Catharines, Thorold,
number 14 of the Provincial company, in Bertie, all in the Niagara
peninsula; Swansea and Mimico, near Toronto; Toronto, Hamilton,
Brantford and London, where it was penetrated for 150 feet and found to
consist of limestone and shale. In the wells at Swansea and Mimico
there were found 440 and 493 feet respectively of bluish-gray shale.
This does not of necessity represent the total thickness of the formation
at these points, as boring began upon it immediately beneath the surface
deposits, in the Thorold well, where the formation was met with at
depth, it was found to consist of 700 feet of blue shale, and at Saint
Catharines it had a similar character and thickness. It is quite probable
that in the various borings limestone was found, though on account of
its shaly character it was termed shale by the drillers.

Utica. — The Utica formation, upon which the Hudson river rests, is
found, wherever met with in drillings, to consist of a series of dark-brown
bituminous shales, becoming in places bluish toward their base, and
having a thickness of from 200 to 400 feet. Of its exact thickness in any
well it is very difficult to speak, on account of the similarity between its
upper members and the lower strata of the Hudson river.

Trenton and Black River. — Beneath the Utica shales there is met with
a thick series of bluish limestones, which constitute the Trenton forma-
tion, including also the Black River. This series, which is regarded as
the Mecca of all Ohio drillers, has proved itself, in Ontario, to be com-

*Geology of Canada, 1863, p. 212

SILURIAN FORMATIONS OF ONTARIO. ZOO

paratively barren of gas or oil. Of its productive properties, however,
more will be said later. In eastern Ontario it covers a large area, but
west of Toronto and Collingwood the series is overlaid by the Utica an 1
newer formations, with the exception of a small area in the vicinity of
Collingwood, where it is seen to consist of bluish limestone, having a
slight dip to the southwest. In the few wells wherein it has been reached
the character of the rocks is apparently unchanged, though its thickness
varies considerably. For instance, at Whitby, east of Toronto, it has a
thickness of 600 feet; at Toronto, 585 feet; Swansea, 602 feet; Colling-
wood, 553 feet, and Saint Catharines, 667 feet, in all of which places the
formation was entirely traversed, the drillings, with the exception of the
well at Saint Catharines, ceasing on the striking of the Archean rocks
immediately beneath. In the case of the boring at Saint Catharines the
drill, penetrated 27 feet of white quartzose sandstone, which may be Pa-
leozoic or belong to the arkose beds.

Geologic Horizons in Ontario yielding Gas and Oil.
oil wells in the corniferous limestone.

Age and Depth. — Of the occurrence of petroleum in Ontario but little
can be said. In Lambton county, where it has been produced for 30
years, it is found in the Corniferous limestone at a depth of about 475
feet, the record of a well bored near the Imperial refinery, Petroleaj
being as follows :

T, „, , Thickness in

Formation. Strata. ^gej

Surface deposits 104

f Limestone 40

| Shale 130

Hamilton -J Limestone 15

| Shale 4:5

I Limestone 68

„ .c i Limestone, soft 40

Corniferous

1 Limesti me, gray, oil rock zo

Depth 465

Annual Output of Oil. — Some 3,000 wells are now producing and afford
about 800,000 barrels per annum, making the average daily production
about two-thirds of a barrel per well. The oil is dark-colored and of
from 31° to 35° Baume in gravity; nor is it an oil that can be easily
refined, on account of the considerable proportion of sulphur it contains
in a form as yet undetermined.

236 H. T. II. BRUMELL — GAS AND PETROLEUM IN ONTARIO.

Chemical Composition of the Oil. — According to returns received from
the refineries for the year 1880 it has a commercial content of —

Benzine and naphtha L6 per cent.

Illuminating oil 3S.7 "

Paratfine, gas and other oils and wax L'."i.."> "

Waste (coke, tar and heavy residuum) :}4.4 "

100.0

The Corniferous petroliferous over awide Area. — While the Corniferous af-
fords commercial quantities of oil only in Lambton county, explorations
have proved it to he petroliferous over a wide extent of country, including
the northern part of Kent, the eastern part of Middlesex, and southern
part of Oxford. In the county of Essex oil has been found at two points,
presumably in the Niagara or upper strata of the Clinton. At Comber,
in this county, small quantities of heavy black oil were found in a hard
limestone at 1,270 feet, and again at Walker's well number 2, on lot 8,
concession 6, Colchester township, oil similar in appearance and gravity
was found at 1,000 feet in a brownish limestone. This well is said to
have pumped five barrels per day.

THE MEDINA AS AN OIL-PRODUCER.

The only other formation wherein oil has been struck is the Medina,
in which, in Humberstone township, Welland county, it has been noted
in two wells. These are on lots 11 and 12, concession 3, and are said to
have flowed four and two barrels each per day respectively. The oil
occurs in the second white sandstone bed, about 100 feet beneath the
summit of the formation. The oil is of light claret color, of about 45°
Baume gravity, and is apparently free from sulphur. Further work in
search of this oil has not yet been undertaken.

GAS-BEARING HORIZONS: CLINTON, MEDINA AND OTHERS.

Localities indicated. — Gas is found in large quantities at two horizons
only, viz, one, which is still doubtful though in the neighborhood of
the Clinton, in Essex county; and in the Medina, in Welland. In the
former county, in the vicinity of Ruthven, Gosfield township, there have
been sunk several wells, in three of which were found huge quantities of
gas, in each ease emanating from a gray vesicular dolomite at a depth
of about 1,000 feet.

Depth at which Gas is found. — In Welland count}', wherein the gas field
covers a much greater area than that of Essex, the gas is found almost
entirely in the Medina sandstone, about 100 feet below the summit of
the formation and at a depth of about 830 feet. The record of number 1

DEPTH AND CAPACITY OF WELLS.

237

Thickness
in feet.

9

well, drilled on lot -'55, concession 3, Bertie township, by the Provincial
Natural Gas and Fuel company, is a follows :

Formation. Strata.

Surface deposits •

Corniferous Dark-gray limestone

Onondaga Gray and drab dolomites, black shales and gypsum. .

Guelph and Niagara. . . Gray dolomite

Niagara ... Black shale

Clinton White crystalline dolomite, gray toward bottom. . .

Red sandstone

Red shale

Blue shale

White sandstone

Blue shale

White sandstone (" gas-rock ")

Medina.

Total .

390

240

50

30

55

10

5

5

20
16

846

Records of twenty-eight Wells. — In the above well 2,000 ,000 cubic feet of
gas per day were struck at a depth of 836 feet, or six feet in the second
white sandstone bed. This company have drilled some thirty wells, the
records of which do not differ materially from that given above, though
capacity varies greatly, as may be seen from the following table :

Number of the
well.

1.

9

Cubic feet per
day.

. 2,050,000
375,000
600,000

. 2,200,000

3

-1

5 8,500,000

6 70,000

7 3,000,000

8 47,000

.9 3,500,000

10 4,500,000

11 300,000

12 5,500,000

13 300,000

14 5,000

Number of the
well.

Cubic feet per
day.

15 50,000

16 12,500,000

17 2,500,000

18 2,000,000

19 1,500,000

20 300,000

21 None.

22 2,600,000

23 30,000

25 500,000

26 2,750,000

27 None.

28.-. Limited.

Gas-bearing Bed of the Medina. — In all of these wells, with the exception
of number 22, the entire flow was obtained from the second white sand-
stone bed of the Medina; nor are these the only wells producing large
quantities of gas from that horizon, as shown below.

Daily Capacity of some of (he Wells. — The largest gas well is that known
as Coste number 1, drilled by the Ontario Natural Gas company on lot
7, concession 1, of Gosfield, and carried to a depth of 1,021 feet, wherein

238 n. j'. n. brumell — gas and petroleum in Ontario.

at 1,017 feet a flow of gas equal to 10,000,000 cubic feet per day was
found. Another was drilled by the Citizens' Gas, Oil and Piping com-
pany of Kingsville on the road allowance aboui 55 yards west of the
above-mentioned well, and afforded 7,000,000 feet per day, from a rock
similar in character and depth to that in Coste number 1. On lot 7,
concession 1, of Gosfield. the Citizens' company again drilled and found
gas to the extent of 2,500,000 cubic feet per day, and I understand that
the Ontario company have been quite successful in a boring made
southeast of their Coste number 1, having obtained there a heavy flow,
estimated at 7,000,000 feet per day. All efforts to find gas north and
northwest of this group of wells have been futile, the beds being found
to be flooded with salt water.

Other Localities. — Among other lesser producers may he mentioned
Carrolls, in Humberstone township, which afforded 1,000,000 cubic feet
per day. At Cayuga, in Haldimand county, west of Welland, a consid-
erable flow was found in the Medina as well as at Dunnville, about mid-
way between Port Colborne and Cayuga. In wells bored to or through
the Medina north and northwest of Welland, and the wells mentioned
above, the formation has been found to be practically barren of gas, the
only boring wherein it Avas noted being at Beeton. where in a soft sand-
stone just beneath the surface deposits a small quantity occurred.

The Clinton a* a Gas-producer. — The Clinton in a small number of wells
has afforded large quantities of gas, the most marked instances being
those in Welland count}r, known as Near's, Reebe's and Hopkins' num-
ber 2, each of which produced 400,000 cubic feet per day, and the Mu-
tual company's well, which produced 1,500,000 cubic feet. These wells
are all in that district wherein the Medina is so productive, a fact that
rather tends to suggest that the gas is adventitious. Outside of this
count}7 the Clinton has not as yet produced a single cubic foot of gas.
Exception must, of course, be taken to this statement if it be proved that
the productive horizon in Essex county is in that formation.

The Niagara as a das- producer. — In Welland county the Niagara also
is a large producer of gas. well number 22 of the Provincial company
affording 1,850,000 cubic feet per day from the limestones of the upper
part of the formation, while in a well sunk a few miles north of this, at
Niagara Falls South, a flow of 50,000 cubic feet was obtained in the shales
beneath the limestone.

OTHER GAS-BEARING FOli.VATIOXS.

There now remain to be spoken of only three formations which have
afforded gas, though only as yet in small quantities. They arc the
Onondaga, the Trenton, and a sandstone of age anterior to the latter.

GAS FROM THE TRENTON AND ONONDAGA. 239

The Onondaga as a Gas-producer. — The occurrence of gas in the Onon-
daga, even in the small quantities noted, is unique. At Blyth, Huron
county, and in the midst of a considerable number of wells bored in the
salt region, a well was drilled which afforded, according to the driller,
the following record :

Surface deposits 104 feet.

Limestone 300

(?) 346 "

" Black shale " 100 "

"Hard rock" 170 "

Shale 105 "

Rock-salt 00 "

Total 1,215 "

In the black shales considerable quantities of gas were obtained, not,
however, sufficient to he of commercial value.

The Trenton ax a Gas-producer. — The Trenton formation has not as yet
afforded any considerable quantities of gas, though pierced at many points,
the most westerly being Stratford, where it was found at 2,360 feet and
penetrated for 24 feet, where a heavy flow of salt water caused the abandon-
ment of the work. Coining eastward, the point where it was next struck
was on lot 16, concession 15, Brantford township, Brant county, where
it was reached at a depth of 1,950 feet and a small quantity only of gas
obtained at its summit. At Dundas, near Hamilton, in Wentworth
county, it was struck at 1,43!) feet and found to he barren. Again, at
Thorold, Welland county, about 40 miles east of Hamilton, the Trenton
was struck at 1,905 feet and penetrated for 525 feet, where a very small
How of gas was noted. About S miles north of this, at Saint Catharines,
it was again reached, being struck at 1,506 feet and found to be barren,
although the entire formation was traversed. Again east of Thorold and
on lot 6, concession 15, of Bertie township, it was struck at 2,525 feet in
well number 14 of the Provincial company, wherein it was traversed for
195 feet without affording gas. The foregoing three wells are the only
ones in which the Trenton was reached south of Lake Ontario. On the
northern side, however, it has been met with in all wells drilled close to
the lake shore. In Toronto several wells were sunk, operations com-
mencing upon the Hudson River formation and the drilling continued
deep into or through the Trenton without finding gas; but at Mimico,
about 8 miles west, three wells have afforded small quantities, the great-
est flow being about 50,000 cubic feet per day. In and around Colling-
wood several wells, beginning in the upper beds of the formation and
continued to its base, afforded small Hows, the greatest being about 6,000
cubic feet per day.

240

II. P. ir. BRUMELL — GAS AND PETROLEUM IN ONTARIO.

It will thus be soon that in Ontario the Trenton as a large producer
has proved so far anything but successful. Even at lunulas, on the
crown of the Dundas anticlinal, no gas was found. There, however, re-
mains in the western and southwestern portion of the province a large
area as yet untouched, wherein it may afford large quantities and prove
of as great value as it has further southward, in Ohio.

The following table exhibits the position of the Trenton in southwest-
ern Ontario in regard to tide level.

Locality of well.

Toronto, Swansea . . .

Mimico

Collingwood, City. . .
Delphi.

Dundas

Saint Catharines. . . .

Thorold

Provincial company,

numbei 14

Brant ford

Stratford

Elevation

of well
above tide.

Feet.

About

347
250

592
600
300
.297
517

About 020
672

1,185

1,

Elevation

of
summit of

Trenton.

Feet.

— 296

— 44:;

Begun on
+ 552

— 1,130

— 1,21)'.)
— 1,388

- 1,905
-1,278

- 1,175

Thickness

of
Trenton.

E < t.
602

Trenton.

flii7

Elevation

of base

of Trenton.

Feet.

— 898
Not reached.

+ 39
Not reached.
....do

— 1,876
Nut reached.

.do

.do

.do

I las in Tren-
ton— cubic
feet per day.

None.

A I .out 5,000

" r,,ooo

" 0,000
None.

None.
Very small.

None.

Very small.
None.

Unfortunately no analyses or close examinations have as yet been
made of the Trenton limestone in that part of the province under con-
sideration, the only analyses available being those of specimens from
quarries considerably to the east of the portion where it is under cover.

An unusual Occur re ace of Gas. — A rather peculiar occurrence of gas is
that found in the well near Saint Catharines. In this boring a yellow
quartzose sandstone beneath the Trenton limestone was penetrated for
seventy-seven foot and afforded a small quantity of gas, insufficient for
commercial purposes.

Forthcoming Publication on the Subject.

In closing, I should like to draw attention to the fact that a detailed
description of wells bored in Ontario, accompanied by maps and sections,
is now in press and will shortly he issued by the Canadian Geological
Survey. In this will be found a more or less complete narrative of bor-
ing operations tip to the close of the calendar year 1890.

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA

Vol. 4, pp. 241-244 May 20, 1893

NOTES ON THE OCCURRENCE OF PETROLEUM IN GASPE,

QUEBEC

BY H. P. H. BRUMELL

(Read before the Society December 30, 1892)

CONTENTS

Page

Earlier History 241

The Locality indicated 2-11

The Oil-bearing Formation described 241

Former Knowledge concerning the Locality 242

Kecent Exploitation 243

History of later Operations not fully known 24 '

Notes on past and present Investigations 243

Continuation of Investigations probable 244

Earlier History,

The Locality indicated. — Operations in search of petroleum have been
carried on in a desultory manner for about 30 years in the vicinity of
Gaspe basin, Gaspe county, Quebec, without as yet any economic result.
The presence of oil at depth has, however, been proved through the
efforts of " The Petroleum Trust," an English company, which has been
operating on the southwest side of Gaspe bay, in the neighborhood of
and to the south of Gaspe basin.

The Oil-bearing Formation described.— in the eastern part of the Gaspe"
peninsula there is a great thickness of sandstones resting conformably
upon almost as great a thickness of limestones, the whole being of lower
Devonian and possibly partly Upper Silurian age. According to Dr R.
W. Ells* these sandstones have a thickness of about 3,000 feet, while the

* Report of Progress, Geol. Survey of Canada, 1880-82, p. 5 D D.
XXXVI— Bull. Geol. Soc. Am., Vol. 4, 1892. (241)

242 II. 1'. II. BRUMELL — PETROLEUM IX QUEBEC.

underlying limestone is estimated at about 2,000 feet. These roeks are
largely developed in the vicinity of Gaspe bay, where they form a scries
of almost parallel anticlinals, on or near the axes of which the greater
part of the exploratory work has been done.

Dr R. W. Ells, in the report cited above, speaks of these anticlinals as
follows :

"The rocks of the series have a considerable development on the several rivers
that How into Gaspe hay, where they lie in shallow basins, bounded by the anti-
clinals, which bring into view the strata of the lower or Gaspe limestone series.
These basins are at least four in number, the dividing anticlinals being known as
the Haldimand, the Tar Point, the Point Saint Peter, and the Perce, the most
southerly yet recognized. On the south side they rest upon rocks of the Silurian
system. The whole formation may therefore be said to occupy a geosynclinal basin,
the western limit of which has not yet been traced, but which will probably be
found to be continuous with the basin recognized on the Cascapedia river, ami
thence extending to the Metapedia."

Former Knowledge concerning the Locality. — In the " Geology of Canada,"
1863, page 789, the following mention is made of the various natural oil
springs of the district. This includes probably all that was known of the
occurrence of oil in Gaspe up to that date :

"At the oil spring at Silver brook, a tributary of the York river, the petroleum
oozes from a mass of sandstone and arenaceous shale, which dips southeastwardly
at an angle of 13° and is nearly a mile to the south of the crown of the anticlinal.
The oil, which here collects in pools along the brook, has a greenish color and an
aromatic odor, which is less disagreeable than that of the petroleum of western
Canada. From a boring which has been sunk in the sandstone to a depth of about
200 feet there is an abundant flow of water, accompanied with a little gas and very
small quantities of oil. Farther westward, at about twelve miles from the mouth
of the river, oil was observed on the surface of the water at the outcrop of the lime-
stone. Petroleum is met with at Adams' oil spring, in the rear of lot B of York,
nearly two miles east of south from the entrance of Gaspe" basin. It is here found
in small quantities floating upon the surface of the water, and near by is a layer of
thickened petroleum, mixed with mold, at a depth of a foot beneath the surface
of the soil. A mile to the eastward, at Sandy beach, oil is said to occur, and, again,
at Haldimandtown, where it rises through the mud on the shore. These three
ocalities are upon the sandstone and on the line of the northern anticlinal which
passes a little to the north of the Silver Brook oil spring. Farther, to the southeast,
on the line of the southern anticlinal and about two miles west of Tar Point, which
takes its name from the petroleum found there, another oil spring is said to be
found, three-quarters of a mile south of Seal cove. On the south side of the Doug-
lastown lagoon, and about a mile west of the village, oil rises in small quantities
from the mud on the beach. A well has here been bored to a depth of L25 feel in
the sandstone, which dips to the southwest at an angle of 10°, but traces only of
oil have been obtained. Farther to the westward oil is said to occur on the second
fork of the Douglastown river. Traces of it have also been observed in a brook

RECENT OPERATIONS IN GASPE] 213

near Saint George's cove, on the northeast side of Gaspe hay. In none of these
localities do the springs yield any large quantities of oil, nor have the borings, which
have been made in two places, been as yet successful. The above indications are,
however, interesting, inasmuch as they show the existence of petroleum over a
considerable area in this region, some part of which may perhaps furnish availa-
ble quantities of tins material."

Recent Exploitation.

History of biter Operations not fully knoion. — Regarding later operations
but little is known, as owing to the distance from our usual fields of
work and the disinclination of operators to impart information it has
been found impossible to closely follow actual operations. However, this
much is known, that oil has been found at some depth, though in small
quantities. ■

Notes on past and present Investigations. — The following notes are gleaned
from a report on mines and minerals of the province of Quebec recently
prepared by J. Obalski, M E, supplemented by information obtained by
the writer :

At Sand}r Beach, on lot B, York township, two wells were sunk about
20 years ago, one of which is said to have afforded oil, and about a mile
above Douglastown, on the southern side of the Saint John river, a well
was sunk 125 feet without successful result. At Silver Brook two wells
were bored to a depth of 800 and 900 feet respectively, both showing the
presence of petroleum, and on the southern side of the York river, near
Silver Brook, two borings were made by the Gaspe Oil company to a depth
of 700 and 800 feet, in neither of which was oil struck. Subsequent to
these a well was sunk at Sandy Brook to a depth of 700 feet, in which
oil was found, though in small quantity. The oil, a specimen of which
was collected in 1882 by the writer, was brought to the surface of a small
pool by the water, which flowed in considerable quantity from the boring,
and was a heavy black oil of about 25° Baume gravity.

in 1888 the International Oil company of Saint Paul, Minnesota,
sunk a shallow well, which was in 1889 deepened to 450 feet without
finding oil. The lands and plant owned by this company Were in the
same year taken over by "The Petroleum Trust." which lias since
sunk five wells in the district. In one of these, bored at Seal cove, a
short distance south of the crown of the Tar Point anticlinal, they have
met witli a small quantity of high-grade oil. According to one of the
drillers, the boring reached a depth of 3,000 feet, of which the upper
2,150 consisted of yellow and white sandstone, followed by 850 feet of
bluish shaly limestone, in which, at a depth of about 2,600 feet from the

244 H. P. H. BRUMELL — PETROLEUM TN QUEBEC.

surface, the oil was found. The oil, which is green in color, is of about
38° Baume gravity, has an aromatic odor, and is bright ruby red by
transmitted light.

Continuation of Investigations probable. — The company working at pres-
ent expect to continue operations, the results of which, in view of the
probable exhaustion in the near future of the Petrolea field in Ontario,
will be watched with interest.

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA
VOL. 4, PP. 245-256 JUNE 8, 1893

THE FAUNAS OF THE SHASTA AND CHICO FORMATIONS

BY T. W. STANTON

(Read before the Society December 30, 1802)
CONTENTS

Page

Historical Review , 245

Earliest Literature 245

Views of W. M. Gabb 246

The Tejon Controversy 246

Work of the Canadian Geological Survey 248

White's Classification of the California Cretaceous 249

Relation of Shasta and Chico Faunas 241>

Identity of Faunas indicated 24!)

Local Lists of both Faunas from northern California 250

Original Localities of Chico Fossils 253

Faunas of Queen Charlotte and Nanainio Formations 253

Correlation of Queen Charlotte Formation with the Shasta 253

Correlation of Nanaimo Beds with the Chico 254

The Shasta-Chico Fauna compared with the Fauna of the Blackdown Beds . . 254

Conclusions 255

Historical Review,

Earliest Literature. — The earliest published opinion concerning the age
of the beds now known as the Chico formation seems to be that of Dr
J. B. Trask * who described Ammonites chicoensis and Baculites chicoensis
in 1856. On account of the modern aspect of the fossils associated will:
those species he referred the strata containing them to the upper Eocene.
Shortly afterward Professor J. S. Newberry f discussed the same beds,

*Proe. Cal. Aead. Nat. Sci., vol. i, 1850, p. 85.

t Pacific R. R. Reports, vol. vi, pt. 2 [1857?], pp. 24, 25. The title-page bears the date 1855, but there
is internal evidence that the volume was not published before 1857.

XXXVII-Bui.l. Geoi.. Soc. Am., Vol. 4, 1892. (245)

240) T. W. STANTON SHASTA AND CHICO FAUNAS.

and, while admitting the presence of modern types of mollusks, consid-
ered that the cephalopods were stronger evidence of their Cretaceous age.
He also stated that he had obtained a collection of fossils from Nanaimo,
Vancouver island, that proved the Cretaceous age of the coal beds at that
place. These fossils were placed in the hands of Professor P. B. Meek,*
who soon afterward described them. Although at that time he thought
that the entire collection came from Nanaimo, he believed that two dis-
tinct horizons were represented. Many years afterward, when repub-
lishing the descriptions with figures,t he stated that only those species
which he believed to be the older came from Nanaimo, while the others
were from Comox, northwest of Nanaimo, and from Sucia island. Those
from the last two localities were thought to indicate about the horizon of
the Fort Pierre shales, or number 4 of Meek and Hayden's upper Mis-
souri section.'!

In 1858 Dr B. F. Shumard § described three species of Cretaceous
fossils from Nanaimo, and in 1861 Dr James Hector || published an
account of the Nanaimo coal field, giving the evidence of its Cretace-
ous age.

Views of W. M. Gabb, — Up to this time both the geologic and the pale-
on tologic work had been mainly preliminary, the latter based on very
small collections brought in by explorers; and it was not until 18(34,
when the first volume of the Paleontology of California was published,
that any serious attempt was made to classify the Cretaceous formations
of the Pacific coast or to present their paleontology in a systematic
manner. In that volume Mr W. M. Gabb described about 260 species
of fossils which he referred to the Cretaceous. In the introduction some
general statements concerning the classification and correlation of the
California Cretaceous were given by Professor J. D. Whitney ,^[ the state
geologist, on the authority of Mr Gabb. All the Cretaceous beds on the
Pacific coast were assigned to two divisions {A and 7>), winch were to-
gether supposed to represent the Upper Chalk or White Chalk of Europe
and the Fort Pierre and Fox Hills groups of the upper Missouri, although
the Cretaceous of the latter region seemed to have no species in common
with the California strata.

The Tejon Controversy. — The publication of this volume precipitated a
discussion between Messrs Gabb, Conrad and others as to the age of

* Trans. Albany Institute, vol. iv, 1858-'64, pp. 36-49.
i Bull. U. S. Geol. Snrv. Terr., vol. ii, 1876, pp. 351-374.

[The same opinion is expressed in Professor Week's last work-, 1'. S. Geol. Surv. Terr., vol. ix,
Invert. Paleontology, p. xxv.
I Trans. St. Louis Acad. Sri., vol. i, 1858, pp. 123-125.
|| Quart. .Jour. Geol. Soc. Liond., vol. xvii, 1861, pp. 428-436.
«| Paleontology of Cal., vol. i, L864, p. xix.

EOCENE FACIES OF THE TEJON. 247

division "2?," now known as the Tejon formation, Mr Conrad asserting
that it is Eocene and Mr Gabb as strenuously maintaining its Cretaceous
age* On the one hand, the unquestionable fact that a number of the
fossils are identical or closely related with species that elsewhere charac-
terize the Eocene was regarded as proof of its Tertiary age ; while on the
other hand, the presence of an ammonite (Ammonites jugalis) and the
apparently close faunal and stratigraphic connection with the Cretaceous
beds beneath were believed to prove its Cretaceous age. According to
Mr Gabb's f statement in one of his controversial articles, 23 species of
the 107 in division B are found in the underlying beds. When his
list of common species is critically examined, however, it is seen that,
with the exception of the Ammonites and perhaps two or three others, they
all belong to genera that have lived from the Cretaceous or earlier to the
1 tresent time without undergoing much change. Professor Angelo Heil-
prin \ has given a careful review of all the published evidence bearing
on this question, and in preparing it he has studied a large part of Mr
Gabb's original collections of California fossils. His article is a strong
argument for the Eocene age of the Tejon and incidentally it throws
considerable doubt on the accuracy of Mr Gabb's statements concerning
the species that occur in both the Chico and the Tejon.

Professor Jules Marcou§ and Dr C. A. White || have also referred the
Tejon, or division B, to the Eocene, and this view is now generally
accepted. While admitting its Tertiary age, both Dr White ^[ and Dr G.
F. Becker,** after studying the subject in the field, have stated their
belief that in southern California the Tejon, is only the upper part of an
unbroken series, the Chico-Tejon, in which the sedimentation as well as
the life was continuous from the Cretaceous into the Tertiary.

In the second volume of the Paleontology of California, published in
1869, Professor Whitney ff again summarized Mr Gabb's latest views on
the classification of the Cretaceous. Division B is named the Tejon
and considered to be the probable equivalent of the Maestricht beds.
Division ^1 is separated into three groups : the Martinez group, which
is doubtfully separated from the one next below ; the Chico group, which

♦Conrad's articles arc in Am. Jour. Conch., vol. i, 18G5, pp. 3G2-305; vol. ii, 1866, pp. 97-100, and
Am. Jour. Sci., vol. xliv, 1867, pp. 376-377. Gabb's replies may lie found in Am. Jour. Conch., vol. ii,
pp. 87-92; Am. Jour. Sci., vol. xliv, 'pp. 226-229, and Proc. Cal. Acad. Nat. Sci., vol. iii, 1867, pp. 301-
306.

fProc. Cal. Acad. Nat. Sci., vol. iii, 1867, p. 302.

JProc. Acad. Nat. Sci. Phi la., 1882, pp. 195-214 ; Contributions to Tertiary Geol. and Paleont. of flic
United States, 1884, pp. 102-117.

g Bull. Soc. Geol. de France, tome xi, 1883, pp. 417-435.

|| Bull. 15, U. S. Geol. Survey, 1S85, pp. 11-17; Bull. 51, 1889, pp. 11-14; Bull. 82,1891, p. 193.

U See references just given.

** Bull. 19, U. S. Geol. Surv., 1885.

+t Pages xiii and xiv.

248 T. W. STANTON SHASTA AND CHICO FAUNAS.

is correlated with the Upper Chalk or Lower Chalk and, it is thought,

may prove to be the equivalent of both, is said to include all the known
Cretaceous of Oregon and of the extreme northern part of California and
the coal-hearing beds of Vancouver island; and the Shasta group, pro-
visionally formed to include a series of beds of different ages below the
Chico. According to Whitney "it contains fossils, seemingly represent-
ing ages from the Gault to the Necomian, inclusive. . . . Few or
none of its fossils are known to extend upward into the Chico group."

Work of the Canadian Geological Survey. — In 1871 the geological survey
of Canada began the work in British Columbia which has contributed
greatly to our knowledge of the Mesozoic formations of the Pacific coast.
It is beyond the scope of this paper to consider the detailed geologic
description of the Cretaceous on Vancouver and Queen Charlotte islands
and the mainland of British Columbia, as given by Mr James Richard-
son* and Dr George M. Dawson. f

These reports have shown that the Cretaceous attains thicknesses of over
5,000 feet on Vancouver island and of about 13,000 feet on Queen Char-
lotte islands. The invertebrate fossils from both these areas have been
described and fully discussed by Mr J. F. Whiteaves.| The most recently
published conclusions of this author are that the larger part (divisions
C, D, and E) of the Queen Charlotte islands section is the equivalent of
the Shasta formation, and that the same horizon is represented in the
northern part of Vancouver island and at several localities on the main-
land of British Columbia; that the beds of the Nanaimo and Comox
coal fields on the eastern coast of Vancouver island are more recent and
referable to the Chico formation, and that none of these beds are older
than the Gault. Previously Mr Whiteaves had expressed the opinion
that the Shasta formation and its equivalents in British Columbia should
be separated into two formations, referring the older beds, which are
especially characterized by an abundance of Aucella, to the Necomian
and the upper portion to the Gault; but additional collections showed
such a blending of the faunas that they could not be separated and this
view was abandoned.

* Report on the coal fields of the east coast of Vancouver Island : Geol. Surv. Canada, Rept. of
Prog. 1871-72, pp. 73-loit; Rept. on the coal fields of Vancouver and Queen Charlotte Islands : Ibid.,
1872-'73, pp. 32-65.

f For example— Report on the Queen Charlotte Islands: Ibid., 1878-79, pp. 1-101 B; On a Geologi-
cal Examination of the northern Part of Vancouver Island : Ann. Kept. Geo). Survey < 'anada, 1886,
pp. 1-107 B ; On the earlier Cretaceous Rocks of the northwestern Portion of the Dominion of
Canada : Am. Jour. Sci., vol. xxxviii, 1889, pp. 120-127.

t Geol. Survey Can. : Mesozoic Fossils, vol. i, pt. 1, Invertebrates from Queen Charlotte Islands,
1876; pt. 2, Fossils of the Cretaceous Rocks of Vancouver, 1879; pt. 3, Fossils of the coal-bearing
deposits of Queen Charlotte Islands, 1884. See also Trans. Roy, Soc. Canada, vol. i, 1882, sec iv,
pp. 81-86, and Cont. to Canadian Paleont., vol. i, pt. 2, 1889.

USE OF DILLER'S COLLECTIONS. 249

White's Classification of the California Cretaceous. — DrC. A. White, whoso
work on the Cretaeeous of California has already been referred to, also
recognized two divisions in the Shasta, to which he gave the local names,
Knoxville and Horsetown beds, although he believed them to be closely
related ; and several species of the Horsetown fauna were afterward
found associated in the same strata with Aucella, the characteristic fossil
of the Knoxville beds, near Riddles, Oregon.* It may therefore be
regarded as established that the Knoxville beds should not be considered
distinct from the remainder of the Shasta formation, although they may
usually be recognized by the great abundance of Aucella, a fossil that
seems not to range into the upper part of the scries.

The great apparent difference in the faunas of the Shasta and the < hico
formations at the localities studied by him led Dr White to believe that
there is a break between these two formations, representing a great time-
hiatus.f although they are apparently conformable. The list of species
assigned to each formation by Mr Gabb also seemed to justify this belief,
but the sequel will show that the stratigraphic position and the vertical
range of many of the species were very imperfectly known until quite
recently.

Relation of Shasta and Chico Faunas.

Identity of Fauna* indicated. — Various members of the United States
Geological Survey working in California and Oregon during the last few
years have from time to time made small collections of Cretaceous fossils
that have been submitted to Dr White for examination. The largest of
these collections was received from Mr J. S. Diller in 1889, and was
assigned to me for study and identification, under the direction and
supervision of Dr White. The collection embraced small lots of fossils
from about seventy-five different localities in northern California and
southern Oregon, the most of which are in the valley of Sacramento river.;};
There were usually only a few species of fossils from each locality, as they
were collected by the geologists in connection with other field-work and
without any attempt at making exhaustive collections. The fossils were
identified and those from each locality were, so far as practicable, assigned
to tbe Shasta or to the Chico-Tejon, in accordance with the distribution
of species in those formations given by Mr Gabb. But some of the locali-
ties seemed to show a mixture of Shasta and Chico species, and when

*See G. F. Becker, Notes on the early Cretaceous of California and Oregon : Bull. Geol. Soc. Am.,
vol. 2, 1891, pp. 204-205.

fSee Hull. U. S. Geol. Survey, numbers 15, 22, 51 and 82.

J For description of the geology of this region and further discussion of the paleontology see Mr
Piller's paper, this volume, pp. 205-224.

250

T. W. STANTON — SHASTA AND CHICO FAUNAS.

Mr Diller plotted all the localities on the map those that were assigned
to different horizons were seen to be inexplicably mixed. Mr Diller at
that time suggested that the two faunas were more closely related than
had hitherto been supposed, but the evidence; did not then seem to be
conclusive.

Local Lists of both Faunas from northern California. — During the past
held season Mr Diller had considerable collections made at Horsetown,*
Shasta county, California, and at Texas springs, less than two miles east
of Horsetown. These fossils, which have recently been studied, gave
unquestionable proof of the blending of the Shasta, and Chico faunas.
M i- 1 >iller says that the beds from which the fossils were collected at thes< i
two localities are of no considerable thickness. Besides the nature of
the matrix, the state of preservation of the fossils and the manner in
which the species are commingled on hand specimens, all indicate that
the entire collection came from the same horizon. I have therefore listed
the fossils from both localities together, as follows :

u
u

^Ammonites hoffmanni, Gabb.
* Ammonites breweri,
*Diptychoceras Isevis,
Ancyhceras (?) lineatus, "
*Belemnites impressus, "
Liocium punctatum, "

*Lunatia avellana,
Gyrodes.

Fusus aralns, Gabb.
*Anisomyon meekii, Gabb (?)
Scalaria albensis (?), D'Orb., Whit-
eaves.
Actseonina califomica, Gabb.
Cinulia.

f Ringicula varia, Gabb.

*Ringinella polita, "

fPanopsea concentrica, "
\Cucullasa truncata,
\Nemodon Vancouver ensis, Meek.

jTri(/onia sequicostata, Gabb.

'I'Trii/oiiia leana,

Trigonia.

fPecten operculiformis, Gabb.

f Thetis annulata (Gabb) = Cardium

(Lsevicardium) annulatum.
'I'Corbula traskii, Gabb.
fMytilti* tjioidraius, Gabb (?)
Mytilus lanceolatus, Sowerby.
\Leda translucida, Gabb.
*Pleuromya laevigata, Whiteaves.
~\Tellina hoffmanniana, Gabb.
fTellina mathewsonii, "
\Maetra ashbtirneri, "

fChione varians, "

fMeekia radiata, "

fMeekia navis, "

fMeekia sella, "

Rhynchonella.

*Mostofthe localities mentioned are shown on the sketch map prepared by Mr J. S. Diller,
forming plate 1, page 205, of this volume.

*fThe species belonging to Mr Gabb's Shasta fauna arc marked with an asterisk (*), those
belonging t<> t h> ■ < h ieu u i 1 1 » an obelisk (t). The others have not been positively assigned to either
horizon.

Mr Gabb's nomenclature is used, in most- cases without revision, throughout this paper.

HULEN CREEK AND ONO COLLECTIONS.

251

Of the 36 species in this list, the Paleontology of California gives 8 as
coming from the Shasta and 18 from the Chico, while 2 of the others are
doubtfully referred to the former and 2 to the latter. At least 12 of these
species are also represented by identical or very closely related species
in the Queen Charlotte islands (lower shales), and 7 are similarly repre-
sented in the equivalent of the Chico on Vancouver island.

It will be remembered that Horsetown is a typical and well known
Shasta locality, and that the types of two of Mr Gabb's species were
obtained there.

Many of Mr Diller's localities for fossils are on Cottonwood creek and
its branches, a few miles southwest of Horsetown. It will be instructive
to group together some of these places and consider the fossils that were
obtained from them. On Hulen creek, and near its mouth on Cotton-
wood creek, the following were collected :

Ammonites bated, Trask.
Ammonite* hoffmanni, Gabb.
. Immonites remondi,
Turritella.
Cytherea.

Trigonia evansana, Meek.
Trigonia tryoniana, Gabb.
Nemodon Vancouver ends, Meek.
Cucidlsea truncata, Gabb.
Pecten opercuHformis, "

This collection adds two Shasta and two Chico species to the Horsetown
and Texas springs list.

At and about Ono, California, mostly within a mile of the village, the
following species were obtained :

Ammonites bates!, Trask.
Ammonite* breweri, Gabb.
Ammonite* hoffnianni, "
. Immonites remondi,

Martesia clausa, Gabb.
Tu/rnus plenus, l'~
Pleuromya laevigata, Whiteaves.
Trigonia leana, Gabb.

Ammonites (Phylhceras) ramosus, Trigonia sequicostata,

(?)

Meek.
Ancyloceras remondi, Gabb.
Belemnites impressus,
Cinulia mathewsoni,
Lunatia avellana,
J'oln m ides diode mil,
Ringinella polita,
An eli nra.
Nerinsea maudensis, Whiteaves.

a

a
u

a

Trigonia evansana, Meek.

Nemodon vancouverensis, "
Plicatula variata, Gabb.
Pecten open-id i form is, '*
Avicula mucronata, Whiteaves.

Pinna.
Ostrea.
Eriphyla.

Most of the species in this list not contained in the preceding ones were
originally described as from the Shasta.

252 T. W. STANTON — SHASTA AND CHICO FAUNAS.

Localities at Gas Point post office and on Roaring river, not far dis-
tant, yielded the following:

Ammonites chicoensis, Trask.

Turriteila seriaMm-granulata, Gabb, not Koemer.

Nucula truncata, Gabb.

On the Cold fork of Cottonwood creek the following collection was
obtained :

Bacidites chicoensis, Trask. Cucullsea truncata, Gabb.

Belemnites impressus, Gabb. Pecten traskii, " (?)

Neptunea hoffmanni, " Ostrea.

Nucula truncata, " Terebratetta obesd, "

Two of these species are common to Horsetown and Texas springs.

Going a few miles farther southward, the first important localities are
on Elder creek, on the line of one of Mr Diller's measured sections. Near
Lowry's and at other places farther westward specimens of Aucella piochii,
Cod))), were obtained, while a higher horizon about two miles east of
Lowry's yielded the following species :

Gyrodes excavata (Mi chelin), Whit- Venus lenticularis, Gabb.

eaves. Tellina parilis, "

Lunatia. Tellina ashburneri, ''

Anchura californica, Gabb. Cucullcea truncata, "

Dentalium stramintum, " Astarte conradiana, " (?)

Thetis annulata, ■ " Pecten operculiformis, "

Chione various, " Avicula.

This lot shows a greater difference than any of the others, although it
contains at least four species enumerated from other localities above
given.

Sufficient evidence has therefore been presented to show that all the
species from the several localities mentioned very probably belong to
one fauna.

Near Redding, on Sacramento river, a large number of species were
collected, many of which were not obtained at any of the above localities,
but the presence there of such forms as Cucullsea truncata, Trigonia evan-
sana, Pecten operculiformis, Corbula traskii, etc, make it probable that the
beds belong to the same continuous series, though they may represent a
somewhat higher horizon.

Collections from several localities in Oregon that have always been
referred to the Chico formation, such as Crooked river. Siskiyou moun-

ABANDONMENT OF THE MARTINEZ GROUP. 253

tains, Ashland, and several places in Jackson county, indicate about the
same horizon as that of the bed at Horsetown.

Original Localities of Chico Fossil*. — In the second volume of the Pale-
ontology of California there is a " Synopsis of the Cretaceous invertebrate
fossils of California/' giving a complete list of the species then known,
with the localities at which they had been obtained. For convenience
in making comparisons I have made a list of the species reported from
each locality there mentioned. Leaving out of consideration the locali-
ties from which only from one to three species are reported, there are
sixteen localities from winch Chico fossils were obtained. An examina-
tion of the faunal lists from these places show that eleven of them may
be referred without question to the Shasta-Chico fauna as represented at
Horsetown and in the neighborhood of Cottonwood creek. These local-
ities are: Benicia, Cottonwood creek, Crooked creek of the Des. Chutes
(Oregon), Curry's. Jacksonville (Oregon), Martinez, mount Diablo, Ores-
timba, Pacheco pass, Siskiyou mountains and Tuscan springs. The
other five localities, viz, Chico creek, Cow creek, Folsom, Pence's and
Texas Flat, yielded a greater proportion of species not contained in Mr
Diller's collections from Shasta county, but there are several well marked
Horsetown species reported from each of these localities ; and they are
all so intimately related to the other Chico localities by means of species
held in common with one or more of them that they cannot be regarded
as belonging to another fauna.

The Martinez group of Gabb has long since been abandoned as insep-
arable from the Chico ; and. as Mr Diller has shown in his paper on the
Cretaceous and early Tertiary deposits of this region,* the Wallala for-
mation probably also belongs in the same series.

Faunas of Queen Charlotte and Nanaimo Formations.

Correlation of Queen Charlotte Formation with the Shasta. — The correla-
tion of the Queen Charlotte formation (divisions C, D and E oi Dr Daw-
son's section) with the Shasta has already been mentioned in speaking
of Mr Whiteaves' work. The additions now made to the Horsetown
fauna materially increase the number of species that occur in both the
Shasta and Queen Charlotte formations. It should lie stated, however,
that several genera of ammonites found on Queen Charlotte islands and
not yet seen in the Shasta suggest a somewhat earlier period for the bed
in which they occur. It would simplify the matter if it could be proved
that these ammonites came from a lower horizon. It is worthy of note

*Ante, pp. 205-224.
XXX!VIII— Bull. Geol. Soc. Am., Vol. 4, 1882,

254 T. W. STANTON — SHASTA AND CHTCO FAUNAS.

in this connection that the upper shales and sandstones, or division A
•of the Queen Charlotte section, contain Inoceramus problemalicus, Schloth.,
a species that is characteristic of the Colorado formation in the Rocky
mountain region and is not known to range higher than the Turonian
in Europe.

Correlation of Nanaimo Beds with the Chico. — The correlation of the
Nanaimo.beds on Vancouver island with the Chico formation, taken in
connection with the facts already given, implies that these beds are more
closely related to the Queen Charlotte formation than has been supposed,
and I think that a comparison of the faunas found in the three regions,
California, Vancouver and Queen Charlotte, will give evidence of this
relationship. The principal facts that seem to he opposed to this con-
clusion arc that some of the species of B 'acuities and of Inoceramus found
on Vancouver island are apparently closely related to species in the
Montana formation of Nebraska. Colorado and elsewhere in the interior
region, and that the plants found in the Nanaimo coal held are said to
be of upper Cretaceous types.

With the possible exception of the species just mentioned and a few
others that have little diagnostic value, it is doubtful whether any of the
species of the Shasta-Chico fauna occur in the upper Cretaceous beds
east of the Rocky mountains.* The ammonites nearly all belong to
genera that are not found in the upper Cretaceous of the interior region
and differences almost as great might be pointed out in other classes of
mollusks.

These facts may readily be explained by supposing that the faunas
lived contemporaneously in different oceans separated by a long conti-
nental area, but they would also be equally ay ell explained if it could
be proved that they were not strictly contemporaneous.

The Shasta-Chico Fauna compared with the Fauna of the Black-
down Beds.

Mr Whiteaves has correlated the Queen Charlotte formation with the
Gault, and as confirmatory of this reference it may be of interest to give
the results of the comparison 1 have made with one of the English Cre-
taceous faunas.

In Sowerby's "Mineral Conchology " 4G species of Cretaceous fossils
are described from the Blackdown beds of Devonshire, England. These
beds have usually been referred to the Gault, though some authors now
regard them (at least in part) as „ representing the lowest beds of the

*See Dr C A. White's statement on this point in Bull. 15, U. S. Geol. Surv., pp. 27-29.

CORRELATION WITH EUROPEAN DEPOSITS.

255

Cenomanian. Of the 46 species figured by Sowerby as coming from
Blackdown, at least 23, or one-half of the entire number, are represented
in the Shasta-Chico fauna by closely related species. These include such
well marked forms as —

From Blackdown-

Astarte striata.

Cuculhva costellata,

Cucullsea fibrosa.

Exogyra conica,

Mytilus edentulus.
Mytilus lanceolatus

Thetis major.
Thetis minor.

Trigonia aliformis.

Trigonia dxdalca.

Trigonia spectabilis

Turritella granxdata.

Represented in California by —

Eriphyla umbonata. (?)
Nemodon vancouverensis.
( 'ucullsea truncata.

Exogyra, parasitica.

Mytilus lanceolatus. (?)

Thetis annulata.

Trigonia evansana.

Trigonia leana.

Turritella seriatim-gra n idata. (?)

In addition to these the Blackdown beds contain a number of species
belonging to the Venerida1 and Aporrhaidse, both of which groups are
well represented in the Shasta-Chico fauna. In fact, so far as can be
judged by figures and descriptions, the whole fauna of the Blackdown
beds, if it had been found in the western part of the United States, would
be referred to the Shasta formation and about to the horizon of the
Horsetown beds.

Whether the Chico beds above the fossil-bearing Horsetown horizon
represent all the rest of the upper Cretaceous remains to be determined.
The close relationship of their fauna to that of the underlying beds which
has been compared with the Gault and Cenomanian, and its distinct-
ness from the upper Cretaceous faunas east of the Rocky mountains
representing the Turonian and Senonian of Europe seem to favor the
view that a large part of the upper Cretaceous series is absent from the
Pacific coast.

Conclusions.

' In view of all these facts, it seems to me that the exact relationship of
the Chico and Tejon formations and the extent to which their faunas are
connected must still be regarded as an open question that can be solved
only, if at all, after exhaustive collections have been made from both
formations and thoroughly studied.

256 T. W. STANTON — SHASTA AND CHICO FAUNAS.

The specific conclusions reached may thus he summarized : There is

no fauna] break any where in the entire series of strata- that have been
referred to the Shasta and Chico formations. Certain portions of the
series are characterized by the abundance of particular species, e. g.,
AuceUa in the lower beds and several species and genera of ammonites
in the Horsetown division ; but these sub-faunas are so bound together
by connecting species that they cannot be regarded as really distinct,
and I have therefore adopted Mr Diller's suggestion and called the whole
the Shasta-Chico fauna. The age of this fauna, or at least of the portion
found in the Horsetown beds, seems to be not more recent than the
Cenomanian.

BULL. GE10L. SOC. AM

@sooo' Prominent Bed Rock fiiUs

/Approximate course of Neocene ChajineC(rem.aiRLng)

VOL. A. 1892. PL. 5.

no'jo'

t20*

RECENT AND NEOCENE DRAI NAGE SYSTEMS v

Of The

Yuba and American Rivers,

Sierra Nlvada, California.

ao miles

-j

3<)

110 JO'

/ rfpproAimate course of Neocene Channet (eroded)
£tQorrect position and eleratton of Neocene Channei

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA
VOL. 4, PP. 257-298, PLS. 5-9 JUNE 19, 1893

TWO NEOCENE RIVERS OF CALIFORNIA

BY WALDEMAR LINDGREN

(Presented before Ihc Society December SO, 1892)
CONTENTS

Page

Introduction 258

Review of Literature 25! »

< )l (servations on Method of "Work 262

( Outlines of Geologic History 263

Topography 263

Condition of the Sierra Nevada before and during the Gravel Period. 264

The volcanic Period 266

The Neocene Yuba River 268

The main River 268

From the Sacramento Valley to French Corral 268

The Nevada City and Grass Valley Channels 269

French Corral to North San Juan 270

North San Juan to Badger Hill 270

The North Fork ] 271

The Middle Fork 271

Badger Hill to North Bloomfield 271

North Bloomfield to Snow Point 272

The Derbec Channel 27:;

The Forest City Channel 27:;

Snow Point to Milton 271

Milton to Meadow Lake 276

The South Fork 277

Badger Hill to Dutch Flat 277

The Channel at Dutch Flat 282

The Liberty Hill Tributary ' 282

The Channel between Alta and Shady Run 283

The Neocene American Liver 284

The South Fork 284

From the Sacramento Valley to Diamond Springs 284

Diamond Springs to Newtown 285

Newtown to Pacific House 286

The North Fork 287

From the Junction to Jones Hill 287

Jones Hill to Bath 288

The Iowa Hill Channel 289

X XXIX— Bull. Gkol. Sue. Am., Vol. 1, 1892. (-57)

25S W. LINDGREN — TWO NEOCENE RIVERS OF CALIFORNIA.

Page

Bath to Ralstons 290

The Damascus and Last ( lhance Tributaries 291

< feneral character 291

From the Ralston Mine to Summit Valley 291

The lower Course 292

The Duncan Peak Tributary 293

The Canada Hill Tributary 293

The upper Course 293

Discussion of < rrades -"••I

( inclusions -"-IS

Introduction.

Tlie investigations of the United States Geological Survey in the Gold
belt of the Sierra Nevada, carried out under the direction of Dr (i. V.
Becker, with whose consent this paper is published, have included the
geologic mapping of the country on topographic contour maps on the
scale of 1 : 125,000, or about two miles to the inch. During the course of
this mapping much information has been gained concerning the Neocene
river channels, now largely covered by deep volcanic flows or cut away by
subsequent erosion. The auriferous character of the accumulated gravels
gives, as is well known, great practical importance to these channels.

A large number of the productive Neocene gravel deposits occur in the
watersheds of the present Yuba and American rivers, which were in-
cluded in the area assigned to the writer. It has been found that these
deposits are parts of two river systems which in a general way corre-
spond to the two modern rivers now draining the same territory.

It is the purpose of the present paper to indicate buiefly the direction
of the principal forks of the Neocene Yuba and American rivers, to give
a more accurate idea of the Neocene topography within this district,
and to call further attention to certain channels which might prove re-
munerative if opened by mining operations. The continuity of sonic
of these can be asserted and their approximate position indicated. It is
not proposed in this place to enter upon any elaborate discussion of the
many and interesting questions connected with the accumulation of the
gravels, nor is it the intention to describe in detail the often complex
channel systems of any particular region*

*The term "Neocene" has been used, < sistently with the nomenclature adopted by the Sur-
vey, in preference to " Pliocene." The N ;ene comprises tin- Miocene .-mil Pliocene periods of

the Tertiary era, between which, in the Sierra Nevada, no definite line can be drawn. It is, in. I I,

very probable thai the first period of erosion, the gravel period mm. I tin- volcanic period repre-
sent :i large pari of the time between the later Creti us and tin- later Tertian . bul there is no

definite floral or faunal evidence t<> support this.

work of whitney, le conte and others. 250

Review of Literature.

For the first accurate information as to the geologic character and
occurrence of the gravel beds we are mainly indebted to the former state
geological survey of California under Professor J. D. Whitney. His
volume on the Auriferous gravels * containing, besides his own extensive
observations, the detailed notes of W. A. Goodyear and Professor W. H.
Pettee, marks an epoch in the development of our knowledge of these
Neocene deposits. The observations recorded in this book are in general
accurate and trustworthy. The "review" at the end of the volume by
Goodyear appears, in the light of later investigations, as very excellent
indeed, and. while one may differ from some of his conclusions, it must
be acknowledged that his views of the channels and of the general
topography of the country over which they flowed are confirmed by
more detailed and extended surveys. To these investigators belongs
the credit of having established the fluviatile character and the age
of the deposits, of having recognized the two important river sys-
tems corresponding to the present Yuba and American rivers, and
of having begun to outline the old drainage lines. Professor Whitney
concludes that the Sierra Nevada has not undergone any important
changes as to the general level and the grade of its channels, and that
the carving of the canyons subsequently to the gravel period was prin-
cipally caused by climatic changes.

In 1886 Professor Joseph Le Conte published a paper on "A post-
Tertiary elevation of the Sierra Nevada shown by the river beds," f in
which no new observations were recorded, but which gave an impetus to
the investigation by the introduction of a new theory, which, however,
had already been suggested by Mr G. K. Gilbert in 18834 In subse-
quent papers Professor Le Conte has further elaborated his views, § and
in 1891 he published a paper on the " Tertiary and post-Tertiary changes
of the Atlantic and Pacific coasts," || in which is found a concise state-
ment of his present opinion, which is quoted in full:

"The Sierra was formed, as we now know, by lateral crushing ami strata-folding
at the end of the Jurassic. But during the long ages of the Cretaceous and Tertiary
this range was cut down to a very moderate height, with gentle slopes eastward

*.I. D. Whitney: "The Auriferous Gravels of the Sierra Nevada of California." Memoirs of tin.'
Museum Comp. Zoo!., vol. <;, no. l, 1880.
t Am. .lour. Sei., 3d series, vol. xxxii, 1886, \>. 167.
{Review of Professor Whitney's "Climatic Changes;" Science, vol. i, 1883, pp. 141-142, 169-173,

an. I 193-195.

gForamore extended review of the literature regarding this subject the reader is referred to
Mr II. W. Turner's "Mohawk Lake Beds." Bull. Phil. Soc. Washington, vol ix, April, 1891, pp.

385-410,

II Bull. Geol. Soc. Am., vol. 'J, pp. 323-330.

260 W. LINDGREN — TWO NEOCENE RIVERS OF CALIFORNIA.

and westward from a crest which was probably situated along a line just above the
Yosemite and Hetch-Hetchy valleys, for there the erosive biting into the granite
axis seems to be deepest. The rivers, by long work, had finally reached their base-
levels and rested. The scenery has assumed all the features of an old topography,
with gently flowing curves. The continental elevation" — previously described in
the same paper — " of the Pliocene did not greatly affect the river slopes of this part.
At the end of the Tertiary came the great lava streams, running down the river
channels and displacing the rivers; the heaving up of the Siena crust-Mock on its
eastern side forming the great favdt cliff there and transferring the crest to the ex-
treme eastern margin; the great increase of the western slope and the consequent
rejuvenescence of the vital energy of the rivers; the consequent cutting down of
these to form the present deep canyons, and the resulting wild, almost savage,
scenery of these mountains."

Mr J. S. Diller, who has studied the geology of the northern end of the
Sierra Nevada north of the fortieth parallel, holds similar views as to the
age and elevation of the range. They were first set forth in his " Notes
on the Geology of northern California,*'* which, however, does not in-
clude any detailed discussion of the Tertiary river deposits on the west-
ern slope. His conclusions may he best stated by quoting from a later
paper on the " Geology of the Lassen peak district: "f

"During the whole of the Cretaceous and the Tertiary the great belt of country
lying east of the present Sacramento valley, embracing the region now occupied by
the Sierra and a large portion of the Great Basin, was above the sea, and subjected
to great degradation, which reduced it almost to its base-level of erosion. This
gentle plain swept westward toward the ocean directly across the site of the present
Sierra. That the north end of the Sierra country was a lowland during the Miocene,
as already shown, is rendered perfectly evident by the character of its flora; and
the relation of the Miocene conglomerate to the eastern escarpment north of Honey
lake is such as to demonstrate that during the Miocene the Sierras were not yet in
existence. Similar conditions continued through the Pliocene, for the Pliocene
gravels on the western slope of the Sierras were evidently deposited while its in-
clination was very gentle, before the Sierra region had attained any considerable
elevation, and apparently also while it was yet a part of the Great Basin platform.
* * * The faulting, by means of which the Sierra Nevada range was separated
from the Great Basin platform, took place, in a geologic sense, very recently. The
eastern escarpment of the range, at least in its northern portion, was evidently
formed after the conclusion of the volcanic activity in its immediate vicinity."

Since the above was written, Mr Diller has published a paper on the
-• Geology of the Taylorville region,"^ in which he shows the Taylorville
fault to be an overlhrust instead of a normal fault, as he had previously

supposed. This change necessarily modifies his earlier views to some
extent.

♦ Bulletin 33, U. S. Geol. Survey, L886.

t Eighth Ann. Rep. V. 8. Geol. Survey, 1889, p. 128.

| Bull. Geol, Soc. \m., vol. 3, p, 369.

WORK OF BECKER, BEOWNE AND HANKS. 261

Dr (i. F. Becker, in his paper on '^Tlie Structure of a portion of the
Sierra Nevada of California,"* considers the range to have existed as
such during the Tertiary. From the analysis of the extensive fissure
system discovered by him he draws the c melusion that no important
tilting of the Sierra has taken place at or since the post-Miocene disturb-
ances, but that the western slope of the range has been increased by dis-
tributed faults along these systems.

For the next and very important contribution to the actual knowledge
of the Neocene channels one is indebted to Mr Ross E. Browne, who gave
the results of his careful and detailed survey of the Forest Hill divide in
the tenth annual report of the state mineralogist of California, 1890,
pages 435-465 (with maps). Mr Browne's work includes an accurate
topographic mapping of the contacts of the Neocene deposits and Hows
with the bed-rock, surveys of all tunnels and mines, and determination
of elevation of all important points. It is the first work of its kind, and
stands as a model for the many similar ones which it is hoped the future
will bring forth. It is gradually beginning to be recognized that de-
tailed surveys are indispensable when works of such magnitude and
cost are contemplated as the opening of important gravel channels.
Both on the Forest Hill and Placerville divides large sums of money have
been lost by neglecting a sufficiently extended topographic and geologic
survey of the region in question.

To Mr Browne belongs the credit of having first distinctly recognized
the different systems of later channels (channels of tire volcanic period)
as contrasted with the older pre-volcanic drainage system. In ( Jood year's
notes from Forest Hill and Placerville the existence of such channels
is, however, plainly implied. Mr Browne also gives a diagram showing
the grades of the Neocene rivers with reference to the longitudinal axis
of the Sierra with the view of ascertaining whether tilting of the range
can be recognized in the grades of the Neocene channels. f He thinks
more data are needed, but " that the evidence, as far as it goes, is against
any considerable increase in the slope of the Sierra flank — decidedly
against an increase large enough to account per se for the two thousand
feet deeper cutting of the modern river." In the same report Mr John
Hobson has carefully described and mapped the Iowa, Hill divide in a
similar detailed way.J

Mr Henry G. Hanks§ still appears to maintain a glacial or partly
glacial origin of the gravels. I fear that in upholding this theory he is
contending against very heavy odds. No evidence whatever of the ex-

* Bull. Geol. Soe. Am., vol. 2, pp. <>1 and 7:;.

fOp. eit,, p. 445.

| Op. eit., p. 419.

I Mining and Scientific Press, San Francisco, April 5, 1890, and following numbers.

262 \V. LINDGREN — TWO NEOCENE RIVERS OF CALIFORNIA.

istence of Neocene glaciers has thus far been met with in the highest
part of the range in this Latitude; nor is it likely, in view of the char-
acter of the Neocene flora high up on the flank of the range, that such
evidence will he found.

Observations on Method ok Work.

The help of a contour map is almost indispensable in order to ohtain
a correct idea of the Neocene drainage and topography.*

Each point of the contact lines between the bed-rock ami the super-
jacent Neocene gravels or volcanic flows necessarily marks a point on
the old surface of the region such as it was before hidden under Tertiary
accumulations. A great number of these contact lines are usually ex-
posed b}^ the canyons and creeks eroded since the close of the Neocene
period, and each of them affords a section through a part of the Neocene
surface. It will easily be conceded that if the elevation of a sufficient
number of points on the contact lines were known, a contour map might
be constructed of the Neocene surface, showing the topography and
elevation above the sea, provided that no change in level or tilting had
taken place in the interval. Even in such a case the map would he
valuable as showing the relative topography, and if the existence and
amount of the disturbance of the old surface could he ascertained by
other means a correct map referred to the old sea level might he obtained
from it. The bed-rock points that have been above the surface of the
lava flows since the end of the Neocene — and there are many of them in
the Gold Belt region — have often suffered a degradation difficult to
measure, but probably in most cases not large. The flat tops of many
of them show them to have formed a part of the Neocene surface, and
the erosion, while scoring and furrowing their flanks, has not yet reached
their summits.

Many of the topographic features of the Neocene region may be directly
read on the contour maps on which the geologic areas are outlined.
If in a certain vicinity all the contact lines between lava and bed-rock
run practically parallel with the contours and at the same elevation, the
conclusion is easy that the Neocene deposit rested on a horizontal surface.
provided no tilting has taken place since. If, again, the contact lines
cross the contour lines in an irregular way and at considerable angles, the
old surface was broken and irregular; with a sufficient number of contacts

* Tin- part of the < told licit here under consideration Ins been mapped on tin- scale <>t l : 125,000, or
:ii ii mi two mill's to the inch, with a contour interval of one hundred feet. It comprises the Smarts-
vi lie, Colfax, Truckee, Sacramento, Placer ville, and Pyramid Peak sheets, and the topography has

1 n executed by Messrs h. M. Wilson, A. F. Dunnington, B. 11. Mc Kee, and M . E. I louglas under

tin' charge pf Professor A. 11. Thompson. The geologic maps of the larger pari of tic area are
finished and are now ready for publication. The Sacramento atlas short bas just been printed.

ULL. GEOl. SOC. AM.

1Z 'J:

nr

—

InJitn.H

iSic&rd

Tinxb. .
100' **K^_^fi/voonty

113'

Wa.Uup£7F**Littyor}(

aZndian.4 H.
I bo ' fir i est)

I Iowa Hill.
\ (nearly level)
aWiscons. H.

Atyf/s

'9

fan'kee.Oimj

/* sf^Dg rJa ntlUt.

VOL. 4. 1802. PL. 0.

"« ~~°Bl«cksmithFlit

teun Gulch.

tiuttyr/

i * <*< '^

/oo

"A/atvt

Neocene Yuba and American Rivers,

Sierra Nevada, California.

» i 1 i « ) "J i3 ■

\
*0 miles

V

fZC'jo'

w. fegjhga

\

.'2 J

SOUKCES OF ACCOMPANYING ILLUSTRATIONS. 2G3

the genera] drainage system may be made out. In the case of an old
valley running across a recent creek or canyon, the angles of the contact
lines with the contour lines on the opposite sides of the present gorge will
easily and directly indicate the ancient trough.

The accompanying map (plate 5) is reduced from atlas sheets of the
United States Geological Survey. The elevations are partly taken from
the very reliable observations of Messrs Pettee and Goodyear, partly
from the maps of the United States Geological Survey, supplemented for
short distances by my own aneroid determinations, and partly also from
the surveys of Mr Browne. The channels where obliterated by erosion
are marked by dotted lines; where remaining though generally hid-
den under volcanic masses, by heavy black lines. It must be under-
stood that in both cases the indicated position is only approximately
correct and showing the probable course of the deepest depression.

The grades given in plate 6 are affected by errors in distance and eleva-
tion. The latter are believed not to be great, but the former are difficult
to ascertain. An attempt has been made in measuring the distance to
follow the probable curves of the rivers; nevertheless the grades are
probably all a little too steep on account of underestimating distances,
but thedill'crencesarenot, I think, large enough to be of much importance.

The sections in plates 7 and 8 are taken from maps used in the field on
the scale of 1 : 62.~>i K), or nearly one mile to the inch. In most cases it
has been found necessary to enlarge the scale to 3,180 feet to the inch :
only section L L is drawn on the scale of 6,360 feet to the inch. In all
case3 the vertical and horizontal scales are equal.

Outlines of Geologic History.

Topography. — In this latitude the Sierra Nevada has two summits,
separated by the Truckee valley and the deep basin of lake Taboo. The
western summit, whose peaks rise from 8,000 to 10,000 feet above the sea.
is also the divide between the Pacific and the Great Basin, while the
Truckee river, draining lake Tahoe, has cut a deep canyon through the
second or easterly summit on its way to the depressions of the Nevada
deserts; on the eastern side of lake Tahoe the last-named summit at-
tains even higher elevations than the principal divide. With the easterly
summit and its escarpment this paper does not deal.

On the Pacific slope, in the watersheds of the Yuba and American
rivers, one may roughly distinguish three provinces:

First, the foot-hill region, most frequently consisting of prominent
ridges of diabase and amphibolite. Many of them, in Neocene times,
projected boldly above the river beds, as shown, for instance, in the sec-

2G4 W. LINDGREN — TWO NEOCENE RIVERS OF CALIFORNIA^

tion A A. In this province the volcanic flows are not conspicuous. It
is probable that the higher parts of the foothill region remained above

them, and erosion to a great extent removed them from the lower parts.

Second, the middle slopes, consisting chiefly of more or less altered
sedimentary rocks, the auriferous slates. In this region the broad tables
of Neocene lavas have largely effaced the pre-volcanic topography.
Often, indeed, ridges of older rocks rise here also above the top of the
gently sloping volcanic table-land, but as a rule they arc not prominent.

Third, the region of high bed-rock peaks adjoining the divide, in which
the character of a table-land, frequently noticeable even here. bec< >mes
modified by prominent points of ante-Tertiary igneous and sedimentary
rocks projecting conspicuously above the level of the Neocene flows. A
glance at the map, on which only peaks of the older rocks are marked
with their elevation in numbers, will make clear this distinction. At
the divide there are many volcanic peaks, culminating in the extinct
volcanoes of mount Lola. Castle peak and others which exceed 9,000
feel in height. The elevations of these volcanic peaks are not given on
the map. Were the later volcanic masses removed along the divide the
lowest passes would still be about 7,000 feet high.

( 'ondition of the Sierra X< vada before and during the gravel Period. — From
the evidence accumulated it cannot be doubted that during the gravel
period or the later part of the Tertiary the Sierra Nevada in this region
formed a mountain range as distinct, if not as high, as at present. The
two Neocene rivers headed near where the corresponding modern rivers
begin now, in a region of lofty peaks and ridges. Their watersheds cer-
tainly did not extend further eastward than the first summit, and in fact
corresponded pretty closely with those of the modern rivers. On the
Truckee sheet, at least, the Neocene divide coincides very nearly with the
divide of to-day, and only unimportant changes can be noted. East of
the divide there was an escarpment of moderate slope, and which is now
exposed in many canyons to a height of 1,000 to 2,000 feet; it probably
was much higher than this, but below a level of from (},<>( )0 to 7. "(Hi feel
above the sea its slope is completely hidden under the immense accumu-
lations of lavas Lying between the two summits north of lake Tahoe.

The total height of this escarpment as it was before the eruption of
the Neocene lavas should perhaps be measured from the bottom of hike
Tahoe to the summit of the western divide, approximately 4,000 or 4,500
feet. There is, on the Truckee sheet, no evidence of any important post-
volcanic fault along the western summit, nor is there any decided evi-
dence that the steep eastern slope just mentioned represents a fault
formed shortly beforcor during the volcanic period.

This is illustrated by sections G G and L L (plate 7). .Many similar
ones could be selected from the Truckee sheet. In G G a contact be-

w

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THE EROSION AND GRAVEL ACCUMULATION. 265

tween granite and andesite along which the section is laid runs for many
miles nearly due eastward across the divide, thus exposing an excellent
profile of the Neocene surface. The high volcanic ridges of mount Lola
immediately northward are projected on the section. The slopes of the
flows are eastward and westward from the central vents of the old vol-
cano of Lola.

In L L a section is made on a smaller scale across the divide showing
the depression of the headwaters of the Neocene middle fork of the
American river, east of which rises the old divide at Granite Chief. The
river heads only a few miles northward and rises rapidly in this direction.

The decided slope eastward from < Iranite ( Lief should be noted. That
this slope was also that of the Neocene divide is proved by the contact
lines of the andesitic masses with the underlying older rocks. This line
is projected on the section from the ridges immediately north of it.

From the ragged country in the region of their sources the rivers
pursued their course down in broad valleys separate 1 by ridges which
even in the lowest foot-hills sometimes reached an elevation of a thousand
feet above the channels. The outlines of the ridges were usually com-
paratively gentle and flowing; still, slopes of ten degrees from the
channel to the summit were common and slopes as high as fifteen degrees
occurred in the eastern part of the Sierra. The character of a region of
old and continued erosion, commencing probably far hack in the Cre-
taceous period, is everywhere plainly evident. In the center of the deep
depressions is quite frequently found a deeper cut or " gutter," indicating
a short period of more active erosive power just before the beginning of
the gravel period. At this time, probably about the beginning of the
Miocene period, the streams became charged with more detritus than
they could carry and began to deposit their load along their lower
courses, especially at places favorably situated, as, for instance, along the
longitudinal valley of the South Yuba. Toward the close of the Neocene.
gravels had accumulated all along the rivers up to a (present) elevation
of about 5,000 or 6,000 feet; above this it is plain that erosion still con-
tinued in places with great activity and furnished some of the materia]
deposited in the lower parts of the streams. The coarse character of
much of the gravel and the often remarkable absence of tine sediments
in the beds point clearly to a somewhat rapid stream capable of carry-
ing off a great deal of silt, and the accumulations are probably due to
rapid overloading rather than to low grade of the rivers. The deep chan-
nels were filled and the gravels encroached on the adjoining slopes, where
they were deposited in broad benches. A maximum thickness of 500 feet
of deposits was attained on the South Yuba, and of from 50 to 200 feel in
the other parts of the lower rivers. En the lower and middle Siena some

XL-Bum,. Geoi,. Soc. Am., Vol.. 4, 1802.

