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BULLETIN

<>K THE

GEOLOGICAL SOCIETY

AMERICA

YORK
U01 >iN1CAL
QAROEN

VOL. I

W J McGEE. Editor

NEW YORK

Published by the Society

1890

( DC7JV( //. FOR 1890

James D. Dana. President

John S. Newberry, ")

j- ]7rv Presidents
Alexander Winchell, )

John J. Stevenson, Secreturij

Henry S. Williams, Treasurer

.J. W. Powell, 1

George M. Dawson, \ Members-atlargt

( 'has. II. I [iTCHCOCK, I

I ■ I : I \ I i
.1 i • I' A I )i I w i i i i i: W \~n i •.,. i .. ■ I > I

(ii)

Y
\L

CONTENTS.

Page.
Organization of the Geological Society of America; Proceedings of the Senii-
Annual Meeting held at Toronto August 28-29, 1889; Papers read at the

Toronto Meeting; hy J. J. Stevenson, Secretary 1

Organization of the Geological Society of America 1

Historical Sketch of the Organization 1

Provisional Constitution and By-Laws ' 7

Proceedings of Meeting for Final Organization held at Ithaca, New

York, December 27, 1888 9

Proceedings of the Semi-Annual Meeting held at Toronto, Canada, August

28 and 29, 1889 15

Opening Address by the President (James Hall) 15

Some Suggestions regarding the subdivision and grouping of the
Species usually included under the generic Term Orthis, in accord-
ance with external and internal Characters and microscopic Shell

Structure (abstract) ; by James Hall 19

On new Genera and Species of the Family Dictijospowjvlai (abstract) ;

by James Hall 22

The Strength of the Earth's Crust (abstract) ; by G. K. Gilbert .... 23
Bowlder Belts distinguished from Bowlder Trains— their Origin and

Significance (abstract) ; by T. C. Chambeklin 27

On the Trap Dikes near Kennebunkport, Maine (abstract) ; by J. F.

Kemp 31

The Sylvania Sand in Cuyahoga County, Ohio ; by Peter Neff... 32
Areas of Continental Progress in North America, and the Influence of the
Conditions of these Areas on the Work carried forward within them; by
James D. Dana 3U

Study of a Line of Displacement in the Grand Canon of the Colorado, in
Northern Arizona (with figures 1-12); by Charles D. Walcott 49

The High Continental Elevation preceding the Pleistocene (with figure 1) ;
by J. W. Spencer 65

Ancient Shores, Bowlder Pavements, and High-Level Gravel Deposits in
the liegion of the Great Lakes (with plate 1 and figures 1-7) ; by J. W.

Spencer

Ori-in of the Pvock Pressure of Natural Gas in the Trenton Limestone of Ohio

and Indiana; by Edward Orton

Notes on the Surface Geology of Alaska (with plato 2) ; by I. C. RUSSELL..
W Note on the Pre-Paleozoie Surface of the Archean Terranes of Canada; by
J" 2 Andrew C. Lawson "~7~7"

* i? (»>)

- -0

C\i

IV BULL. GEO] . SOC. AM.. VOL. 1

Page.
Tli. Internal Relations and Taxonomy of the Archean of Central Canada; by

&NDKKW O. LAW80M '"'

ucture and Origin of Glacial Sand Plains (with plate 3 and figures 1-4) ; by

William Morris Davis 195

Tli. P I ambrian Rocks of the Black Hills (with plate- I, 5 and figures 1-5) ;

byC. R Vah Ih-i: 203

phic Movements in the Rocky Mountains j by S. P. Emmons 245

<ial Phenomena in Canada; by Robert I'.ki.i. 287

1 1 the Pleisl Flora of Canada (with figure 1); by Sir William Dawson

and I>. P. l'KMI ALLOW -ill

Tho Value of the Term "Hudson River Group" in Geologic Nomenclature (with

figure 1); byC. D. Walcott 335

Results of Archean Studies (with ligures 1-12); by Alexander Win-
ched 357

1' -: -T( rtiary Deposits of Manitobaand the adjoining Territories of Northwestern

Canada; by J . B. TviiUKi.l 395

Sandstone Dikes (with plates 6-8 and figures 1-8); by J. S. Dillkk 111

tiary and Cretaceous Deposit of Eastern Massachusetts (with plate 9) ; by N.

443

The Stratigraphy of the "Quebec Group" (with plate 10) ; by R. \V. Ells 453

Some additional Evidences bearing <>n the Interval between the Glacial Epochs;

by T. C. Chamberlim 469

The Cuboid'- Zone and it- Fauna; a Diseu.- ion id' Methods of Correlation (with

plates 11-18); by Henri S. Williams 481

The I rous Formation in the Champlain Valley; by Ezra Brainerd and

lll.NKV M. Sl.KI.Y __ 501

: Rocks and their Fauna ; by It. 1'. Whitfield 514

i codings "' the Annual Sleeting held at New York December 26, -7 and 28,

• ; by J. J. Stevenson, Secretary 517

ion of Thursday, December 26 ' 518

obituary Notices 519

The Laramie Group (abstract) ; by J. S. Newberry ...._ 524

.hi the Eruptive Origin of the Syracuse Serpentine ; by George

ll. Williams 538

• Friday, December 27 535

Report of the Council. 535

the Tertiary Deposits of tho Cape Poar River Region; by Wil-
liam B. Clark .. 687

0 Features Parts of the Yukon and Mackenzie Basins; by

R. G. Mel 540

\ M lion in Ontario (abstract); by Rev. G. Fred-

'•'. 10 HI .11

ithorn I ii of tho A p| attox Formation (abstract);

WJMeCJ ._ 546

CONTENTS. y

page.
Session of Saturday, December 28 550

Geological and Petrographical Observations in Southern and Western

Norway (abstract); by George H. Williams 551

Cretaceous Plants from Martha's Vineyard (abstract); by David

White 554

Significance of Oval Granitoid Areas in the Lower Lauren tian

(abstract); by C. II. Hitchcock 557

Porphyritic and Gneissoid Granites in Massachusetts (abstract) ; by

B. K. Emerson 559

On the Intrusive Origin of the Watchung Traps of New Jersey

(abstract); by Frank L. Nason 502

The Fiords and Great Lake Basins of North America considered as

Evidence of Preglacial Continental Elevation and of Depression

during the Glacial Period ; by Warren Upiiam 5'):;

On the Genus Spirifera and its Interrelations with the Genera Spi-

rifcrina, Syringothyris, Oyrtia, and Cyrtina (synopsis) ; by James

Hall 507

On Pot-IIolcs North of Lake Superior unconnected with existing

Streams; by Peter McKellar 508

Constitution and By-Laws of the Geological Society of America 571

List of Officers and Fellows of the Geological Society of America 570

Index to volume 1 587

ILLUSTRATIONS.

r Ancient Bowlder Pavement of Algonquin Beach )

Plate 1— Si'ENCER: . 80

I. Modern Bowlder Pavement on Georgian Bay )

" 2— Russeil: Sketch Map of Alaska 99

" 3 — Davis: A Representative Glacial Sand Plain 2U2

" 4 — VanHise: Sections of Micaceous Graywacke in ordinary and polar-
ized Light (2 figures) 211

" 5 " Sections of Mica-slate and Museovite-biotite-schist (2

figures) 211

« 6— Diller: Sandstone Dikes in Northern California (4 figures) III

" 7 " Sandstone Dikes in Northern California (3 figures) 416

" 8 " Great Sandstone Dike on Roaring River 418

u 9— Shaler: Geological Sections on Martha's Vineyard (3 figures) 152

» 10— Ells: Map of Quebec, Levis, and Island of Orleans — 164

<' 11 — Williams: Oscillations in Devonian Sedimentation (11 figures) 487

u 12 " Representative Fossils of the Cuboides Zone (16 figures) •"><»>
n 13 " Geographical Modifications of Atrypa cuboides, Sow. (34

figures) r'""

VI BULL. GEOL. SOC. A.M., VOL. ].

Pag<

\\ \ i ■ n i i Figure I Section in Nun-ko-weap Valley ">1

•_' Section in Nun-ko-weap Valley 51

- ction on Nun-ko-weap Brook 52

I Section between Nun-ko-weap and Kwa-gunt Valleys. _ •"»:!

5 Section South of Kwa-gunt Valley 53

6— Section North of Chuar Valley 54

7 — Section in Kwa-gunt Valley 54

8— Section through Chuar Lava Bill.. 55

9— Restored Section through Chuar Lava Hill 50

10 — Ideal Section of East Kaibab Monocline 59

11 — Section across the Grand Canon at Chuar Butte 61

li! — Diagramatic Section of the Permian Monocline 64

SPEN( er: Figure 1 — Map of the Gulf of St. Lawrence showing the Course of an

Ancient ltiver 68

Speni er: Pigure 1 — Section Bhowing the Floor of a Cut Terrace 72

'_' — Section showing the Flour of a Terrace of Construction 72

3 — Section of Cut Terrace with Bowlder Pavement 7:;

1 — Section of Terrace and Bench partly concealed by a Land-
slide 73

" 5— Map of the Western End of Lake Ontario. 71

" " 6— Plan of a Barrier Beach 7'i

7 — Section extending Northward from near Flesherton 85

Davis: Figure 1 -Meal Longitudinal Section of a Sand Plain 197

2— Ideal Section of Cross-bedding 198

«i ;) — Cross-bedding at the Head of a Sand Plain 198

4— Cross-bedding at the Front of a Sand Plain 199

\'\s- Husk: Figure 1 -A Portion of Newton's Mapofthc Black Hills . 205

" " 2 Bands of Conglomerate cutting Slaty Cleavage 207

8— Thin Section of Quartz-Schist 216

4 — Part of a thin Section of Quartz-Schist ... 217

5— Thin Section of Quartz-Schist 217

Dawhon and Pen hallow: Figure 1 — Acer pleistocenicum .'!L's

\V\i : Figure I— Diagram of the Hudson Tcrrane in New York, Ohio, and

[owa ::"><)

Wu I e 1— P in ol Granitoid and Gncissoid Area- in Minnesota

and Canada ...862

2— Relations of Mica Schist and Gno'iBS, Burntside Lake :;7o

ILLUSTRATIONS.

VII

Page.
Winchell: Figure 3— Relations of Muscovite Schist and Granite, Burntside

Lake o?1

" 4 — View at Rapids below Basswood Lake 372

" 5— Schist enclosing Granulite, itself embodying Mica Schist,

Burntside Lake 373

" 6 — Hydromica Schist wrapped around Masses of Granite,

Farm Lake 373

7 — Plan of the Folding of the Crystalline and Semi-Crystal-
line Rocks in the Northwest : 378

" 8— Contact of the Animike and Kewatin Schists 386

" 9 — Relative Position of the Animike and Kewatin Schists__ 386

" 10 — Observed Contact of Animike and Kewatin 387

" 11 — Professor Irving's "Generalized and partly Idealized

Section" 387

" 12 — Unconformity of the Animike and Kewatin Schists 380

D11.

,er: Figure 1 — General Map of Northern California 412

2— Map of the Sandstone Dike District 413

3 — Section on Cottonwood Creek at Gas Point 415

4 — Crooked Sandstone Dike, 18 inches in Thickness 421

5 — Biotite of Sandstone Dike, crushed edgewise (magnified) 426

6 — Biotite of Sandstone Dike, crumpled (magnified) 426

7 — Biotite of Sandstone Bed, crushed (magnified)-. 42*1

8 — Section across the Dike Reerion in Northern California 431

PUBLICATIONS OF THE GEOLOGICAL SOCIETY OP AMERICA.

REGULAR PUBLICATIONS.

Tho Society issues n single serial publication entitled Bulletin of the Geolog-
t< \i. Society of America. This serial is made up of proceedings and memoirs, the
former comprising the records of meetings, with abstracts and short papers, lists of
:., and the latter comprising the longer papers accepted for publication.
The matter is issued as soon as practicable after acceptance in covered brochures,
which are distributed al once to Fellows and exchanges. Provision has not yet been
made foi

Volume 1, covering the work of the Society from its organization to the end of
1889, i- now complete. It comprises tho following brochures :

RnociiURE. Paces. Plates. Date.

Organization, Proceedings of Toronto Meeting and (1890)

Papers read at Toronto. J. J. Stevenson, Secretary— 1-86 1 Feb 'y 15

Origin of the Rock Pressure of Natural Gas in the
Trenton Limestone of Ohio and Indiana. EDWARD

ORTON 87-98 .March I

ii the Surface Geology of Alaska. I. C. Rus-

i.r. 99-162 2 " 13

Note on the Pre-Paleozoic Surface of the Archean Ter-
ranes of Canada; The Internal Relations and Taxon-
omy of the Archean of Central Canada. A. C. Law-

,» 103-101 " 12

Structure and Origin of Glacial Sand Plains. W. M.

Davis 1 195-202 :: " 21

Tie Pr< -Cambrian i: ka of the Black Bills. C. R. Van

Hisj 203-244 1,6 " 26

graphic Movements in the Rocky Mountains. S. F.

Emmons - 245-286 April 7

On Glacial Phenomena in Canada. Robkrt Bell 287 :il<> " :">

(ih the Pleistocene Flora of Canada. Sir William

Dawson and I). P. Peniiallow oil 334 " 9

The V"ah f the Term "Hudson River Group" in

ric Nomenclature. C. D. Walcott 335-356 " ll

rue Results of Archean studies. Alexander Win-

« i i ii.i :r>7-°.!l I " 15

Post-Tertiary Deposits of Manitoba and the adjoining

Territo Northwestern Canada. J. B. Tyrrell 395 ll<» " 17

Istone Dikes. J. S. Dilleb III 142 6-8 " '-'l

tiary and Cretaceous Deposits of Eastern Massachu-

Shaler... 148 152 9 " 21

The Stratigraphy of tl iuobecGroup." R. W. Ells 153-468 10 "

ne additional Evidences bearing on the Interval bo-

G ial Epochs T. C. Chamberlin 169 180 " 24

The Cuboidcs '/.<>w<- and it- Fauna; n Discussion of

M ' G Correlation. II. S Williams 181 500 II 18 May 7

1 Formation in the Champlain Valley.

.!• and II M . Si i.i.i . \\ ill. a Slipplc-

I l !.' and their Fauna. It.

I" Wuti mi 501 516 April 29

■ w York Meeting. .1. .1 . Si r.\ bn-
( With Index, Title-page, List of Con-
Iho Volutin- 517 598 May 27

(viii)

PUBLICATIONS. IX

1 UUKOULAK PUBLICATIONS.

In the interests of exact bibliography, the Society takes cognizance of publications
issued either wholly or partly under its auspices. Each author of a memoir receives
30 copies, and is authorized to order any additional number at a slight advance on
cost of paper and press work ; 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 at a slight advance on cost
of paper and presswork ; but these separates are biblibgraphically distinct from the
brochures issued by the Society.

The following separates of parts of Volume 1 have been issued :

Editions uniform with the Brochures of the Bulletin.

Pages 1- 86— 30 copies. February 19, 1890.

87- 98—130 "

99-162— 80 "

163-194—130 "

185-202—100 "

203-244—230 "

245-286— 30 ';

287-310—230 "

311-334—200 "

335-356—180 "

357-394—130 "

395-410—180 "

411-442—230 "

443-452—130 "

453-468—130 "

469-480—230 "

481 -500— 80 "

501-516- 60 «

517 593— 30 "

Sjiecial Editions.*

Pages 1- 6 f- 14 copies. February 20, 1890. Without covers.

19- 23 - 50 " " 13, "

23- 27 -250 " " 12, "

27- 31 -200 " " 13, "

March

26,

25,

26,

April

'•»,

12,

18,

19,

25,

26,

May

27,

— »

27,

* Bearing the imprint [" From Bull. Geol. Soc. Am., Vol. l.'l
■(•Fractional pages sometimes included.

1, XXX— Bull. Geol. Soc. Am.. Vol. 1, 1889.