266 W. LINDGREN TWO NEOCENE RIVERS OF CALIFORNIA.

of the rivers then meandered over floodplains two or three miles wide,
above which the divides of bed-rock rise to a height of several hundred
feet. In some instances low passes over divides were covered, and tempor-
rary bifurcation and diversion of rivers into adjoining watersheds occurre< I .
The volcanic Period. — At this time the first eruptions of rhyolite began
from the first summit, from the volcanic center of Castle peak, they
poured down the valleys, at first as molten flows, then as fine breccias
and tuffs, and, being mixed with detrital material on their way, they arc
finally found lower down as semi-volcanic sands, clays and gravels.
These beds of mixed volcanic and sedimentary character, usually fine-
grained and distinguished by a brilliant white color, have been collectively
distinguished under the name of rhyolitic beds, and merge into the tuffs
and massive rhyolites of the upper valleys. The rhyolitic flows usually
confined themselves to the valleys and only in some instances flooded
certain of the low passes. The maximum thickness of these flows near
the summit is one thousand feet, but it rapidly diminishes westward.
These masses of fine detritus flooded the lower slopes and compelled the
rivers to seek new channels, still, however, in general confined to the old
valleys. The waters at once began the work of cutting down in the
clave}- and sandy masses. Then the period of the andesitic eruptions
began, Dark-colored mud flows, at first sandy and clayey, again flowed
down the valleys ; the divides began to be covered. Again the rivers
were displaced and again they at once began their work of active erosion,
cutting down not only through the accumulated silt to their former
levels, but. wherever the intervals between the eruptions allowed it, down
through the gravels sometimes deep into the underlying 1ied-n»ek. In
some districts, especially on the American river, these intervolcanic
channels cut and destroyed again and again the older deposits, pursuing
a wholly independent course, although in general flowing in the same
valleys. They have exactly the same characteristics as the modern
rivers. It is important to note that they enable us to fix with accuracy
the relative date of the change from the conditions of the Neocene to the
conditions of to-day. Whatever causes produced this change, they
began to act at this time. The intervolcanic channels were of an ephem-
eral character; successive eruptive flows changed their direction, and it
is to be expected that there were, as shown by Mr Browne, several dif-
ferent systems of them. They occur principally in the watersheds of the
American river where the interval between the first and the lasl andesitic
flows seems to have been considerably larger than in the region of the
Yuba. Cement channels, as the intervolcanic channels are often called.
no doubt also occur in the latter, but as a rule they did not have time to
cut down far into the rhyolitic beds before they were Idled and replaced

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THE LAVA BEDS AND TUFFS. 267

by the last great andesitic flows. The intervolcanic channels, being no
part of a permanent and established drainage, are not described or
further discussed in this paper.

These last flows, coming down in rapid succession from the volcanoes
of Weber lake, of mount Lola, of Castle peak, and many others south-
ward, flooded everything and covered up the lower and middle slopes to
such an extent that only isolated peaks or ridges protruded above them_.
Their character is peculiar; they consist of a gray or brown tuffaceous
breccia, containing, in the foot-hills as well as in the high range, large,
usually angular, bowlders of andesite. They came down the slope as
successive mud Hows, setting soon to a hard and compact rock. Molten
andesitic flows are found in the lava-flooded valley between the two
summits, and also at some places west of the first summit, but they did
not extend far down the western slope.

The thickness of these flows ranges from over a thousand feet high up'
to fifty or one hundred feet down toward the plains, where they are
nearly always underlain by volcanic sands and conglomerates washed
down from earlier flows winch had not reached so far down.

The eruption of this tuffaceous breccia is assumed to close the Neocene
period, and its flows form an important horizon by means of which the
Neocene gravels may lie separated from the later Pleistocene accumula-
tions. The age of the flows is indicated by the numerous plant impres-
sions common in the clays of the rhyolitic beds, as well as in those of
the older underlying gravels, and which, as well known, distinctly point
to the Neocene period. Only rarely is there any difficulty experienced
in distinguishing the Tertiary from the Pleistocene gravels.

The length of the volcanic period may be roughly measured by the
depths of the " cement channels " on the Forest hill divide. They have
cut through about one hundred and fifty feet of loose detritus and, at
most, one hundred feet of solid rock — not much more than a twentieth
of the erosion since the close of the volcanic period.

There have been no andesitic eruptions of later date than those de-
scribed in the region now discussed, and the continuity of the last over-
whelming lava, Hoods can be traced, almost uninterruptedly in places,
from the plains of the great valley to the summits of the high Sierra,.

When the volcanic activity ceased * the rivers began to seek their final
channels, those of to-day. The general drainage was outlined by the

*An eruption of massive basalt occurred in some parts of the Sierra Nevada subsequently to the
andesitic eruptions and previously to the glaciation. In the region here considered only small
areas of this Pleistocene basalt are found.

Mr H. W. Turner has recently shown (Am Jour. Sci., 3d ser., vol. xliv, 1892, p. 455) the existence
of ii basalt antedating the andesite in the northern part of the Sierra Nevada. This curlier basalt
does not occur in the area described in this paper.

268 \V. LINDGREN — TWO NEOCENE RIVERS OF CALIFORNIA.

ridges of older rocks still rising above the Hows, and to them is to be
attributed the fact that the Neocene river system roughly corresponds to
the present one; but over the large stretches of volcanic tables the rivers
marked their new courses entirely independent of the older streams, now
following them, now crossing them in a most irregular manner.*

The Neocene Yuba River.
the main river.

Fromtln Sacramento Valley to French Coiral. At Smartsville, near Sacra-
mento valley, a stretch of channel three miles Long has been preserved.
Its character and grade are described in detail by Mr Pettee in the
"Auriferous gravels," pp. 379-383. At Sicards Mat, ahout two miles lower
down, on the northern side of the river, a fragment of the old channel
remains, and three miles further down, on the southern side of the Yuba,
the last trace of it is found, but it is not certain whether the elevation
given at the last place represents the lowest channel. From here on it
is buried under the more recent deposits of the great valley. It should
be noted, in this place, that the areas of auriferous gravels indicated
by Mr Pettee on the low rolling foot-hills west of Smartsville as Neo-
cene and below the volcanic flows are in reality Pleistocene and rest
on the andesitic breccia, and that they consequently have no signifi-
cance in tracing the Tertiary channel.

The gravels at Smartsville and Sicards Mat do not belong to the oldest
Neocene deposits, for they contain a considerable amount of andesitic
pebbles. They are, however, certainly Neocene, for at Smartsville they
are covered by that sheet of andesitic tuffaceous breccia which, in the
region under consideration, marks the close of the Neocene period. They
must represent the Neocene river in its lower course, for both north
and south of Smartsville rise bed-rock ridges, and this place affords
really the only outlet possible for the channels of the upper course of
the Yuba; the Neocene river broke through the harried of the great
diabase area of Yuba county in a valley or canyon of somewhat gentler
profile, hut almost as accentuated as that of the recent river. The ridges
on each side rise to a height of one thousand feet or more above the old
channel (see section A A). It might he objected that the channel at
Smartsville was deepened during the intervolcanic period of erosion,
and consequently no longer represents the bed of the prevolcanic river.

* In the region described postvolcanic faults are ran' : those found have seldom more than 1 •

15 feet throw. The Tertiary deposits would greatly facilitate the recognition of any such faults of
considerable throw, and I think the probability very slight that the slopes shown in the sections
are to any noticeable degree influenced by such postvolcanic disturbances.

THE LOWEE ANCIENT VALLEY. 269

This I do not think is compatible with the gentle curve made by the
bottom of the old channel. The intervolcanic erosion cut sharp, strep
canyons like those of to-day. The deepest "gutters"* in the Smarts-
ville channel might perhaps have been carved by it and it probably
swept away earlier accumulations of "white" or quartz gravel. From
Smartsville to French Corral there is only one wav which the Neocene
river could have followed, that of the present river canyon ; any other
way would necessitate extremely improbable and sudden changes of
grade. A scattered line of small deposits indicates that in all probability
the old river, near the mouth of Deer creek, received a tributary of which
one branch came from Nevada City and the other from Grass valley.

Grades :

Lowest point — Sicards Hat, 3-] miles, ('»<> feet per mile (?).

Sicards flat — Timbuctoo, If miles, 100 feet per mile.

Timbuctoo — Mooney flat,3 miles, 113 feet per milel Smartsville channel ).

Mooiiey flat— French Corral, 1" miles, 7* feet per mile.

The Nevada City and Grass Valley Channels. — In spite of the extensive
erosion west of Nevada City and Grass Valley there is pretty good evi-
dence that the channels of these places formed the old equivalents of
the present Deer creek and connected with the main Vuha river a short
distance above .Mooney Hat, three miles above Smartsville. The Nevada
City channel evidently headed a few miles east-northeast of that city in
the Harmony ridge, and is exposed in the East Harmony and Wesl
Harmony drift mines ;f it runs westward with a steep grade, and, curving
southward, emerges east of the Sugarloaf, in the old Manzanita diggings,
and thence passes on to the hydraulic mines northwest of the city
(American hill). From here on it is largely eroded away. .The large
amount of gravel in the lower part of this channel is remarkable. The
low divide toward the main river eastward formed a gateway through
which some of the rhyolitic tuffs poured down toward Nevada City.

Grades :

Manzanita — West Harmony, about 76 feet to the mile.

West Harmony — Harmony, about 190 feet to the mile.

The Grass Valley channel is somewhat different in having a compar-
atively small amount of gravel, it is covered with tuffs and volcanic
sands, above which, as usual, lies thecompact tuffaceous andesitic breccia.
It is separated from the Nevada City channel by a four-hundred feet
high bed-rock ridge, culminating in Banner hill. The first point where

♦ "Auriferous Gravels," p. ;;s0.

•(-These mines have been developed since Mr Pettee's visit to the place.

270 w. i.im><;i;kn — two neocene riveks of California.

it is met with is at the " Buena Vista slide/"* a few miles east of Grass
Valley : it is here covered by heavy masses of rhyolitic sand and tuffs—
an overflow from the main South Yuba channel ; from here it passed by
Krcs and Union hill across the eroded gap of Grass Valley, and thence
on through the volcanic ridge down to Rough and Ready. The possi-
bility is not excluded that this Grass Valley channel belongs to a some-
what later period than that of Nevada City.

( trades :

The average grade from the Manzanita diggings to supposed junction
with the main Yuba near Mooney Hat, 16 miles, is 115 feet to the mile.

The same from Buena Vista to the same junction, 16 miles, is about
1 22 feet to the mile.

The actual grade of the Grass Valley channel from Buena Vista slide
to Rough and Ready is about 72 feet per mile. This necessitates a heavy
fall for the lower part of the Neocene Deer creek.

French Corral la North San Juan. — Between these two points the
channel is nearly continuous, and the volcanic beds once covering the
gravel arc almost completely eroded. This part of the channel has been
described in detail in "Auriferous gravels," page 190 et se<p and page
.'is.") et seq., and also previously to this by Mr J. D. Hague. f Attention
should he called to section B B, which excellently illustrates the topog-
raphy of the ancient valley. It is seen that, without allowing anything
for subsequent erosion, the northwestern side of the valley rose 1,300
feet in a short distance; it culminated in the (not shown) Oregon peak,
a high diabase ridge 1,700 feet above the channel.

Grade :

From French Corral to North San Juan the grade is pretty regular
and averages, in 7 miles, 05 feet per mile.

North San Juan to Badger Hill. — In seeking to trace the Neocene rivet-
further up the slope from North San Juan there are only two places
which can he connected with it. The one which doubtless indicates the
continuation of the main channel upward is Badger hill. The stream,
of which we find the outlet at Badger hill, must in fact have connected
with San Juan ; high bed-rock bars any other way. This lias been
universally recognized by all investigators of the region.

Grade :

North San Juan to Badger hill, 4] miles, 80 feet per mile.

#

*The elevation of the bed-rock at this place is somewhat doubtful mi account of sliding masses
of claj and sand ; it is probably not far from 2,750 feet.

fThe Water and Gravel Mining Properties belonging to the Eureka Luke and Yuba Canal Com-
pany, 1876.

DISPLACEMENT OF GRAVEL BEDS. 271

THE NORTH FORK.

Another series of auriferous gravel deposits which can be connected
with North San Juan begins at Camptonville. That this is extremely-
probable has been sufficiently pointed out by Mr Pettee.* I may add
that here, too, high bed-rock on either side of Oregon creek prohibits
any other outlet excepting that cut by the modern canyon.

From Camptonville this Neocene stream, which corresponds to the
present North fork, continued to Depot hill by way of Galena hill and
Weeds point (p. 428), and then undoubtedly connected with Indian
hill, on the brink of the North Yuba canyon. Near this point it prob-
ably forked again, the more important stream crossing the present North
fork to Brandy City and Council hill and continuing up toward La
Porte and Gibsonville. This branch of the old river will not be followed
any further northward in this paper. Toward its sources, near the center
of volcanic activity in Sierra and Plumas counties, evidences of disturb-
ances of the gravel beds by faulting became very frequent.

At Depot hill the Neocene stream flowed through a canyon, the walls
of which rose about eight hundred feet on the western side and one
thousand feet on the eastern side, with a slope often or eleven degrees.

Grades :

North San Juan to Camptonville, 91 feet per mile (from a supposed
point of junction one and a half miles above North San Juan).
Camptonville to Depot hill, 3£ miles, 135 feet per mile.
Depot hill to Indian hill, 1 mile, 100 feet per mile.
Depot hill to Brandy City, 3 miles, 126 feet per mile.

THE MIDDLE FORK.

Badger Hill to North Bloomfield. — It has never been seriously ques-
tioned that there is a continuous channel between these points ; its
lower course is approximately outlined by the gravel area extending
between Lake City and Badger hill by way of North Columbia and
Cherokee. The gravel beds here attain the enormous thickness of five
hundred feet, and up toward Lake City become covered by thick de-
posits of clays and volcanic (lows.

Grade :
For reasons stated later on it is not probable that there is an even
grade between North Bloomfield and Badger hill. It is altogether more
probable that for the first four and a ball' miles from Badger bill the
^rade is very gentle, about 14 feet per mile, and that the sleeper grade
of the North Bloomfield channel begins at a point somewhat east of

* Auriferous Gravels, p. 428.

272 W. LINDGREN — TWO NEOCENE RIVERS OF CALIFORNIA.

North Columbia ; this grade would be approximately 158 feel per mile
in a distrance of 3 miles, an extraordinary contrast indeed. Mr Pettee*

assumes an even grade of 72 feet per niile.f

North Bloomfield to Snow Paint. — There has been a belief prevalent for
a long time that the Bloomfield channel connects eastward with the
Woolsey flat, Moores flat, and Snow Point areas. The line of connec-
tion is given by Mr PetteeJ as being via the Derbec and Watts shaft-,
and necessitates the very improbable grade of 290 feet per mile between
North Bloomfield and the latter place, while the grade between Watts
shaft and Woolsey flat would only lie 60 feet per mile. Mr Pettee
thinks faults or rapids might possibly occur some distance east of North
Bloomfield.

As to the Derhec shaft, it certainly is not on the main channel ; neither
is it very well possible that the Watts shaft is, for there is an inlet north
-of Backbone house which is considerably lower than the lowest point
in the Watts channel ( 3,800 feet). At this point there is a steep lava
bluff underlain by heavy masses of clay; enormous slides have taken
place, obscuring the relations of the strata, and the lowest bed-rock point is
not easily ascertained with precision. My elevation for this point
was made with an aneroid from the known elevation of Backbone
house directly above; the lowest bed-rock point would be about 700 feel
below the Backbone house, and the elevation 3,400 feet, with a probable
error of 50 feet. This is just above the point where Bloody Run makes
a sharp turn to the east; on both sides of the creek north of this inlet
there are benches of gravel at least as low down as 3,500 feet, indicating
plainly, with their bed-rock rising eastward and westward, that a new
eroded channel once occupied the space between them. Prom here the
Bloomfield channel must have curved eastward and followed the pres-
ent canyon up to near Woolsey flat, where it again made a bend south-
ward. The gravel exposed on the opposite side of the Middle fork of
the Yuba on the ridge between Kanaka creek and the river at an eleva-
tion of 4,0,00 feet, with rising bed-rock northward, lends additional
strength to this view. Watts shaft in all probability only represents a
tributary to the main river.

From Woolsey flat the continuation of the channel is very distinctly
indicated by Moores Hat, Orleans and Snow Point, as pointed out by
Mi- Pettee;§ at Orleans and Snow Point the stream flowed in a com-
paratively steep, narrow valley. The bed-rock immediately to the south

♦ Auriferous Gravels, i>. 392.

t Mr Pettee's distances vary somewhat from those here Adopted, which 1 have endeavored to
measure along the probable curves of the stream.
| Auriferous i rra\ els, p. 309 el seq.
I Auriferous Gravels, p. 203,

DEPOSITS OF TRIBUTARY CHANNELS. 273

of these points rises in a short distance 700 feet above the bottom of the
channel.

Grades :

North Bloomfield to Backbone inlet, 3 miles, 152 feet per mile.

Backbone inlet to Moores flat, 4J miles, 137 feet per mile.

Moores flat to Snow Point, 21 miles, 87 feet per mile.

The Derbec Channel — The Derbec shaft is sunk on a very different
channel from that of North Bloomfield; it pays for drifting, which the
main channel docs not, as a rule, and it carries a great many granite
bowlders, which I think are derived from a hidden area under the volcanic
flows rather than carried down from the granitic area above Washington.
It has been mined for a distanee of 3,500 feet in an easterly direction
from the shaft. It represents a tributary to the main channel, and I
think it very probable that it connects under the lava with the Belief
inlet, its course from there upward is very uncertain, as so much of it
has been eroded. A connection with the Omega gravel area and others
below that on the brink of the South Yuba canyon seems quite probable,
but the problem is complicated by the existence of the deep Centennial
channel on the Washington ridge, and more investigations are necessary
before a final result can be reached. On the other hand, the Derbec
channel undoubtedly joins the main channel at some place between
North Bloomfield and the Backbone house.

Grades :

Derbec shaft to Relief, 3 miles, 115 feet per mile*

From the Derbec shaft down to the main channel there is a pretty
heavy grade of about 120 or 150 feet to be accounted for, hut the dis-
tance, allowing for some curves, might have been nearly one mile.

The Forest City ('limine!. — The channel between Orleans flat and Forest
City is sufficiently known from Mr Pettee's notes. f Above Forest City
the Neocene valley is continuous as far as City of Six, overlooking
Downieville. From here it is not easy to trace it any further.

Between Forest City and the Ruby mine there is, however, a break in
form of a mass or dike of volcanic rock. At the Ruby nunc there are
two channels, one lower connecting with the City of Six, and one upper
running toward Forest City. The Bald Mountain Extension is mining
a tributary from the northeast. In its former tunnel a basalt dike was
found cutting across the andesitic breccia and showing that the eruption
of the basalt masses of the Forest hill table mountain took place in tin
vicinity.

* Auriferous Gravels, p. 105.
t [bid., p. 4;;:! e< seq.

XLI— Buix. Of.oi.. Soc. Am., Vol. 4, 1892.

s

274 W. LINDGREN — TWO NEOCENE RIVERS OF CALIFORNIA.

Grade :

From Orleans flat to Forest City, 51 miles, 70 feet per mile.

Snow Point to Milton. — Mr Pettee regarded it as improbable that any
stream ever came down to Snow Point from an easterly or northeasterly
direction,* and evidently considered the Forest City channel as the main
Neocene Middle Yuba. He states, regarding the country to the north-
east of Snow Point,t that " it is thought b}r some that a channel will be
traced from Haskell peak by way of Chips hill v. near Sierra City) to a
junction with another channel coming from a more easterly direction,
and that the two united follow a course under the lava by way of Amer-
ican hill and Nebraska to some point near Forest City. . . . Others
think that the high channel followed an independent course toward the
south anil crossed the line of the present Yuba river near Milton with-
out making any connection at all with the lower channel, which passes
by Forest City." Mr C. W. Hendel, who is intimately acquainted with
the mining industries of Sierra and Plumas counties, appears to have
been the first to announce the former view as long ago as 1872, J but he
carries his channel down from Plumas county by Beckwith pass and Cold
lake somewhat regardless of grades and intervening bed-rock ranges.

Mr Pettee states that his examination was hardly sufficiently extended
to warrant the expression of any decided opinion, hut that, while he was
not ready to assert that there were no old gravel channels, he did not
think it proved that any existed in this vicinity. ^

The careful examination of the country between American hill and
Milton cannot fail to convince any one of the existence of a decided
trough or depression below the lava, so deep as to justify the conclusion
that it represents the principal Middle Yuba during Neocene times.

The outlet of this channel is undoubtedly found at or near American
hill, on the southern bank of Wolf creek, while Nebraska and the gravels
between the forks of Wolf creek represent tributaries to the main river.
The gravel banks exposed at Bunker hill (near American hill) are
about three hundred feet high, and the dee}) trough-like channel is
clearly indicated. From the outlet at American lull there is hardly any
other course possible, down stream, than across the eroded canyon of
the Middle Yuba toward Snow Point. That a large channel ever passed
across the Craniteville gap at Shand's hotel is, for a great number of
reasons, not at all likely. The elevation of this gap is 4,625 feet.

For at least ten miles above American hill the channel is hidden under
the lava flow on tin- north side of the Middle Yuha. On the north-

* Auriferous Gravels, i>. 401.
flbid., p. 442.
I [bid., p. 210.

J Ibid., p. 44li.

CHANNEL OF THE ANCIENT MIDDLE YUBA. 275

western side the bed-rock is very high, sometimes forming the crest of the
divide between the North and Middle Yuba. On the other hand, the
lava bed-rock contact runs very low on the slope of the canyon side, while
it rises to considerable elevations on the opposite, southeastern side of
the river. This relation is clearly illustrated in section D D (plate 7). For
a long distance above American hill there is no indication that the chan-
nel passes out from under the lava into the eroded canyon. Supposing
a fairly uniform grade from Milton to American lull, it cannot emerge
until about nine miles from Milton, and very possibly less. At any rate,
the old channel for many miles above American hill would appear to
offer an excellent field for drifting operations. It is easily accessible
from the canyon of the Middle Yuba by moderately long tunnels, which,
for instance, at the section D D would probably have to lie placed at an
elevation of 5,000 feet. It is quite likely that the gravel in this channel
would pay for drifting, especially as it would have received the debris
from a part of the quartz mines south and southwest of Sierra City. An
attempt to open up this channel was made at the Savage tunnel, about
four miles above American hill, but it was abandoned long before com-
pletion.

Attention should he called to the deep valley through which the section
shows the channel to have flowed. Those accustomed to profiles of equal
horizontal and vertical scale will readily recognize the abrupt slopes of
its sides. It is not probable that Pinoli peak lias suffered any large
degradation since the Neocene times, as andesitic Hows cover it on the
eastern side almost to the top.

High bed-rock continues on the divide north of the Middle Yuba up to
Milton, while the lava runs far down on the northern canyon slope. The
detailed investigations in this region have not yet been completed, and
just where the channel leaves the lava How and follows the eroded course
of the present river is not quite certain. Neither to the north nor to the
south is there, however, as far as I am aware, any possible outlet by
which it could have turned from this course until Milton is reached.

At Milton, however, there are both north and south of the Middle
Yuba places with sufficiently low bed-rock to allow the Neocene river to
deviate from its course parallel to the river. The first is about a mile
southeast of Milton and forms the distinct outlet of the subsequently
described Milton-Meadow lake channel; its elevation is not far from
5,950 feet. The second is northeast of Milton, where a gap appears to
exist, with rapidly rising bed-rock on both sides. The approximate ele-
vation of this gap, which I do not know from personal inspection, has
been determined by Mr Pettee to be 5,938 feet.- It would seem to rep-

* Auriferous Gravels, p. 112.

276 W. LIMA, REX — TWO NEOCENE RIVERS OF CALIFORNIA.

resent a tributary coming down from the vicinity of Haskell peak. The
high bed-rock ridges mar Haskell peak, the northern side of which have
been examined by Mr H. W. Turner, preclude, except by assuming very

large subsequent disturbances, any supposition that a channel could
have flowed northward from Milton.

Grades :

American hill to Snow Point. 4' miles, 114 feet per mile.

American hill to Milton, 11 miles, 107 feet per mile.

Milton to Meadow Lake. — -Between these two places, a distance of 11
miles, there exists a deep channel entirely covered by volcanic rocks. 1 1
is easily traceable by means of a lower flow of rhyolite and by means of
conspicuous bed-rock ridges rising on either side. The highest of these
is English mountain, through which the section E E is laid. It shows
that in some places, at least, the bed-rock peaks rise to a height of 2,000
feet above the ancient rivers* The outlet of this channel is, as mentioned
above, about one mile southeast of Milton, at the base of a high andesitic
bluff underlain by rhyolite; it does not seem as if this rhyolite flow had
extended much farther in a westerly direction from here. An attempt
has been made to open the channel in this place ; an old tunnel is still
visible, but I do not know how the enterprise succeeded. Some coarse
wash gold is said to have been found in this vicinity ; there is no evi-
dence of any considerable amount of gravel. So far up as this the old
rivers probably did not accumulate much more gravel than the present
streams do now in bars and stretches of slight grade. Whether the
channel would pay for drifting is a doubtful question.

The distinct inlet of this channel is found between Fordyce and
Meadow lakes at an elevation of nearly 6,700 feet. It is clearly indi-
cated by the trough-shaped depression filled with rhyolite ("white
lava ") between the high granitic hills west of Meadow lake and the slate
ridges of the main divide about two miles to the northeast. It would
seem almost certain that this part of the ancient stream — east of Meadow
fike — would be auriferous ; the detritus from the Meadow lake quartz
mines must have been swept down into this trough. Whether aurifer-
ous enough for drifting is another question. No gravel is visible at this
point; moraines cover, however, a great deal of the ground here and
obscure somewhat the relations between lava and bed-rock.

The course of the stream above this point is not known ; its uppermost
course has been swept away by the erosion of the North creek. High
granite ridges rise southward and eastward ; in fact we are now near tic
source of the Neocene river; the Neocene divide is only live or six miles

\ shoulder projecting from English m tain, which lias 1 n somewhat exaggerated in the

drawing, produces the impression ofa terrace. Such a terrace or bench does nol exist in reality.

EXCEPTIONALLY HEAVY GKAVEL DEPOSITS. 277

distant and its lowest passes eastward were at least one thousand feet
higher than the stream at Meadow lake.

Grade :
Meadow lake to Milton, 11 miles, 73 feet per mile.

THE SOUTH FORK.

Badger I fill to Dutch Flat— From Badger hill to Dutch Flat or Gold
Run extends, about parallel to the axis of the Sierra, a series of extraor-
dinarily heavy gravel deposits, largely denuded of their volcanic cap and
especially adapted for mining by the hydraulic process. It formed a
part of the old " blue lead," that mysterious stream which was formerly
believed to have flowed north and south along the Sierra with a supreme
disregard for grades and high slate ridges. The true relations of the
deep channelin these deposits have been extensively discussed, especially
in the "Auriferous gravels ; " but Mr Pettee, who carefully examined the
gravel mines along this line, was unable to form an opinion which could
reconcile the apparently conflicting facts of grades and directions.

Mr Pettee stated* his belief that no deep channel will ever be found be-
tween Badger hill and Grizzly hill, but afterward suggested f that a con-
nection existed between Blue Tent and Badger hill by way of Grizzly hill :

" It seems most probable that this portion of the gravel field represents a broad
estuary or lake-like expansion of water at the junction of two streams or where
two streams by the filling up of their channels and the covering of the low inter-
vening ridges became practically one. If this latter view is correct, it is not im-
possible that there may once have been a current from Grizzly hill toward Colum-
bia hill even if the slope of the deep bed-rock is just in the opposite direction."

Mr Pettee^ ^ee^s confident that no deep channel exists between Blue
Tent and Scotts flat. He did not. however, examine the intervening
ground. The continuity of the deep flat channel between Quaker hill
and Dutch Flat is not denied, but he believes that there is also a deep
channel with slight grade between Dutch Flat and Indiana bill, which
would complicate matters greatly, for the channel at Indiana hill drains
directly toward the deep channel of the Neocene American river.

After stating the facts based upon his excellent barometrical measure-
ments, which 1 have extensively used in this paper, Mr Pettee says:

"It does not seem possible that there was ever a deep channel flowing in either
direction between Quaker hill and Indiana hill. Dutch Flat or Thompson hill
must have stood at a parting of the Mays, and it is very probable that there was
another such parting between You Bet and Red Dog."

* Auriferous Gravels, p. 393.

t [bid., p. 415.

J; Auriferous Gravels, p. 413.

278 W. LINDGREN — TWO NEOCENE RIVERS OF CALIFORNIA.

As a possibility, he mentions in another part of the volume* that the
Red Dog channel may have found an outlet along the present Green-
horn river in a southwesterly direction.

The first question to be disposed of is whether or not there is a con-
tinuous channel between Dutch Flat and Indiana hill with a southward
grade, as Mr Pettee thinks. It is admitted that there is a deep channel
coming down along the Dutch Flat diggings, and that the elevation of
this is 2,848 feet at Thompson hill. A short distance south of this.
Squires canyon crosses the gravel area connecting Dutch flat and Indiana
hill at an elevation of about o,050 feet, or 200 feet above the bed-rock in
the low channel of Thompson hill. Regarding the place Mr Pettee f says
that "Where the gravel range is crossed by Squires canyon the country
rock is seen on each side with a width of about 500 feet of gravel and
tailings in the bottom of the canyon. How much more slate was visible
before the accumulation of gravel began it is not easy to determine, but
it appears as if the slate did not extend entirely across " . . . The
result which I reached after two careful examinations was that the bed-
rock does extend entirely across the supposed gap, and this effectually
disposes of any deep channel connecting Dutch Flat and Indiana hill.
The slate proper does not begin until further down the canyon. The
bed-rock at the disputed place is the soft and decomposed gabbro of
Dutch Flat, which in places looks very much like clay. There are a great
many other considerations which favor the same result. The gravel areas
of both Plug Ugly and Jehoshaphat hills between Squires canyon and
Dutch Flat canyon have the distinct character of inclined benches above
the main channel, through which benches a supposed connection south-
ward could only have been effected by a deep and improbable gorge.
Dutch Flat and Indiana hill were evidently separated by a, low divide
corresponding to the present American-Yuba divide. When the deep
channel was filled up with gravel masses the stream began to deposit its
load on the adjoining broad inclined benches. Finally even the divide
was covered by the gravels, and a bifurcation might have taken place in
the latter part of the gravel period by means of which some of the waters
of the Yuba found their way over to the American watershed.

If the Tertiary deposits and flows were removed from the region
between Dutch Flat and Badger hill an old longitudinal valley would be
exposed to view with a high ridge rising both on the eastern and the
western side. It cuts the strike of the probably ( arboniferous clay slates
and siliceous slates at a small angle. The lateral ridges are in part com-
posed of harder siliceous rocks, in pail of softer clay slates. The only out-

'■■ Auriferous Gravels, p. it:'..
tAurii'erous Gravels, p. 153.

FLOWS OF VOLCANIC MUD. 279

lets along this line westward are the narrow canyons cut by the present
] Jear, Steep Hollow, G reenhorn and South Yuba rivers. Through none of
these canyons is there the remotest possibility that the ancient river passed
westward. High bed-rock is exposed in each case on both sides of
the gap cut by the recent rivers, and not even the smallest remains of
any Neocene deposits are met with for some distance below any of the
supposed gaps. Any such supposition would, moreover, necessitate ex-
tremely improbable and curious bifurcations. Along the whole line,
Dutch Flat to Badger hill, there are gravels accumulated to an excep-
tional depth and extent. Above these gravels rest, at many places, the
remnants of an eroded Mow of rhyolitic tuffs and sands. They are firs!
met with in Canyon creek, about five miles above Alta. They are ex-
posed at Shady run, at Alta, at You Bet, at Hunts hill, at Buckeye bill
and at Quaker hill. Again, they are exposed at Seotts Hat, on the north-
ern side of Deer creek, and, finally, at Blue Tent, where their volcanic
character begins to be less apparent, being largely mixed with other
detrital material; but everywhere they form a sheet perhaps a, hundred
feet thick and resting on several hundred feet of gravel.

The continuity and the direction of these Hows of rhyolitic mud are
distinctly and unmistakably indicated on the geologic map. Coming
down the old channel along the upper course of Canyon creek, they
flowed in a southwesterly direction, passing Alta, and Dutch Flat, down
to You Bet. Turning here with the valley, they flowed northward by
Quaker hill to Blue Tent. Between Blue Tent and Badger hill the vol-
canic masses are completely eroded and the underlying gravel beds
exposed.

Mr. Pettee traced the deep channel northward as far as Hunts hill, or
even, with a somewhat uncertain elevation, to Quaker hill. If he had
examined the relations at Seotts Hat and the country between Seotts
flat and Blue Tent, I am confident he would have arrived at the same
conclusion which has been reached here. At Seotts Hat there is the
most ample evidence that a very large channel crosses Deer creek, with
rapidly rising rim-rock on the east and west. The creek has not quite
<ait through the ancient river bed, the bed-rock being covered for a dis-
tance of nearly a quarter of a mile. The same accumulations of sands
and tuffs as are exposed at Quaker hill arc found abundantly above
Seotts Hat and in Rock creek between Seotts flat and Blue Tent. It
has been shown that the deep channel as far as Hunts hill has no pos-
sible westerly or southerly outlet. High bed-rock all along on the west-
ern as well as the eastern side from here northward simply makes any
other outlet than by Blue Tent impossible, if we do not assume entirely
improbable faults of several hundred feet of throw. There is no point

280 W. LINDGREN TWO NEOCENE RIVERS OF CALIFORNIA.

by which any outlet by way of Nevada City and Grass Valley could be
effected. The Harmony and Grass Valley channels are several hundred
feet above the Quaker hill channel. There were, however, two low gaps
in the ridge through which a part of the rhyolitic masses overflowed both
down the Grass Valley and the Harmony channels (-see page 269). From
Blue Tent, where the deep channel is only 500 feet above the bed of the
South Yuba, the direct continuation is given, as indicated by Mr Pettee, by
the correspondingly low trough of the Grizzly hill channel on the oppo-
site side of the river. Again, from here there is no possible low outlet
except by Badger hill, and this way the Neocene river must have taken.
Mr Pettee's own notes in regard to the former depth of the gravel :it
Spring creek confirm the existence of a deep channel beyond Grizzly
hill.* In channels of slight grade such as this one, ups and downs of
ten or twenty feet are very common. All these relations will appear
much clearer on the geologic map which, it is hoped, soon will be
printed.

If the deep channel between Blue Tent and Quaker hill would pay
for drifting it would be a magnificent field for enterprise. Unfortunately,
there are some doubts concerning this. The gold of extraordinarily
heavy gravel beds is more commonly divided through the whole mass
than concentrated on the bed-rock. However, drifting operations have
been carried on with profit at You Bet, and it is not improbable that
this part of the channel would pay well, at least in some places. It is
said that an attempt to drift the deep channel at the Blue Tent outlet
was not attended with success. The deposit would have to be opened
up by long tunnels from the' South Yuba canyon at Blue Tent, or east
of that place.

Section CO is atypical one through the great Neocene South Yuba
valley. On it may be noted the prominent bed-rock point of Banner
hill — composed of diabase-breccia — and the andesitic and rhyolitic flows,
as well as the upper gravel benches and the central trough or gutter. To
one peculiarity of the rhyolitic flows attention should be called : although
the flows descended the valley in a northwesterly direction and should
present a level surface from east to west, still it is found quite generally
that the eastern margin is higher by one or two hundred feet than the
western. It is perhaps best not to attach too much importance to tlii-^
as an indication of tilting, for in the first place a part of the flow was
drained off through one or two lower gaps toward the west, and in the
second place some erosion doubtless degraded the even surface in the in-
terval between the rhyolitic and the andesitic flows.

♦Auriferous Gravels, p. 393.

VARIABLE GRADES IN THE ANCIENT CHANNEL. 281

Tirades :

Wherever any parts of the deepest channel between Badger hill and
Little York are exposed a very slight grade is almost invariably found
to exist; it is so at Badger hill, Grizzly hill, Hunts hill, and You Bet.
This is a pretty distinct hint as to the general character of the channel.

From Badger hill to Grizzly hill, a distance of six miles, there is a
grade of sixteen feet to the mile. From Grizzly hill to Blue Tent across
the South Yuba there is practically no grade. From Blue Tent to Hunts
hill, a probable distance of eight miles, there is a grade of seventeen
feet to the mile. At Quaker hill the value found by Mr Pettee, but
which, according to him, is not quite reliable, was 2,650 feet, or 30 feet
higher than at Hunts hill. It must be remembered, however, that great
inequalities often exist in channels of gentle grade. In the Mayflower
channel, for instance, Mr Browne has shown the existence of irregulari-
ties of twenty feet above and below the general grade. At Scotts flat
the deep channel mentioned before has not been exposed. A shaft was
sunk long ago in the creek which did not strike bed-rock until two bun-
dred feet deep, at an elevation of 2,775 feet, but the channel below the
level of the creek is about 2,000. feet wide and the probability of strik-
ing the deepest depression by a single shaft without drifting is very
slight.

From Hunts hill to Red Dog the channel is practically level ; neither
is there any appreciable difference in level betweet Red Dog and Niece
and West's mine at You Bet, a distance of about three miles, in which
the deepest channel is hidden under heavy masses of gravel* Between
these last-named places several drift mines have been opened up, and in
them, as shown by Mr. Pettee,f the deepest bed-rock is somewhat higher
than at either end of the channel.

From the places there referred to as Heidliff 's and Mallory's claims
the bed-rock slopes down to Niece and Wests about 20 feet. Opposite
Niece and West's mine is an isolated fragment of the deepest channel,
known as " Waloupa," which place is again 30 feet lower than the bed-
rock at Niece and West's. This makes a total length of about one mile
in which the channel flowed in a nearly northeasterly direction. It is
certainly interesting and worthy of notice that in this rare instance of a
northeasterly direction the present grade of the Neocene channel should
liave the considerable slope of 50 feet to the mile in the opposite direction
to that of the river in general, so that if the present grade were also that
of the Neocene river it must at this point have flowed uphill for a dis-

* Mr E. C. Uren, of Auburn; has made a spirit-level survey along the surface between tie- (wo
points and informs me that both have th.e same elevation,
t Auriferous Gravels, p. 16C.

XLII— Bull. Geol. 8oc. Am., Vol. 4, 1892.

282 W. LINDGREN — TWO NEOCENE RIVERS OF CALIFORNIA.

lance of one mile. The character of the gravel at this place is not differ-
ent from that of adjoining parts of the old river. It must be admitted
that this instance strongly suggests a deformation of the Neocene river
lied by an increase of the westerly slope of the Sierra.

From Waloupa to Little York, a distance of one and a half miles, the
channel has a grade of 76 feet per mile. The direction has now turned
westerly.

From Little York to Dutch Flat, a distance of two and a quarter miles,
there is a grade of 63 feet per mile.

It should be stated that there is no perceptible difference in the char-
acter of the bed-rock between the Quaker hill and You Bet part of the
channel and the channel between Waloupa and Dutch Flat. The sud-
den increase in slope must be traced to other causes.

The Channel <t( Dutch Flat. — In the Dutch Flatchannel a considerable
rise of the bed-rock occurs and the width narrows. Large bowlders are
found on the bed-rock and everything indicates a rapid current. This is
partly explained by the belt of hard quart/.ite and gabbro across which
the Neocene stream flowed at this place.

Grade :

In one mile, 227 feet.

The Liberty Jfill Tributary. — This stream, which must have joined the
main channel at the upper end of the Dutch Flat diggings, can be easily
traced by way of Elmore hill. Liberty hill, Lowell hill and across Steep
HoIIoav creek to Remington hill. From .here its course has not certainly
been determined.

Through the recent operations of a Gold Hill, Nevada, company at the
Centennial tunnel and shaft the existence of a deep channel from Phelps
hill southward lias been proved. According to information obtained
from the superintendent, Mr H. Richards, this channel, where at present
met with in the tunnel, is wide and flat, and has a grade eastward of 75
feet to the mile. The channel exposed by the San .lose shaft is stated to be
60 or 70 feet higher than the first channel, and probably connects with it
at some point further southward. There is, on account of high bed-rock,
no possibility that- the Centennial channel connects under the ridge with
the Omega channel, and the probability seems to be that a continuous
channel exists between Phelps hill and Remington hill, with a general
north-and-south direction. If so, its grade must, on the whole, he
slight, for Phelps hill is only 200 feet higher than Remington hill, which,
with a distance of four or five miles, would give an average grade of 40
or 50 feet to the mile. The Centennial channel contains granite bowlders,
which would seem t<> indicate that its headwaters were up in the granite

LITTLE KNOWN ANCIENT TRIBUTARIES. 283

area above Washington. If this be the case, on the other hand, the
Relief channel could not very well have connected with the Omega.
Many complicated questions remain to be worked out in this vicinity.

In this connection mention might be made of the curious relations
near mount Oro, a few miles east of Quaker hill. The same volcanic
area that overlies the Phelps Hill-Remington channel covers this vicinity.
but under it at mount Oro there appears to exist, if my information is
correct, a depression which, as exposed by old inclines, is much deeper
than the rims of the lava flow are at any place; it is at a lower elevation
than both Phelps hill and Remington hill, and no possible outlet can be
suggested.

Whatever the relations of the Centennial channel will ultimately prove
to be, I think it probable that a fork of the principal channel continued
from Remington, by way of Democrat and Excelsior, in a northeasterly
direction under the volcanic cover for some distance up toward Omega.

Grades :

Upper Dutch Flat to Liberty hill, 11 miles, 183 feet to the mile.

Liberty hill to Lowell hill, 31 miles, 136 feet to the mile.

Lowell hill to Remington hill, \ mile, 90 feet to the mile.

The Channel between Alta end Shady Ran. — Cut off for some distance by
Little Bear creek, the principal channel is found again emerging from
under the volcanic cap at Nary Red, northwest of Alta. Some parts of
this channel near Nary Red have been drifted. Near Alta two shafts
have been sunk on it, In the one to the north of the railroad, according
to information received of Mr E. C. Uren, of Auburn, bed-rock was
reached at 200 feet and good gravel found, not rich enough, however, to
pay for mining by shafts. At this point the main channel appears to
have been joined by a tributary coming in from the west at the Moody
gap. on the divide between Canyon creek and the American river and
crossing Canyon creek south of Alta. The main channel continues, I
have no doubt, under the lava cap up toward Blue Bluffs at Shady run,
where it probably forked again, one fork, the deposits of which now are
mostly eroded, continuing up toward the Neocene highlands near risen,
by way of the isolated gravel area of Lost Camp, the other fork continu-
ing for some distance up toward Blue canyon and Emigrant Gap under
the lava ridge.

It would seem as if ihe deep channel from Alta up toward Blue canyon
would offer a- good field for mining enterprises.* The upper part of it
is accessible by tunnels from the steep side of the canyon of the American

♦Attention u as some time ag". ami very justly, drawn to the existence of this channel by Mr James
F. Talbott, of Shady run, in a series of articles in the Mining and Scientific Press of June 14, L890
et seq., vol. 60, No. :U, et seq.

284 W. LINDGREN — TWO NEOCENE RIVERS OF CALIFORNIA.

river and the lower part by tunnels from Nary Red, or from certain parts
of Canyon creek. It is doubtful whether this channel extends up to
Emigrant Gap. The relations of the bed-rock to tbe lava at this place
lead me to believe that it is ratherthe Omega channel, which extends up
by Bear Valley house, near Emigrant Gap, and from there connects with
the short distance of channel clearly indicated some distance south of
( lisco. Tbe steepness of the sides of this channel, which is remarkable, is
illustrated in section F F. In a distance of three miles it has a grade of
four hundred feet, or 133 feet to the mile. The channels above Emigrant
(Jap do not. I think, carry gold enough to make their exploitation
profitable.

Grades :
Dutch Flat to Nary Red, one mile, about 225 feet.
Nary Red to Blue Bluffs, four miles, about 125 feet to tbe mile. Tbe
bed-rock at Blue Bluffs slopes in toward the ridge.

The Neocene American River.

Ridges of older rocks separated the watershed of tbe Neocene American
river from that of the Yuba. The North fork of the American drained
the region of Forest bill, and its sources are found near Summit valley,
at the crest of the range. The South fork drained the Placerville region,
and it appears to have headed among the peaks south of lake Tahoe.
Only part of the latter drainage system has been mapped.

THE SOUTH FORK.

From the Sacramento Valley to Diamond Springs. — The accumulations
along the lower part of tbe Neocene American river are to a very great ex-
tent destroyed by subsequent erosion, and to reconstruct that part of tbe
river is consequently not very easy; moreover, it has only a theoretical
interest, since nearly all of the auriferous gravels along it are swept away.
In discussing tbe direction of the river from near Diamond Springs, the
lowest point to which he traced it down to the plains, \\\ A. Goodyear
expresses the opinion that it probably passed through the gap al Pilot
Hill and thence to Folsom, where large accumulations of gravel occur*

Any other course than by Pilot Hill is indeed out of the question on
account of high bed-rock ridges. That it followed the windings of the
canyon of the South fork where it cuts through these ridges is so improb-
able a proposition that it may be left out of the discussion. No remnants
of gravels or volcanic flows, however insignificant, are found along this
course to give probability to such a view. That the river continued from

* Aurilerous GravelSj p. 004.

ANCIENT CHANNELS FILLED BY PLEISTOCENE DEPOSITS. 285

Diamond Springs in a northwesterly direction toward Pilot Hill is indeed
proved by the small remaining deposit of gravel and rhyolitic tuff found
at the low, broad gap of Granite hill in such a position that it must in-
dicate the lowest point of the channel at this place. The town of Pilot
Hill occupies a similar position in a broad gap, on each side of which
hills of older rocks rise to a height of several hundred feet. Besides
some Pleistocene angular gravel, there is found at this place a small rem-
n; nt of another deposit with large, very well rounded bowlders, such as
can lie formed only by a stream of some magnitude. The course from
here on is largely hypothetical, but it may be assumed as probable that
the river continued in a westerly direction for some miles, joining the
Neocene North fork coming down from the vicinity of Forest hill. From
here on the two rivers, united, probably flowed in a southwesterly direc-
tion to the Neocene gravel masses exposed and mined near the plains
between Rocklin and Folsom, at the Lee or Chabot drift mine. From
this point the ancient river is hidden under the later accumulations of the
plains. The Neocene surface in this vicinity appears to have formed a
gently undulating country with little relief as compared with the lowest
part of the Yuba river. This is explained by the occurrence of a large
massif of easily eroded and crumbling granitic rock, over which the old
river here made its way. That the gravels at the Lee mine are pre-vol-
canic cannot be absolutely asserted, but they are certainly of Neocene
age.

If the gravel at the Lee mine represents the lowest point known of the
Neocene river, it follows that it was here only about 100 feet higher in
elevation than the present river in a corresponding position is now.

On the northern side of the sloping breccia table of " Bowlder ridge,"
extending from Auburn to Lincoln, there is another Neocene depression,
the gravels of which have been drifted in places; but this cannot repre-
sent the lower course of the Neocene American, for a low granitic ridge
separates it from the basin in which the continuation of the upper courses
of this stream must be sought. On the other hand, the large accumu-
lations of gravel near Folsom are distinctly post-volcanic and were ac-
cumulated by the river in early Pleistocene time. That the Neocene
river followed the course of the present stream from Folsom up appears
very improbable and is not supported by any geologic evidence.

( ! rades :

Lee mine to Pilot Hill, about 12 miles, 80 feet to the mile.
Pilot Hill to Granite hill, 11 miles, 32 feet to the mile.
Granite hill to Diamond Springs, 0 miles, 21 feet to the mile.
Diamond Springs to Newtown. — After a detailed examination of the
gravel region in the vicinity of Placerville, Goodyear arrived at the con-

286 W. LINDGREN — TWO NEOCENE RIVERS OK CALIFORNIA.

elusion that a stream of considerable magnitude once approximately

followed the course of the present Webber creek from Diamond Springs
to Newtown, and into which the complicated channels of the vicinity of
Placerville emptied* His observations did not extend beyond New-
town.

Alter a careful examination of the region I can only confirm his con-
clusion, with the addition that this stream without doubt represented
the ancient South fork of the American river. It is very distinctly the
deepest depression between the highlands of the Georgetown divide on
the north and the high ridges on the south separating the Neocene
American from the Neocene Cosumnes. The vicinity of Placerville, like
the Forest hill divide, is characterized as a broad and flat Neocene de-
pression, in which intervolcanic streams have cut a complicated series
of channels. It should be noted that the oldest gravels of Placerville, as
a rule, are not deep, and that in most of them occasional rhyolite bowl-
ders are found. This would seem to indicate that during the earliest
part of the gravel period the conditions were not as favorable here for
the accumulation of river deposits as further northward.

About a mile west of Newtown the channel makes a curve, entering
the volcanic ridge to the south of Webber creek. It then again turns
northward, crossing the south fork of Webber creek about three-quarters
of a mile to the northwest ot Newtown.

Grades :

Diamond Springs to Webber hill, 2 miles, 71 feet to the mile.

Webber hill to Newtown. 7 miles, 69 feet to the mile.

Newtoicn to Pacific House. — After crossing the South fork of Webber
creek the deep channel disappears under the volcanic capping of the
ridge between the two forks of Webber creek, at a place formerly called
Iowa City, but now generally known as Snows ranch. From this point
it must continue under the eruptive rocks up to the Pacific house, on
the stage road between Placerville and Lake Tahoe, where it crosses the
present South fork of the American. The existence of a deep trough is
unmistakably indicated by rising bed-rock toward the north and the
south, by the pitch of the bed-rock wherever exposed along the margin
of the volcanic area, and finally by the heavy flows of rhyolite and
rhyolitic tuff with which the old depression, up to a certain level, was
filled. A typical cross-section of this channel is shown in K K, with
the probable position and depth of the channel indicated ; it is, I believe,
sufficiently clear to explain itself. Some extensive mining operations
have been and are still carried on to find a deposit under the deep lava-

* Auriferous Gravels, p. 502.

UPPER COURSE OF THE ANCIENT RIVER. 287

How north of the North fork of Webber creek, but that any large and
important channel will ever be found on that .side is very unlikely.
except possibly at one point somewhat north of the section where a
tributary from the north appears to join the principal river by way of
Badger hill and Mooneys diggings (not indicated on the map).

The lower part at least of this large and important channel may not
unlikely be found to pay for drifting; it can only be opened up by
means of tunnels from near Snows ranch or from some places along the
North fork of Webber creek. Inclines along the rim will probably suffer
from a heavy influx of water.

At Pacific house the indications of an inlet are distinct, but I do not
think that much gold was ever found in the adjoining gulches. Oppo-
site that place, on a bench overlooking the South fork of the American
river, a small isolated area of gravel has been washed away by the
hydraulic process, and it is quite certain that the old channel crossed
the river at this point. More indications of the same channel are found
on the north side, a few miles eastward. Its course has not been traced
further, but it appears probable that it will be found to cross the river
again higher up, and that it headed up toward the Neocene volcanoes on
the line between Eldorado and Alpine counties. The channel is not
likely to be auriferous above the Pacific house.

A broad belt of Neocene highlands with lofty peaks and ridges occu-
pied the space between the upper courses of the North and South forks
of the American river, and on the Georgetown divide a spur extended
from these highlands far toward the west.

Grade :
Newtown to Pacific house, 10 miles, 100 feet to the mile.

THE NORTH FORK.

From the Junction to .Tone* Hill, — The lower course of the North fork of
the American river is almost completely destroyed by erosion ; its proba-
ble course from the valley up to the junction has already been mentioned.
Between the Lee mine and the Forest Hill divide there is only one re-
maining fragment, which, moreover, probably does not represent the
very deepest part of the channel, namely, the small patch of mixed
andesitic, rhyolitic, and metamorphic gravel found on top of the bluff at
the junction of the present North and Middle forks, about three miles
northwest of Auburn ; the presence of rhyolite in this gravel is a strong
proof that it came from the vicinity of Forest hill. This gravel is found
in the center of a very broad, low depression bordered on the north by
the Neocene highlands of ('Upper Gap and on the south by the rising

28S \V. LINDGREN — TWO NEOCENE RIVERS OF CALIFORNIA.

divide separating the watershed of the Neocene North fork from that of

the South fork. There are- several small volcanic areas, sometimes un-
derlain by gravel, two or three miles northwest of Auburn near the
railroad ; but these are too high to have formed part of the principal
channel. Between the small deposit mentioned and Jones hill no trace
of the ancient river can be found.

Grade- :

Lee mine to Auburn, about 14 miles, 86 feet to the mile.

Auburn to Jones hill, 9 miles. 63 feet to the mile.

Jones Hill to Bath. — A great many difficulties present themselves
when an attempt is made to reconstruct the drainage southwest of
Forest hill. Mr Browne has shown that a large antevolcanic channel
enters the Forest hill divide at Bath and, making a large curve, -passes
by the Mayflower mine; thence to near Forest hill, where it comes uear
the margin of the volcanic cap, hut turns again at the Dardanelles mine
and runs in under the lava in a northwesterly direction.

Another channel enters under the volcanic ridge at Yankee Jim.
Whether it connects with the Dardanelles channel is not known. The
volcanic ridge continues down to Peckham hill, but only later inter-
volcanic channels appear to exist below it. which would seem to indicate
that the older channel has in this vicinity been nearly entirely obliterated
by those of a later period, if. indeed, it ever followed this direction. 1
have provisionally marked the older channel as following the ridge down
to Peckhani hill and joining another channel near Yankee Jim.

The so-called Ponds channel near Todds valley is at too high an eleva-
tion to have ever formed a part of the lowest antevolcanic channel, ami
should, I think, rather lie considered as a bench gravel deposited after
the tilling up of the deepest depression.

The question of the continuation of the Mayflower and Dardanelles
channels is very much complicated by the existence of a detached series
of evidently antevolcanic gravel areas to the south of the Middle fork.
I have provisionally connected them with a line running from Jones
hill, with an elevation of 2.114 feet, by Floris, with an elevation of 2,530
feet, up to the channel which near Volcanoville emerges from the volcanic
ridge south of the Middle fork.* The deposit at Floris is 14i> feet
lower than the main Dardanelles channel in a corresponding position.
Any attempt to explain these apparent contradictions would lead too far
into the realm of hypotheses.

It is certain, however, that a channel of some magnitude came down
from the highlands of the Georgetown divide, crossed Otter creek at

- Feral small Neocene tributaries came down toward this line from the Georgetown divide.

VARIABLE GRADES OF THE OLD CHANNELS. 289

Kentucky flat, and continued from there under the lava cap to a place
a short distance to the northeast of Volcanoville; at one intermediate
point, Missouri gulch, it is exposed for a short distance.

Grades' :

Jones hill (2,114 feet) to Floris (2,530 feet), 5] miles, 76 feet to the
mile.

Floris to Volcanoville, 3 miles, 112 feet to the mile.

Volcanoville to Missouri gulch, 2 miles, 114 feet to the mile.

Missouri gulch to Kentucky flat, 2 miles, 62 feet to the mile.

Jones hill to Peckham hill, 1\ miles, 57 feet to the mile.

Peckham hill to Dardanelles, 5-i miles, 90 feet to the mile.

Dardanelles to Mayflower, 2\ miles, 52 feet to the mile.

Mayflower to Bath, 21 miles, 40 feet to the mile.

The Iowa Uill Channel. — Difficulties also exist in connectino; the Iowa
hill channel with the rest of the drainage. I have assumed that a con-
nection existed hetween Indiana hill and Iowa hill, and that the Iowa
Hill channel ran southward and connected with the inlet at Yankee
Jim. One of the principal objections to this view is the occurrence of a
small gravel body at an intermediate point, Kings hill, which appears to
he about 70 feet lower down than the lowest bed-rock at Yankee Jim. The
Iowa hill or Morningstar channel, as it is also called, has been described
in detail by Mr Hobson,* who concludes that the stream had a grade
toward the north, and that coming from some point on the Forest Hill
divide it was joined north of Iowa hill by a tributary from Indiana, hill,
after which it curved westward and flowed down toward the plains along
the canyon excavated by the present stream. Mr Hobson's own figures
on the maps and the profiles accompanying the paper do not seem to
me to warrant this conclusion, as far as the grade is concerned. The
bed-rock south of Iowa hill and at the hydraulic workings of the Morn-
ingstar has exactly the same elevation, according to the figures on Mr
Hobson's map, as the starting point at the southern end of the covered
channel at Wisconsin hill, a distance of between two and three miles.
North of Iowa hill there is a sudden descent of some 50 or 60 feet, but
the distance in which this descent is accomplished is only one-fifteenth
part of the whole length of the channel; and it looks very much as if
this depression were caused by a slight fault, especially as there are two
or three of such disturbances shown on his profile in the Morningstar
ground. An examination of Mr Hobson's profiles will inevitably lead
to the conclusion that before the faulting, whether this took place by air
uplift of the southern side or a downthrow of the northern, there was a

* Tenth Ann. Rep. State Mineralogist of California, p. 420.
XLIII— Bui.r,. Oeoi.. Soc. Am., Vol. 4 1892.

290 W. LINDGREN — TWO NEOCENE RIVERS OF CALIFORNIA.

slight southward slope from the Morningstar works to Wisconsin hill.
Mr Hobson's arguments, based on the occurrence of serpentine bowlders

in certain parts of the channel and on the relative elevation of the rhyo-
litic strata, are stronger. There are, however, such difficulties involved
in carrying the principal channel in the direction advocated by Mr
Hobson that I cannot adopt his view as the most probable.

Bath to Ralstons. — In discussing the upward continuation of the
large and deep channel at Bath, which is the same as that of the May-
flower mine. Goodyear indicated several reasons why it was probable
that it came down from the Long canyon country, the principal ones
being the occurrence in it of granite bowlders and its capping of" white
lava'1 (rhyolite). The vicinity of Long canyon was only examined in a
cursory way by < roodyear. There is. indeed, at the Ralston mine, in the
western part of the divide north of Long canyon, unmistakable evidence
of an outlet of a large and important channel; there is, further, a re-
markable and striking similarity between the accumulations of the Ral-
ston channel with those of the Bath-Mayflower stream : there is, further,
no other way open for the Ralston channel than in the direction of Bath,
for higher bed-rock bars the way both to the south and to the north ;
hence I feel justified in concluding that a connection once existed be-
tween the two channels, which has since been eroded by the recent
stream of the Middle fork.

Mr Browne is struck with the considerable extent to which the modern
rivers on the Forest hill divide have avoided the older channels, leaving
them buried under the volcanic flows on the top of the ridges.* To ex-
plain it he assumes that the ancient valley was tilled with volcanic ma-
terial only up to its widespread rims, but not to overflowing, and that
the modern rivers started by preference along the marginal lines of the
deposits. A study of the geologic map of the country north and
south of the Forest hill divide will show that there is no good reason
for such an assumption. On the contrary, the last flows almost com-
pletely flooded and buried the Neocene valley and its divides in this
vicinity : the only points rising above them were the high hills to the
west of the " Brimstone plains " and the Volcanoville hill to the south-
ward. Only on the upper part of the Georgetown divide were there any
continuous and important bed-rock ridges projecting above the general
level of the flows.

The explanation of Mr Browne might well he applied to certain parts
of the upper river courses, hut I do not think it explains the positions of
the present streams on the Forest hill divide. .Slight inequalities in the
surface of the andesitic flows probably determined first the directions.

♦ Tenth Ann. Rep. of State Mineralogist of California, p. 44-j.

TRIBUTARIES OF THE NORTH FORK. 291

Grade :

Bath to Ralston, 8 miles, 72 feet to the mile.

That Michigan Bluffs is not on the principal channel is also indicate.!
by the grades, for from that place to Bath, a distance of three miles, the
slope is 140 feet to the mile, while from Michigan Bluffs to Ralston, a
distance of five miles, it is only 31 feet to the mile.

The Damascus and Last Chance Tributaries: General Character. — Mi-
Browne has described the Damascus or " white " channel. Its course
above Damascus is eroded; it is practically continuous under the lava
cap as far down as Gas hill ; from there it is eroded for a long distance,
but the characteristic deposits are again found at Michigan Bluffs. It
is very different from the Bath channel, being all oust entirely composed
of quartz gravel, due to the fact of its flowing for a long distance over a
soft clay-slate with a large amount of quartz veins. A short distance
below Michigan Bluffs it must have joined the principal Middle fork.

Tributary to this channel was the Last Chance stream. Coming down
from the high country to the northeast of Last Chance, it is preserved
under the lava cap for some distance at Last Chance and again at Dead-
wood. It scciiis most probable that it joined the main stream some dis-
tance north of Michigan Bluffs. The relations of the lava and bed-rock
at the two first-named places clearly indicate that this channel flowed
in a very distinct depression or valley. Both at Last Chance and at
Deadwood there is an older ante-volcanic besides several cement or inter-
volcanic channels.

The important cement channel coming down from the vicinity of
Secret canyon by way of Hogsback and Red point under the lava flow
very likely followed an ante-volcanic valley; but of the deposits of the
latter but little is left.

Grades :

Damascus to Michigan Bluffs, SI miles, 73 feet to the mile.

Deadwood to Last Chance, 5 miles, 136 feet to the mile.

From the Ralston Mine to Summit Valley. — The divide between Long
canyon and the Middle fork of the American river is covered by very
deep Neocene deposits and volcanic flows. High bed-rock exists to the
north and to the south, forming the sides of a broad and deep depres-
sion, the center of which lies buried below the volcanic mass. This
deep depression extends in a northeasterly direction up toward Summit
valley a distance of about thirty-five miles, in which the deepest channel
is only exposed at one point, at the place where the North fork of the
American river cuts through it. This is the longest lava-covered stretch
of channel in the territory here described. The parallelism with the

202 \Y. LIXDGREX — TWO NEOCENE RIVERS OF CALIFORNIA.

present Middle fork should be noted, as well as the bend in its lower
course, which closely follows the curve of Long canyon.

The Lower ( iourse. - < >n the Long canyon divide — i. c., from the Ralston
mine to the place called Big Flume on the map — the deposits in the
channel preserve about the same characteristics. The general form of
valley and depth of deposits are illustrated in section ////(plate 7).

It appears as if the channel in the Long canyon divide had in mosl
places a broad, flat profile. On the bed-rock, as a rule, lies from twenty
to forty feet of non-volcanic gravel, composed of quartz. quartzite and
granite. Above this rests a series of alternating rhyolitic tuffs and
gravels with rhyolitic pebbles, which ranges in depth from L50feet at the
western end of the ridge to 400 or 500 feet up toward Big Flume. In
the western part of the divide the volcanic gravels are heavier, reaching
80 or 100 feet at the Ralston mine. Toward the east they grow thinner
and the rhyolitic tuffs begin to predominate. Above the rhyolitic tuffs
lie from 700 to 800 feet of andesitic breccia. The center of the channel
evidently lies on the southern side of the ridge toward Long canyon, and
an almost continuous fringe of gravels and tuffs are exposed along this
line. At Blacksmith fiat the bed-rock is propably not far above the
deepest depression in the center of the channel, which here reaches its
most southerly point. A smaller tributary at this place came in from
the south by way of Corcorans diggings and Clydesdale, the bed-rock at
the latter place, near the point between Long and Wallace canyons, being
a little higher than that of Blacksmith fiat. Again, at Russian ravine.
one mile south of Big Flume, the bed-rock is probably nearly as low as
that of the deepest channel.

Numerous attempts have been made on a small scale to mine these
gravels. At Ralstons the upper gravels have been hydraulicked with
satisfactory results ; many small diggings are found along the rim on the
southern side of the divide as far up as Big Flume, hut nowhere, so far as
1 am aware, has any systematic and extensive work been undertaken in
order to open up tins magnificent channel by means of tunnels. It
would seem very likely that some paying ground would he found along
it: some risk must he taken, for it is of course impossible to predict
whether a certain gravel channel will pay for drifting or not without a
trial. That the channel exists and that it is of great dimensions is quite
certain, hong canyon is said to have been rich in early days as far up
as Russian ravine, while the Middle fork contained less gold.

( rrades :
Ralston mine to Blacksmith fiat (assuming thai the bed-rock at the
latter place is hut little higher than in the deepest channel), 5 miles. 65
feet to the mile.

HIGH GRADES OF THE TRIBUTARIES. 293

Blacksmith flat to Russian ravine (on similar assumptions), 7 miles,
93 feet to the mile.

The Duncan Peak Tributary. — A short distance from Big Flume, on the
northern side of the ridge, there is a deep trough exposed, and known as
Marshall's claim. It is, according to my measurements, 50 feet higher
than the bed-rock in Russian ravine on the southern side, and it is filled
to a depth of about 100 feet with gravel, of which a little has been
hydraulicked. This place is evidently near the confluence of a tributary
(•(lining down with steep grade from the vicinity of the old Neocene
mountain of Duncan peak. From Flat ravine, on the south side of
Duncan peak, it runs down almost as a steep ravine to near the Gray
Eagle tunnel ; from here it must have connected across Duncan canyon
with the main channel of the American river by way of Marshal Is inlet.
Abrams tunnel on Duncan canyon is probably in the same channel.

Grades :

Flat ravine to Gray Eagle tunnel, 2 miles, 350 feet to the mile.

Gray Eagle tunnel to Marshalls inlet, 6 miles, 200 feet to the mile.

The Canada Hill Tributary. — On the northern side of Duncan peak
there exists another equally steep channel with thin angular gravel.
Starting from Canada hill it runs down in a northeasterly direction to
Sterrett's claim in Sailor canyon. From there its course is not deter-
mined beyond doubt, but it most probably curved around southeast-
ward and joined the main channel near French meadows.

Grade :

Canada hill to Sterrett's claim, in 3 miles, 1,000 feet, or about 333 feet
to the mile.

The upper Course. — From Big Flume the channel makes a curve toward
the east and crosses the present Middle fork at French meadows, near
Ralston dam. At this point the modern river is higher than the bottom
of the old channel, but the distance along which there is no bed-rock
exposed is short and there is no reason to believe that the deepest part
of the channel is very far below the present river-bed* Very little
gravel is exposed from here up toward Summit valley; the rhyolitic
flows have also changed character, containing more massive rhyolite and
less of tuffs than before. They increase in depth, their thickness at
French meadows being 600 feet, and south of Summit valley a maximum
thickness of almost 1,000 feet is reached.

Whether the channel from Big Flume up toward Summit valley will

* Mr J. H. Hammond, in the Ninth Annual Rep. State Min. of California, plate 2, gives a cross-
section from this vicinity where some prospecting has been done by tunnels ami inclines. He,
however, places the channel below the North fork, which certainly is incorrect.

294 W. LINDGREN — TWO NEOCENE RIVERS OF CALIFORNIA.

pay for drifting is a very doubtful question. It is accessible only by
Long and costly tunnels from the North fork side or by inclines from the
rims. There are but very few quartz mines along the upper course; the

channel here enters the generally barren granitic area of the high Sierra.

Near Soda Springs the deep canyon of the North fork has cut through
the channel, exposing on both sides the deep volcanic flows and the curve
of the old valley. Section L L is laid across the valley a little south of
this and shows sufficiently clearly the relations at this point. At Soda
Springs the recent river is about 200 feet below the Neocene channel.

We are now near the headwaters of the ancient river; on all sides rise
bed-rock ridges and peaks, prominent in Neocene as well as in the pres-
ent time. North of the North fork the old channel begins to rise rapidly
toward the summits. The valley opened up in a sort of amphitheater;
one branch extended up toward mount Lincoln, another toward Soda
Springs station. The principal valley extended up toward a point about
a mile west of Summit station, and its continuation can indeed be traced
a little further northward toward the high granitic counterforts of Castle
peak. The Neocene river, broad and magnificent on the Forest hill
divide, is here nothing more than a ravine.

Grades :
Russian ravine to French meadows, 6 miles, 100 feet to the mile.
French meadows to Soda Springs, 10 miles, 115 feet to the mile.
Soda Springs to Summit, '3 miles, 200 feet to the mile.

Discussion of Grades.

On plate 6 a first, and in many respects incomplete, attempt has been
made to show in a comprehensive manner the more important facts
about the present grade and directions of the ante-volcanic Neocene river
beds.

Before endeavoring to draw any conclusions from the present condi-
tion of these river beds it should be pointed out that the Sierra Nevada
is a very heterogeneous mass, composed of rocks of very diverse texture
and hardness, which are apt to influence the grade of the rivers flowing
over them. Sudden changes of grade are indeed not uncommon in the
present rivers as well as in the Neocene channels. It follows from this
that conclusions drawn from short distances of channel or based on
isolated occurrences cannot he reliable.

An influence of direction on grade probably also exists, inasmuch as
streams flowing parallel to the direction of the range would lie expected
to have a slighter grade than those breaking across the strike of the slates

HIGH GRADES OF OLD CHANNELS GENERALLY. 295

or cross-belts of hard massive rocks. Such an influence no doubt exists,
but it is certainly not very marked in the modern rivers. In the lower
Sierra, in which the direction of the rivers for shorter distances only are
parallel to the range, it cannot be stated to occur to any considerable ex-
tent; the principal forks have a fall of from 30 to 40 feet to the mile in
whatever direction they run. In the upper Sierra the Rubicon river
runs for fifteen miles near and parallel to the crest line, but the grade
averages very high — about 150 feet to the mile.

The grades of the intervolcanic channels must be left out of consid-
eration in endeavoring to ascertain whether the height of the range has
been increased since Neocene times, for it has been shown that their
erosive activity was similar to that of the present rivers, and that the
changes from the conditions of the earlier Neocene to those of today
took place or began to take place before the intervolcanic channel system
was established. Referring to Mr Browne's diagram of the grades of the
volcanic channels, it may be noticed that they in general show a strong
grade in whatever direction thev flowed.

Perhaps the first fact that attracts the attention when the grade sheet
is studied is the remarkably steep grades prevalent. Down near the
great valley, as well as high up in the mountains, grades of from 60 to
100 feet and above are noticed; these are certainly not the grades which
would be expected in rivers depositing gravel in a country which, as
shown by the topography, had been subjected to a long-continued
erosion.

A further study will, however, show that while all of the transverse
principal channels have a strong grade, most of the principal forks flow-
ing in a direction about parallel to the trend of the range have a com-
paratively slight grade. The most striking instance of this is furnished
by the Neocene South Yuba from Badger hill to You Bet. The sudden
increase in grade from Waloupa to Dutch Flat (Thompson hill), where
the river suddenly turns from a longitudinal to a transverse direction,
illustrates this relation of grade and direction in an especially suggestive
manner. A similar contrast is noticed at the junction of the North
Bloomfield with the Grizzly Hill channel, and the course of the South
fork of the American from Pilot hill to Diamond springs shows a strong
tendency in the same direction. The grade of the longitudinal Forest
City tributary is considerably less than that of the main river into which
it empties, and the uppermost course of the Neocene Middle Yuba from
Milton to Meadow lake in a longitudinal course slows a much lower
grade than would be expected.

This generalization does not apply to all of the principal forks, bow-
ever, for the grade of the important tributary extending from Damascus

20G W. LINDGREN — TWO NEOCENE RIVERS OF CALIFORNIA.

to Michigan Bluffs is as heavy as that of the main river running in a

nearly cast-west direction; nor does it apply to the lesser tributaries.
The one emptying into the upper North fork of the American river near
Russian ravine has a very heavy grade, although running nearly parallel
to the range. The same is true of the fragment of channel exposed south
of Cisco. The ( lanada Hill-Sterrett channel offers an interesting instance
of a steep Neocene gulch or creek running for some distance in a north-
easterly direction.