Bl 1. 1.. GEOL. SOC. A.M.. Vol.. I.

Page* ;1 32 — 50 copies. February 13, L890. Without covei

32- ;;| _ -_>o "

3G- 48 —100 '■

49_ C4 —200 "

- . — 230 "

524-532 —100 '•

529-531 —100 "

533_5:]4 _ 75 «

- 540 —150 "

540-511 —100 "

544-546 — 50 "

546-649 — 200 "

55I ;,:,:; _ 75 «

554-556 — 50 "

.-,.-:, 556 _100 l!

563-567 —100 "

567-568 — 50 "

568 .-.TO —100 '*

571-586 —100 "

u 11

11 :i

17,

With covers.

18,

ii it

lav

23,

i .

Without cove

a a

a 11

11 11

1 : 11

11 11

22,

11 11

23,

11 11

With

Without

27,

With

28,

ERRATA.

All contributors to Volume 1 have been invited to send in errata found in their
contributions, and the volume has been scanned with some care by the Editor. The
following errata, deemed worthy of notice, have been detected :

Text.

Page 50, line '2-1 from top ; for " ampitheatre " read amphitheatre.

51 " 5 " bottom " " section "

section.

59 "

top

" beside.
" been.

" " besides "
59 " 2 " bottom " " heen "
70 " G " top ; transpose ub" and "s."
SO " 13 " bottom ; for " fig. 2 " read fig. 1.
" plate 1 ; the cuts should be transposed.
102, line 7 from bottom ; fur " R. S. McConnell " read R. G. McConnell.

112

127
137
152
171
181

182

181
185

192

it
247

1!
II
II
tt
<(

II
11
II

I
11

top
bottom

u
it

top

bottom
top

it
ii

5 " bottom
8 " top
249, page-head title
278, line 20 from bottom
299 " 19 " "

313

314

•>

top

bottom

u
ii
ii

I!
II

" See page — "
" report of "
" North cape "
" fine debris "
" Temiscamany "
" been raised "
" contended "
" is "
"do "
" ares "
".have "
" Harper "
" Larn "
"xxxiv, 1878"
" 107° 80' "
" Sevenson "
"G. Eld ridge"
" La Ronge "
" J. G. Hinde "
it

" Pielden "

tt
it

it
tt
tt
ti

See page 128.

report to.

East cape.

debris.

Temiscaming.

been.

have contended.
" has been.
" does.
" axes.
" had.
" Harker.
" Sam.
" xliv, 1888.
" 117° 30'.
<• Stevknson.
" (i. II. Bldridge.
" La Rouge.
" G. J. Hinde.
tt it

" Peilden.

"Proceedings Royal Dublin Society, 1878"
read Scientilic Proc. Roy. Dublin Soc,

N. S., vol. 11, 1880, pp. 13,44.

(xi)

r.l 1. 1.. (JEOL. SOC. A.M.. VOL. 1.

315,

line

In >i ii

top

for

•-.). <;. Binde

read ( • . -1 . Uinde

817,

pagi

-!..

ad title

" KAUN.K "

y\\ s a .

826,

line

from

lop

• River Range "

Rivor Rouge.

•

1 1

" pleatoc* nicum "

pleistocenicum.

" Leda river "

Roseau river.

335

!>• > 1 1 « '111

" Verrazzani "

Verrazani.

337

'• curva "

(■///■/a.

" jKiralleflu "

parallela.

342

tt fiver"

Mississippi.

.ill

lay-slates "

Clay-sla

348

'• curvatus "

meurva.

■■ 71-72"

• t

71-liL'.

399

" R. s. McConnell "

R. (i. McConnell.

101,

pagi

(-head title

tt ID ii

IN.

105,

lino

L3 from

top

•• vallaj "

valley.

" high "

wide.

152

bottom

"J. K. Wood worth "

•J. B. Woodwortb

1 '1

"p. 185"

p. 186.

•• mesaeosialia"

me8oco8talis.

.-.mi

i .

top

tt ii

:,nl

bottom

" Ezra Brainard "

Ezra Brainord.

506

" axes

axi-.

507

"base of E

base of D.

509

■■ 1848 "

1847.

513

" Brainard "

Brainerd.

" llorr "

1 [eer.

526

■ i

541

••

• Makcenzie '

Mackenzie.

• l ■

8-head Lille

■ .

0. F. VVbiqut"

(J. !•'. Wi;i..iit.

.1 'i

line

•_>

from

bottom

'• orming "

forming.

Covers.

■ . line 8 from topj for ■■ Rock " read Rocks.

•• '• pp. 237 810 •• pp. 287 310.

" " "tk>cie1 " Survey.

501 6 l.i Brainard " Ezra Brainerd.

" •■ Henry M. Seeley '' read Henry M. Seely

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA

Vol. 1, pp. 1-86. pl. 1

ORGANIZATION OF THE GEOLOGICAL SOCIETY OF AMERICA

PROCEEDINGS OF THE SEMI-ANNUAL MEETING HELD AT
TORONTO, AUGUST 28-29, 1880

PAPERS READ AT THE TORONTO MEETING

J. J. Stevenson, Secretary

WASHINGTON
PUBLISHED BY THE SOCIETY
February, 1890

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA
Vol. 1, pp. 1-86. pl. 1 February 15, 1890

ORGANIZATION OF THE GEOLOGICAL SOCIETY OF AMERICA

PROCEEDINGS OF THE SEMI-ANNUAL MEETING HELD AT
TORONTO, AUGUST 28-29, 1889

PAPERS READ AT THE TORONTO MEETING

J. J. Stevenson, Secretary

CONTENTS

Page

Organization of the Geological Society of America 1

Historical Sketch of the Organization 1

Provisional Constitution and By-laws 7

Proceedings of Meeting for Final Organization at Ithaca '.1

Proceedings of the Semi-Annual Meeting at Toronto 1 "1

Opening Address by the President, James HalL_^ 15

Revision of the Genus Orthis (abstract) ; by James Hall 19

New Genera and Species of Dictyospongidse (abstract) ; by James Hall . 22

The Strength of the Earth's Crust (abstract) ; by G. K. Gilbert 28

Boulder Belts and Boulder Trains (abstract) ; by T. C. Chamberlin 27

Trap Dikes near Kennebunkport, Maine (abstract); by J. F. Kemp .__. 31

The Sylvania Sand in Cuyahoga County, Ohio; by Peter Neff 82

Areas of Continental Progress in North America; by James D. Dana 36

Study of a Line of Displacement in the Grand Canon ;. by C. D. Walcott 49

High Continental Elevation preceding the Pleistocene; by J. W. Spencer . G5
Ancient Shores, Boulder Pavements, and High-Level Gravels (with PI. I);

by J. W. Spencer ---- "

ORGANIZATION OF THE GEOLOGICAL SOCIETY OF

AMERICA.

HISTORICAL SKETCH OF THE ORGANIZATION.*

Geological science early assumed, in America, the form of organized
activity. Various societies of local scope were initiated in the early part of

♦Prepared by Prof. Alexander Winchell, in accordance with the request ol the Council.
I— Bull. Geol. Soc. Am., Vol. 1, 1889.

_ A. WTNCHELL — HISTORICAL SKETCH OF THE G. S. A.

the present century; but the first which was destined for permanence was
the Association of American Geologists, which firsl convened at Philadel-
phia, nn the secoml of April, 1*40. Meetings were held in 1840, 1841, ami
1842, the proceeding of which were published, in 1843, in a volume entitled
"Transactions of the Association of American Geologists and Naturalists.'1
The inclusion of" Naturalists" had been determined in 1*4.'!. The number
of members was seventy-seven. Meetings were also held annually until

1847. The "Transactions" were published in the American Journal of
Science for the corresponding years. In 1847 it was voted to resolve the
organization into "The American Association for the Advancement of
Science." In such capacity it assembled in Philadelphia, September 20,

1848. Thus the "American Association " was, in its incipiency, a body of
geologists, and its first Constitution was prepared by the geologists assembled
in Boston, in 1847. After the creation of the broader organization, geology
shand with the other sciences such facilities as the Association afforded, and
on the last reorganization it was recognized (with Geography) as Section E.
With the numerical growth of the Association, the multiplication of its sec-
tions, the expanding volume of its proceedings, the increasing amount of its
general business, and the diminished opportunities for scientific work, it
began to be felt that the aims of American geology might perhaps be better
served by a return to the original status. The question was held under in-
formal consideration for several years.

The first open movement for an independent organization was made by the
geologists assembled at the meeting of the American Association at Cin-
cinnati, in 1881. A committee was appointed to consider the advisability
of the project and take requisite preparatory steps. Professor X. 1 1. Winchell
was chairman, and Professor ( '. II. Hitchcock secretary of the committee,
but DO published records preserve the names of the other members. Circu-
lars were issued by the committee, and one hundred and twenty-six answers
were received, all but two of which favored the organization of a separate
society. The committee reported to Section E al the Montreal Meeting of
the Association, in 1882. It was there voted expedien I to establish a geologi-
cal magazine. A proposed constitution for a society was presented, dis-
cussed, and laid on the table for future consideration. Some hesitation was
manifest on the part of some of the older members who had not participated

in the earlier proceedings. It was suggested, ne band, that Section E of

the Association offered .-ill the advantages of a geological society, and on the
other it was alleged thai the requirements of Canadian geologists were met
by the recently organized Royal Society of Canada. It was also suggested
thai the formation of a separate society mighl conflict with the interests of
the American Ass iciation. The whole subject, therefore, was laid over to a
subsequent occasion, At the Minneapolis Meeting of the Association, in

THE CLEVELAND MEETING. 3

1883, the consideration of the magazine and the society was resumed ; but
little was accomplished beyond the appointment of a committee to confer
with the Mineralogical and Geological Section of the Philadelphia Academy
of Natural S3iences. For various reasous the subject was not discussed at
the Philadelphia Meeting of the Association in 1884, at the Ann Arbor Meet-
ing in 1885, or at the Buffalo Meeting in 1886. Meantime the necessity of a
separate geological organization became more apparent, and some who were
at first indifferent began to express a desire that further steps be taken. At
the New York Meeting, in 1887, no action was taken by Section E, but the
American Committee of the International Congress, which existed under the
sanction of the American Association, adopted the following resolution :
" That the American Committee of the International Congress will approve
of a call for the meeting of an American Geological Congress, whose object
shall be the discussion of important geological questions."

In accordance with the judgment of American geologists present at the
Montreal Meeting, that it was " expedient to establish a geological maga-
zine," an association of seven geologists, representing different portions of
the country, began, on the first of January, 1888, the publication of the
" American Geologist," a monthly periodical, with editorial management
fixed provisionally at Minneapolis. In the June number of this periodical
appeared, from the chairman and secretary of the committee which had been
constituted at Cincinnati in 1881, a call "upon all geologists" to assemble
at Cleveland, on the day preceding the opening of the Meeting of the Ameri-
can Association, for the purpose of organizing, if deemed expedient, a national
geological society. The basis of organization suggested in this circular
restricted membership in the contemplated society to the members and
fellows of the American Association, and devolved on the Association the
election of the president and secretary of the new society. It was also con-
templated that the permission of the Association should be asked for Section
E "to hold meetings at such time and place as they may desire."

Promptly on August 14, 1888, in pursuance of the published call, the
geologists in attendance at Cleveland assembled for the purpose of discussing
the organization of a national society. Alexander Winchell was chosen
chairman and Julius Pohlman secretary. It was at once apparent that
interest in the proposed organization amounted to zeal. It was unanimously
resolved that an American Geological Society was now desirable. As to the
relation which it should sustain to Section E of the American Association,
different views were expressed; but they were speedily harmonized. I( had
often been urged as an objection to the projected Society, that it might
impair attendance at the meetings of the Americau Association. With a
view to avoiding all conflict, it was suggested, on one hand, that, the mem-
bership of the society should be coextensive with that of Section E, and on

4 A. WTNCHELL — HISTORICAL SKETCH OF THE G. S. A.

the other, that its officers should be the same as those chosen for Section E.
Some, with more zeal for the interests of geology than for those of the
Association, advocated complete independence. Both ends were reached by
a compromise which provided that the original members of the Geologi-
cal Society must be active workers or teachers of geology, who were either
members or fellows of the Association; but that, after January 1, 1889,
other persons would be eligible. The compromise further provided that a
summer meeting should always be held at the same time and place as the
meeting of the Association ; but the business meeting of the society was to
be during the winter holidays. The meeting pronounced in favor of publi-
cation, and, with this view, an annual assessment of ten dollars. A com-
mittee was appointed to draft a constitution to be presented at an adjourned
meeting on the following day. The committee consisted of Alexander
Winchell, of Ann Arbor, chairman ; J. J. Stevenson, of New York, secretary ;
Edward Orton, of Columbus ; Charles H. Hitchcock, of Hanover ; and J.
R. Procter, of Frankfort.

At the adjourned meeting, August 15, the committee presented the form
of a provisional constitution which, with slight changes, was adopted. As to
membership, meetings, and fees it embodied the instructions of the earlier
meeting; and, beyond this, contained only the usual provisions for name,
officers, and amendments, and a clause providing for going into effect. The
same committee was continued, with instructions to give the requisite atten-
tion to the completion of the organization.

It is noticeable that the action at Cleveland was not undertaken by Sec-
tion E. but by American geologists, in pursuance of a call addressed to
"all American geologists." Nor did the plan of organization contemplate
restricting the Society to persons connected with the Association. It is thus
in no way subordinate to Section E, nor to the Association, though it pro-
poses to hold an annual meeting conjointly with the Association. It pos-
sesses complete autonomy, and requires no sanction from the Association
in its attempt to represent the interests of American geology.

Thirty-seven eligible persons subscribed to the constitution before the
adjournment of the Association. Immediately after adjournment the com-
mittee of organization resumed its efforts, and by November 1 more than
one hundred names had been obtained, and the first meeting was promptly
called to assemble at Ithaca, under the hospitality of Cornell University.

An informal conference was held on the alien a and evening of December

26, and at 10 a.m., December 27, the formal meeting convened in the hall
of Sage < lollege. The attendance was small, but it was well understood that
the attendance was not an exponent of the deep and general interest fell in
the movement. The meeting was called to order and presided over by the
chairman of the organizing committee. In a preliminary statement made

THE ITHACA MEETING. 5

by the committee, it appeared that 137 persons had given their adhesion to
the Society, of whom 70 were fellows of the American Association, 45 were
members, and 22 were not connected with the Association. Of the 112
"original fellows," 89 had paid their fees, and during the progress of the
day this number was raised to 98. On a canvass of the ballots returned
through the mails to the organizing committee, it appeared that 22 others
had been elected, who, by the constitution, would become active fellows
after January 1, 1889.

When the meeting proceeded to the election of officers, it was agreed thai
candidates staudiug highest on the nominating ballots returned through the
mails should constitute a ticket. On duly balloting, the board of officers
was found elected as follows :

James Hall, Albany, President.

James D. Dana, New Haven, 1

Alexander Winchell, Ann Arbor, f Vice-PresidenU.

J. J. Stevenson, New York, Secretary.

H. S. Williams, Ithaca, Treasurer.

J. W. Powell, Washington, ]

J. S. Newberry, New York, V Members-at-large of the Council.

C. H. Hitchcock, Hanover, )

The foregoing Board, elected under the provisional constitution, formed
the Council for 1889.

A committee was chosen by ballot for reporting a revision of the consti-
tution. This consisted of Alexander Winchell, H. S. Williams, J. J. Steven-
son, H. L. Fairchild, and C. H. Hitchcock. The subject of publication
remained, by the constitution, under the discretion of the Council; but an
advisory committee was now appointed for the purpose of offering recom-
mendations to the Council. This consisted of Joseph LeConte, of Berkeley,
California; W J McGee, of Washington (Secretary) ; I. C. While of Mor-
gantown, West Virginia; N. H. Winchell, of Minneapolis, and ,W. M.
Davis, of Cambridge.

The name of the society was discussed, and, though fixed by the constitu-
tion for the present as "American Geological Society," it was generally agreed
that a preferable title would be The Geological Society oe America. It
was also formally agreed that fellowship in the society should be indicated
by the initials " F. G. S. A.," and it was recommended that this title be
employed on all suitable occasions.

It was finally voted that the Secretary should prepare a report of the
meeting, to be printed in pamphlet form for distribution to the fellows and
others, but it was distinctly provided that this should not -land No 1 '

of the recognized publications of the society. The form and style of publi-
cation remained to be fixed by the Council and advisory commitl

• '» A. WINCHELL — HISTORICAL SKETCH OF THE G. S. A.

At the close of the business, the chairman called upon the President-elect
to address the Society. Professor Hall, the veteran American geologist, still
in the possession of abundant vigor, ascended the platform, and in an
address of thirty minutes tendered the Society thanks, congratulations,

msel, and a reference to historic events stretching over a period of fifty
years. His choice as first President of the Society he considered as the
greatest honor of his life. The organization of a distinct geological society
was something he hail long desired and long expected. It was the working
geologists of America who formed the first nucleus, around which had grown
up the bulky organization of the American Association. For many years
the Association proved of great service to geology, but he had felt, for some
y.ars past, thai younger men were becoming so numerous that the day had
arrived for the pioneers to stand back. At the same time the popular char-
acter of the Association had rendered it somewhat an undesirable arena in
which to introduce the results of the profounder labors of geological investi-
gation. He counseled harmony and mutual forbearance. He understood
what provocations sometimes arise. He had sometimes himself yielded to
them, and had always thereafter suffered regrets. New circumstances
present ever new provocations; but he hoped every American geologist
would be mentally prepared to pursue a course of justice, and, if need be, of
forbearance and conciliation, in order that peace and harmony may reign
throughout our ranks. The President's remarks were exceedingly well re-
ceived, and produced an excellent impression.

In the evening a reunion was held at the private residence of Professor
H. S. Williams, where a brilliant and accomplished hostess, with her aid-.
rounded oil' delightfully the graver occupations of the day.

The (Geological Society thus began its existence strong in numbers, ability
and finances. It had already enlisted the adhesion of almost every working
Ejeologisl in the United States, and none unworthy had heeii permitted to
enter. Thus was established again an authoritative representative of
American geology, competent to know what the interests of American
geology demand, and with full liberty to act from motives lying exclusively
within its own field. May peace and a spirit of mutual consideration,
sympathy, and helpfulness reign within its borders. May the wise counsels
of it- fust President remain m- a testament to guide the footsteps of many
generations in the way- of usefulness and honor.

PROVISIONAL CONSTITUTION AND BY-LAWS.

CONSTITUTION.

Article I. — Name.
This Society shall be called The American Geological Society.

Article II. — Object.

The object of this Society shall be the promotion of the science of Geology
in North America.

Article III. — Fellows.

1. The original Fellows shall be working Geologists and Teachers of
Geology who are now members of the American Association for the Ad-
vancement of Science, who signify their acceptance of Fellowship and pay
the required fee before January 1, 1889.

2. Subsequently to January 1, 1889, all working Geologists and Teachers
of Geology in North America will be eligible to Fellowship, and will become
Fellows on signifying their acceptance of election and paying the required
fee within three months after notice of election.

3. Election to Fellowship shall be effected by means of correspondence;
and an affirmative vote of three-fourths of all Fellows voting shall be
necessary to constitute an election.

Article IV. — Officers.

1. The officers of the Society shall be a President, two Vice-Presidents,
a Secretary, and a Treasurer, who, with three Fellows, shall form an
Executive Council.

2. These shall be chosen annually by the Society at large.

3. The duties of these officers shall be those usually performed by officers
thus named in scientific societies.

4. No Fellow shall hold the office of President or Vice-President for more
than two years in succession.

5. The Executive Council shall determine the manner and material of all
the publications, and shall have the responsible control of all tin Society's
work and property, except in so far as otherwise determined by this Con-
stitution \ they shall consider all nominations to Fellowship, and their ap-

8 PROVISIONAL CONSTITUTION AND BY-LAWS.

proval shall be necessary before the submission of such nominations for
vote of the Fellows ; they shall call special meetings of the Society at such
times and places as they shall determine; and shall arrange the programme
of proceedings at all meetings; and shall perform such other duties as shall
be, in their judgment, necessary for the prosperity of the Society and the
promotion of Geological Science in North America.

<*». These officers shall be elected in the first instance by the Fellows

present at the first meeting held after this Constitution goes into effect.

Article V. — Meetings.

The annual meeting shall be held between Christinas and Xew Year, at a

place to be designated by the Executive Council. At that meeting the result

of dictions of Fellows and officers shall be announced ; and all the general

business of the Society shall be transacted. A second meeting shall be held

at the time and place of the annual meeting of the American Association

for tin Advancement of Science, the character of which shall be determined

by the Executive Council. Special meetings can be called by the Executive

Council.

Article VI. — Amendmen ds.

This Constitution may be amended at any annual meeting by the vote
of three-fourths : 1 i of all the Fellows: Provided, thai the amendment has
been proposed by five (5 Fellows, and that notice has been sent to all the
Fellows at least three mouths before the meeting.

Article VII. — Provision for Effect.

This Constitution shall go into effect when at least one hundred (100)
persons shall have communicated their acceptance of Fellowship to the
- eretary of the Organizing Committee.

/; Y- la ii

1. Dues. -Each Fellow Bhall pay to the Treasurer annually on or before
the annual meeting the sum of ten i lit) dollar-. Any Fellow in arrears for
two (2) years shall be stricken from the list, provided he shall have been

informed of his deficiency a second time by the Secretary of the Society,
after an interval of >i\ i 6 months.

•_'. Modi of Elei hon. The detail- of the election of officers ami
F( Mow- -hall be left to the Executive Council.

\mi ndmi ntts. These By-Laws may be amended at any annual meet-
ing by vote of three-fourths ( . I of the Fellows present.

PROCEEDINGS OF MEETING FOR FINAL ORGANIZATION HELD AT [THACA,

NEW YORK, DECEMBER 27, 1888.

la accordance with the call of the Committee of Organization, appointed
by an assemblage of geologists at Cleveland, Ohio, on August 14th, 1888, a
meeting was held at Ithaca, New York, on December 27th, 1888,' to com-
plete the organization of the American Geological Society.

The meeting was held in the Botanical Hall of Cornell University, and
was called to order at 10.80 a. m. by Prof. Alexander Winchell, Chairman
of the Committee. The following Fellows were present :

H. L. Fairchild, Rochester University, Rochester, N". Y.

James Hall, State Museum, Albany, N. Y.

C. H. Hitchcock, Dartmouth College, Hanover, N. H.

J. F. Kemp, Cornell University, Ithaca, N. Y.

H. B. Nason, Rensselaer Polytechnic Institute, Troy, N. Y.

W J McGee, United States Geological Survey.

J. J. Stevenson, University of the City of New York.

I. C. White, West Virginia University, Morgantown, W. Va.

H. S. Williams, Cornell University, Ithaca, 1ST. Y.

J. F. Williams, Pratt Technical Institute, Brooklyn, N. Y.

S. G. Williams, Cornell University, Ithaca, N. Y.

Alex. Winchell, Michigan University, Ann Arbor, Mich.

N. H. Winchell, University of Minnesota, Minneapolis, Minn.

The Chairman, Prof. A. Winchell, laid on the table copies of the circulars
which had been issued, and addressed the meeting, detailing the work already
done and making recommendations on behalf of the Committee.

The list of Original Fellows, numbering 98, who had already complied
with the requirements of the Provisional Constitution, Art. Ill, Section 1,
was read :

Chas. Albert Ashburner, Penn Building, Pittsburgh, Pa.

George F. Becker, United States Geological Survey, San Francisco, California.

John C. Branner, State Geologist, Little Rock, Arkansas.

Garland C. Broadhead, Professor of Geology, University of Missouri, Columbia,
Missouri.

Samuel Calvin, Professor of Geology, State University of Iowa, Iowa City, [owa

T. C. Chamberlin, President of Wisconsin University, Madison, Wis.

James H. Chapin, Professor of Geology, St. Lawrence University. Post offi
address, Meriden, Conn.

William B. Clark, Instructor in Palaeontology, Johns Hopkins University, Haiti-
more, Md.

Edw. W. Claypole, Professor of Natural Science, Buchtel College, Akron, Ohio.

John Collett, lately State Geologist of Indiana, Indianapolis, [nd.

II— Bull. Geol. Soc. Am., Vol. I, 1890. ( 'J )

10 PROCEEDINGS OF ITHACA MEETING.

Theo. B. Comstock, Professor of Mining Engineering, Illinois University, Cham-
paign, [llinois.

Geo. H. Cook, State Geologist of New Jersey, Professor of Geology, Rutgers College,
New Brunswick, N. J.

Edw. D. Cope, 2102 Pine Street, Philadelphia, Penn.

Francis W. Cragin, Professor of Geology and Natural History. Washburn College,
Topeka. Kansas.

Albert R. Crandall, Professor of Geology, Agricultural and Mechanical College
of Kentucky, Lexington, Kentucky.

WlLLIAH O. Crosby, Assistant Professor of Mineralogy and Lithology. .Massachu-
setts Institute of Technology. Boston. Mass.

Malcolm H. Crump, Professor of Natural Science, Ogden College, Bowling Green,
Kentucky.

Henry P. Oushino, 786 Prospect Street, Cleveland, Ohio.

Jamks D. Daxa, Professor of Geology, Yale University, New Haven, Connecticut.

William M. Davis, Professor of Physical Geography, Harvard University, Cam-
bridge, Mass.

J. S. DlLLER, United States Geological Survey. Washington, D. C.

W. B. Dwtght, Professor of Natural History, Vassar College, Poughkeepsie, N. Y.

Benjamin K. Emerson, Professor of Geology, Amherst College, Amherst, Mass.

Samuel P. Emmons, United States Geological Survey, Washington, D. C.

11 ERMAB Ii. Fairchild, 1'rofessor of Geology, Rochester University, Rochester, N. Y.
Albert E. Footk. 1223 Belmont Avenue, Philadelphia, Pa.

P. Max Foshat, Beaver Fall-. Pa.

Persifor Frazer, Professor of Chemistry, Franklin Institute, Drexel Building,
Philadelphia, Pa.

Homer T. Fuller, Professor of Geology, Worcester Polytechnic Institute, Wor-
cester. Ma--.

Grove K. Gilbert, United State- Geological Survey, Washington, D. C.

Geo Bird Grinnell, 318 Broadway, New York.

William F. F. Gurley, Danville, 111.

Christopher W. Hall, Professor of Geology, University of Minnesota, Minnea-
polis, M inn.

James II \i G ologist, State Museum, Albany, X. V.

Erasmus Ha worth, Professor of Geology, Penn College, Oskaloosa, Iowa.

Robert II w. United State- Geological Survey, Box 162, Junction City, Kansas.

Anoelo Eeilprin, Professor of [n vertebrate Paleontology, Academy of Natural
nee, Philadelphia, Pa.

Lewi> F. Hicks, Pro! Geology, University of Nebraska, Lincoln, Neb.

Eugene W. Hilgard, Professor of Agriculture, University of California, Berkeley,
fornia.

Robert T. Hill, Professor of Geology, University of Texas \ istin, Texas.

Chas. IF Hitchcock, Pro t of Geology, Dartmouth College, Hanover, N. II.

Levi Holbrook, P. 0. Bos 536, New York City.

Km A. Holmes, Professor of Geology, University of North Carolina, Chapel
Hill. N. ('.

Horaci « ' Hovet, 11 Park Str t, B idgeport, Conn.

Edwim E. Howell, 18 College A.vei Rochester, X. V

A i. i'ii 1. 1- II i \ i i . Boston £ Natural History, Boston, Ma

ORIGINAL FELLOWS. 11

Joseph F. James, Professor of Geology, Agricultural College, Maryland.

Lawrence C. Johnson, United States Geological Survey, Meridian, Miss.

James F. Kemp, Assistant Professor of Geology and Mineralogy, Cornell University,

Ithaca, N. Y.
George F. Kunz, 402 Garden Street, Hoboken, N. J.

Joseph Le Conte, Professor of Geology, University of California, Berkeley, Cal.
J. Peter Lesley, State Geologist, 1008 Clinton Street, Philadelphia, Pa.
AV J McGee, United States Geological Survey, Washington, D. C.
Frederick J. H. Merrill, Fordham Heights, N. Y.
Albro D. Morrill, Professor of Biology and Geology, Ohio University, Athens,

Ohio.
Frank L. Nason, Assistant, Geological Survey of New Jersey, New Brunswick.

New Jersey.
Henry B. Nason, Professor of Natural Sciences, Rensselaer Polytechnic Institute,

Troy, N. Y.
Peter Neff, Cleveland, Ohio.

John S. Newberry, Professor of Geology, Columbia College, New York City.
Edward Orton, State Geologist, Professor of Geology, State University, Columbus,

Ohio.
Amos O. Osborn, Waterville, Oneida Co., N. Y.
Richard Owen, New Harmony, Indiana.

Horace B. Patton, Assistant Professor of Geology, Rutgers College, New Bruns-
wick, N. J.
William H. Pettee, Professor of Mineralogy and Economic Geology, Michigan

University, Ann Arbor, Mich.
Franklin Platt, 615 Walnut Street, Philadelphia, Pa.

J. W. Powell, Director of United States Geological Survey, Washington, D. C.
Chas. S. Prosser, United States National Museum, Washington, D. C.
Raphael Pumpelly, United States Geological Survey, Newport, R. I.
Israel C. Russell, United States Geological Survey, Washington, D. C.
James M. Safford, State Geologist, Professor in Vanderbilt University, Nashville,

Term.

Rollin D. Salisbury, Professor of Geology, Beloit College, Beloit, Wris.

Charles Schaeffer, 1309 Arch Street, Philadelphia, Pa.

Nathaniel S. Shaler, Professor of Geology, Harvard University, Cambridge,

Mass.
Frederic W. Simonds, Professor of Geology and Biology, Arkansas Ind. Univer

sity, Fayetteville, Ark.
Eugene A. Smith, State Geologist, Professor of Geology, University of Alabama,

Alabama.
John C. Smock, Assistant in charge of State Museum, Albany, N. Y.

Joseph W. Spencer, Professor of Geology, University of G gia, Athens, Georgia.

John J. Stevenson, Professor of Geology, University of the City ..f New York, \. Y.
William E. Taylor, Teacher of Geology and Natural History, Nebraska -

Normal School, Peru, Neb.
Asa S. Tiffany, 901 West Fifth Street, Davenport, Iowa.
James E. Todd, United States Geological Survey, Professor Natural Science,

Tabor College, Tabor, Iowa.
Henry W. Turner, United States Geological Survey, San Francisco, Cal. lorn, a.

12 PROCEEDINGS OF ITHACA MEETING.

Warren Upham, United States Geological Survey, 21 Newbury Street, Somerville,

M ass.
Charles R. Vak Hise, United States Geological Survey, Professor Mining and

Petrology, "Wisconsin University, Madison, Wis.
A. W. Vogdes, Captain Fifth Artillery, Fort Hamilton, New York Harbor, N. Y.
M. E. Wahswoim'H, State Geologist, Director of Michigan Mining School, Hough-

ton, Michigan.
Charles D. Walcott, U. S. Geological Survey, Washington, D. C.
Israel C. White, Professor of Geology, West Virginia University, Morgantownj

W. \'a.
Robert P. Whitfield, Curator of Geology and Palaeontology, American Museum

of Natural History, Central Park, New York City.
Edward H. Williams, Jr., Professor of Mining Engineering and Geology, Lehigh

University, Bethlehem, Penn.
George H. Williams, Professor of Inorganic Geology. Johns Hopkins University,

Baltimore, Mil.
Henry S. Williams, Professor of Geology, Cornell University, Ithaca, N. Y.
J. Francis William-. Director of Technical Museum, Pratt Institute, Brooklyn,

N. Y.
Samuel G. Williams, Professor at Cornell University, Ithaca, N. Y.
Alexander AVinchell, Professor of Geology, University of Michigan, Ann

Arbor, Mich.
Horace V. WlNCHELL, Assistant, Minnesota Geological Survey, Minneapolis, Minn.
Newton H. WlNCHELL, State Geologist and Professor in University of Minnesota,

M inneapolis, Minn.
ARTHUR Winslow, Assistant, Geological Survey of Arkansas, Little Rock, Ark.