Another fact deserves notice. The North Bloom field*channel up to
Moores Flat and the Dutch Flat-Lowell hill channel, in a corresponding
position further south, show extremely heavy grades which scarcely can
he sufficiently accounted for by harder rock-masses encountered. The
North Bloomfield channel cuts with a heavy grade through the same
siliceous slates over which the Blue Tent channel flows with a very slight
grade. A mass of hard rock is met with at Dutch Flat, hut between
Dutch Flat and Lowell hill the slates are not particularly resistant.

Taking in consideration the fact that there is no essential difference in
the character of deposits between the longitudinal and transverse rivers,
the relation of grade and direction explained above is a strong argument
in favor of a considerable increase in the slope of the Sierra since the
time the ante-volcanic Neocene rivers flowed over its surface.

This uplift was probably gradual and extended over a long period,
beginning at or shortly after the initiation of volcanic activity. The
evidence from the region of the first summit in the territory here described
appears to show that this disturbance ended about the time of the last
great lava flows, and that while subsequent elevation might have taken
place it has been of slight importance. It is necessary to add, however,
that the region of the second summit has not yet been sufficiently exam-
ined to warrant the extension of the last statement to the whole range in
this latitude.

If this increase in slope be attributed to a simple tilting of a rigid
block, such as advocated by Professor Le Conte, if I understand him
correctly, a reduction of the channels to fairly uniform grades is impos-
sible; for if the range be supposed to be tilted downward so that the
transverse channels with slighter grades become nearly level, many of
tic other transverse channels in which gravels have accumulated will
still have a grade of 80 feet or more to the mile. The maximum amount
of tilting to the mile cannot in this case have been more than the mini-
mum grade of the transverse rivers, or from 60 to 7<> feet to the mile.
This would give a maximum increase of elevation of between ."..('.mi and
4,200 feet.

If, on the other hand, the increase in slope has been effected by means

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VARIABLE GRADES EXPLICABLE BY FAULTING. 297

of distributed faults of slight throw or equivalent plastic deformation, as
held by Mr G. F. Becker* the grades of the Neocene rivers might more
easily be reduced to somewhat uniform figures by assuming that along
distances showing exceptionally heavy grades a more intense faulting
or deformation has taken [dace. The considerable and even steep grades
of some longitudinal channels show, however, that even by this means
the rivers cannot be reduced to gentle and uniform grades.

The vertical curve of the present Neocene channel- would appear to
offer a criterion by means of which it might be ascertained whether, in
addition to the general uplift, the flank of the Sierra has been materially
deformed. The grades of two principal forks of the old rivers which in
general have a transverse direction have been plotted in plate 9, the
distances being taken along the curves of the streams. In the same
plate the vertical curve of one ^>l the modern forks has been constructed
in order to serve for comparison. The two curves in the upper part of
the plate cannot be directly compared, and the difference in the ordi-
nates does not directly indicate the amount of recent erosion, for the
curve of the Neocene river is somewhat longer than that oi the modern
equivalent. It should first be noticed how regular is the curve of the
recent river in spite of the fact that the country drained by it is only
in the earliest stages of baseleveling. It is, strictly speaking, composed
of two curves, the junction of winch nearly coincide- with the lower limit
of glaciation. The existence of the upper curve must be referred to the
ice-cap protecting the higher part of the mountains from active erosion
during a large part of the Pleistocene."*

If the modern river curve shows such regularity it would be natural
to expect that that ^>t the Neocene river, which represents a more ad-
vanced stage of base-levelling, should be still more so. But the plotted
curve of the Neocene Middle Yuba river does not correspond to the
normal curve of erosion. Instead, it appears to be composed of two
curves with the convex side upward. I think this convexity, winch
cannot be explained by differences in the resistance of the rock-masses
over which the river flows, must he due to a deformation nf the surface
during the uplift of the Sierra. The most pronounced departure from
the normal curve of erosion results from the present steep grades of the
Neocene channels near the valley. This is marked in both the profiles
given and must. I think, be regarded as indicating a subsidence of the por-
tion adjoining the sediment-filled trough of the meat valley relatively
to the middle part of the range, or a rise of the latter relatively to the
former. Another deformation would appear to have taken place in the

♦Bull. G-eol. Soc. Am . vol. 2, pp. iJ4 and 73; also idem, vol. 4. p. ■
fSee G. F. Becker: Bull. Geol. Soe. Am., vol. 2. p.

XLIV— Bull. Geol. Sue. Am., Vol. 4. 1S92.

298 W. LINDGREN — TWO NEOCENE RIVERS OF CALIFORNIA.

upper part of the first profile, while that of the second profile seems
more like the oormal curve of erosion.
It is evident that if, besides the deformation, a general increase in the

slope has taken place the curves do not represent that deformation quite
correctly, for a diminishing of the slope would affect the grades of the
different sections differently according to their angle with the trend of
the range. On recalculating the grades for a general decrease in the
slope of 50 or 60 feet to the mile it is found, however, that the peculiar
convex forms of the curves remain as before or even are slightly more
accentuated.

Although the present steep grades of the old Neocene channel can thus
be shown to have resulted to a considerable extent from elevation and
deformation, it does not follow that the Neocene river system had very
slight grades throughout. On the contrary, I believe that a careful study
of the Neocene topography, as shown in valley slopes and cross-sections,
which hardly can have been influenced by subsequent deformation and
certainly have not been faulted to any notable extent, will lead to the
conclusion that the Sierra Nevada, before the accumulation of gravels
began, was a mountain range greatly worn down by erosion, but not
reduced to a baselevel of erosion. It cannot even on the whole be
regarded as a peneplain, above which isolated and more resistant hills
projected ; the declivities and irregularities of the old surface are too
considerable for that, nor are the projecting hills invariably composed of
the hardest rock-masses.

Conclusions.

The observations recorded in this paper appear to prove conclusively
that the Sierra Nevada in Neocene times, in the watersheds of the Yuba
and American rivers, formed a mountain range as distinct as that of
today, and that its first summit in general coincided with the corre-
sponding modern divide. They further appear to prove that the grades
of the remaining Neocene gravel channels are to a certain extent deter-
mined by the directions in which the}' flowed in such a way as to strongly
suggest that the slope of the Sierra Nevada has been considerably in-
creased since the time when the Neocene ante-volcanic rivers flowed
over its surface. It finally appears probable from a study of the grade
curves of the remaining channels that the surface of the Sierra Nevada
has been deformed during this uplift, and that the most noticeable defor-
mation has been caused by a subsidence of the portion adjoining the
great valley relatively to the middle part of the range.

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BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA
VOL. 4, PP. 299-304, PL. 10 JULY 31, 1893

SOME MARYLAND GRANITES AND THEIR ORIGIN

BY CHARLES ROLLTX KEYES

(Bead before the Society December SO, 1892)

CONTENTS

Page

The Granites 299

Where found in Maryland 299

Their niinera Iridic Composition 300

Four Types represented 300

Origin of the ( Jranites 300

Two Theories advanced 300

Localities favorable for < >bservations 300

Inclusions and their < !< mtacts 301

Proofs of their eruptive Nature 302

a. Their field Relations 302

b. Their Inclusi< >ns 303

c. Their contact Phenomena 303

d. Microscopic Examinations 304:

The Granites.

Where found in Man/loud. — The granitic rocks of Maryland have lately
received special attention, both microscopically and in the field. They
occupy small areas, a dozen or more in number, scattered through the
eastern part of the central zone of the state, known as the Piedmont
plateau. This belt is essentially a crystalline one, made up almost en-
tirely of gneisses, which are broken through in numberless places by
gabbros, pyroxenites and granites, and other closely related types of
igneous rocks.

The different areas may be known from the chief places within their
respective borders. They are Port Deposit, Texas, Windsor road, Relay,

XLV-Bcix. GEor,. Soc. Am., Vol. 4, 189U. (290)

300 C. R. KEYES — MARYLAND GRANITES AND THEIR ORIGIN.

Sykesville, < ruilford, < rarretl park, Woodstock, [lchester, Ellicotl City and
Dorseys Run.

Tin ir mineralogic Composition. — Microscopically the rocks under con-
sideration are composed largely of quartz, feldspar and mica, with acces-
sory plagioclase, microcline, magnetite, apatite zircon, epidote, allanite,
hornblende, sphene and often some other minerals.

Four Till"* represented. — Aside from their structural phases, the Mary-
land granites comprise four types : binary granite, granitite, hornblende
granite and allanite-epidote granite. Each has been fully described in
another place.

Origin of the Granites.

Two Theories advanced. — Regarding the origin of granites in general two
leading theories have been advanced. One considers a granite as the
last stage in the metamorphic change of mechanical sediments. With
the other a granitic mass is regarded as the product of the gradual
cooling of an acidic molten magma, and it is commonly supposed that
the cooling takes place under pressure.

Recently great stress has been laid on the metamorphosing influences
of orographic movements in disguising the original character of rocks,
making eruptives more and more like sedimentary deposits, and clastic
beds more and more like massives. But without entering into a discus-
sion of the general subject, it is intended here to merely set forth some
of the proofs that point to the eruptive origin of certain of the Maryland
granites. That these particular rocks are really eruptive in character
has been seriously questioned by some investigators, while by others the
eruptive character is denied.

Localities favorable for Observations. — Perhaps the most favorable places
for observing phenomena hearing upon the origin of certain of the Mary-
land granites are at Dorseys Run station, Woodstock, and Sykesville. all
on the main line of the Baltimore and Ohio railroad a few miles west of
the city of Baltimore.

At the first-named locality an excellent section has been exposed by a
recent railway cutting. Here a dark-colored gneiss is found penetrated
by a light-colored granitite. Huge blocks of contorted gneiss, often 10
to 20 feet across, and numerous smaller angular fragments are embedded
in the massive granite. Souk.' of the gneiss blocks are twisted and bent,
to all appearances through movement when the granite was in a viscous
state. Very light-colored granite dikes also cut in various directions.
Chemical analyses show the dikes to he very much more acidic than
either the gneiss or the massive granite.

ABUNDANCE OF INCLUSIONS. 301

At Woodstock similar irregular blocks of gneiss ;ire abundant in the
granite.

Inclusions and their Contacts. — From Sykesville many inclusions have
been obtained in the granite a few rods below the railroad station, where
a quarry has been opened. Recently great quantities of the rock have
been removed for paving-blocks. During the progress of the work large
numbers of inclusions of foreign rocks have been brought to light in the
granite, furnishing indisputable proof of the eruptive origin of the granitic
mass at this locality.

The inclusions found here consist of irregular fragments of all sizes and
shapes, from minute pieces up to blocks of large size. Among the various
fragments noted may be mentioned those which were evidently origi-
nally limestone, soapstone, pyroxenite, vein-quartz, hornblendic and
biotitic gneisses. Both with the naked eye and in thin slices under the
microscope characteristic contact phenomena are noticeable, similar
in all respects to those observed where molten rocks and calcareous
sediments or liquid lavas and certain crystallines have been brought
together.

The inclusions derived from the limestone appear as thin yellow slabs
from one to several centimeters in thickness and of various sizes. Four
distinct zones are readily recognized, macroscopically, in the inclusions
of this class : (1) The median portion is tine-grained and lemon-yellow
in color. It is surrounded by (2) a narrow band usually 2 to 3 milli-
meters in thickness, white in color, and apparently composed chiefly of
minute grains of quartz. Then comes (3) a very small, fine-grained, dark-
colored shell of varying thickness, containing abundant small garnets up
to one millimeter in diameter. In many cases this layer is so thin as to
be scarcely noticeable. It shades off rather abruptly into (4) the typical
granitite of the area.

Microscopically the four zones are even better differentiated :

The first of these zones is found to bea typical lime-silicate hornstone ;
the second is made up almost entirely of fine, allotriomorphic quartz,
while the third belt is a fine-grained mixture of quartz and biotite, with
small garnets.

Beside the limestone fragments there are abundant inclusions of soap-
stone, vein-quartz, biotitic and hornblendic gneiss. All of these rocks
are well represented several miles to the eastward of Sykesville, where
they dip to the west at a considerable angle. In the case of the two
latter especially, the outside is usually changed considerably for a dis-
tance of about one centimeter. The interior of the gneiss pieces is practi-
cally unmetamorpbosed. It is much lighter in color than the contact

Q

U2 C. R. KEYES — MARYLAND GRANITES AND THEIR ORIGIN.

border. The constituents have undergone much crushing and the feld-
spars arc scarcely recognizable. The biotite is nearly all bleached, and
chlorite is very abundant. There is also presenl secondary epidote and
muscovite, and a few larger decomposing cubes of pyrite are scattered

through the mass.

The margin of the gneiss blocks is dark colored and much finer in
grain. No traces of pressure are noticeable, and apparently it has been
completely recrystallized. Biotite is very abundanl in small Hake-.

oriented in the direction of foliation. A little plagioclase and orthoclase
occur, and also small quantities of pyrite.

Proofs of their eruptive Nature. — The proofs thatthe granites in question

are eruptive in nature is deduced from several different and independent
sources :

a. From field relations.

6. From inclusions.

c. From contact phenomena.

d. From microscopic examinations.

a. Their field Relations. — As stated elsewhere, the eastern half of the
Piedmont region consists chiefly of gneisses broken through in numerous
places by undoubted eruptives, such as gahbro, diorite and pyroxenite,
until these rocks occupy fully one-half of the present exposed surface
of the district.

Now, a careful tracing of the granites shows that they have cut in-
discriminately across the igneous rocks mentioned as well as the gneiss,
passing uninterruptedly from one petrographically distinct mass to
another. In other words, the acidic types of crystallines to all appear-
ances seem to he younger in age than the gabbros and the most basic
rocks, as if they too had broken through all the other eruptives. Near
some of the granitic masses, true granitic and felsitic dikes are clearly
defined, which would ordinarily he regarded a- apophyses of the main
body were the rock regarded as an eruptive. Furthermore, at Dorseys
Run station, for instance, large exposures show the granite forced
between and spreading widely apart enormous layers of twisted and
puckered gneiss: while at Woodstock lucre blocks of gneiss are com-
pletely inclosed in the granite.

As already remarked, the line of contact between the granite and the
contiguous rock is seldom determinable exactly, on account of profound
superficial decay. Vet occasionally artificial excavations into the acid
rock reveal.- clearly such contacts. A good example is that found at
the new quarry opened about two mile- northwest of Garrett park,

CHARACTER OF THE INCLUSIONS. 303

where the line is very sharply defined between the granite mass and the
adjoining soapstone belt.

b. Their Inclusions. — Perhaps one of the most conclusive proofs of the
eruptive nature of some of the Maryland granites is the occurrence in
the masses of large numbers of inclusions — fragments of foreign rocks,
both sedimentary and eruptive. These have all been described more or
less at length in another place, to which reference may be made for fuller
details. At Sykesville, where they occur so abundantly, the irregular
angular fragments and blocks of all sizes are identical with rocks in the
neighborhood.

In most of the cases observed, the interiors of the foreign pieces are
scarcely altered at all, though the exterior forms more or less completely
metamorphosed shells of varying thickness. The Woodstock and
Dorseys Run granites show similar phenomena equally well or even
better. In both instances, blocks of highly puckered gneiss are very
prominent, and they all possess narrow marginal borders of dark, fine-
grained, completely changed rock, which contrasts sharply with the light-
colored surrounding granite.

Certain outcrops observed in the vicinity of Garrett park furnish
good illustrations of the same kind, though here the granite has been
squeezed considerably more than in the other ease mentioned. At this
place there is one exposure showing numbers of small lenticular masses
of a black color which might easily be taken for inclusions but for their
regularly rounded outlines. These are doubtless basic secretions which
developed in the acid magma.

c. Their contact Phenomena. — For reasons elsewhere explained, the
contacts between the granitic masses and the adjoining rocks are rareby
seen to advantage. The invest igation < >f the contact zones have therefore
been carried on largely with the inclusions. This lias been very satis-
factory, on account of the variety of foreign rocks represented and the
abundance of the fragments. In most of the fragments it is only the
outside which is changed to the depth of from two to four centimeters or
more, the interior still often preserving the rock in its original character.
so that no doubt arises concerning its composition and structure previous
to its embedding in the granite.

The contact zones are in all respects identical with the contact belts
of other localities where acid eruptives have pushed up against the same
kind of rocks.

Chemical analyses of the unaltered inclusions, the metamorphosed
shells, and the surrounding granites show that the altered shells have an
acidity intermediate between the inclusions and the granites.

304 C. !;. KEYES — MARYLAND GRANITES AND THEIR ORIGIN.

These proofs of eruptive origin of the Maryland granites are quite
similar to those which Barrois* has formulated from the granites of
Rostrenen.

d. Microscopic Examinations. — Aside from the ordinary microscopic
characters indicative of cooling from fusion, certain of the granites under
consideration show some additional phenomena pointing to the same
end. These are Large grains, micropegmatitic Lntergrowths of quartz and
feldspar, rounded through magnatic corrosion apparently and having
the characteristic embayments so commonly associated with cases of
this kind.

*Ann. de la Soe. geol. du Nord, t. xii, p. 106, 1885.

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA
Vol. 4, pp. 305-312 July 31, 1893

EPIDOTE AS A PRIMARY COMPONENT OF ERUPTIVE ROCKS

BY CHARLES ROLLIN KEYES

{Read before the Society December ■'><>. 1892)
CONTENTS

Page

The epidote-bearmg Rocks 305

Occurrence and eruptive Origin 305

Microscopic Characteristics 305

Comparison of Granites with Granitites 306

Allanite 306

The mineralogic Associate of Epidote •">|><>

As a rock-forming Mineral reviewed 306

Epidote : 308

Its Abundance in Maryland < rranite 308

Its microscopic Appearance 308

Its ( JrystalL igraphy ' 308

Its Origin 309

Summary • 311

The epidote-bearing Rocks.

Occurrence and eruptive Origin. — Very conclusive evidence has been
found recently showing that certain granites of Maryland are eruptive in
origin. The granitic masses occur in irregular bosses breaking through
gneiss, gabbro and other crystalline rocks. In the central part of the
state, at Dorseys Run station, Woodstock, Ilchester and Ellicott City,
the acid eruptives are true granitites. granular aggregates, consisting
essentially of quartz, feldspar and black mica, with considerable amounts
of epidote and allanite as accessory constituents. These rocks vary con-
siderably in color, from dark iron-gray to nearly white, according to the
percentage of ferro-magnesian silicates they contain.

Microscopic Characteristics. — Under the microscope thin sections some-
times show that the incipient stages of dynamic metamorphism have set
in. In other occurrences the granites show little or no signs of mechani-
cal deformation. The occurrence of the two prominent accessory min-

(305)

306 C. It. KEYES — EPIDOTE IN ERUPTIVE ROCKS.

erals in the Maryland acid rocks was firsl noted by Hobbs,* who had
under consideration the porphyritic granites of the last two localities just

mentioned. In the published notes particular attention is called to the
isomorphous intergrowths of epidote and allanite. Since the appearance
of the paper alluded to considerable additional materia] has been ex-
amined, both from the Ilchester and Ellicott City districts, besides three
other places.

Comparison of Granites with Granitites. — In all their general characters
the epidote-allanite bearing granites are essentially identical with the
granitites of the region, except as a rule they are more basic and conse-
quently much darker in color. The essential constituents show no note-
worthy differences from the acid components of the typical granitites.
In hand specimens a distinct greenish cast is often quite noticeable. Upon
closer investigation the green specks are f< >und to have frequently a reddish
core. Microscopic examination in thin sections show that the two min-
erals are clear, usually idiomorphic or hypidiomorphic epidote. and
reddish, intensely pleochroic allanite in parallel growth-.

Allanite.

The mineralogic Associate of Epidote. — Ik-fore considering the epidote in
detail a few words in regard to the allanite may not he out of place, as it
is intimately associated and closely related chemically.

As a rock-forming Mineral reviewed. — As a rock-forming mineral, allanite
has long been regarded as one of the rarer occurrences. Within the pasi
few years, however, hidings and Cross f have found this silicate of the
rare earths widely distributed among acid eruptives, in some rocks form-
ing an important accessory. Among the rocks in which the mineral
under consideration was found may he mentioned gneiss, granite, quartz-
porphyry, rhyolite, diorite, porphyrite, andesite, dacite and others. The
localities in this country where allanite has been found to form a rock
constituent are numerous, and are even widely separated geographically.

In Europe the apparent rarity of rock forming allanite has made the
observed occurrences somewhat noteworthy. There is a further interest
centering around this mineral which is of no little importance from a
historical point of view also. It is the fact that the presence of allanite
in granite formed one of the chief arguments againsl the theory of the
igneous origin of granite in the long-continued controversy that took
place during the second quarter of the present century. The inability of
this mineral to withstand a temperature higher than a dull-red heat

* Johns Hopkins University Circulars, no. 85, 1888, i>. 70,
fAm. Jour. Sci . 3d ser., vol. sxx, L885, p. L08,

WIDE DISTRIBUTION OF ALLANITE. 307

without changing its physical character was evidenced as a strong proof
against the igneous origin of granite. This objection was met by
Scheerer* as early as 1842, in a paper entitled " Erste Fortsetzung der
Untersuchungen iiber Gadolinit, Allanit, und damit verwandte Mine-
ralien," read at Stockholm before the Society of Scandinavian Naturalists.
Some years later the same writer f discussed an aqua-igneous theory of
the origin of granite, and suggested that owing to the presence of water
the magma may cool down considerably below the temperature neces-
sary for solidification under the conditions of ordinary dry fusion, and
thus allow minerals which cannot endure great heat to crystallize out
before other constituents more difficult to fuse by the simple dry method.
Both Elie de Beaumont and Daubree and later others have confirmed
this theory experimentally.

Since Scheerer's time a number of writers have noted the occurrence
of allanite in various igneous rocks. Chief among these allusions may
be mentioned those of Blomstrand,'| von Fritsch,§ Vom Rath . j | Liebisch*
Tornebohm,** Iddings and Cross, ft Michel-Levy and Lacroix, H
Hobbs, §§ and Lacroix. ||

In Maryland, Hobbs appears to have been the first to call attention to
the presence of allanite in the rock of the state. The specimens espe-
cially studied were from certain granites and porphyritic granite from
the immediate vicinity of Ilchester. Since the announcement of these
occurrences similar allanitesand allanite-epidote intergrowths have been
found at other places — at Dorseys Run station, and in less abundance
at Woodstock, and on the Gunpowder river, northeast of Baltimore.
Since the appearance of the first note on the allanite-epidote intergrowths
from the porphyritic granite of the Ilchester district some doubts have
been raised as to whether the exterior clear portions of the grains are not
in reality the same mineral as the interior dark parts, but differing
slightly chemically. For this reason the author ^]~*| just referred to reex-
amined some of his earlier preparations and after the complete isolation
of the dark central allanite had a chemical analysis made of some of the

*PoggendorfFs Annalen der Phy. u. Chemie, lvi Band., 1842, p. 479.

fBuI. Soc geol. de France, 2d ser., tome i\\ 1847, p. 468.

JOefvers. af akad. Forhandl., no. 9, 1854, p. 290.

< Zeitsch. d. d. geol. Ges., xii Band., 1800, p. 105.

I] Zeitsch. d. d. geol. Ges., xvi Band., 1SC4, p. 255.

1 Zeitsch. d. d. geol. Ges., xxix Band., 1877, p. 725.

**Geol. Foren i Stockholm.Forh., vi Band., 1882, p. ls:,: also, Vega Exped., vol. iv, Stockholm,
1884, p. 115.

ft Am. Jour. Sci., 3d ser., vol. xxx. 1885, p. 108.

JJBul. Soe. min. de France, tome xi, 1888, p. 05.

H Johns Hopkins University Circulars, no. 05, 1888, p. 70; also, Am.. Jour. Sci., 3d ser.. vol. xxxviii,
1889, p. 223.

Illl Bui. Soc. min. de France, tome xii, 1889, p. 139.

1ft[ Am. Jour. Sci.. 3d ser., vol. xxxviii, 1889, pp. 223-228.

XLVI— Bull. Geoi,. Soc. Am., Vot,. 4, 1892.

308

('. K. KEYES — EPIDOTE IX ERUPTIVE ROCKS.

epidote fragments, which show a very close correspondence with epidote
of other Localities, particularly Ludwig's specimen from the Untersulz-
bach. The following are the results obtained from the Maryland speci-
mens by Dr Eillebrand, of the United States Geological Survey, and
from the Tyrolean locality by Ludwig. The Ti02is probably due to the
presence of sph,ene, which was not separated from the powder completely :

Maryland.*

Untersulzbach.

SiOz

37.(>:;

18.40

3.78

15.29 |

0.31
22.93
0.31
0.44
2.23

37.83
22.63

15.02
0.93

23.27
2.05

A1,A;

Ti< )

Fe,0

Fe()

MnO

CaO . .

MgO

PA

H20

101.32

101.73

Epidote.

■ Its Abundance in Maryland Granite. — The epidote of the allanite-bearing
granites of Maryland is frequently so abundant as to give a decided
greenish cast to the color of the rock. Under a pocket lens the yellowish-
green mineral is seen in small sharply hounded crystals or irregular
grains, showing glistening surfaces of fracture' and usually containing a
central reddish interior, which already has been shown to be allanite.

Its microscopic Appearance — Under the microscope the epidote usually
appears in sharply denned crystals or grains enveloping reddish grains of
allanites, with which they are strictly isomorphous. Twins have not
been observed, though the included mineral is often twinned. The sec-
tions are transparent, colorless or slightly yellowish, with imperfect
cleavage. The pleochroism is quite marked, a being colorless or very
faint yellowish; t) light yellow, often tinged with green; r greenish
yellow. The absorption is r > ft > a. Interference colors brilliant.
The plane of the optic axe- is perpendicular to the cleavage and direction
of elongation. These characters, together with the chemical analysis
given, correspond in all particulars with those of rock-making epidote.

Its Crystallography. — The simple crystals of epidote are usually quite
small, and commonly have their crystallographic planes much better
denned than in the other cases. The most frequently observed faces

Si e ilso Bui. 64, U. S. Geol. Survey, p. 42.

CRYSTALLOGRAPHY OF THE EPIDOTE.

300

are OP j 001 [ , «. P s j 100 J , 2 P oo I 201 J , oo P So j 010 J , and
occasional]}' two small hemipyramids, probably + P Til and — P

111 . The crystals, as well as many of the intergrowths with allanite,
occur as a rule completely surrounded by biotite.

,?<•

Figure I.— Microscopic Crystal of Epidote in
Ellicott City (Maryland Granite.

Fi<.i be 2. — Epidote in Ellicott City
Granite.

An interesting occurrence of epidote is as an inclusion in sphene,
along with an apatite and a greenish mineral having all the optical and
physical characters of pleonaste. In other masses the sharply bounded

Figube 3.— Epidote in Woodstock
(Maryland) Granite.

Figube 4.— Epidote in Wood ' <
Granite.

epidote comes in contact with unaltered feldspar, quartz and biotite
grains and gives outlines to them.

Its Origin. — The origin of the epidote in the granite rocks under con-
sideration is of great interest. Rock-making epidote has been regarded

310 C. U. KEYES — EPIDOTE IN ERUPTIVE ROCKS.

almost universally as never forming a primary constituent of eruptives,
or Archean masses, while as a characteristic ingredient it is abundantly
developed in metamorphic gneisses, schists and phyllites. It is also a

common product of both acid and basic rocks containing feldspar. The
occurrence of epidote in acid eruptives has occasioned considerable
discussion. Among the earlier references may be mentioned certain
papers of Becher* and Blomstrand,f while the principal allusions to
the subject during the past decade have been made by Tornebohm,J
Geikie.§ Rosenbusch,|| Hobbs,^ and Adams.-*

The general consensus of opinion as derived from the literature
referred to has been against the idea that the epidote was original in
any of the cases mentioned. Hobbsjf who was the first to study the
Ilchester (Maryland) granite, was inclined to believe that the epidote
was of metamorphic origin. Very recently Adams|| has investigated
some epidote-bearing granites from Alaska, in which the mineral alluded
to is thought to result from the recrystallization of certain of the rock's
constituents after the original solidification of the mass. The epidote
is regarded as "having grown into the surrounding minerals b}T first
sending out little arm-like extensions from its substance which subse-
quently met one another, in this way including some of the foreign min-
erals, which may or may not finally disappear " (page 349). Parallel
growths of allanite and epidote are explained by the former being-
regarded as " a primary mineral around which the epidote would nat-
urally crystallize, if any were developed in the rock, the two minerals
being isomorphous " (page 350).

In his " Contributions a l'etude des gneiss a pyroxene et des roches a
wernerite"§§ Lacroix has figured and described some interesting occur-
rences of isomorphous growths of epidote and allanite in the amphibolic
gneiss of Geffren-en-Roscoff. They are considered analogous to Ilches-
ter examples with which he has compared them. These growths are
also reported from certain rocks of Finisterre, Norway, and Waldviertel,
the epidote in all these instances being regarded as primary (page 353).

The association of certain of the allanites and epidotes in the granites
of Maryland is so intimate that there can be but little doubt that both

♦Ueberdas Mineralworkomen in Granite von Striegan, u. /.. w. (Boslau).
tOefvers at', akad. Forhandl., no. '.'. 1854, p. :»6.
JGeol. For. i Stockholm Forhandl., vi, 1882, p. 245.
gQuar. Jour. Geol. Soc . vol. xxxix, p. :a 1.

Mik. Phys., i Band, L885, p. 498.
* Johns Hopkins University Circulars, no G5, 1888, p. 70; also Am. .lour. Sri.. v<.l. xxxviii. 1889,
pp. 223-228.

** Canadian Record Science, 181)1, pp. :;ll - 18

tt Loc. fit.

XX Loc. fit.

g§Bul. Soc. min. de France, torn.' xii. 1889, p. 139.

SUMMARY.

311

minerals were formed under the same .physical conditions, so that any
remarks upon the origin of the one would apply equally as well to the
other. In attempting to determine whether or not these minerals are of
primary or secondary origin in granitic rocks, the evidence must neces-
sarily be based in great measure upon the observed association with the
other minerals. Allanite, as has already been stated, is comparatively
easily fusible, and on this account it long has been quoted as one of the
proofs against the igneous origin of granite; but its occurrence in such
rocks as unaltered porphyrite, quartz-porphyry, dacite, andesite, and
rhyolite masses whose eruptive nature, as shown by hidings and Cross*
is not to be questioned, shows conclusively that this mineral actually
does form in a molten magma.

Furthermore, the epidote occurs included in well-defined crystals of
sphene whose primary character cannot be doubted; besides, it is not
uncommon to find sharply denned crystals completely mantled by bio-
tite, along with similar inclusions of zircon, apatite and magnetite.
There is further evidence pointing toward the original character of the
epidote in the occurrence of broken crystals of allanite-epidote inter-
growths, into the open fractures of which biotite has formed. To all
appearances these fractures are protoclastic in nature. Finally, crystals
of epidote or isomorphous growths of epidote and allanite, with the
crystallographic planes well defined, are found giving shape to the unal-
tered feldspars, quartz ami mica.

Summary.

In summing up the facts already presented it would appear that the
evidence of the primary occurrence of epidote in the eruptive rocks is
essentially the same as that for allanite. Attention has been called
to the fact that allanite. though easily fusible, is now known to be widely
distributed, and is often an abundant accessory in such rocks as dacite,
porphyrite, diorite, quartz-porphyry, rhyolite and others the igneous
nature of which cannot be questioned. All physical obstacles as to its
primary origin are manifestly removed. The evidence, therefore, in any
particular case that this mineral is either primary or secondary must be
derived largely from the study of its associations with other minerals.

Now the epidote of certain of the Maryland granites is found in
isomorphous growths with allanite, as well as in separate well-defined
crystals. Both occurrences are found in sharply bounded individuals,
and the following remarks apply to the intergrowths and single crystals

* Am. Jour. Sei. 3d ser., vol. xxx, 1889, p. 109.

312 C. R. KEYES — EPIDOTE IN" ETtUPTIVE KOCKS.

alike. That those must be original constituents, and not secondary
products, is indicated by —

1. Its presence in perfectly fresh rocks or rock but slightly altered
by orographic movements.

2. Its inclusion in sphene, one of the earliest <• ponents to crystal-
lize out from the molten magma.

3. Its occurrence with sharply defined crystallographic i';\rr>, com-
pletely mantled by clear, unaltered biotite or feldspar, and giving shape
to some of the essential constituents of the granite.

4. Its presentation in long crystals, broken and bent, and the inter-
stices and parted cracks filled with biotite, and often continuous with,
and optically oriented the same as, the surrounding black-mica crystals,
whose shape is partially given by the epidote. These fractures appear
without doubt to be protoclastic in origin.

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA
Vol. 4, pp. 313-332 August 4, 1893

RELATIONS OF THE LAURENTIAN AND HURONIAN ROCKS

NORTH OF LAKE HURON*

BY ALFRED E. BARLOW

{Read before the Society December 30, 1892)

( '< INTENTS

Page

Introduction 314

The Huronian Rocks 314

The Laurentian Rocks 315

l leneral Course of the Contact on Lake Huron 315

The Lake Huron Localities in Detail 316

Killarney Village :;ii;

Huronian and Laurentian Rocks found there described 310

Extent of the Huronian 317

Beaver, Fox and Balsam Lakes — The Rocks and their Contacts :!17

Character, Contact and Relation of the Rocks of Three-mile Lake Ml 7

, Transitional Rock-masses between Three-mile and Brush Camp Lakes. . . 318

The Contact on Brush ( 'amp Lake 318

The Quartzite and Gneiss of Crooked and Johnny Lakes 318

< roschen Township and Lake Panache 31S

Direction and Extent of the Contact 318

Quartzite and its microscopic Examination Mis

Disturbance causes Change of Strike 319

Alteration in Character of Rocks accompanies Change of Strike 31!)

Microscopic Examination of altered Quartzite 311)

Bedding Planes of and intrusive Masses in the Huronian mica Schists. 320

Microscopic Examination of Quartzite with granitoid < ineiss 320

Other Localities 321

Wavy Lake 321

Direction of the Contact 321

( 'haracter and Relation of the Gneiss and Quartzite 321

Microscopic Examination of the (ineiss 321

* 'leavage Planes and embedded Quartzite 322

Chiefs Lake 322

The Contact 322

The Rocks 322

* Published by permission of the Director of the Geological Survey of ('ana da.
XLVTI— Bur.L. Geol. Soc. Am., Yor. 1, ls:i_>. l;'l^>)

314 A. E. BARLOW — LAURENTIAN AND HURONION ROCKS.

Pag

Broder Township 322

Direction and Extent of the Contacl 322

Microscopic Examination of I [uronian Schist 322

Microscopic Examination of the < hieiss 323

Character of the I tucks near the Line of ( lontact 321 I

Dell Township, I >aisy and Baby Lakes and Lake Alice 32-J

Direction and Extent of the ( !ontact 324

Microscopic Examination of foliated < rneiss - 324

Daisy Lake Rucks 324

Microscopic Examination of the Quartzite 324

Rocks between I >aisy and Baby Lakes 325

Microscopic Examination of Contact Rock 325

Rooks between Baby and Alice Lakes 325

Wahnapital River 326

Contact indicated by ( lharacter of Rocks 326

The Huronian Representative 326

Rocks of the Contact between ('artier and Straight Lake Stations 327

Two Islands near Thessali >n 327

Contact previously described by < )thers 327

Difference in the Conclusions of the Author and other Writers recited. 327

( (inclusions and Facts supporting them 330

Introduction.

In this paper, which is a revision and extension of one published in
the American Geologist of July, 1890, the writer proposes to bring
forward some observations on the nature of the contact between the
Huronian rocks of Lake Huron, described by Logan and Murray, and
the Laurentian gneisses, which it is thought have an important bearing
on the question of the origin and relative age of the latter.

THE HURONIAN JR OCA'S.

The rocks of the Huronian area to the north of Lake Huron are made
up of a series of quartzites, graywackes, slate conglomerates, day slates
bydromica, chloritic, and hornblendic schists, greenstones and some
bands of cherty limestones or dolomites. Frequently these rocks show a
pyroclastic origin, and tuffs and breccias arc very commonly met with.
The majority of the clay slates have the appearance of being very little
altered, except in contact with the greenstone and other igneous rocks,
and present in greal part the same appearance as when hardened from
the original soft sediments. The quartzites, graywackes and slate con-

THEIB CONTACTS. 315

glomerates have all been altered more or less by the secondary enlarge-
ment of the component grains and the deposition of interstitial silica,
and one can frequently obtain specimens showing a perfect gradation
from the loose, friable sandstone to the almost completely vitrified
quartzite, there being every possible phase between these two extremes.
In the vicinity of the gneiss and granite both the quartzite and gray-
waeke are altered into mica schists.

THE LAURENTIAN ROCKS.

The Laurentian to the north of hake Huron is chiefly represented by
gneiss which differs from granite only in being foliated. Frequently
this foliation is quite distinct, though sometimes it is obscure and occa-
sionally it cannot be detected at all, the rock being then indistinguishable
from ordinary irruptive granite. Intimately associated with the gneiss
are certain true granites and syenites, non-foliated and varying in tex-
ture from coarse to fine-grained. Although in many cases there is the
clearest evidence that these granites cut the gneiss, yet for the following-
reasons both may be considered to have had a common genesis :

1. The presence of streaks and lenticular patches of darker-colored
material in the midst of these non-foliated areas, all of which have a
more or less constant direction.

■2. The frequent absence of any sharp line of division I letween the gneiss
and granite, the one passing into the other by insensible gradations.

3. The occurrence of dikes and veins of pegmatite cutting both the
gneiss and one another clearly belonging to the same period, although
the fact of one cutting the other would seem to indicate a lapse of time,
which in this case was doubtless of small import.

4. Their close resemblance in composition, appearance and behavior.
These masses of granite may therefore be regarded as non-foliated

areas of gneiss, representing simply certain irruptions from the same fluid
magma from winch the gneiss itself has solidified, and although a suffi-
cient time has elapsed to allow of the more or less complete consolida-
tion of the gneiss, yet they represent the same age in geologic time.
The first-formed crust was necessarily thin and weak, so it is not surpris-
ing that the basement complex exhibits such frequent evidence of the
upwellings from beneath of the fluid magma. The non-foliated character
of many of these masses may have been due to their very gradual intru-
sion and the absence of pressure during tin,' process.

Gexeral Cotjrse of the Contact ox Lake Huron.

On Lake Huron the contact between the Laurentian and Huronian
comes out on Killarney bay, a mile and a half north of Killarney post

316 A. E. BARLOW — LAURENTIAN AND HURONIAN ROCKS.

office (Shiboananing). Thence, crossing Lamorandiere bay, it reaches
George lake at the southwestern end. It then appears to pass through
George lake and, following its inlet from Ka-ka-kis lake, crosses the latter
about the center, cutting the western boundary of the township of ( larlyle
about five miles north of * lollins inlet. It then strikes across the country
for about four miles, reaching Brush Camp lake two hundred and fifty
yards north of the Crooked Lake narrows. Crossing two points which
jut out into Brush Camp lake.it intersects the neck of land between
this and Three-mile lake, reaching the latter at its southeastern end.
Continuing through Three-mile lake for about two miles, il crosses the
eastern boundary of the township of Goschen three miles and a half
south of Lake Panache. Throughout this distance of twenty miles the
line of junction runs with gently sweeping curves in a general direction
of N. 60° E. The La Cloche range of mountains ends somewhat abruptly
at Brush Camp lake, for Northeast peak, the highest in the range (1,762
feet above the sea), is but two miles -east of this lake. These hills are
composed of Huronian white quartzite, and are here interrupted by the
gneiss, which occupies comparatively lower ground.

The Lake Huron Localities in Detail.
killauxey village.

Huronian and Laurentian Rocks found then described. — Dr Robert Bell,

in his report* on the geology of the neighborhood of the village of Kil-
larney (Shiboananing), says:

"The village itself stands upon red syenitic granite, which, except at the sides,
has a massive homogeneous structure, hut in a few instances a single reddish or
yellowish green shaly streak an inch or two in thickness was observed, running in
a northeasterly direction. Toward each side the grain of the reck begins to assume
a sort of parallelism or a gneissoid structure. The granite is flanked by a stratified
rock of reddish-gray color, consisting of a tine-grained crystalline mixture of feld-
spar and quartz."

Both rocks have approximately the same northeasterly strike, but
while the Huronian beds are about vertical, the granitoid gneiss dip-
southeast at an angle of 50°. Dr Bell refers this granitoid gneiss to the
Huronian rather than the Laurentian, although he gives no reason for
so doing. The coincidence in direction of the streaks in the midst of the
granite itself, the absence of any sharp Line of division, as well as the
more perfect development of the foliation near the junction of the
Huronian strata, are characteristic features of obscure or non-foliated
gneissic areas.

* Repori Gi I. Survey Canada, 1 870 '77.

LAKE HURON CONTACT LOCALITIES. 317

Extent of the Huronian. — 'The dark feldspathic sandstones and shales
of the Huronian form a triangular patch in the northern part of the
township of Rutherford, and are followed to the north by the vitreous
quartzite of the La Cloche mountains. The base of this triangle on Kil-
larney bay is about a mile in length, while the apex is at George lake,
where these rocks thin out, being replaced to the northeast by the snow-
white quartzite in contact with the gneiss. Mr H. G. Skill, of McGill
Universit}', my assistant for a time, tells me there is abundant evidence
of the irruption of the granitoid gneiss in the alteration and disturbance
of the sedimentary strata, while a band or zone of graywacke in contact
with the gneiss frequently shows feldspathic matter intruded parallel
to the strike.

BEA VER, FOX AND BALSAM LAKES— THE HOCKS AND THEIR CONTACTS.

The shores of Beaver, Fox and Balsam lakes on the route from Lake
Panache to Collins inlet, it was observed, are occupied by a dark
greenish-gray feldspathic sandstone or graywacke which occasionally
contains pebbles of a coarse, red granite. The strike of this rock is in
general nearly east and west, and the dip southerly at a high angle, but
as the rock is often massive this cannot always be determined with cer-
tainty. In the northeastern part of Balsam lake a small area of gran-
itoid gneiss is exposed, hut the immediate contact with the enclosing
graywacke was not seen, owing to an intervening marsh.

CHARACTER, CONTACT AND RELATION OF THE ROCKS OF THREE-MILE LAKE.

The Huronian rocks continue through Balsam lake and on to Three-
mile lake with a strike of S. 75° E. (dip S. 15° \Y. at a high angle), but
upon entering the latter body of water they quickly curve round first
to southeast, then south, and finally pinch out near their contact with
the gneiss, giving place at this point to the white quartzite of the
La Cloche mountains, the latter rock continuing in juxtaposition with
the gneiss as far as George lake. The graywacke in the northern part
of Three-mile lake shows abundant signs of disturbance ami pressure
and is altered into a dark-gray mica schist, with uneven or lumpy cleav-
age surfaces. This rock is probably the equivalent of the graywacke
exposed in the northern part of the township of Rutherford, having been
cut'out through the intervening space by the irruption of the gneiss.
The contact between the two rocks on Three-mile lake is seen on the
eastern shore nearly two miles south of the inlet from Balsam lake, tin.'
gneiss occupying the southeastern shore and off-lying islands, while the
quartzite forms the mainland to the northwest. The gneiss Is coarsely
crystalline, dark flesh-red in color, porphyritic ; large feldspar crystals

• )

18 A. E. BARLOW — LAURENTIAN AND HURONIAN ROCKS.

being seen embedded in a matrix composed of feldspar, quartz, and mica.
Feldspar is by far the most abundant constituent, and tbe foliation, which
is quite distinct, consists chiefly of a parallel arrangement of the feldspar
crystals. Embedded in the gneiss are patches and strips of highly
altered quartzite, plainly referable to the Huronian quartzite in the imme-
diate vicinity and corresponding in strike with the foliation of the en-
closing rock.

TRANSITIONAL ROCK-MASSES BETWEEN THREE-MILE AND BRUSH CAMP LAKES.

To the northeast of Three-mile lake, and also between this and Brush
Cam}) lake, there appears the interesting phenomenon of a sort of transi-
tion from one formation to the other. At these places a band of gneissic
quartzite occurs which may be due to the fusion of the two rocks in situ
and the absorption or passage of the components of one rock-mass into
the other. Both rocks incline to the southeast, the quartzite dipping
into or under the gneiss.

THE CONTACT ON BRUSH CAMP LAKE.

On Brush Camp lake the immediate contact was seen at three places,
the two rocks in these cases holding the same position as on Three mile
lake, but the line of division is sharp and distinct. At one point on the
north shore a boss of coarse red gneiss was seen protruding through and
disturbing the quartzite, the strike of the latter curving round so as to
conform with its outline.

THE QUARTZITE AND GNEISS OF CROOKED AND JOHNNY LAKES.

On Crooked lake it was observed that four irregularly-shaped patches
of quartzite had been apparently caught up in the gneiss, the contrast
in color between the two being very marked. The largest one of these
on the west shore was triangular in outline, measuring about a quarter
of a mile in length. A mass of the same white quartzite was also noticed
embedded in the gneiss on a small island in Johnny lake, nearly one
mile and a half from the line of junction.

GOSCHEX TOWNSHIP A XI) LAKE PANACHE.

Direction and Extent of the Contact. — From the eastern boundary of the
township of ( roschen thelineof division turns in the direction of X. 20° E.
for about four miles, passing Lake Panache about a mile to the east.

Quartzite <in<l its microscopic Examination. — The shores and islands of
the eastern portion of Lake Panache are occupied by a granular quartzite
of varying shades of gray. Mica in the form of minute disseminated

DISTURBANCE AND ITS EFFECTS. 319

scales and also feldspar are usually present in small quantities. A speci-
men of this rock was obtained from the north shore of Archie bay, four
miles from the contact, which might be regarded as a typical specimen
of the less altered rock. A thin slice of this Avas examined under the
microscope by Dr A. C. Lawson, who says:

"A tine-grained, light yellowish-gray qnartzite, rust-stained in places ; under the
microscope it is seen to be a crashed quartz sandstone; a cataclastic condition is
seen to have been induced upon the original epiclastic grains of quartz ; wavy ex-
tinction is common. There is a rude parallel arrangement of the quartz grains in
long areas, and between the constituent grains is a fine cement which is largely
made up of a felt- work of muscovite. In some portions of the slide this felt-work
of muscovite is mixed with clastic grains of quartz and forms a base in which the
larger clastic grains are embedded. Besides quartz, there is present a notable pro-
portion of fragments of feldspar."

Disturbance causes Change of Strike. — About three miles from the contact
with the gneiss these Huronian quartzites show signs of great disturbance,
and the strike which has hitherto been nearly east and west turns
abruptly to the southeast, this change being still further continued till
the strata have assumed a southwesterly strike, thus corresponding with
the line of outcrop of the gneiss in this direction. A little to the north
of the eastern end of Lake Panache and emptying into it is Gabodin
lake, about two miles in length. At the western end or outlet of this
lake micaceous quartzites were noticed with a strike of N. 75° E., which
curves around quickly, for on the islands in the eastern part of the lake
quartzose mica schists were seen striking N. 15° E., these rocks being thus
conformable with the line of outcrop of the gneiss in its northerly con-
tinuation.

Alteration in Character of Rocks accompanies Change of Strike. — This
rapid change in the strike of the quartzites is accompanied by a very
marked alteration in the character of the rocks themselves. The gran-
ular quartzites and sandstones which have previously shown no further
signs of alteration than a hardening consequent on the addition of sec-
ondary silica are now metamorphosed into very typical quartzose mica
schists. The change is gradual but marked and extends to a distance
of three miles from the line of junction.

Microscopic Examination of altered Quartzite. — Dr Lawson examined two
slides of this qnartzite under the microscope. Of the first he says :

"A light gray, fine-textured, somewhat micaceous quartzite, with occasional
'sheen surfaces' along shear planes. Under the microscope the rock is seen to be
an aggregate of subangular or rounded quartz grains with a subordinate proportion
of feldspar grains, most of the latter being quite fresh and showing the multiple
twinning of plagioclase. Some of this plagioclase is clearly in original clastic grains,
but some appears to be of secondary interstitial growth. Scattered throughout the

o'20 A. K. BARLOW — LAURENTIAN AND HURONIAN ROCKS.

slide are numerous scales of brown biotite and a Less proportion of Muscovite.
Most of these mica scales have a parallel arrangement, but some are seen to have
been developed in the curved lines or areas between the original clastic grains-
Some of the quartz grains show evidence of pressure in the optical tension which
they manifest under crossed nicols. Inclusions are not abundant iu the quartz."

Of the second slide he says :

"A silvery micaceous, very quartzose schist, somewhat rusted, and with strongly
micaceous sheen surfaces. Under the microscope the rock is seen to be composed
essentially of quartz and muscovite. There is a well-marked parallelism in the
arrangement of the muscovite, and the quartz shows distinct cataclastic structure,
wavy extinction arrangement in parallel areas and other crush phenomena'
e\ idently an altered sandstone."

Bedding Planes of and intrusive Masses in tin Huronian mica Schists. — The
planes of bedding of the Huronian mica schists are parallel to the lam-
ination of the gneiss. Both rocks have a strike N. 25° E. and a dip
S. -V>° 10. of 75°, the mien schists dipping into or under the gneiss. Pene-
trating the schists are lenticular sheets and patches of gneissic material
similar in character and composition to the great mass of the gneiss in
the immediate vicinity, to which they may often be continuously and
directly traced. These intrusions of gneiss have disposed themselves
usually in a direction parallel to the bedding of the schists, thus show-
ing the coincidence of the lines of least resistance with the lamination of
the schists. The intrusive nature of these gneissic patches and sheets is
quite evident from even a cursory examination of the relations of the
two rocks in situ, for the foliation of the gneiss composing these intrusions
is parallel to the walls of the fissures even when these fissures cross the
strike of the schists. This also seems to demonstrate that gneissic lam-
ination is caused by the flow of the rock under differential pressures.
Angular fragments of the Huronian mica schists are included in the
gneiss, the foliation of the latter conforming roughly with the irregular
outlines of the fragments, the flow structure thus produced being always
very marked.

Microscopic Examination of Quartzite and granitoid Gneiss. — There was
obtained from this locality a hand specimen, which, before being sliced,
showed a dark greenish-gray fine-grained quartzite, with two small hands
of.granitoid gneiss irruptive through it. Dr Lawson thus describes it :

"Under the microscope the quartzite is a typical epiclastic rock, presenting no
strong evidence of deformation by pressure. It consists of a heterogeneous aggre-
gate of clastic grains of quartz and feldspar, much of the latter being plagioclase.
I n sections the shape of these grains is rounded, subangular, or sometimes angular.
The larger grains are embedded in a base composed of much smaller mains of the
same materials, but intimately mixed with a green chloritic substance, which gives
its color to the rock. The section crosses the contact of the granite stringer and

WAVY LAKE GNEISS AND QUARTZITE. 321

the quartzite. The contact between the two is sharp, but ragged, and portions of
the clastic rock are seen to have been incorporated in the granite. The granite
itself is'a coarse, angular aggregate of'orthoclase and quartz, with extremely little
of the ferro-magnesian constituent. There is a certain amount of finer base in the
granite, of which it is difficult to say whether it is simply a later and more rapid
consolidation of the magma about the larger constituents or whether it isaportion
of the clastic rock, which has been incorporated without fusion in the granite.''

Other Localities.

Il'.l VY LAKE.

Direction oj the Contact. — The contact was next seen on the western
shore of Wavy lake about six miles in a direction X. in° E. from the
place where it was examined east of Lake Panache.

Character and Relation of the Gneiss and Quartzite. — In the southern
part of Wavy lake the gneissic foliation has a northeasterly trend, which,
in coining north, gradually curves around to an almost easterly direction.
In the northern portion of the lake the strike bends around very abruptly
from a northeast to a southeast direction, and the change is further con-
tinued till in the eastern part of the lake the lamination of these two
areas of gneiss converges in a common strike of N. 70° E. A funnel-
shaped trough is thus formed in the western part of the lake, which is
occupied by a tongue of highly inclined Huronian quartzites. At the
southern edge of this trough the quartzites abut on the gneiss as on an
irrnptive mass, the strike of the former being X. 65° W. ; dip, S. 25° \Y.
<50°, while the foliation of the gneiss is X. E. ; dip, S. E. <75°. At
the northern edge of the trough the stratification of the quartzites cor-
responds in direction with the lamination of the gneiss. Both rocks
strike S. 38° E., although their declination is in opposite directions; the
quartzites dipping S. 52° W. <80°, while the gneiss dips X. 52° E. <8()°.
The quartzites near the line of junction on Wavy lake are not so highly
altered as on Lake Panache, yet the proportion of mica in these rocks is
seen to increase as the gneiss is approached.

Microscopic Examination of tin Gneiss. — Dr Lawson thus speaks of a
thin slice of this gneiss which was examined by him :

"A reddish, highly feldspathic granite, with occasional shear planes traversing it.
Under the microscope the rock is a. granular aggregate of orthoclase, quart/,,
plagioclase and biotite, in which crush phenomena are to a limited extent appar-
ent. The orthoclase is very much kaolinized in its central portion, but quite fresh
in the peripheral zone. The plagioclase is, as a rule, fresh. The biotite is very
sparingly represented and is almost entirely altered to chlorite. There is present
also a little iron oxide. The effect of secondary pressure is seen in the occasional
dislocation of the plagioclase and in cataclastic structure which has, to a limited
extent, been developed in portions of the section."

XLVIII— Hum,. Geoi,. Soc. Am., Vol. I L892.

322 A. E. BARLOW — LAURENTIAN AND HURONIAN ROCKS.

Cleavage Planes and embedded Quartette. — Where the quartzites abui
on the gneiss on Wavy lake a set of cleavage planes is developed parallel
to the line of contact. At the eastern end of the lake, where the folia-
tion of the northern and southern areas of gneiss converge in a common
strike, angular fragments of various sizes of the Huronian micaceous
quartzites were noticed embedded in the gneiss, the foliation of the latter
Bowing around the irregular outline of these fragments.

CHIEFS LAKE.

The Contact. — From Wavy lake the line of demarkation curves around
very quickly from northwest to northeast, and was next ^t'en on the
north shore of Chiefs lake, on the south line of the township of Broder
(Salter's baseline), three ami a half miles east of Long lake. Throughoul
this distance of nearly six miles the general strike is northeast.

The Rocks. — The late Mr Alexander Murray, who made an examination
of the rocks exposed on Salter's base line, simply describes the boundary
here as a junction between " red gneiss " and "greenish mica slate."

BRODER TOWNSHIP.

Direction and Extent of the Contact. — The line from this point strikes
due north into the township of Broder for about a mile, when it bends
around to the northeast for half a mile, and then to X. 78° E.. winch
general strike it maintains till the eastern line of Broder is readied-
Where this last abrupt change in the line of junction takes place the
Huronian rocks, with a strike of X. 75° E. and dip S. 15° E., abut on the
gneiss, whose lamination has a direction of N. 40° E. and dip S. 50° E.
<^68°. Throughout the remaining part of the township of Broder, how-
ever, the micaceous slates and quartzites have approximately the same
strike and dip as the gneiss. The gneiss is always superimposed on the
sedimentary strata and both rocks dip in a southerly direction at angles
varying from 65° to 70°.

Microscopic Examination of Huronian Schist. — A specimen af the Hu-
ronian schist was obtained on tin1 line between lots 4 and •">. concession
HI, three hundred and fifty yards north of the contact with the gneiss.
Dr Lawson says of this ;

•'A gray, moderately fine-textured schist, spotted with scales of brown mica and
having uneven or lumpy cleavage surfaces with marked silvery l:1"ss. Under
the microscope the clastic character of the nick is apparent, it being composed of
grains of quartz and feldspar chiefly. Throughout this clastic aggregate there
have been developed numerous pluies of brown mica and some of muscovite,
nearly all in parallel position. Scattered thoughout theslideare nests of separated
or closely aggregated grains of a light-yellow pleochroic mineral, probably epidote.

CHARACTER OF ROCKS NEAR CONTACT. 323

The separate grains of epidote in each nest have for the most part all a common
orientation and extinguish together. None present crystallographic boundaries

nor distinct cleavages."

Microscopic Examination of the Gneiss. — A specimen of the gneiss ob-
tained from the contact on the line between lots 4 and 5, concession III,
showed its contact with the Huronian schist. Of this Dr Lawson says :

"A pinkish to yellowish gray medium-textured biotite granitoid gneiss, with a
portion of very fine-textured greenish gray schist partly adhering to and partly
enclosed in the granite on one side of the specimen. The thin section examined
is across the contact of the granite gneiss and the schist. In the section the two
rocks are very distinct, and the contact, while fairly sharp, shows portions of the
schists included within the granite. The granite is a granular aggregate of ortho-
clase, microcline, plagioclase, quartz, biotite and muscovite. * * In the struc-

ture of the rock there are some slight evidences of pressure seen in the occasional
dislocation of a crystal of plagioclase, but there is neither shearing nor cataclastic
structure. The schist in contact with this granite is profoundly sheared, and it
only requires an inspection of the slide to see that the shearing was effected before
the magma from which the granite has crystallized was brought in contact with
the schist. The schist is composed essentially of quartz and muscovite, and these
minerals are arranged in parallel thinly lenticular areas which wedge into one
another. The optical tension of the quartz lenses is very constant. The cataclastic
structure of the quartz is pronounced. The general aspect of the schist is that of
a streaky rhyolite."

( 'haracter of the Rocks near the Liar if Contact. — Near the line of junc-
tion the silicious slates and quartzites become highly schistose and show
signs of having been subjected to great pressure. Angular pieces of the
schistose rocks are included in the gneiss, especially near the curve in
the line of junction, while intrusions of gneiss were seen at several places
penetrating the stratified rocks. In one instance a lenticular mass of
distinctly foliated micaceous gneiss was seen intruded through the schists
parallel to their bedding at a distance id' three hundred yards from the
line of contact. Besides these gneissic intrusions there are irregularly
shaped fissures running transversely to the strike of the schists and filled
with coarsely crystalline feldspar and quartz. In the larger portions of
these veins the feldspar and quartz are present in about equal propor-
tion, but where they begin to thin out quartz seems to be the main and
in some cases the only constituent. These pegmatitic apophyses are
evidently portions of the adjacent gneiss which have been injected
through the schists and crystallized in the presence of heated vapors.
A large pegmatite vein of this sort was noticed on the line between
Broder and Dell extending across the strike of the schists for a distance
of half a mile from their contact with the gneiss.

324 A. E. BARLOW — LAURENTIAN AND HURONIAN ROCKS.

DELL TOWNSHIP, DAISY AND BABY LAKES AND LAKE ALICE.

Direction and Extent qftht Contact. — The contact runs in general about
northeast through the township of Dell, striking Daisy lake near the

line between lots 6 and 7. in c session [, of the township of Neelon.

Continuing through Daisy lake to its northeastern end. the line crosses
through Baby lake and the northern end of Lake Alice.

Microscopic Examination of foliated Gneiss. — The Huronian throughout
this distance is represented chiefly by a light yellowish feldspathic
quartzite. As the gneiss is approached this quartzite shows abundant
signs of alteration and disturbance. The immediate contact shows an
intermixture of a dark green chlorite schist, which probably belongs to
the Huronian. and a dark red well-foliated gneiss. Mr W. V. Ferrier.
lithologist to the Canadian Geological Survey, who examined a thin
section of this rock, says:

" Shows an intermixture of a granitic rock with a chlorite schist. In the granitic
portion the quartz and feldspars are broken up into a tine mosaic,, through which
occasional larger grains are distributed. The quartz tills in the interstitial space
between the larger fragments of feldspar. Plagioclase is present, but orthoclase
predominates. A number of curious large crystals occur, too decomposed to admil
of positive identification. The central portion of these crystals is made up of

serpentinous material, and from the form of - s.of them the original material

was probably hornblende. A much-decomposed pyroxene is also present. The
schistose portion of this slide is exceedingly decomposed."

Daisy Lake Rocks. — The northern shore of Daisy lake is occupied by a
reddish feldspathic quartzite interlaminated with some dark, grayish-
green, slaty graywacke. The strike of these is S. •'15° W. : dip, S. 55° E.
<70°-80°. The whole section, as exposed on this shore for a quarter of
a mile to the northwest, show- evidence of the most profound disturb-
ance and alteration. The quartzites, besides being hardened, are pene-
trated by veins of secondary quartz, both parallel to their bedding and
reticulating in all direction-', the whole being much squeezed and con-
torted. At the contact on the south shore both rocks dip southeast
<70°-75°, the quartzite dipping into or under a red granitoid gneiss.
Microscopically, the quartzite is light gray in color, with a Taint flesh-
red tint on weathered surfaces. It seems almost completely vitrified
and presents veins of secondary quartz running parallel with the -t rati-
fication.

Microscopic Examination of th Quartzite. — Mr Ferrier, who examined a
thin slice of this rock under the microscope, says :

"An exceedingly finely laminated quartzite, the lamination being marked by
little strings of muscovite running between the quartz grains. It is evidently a
highly altered da-tic. in which the quartz has almost entirely recrystallized under

ROCKS BETWEEN DAISY AND BABY LAKES. 325

great pressure. It exhibits well-marked parallel structure, its component grains
being drawn out in one direction. The larger drawn out grains show uneven ex-
tinction, as do also the finer-grained ones lying between them. Penetrating this
quartzite were noticed many irregularly shaped intrusions of the coarse granitic
gneiss."

Rocks between Daisy and Baby Lakes. — On the portage from Daisy lake
into Baby lake the rocks strike N. 49° E. and the dip varies from 50° to
70°, but most generally the latter. The beds run in long, sweeping
curves and are penetrated in places by intrusive gneissic material which
shows up well against the darker feldspathic slates and quartzites. The
Huronian rocks are much squeezed and altered. Immediately to the
south of this portage rises a high hill composed of flesh-red granitic
gneiss, the foliation being in general very distinct. Embedded in this
gneiss on the very summit of the hill are patches of a dark greenish-gray,
distinctly bedded, slaty rock, which have been clearly caught up in the
gneiss during its irruption, and which are distinctly referable to some of
the Huronian beds in the vicinity. A specimen illustrating the contact
between these two rocks showed the slaty rock partly adhering to and
)»artly embedded in the granitic gneiss.

Microscopic Examination of Contact Rod-. — A thin section was examined
by Mr Ferrier. who says:

" This section shows a contact between a coarse-grained granitic rock and a chlo-
ritic and epidotic schist. The granitic rock exhibits gneissic structure in the mass
and may be classed as a coarse-grained biotite gneiss in which chlorite now replaces
the original biotite. Intense cataclastic structure is shown, and a curious fact is
that the feldspar,as often observed* under similar circumstances, preserves its crys-
tal form fairly well, whilst the quartz is all twisted and broken. Wulfing has sug-
gested that this may be due to gliding planes [i Jerman gleit Aachen) in the feldspar,
allowing it to yield and be perhaps slightly changed in form but not broken, whilst
the unyielding quartz would be all broken to pieces. The schistose rock presents
no unusual features in its mineral constituents, but has, like the gneiss, been sub-
jected to great pressure. Epidote is very abundant and angular fragments of quartz
and feldspar occur scattered through a very fine-grained chloritic groundmass. The
rock is probably of clastic origin."

A thin section obtained from about the center of the Largest mass was
also submitted to Mr Ferrier, who reports:

"A line-grained amphibolite, consisting of chlorite, epidote, hornblende and a
colorless mineral in the groundmass, which is probably feldspar, although satis-
factory axial figures were not obtained. A little iron with titanite occurs in the

section."

Rocks between Baby and Alice Lakes. — On the portage from baby lake
into Alice lake there is an apparent transition. The gneiss to the south

326 A. E. BARLOW — LAURIfiNTIAN AND HURONIAN ROCKS.

of the portage is a flesh-red, distinctly foliated granitoid gneiss. At the
east end of the portage tins passes upward into a very gneissie quartzite,
whose distinct stratification is in marked contrast to the massive char-
acter of the gneiss. Under the microscope, Mr Ferrier says:

"This rock consists mainly of quartz and feldspar, with a little musruvite and
epidote, and is a beautiful example of a sheared gneiss. It is cut by veins of clial-
cedonic quartz in many cases at right angles to the bedding."

This rock in turn passes upward into the more usual feldspathic quartz-
ite whose elastic origin is undoubted. Both rocks dip S. 35° E. <60°,
the quartzite dipping into or under the gneiss. At a small point on the
eastern shore of Alice lake, just southeast of the portage into Baby lake-
is an exposure of yellowish-gray mica schist, with some dark green horn-
blende schist embedded in the gneiss, which rocks may represent an ex-
treme alteration of the Huronian quartzites and graywackes.

WA UNA PITAL RIVER.

Contact Indicated by Character of the Rocks. — Continuing still further
northeast the boundary strikes the Wahnapital river just below the
Canadian Pacific railway bridge. The actual contact is not seen, but on
the west side of the bridge are light greenish-gray feldspathic quartzites
with some thin interlaminated bands of darker-colored sandy shale, the
whole dipping N. 25° W. <60°-70°. On the opposite bank of the river,
near the railway station, is a dark gray, evenly foliated micaceous gneiss.
dipping S. 23° E. <60°. Ruby-colored garnets are exceedingly numer-
ous, the crystals frequently measuring from a quarter to half an inch in
diameter. The line of demarkation is occupied by the bed of the steam
for a short distance, when it again strikes inland, running parallel to the
general course of the river. At this place the recently constructed rail-
way for the Emery Lumber company nearly coincides with the line ol
junction for a considerable distance, and the contact is seen at several
places close to the road-bed.

The Huronian Representative. — The Huronian exposed at several smal'
cuttings is represented by a dark gray, tinnly-beclded quartzite, rilled
with joints, which cause it to fall to pieces under the hammer, often
rendering it exceedingly difficult to obtain a satisfactory hand specimen.
It is very highly altered, showing almost complete vitrifaction, often
breaks with a conchoidal fracture, and is very similar to that described
as occurring near the contact on Daisy lake. Further to the northeast
the contact has only been examined at certain points, but it has been
thought advisable to postpone any further description in this direction
till it has been worked up in more detail. The foregoing description

00"7

TWO ISLANDS NEAR THESSALON. 32

has only covered the southeastern boundary, and it may be well to define
the junction at a few other points.

#

ROCKS OF THE CONTACT BETWEEN CARTIER AND STRAIGHT LAKE STATIONS.

Between Cartier and Straight Lake stations, on the Canadian Pacific
railway, there is an irregular patch or outlier of Huronian completely

enclosed by gneiss and granite. The junction between the two rocks is
seen just beyond Straight Lake station. The gneiss is very massive,
coarsely crystalline, and very distinctly foliated, while the Huronian is
represented by dark greenish-gray feldspathic shale and sandstone.
The foliation of the gneiss in general corresponds with the strike of the
shale, which is S. M° E., dip S. 6° W. <55°. The sandstone and shale
are altered into very glossy mica schist near the junction, become con-
torted and exhibit interlaminated nodose lines of quartz, veinlike in
origin. These lenses of quartz are clearly secondary and in every case
cause a bulging of the enclosing rock by their introduction, and have
doubtless been formed by the silica set free in the genesis of the gneiss.
Feldspathic intrusions are commonly met with in the sandstone and
shale a considerable distance from the line of junction, while patches of
the sedimentary strata have been caught up in the mass of the gneiss.
Epidote is abundant, especially near the junction.

TWO ISLANDS NEAR TIIESSALO.X.

Contact previously described by Others. — During the early part of October
last an examination was made of the contact as exposed on two islands
close to the north shore of Lake 1 [uron, about five miles east of Thessalon.
As the water was rather high, only a few feet of the junction was exposed
in each instance. The contact here was first described by Irving* in
1887 and later, in 1892, by Messrs Pumpelly and Van Hise.j but as the
author's conclusions differ somewhat from those expressed by the above-
named writers it was thought advisable to bring them forward at this
time.

Difference in the Conclusions <>f the Author and other Writers recited. — The
Laurentian or basement complex, as it has been called, is here repre-
sented by a granite gneiss through which has been intruded large masses
and dikes of a dark greenish-gray, fine-grained diabase. This appears to
be in turn cut by a flesh-red granite, although the frequent absence of

'Am. Jour, of Science, vol. xxxiv, pp. 207-216.
flbid., vol. xliii, pp. 224-232.

328 A. E. BARLOW — LAURENTIAN AND HURONIAN ROCKS.

any sharp line of division between the two rocks would suggesl the
probability that both belonged to the same period of irruption, the more
rapidly cooling diabase being intruded by the more slowly cooling
granite mass. The diabase (according to .Air Ferrier) shows evidence
under the microscope of having been subjected to great pressure, doubt-
less produced before the cooling of the granite magma, while the granite
is comparatively free from any such evidence. The gneiss and granite
contain numerous sharply outlined fragments of a dark-gray schistose
rock which Pumpelly and Van Hise stated I classed as Huronian,
whereas, in their opinion, these' were pre-Huronian. From their article
one would infer that there existed at this locality a. large mass of these
schists from which the smaller fragments had become detached, but
beyond a mass of diabase such as described above and of which they
make no mention, there seems to be no rock-mass from which these
fragments could have been derived. These schists, however, do not in
the least resemble the micaceous schists and quartzites described by me
in contact with the Laurentian through the Sudbury district, for the
former shows no trace whatever of clastic structure, while the fragmental
origin of the Sudbury schists may readily be seen in the field or in a
thin slice under the microscope. The banded appearance of the Thes-
salon schists points to a possibility of an original fragmental condition,
but such must remain merely hypothetical, on account of their extreme
alteration. The late Mr Alexander Murray, on his manuscript map of
this district, frequently alludes to this granitic mass as " red and green
trap " or (i syenite." and both he and Sir William Logan * were of opinion
that the granite was later than tin1 Huronian strata with which it comes
in contact.

The Huronian is represented by what Pumpelly and Van Hise char-
acterize as a "great basal conglomerate," the detritus from which it was
formed resulting from the disintegration of the gneiss and granite. As
close an examination as possible was made of the line of junction, but
the length of contact exposed is far too small to come to any undeniable
conclusion. The very frequent angular or subangular outline of the in-
cluded fragments in this rock point out the probability that the so-called
conglomerate is in reality a volcanic agglomerate or breccia, whose frag-
ments, thrown down in water, have become more or less rounded and
mixed with finer arenaceous material. Besides, the conditions of con-
tact on the two islands are essentially different. On one island the
junction is so sharp and distinct that the line of division can be placed
to the fraction of an inch. However, its abrupt change in strike ("at

*Geol. Canada, 1863, p. 58.