The Secretary (of the Committee of Organization, acting as Secretary of
the meeting), reported that a scrutiny of the ballots, received by mail from
seventy-four Fellows, showed the election of the following candidates for
Fellowship under Art. Ill, Section 2:

Wm. S. I'.avi.kv, Professor of Geology, Colby University, Waterville, Maine.
Wm. P. Blake, Mill Rock, New Haven, Conn.

K. Ellsworth Call, Professor of Natural Seience, High School, 1><> Moines, Iowa.
K. W. Ells, Geological Survey of Canada, Ottawa. Canada.
J. C. Pales, Professor of Natural History, Centre College, Danville, Ey.
Wm. M . Fontaine, Professor of Geology, University of Virginia.
A. <'. fin. i., Student in Petrography, Johns Hopkins University, Baltimore, Bid.
Edw. Gilpin, Jr., Inspector of Mines, Halifax. Nova Scotia.
II. <;. II inks, lately State Mineralogist, San Francisco, Cal.
David Honeyman, Provincial Geologist, Halifax, Nova Scotia.
E. V I) Invii.i.ikks, 711 Walnut Street, Philadelphia, Pa.

A. W.Jackson, Professorof Mineralogy, Petrography and Applied Geology, Uni-
versity I ifornia, Berkeley, Cal.
Jules Marcou, 12 Garden Street, Cambridge, Ma

P. II. Mbll, Jr., Professor of Geology, Alabama Technical Enstitute, Auburn, Ala.
G p, Mebbill, Curator, United States National Museum, Washington, D. C.
James K. Mills, 2106 Van N< - Avenue, San Francisco, Cal.
.1. II. Peret, Professorof Natural Science B b School, Wor ter, Mass.

ELECTION OF OFFICERS. 13

After a general discussion respecting the needs of the Society, a committee
was chosen to prepare a revised constitution to be submitted at the next
meeting of the Society. The committee consists of

Alex. Winchell, Ann Arbor, Mich.
H. S. Williams, Ithaca, N. Y.
J. J. Stevenson, New York City.
H. L. Fairchild, Rochester, N. Y.
C. H. Hitchcock, Hanover, N. H.

Election of Officers for the year 1889 being next in order, the Secretary
read the result of the balloting for preference as received by him from 72
Fellows, after which the Fellows present, in accordance with the Provisional
Constitution, Art. IV, Sec. 6, cast their ballots with the following result :

President. — J AMBS Hall, Albany, N. Y.
First Vice-President. — James D. Dana, New Haven, Conn.
Second Vice-President. — Alex. Winchell, Ann Arbor, Mich.
Secretary. — John J. Stevenson, New York City.

Pending the ballot for Treasurer, a recess was taken until 2.30 p. m.
Balloting was resumed immediately after the recess, and resulted in the
election of1 —

Treasurer. — Henry S. Williams, Ithaca, N. Y.

Members-at-large of the Council. — John S. Newberry, New York City; J. W.
Powell, Washington, D. C. ; Charles H. Hitchcock, Hanover, N. H.

Prof. Hall then took the chair, but owing to indisposition retired after a
few remarks, and Vice-President Winchell presided until the session's close.

The names of seventeen candidates for election into the Society were pre-
sented and referred to the Executive Council.

The following additional By-law was adopted :

Fellows of this Society are authorized to append the letters F.G.S.A. to
their names to indicate their membership in this Society.

And it was resolved, as the sense of the meeting, that Fellows of the So-
ciety should so use those letters.

The Secretary was instructed to print the proceedings of this meeting with
a complete list of the Fellows, for distribution as a circular.

The following resolution was passed unanimously :

Resolved, That the Committee on Revision of the Consiiiut inn be requested
to take into consideration the propriety of allowing all Fellows to voir by
proxy when absent from meetings of the Society.

A general discussion ensued respecting the form and character of the
Society's publications, and the Secretary was instructed to urge Fellows to
send suggestions respecting this matter to the Committee on Revision of the

14 PROCEEDINGS OF ITHACA MEETING.

Constitution. A committee was appointed as advisory to the Executive
Council in reference to the character of publications. It consists of —

Joseph LeCoNTB, Berkeley, Cal.

W J McGbb, Washington, D. C.

N. H. WlNCHELL, Minneapolis, Minn. $

I. C. White, Morgantown, W. Va.

W. M. Davis, Cambridge, Mass.

It was agreed that when the Society adjourn, it adjourn to meet at
Toronto, on Wednesday, August 28, 1889, immediately after the adjourn-
ment of Section E of the American Association for the Advancement of
Science.

The Treasurer was authorized to pay bills for current expenses on certifi-
cation by the President and Secretary.

Addresses were made by President Hall and Vice-President Winchell.
The thanks of the Society were tendered to Prof. H. S. Williams and the
Trustees of Cornell University for their courtesy and hospitality.

The rough minutes were read and approved ; after which the Society ad-
journed to meet at Toronto, on Wednesday, August 28, 1889.

PROCEEDINGS OF THE SEMI-ANNUAL MEETING HELD AT
TORONTO, CANADA, AUGUST 28 AND 29, 1889.

The Society met in Toronto University, Toronto, Ontario, on August 28,
at 12.30 p. m., pursuant to adjournment; Vice-President Alexander Win-
chell in the chair aud 53 Fellows present.

The Secretary read the report of the Executive Council, which stated that
the roll of the Society shows 175 Fellows, and that the Treasurer's report
shows a balauce of SI, 649 in the treasury.

The special business before the meeting was the report of the committee
appointed at Ithaca meeting to prepare a new Constitution ; but as that
committee was not ready to preseut its report, the Society took a recess
until 3.30 p. m.

At that hour the Society came together again, President James Hall in
the chair, and listened to the committee's draft of a new Constitution. The
chairman of the committee, Prof. Alex. Winchell, asked for instructions
respecting the insertion of a section authorizing voting by proxy. After a
prolonged discussion the Society, on motion of Mr. Robert Hay, referred the
whole matter to the committee with power.

Mr. W J McGee, Secretary of the Advisory Committee on Publication,
appointed at the Ithaca meeting, exhibited copies of the report presented by
that committee to the Executive Council of the Society. The Executive
Council was requested to authorize the distribution of copies of the report to
Fellows of the Society.

The Society then adjourned to meet on Thursday, the 29th inst., in the
theatre of the Normal School, the use of which had been granted by the
Hon. G. W. Ross, Minister of Public Instruction.

Session of Thursday, August 29.

The Society met at 10.30 a. m., on Thursday, in the theatre of the
Normal School. The meeting was opened by the President, James Hall,
who delivered the following address :

OPENING ADDRESS BY THE PRESIDENT.

Gentlemen of the American Geological Society :

It is now my duty to call you to order forthe first business meeting of the
Society, to listen to the reading of papers, a list of which is already before
you. This occasion does not seem to me to offer the proper opportunity for
making a formal address, but there may be a number of you presenl who

(15)

16 PROCEEDINGS OF TORONTO MEETING.

are not familial with the history of the past forty or fifty years, and are not
aware of the influence originally exercised by geologists in the organiza-
tion of the American Association for the Advancement of Science, from
which this Geological Society has lately emerged — not originated, for it was
the primary integral pari of that organization.

Without special reference at this time to an older geological society,
organized, a> I think from recollection, about the year 1824, and which
ceased to exist a few veins later, the first knowledge which I have of a
national or general organization for the advancement of geological science,
the pursuit of geological investigations, the harmonizing of opposing views
held by different men, and thereby reaching some system of nomenclature
upon which all could unite, was in 184<>. At that time the geological sur-
veys of Pennsylvania, New York, and Massachusetts, and of other States,
were in progress. Upon going into the field we found that our previous
knowledge and teachings in regard to the geology of the State of New York
were far from correct, and were even valueless for leading to any general
conclusions regarding the order or age of our geological formations. In this
state of affairs it was natural that we should look about us lor counsel and
assistance to those engaged in similar work, and some of whom had been
longer in the field than we had been. I would like to say in this place what I
suppose is not known to a dozen people in the country, that with au earnest
desire to procure the best available talent in the country, Governor Marcy
offered the first position on the geological survey of New York (the State
being divided into four districts) to Prof. Edward Hitchcock, in recognition
of hie services in geology. There was no sectional feeling at that time, as you
will observe from this act. All the partizanship and rancour that may have
existed among politicians were forgotten when the organization and interests
,,)' the geological survey came before the governor, and he appointed the
men whom he believed to be best fitted for the positions and for bringing to
the people the besl results from tie- new work, without regard to locality or
political affiliation. I mention this incidentally a- a matter of interest his-
torically.

Referring to our organization, we were afterwards informed that there
had previously been Bome correspondence between Prof Hitchcock and some
other geologists in regard to forming a geological society or association for
the discussion of geological questions. Without this knowledge, however,
tie Bubjecl of Buch an association was considered by the four geologists of
New York in their semi-annual meetings, which were held for the discussion

of questions arising in their own districts and their relations to the. adjacent.

districts of their co-workers. Sin. m- geological series extended into

Pennsylvania on the one hand and into Massachusetts on the other, it was
deemed \> vy important that we should know something of the experience

ORIGIN OF THE ASSOCIATION OF AMERICAN GEOLOGISTS. 17

and views of our colleagues and co-workers in these States. In furtherance
of our plans, Mr. Vanuxem entered into correspondence with Prof. Henry
D. Rogers, of Pennsylvania, and with Prof. Edward Hitchcock, of Massa-
chusetts, with a view to forming an association of such American geologists
as were then engaged in State geological surveys. This was the first and
main object, although at the first meeting persons other than those engaged
in geological surveys came into the Association.

This movement was the origin of the Association of American Geologists,
organized, in 1840, for the purpose of discussing geological questions ami
coming to some harmonious views in regard to the relations of the geologi-
cal formations we were then investigating, and thereby reaching some system
of nomenclature upon which we could all agree, and through which we
might bring the knowledge acquired before the public with some unity of
purpose and expression. These were simply the objects we then had in
view. Our meeting in Philadelphia, in April, 1840, resulted in a good deal
of discussion which reached no result. That meeting however prepared the
way for further work and further discussion upon the important questions
before us. No conclusions were reached regarding uniformity of nomen-
clature ; though some other questions of importance regarding the sequence
and extent of certain rock formations were settled by the end of the third
meeting, while others remained, and still remain, undetermined. In the
mean time the State geologists in New York were required by law to pub-
lish their reports, and since no agreement had been reached with their
neighbors they continued, for the most part, the use of the local names pro-
posed in the annual reports. The Pennsylvania reports published at a
later date adopted a different nomenclature. While, therefore, our original
purpose was not fully accomplished, much good resulted from personal inter-
course aud our earnest discussions of the then unsettled questions which
came before us.

At the end of three years (as I now recollect) the naturalists of the counl ry
desired to join with the association of geologists for similar purposes and
for bringing before their colaborers and the public in the same manner the
results of their investigations and for inviting discussion upon unsettled ques-
tions. The organization then became the Association of American Geo-
logists and Naturalists, and retained that title till 1848. Afterwards the
chemists and physicists, who had held aloof from the beginning, were willing
to join with us, and the American Association of Geologists and Naturalists
became the American Association for the Advancement of Science. This
is simply the history of events without detail ; and now after a career of forty-
nine years, when the number of geologists has increased more than fifty-fold,
we find that the time afforded for the discussion of important geological
topics is quite inadequate, and it has become necessary that some other means

III— Bull. Gkol. Soc. Am., Vol. 1, 1889.

IS PROCEEDINGS OF TORONTO MEETING.

should be devised to provide for the disposal of the ever increasing number
and importance of those questions beyond the limited time allotted to Section
E in the meetings of our Association ; for the work of the section, including
geography and geology, is so great that it is compelled to leave many of its
papers unread, and its discussions are often curtailed beyond what is desirable
and important.

Therefore, without any other object or feeling than here stated, this
American Geological Society has been formed; and I hope that every mem-
ber of this organization will feel that while acting independently in the Geo-
logical Society he still owes allegiance to the American Association for the
Advancement of Science. We can maintain our own Society, giving us more
freedom to do good work for geology, and at the same time afford to give
sufficient time, energy, and earnestness to Section E in the American Asso-
ciation, and show that the members have not lost their interest in the ques-
tions of geology coming before it, nor their desire to sustain it in its pristine
vigor as one of the most prominent sections of the American Association.

And now, gentlemen, there is no need of my proceeding farther with
this historical narration. I thought it proper to say something of it, believ-
ing that many of the younger members may not have given sufficient atten-
tion to the matter, and that it might be interesting to them to hear something
of our origin and history and the manner in which we began our work
nearly fifty years ago. At that time our entire Paleozoic series, in all its
grandeur, remained, in the minds of most persons, a chaotic mass, almost
without a recognized term to designate any of its members and entirely
without any accepted nomenclature for the whole.

Professor James D. Dana then read a paper entitled:

\l:l \- OF CONTINENTAL PROGRESS IN NORTH AMERICA, AND THE IN-
i ii EN( i. "i THE CONDITIONS OF THESE AREAS ON THE WORK CAR-
RIED FORWARD WITHIN THEM.

Remarks upon Professor Dana's paper were made by .Mr. ( '. I). Walcotl
and Professor James Hall. The paper will be found appended to the pro-
ci edings of this meeting.

REVISION OP THE GENUS ORTHIS.

Professor James Hall then presented two oral communications, the sub-
stance of which is contained in the following abstracts :

SOME SUGGESTIONS REGARDING THE SUB-DIVISION AND GROUPING OF
THE SPECIES USUALLY INCLUDED UNDER THE GENERIC TERM ORTHIS,
IN ACCORDANCE WITH EXTERNAL AND INTERNAL CHARACTERS AND
MICROSCOPIC SHELL STRUCTURE.

BY JAMES HALL.

[Abstract."]

The writer is aware that several generic names have already been proposed for
species usually arranged under the designation of Orthis. Recent investigators have
found it necessary to make farther sub-division, and to propose new generic terms.

The following grouping of the species has been adopted by the writer for a long
time, but no publication has been made. The seventy-four species which have been
especially studied seem to be very naturally arranged under the sub-divisions pro-
posed, and are submitted to the American Geological Society with the desire to elicit
information and legitimate criticism.

Unfortunately the writer has not had access to the latest publications on the Brach-
iopoda which have appeared in Europe, and therefore he does not know how far
Prof. (Ehlert and others may have anticipated the suggestions embodied in this
paper.

£> o

14
5

Pro-posed sub-division of the genus Orthis.

group, (shell im punctate) Low. Cambrian — Clinton.

" ( " ) Chazy — Clinton.

" ( " ) Chazy — Niagara.

" (shell punctate) Chazy— Corniferous.

" ( " ) Niagara — Up. Carb.

O. propinqua (Schizophoria) group, (shell punctate) Clinton— Carboniferous.
0. (Bilobites) (Dicoelosia) biloba group, (shell punctate) Niagara— L. Held.

O. occidentalis
O. (Platystrophia)
O. plicatella
0. tricenaria
O. testudinaria
O. hybrida

Species which have been studied and placed under the proposed grouping
« to be studied and placed under the proposed grouping

71
100

20 PROCEEDINGS OF TORONTO MEETIB

' ' shell impunctate.)

<>. Billingsi, Hartl J." ( ibrian.

0 P Potsdam.
0. plicifera, •• Cha

(>. borealis, Bill. . Trenton.

pad .. " & Hudson Rivei — Cincinnati group.

nuata, Ball "

11 lis, Hall....

O. | ,Mcl

0. rel Salter

8 A. Miller

<•. insculpta, Hall '•

O. Dayt ('lint. in.

<». fausta, "

tystrophia group. (Shell impunctate.)

V. biforata Chazy — Clinton.

1'. var. lynx, Eichwald Hudson River — Cincinnati group.

1' " " acutilirata, Conrad "

1". • " laticostata, James " "

P. " " crassa, •• " "

O. plicatella group. (Shell impunctat(

O. tritonia, Bill Cha

\ i. Winchell .__. .Treuton.

o. pectinella, Conrad

O. plicatella, Hall " & Hudson River — Cincinnati group.

o. Bi

O. triplicatella, Meek

[uivalvis, Hall "

<> Jamesi

ibquadi I

O. Kan Mc< !hesn< j

Whitfieldi, Winchell
1 1 Niagara.

■ ' Shell impum

Mall ._ Chazy.

< i • '.'■ Coi Trenton — Hudson Ri\ ■

0. di

(». Ball), Safford
0. merope, Bill.

1 ' I > ■ '• ■ rn. .__. \ a

REVISION OP THE GENUS ORTHIS. 21

O. testudinaria and O. el egantula group. (Shell punctate.)

O. perveta, Conrad Chazy — Trenton.

O. suba?quata, " "

O. gibbosa, Bill ';

O. Minneapolis, Winchell "

O. testudinaria, Dalman Trenton — Hudson River.

O. " var. multisecta, Meek _ "

O. " " emacerata, Hall__. "

O. " " Meeki, Miller "

O. ? clytie, Hall Trenton.

O. elegantula, Dalman Niagara.

O. planoconvexa, Hall Lower Helderberg.

O. concinna, " " "

O. perelegans, " " "

O. subcarinata, " .-- " "

O. lenticularis, Vanuxem Corniferous.

O. cyclas, Hall Hamilton.

0. hybrida and 0. Vanuxemi group [Rhipidomys, (Ehlert]. (Shell punctate.)

O. hybrida, Sowerby Niagara.

O. tubulostriata, Hall Lower Helderberg.

O. oblata„ " " "

O. musculosa " Oriskany.

O. Cumberlandia, " "

O. Livia, Bill Corniferous.

O. Vanuxemi, Hall " & Hamilton.

O. Missouriensis, Swallow Chouteau.

O. Burlingtonensis. Hall Burlington.

O. Swallovi, Hall

O. Thiemei, White "

O. Michelini, L'Eveille Knobstone.

O. Pecosi, Marcou Upper Carboniferous.

0. resupinata and 0. proplnqua group [Schizophoria], (Shell punctate).

O. circulus, Hall Clinton.

O. multistriata, " Lower Helderberg.

O. propinqua, " Corniferous.

O. Iowensis, " Hamilton.

O. Tulliensis, Vanuxem Tully.

O. resupinoides, Cox Upper Carboniferous.

Bilobites (Dicoelosia). (Shell punctate).

D. biloba, Linn. Niagara.

D. varica, Conrad Lower Helderberg.

I'll", EEDINGS OF TORONTO MEETING.

"\ \'i« GENERA \M> BPECIES OF Till: FAMILY DICTYOSPONGID-fi.
Nl.tt rORMa OF DlCTYOBPONOIDA PROM NIK ROCKS OF l UK (TiKMl MG OROUT.

11 Y JAMBS HALL.

[Abstract.]

Since the publication <»f the preliminary discussions of the genera and Bpecies of
this remarkable group of organisms, much additional material of interest has come
int'i my hands, largely from the rocks of the Chemung lct< >u j> in Alleghany and ad-
joining counties in New York. This formation has already furnished 11 of
the genus Dictyophyton, and besides, the curious basket sponge, I a, and
probable though incomplete evidences of the genera /' dictya and E

It i- now necessary to add two new genera to this number, .1
and Cryptodictya. The group proposed for discussion in my final work on the
reticulate -: ow includes L2 genera and Bub-genera represented, at present, by

16 g] Of these —

re from the Utica slate.
1 i- " " Hamilton shales.
2 l are " " Chemung group.
7 " " " Waverly.
12 " " other horizons of the lower Carboniferous.

There are at least twoother Bpecies remaining undcscrihed, and by the end of the
• , I expect to record at least 50 species.

The new Bpecies and genera comprise the following :

Dietyophyton sceptrum, Bp. n.
1 and locality. Chemung group, Alleghany county, N. V.

/ ' Jyophytc lum, n. Bp.

/■ Chemung group, Alleghany county, N Y.

/ Hctyophyto /.' i lalli, Bp. n.
/ motion and locality. Waverly group, Warren, Pa,

I > tyophytt • ','■ n.

/ I locality. Chemung group, Chemung Narrows, N. Y.

I> iyophyton Amalthea, Bp. n.
/ Chemung group, Great Bend, Pa.

/' • (Phragmodictya) Halli, sp. n.

/ I locality. Chemung group, Alleghany county, M Y.

/> phyton tomactUutn, -p. n.
/ Chemung group, Alleghany county, N 5

A' 1 1 •."!•!' n \ . gen. nov.
■
/ I bemung group, Steuben county, N i

rpTOBii ii \. gen. nov.

( i -p. n.

/ I mung gi Liben and Cattaraug tics, N. Y.

ADDITIONS TO THE DICTYOSPONGIDiE. 23

Sir William Dawson remarked, concerning the subject of the latter paper: We
in Canada, have now got as far back as the Siluro-Cambrian and Cambrian systems
in the history of the Dictyospongidas, several species of Protospongia and Gyathospongia
having been obtained from the Quebec group. We have thus got a little further
back in the series than you have in the United States. We have also another genus
of the same group, which Hinde describes under the name of Acanthodictya. Twelve
species in all are described in a paper on Fossil Sponges of the Quebec group, now in
the press for the transactions of the Royal Society of Canada. Another point to
which I would refer relates to the opinions entertained on the animal nature of these
curious forms. Many years ago Professor Hall was kind enough to send me speci-
mens of them. I had grave doubts about what they were, but could not refuse to
call them plants, because there were no traces of spicules upon them, and there seemed
to be evidences of an external membrane ; and therefore I thought they could scarcely
be sponges. They were then named Dictyophyton. A little later the intercross-
ing spicules were found, and I was shown a specimen of them in the Natural History
Museum of New York; and I was then very thankful to be able to say I had been
mistaken, and that we could no longer regard them as plants. We are, I think, very
much indebted to the President for the work he has bestowed upon these interest-
ing organisms, which constitute so marked an instance of a permanent animal type,
culminating in a very early period.

The Society then took a recess until 2 p. m.

At the appointed hour the Society reassembled, Vice-President Alex.
Winchell occupying the chair.

The following communication was presented :

THE STRENGTH OF THE EARTH'S CRUST.
BY G. K. GILBERT.

[Abstract.']

The term crust is. here used to indicate the outside part of the earth, without refer-
ence to the question whether it differs in constitution from the interior.

Conceive a large tank of paraffine with level surface. If a hole be dug in this and
the material piled in a heap at one side, the permanence of hole or heap will depend
on its magnitude. Beyond a certain limit, further excavation and heaping will be
completely compensated by the flow of the material. Substitute for paraffine the
material of the earth's crust, and the same result will follow, but the limiting size of
the hole or heap will be different, because the strength of the material is not the
same. Assuming the earth to be homogeneous, the greatest possible stable promi-
nence or depression is a measure of the strength of its material.

It is not believed that the earth is homogeneous, and with reference to the outer
portion of the crust it is known that it is not composed of homogeneous shells. There
is observational basis for the theory that the matter composing and lying beneath
continents is lighter than the matter composing and lying beneath ocean beds, and
many students of terrestrial physics entertain the theory that unit columns extending
from the surface downward have everywhere the same weight, the height of each

2 I PROCEEDINGS "l PORON DO ME] I tNG.

column being inversely as its mean density. In accordance with this theory, promi-
nences and depressions of the surl ist in virtue of a principle of equilibrium,
called isostatic* [Jnder hydrostatic equilibrium 1 1 1 «- surface of a free liquid is level ;

under isostatic equilibrium the surfa< i* a non-homogeneous solid, capabli ous

Hi »w. i- une\

There are thus two possible explanations of the inequalities of terrestrial surl
and ili may bi severally by the terms rigidity and isostasy.

In connection with :i Btudy of Lake Bonneville, a large body of water temporarily
filling a basin "t Utah during Pleistocene time,-) observational data were gathered
bearing on the question of rigidity versus isostasy.

] The Wasatch mountain range is carved from a large block of crustal material,
uplifted along a fault plane at one Bide. The block adjoining the fault plane <>n the
opp le is thrown down. Erosion is continually transferring material from the

uplifted block to the down-thrown block, and there is direct evidence that the moun-
tain is steadily rising or the valley sinking, or both. Some advocates of the isostatic
tl rv would regard this progressive relative displacement as a din of the con-

tinual transfer of load. Under this view the mountain block has less density than the

valley block, and the two are in isostatic equilibrium ; the unloading of the untain

block l>y erosion and the loading of the valley block by deposition disturb th [uilib-

riuni. and it i- restored by vertical movement on the fault plane.

An arm of Lake Bonneville occupied the valley, tilling it t<> an average depth of

500 or 600 feet, and this load of water was somewhat quickly added and afterward

..•what quickly removed. If the valley block were delicately sensitive t'> the

application of load, it should bcdepressed about 200 feet by the access of water, and

should rise a corresponding amount when the water was removed. But this did not

ir. On tl ntrary, the depression of the valley, as shown by changes occurring

along the fault plane, continued alike during the presence of the water and after its
removal. It is therefore concluded that the local transfer of Load from one orogenic
block to the other i- not the primary cause of the progressive rise of the mountain and
depression of the valley, and the question arises whether the mountain range may not
be wholly sustained in virtue of rigidity.

idering the main body of Lake Bonneville, it appears from a study of the

that the removal of the water was accompanied, or accompanied and fol-
lowed, by the uprising of the central part of the basin. The coincident f the

pbeno na may have been fortuitous, or the unloading may have been the cause of

the uprising. Postulating the casual relation, and assuming that isostatic equilibrium,
disturbed by the removal of the water, was restored by viscous Blow of crust matter,
then it app bservational data J) that the flow was nol quantitatively

sufficient t" satisfy the created by the unloading. A stress residuum was loft

to be taken up by rigidity, and the measure of this residuum is equivalent to the

of from (00 tbic miles of rook.

phenomena and theoretic considerations arises the working hypothesis
I the m if the crust is a prominenoe or a o »ncavity about

ill volume.

i mi \in Joui , Vol. XXXVIII,

■ ■ •' 1 1 1 ■ i in iho Seoond \ n ii ii nl Report of Ihi otogl-

1 ut h ill :iii|.«'nr In i« memoir on Laka Bonnei ill » in

ipni <>( ii

STRENGTH OF THE EARTHS CRUST. 25

If this hypothesis is strictly true, then there should he no single mountain mass
and no single valley, due purely to the local addition or subtraction of material,
having a greater volume than 600 cubic miles. At least four kinds of mountains and
valleys are due simply to the addition and subtraction of material : (1) mountains of
extravasation (such as volcanic cones) beneath which the pre-existent terranes lie
undisturbed; (2) mountains of circumdenudation, produced by the removal of sur-
rounding material ; (3) mountains produced by extravasation and circumdenudation ;
(4) valleys of erosion, unaccompanied by phenomena of displacement.

A large number of such mountains and valleys exist, and some of the largest
occurring in the United States have been mapped in contours by the U. S. Geological
Survey 3 so that their volumes can be computed readily.

San Francisco Mt., in Arizona, a result of extravasation, has a volume of 40 cubic
miles.

Mt. Shasta, probably due to extravasation only, has a volume of 80 cubic miles.

The Tavaputs Plateau, or Roan Mt., lying on the borders of Utah and Colorado,
and produced by circumdenudation, has a volume of 700 cubic miles.

Mt. Taylor, and the Taylor Plateau, in New Mexico, resulting from extravasation
and circumdenudation, have jointly a volume of 190 cubic miles.

The Henry Mts., resulting from volcanic intrusion and circumdenudation, have a
volume of 230 cubic miles.

The Sierra La Sal, a mountain group of the same type, has a volume of 250 cubic
miles.

The deeper portion of the Grand Canon of the Colorado, from the mouth of the
Little Colorado to the mouth of Kanab Creek, is due to the removal of 350 cubic
miles of rock.

The Tavaputs Plateau slightly exceeds the hypothetic limit; the other illustrations
fall within it.

In view of the phenomena cited, and of the considerations and comparisons ad-
duced, it is believed that the following theorem or working hypothesis is worthy of
consideration and of comparison with additional facts : Mountains, mountain ranges,
and valleys of magnitude equivalent to mountains, exist generally in virtue of the
rigidity of the earth's crust ; continents, continental plateaus, and oceanic basins exist
in virtue of isostatic equilibrium in a crust heterogeneous as to density.

Professor A. Winchell : It strikes me that Mr. Gilbert's position is pretty nearly
correct. I thought when he commenced that he was likely to discount the old doctrine
of surface inequalities existing by virtue of rigidity in the crust. I found in the end,
however, that he recognizes the validity of the old, generally received theory that
the height of mountains depends upon the rigidity of the crust. He recognizes that,
as I understand. I think that view, connected with the earlier suggestions of Sir
John Herschel and some of the later determinations of his son, is one so well estab-
lished that it would require very unquestionable facts in the line of those Mr. Gilbert
has furnished to overthrow the conclusions in which geologists generally are resting.
It is obvious, also, that there is truth in the suggestion that inequalities depend partly
for their existence upon differences in the density of the material, and so far as Mr.
Gilbert has used that principle in its application to the continental saliences of the
earth's crust, I do not know but he is entirely within the limits of probability. Not-
withstanding my adherence to the old doctrine, I am ready to admit there are certain

IV— Bull. Geol. Soc. Am., Vol. 1, 1889.

26 PKCX II DINGS OF TORONTO MEET] NTG.

ancea which may depend on relative densities. If I have oot caught correctly the

views : imi nations be will i -■ put me right.

P ■:■ ( 'n a \i itK.ui.i \ : I would like to inquire to what area Mr. Gilbert limits

the four and >ix hundred cubic mil

Mr. Gilbert: That raises a question I hare not answered to my own tion.

1 • to me that the imposition of a long, narrow ridge will be no more effec-

tive in producing deformation than a small portion of the Bame ridge, but it is not
ir whethera broad 1 Ided matter will be ve as a more compact lens

of the Bame weight.

Mr. II \ v : There is a series of effects in connection with the outcrop of the Lignite
in the upper part of the I' Formation in Kansas, which has suggested t" me

similar thoughts t<> thot I Mr. Gilbert. En pla the lignite is a usable variety of

'. need locally f"r fuel. It ie worked almost entirely by drifts into the Bides of the
bills, :m<l in ii" case have 1 known a Bhaft or well on the high prairie adjoining to
strike lignite, and in tl where the mines have had any extended working it

always thins out as it enter- the body of the hill. The lignite is the Boftest body of
material in the ridges, and it seems as if the removal of the pressure by the cutting
out of the valleys and plains has somewhat thickened it or pressed it out a little. I
do not know a single instance in which it has been pierced by a deep well on the

prairie.

P •!• Stkvknson: I would like to say a word or two incidentally. With

res] r of shear, I think we have made a mi-take in a great many cases.