CONCLUSIONS OF AUTHOR AND OTHER WRITERS DIFFER. 320

one place varying within a foot or two as much a.s 4.">° or 50° ") seemed
to me to indicate the irregular outline of an eruptive mass rather than
the sinuous outcrop resulting from prior erosion. On the other island,
only a very short distance away, there is an apparent transition from
the granite to the conglomerate. The conglomerate is very massive, so
that the strike and dip could not he ascertained with any degree of cer-
tainty, and near the line of contact shows abundant signs of alteration.
The contact between this granitic mass and the Huronian was also ex-
amined by the late Mr Alexander Murray at the southeastern end of
Lake Pakowagaming. On a manuscript ma}) to which I lately had
access Mr Murray states that near the junction the Huronian is com-
posed of a red-colored altered quartzite, slate and conglomerate, dipping
north or away from the granitic mass at an angle of 80°. To the south
and in immediate juxtaposition with the granitoid gneiss "the slates are
corrugated and contain patches of red feldspar." A little to the north-
west "'the wrinkled and contorted quartzite and slate are cut by granite
veins, mica and epidote." The rocks on the southwest side of this lake
have all a high inclination northward, while on the northeast side the
slates and quartzite are nearly if not quite flat.

Dr Selwyn lias frequently pointed out, both in personal conversation
and elsewhere, that the Hnronian must be regarded as preeminently a
pyroclastic series of rocks, and if this fact is borne in mind the occur-
rence of most of the so-called conglomerates will he more susceptible of
explanation. These occur at various horizons through the series, and
very frequently intimately associated with the massive diabases. They
seldom, if ever, contain pebbles of gneiss, and the most abundant frag-
ments seem to be of coarse red or gray syenitic granite. As agglomerates
or breccias, some of whose fragments have become rounded by the action
of water, they neither represent a want of conformity nor a great lapse
of time, and simply occur as additional proofs of the intense volcanic
activity which must have characterized this epoch.

The line of demarkation is very seldom a simple plane of division, the
breccia present along the junction frequently covering a considerable
space. It is therefore often impossible to draw an accurate line of divis-
ion between these two rocks unless we assume that such a line should
he placed where the two rocks are present in about equal proportion.
The general correspondence of the gneissic intrusions with the stratifica-
tion of the enclosing schists and the frequent lenticular outline and par-
allel disposition of the detached schistose fragments in the gneiss often
resemble at first sight an alternating sequence of transitional beds.
Again, the crystalline condition of the Huronian feldspathic and mica-

XLIX— Bum.. Geot,. Soc. Am., Vol. 4, 1892.

330 A. E. BARLOW — LAURENTIAN AND HURONIAN ROCKS.

ceous quartzites near the line of contact, which frequently resemble in
character and composition the more evenly laminated gneisses, has been
referred to as evidence of such a transition ; but even in such a case the
bedded character of the Huronian is in strongly marked contrast to the
granitic aspect of the gneiss.

Conclusions and Facts supporting Them.

In conclusion, then, the following facts seem to prove beyond a doubt
the irruptive nature of this Laurentian gneiss and its magmatic condition
at a time subsequent to the petrifaction of the Huronian sediments :

1. The diverse stratigraphic relations of the two rocks along their
line of junction. Most frequently the Huronian strata dip into or under
the gneiss, although often this position is reversed and the Huronian
beds are seen superimposed on the gneiss with perfect conformity. In
many instances the two rocks occupy vertical positions side by side and
occasionally the gneiss has been seen dipping away from vertical Huro-
nian strata. Huronian rocks have also been seen resting unconformably
on the upturned edges of Laurentian gneiss. Sometimes, where the sin-
uosities of the line of outcrop of the gueiss were too abrupt to be followed
by the stratified Huronian. the latter rocks have abutted on the gneiss
as on an irruptive mass. These different phenomena can all be readily
and naturally explained by the irruption of the gneiss, while on the
hypothesis of an aqueous origin such explanation must be difficult and
unsatisfactory.

2. The alteration of the sedimentary rocks along the line of junction
is a feature that has been invariably noticed where the contact has been
examined.

3. The inclusion of angular fragments in the mass of the gneiss which
are clearly referable to the adjacent sedimentary strata. Near the line
of junction these detached pieces have a clear and sharp outline, while
further in the mass, where the}' have undergone partial fusion and ab-
sorption, their outlines are blurred and indistinct.

4. The occurrence of gneissic intrusions as well as more coarsely crys-
talline apophyses of pegmatite both interlaminated with and transverse
to the bedding of the Huronian rocks. These intrusions are distinctly
irruptive and can often be directly traced to their source in the larger
area of gneiss in the vicinity.

5 The absence of limestones, slates or quartzites or, in fact, any species
of rock indicative of ordinary sedimentation for the quartzites and mica
schists sometimes seen interlaminated with the gneiss are simply
quartzose and micaceous phases of the more common feldspathic gneiss.

CONCLUSIONS AND FACTS SUPPORTING THEM. 331

6. The general character of the rock itself, which in appearance and
behavior lias far more resemblance to an ordinary eruptive granite with
a foliated texture than an altered sedimentary rock. Sir ,\V. E. Logan
himself, in his notes of its occurrence on Lake Temiscaming, invariably
refers to it as " gneissoid syenite," and the later Walter McOuat, of this
survey, although he describes in his printed report an intrusive mass of
syenite cropping out on Round lake at the head of Blanche river (north
of Lake Temiscaming), yet on his accompanying manuscript map colors
it as Laurentian gneiss, evidently deeming it of similar character and
origin.

Everywhere this Laurentian gneiss is thoroughly crystalline and pre-
sents no structure that in any way suggests an alteration of clastic con-
stituents. In many places the gneiss can be traced into obscure or non-
foliated areas which present the ordinary characters of true irruptive
masses. The boundaries of these patches are very often illy defined and
they pass insensibly into the ordinary gneiss. The frequent occurrence
of dikes and masses points out a sequence of irruptions whose order it is
often possible to determine over limited areas. The parallel arrange-
ment of the component minerals and the alternation of coarser and finer
bands often suggest the How structure of certain eruptive rocks. The
gneiss usually shows only slight evidences of secondary pressure, seen in
the occasional dislocation of the feldspar crystals, in shearing and in
cataclastic structure which has sometimes been developed. The Huro-
nian schists, on the other hand, present abundant evidence of secondary
pressure in the development of pronounced cataclastic structure, the
presence of numerous shear planes, and the squeezed or drawn-out char-
acter of the quartz grains. Mr Ferrier, however, in his examination of
two thin sections of the granitic gneiss to the south of Daisy lake, discov-
ered the presence of most intense cataclastic structure, which must have
been induced in the rock subsequent to its cooling, but as the schist in
contact with the gneiss also exhibited this extreme phase of cataclastic
structure, and as the stratified rocks in the immediate vicinity are so
highly altered as to preserve hardly a trace of their original clastic struct-
ure, we may, perhaps, safely assume that both gneiss and schist have
been subjected to this same immense pressure at a time subsequent to
their coming together in their present position.

The Huronian system, therefore, may be regarded as the oldest series
of sedimentary strata of which we have at present any knowledge in this
region. The original sediments must have been laid down on a firm
floor, whose composition, judging by the character of the Huronian rocks,
must have been closely analogous to granite. It was doubtless the
fusion and subsequent recrystallization of this granitic floor that gave

332 A. E. BARLOW — LAURENTIAX AND HURONIAN ROCKS.

rise to the Laurentian gneiss. The immense pressure exerted by the
weight of the superincumbent mass of Huronian strata and the crum-
pling, folding and fracturing of the comparatively thin and weak crust
would all tend to sink the lower portions of the Huronian beneath the
line of fusion, the submergence of which would produce conditions of
contact such as have been described and which subsequent upheaval
and denudation have exposed.

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA
Vol. 4, pp. 333-348 August 4, 1893

THE ARCHEAN ROCKS WEST OF LAKE SUPERIOR*

BY WILLIAM HENRY CHATTERTON SMITH

(Read before the Society December 30, 1892)

CONTENTS

Page

The Nomenclature adopted 334

The Region studied 334

Its Boundaries 334

Geologically complex 334

Its topographic Character ' 334

Present Status of the Investigations 335

Distribution and Relation of the Rocks 335

Two great Divisions and their Extent 335

Lower Archean Series 335

Upper Archean Series 336

Terms Contch idling and Keewatin Series suggested by Dr Lawson 330

Character and field Relations of the Laurentian Rocks 336

Relation of Contchiching and Keewatin Series to Laurentian Granites. . . 337

Contact Phenomena Criterion of Relative Age 337

Character of the Contact 338

Origin of the Laurentian Rocks 338

Laurentian Rocks the younger 338

Selection of the Term Laurentian based on imperfect Knowledge. . . . 338

Considerations affecting the Status of the Term Laurentian 339

The Contchiching Series 340

Rocks composing it 340

Position and Relation of its Rocks 340

Its Thickness 340

Clastic in Origin 341

Structural Conformity between Contchiching and Keewatin 341

The Contchiching and Keewatin lithologically distinct 341

Conditions under which Contchiching and Keewatin wei'e formed 342

The Keewatin Series 342

Rocks composing it 342

Its stratigraphic Succession 342

The Steep Rock Series 344

Discordant in Character 344

Its Stratigraphy 344

* Published by permission of the Director of the Canadian Geological Survey.
L— Bull. Geol. Soc. Am., Vol. 4, 1892. (333)

334 W. H. C. SMITH — A.RCHEAN ROCKS WEST OF LAKE SUPERIOR.

Pmk<

A folded Syncline 345

Its Thickness 345

Its Relation to the Laurentian and Keen at in 345

Etl'eet n | ion it of orographic Movement 345

Older than 1 he Ani mi kie 345

Its Unconformability not always observable 346

The Unconformity a .Measure of geologic Time 346

Its Relation to the Atie < >ban Series 346

Economic Geology of the Airhean 1)47

Present Knowledge superficial 347

Iron Ores 348

Gold 3 18

Nickeliferous Diorite • .'54 s

The Nomenclature Adopted.

In this paper I shall adopt the nomenclature employed for many years
in the publications of the Canadian Geological Survey without at present
making any attempt to justify it. The term ''Archean." then, will be
used, not in the restricted sense advocated by Geikie* nor in that held
by Van Hise,f but in its broadest application, as embracing all the rocks
stratigraphically inferior to the Animikie rocks of Lake Superior.

The Region Studied.

Its Boundaries. — The portion of the Dominion of Canada to which at-
tention is here drawn may be briefly described as the southern half of
Rainy River district, in the province of Ontario, lying between our trans-
continental highway and the international boundary, and the Lake of
Woods, in the west, to the western boundary of Thunder Bay district.

Geologically complex. — It would lie difficult to imagine a more interest-
ing field or one that offers such facilities for geologic investigation, yet
from the complexity of the structure of the rocks ; from their antiquity ;
the tremendous movements they have suffered, as well as the changes
they have undergone, and from the absence of all fossil remains, there is
perhaps no part of the country about which so many difficulties cluster
or in which lie so many pitfalls for the feet of the unwary, the hasty, or
the dogmatic geologist.

Its topographic character. — Physically, the country presents a vast
network of lakes which with their connecting streams, afford a ready

* Anniversary address before the Geol. Soc. of London on the volcanic rocks of England by
Archibald Geikie, V. R. S., February, L891.
•f-Arn. Jour. Sci., vol. xii, p. 1 17.

DISTRIBUTION AND RELATION OF THE ARCHEAN ROCKS. 335

means of transport by canoes. The lakes vary in size from mere ponds
to great island-dotted sheets of water, of which the largest — the Lake of
the Woods — embraces within its shore lines an area of hardly less than
six thousand square miles. Probably one-fourth of the whole area is
occupied by water. Tbe land surface presents a tumbled and irregular
succession of low, rounded hills, with here and there a sharp ridge or
steep escarpment, but bold and rugged scenery is extremely rare. The
surface has .a gentle average slope from the watersheds to the drainage
basins, and it is doubtful if the top of the highest hill is over seven hun-
dred feet above the bottom of the lowest and deepest lake. This area
occupies the southern margin of the Arctic basin.

Present Status of the Investigations. — A description of tbe distribution of
the various rocks would be tedious and incomprehensible without con-
stant reference to a good map. A large portion of the area is depicted
on maps already published by the Canadian Geological Survey. A re-
port upon and map of part of the remainder have been prepared by the
writer and are now in press, while topographic and geologic materials
relating to still another portion of the remainder have been collected and
are now being prepared for publication. In addition to this, the writer
has made several preliminary reconnoissances and surveys in those por-
tions in which the field-work is incomplete.

Distribution and Relation of the Rocks.

Without entering into the details of rock distribution, there is one im-
portant feature of it which is worthy of attention.

TIFO GREAT DIVISIONS AXD THEIR EXTENT.

Lower Archean Series. — Separating tbe rocks for the present into two
great divisions, (1) the lower granitic and syenitic rocks, more or less
massive, and (2) the upper micaceous, hornblendic and trappean rocks,
for the most part distinctly schistose, we find that the former occupy
large rounded or ovoid areas which sometimes anastomose and the
peripheries of which approach each other to within comparatively narrow
limits. The longest axes of these areas are rudely linear to and parallel
with each other and have a general northeast or east-north direction.
In geographic extent these granitoid 'rocks cover considerably more than
halt of the whole country. It is interesting to note that such nuclear
areas of granite are reported by Barlow north of Lake Huron and are
mapped by Hitchcock in New Hampshire. As we pass from the Lake
of the Woods in an cast-southeast direction obliquely across the granitic
areas we find that they become proportionately narrower and longer in

336 W. H. C. SMITH — AKCHEAN ROCKS WEST OF LAKE SUPERIOR.

an increasing ratio as the shores of Lake Superior are approached. It

would seem as if the Archean rocks alter their consolidation in their
present relations had been crushed together by a tremendous lateral
force emanating from the southeast, the effect of this pressure becoming
less and less as the distance from the supposed center of force increases.
Upper Archean Series. — Surrounding the nuclear ovoid and lenticular
areas of granitic rocks as an irregular hut almost uninterrupted network
and dipping away from them generally on all sides lie the complex and
varied rocks of the upper Archean series. The tendency of the two
great divisions of Archean rocks to assume this relative distribution was
first pointed out to me by Dr A. C. Lawson, and subsequent explorations
in parts of Rainy River district unvisited by him have so far confirmed
his opinion that such a relative distribution would be found to be charac-
teristic of this region.

TERMS C0XTCHIC11I.\<; AND KEEWATIN SERIES SUGGESTED BY DR LAWSON.

The rocks occupying the ellipsoid synclinal troughs between the nuclei
of granite have been separated by Dr Lawson (the classic authority on
this region) into two divisions, for which he suggested the names of
Contchiching for the lower and Keewatin for the upper. He has since
proposed the name Ontarian to include these two groups. For the
underlying granitic rocks the term Laurentian is used.

CHARACTER AND FIELD RELATIONS OF THE LAURENTIAN ROCKS.

The Laurentian rocks of this region are for the most part essentially
granites. A gneissic foliation is often apparent and frequently well
marked, particularly in the peripheral zones of the areas, while the cen-
tral portions are usually more granitoid. The rocks vary in texture
from fine- to coarse-grained and pegmatitic, and in color from light to
dark gray and from pink to deep red. In composition they present
many various characters. Usually the ferromagnesian mineral is biotite
with more or less muscovite. Hornblende granites are not uncommon.
The latter sometimes merge into the biotite granites by a gradual change
in composition, but usually a sharp line of demarkation separates them.
The relations in the field are sometimes suggestive < >f large brecciated frag-
ments of hornblende granite caught up in the biotite granite, and some-
times of intrusions of the former into the latter. The relations of these two
varieties of granite form an interesting problem for future study, hut as
yet the writer is not prepared to formulate any general theory concerning
them; indeed, it is doubtful if any generally applicable theory is possi-
ble, as there is reason to believe that the hornblende granite is sometimes

CHARACTER AND RELATION OF THE LAURENTIAN ROCKS. 337

the younger, sometimes the older and sometimes a contemporaneous rock;
while it is not probable that there is any great difference in their respect-
ive ages. In this connection it is interesting to note that in Finland Dr
J. J. Sedesholm * finds that there are two main series of granites, of which
the earliest plageoclastic and hornblendic are eruptive in their relations
to the Archean schists and younger than them; the other series, red
garnetiferous muscovite microcline granites, the coarser varieties of which
merge into a pegmatite, are the latest eruptive rocks of the Archean com-
plex. On Hunters island there is a considerable development of red
garnetiferous muscovite granite, very coarse-grained in places, the rela-
tions of which are not so clear.

Frequently the granites of Rainy River district are almost devoid of
bisilicate, merging into red felsites and compact, massive gray feldspathic
rocks approaching quartzites, which a well-marked system of cleavage
planes sometimes cuts into regular rhomboidal blocks.

Again the bisilicate is frequently altered to chlorite. The granites
sometimes exhibit a distinct porphyritic structure, evinced by the large
crystals of feldspar in a finer-grained groundmass. These porphyritic
granites have often a distinct gneissic foliation.

For convenience of reference the separate areas of granite in this region
have received distinctive geographic designations in the reports of the
Canadian Geological Survey. One of them, which in the forthcoming-
report on the Seine River district will be named the Seine area, is re-
markable for the predominance of plagioclase in the rocks of its south-
western portion; this, in association with chlorite, which is probably
derived from hornblende, characterizes the rock rather as a quartz-diorite
than a granite. The microscopic examination of the rocks of this area
is not yet complete, but in the field there seems to be a gradual passage
of the quartz diorite or chloritic plagioclase granite into the ordinary
orthoclase granite; certainly the writer has so far been unable to find
anywhere a sharp line between them. Plagioclase in greater or less
proportion occurs in main' of the granites of the whole region.

RELATION OF CONTCHICIIING AND KEEWATIN SERIES TO LAURENTIAN

GRANITES.

Before proceeding to a consideration of the rocks of the Contchiching
and Keewatin series, it would be well to refer briefly to the relations
which the Laurentian granites bear to them.

Contact Phenomena Criterion- of Relative Age. — In the absence of pale-
ontologic evidence the most important criterion that remains for the
determination of the relative age of contiguous rock series arc the features

*The Archaean Eruptive Rocks of Finland, by Dr J. J. Sedesholm.

338 \V. II. ('. SMITH — ARCHEAN ROCKS WEST OF LAKE SUPERIOR.

of the contact between them, as justly observed by Barlow.* These
features have been so clearly and precisely described by Lawson in his
official reports that it is unnecessary to repeal them here; suffice it to
say that 1 have found his description to apply to all the contacts that I
have observed in the portions of Rainy River district nol reported on by
him. While it is true that some of these features, such as the intimate
interbanding of the gneisses or foliated granites and the schists, may be
regarded as analogous to the intimate interbanding frequently observed
in sedimentary strata : and while it is also true that some other features,
such as the angular fragments of one rock embedded in the other may,
where these brecciated zones are narrow, he due to the shattering of the
rocks along a line of fault, still there are many contact features which

cannot be accounted for on any tl -y which holds to the sedimentary

origin of the granite gneisses; such features are the apophyses of granite
which can be traced directly into the main mass, and which sometimes
are parallel to the planes of schistosity of the rocks which they invade
and sometimes cut across these planes. It must not be forgotten that
the phenomena that have been described by Lawson are not isolated
instances of peculiar occurrences extending in the aggregate over but a
small proportion of the contact line, but are typical examples every-
where characteristic of the contact, and the absence of which is rare.

Character of the Contact. — A comprehensive and careful study of the
contact of the Laurentian and Ontarian rocks of Rainy River district
forces us to the conclusion that it is eruptive or irruptive in character.

Origin of the Laurentian Rocks. — Either, then, the so-called Laurentian
rocks of this district have been irrupted in the form of a plastic magma
into the overlying rocks after these had become consolidated (the attrac-
tive theory of Dr Lawson) or else a remarkably continuous series of
later eruptions have been extruded in the planes of contact between
the Laurentian and Ontarian rock, presumably the line of weakness.

Laurentian Roch the younger. — This latter theory is open to so many
and serious objections that it has i'vw adherents. If the former theory
is correct, the granite gneisses, with regard to all the relations of which
we have any certain knowledge, are younger than the rocks which they
invade, and, as they pierce both the Contchiching and Keewatin. their
present condition is of post-Keewatin origin.

Selection of the Term Laurentian based mi imperfect Knowledge. — The
earlier descriptions of the Laurentian rocks of eastern Canada must be
regarded as imperfect, and the contact features have not been described.
They are therein spoken of as metamorphic sediment interior to the

* The Contact of the Laurentian and Hnronian Rocks North of Lake Huron, by A. E. Barlow,
Am. Geologist, vol. vi, no. 1, ]>. L9, Also ante, pp. 313-332.

THE TERM LAURENTIAN. 339

Huronian, and the writer is not aware of any general contradiction that
has been given to the assumption by more recent writers on Quebec and
eastern Ontario. For this reason the application of the term Laurentian
to the irrnptive granite gneisses west of Lake Superior is perhaps un-
fortunate, as involving a hasty and undetermined correlation.

Consideration* affecting the Status of the Term Laurentian. — Admitting
for the moment that the Laurentian rocks of Quebec are of sedimentary
origin, and that the granite gneisses west of Lake Superior are irruptive
in their character, it is still possible, nay, probable, that the two are con-
temporaneous in age and identical in primal origin on the assumption
that these latter rocks but represent metamorphism carried to the ex-
treme of fusion (as a consequence of the relatively higher local elevation
of the isotherms), resulting in their irruption into the overlying Huronian
strata and their recrystallization in the form of consolidated magma.
The question, then, of the most appropriate name for these western
Ontario granites becomes a question of the era of our chronology.

Shall we date them from the time of their intrusion into the overlying
strata, or shall we go further back into their obscure history and date
them from the time when in all probability they formed the solid floor
on winch the Contchiching and Keewatin rocks were laid down ? In
other words, shall we call them Huronian (the term is here used to in-
clude all the rocks between the fundamental granites and the Animikie)
because they are intrusive into Huronian strata, or Lurentian on the
above assumption of their genetic identity with the Laurentian gneisses
of the east? If we can regard the irruptive origin of the present relations
of these granites to the Upper Archean rocks as indubitably established,
it would seem unwise to go behind this fact into the uncertain realm of
theory to justify for them the name " Laurentian," as the term ': Huronian
granite " embodies a more precise statement of our conclusions.

But the passage of the granitic phases into the gneissic is so gradual,
the lithologic similarity between the gneisses of the east and of the west
is so marked, and their geographic continuity so highly probable, if not
an established fact, that it is difficult to conceive of any great genetic dif-
ference or of any considerable geologic interval between their respective
ages. The applicability of the term Laurentian, as applied to the gran-
ites of Rainy River district, is also supported by the fact that as the
Laurentian of Quebec is being reexamined in the light of modern
knowledge, the opinion is gaining ground that at least the "Lower
Laurentian" rocks present characters precisely analogous to these of the
west. Perhaps some of the rocks that have hitherto been called Upper
Laurentian in the east are the equivalents of the Contchiching series of
Lawson, although they differ from them in some lithologic characters.

340 W. II. C. SMITH — A.RCHEAN ROCKS WEST OF LAKE SUPERIOR.

THE CONTCHICHINO SERIES.

Rocks composing it. — The < lontchiching series consists essentially of finc-
grained evenly laminated biotite gneisses, light gray in color : of fine to'
coarsegrained mica schists, generally highly feldspathic and sometimes
very quartzose, from dark gray to light gray in color and brownish or
" rusty " weathering, and of fine-grained hornblendic mica schists.

Position and Relation ofitsRocks. — In the southeastern part of the district
they occupy a position always intermediate between the granite gneisses,
which in the contact zone generally invade them in parallel bands,
apophyses and dikes, and the hornblende schists and altered traps at
the base of the Keewatin, which overlie them in conformable position.
They frequently merge into these by a gradual change in mineral com-
position across the strike. N. H. Winchell * refers to a gradual and con-
formable transition between Vermiline (Contchiching) and Keewatin.

In the Lake of the Woods there is a series of mica schists which,
according to Dr Lawson's descriptions^ are closely similar to those which
he subsequently separated from the Keewatin and designated under the
name of Contchiching. In his hypothetical sections of this district, the
accuracy of which, however, he does not insist upon, he relegates these
mica schists to the highest position in the Keewatin scale. By a refer-
ence to the map, however, it will be seen that in their most important
development they occupy a position on the margin of the Keewatin
trough in the southwestern part of the lake and in direct contact with the
Laurentian granites. While developments of these mica schists are
found in interior portions of this Keewatin trough, such a position may
easily be accounted for on the assumption that they represent the crests
of anticlinal folds exposed by denudation. Indeed, the foldings and
disturbances in this trough have been so great that almost any position
in the scale may be attributed to the mica schists of this complex series.
The inference is strong that these rocks in the Lake of the Woods are
the equivalents of the Contchiching series of Rainy lake.

Its Thickness. — In this latter region Dr Lawson attributes to the Cont-
chiching series;j; a maximum thickness of from 24,000 to nearly 29,000
feet. On a similar interpretation of the structure east of tins, in the
western part of the Hunters Island region, about the same thickness may
lie inferred. The writer, in bis report on this latter region, now in press,
states at some length bis reasons for doubting that these rocks have such

* 17th Ann. K.'p <>t' the Geol and Nat. Hist. Survey of Minnesota.

f Report on the (ieology of the Lake of the Woo Is, by Andrew C. Lawson. Pari C E of the Ann.
Rep. Geol. Surv. of Canada, 1885.

; Report "ii the Geology of the Rainy Lake Region, by Andrew C. Lawson, M. A., Ph. L>.. part E,
Ann. Rep. Geol. Surv. of Canada, L887 '88.

RELATION OF THE CONTCHICHING AND KEEWATIN SERIES. 341

an enormous thickness. Without recapitulating these reasons here, it
will be sufficient to state that in his opinion the Contchiching series
nowhere in the Rainy River district attains a greater thickness than
9,000 feet, the greater apparent thickness being due to multiple
folding.

Clastic in Origin. — -The clastic origin of the gneisses and mica schists of
this series can hardly be doubted by any one familiar with them in the
field; their fine and even lamination and their bedded appearance affords
in itself almost conclusive evidence and the microscopic descriptions of
them by Lawson strongly support this view. Their mineral composition
indicates derivation from the denudation of a granitic floor.

Structural Conformity between Contchiching and Keewatin. — -Between the
Contchiching and the Keewatin rocks there is everywhere a strict con-
formity of structural relations. In rocks which have suffered such great
mechanical deformation, however, it must always be borne in mind that
much of the original structure may have been obliterated and replaced
by subsequent cleavage, so that it is hazardous to state that because
there is now strict parallelism in the existing schistose planes of contig-
uous rock series that this necessarily indicates original conformity. Dr
Lawson argues an interval of erosion between the Contchiching and
Keewatin series from the presence at the base of the Keewatin of a con-
glomerate on the Seine river and on hat Raot bay of Rainy lake. The
former of these conglomerates is for the most part an integral portion of
Hie Keewatin series and for only a small proportion of its development
does it occupy a strictly basal position, so that it rather marks a local
break in the Keewatin itself than one between the Keewatin and Cont-
chiching, serving in a measure rather to bind these series together
than to separate them. The so-called conglomerate of Rat Raot bay is
mapped as lying wholly between the two series, but from what the writer
has seen of it he regards it as rather of volcanic than of detrital origin.

Tlie Contchiching and Keewatin lithologically Distinct. — That the Cont-
chiching series is lithologically distinct from the Keewatin, and marks a
period subsequent to which a profound change in the conditions of rock
formation took place, cannot be denied, and the term is useful and appro-
priate as designating a well-marked and perhaps the most important for-
mation of an extensive series; but the Contchiching cannot be regarded
as in any respect coequal or coextensive with the Keewatin. There is no
stronger evidence of unconformity between the two than there is between
any two distinct horizons of the Keewatin, particularly where conglom-
erates are developed, and the Contchiching would seem to be therefore
essentially the basal portion of the Keewatin.

LI-Bur,r,. Gkoi-. Soc. Am., Vol. 4, L892.

342 W. II. C. SMITH— rAECHEAN HOCKS WEST OF LAKE SUPERIOR.
CONDITIONS UNDER WHICH CONTCHICHINQ AND KEEWATIN WERE FORMED.

The close of the period during which the Contchiching rocks were laid
down ushered in an era of intense and long-continued volcanic activity.
interrupted perhaps and succeeded by periods of compensative quies-
cence during which erosion and sedimentation took place; but during
Keewatin times no certain evidence of any great or extensive crustal
movements is afforded. The whole Keewatin and Contchiching series
seems to have been folded by one great and perhaps simultaneous up-
heaval of the original floor. This folding marked the close of the
Keewatin epoch. Barlow* suggests that the concentric lamination in
the ovoid areas of granite gneiss indicates that the forces of upheaval
acted from certain centers ; this may he so, hut the phenomenon may
also be accounted for by the flow of the magma being directed by its
proximity to the hard schists, it may be more correct to say that the
folding of the schists was caused not so much by an upheaval of the sub-
crustal magma acting from centers of force as by the crumpling, due to
lateral compression, forcing their synclinal folds into the plastic magma.

THE KEEWATIN SERIES.

Rocks composing it. — The Keewatin series consists for the most part of
plutonic, volcanic and pyroclastic rocks. While some of the upper
members seem to be more or less altered aqueous sediments, the propor-
tion of Undoubtedly clastic rocks is small.

Its stratigraphic Succession. — Unfortunately the microscopic study of
these rocks is as yet incomplete. The solution of their stratigraphic suc-
cession is confronted by almost insurmountable difficulties, and only a
general suggestion as to the sequence of broad and ill-defined groups can
be offered. The line of demarkation between the numerous horizons is
seldom clear, and where those horizons can be separated at all they are
not always found to occupy the same relative position. They are seldom
very persistent, and overlap each other as more or less attenuated lenticu-
lar hands. I know of no place in this district presenting a complete sec-
tion of the Keewatin. The most important and complete development
of this series is found in the Lake of the Woods and Rainy Lake regions.

Speaking generally, then, the basal members of this great series con-
sist of dark green or black crystalline hornblende schists, generally fine-
grained, and which are sometimes seen to merge into the mica schists of
the Contchiching : of dark and light green altered traps, generally mas-
sive, hut sheared and broken by pressure and sometimes rendered
schistose; of green chlorite schists, which sometimes seem to be altered
hornblende schists and often again are almost undoubtedly hut highly

* Am. i reologist, vol. n i. qo, 9, July, 1890.

THE KEEWATIN SKRIKS. ."> I.'I

schistose phases of the altered traps. At the top of the series are found
soft, fissile, light-gray schists, micaceous schists and some altered clay
slates. Between the rocks which may he always recognized as the hasal
rocks ami those which appear to be always in the highest position in the
scale are a complex group of volcanic detritals, agglomerates, tuffs and
trap, ashes, felsite schists, sericite schists and fine-grained evenly schistose
quartz porphyries. Some of these rocks were probably thrown out as
volcanic ejectamenta and, falling in the waters of ancient lakes, were sifted
and stratified by their restless motion. In this way perhaps some of the
conglomerates have been formed. < )thers again are probably but volcanic
breccias, of which the harder fragments have been more or less rounded
in their passage through the vents and in subsequent movements before
they became consolidated in the matrix. On the Seine river the chlorite
schists in one locality contain abundant lenticules of quartz which are
often ver}r wide in proportion to their length, giving the rock a con-
glomeratic aspect. These again are sometimes lengthened out and appear
as irregular lenticular quartz stringers. While some of the Keewatin
conglomerates have the appearance of being true sedimentary depositions
on old beaches, there is yet a degree of uncertainty as to their character
and origin. These are lor the most part local in extent and narrow in
development and occur at various horizons in tin; middle and lower por-
tions of the Keewatin. They may, as Sir Archibald Geikie* says, " un-
doubtedly indicate Local disturbance connected perhaps with terrestrial
readjustments consequent upon the waning of volcanic energy;" but it
is extremely doubtful if in this part of the country they mark a great or
continuous break dividing the Keewatin rocks into a lower and upper
division at any recognizable horizon. Their significance seems to be
merely local. Professor Van Bisef attaches importance to several de-
scribed occurrences of conglomerates. In only one case, however, was an
undoubted unconformity observed below the conglomerate, and this may
be accounted for by the assumption of a fault. The collective extent of
all the conglomerates described by these authors is insignificant in com-
parison with the area, to which they would apply their conclusions. The
absence of unconformity of structure between the conglomerates and
underlying rocks, which is likewise, so far as observed, in the Canadian
area northwest of Lake Superior an invariable rule, is in itself a signifi-
cant fact, for the same cleavage-producing forces which might entirely
obliterate all original structure in the fine-grained schists would not

♦Anniversary address before the Geological Society of London on "The volcanic Hoiks of Eng-
land." 1891.

t " An Attempt to harmoniz : some apparently conflicting Views of Lake Superior Stratigraphy,''
Am. Jour. Sci., vol. Ixi, p. 117, and "Observations on the structural Relations of the Upper Ilnro-

nian, Lower Huron ian and Base at Complex on the north Shore of Lake Union," Am. .lour. Sci.,

vol. lx iii, p. 224. This latter paper was prepared in collaboration with Mr Pumpelly.

3 I I W. It. C SMITH — ARCHEAN ROCKS WEST OF LAKE SUPERIOR.

obliterate all traces of the original bedding planes in these coarse elastics.
In so far, therefore, as the conclusions of Van Hise and Purnpelly are
applied to the Lower Archean rocks of Canada northwesl of Lake Superior,
the writer regrets that he finds himself al variance with these eminent
authors, being a follower of Geikie in the belief that conglomerates do
not necessarily mark any stratigraphic discordance in these old rocks.
These conglomerates have not yet received the attention which they
deserve, and we may hope that a more detailed an 1 extensive study of
them will elucidate some of the problems of Archean geology.

THE STEEP ROCK SERIES.

Discordant in Character. — The Laurentian and Ontarian rocks hitherto
considered do not embrace all the presumably Archean rocks found in
this country. Mr Smyth, late of the United States Geological Survey.
recognized and described* a discordant series, which is almost undoubt-
edly of post-Keewatin age, about the shores of Steep Rock lake.

Its Stratigraphy. — This Steep Rock series consists of the following hori-
zons in ascending order:

I. Basal quartz conglomerate, sometimes represented by a massive
quartzite, estimated to be 430 feet thick.

II. Lower limestone, dark and light bluish-gray, with the bedding
marked by clierty seams, weathering in relief. The upper part of this
formation is a characteristic breccia of limestone and trap fragments in a
matrix of consolidated calcareous floor; thickness, 500 to 700 feet.

III. About 600 feet of a very soft, fissile, dull green, pyritiferous, vol-
canic ash, containing beds of jasper and iron ore.

IV. Interbedded, coarsely crystalline, greenish-gray traps (probably
diorite), with layers of dynamic green schists ; thickness, about 1,000 feet.

V. Upper calcareous green schist, with thin seams of limestone. 600
feet thick.

VI. Upper conglomerate, varying from hydromica schist, with many
grains of quartz, to a rather coarse conglomerate. The inclosed pebbles
consist entirely of quartz and granite; maximum thickness, 100 feet.

VI L. About 1,400 feet of light greenish-gray, close-tectured, massive
greenstone and greenstone schist.

VIII. Agglomerate, 300 fee< thick.

IX. Dark gray clay slate, of unknown thickness. Higher horizons
probably occupy the country to the south of the lake.

Such are briefly the descriptions of horizons by Smyth in his admirable
memoir. The work since done by the writer in connection with the
rocks of this series suggests no important modification of them.

♦ "Structural Geology ol Ste< p R >c1j Lake, ' >ntario," Am. .lour. Sei., vol. xlii, p. 317.

THE STEEP ROCK SERIES. 345

A folded Syncline. — The discovery of a well-marked band of brownish
gray clay slates very similar to those on the shore of Steep Rock lake,
striking in an easterly direction and dipping to the north, though at high
angles, which lie about a mile and three-quarters south of the southern
bend of the lake, and which would seem to represent the southern upfold
of the horizon (IX), would indicate that the series must he regarded
rather as a folded and buckled syncline than as a tilted and buckled
monocline. This simplifies the conception, as it answers the somewhat
troublesome question as to what has become of the corresponding half
inferred by the supposed monocline. The country south of the middle
bend of Steep Rock lake and lying between its western and eastern long-
extending arms is extremely rugged and is almost impassable, so that
the sequence of the rocks could not be worked out.

Its Thickness. — If the conclusions drawn from the discovery of the clay
slates south of the lake are just, the higher horizons inferred by Smyth
seem to consist principally of coarsely crystalline traps and light greenish-
gray, close-textured traps, with their schistose mechanical derivatives
paralleled by horizons IV and VII. and about 4,000 feet must he added
to the total thickness of the series as estimated by Mr Smyth.

Its Relation to the Laurentian and Keewatin. — This extensive series ap-
pears to have been laid down upon the eroded surface of the Laurentian
and Keewatin rocks long after the irruption of the Laurentian granites.

Effect upon it of orographic Movement. — It appears, then, as pointed out
by Smyth, to have been folded by crustal movements into a cynclinal
trough, whose axis had a northwest and southeast direction. Subsequent
to this ;i great lateral pressure, acting in a direction nearly parallel with
this synclinal axis, has buckled the whole series in a horizontal plane
and crushed and sheared the underlying basement rocks. Relief from
this pressure was also afforded by a slipping of the rocks in the vicinit}'
of Northwest bay of Steep Rock lake, indicated by a complicated series
of faults which are clearly recognizable in the Steep Rock series and may
be inferred by the distribution of the Laurentian and Keewatin rocks to
the north and to the south. These faults indicate a horizontal disloca-
tion of nearly 7,000 feet in the aggregate, and that the vertical dislocation
must have been of even greater extent is inferred by the volume of these
newer rocks which were faulted below the present level of denudation.

Older than the Animikie. — The lateral pressure which produced these
faults and the remarkable structure of the Steep Rock series acted in a
northwest and southeast direction, and it is most highly probable that
it was the same pressure which, acting from a center of force to the south-
east, produced the lenticular character of the granitic areas referred to in
an earlier part of this paper. As the Animikie rocks northwest of Lake

346 W. H. C. SMITH — ARCHEAN rocks west of lake superior.

Superior exhibit no trace of this or of any Lateral pressure, the inference
is stronu that the Steep Rock series is older than the Animikie.

Its Unconformability not- always Observable. — The unconformity between
theSteep Rock series and the Lanrentian dioritic granites and anticlastic
chloritic schists of the north and east shore of Steep Rock lake admits of
scarcely any doubt, but the unconformity above the Keewatin schists of
the Seine river to the southwest is not at all obvious. Lithologically the
green altered traps and schists of the two series are strikingly similar
and could not probably he separated by the most careful study, hut it is
significant that west of the faults of Steep Rock lake the most careful
search on the part of both Mr Smyth and myself lias been rewarded, as
far as I know, by the discovery of only one exposure (and that of a few
square yards in extent) of rock that can with any degree of certainty he
regarded as representing the characteristic limestone formation of the
Steep Rock series. This was found by the writer on the north side of
Seine river, about four miles west of the mouth of the Atic Oban river.
Farther down the Seine river some thin bands, which are very doubt-
fully representatives of the upper calcareous formation (VI), are seen in
two or three localities, but these are of trifling extent. West of Steep
Rock lake and north of Seine river are some important developments of
traps, light greenish-gray and fine-grained, with some dynamic schists,
probably derived from them, which are microscopically quite similar to
those grouped under horizon VII. We would expect, however, to find the
remains of the eruptive members of this series among the lower rocks of
the neighborhood. It seems, therefore, that to the west the Steep Rock
series has been faulted up and swept away, and whatever significance
may attach to discordance of present structural relations on opposite
sides of a fault plane, these relations point to the conclusion that this
series lay unconformably on the Keewatin.

The Unconformity *> }[r<i*irr< of geologic Time. — If the above interpreta-
tion of the structure and relations of this series is correct, it is most in-
teresting, as it is the most important if not the first recognized undoubted
unconformity in the Huronian system of the Canadian geologists. As
the period of time predicted by this series is enormous, it strongly
emphasizes Lawson's statement thai the erosion interval between the
Keewatin and the Animikie is the greatest in American geology.

Its Relation to the Atic Oban Series. — To the south the Steep Pock series
appear to have been removed by the same causes. South of the south-
west arm of Steep Pock lake it appears to be cut off by the quartz por-
phyries of Smyth's tentative Atic Oban series, but the writer's sub-
sequent examinations have convinced him that the sonthwestward
extension of these quartz porphyries is not great and almost certainly

ECONOMIC GEOLOGY OF THE ARCHEAN. 347

does not reach to the probable southern extension of the great fault in
the western part of Steep Hock lake. These quartz porphyries become
distinctly finer grained in the vicinity of the Steep Rock series to the
northwest anoVwest and less certainly so as the massive altered traps to
the south are approached. They are extremely massive and coarse-
grained in the intermediate portions. The altered traps to the south,
the writer thinks, belong to the Keewatin, being succeeded in descending
order by chloritic, hornblendic and micaceous schists and Laurentian
granites. The quartz porphyries appear to be a unit mass erupted, since
the deposition of the Steep Rock series, along a probable fault plane or
line of contact between the underlying Laurentian and Keewatin rocks,
presumably the line of weakness. They extend several miles to the east,
north of and rudely parallel to the general direction of the Atic Oban
river, and send out long apophyses northeast into the Seine granite area.
Their contact with the " greenst* me " to the south seems to be less irregular.

The introduction into the already confused Archean nomenclature of
the unnecessary term "Atic Oban series " is to be deprecated, as it can
only include this unit mass of eruptive rock, the correlation of which
with other similar masses must always be uncertain.

Whether the eruption of these quartz porphyries preceded or suc-
ceeded the great oratechnic movement which buckled the Steep Rock
series must remain as yet an open question. Their massive character
on Margaret lake favors tin; view that they are of later date than this
movement. On the other hand, they are here found in their broadest
development, and their mass and perhaps a superior hardness may
have enabled them to resist this pressure. In the terminations of the
apophyses which they send into the Seine area of granites the rocks are
found to be intensely crushed ; and if the isolated bands of crushed and
sheared quartz porphyries which are found in the Seine area northeast
of Steep Rock lake are of the same age, they must have antedated this
lateral pressure.

Economic Geology of the Arciiean.

Present Knowledge superficial. — Our knowledge of the economic geology
of the Archean rocks is purely superficial, as no real mining has been
done and no facilities are thus afforded for an exhaustive study of the
ores and their intimate relations. The writer cannot refrain from ex-
pressing his opinion here that the laws of Ontario are primarily to blame
for this stagnation in mining. As they encourage every evil tendency of
mining speculation and discourage every attempt at scientific exploita-
tion and healthy development, the mineral wealth of this undeveloped
country remains unimproved and unremunerative.

348 W. II. C SMITH — AUCIIKW ROCKS WEST OF I.Ak'K SUPERIOR.

Tron Ores, [ron ores, in many places known to be rich and in others
reasonably presumed to be so, below the surface arc more or less abun-
dant in three distinct horizons. During the Last two seasons the writer
has discovered magnetic ores, free from sulphur, phosphorous and titanic
acid, in micaceous schist. probaMy of Contchiching age. These ores on
the surface arc of Low grade and intimately interbanded with the inclos-
ing rock, hut they may fairly be regarded as indicating extensive ore
bodies below the surface, probably of great economic value.

The iron ores in association with the traps near the base of the Keewa-
tin in the Hunters Island region and north of the Atic Oban and Seine
rivers arc well known to western geologists. In the former locality they
are associated with jasper and are the extension of those great ore bodies
which form one of the wonders of Minnesota. In the latter locality the
ores are known to exist in extensive deposits and are of very high grade,
running as high as 70 per cent of metallic iron. Here as a rule no jasper
is associated with them. The ores of the same belt of Keewatin rocks
in which these occur, where found in the vicinity of Rainy lake, are often
so highly titaniferous that they are of little value in the present stage of
metallurgic science, but this seems to he but a local phase due to local
causes.

The ores of the third horizon of the Steep Rock series are somewhat
problematical, hut there are indications of extensive ore bodies in these
rocks.

Gold. — Gold has been mined in the Lake of the Woods in a feeble and
halt-hearted way for many years, hut the industry has languished under
many difficulties and misfortunes. Most of the quartz, however, is ex-
tremely rich, but the mining in almost every ease has been conducted
unscientifically, and the geologic problems connected with it have never
been properly worked out. Most of the gold-bearing quartz veins have
been found in the Keewatin rocks; but some of them, and these of
the richest, occur in granites, probably eruptive, usually coarse-grained
and chloritic, and somewhat resembling the quartz porphyry of the Atic
Oban river. These latter rocks are frequently found to contain very rich
auriferous quartz veins. The gold-bearing quartz porphyries of Harold
lake (north of the Seine river and about three miles west of Steep Rock
lake) are probably of the same age as the Margaret lake quartz porphy-
ries, though geographically the two are disconnected. It is possible that
the granites in the hake of the Woods, which contain auriferous quartz
veins, are of the same era of eruption as these.

Nich liferous DioriU . Nickeliferous diorite has been recently discovered
in the vicinity of Rat portage, but as yet none has been found containing
a high percentage id' nickel.

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA
Vol. 4, pp. 349-360 August 7, 1893

THE LAURENTIAN OF THE OTTAWA DISTRICT*

BY R. W. ELLS

(Read before the Society December 29, 1892)

CONTENTS

Page

Views of earlier Writers 349

Present View 350

Earlier Divisions of the Laurentian 351

Scope of the present Paper 351

The Laurentian Limestone and Gneiss 351

Origin of the Term Laurentian 352

Sir W. Logan's Investigation of the Laurentian Structure 352

Summary of Sir W. Logan's Laurentian Section 353

Eecent Investigations necessitate Change in the Section 854

The Anorthosite Masses north of Saint Jerome 354

Tremhling Mountain Section reexamined 354

Region between Anorthosite Area and Gatineau River 355

The Laurentian Gneiss and Limestone . . : 356

Their Thickness 356

Their stratigraphic Relation 357

Their physical Characteristics 357

Associated intrusive Rocks 358

Resume' and Conclusions 359

Views of earlier AYriters.

In discussing the structure of the Laurentian rocks, as developed in
the valley of the Ottawa river, their characteristics, as given in the first
report of the late Sir William Logan, in 1845-'46, on " The Laurentian
of the Upper Ottawa," may here be presented. After stating that a low
anticlinal crosses that river between the mouth of the Mattawa and the
foot of Lake Temiscamingue, he says :

" The lowest rocks which this undulation brings to the surface are of a highly
crystalline quality belonging to the order which in the nomenclature of Lyell is
called metamorphie instead of primary, as possessing an aspect inducing the theo-
retic belief that they may be ancient sedimentary formations in an altered condi-

* Published by permission of the Director of the Geological Survey of Canada.
LII-Bull. Okoi,. Soc. Am., Vol 4, 1892. (349)

350 R. W. ELLS — LAURENTIAN OF THE OTTOWA DISTRICT.

tion. Their general character is that of syenitic gneiss. Their general color is
reddish, and it arises from the presence of reddish feldspar, which is the prevailing
constituent mineral. The feldspar is, however, often white or bluish-gray. The
rock is in no case thai I have seen without quartz. Hornblende is seldom absenl
and mica very often present. The prevailing color of the quartz is white, hut it is
often transparent or translucent. The hornblende is usually black and sometimes
green. The mica is often black, frequently brown, and generally of a dark tinge-
The rock (carefully distinguished from dikes) is almost universally small grained.
and though the constituent minerals are arranged in parallel layers, no one con-
stituent so monopolizes any layer as to exclude the presence of others, but even in
their subordinate arrangement there is an observable tendency to parallelism ; a
thick bed of reddish feldspathic rock, for example, will, in section, present a num-
ber of short dashes of black hornblende or Mack mica, all drawn in one direction,
destitute of arrangement apparently, except in regard to their parallelism, or it
will be marked by parallel dotted lines, composed of these minerals. The constit-
uents of these lines will be interrupted irregularly, and before one ends another
will commence above or below it, the lines interlocking among one another.
Sometimes these continuous parallel black belts will run in the rock for considera-
ble distances or it will be barred by parallel streaks of white quartz or white
feldspar, in which, as well as in the red part, these dark and dotted lines will occur.
The same description of arrangement will be found where the whole ground of the
rock is white instead of red, and then the red feldspar will occasionally constitute
streaks. There is no end to the diversity of arrangement in which the minerals
and the colors will be observed, hut there is a never-failing constancy in respect to
their parallelism, which, however, though never absent, is sometimes obscure."

In the Geology of Canada, 1863, page 23, it is stated that —

" Very large masses of this rock are frequently coarse grained. These are usually
very feldspathic, the feldspar being in cleavable masses, often attaining an inch or
more in diameter, which the mica and the quartz, often accompanied by horn-
blende, and the former sometimes replaced by it, are distributed among the feld-
spar in such a manner as to give a reticulated aspect to the surface of the rock.
Beds of this character are sometimes thin, but when thick, which they usually
are, might on first inspection Lie mistaken for intrusive igneous instead of altered
sedimentary masses.

"The dip of the strata is generally at high angles, hut many undulations and
contortions exist. Some of the former give northern : others, southern dips."

Present View.

•
It will be seen from the preceding quotations that the views then held

as to the Laurentian rocks regarded them as almost entirely of sedimen-
tary origin, and that these were subsequently altered by metamorphism.
While it is evident from the clearly interstratified character of many of
the beds, such as gneiss, quartzite ami limestone, that these have been
produced from true sedimentary deposits in the same way as the Potsdam
and Calciferous <>( a later date, it has been very conclusively pointed nut

EARLIER DIVISIONS OF THE LAURENTIAN. 351

by the work of Lawson around the Lake of the Woods and b}r that of
Bell and Barlow in the Sudbury district that a very considerable portion
of the more syenitic mass must now be regarded as truly of eruptive
character. These masses, which are sometimes syenitic or granitic, in
places assume a gneissic structure, a peculiarity also sometimes observed
in the more recent syenitic and granitic masses of eastern Quebec and
New Brunswick. The same conclusions as to the origin of much of the
so-called syenitic gneiss will apply to large portions of the rock in the
area north of the Ottawa more particularly under consideration.

Earlier Divisions of the Laurentian.

Tn the earlier reports and on the great geologic map of Canada, 1866,
the Laurentian was divided into two portions — a lower, comprising the
gneiss and limestones, and an upper, which embraced the great areas of
anorthosite or labradorite rocks, found more particularly at that date to
the northwest of Montreal, near Saint Jerome.* No attempt was at that
time made to separate the calcareous portion from the gneissic, and in
fact the former was then regarded as an integral part of the whole,
occurring as regularly inters tratified beds often of great thickness, at
different points in the column representing the entire thickness of the
Laurentian rocks.

Scope of the Present Paper.

In this paper we propose to reconsider the typical section upon which
the great thickness of the supposed sediments, comprising a total of over
32,000 feet, was based, and to show that, in the light of the explorations
carried out during the last fifteen years, certain modifications of the
arrangement of strata as there laid down must be made.

The Laurentian Limestone and Gneiss.

The development and distribution of the limestones of the Laurentian
plays a very important part in the determination of the structure and
thickness of the whole, since in some places the calcareous bunds are
exceedingly limited, having a thickness of not move than live to ten feet,
or even less, while in other places this thickness increases to several
hundreds of feet. Thus, in a section published by Logan in 1845 of the
High falls of the Madawaska, representing a, thickness of 1,350 feet, the
limestone is noted as occurring in seven bands, the thickness of which
varies from less than one foot to nineteen, in which latter, however,

*Se.e map published in atlas, Geol. Canada, 1863.

352 R. W. ELLS — LAURENTIAN OF THE OTTOWA DISTRICT.

several corrugated bauds of gneiss are included, the whole thickness of
the limestone representing less than forty-six feet, and the greatest
development of the calcareous members being near the top of the section.
The gneiss is of several kinds, but mostly reddish, grayish, hornblendic
or rusty. From the character of the section, it is evident that the greater
part lies below the calcareous portion of the system or forms the lowest
part of that division.

Origin of the Term Laurentian.

The term Laurentian, as applied to the lowest system in Canadian
geology, first appears in the report for .1852-'53. It was founded on the
name Laurentian given by Mr Garneau, of Quebec, to the range of hills
on the north side of the Saint Lawrence river, which are composed prin-
cipally of the rocks of this system. In this report the description of the
country west of the Ottawa and north of Kingston on the Saint Law-
rence is by Mr A. Murray, and therein he describes a similar series of
grayish and reddish gneisses with crystalline limestone. The latter,
however, has a much greater development than in the section on the
upper Ottawa. Intrusive masses of red granite are noted at various
points, which cut transversely across the gneiss. The structure of the
limestone in places is held to be interstratified with the gneiss, but at
other points it appears on either side of an anticlinal in the gneissic
rocks.

Sir W. Logan's Investigation of the Laurentian Structure.

The principal work on which the structure of the Laurentian has been
based for many years was done by Sir William Logan and his assistant in
1853. in the Grenville district, north of the Ottawa river. This area is
situated about midway between Ottawa and Montreal, and the diffi-
culties he encountered in the attempt to unravel what has long proved a
puzzling problem were very great. The country at that time was almost
entirely a wilderness, small sections only being opened up for settle-
ment, densely wooded and, in places, largely drift-covered. Short trav-
erses were made along some of the larger lakes and on the principal
streams or by means of tracks cut through the forest. Of the difficulties
as to the structure, Sir William says :

" Bands of crystalline limestone are easily distinguished from bands of gneiss,

but it is scarcely possible to know, from mere local inspection, whether any mass
of limestone in one pari is equivalent to a certain mass in another. They all re-
semble one another more or less Lithologirally, ami although masses are met with,
running for considerable distances rudely parallel to one another, it is not yet

INVESTIGATIONS OF SIR W. LOGAN. 353

certainly known whether the calcareous strata are confined to one group, often
repeated by sharp undulations, or whether it is probable there are several groups,
separated by heavy masses of gneiss. . . . The dip avails but little in ascer-
taining this, for in the numerous folds with which the formation is wrinkled these
dips must frequently be overturned, and the only reliable mode of pursuing the
investigation and of making even the limestone available for working out the
structure is to patiently and continuously follow out the outcrop of each important
mass in all its windings, as far as it can he traced, until it becomes covered up by
superior unconformable formations, is cut off by some great dislocation, or disap-
pears by thinning away to nothing."

The attempt Avas therefore made in this district to work out the struc-
ture of the Laurentian limestone bands by tracing out their outcrops, an
undertaking which, in the unsettled and wooded character of most of this
region, was to a large extent impossible of accomplishment, especially in
a country to a large degree occupied by rugged ranges of mountains. To
make the work still more difficult and unsatisfactory, Sir William was
obliged to entrust it to men entirely without scientific training of any
kind and ignorant of the simplest points in regard to geologic structure,
more particularly when overturned strata or distortions, arising from the
presence of intrusive masses, complicated the problem. But little at-
tempt was made by his assistants to record strikes and dips, and, as the
outcrops were frequently concealed by drift over long areas or terminated
by thinning out or faulting, the joining of widely separated points, on
the hypothesis that these represented portions of the same continuous
band, of necessity produced a structure which was difficult to clearly
comprehend.

Summary of Sir W. Locian's Laurentian Suction.

The structure of the Laurentian deduced by Logan, largely from the
labors of his assistants, and summed up in the statement given in Geology
of Canada, 1863, known as the Trembling Mountain and Lake section,
may be summarized as follows :

1. The mass of orthoclase gneiss composing Trembling mountain,

thickness unknown, estimated 5,000 feet.

2. Crystalline limestone of Trembling lake 1,500 "

3-9. Four other bands of orthoclase gneiss in masses of 1,580 to 4,000

feet, separated by hands of crystalline limestone, in thickness

respectively from 20 feet to 2,500 feet, in all 15,750 "

10. Anorthosite, into which the upper band of orthoclase gneiss was

supposed to pass, thickness entirely conjectural 10,000 "

The whole supposed to present an ascending series ami aggregat-
ing 32,250 "

354 r. w. ells — laurentian of the ottowa district.

Recent Investigations necessitate Change in the Section-.

Within the last forty years the settlement and opening up of this
country has gone forward at a comparatively rapid rate. Great areas
have been cleared, and roads penetrate the townships in all directions
and extend northward along the principal rivers for over one hundred
miles, so that cross-sections are readily afforded and areas easily studied,
concerning which thirty or forty years ago the information was merely
conjectural; from the work of late years, therefore, it has heen found
necessary to make very important changes in the section, as just stated.

The Anorthosite Masses north of Saint Jerome.

In the eastern portion the study of the anorthosite masses north of
Saint Jerome by Dr F. D. Adams has conclusively shown that these are
of intrusive origin, since in many places they cut directly across the
strike of both the gneiss and limestone, while in others they have come
to the surface in long dike-like bands along the lines of sedimentation of
the gneiss. With the anorthosite proper are sometimes associated, more
particularly along the lines of contact with the gneiss, zones of gabbro
rock, while pegmatization is frequently seen in the former as we approach
the junction.

Trembling Mountain Section Re-examined.

A careful reexamination of the Trembling Mountain section westward
to the Iroquois chute on the Rouge river, and which was formerly re-
garded as an ascending one, shows that this view cannot be maintained.
In this space no less than three anticlinals with their corresponding
synclinals occur, while the section is further complicated b}^ faults of
very considerable extent. Of the hands of limestone said to occur there,
only one. namely, that of Trembling lake, was found, and this hand,
instead of occurring as an interstratified portion of the orthoclase-gneiss
scries, presents the form of a synclinal with converging dips in the un-
derlying gneiss both on the east and west sides of the lake, the western
flank of the Trembling mountain, which comes down to the east shore
of the lake, having a regular dip to the northwest of 60°, upon which the
limestone is seen to rest and to form part of ;i small island in the lake,
while on the west side of the lake great hills of gneiss, similar to that of
Trembling mountain, occur mid show a southeast dip toward the water
of from 40° to (.M)°. The Limestone itself, which from its position forms
the lowest calcareous member given in the original section, shows first
at the discharge of the lake from the south end in a band exposed for

RE-EXAMINATION OF TREMBLING MOUNTAIN SECTION. 355

about fifty feet, It appears also in several small islands near the center
and northern half of the lake, where it has at one place a breadth of
about 75 feet. In its northern part this hand changes its course from a
nearly north direction to one nearly at right angles to it, and appears to
be abruptly terminated against the bold walls of gneiss which extend
along the west shore of the lake. The remaining part of the section
crossing Great Beaver, Long and (liven lakes shows no limestone in any
portion, with the exception of a small outcrop from two to three feet in
thickness, of impure character, associated with gray and rnsty gneiss on
a small island near the north end of Long lake. The timber along the
shores of this lake being recently burnt off, a succession of ledges of red-
gray gneiss of the usual aspect is disclosed, which here have a general
dip to the west, the reverse dip to the east being clearly seen in the gneiss
ridges which extend for some distance along the east side of the Rouge
river below the Iroquois chute. It is but just to say that in the com-
pilation of this section the notes of survey and of the geology as well
were furnished by one of Sir William Logan's assistants, whose techni-
cal knowledge was limited and employed in making a topographic
sketch of the area in question.

The thickness of the Trembling Lake band of limestone is difficult to
estimate, but it is not apparently great, since, from the portions exposed,
at no point is there more than fifty feet in vertical thickness seen. The
area beneath the water is uncertain, and any attempt to estimate it in
such a folded series of strata would be only conjectural.

Region between Anortiiosite Area and Gatineau River.

In the region embraced between the Anortiiosite area north of Saint
Jerome on the east and the river Gatineau on the west, a distance of
about eighty miles, several traverses have been made both by canoe
along the lakes and rivers and by measurements along the roads which
have been opened up in the country north of the Ottawa, and thus a
very good opportunity has been presented of studying the structure in
detail over a very considerable area, It will be observed that in all the
reports, both of Logan and Murray, on the Laurentian the folded and
sometimes overturned character of the strata is pointed out. The great
resemblance in the character of the gneiss at the various horizons, sup-
posed to be separated by the different limestone bands, and the great
similarity in the bands of the limestone as well, is also frequently noted.
A close examination of the limestone outcrop throughout the whole
eighty miles of the section indicated has led us to the conclusion that
in nearly every case the limestone bands occupy well-defined synclinals,
which are separated by anticlinals in the underlying gneiss ; that in

356 K. W. ELLS— LAURENTIAN OF THE OTTOWA DISTRICT.

those cases where any considerable quantity of limestone appears to be
overlaid by gneiss in regular sequence, such superposition of the gneiss
is due to overturned strata, and thai sometimes gneiss is brought against
the calcareous measures by lines of fault. Abrupt changes of dip and
strike arc frequent, and in occasional sections, displayed along the shores
of some of the larger inland lakes, the repetition of the folds into well-
defined synclinals of limestone, separated by anticlinals of gneiss, occur
formany hundreds of yards and reveal this feature of the structure very
clearly.

Further, it has been found impossible to trace any particular band of
limestone to any considerable distance continuously. Masses of lime-
stone are often local in their development, presenting frequently lenticu-
lar forms which are thick near the center and thin off toward the extrem-
ities. They are often terminated abruptly by dislocations of the strata
or by the intrusion of other rock masses, and frequently the synclinal
structure in the gneiss can be seen for a long distance after the ending
of the calcareous overlying portions which may have been removed by
by denudation. In certain areas the synclinals follow one another in
quick succession, while the limestone maybe exposed for only a few
hundred yards or feet in each. In many places also there is a very
heavy covering of clay drift and sand, which conceals both the gneiss
and limestone. The latter is rarely seen except in valleys, the hills
where not of intrusive syenite or anorthosite being of the harder and
more feldspathic variety of gneiss, often interlaced with intrusions of
feldspathic rock or pyroxenic dikes.

While it is impossible to give in a paper of this kind such data as
strikes and dips on which the theory of structure here presented rests, it
may be here stated that throughout the section of eighty miles or more
from east to west the limestone occupies the synclinals in the gneiss
almost without exception. It will, however, be understood that in the
lower part of the calcareous portion certain thin bands of limestone are
interstratitied with the grayish and rusty gneiss which forms the upper
portion of the stratified gneiss series, and thus a gradual upward passage
from the gneiss into the limestone is presented, but in no observed case
are these interstratifications of gneiss of any great thickness, and their
relations to the overlying calcareou- beds can be easily recognized.

The Laurentian Gneiss and Limestone.

Their Thickness. — It is, of course, almost impossible to arrive at any
correct conclusions as to the thickness of the gneiss or limestone in a
series so twisted and so faulted as the Laurentian. Perhaps the best
section for this purpose is found on the Rouge river from a point about

THE GNEISS AND LIMESTONE. 357

six miles above its mouth, along the road which follows down the east
bank and alongside of which for several miles cliffs of grayish and
reddish-gray gneiss extend.

The limestone does not appear on the east bank of the river, but the
directly underlying rusty gneiss forms the upper member of the section
here exposed, the calcareous portion showing in small ledges on the west
side not far away. The series of gneisses have a general strike of N. 20° E.
magnetic, the variation being about 12° west, and the dip is to the north-
west at angles of 65° to 80°. The section is exposed for over two miles
across the strike, as seen along the road, and in this distance no limestone
appears, but in the southern extremity of the section, about two miles in
rear of Calumet station, it shows in low-lying ledges near the top of the
high hill at this place. Supposing that there is no break in this section,
there would be at this place not far from 10,000 feet of continuous
reddish and reddish-gray gneisses beneath the limestone. It is evident
that such figures, however, cannot be taken as accurately stating the
real thickness at this point, as faults and repetitions of strata may occur
at several places.

Their stratigraphic Relation. — The rocks underlying the limestone in
descending order, for we now assume the calcareous portion to form the
summit of the Laurentian sedimentary and mctamorphic series, may
be thus stated :

Limestone in thin hands with interlaminations of rusty and grayish
gneiss, the bands of limestone having a thickness from a few inches to
several feet, the gneiss sometimes with a thickness of ten to fifty feet,
shading downward into grayish and blackish gray, often garnetiferous
gneiss, with certain portions of a reddish shade from the presence of red
orthoclase. With these are often associated, more particularly in the
upper part, beds of quartz rock or quartzite, which sometimes reaches a
thickness of several hundred feet. The above are all found to be well
stratified.

Reddish-gray gneiss, with the indications of stratification less easily
seen and in places with foliation only. This underlies the well-banded
gneiss of the upper part of the section, and in certain portions even the
foliation becomes so obscure as to be indistinguishable except in large
well-weathered masses.

Their physical Characteristics. — The limestone portion in its lowest part
has numerous inclusions of the rusty gneiss, which have apparently
been drawn out and twisted into long serpent-like forms, sometimes
in bands of ten to fifteen feet in length; in other cases the inclusions
are small and have more the appearance of pebbles. The limestone
itself is frequently intensely crumpled, sometimes in minute crinklings;

LIII— Bull. Geol. Soc. Am., Vol. 4, 18'J'J.

*

358 IE W. ELLS — LAURENTIAN OF THE OTTAWA DISTRICT.

•

in other places in large corrugations ; but in the upper part of the mass
these frequently disappear and the strike and dip can be readily seen.
Occasionally the subjacent gneiss is crumpled in a similar manner, but
this is not the case as a ride. In certain areas also the limestone mass
contains well-rounded pebbles or masses of quartzose rock and grayish
gneiss, presenting the aspect of a true conglomerate. This character can
be well seen in a low cliff one mile and a half in rear of Calumet station,
on the Canadian Pacific railway, as well as at many other points around
the shore of the inland lakes, conclusively showing that this conglom-
erate is widely distributed.

Associated intrusive Rocks.

In addition to the gneiss and limestone, which may be regarded as
forming the great mass of the Laurentian rocks, certain areas of intrusive
rocks present features which are worthy of something more than a merely
passing notice. Of these some are of large extent, as in the case of the
anorthosite areas north of Saint Jerome and the syenite masses of Gren-
ville and Chatham, while other masses, though not so conspicuous as
these, are equally important as having exercised a marked influence
upon the occurrence of the principal economic minerals of the district.

Of these no less than six. if not seven, clearly distinguishable periods
of intrusion can be recognized. In addition to the large masses of anor-
thosite and syenite just referred to, presumably the large areas of
augen-gneiss seen more particularly in the country adjoining the upper
Rouge river belong to this class, since they have without doubt exercised
a marked effect upon the strike and dip of the gneissic and calcareous
rocks with which they are in contact. The masses of augen-gneiss pre-
sent no trace of stratification and very rarely even of foliation.

Of smaller intrusions may be mentioned the great series of pyroxenic
dikes which penetrate the irneiss of the phosphate district, and which
are generally of some shade of green, and the quartz and feldspathic,
generally white-weathering, dikes which are also prominent in the same
area. Certain black, fine-grained trappean dike- are also frequent which
cut both the preceding, some of which can be traced for many miles
crossing the strike of both the gneiss and the limestone. In regard to
the age of these trappean dikes it may he said that while, they cut the
limestone transversely they are cut off by the mass of the Grenville
syenite.

In connection with this syenite also is a mass of intrusive porphyry,
evidently from the mode of its occurrence of later date. Other smaller
intrusions, but recognized at points over a very wide area, are of a very
coarse, black hornblende rock, in which the hornblende is the chief

• RESUME AND CONCLUSIONS. 359

mineral constituent recognized. This rock resembles closely the black,
coarse dikes which are found in connection with several of the intrusive
mountains of the eastern townships.

Of the pyroxenic and feldspar dikes it may be said that in earlier re-
ports they are described as integral portions of the gneiss formation. In
places they extend along the lines of bedding, and are of the nature of
bedded dikes, but in others they cut transversely across the strike of the
gneiss, and their intrusive character is further established by the dis-
placement and alteration of the strata in contact and by the formation
of crystals of various kinds. The effect of the intrusion of the pyroxene
upon the occurrence of economic minerals as well is easily seen at many
of the apatite mines of the Buckingham district, and upon the establish-
ment of their intrusive character the occurrence of the phosphate is more
readily explained. It has been found by careful examination at many
points that this apatite occurs, not in the gneiss itself, but in the mass of
the intrusive pyroxene dikes ; and, further, that its presence in workable
quantity is always near the contact of the dike with the gneiss. Occa-
sionally apatite is found in the limestone overlying, but only in detached
crystals, along with pyroxene and mica and graphite. The same effect
is visible in the occurrence of the mica and graphite, the workable de-
posits of which arc cither in the mass of the intrusive rock or in the
gneiss and limestone adjacent.

Resume and Conclusions.

Reviewing, then, briefly the conclusions as to structure arrived at by
the writer, the succession, in ascending order, in the district under con-
sideration, may be thus stated :

1. Reddish-gray gneiss without distinct signs of bedding or stratifica-
tion, hut with a foliated structure. In connection with this are great
masses of syenite-gneiss and augen-gneiss, in winch foliation is for the
most part entirely wanting, and much of which is presumably intrusive.

2. Reddish orthoclase gneiss, interst rati tied with black hornblende,
grayish quartzose and garnetiferous gneiss, with beds of grayish quartzite,
and rusty may, often highly quartzose, gneiss, the whole showing a well-
stratified arrangement of beds, generally with very distinct appearance
of sedimentation, many of the beds in the upper part having the aspect

, of regularly deposited layers of quartzose sandstone.

•'!. The grayish and rusty gneiss passes upward gradually into the cal-
careous portion of the system, thin bands of limestone first appearing as
interstratified beds along with the gneiss, the intcrstratification becoming
less as we ascend the scale, till, through scattered, twisted inclusions, the
gneiss disappears and the rock becomes a regular crystalline limestone,

360 R. W. ELLS — LAURENTIAN OF THE OTTAWA DISTRICT.

which forms the upper member of the Laurentian proper, at least east of
the Ottawa river. West of that river, in the area north of Kingston, the
section of the Archean may be completed upward thus:

I. A series of schistose rocks, highly metamorphic, comprising talcose,
sericitic, chloritic and micaceous schists, described in earlier reports as
the Hastings scries. This overlies the crystalline limestone of the
upper Laurentian and is believed to represent the lower member of the
Huronian system. These schists are the exact lithe-logic equivalent of
the Huronian rocks of the anticlinals of the eastern townships, as in
Sutton mountain and elsewhere, and also of the lower part of the Huro-
nian of New Brunswick. In both the last-named areas they are over-
laid by more typically volcanic portions of the Huronian, such as the
diorites, felsites, etc., and these in turn are succeeded upward by the
conglomerates, quartzites and slates of the lower Cambrian.

Under the present arrangement of the Laurentian of Quebec the par-
allelism with the rocks of the system as displayed in southern New
Brunswick is very close. Thus, according to the measurements of Messrs
Bailey and Matthew, published in the Report of the Canadian Geologi-
cal Survey for 1870-71, the rocks of the system are there divided into a
lower and an upper portion; the former comprising the usual variety
of grayish and reddish-gray gneiss with syenitic and dioritic rocks, in
all estimated at 2,500 feet, the latter consisting of dark-grayish and
cream-colorecl dolomitic limestone with rusty grayish quartzose gneiss
and quartzite capped by grayish limestone and black graphitic shales.

North of the Ottawa neither the Huronian rocks of the Hastings series
nor the quartzites and other rocks of the lower Cambrian appear. A
short distance below the city of Ottawa the gneiss and limestone of the
upper Laurentian are overlaid by nearly fiat-lying ledges of Potsdam
sandstone, which passes upward gradually and conformably into the
Calciferous limestone formation. North of Saint Jerome also a limited
outlier of the lower Calciferous is seen to rest upon the Laurentian.
Further down the Saint Lawrence toward the city of Quebec the for-
mations resting directly upon the Laurentian are the ('hazy and the
Trenton, the same general horizontality of the measures being preserved,
except where broken by lines of fault.

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA
Vol. 4, pp. 361-370 August 7, 1893

HEIGHT OF THE BAY OF FUNDY COAST IN THE GLACIAL

PERIOD RELATIVE TO SEA-LEVEL, AS EVIDENCED BY

MARINE FOSSILS IN THE BOWLDER-CLAY AT

SAINT JOHN, NEW BRUNSWICK*

BY EGBERT CHALMERS

{Read before the Society December 29, 1892)
CONTENTS

Page

Locality, Area and Thickness of Bowlder-clay Deposit 361

Direction of Striae on Rocks 3<>2

Topography of District North of Bowlder-clay Deposit 362

The Bowlder-clay 363

Source of the Materials composing it 363

Its stratified Portions 363

Section at the Fern Ledges 363

Section at Negrotown Point 365

Fossil marine Shells 366

Their Occurrence in the Bowlder-clay at Negrotown Point 366

Their Occurrence in the Bowlder-clay of the Saint Lawrence Valley 366

Their Occurrence in the Drunilins near Boston 367

Their Occurrence in the Leda Clay and Saxicava Sands of New Brunswick. 367

The Height of the Land and the Mode of Deposition of the Bowlder-clay 367

Oscillations of the Ice-margin 369

Climatic Conditions during Deposition of the Leda Clay and Saxicava Sands. . 369

Conclusions 369

Discussion 370

Locality, Area and Thickness of the Bowlder-clay Deposit.

The occurrence of a thick deposit of bowlder-clay on the Bay of Fundy
coast just west of Saint John harbor, containing intercalary seams of

♦ Published by permission of the Director of the Geological Survey of Canada.
LIV— Bull. Gj:ul. Sue. Am., Vol. 1, 1892, (361)

302 R. CHALMERS — BAY OF FUNDY COAST TX THE GLACIAL PERIOD.

stratified clay, was referred to in my report on thesurface geology of
southern New Brunswick* This bowlder-clay forms a marginal strip
of the land from Carleton to Duck cove, one and a half to two miles in
length, and in the hank facing the sea rises from 40 to 60 feet in height
above the beach. The part of it jutting out into the hay and forming a
headland opposite Partridge island is called Negrotown point. A break-
water lias been coastructed there. The bowlder-clay at this point attains
its greatest width, being 1,033 yards across in a north and south direc-
tion. At the Fern ledges, so called, from three-quarters of a mile to a
mile west of the breakwater, it narrows to 215 yards, again widening out.
however, before being overlapped at Duck eove, a little beyond, by fos-
siliferous Leda clay and Saxicava sands. At the Fern ledges the exposed
thickness of the bowlder-clay, including the intercalary stratified seams,
is by actual measurement 61a feet, but its thickness decreases to the
eastward.

Direction of Stride on Rocks.

The ledges which come out on the shore from underneath the bowlder-
clay here are well striated, the direction of the striae being S. 2° W., S.
2° *E., S. 10° E., S. 20° E., S. 80° E., S. 56° E., S. 60° E., and S. 65° E.
(true meridian), and several of these courses appearing often on the same
surface. The stoss-side is invariably to the north. These divergent
striae are noteworthy and indicate very clearly the action of several
bodies of ice as they debouched into the sea.

To the east of the Fern ledges no rock exposures are seen along the
shore, and the bottom of the bowlder-clay is covered up by beach sands
and by the bowlders and debris which have fallen down as the bank is
being eroded by the sea.

Topography of the District north of the Bowlder-clay Deposits.

Immediately to the north of this marginal belt of bowlder-clay and
occupying the peninsula between the mouth of the Saint John river and
the Bay of Fundy lies a group of hills from 175 to 225 feet high, known
as Carleton heights. The rock surfaces on many of these are bare and
exhibit their highly glaciated condition. The main courses of the stria-
are S. 2° E. and S. 16° W. (true meridian).

The district around the mouth of the Saint John river has a hilly and
broken surface, but the larger portion of it lies, nevertheless, below the
220-foot contour line. It is a locality which has been very favorably
situated for the nourishment of glaciers. Accordingly we find here

♦Ann. Rep. Geol. Surv. Canada, vol. iv, pari N, 1888-89.

THE BOWLDER-CLAY. 363

abundant evidence of the former existence of land ice, and, from the
position of the stria? and the character of the bowlder-clay, the conclu-
sion that the ice which covered the district flowed out toward the open
waters of the Bay of Fundy is beyond question.

The Bowlder-clay.

Source of the Materials composing it. — Field investigations reveal the fact
that the materials composing the great mass of the bowlder-clay are ob-
viously derived from the rocks lying immediately to the north. These
rocks belong to the pre-Cambrian, Cambrian and Carboniferous Bowl-
ders of these systems, consisting of granites, gneisses. Lower Carboniferous
conglomerates, diorites or diabases, limestones, sandstones, slates, quartz-
ites, etc., are displayed in the debris along the foot of the bank, strewn
upon the beach, and also appear scattered throughout the mass of
bowlder-clay. Many of them are large, the gre*at majority being from 3
feet to 8 or 10 feet in diameter, and a considerable number are striated
and polished. At Negrotown point the largest bowlders are of Lower
Carboniferous conglomerate, the parent rock of which is from 3 to 10
miles to the north.

Clay and gravel, or rock debris, constitute the principal bulk of the
bowlder-clay. The uppermost parts are less compacted than the lower
and are capped by Saxicava sands in places. This renders it permeable
by water to some depth, and, in those parts which contain stratified
seams of 'clay, springs ooze out in the hank. Owing to this fact, and to
the foot of the bank being continually eroded by the sea, landslips are
of frequent occurrence and rapid denudation of the bowlder-clay is
taking place.

Its stratified Portions. — The stratified portions of the bowlder-clay arc
for the most part thin, and form irregular, lenticular seams in the heart
of the unstratified mass. They are distinctly laminated, and in some
places, as at the Fern ledges, the strata dip slightly northward, that is,
away from the shore. The material is a tough, dark red, brick-clay,
containing a few pebbles and bowlders, scarcely any of which exceed '.»
inches or a foot in diameter. These strati lied hands usually occur in
the middle of the bowlder-clay bank, being underlain and overlain by
unstratified deposits, often of considerable thickness.

Section at the Fern Ledges. — The following section of the bowlder-clay
at the Fern ledges will serve to illustrate its structure and character ; it
was carefully measured, in descending order, a lew feet to the west of the
section given in my report above cited:

3(34 R. CHALMERS — BAY OF FUNDY COAST IX THE GLACIAL PERIOD.

1. Unstratified bowlder-clay, with three or more thin seams or layers
of clay and sand interst ratified therewith. It contains pebbles and bowl-
ders of call sizes up to '.» inches or a foot in diameter, some of which are
striated. Theseams of clay and sand dipslightly northward or away from
the sea. The uppermost parts contain a good deal of sand, and have
apparently been worked over in the Saxicava sand period. The surface
of the ground is strewn witli bowlders from 2 feet in diameter downward ;
total thickness, 12.7 feet.

2. Typical, unstratified bowlder-clay, containing numerous glaciated
bowlders and pebbles; bowlders from 3 to 5 and 6 feet in diameter are
common; thickness, 25 feet.

3. Stratified, tough, dark-red clay, forming a wavy, lenticular seam,
distinctly laminated, the strata dipping slightly northwestward, hut
irregular and uneven, and not occupying a continuous horizontal posi-
tion, except very locally. To the west of the section it decreases in
thickness and runs down to within a few feet of the bottom of the bank;
to the east it first rises somewhat higher and then descends likewise,
diminishing in thickness till only a foot or two of it can he seen. It c< >n-
tains a few pebbles, and occasionally a bowlder — one 10 inches in diam-
eter was noticed. No fossils were detected in it ; thickness in the thickesl
part, 14 feet.

4. Unstratified bowlder-clay, the same as number 2. Bowlders 3 to
6 feet in diameter are numerous. These are strewn along the foot of the
hank as well as upon the beach. The total thickness of this bed is from
9 to 10 feet.

Following this lied (number 4) of bowlder-clay continuously westward
from the line of the section we find it, at a distance of 15 paces, resting
on the glaciated ledges. Here it is observed, however, to have only a
thickness of from 3 to 5 feet. The stratified seam overlying it has. as
stated above, also thinned out here, but is, nevertheless, well defined.
Striated rocks, with tins bed of bowlder-clay reposing on them, extend
continuously along the shore for about 90 yards farther west. There
is much variation in the direction of the striae. Eight or more different
courses of them occur on these ledges, varying from S. 2° W. to S. tio° E.
(true meridian). These, it is evident, must all have been produced by
the glaciers which laid down the bottom portion of the bowlder-clay
(number 4 of flic section); for before the ice which deposited the upper
portions of the unstratified beds uumbers 2 and 1 of the section) could
have striated the rock- it would have to work over the whole of the
deposits beneath it. thus destroying all stratification therein and reduc-
ing them to a pell-mell mass.

SECTIONS OF THE BOWLDER-CLAY. 365

Section at Negrotown Point. — This section was measured at a distance of
about a quarter of a mile west of the Negrotown Point breakwater. In
descending order the beds are as follows :

1. Typical bowlder-clay, unstratified, containing bowlders 2 to 5 feet
in diameter, most of them glaciated. The total thickness of this bed is
11 feet.

2. An irregular, wavy, lenticular seam of stratified bowlder-clay, not
in horizontal position, and varying in thickness from a few inches to a
foot or more.

3. Bowlder-clay the same as number 1, and containing similar bowl-
ders but apparently bedded in some parts. In this division of the bowl-
der-clay series the following species of marine shells were found : Yoldia
(Ledai) arctica, abundant and well preserved, often with the epidermis
on ; Bcln mix crenatus ( fragments), Saximva rugosa, Mya arenaria (a single
valve),' Macoma calcarea, Nucula tenuis (much broken), Buccinvm sp. (?),
probably undatum (a fragment), etc. All the species except Yoldia are
quite rare. They appear to be indiscriminately scattered through the
mass. Thickness of this part of the bowlder-clay, 6 to 10 feet.

4. Stratified, dark red, tough clay, distinctly laminated, with a few
bowlders of the same kinds of rocks as those met with in the unstratified
portions; the deposit irregular and wavy, not in a horizontal position
and somewhat lenticular, or rather not maintaining the same thickness
for any distance. Layers of this division of the series are seen sometimes
to run up obliquely into and terminate in the unstratified bowlder-clay
immediately above, and in other places apparently to graduate into it.
Scattered throughout are shells of Yoldia {Leda) arctica, well preserved,
often in the bottom with the valves closed and the epidermis intact;
Nucula fin a is (broken), Balanus crenatus (fragments), Saxicava rugosa,
Macoma calcarea, Buccinum and Mya (fragments), and one or two unde-
termined species. Thickness, 4 feet.

5. The height of the whole bank here being about 45 feet, there still
remain 19 or 20 feet of it below the stratified fossiliferous portion,
number 4. For the space of some hundred yards both east and west of
the section, however, this lower partis concealed from view by landslides.
Nevertheless, it is evident that a thick bed of bowlder-claj7 underlies the
stratified seam, number 4 ; whether containing other stratified layers and
fossils it is at present impossible to say. No rock outcrops are visible,
nor is the bottom of the bowlder-clay in sight anywhere in the vicinity
of Negrotown point. The glaciation of Partridge island, which is in
Saint John harbor, about a mile distant from Negrotown point, was
apparently accomplished by the ice which moved out from the mainland.
The ice which produced a portion at least of the bottom bowlder-clay

366 K. CHALMERS — BAY OF FUNDY COAST IN THE GLACIAL PERIOD.

must therefore have extended some distance beyond the present coast
line; and from this fact the inference may he drawn that when it was
deposited (lie land stood as high as at present relative to sea-level and
perhaps higher.

Fossil marine Shells. ,

Their Occurrence in the Bowlder-clay at Negrotown Point. — The first dis-
covery of marine shells in the bowlder clay at Negrotown point was
made by YV. J. Wilson* my assistant, in 1891. Heavy storms during
the previous winter, accompanied by very high tides, had eroded and
undermined the bank to such an extent as to cause landslips, and
also to clean off the falling debris from the face of the slope, thus afford-
ing fresh exposures. The locality was examined by Baron Gerard de
Geer, of the Swedish Geological Survey, and on several occasions since
by myself, and I now feel certain the shells in the stratified portion of
the bowlder-clay at least are in situ, and lived in the sea along this coast
during the glacial period, and were entombed in these clays when the land
stood considerably lower than at present.

In regard to the shells found in the unstratified bowlder-clay, some of
them may have been pushed out in the deposits from the littoral into
deeper waters by land ice. The presence of Mya arenaria in these beds
along with Yoldia arctica, etc, may thus be accounted for. The irregular
line of contact between the stratified and unstratified beds, the gradual
changing of one into the other along this line, the fact of curving, irregu-
lar strata running up diagonally into the overlying unstratified mass in
many places, all tend, in my judgment, to show that the unstratified
fossiliferous bowlder-clay has also been deposited in its present situation
beneath the sea.

Their Occurrence in the Bowlder-clay of the Saint Lawrence Valley. —
Marine shells have been found by Sir J. William Dawson in the bowl-
der-clay of the Saint Lawrence valley, at Isle Verte, Riviere du Loup,
Murray bay and Saint Nicholas.^ the species comprising Leda truncata
of Brown, Yoldia arctica of Sars, Balanus hameri and Bryozoa, the two
latter adhering to bowlders and large stones, "evidencing," as the author
says, " that they had for some time quietly reposed in the sea bottom
before thev were buried in the elav.'"t

* I have to acknowledge my indebtedness to W. J. Wilson, my assistant on the Geological Srfrvey
of Canada, for the collection of shells obtained from the bowlder-clay at Negrotown point, and for
timely and valuable observations which his residence in Saint John enabled liim to make.

t Notes on the post-Pliocene Geology of Canada: Can. Nat.. 2d series, vol. vi. 1x71'. p. 25.

J Till or bowlder-clay containing an intercalary fossiliferous seam of clay occurs at Portland,
Main.'. Professor C It. Hitchcock gives a section of it in Geology of New Hampshire, part iii. p.
■jT'.e ''lit the fossils found in it do not seem to have been kepi separate from those collected in
other i'e< Is in that vicinity called Champlain, so that I am unable to correlate them h ith the fossils
of the Saint John bowlder-clay.

FOSSIL MARINE SHELLS AND THEIR OCCURRENCES. 307

Their Occurrence in the Drumlins near Boston. — Warren Upham and
others have discovered marine shells and fragments of shells in the
bowlder-clay hills called "drumlins" near Boston.* His list shows,
however, that the species are nearly all the same as those of the recent
period. Mr Upham explains the occurrence of these shells in the
drumlins by supposing that the ice of the glacial period ploughed up
certain marine beds inclosing them to the north and carried them for-
ward to form a portion of the material of these bowlder-clay hills.

Their Occurrence in the Lata < 'lay and Saxicava Sands of New Brunswick. —
Marine shells of Pleistocene age were found by G. F. Matthew and the
writer a number of years ago in clays and sands on the coasts of the Bay
of Fundy and Baie des Chaleurs, which have been correlated with the
Leda clay and Saxicava sands of the Saint Lawrence valley. Lists of
these shells were published in the reports of the Geological Survey of
Canada, etc.f The height of the terraced deposits in which the shells
occur clearly establishes the conclusion that when the lower fossiliferous
portions were laid down the land stood from 180 to 220 feet lower than
it is at the present day ; and as the Leda clay and Saxicava sands con-
taining these shells have invariably been found overlying the bowlder-
clay, it is naturally inferred that their deposition began about the close
of the glacial period and occupied a distinct and separate interval of
Pleistocene time.

The Height of the Land and the Mode of Deposition of the

BoWLDER-OLAY.

It is a view generally held by glacialists who have studied the Pleisto-
cene deposits and related phenomena of coast borders, especially within
the glaciated belt, that the land was subsiding during the period of
melting or retirement of the ice.'! The lower unstratified portion of the
bowlder-clay here was probably deposited during the greatest advance
of tin; hind-ice; this ice, as shown on a previous page, having extended
beyond Partridge island. It seems to have consisted mainly of sheets
flowing out from the Saint John and Kennebeckasis valleys which may

♦Proceedings of the Boston Soe. of Nat. Hist., vol. xxvi, 1888.

t Report of Progress, Geol. Surv. Canada, part EE, 1877-'78 ; Ann. Rep. Geol. Surv. Canada, vol. 1,
part GG, 1885.

t;J. D. Dana, Am. Jour. Sei., third series, vol. ii, pp. 324-330; vol. v, pp. 198-211; vol. x, pp. 168-183,
400-438; vol. xxiv, pp. 98-104. .J. W. Dawson, Bull. Geol. Soc. of America, vol. i, p. 318; Acadian
Geology, supplementary note to fourth .•■lit ion, 1891, p. 7. C H. Hitchcoqk, Geology of New Hamp-
shire, vol. iii, p. 27k. Professor Hitchcock is, however, rather inclined to the view that it was the
sea and not the land which changed level. Warren Upham, Bull. Geol. Soc. of America, vol. i, pp.
,r>i;:j-.">c>7. G. IB Stone, Am. Jour. Sci., vol. xl, pp. 122-144. Robert Chalmers, Ann. Rep. Geol. Surv-
Canada, vol. iv, 1888-89, pp. 10, Un ; Canadian Naturalist, vol. x, p. 54. G. M. Dawson, Report of Prog,
ess, Geol. Surv. Canada, 1877-78, pp. 133-1536.

368 K. CHALMERS — BAY OF FUNDY COAST IX THE OLACIAL PERIOD.

have been confluent, bui there were also glaciers from the adjacent val-
leys and from the hills in the vicinity of Saint John harbor. The
divergent courses of striae recorded in this paper indicate that the dis-
charge of these into the depression of the Bay ofFundywas not strictly
contemporaneous; but successive, for no single body of ice moving out
into an open bay would, in my judgment, be likely to produce striae
diverging 65 to 67° apart, even with the land more elevated than it now
is. Moreover, independent of the striation of this particular Ideality, we
have in the eastern provinces of Canada very good evidence of the ex-
istence and diverse movements of local glaciers throughout the whole
glacial period.-'- What the height of the coast district was at the time
this lower bowlder-clay was thrown down, however, cannot he deter-
mined with any degree of accuracy. In the later Tertiary it was "200
feet or more above the level at which it now stands relative to the sea.f
It may be stated that not only Partridge island, but the islands of
Campobello and Grand Manan, lying off the mouth of the Saint Croix
river, have been overridden by the land-ice. The latter is now sepa-
rated from the mainland by a strait or passage 45 to 50 fathoms deep and
from 8 to 9 miles wide. X Ice of such a comparatively local character as
has been shown to have occupied the eastern provinces of Canada in the
Pleistocene! could not, it seems to me, reach Grand Manan unless the
land were higher relative to the sea than at present.

But whatever views may be entertained regarding the height of the
land when the lower bowlder-clay referred to was deposited, the upper
or overlying glacial deposits, stratified and unstratified, were evidently
laid down when the subsidence of the land was in progress and had
perhaps reached its maximum. The stratified fossiliferous portion, from
its position and height above sea-level and the well-preserved condition
of a number of its contained fossils, unequivocally proves that the coast
must have then been from 100 to 200 feet lower than it now is. The
retirement of the ice at this time, whether caused by the subsidence and
consequent breaking away of its margin or by an amelioration of the
climate, or by both, does not seem to have been more than local, this
supposition being at least sufficient to afford an explanation of all the
facts. The irregular lenticular condition of the stratified portions and
the fact of tongues of these being interstratified with the overlying un-
stratified bowlder-clay indicate with tolerable certainty that they must
have been deposited iis we now find them along or near the ice-front.

*Glaciation of Eastern* Canada. R Chalmers, Canadian Record of Science. Montreal, April,
1889. Ann. Rep. Geol. Surv. Canada, L885 to L889.

fAnn. Rep. Geol. Sun. Canada, vol. iv, 1888-89, pp. 8, On.

X Ann. Rep. Geol. Surv. Canada, vol. iv, 1888 '89, pp. Is. 19 re.

I R. Chalmers, Ann. Reports Geol. Surv. Canada, L885 to L889. Trans. Roy. Soc. of Canada, 1886,
sec. ■», art. to. Canadian Record of Science, April, 1889, pp. 319-333.

relation of ice oscillation to deposition. 369

Oscillations of the Ice-margin.

ft is abundantly clear that there have been several oscillations of the
ice-margin. Not only do the stratified seams and irregular, roughly
horizontal breaks in places in the upper portion of the bowlder-clay
show such advances and recessions of the ice, but the divergent courses
of stria' likewise denote several ice-movements as stated and indicate
that the bottom portion of the bowlder-clay lias Keen formed by a num-
ber of successive accretions or additions of material. The whole of the
bowlder-clay in question would seem, indeed, to have beni produced in
a zone of oscillation of the ice-front, the ice retiring to and advancing
from the Carleton and other hills to the north. The later advances were
comparatively light, otherwise the older or first-formed beds would have
been ploughed up much more deeply than they are. This may, however,
be partly due to the continued subsidence, which at the close of the
glacial or commencement of the Leda-clny period amounted to 220 feet
below the present high-tide level, in which case these deposits may
really have been thrown down in a sea of considerable depth.

Climatic Conditions during Deposition of the Leda Clay and

Sa xi cava Sands.

The deposition of the Leda clay closely followed the last recession of
the ice and may, indeed, have been in progress before it finally disap-
peared from the bills around the mouth of the Saint John. The Leda-
clay fauna here does not denote such arctic conditions as prevailed in
the latter part of the glacial period, nor, indeed, in the Leda-cl&y period
in the gulf of Saint Lawrence. This has been shown by G. F. Matthew
and by Sir J. William Dawson.* The amelioration of climate following
the retreat of the ice was coincident with a rising of the land, as indi-
cated by the facies of the marine fauna found in the clays deposited in
the quieter bottoms and of that of the sands, etc, in the shallower sea
margins during the Leda-cl&y and Saxicava-s&nd period. No glacial
deposits are known to overlie these, or be inters tratified with them, on
the Atlantic coast of Canada.

Conclusions.

The conclusions drawn from the foregoing facts may therefore be thus
briefly summarized :

1. The bowlder-clay here described was deposited at or near the margin
of the land ice which flowed out from the Saint John and Kennebeckasis

*Notes on the post-Pliocene Mollusca of Acadia: G. F. Matthew, Canadian Naturalist, vol. vii

Supplement to the 2d ed. of Acadian Geology, 1878.

LV— Bum.. Gkol. Soc. Am,, Vol. 4, 1892.

370 R. CHALMERS— BAY OF FUNDY COAST IN THE GLACIAL I'KRIOD.

valleys, etc. The ice-froni was beneath the sea at the time the stratified
and overlying, unstratified fossiliferous portions were deposited. These
testify very clearly to several local oscillations of the ice-front and show
unmistakably thai this portion of the series was formed by a Dumber of
successive increments or additions of material, appearing, indeed, just as
if the ice had " dumped " it a number of times in succession over the
Carleton hills into the Pleistocene sea with little or no disturbance of the
preexisting beds.

2. The shells in the stratified portions of the bowlder-clay are in situ,
and have been entombed in it in a sea 100 to 200 feet or more in depth.
They are in too perfed a condition to have been transported in bowlder-
clay by ice, and, moreover, the .state of the beds in which they occur is
opposed to this view. Those found in the overlying, unstratified bowl-
der-clay may have had the shallow-water species now found buried in it
pushed out from the Pleistocene shore and thus mingled with the deep-
water forms. All the species denote an arctic or a subarctic climate and
a sea even colder than existed at the beginning of the Leda-cl&y period.

3. The land on this part of the Bay of Fundy coast during the deposi-
tion of this fossiliferous bowlder-clay must have been, therefore, loo to
200 feet or more lower than at the present day, relative to the sea.

4. As the stria' on the rocks underneath the bowlder-clay indicate
several ice movements varying in direction from S. 2° W. to S. 65° E.,
these and the formation of the lower bowlder-clay cannot all lie due to
one body of ice. The latter is therefore the product of several glaciers,
each successive one having worked overall the material beneath it down
to the rock surface.

discussion.

Air Warren Upham : The occurrence of Yoldia arctica as the only
plentiful species in the intercalated stratified -earns of clay met with in
the bowlder-clay at Saint John implies that the margin of the ice was
near when it inhabited the Bay of Fundy waters. This shell is now-
found living only in the Arctic ocean, and thrive- most, according to
Baron de (deer, in Spitzbergen, near the months of streams discharged
from glaciers and muddy with the line silt dm' to their erosion.

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA
Vol. 4, pp. 371-458, Frontispiece September 23, 1893

PROCEEDINGS OF THE FIFTH ANNUAL MEETING, HELD AT
OTTAWA, CANADA, DECEMBER 28, 29 AND 30, 1892

Herman LeRoy Fairchild, Secretary

CONTENTS

Page

Session of Wednesday, December 28 "72

Report of the Council 372

Report of the Treasurer 376

Election of Officers for 1893 378

Election of Fellows 378

Memorial of Thomas Sterry Hunt (with bibliography )v; by Raphael

Pumpelly 379

Memorial of" John Strong Newberry (with bibliography) ; by .1. F. Kemp. 393
Memorial of James Henry Chapin (with bibliography) ; by W. M. Davis. 406
On the Geology of natural Gas and Petroleum in southwestern Ontario

(discussion by I. C. White and II. M. Ami) ; by II. P. H. Drained 408

Note on fossil Sponges from the Quebec Group (Lower Camhro-Silurian)

at Little Metis, Canada (abstract) ; by J. Wm. Dawson 409

Evening Session of Wednesday, December 28 411

A fossil Earthquake (abstract) ; by W J McGee 411

Session of Thursday, December 2!) 415

Third Annual Report of the Committee on Photographs 415

Notes on the glacial Geology of western Labrador and northern Quebec;

by A. P. Low 419

Height of the Bay of Fundy Coast in the Glacial Period relative to Sea-
level as evidenced by marine Fossils in the Bowlder-clay at Saint John,
New Brunswick (discussion by Warren Upham) ; by Robert Chalmers. . 422
The supposed post-glacial Outlet of the Great Lakes through Lake Nipis-

sing and the Mattawa River ; by G. Frederick Wright 42:5

Notes on the Geology of Middleton Island, Alaska; by George M. Daw-
son. 427

Session of Friday, December 30 432

Evening Sessi< >n of Friday, December 30 434

The Huronian Volcanics south of Lake Superior (abstract); by C. It.

Van Hise : 4:!o

On two Overthrusts in eastern New York ; by N. II. Darton 4:i(i

Register of the Ottawa Meeting, 1892 440

List of < Mlieers and fellows of the < reological Society of America 411

Index to Volume 4 451

LVI-1'.ri.i,. GEor.. Sue. Am., Vor„ I, L89'2. (.371)

372 proceedings of ottawa meeting.

Session of Wednesday, Decembee 28

The Society met in the railway committee-room of the House of Com-
mons. President G. K.Gilbert presided during the several sessions of
the meeting.

At 10.20 a ni the President called the Society to order and after a word
of salutation introduced His Excellency, the * rOvernor-General of Canada.
Sir Frederick Arthur Stanley, who extended a hearty welcome to the
Fellows of the Society. Science, he said, was cosmopolitan and did not
admit of distinctions of race, creed or national boundary; as far as
science was concerned, all were one brotherhood. He assured the visitors
that they would be shown every hospitality while in the city. The
President made reply to the welcome of His Excellency, referring in
complimentary terms to Canadian hospitality.

The Council report was read by the Secretary as follows :

REPORT OF THE COUNCIL

To the Fellows of tin Geological Society of America,

in Fifth Annual Meeting, 1892:

Meetings of the Council. — During the past year the Council has held two
meetings, coincident with the meetings of the Society, each with four
sessions. A large amount of administrative business lias been done,
with earnestness and unity.

Meetings of the Society. — The records of the two meetings held during
the Year, at ( !olumbus and Rochester, will be found in full in the printed
proceedings of the Bulletin.

The attendance has been small, at Columbus twenty-three and at
Rochester thirty-four. The prosperity and success of the Society is,
however, not dependent upon the size of its meetings. The brief ex-
perience would seem to indicate that a larger attendance would he
secured at the great cities of the east, hut as an international society
it would not he proper to localize its sessions for the sake of larger
meetings.

Membership. — The Society has lost three Fellows during the year by
death: Dr-I.S. Newberry, Dr T. Sterry Hunt and Professor.!. H. Chapin-
Four names have been dropped, by application of the rules, for non-
payment of dues. The latest printed roll of membership bears the
names of 209 living and 9 deceased 1'ellows. At the summer meeting
L3 men were elected, of whom 12 have qualified, namely : A. E. Barlow,
Ei. P. H. Brumell, M. R. Campbell, A. del Castillo, II. W. Fairbanks,
L. S. Griswold, A. P. Low.V. F. Marsters, W. B Scott, C. H. Smyth, Jr.,

REPORT OF THE COUNCIL. 373

J. Stanley-Brown, ('. L. Whittle. From the list will be taken one name
by resignation and one for delinquency, leaving a total fellowship of 219.
Three elections arc announced at tins meeting: Professor H. F. Reidj
Mr. F. W. Sardeson and Mr J. F. Whiteaves.

Nine nominations are before the Council.

Aft r long and serious consideration the Council has determined not
to present any names for Correspondents at the present time.

Bulletin Publication. — Volume 3 has been distributed to all Fellows-
subscribers and exchanges direct from the Secretary's office. The cost
of the volume is given later in this report. The proceedings of the
summer meeting, making the first two brochures of volume 4, are
almost ready for distribution.

Bulletin Distribution. — The following tables show the distribution of the
three volumes. In explanation it should be said that the edition of
volume 1 was only five hundred copies, and that the first two volumes
were sent to the Fellows directly from the printers : also that the stock
ot volume 3 has not been wholly unpacked. It is found more convenient
to make the tables cover the whole distribution from the Secretary's office
during the past two years. A comparison of last year's report with this
will give the details for the past year.

Bulletin Distribution from tin Secretary's Offici During 1891 and 1892

BY COMPLETE Vol. I'M ES

Vol. 1. Vol.2. Vol.3.

In reserve 102 o4(i 395(?)

Donated to institutions (" exchanges ") 81 81 si

Held for "exchanges " 10 10 10

Si ild to Libraries, etc. . , 54 55 53

Sold to Fellows 11 9

Sent to Fellows to supply deficiencies 2 1

Donated by Council o .'! 1

Bound for office use 1 1 1

Sent to Fellows in brochures, as issued 209

Number of complete copies received 264 506 750(?)

BY BROCHI RES

Vol. 1. Vol. 2. Vol. :;.

| to 8 Fellows. . . . 39
Sent to Fellows to supply deficiencies. . - to 29 Fellows. ... 90

(to 7 Fellows.... 13

Sold to Fellows 5 :;

Sold to the public 2 4

(to '■• persons). ... 17

o/l PROCEEDINGS OF OTTAWA MEETING.

Bulletin Sales. — As announced by the Secretary, in January, a circular
letter advertising the Bulletin was sent to several hundred libraries in
the United States and Canada. Subscriptions have been received from
aboul thirty libraries, and a large number of irregular sales effected.
A set of books kept by the Secretary shows the details. The financial
result is given in the following tables:

.-■

Receipts from salt of Bulletin during is:i.'

BY SALE OF COMPLETE VOLUMES

Vol.1. Vol.2. Vol.3. Total.

From Fellows $14 50 $19 00 $4 50 $38 00

From libraries, etc. 170 00 175 00 142 00 487 00

Total $184 50 $194 00 $146 50 $525 I N I

By last report (1891) 115 10 102 50 217 60

Second total $299 60 $296 50 $146 50 $7 1 2 . I

BY SALE OF BROCHURES

Vol. 1.

From Fellows

From the public $1 40

Vol. 2.

Vol. 3.

Total.

$0 50

$0 50

GO

$2 65

4 65

Total $140 $110 $2 65 $5 15

By last report (1891) 3 15 4 95 8 10

Second total $4 55 $6 05 $2 65 $13 25

Grand total $755 85

Received for volume 4, in advance 15 00

Receipts to date $770 85

Amount uncollected 170 45

Bulletin sales to date $941 30

"Exchanges." — The list of institutions to which the Bulletin is donated
is not materially different from that of the last report. Seventy-nine
institutions have been placed on. the list.

Library. — The material received in return tor the Bulletin, mostly from
foreign societies, makes about 100 volumes, entire or fractional. This is
chiefly geological matter and should be u<vi\\\ to the Fellows as soon as
it can be made accessible. The Council has not yet acted under thi

REPORT OF THE COUNCIL. 375

authority conferred at the last annual meeting, empowering it to select
a depository for this accumulating material, hut the matter is in the
hands of a committee and such selection will probably soon be made.

The matter collected by Professor Hitchcock is as follows :

A complete set of the Reports of the Second Geological Survey of
Pennsylvania, 115 volumes and several elephant folio atlases.

Reports of the Geological Surveys of other States as follows: Illinois,
8 volumes; Ohio, 8 volumes; Arkansas, 7 volumes; Texas, 2 volumes;
California, 9 volumes and pamphlets.

Tenth Annual Report of the U. S. Geological Survey, and Bulletins
G2-81.

Miscellaneous hooks, 15; pamphlets, '225, largely authors' copies, es-
pecially of the younger Fellows. Several lists of publications of indi-
vidual Fellows.

A few volumes from exchanges, and about 30 duplicates.

The number of contributors. 36.

Photographs of 35 Fellow-.

Two large maps of the United States, made for the Society. Crayon
portrait of Alexander Winched .

Finances. — Following is a summary of the finances of the past year,
the details being given in the Treasurer's Report :

Receipts from all sources, 83,010.52, made up of the following items :

Fellowship fees $2,180 00

Life commutations 100 00

Interest and investments 102 7o

Sales of Bulletin 426 85

Repayments on rust of Bulletin 200 94

3,01(1 52
Balance from former Treasurer L,258 95

Total $4,269 47

EXPENDITURES DURING THE VKAl;

Publication of Bulletin $1,667 68

Maps and photographs 43 83

Administration (including Bulletin distribution] 467 91

Investments • 1,488 90

Total $3,668 32

Balance in Treasury ' 601 L5

$4,269 17

3/6 PROCEEDINGS OF OTTAWA MEETING.

The cost of volumes 1, 2 and -'J of the Bulletin is shown in the follow-
ing tabulation :

COST OF BULLETIN

Vol. I. Vol. 2. Vol. ::.

(pp. 593; pi. 13.) (PP.662; pi. 23.) (pp.541 : pi. 17.)

( !osl to the Si iciety :

Letterpress $1,367 77 $1,935 27 $1,439 00

Illustrations 29185 302 35 26160

Total $1,659 62 $2,237 62 $1,700 60

( !osl to authors :*

Letter-press $79 59

Illustrations $161 30 121 75

Corrections $38 00 27 25 5 00

Brochure covers. . 68 00 30 00 12 00

Total $106 00 $218 55 $218 34

Aggregate $1,765 62 $2,456 17 $1,918 94

Respectfully submitted,

The Council.

The Treasurer, I. C. White, read his annual report, as follows:

REPORT OF THE TREASURER

Report of the Treasurer of the Geological Society of Ann rim fur the Year end-
ing Novt mb&r ■>'". 1892

The Treasurer, in submitting his financial report, would recommend
that the By-laws of the Society be amended so that the Life Commuta-
tions shall go immediately into the Publication Fund. This would
simplify the accounts and save the Treasurer considerable unnecessary
work.

The detailed operations of the Treasury are shown by the following
financial statement to December 1, 1892:

* Including, for volume 3, donations of printing and engraving by I. C. White, $111.09, and en-
graving by N. H. Winchell, $9.00; an aggregate of $120.09.

REPORT OF THE TREASURER.

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378 PROCEEDINGS OF OTTAWA MEETING.

The Society elected as a committee to audit the Treasurer's accounts
Robert Bell and R. D. Salisbury.

ELECTION OF OFFICERS FOB 1 893

The result of the balloting for officers for 1893, as canvassed by the
Council, was declared as follows:

Presidi
Sir J. William Dawson, Montreal, Canada.

/'.' -j Vice-president :
T. ('. Chamberlin, Chicago, 111.

■< tary:

11. 1.. F MK.iiii.D. Rochester, X. V.

I. ('. White, Morgantown, W. Va.

No candidate for the offices of Second Vice-president, Councillors and
Editor having a majority of all the ballots cast, the election of such
officers under the rules was made by ballot, in the meeting, from the two
candidates having the greatest number of votes for the respective offices.
The President named as tellers for the balloting F. D. Adams and R.
W. Ells. The balloting was separately tor each office, and resulted as
follows :

5 iiiid Via -presidi nt :

.1. .1. Stevenson, New York city.

( uncillors :
F. A. Smith. Tuscaloosa, Ala.
C. D. Walcott, Washington, l>. C.

Editor:
•I. Stanley-Brown, Washington, D. C.

ELECTION OF FELLOWS

The result of the balloting tor Fellow-, as canvassed by the Council,
was declared as follows :

FF.LI.oWs ELECTED

Harry Fielding Reid, Ph. !>.. Cleveland, <>hi<>. Professor of Physics in Case

School Of Applied Science.

I:. PUMPELLY — MEMORIAL OF T. STERRY HUNT. 379

Frederick William Sardeson, Minneapolis, Minnesota, Post-graduate in ( feology.

Now engaged in paleozoic paleontology.
Joseph Frederick Whiteaves, Ottawa, Canada. Paleontologisl and Assistanl

Director of the Geologi* 1 Survey of Canada. Working on Canadian paleon-

toloj

A memorial of T. Sterry Hunt, in the absence of the author, was
read by < '. I!. Van I [ise.

MEMORIAL OF THOMAS STERRY IM VI
l: , RAPHAEL PUMPELLY

Thomas St< rry Hunt was !>'>ni in Norwich, Connecticut, September 5,
1826, and died in New York February 12, L892. Hi- intimate friend,
James Douglass, has drawn with a loving hand a sketch of his life,
fromwhich I have taken freely the details of hi y years * He came

of Puritan stock, including oh his mother's side the mystic Peter Sterry
and the preacher, Thoma ry, author of a notable tract, " The Rol

among the Bishops," in 1667, in England, and ' ionsider and John Sterry,
mathematicians in New England. For a shorl period only he att< nded
the public school, and then, to aid in the support of his widowed mother
and her family, he worked successively, a few months in each, in a
printing office, an apothecary's shop, and a bookstore, and later in a
country store. Bent on studying medicine, he kepi a skeleton and
home-made chemical apparatus under the counter, using the stove for a
furnace. Mr Douglas 3ays thai with this equiprnenl he made investiga-
tions into the properties of hydriodic acid, anticipating to a certain
extent those of Deville. During a trip to New Haven, in 1845, al the
meeting of the Association of Naturalists and Geologists he acted as
reporter for a New York paper. Here he attracted the attention of the
elder Silliman, who facilitated his admission into Yale, made him hie
assistanl in water analyses, and took him into his household. This was
the greal turning point of his life and doubtless determined his chem-
ical and mineralogical career, ruder happy auspices while al Yi
between his eighteenth and tw< i year, he contributed eighteen

papers to Silliman's Journal and wrote the Organic Chemistry for Silli-
maivs First Principles.

At twenty years of age, in 1847, he became Chemisi and Mineralogist
to the ( leological Survey of Canada, a connection which he retained' till
1872. The Canadian Survey had largely to do with a greal developm<
of crystaljim and with varied mineral resources. Hunt threw his

energies into the work before him and, single-handed, worked oul th

as. Amer. Inst. Min. Eng., I

LVII— Bi i ■ '■ >>r., Vol. ). 1892.

380 PROCEEDINGS OF OTTAWA MEETING.

chemical and mineralogical details of the economic geology of a vasl re-
gion, and supplied to a great extent the Lithological basis for a classifica-
tion of its rocks. At the same time he was developing a system ofchemic
geology based very largely on his own original investigations. Logan and
1 1 11 1 it soon supplemented each the other— the one an excellent geologist,
with a wide and growing field experience; the other an able chemist and
mineralogist, with a versatile and suggestive mind. Both profited by
this combination, which contributed greatly to the successful prosecu-
tion of the Survey. During- this period he also occupied the chair of
chemistry at the Laval University, at Quebec, from 1856 to 1862 and at
McGill University, Montreal, from 1862 to 1868.

From 1S72 to 1878 he was Professor of Geology at the Massachusetts
Institute of Technology. He was a juror at the Paris Expositions in
185(3 and 1857, and there came into personal contact with the geologists
of England and the continent. In 1859 he was elected a Fellow of the
Royal Society of London, and a member of the National Academy of
Sciences in 1873. In 1S81 the University of Cambridge conferred on him
the degree of LL. D. . He was acting President of the American Asso-
ciation for the Advancement of Science in 1871, President in 1877 of the
Institute of Mining Engineers, and the first elected President of the
Royal Society oi Canada. It is to his motion, made to the American
Association for the Advancement of Science in 1876, that we owe the
plan for an International Geological Congress, and he held office at sev-
eral of the meetings of this body. In 1855 the French government
made him a Chevalier of the Legion of Plonor. and later an officer of the
~ame order, and after the Bologna meeting of the Geological Congress
he received the order of Saint Mauritius and of Saint Lazarus.

Dr Hunt was a most indefatigable worker and reader of a wide range
of literature, and seems to have had a wonderfully retentive memory.
In s] .caking, his addresses and papers were given without notes and were
remarkable for their ready fluency and directness of diction, as veil as
for logical arrangement of ideas. The number of his published contribu-
tions to scientific literature is very large, but the more important part of
his work is embodied in the few volumes which he published: " Chemical
and Geological Essays," 1874 and 1878; "Azoic Pocks," 1878 : "Mineral
Physiology and Physiography," 1886; "A New Basis for Chemistry."
L887, and " Mineralogy according to a Natural System." 1891.

Mr Douglas informs us that Dr Hunt was a good mathematician and
had an excellent acquaintance with botany, in which his interest lay
more, however, on the esthetic and economic than on the purely sys-
tematic side. 1 le acquired such a knowledge of Drench as enabled him
to speak it equally fluently with English. Indeed, he was a remarkable

K. PUMPELLY — MEMORIAL OP T. STERRY HUNT. 381

instance of self-developed genius, for lie had a brief and imperfect public-
school education and less than two years in Yale, where most of his time
must have been spent in work as an assistant.

It is as an honored member of our Society and as a geologist that we
have to speak of him on this occasion, and it is therefore fitting that wc
dwell particularly on those of his contributions to geology which mark
his position in the history of the science and which also explain his in-
dividual attitude toward some of its more important problems.

His work in mineral chemistry and in the analyses of rocks led him
naturally to the lithological side of geology. The logical and speculative
nature of his mind impelled him to attempt the discovery of a general
law underlying the origin of the crystalline rocks, both massive and
schistose. He began in 1858 with the conception of a solid incandescent
globe, which, at least in the outer layer, was an undifferentiated quartz-
less basic silicate, approximating dolorite in composition. At this start-
ing point, while this mass contained all the non-volatile elements, the
atmosphere still contained all the volatile elements, being densely charged
with all the carbon, sulphur and chlorine, combined with oxygen or
hydrogen, and containing watery vapor, nitrogen and a probable excess
of oxygen. He considered that in the condensation of this atmosphere
and the reaction of its powerful solvents upon the undifferentiated basic
rock lay the key to the genesis of the crystalline rocks. The sulphur
and chlorine of the condensing atmosphere combined with the protoxide
bases of the rock and went to form the sulphates and chlorides of the
ocean and to neutralize its waters. In the waters permeating the rock
heated from below an active circulation was established, thus bringing
to the surface the matters to be deposited.

Through this upward lixiviation the primary undifferentiated rock
was separated into an upper acidic layer, chiefly of acid silicates, as
feldspars with quartz, and a lower residuary basic and insoluble mass
charged with iron and magnesium, the two representing the overlying
granitic and the underlying basaltic layers required by many geologists.
To this explanation he gave the name of Crenitic Hypothesis In the
shrinkage of the great thickness, made porous by the lixiviation, he
found the cause of the corrugation of the crystalline rocks and of the
accompanying early extravasation of basic rocks. The lixiviation or
crenitic portion of this hypothesis was not announced till 1884. In its
earlier stages its author conceived the primal undifferentiated rock of
the early globe to be everywhere deeply buried under its ruins — under
a great thickness of fine and coarse sediments produced by the first tie-
composition of the rock by acid waters and by extensive subaerial decay,
permeated by infiltrating waters and heated from below. Through the

382 PROCEEDINGS OF OTTAWA MEETING.

circulation of these waters he imagined these cletrital accumulations to
have been differentiated into two great divisions, the one having an
excess of silica, a predominance of potash and small amounts of lime,
magnesia and soda, represented by the granites and trachytes ; the other,
having less silica and potash, and prevalence of soda, lime and magnesia,
giving vise to pyroxene and triclinic feldspars. In the metamorphism
and displacement of these differentiated sediments he explained the
origin of the plutonic rocks. At this period he was a believer in the
metamorphic origin of the crystalline rocks, holding with Keferstein
"that all the unstratiiied rocks from granite to lava are products of the
transformation of sedimentary strata, in part very recent." l'.ut the inti-
mate relation, required by his growing hypothesis, between this meta-
morphism and the chemical processes acting upon a recently solidified
globe, seem to have soon caused him to reject the possibility of the for-
mation of crystalline rocks by metamorphic processes acting upon sedi-
ments of later than pre-Cambrian age; for, in the final formulation of
the crenitic hypothesis, he states that the products of subaerial decay
(both of the crenitic rocks and of the basic rocks erupted from the
underlying residual primary basic mass), reacted upon by the materials
brought up by the crenitic processes, contributed to the formation of the
transition crystalline schist, and in the transition or pre-Cambrian schists
he saw only the relatively feeble and dying-out action of the crenitic
processes.

It was a natural consequence of this attitude that Dr Hunt took an
active part in the " Taconic Controversy " and ranged himself on the
side which claimed a pre-Cambrian age for the quartzite limestone and
schist series of the great Appalachian valley called Lower Taconic by
Emmons and Taconian by Hunt. He had thought out a, system which
premises that ''the laws which have presided over the differentiation of
the primeval chaos and produced the various groups of rocks, * * :;:
which have determined the progressive changes in chemical constitution
from the anti-gneissic granite down to the youngest crystalline schists
and the detrital sediments of later times, are * * * not less cer-
tain and definite than those which preside over astronomical and bio-
logical development." He insists that '•the great successive groups of
stratiform crystalline rocks mark necessary stages in the mineralogical
evolution of the planet.'1

Acting upon this idea, he divided the crystalline-rock-making time
into six periods :

I.' Laurentian — granite and gneiss — during which the lixiviating
process brought up acid silicates and quartz; the presence of lime-
stones in supposed Laurentian rocks being due to a reaction of the
crenitic lime silicates.

R. PUMPELLY — MEMORIAL OV T. STEKKY HUNT. 383

II. Norian, the formation of which was only possible after the crenitic
lixiviation had exhausted a large part of the accessible primary mass of
much of its silica in the forms of orthoclase albite and quartz, so that
the succeeding secretions furnished the less acid silicates, as labradorite
and andesite.

III. Arvonian; a stratified scries of rocks including petrosilex, and
quartziferous porphyry associated with beds of quartzite, micaceous
schists, great beds of hematite and more rarely layers of crystalline
limestone. This series he places between the Laurentian and the
Huronian, stating that he is unable to fix its exact relation to the
Norian.

IV. Huronian. — The shrinkage originating in the removal from the
primary mass of the material to form the preceding three series caused
eruptions from the underlying basic mass, so that extensive areas, both
of the crenitic acid rocks and of the eruptive basic rocks, were exposed
to subaerial decay.

In this decay the acid crenitic rocks gave up their alkalies, leaving
residual clays, while the basic rocks yielded their lime and magnesia.
The alkaline and magnesian carbonates introduced a new factor into the
history of the rocks, for, reacting upon the calcium-chloride of the
primeval sea, this produced Lime, carbonate and alkaline and magnesian
chlorides. Thus a magnesian sea was formed. The reaction of the
magnesian salts of this sea upon the petrolitic matters (lime silicates) of
the continued crenitic secretions brought into the sediments a vast
amount of magnesian silicates, giving a distinctive character and color
to the resulting schists.

V. Montalban. — The Huronian required for its formation a magnesian
sea, caused by the subaerial decay of both crenitic and especially of
eruptive basic rocks on one hand, and by the continued addition of
crenitic lime-silicate secretions contributed in an advanced stage of
lixiviation on the other. The building up of the Montalban series of
fine-grained gneisses, granulites, mica-schists and schists abounding in
aluminous silicates of the Andalusite type presupposes the comparative
absence of magnesium from the seas. Here the gneisses are of purely
crenitic origin, and the schists are derived mainly from the products of
subaerial decay of the older crenitic rocks, the resulting clays, still car-
rying a portion of their alkali, with or without the aid of crenitic secre-
tions, yielded by diagenesis, muscovite, quartz and the simple aluminous
silicates.

VI. Taconian. — This great series of quartzites, limestones, hydromica-
schists and argillites, according to Dr Hunt, marks a stage of diminished
energy in the process. In the schists he sees apparently the products

384 PROCEEDINGS OF OTTAWA MEETING.

of subaerial decay < >f the older crenitic rocka subjected to diagenesis, and
in the presence of certain "apparently feldspathic matters forming im-
perfed gneisses" evidence of the still, though feebly acting, crenitic
process. Traces of the still later and more feeble remnant of the crenitic
process arc found by J >r Hunt in the presence of rutile, tourmaline and
staurolite and in the paleozoic argillites.

Having stated this order of development as an inflexible law, he as-
signed all the rocks generally called plutonic and metamorphic, respect-
ively to these periods, thus forming an interdependent chronologic and
Lithologic canon. In this light it is easy to understand his reasons lor
denying the formation of crystalline schists during later periods than
the pre-Cambrian, and also lor rejecting a recognition of those process -
which, like pseudo morphism, metasomatosis, etc, have been used in ex-
plaining local and regional metamorphism.

The so-called Taconic rocks had been by many of the most eminent
geologists placed in the Paleozoic, a view which he held in common with
Logan as late as 1868, and which was reiterated later by Dana after an
extended and careful field study. Many of these rocks are highly crys-
talline and include gneisses. This touched a critical point in Dr Hunt's
system at a later period of it- growth, ami he was naturally drawn into
the Taconic controversy. The structural and other problems underlying
this long and bitterly contested question were extremely complicated
and such that the correctness of any interpretation could he ascertained
only by exceedingly detailed surveys, made with such topographic maps
as did not then exist. It should not he counted against Dr Hunt that
from the limited reconnaissance field-work which he was able to do, he
came out a partisan for any particular side. But, considering the vari-
ous possible interpretations of the facts, his interpretation was naturally
one in agreement with the requirements of his law of development oi
crystalline rocks. Thus in this controversy he held the view that the
series called Lower Taconic by Emmons is of pre-Cambrian age. This
series he named Taconian. In so far as western New England is con-
cerned, it consists of the Stockbridge lime-tone with its underlying quartz-
ite and overlying hydromica-schists, and has been recently shown by the
stratigraphical studies of Dana, Wolff, Putnam. Dale, Hobbs and the
writer, aided by the paleontological work of Wing, Walcott, Foerste,
Wolff and Dale, to range probably in unbroken succession from the
Olenellus Cambrian to the Hudson Liver group. At the top of this
series he drew a great time-break, and placed above it Emmons3 Upper
Taconic, and assigned it to the Lower and .Middle Cambrian.

A review of his recorded work shows that he was a brilliant and origi-
nal thinker, and that his speculations in chemical geology were based on

BIBLIOGRAPHY OF T. STERRY HUNT. 3S5

a large amount of original laboratory research and on a skillful use of
that of others. Such a review brings out to light also a laek of that ex-
perience in detailed field-work, both original and critical, especially in
structural geology, which is essential in building hypotheses and in test-
ing them step by step. One cannot but feel that he was seriously limited
by this deficiency, and that this limitation caused him to continue
through the world's half century of progress in geology to construct a
history of the early globe on a plan circumscribed by conceptions formed
early in his career. Throughout his time he was the leading representa-
tive of chemical geology in America, and his works contain, both on the
side of original research and of speculation, very much of the material
necessary to construct the same history on lines more in accord with the
present requirements. On its suggestive side Dr Hunt's work in chemical
geology has ranked high in both hemispheres and its influence will long-
continue to be felt, and in a growing science this is perhaps the rarest
and most important side.

The following bibliography indicates in the most graphic manner the
enormous amount of work performed by Dr Hunt during his scientific
career :

BIBLIOGRAPHY.

Some Ores and mineral Waters: Rep. Canadian Geol. Survey, 1845.

Description and Analysis of various Minerals, Ores and mineral Waters: Rep.
< 'a undid n Geol. Survey, 1S47.

Examinations of various Minerals and mineral Springs: Rep. < '<tn>t<li<ni Geol. Sur-
vey, 1848.

Analyses of various Soils, mineral Waters and Ores: Rep. Canadian Geol. Sunn/,
1849.

Examinations of various Minerals and mineral Waters: Rep. Canadian Geol. Sur-
vi y, 1850.

Analyses of Rocks, Soils, Minerals and mineral Waters: Rep. Canadian Geol. Sur-
vey, 1851.

On the Taconic System: Proc Am. Assoc. Adv. Sci., vol. iv, 1850, p. 202.

On the mineral Springs of Canada: Am. Jour. Sci., vol. xi, 1851, p. 174.

(>n some Canadian Minerals: /,., /•;. and I). Philosophical Magazine, April, 1851, pp.
322-328.

On Loganite, a new Mineral : L., E. and D. Philosophical Magazine, Julv, L851, pp.
65-07.

Classification and Analysis of mineral Waters, with Examination of various Min-
erals and Ores: Rep. Canadian Geol. Survey, L852.

Examination of some American .Minerals: Am. Jour. Sci., vol. xiv, 1852, pp. 340-
:;4fi.

On the Constitution and equivalent Volume of some mineral Species: .1///. Jour.

Sri., vol. xiv, is.-):;, pp. 203-218.
On mineral Waters of Canada: J,',}!. Canadian Geol. Survey, L853, pp. 347-365.

386 PROCEEDINGS OF OTTAWA MEETING.

Limestone and Dolomite: Rep. Canadian Geol. Survey, 1853, pp. 366

Tlic Theory of chemical Changes and equivalent Volume: Am. Jour. ScL, March,

L853, p. 226; L., /■.'. and D. Philosophical Magazine, vol. v, 1853, pp. 526-535;

Chemisches Central Blatt, 1853, p. 849.

< in someof the crystalline Limestones of North America (abstract) : Am. Joui . §

vol. xviii. L854, pp. 193-200.
Triclinic Feldspars of the Laurentian Series: Rep. Canadian Geol. Survey, 1854,

pp. 373-383.
Silurian Rock>. Ores of Nickel, etc: Rep. Canadian G :. Survey, 1854, pp. 383-390.
Metallurgy of Iron and iron Ores of Sweden, Russia and of Canada : Rep. Canadian

Geol. Survey, L855, pp. 391^04.
Extraction of Sail from Sea-water: Rep. Canadian Geol. Survey, 1855, pp. 401-418.
Magnesian Mortars: Rep. Canadian Geol. Survey, 1855, pp. 419-423.
<>n Plumbago and it.- Purification: Rep. Canadian Geol. Survey, 1855, pp. 423-425.

< in Peat, and Products derived from it: Rep. Canadian Geol. Survey, 1855, pp. 125-

4l". i.
Dolomites and fish Manures : Rep. Canadian G - . 1857, pp. 193-229.
On the probable Origin of some magnesian Rocks: Am. Jour. Sri., vol. xxiv. 1857,

pp. 272, 273.
Intrusive Rocks: Rep. Canadian Geol. Survey, \<^. pp. 171-188.
Intrusive Rocks of Grenville : Rep. Canadian Geol. Survey, 1858, pp. 193-197.
Minerals from Silurian Rocks: Rep. Canadian Geol. Survey, 1857, pp. 193-197.
Contribution to the History of Magnesian Limestone: /.'■/<. Canadian Geol. Su

1858, pp. 197-218.
Examination of some feldspathic Rocks: /,.. E. and I>. Philosophical Magazine,

May. 1855.
On the so-called talcose Slates of the Green Mountains: Am. Jour. Sci., vol. xix.

L855, p. 417.
Parallelism of the Metamorphic Eocks : /.'•/<. Canadian Geol. Survey, 1856, pp. 431,

432.
Silurian Series : Rep. Canadian Geol. Survey, 1856, pp. 432-480.
Laurentian Series: 11, p. Canadian Geol. Sur ey, 1856, pp. 480-485.
Igneous Rocks: Rep. Canadian Geol. Survey, 1856, pp. 4s.o-494.
On the Chemistry of the primeval Earth (letter to Professor J. D. Dana): Am.

Jour. S I, vol. xxv. 1858, pp. 102. 10
Contributions to the History of Ophiolites, part I: Am. Jour. ScL, vol. xxv. 1858,

pp. 217-221,.
On the Extraction of Salts from Sea-water: Am. Jour. Sci., vol. xxv. 1858, pp.

361-371.
On the Origin of Feldspars, and on some Points of chemical Lithology : Am. Jour.

Sci., vol. xxv. 1858, pp. 435-4:17.
On Euphotide and Saussurite: Am. Jour. Sci., vol. xxv, 1858, p. 437.
Contributions to the History of Ophiolites, part II: Am.J<mr. Sci., vol. xxvi. 1858,

pp. 2: '.4-240.
A Theory of igneous Rock- and Volcanoes: Toronto, L858.
On the Extraction of Salts from Sea-water: Canadian Naturalist, vol. iii, 1858,

pp. 97-101.
On the Theory of igneous Rocks and Volcanoes Canadian Naturalist, vol. iii. 1858,

pp. 194-201.

BIBLIOGRAPHY OF T. STKRRY HUNT. 387

Fish Manures: Canadian Naturalist, vol. iv,- 1859, pp. 13-23.
Some Points in Chemical Geology: Quar. Geological Jour., November, 1859.
On some Reactions of the Salts of Lime and Magnesia, and on the Formation of
Gypsums and magnesian Rocks: .1/;/. Jour. Sri., vol. xxviii, 1S59, pp. 170-187
and 365-383.
On some Points in chemical Geology: Canadian Naturalist, vol. iv, 1859, pp.

414-425.
( >n some Points in the Geology of the Alps (a review of " Memoire sur les terrains
liassique et Keuperien de la Savoie, par Alphonse Favre"): Am. Jour. Sri.,
vol. xxix, 1860, pp. 118-124.
Notes on the Dolomites of the Paris Basin: Am. Jour. Sri., vol. xxix, 1860, p. 284.
On some of the igneous Rocks of Canada : Am. Jour. Sri., vol. xxix, 18(30, p. 282.
On some Points in American Geology : Am. Jour. Sci., vol. xxxi, 1861, pp. 392 414

Reprinted in Canadian Naturalist, vol. vi, 1861, pp. 81-105.
Note on Chlorotoid from Canada: Am. Jour. Sci., vol. xxxi, 1861, pp. 442-443.
( reological Survey of Canada (a review) : Am. Jour. Sci., vol. xxxi. 1861, pp. 122-

124.
< m the < >rigin of some magnesian and aluminous Rocks : Am. Jour. Sri., vol. xxxii,

1861, pp. 286-288; see also Canadian Naturalist, vol. vi, 1861, pp. 180-184.
On the Taconic System of Dr Emmons: Am. Jour. Sri., vol. xxxii, 1861, pp. 427-

430. and vol. xxxiii. 1862, pp. 135-136.
On the Unity of geological Phenomena in the Solar System, by L. Saemann
(translated by T. Sterry Hunt) : Canadian Naturalist, vol. vi, 1861, pp. 444-451.
Mr Barrandeon the Primordial Zone in North America, and on the Taconic System

of Emmons: Canadian Naturalist, vol. vi, 1861, pp. 374-383.
Notes on the History of Petroleum or Rock-oil: Canadian Naturalist, vol. vi, 1861,

pp. 241-255.
Note on the Taconic System of Emmons: Canadian Naturalist, vol. vii, 1862, pp.

78-80.
Note on Gabbro: Canadian Naturalist, vol. vii. 1862, p. 17.

On the Chemistry of the Earth (extract from a letter to Elie de Beaumont, pub-
lished in Comptes Rendues de L'Acad. de Sci. de France, June 9, 1862): Cana-
dian Naturalist, vol. vii, 1862, pp. 201-205.
Note on Naumann's Paper on primitive Formations: Canadian Naturalist, vol. vii,

L862, pp. 262-263.
Considerations sur la Chimie du < rlobe. Lettre de M. J. Sterry Hunt a M. Elie de

Beaumonl : Comptes Rendues de VAcad. d\ Sri. de From; , 1 i v, 9 Juni L862.
Contributions to the chemical and geological History of Bitumens, and of Pyro-

schists or bituminous Shales : Am. -lour. Sri., vol. xxxv, L863, pp. 157-171.
On the chemical and mineralogical Relations of metamorphic Rocks: Am. Jour.
Sri., vol. xxxvi, 1863, pp. 214-22H; see also Canadian Naturalist, vol. viii, 1863,
pp. 195-208.
On the earth's Climate in Paleozoic Times : Am. Jour. Sci., vol. xxxvi, 1863, pp.

396-398; see also Canadian Naturalist, vol. viii, 1863, pp. 323-325.
On the Nature of Jade, and on a ne^ mineral Species described by Mr Damour
(Comptes Rendues, French Acad. Sci., June 29, 1863).: Am. Jour. Sri., vol.
xxxvi. L863, pp. 426-428.
Sur la Nature du Jade : Comptes Rendues dt VAcad. d> s,-;. <i, Fvance, lvi, 29 Juni
L863, p. 1255.

LVIII-Bull. Geoi,. Soc. Am., Vol. <1, 1892.

388 PROCEEDINGS OF OTTAWA MEETING.

The Chemistry of metamorphic Rocks: Dublin Quarterly Jour., July, 1863.
On the gold Mines of Canada, and the Manner of working them: Canadian Natu-
ralist, vol. viii, L863, pp. 13-19.
Mineral Species: Rep. Canadian Geol. Survey, chap, xvii, 1863, pp. 454-530.
Waters of mineral Springs and of Rivers: Rep. Canadian Geol. Survey, chap, xviii

1863, pp. 531-568.
On sedimentary and metamorphic Rocks: Rep. Canadian Geol. Survey, chap, xix,

L863, pp. 569-642.
Eruptive Rocks: Rep. Canadian Geol. Survey, chap, xx, 1863, pp. 643-670.
Economic Geology : Rep. Canadian Geol. Survey, chap, xxi, 1803, pp. 071-835.
Contributions to Lithology: Am. Jour. Sci.,\o\. xxxvii, 1864, pp. 248-266; vol.

xxxviii, 1864, pp. 91-104 and 1 74-1 sr> ; see also Canadian Naturalist, second

ser., vol. i, 1864, pp. L6-36 and 161-189.
Contributions to Lithology, 1864, 51 pages.

On Peat and its Uses: Cauailiau Naturally/, second ser., vol. i, 1864, pp. 426 441.
Notes on the Silicification of Fossils: Canadian Naturalist, vol. i, 1864, pp. 4(1-50.
Contributions to the Chemistry of natural Waters: Am. Jour. Sci., vol. xxxix,

1865, pp. 176-193; vol. xl, 1865, pp. 43-60 and 11)3-213; see also Canadian Nat-
uralist, second ser., vol. ii, 1865, pp. 1-21; 161-183; 276-299.
Laurentian Rhizopods of Canada: Am. Jour. Sri., vol. xxxvii, 1864, p. 431, and

also vol. xl, 1865, p. 344.
A Geographical Sketch of Canada : Canadian Naturalist, vol. ii, 1865, pp. 356-303.
On the Mineralogy of Eozo'dn Canadense: Cauailiau Naturalist, second ser., vol. ii,

1865, pp. 120-127.
On the Objects and Method of Mineralogy: Canadian Naturalist, second ser., vol.

iii, L866, pp. 110-114; see also Am. Jour. Sci., vol. xliii, 1807, pp. 203-200.
On the Laurentian Limestones and their Mineralogy (ahstract) : Proc. Am. Assoc.

Adv. Sri., 1800, pp. 54r57.
Assays of Quartz for Gold: Rep. Cauailiau Geol. Surrey, I860, pp. 79-90.
Geology and Mineralogy of Laurentian Limestone: Rep. Cauailiau Geol. Survey,

1 Si ill, pp. 181-232.
Geology of Petroleum : Rep. Cauailiau Geol. Survey, 1800, pp. 233-202.
Brine Springs and Salt: Rep. Cauailiau Geol. Survey, 1800. pp. 203-280.
On the Porosity of Rocks: Rep. Cauailiau Geol. Survey, 1800, pp. 281-284.
Peat and its Applications: Rep. Cauailiau Geol. Survey, 1866, pp. 284-291.
Further Contributions to the History of lime and magnesia Salts: Am. Jour. Sci.,

vol. xlii, 1800, pp. 49-07.
On the Chemistry of the primeval Earth: Cauailiau Naturalist, second ser., vol.

iii, 1807, pp. 225-234; see also Notices Proc. Roy. Inst. Great Britain, vol. v,

1807, p. 178; Chemical News, June 21, 1807; and Smithsonian Report, 1809.
On the general metallurgical Method of Messrs. Whelpley and Storer: Am. Jour.

Sri., vol. xliii, 1807, pp. 305-309.
Report on the gold Regions of the County of Hastings (Dr Hunt and Mr Michel) :

1867, II pages.
Geological Details of the Goderich sail Region: /.'<//. Canadian Geol. Survey, 1807,

"08 and '09, pp. 211-244.
Iron and iron Ores: Rep. Canadian Geol. Survey, 1807, '68 and '69, pp. 245-304.
Reporl on the -old lie-ions of Nova Scotia (Dr Hunt and Mr Michel): 1868,48

pages.

BIBLIOGKAPHY OF T. STEKKV HUNT. 389

On some Points in the Geology of Vermont: Am. Jour. Sci., vol. xlvi, L868, pp.

222-229.
Notes on the Geology of southwestern Ontario : Am. .lour. Sci., vol. xlvi, 1868, pp.

355-362.
On the probable seat of volcanic Action : Geological Magazine, June, L869 ; see also

Canadian Naturalist, second ser., vol. iv, 1869, pp. 1 (>(i— 1 7.'j, and .1///. Jour. Sci.,

vol. 1, July, 1870, pp. 21-28.
Analyses of silver Ore, Coal, etc: Rrp. Canadian Geol. Survey, L870, pp. (>(>, 67.
Notes on granitic Rocks, part I: Canadian Naturalist, second ser., vol. v, 1870,

pp. 338-406; part II: Am. Jour. Sci., February and March, L871, pp. 82 89

and 182-191 ; part III: Am. Jour. Sci., vol. iii, L872, pp. 115-125.
On the Geology of eastern New England: Am. Jour. Sci., vol. I, July 1870,|pp. 83-

90; see also Canadian Naturalist, second ser., vol. v, L870, pp. 198-205.
On Astronomy and Geology: Canadian Naturalist, second ser., vol. v, 1870, pp.

-160-462.
On the Laurentian Rocks in eastern Massachusetts: Am. Jour. Sci., vol. xlix, Jan-
uary, 1870, pp. 75-78; and also Canadian Naturalist, second ser., vol. v, 1870,

pp. 7-10.
On the Geology of the Vicinity of Boston: I'roc. Boston Sdc. Nut. Hist., vol. xiv,

October 19, 1870, pp. 45-49.
On Laurentian Rocks in Nova Scotia : .1//*. Jour. Sci., vol. 1, 1870, pp. 132-134.
On norite or labradorite Rock : .1///. Jour. Sci., vol. xlix, L870, pp. 180-186; sec

also Canadian Xuluralist, second ser., vol. v, 1870, pp. 31-38.
Labradorite Rocks at Marblehead : .1///. Jour. Sri., vol. xlix, 1870, p. 398.
Contributions to the Chemistry of Copper: Am. ./our. Sci., vol. xlix, 1870, pp.

153-157.
Presidential Address: l'roc. Am. Assoc. Adv. Sci., 1871, pp. 1-59.
Review of Hart's Geology of Brazil : The. Nation, December 1, 1870.
On a mineral Silicate injecting Paleozoic Crinoids : Am. Jour. Sri., vol. i, 1871, pp.

379-380.
On the oil-bearing Limestone of Chicago : .1//;. ./our. Sci., vol. i, 1871, pp. 420-421 ;

see also Canadian Naturalist, second ser., vol. vi, 1872, pp. 54-59.
.Mineral Silicates in Fossils: Am. .lour. Sri., vol. ii, 1871, pp. £7, 58.
On the Oil-wells of Terre Haute, Indiana (abstract by author) : Am. Jour. Sci.

vol. ii, 1871, pp. 369-371.
History of the Names Cambrian and Silurian in Geology: Canadian Naturalist,

second ser., vol. vi, 1872, pp. 281-31 1 and 417-448; reviewed in Am. ./our. Sri..

vol. iv, L872, pp. 41(i-417.
Remarks on the Hunt and Douglas copper Process: Trans. Am. Inst. Min. Engineers,

vol. i, 1871', pp. 258-260.
On the Theory of Volcanoes: Proc. Boston Sue. Nat. Hist., vol. xv, November 6,

1872, pp. 250-252.

On alpine Geology : Am. Jour. Sri., vol. iii, 1872, pp. 1-1.").

Remarks on the Criticisms of Professor Dana: Am. Jour. Sri., vol. iv, 1872, pp.

41-52.
The geognostical History of the Metals: Trans. Am. Inst. Min. Engineers, vol. i,

1873, pp. 3:; 1-342.

Remarks on an Occurrence of Tin-ore at Winslow, Maine: Trans, Am. lust. Min,
Engineers, vol. i, 1873, pp. 373, 374.

300 PROCEEDINGS OF OTTAWA MEETING.

The Origin of metalliferous Deposits : Trans. Am. Tnst. Min. Engineers, vol. i. L873,

pp. 413-426.
Supplementary Note on the Geology of the north Shore of Lake Superior : Trans.

Am. Inst. Min. Engineers, vol. ii, 1873, pp. 583 59.
The Ore Knoh Copper Mine and some related Deposife: Trans. Am. Tnst. Min.

Engineers, vol. ii, is?.'!, pp. 123-129.
Progress of Geology: Harper's Annual of Science and Industry, L873, p. xlviii.

(Includes a sketch of Hunt's Theory of rock Disintegration.)
Account of the crystalline Rocks of the Blue Ridge and their decomposed Condi-
tion: Proc. Bost. Soc. Nat. Hist., vol. xvi, October 15, is?:;, pp. L15-117.
On concentric Lamination of Rocks: Proc. Bost. Soc. Nat. Hist., vol. xv, January

L5, L873, pp. 261-262.
On the Geology of the White Mountains: Proc. Host. Soc. Nat. Hist., vol. xv, .March

5, 1873, pp. 309, 310.
On some Points in dynamical Geology: .1//;. Jour. Sci., vol. v, L873, pp. 264-270.
On the copper Deposits of the Blue Ridge: Engineering and Mining Journal, ls7.'i;

also Am. Jour. Sci., vol. vi, 1873, pp. 305-308.
Decomposition of crystalline Rocks (abstract): Am. Jour. Sci., vol. vii, 1873, pp.