The theory has prevailed, and does prevail very extensively still, that ordinarily fold-
ing has advanced bo .-lowly that, speaking in a general way. the particles of rocks

adjusted themselves and crushing was avoided. Depending on that th y I was led

into a grievous error, which might have led to the loss of several million- of dollars,
and which did lead to a loss sufficiently great to bring discomfort. After examining
the tunnel locations on the line of the South Pennsylvania Railway in Pennsylvania,
l itat d that in those passing through the Pocono sandstone, which is about 1,100 feet
thick in that region, very massive and apparently very Bolid, arching would not be
\ • dingly contracts were let for a lull double track railroad just there.

i the tunnels were made the full width. A year later I was si at for in great hi

the Pn tident of the Construction Company to come out there and what was

the matter with th< Istone tunnels. Something was very wrong. The fact of

the mal sandstone tunnel- needed to be arched more strongly than the

tunnel- in -late. In the folding the rock had been crushed into enormous wedj
which had -lipped hack and forth on each other, and naturally th'' adjustment was

■. had. That was the only shear down there, and lines which were found all along

tie the top, containing quartz, and which had been a puzzle to many

i to be the planes between these several wedges : and the tunnel

in W B I ford i intj Pa bows the condition only too well, for there one

oft a little narrower than the tunnel, and kept Bottling

rn until at la The same condition was found

in the other mountain r we cut through this sandstone ; the sandstone did not

ad : a bit ue. re than th i vhicb had 1 D orushed into small tV

menu which w< ich other and rubbi and forth until thosi

wh ounty, P but > mass of lenticular pit

m not much lai hand So the question of o which

all dep. .. my mind d to be,

STRENGTH OF THE EARTH'S CRUST. 27

Dr. J. C. Branner : I would like to ask Mr. Gilbert whether he has considered
this subject in connection with the subject of glaciation, and whether he believes the
weight of ice has anything to do, or much to do. with the northward depression of this
country during the glacial epoch.

Dr. A. C. Lawson : I would like to ask "Mr. Gilbert whether he included the
greater inqualities or the less inequalities.

Mr. Gilbert : I will speak first in reference to the matter of shear, referred to by
Professor Stevenson. The generalization, based on many observations, that the
material of the earth's crust, under suitable conditions of pressure and confinement,
yields to shearing stresses by flowing, finds its exception near the surface, for there
the conditions of confinement do not compel flow, but permit fracture ; and it may
be added that the result is affected also by differences in the strength and texture of
various rocks. But at a great depth, the rock subjected to shearing strain is held
closely in its place and cannot part asunder, and the result is a diffused shear, or flow.
I conceive that in a general way the phenomena of fracture are quite superficial, be-
longing to a tract extending five to ten miles downward from the surface, and that
the phenomena affecting the larger problems of terrestrial physics are phenomena of
viscous flow.

With reference to Dr. Lawson's question, which possibly I do not fully understand,
I would say that I believe a broad observational basis underlies the general propo-
sition that the ocean beds are heavier than the material of the continents. The data
have been ably discussed by Pratt, Fisher, and Faye, and the mathematical researches
of George Darwin appear to me to demonstrate, not, indeed, his conclusion that the
earth is immensely rigid, but the fallacy of his postulate that the earth is homoge-
neous as to density. Moreover, as he himself points out, we have a very decided inti-
mation, in the grouping or bunching of land masses on one side of the earth and of
the ocean on the other, that the distribution of terrestrial densities is not symmetric.
If it were symmetric, the center of mass would be the center of figure, and the oceanic
waters would be drawn as much to one side as to the other.

Dr. Branner refers to the bending down of the earth's crust by the weight of the
great ice sheet. I regard that hypothesis as most valuable, and one that will stimulate
investigation. It is too early yet to accept it or reject it. I may say that it is my
own working hypothesis, but I see the opportunity to gather an immense mass of
material pertaining to the subject, and until that material has been gathered it will
be unwise for us to tie ourselves to any one theory.

The substance of the next paper read is contained in the following
abstract :

BOULDER BELTS DISTINGUISHED FROM BOULDER TRAINS — THEIR ORIGIN

AND SIGNIFICANCE.
BY T. C. CHAMBERLIN.

[Abstract.}

For obvious reasons, boulders were among the first phenomena of the drift to attract
attention, and occupied a large share of consideration in the earlier days of investiga-
tion of glacial phenomena. In recent years attention has been more largely directed

PROCEEDINGS OF TORONTO MEETIS

the drift. Bui a has turned again to a study of certain

phases of the distribution of boulders. This has led to some distinctions and cla&sifi*

of importance upon the working out of glacial phenomena
i nation of the methi il action. Two leading types need dis-

criminatioi ulder trains, and (2) boulder belts. Boulder

train- take t h--i r . > r i lt ' " from knobs or prominences of rock which lay in the path

ffbouldt . ly and abundantly to the over-riding i

movement, but the boulders are not carried for-
ward in They may therefore appropriately be called boulder
fun- i kind, or at least of the few kind- repi I by
nt knob. They usually grow smaller and more worn as traced away from it.
lingle with the underlying drift, and in thi- respect differ from the l>"u'.

bell tly to b( nsidered A part of the significant !' these trains has bi

1. hut much additional significance remains t<> !"• developed. Special investiga-

by Professor Shaler, and at tli«' west by 1' -• - Hindi

suits of which cannot here be appropriately given.

Tin- boulder belts differ from tin- boulder train-, in that they lie transverse to the

direction ol . movement. Thev arc also contrasted with tbem in that the

boulders, insl f being of one or a few kind-, arc of many kinds, and, instead of

being derived from somi source, came from distant Bources. The boulder b

that have 1 n especially studied by myself are found in Illinois, Indiana, and

Ohio. The boulders of these belts were derived almost exclusively from the crystal-
line or Archroai to 500 miles to the northward. There i- an almost com-
:' boulders derived from the intermediate I ' ;oic rocks, although such
boulders occur in abundance in the moraines with which the boulder licit- arc
ind in tin' drift Bheets and gravel hill- with which they arc connected,
baracteristic i- the fact that the boulders arc superficial, and do ma
mingle deeply with the underlying drift, as i- the case in the boulder fan-.

listribution, the boulder belts have been found to coincide closely or nearly

with terminal mora which Btrongly suggests that they were deposited by

th<- margin of the ice that formed the moraine-. The solution of the problem pre-

ted by i • der helt- may he found in an analysis of terminal moraines. A

I - material at il- margin in three way-: il) It pushes matter forward

mechanically, ridging it at it- edge, forming what may be termed push moraii

lacier may fail to carry forward to its actual extremity the material which it
(i it- base, and this may lodge under the margin, forming a Bub marginal
imulation which may !»• called a lodge moraine. \ glacier carries forward

the material embraced within the ice or borne on it- top until it reaches the extn

margin, when it i- dropped, forming what may hi- called a dump moraine.

■older I ■ held to belong to the last class. It i- believed that boulders

from the high hill- of the Archsean highlands at - distance up in

and that these were bori ward in tin- une

until t: bed the margin, where they were necessarily

[fth : ::■. il follows as an important inference that the

'i of the ire .11, i . the -in lace, (, , r jn that ra-e the ahuiidalit

ed with the foreign drift, which i- luously

I > the doctrine advocated by Bome that, owing to

'• frontal r< arrying boulders up to heights above

BOULDER BELTS AND BOULDEB TRAINS. 20

Professor A. Winchell : Some of the phenomena to which President Chamberlin
alludes are well known within those regions that have become familiar to my own
observation, and particularly within the lower peninsula of Michigan. I have
attempted to explain the absence of fragments of Corniferous and Niagara limestones
between their northern out-crops and the southern boulder areas by the fact that they
are of a calcareous character. We have, for instance, about five hundred definable
species and varieties of Archaean boulders, and these boulders have been transported
from the regions about Lake Superior, let us say, to the north, and to the south probably.
But we have very few boulders derived from the limestones which out-crop in the
vicinity of Mackinaw and Drummond Island, and the reason seems to me obvious.
The limestones resist the destruction which has been incident to the movement of
these boulders far less completely than the Archaean fragments do ; the limestones
have been worn out or dissolved, and have disappeared ; but the Archaean boulders
have endured the transportation, and hence they are with us. I should think per-
haps a consideration of such facts should enter into President Chamberlin's conclusion
in reference to currents of boulders that originated from remote points, and those
others from the immediate vicinity in which the boulders are discovered. It might
be said that there are indeed trains of calcareous fragments, large and small, but
particularly small, of a local character that have been derived from the formations
over which the glacier has passed within a distance of five or ten miles ; but speaking
of boulders of remote transportation, the limestone boulders are few and the Archaean
boulders are many.

Professor G. P. Wright : This paper is of special interest to me because it brings
to view familiar phenomena in portions of the country which I have not visited. My
own observations have been, to a very considerable extent, on the extreme margin of
the glaciated area, and certain phenomena which occur there seem to be analogous, if
not altogether identical, with those described by President Chamberlin. What Pro-
fessor Lewis and myself denominated the '-fringe " seems to correspond very closely
to these bands of boulders in front of the larger deposits. For a time this " fringe "
was neglected by us, but as our examination progressed we came to see that there was
never, or at least very rarely, a piling up of material at the very margin, but that the
piling up occurred somewhat back of the extreme margin. We concluded, both from
the nature of the case and from the facts under observation, that the rapidity of
motion in the ice, which is well known to be greatest near the middle portion of the
current, continually decreased up to the very margin, where of course there was a
complete cessation. This would result in what we uniformly found, namely, that
there were very generally boulders thrown over to a considerable distance beyond
other marks of direct glacial action. The appearance was as if they had been carried
over on something corresponding to breakers upon the seashore successively advanc-
ing on each other. Probably the advance of the ice-front was interrupted by periods
of rest, allowing moraine material to accumulate at various stages of its progress.
With every further advance the ice would rise and flow over this moraine and rework
the material and drag it along underneath. Finally, at the extreme margin, we have
this fringe of boulders from which the ice retreated permanently. If there were
periods of cessation in the retreat, wherever a line of equilibrium was established
this accumulation of moraine material, with a fringe in front of it, would take place
in reverse order and be left for permanent inspection. Thus the bands of boulders
of which President Chamberlin has given such an interesting account would seem to
be a series of fringes to what I should call the " moraines of retrocession."

30 PRO< EEDINGS OF TORONTO MEETING.

Mv observations upon the Muir glacier, in Alaska, confirm this view of the case.
\\ here the ice projects upon the mainland there is no precipitous wall as where it
del nt" the water .>t" the inlet, but the ice gradually diminishes in amount and

I*.. rni- an incline] plane ; and for a mile or more the debris borne upon the surface of
the glacier is carried over the incline of the ice-front and deposited upon it to such a
. I • • 1 . 1 1 1 as almost wholly to ( II re is an instance of the way such accumula-

tions take place in an actually retreating ice-front. Were the ice t<> re-advance, in-
ishing this material along in front, the upper strata would move over it.
phenon onected with the lifting of boulders in the ice Bhould be con-

in this .-anie connection, [n our report upon the glacial boundary in Penn-
vania, mention is made of large numbers of boulders on the top <>f Kittatinny

mountain which must have 1 n brought from Ledges whose out-crop is several hun-

t lower. Prom the direction ol the strisa, Professor Lewis supposed they must
have come from Godfrey's Ridge, which is a thousand feel lower than the Bummit of

Kittatinny mountain, and not more than twelv ■ fifteen miles distant. Professor

1. rs that the rock of which these boulders consist is nowhere found in pli

than 500 feet below their present situation.
1 have noticed also the absence of sandstone, -hale, and limestone boulders from
the marginal belt, but accounted for it by the same considerations which Professor
Winchell has presented, namely, a survival of the fittest. The Archaean rocks are

ter fitted to survive the transportation than rock- of a softer nature and than th
which a susceptible to dissolving agencies.

r jsor C. H. Hitchcock : It is quite exhilarating to an eastern man to hear about

the transportation of these boulders bo many miles. It is with great difficulty we can

find anything that has gone more than forty or fifty miles. „,, the question can be studied

to 1" tt' r advantage in the west than in the east. There u one point 1 wish to ask Pro-

l lhamberlin about. I underst 1 him to refer to the transportation of material

in the upper part of the ice as different from that lower down. 1 desire to know if it

i- a common thine; to make out that the upper part of a glacier is transporting ma-
terial in an altogether different direction from that in the lower. In reference to
boulder fans, I think the term is a very happy expression j it reminds me somewhat
of a similar dispersion we have in the east, and I thought it possible that the scatter-
ing of the fragments could 1 xplained by the transportation of the upper part differ-
ently from the lower.

tmple is what I have described in the New Hampshire report, the boulders
rting from Bit. Ajcutney, in Windsor, Vermont, an isolated peak about 8,000 feet
ai. I onnecticut river. Its material is a peculiar granite not easily con-

founded with an\ other rock. The disposal of the boulder has been recognized on radial
line - with each other, and the greatest distance of trans-

portation is fifty mill

.i.i n : The observation of Profi r Wright regarding the trans-
portation of boulders from a lower to a higher elevation d nol m to me to appeal

but tl rdinary laws of fiowage. Boulders within a current of ice

pended in a current of water; they are merely material car-

»n. Tin- material rises and falls according to the inequalities of the

cried near the bottom, and if it is carried near the

anoral declii f the surfa N ling over the weir

, .v.-tneiit, .mi ..I those foil ad
■ ■ ai Haul glacier,

BOULDER BELTS AND BOULDER TRAINS. 31

of a dam may lodge on its crest. So, boulders going over a mountain range may
lodge there, having beSn carried up by the natural laws of basal flowage. This basal
flowage does not affect the general course pursued by the current. It is a very
different proposition from the general doctrine of a rise of current.

In respect to the fringe, I cannot take the time to say what I would be glad to say
on the subject; but I regard the fringe in western Pennsylvania as the edge of an
old drift, which has there just escaped burying. Traced further west, we find an
attenuated drift border for hundreds of miles; we have similar phenomena in the
carrying of boulders far out beyond any considerable mass of drift, in some instances
very many miles. I may state that along this border from Ohio westward to the Rocky
Mountains, we have practically nothing on the edge of the drift that I should denom-
inate a terminal moraine. We have, of course, a termination of the drift; but no
accumulation such as we have been accustomed to designate a terminal moraine. In
the latitude of Bismarck boulders reach westward of any definite terminal
moraine to the extent of forty miles, and in the latitude of Pierre there is an exceed-
ingly attenuated distribution of boulders, stretching out a dozen miles or more be-
yond the thicker distribution on the east side of the river. In the immediate vicinity
of the Rocky Mountains, after striking the first boulders from the northeast, I had
to travel two hours before finding any others or any signs of northeastern drift. So
this phenomenon of attenuated distribution of boulders has a very wide range, and
cannot be accounted for, I think, by anything in the line of the suggestions of this
paper or of Professor Wright, unless we fall back upon the general proposition that
these boulders were transported in the ice, and borne out beyond the point where the
ice had the power to push along its subjacent debris. I do not look upon the fringe
as being in a proper sense a fringe. I look upon what was called a fringe in western
Pennsylvania as the attenuated edge of a drift formation.

In regard to the transportation of boulders within the ice in different directions
from those transported on the face of the ice, I have no considerable mass of data
that would answer that question in the affirmative. In the region I have studied the
transportation of materials has in general been in practically parallel lines; I have
not been able to determine that the englacial currents of the ice were in any essential
sense different from those on the surface. I think in general they moved in a common
direction. If there were cross-currents, I think they were quite subordinate in the
interior region.

The following paper was then read by Mr. C. D. Walcott :

STUDY OF A LINE OP DISPLACEMENT IN THE GRAND CANON OF THE

COLORADO, ARIZONA.

The paper will be found appended, printed in full.

The communication represented by the following abstract was then pre-
sented :

ON THE TRAP DIKES NEAR KENNEBUNKPORT, MAINE.

BY J. F. KEMP.

[Abstract.]