GO, 61.
The Coals of the Hocking Valley, Ohio: Trim*. Am. Inst. Min. Engineers, vol. ii,

1874, pp. 273-278.
Notes on the Geology and economic Mineralogy of the southeastern Appalachians,

3 pages, reprint.
The coal and iron Region of southern Ohio considered with Relation to the Hock-
ing Valley Coal-field and its iron Ores, Salem, 1874, 78 pages and 2 maps,

reprint.
Geology of southern New Brunswick (abstract), 1874, 2 pages.
The Disintegration of Rocks and its geological Significance (abstract) : Proc. Am.

Assoc. Adv. Sci., part II, L874, pp. 39-41.
The Coal and Iron of southern Ohio, Salem, 1874, 78 pages.
Report on the Hoosac Tunnel : Massachusetts House Document No. 9, 1875.
On the decayed Rocks of Hoosac Mountain (abstract of the foregoing report):

Trans. Am. Inst. Min. Engineers, vol. iii, 1874, pp. 187-188.
Remarks on the Stratification of rock Masses : Proc. Host. Soc. Nat. Hist., vol. xvi,

January 7, 1874, pp. 237-238.
Breaks in the American Paleozoic: Canadian Naturalist, second ser., vol. vii, 1875,

pp. L60, Kd.
Metamorphism of Rocks : Canadian Naturalist, second ser. , vol. vii, L875, p. L62.
The Development of our mineral Resources: Harper's Magazine, ls7">, pp.

82 in.
The Geological Survey of .Missouri (a review): American Naturalist, April, 1875.
Remarks on the crystalline Rocks of Braintree, Massachusetts: Proc. BostonSoc.

Nat. Hist., vol. xvii, April 21, 1*7.">, pp. 508 .MO.
Professor Dana on the Alteration of Rocks : Proc. Boston Soc. Sot. Hist., vol. xviii,

November 17, L875, pp. His 1 1:; and 200.
(in the decayed Gneiss of Hoosac Mountain: Proc. BostonSoc. Sot. Hist., vol. xviii,

June -2. L875, pp. L06 His.
On the Boston artesian Well and ils Waters: Proc. Boston Soc. Sot. Hist., vol. xvii,

April 21, is?:., pp. 186 188.

BIBLIOGRAPHY OF T. STEK.RY HINT. ' 391

The Cornwall Iron Mine and some related Deposits in Pennsylvania: Trans. Am.
Inst. Min. Engineers, vol. iv, 1876, pp. 319-325.

A new Ore of Copper and it* Metallurgy: Trans. Am. Inst. Min. Engineers, vol. iv,
1876, pp. 325-328.

On the History of the crystalline stratified Bocks (abstract) : Proe. Am. Assoc. Adv.
Sci., L876, pp. 205-208.

Geology of eastern Pennsylvania: I'm,-. .1;/*. Assoc. Adv. ScL, 1876, pp. 208-212.

A Century's Progress in theoretical Chemistry: American Chemist, vol. v. pp. 4(i-
51 ; Popular Scienct Monthly, vol. vii, p. 420.

Progi'ess of Geology : Harper's Annual of Science, 1876, pp. lxxxix-civ.

The Quebec Group in Geology: Proc. Boston Soc. Nat. Hist., vol. xix, October 18,
1876, pp- 2-4.

TheGoderich [Canada] salt Region: Trans. Am. Inst. Min. Engineers, vol. v, IS77,
pp. 538-560; see also abstract in Am. .I<mr. Sci., vol. xiii, 1*77, pp. 231, 232.

Progress of Geology : Harper's Annual of Science, 1877, pp. L64-182.

Special Report on the trap Dike's and Azoic Rocks of southeastern Pennsylvania :
Second Geol. Survey of Pennsylvania, report E, part 1, 1878.

The geological Relations of the Atmosphere (abstract): Nature, vol. xviii, p. 475.

Progress of Geology : Harper's Animal of Science . 1S7S pp. 287-312; see also Smith-
sonian Report, 1878.

Sur les relations geologiques de l'atmosphere : Comptes !>'■ ml",* </< VAcad. d< Sci.
de France, lxxxvii, 28 September, 1878, p. 453.

Geology of the Eozoic Rocks of North America: Proc. Host,,,, Soc. Nat. Hist., vol.
xix, January 2, 1878, pp. 275-279.

The Origin and the Succession of the crystalline Rocks of North America: Geolog-
ical Magazine, 1878, p. 166; also Nature, vol. xviii, p. 44:;.

( Iheniical ami geological Essays, 1878.

The History of some pre-Cambrian Rocks in America ami Europe : Canadian Nat-
uralist, vol. ix, 1879, p. 257; see also Am. Jour. Sri. vol. xix, L880, pp. 268-283.

The Coal ami Iron of the Hocking Valley, Ohio: Trans. Am. Ins!. Mi,,. Engineers,
vol. vii, 1879, pp. 313-315.

Remarks on the Cambrian Rocks of the British Islands:: Proc. Boston Soc. \,,t.
Hist., vol. xx. February 5, 1879, pp. 14U, 141 ; see also Am. Jour. Sri, vol. xix.
L880, pp. 268-283.

The chemical ami geological Delations of the Atmosphere: Am. Jour. Sri., vol.
xix, isso, pp. 349-363; see also abstract in Nature, August 29, L878; Comptes
Rendues del 'Acad. <!■ Sci. de France, September 23, I878,and Proc. British Assoc.
Adv. Sri, 1878.

On the recenl Formation of Quartz and Silicification in California: Am. Jour. Sci.,
vol. xix, issu, pp. 371, 372.

The Genesis of certain iron Ores : Proc. Am. Assoc. Adv. Sci. L880 ; Canadian Nat-
uralist, vol. ix, December, L880, p. 134.

< ieological Notes or Abstracts of recent Papers :
1. The Taconic Sy tern in Geology.
•_'. The ( renesis of certain iron ( )i«
:;. The < >rigin of Anthracite.

4. The recent Formation of Quartz and on Silicification in California.
< 'anadian Naturalist, vol. ix, 1880, pp. 429-437; for the last paper, see also Am.
.Um,-. Sri.. May, isso, pp. 371, 372.
Coal and Iron in southern Ohio, etc, Boston, L881.

392 PROCEEDINGS OF OTTAWA MEETING.

The Hydro-metallurgy of Copper and its Separation from the precious Metals:

Trans. Am. Inst. Min. Engineers, vol. x, 1881, pp. 11-25.
Review ofthe Progress of Geology : Smithsonian Report, L882.
The Relations of the natural Sciences: Canadian Naturalist, vol. x, L882, pp. 257-

264; see also Trans. Roy. Soc. Canada, vol. i, sec. iii, L882, p. 1.
Celestial Chemistry from the Time of Newton: Proc. Cambridge [Eng.~\ Philos. Sue.,

Issi ; and reprinted in Am. .lour. Sri., vol. xxiii, 1882, pp. L23-133.
Progress of Geology : Smithsonian Report, 1883.
The Geology of Port Henry, New York (abstract): Canadian Naturalist, vol. x,

1883, pp. 420-422.
Coal and Iron in Alabama : Trans. Am. Inst. Min. Engineers, vol. xi, 1883, pp. 236-248.
The decay of Rocks geologically considered (read before the National Academy of

Sciences, Washington, April 17, 1883): Am. Jour. Sri., vol. xxvi, 1883, pp.

1K0-213.
The Geological History of Serpentines, including Studies of pre-Cambrian Rocks :

Trait*. Roy. Soc. Canada, vol. i, sec. iv, 1883.
The Taconic Question in Geology: Trans. Roy. Soc. Canada, vol. i, sec. iv, 1883.

The two last papers are reviewed in Am. Jour. Sci., vol. xxvii, 1884, pp.

481), 490.
On the Origin of the crystalline Rocks: American Naturalist, June, 1884; see also

Canadian Record of Sci., vol. i, 1884, pp. 75-77; -1//*. Jour. Sci., July, 1884, and

Nature, July 3, 1884, p. 227.
The apatite Deposits of Canada: Canadian Record of Sci., vol. i, 1884, pp. 65-75;

also 'Trans. Am. Inst. Min. Engineers, vol. xii, 1884, pp. 459-468.
The Cambrian Rocks of North America (abstract) : Canadian Record of Sci., vol. i,

L884, pp. 77-81.
The Eozoic Rocks of North America (abstract) : Canadian Record of Sci., vol. i,

L884, pp. 82-88.
The Origin of crystalline Rocks: Trans. Roy. Soc. Canada, vol. ii, sec. iii, 1884,

p. 1 ; see also abstract in Am. Jour. Sci., vol. xxvii, 1884, pp. 72-74.
An historical Account of the Taconic Question in Geology, with a Discussion of

the. Relations of the Taconic Series to the older crystalline and to the Cam-
brian Rock: Trans. Roy. Soc Canada, vol. ii, sec. iii, 1884, p. 125.
Observations sur les roches magnesiennes du groupe de la riviere Hudson, que M.

Logan a dec-rites dans la seance #du 7 mai 1885, p. 104: Bull, de la Soc. Geol. de

France, 2e ser., tome xii, 2e part, 1885, pp. 1029-1032.
The Classification of natural Silicates (abstract): Canadian Record of /Sci., vol. i,

1885, pp. 1-".) L35 and 244-247.
The < reognosy of crystalline Rocks (abstract) : ( 'anadian Jocord of Sci., vol. i, 1885,

pp. 147, I4s.
Biographical Notice of Benjamin Silliman: Trans. Am. Inst. Min. Engineers, vol.

xiii, 1885. pp. 782-785.
An electrical Furnace for Reducing refractory Ores: Trans. Am. Inst. Min. Engi-
neers, vol. xiv, L885, pp. V.V2 -495.
Note on the apatite Region of Canada: Trans. Am. Inst. Min. Engineers, vol. xiv.

L885, pp. 495, 496.
( )n a natural System in Mineralogy, \\ ith a Classification of native silicates : Trans.

Roy. Soc. Canada, vol. iii, sec. iii, 1885, |>. 25. Abstracts printed in American

Naturalist, .Inly, L885, and ('anadian Record of JSci. , vol. i, L885, pp. 129 and 244,

and also extract in Canadian Record of Sci. , vol. ii, 1886, pp. 1X6-1X9.

Bill. <.i-..i Sew \m.. Vol. 4, 1892.

J. F. KEMP — MEMORIAL OF J. S. NEWBERRY. 393

The Law of Volumes in Chemistry: Canadian Record of Sci. , vol. ii, 1886, pp. 261-

264.
The genetic History of crystalline Rocks [The Crenetic Hypothesis] : Trans. Roy.

Soc. Canada, vol. iv, sec. iii, 1886, p. 7.
Mineral Physiology and Physiography; a second Series of chemical and geological

Essays, Boston, 1886, Svo, 710 pages.
Supplement to "A natural System in Mineralogy," etc: Trans. Roy. Soc Canada,

vol. iv, sec. iii, 1886, p. 63.
( rastaldi on Italian Geology : Geological Magazine, vol. iv, 1887, pp. 531-540 ; and an

abstract printed in British Assoc. Adv. Sci., 1887, pp. 70.'!, 704.
Elements of primary Geology : Geological Magazine, vol. iv, 1887, pp. 493-500; at-
tracts in Eng. and Min. Jour., vol. xliv, 1887, p. 210; Nature, vol. xxxvi, 1887,

p. 574; and Proc. British Assoc. Adv. Sci., 1887, p. 704.
The Taconic Question restated: American Naturalist, vol. xxi, 1887, pp. 114, 238,

312; reviewed by Dana in Am. Jour. Sci, vol. xxxiii, 1887, p. 412.
An electrical Furnace for reducing refractory Ores: Canadian Record of Sci., vol. ii,

1887, pp. 52-55.

Further Notes on the Hydro-metallurgy of Copper: Trans. Am. Inst. Min. Engineers,
vol. xvi, 1SS7, pp. 80-82.

Chemical Integration : Am. Jour. Sci., vol. xxxiv, 1887, pp. 116-127.

On crystalline Schists : Nature, vol. xxxviii, 1888, pp. 519-522.

Les schistes Crystallines : International. Geological Congress, London, 1888.

[Remarks] on the Archean ; on Serpentine; Classification of Eruptives ; Nomen-
clature of Lower Paleozoic Formations : Reports of American Sub-committees to
tin International Congress of Geologists, 1888.

Mineralogical Evolution: Trans. British Assoc Adv. Sci., 1888, p. 704; also in Gco-
logical Magazine, Noveinher, 1887, and Canadian Record of Sci., vol. iii, 1888,
pp. 242-245, and an abstract in Chemical News, June 29, 1888.

The Study of Mineralogy: Canadian Record of Sci., vol. iii, 1888, pp. 2:]f>-242.

The Classification and Nomenclature of metalline Minerals (abstract) : Trans. Roy.
Soc. Canada, vol. vi, sec. iii, 1888, p. 01 ; ahstracts also in J'ror. Am. Philos. Soc,

1888, and in Chemical News, August 10 and 17, 1888.

The iron Ores of the United States: Trans. Am. Inst. Min. Engineers, vol. xix, 1890,

pp. 1-17.
Tahle of the Geological Formations: Macfarlane's Am. Geological Railway Guide,

1890.
Systematic Mineralogy based on a natural Classification, New York, 1891, 391

pages.

A memorial of J. S. Newberry, in the absence of the author, was read
by H. L. Fairchild.

MEMORIAL OF JOHN STROXO NEWBERRY
BY J. F. KEMP

The circle of American scientific men who, at least in the earlier
periods of their work, may be most correctly described as naturalists,
grows smaller year by year. The ever-widening range of facts and re-

o'.ll PROCEEDINGS OF OTTAWA MEETING.

corded observations with which an investigator of to-day must be
familiar tends to concentrate attention upon more and more restricted
lines. When, thus, one is removed who has left the stamp of his genius
upon many departments of science, in all of which he was conspicuous,
ami when we sum up his many activities in such brief form as to grasp
nt once an appreciation of them, our admiration for his abilities is the
more enhanced and our feeling of loss is the greater. Such a man was
the late Professor John Strong Newberry.

Dr Newberry first saw the light in the little town of Windsor, Con-
necticut, December 22, ls-_>2, and therefore at the time of his death,
December 7, 1892, lacked about a fortnight of being seventy years of age.
His ancestors were among the founders of Windsor, which they helped
to settle in 1635. Dr Newberry's grandfather, Honorable Roger Newberry,
was a director in the "Connecticut Company" that purchased the tract
in northeastern Ohio known as the Western Reserve, and thither his
father, Henry, removed in 1824. when the late professor was two years
of age. The family settled at Cuyahoga Falls, south of Cleveland, and
there Dr Newberry's boyhood was passed. The elder Newberry became
actively engaged in opening up the coal resources of eastern Ohio and in
obtaining an outlet for them to Lake Erie. His sou was thus reared in
the midst of mining and of that kind of mining which especially devel-
oped fossil plants. In his later years Dr Newberry took pleasure in re-
counting the delight which he felt while yet a hoy in uncovering these
delicately preserved fronds from their enclosing shale.

After preparation for college, the future professor entered the Western
Reserve University at Hudson, Ohio, and was graduated in 1846. He
next studied medicine in the Cleveland Medical School, and received his
degree of M. D. in 1848. The attractions of European study led him
shortly afterward to Paris, where he spent two years in further prepara-
tion in medicine. Interest in fossils prompted him also to seek in-
struction in paleontology, hut as he was accustomed many years later to
speak of the unsatisfactory character of his opportunities, they probably
amounted to little. On returning to America he began, in 1851, the
practice of medicine in Cleveland, and soon gained a wide clientele. It
is a, curious tact that in the same year in which Dr Newberry sought
European advantages, Leo Lesquereux, his great contemporary, migrated
to America.

While Dr Newberry's medical practice increased and many influences
conspired to develop him into a. settled and successful physician, his
tastes for natural history kept making his profession more and more
irksome. Friends at Washington were not slow in taking advantage of
this and finally induced him to abandon Cleveland and active practice.

J. F. KEMP MEMORIAL OP J. S. XKWnKRRY. 395

He became in May, 1855, assistant surgeon and geologist to the explor-
ing party that was sent out by the War Department under Lieutenant
K. S. Williamson to traverse the country between San Francisco and the
Columbia river. Two years later his papers on the botany, zoology and
geology of the region appeared in volume vi of the " Reports of Explora-
tions and Surveys to ascertain the most practicable and economical
Route for a Railroad from the Mississippi river to the Pacific ocean,
made in 1853-'56, Washington, 1857."

Dr Newberry next became geologist to the Ives expedition, as it is
generally known, from its commander, Lieutenant Joseph C. Ives. Tins
party was sent to explore the Colorado river in 1857-'58.

After sailing up the river from the gulf of California in a little steamer
to the mouth of the Grand canyon the party spent nearly a year in the
study and exploration of the lower Colorado and the plateau lying east-
ward. Dr Newberry not only gained an acquaintance with the superb
geologic sections and phenomena of erosion there afforded, but also
with the Pueblo tribes of Indians, in whom he ever afterward took the
deepest interest.

The geologic portion of the final report forms what is now its most
valuable and interesting part. The full title is, " Report upon the Colo-
rado River of the West, explored in 1857-'58," Washington, 1861.

In 1859 Dr Newberry was again in the field as naturalist of an expe-
dition under Captain J. N. Macomb, which explored the San Juan
country, in southwestern Colorado, and the adjacent parts of Utah, Ari-
zona and New Mexico. Many observations on the coal seams and gen-
eral geology of this country are recorded, to whose accuracy and impor-
tance later and fuller reports have given ample confirmation. The results
of this expedition were not made public until 1876, owing in part at
least to the demoralization of the war. Tbey then appeared under the
title, " Report of the Exploring Expedition from Santa Fe to the junction
of the Grand and the Green Rivers," Washington, 1870.

Shortly after the trip was completed the civil war broke out. Dr New-
berry was summoned to the newly organized Sanitary Commission, in
which, on June 14, 1861, he took bis place, although at the time attached
to the War Department. Rut the work of the commission was impera-
tive, and in September Dr Newberry resigned from the War Department
and became secretary of the western branch of the commission, with
headquarters at Louisville. All the operations in the Mississippi valley
and its tributaries were under bis direction. Distributing depots were
quickly established at many points. At times Dr Newberry followed
the army and was himself present at the battle of Chattanooga, over-
seeing the work of his organization. At the close of the war lie made

LIX— Bum,. GF.or,. Soc. Am., Vol. I 1892.

396 PROCEEDINGS OF OTTAWA MEETING.

his final report. It is a volume of 543 pages and exhibits the greal
labors performed and the enormous sums which were expended under
his administration. Dr Newberry had by this time returned to Wash-
ington and had become attached to the Smithsonian Institution. He
also held a professorship in the Columbian University of Washington
during 1856-1857.

In 1864 the School of Mines, < Jolumbia College, New York, was founded,
and in 1866 the chair of geology and paleontology was created, anil a
call was extended to Dr Newberry. He accepted and remained in the
uninterrupted discharge of his duties until a stroke of paralysis, Decem-
ber •".. 1890, made work impossible. It was never resumed.

This long interval of twenty years is marked by incessant activity, for,
in addition to instruction in the college, a vast amount of investigation
and writing was carried on. Opportunities for scientific work and dis-
tinction outside of New York appeared and made possible the greatest
efforts of his life. When the legislature of ( >hio established a state geo-
logical survey in 1869, Dr Newberry, who had all along kept his house-
hold and home in Cleveland, was called by Governor Hayes to the
directorship. Active organization was soon effected and a comprehen-
sive scheme of work was blocked out. Three reports of progress were
issued, the last extremely brief. The final reports comprised four vol-
umes on the geology of the state, two on its paleontology, one geologic
atlas and a report on the zoology. They all appeared between 1869 and
1882. One or two were printed in German as well as in English. A
large part of the field-work was done by the director himself, and the
descriptions of a number of counties are from his pen. Of course the
summation is also his. In paleontology notable discoveries were made
of fossil fish and fossil plants. The reports on these two groups by Dr
Newberry probably attracted as much attention from scientific men as
any other portions of the survey's work. Observations on the geologic
history of the great lakes and their relationships to the glacial period
were recorded, which have proved fruitful of later results. Not a few
men began their geologic work in the survey or took part in it. who have
since become leaders. ('<. K. Gilbert, h\ D. Irving, Henry Newton. N.
II. Winched and Edward Orton, the able and courteous director of the
present Ohio survey, may he mentioned. Probably an error of judg-
ment was committed in postponing the economic work until the last, for
before these reports, which always have greatest value and interesl to the
people ;it large, were reached, the legislature cut short the appropriation
on the ground, as one rural member said, that too much money was de-
voted to clams and salamanders.

Dr Newberry also did :i large amount of paleontologic work for the

.1. F. KEMP— MEMORIAL OF J. S. NEWBERRY. 397

Illinois survey, especially on vertebrate fossils. A still more extended
undertaking was the description of the later, extinct floras in the west,
materials for which had been gathered by the Hayden survey. A volume
of ) dates was issued in 1878, but, although begun nearly fifteen years ago,
the manuscript is not entirely complete, and, if published, will form a
posthumous work under the editorship of the professor's old student
and friend, Arthur Hollick.

In association with the New Jersey survey, Dr Newberry also under-
took the description of the flora of the Amboy clays. This manuscript,
with some editorial completion by Mr Hollick, will also appear as a
posthumous work. The description of the fossil fishes and plants of the
eastern Triassic strata was pushed to a conclusion and appeared in 1888,
as Monograph XIV of the United States Geological Survey. A more
elaborate work on the Paleozoic Fishes of North America came out in
the following year as Monograph XVI of the same survey. Both works
are extensively illustrated by plates. For the preparation of these he
was appointed paleontologist on the survey in 1884.

In addition to his paleontologic papers, Dr Newberry wrote also many
shorter contributions for the scientific journals on subjects connected
with economic geology. In this connection it may be stated that he was
one of the judges at the Centennial and was the author of the report on
building stone. Several papers in Appleton's Cyclopedia are from his
pen, and of Johnson's Encyclopedia he was one of the editorial staff.
This sketch would be incomplete without mention of the high regard
that was felt for his opinion on the value of mines, both for metals and
coal. Ilis advice was often sought, and frequent trips to the west and to
Mexico widened his range of observation.

When the National Academy was founded, Dr Newberry was named
by Congress as one of the incorporators and became a familiar figure at
its meetings. In 1867 his alma mater honored herself and him by be-
stowing the degree of LL.D. In the same year he was president of the
American Association for the Advancement of Science and delivered the
annual address at Burlington, Vermont. Likewise in 1868, soon after
his coming to New York, he was chosen president of the New York
Academy of Sciences, Professor C. A. Joy, the previous incumbent, grace-
fully and generously retiring to give the Doctor an appropriate introduc-
tion to the scientific circles of tic metropolis. For twenty-four years Dr
Newberry remained president of this body, and during the last years of
his life and at the time of his death was its honorary president. Dr
Newberry was also president of the Torrey Botanical Club and occupied
the position during the fen years between 1880 and 1890.

Largely in immediate recognition of his paleontologic works, the Ceo-

398 PROCKE DINGS OF OTTAWA MEETING.

logical Society of London conferred on l>r Newberry in 1888 the Mur-
chison gold medal, which is awarded by the society for distinguished
services in geology. In presenting the medal President Judd, and in
receiving it in behalf of Dr Newberry, Sir Archibald Geikie referred in a
most appreciative way to his work. When the long-pending Geological
Society of America finally took form at Cleveland in 1888, Dr Newberry
was present and shared in the preliminaries of organization. At the see-
mid election of officers, in New York, December 26, 1889, lie was chosen
first vice-president. The crowning- honor of his life came, however, in
L891.

In the late seventies the-subject of an International Congress of Geolo-
gists was broached in the American Association and Dr Newberry was
appointed one of the committee to carry the matter through. The move-
ment led to the organization of the congress, which has now had four
meetings at intervals of three years and in several countries. The last
one was in Washington in August, 1891, and chose for its presiding offi-
cer the one in whose memory these lines are penned. The honor was a
fitting tribute to a long and fruitful life, but it came after its recipient
was too weakened to take the chair. From his far-distant summering
place on Lake Superior he was forced to send his messages of greeting
to the congress.

It was in the winter of 1889-'90 that exhausting labors began to tell
heavily on a constitution that had seemed so proof against fatigue that
it knew not how to yield. A heavy cold and attendant weakness gave
warning that certain limits must he regarded, but the professor, alter a
brief absence, again appeared before his classes. When the long summer
vacation of 1890 came, he wrought day alter day with an amanuensis on
his report upon the Amboy flora. The strain was too severe and cul-
minated the' following Decemberwith a paralytic stroke, from the effects
of which the honored teacher and investigator never recovered.

Dr Newberry's skillful touch has been felt in almost all lines of geologic
work and in almost all departments of natural history. He was a most
indefatigable collector, and the museum which he leaves at Columbia
is a monument to his memory. Its wealth in fossil fish makes it unique
mid famous among geologic museums.

Dr Newberry had also a strong passion for music, and in his earlier
career was wont to solace the long hours of western expeditions with his
violin. He was likewise gifted with skill in sketching, such that many
illustrations of fossils and of scenery in his reports an' from his own
hand. He wrote in charming and attractive literary style, and in de-
scriptions of the grand phenomena of the west often manifested a highly
artistic use of language.

BIBLIOGRAPHY OF J. S. NEWBERRY. -.'••'.I

In his scientific work he sometimes displayed almost the insight of a
seer, and from his ability to grasp, as it were by intuition, the bearings
of many widely isolated facts, he has shown a quite prophetic instinct.
His determinations of strata in the west, although based on the hasty
itineraries of exploring parties, have been very generally corroborated
by later and more deliberate work. The same is true of his early views
on the origin of petroleum, and on the buried channels that have been
since discovered around nearly all the waterfalls of the central part of
the country. He was withal extremely conservative on many doubtful
points and before his classes was always very cautious of statement.
With his students his relations were marked by great kindliness, and by
them he was universally beloved.

Dr Newberry was married in Cleveland, in ISIS, to Miss Sarah B.
Gaylord, who, with six of their seven children, survives him.

The following bibliography contains those titles of Dr Newberry's
writings which are to be regarded as broadly included under geologic
science. A chronologic list of all his writings is published in the Trans-
actions of the New York Academy of Sciences, volume xii, pages 174-185,
and in the "American Geologist" for July, 18-93. A list of his botanic
papers, with a list of the plants named after him, is printed in the Bulle-
tin of the Torrey Botanical Club for March, 1893.

BIBLIOGRAPHY.
ARCHAEOLOGY.

The Earliest Traces of Man Found in North America: Proc. N. V. Lye. Nat. Hist.,

vol. i, 1870, p. -2.
Ancient Civilizations of America: Abstract, Trans. A'. Y. Acad. Sci., vol. i, 1882, p.

L20.
The Ancient Civilizations of America : Trans. N. Y. Acad. Sci. , vol. iv, L885, p. 47.
Ancient Mining in North America: American Antiquarian, vol. xi, 1889, |>. L64.

The Man of Spy : Notice of the recent discovery of .two nearly complete skeletons
of paleolithic men in the gravel of Spy, near Liege, Belgium : Science, March
29, 1889.

ECONOMIC GEOLOGY.

Report on the Economic Geology of the Route of the Ashtabula and New Lisbon
Railroad: Cleveland, Ohio, 1857, 8vo, pp. 4!).

The oil Region of the Upper Cumberland in Kentucky and Tennessee: Cincin-
nati, L866, pp. 10.

Prospectus of the Neff Petroleum Company, Knox County, Ohio: L866, pp. 16-23,
pp. 40-43, < lambier, < >hio.

On Titaniferous Iron Ores: Proc. A\ Y. Lye. Nat. Hist., vol. i, L870, p. 223.

Geology in its Applications to Agriculture: Proc. Ohio Agric. Convention, L870, p.
65.

lull PROCEEDINGS OF OTTAWA MEETING.

The Marble Beds of Middlebury, Vermont: Proc. N. Y. Lye. Nat. Hist., vol. i. 1870,

p. 62.

Report on Vermont Marble: New York, 1872, Pamphlet, 8vo, pp. 12.

Report "ii the Central Vermont Marble Quarries: New York. 1873, Pamphlet, 8vo,

pp. 7.
The Gas Wells of Ohio and Pennsylvania: Proc. N. Y. Lye. Nat. Hist., vol. i, 1871,

P- -
Notes on Ajnerican Asphalts: American Cltemist, vol. ii. 1872, p. 427.

Coalsand Lignites of the Western States and Territories: Proc. N. )'. Lye. Nat.
Hist., second series, 1873, p. 41.

Water Supply of the City of Yonkers : American Chemist, vol. iii, January. 1873
p. 242.

The Iron Resources of the United States: Tnternatwnal Review, 1874, p. 75-1.

.Mineral Deposits: Appleton's Encyclopaedia, vol. xi, 1875, p. 577.

li^-j >- .rt Upon Building and Ornamental Stones : Reports and Awards, Group I. Cen-
tennial Exhibition, pp. 107-171, Philadelphia, J. B. Lippincott & Co., lv7r

Discovery of Mineral Wax (Ozocerite) in Utah: Am. J Sci., vol. xvii, 1879
p. 340.

Origin and Classification of Ore Deposits: School of Mines Quarterly, vol. i. March,
18S

Report upon the Properties of the Stormont Silver Mining Co.. Utah: Engineering
and Mining Journal, October 23, 18S0, p. 2

The Silver Reef Mines, Utah: Engineering and Mining Journal, January 1. 1881,

Note "ii the Copper Deposits of the Trias in New Mexico and Utah: Trans. N. )

Acad. Sci., vol. i. 1881, p. 20.
Coal and Iron of Southern Utah : Pamphlet, 8vo, New York, 1882, pp. 12.
The Gas Wells of Ohio: American Chemist, vol. i. p. 201.
Sierra Riea and San Carlos Mines, Chihuahua. Mexico: New York. 188
The Deposition of Ores: School of Mines Quarterly, vol. v, 1884.
Recent Discoveries of Rock Salt in Western New York: Trans. N. Y. Acad. Sci.,

vol. iv, 1885, p. 55.
Grahamite in Colorado: School of Mines Quarterly, vol. viii. 1887, p. 332.
Kersantite. a New Building Stone: School of Mines Quarterly,' vol. viii. 1887, p. 331.
The Great Falls Coal Field, Montana: Scliool of Mines Quarterly, vol. viii. 1>>s.7. p.

327.
The Probable Future of Gold and Silver: U. - ' Reports, No. -7. 18S7. p.

420.
The Coals of Colorado : School of Mines Quarterly, vol. ix. 1888, p. 327.
The Pavements of the Great Cities of Europe, with a Review of the Best Methods

and Materials for the City of New York: Trans. X. Y. A - .. vol. viii.

588, p. 41.
The Future of Gold and silver: School of M iy, vol. ix, 1888, p. 98.

Marble Depositsof the Western United States: School of Mi Q arterly, vol. x.

IS88, |.
The New < >il Field of Colorado and its Bearing on the Question of the Genesis of

1' troleum: Trans. N. )'. Acad. Sci., vol. viii. l^s p. 25.
The Oil Fields of Colorado - >l of Mines Quarterly, vol. x. January. 1888, p. 97.
The Pavements of New York: - »■ Mines Quarterly, vol. x 186

BIBLIOGRAPHY OF J. S. NEWBERRY. 401

Coal vs. Natural Gas: Black Diamond, August 3, 1889.

The Hock Salt Deposits of the Salina Group in Western New York : Trans. X. Y.
Am, I Sri., vol. ix, no. 2, 1889.

GENERAL GEOLOGY.

On the Origin of the Quartz Pebbles of the Carboniferous Conglomerate: Family

Victor, 1851.
On the Mode of Formation of Cannel Coal : .1;/;. Jour. ScL. vol. xxiii. 1857, p. 212,
Geology of California and Oregon: United States Pacific Railroad Report, vol. vi,

1S57, pp. 1-73, pi. v.
The Rock Oils of Ohio: Ohio Agr. Rep., 1859, and reprint, p. 10.
Explorations in New Mexico: Am. Jour. Sci., vol. xxviii, 1859, p. 298.
The State-House Well of Columbus, Ohio: Rep. of the Supt. of State- House, 18(30, and

reprint.
Geology of the Region traversed by the Colorado Exploring Expedition: Wash-
ington, 1861, 4to, pp. 153, pi. 6, 2 maps.
On the Age of the Coal Formation of China : .1*//. Jour. Sri., ii, xlii, 1866, pp. 151-

154.
The Surface Geology of the Basin of the Great Lakes : Proc. Boston Soc. Nat. Tlist.,

vol. ix, 1862, and reprint, pp. 7.
Sketch of the Geology of Ohio: Walling's Atlas of Ohio, 1868, with geological map.
Geological Survey of Ohio : Report of Progress for 1869, parti, pp. 1-52, map and

chart.
On the Surface Geology of the Basin of the Great Lakes and the Valley of the

Mississippi: Ann. Lye. Nat. Hist., vol. ix, 1870, p. 21.'!; see also .1///. Jour. Sri.,

ii, xlix, pp. Ill and 207, 1S70.
The Geological Survey of Ohio: Address delivered to the legislature, February 7,

1870, pp. 60.
The Ancient Lakes of Western America, Their Deposits and Drainage: Hayden's

U. S. Geol. Survey (Wyoming), 1870, p. 329.
Ancient Lakes of Western America: Proc. X. Y. Lye. Xnt. Hist., vol. i, 1870, p. 25.
Geological Survey of Ohio : Report uf Progress for 1870, pari i; Structure of the

Lower Coal Measures in Northeastern Ohio, pp. 1-53, 4 charts.
On the Red Color of Sedimentary Rocks Barren of Fossils : Proc. N. )'. Lye. Nat.

Hist., vol. i, 1870, p. 36.

Geological Survey of Ohio: Report of Progress for 1871, Columbus, Ohio, pp. 1-9.
Geology of Ohio : Gray and Walling 's Atlas of Ohio, 1872, with geological map.
Geological Survey of Ohio : vol. i, parti: Historical Sketch, Physical Geology,

( leological Relations and Geological Structure of Ohio, pp. hic>7, 1873.
< ieological Survey of Ohio: vol. i, part i, 1873, Geology of Cuyahoga County, pp.

111-200, 1 map.
Oeological Survey of Ohio: vol. 1, part i, 1873, Geology of Summit County, pp.

201-222, 1 map, 1 plate.
Geological Survey of Ohio : vol. ii, part i, Paleontology, 1S7.">, Preface, pp. I 8.
Cycles of Deposition in American Sedimentary Rocks: Proc. Am. Assoc. Adv. Sri.,

vol. xxii, 1873, p. 185.
Salina Group of the Upper Silurian: Proc. X. )'. Lye. Nat. Hist., 2d scries, 1873,

P. 11.

102 PROCEEDINGS OF OTTAWA MEETING.

Geological Survey of Ohio : vol. ii, part i. 1874, Preface, Surface Geology, the Car-
boniferous System, pp. 1 9, 1 180, plate 1. maps, I. The chapter on the Sur-
face Geology was reprinted with four maps.

(in t he structure and Origin of the Greal Lakes: Proc. X. )'. l/yc. Nat. Hist., *_M
series, I 874, p. L36.

Geological Survey of Ohio : vol. ii. part i, 1874, Geology of Erie County and the
Islands, pp. 183-205, 1 map.

Geological Survey of Ohio: vol. ii. part i, 1S74. Geology of Lorain County, pp.
206-224.

Parallelism of Coal Seams: Am. Jour. Sci., iii, vol. vii. 1X74, p. 367.

On the Lignites and Plant Beds of Western America: Am. Jour. Sci., iii, vol. vii.
1874, p. 399.

Geological Report, accompanying Report of the Exploring Expedition from Santa
1<Y', New Mexico, to the Junction of the Grand and the Green Rivers, in 1859,
under Captain J. M. Macomb: Washington, 1876, 4to, pp. L52, pi. lit.

Causes of the Cold of the Ice Period : Pop. Sri. Monthly, ix, p. 280, July, 1S70.

Geological Survey of Ohio : vol. iii. Geology, Preface. Review of Ohio Geology
and Local Geology of Tuscarawas. Columbiana, Portage, Stark, Jefferson and
Mahoning counties. 1S7S.

Geological History of New York Island and Harbor: Pop. Sri. Monthly, October,
ls;s. and reprint, pp. 20.

The Geological Survey of the Fortieth Parallel: Review, P.n>. Sci. Monthly, July,
1879.

I renesis of the Ores of Iron: School of Mines Quarterly, vol. ii. November, 1880.

The Genesis and Distribution of Gold : School of Mines Quarterly, vol. iii, Novem-
ber, 1881, p. 5.

The Origin and Drainage of the Great Lakes: Proc. Amer. Phil. Soc, December,

I SSI .

Geological Observations in Montana. Idaho, Utah and Colorado: Trans. X. Y.

Acad. Sci., vol. i, 1881, p. 4.
Volcanic Rocks of Oregon and Idaho: Trans. X. Y. Acad. Sci., vol. i, 1881, p. •">:;.
Geology of the Mammoth Cave: Trans. X. )'. Acad. Sci., vol. i. 1881-'82, p. 65.
II\ pothetical High Tides as Agents of Geological Change: Trans. X. )'. Acad. Sri..

vol. i. no. 4, 1882, p. so.
Hypothetical High Tides: Nature, vol. xxv, no. 16, February, 1882, p. 357.
Hypothetical High Tides: Nature, vol. xxvi. 1882, p. 56.
Origin and Relations of the Carbon Minerals: Abstract, Trans. X. )'. Acad. Sci.,

1882, pp. 100-111 : Annals X. V. Acad. Sci.] vol. ii, p. 267.
The Origin of the Carbonaceous Mattel- in Bituminous Shales : Annals N. )'. Acad.

Sri., vol. ii. 1882, p. 357.
<tn the Origin of Crystalline Iron Ore-: Trans. X. V. Acad. Sri., vol. ii. 1882.

p. L3.
The Evidences of Glaciation in North America: Trans. X. )'. Aral. Sri., vol. ii.

1882 '83, i'. L55.
Botany and Geology of the Country Bordering the Rio Grande: Trans. X. )'.

Acad. Sri., vol. vii, 1883, p. '.to.
Richthofen's China : Am. Jour. Sri., iii, vol. xxvi, 1883, p. L52.
The Physical C litions under which Coal was Formed: School of Mines Quarterly,

vol. iv. no. ::. April. L883, p. L69.

BIBLIOGRAPHY OF J. s. tfEWBERRY. 403

Notes on the Geology and Botany of the Country Bordering the Northern Pacific
Railroad: Annuls X. Y. Acad. Sri., vol. iii, 1884.

The Drift Deposits of Indiana: Annual Report of the Statt Geologist of Indiana, 1884>
p. 85.

Discussion of Dr N. L. Britton's Observations on the Geology of the Vicinity of
Golden, Colo. : Idem, p. 77.

The Eroding Power of Ice: School of .Vims Quarterly, vol. vi, January. 1885.

The Meeting of the Geological Congress at Berlin, 1885: Trans. N. Y. Arm!. Sri.,
vol. v, 1885, p. 20.

On the American Trias: Trans. N. Y. Acad. Sri., vol. v, 1885, p. 18.

On the Geological Ago of the North Atlantic: Trans. X. Y. Acad. Sri., vol. v. 1885,
p. 78.

On Cone in Cine: Geological Magazine, decade iii, vol. ii, 1885, p. 559.

New York State Geology and Natural History: Encycloped la Br'dannica, 9th edi-
tion, vol. xvii.

North America in the Ice Period: Pop. Sci. Monthly, November, 1886.

Earthquakes: School of Mines Quarterly, vol. viii, 1886.

Earthquakes, what is Known and Believed of Them by Geologists: Trims. X. Y.
Acad. Sci., vol. vi, 1886, p. 18.

Origin of Graphite: School of Mines Quarterly, vol. viii, July, 1887.

A New Meteorite from Tennessee: Trans. N. Y. Acad. Sci, vol. vi, 1887, p. 160.

Synopsis of Historical Geology: Ap/ilrion's Physical Geography, 1887.

The Origin of the Loess: School of Mines Quarterly, vol. x, 1888, p. 66.

The Classification of American Palaeozoic Rocks: Report of Am. Com. to the Inter-
national Geological Congress, 1888.

The Laramie Group ; its Geological Relations, its Economic Importance and its
Fauna and Flora: Trans. X. Y. Acad. Sci., vol. ix, no. 1, 8vo, pp. 6, 1889.

The Origin of Coal : N. Y. Tribune, February 13, 1890.

The Laramie Group: Bull. Geol. Soc. of America, vol. i, pp. 524-532, 1890.

PALEOZOOLOGY.

Description of the Quarries Yielding Fossil Fishes, Monti' Bolca, Italy: Family

Visitor, 1851.
On the Fossil Fishes of the Cliff Limestone: Annals of Scienc , 1853, p. 12.
New Genera and Species of Fossil Fishes from the Carboniferous Strata of Ohio :

Proc. Phil. Acad. Sci., 1856, p. 96.
Fossil Fishes of the Devonian Rocks of Ohio: Bulletin National Institute, January,

1857.
Notes on American Fossil Fishes: Am. four. Sci., vol. xx.xiv, 1862, pp. 73.
Report on the Fossil Fishes Collected on the Illinois Geological Survey by J. S.

Newberry and A. II. Worthen : Rept. Geol. Survey III., vol. ii, 1866, pp. 1-134,

pi. xiii. -

Fossil Fishes of Illinois, Newberry and Worthen: Geol. Surv. I/!., vol. iv, IS70,

Notes on Some New Genera and Species of Fossil Fishes from the Devonian Rocks

of Ohio: Proc. X. Y. Lye. Nat. Hist., vol. i, 1870, p. 152.
Geological Position of the Elephant and Mastodon in North America: Proc. X. )'.

Lye Nat. Hist., vol. i, 1870, p. 77.

LX— Bun. Geol. Soc. Am., Vol. i, 1892.

404 PROCEEDINGS OP OTTAWA MEETING.

Geological Survey of Ohio : Palseontology, vol. i, part ii. 1873, Descriptions of Fossil

Fishes, pp. --'17 355, pis. i-xvii.
Notes on the Genus Conchiopsis, Cope: Proc. Acad. Nat. Sri. Phila., Is7.;. p. 125.
Geological Survey of Ohio: vol. ii. pari ii, Palseontology, preface, Descriptions of

Fossil Fishes, pp. 1 -64, 1875.
Description of Fossil Fish Teeth of Harrison County, Indiana: Rept. Geol. Surr.

Tnd., 1878, p. 341.
Descriptions of New Palaeozoic Fishes: Annals N. Y. Acad. Sri., vol. i, L879, p. 188.
Fossil Fishes from the Trias of New Jersey and Connecticut: Annate X. )'. Acad.

Sri., vol. i. 1879, p. 127.
Fossil Fishes from the Devonian Rocks of Ohio: Trans. N. Y. Acad. Sci., vol. ii.

L883, p. 14.).
Placoderm Fishes from the Devonian Rocks of Ohio : Trans. X. Y. Acad. Sri., vol.

v, 1885, p. 25.
Sur les Restes de Grands Poissons Fossils, Recemmant Decouverts dans les Roches

Devoniennes de L'Amerique du Nord : Comptes Rendus de la Trotefeme Session du

Congres GSologique International, Berlin, 1885, p. 11.
Description of a New Species of Titanichthys : Trans. X. Y. Acad. Sri., vol. vi, 1887,

p. 164.
Fauna and Flora of the Trias of New Jersey and the Connecticut Valley : Trans.

X. Y. Acad. Sri, vol. vi, 1887, p. 124. Sec also Monograph xiv, V . S. Geol.

Surv., cited under Paleobotany. 1888.
Cselosteus, a New Genus of Fishes from the Carboniferous Limestone of Illinois:

Trans. X. Y. Acad. Sri., vol. vi, 1887, p. 137.
Structure and Relations of Edestus: Annals X. Y. Acad. Sri., vol. iv, 1888, p. Id."'.

pi. iii.
A New Species of Rhizodw from the Mountain Limestone of Illinois : Trans. X". Y.

A <;,</. Sri., vol. vii, 1888, p. 165.
The Fossil Fishes of the Erie Shale of Ohio: Trans. X. Y. Acad. Set., vol. vii, 1888,

p. 1 78.
The Palaeozoic Fishes of North America : Monograph xvi, U. S. Geological Survey,

1889, 4to, pp. 228, plates 53.

PALEOBOTANY.

On the Structure and Affinities of Certain Fossil Plants of the Carboniferous Age :

Proc. Am. Asso., L853, p. 157 j Annals of Science, vol. i, p. 268.
On the Carboniferous Flora of Ohio: Proc. Am. Assoc, is.").",. ]>. 163; Annals <;/

Sr'u nee, vol. i, p. 280.
Catalogue of the Fossil Plants of Ohio : Annate of Science, 1853, vol. i,pp. 95and 106,
Fossil Plants from the Ohio Coal Basin: Annals of Science, vol. i, Cleveland, 1853

pp. 2 3, 95 97, 106-108, Kit L65, 268 270.
New Fossil Plants from Ohio: Annals of Science, 1853, pp.^16, 128 and 153.
Fossil Plants from the Cretaceous of Kansas and Nebraska (from a letter to Meek

and Hayden) ; Am. Jour. Sci., ii, xxvii, L859, pp. 31-35.
Cretaceous and Tertiary Plants: Hayden's Report mi Exploration of Missouri ami

Yellowstone Rivers, Washington, L859 '60, p. 146.
The Ancient Vegetation of North America: Am. Jour. Sci., vol. xxix, I860, p. 208.
The American Cretaceous Flora: Am. Jour. Sci., vol. xxx, I860, p. 273.

BIBLIOGRAPHY OF .1. S. NEWBERRY. 405

The Ancient Vegetation of North America: Canadian Naturalist and Geologist, vol.
vi, Montreal, 1861, pp. 73-80.

Description of Fossil Plants Collected by the N. W. Boundary Commission : Proc.
Bost. Soc. Nat. Hist, vol vii, 1863, and Reprint, pp. 19.

Report on the Fossil Plants Collected in China by Mr Raphael Pumpelly : Smith-
sonian Contributions, 1868, p. 119, pi. 1.

Notes on the Later Extinct Floras of North America: Annals Lye. Nat. Hist., vol.
ix, 1870, p. 1, Reprint, 8vo, pp. 7(5.

Notice of Fossil Plants from the Cretaceous Sandstones of Fort Darker, Kansas,
and from the Miocene of Bridge Creek, Oregon: Proc. N. Y. Lye. Nat. Hist.,
vol. i, 1870, p. 14s.

Notice of Angiospermous Leaf-impressions in a Red Sandstone Bowlder found in
Excavating the Foundations of a Gas Office in Williamsburg, L. I. ; Proc. N.
Y. Lye. Nat. Hist, vo>f i, 1871, pp. 149, 150.

Geological Survey of Ohio: vol. i, part ii, 1873; Description of Fossil Plants, pp.
355-385, eight plates.

Notice of Coniferous Remains in Lignite Beds near Keyport, N. J. : Proc. X. )'.
Lye. Nat Hist., second series, January 3 to March 30, 1873, pp. 9, 10.

Notice of Angiospermous Leaves in Red Shale at Lloyds' Neck, L. I. : Idem, Jan-
uary 5 to June 1, 1874, p. 127.

On the So-called Land Plants of the Lower Silurian of Ohio: Am. Jour. Sci., iii,
viii, 1874, pp. 110 and 160.

Fossil Botany : Johnson's Universal Cyclopaedia., vol. ii, 1S77, pp. 231-236.

Illustrations of Cretaceous and Tertiary Plants: Plates by Newberry, names by
Lesquereux, Washington, 1878.

Geological History of the North American Flora: Bulletin Torrey Botanical Club,
July, 1880, p. 74.

American Cretaceous Flora : Nature, xxiv, pp. 191, 192.

Description of Fossil Plants from Western North America: Proc. U. S. Xnl. Mu-
st urn, 1882, p. 502.

Notes on Fossil Plants from Northern China: Am. Jour. Sci., vol. xxvi, 1SS3, p.

12:;.

Notes on Fossil Plants from Northern China: Annalsftnd Mn</. Nat. Hist., fifth se-
ries, xii, pp. 172-177.

On a Series of Specimens of Siliciiied Wood from the Yellowstone Region, Exhib-
ited by Mrs. E. A. Smith: Trans. X. Y. Acad. Sri., iii, 1883-'84, p. :;:;.

Some Peculiar Screw-like Casts from the Sandstones of the Chemung Group of
New York and Pennsylvania: Idem, pp. 3.']-34.

Description of Spiraxin, a Peculiar Screw-like Fossil from the Chemung Rocks:
Annals X. )'. Acad. Sci., vol. iii, No. 7, June, 1885.

On the Fossil Plants of the New Jersey Cretaceous: Bull. Torrey Bot. Clul>, xii, p.
121.

Saporta's Problematical Organisms of the Ancient Seas: Review, Science, June 19,
1885.

On the Cretaceous Flora of North America: Proc. A. .1. A. S., 1886, p. 216.

Flora of the Amboy Clays : Hall. Torrey Bot. Club, vol. xiii, 1886, p. .">:'>.

A New Species of Bauhinia from the Amboy Clays: Bull. Torrey Hoi. Club, vol.
xiii, 1886, p. 77, pi. 1.

The Cretaceous Flora of North America: Trans. X. Y. Acad. Sri., vol. v, February,
1886.

l(li; PROCEEDINGS OF OTTAWA MEETING.

The Ancestors of the Tulip Tree : Bull. Torrey Bot. Club, vol. xiv, January, L887.

Fossil Fishes and Fossil Plants of the Triassic Rocks of New Jersey and the Con-
necticut Valley: Monograph xiv, U. S. Geol. Sin-., L888. See also under Paleo
zoology, Animal, Trans. X. V. Acad.. Sci., vol. vi, L887, p. 124.

Triassic Plants from Honduras: Trim*. X. )'. Acad. ScL, vol. vii, 1888, p. 113.

Rhtetic Plants from Honduras: Am. ./our. Sci., vol. xxxvi, 1888, p. 342.

Devonian Plants from Ohio: Jour. Cincinnati Soc. .Vo/. Hist., xii, pp. 4s-.")4.

Remarks on Fossil Plants from the Puget Sound Region, in C. A. White'.- " On
Invertebrate Fossils from the Pacific Coast " : Bull. U. S. G. S., no. 51, p. 51.

The Flora of the Great Falls Coal Field, Montana,: Am. Jour. Sci., iii, xli, 189J
pp. 191-201, pi. 14.

The Genus Sphenophyllum : Jour. Cincinnati Soc. Nat. ///*/., -xiii, pp. 212-217.

PHYSIOGKAPHY.

On the Currents of the Gulf Stream and of the Pacific oil' Central America : Family

Visitor, 1851.
Deep Sea Dredging* : Proc. N. Y. Lye, Nat. Hist., vol. i, 1870, p. PHI.
On the Results of the Removal of Forests: 1'euc. X. )'. Lye. Nat. Hid., second

series, is?.",, p. 31.
Winds and Ocearj Currents : Science, January, 1886.
( >n Sea-level and Ocean Currents: Science, July, 1886.
>ea-level and Ocean Currents : Science, October, 1886.

Dr Newberry was also one of the editors of Johnson's Encyclopaedia, having
charge of geology and paleontology. He wrote many articles on these subjects
for its pages in LS7o and the years immediately following.

Biographic sketches of Dr Newberry have been published in all the current
biographic dictionaries and cyclopedias. Portraits of him appear accompanying
such sketches in Men of Progress, 1870-71, page .'!17, and Contemporary Biography
of New York, volume v, 1887, page 255. The Popular Science Monthly, volume
ix, page491, 1876, contains a sketch, with portrait, and in Fairchild's History of
the New York Academy of Sciences there is an excellent artotype.*

A memorial of .1. H. Chapin, in the absence of the author, was read
by C. II. Hitchcock.

MEMORIAL OF JAMES HENRY CHAPIN

BY w. M. DAVIS

James Henry Chapin, an original member of our Society, was born in
Leavenworth, Indiana, on December 31, 1832. He died in South Nor-
walk, Connecticut, on March 14, 1892, in his sixtieth year. He was a

*Sinee his death memorials have appeared, with portraits, in the Engineering and Mining
Journal, December 17. 1892, page 581; tin- Scientific Vmerican, December 31, 1892, page 123; the

Si li""l of Mini s Quarterly, Ji I \ . 1893, page '>".. u ith two steel portraits, "in- taken in 1865 tun I

I 887 : Oil- Bulletin "I the Torrey Botanical Club, March, L893, w it li an artotype; and in the
Transact - of the New JTorls Academj of Sciences, volume xii, March, 1893, a memoir, by Pro-
fessor ll. L. Fairchild, republished by the Scientific Alliance of New York, March, 1893. \
memorial, bj Professor J. J. Stevenson, appears in the American Geologist for July, 1893, with a
revised chronologic bibliography, by J, !•'. Kemp.

W. M. DAVIS — MEMORIAL 0¥ J. II. CHAPIN. 407

descendant in the eighth generation of .Samuel Chapin, who came from
Wales to Dorchester, Massachusetts,, in 1636 or 1637, moving to the out-
lying settlement of Springfield, Massachusetts, in 1842. II is father was
Gustavus W. Chapin, of Cooperstown, New York ; his mother, Mary
McNanghton, of Ohio. One of the family of nine children of a hard-
working farmer, Dr Chapin showed a characteristic American spirit,
being a self-supporting student in his youth and an active worker in
varied directions during his maturity. He was graduated at Lombard
college, Galesburg, Illinois, in 1857, and spent a time there in teaching
mathematics and natural science; but he soon turned toward the minis-
try and occupied Universalist pulpits in Illinois for several years. In
L857 he married Helen M. Weaver, who died in 1871, leaving a daugh-
ter. During the later years of the rebellion he was actively and suc-
cessfully engaged in California in raising funds for the Sanitary Com-
mission.

It is not until 1871 that Dr Chapin's attention was especially directed
toward geology. It had been previously a subject of general interest to
him, but on accepting the chair of geology and mineralogy in the St.
Lawrence University in northern New York his thoughts were more
turned toward our science. Detween 1873 and 1885 he also held the
pastorate of the Universalist church at Meriden, Connecticut, where he
resided the greater part of the time, his duties at the St. Lawrence
University requiring but the smaller part of the year. In 1875 he was
called to the presidency of his alma mater at Galesberg, Illinois, but felt
unable to accept the position.

At Meriden, in 1878, he married Kate A. Lewis, daughter of Honorable
Isaac C. Lewis, prominently connected with the business development
of that busy city. His travels abroad and his lectures at home during
the past twenty years led to the publication of several volumes of gen-
eral interest. In 1889 he was elected to the Connecticut legislature,
where he was active in introducing a bill for a state topographic survey
similar to the surveys previously established in Massachusetts and
Rhode Island. He was appointed one of the three commissioners to
superintend the prosecution of the survey, and through his interest in
the work he made it widely known to the people of the state. The
schools of Meriden had his close attention, and the high school was
his particular care. He was closely identified with the Meriden Scien-
tific Association, an active local institution, of which he has been presi-
dent. He frequently took part in its meetings and excursions, his
interest being aroused in particular by the ancient volcanic phenomena,
of the district. His death was deeply felt by the community in which
he was so actively engaged.

tOS PROCEEDINGS OF OTTAWA MEETING.

The following is a list of the geologic writings of Dr Chapin :

BIBLIOGRAPHY.

The Creation and the early Development of Society : New York, L880, 276 pages-
The hanging Hills; The Trap Ridges of Meriden; Notes of Africa : Trans. Meridm

Sci. Assoc.
The topographical Survey of Connecticut: Trans. Meriden Sci. Assoc, January,

1890, p. 7.
Oycadinocarpus chapini : Trans. Meriden Sci. Assoc, .January, 1891, i>. I.
Some geological Features of Meriden: Trans. Meriden Sci. Assoc, January. 1891,

p. 4.
Magazine articles <>n Science and Religion and Genises and Geology.
A Year's Progress in Science : Meriden Daily Republican, February 9, L892.

The President, following the reading of the memorials, declared the
morning session adjourned.

The Society reassembled at 2 o'clock p. m., and the reading of papers
was declared in order.

The first paper upon the printed program was, —

ON THE COALS AM) PETROLEUMS OF THE CROW'S MOST PASS. ROCKY

MOUNTAINS

BY A. E. C. SELWYN

Remarks were made by the President and I. C. White.

The second paper was —

ON THE GEOLOGY OF NATURAL GAS AM) PETROLEUM IX SOUTHWESTERN

ONTARIO

BY H. I'. II. BRUMELL

Remarks were made in discussion by Dr I. C. White, who said :

That .Mr Brumell's paper was confirmatory of Professor Edward Orton's conclu-
sion that the limestone, when a repository of oil or gas, is dolomitic and porous,
and that the probable reason why the Dundas anticlinal contains no gas is because
the Trenton limestone there is not dolomitic.

Mr II. M. Ami said:

That the Trenton is throughout not dolomitic; that the dolomitic layers below
are of the Calciferous.

J. W. DAWSON — FOSSIL SPONGES. 109

Another paper by the same author:

NOTES ON THE OCCURRENCE OF PETROLEUM IN GASPE, QUEBEC

BY II. P. II. BEUMELL

These two papers are printed as pages 225-244 of this volume.

On account of the absence of the author the following paper was pre-
sented by title :

SOME FEATURES OF THE PHOSPHATE-BEARING ROCKS OF OTTAWA COUNTY,

PROVINCE OF QUEBEC %

BY ELFRIC DREW IXGALL

In the absence of the author the next paper was read by F. P. Adams:

NOTE ON FOSSIL SCONCES FROM THE QUEBEC CROUP (LOWER CAMBRO-
SILURIAN) AT LITTLE METIS, CANADA

BY J. WILLIAM DAWSON

[Abstract]

The object of this note was to introduce to the Society some specimens and a
photograph in illustration of a very remarkable and interesting discovery of
Lower Paleozoic sponges, made accidentally in 1887 by Dr B. G. Harrington,
F. G. S., and followed up by the writer.

In two or three thin bands, in black shales belonging to a markedly unfruitful
portion of the Quebec group, there occur a number of fossil sponges perfectly
flattened and with their originally silicious skeletons replaced with pyrite. They
thus form very delicate tracery on the surfaces of the shale. By careful quarrying
in these beds there were discovered up to 1889 thirteen species, which were de-
scribed and figured by the author and Dr Hinde, of London, in the Transactions
of the Royal Society of Canada for that year. Six of these belong to the primi-
tive genus Protospongia of Salter, and of most of these we have the entire forms,
showing their oscula, protecting spicules and anchoring rods, details which were
previously unknown. One species belongs to the genus Cyathospongia of Walcott,
previously known in the Utica shale. Another, cylindrical and curiously hispid,
has been placed by Hinde in a new genus Acanthodktya. Another appeals to be-
long to genus Hyalostelia of the same author. Three others, which seem to have
simple and not hexactinellid spicules, have been placed in the genera Sasiothrix
and HalichondrUes. The thirteenth lias not yet been named, being imperfectly
preserve 1.

Since 1889 the excavations have been continued, but until the present year with
the result only of finding additional specimens of the species already known. Last
summer, however, the author was so fortunate as to discover a very large and re-
markable form, of which a photograph was exhibited, the original slab, now in

410 PROCEEDINGS OF OTTAWA MEETING.

the Peter Redpath Museum of McGill University,, being too fragile to admit of
carriage. This new species m«st have been of sack-like form and as much as
fourteen inches in diameter. Its walls consist of rhombic meshes about half an
inch wide These meshes are made up of delicate spicules loosely twisted together
and apparently branching at the angles of the meshes. They seem to have been
filled in and covered with small cruciform or simple flesh spicules which toward
the sides conceal the meshes of the framework. The hair of the specimen and its
anchoring rods are wanting, but on the same surface are numerous fragments of
anchoring rods which would seem to have belonged to this species. They arc
composed of many long, slender spicules similar to those of the body, but closely
twisted so as to form a rope or cord, on which are placed minute tubercles or flat
projections, so as to give greater holding power. Tins remarkable sponge is prob-
ably the largest and most complex yet found in formations of so great age. Dr
Ilinde, the author of the British Museum catalogue of fossil sponges, has kindly
undertaken il!s detailed description, and proposes to place it in a new genus, Par
lawsaccus.

It was further remarked that the discovery of so many species on what repre-
sents a single sea bottom illustrates in a remarkable manner the abundance of
sponges at this early date, and shows how much may be learned by following up
productive beds in the older formations, in which it often happens that greal
thicknesses of rock are unproductive of fossils.

The only other fossils associated with these sponges are a species of Linnarssonia,
L. (Obolella) pretiosa of Billings, -and a slender, branching fucoid {Buthotreplm per-
gracilis). In neighboring sandstone beds there are fragments of Retiolites cusiformia
of Hall, and the curious' radiating markings known as Astiopolittion, along with
impressions of worm-burrows.

Remarks were made by II. M. Ami.

The following two papers were read by the author :

NOTES ON CAMBRIAN FOSSILS FROM THE SELKIRKS AND ROCKY MOUNTAIN

REGION OF CANADA

BY HENRY M. AMI

ON THE POTSDAM AND CALCIFEROUS TERRANES OF THE OTTAWA PALEOZOIC

BASIN

BY HENRY M. AMI

Remarks upon the subjects of these papers were made by C. II. Hitch-
cock, A. R. C. Selwyn :m<\ C. R. Van Hise.

The next communication was entitled :

NOTES ON THE DEVONIAN FORMATION OF MANITOBA AND THE NORTHWEST

TERRITORIES

BY I. I". WHITEAVES

W J MCGEE — A FOSSIL EARTHQUAKE. 411

The following paper was then read :

DISTINCT GLACIAL EPOCHS AND THE CRITEETA FOR THEIR RECOGNITION

BY R. D. SALISBURY

During the animated discussion which followed the reading of this
paper remarks were made by W J MeGee, C. H. Hitchcock, Warren
Upham, Robert Bell, B. K. Emerson and the President. The paper is
published in full in The Journal of Geology, volume i, pages 61-84.

The last paper of the afternoon session was —

PLEISTOCENE PHENOMENA IN THE REGION SOUTHEAST AND EAST OF LAKE

ATHABASKA, CANA I >A

BY .1. B. TYRRELL

Remarks were made by C. H. Hitchcock, Warren Upham and Robert
Bell.

Announcement of the lecture in the evening was given, and the Society
adjourned.

Evening Session of Wednesday, December 28

The Society was called to order at 8 o'clock in the Normal School
auditorium. A lecture was given upon the following subject :

A FOSSIL EARTHQUAKE
BY W I MCGEE

lAbslract]

With a single exception, the traveler by steam-packet on the lower Mississippi
funis the river flanked by alluvial hanks so low that during great freshets they
are overflowed all the way from Cairo to the Gulf, save where protected by natural
or artificial levees. The exceptional locality comprises nearly all of Lake county,
Tennessee, and a considerable area in Missouri, on the opposite side of the river.
This area, which is some 20 miles in mean diameter, bulges upward in the form
of a low dome, 20 or 25 feet above the general level of the alluvial plain. East of
it lies Reelfoot lake ; west of it the "Sunk country" of southeastern Missouri and
northeastern Arkansas, and through its erest the Mississippi has cut a meandering
trough. When the surface of the dome is examined it is found to he scored by
broad trenches like the channels of waterways; moreover, these trenches are
Hanked by natural levees so characteristic of the Mississippi flood-plains that they
are at once recognized as bayous from which the waters have been removed. The
structure of the dome is revealed in the channel of the Mississippi. Tt is com posed
of a sheet of alluvium, ll) to .'!() feet thick, identical in character with the modem

L XI -Bui. i.. (ion,. Soc. Am., Vol. I, 1892.

412 PROCEEDINGS OF OTTAWA MEETING.

river deposil flooring the entire flood plain, and unconformably below lies the
dense, tenacions blue or greenish Port Hudson clays, which underlie the flood plain
throughout. Thus the structure is similar to that of other parts of the "Delta."
save thai the deposits lie 20 or 25 feet higher.

The configuration and composition of the dome indicate that it was originally a
part of the broad flood plain extending from the mouth of the Ohio to the Gulf,
and its exceptional altitude and general conformation suggest a localized uplift.
Moreover, several of the dry bayous enter Keelfoot lake squarely or obliquely, and
when this occurs there is no trace of delta-building, and both channel and natural
levees may be traced for long distances in the lake; indeed, for some distances
they may be traced throughout their extent and found to connect in the form of a
fairly definite drainage system. This absence of deltas indicates that the uplift or
deformation occurred suddenly. Furthermore, it is found that while great cypresses,
Sycamores and poplars, sometimes two or three centuries old, grow over the gen-
eral surface of the dome, no trees older than seventy or seventy-five years grow-
within the unoccupied bayous; from which it maybe inferred that the uplift
occurred at least seventy or seventy-rive years ago, and probably not much earlier.

Reelfoot lake is a shallow water-body of irregular form, perhaps live miles in
average width anil twenty miles in length from north to south, lying between the
Lake county dome and the base of the upland scarp, a dozen t<> a score of miles
east of the river. Its depth increases very gradually from its western margin
nearly to the eastern shore, where at low water its depth is twenty or thirty feet.
At high water on the Mississippi its depth is some twenty feet more, since it then
becomes part of the general flood by which the Lake' county uplift is transformed
into a double island. The lake is not an uninterrupted sheet. Here and there,
particularly toward the western side, groves of sickly cypresses spring from its
bottom and half shadow- the water surface with puny branches and scant foliage,
and here and there throughout all portions of the water body, save in the channels
of the old bayous, gaunt cypress trunks with decaying branches stand, sometimes
a dozen to the acre, numbering many thousands in all. Moreover, between the
decaying boles, rising a score toa hundred feet above the water, there are ten times
as many stumps, commonly of lesser trees, rising barely to low-water level. Now.
while the subsurface structure beneath Keelfoot lake is not revealed, the phenomena
of the lake grade into the phenomena of the dome. The lake bottom is meandered
by waterways whose combined channels and natural levees prove them to be bayous

similar to those of the Mississippi H 1-plain; along and between the bayous

cypress stumps and boles are scattered just as they are distributed over much of the
modern flood-plain, and dry bayous and drowned swamps alike indicate that the
land beneath Reelfool lake was depressed. Moreover the transformation of the area
from land to lake without filling the old bayous by sediment indicates that the de-
pression occurred suddenly. Furthermore the presence of the cypress stumps and
trunks, particularly in the deep portions of the lake where the drowning must have
been complete, indicates that the date of the subsidence was not remote.

The upland scarp overlooking the Mississippi flood ['lain on the east, from Baton
Rouge to the mouth of the Ohio, is everywhere mantled by loess or a loam of
closely related character, and the mantle, as well as the underlying rocks, is deeply
scored by erosion. Accor lingly the upland margin is made up of steep salients and
cusps and narrow divides separating a myriad ravines. Now, on approaching the
Keelfoot country from the north or the south, certain minor topographic features

W .1 MCGEE — A FOSSIL EARTHQUAKE. 413

appear and finally culminate in that part of the scarp overlooking the lake. The
narrowest divides are longitudinally cleft by trenches yards in width and often
several feet in depth; the steeper outlying. cusps are divided by similar trenches,
and frequently the salients are cleft by such trenches cutting across their steeper
slopes or radiating in three <>r four lines from the apex. Furthermore, along the
face of the scarp opposite the lake, ancient landslips, with their characteristic
deformation of the surface, are found in numbers, and over the landslips and along
the sides of the trenches on the summit trees are frequently thrown out of the
perpendicular. These features suggest a sudden and violent movement by which
the highly unstable topographic forms of the upland scarp were in part broken
down arid thrown into more stable positions. On examining the inclined trees it
is usually found that the great holes two or more centuries old' are inclined from
root to top, though the younger trees of seventy or seventy-five years usually stand
upright, and that the trunks of a century to a century and a half in age are com-
monly inclined near the ground, but are vertical above. Thus the forest trees flank-
ing the fissures and clothing the scarp give a trustworthy and fairly accurate date for
the production of the minor topographic features — a date determined by much
counting of annual rings to lie between seventy-five and eighty-five or ninety
years ago.

While in general the flood-plain of the Mississippi is essentially alike in compo-
sition from Baton Rouge to Cairo, a minor distinction is found over the Lake
county dome and in its vicinity: The flat-lying alluvium is sometimes interrupted
by irregular ridges of gravel and coarse sand, sometimes by double ridges with
irregular trenches between; and now and then elongated mounds of similar gravel
and coarse sand occur, either isolated or in lines. When in cultivated lands, the
ridges and mounds are reduced but give character to the soil throughout entire
fields ; but when in woodland, they affect the forest to the extent that the larger
trees along their flanks are frequently thrown out of the perpendicular as are the
trunks of the upland, while only young trees about seventy-five years old and less
grow in the trenches.

Now it is conceivable that areas may be lifted like the Lake county dome or
depressed like Reelfoot lake by gentle diastrophic action ; it is conceivable even
that a group of contemporaneous landslips and fissures in a hilly scarp might he
developed by a variety of causes or movements coinciding fortuitously; but the
gravel ridges and mounds of the flood-plain are homologous with the craterlets,
sand spouts and fissures produced by earthquakes, and they are unlike phenomena
produced by any other known cause. Moreover the landslips and trenches of the
scarp are more perfectly and simply explained as the product of an earthquake
than in any other way. Again, the depression of the land beneath Reelfoot lake
is analogous to surface movements known to be produced by earthquakes; and it
might be shown through the application of the principle of isostasy that the uplift
in the center of the Mississippi lowland with the depression on both flanks toward
the more heavily loaded uplands, is mire readily explicable as an earthquake
product than in any other way. Accordingly the assemblage of phenomena may
he explained on the hypothesis of an earthquake of great severity, and cannot
well be explained on any other hypothesis. Thus the peculiar features of Lake
county, Tennessee, and contiguous territory, may justly be regarded as a physical
record of a great earthquake, the date of which is lixed by attendant phenomena
at from seventy-five to eighty-five years ago.

Ill PROCEEDINGS OF OTTAWA MEETING.

Assuming the verity of the hypothesis, one out of its many consequences may
be considered. The Lake county dome lies athwart the course of the Mississippi,
which is here well out in the flood-plain; so that, if the lifting was effected sud-
denly, the flow of the river must have been obstructed. Now the declivity of the
lower Mississippi is so slight and the land so low that the back water due to any
obstruction spreads over an enormous area and reaches a vast volume ; moreover,
under the hypothesis, the Reelfoot lake depression was formed contemporaneously
and the lake must have been filled by the water of the river taken not simply above
the obstruction lad (by reason of geographic relations which need not be set forth in
detail) from many miles above, ('. e., at what is now the site of Hickman. Accord-
ingly it may be considered certain that an immediate effect of the earthquake
must have been a reversal of the flow of the Mississippi about what is now the
the northern extremity of Lake county, at least for many hours.

There are voluminous, though somewhat vague and little known, records of a great
earthquake centering about the Spanish settlement of New Madrid, in southern
Missouri, beginning near the end of L811 and continuing with gradually diminishing
intensity through the succeeding year and most of 1813. These historical records
embrace a classical memoir by Dr S. L. Mitchill; an account by a kinsman of the
eminent professor of geology in Harvard college; a detailed paper in the American
Journal of Science, by Louis Bringier, a reputable engineer of New Orleans; de-
tailed descriptions in the ephemeral press and in the books of the day ; an elaborate
description by the geographer Flint; a careful and extended statement by Sir
Charles Lyell ; and an unpublished circumstantial account by a grandfather of the
writer, who resided in western Kentucky throughout the entire earthquake period.
From these various accounts, especially that of Mitchill, it can be shown, in so far
as historical records are trustworthy, that the New Madrid earthquake was one of
great severity and was unparalleled in extent ; it was felt from New < Means on the
south to Fort Dearborn (Chicago) and Detroit on the north, and from Washington
and Charleston on the east as far westward as explorers had then penetrated, thus
affecting fully one-third of the area of the United States or not less than a million
: quare miles.

For various reasons the historical records of the New Madrid earthquake have
been looked upon with distrust, ami a communication has been laid before one of
the leading scientific societies of the country by an eminent savant for the purpose
of proving that no such earthquake ever occurred. One of the reasons for the dis-
trust of the records was the allegation by Shaler, by Bringier, and by nearly all
contemporary witnesses that the flow of the Mississippi river was changed, and
that it ran upstream for hours ; another reason for distrust was found in the oft-
repeated allegations that during the tremor the earth opened and fountains of water
flowed from the fissures, bringing up great quantities of sand and gravel (as well as
"coal" and the type specimen of the now well-known Ovibos cavifrons), from un-
known depths; hut the latter allegations are in perfect accord with recent observa-
tions on earthquakes, notably, those of Charleston and Kach and Cachar, while
the reversal of the flow of the Mississippi is unmistakably recorded in the present
physical features of the region, for the summit of the Lake county dome is less than
a score of miles from the still existing town of New Madrid.

The lecture was illustrated by lantern views. In moving and second-
ing a vote of thanks to the lecturer addresses were made by Sir .lames

REPORT OF COMMITTEE ON PHOTOGRAPHS. 415

Grant and Sheriff Sweetland. Following the adjournment an informal
reception was given the Society.

Session of Thursday, December 29

The Society was called to order by President Gilbert at L0.30 o'clock
a in.

Mr J. S. Diller read the report of the Committee on Photographs,
which was accepted by consent. It was voted to continue the commit-
tee (J. F. Kemp, \Y. M. Davis, J. S. Diller) and to appropriate fifteen
dollars ($15.00] for the use of the committee during the next year.
The report is ;is follows :

THIRD ANNUAL REPORT OF THE COMMITTEE ON PHOTOGRAPHS

During the year 105 photographs have heen presented to the Society, and the

collection now numbers 740. In the register the donors' numbers are given in
parentheses for the convenience of those who may wish to purchase photographs.

The collection remains with the secretary of the committee, Mr J. S. Diller, at
the United States Geological Survey, Washington, I>. ('., where it is open to the
examination of members of the Society. During the year it lias been examined
by a number of members and many photographs have been ordered for educa-
tional institutions.

The collection was exhibited at both the Rochester and Ottawa meetings. On
this account the expenses of the committee were a little more ($11.67) than last
year, hut as the amount appropriated for the use of the Committee was §15.17,
there remained at the close of the annual meeting a balance of $3.50.

The committee solicits contributions, such as are indicated in previous reports.
Contributions may be sent to Professor J. F. Kemp, Columbia College, New York
city; Professor W. M. Davis, Harvard College, Cambridge, Mass., or to Mr J. S.
Diller, U. S. Geological Survey, Washington, D. C.

Register of Photographs received in 1892

Photographed and Donated by II'. //. Jackson, Denver, Colorado

Numbers 040 to 650, inclusive, size, 21 x 16 inches ; price, mounted, $2.50; un-
mounted, $2.00. Discount of 25 per cent on orders of $50.00 or over. Lantern
slides from all negatives, 50 cents each. Dour slides from same negative, 30 cents
each.

636 (1632). Grand canyon of the Colorado. Size, 21x71 inches; mounted, $17.50;

not mounted, si;>.00.
637(1008). Pike's peak from the Garden of the Gods. Size, 20x43 inches;

mounted, $12.00; not mounted, $10.00.
638 (1098p). Yellowstone canyon and falls. Size, 19 x 44 inches ; mounted, $12.00;

not mounted, §10.00.

I1C PROCEEDINGS OF OTTAWA MEETING.

639 L661p). Mammoth hoi springs; Cleopatra and Jupiter terraces. Size, L7x38

inches; mounted, $7.50; not mounted, $6.00.

hid | L095). Yellowstone canyon.

c»41 (1657). Pulpil terraces; Mammoth hot springs.

642(1105). Old Faithful; a geyser in action,

613(1106). The " Castle " geyser and Crested spring; Yellowstone National park.

644(1656). [ndexpeak; Wyoming.

i,i", L669). Fremont's peak and lake ; Wind River mountains, "Wyoming.

646 | L667 I. Teton range ; from the east.

647 (1666). Teton range; from Jackson's lake.
648(1653). Cloud peak; Big Horn mountains, Wyoming.

649 (1651). Matteo teepee, or Devil's tower.

650 (1344). South dome; from Glacier point.

Photographed and Presented by Professor H. F. Reid, Casi School <>r .\/i/>li"l »;,,/,-,,

i 7, ,-, /ro/'/. Old >

Size. •")', x8 inches. Copies of these photographs furnished to membersof the
Geological Society only at the following rates: Unmounted, 20 cents; mounted,
25 .-cm-: by Frank II. Stoll, 106 Euclid avenue, Cleveland, Ohio. Orders must
include Mr Reid's numbers, which are given below in parentheses.

(ill (258). Glacier draining into Tidal inlet.

* ■", u (259 . Mountain near Tidal inlet.

300). Muir -lacier from altitude of 2,003 feet ; looking eastward.

654 (303). Mount Case.

i'm") (305). Mount Young.

656 (310). Large iceberg discharged from Muirglacier; about 100 feet out of water.

657 (312). Muirglacier; from Caroline shoals.

658 -".11 . Muirglacier; from Sebree island.

659 318). Mountains at the head of Geikie inlet.

660 330 . Mount Wright; from Sebree island.

661 (333 . Rounded limestone on Drake island.

662 (.'!47j. View over Hugh Miller inlet.
653 348). View over Hugh Miller inlet.

664 (354). Geikie glacier ; Hugh Miller inlet.

(if,;) (362 . Mountains between Tidal and Queen inlets; from across the haw look-
ing northeast.
666 361 . View in Hugh Miller inlet.

667(371 . First northern tributary of Muir glacier ; from I".

668(379). Western tributary of Muir glacier ; from 1'.

669 380). Mount Wrighl : from I".

670 i 381 i. Muir glacier ; from I'.

671 ^>s"' . Junction of Girdled with Muirglacier.
672(386). Junction of Girdled with Muirglacier.
673(387 . Looking down Endicott valley.

i ;7 J (389 . Junction of Girdled with Muir glacier

675 :;'.»•") . Near head of Rendu inlet.

676(398). Mount Fairweather; upper part of Glacier bay.

REPORT OF COMMITTEE OX PHOTOGRAPHS. 417

077 (400). Upper part of Glacier bay.

078 (407). Looking up Rendu inlet; from Halfbreed island.
670 (400). Carroll glacier.

680 (410). Carroll glacier.

681 (413). Glacial scratches at the north end of Sebree island.
682(414). Muir glacier and Mount Case ; looking eastward.

683 (418). Stream terraces at end of Muir glacier.

684 (420). Ice front of Muir -lacier.

685 (434). Top of Mount Verstova; near Sitka.

Photographed and Presented by Professor C. 11. Hull, Minneapolis, Minn.

Size, 4' x 7| inches.

686 (1). Quarry in gneiss; Morton, Minn.

687 (2). Glaciated surface of gneissic rocks; Morton, Minn.
688(3). Exposure of quartzite conglomerate ; near New I'lm. Minn.

689 (4). The Dalles of the Saint Croix ; Taylor's Falls, Minn.

690 (5). Columnar structure of diabase; Grand Marais, Minn.

691 16). ".Basal conglomerate;" Taylor's Falls, Minn.
602 (7). The Potsdam sandstone ; < >sceola Mills, Wis.

693 (8). Fault in the Magnesian scries; near Hastings, Minn.

604(D). Contact of Trenton limestone and Saint Peter limestone; Minneapolis,

Minn.
695 (10). Displaced Trenton limestone; Saint, Paul, Minn.

Photographed and Presented by Mr J. Stanley-Brown, Washington, l>. C.
Views on the Seal islands, Bering sea. Size, 71, x 01 inches

696. Miak ; near Bogoslov, Saint Paul island.

697. Miak ; near Bogoslov, Saint Paul island.

Photograplied and Presented by Mr II. G. Bryant, Philadelphia, Pa
Kodak views of the Grand river and falls of Labrador. Size, 4', x :!:i inches

698. Rapids above the falls.

699. Brink of the falls.

700. The Grand falls of Labrador.

701. Looking up stream above the falls.

702. ( 'anyon below the falls.

703 (1). Cockle's Head ; near St. John's, Newfoundland.

704 (2). Outlet of Grand lake, Labrador.
705(3). Mountaineer Indian lodge On Grand lake.

700 (4). View looking down Grand river from lower falls.
707 (■">). Part of lower falls of Grand river.

418 PROCEEDINGS OF OTTAWA MEETING.

70S (6). " Dinner time."

709 (7). Rocky headland; Lake Wanakobou.

710 i si. Portaging around the Ninipi rapids.

711 (9). Camp at the head of navigation.
712(10). View on Lake Wa-na-ko-bou.

713 (1 1). Cascade near < Irand river above Mouni rapids.

714 (12). View on interior plateau of Labrador, showing glacial bowlders.

715 (13). Typical bowlder of the interior plateau.

Presented by V. S. Geological Survey

Photographed by W. P. Jenney

716. The anticlinal at the termination of the Ozark uplift in the northeastern cor-
ner of Indian Territory on Spring river about six miles south of Baxter,
Kansas; panoramic view of four <i x 8 inch photographs.

Photographed and presented by Ben Haines, New Albany, Tnd

Size 8 x 10 inches ; price, .">0 cents each
24 views of Mammoth cave and vicinity

717 (04). First saltpeter vats.

718 (05). < >ld saltpeter pipes.

719 (OS). Standing rocks.

720 (013). Stone cottage.

721 (014). Giant's coffin.

722 (017). Bottomless pit.

7i':; (022). The post-oak pillar.

724 (029). The arm-chair.

72.") (030). The elephants' heads.

726 (036). The Egyptian temple.

727 (037). Bacon chamber.

728 (055). Stalactites in Croghan's hall.

729 (056). End of the cave.

730 057). Star chamber.

7)51 (060). An alcove in Gothic avenue.

732 (065). Head of Echo river.

733 (0101 ). White's cave; Humbolt's pillar.
7I!4 (0106). White's cave; the royal canopy.
7:'-") (0124). Mammoth Cave hotel.
736(218). Wyandotte cave ; the throne.

737 (220). Wyandotte cave; Monument mountain and Wallace's grand dome.

738(235). Wyandotte cave ; Niagara falls (No. I).

739(524). Marengo cave; " Cupid's net."

740 (529). Marengo cave; Washington's plume.

A. P. LOW — GLACIAL GEOLOGY OF LABRADOB AND QUEBEC. 410
The scientific program was declared in order, and the first paper was :

NOTES ON THE GLACIAL GEOLOGY OF WESTERN LABRADOR A\~l> NORTHERN

QUEBEC*

BY A. P. I.oW

< 'mill ills.

Glacial Phenomena of (ho Region page 419

Pleistocene Changes of Level in Labrador 121

Glacial Phenomena ofth Region. — As may be supposed, there is no marked differ-
ence between the glacial phenomena of the interior of Labrador and those of
more southern Canada — they all point to a great mass of ice in motion. As the
central divide of the interior 1ms not yet been visited the conditions of the surface
there are unknown, but it will probably he found to differ but little from the por-
tions already explored. The watershed between the rivers (lowing into the gulf of
Saint Lawrence and those of Hudson hay acted as a dividing line to the direction
of the later ice movement. This height of land is a marked feature in the region
for over fifty miles to the north and south of Lake Mistassini, where it runs
roughly north-northeast and south-southwest, or parallel to the longer axis of that
lake. The country to the southeast of the divide is from 200 feet to 400 feet higher
than that to the north, the descent from the one to the other being quite sharp.
Near the summit of the slope toward the Saint Lawrence the liner material of the
till is abundant and the surface rock is not deeply grooved or striated. As the
slope is descended the stria' are more deeply marked and their course is very per-
sistent, being nearly due north and south to beyond Lake Saint John, where the
highlands of the Saint Lawrence border appear to have formed an obstruction to
the bottom of the moving ice ami caused it to change its course locally, so as to
pour out into the Saint Lawrence valley through any convenient pass between the
hills.

North of the divide all rock exposures are deeply scratched and grooved, the
direction of the striatum being from N. 30° E. to S. ;50° W., or parallel to the steep
escarpment of the watershed. Here the glacial action appears to have been much
more intense than on the southern slope; all the finer material being removed,
leaving only an innumerable number of bowlders to partly cover t he deeply grooA ed
rock. The only place where quantities of the finer drift material remain is along
the foot and sides of the escarpment, and this may be the remains of a lateral
moraine, but cannot be stated to lie such, as no detailed examination of it has
been made.

The great lakes Mistassini and Mistassinis and the other large lakes strung out
in line with them to the southwest lie parallel to the direction of the striae and
owe their origin to the action of the ice, which has scooped their deep basins out
of the comparatively soft, flat-bedded limestones of Mistassini and the altered
hornblende and chlorite slates of the lakes to the southwest. Leaving the granites,
gneisses and diorites to Conn the higher lands surrounding them.

Northward from Mistassini toward the East Main river the stria' hive every-

* Published by permission of the Director of the ■ ■< ologv il Survej of Canada
LXtl— Bum., o'i.'.i. Soc. Am., Vol, I. LS92,

420 PROCEEDINGS oF OTTAWA MEETING.

where a \. MO0 E. direction, but when that river is reached these arc found to be
partly obliterated by a newer set coining from N. 50° E. This direction of the
newer set changes slow !v to N. 60° E. as the river is descended, the older set being
seen from time to time on favorably protected ruck surfaces. A remarkable feature
of the country to the northward of Lake Mistassini is the number of low hills
made up wholly of rounded bowlders. These lie parallel to the direction of the
stria' and culminate in sharp, narrow ridges that slope at high angles on either
side. These bowlder ridges are at times connected with rocky hills, but more often
stand up independently.

On the Big, Great Whale and Clearwater rivers a similar condition of glaciation
is found, the direction of the stria' following the general slope of the country-
Along the Big river it is from N. 70° E. ; on the Great Whale from S. 70° E., and
alon.ii' the Clearwater from nearly due east,

( )n the coast of Hudson hay the strife do not run in any one direction, but con-
form with local slopes. Here as many as four sets of striae have been observed on
the rocks ; any or all of these may mark the direction of local glaciers found toward
the close of the period on the rocky highlands facing the hay.

The composition of the drift is largely local, hut bowlders from known localities
are at times found transported from fifty to one hundred miles from their original
sources. The limestones of .Mistassini are found over sixty miles to the south-
southwest of the nearest known bed. Bowlders of this limestone, along with
others of Huronian rocks, are not uncommon in the drift of the southern slope to
within a few miles of hake Saint John. As no areas of these rocks are known to
exist in the region south of the watershed, at some time, probably during the
period of greatest accumulation, the ice-cap must have moved up over the height
of land, carrying with it fragments of the rocks on the north side and scattered
them over the southern slope, where they are now found, over one hundred miles
from their known source.

On a hill some 300 feet above Clearwater lake a bowlder of Silurian limestone
was found. Tins tends to prove the previously supposed presence of a basin of
rocks of this age in the level country south of Ungava hay, as the striae show
that the bowlder must have come from that direction. A chain of islands extends
up the eastern third of .lames hay. These are undoubtedly of glacial origin and
are the remains of a terminal moraine. Although they have been submerged at
or subsequent to their formation they still preserve all the characteristics of such
an origin, and the action during submergence has only slightly altered their ex-
ternal structure. They rise in their highest parts from 150 to 200 feet above the
present sea-level and are wholly composed of unstratified till. Their surface is
uneven, being dotted with small rounded lakes and ponds, while the hummocks
of bowlders have been flattened out and settled into compact masses by the later
wave action. Their faces are cut into terraces, hut there are no stratified deposits
anywhere. This moraine marked the limit of the glacier at a halt during the
period of retrocession and was not the limit during the time of greatest glaciation.
Then the ice pushed down from the interior of Labrador, crossed Hudsonbay
and passed up over the low country on the western and southwestern side, and
probably crossed the watershed and descended into Lake Superior. Of this we
have evidence, in the direction of the stria? and the presence of Silurian and
I tevonian limestone bowlders in the drifts, to show that this was 1 he direction of
the ice-flow, a Ion- the rivers falling into the southern ami southwestern portious

A. P. LOW — GLACIAL GEOLOGY OF LABRADOR AND QUEBEC. 421

of James hay, the limestone being transported from the lower flat region about
the bay far inland over the higher interior Archean country.

The retrocession of the glacier from the island moraine to the mainland i.s
marked by the morainic matter that fills the bay inside the boundary of the outer

islands.

Pleistocene Changes of Level in Labrador. — At the close of the glacial period there
was a marked elevation of the western part of Labrador. The extent and limits
of this elevation can be traced by the deposits of stratified sands and clays that
now cover the lower margin of the peninsula. On the Rupert and East Alain
rivers these deposits are found a long distance inland. On the latter river con-
tinuous deposits are met with for one hundred and ten miles from its mouth, and
at that distance reach an elevation of 050 feet above the present sea-level.
Although fossil marine shells are only found for some forty miles from the sea,
there is no d6ubt that the beds farther inland are a direct continuation of those
holding fossils and mark the limits of the ancient sea-level. As the exploration of
the Big river was not continuous, it is impossible to say to what distance inland
the marine deposits extend. For the first forty miles from its mouth the river
flows between steep banks of clay, capped with sand holding numerous fossils.
On the Great Whale river stratified deposits extend inland a distance of thirty
miles to beyond the forks. Above this the river passes for several miles through
a deep narrow gorge on its way down from the interior plateau. Any stratified
deposits which might have existed in this gorge have been washed away, and the
only traces of such are isolated patches of fine sand clinging to the rocky sides in
protected positions. The highest of these are about 100 feet above the river or,
roughly, 000 feet above the sea. Terraces up to 300 feet elevation flank the rocky
hills in a number of places along the northern coast. At the mouth of the Clear-
water river on Richmond gulf a series of fine sandy terraces are seen, the highest
being about 300 feet above the water.

The first portage on the route from Richmond gulf to Clearwater lake passes up
a wide valley over old sea beaches facing the gulf; the highest of these on a level
with a small plain is 450 feet above the sea. Beyond this for ten miles up the
small stream followed by the route there are terraces cut in stratified clays and
sands that rise in the highest 160 feet above the river, or 075 feet above the present
sea-level. Beyond this line the surface material is unstratified till.

From the above it will be seen that the Pleistocene elevation of the western side
of Labrador was nearly uniform from the south end of Hudson bay to Richmond
gulf, with a maximum elevation of (175 feet toward the north.

According to Dr A. S. Packard,-- raised beaches and terraces are found along the
Atlantic coast from the strait of Belle Isle to Hopedale. These are seldom or
never more than 200 feet above the sea, or less than one-third of the elevation of
the terraces on the western side.

If the theory that the greatest elevation conformed with the areas of greatest
ice accumulation, the ice-cap on the western part of Labrador must have been
much thicker than that on tin; eastern portion. This agrees with the state of
glaciation observed by Dr Bell t along the northern Atlantic coast, where lie re-
ports that the upper parts of the high Coast range form sharp serrated peaks,
covered with undisturbed rotted rock, and that evidence of glacial action is only
seen in their lower valleys.

*The Labrador Coast, pp. 306-310.

t Report of Progress, Geol. Surv. Canada, L882-'83-'84.

Vl'l PROCEEDINGS <>i< OTTAWA MEETING.

The second paper read was ;

HEIGHT OF THE BAY OF FUNDY COAST IX THE GLACIAL PERIOD RELATIVE

TO SEA-LEVEL, A.S EVIDENCED BY MARINE FOSSILS IN TIIK

BOWLDER-CLAY AT SAINT JOHN, NEW BRUNSWICK

BY ROBERT CHALMERS

Remarks were made by Mr Warren Upham as follows:

These fossiliferous beds with till above and below them were doubtless formed
close tu the ice-front, which, as Mr. Chalmers has shown, probably rested on the
neighboring hills of this coast, temporarily receding to them and thence ^advanc-
ing a short distance into the sea. That the ice-sheet was near is implied by the
abundance' of the shells of Yoldia I L da) arctica, which is now found only in Arc-
tic seas and thrives best, according to Baron de < leer's observations in Spitzbergen,
near the mouths of streams of very silty water discharged from glaciers.

The paper is printed as pages 361-37' • of this volume.
The following paper was read by title:

THE ABANDONED STRANDS OF LAKE WARREN
BY ANDREW C. LAWSON

This paper is incorporated in the Twentieth Annual Report of the
Geological and Natural History Survey of Minnesota, 1891, pages 181—
239.

The next paper was read by the author, hut not submitted for publi-
cation:

THE PLEISTOCENE HISTORY OF NORTHEASTERN IOWA

BY W .1 MCGEE

In the discussion of the paper remarks were made by 11. D.Salisbury,
C. R. Van Hise, Warren Upham, Robert Bell, and Mr .!. M. Macoun, a
visitor. The paper is embodied in the Eleventh Annual Report of the
United States Geological Survey. 1889-'90, pages L89-577.

The last paper of the morning session was:

ESKERS NEAR ROCHESTER, NEW YORK
BY WARREN I 1'IIAM

This communication is published in the Proceedings of the Rochester
Academy of Science, volume ii. pages 181-200.

At the close of the reading of this paper a recess was taken until 2
o'clock p. m.

G. I-'. WRIGHT — POST-GLACIAL OUTLET l'Lo.M GREAT LAKES. 423

On reassembling at "2 o'clock the following communication was read:

COMPARISON OF PLEISTOCENE AND PRESENT [CE-SHEETS
BY WARREN ll'HAM

The paper provoked a spirited hut pleasant discussion, the chief point
of division being the evidence as to the existence of man in America
during glacial time. Remarks were made )>y \V .1 McCee, A. R. ( '.
Selwyn, G. F. Wright, R. 1). Salisbury and the author. The paper is
printed as pages 191-204 of this volume.

The next paper Avas as follows:

Till': SUPPOSED POST-GLACIAL OUTLET OK THE GREAT LAKES THROUGH
LAKE NIPISSING AND THE MATTAWA KIVER

I1Y (I. FREDERICK WRIGHT

During the early part of last September, in company with Judge C. C. Baldwin,
of Cleveland, D. C. Baldwin, of Elyria, and Professor Albert A. Wright, of Oberlin,
and while engaged in the work of collecting fragments of the rock in place along
the line of the Canadian Pacific railroad from the Sault Ste Marie to Ottawa to
aid in identifying the glacial bowlders of Ohio, we turned aside for a few days to
study the evidence which attracted our attention in support of Mr Gilbert's hy-
pothesis that upon the first melting back of the ice of the glacial period the main
part of the water of the great lakes ran for a, while from Lake Xipissing by way of
the Mattawa river into the Ottawa. This theory was, 1 believe, first presented by
Mr Gilbert at the meeting of the American Association for the Advancement of
Science at Toronto in August, 1881). The substance of his address upon that occa-
sion was published in the Sixth Annual Report of the Commissioners of the State
Reservation at Niagara (pages 61-84) and reprinted in the Smithsonian Report for
is; io (pages 231-257 \

The general facts suggesting such an outlet are those connected with the northerly
depression of land known to exist at the close of the glacial period, and revealed
in the familiar phenomena of the so-called Champlain epoch. The subsidence at
Montreal, as shown by the marine shells resting upon glacial deposits, was a little
over 500 feet, while in the valley of Lake Champlain it was considerably less, and
in the latitude of New York city very much le^s still, if it had not wholly disap-
peared. It is difficult to determine from direct evidence at hand what was the
subsidence in the region of the great lakes, though it is evident from Air [Jpham's
report upon the shore-lines of Lake Agassiz, from the investigations of Mr Gilbert
and Mr Spencer upon the raised beaches about Lake < hitario, and from the various
reports upon the old shore-lines north of Lakes Huron and Superior, that this dif-
ferential northern subsidence characterized the whole interior basin east of the
Rocky mountains. These facts, coupled with the known relative depression of
the col between Lake Nipissing and the Mattawa river, naturally created confi-
dence in Mr Gilbert's theory that the outlet of the great lakes by way of this col
was once a reality, for the difference of level between Lake Erie and the col at

424 PROCEEDINGS OF OTTAWA MEETING.

North bay, Ontario, is but little more than LOO feet, Lake Nipissing being, as we
make it, but (SI feet higher than Lake Huron, 66 feel above Jjsike Erie (water works,
south margin of North bay), and Trout lake, at the head of the Mattawa river,
but l'Dj feet above Lake Nipissing, while the col between is nowhere more than
about 25 feet above Trout lake A differential depression, therefore, of 1~>'» feet,
as between North bay and Niagara, would now divert the waters of the lakes by
the < Htawa river, while the passes between the Mattawa and Lake < mtario are all
of a considerably greater height. From these fads it was natural to expect that

such an Outlet existed.

We did not have time to trace the whole line of the supposed outlet, but the
following observations upon the local facts seemed to be sufficient to add greatly to
our confidence in Mr Gilbert's theory, if they do not, indeed, positively prove it.
The col between Lake Nipissing and Trout lake, extending from one lake to
another, a distance of two or three miles, is wholly occupied by a level swampy
tract, as already said, not more than 25 feet above Trout lake and unobstructed by
any continuous ridge of rocks or higher land. On the north this swamp is bordered
by an extension of an old beach-line of Lake Nipissing, constituting a clearly
defined terrace carrying a great abundance of well-rounded pebbles and extending
from lake to lake at a height of about 50 feet above the swamp referred to. This
beach borders the more elevated region which rises to the north. Upon the south
side of the passage between the two valleys the indentations are so extensive and
irregular that we did not have time to trace the corresponding shore line, but this
•would seem sufficient to show that the water of the lakes for sometime stood
between Lake Nipissing and Trout lake at such a relative level that if the way
down the Mattawa and Ottawa were free from obstruction it must have poured in
that' direction in torrential volume. If such a torrent poured down the Mattawa
the effects should show themselves in a pronounced manner in a bowlder terrace
at the junction of the Mattawa and Ottawa rivers, which is about 40 miles distant
(40 by railroad), and according to the railroad survey 95 feet lower in level, which
is about 80 above the river, making the difference of water levels (that is between
the top of the Nipissing-Trout lake terrace and low water at Mattawa) of about
225 feet (95 -f 50 -.- 80).

Upon going down to the mouth of the Mattawa river we found an enormous
bowlder terrace far exceeding our expectations, which it would seem difficult to
account for on any other theory than that of the temporary existence at the close
of the Glacial Period of Gilbert's supposed torrential current of water from the
Great lakes. The bowldery delta terrace begins on the south side of the Mattawa
about three-quarters of a mile above the junction of the rivers and extends a some-
what less distance down the right bank of the Ottawa. It enlarges about the
middle of this distance and pushes out as a bar almost entirely across the < Utawa
river, making deep slack water above and turbulent rapids for a long distance
below. The terrace in this lower angle over the space mentioned < onsists entirely
of bowlders and well-rounded pebbles, which completely cover the surface and
apparently form the whole body of the terrace. The bowlders range in size from

a few inches up to 30 feet iu diameter, and the terrace is level-topped, the height
above the river being, according to our estimate, about Ml feet. A short distance
back from the Ottawa riser there is a well-marked river channel cutting across that
portion of the deposit which projects as a bar into the Ottawa river. This is the
line of the flow of the .Mattawa river when it joined the ( Mlawa about a mile below

G. F. WRIGHT — POST-GLACIAL OUTLET FROM GREAT LAKES. 425

its present mouth. The bed is well-defined, with its bottom about 25 or 30 feel
above the present river and with bowlders of the largest size upon cadi side.

Upon the north side of the Mattawa river for a mile or more above its junction
there is a slender but well-defined terrace of the same height with that upon the
south side, but consisting of fine material, presenting an area, which has naturally
been chosen for the cemetery and for a race-course. On the south side also the
great bowldery delta terrace shades into liner material higher up the stream.

We followed up the Mattawa river a distance of about 8 miles, to the vicinity of
Eau Claire. Though not able to study the region so carefully as we would have
[iked, everything so far as we could observe was favorable to the theory of its
havingbeen the temporary channel of a great stream of water. Terraces exist here
and there, such as would be expected, and the descent of the channel at the portage
of Plain Champ would aid in producing that final plunge in the descending stream
required to produce the effects described at the junction a mile or more below.

The only theories worth considering in accounting for these phenomena are that
this collection of bowlders is of the nature of a moraine modified by temporary
local floods which came down the Mattawa upon the melting of the ice, and that of
Mr Gilbert, that the torrent of Niagara was for a time diverted down this trough.

The moraine theory would seem untenable from the position of the material.
It is not in position for a moraine moving down either the valley of the < Htawa or
of that of the Mattawa. It is in fact midway between the two, upon the lower
angle of their junction, and runs up the Mattawa valley in a way to indicate the
predominant influence of rushing water coming down that valley. The position

and character of the bowlder terrace and its relation to the terrace upon tl ppo-

site side of the Mattawa is strictly analogous to that which 1 have described* as
occurring at Beaver, Pennsylvania. The accumulation of bowlders is also strictly
analogous to that at Pocatello, Idaho, where the Port Neuf valley opens out into
the Great Snake River plain, and described by me on pages 235 236 of my recent
work, "Man and the Glacial Period." In the case of the beaver terraces we have
to account for them by the vast Hoods at the close of the Glacial Period, hut the
accumulation is as nothing in comparison with that at Mattawau. At Pocatello,
however, some time after my collection of the facts, the publication of Mr Gil-
bert's monograph upon Lake Bonneville made it (dear that the overflow of that
great lake led down the Port Neuf river, and that for a period of 25 years the
volume of the flow was comparable to that of the Niagara, and the results are, as
we have said, closely analogous to those at Mattawau and almost equal in their
extent. The further prosecution of inquiries through the whole length of the
valley of the Mattawa will, however, by some be thought necessary to complete
the verification of this theory ; but for one 1 expect, most confidently the evidence
will be forthcoming when attention is sufficiently directed to the region,

Professor Wright's paper was discussed by the President and by Robert

Bell. Dr Bell said:

I have been over the ground referred toby Professor Wright and Mr Gilbert. I

think Professor Wright's hypothesis interesting as a suggestion, but do not < -

sider that sufficient evidence has yet been offered to make it anything more than
that. The matter has not been sufficiently investigated to enable us to c e to

'■■ Bull. 58, U, S. Geoli Survey, p. 77,

1:26 PROCEEDINGS OF OTTAWA MEETING.

any acceptable conclusion. The whole course of the supposed outlet should be
examined before ii can be asserted that some objections fatal to the theory do nol
exist. The lines of bowlders to the northward of Trout lake, which have been re-
ferred to, might belong to moraines and nol to lacustrine terraces, which in any

ease would only prove a former eastward extension of Lake Nipissing.

Lake Huron is 582 feel above the sea and Lake Nipissing 637 feet, or 55 feel
higher. As the -round is low between Lake Nipissing and Trout lake, if Lake
Huron were only a little more than 55 feet higher than at present its waters might
have flowed down the Mattawa river at the time supposed by Professor Wright,
provided the relative levels of the whole region were the same then as now; but
this was unlikely to have been the case.

The valley of the Mattawa appeared to be only large enough for a river of the
small size of the present stream. At. the outlet of Trout lake the ground is high
and the river passes through a narrow opening. Again, from the outlet of Turtle
lake to Lake Talon the stream runs in a very contracted valley, which, speaking
from memory, 1 do not think gives indication of having afforded passage to a larger
body of water. Further down in the neighborhood of the south branch, the
Amable du Fond, the valley appeared to be quite contracted at several points.

I did not think that the bowlder-covered Held or plateau on which Mattawa vil-
lage is built could be cited as evidence in support of the present theory. Many
similar fields were to be found along- the Ottawa. The ridge of bowlders, pointing
northward, which juts out into the Ottawa river at the mouth of the Mattawa, is
of morainic origin and has probably been left, by a glacier which came down the
north-and-south stretch of the Ottawa jusl above this locality, or from one of the
tributary valleys on the opposite side of that river. Corresponding ridges of bowl-
ders, transverse to the current, formed similar points projecting into the ( Mtawa in
many places all along its course. Some of them ran completely across the bed of
the stream, as, for example, the one near Kettle island, only a. few miles below
Ottawa city, which at low water entirely obstructed navigation except at one nar-
row gap. All these I regard as having been left by glaciers descending from
the north-and-south valleys, which cut through the rocky hills to the northward
and fall into the Ottawa at right angles. I have described them in the chapter on
Surface Geology written for Sir W. E. Logan, in the Geology of Canada, lsu;;.

If, in comparatively recent geologic tines, the valley of the Ottawa river, from
the junction of the Mattawa to its mouth, had acted as a channel for the convey-
ance of a much larger body of water than the present stream, we should see abun-
dant evidence of the fact at many places on its course, but such evidence appears
to be wanting. Along its lower reaches for perhaps 200 miles above the mouth
clay banks of moderate elevation rise from high-water mark, ami from their brink
level tracts extend in many places for miles to the southward. The difference
between the annual high and low water marks in the* Htawa is a little over 20 feet.
I Miring the period of high water the river cuts into the fo.it of the clay banks and
so produces irregular widenings of the stream at the flood line. There is no sign
of any former erosion oft hese clay Hats by a higher level of water. In the vicinity
of the rapids ami falls of the Ottawa evidence also appears to be lacking of the
former passage of any larger body of water than al present.

In reference to the ten-aces around Lake Huron 1 will say. in connection with
the question, that along the north shore of that lake old beaches are to lie seen
almost everywhere up to a little over fifty feet above its present level , but that
they have only been noticed at greater elevations in a few places, such as near

G. M. DAWSON — GEOLOGY OP MI DDT: ETON l-I.AXH. 427

Parry sound, referred to by Mr Gilbert, and also at Wikwernikong on Manitoulin
island. Mure than forty years ago Mr Sandford Fleming, of Ottawa, wrote an ac-
count in the Journal of the Canadian Institute of the terraces around IJTottawasaga
bay, which had also been described by Professor Chapman; and I have made
profiles of the country to the southward of Georgian bay from lines of spirit-levels

which [ ran. These showed lacustrine terraces at almost every height up to s e

200 feet, but in the present state of our knowledge these facts might prove nothing
in reference to former outlets of Lake Huron, since the whole of the surrounding
area may have been slightly canted instead of having been uniformly elevated.

These were some of the unanswered difficulties which have presented them-
selves to my mind while Professor Wright was reading his paper, and I think
t hat, apart from the upsetting of all the calculations of geologists based on the
facts presented by the Niagara gorge, they are sufficient to justify me in not ac-
cepting the Professor's hypothesis until further investigations have been made.

The next paper was read for the absent author by Mr \V J Met ree :

ON CERTAIN FEATURES IN THE DISTRIBUTION" OP THE COLUMBIA
FORMATION ON THE MIDDLE ATLANTIC SLOPE

BY N. H. DARTON

Remarks upon the [taper were made by R. I). Salisbury, Warren
Upham and W J McGee.

In the absence of the author the next paper was read by R,. W. Ells :

NOTES ON THE GEOLOGY OF MIDDLETON ISLAM), ALASKA
KV GEORGE M. DAWSON

Middleton island is situated opposite Prince William sound, in that part of the
north Pacific which on some maps is named the gulf of Alaska. It is distant about
sixty-four miles from the mouth of the Copper river, the nearest part of the
mainland coast, and some fifty-five miles from the nearest points of any other laud
these being parts of the shores of Kaye island, Alaganik island and Montague
island. The three islands mentioned are all adjacent to the coast of the mainland
and separated from it by comparatively narrow waters. They lie in northeast,
north and northwest bearings respectively from Middleton island, which thus
stands alone and not far from the edge of the hundred-fathom hank or margin of
the continental plateau.

Mr J. M. Macoun was landed on this island on June 15, 1892, by 11. M. S.
Nymphe, and occupied the few hours at his disposal there in making a paced sur-
vey around the entire shore of the island, either on the beach or along the summit
of the low bordering cliffs when walking on the shore itself proved to he impos-
sible. He collected some specimens of the material of which the island is com-
posed and made a few notes upon it, determining the heights of the dill's, etc
by means of an aneroid barometer.

Mr Macoun does not profess to be a geologist, but on his return he submitted
his specimens to me, and it was at once apparent that these represented a true till
or bowlder-clay. The position of this island -lying as it 'Iocs so far to seaward
LXIT1 -Bull Geol. Soc. Am., Vol, I. 1892

428 PROCEEDINGS OF OTTAWA MEETING.

rendered this fact interesting, and some examinations of this bowlder-clay were
made. It is proposed to give the results of these examinations.

Knowing thai l>r W. II. Dall had visited the island some years ago, I wrote to
him, after having examined the specimens, to ask whether any account of its
geology had been previously published, and learned that a very brief note, based
«m I>r Hall's observations made in 1874, had lately been printed in Bulletin No. si
of the U. S. Geological Survey, pages 259 260. DrDall further obligingly supplied
me with an early copy of this publication, but the facts now ascertained appear
to throw a wholly new light on the structure and geologic age of the island.

Mr Macoun has furnished me with a very clear general description of the island,
based on his survey of it, which it is proposed to quote as introductory to the few
remarks based on my study of the specimens. lie writes :

" Middleton island is a little over five miles in length and a mile and a quarter in breadth at its
southern and wider end. At its northern extremity it narrows to a low sandy point, from which a
spit extends northward mure than two miles. This spit- is bare at low tide. For more than ten
miles off the southern end breakers are to be seen at all stages of the tide, and at low tide several
rocks or shoals show above water.

" \iiont the center of the west side of the island there is good anchorage; and from there to the
southern end there is no beach, the cliffs rising perpendicularly from the water to a height of
about 100 feet. From 100 to 300 yards back from the edge of the cliff the ground is level and
boggy, but it then rises abruptly between 25 and 40 feet. Tin-re is, in fact, here a distinct terrace
< ut I. aide in the material of the island, at a height of 100 feet above sea-level. The surface of the
island slopes gradually up from the eastern side to the high ground on the west, so that the
greater part of the water that falls upon the island runs off on the eastern side. Not even the
smallest stream is to he seen, but everywhere there is a constant trickling of water over the
el ills, and so soft is the material of which the island is composed, that on the eastern side it is being
gradually worn away and forms a steep incline from the summit to the water.

"The cliffs on this side are from 30 to 50 feet in height, and from their summit it can be seen
that the rock or general material of the island extends for some distance out from the shore, the
slope being much less after the level of the sea is reached.

"For about two miles along the eastern shore of the island the beach is strewn with pebbles and
small limestone bowlders. At the northern end and for about two miles along the northwestern
shore, the level rises but a few feet above the sea and the beach is composed of sand only. For
nearly a mile beyond this, toward the south, there are a good many bowlders along the shore, con-
sisting of granites, as well as black argillite. Just opposite the anchorage a hand of gravel not mere
than two feet in thickness was noticed running along the cliffs, and there may be more bands or

beds of the same material elsewhere, as no special importance was attached to these at the ti

and they were in (sequence not looked for or precisely noted, and none of the cliffs along the

southern half of the island were seen from the water. In my notes, the material of which the
island appears otherwise to be entirely composed was called a soft conglomerate, and the stones
contained in it are often as large as the head or larger.

"These seen along the shore appear to be derived, at least for the most part, from the wearing
away of the general material of the island, and vary in size from minute pebbles to large ones a
foot or more in diameter. This action must be very rapid, for when there is no true pebbly or
sandy beach, which is the case for about three miles ol the shore line, the waves wash in against
the actual Im^c of tl I ill-, which are in several places undercut. For about one and a half m ile-
al on g the middle part of (he island, on the east side, where the cliffs are from 10 to 25 feel high only,
there is no beach, hut the characteristic rock of the island extended here at half-tide from 10 to 20
yards out from the base of the cliff as a level floor. Tic sea was nearly calm at this time, but i he

water was discolored by earthy matter for some di si a IK a' from the shore ; and when wet. along the

edge of the sea the material is not only very slippery, but so soft that it may be rubbed away by

id,, ham I. A I ion i two miles from the northern end of the island one of the officers of the An ut ill,, ,

Who had I n walking along the shore and had come 1" a point he COllld not pass, had climbed ill'

ti,,. cliff by cutting places lor his feet with his knife, and when I reached this place I ascended to

the summit of the el ill' in the same way."

The component material of Middleton island, as represented by the specimens
brought back by Mr .Macoun. is. as already stated, a good typical bowlder-clay or

G. M. DAWSON — GEOLOGY OF MIDDLETOK ISLAM). 429

till, of rather dark, bluish-gray color, and somewhat unusually hard and compact.
It shows no sign of oxidation by weathering, and in the actual specimens received
is packed with small stones which vary in size from about an inch and a half in
diameter downward. These lie in all positions, ami there is no apparent stratifi-
cation or lamination whatever, though here and there small parts of the whole
appear to be more arenaceous than the rest. None of the stones are perceptably
facetted, nor on these seen can any distinct striation be observed. They are either
subangular or fairly well-rounded in shape, and the surfaces of a few of them are
so smooth as to be described as polished. It is apparent, in fact, that they repre-
sent water-rounded material.

The stones themselves consist almost exclusively of a hard, fine-grained, nearly
black material, which has not been microscopically examined in thin sections, but
appears to be undoubtedly a rather indurated argillite, resembling rocks seen by
the writer on several parts of the Alaskan coast, and which, merely from their
lithologic analogy with similar rocks on the better-known coast of British Colum-
bia, may represent what has been named the Vancouver Group, of Triassic Age.

The material also contains rather numerous fragments of shells, but all so much
broken in the specimens actually received as to be impossible of exact determina-
tion. One small piece of a ribbed shell appears, however, to represent a small
specimen of Cardium blandum. Several fragments, when microscopically exam-
ined, were found to be slightly rounded on the broken edges, while others were
quite angular. The whole mass of the clay is more or less calcareous, effervescing
freely when an acid is applied. Though very hard when dry, fragments broken
from the inner surfaces of the specimens of bowlder-clay when placed in water
partially break up, and with the aid of agitation and occasional slight pressure
applied to the harder lumps the whole was easily and completely disintegrated.

After removing the larger stones from about an ounce of the material, the residue
was subjected to a series of decantations at different intervals of time, by means of
which its constituents were separated in accordance with their size and specific
gravity, the modus operandi being the same as that employed in previous investi-
gations of bowlder-clays.*

A microscopic examination of the various samples thus obtained, showed this
bowlder-clay to comprise a considerable proportion of very fine silty matter, of
which the particles are nearly equal in size ; also some formless argillaceous matter
and a larger proportion of sand.

All grades of the sand proved to consist, to the amount of about one-third or one-
half, of partially or well rounded grains of the dark argillaceous rock above re-
ferred to, while the remainder was chiefly composed of quartz, generally glassy
and usually quite angular, though in part subangular or slightly rounded.

Two samples of this sand, of medium grade, were kindly examined in detail by
Mr \V. F. Ferrier, who states that, in addition to the argillite grains, the con-
stituents of the coarser of these samples are as follows, in order of abundance :

Medium coarse. — Quartz, feldspar (no striated grains were observed), magnetite,
a dark brown pyroxene (?), hornblende of various shades of green, brown mica,
(biotite ?) and a very few grains of titanite.

Medium fine. — The same materials, but with mica and hornblende rather more
abundant than in the last.

It may be added that the feldspar, pyroxene, hornblende, etc, are found in rather

* Hull. Chicago Acad. Sci., vol. i, no <

L30 proceedings of o'ttawa meeting.

small quantity, the impression conveyed being thai the sand cannot in any large
part be considered as directly derived from crystalline rocks, tn the coarsesl speci-
mens of sand resulting from the mechanical analysis of the bow Ider-clay the con-
stituent grains were easily separable by the unaided eye. ami among them were
found small fragments of shells and a number of foraminifera. Of these a small
collection was picked out and mounted, comprising about two dozen individuals,
and representing perhaps halt' the number present in about an ounce of the material.

These have been examined by Mr J. F. Whiteaves, who reports all the speci-
mens but three to be referable to PolystomeUa strkttopunctata, Frichtel and Moll,
w hile of the remaining specimens one is PulvLnulina karsteni, Reuss, another prob-
ably Nodosaria (Olandulina) laevigata, D'Orb., and the third not determinable, being
encrusted and badly worn.

The Polystomellse are rather small and depauperated in appearance, resembling
in this respect those found in the upper part of the gulf of Saint Lawrence/- where
the water becomes distinctly less saline than normal, but the collection so far ex-
amined is quite too small to warrant any theorizing on this fact.

In examining the medium grades of sandy material under the microscope numer-
ous fragments of sponge spicules were noticed. These weir generally straight, sim-
ple and tubular, but, so far as observed, never perfect. No diatomacse were seen,
though more extended and minute search might probably lead to this discovery.

In containing broken shells and other forms of marine life, the bowlder-clay
here described resembles that of some parts of the Queen Charlotte islands already
described by the writer, f The available evidence is, however, insufficient to en-
able us to refer the deposit of bow lder-clay of which Middleton island is composed
to its proper place in the sequence of events of the glacial period, for elsewhere on the
coast, and probably generally, there are two distinct bowlder-clays, which can only
he separated with certainty when both are seen. This bowlder-clay may have
been formed as a marine bank in proximity to the fronts of great glaciers debouch-
ing along the coast of the mainland to the northward, upon which detached ice-
bergs grounded from time to time.

The interstratilied layer or layers of pebbly material observed by Mr Macoun
might thus be explained, and it appears further to be borne out by the description
by Mr Dall, whose attention seems to have been more particularly directed to
evidences of bedding, and who writes:

"The island is composed of nearly horizontal layers of soft clayey rock, containing many peb-
bles and even bowlders of syenite and quartzite, some rounded and others of angular shape.
Above the claystone is a layer of gray sand covered with several feel of mould and turf."J

It is perhaps, however, on the whole more probable that this projecting mass of
bowlder-clay forming Middleton island represents a portion of a morainic accumu-
lation formed at or near the seaward edge of an ice-field derived from the adjacent
njainland, and which pushed southward or in a direction at right angles to that
of the average trend of the nearest continental coast.

The broken character of the shells seems to favor the belied" that the material
was ploughed up from the sea bottom and -really disturbed, rather than to show-
that it represents merely a bank upon which glacial debris was occasionally dis-
charged. Such a bank might probably be from time to time poached up by

*See I anadian Naturalist, L870. \>. itj.

: Quart. Jour. Geol. So :., M ly, 1831. K iporl of Progress, G sol, Surv: of Canada, l878-'79, p. 91 B,
»p. supra '-it., p. 260,

G.M.DAWSON — GEOLOGY OF MIDDLETON ISLAND. L3]

grounding ice, but this alone would appear to be scarcely sufficient to explain the
always broken appearance of the mollusks in the specimens actually to band.

The distance from the border of the mainland (about 55 miles) would seem to in-
dicate that it represents a portion of the morainic deposits formed at the outer edge
or along the retreating front of that part of the continuation of the Cordilleran
glacier which is believed to have occupied the highlands of the corresponding part
of the Alaskan coast during the first and most important period of glaciation.*

It will be noted that the island lies Opposite an extensive indentation in the
general coast line, marked by Prince William sound and also by the Copper River
valley, and it is therefore possible that the corresponding portion of the great
glacier here stretched further seaward than elsewhere. The water between the
mainland coast and Middleton island is not very deep, varying, according to the
few soundings shown on the chart, from 30 to 50 fathoms. It is therefore quite
probable that a glacier-sheet moving outward from the land may still have borne
upon the sea-bed with sufficient weight to produce the effects above alluded to,
even were the relative elevations of sea and land the same as those of to-day.
There is, however, so much reason to believe that very extensive changes in levels
have occurred in the region during and subsequent to the glacial period, that it is
not safe to assume that the relative levels were identical with those now existing.
It is reasonably certain that the island, composed of such relatively soft material,
and exposed as it is with few protecting beaches to the full force of denudation
exerted by a stormy ocean, has not for any very protracted period, from a geologic
point of view, stood at its present level. Mr Macoun's description of the western
side of the island in fact distinctly indicates the existence there of a well-marked
terrace, cut back at a height of al tout 100 feet above the present sea-level. Whether
this actually represents, in a modified form, that pause in elevation which the
coast further south seems to have experienced during the closing events of the
glacial period (there at an elevation of about 200 feet) t it is difficult to say ; but
it indicates, with scarcely any doubt, one stage in that general and last process of
elevation. The unoxidized character of the bowlder-clay itself seems to show that
it can never for a very prolonged period have been subjected to subaerial agencies.

In Dr Dall's observations on Middleton island, already quoted, the following

statements are in conclusion made :

"Below the sea-level some of the rock appeared to be quartzite in place an.d very hard. What-
ever its nature.it extends in reels and shoals to a distance of sevei-al miles from the island in
different directions. No fossils were found in the clay stone, but from its character it was suspected
to be post-Miocene and possibly Pliocene " J

Respecting the existence of a quartzite basis of the island, Dr I >all writes doubt-
fully as above, while Mr Macoun did not note any such underlying rock in follow-
ing the shores. It would appear to be very probable that the surrounding reefs
or shoals are merely the higher parts of a plane of marine denudation or banks
thrown up upon such a plane, which now surrounds this rapidly diminishing
island and corresponds with its original size under the existing relative levels of
sea and land in the region. As to the age of the material composing the island
itself there seems to be no room for doubt that this is Pleistocene and referable to
the Glacial Period.

* Later Physiographical Geology of the Rocky Mountain Region, etc : Trans. Royal Soc. Canada,
vol. viii, see. iv, map I.
f Ibid, p. 54.
I Op. supra cit., p. 200.

1:32 PROCEEDINGS OF OTTAWA MEETING.

Remarks upon Dr Dawson's communication were made by ('. \V. Hayes.
The next communication was read by title:

TWO NEOCENE RIVERS OF CALIFORNIA
BY WALDEMAR LINDGREN

The paper is printed as page3 257-298 of this volume.
The following paper was read by the author :

THE LAURENTIAN OF THE OTTAWA DISTRICT
BY ROBERT \V. ELLS

It was discussed by F. D. Adams, C. R. Van I rise, A. R. C. Selwyn and
the author. It is printed as pages 349-360 of this volume.

The last paper of the day was —

THE CONTACT OF THE LAURENTIAN AND HURONIAN NORTH OF LAKE HURON

BY ROBERT BELL

A full synopsis of this paper will be found in the American Geologist
for February, 1893, pages 135-136.

Before adjourning it was announced that the Fellows were invited to the
annual dinner of the Logan Club at the Russell house, Thursday evening.

Session of Friday, December 30

The President called the Society to order at 8.15 a. m.

The Auditing Committee reported that the accounts and report of the
Treasurer had been found correct. The report of the committee was
accepted and the committee discharged.

The following letter was read by the Secretary :

Boston Society of Xatckal History,

Boston, Massachusetts, December :: , 1892.

Dear Sir: I have the honor of extending the cordial invitation of the Boston
Society of Natural History to the Geological Society of America to hold its next
winter meeting in Boston, at our building. I am pleased to assure you that if the
geologists come to Boston one year from this time they will receive a cordial
welcome.

Most respectfully. William II. Niles, President.

To Professor II. LeRoy Fairchild,

Secretary of die Geological Society of America.

TITLES OF PAPERS READ BEFORE THE SOCIETY. 133

A telegram from Sir J. W. Dawson, the President-elect, in response to
one sent him notifying him of his election, was received, and read at a
later hour during the morning session.

The President announced that the summer meeting would be held at
Madison, Wisconsin, the precise date in August to be announced later.

The annual address of the President was read from the chair:

( '< (NTINENTAL PROBLEMS

BY G. K. GILBERT

The address is printed as pages 179-190 of this volume.
The first paper of the program was —

THE ARCHEAN ROCKS WEST OF LAKE SUPERIOR
BY W. II. C. SMITH

Mr Smith,* a member of the Geological Survey Department of Canada.
was introduced by R. W. Ells. The paper was discussed by ('. R. Van
Hise and A. R. C. Selwyn. It is printed as pages 333-348 of this volume.

The second paper was —

RELATIONS OF THE LAURENTIAN AND HURONIAN ROCKS NORTH OF LAKE

HURON

BY ALFRED 15. BARLOW

Remarks were made by C. R. Van Hise. The paper is printed on
pages 313-332 of this volume. It was read under the title "On the
Archean of the Sudbury mining District."

A recess was taken until 2 o'clock. When the Society reconvened the
following paper was read for the absent author by Mr W .1 McGee :

THE WORK OF THE UNITED STATES GEOLOGICAL SURVEY

BY J. \V. POWELL

The communication was illustrated by samples of the maps published
and projected by the Survey. Remarks were made by A. R. ('. Selwyn
and P>. K. Emerson. The paper is printed in Science, volume xxi,
number 519, pages 15-17.

*Soon after the adjournment of the n ting came the sad annoui menl of the death of Mr.

Smith. To his activity was in no small asure due the success of the Ottawa

indeed, his death may be said to have i n partly due to his persistent efforts, exerted even iu

the face of his physician's warning.

434 PROCEEDINGS OF OTTAWA MEETING.

The next paper was —

GEOMORPHOLOGY OF THE SOUTHERN APPALACHIANS
BY C. WILLARD HAYES VND M. B. CAMPBELL

Remarks were made by W -I McGee. This paper will be published in
tlif National Geographic Magazine.

The Society then, at 3.30 p. m., adjourned until the evening, in order
thai the Fellows might be able to accept the invitation to a reception
tendered the Society by Her Excellency The Lady Stanley of Preston,
at Government house, at 4 o'clock.

Evening Session of Friday, December 30

The Society was called to order at 8 p m. Mr F. 1). Adams in the chair.
The first communication was —

NOTES ON THE GOLD RANGE IN BRITISH COLUMBIA

BY JAMES MCEVOY

Mr McEvoy, who is a member of the Geological Survey Department
of Canada, was introduced by IT. M. Ami. Remarks upon the paper
were made by A. E. Barlow.

The second paper of the evening session was —

THE IMPORTANCE OF PHOTOGRAPHY IN ILLUSTRATING GEOLOGICAL

STRUCTURE

BY R. W. ELLS

The paper was illustrated with a series of large photographs, and was
discussed by B. K. Emerson, F. D. Adams and Mr J. Lainson Mills, a
visitor.

In the absence of the author of the following two papers, the first was
read by Mr Q. S. ( iiant and the second by Mr -J. S. Diller :

SOME MARYLAND GRANITES AND THEIR ORIGIN

EPIDOTE AS A PRIMARY COMPONENT OK ERUPTIVE ROCKS
BY CHARLES ROLLIN K'KVKS

These two papers were discussed by I'1- D. Adam-. They are printed
as pages 299-312 of this volume.

C. R. VAX [USE — HTJRONIAN VOLCANICS. 435

The next two papers were read by the authors, being, on account of
their relationship, placed in juxtaposition:

CKETACEOUS AND EARLY TERTIARY OF NORTHERN CALIFORNIA AND

OREGON

BY .!. S. DILLER

This paper is printed as pages 205-224 of this volume.

THE FAUNAS OF THE SHASTA AND CHICO FORMATIONS

BY T. \V. STANTON

This paper is printed as pages 245-256 of this volume.

President Gilbert assumed the chair, and the following paper was read :

THE HURONIAN VOLCANICS SOUTH OF LAKE SUPERIOR*

BY C. R. VAN IIISE

[Abstract]

South of Lake Superior are extensive areas of Iluronian nicks, consisting of a
succession of basic lava flows, with iriterstratified contemporaneous fragmentals.
Associated with these are occasional porphyries.

Petrographically the volcanic series includes porphyrite, augite-porphyrite,
amygdaloid, devitrified glass, flo wage breccia, and greenstone conglomerate. In-
cluded under the latter term are agglomerates, tuffs, mingled tuff and lava, and
true detrital conglomerates, the material of which is chiefly derived from the vol-
canic series.

The porphyrites and augite-porphyrites are fine-grained, dense, and frequently
show, when weathered, a very curious spheroidal parting; also at times they pass
into flowage breccias.

The amygdaloids vary from pumiceous or scoriaceous rocks into those in which
the amygdules are rare, until finally the porphyrites are reached. Like the porphy-
rites, they show at times a spheroidal parting or brecciation, and not infrequently
in the spheroidal phases, each of the spheroids is dense and noh-amygdaloidal on
one side and distinctly amygdaloidal upon the other. Moreover, the amygdal< tidal
portions are all on the upper sides of the blocks. It would seem licit while the
rock was still viscous it must have cracked, and that before solidification occurred,
in each block the amygdaloidal cavities rose to the upper part.

The amygdules are chlorite, feldspar, epidote, and quartz, including chalcedony
and jasper. In the more open amygdaloids the amygdules are sometimes as much
as 8 or 10 inches in diameter. The ferruginous quartz, known as jasper in these
amygdaloids, is so remarkably like the jasper of the iron-hearing formation south of
Lake Superior that it was at first thought that these are inclusions caughl in the
lava, but a closer study shows their undoubted amygdaloidal character, since the

♦ Published by permission of tic Director of the United 31 ilogiesil Survey.

LXIV— Bull, Grot,. Soc. Am,, Vol, i L892.

430 PROCEEDINGS OF OTTAWA MEETING.

amygdules arc found of all sizes down to ordinary ones and with all gradations in
color into the white chalcedony and quartz. As the chert and jasper formation in
one oft lie districts rests directly upon the amygdaloid it is believed that the jasper
of the ore formation and that in the amygdaloid are secondary rocks, formed
simultaneously, as has been advocated by Irving and myself in reference to the
major pari of the ore formations of the Lake Superior region.

The term greenstone-conglomerate, rather than agglomerate, is used because this
latter implies a definite theory of origin. A study of these rucks, in the field and
under the microscope, shows undoubted gradations from rocks which are true
detritals to those which are tnti's, from this to tuff and lava intermingled, and
then to tine lava Hows, which are often brecciated. Probably also some of the
rocks are true agglomerates, some of the elastics are undoubtedly sub-aqueous
ash-beds, from which there arc gradations into the true detritals.

The interstratification of volcanics and detritals, combined with the lithologic
similarity of the rocks, at once suggests a comparison between the Huronian vol-
canic series and tin' Keweenawan. There are, however, important differences.
The Huronian volcanics are for the most part Aery much more altered than those
of the Keweenawan. Many of thorn have been sheared, and they then pass into
crystalline greenstone-schists. The detritals, in common with the igneous rocks,
have also frequently been metamorphosed into mica-schists, hornblende-schists, etc.

These volcanic seriesare known at various places south of Lake Superior, hut the
most extensive areas are at the east end of the Gogebic series, west of Gogebic lake,
Michigan, and north of Crystal Fall, in the Michigamme district, Michigan, in
the < rOgebic area the volcanic -roup is 7,000 or 8,000 feet in thickness. The strata.
in approaching the volcanic center, both from the east and the west, take a sudden
swing to the south, showing a sinking of the formations about the volcanic foci, as
a result of the loading of the earth's strata by a mountainous mass of volcanic ma-
terial. Moreover, this great thickness of volcanic material stands as the equiv-
alent in time to the iron-bearing formation of the west, which is, upon an
average, not more than 700 or 800 feet thick. "We thus are able to compare in
this area the rate of deposition of a formation analogous to a limestone and a
group of volcanic strata. Also the district gives an excellent illustration of the
principle that in the pre-Cambrian rocks, lithologic character may be no guide as
to age, for within a few miles we have a simple sedimentary series passing laterally
into a volcanic series. If the two areas chanced not to be connected, there would
ajreal temptation to infer that they are not contemporaneous.

Remarks upon Professor Van Hises paper were made by W. H. ( '.
Smith and W -I McGee.

In the absence of the author of the following paper, it was read by
Mr W -I McGee:

ON TWO OVERTHRUSTS IX EASTERN NEW YORK*
BY N, II. DARTON

l.ast autumn I mapped the Helderberg and associated formations in New York
for the geologic map of that state now in course of publication. In the western
and central portions of the state these formations lie in the general, gently south-

* Extracted by permission from a report to Dr James Hall, State I logisl of New York.

N. II. DARTON — TWO OVERTHRUSTS IN NEW YORK.

-1 • > I

dipping monocline, but in their eastward extension to the vicinity of the Hudson
river they are traversed by small but steep and characteristic flexures of the north-
ern prolongation of the Appalachians. Davis - lias described two typical areas in
this flexed belt, and in a memoir "On the Helderberg and associated formations
of eastern central New York," to accompany the report of the state geologist for
1892, I shall describe the entire area from Schoharie to Ellen ville. It is the pur-
pose of this paper to exhibit two particularly interesting details of the structure
of the region: one an overthrust fault near Rosendale, in the great cement region,
and the other a composite overthrust west of South Bethlehem.

In Mather's report on the southeastern district of New York faults were proposed
to account for nearly every prominent topographic feature in his district, but I find
only a few faults in the Helderberg belt and these only of small amount and local
influence. Mather's report is very meagre of details regarding the structure of this
region, and his statements and sections are nearly all erroneous.

The relations of the overthrust near Rosendale are shown in the following figure :

Figure 1. — Cross-section of Ridge on south Side of Rondout Creek, at Rosendale, Ulster County, New

York, looking North.

The fault is on the eastern flank of the great corrugated anticlinal of the
Shawangunk mountains, which pitches northward in the vicinity of Rosendale
and involves the cement series and Helderberg formations. To the north the fault
extends across the creek, through the village and up a depression, dying out in
about two miles. To the south it soon runs out into the high, sand-covered terrace
lying east of the Shawangunk ridges. Its maximum displacement is about 200
feet, which it attains at the village of Rosendale. The details of the fault are finely
exposed in an abandoned cement quarry on. the slope just south of the creek, and
it is here that my section passes. The wedge of cement has been worked out for
a length of 200 feet and the fault plane is the hanging wall of the quarry. Many
minor features of slate wedges and crumpling arc not represented in the figure, bu1
I have shown at D a small wedge of grit which is faulted and cross faulted into the
main slate wedge at one point. The principal fault plane is along A-B, huf three
has been considerable movemenl along A-C, which has beautifully slickensided the
surface of the grit. Cross-faults and minor crumples are irregularly intermingled

-The Little Mountains east of the Catskills : Appalachia, vol. iii, p. 20. The Folded Helderberg
Limestones east of the Catskills : Harvard College, Bull. Mus. Comp. Zo61 , vol. 7, p. 311. Norn ion-
formity at Rondout: Am. Jour. Sei., 3d ser., vol, xwi. p,

438

PKOCEEDINGS QF OTTAWA MEETING.

in the displacement, and I could notworkoul their relations. The relations below
the cement wedge are not fully exposed, but there are scattered outcrops exhibit-
ing the beds and their dips.

The overthrust west of South Bethlehem is in the gentle flexures near the region
in which the Helderberg formations pitch up to the northward and extend to the
northwestward out of the flexed belt.

The characteristics of this overthrust are the fault in the hard, massive beds of
pentamerus limestone and an " underturned " flexure in the thin-bedded lower
limestone, involving the subjacent soft Hudson slates.

The overthrust is exposed only on Sprayt creek, which it crosses at an old mill
about three-quarters of a mile west-southwest of the village. Its trend is approxi-
mately north and south, but it does not appear to extend for any great distance.
The relations al the mill are illustrated in the accompanying figures, in which the
features above the broken-line portions of the sections are exposed in the bed and
banks of the creek. It is unfortunate that the exposures are not more complete,
but sufficient is in sight, I believe, to substantiate the interpretation I have given
in the figures. Only the upper surface of the crumple is exposed in the limestone,
but the greater part of the fault-plane is visible in the south bank of the creek

Figure 2. — Cross-section of Overthrust West of South Bethlehem, Albany County, New Fork.
Exposure on south bank of Sprayt creek, looking north (reversed).

above the dam. The overturned synclinal of slates and lowest limestone bed is
clearly exposed in the base of the high bank on the south side of the creek, where
the slate is seen to be excessively crumpled and its original bedding and cleavage
planes obliterated. In the north bank, under the mill, the exposure is less ex-
tensive, but, as is shown in figure 3, essentially similar relations exist.

The mechanism of this overthrust is, 1 believe, not di Hi cult to understand. 1
have represented the hypothesis of its development in the diagrams infigure'3:
I, the first stage ; II, the second, and the present conditions the third. The broken
line on I indicates the line of weakness, the arrow the direction of thrust. The
fault sheared diagonally through the hard, massive beds of pentamerus limestone,
hut the softer, thin-bedded, underlying limestones in moving forward with the
thrust were not fractured, but folded downward and backward into the soft shales

N. H. DARTON TWO OVERTHRUSTS IX NEW YORK.

|:;«.i

below, as shown by the arrows in IT. The fault truncated a small portion of a
preexistent arch of the lower limestones at J and carried them to II. The amount

Figure 'A.— Over thrust on Sprayt Creek. Section on north Bank, looking North.
i and II arc hypothetical sections to illustrate two stages in the development of the overthrust.

of displacement was about 100 feet. The principal force in the overthrust was
from the east, and almost horizontal in direction, unless the present law angles of
fault and axial planes are due to subsequent backward tilting.

The last paper was read by title :

A GEOLOGICAL RECONNOISSANCE IN THE CENTRAL TAUT OF THE STATE OF

WASHINGTON

BY ISRAEL C RUSSELL

The President announced the completion of the scientific program.
The following resolutions were offered by Mr Frank I). Adams and
unanimously adopted :

"Resolved, That the thanks of the Geological Society of America be tendered—
"To His Excellency the Governor-General of the Dominion of Canada fur the

cordial welcome which he extended to the Society, and to Her Excellency Lady

Stanley for her very kind hospitality ;

440

PROCEEDINGS OF OTTAWA MEETING.

"To the Logan Club for its invitation to the Society to meel in Ottawa and for
its generous hospitality, and especially to its committee, consisting of 1 >r A. 1!. ( !.
Selwyn, Dr R. W. Ells, Mr J. B. Tyrrell and Mr W. H. C. Smith, whose untiring
efforts have so largely contributed to the success of the meeting;

"To the Royal Society of Canada, and to its committee, consisting of Dr J. < '<.
* Bourinot and Mr James Fletcher, for their invitation to meet in Ottawa, and for
their kind attentions during the Society's visit ;

"To the Clerk of the House of Commons, Dr J. G. Bourinot, for the ample
suite of rooms which he lias placed at the disposal of the Society during this
meeting."

Remarks upon the resolutions were made by C. \l. Van Hise, H. L.
Fairchild, W J McGee, B. K. Emerson and G. K. Gilbert expressing the
genera] sentiment that the Fifth Annual Meeting had been surpassingly

successful and pleasant.

With a few appropriate remarks the President declared the meeting
closed.

Register of the Ottawa Meeting, 1892.
The following Fellows were in attendance upon the meeting

F. D. Adams.
H. M. Ami.

A. E. Barlow.
Robert Bell.

H. P. H. Brumell.
Robert Chalmers.
J. S. Diller.
R. W. Ells.

B. K. Emerson.
H. L. Fairchild.
E. R. Faribault.

G. K. Gilbert.
N. J. Giroux.
U. S. Grant.

J. V.

C. W. Hayes.
C. H. Hitchcock.
L. M. Lam be.
A. P. Low.
W J McGee.
W. McInnes.
R. D. Salisbury.
A. R. C. Selwyn.
T. W. Stanton.
J. B. Tyrrell.
Warren Upham.
C. R. Van Hise.
I. C. White.
G. F. Wright.
Whiteaves, Fellow-elect.

Total attendance. 29.

LIST OF

OFFICERS AND FELLOWS OF THE GEOLOGICAL SOCIETY

OF AMERICA.

OFFICERS FOR 1893.

Presidi nt.

Sib J. William Dawson, Montreal, Canada.

Vice-Presidents.

T. C. Ciiamberlin, Madison, Wis.
J. J. Stevenson, New York City.

Secretary.

II. L. Fairchild, Rochester, New York.

Treasurer.

I. C. White, Morgantown, W. Va.

Councillors.

Class of 1895.

E. A. Smith, University, Alabama.
C. D. Walcott, Washington, D. C.

( 'lass of 1894.

Henry S. Williams, Ithaca, New York.
X. II. Winchell, Ann Arbor, Mich.

Class of 1893.

George M. Dawson, Ottawa, Canada.
John C. Branner, Little Rock, Arkansas.

Editor.

.1. Stanley-Brown, Washington, I). C.

(441)

442 PROCEEDINGS OF OTTAWA MEETING.

FELLOWS, JULY 81, 1898.

-Indicates Original Fellow (see article III of Constitution).
t Indicates decedent.

Frank Dawson Adams, Montreal, Canada ; Lecturer on Geology at McGill College.
December, 1889.

Victor C. Alderson, 0721 Honore St., Englewood, 111. December, 1889.

Truman H. Aldrich, M. E., 92 Southern Ave., Cincinnati, Ohio. May, 1889.

Henry M. Amt, A. M. , Geological Survey Office, Ottawa, Canada; Assistant Paleon-
tologist on Geological and Natural History Survey of Canada. December, 1 889.

*t Charles A. Ashburner, M. S., C. E. (Died December 24, 1889.)

Alfred E. Barlow, B. A., M. A., Geological Survey Office, Ottawa, Canada;
Assistant Geologist on Canadian Geological Survey. August, 1892.

George H. Barton, B. S., Boston, Mass.; Instructor in Geology in Massachusetts
Institute of Technology. August, 1890.

William S. Baylev, Ph. D., Waterville, Maine; Professor of Geology in Colby
University. December, 1888.

* George F. Becker, Ph. D., Washington, D. C; U. S. Geological Survey.
Charles E. Beecher, Ph. D., Yale University, New Haven, Conn. May, 1889.
Robert Bell, C. E., M. D., LL. D., Ottawa, Canada; Assistant Director of the

Geological and Natural History Survey of Canada. May, 1889.

AlbertS. Bickmore, Ph. I)., American Museum of Natural History, 77th St. and
Eighth Ave., N. Y. city; Curator of Anthropology in the American Museum
of Natural History. December, 1889.