The paper opened with a brief reference to the geological reports which touch this
region (those of Maine and New Hampshire), and showed that the published material

32 PROI EEDINGS OF TORONTO MEETING.

was meag r. Th( ml ilogy was then outlined. The rocks are metamorphic

quartzites, slates, it rata, standing vertically and penetrated with bosses of

granite and dikes of trap. A map drawn to scale illustrated their distribution. Men-
tion was also made of the neighboring rocky promontory of Bald Cliff, and this was
likewise ill by a map. The microscopical characters of the massive ruck.- were

bed at length. The granite was ti r- 1 taken up and Bhown t" be a normal
granite in the while in the dikes it approximates h granite-porphyry with

sely crystalline ground-mass and very large phenocrysts. The occurrence
ein-flllings on theb irders of the granite, consisting of quartz, feldspar, tourmaline,
and muscovite was cited as evidence of fu ma role action.

The dike- were next treated, some seventy-five or more different ones having been
studied. They were shown to In- noncrystalline and porphyritic examples of the
oli vine-diabase series, although some departed more or less from the type. Their

mineralogical c position was discussed at length, the most interesting features being

the occurrence of brown basaltic hornblende in one or two, and the approximation of
the dike- t<i typical camptonites. Some discussion of this latter group followed'
Attention was also given to the structure of the dikes in broad and narrow examples,
and on edges and in center. While, in general, in the narrow dike- and on the ed
a porphyritic facies is to be seen, and in the centers an approximation to granular struc-
ture, nevertheless, some of the broadest examples are porphyritic all aero-- and some of

the narrower ones more granular ; also boi f the very narrow dike- are ipiite holo-

crystalline, with relatively large phenocrysts of olivine. Three principal types were
made out in all : the olivine-diabase, the augite-porphyrite, and the melaphyre, with
hornblendic and more randy biotitic departure- from the same. One or two analj
were appended : and the paper closed with a brief discussion of the related dike roi
hitherto described in this country, ami they were shown to he principally of diabase
affinities. A. tabulation of the Eennebunkport dike- by numbers which referred t" the
map, with their width- and petrographical determinations, concluded the contribution.

In the absence of the author, the Secretary then read the following paper:

lilt BYLVANIA SAND IN CUYAHOGA COUNTY, OHIO.

T.V PETER Nil i .

Unquestionably the Sylvania sand is found in the well drilled by the Cleveland

Dg M I Co at their work- in Newblirg, near Cleveland. Cuyahoga county.

Ohio. This sand is quartzose, bright and sharp, a good glass -and. It- position is

in I nd it- pr nee here, however anomalous, i- unmistakable. It

'Meet below the mouth of the well, and is about forty% feet in thickm
I quote from I' I Orton, State Geologist, Geological Survey of Ohio,

Vol.

rell-head is aboul ty-fivefeel below the bottom of the Berea grit, and

Limestone wai reached at I860 feet; -ami at I860
t.. I" !' 0 of the latter: " It is a sharply crystalline, unworn

: which many of the grains are unusuallj t. It matches well in pi

tion i" the Sylvai I . . . This, it will be borne in mind, is no

• • buried under 160 or 200 !<■• t of

THE SYLVAN!. \ SAND IN OHIO. 33

the Lower Helderberg limestone. If this Cleveland sand is not the equivalent of the
Sylvaniasand, it is obviously a similar deposit."

This Rolling Mill well reaches the Clinton red limestone, at about 3050 feet, bein°-
fully 1000 feet above the Trenton limestone. This well demonstrates the existence of
vast rock salt deposits, which show an original depression in the surface here at that
age.

There is a well bored on the Jewett farm about one and one-quarter miles south of
the Cleveland Rolling Mill well. It is on ground fully one hundred feet above the
mouth of the Cleveland Rolling Mill well. This well is located above the Berea
Grit, southeastwardly from the quarry, near the Insane Asylum. At 1414 feet it
was through the Erie and Huron shales and struck limestone. The limestones and
shales below this are similar to those in the Cleveland Rolling Mill well. At 1720
feet salt water was struck ; at 1780 feet, or two or three feet in the Sylvania sand, a
supply of gas was found, and the well was drilled no deeper. This was in July, 1888.
Allowing for difference in elevation between this well and the Cleveland Rolling
Mill well, the sand is found at about same depth. This well has not been drilled
through the sand. It is cased, but makes about eight gallons of salt water per day.
It yields, I should judge, about 150,000 to 175,000 cubic feet of gas per day, and has
continued to do so excepting when the salt water has been allowed to accumulate.
The gas has the general characteristics of the Pindley gas, with perhaps not
quite so much sulphureted hydrogen in it. I did not see the [pressure gauged,
but was told at the well that on one occasion it was, in half an hour, 225 pounds and
rising. The same parties bored another well on the Jewett farm, locating it about
500 feet south of the other and on about five feet higher ground. Its drillings are
the same as the other two wells previously referred to ; but this well was bored through
the Sylvaniasand, which was about thirty feet in thickness and drilled about 50 feet
below the sand, in all about 18G0 feet. In the sand in this well but very little gas
was found. From 1720 feet, veins of salt water were met. This well was not suc-
cessfully cased, and on reaming it for re-casing, in July, 1889, the tools became fast-
ened in the well.

Still another well has been put down during the past year, which gives some addit-
ional interest to the Sylvania sand. It is located in Euclid township, near what is
known as " The Old Salt Works," on the Smith farm, and is about half a mile from
the shore of Lake Erie. It is about thirteen miles northeast from the Cleveland
Rolling Mill well, and not far from the town of Nottingham, in Cuyahoga county,
Ohio. The mouth of this well is from 60 to 70 feet above the level of Lake Erie.
It struck limestone at 1168 feet, salt water at about 1470 feet, and found the Sylvania
sand at 1540 feet, with no gas ; found this sand rock 50 to 75 feet thick, and very sharp
and fine grained sand. Well not cased and abandoned at 1685 feet deep.

Here, then, we have four deep wells, whose geological developments are similar and
conformable one to the other. The measurements are as accurate as I could obtain
from the parties in charge of the wells. These four wells do not encourage deep bor-
ing in the hope of striking, in Cuyahoga county, a pinnacle of the Clinton lime-
stone which is found petroliferous in some parts of the State of Ohio, and much less
in the hope of finding the Trenton limestone in condition for either gas or oil.

The Jewett farm well, which is producing the gas from the Sylvania sand, in-
dicates, however, a new horizon in which gas and perhaps oil may be stored. By
reason of some natural connection with the petroliferous formations in the Clinton

V— Bull. Geol. Soc. Am., Vol. 1, 1889.

3 I PRO< EEDINGS OF TORONTO Mill IN'..

and Trent. >n series, it may prove the receiver <>r Btore house of large, continuous
supplies. It i- :i horizon of line grained -and. which will slowly give out its
umulations, so that it- wells will be of moderate capacity but long-lived. A
as >>f such moderate Bized wells will probably produce a Bupply of considerable
value. There i- certainly no use here in drilling entirely through the Sylvania sand.
Salt water is found both above and below the sand.

II w far this Sylvania Band extends is not developed. It has not, I believe, I >< - * - r 1
encountered in any of the deep wells south of Cuyahoga county. That its general
trend i- northeast at anangleof about 46 degrees, will, I think, he demonstrated by
the drill. Previous to the Carboniferous age there was unquestionably a dividing
ridge, or slight anticlinal, through this part of what i- now Cuyahoga county, which
in a measure divided the great ocean of the lake region from the Appalachian sea.
I nformable with this ridge or elevation, the Sub-Carboniferous formation- were
more or less affected, giving rise to the present position and elevations of the Sub-
Carboniferous series ; notably of the Bcrea Grit, which may be taken as the index
stratum of this great series. Now, starting at the Cuyahoga river and going north-
eastwardly, this Berea Grit rises above the level of Lake Erie to about 850 feet in
Euclid township, where the tops of the hills are higher, and on Euclid creek there
are fine ezp and in the same general course northeastwardly toward Painesville

this zig-zag ridge or water-shed continues. There are well-marked places indicating
that this ridge was a shore line. The Berea Grit, a hard sand, is found tapering
out to a feather edge, and can he traced on its dip south to a thickness of thirty feet
in a few miles, and is not cut otf by glacial action. Again, many of the gullies three
to four hundred feet deep (Mi the general strike of the out-crop of the Berea Grit,
Btrongly indicate that this rock or shore line formed a harrier to the ice sheet, and
the cut took place nprtheast to southwest along the edge of this shore line, giving the
present configuration to these deep gullies.

I argue from what I have thus briefly given, that there i- an elevation bo covered
atures and peculiarities of the present Burface, ami that this ridge has

on it the continuation of the Sylvania sand. How far north ami SOUth, or {,, what
extent toward the aortheast it continues can only he determined by boring. But that
it i- here, and that it lie- under Euclid township at Buch an elevation and position as
to make it a gtore bouse for gas ami oil, I have no doubt. A few well- judiciously
put down would triangulate, this section ami determine the interesting question
whether this -ami i- in position and a Btore-house for holding the gas and oil rising
from tie- underlying 2 200 feet of limestones and shales. If -■>. this -ami would bear
•incident similarity to the horizon of the Berea Grit a- to it- location ami use
in being superincumbent t" gas ami oil producing formation- ; for the Berea Grit lies
above the Huron Shales, ami through the i utii 1 \ i ii i t ..!' Erie Shales gas ami oil

PROCEEDINGS OF TORONTO MEETING. 35

The Secretary then read two papers, in the absence of the author, under
the following titles :

THE HIGH CONTINENTAL ELEVATION PRECEDING THE PLEISTOCENE PERIOD.

BY J. W. SPENCER.

ANCIENT SHORES, BOULDER PAVEMENTS, AND HIGH-LEVEL GRAVEL DE-
POSITS IN THE REGION OF THE GREAT LAKES.

BY J. W. SPENCER.

These papers will be found appended to the Proceedings of this meeting.

After some remarks from Vice-President Winchell, the Society adjourned
to meet in the American Museum of Natural History, New York city, on
December 26, 1889, at 10 a. m.

AREAS OF CONTINENTAL PB0GRE88 IN NORTH AMERICA,
AND THE INFLUENCE OF THE CONDITIONS OF THESE
AREAS ON THE WORK CARRIED FORWARD WITHIN
THEM,

r.V PROFESSOR JAMES 1>. DANA.

It has 1 < > 1 1 lt been recognized that the continent of North America has its
nucleal area of Archaean ruck- ; that the nucleal V has the same courses
in it- general outline as the continent ; and that then- are ranges of Archaean
ridges, more or less interruped, approximately parallel to the outline of the
V : among them, one along the Appalachian chain, and another along
much of the Rocky Mountain chain. Further, the positions of the ranges
of the Appalachians and the Rocky Mountains were, in 1875, made by me
the basis of a division of the continental surface into (1) an Eastern Border
region, east and northeast of the Green Mountain range; I 2) an Appalachian

iuii, along the Appalachians west of the Archaean ranges from Alabama
to ( lanada, the Green Mountain area included : I •"> | an Interior ( Jontinental
basin, between the Appalachian chain and the Rocky Mountain chain ; and
(4) a Western or Pacific Border region, "west of the Rocky Mountain
Summit," as the four great partially distinct areas of continental progress,

My subject at this time is: The areas of continental progress in the light
of existing facts, and the influence of their conditions on the work carried
forward within them.

1. In the firsl place I observe that the boundaries separating the Atlantic
and Pacific borders from the Continental interior should he drawn, as far
as pos.-ihle, along the ranges of Archaean ridges jusl referred to. These
were boundaries al the beginning of Paleozoic time; and they have been
r Bince the more important division-lines for noting progress. On
account of the Archaean origin of these axial lines in the two mountain
chain-, and the fact that in their elevation the existence of the Appalachian

and Rocky Mountain chain- had their beginning, I propose to Call each the

Archaean protaxis of the chain. The Appalachian protaxis extends along
the Green .Mountain region as an interrupted range, and i> continued
through Putnam and Oran ( N < w York, northern New Jersey,

eastern Pennsylvania, and thence southwestward to Georgia, as a series of
ridges, and in some parts nearly parallel ridges, making part of the wide
an a of crystalline rocks.

The protaxis i- not now the highest part of the chain, but it i- the oldest
part ; and although an embryonic feature in the continent, it probably had
om >t throughout, which it has lost by time's long erodings.

(6)

ARCH.EAN PROTAXES OF THE CONTINENT. 37

Much the larger part of later fragmental rocks, limestones excepted, are
made out of what the Archrean ridges have lost.

2. Again, the Archsean ranges east of the Appalachian protaxis and those
west of that of the Rocky Mountain are entitled to like recognition in the
continental history.

To the northeastward, over the New England and Canada extension of the
continent, there are two or more such ranges.

First. An Archoean range of prominent importance crosses — with some
interruptions and approximately parallel ridges as usual — New Brunswick
from the south side of Chaleur Bay, on the Gulf of St. Lawrence, having
outliers in southwestern New Brunswick, passes southwestward to the coast-
region of Maine east of Mt. Desert, and thence continues as a broad belt into
Eastern Massachusetts and perhaps into Eastern Connecticut. It is a
boundary between two Paleozoic regions. On its eastern side it has fossil-
iferous Cambrain and later Paleozoic rocks in New Brunswick and Eastern
Maine, Upper Silurian occurring in Machias, Pembroke, and elsewhere, and
fossiliferous Cambrian in Eastern Massachusetts — all belonging to the west-
ern border of the eastern of the two Paleozoic regions ; and on its western
and northwestern side there is the large Paleozoic basin of Middle and
Northern Maine. And if we follow the western outline of this Archsean
range from Maine into Massachusetts, we find that the Nashua synclinal of
argillite and mica-schist, just west, is probably an extension of the Maine
Paleozoic to Worcester, where anthracite, graphite, and carboniferous plants
occur as evidence of the existence of the coal formation. The lines on Prof.
Edward Hitchcock's Geological Map of Massachusetts, in his quarto report
of 1841, correspond well with this view, and the descriptions of the rocks by
Mr. L. S. Burbauk and Prof. W. 0. Crosby favor it.*

Secondly. A second range of probably Archsean rocks commences in the
northern part of western Newfoundland and is continued southwestward,
with the usual interruptions, along Nova Scotia. This second Archaean
range and the preceding are the confines of the great trough — Bay of Fundy
trough it might be called — in which lie the Carboniferous and other Paleo-
zoic rocks of New Brunswick, Nova Scotia, and western Newfoundland, and
the Triassic rocks of the borders of the Bay of Fundy, of undetermined

* Mr. L. S. Burbank in Prof. W. O. Crosby's "Report on the Geological Map of Massachusetts,"
1876, in which Mr. Burbank's observations are published as a separate paper; also Professor
Crosby in his Geology of Eastern Mssachusetts, Boston Soc. N. H., 1880.

Professor Hitchcock's Map, in his Report of 1841, represents the synclinal of mica-schist as hav-
ing along the center a broad belt of clay slate, and he describes the slate (pages 127, 556, and also
page 55 of his Report of 1835) as becoming a finegrained imperfect mica-schist at Worcester, where
it contains a bed of anthracite a few feet thick. The mica-schist is described as arenaceous and in
some places passing into quartz rock. Amos Eaton, in his Geological Text-book (1832), speaks of
the rock at Worcester as argillite containing "anthracite and impressions of ferns." In Harvard,
to the east of north of Worcester, the area of mica-schist contains aridge of granite, and east of this
ridge, according to Mr. Burbank, a coarse conglomerate occurs, which to the south blends with
the conformable mica-schist. The area of argiilite and mica schist widens northward and bends
northeastward into the Merrimae valley at Lowell. On the east of the synclinal lies the Archaean
area.

J. I>. DANA — AREAS "I CONTINENTAL PROGRESS.

thickness, as well as the Triassic of Prince Edward [aland. To thia trough
the coal formation of Rhode Island and an adjoining part of Massachusetts
with its associated Cambrian may belong — as long sine I; for the

Boundings strongly favor the idea that this Nova Scotia range extends on
beneath the ocean's border, and, as recognized by Prof. W. ( >. < Irosby in bis
1 ■ ology of Eastern Massachusetts, thai it ha- it- continuation, under

iund, in tin- Cape < lod ami Plymouth region of southeastern Massachusetts.