William P. Blake, New Haven, Conn. ; Mining Engineer. August, 1891.

Stephen Bowers, A. M., Ph. D., Mineralogical and Geological Survey of California,
Ventura, California. May, 1889.

Amos Bowman, Anacortes, Skagit Co., Wash. State. May, 1889.

Ezra Brainerd, LL. D., Middlebury, Vt; President of Middlebury College. De-
cember, 1889.

* John C. Branner, Ph. D., Menlo Park, Cal.; Professor of Geology in Leland

Stanford Jr. University ; State Geologist of Arkansas.

* Garland C. Broadiiead, Columbia, Mo.; Professor of Geology in the University

of Missouri.

* Walter A. Brownell, Ph. D., 905 University Ave., Syracuse, N. Y.

Henry P. H. Brltmell, Geological Survey Office, Ottawa, Canada; Assistant Geol-
ogist on Canadian Geological Survey. August, 1892.

* Samuel Calvin, Iowa City, Iowa; Professor of Geology and Zoology in the State

University of Iowa. State Geologist.
Henry Donald Campbell, Ph. D., Lexington, Va. ; Professor of Geology ami

Biology in Washington and Lee University. May, 1889.
Marius R. Campbell, U. S. Geological Survey. Washington, D. C. August, 1892.
Franklin R. Carpenter, Ph. D., Rapid City. South Dakota; Professor of Geology

in Dakota School of Mines. .May. L889.
Robert Chalmers, Geological Survey Office, Ottawa, Canada ; Field Geologist on

Geological and Natural History Survey of Canada. May. 1889.

LIST OF FELLOWS. 443

*T. C. Chamberlin, LL. D., Chicago, TIL; Head Professor of Geology, University

of Chicago.
Henry M. Chance, M. I)., Philadelphia, Pa.; Geologisl and Mining Engineer.

August, 1890.
*fJ. H. Chapin, Ph. I)., Meriden, Conn. (Died March 14, L892.)
Clarence Raymond Claghorn, B. S., M. E., 204 Walnut Place, Philadelphia, Pa.

August, 1891.
-William B. Clark, Ph. P., Baltimore, Md.; Instructor in Geology in Johns

Hopkins University.

* Edward W. Claypole, 1 >. Sc. , Akr< »n, < ). ; Profess* >r of ( i& >1< »gy in Buchtel College.
A \i;ox II. Cole, A. M., Englewood, 111. December, 1889.

* John Collett, A. M., Ph. !>.. Indianapolis, End.; lately State Geologist.
*Theodore B. Comstock, Tucson, Ariz.; President of the University of Arizona,
t George H. Cook, I'h. D., LL. D. (Died September 22, 1889.)

* Edward D. Cope, Ph. D., 2102 Pine St., Philadelphia, Pa.; Professor of Geology

in the University of Pennsylvania.

* Francis W. Cragin, B. S., Colorado Springs, Col.; Professor of Geology and

Natural History in ( iolorado College.
-" Albert R. Craxdall, A. M., Lexington, Ky.; Professor of Geology in Agri-
cultural and Mechanical College of Kentucky.

* William 0. Crosby, B. S., Boston Society of Natural History, Boston, Mass.;

Assistant Professor of Mineralogy and Lithology in Massachusetts Institute of
Technology.
Charles Whitman Cross, Ph. D., U. S. Geological Survey, Washington, D. C.
May, 1889.

* Malcolm H. Crump, Bowling Green, Ky.; Professor of Natural Science in Ogden

( !o Uege.
Garry E. Culver, A. M., Beloit, Wis. December, 1891.

* Henry P. Cushing, M. S., Cleveland. Ohio; Instructor in Geology, Adelbert Col-

lege.
T. Nelson Dale, Williamstown, Mass.; Assistant Geologist, U. S. Geological Sur-
vey. December, 1890.

* James D. Dana, LL. D., New Haven, Conn.; Professor of Geology in Yale Uni-

versity.

* Nelson H. Darton, United States Geological Survey, Washington, D. C.

^ William M. Davis, Cambridge, Mass.; Professor of Physical Geography in Har-
vard University.
George M. Dawson, D. Sc, A. R. S. M., Geological Survey Office, Ottawa, Canada ;

Assistant Director of Geological and Natural History Survey of Canada. May,

1889.
Sir J. William Dawson, LL. D., McGill College, Montreal, Canada: Principal of

McGill University. May, L889.
David T. Day, A. B., Ph. D., U. S. ( feological Survey, Washington, D. C. August .

1891 .
Antonio del Castillo, School of Engineers, City of Mexico; Director of National

School of Engineers; Director Geological Commission, Republic of Mexico.

August, 1892.
Frederick P. Dewey, Ph. P.., 621 F St. N. W., Washington, D. C. May. 1889

IA'V— r.n.i,. Geol. Soc. Am., Vol. I, 1892.

Ill PROCEEDINGS OF OTTAWA MEETING.

Orvili.e A. Derby, M.S., Sao Paulo, Brazil; Director of the Geographical and
Geological Survey of the Province of Sao Paulo, Brazil. December, 1890.

* Joseph S. Diller, B. S., United States Geological Survey, Washington, I). ('.
Edward V. d' I nvilliers, E. M., 711 Walnut St., Philadelphia, Pa. December,

1888.

* Edwin T. Dumble, Austin, Texas; State Geologist.

Clarence E. Dutton, Major, I . S. A., Ordnance Department. San Antonio, Texas.
August, 1891.
William B. Dwight, M. A.. Ph. B., Poughkeepsie, N. Y.; Professor of Natural
History in Vassar College.

-George H. ELDRiixiE, A. B., United States Geological Survey, Washington, 1>. ( '.

Robert W. Ells, LL. D., Geological Survey Office, Ottawa, Canada; Field Geolo-
gist on Geological and Natural History Survey of Canada. Decemher, 1888.

* Benjamin K. Emerson, Ph. D., Amherst, Mass.; Professor in Amherst College.

* Samuel F. Emmons, A. M., E. M., U. S. Geological Survey. Washington, D. C.
John Eyerman, Easton, Pa. August, 1891.

Harold W. Fairbanks, B. S., Berkeley, Cal.; Geologist State Mining Bureau.
August, 1892.

* Herman L. Fairciiild, B. S., Rochester, N. Y.; Professor of Geology and Natural

History in University of Rochester.
J. C. Fales, Danville, Kentucky; Professor in Centre College. December, 1888.
Eugene Rudolph Faribault, C. E., Geological Survey Office, Ottawa. Canada.

August, 1891.
P. J. Farnswortii, M. D., Clinton, Iowa ; Professor in the State University of Iowa.

May, 1889.
Moritz Fischer, 721 Cambridge St., Cambridge, Mass. May, 1889.

* Albert E. Foote, M. I)., 4116 Elm Ave., Philadelphia, Pa.

William M. Fontaine, A. M., University of Virginia, Va.; Professor of Natural
History and Geology in University of Virginia. December, 1888.

*P. Max Fosiiay, M. S., M. D., 282 Prospect St., Cleveland, Ohio.

*Persipor Frazer, D. Sc, 1042 Drexel Building, Philadelphia, Pa.; Professor of
Chemistry in Franklin Institute.

* Homer T. Fuller, Ph. D., Worcester, Mass.; Professor of Geology in Worcester

Polytechnic Institute.
Henry Gannett, S. B., A. Met. B., U. S. Geological Survey, Washington, D. C.
December, 1891.

* Grove K. Gilbert, A. M., United States Geological Survey, Washington, D. C.
Adams C. Gill, A. B., Northampton, Mass. Decemher, 1888.

N. J. Giroux, C. E., Geological Survey Office, Ottawa, Canada; Assistant Field
Geologist, Geological and Natural History Survey of Canada. May. 1889.

Ulysses Sherman Grant, Ph. D., University of Minnesota, Minneapolis, Minn.;
Assistant on Geological Survey of Minnesota. Decemher, 1890.

* George B. Grinnell, Ph. D., 318 Broadway, New York city.

Leon S. Griswold, A. B., 238 Boston St., Dorchester, Mass. August. L892.

* William F. E. Gurley, Sptingfield, 111.; State Geologist.

Arnold Hague, Ph. B., U. S. Geological Survey, Washington, D. C. May, 1889.

* Christopher W. Hall, A.M., 803 University Ave.. Minneapolis. Minn.; Pro-

fessor of Geology and Mineralogy in University of Minnesota.

LIST OF FELLOWS. 44o

.1 imks II \u., LL. I)., State Hall, Albany, N. Y.; State Geologist and Director of
the State Museum.

Henry G. Hanks, 1124 Greenwich St., San Francisco, Cal.; lately State Mineralo-
gist. December, 1888.

John B. Hastings, M. E., Boise City, Idaho. May, 1889.

* Erasmus Haworth, Ph. D., Oskaloosa, Iowa; Professor of Natural Sciences in

Penn College.
■ Robert Hay, Box 5G2, Junction City, Kansas ; Geologist, U. S. Department of

Agriculture.
C. Willard Hayes, Ph. D., U. S. Geological Survey, Washington, D. C. May,

1889.
Angelo Heilprin, Academy of Natural Sciences, Philadelphia, Pa.; Professor of

Paleontology in the Academy of Natural Sciences.
Clarence L. Herrick, M. S., 324 Hamilton Ave., North Side, Cincinnati, Ohio;

Professor of Geology and Biology in the University of Cincinnati. May, 1889.

* Lewis E. Hicks, Lincoln, Nebraska.

* Eugene W. Hilgard, Ph.D., LL. D., Berkeley, Cal.; Professor of Agriculture in

University of California.
Frank A. Hill, 208 S. Centre St., Pottsville, Pa.; Geologist in Charge of Anthra-
cite District, Second Geological Survey of Pennsylvania. May, 1S89.

* Robert T. Hill, B. S., U. S. Geological Survey, Washington, D. C.
*Charles II. Hitchcock, Ph. D., Hanover, N. H.; Professor of Geology in Dart-
mouth College.

William Herbert Hobbs, B. Sc, Ph. D., Madison. Wis.; Assistant Professor of

Mineralogy in the University of Wisconsin. August, 1891.
*Levi Holbrook, A. M., P. 0. Box 536, New York city.

* Joseph A. Holmes, Chapel Hill, North Carolina ; State Geologist and Professor of

Geology in University of North Carolina.
Mary E. Holmes, Ph. D., 201 S. First St., Rockford, Illinois. May, 1889.
t David Honeyman, D. C. L. (Died October 17, 1889.)

* Jedediah Hotchkiss, 346 E. Beverly St., Staunton, Virginia.

* Edmund O. Hovey, Ph. D., Jefferson City, Mo.

* Horace C. Hovey, D. D., Bridgeport, Conn.

-Edwin E. Howell, A. M., 537 15th St. N. W., Washington, D. C.

t Thomas Sterry Hunt, D. Sc, LL. D., Park Avenue Hotel, New York city. De-
cember, 1889. (Died February, 1892.)

*Alpheus Hyatt, B. S., Boat. Soc. of Nat. Hist., Boston, Mass.; Curator of Boston
Society of Natural History.

Joseph P. Iddings, Ph. B., Professor of Petrographic Geology, University of Chi-
cago, Chicago, 111. May, 1889.

A. Wendell Jackson, Ph. B., Berkeley, Cal.; Professor of Mineralogy, Petrog-
raphy and Economic Geology in University of California. December, 1888!

Thomas M. Jackson, C. E., Morgantown, W. Va.; Professor of Civil and Mining
Engineering in West Virginia University. May, 1889.

* Joseph F. James, M. S., Department of Agriculture, Washington, D. C.
Walter Proctor Jenney, E. M., Ph. D., United States Geological Survey, Wash-
ington, D. C. August, L891.

* Lawrence C. Johnson, United States Geological Survey, Meridian, Miss.

44() PROCEEDINGS OE OTTAWA MEETING.

::" Willard D. Johnson, United States Geological Survey, Berkeley, Cal.
Alexis A. Julien, Ph. I)., Columbia College, New York city: Instructor in Co-
lumbia College. May, 1889.
Edmund Jussen, Ph. D., Temple, Carroll Co., Ga. December, L890.
Arthur Keith, A. M., U. S. Geological Survey, Washington, D. ( '. May. L889.

* James F. Kemp, A. B., E. M., Columbia College, New York city; Adjunct Pro-

fessor of Geology.
Charles Rollin Keyes, A. M., Ph. D., Assistant State Geologist, Des Moines, Iowa.

August, 1890.
James P. Kimball, Ph. D., Washington, P. C. August, 1891.
Clarence King, IS Wall St., New York city ; lately Director of the I". S. ( ieolog-

ical Survey. May, 1889.
Frank H. Knowlton, M. S., Washington, D. C; Assistant Paleontologist I'. S.

Geological Survey. May, 1889.

* George F. Kunz, 402 Garden St., Hoboken, N. J.
Ralph D. Lacoe, Pittston, Pa, December, 1889.

George Edgar Ladd, A. B., A. M., 81 Oxford St., Cambridge, Mass. August,
1891.

J. C. K. Laflamme, M. A., D. D., Quebec, Canada: Professor of Mineralogy and
Geology in University Laval, Quebec. August, 1890.

Lawrence M. Lambe, Ottawa, Canada; Artist and Assistant in Paleontology and
Geological Survey of Canada. August, 1890.

Alfred C. Lane, Ph. D., Houghton, Mich.; Assistant on Geological Survey of
Michigan. December, 1889.

Daniel W. Langdon, Jr., A. B., University Club, Cincinnati, Ohio; Geologist of
Chesapeake and Ohio Railroad Company. December, 1889.

Andrew C. Lawson, Ph. P., Berkeley, Cal.; Assistant Professor of Geology in tin-
University of California. May, 1889.

* Joseph Le Conte, M. D., LL. D., Berkeley, Cal.; Professor of Geology in the

University of California.

*J. Peter Lesley, LL. D., 100S Clinton St., Philadelphia, Pa.; State Geologist.

Frank Leverett, B. S., 4103 Grand Boulevard, Chicago, 111.; Assistant U. S. Geo-
logical Survey. August, 1890.

Josua Lindahl, Ph. D., Springfield, 111.; State Geologist, August, 1890.

Waldemar Lindgren, U. S. Geological Survey, Washington, 1). C. August,
1890.

Robert H. Loughridge, Ph. D., Berkeley, Cal.; Assistant Professor of Agricultural
Chemistry in University of California. May, L889.

Albert P. Low, B. S., Geological Survey Office, Ottawa, Canada : Assistant Geolo-
gist on Canadian Geological Survey. August, 1892.

Thomas H. McBride, Iowa City. Iowa; Professor of Botany in the State University
of Iowa. May, 18S9.

Henry McCalley, A. M., C. E., University, Tuscaloosa County, Ala.; Assistant on
Geological Survey of A la ha ma. May. L889.

Richard G. McConnell, A. 1!., Geological Survey Office, Ottawa, Canada ; I "icdd
Geologist on Geological and Natural History Survey of Canada. May, 1889.

James Rieman Macpaklane, A. IS., Pittsburg, Pa. August, L891.

*WJ.McGee, Washington. I >. ('.; Bureau of North American Ethnology.

LIST OF FELLOWS. 1 17

William McInnes, A. B., Geological Survey Office, Ottawa, Canada; Assistant

Field Geologist, Geological and Natural History Survey of ( !ana< la. May, 1889-
Peter McKellak, Fort William, Canada. August, 1890.
Oliver Marcy, LL. D., Evanston, Cook Co., 111.; Professor of Natural History in

Northwestern University. May, 1889.
Othniel C. Marsh, Ph. D., LL. D., New Haven, Conn.; Professor of Paleontology

in Yale University. May, 1S89.
Vernon F. Marsters, A. B., Bloomington, Ind.; Associate Professor of Geology in

Indiana State University. August, L892.
1'. H. Mell, M. E., Ph. D., Auburn, Ala.: Professor of Geology and Natural History

in the State Polytechnic Institute. December, 1888.

* Frederick J. H. Merrill, Ph. !>., State Museum, Albany, N. Y.; Assistant State

Geologist and Assistant Director of State Museum.
George P. Merrill, M. S., U S. National Museum, Washington, D. G; Curator

of Department of Lithology and Physical Geology. December, 1888.
James E. Mills, B. S., Quincy, Plumas Co., Cal. December, 1888.

* Albro D. Morrill, A. M., M. S., Clinton, N. Y.; Professor of Geology in Hamilton

College.
Thomas F. Moses, M. I). , Urb.ina, < >hio ; President of Urbana University. May, 1889.

* Frank L. Nason, A. B., 5 Union St., New Brunswick, N. J.; Assistant on Geo-

logical Survey of New Jersey.

* Henry B. Nason, Ph. I)., M. D., LL. D., Troy, N. Y.; Professor of Chemistry and

Natural Science in Rensselaer Polytechnic Institute.

* Peter Neep, A. M., 361 Russell Ave., Cleveland, Ohio.

*t John S. Newberry, M. D., LL. D. (Died December 7, 1892.)

Frederick H. Newell, B. S., U. S. Geological Survey, Washington, D. C. May,

1889.
William II. Niles, Ph. B., M. A., Cambridge, Mass. August, 1891.

* Edward Orton, Ph. D., LL. D., Columbus, Ohio; State Geologist and Professor

of Geology in the State University.
:; \\ios 0. Osborn, Waterville, Oneida Co., N. Y.
*t Richard Owen, LL. 1). (Died March 24, 1890.)

* Horace B. Patton, Ph. D., Golden, Col.; Professor of Geology and Mineralogy

in Colorado School of Mines.
Richard A. F. Penrose, Jr., Ph. I)., 1331 Spruce St., Philadelphia, Pa. May,

1889.
Joseph H. Perry, 176 Highland St., Worcester, Mass. December, 1888.

* William H. Pettee, A. M., Ann Arbor, Mich.; Professor of Mineralogy, Eco-

nomical Geology, and Mining Engineering in Michigan University.

* Fbanklin Platt, 1319 Walnut St., Philadelphia, Pa.

* Julius Pohlman, M. I)., University of Buffalo, Buffalo, N. V.

William B. Potter, A. M., E. M., St. Louis, Mo.; Professor of Mining and Metal-
lurgy in Washington University. August, 1890.
*Joiin W. Powell, Director of U. S. Geological Survey. Washington, l». 0.
*John It. Procter, Frankfort, Ky.; State Geologist.

* Charles S. Prosser, M. S., Topeka, Kan.; Professor of Geology in Washington

College.

* Raphael Pumi'elly, U S. Geological Survey, Newport, R. I.

448 PROCEELINGS OF OTTAWA MEETING.

Harry Fielding Reid, Ph. D., Johns Hopkins University, Baltimore, Md. De-
cember, L892.

William North Rice, A. M., Ph. D., LL. D., Middleton, Conn.; Professor of
Geology in Wesleyan University. August, 1890.

* Eugene N. S. Ringueberg, M. I'.. Lockpori, X. V.

Charles W. Rolfe, M S., Urbana, Champaign Co.. 111.; Professor of Geology in
University of Illinois. May, 1889.

* Israel C. Russell, M. S., Ann Arbor, Mich.; Professor of Geology in University

of Michigan.

* James M. Sapford, M. D., LL. D., Nashville, Tenn.; State Geologist; Professor

in Vanderbilt University.

Orestes II. St. John, Topeka, Kan. May, 1889.

*Eollin D. Salisbury, A. M., Chicago, 111.; Professor of General and Geographic
< ieology in University of Chicago.

Frederick W. Sardeson, University of Minnesota, Minneapolis, Minn. Decem-
ber, 1892.

* Charles Schaeffer, M. D., 1309 Arch St., Philadelphia, Pa.

William B. Scott, M. A., Ph. D., Princeton, N. J.; Professor, Collegeof New .Jer-
sey. August. 1892.

Henry M. Seely, M. D., Middlebury, Vt.; Professor of Geology in Middlebury
College. May, 1889.

Alfred R. C. Sklwyx, C. M. G., LL. 1)., Ottawa. Canada ; Director of Geological
and Natural History Survey of Canada. December, 1889.

* NatiiaxielS. Shaler, LL. D., Cambridge, Mass.; Professor of Geology in Har-
vard University.

Will H. Sherzer, M. S., Ypsilanti, Mich.; Professor in State Normal School.
December, 1800.

* Frederick W. Simonds, Ph. D., Austin, Texas; Professor of Geology in Univer-

sity of Texas. 4 '

* Eugene A. Smith, Ph. D., University, Tuscaloosa Co., Ala.; State Geologist and

Professor of Chemistry and Geology in University of Alabama.

*John C. Smock, Ph. D.. Trenton, N. J.; State Geologist.

Charles II. Smyth, Jr., Ph. D., Clinton, N. Y.: Professor of Geology in Hamilton
College. August, L892.

*J. W. Spencer, A. M., Ph. D., Atlanta, Georgia; State Geologist.

Joseph Stanley-Brown, Assistant Geologist U. S. Geological Survey, Washington,
D. C. August, is'. ii'.

Timothy William Stanton, B. S., U. S. Geological Survey, Washington. D. C. ;
Assistant Paleontologist I . S. Geological Survey. August. 1891.

*John .1. Stevenson, Ph. D.,-LL. D., University of the City of New York; Pro-
fessor of Geology in the University of the City of New York.

George C. Swallow, M. D., LL. D., Helena, Montana; State Geologist; lately
State Geologist of Missouri, and also of Kansas. December, 1889.

Ralph S. Tarr, Cornell University. Ithaca, X. Y. August. 1890.

Maurice Thompson, Crawfordsville, Ind.; lately State Geologist. May. 1889.

*As\ Scott Tiffany, 901 West Fifth St.. Davenport, Iowa.

* James E. Todd, A. M, Vermillion, s. Dak.: Professor of Geology and Mineralogj

in University of South Dakota.

LIST OF FELLOWS. 449

* Henry W. Turner, U. S. Geological Survey, Washington, D. C.

Joseph B.Tyrrell, M. A., B. Sc, Geological Survey Office, Ottawa, Canada;
Geologist on the Canadian Geological Survey. May, 1889.
Edward O. Ulrich, A. M., Newport, Ky.; Paleontologist of the Geological Sur-
vey of Minnesota.

* Warren Upham, A. B., Assistant Geological Survey of Minnesota; Minneapolis,

Minn.

* Charles R. Van Hise, M. S., Madison, Wis.; Professor of Mineralogy and Pe-

trography in Wisconsin University ; Geologist II. S. Geological Survey.

* Anthony W. Vogdes, Alcatraz Island, San Francisco, Cal.; Captain Fifth Artil-

lery, IT. S. Army.
Charles Wachsmuth, M. D., Burlington, Iowa. May, 1889.
*Marshman E. Wadsworth, Ph. E>., Houghton, Mich.; State Geologist ; Director

of Michigan Mining School.

* Charles D. Walcott, U. S. National Museum, Washington, D. C; Paleontolo-

gist U. S. Geological Survey.

Lester F. Ward, A. M., U. S. Geological Survey, Washington, D. G; Paleontolo-
gist U. S. Geological Survey. May, 1889.

Walter H. Weed, M. E., TJ. S. Geological Survey, Washington, D. C. May,
1 889.

David White, U. S. National Museum, Washington, D. C; Assistant Paleontolo-
gist U. S. Geological Survey, Washington, D. C. May, 1889.

* Israel C. White, Ph. D., Morgantown, W. Ya. ; Professor of Geology in West

Virginia University.

* Charles A. White, M. D., U. S. National Museum, Washington, D. C; Paleon-

tologist U. S. Geological Survey.
Joseph Frederic Whiteaves, ( >ttawa, Canada; Paleontologist and Assistant Di-
rector Geological Survey of Canada. December, 1892.

* Robert P. Whitfield, Ph. D., American Museum of Natural History, 77th St-

and Eighth Ave., New York city ; Curator of Geology and Paleontology.
Charles L. Whittle, West Medford, Mass.; Assistant Geologist U. S. Geological
Survey. August, 1892.

* Edward H. Williams, Jr., A. C, E. M., 117 Church St., Bethlehem, Pa.; Pro-

fessor of Mining Engineering and Geology in Lehigh University.

* George H. Williams, Ph. D., Johns Hopkins University, Baltimore, Md.; Pro-

fessor of Inorganic Geology in Johns Hopkins University.

* Henry S. Williams, Ph. D., New Haven, Conn.; Professor of Geology and Paleon-

tology in Yale University.

* t J- Francis Williams, Ph. D., Salem, N. Y. (Died November 9, 1891. )

* Samuel G. Williams, Ph. D., Ithaca, N. Y.; Professor in Cornell University.
Bailey Willis, U. S. Geological Survey, Washington, D. C. December, 1889.

■ I Alexander Winchell, LL. D. (Died February 19, 1891.)

* Horace Vaughn Winchell, 1306 S. E. 7th St., Minneapolis, Minn.; Assistant

on Geological Survey of Minnesota.

* Newton H. Wincuell, A. M., Minneapolis, Minn.; State Geologist ; Professor in

University of Minnesota.
; Arthur Winslow, B. S., Jefferson City, Mo.; State Geologist.
John E. Wolff, Ph. I)., Harvard University, Cambridge, Mass.; Instructor in
Petrography, Harvard University. December, 1889.

450 PROCEEDINGS OF OTTAWA MEETING.

Robert Simpson Woodward, C E., Columbia College, New York city; Professor

of Mechanics in Columbia College. May, 1889.
*G. Frederick Weight, D. I)., Oberlin, Ohio ; Professor in Oberlin Theological

Semi miry.
Lorenzo G. Yates, M. D., Santa Barbara, Cal. December, L889.

Summary.

< ►riginal Fellows 109

Elected Fellows 124

Aggregate 233

Deceased Fellows (.i

Membership July 3] , 1893 224

INDEX TO VOLUME 4.

432,

Abbott, C. C, cited on glacial man

Acan rHODiCTYA, New species of

Adams, F. D., appointed a teller

— cited on anorthosite masses

epidote

— , Record of discussion by 40!)

— , Resolution of thanks offered by

Agassiz, Louts, cited on Bethlehem glacier. .
glacial phenomena in the White

mountains

— , Glacial studies of

Age of the earth, W. Upham's estimate of

the

Alaska, Geology of Middleton island

A 11:1: iNT, , Acknowledgments to

Alpine glacial phenomena referred to

Ami, II. M , Discussion by

— , Record of discussion by

— , Titles of papers by..

Ammonoosuc liver, Glacier of the

Analysis of epidote

Ancient waterways; A. s. Tiffany

Andrews, E. B., cited on Paleozoic plants

Antartic ice-sheet

Archean of Canada, Economic geology of

the ' ; ;;i:,

New York, Thickness of

— (The) rocks west of Lake Superior; \V.

II- V. Smith

Artesian well borings furnish evidence of

ancient waterways

Asina i:\f.k, ('. A., cited on Fulton well

the Lorraine shale

— , Eastern New York scot prepared

by 116, 117,

Auditing Committee, Report of

Bailey, L. W.. cited on the Laurentian

Baldwin, C. C, Collection of glacial material
by

ige

L'Ot

409
378
35 I

::in

AM

139

4

191

204
127
107
5,7
4i IS
410
411)
4
308
lo
124
L9.2

,'lls
lis

Baldwin, D. C, Collection of glacial materia
1;

by.

wii.ow, A. E., Announcement ol election
of.

11
Kit;
114

lis
132

300
423
423

372
;:;.i
338
342
1
434

— cited on the Laurentian

— and Huronian rocks

Coutchiehing

— , Flection of.

— , Record of discussion by

— ; Relations of the Laurentian and Huronian

rocks north of Lake Huron 313

— , Title of paper by 133

I', utitois, < '., cited on granites of Rost renen.. ;;o|

l'.\i;i 1 \, (_'., cited oil Paleozoic plants L25

l; \ I OF f'l ND1 coast ill the glacial period 301

Beaumont, Eliede, cited 'igin of granite. 307

Lie ma:, !•'.., cited on epidote 310

Becker, G. F., cited on distribution of the

Knoxville beds : 213

early Cretaceous of California and

Oregon 249

gold belt 258

Oregon fossils 212

relation of Mariposa beds 22:;

the Tejon formation J 17

Tertiary 201, 297

— unconformity between Chico and

Shasta groups 'Jus

Page
Becker, G. F. ; Finite homogeneous -train,

How and rupture of rocks 13

— , Reference to present survey of the gold

belt by 222

— , Title of paper by ii

Bell, Robert, Appointed an au.iitor r;~s

— cited on the Laurentian 351

— . Discussion by 425

— , Quoted on rocks near Killarn.-y village.. 310

— , Record of discussion by '. 411, 122

—, Reference to "The pet rolouiu field Ol

Ontario " by 22(5

— , Title of paper by 432

Berkshire schists, Metamorphism of the 167

Bibliography of J. II. Chapin 408

J. h. Newberry : 399

T. Sterry Hunt 385

Blomstrand, C. W., cited on allauite 307

epidote 310

Blytt, A., cited on interchange of land and

water 17; I

Boston Society of Natural History, Invita-
tion from 432

Bourinot, J. G., Acknowledgments to 140

Branner, .1. ('., Reading ol paper by 7

Bringieh, Louis, cited on earthquake 11 1

British Columbia, Glacial phenomena in 7

Broadhead, G. < '., Title of paper by 7

Brooks, T D , cited on the Potsdam lis

Browne, R. E , cited on Neocene chan-
nels 261, 266, 281, 290, 291, 295

— , Elevations taken fr surveys by SJ63

Brown, W. <.,»., cited on Oregon fossils 212

unconformable fossiliferous strata

in California 217

— , Collections from the lax cue of Oregon

by 219

— , Fossil collections made in California by. 20s

Brumell, H P. II., Election of 1,372

— ; Notes on the occurrence of petroleum
in Gaspe, Quebec .'. 241

— ; On the geology of natural gas and petro-

leum in southwestern Ontario 225

— , Titles of papers by 408, 4u:i

Bryant, H. G.. Donation of photographs by.. 117

Bulletin, Cost of 37G

— , Distribution of 373

California, Cretai is and Tertiary of

northern 205

— , Eocene of 217

— , Fossils of 209, 210, 250, 251, 252

, List of localities of 2.;;

— , N sene rivers of 257

— , Pleistocene of 297

— , Shasta and Chico formations in 245

Calvin, Sami el, Record ol discussion by 11

Cambro-Siluuian sections in Ontario 227

Campbell, M. 1.'., Election of 2, 372

— , Title of paper by id

Canada, Archean rocks of 333

— , Fossil sponges from Lower Cambro Silu-
rian of

— , Gas and petroleum ii 'io 225, lev

- , Geologic sections in 227. 2:; 1

— , Glacial geology ol western Labrador and
northern Quel H9

— , Laurent ia 11 of t he ( 11 taw a district :; la

LXVI— Bull. Geol. See. Am.. Vol. I, L892,

(451)

452

BULL. GEOL. SOC. AM.

Page
Canada, Relations of Laurentian and Huro-

nian rocks in 318

Carboniferous, Fossils of the 119

i \-i ii i ". A. del. Election of 2, 372

Catskill group, Oneonta sandstone's rela-
tion to 8

Chalmers, Robert, cited on glacial on 368

Pleistocene subsidence 367

— ; Height of tin- Ray of Fundy coast in
the glacial period relative to sea-level,
a- evidenced by marine fossils in the
bowlder-clay at Saint John, Now Bruns-
wick '. 361

— . Title "!' paper by 422

Chamberlin, T. i .. cited on drift 200

interglacial epoch 203

— , Election of, as First Vice-President 378

i ii ipin, .1. H.. Announcement of death of :7l'

— . Memorial and bibliography of W6

Chapman, E. J., cited on terraces i-~

Chemung group, Oneonta sandstone's rela-
tion to 8

i ,„, ,, beds of fossils 207

— formation 245

, Correlation of the '-'"'4

Chlorite schists 104

Clatpole, E. W., Discussion by in, 11

on the Connecticut valley glacier by... T

Oneonta sandstone by 8

— , Record of discussion by 2

— , Title of paper by 3

Cleavage, Theory of slaty, 66

Comparison of Pleistocene and present ice-
sheets: w. Upham lid

Comox coal-field, Age of l'4s

Conditions of accumulation of drumlins;

Warren Upham 9

Condon, r., .AttceMa-bearing rock in collec-
tions of _'1T

— cited on the Tertiary of Oregon 219

— , Collection of California Jurassic fossils

made by 221

Conglomerate, Dynamic and metosomatic

phenomena in a metamorphie 147

Conrad, T. A., cited on age of the Tejon for-
mation 247

Correlation of the Pacific coast forma-
tions 253, 254

Continental problems; G. K.Gilbert 179

Connecticut, Metamorphism of the sehi-ts

of 167

— (Studies of the) valley glacier; C. H.

Hitchcock 3

< oi wil, Report of the 372

Cretai eous and early Tertiary of Northern

California and Oregon ; J. S. Diller 205

— beds of the Rocky mountains, Relation of

Pacific coast fauna to 254

— , Chico formation referred by Newberry to

the 245, 246

— , Fossils of the 209, 210, 250, 251, 252, 255

— of California correlated with Upper or

White chalk of Europe and Fort Pierre
ami Fox Hills groups of the upper Mis-
souri..: 246, 247. -1 Is

the Pacific coast region, Various views

on the 245

Vancouver and Queen Charlotte isl

and- 248, 253

i i:"ii. .1.. Theory of, referred to 202

Cross, Whitman, cited on allanite.... 306,307,311
Crysi ui'»,i;ii'in of epidote 308, 309

< i shin.;, II. P., cited on Muir glacier 196, 197

Dale, T. N., cited on feldspar 165

Xew England rocks 384

Dall, W. FL, cited on Middleton island., i-s. i.:n,

I :l
paleontology of California 207

relation of U'allala beds to the Chico.. 223

Page

Dall.W. EI., cited on Tertiary of Oregon 219

Dana, J. D , cited on drill....' 199

formation of mountains |s;;. 187

glacial phenomena in < onnecticut... 3

geology of Massachusetts n.7

ice-sheet 198

Oswego sandstone and Oneida con-
glomerate 114

— Pleist ic subsidence 367

preglacial uplifting 204

the Clinton 113

Hamilton Ill

Marcellus ! 1 1

Taeonic 38 1

Upper Helderberg 112

Utica shale 11. ">

Darton, X. H.: tin two overthrusts in e

ern New York 436

— , Title of paper by 4_'7

Darwin, G. H., cited on strength of earth

crust 179

Daubree, A., cited on experiment in crush-
ing 74. 75

— origin of granite 307

Davis, W. M., cited on areas of flexures 437

— , Election of, on Photograph Committee.... 415

— ; Memorial of. lames Henry Chapin 4(Mi

Dawson, <;. M., cited on AuceMa-bearing

rocks on the Skagit river 217

Cretaceous of Vancouver and Queen

Charlotte islands 248. 253

ice-sheet 198

Pleistocene subsidence 367

resemblance of rotten diorite to mi-
caceous sandstone 215

— Shasta-Chico series 218

— ; Notes on the geology of Middleton isl-
and, Alaska 427

Dawson, Sir J. W. ; Acknowledgment of
election as President 13 I

— cited on bowlder-clay fossils

Paleozoic plants Vi- I I

Pleistocene subsidence 367

— the Leda clay fauna 369

— , Election of, as President : 378

— ; Note on fossil sponges from the Quebec

group (Lower Cambro-Silurian) at Little
Metis, Canada 409

Deerfield river valley, Glacial phenomena
in the 3

Deformation and its resulting phenomena... 12

— , .Mathematics of 17

Devonian of Quebec anoil-bearing formation 'Jii

— rocks of central New York, Thickness of.. 91

— section- in Ontario 227

Diller, J. S., cited on fossils from California

and Oregon 24!

geology of California and Oregon..249, 256

Sierra Nevada 260

Wallala formation 253

— ; Cretac is and early Tertiary of north-
ern California and oregnii 205

— , Election of, on Photograph Committee.... 415

— . Reading of paper by 134

report by 415

— , Reference to collection oi fossils by '249

— , Title of paper by 435

Displai on nts, Mathematics of 17

Douglass, J., cited as biographer of T. S.

Hunt

DOUGLAS, M. E.. Survey- in California by... 262
1 mm .ii in-. Condition of accumulation of .... 9
Dunnington, A. F., Surveys in California bj
Dynamic (Some) and metasomatic phenom-
ena in a metamorphie conglomerate in
the Green mountains: C. I.. Whittle 117

Earthquake, A fossil ill

Economk geology of the Archean of Canada,

347, 348

INDEX TO Vol.. 4.

453

Page

K.du \KDs,<.. A., Acknowledgments to 105

Election of Fellows 1, 378

Officers for 1893 378

Elements (Some) of land sculpture; L. E.

Hicks 133

Elie de Beaumont cited on" origin of granite... 307
Ells, K. W., Acknowledgments tu 44u

— appointed a teller 378

— cited on Devonian sandstones of Que-

bec 241, 242

— , Reading of paper by 427

— ; The Laurentian of the Ottawa district.... 349

— , Titles of papers by 432, f;i

Emerson, B. K , Record of discussions by,

411. 433, 4:U

■ — remarks by 440

Emmons, E., cited on the Caleiferous 118

Clinton 113

Hamilton Ill

Lorraine shale 114

■ — Lower Helderberg 112

Lower Taconic 382, 384

Marcellus Ill

Niagara 113

Onondaga salt group Ill'

Oriskany 112

Oswego sandstone and Oneida eon-
glomerate 113

the Potsdam 118

Trenton 115

Tally limestone Ill

Upper Helderberg 112

Utiea shale 114

Emmons, S. P., cited on orographic move-
in cuts 222

Englehardt, F. E., cited on the Medina 113

wells and sections 102-105

Eocene of California 247

— , Chico formation referred by Trask to

the 245

Epidote as a primary component of eruptive

rocks; C. R. Keyes 305

Eruptive rocks, Epidote as a primary com-
ponent of 305

Ettingshausen, C. vex, cited on Paleozoic

plants 122

Fairbanks, H. W., Announcement of elec-
tion of. 372

— cited on distribution of the Knoxville

beds 213

relation of Mariposa beds 22:;

— , Discovery of new fossil localities by 220

— , Election of. 2

Fairchild, H. L., Election of, as Secretary... 378
— ; Proceedings of the Fourth Summer
Meeting, held at Rochester, August 15

and Id, 1892 1

— ; Proceedings of the Fifth Annual Meet-
ing, held at Ottawa, Canada, December

28, 20, and 30, 1892 :17I

. Reading oT memorial by 393

— , Record of remarks by 440

— , Reference to memorial of J. S. Newberry

by I1"!

Faunas (The) of the Shasta, and ('hie,, for-
mation ; T. W. Stanton 245

Feldspar, Secondary enlargement of 171

Fellows, Election of 1, 378

— , List of. 112

Ferkier, \V. F., cited on diabase 328

— , Microscopic examination of sand by 129

— quoted on microscopic el enact eristics of

contact rock 325

gneiss 324, 326, 131

quartzite 324, 325

Finite homogeneous strain. How aid rup-
ture of rocks; G. F. Becker 13

Fleming, S., cited on terraces 127

Fletcher, James, Acknowledgments to llu

Pagi

Flint, T., cited on earthquake ill

Flow of rocks 13

Foerste, A. V., cited on Lower Cambrian

fossils 1 18

New England rocks

Fontaine. W. M., cited on Paleozoic plants.. 121,

122, 126, 12s

Forbes, J. D., Glacial studies of. 191, las

Fossil (A) earthquake; W J McGee II I

Kessit. s. Carboniferous 119

— , Cretai us 250, 251, 255

— , Devonian '•!

— , Effect of strain upon 83

— from Middleton island 430

— , .Missouri 1 1

— of California 209, 210

, List of localities of 2:.:;

the glacial period in New Brunswick... 361

— .Silurian 91

Fossn, sponges (Note on) from tic Quebec
group (Lower Cambro-Silurian) at Little

Metis, Canada; .1. \V. Dawson 109

Fossils, Tertiary 250-252

Francis, G. E., Acknowledgments to 104

Fritsch, A. von, cited on allanite 307

GrABB, W. M., cited on California fossils 211

— — — Cretaceous beds of the Pacific

coast uI'.-l;.,!. -:,:;

Gannett, H. G., cited on altitudes 92

Gaspjs, Petroleum in 211

Garneau, , cited on the name Lauren-
tian 352

Gas-bearing horizons oi Ontario 236, 238

Gas (Natural) and petroleum in southwest-
ern Ontario 225, 108

Gas-wells of central New York 91

— , Daily output of some of the Ontario... 237-240
Geer, Gerard he, cited on Yoldia arctica.. 370, 122

Geikie, James, cited on drift 199

glacial epochs 203

man 204

relation of land and sen 1 ,a

Geikie, Sir A., cited on conglomerates :;ll

epidote 310

preglacial uplifting 204

schistosity 75

term "Arehean " eel

— quoted on terrestrial readjustments 3 1 1

— , Reference to J. S. Newberry by 398

Genera of fossils, New 119, HO

"Geology of Vermont" cited on glaciation... 4

— (On the) of natural gas and petroleum in

southwestern 1 Intario; II. P. 11. Brumell. 225
Gilbert, G. K., Cited on glacial hypothe-
sis 123-425

jointing 72

land sculpture 136, 138, 140, 112

the Tertiary 259

— ; Continental problems 17!i

— , Discussion on 1 ineonta sandstone by

the Connecticut valley glacier by.... 7

— , First geologic work of 396

— , Introductory remarks by President 1

— , Meeting called to order by 372

— , Record of discussion by 41 1

remarks by 1 10

— , Title of presidential address by I

Glacial geology of western Labrador and
northern Quebec

— man

- period, Fossils of the

- in New Brunswick

- 1 Post) outlet of the 1 treat lakes

lacier. Bethlehem

. of the Ammonoosuc over

Connecticut valley

1 \. 11 i:s. Pleistocene and present

(oeppert, II. L-. cited on Pali ints

12;,

11:1
204

361

I
1

191

122,
125

L54

BULL. GEOL. SOC. A.M.

Page
Goodyear, W. A., cited on auriferous gravels,

259, 261

Neocene channels 284-286

— , Elevations taken from observations of 263

Gosselet, J., cited on ottrelite l T<">, 177

Granites (Maryland) and their origin 299

Grant, Sib James, Record of address of

thanks by 415

Grant, U. S., Reading of paper by 434

Greenland ice-sheet. 192

Green mountains. Glaciers of the.. 4

, Metamorph.ic conglomerate of the 117

Grit-beds, Effecl of strain on 83

Griswold, L. S., Election of 2, v,~-i

Guye, E. W. P., Donation of fossil by 217

Hague, J. D., cited on N< ne channels 270

Haines, Ben, Donation of photographs by.... 418

Hall, C. W., Donation of photographs by 417

Hall, James, cited on flic Hamilton ill

Lorraine shale 114

Medina 11:;

Niagara 113

Oneonta sandstone 93

— < Inondaga sail group 11-

Portage and Chemung Ill

— ; Tin.1 Oneonta sandstone anil its relation
to the Portage, Chemung ami Catskill

groups 8

Hammond, J. II., cited on X ene channels.. 293

Hanks, H. G., cited on auriferous gravels.... 261

Harding, G. N., Acknowledgments to 106

Harker, A., Slaty cleavage illustration of..... 77
Harrington, B. G., cited on fossii sponges... 409
Haworth. E., cited on geology of Missouri.. 17:;

Kay, Robert, Title of paper by 11

Hayden, F. V., cited on upper Missouri sec-
tion 246

Hayes, C. W., Announcement concerning

photographs by :!

— , Record of discussion by 432

— , Title of paper by 434

Hayes, R. B., Appointed J.S. Newberry State

geologist of Ohio 396

Hector, James, cited on age of Nanaimo coal-
field 246

Heer, Oswald, cited on Paleozoic plants 122,

12::. 126
Height of the Bay of Fundy coast in the
glacial period relative to sea-level, as
evidenced by marine fossils in the
bowlder-clay at Saint John, New Bruns-
wick; R. Chalmers 361

Heilprin, A., cited on age of the Tejon for-
mation 247

Heim, A., cited on cleavage 75

Helmert, F. 1!., cited on relations of the

geoid to tie- theoretic spheroid 179

Helland, A., cited on How of glaciers 197

Hendel, C. W., cited on Neocene channels.. 274
Henderson, C. W., Acknowledgments to 93

HlCKS, L. E.; Some elements of land sculp-
ture V.Y.;

Hilgard, E. W., cited on preglacial uplift-
ing 204

Hillebrand, W. I''., Analysis ofepidote by 308

11 1 mii:, G. J., cited on fossil sponges 409, 410

II 1 1 < iho.lv. (', II., cited on drift 199

granite of New Hampshire 335

• — New Hampshire lossils 366

— ottrelite schist 149

Pleistocene subsidence 367

— , Matter collected lor the Society by 375

— , Reading of memorial by 399

— , Record of discussion by 2, 410, 411

— , Studies of the Connecticui valley glacier

by 3

Hitchcook, E., cited on glacial phenomena

in Connecticui 3

IIubbs, W. H., cited on allanite 307

Page

Hobbs, \Y. 11., cited on epidote 310

New England rocks 384

— ; Phases in the metamorphism of the

schists of southern Berkshire 167

— , Title of paper by 8

Hobson, .1. B., cited on Neocene channels.... 289
HoesTjN.i >., cite. I en Greenland ice sheet..l99, 201
Iloi.t.icK. Arthuk, Editorial work upon pale-
ontologic material of Hayden survey by. 397

Hooke, B., Reference to law of 38

Hopkins, W., cited on jointing 72

Horne, John, cited on scliistosity and cleav-
age 7a

Horsetown beds and their relation to the
Shasta formation 249

of fossils 2U7

Huronian rocks north of Lake Huron 313

— (The) volcanics south of Lake Superior;

C. I.'. Van Wise 435

II iNi', T. S., Announcement of death of 372

— cited on the Hamilton in Ontario 228, 229

Lower Helderberg in Ontario 230

Portage in < Intario 227, 228

— , Memorial and bibliography of 379

Hyatt, Alpheus, idled on Oregon fossils 212

— - — paleontology of ' lalifornia 205, 220

— , Identification of California fossils by 221

1 11:1 rsoN, •!. W., eit'-d on Hooke's law 4u

Ice-sheets, Comparison of Pleistocene and

present 191

Iddings, J P., cited on allanite 306,307,311

feldspar 170

Illinois, Ancient waterways of in

— , Cor nife ions limestone of 11

— , Galena limestone of in

— , Geology of, cited od ancient waterways... lit

— , Trenton limestone of hi

Ingall, E. D., Title of paper by 409

[0WA, Ancient Waterways of II

— , Crinoids of II

— , Hamilton shales of 11

— , Niagara limestone of II

[rving, R. D., cited on chert and jasper 436

contact 327

secondary enlargement of miner-
als 171, 17H

quart/. 1'iii

— , First geologic work ol 396

Ives, J. C, Expedition by 395

Jackson, W. H.. Donation of photographs by. lie

Jamison, T. F., cited on preglacial altitude of

Scandinavia 199

Jenny, AV. P., Donation of photographs by... 418

Johnson, I.. < '.. Title of paper by 2

Jointing, origin of 72

Joy, C. A., Retirement of, as president New

Vorl-: Academy of Sciences 397

Ji'iin, .1. W., cited on secondary growth of

crystals 171-173

— , I'li'sciitat i f Murchison medal to J. S.

.\r« berry by 398

Kem i', J. F , Fleet i f, on Photograph < lom-

111 it tee II.'.

— ; Me imI of John strong Newberry by.. 393

— , Reference to bibliography of J. s. New-
berry by i"i;

Kepler, G. M., cited on Binghampton well .. 92
Keyes, C. R. ; Epidote as a prim aiy compo-
nent of eruptive rocks 305

— ; Some Maryland granites and their ori-
gin 299

— , Titles ol paper- by I ■"■ I

King, Clarence, cited on age of the earth.... 2(M

Wasatch uplift 223

Kino, C, Well in Shasta valley dug by 216

INDEX TO VOL. 4.

L55

Page

King, W., cited on jointing 72,75

Knoxville beds and their relation to the

Shasta formation 248, 249

, Relation of Horsetown beds to 211

Labrador, Glacial geology of. Iiti

— , Pleistocene changes >>i level in 421

Lacroix, A., cited on allauite 307

— epidote 310

Lark Superior, Archean rocks west of 333

Lamphere, F. W , Acknowledgments to H7

Lams sculpture, Elements of l:;:;

Laugel, A., cited on cleavage T.s

Laurentian and Huronian rocks north of
Lake Huron 313

— (The) of the Ottawa district; R. W. Ells.. 349

Lawson, A. ('..cited on mica-schists 340

the Archean.. :;:;<;

Coutchiching 340, :;n

Laurent km :;;. I

— quoted on microscopic characteristics of

gneiss 320, 321, 323

Huronian schist 322, 323

quartzite 319-321!

— , Title of paper by 421'

Lk Conte, Joseph, cited on the Tertiary.. 259, 296
1 .1 squereux, Leo, cited on Paleozoic plants... 120-

Vli, 124-126, 128
I,i:\ erett, Frank, Reference to mapping by.. 200

Libr utv, Donations to 375

Liebisch, T., cited on allanite 307

Linbgken, W , cited on relation of Mariposa

beds 223

the Tertiary of California 219

— , Reference to present survey of gold belt

by '. 222

— , Title of paper by 432

— ; Two Neocene rivers of California 257

Logan Club, Acknowledgments to. 44u

— , Invitation from the 432

Logan, Sir W. E., cited on gneissoid sye-
nite 331

granite 328

the Huronian :;1 I

Laurentian 351, 352, 355

Trembling mountain section 355

— quoted on the Laurentian 349,350, 352, 353

— , Keference to"Geolouv of Canada " by.... 426
Lew, A. 1'., Election of..... "... 2, 372

— ; Notes on the glacial geology of western

Labrador and northern Quebec 419

Lower Cambro-Silurian, Fossils of the...: 109

Ludwig, E., cited on epidote :;os

Lyei.l, Sir Charles, cited on earthquake 414

Macomb, J. N., Expedition by 395

Macoi'x, J. M., Collection of geologic data by.. 427

— quoted on Middleton island 128, 430

— , Record of discussion by 422

Maigaard, Christian, cited on Greenland

ice-sheet 193

M \i:eer, J., cited on age of the Tejon forma-
tion .' 247

Margarie, E. de, cited on land sculpture 136

Marion, A. F., cited on Paleozoic plants 124

Mariposa beds and their relation to Knox-

ville beds 222

Marstkks, V. F., Election of -1, 372

M m: 1 i\i:z group, Abandonment of the term.. 253
Maryland, Epidote in eruptive rocks of 305

— iSome) granites and their origin; C. R.

Keyes 299

Massachusetts, Glacial phenomena in west-
ern I

— , Metamorphism of the schists of 167

Mather, W. W., cited on faults 437

the Lorraine shale Ill

M ITTEHHORN, tdaejers < if the U

Matthew, G. F., cited on the Laurentian 360

Pane

Matthew, G. F., cited on Leda-clay fauna ::i;;i

Pleistocene fossils 367

McEvoy, .1 \mks. Title of paper by 434

Mc( lONNELL, II. (!• , cited on the Cretaceous... JUS

McGee, W J; A fossil earthquake Ill

— cited on drift 200

length of interglacial epoch 202, 203

— , Discussion of Connecticut valley glacier

by 5, 6

— , Reading of papers by .... J, 127, 133

— , Record of discussion by...2, '.1, 10, 411, 4'.'7. 436

remarks by '. I 10

-, Title of paper by 422, 423

McKbe, R. H., Surveys in California by 2112

McQuat, Walter, cited on gneiss :t:;l

McQueen, A. W , Acknowledgments to !ii

Meek, F. B.. cited on Vancouver fossils 246

Memorial of James Henry Chapin; W. 31.

Davis '. lot;

John Strong .Newberry; J. F. Kemp.... 393

Thomas Sterry Hunt: I.'. Pumpelly :',''.>

Merrill, F. J. II., Record of discussion by... n

Metamorphism of the Berkshire schists 167

Metasomatic phenomena in a metamorphic

conglomerate 147

Middleton islan 0, < leology of. 427

Michel-Levy, A., cited on allanite 307

Micro-sections of rocks, Illustrations from... i;,i,
152, 156, 157, 160, 163, 175, 17s

Mills, J. L., Record of discussion by 434

Mineral associates of epidote 306

— constituents of Berkshire schists 169

Maryland granites 300

metamorphic conglomerate 117

rocks. Order of crystallization of 1;, 1

Mississippi valley, Erosion of 11

Missouri, Ancient waterways in 11

— , Fossil plants from .' 11:1

— , Fossils of II

31 1 ren 1 ix, S. L., cited on earthquake Ill

Moseley, H. N., cited on Antarctic- icebergs. 192
Mount Ascutney granite, Glacial bowlders

furnished by 1

Murray, Alexander, cited on gneisses and

limestone :::.:_'

the Huronian 314, 322, 329

Laurentian 355

— quoted on characteristics of a, certain

granitic mass 328

Murray, John, cited on land and ocean
areas 180, 1 si. lsv

Nanaimo beds correlated with the Chico for-
mation 254

— coal-field, Age of 246

Nansen, Fridtjo'f, cited on Greenland ice-
sheet 193

Natural gas and petroleum in southwestern

Ontario ins

Navier, C. L. M. II., Reference to theory

of ;. hi

Neocene, Definition of the term 258

— (Two) rivers of California; Waldemar

Lindgren 257

Newberry, J. S., Announcement of death of.. 372

— cited on age of tic Chico 245, 246

Paleozoic plants 120, 122, 125, 128

— , Memorial and bibliography of 393

— , Portrait of facing I

New Brunswick, Fossils from 361

— , The glacial period in 361

New England, Glacial phenomena in .".,7

New Hampshire, Esker near I. vine 1

— , Glacial phenomena in ■':. 1

— , Metamorphic conglomerate in Green

mountains of 117

Newton, Henry, First geologic work of 396

New York, Devonian and Silurian rocks of.. 91
— , (01s and oil wells in 91

— , Two overthrusts in eastern 136

156

BULL. GEOL. SOC. AM.

Page

rs i lis. W. II., Discussion of Connecticut val-
ley by 5, 6

— ; Transmits invitation of Boston Society
of Natural History 432

Noe, G. i>k i, \, cited on land sculpture 13C

Nohdenskiold, A. K, cited on < Ireenland ice-
sheet 193

Notes on geology of Middleton island,
Alaska: ft. M.Dawson 427

the glacial geology of western Labra-
dor and northern Quebec: A. P Lqw 419

— occurrence of petroleum in Gasp6,

Quebec; II. P. II. Brumell 241

Obalski. J., cited on mini's and minerals of
Quel 243

OFFICERS, List Of Ill

Oil, Annual Ontario output of 235

— formation of Quebec 241

— in southwestern < Ontario 408

— , Number of wells in Ontario producing... 235

Oil-producing area of Ontario 226

Oil-wells of central New York 91

Ontario, Gas and petroleum in southwest-
ern 22.\ 40S

Oneonta (The) sandstone and its relations
to the Portage, Chemung and Catskill
groups; .lames Hall 8

Ottawa district, Laurentian of the 349

< Ittrelite, Alteration of, into chlorite 152

— schist. Physical and microscopic charac-

ter Of..... 149

, Thin sections of 151, 152

Oregon, Cretaceous and early Tertiary of

northern 205

— , Fossils of 250-252

— , Shasta and Chico formations in 245

< Irion, Edwakd, cited on petroliferous lime-

stone .408

— , First geologic work of 396

Over i miiisis i< in two) in eastern New York ;

N. H. Darton 436

Packard, A. S., cited on raised beaches and

terraces 421

Palawsaccus, Now genus 410

Peach, B. N., cited on schistosity and cleav-

age 75

I'i \i i , A. <'.. Election of. -

Peary, R. E., cited on Greenland ice-sheet.. 193
Penrose, R. A. F., Jr., Record of discussion

by 2

Pettee, \V. H., cited on auriferous gravel ... 259,

27 1 , 281 >

Neocene channels 268, 272-274,

277, 279, 2S1
— , Elevations taken from observations of... 263

— quoted on auriferous gravels 278

Petroleum and natural gas in southwestern

Ontario 225

— in Gaspe, Quebec 241

southwestern Ontario lus

Petrology of Berkshire schists 169

Green mountain conglomerate 147

Laurentian and Huronian rocks. .. 319-326

Maryland granites 305

■ the Laurentian and Ottawa districts.... 349

Phases in the metamorphism of the schists

of southern Berkshire; W. II. Hobbs 167

Phillips, J., cited on cleavage 77

Photograph Committee, .Mem hers of the 415

Photographs, Third annual report of Com-
mittee on 415

Pleistocene age of Middleton island ma-
terial 431

— changes of level in Labrador 421

— (Comparison of) and present ice-sheets;

W. Upham 191

— of California 297

Page

Pleistocene subsidence, Writers in support
of theory of 367

Poisson, S. P., Reference to theory of t ; 1

Portage . group, Oneonta sandstone's rela-
tions to 8

PoST-CI.AI'IAI, l'1'lle supposed) outlet of the

Great Lakes through lake Nipissing and
Mattawa river; G. F. Wright 123

Povi ell, J. W., Title of paper by 133

Procefdings of the Fifth Annual Meeting,
held at < ittawa, Canada, December 28, 29
and 30, L892; H. L. Fairchild 371

Fourth Summer Meeting, held at

Rochester, August 15 and 16, 1892 ; H. L.
Fairchild 1

Prosser, C. S.. cited on the Genesee ill

— ■ Tully limestone Ill

— ; The thickness of the Devonian and Silu-

rian rocks of central New York 91

— , Title of paper by 11

Pumpelly, Raphael, cited on the Archean... 344

contact 327

geology of Massachusetts 167, 169

Huronian 328

— New England rocks 38 I

pre-Huronian 328

— : Memorial of Thomas Sterry Hunt 379

Putnam, F. W., cited on glacial man 204

New England rocks 384

Quebec, Glacial geology of 419

— group, Fossil sponges from 409

— . Petroleum in Gaspe 241

Queen Charlotte formation correlated with

the Shasta 25:;

Queen Charlotte island, Cretaceous of... 248, 251

Raciborskt, M., cited on Paleozoic- plants I2f.

Rath, G. vom, cited on allanite 307

Ream, D., Acknowledgments to 216

Register of the Ottawa Meeting 440

Rochester Meeting 12

Reid, H. F., Election of 373, 378

— cited mi Muir glacier 196-198

— , Donation of photographs by 41<i

Relations of the Laurentian and Huronian

rocks north of lake Huron; A. E. Har-
low 313

Renault, B., cited on Paleozoic plants... 128, 129

Report of the Auditing Committee 4:;2

Committee on Photographs 416

Council '■'■'-

Treasurer; I. ( '. White 376

Reyer,"E., cited on cleavage 80

Rn ii \i;i)s, H.,- cited on Neocene channels.... 282
Richardson, James, cited on Cretaceous of
Vancouver and Queen Charlotte islands.. 248

Shasta Chico series L'ls

Rink, H., cited on Greenland ice-sheet 197

Rivers (Two Neocene) of California 257

Roehx, E. von, cited on Paleozoic plants 129

III ii hester Summer Meeting, Proceedings of

the l

Rock movements and their results 12

Romberg, J\ i ii s, cited on granophyric struc-
ture 171, 17::

Rosenbusch, II., cited on epidote 310

Ross, Sir .1 C, cited on Antarctic ice-sheet.. 192
I ii ii \i. Sin n:r\ of Canada, Acknowledgments

to II"

Rupture of rocks 13

Russell, 1. C, cited on Malaspina glacier 194.

199, 201

— , Title of paper by 139

Saint -Venant, Barre de, cited on Hooke's

lau 10

S.u.isia b.y, R. D., Appointed an auditor :i7.s

INDEX TO VOL. 4.

45'

Page

Salisbury, R. D., cited on drifl 200

interglacial epoch 203

— , Recm-d of discussion by 9, 10, 422, 423, 427

— , Title of paper by 411

S \ mis ii ink, Oneonta 8

Saporta, Gaston de, cited on Paleozoic

plants 124, 126, 127

Sardeson, F. W., Election of 373,379

s beerer, C, cited on origin of granite 307

Schenk, A., cited on Paleozoic plants.. 124, 126, 128
S 'iiiMi'Kit, W. P., cited on Paleozoic plants... 122,

123, 125-127

Schists, Chlorite i<;4

— , Metamorphism of Berkshire 167

— , Ottrelite 149

Schoenlein, J. L., cited on Paleozoic plants.. 126

Scott, W. P.., Election of 2, 372

Sections (Geologic) in southwestern On-
tario 227, 235, 237

— of gas and oil wells in central New York.. 91
Si:iii.sii,ii,m, .1. .1., cited on the granites of

Finland 337

Sei.wyn, A. R. C, Acknowledgments to 440

— , cited on Huronian 329

Shasta-Chico series 21s

— , Record of discussion by 410, 4-_':;, 432, 133

— , Title of paper by 408

Sn utit, N. S., cited on drift 199

glacial man 204

reversed flow of Mississippi ill

Sharpe, I)., cited on cleavage 77

Shasta and Chico formations 24.",, 248

Sbasta-Chico fauna compared with fauna of

Blackdown beds 254, 255

■ , Relation of the Cretaceous beds of the

Rocky mountains to 254

— series, Distribution and composition of

the -IV.)

Shasta formation correlated with the Queen

Charlotte 253

Shearing motion, Mathematics of 24

Shumard, B. F., Description of Cretaceous

fossils by _• I * .

Shi i.man, 1!., T. s. Hunt a protege of :;~9

Silurian rocks of central New York, Thick-
ness of ill

— sections in < >ntario 227

Skill, H. G., cited on granitoid gneiss :;it

Slaty cleavage, Theory of 66

Smith, E. A., Election of, as Councillor 378

Smith, \V. II. <'., Acknowledgments to 4 to

— , Record of discussion by 136

— ; The Archean rocks west of Lake Supe-
rior :::;::

— , Title of paper by , 133

Smyth, C. II., Jr., cited on the Archean. ..344-346
— , Election of. -1, :\T1

SOLMS-LAUBACH, H., cited oil Paleozoic

plants 124

Sorbv, H. C., cited on cleavage 75,. 77, 78

Spei us of fossils, New 119, 409, llu

Spencer, J. W., cited on preglacial uplifting.. 204
Stanton, T. VV., adopts the term "Shasta-
Chico series" 213

— cited on paleontology of California 205,

207, -us

u neon form able fossi Microns strata in

California -117

— , Determination of Washington fossil by... 217

— , Identification of Oregon tossils by 212

Oregon and Washington fossils by .219, 220

— quoted on California fossils 210, 21 1

— : The faunas of the Shasta and Chico for-

mation 245

—, Title of paper bj 135

Stanley-Brown, J., California sections meas-
ured by 207

— , Donation of photographs by 417

— , Election of 2, 373

as Editor :;7s

Stanley, Sib F. A., Acknowledgments to 139

Page
Stanley, Sir: F. A., Address "I welcome by... 372

Steenstrup, J., cited on flow of glaciers 197

Stevenson, J. .1., Election of. as Second Vice-
President 378

— , Question as to Oneonta sandstone and

discussion by 8

— , Record of discussion by 7

— , Reference to memorial of J. S. Newberry

by .'. I'".

Stone, G. EL, cited on Pleistocene subsi-
dence 367

Stobrs, James, fossil collection made in

California by 208, -^\ 221

Strains (Homogeneous) of rocks 13

Stur, Dionys, cited on Paleozoic plants.. 121-123
Sui:ss, E., Cited on interchange of land and

water 17a

Swallow, G. O, cited on ancient waterways.. 1 1

SWEETLAND, Sheriff, Record of address of

thanks by If".

T«NI0PTERI0D fern (A new ) and its allies ; D.
White

T.i:Nini'Tia;is missouriensis, Description of

— — , Founding of species

, Genetic relations of 121,

Talbott, .1. F., cited on N sene channels...

Tejon controversy :i4r,-

— formation, Age of.

Tertiary, Fossils of the 209, -Jin, 250-

— of California

northern California and < iregon

the Pacific coast region, Various views

on the

Thickness (The) of the Devonian and Silu-
rian rocks of central New York : OS.
Prosser

Thin-sections of Berkshire schists i7.r>,

rocks, Illustrations from 151, 152,

157, L60, L63, 17.",,

Thompson, A. H., Surveys in California di-
rected by

Thomson, SirW., cited on age of the earth...

Thomson, Sir Wyville, cited on Antarctic

ice-sheet

Tiffany, A. S. ; A ncieni u aterways

— , Title of paper by '.

Todhunter, I, Reference to "History of

Elasticity" by

Tornebohm, A. E., cited on allanite

epidote

Tit ask, .1. I )., cited on age of the ( 'llico

Carboniferous of California

Treasurer, Report of tin'

Turner, H. W., cited on basalt

distribution of the Know i lie bed.-...

fossilil'erous succession in Califor-

119
119
119
123

283

■l 1 8
247

L'.VJ

2.".7

21 15

245

nia.

Mohawk lake beds

— Neocene channels

relation of Mariposa beds

— , Reference to present survey of gold bell

by ■

Tyndall, John, Glacial studies ol

— , Slaty cleavage experiments of

Tyrrell, -l. B., Acknowledgments to

— cited on glacial man

, Title of paper by

ai
178
156,

17s

262

•jo I

192
10
10

65
307

:;lo
245
22 1
376

•-'i -.7
213

208
259
276

222

ltd

78

HO

204
III

(Jpham, Warren, cited on bowlder-clay fos-
sils '. 367

eskers I

Pleistocene subsidence ;<.,

shore lines 123

Yoldin arctica 370, 122

— ; Comparison of Pleistocene and present

il i sheets 191

— ; Com lit ions of a eel i la I ion of , I rum I in-. 9

— , Discussion by 422

458

BULL. GEOL. SOC. AM.

Pagi
Upham, Wahren, Discussion of the Conni i

ticut valley glacier by G

— , I! ird of discussions by ill, l-_'T

-, Title of paper by ". 122, t23

(Jppeb Silurian of Quebec possibly an oil-
bearing formation 241

I'm \, B, C, cited on auriferous gravels 2«3

spirit-level surveys 281

Vancouveb island coal bed, Vge of 246

, Cretaceous of -Is. 251

\ \ \ Hiss, C. R., cited on conglomerates.. 34

contact 327

Hnronian 328

pre-Huronian. 328

— - — secondarj enlargement of miner-

als '. 172, ITS

enlagement of quartz 156

term •• \ivlie m " :;::t

— , Reading of memorial by 379

— .Record of discussions by HO, L22, 432, 133

remarks by 44o

— ; The Huronian volcanics south of Luke

Superior 435

Vanuxem, L., cited on Catskillg roup 92

Lorraine shale 114

the Clinton 11::

■ Hamilton Ill

Onondaga salt group 11-

Oswego sandstone and Oneida

i glomerate 113, 114

Marcellus .■ Ill

— Niagara 113

Oriskany 112

thick ness of certain strata in New

Yelk US

Trent en 115

— Upper Helderberg ill

Utica shale 11.")

Vermont, Glacial phenomena in 4

Volcanics (Huronianj south ol Lake Su-
perior 435

Vom Rath, G., cited on ailanite 307

Win ..it. c. 1 1.. Acknowledgments to 100, 101

— , Election of, as Councillor 378

— cited on fossil sponges 109

Fulton well 106

Lorraine shale l u

New England rocks 384

the Calciferous 118

■ ( lleneilus fauna 1 Is

Pots, lam I is

Trenton 109, 115

UtiCa shale 11 1, I I .",

— . [dentification of California fossils by 221

Wallace, A. K., cited on relation of land

areas 179, IsT

W m i u \ beds of fossils 207

— formation, J. S. Diller cited on 253

"A "terways, Ancient in

\\ i isshorn, Glaciers of the 5

Westfield river valley, Glacial phe nena

in the :',

W 1 1 1 -I k\\ ks. .1. P., Announcement of election
of 373, 379

— cited on fossils from Vancouver and

Queen Charlotte islands 248,253

Queen Charlotte ten nation 254

— , Determination of fossils by 430

— . Title of paper l>y 410

White, C. V., cited on age of the Tejon for-

tion -IT

— relation of Mariposa and Knoxville

he, Is 222

Page
White, C. A., cited on relation of Shasta-
* ihico fauna to the < Cretaceous beds of

the Rocky mountains 254

Wallala beds to the Chico 223

Shasta formation 249

Tertiary of < iregon 219

the Cretaceous 206, 208

— , Identification of Oregon fossils by 212

White, David ; A new tseniopteroid fern and

its allies i pi

— . Title of paper by 10

White, [. C., cited on Paleozoic plants 122

— , Discussions by :,. 8, 408

— , Election of, as Treasurer 378

— , Pecuniary donation by 376

— , Record of discussion by •_', Ins

— , Report of, as Treasurer 376

White mountains, Glaciers of the I. T

, Porphyry pebbles from 4

Whitney, J. D., cited on California gravel

beds

Carboniferous of California 221

the Cretai us of California --'h;

Tejon fori nation JIT, 248

Tertiary of California 219

Whittle, C. L., cited on secondary enlarge-
ment of tourmaline ,. '. 176

— , Election of •_', :',',.'.

— ; Some dynamic and metasomatic phe-
nomena in metamorphic conglomerate

in the Green mountains 14T

— , Title of paper by 11

Wllliams, G. If., Acknowledg nts to 17s

Williams, II. S.. cited on Hamilton fauna.... !>.",

the lower Eelderberg 112

Upper Catskill 93

Upper Devonian 1?0

— , Discussion on < ineonta sandstone by 8

— , Record of discussion by 7

Wilson, .Artesian wells drilled by 10

Wilson, H. M., Surveys in California by 262

Wilson, W. J., Acknowledgments to 366

Win, ma l, Alexander, Donation of crayon

portrait of 375

Win, nia. i. . N. 11., Pecuniary donation by 376

— cited on drift '. 199

— transition between Vermillion and

Keewatin 340

— , First geologic work of 396

Wins, Augustus, cited on New England

leeks ' -I

Winslow, A , cited on ancient waterways 11

Williamson, R. S., Expedition by 395

Willis, Bailey, cited on'Oreti on- of Wash-
ington state JIT

Wolff, J. E., Acknowledgments to 165, 179

— cite, 1 on feldspar 161, 164, 165

— Lower Cambrian fossils us

metamorphism of feldspar... 169, 171, itj.

■ . 176, ITT

New England locks 38 I

Wooiiu \li>, R. 8., Acknowledgments to an

— . Reading of paper by '.»

W i:ie in, A. A., Collection of glacial material

by 423

Wright, G. F., cited on Muir glacier 196-198

the glacial epoch 203

— . 1! rd of discussion by 123

— ; The supposed post-glacial outlet of the

Great Lakes through Lake Nipissing

and the Mattawa river 123

— . Till- of paper by 10

/i ii i i it, P., cited ,,n Paleozoic plants..l2t, 122, 127
Zigno, Aciiille de, cited on Paleozoic

plants 126, 127 /

New York Botanical Garden Libra

il

3 5185 00257 9231