Other approximately parallel Archaean ranges may exist farther eastward
in Newfoundland as boundaries "I' Paleozoic troughs; but the published
facts do doI enable us now to define them.

Thirdly. A third range of probable Archaean extends along New Bamp-
Bhire, on the easl -id.' of the Connecticut valley, through Massachusetts into
Connecticut, dividing the Paleozoic trough of Maine from thai of the Con-
oecticut valley; and this Connecticut valley trough ended it- rock-making
career, like that of the Bay of Fundy, in the laying down of some thousands
of feet of Triassic beds.

Through these Archaean ranges we thus have the confines of three troughs :
The Connecticut valley trough ; that of Maine ami western New Brunswick,
extending southward to or beyond Worcester. Mass.; and the Day of Fundy
trough, covering eastern New Brunswick and western Nova Scotia and New-
foundland, with much of St. Lawreuce Bay, and extending probably far to the
southwestward in or beyond the coal region of eastern Massachusetts and
Rhode [stand. All three opened northward into the great St. Lawrence
Gulf which in early geological time occupied the region of the St. Lawrence

river valley.

It i- UOl to lie inferred that Mich troughs were alike from north to south
in rock-making. The Connecticut valley trough had thick deposits of
Upper Silurian and Devonian rocks laid down in its northern half, which
implies deep subsidence, ami at presenl we have no evidence that Bimilar
depositions took place in the southern half. It had its thick deposits of
Triassic beds in the southern half, which we are quite >m>- did not extend
through the northern half. Hut, notwithstanding Bucb independent work

in the different part-, it was one trough in its Archaean Confines, and in its

relation- to the general Bystem of progn

It thus appears thai Archaean operations first established the boundai
ami that Paleozoic ami Meeozoic rock-making wenl on in the troughs be-
tween these boundary ranges; ami, further, in view of the great thickness of
the rocks, that all tie troughs wen- profoundly, ami re or less independ-
ently, subsiding

'flier.- i- this limitation t" the conclusion, that " Paleozoic rock-making
went forward within the troughs." The earlier pari of this Paleozoic rock-
making, that of the Cambrian and Lower Silurian, went on doI only in tie

DEVELOPMENT OF TTIE EASTERN BORDER REGION. 39

troughs, but overstepped their boundaries. This overstepping was true even
for the Appalachian region, and, consequently, rock-making areas of sub-
sidence were not then so narrowly limited in Eastern North America as they
were afterward. These early Paleozoic formations, the Cambrian and Lower
Silurian, spread from the interior continental seas across the lower parts of
the Archaean protaxis, filling the seas between the Archaean islands and
extending to the Atlantic border south of New York, and probably to the
Connecticut valley on the north.

But after the Lower Silurian era had passed, and also the epoch of disturb-
ance closing the era, this overstepping the boundaries of the troughs in East-
ern North America was, in general, no longer a fact. The Upper Silurian,
Devonian, and Carboniferous rocks never extended over the Green Mount-
ains or beyond the Taconic range, for the region — that is, the Green Mount-
ain area — had, in the mean time, emerged. Moreover, it is not yet known
that these strata spread eastward from the Interior Continental area over
any part of the crystalline rocks of the Atlantic Border region, or, I might
say, over any part of the Atlantic Border region. They may and probably
do exist on the border beneath the Cretaceous and Tertiary, or beneath the
ocean's margin ; but they are not yet known from actual observation to have
extended east of the Archrean protaxis. The Jura-Trias of the Atlantic
border rests in many places on Archaean, Cambrian, or Lower Silurian, but
not as far as yet known on later Paleozoic rocks. According to Prof. G. H.
Cook, of New Jersey, borings through the Cretaceous formation between
New York and Trenton, N. J., reach only crystalline rocks, much re-
sembling those of New York island.

The boundary-range separating the Interior Continental region from the
Atlantic Border region was, hence, greatly widened before the Upper Silurian
began, by the addition to the Arclmean of the Cambrian and Lower Silurian
formations, and their addition to a considerable extent in a crystalline or
metamorphic state. They were added in the metamorphic state in western
New England, where we have Lower Silurian and Cambrian strata in a
crystalline condition combined with the ranges of Archeean — those of the
protaxis — and all together in combination making up the Green Mountain
area as it existed in the period of the Upper Silurian. There is no question
as regards the Taconic system here involved. For the discoveries of fossils
by the Vermont survey, and by Wing, Walcott, and Dwight, have definitely
proved that the Archaean is bordered and combined in the Green Mount-
ain region with Cambrian and Lower Silurian strata ; and, being thus com-
bined, it was emerged before the Upper Silurian era began. The Archaean
protaxis of the Appalachian region was similarly combined with Lower
Silurian ; for uncrystallized Cambrian and Lower Silurian strata are visibly
so associated, and besides this, it is probable that part of the crystalline

10 .1. D. DANA — AREAS "I CONTINENTAL PROGRESS

schists are Lower Silurian, as has I a suggested by several writers on the

region.

&for< >ver, the protaxial area, thus widened, was probably, throughout later
Paleozoic time, an emerged area to the south as well as to the north — that
is, it was above the level of marine waters. Great subsidence took place
over the Triassic areas of the Atlantic Border region — 2,000 to 5,000 feet
at least — but it took place without letting in salt water. They were local
subsiding areas or troughs.

The same widening of Archaean boundary-ranges by an inclusion of Cam-
brian and Lower Silurian areas probably took place, also, in New Bruns-
wick and Nova Scotia.

Fourthly. These facta from Eastern America with regard to the break he-
tween the Lower and Upper Silurian make it apparent, and more so than has
been hitherto recognized, that the close of the Lower Silurian era marks offone
of the grander divisions in American geological tim >, asii does also, though l<
strikingly, in that of Europe. The importance of the epoch in geologi-
cal history is manifest also in Western America; for while evidence of any
disturbance fails, the Upper Silurian is to a large extent absenl or nearly

if we may judge from known facts. Consequently, the boundary lines
of the Lower Silurian areas, not unfrequently omitted, are among the most
importanl of the lines which a geological map of North America, or of the
World, should contain.

1 take this opportunity to add, as a second corollary, that then is good
reason in the importance of the Lower Silurian era— g 1 chronological, geo-
logical, and paleontological reason — why the name Silurian, which the Lower
Silurian has so long held, should be perpetuated to it, and good reason why
the name should not become attached only to the small end of the Silurian
era, the so-called U pper Silurian, which has little in its new type- that is
nol more characteristically Devonian, and which bas do! one-fourth the area
of distribution or thickness of strata in North America that the I. own-
Silurian has. There is reason for this also in what is due to the came of
Murchison, whose labors for his " Siluria " where largely among the Lower
Silurian rocks, and who.-e troubles with Sedgwick cameoul of their separate
labors in Lower Silurian and < lambrian rocks without the intention in either
of encroaching on the other's rights.

The Upper Silurian may conveniently take a new name, hut it is ool
me. ssary to go for it to the aame little land of Wales that has supplied the
two, Cambrian and Silurian, in honor of Sedgwiok ami Murchison. \\ •
may better look elsewhere for the third name. There is the land of Bohemia,
where Barrande worked oul his Silurian and Primordial systems, and tin re
is the area of V-w York and Canada where were laid the foundations of
American Paleozoic geology, and where our honored president, James Mall,
has carried on his paleontological labors.

DEVELOPMENT OF THE INTERIOR CONTINENTAL REGION. 41

The term Bohemian has been already used for the Upper Silurian by the
French geologist, M. de Lapparent, in his Treatise of 1883. The name
Ontarian is suggested by the actual use of the term " Ontario Division " for
the lower portion of the Upper Silurian by Mather, in his New York Geo-
logical Report of 1843, and by Emmons, in his Report of 1846. And it is
in its favor that Upper Silurian rocks prevail over much of Ontario, Canada.

Cambrian, Silurian, Ontarian, would make a satisfactory triplet. What-
ever name shall be adopted for the Upper Silurian, the working ground of
Barrande, or that of Hall, Billings, and others should some way be recog-
nized, and to this even the distinguished author of the term Ordovician
would not, I am sure, enter his dissent.

Fifthly. I come now to the " Interior Continental " region. Three sub-
divisions are suggested by the geology and ancient topography of the region,
which have eminent importance as regards rock-making. The mountain-
making disturbance which followed the close of the Lower Silurian left, as
Newberry has shown for Ohio and Western Indiana and Safford for Ten-
nessee, a region of shallow seas and low emergences along a belt extending
southwestward, parallel nearly with the Appalachian protaxial area, from
the west end of Lake Erie to Southern Tennessee — a region which has been
long called the " Cincinnati uplift." The Canadian geologists find the in-
fluence of the uplift extending farther north, to Lake Huron. The course
of this region of shallow seas and emerged land may be made the first
division line through the Interior Continental sea.

The second I would draw along the western limit of the Paleozoic areas
on the geological map of the country, or, what is the same thing, along the
eastern limit of the Mesozoic, from Western Iowa southward to Texas and
northwestward to the Arctic coast. The Paleozoic area on the east of the
line was at the time, for the most part, the non-subsiding land of the conti-
nent. The Mesozoic area on the west of the line was the immense subsiding
area, for the area had the length of the continent from south to north or
rather northwest, and it continued its sinking through the Triassic, Jurassic,
and Cretaceous periods, or at least, if ceasing for part of the Triassic and
Jurassic, it went on through part or all of the Cretaceous period. What
determined this strong boundary line or limit is not clear; possibly some
underground Archaean feature. And perhaps uplifts at the close of Paleozoic
time help to mark it, if Prof. Robert T. Hill is right in referring the steep
upturning and flexing of the Carboniferous rocks of Western Arkansas and
the adjoining Indian Territory to the close of the Permian period.

These two boundary lines divide the Interior Continental region into three
great sections : (1) The Eastern Interior east of the Cincinnati uplift ; (2)
the Central Interior or Mississippi Basin ; and (3) the Western Interior or
that of the Eastern Rocky Mountain slope. Of the four subdivisions laid

VI— Bull. Geol. Soc. Am., Vol. 1, 1889.

12 J. D. DANA — A.REAS OF CONTINENTAL PROGRESS.

down by me in 1875, the Appalachian area corresponds to the Eastern
Interior. Prof. II. S. Williams, in his communication on the Devonian in
lss7 to the committee of the International Geological Congress, recognized
the t'aet that the term Appalachian and my definition of it gave it too narrow

limits ami used that of Eastern Interior.

The Central Interior might be further divided into an East-Central and
West-Central, along a line commencing in the chief Archaean region of Mis-
souri, an island, or group of islands, in the Paleozoic sea, to the west of which
the Upper Silurian and Devonian strata appear for a long, undetermined
distance to be mostly or wholly wanting.

The title of my paper includes, as its second clause, " the influence of the
conditions of these ana- on the work carried on within them." I will now
illustrate this point by going into some detail with regard to one of these
sections, the Eastern Interior.

The influence of the Cincinnati harrier on subsequent rock-making has
been recognized by Professor Hall, Professor Newberry, and others, but I
think that this influence was much greater than has been appreciated. Note
the position and length of this partial harrier of shallow seas and emerged
lands between the Western and Central Interior, its extension from Lake
Erie, or the southeast side of Lake Huron to Southern Tennessee and some-
what beyond it, and then consider the size of the area enclosed, namely,
parts of Mississippi, Alabama, and Eastern Tennessee, Eastern Kentucky,
West Virginia, Eastern Ohio, nearly all of Pennsylvania, ami all of New
York, excepl it- northern portion, the length not less than TOO miles. Note
also that the great subsiding Appalachian trough, or group of troughs, ex-
tended over a broad eastern portion of the area, ami that the subsidence
involved to some extent the whole.

Now, when the Upper Silurian era opened, the region of Albany in
Eastern New York was near the head of a great Northeast Bay in this
Eastern Interior Sea. It was essentially a hay ; for the old sea-channel of
the Lower Silurian era, extending over the Lake Champlain region to
Canada, in which the Lower Silurian formations had in succession been laid
down, was closed by the beginning of the Upper Silurian, :i- the records of
the Niagara period show, or, at [east, so far closed as to he no longei a con-
tributor toward rock-m iking, and it e mtinued to be thus far closed except
during the Lower Helderberg period, through the resl of Paleozoic tim<

* The closing of the i I nol have 1 lete through all this time as to have ex-

ejudi termigration ■ i- probable thai the chief open paw i ird !"■

Ivsnia where the Arch
protaxii has i minimum height The waters over tnis wide connecting

kve left vi l.'M s of the Upper Silurian, Deronl

. in 1 1 i in- they would nol )"• likely to •!" unless 1 1 • • - region
eg) •!> of i would I i . Vfiy thin and easily

washed awav.

MIDDLE PALEOZOIC SEDIMENTATION. 43

This Northeast Bay must have received the embryo Hudson, a stream then
of little length but of abundant Adirondack waters ; and also such other
streams as the slopes and rains could produce; but no salt-water currents nor
tides bearing sand and gravel from Canada and the Atlantic borders on the
northeast. Aud even in the Lower Helderberg period, when it is supposed
(first by Logan) that the broad Champlain Lake region was again under
salt-water, there were no contributions of coarse sediment from the Canada
and Labrador region, although there must have been of living species, for
the Lower Helderberg rocks over the region are limestones, and mostly
argillaceous limestones. An opportunity for such fragmental contributions
by these Champlain Straits may have existed in the epoch of the Cauda
Galli grit, at the commencement of the Devonian, as suggested by the
presence of its beds, according to Prof. Wm. M. Davis, over the lower
Helderberg in Becraft's Mountain, east of the Hudson river ; but this is
not probable.

I would add that the closing of the Lake Champlain area against the sea
cotemporaneously with the emergence of the Green Mountains, and its con-
tinuing to be essentially closed, signifies that the region of the Appalachian
subsidence no longer embraced the Green Mountain and Lake Champlain
area, although it continued to extend over much of the eastern half of New
York, as we learn from the many thousand of feet in thickness of the later
Upper Silurian and Devonian formations.

Observe here what a blow the fact of this closed Northeast Bay gives the
old theory — which I have held as well as others — that the coarse and fine
sediment for Appalachian rock-making, during the Upper Silurian era and
afterwards, came in, period after period, from the northeast, through Labra-
dor currents. The facts from the distribution of New York and Canadian
Devonian and Carboniferous rocks bring us to the unavoidable conclusion
that all the sedimentary beds of New York and the Alleganies, through the
Upper Silurian, Devonian, and Carboniferous eras, though so many thou-
sands of feet thick, were made within the Interior sea out of material derived,
so far as non-calcareous, from the wear of rocks about it, and that the tidal
and other currents of the Interior sea distributed the material.

This Eastern Interior sea, while closed in the direction of Albany, had,
during tbe Niagara period of the Upper Silurian, a wide open way westward
over Ontario, Michigan, and Northern Ohio ; and here the tides entered as
freely as from the southwest. But afterwards, in the Salina and Lower
Helderberg periods, it became much less free, though still open, for the
Cincinnati barrier made transitions in these Interior regions easy from an
open clear sea to great areas of salt-pans over west-central New York, and
still wider regions of salt-water and brackish-water flats, such as the deposi-
tions of the Salina and the Water-lime beds prove to have existed. The salt

11 J. D. DANA — A.REAS OF CONTINENTAL PROGRESS.

pan region referred to was nearly 200 miles in length from east to west, and
that of the shallow Bea-flata of the Water-lime over three times this length.

The western passage way, or that over Michigan and Northern Ohio, was
again deep and widely open through most of the Corniferoua period. After-
ward there was again a narrowing and a shallowing. It is' easy, with the
geological reports of the State of New York and those of the other States
along the Eastern Interior region, to follow out the various changes that
came over the area and its western open way, and also the coming on of the
area of alternating emergences and submergences characterizing the coal
period. I have been over the records, but have to confine myself here to a
few prominent point.-.

The conditions of such a bay during the Upper Silurian, Devonian, and
( arboniferous eras would have influenced tide-, currents, temperature and
parity of waters, sediments, life, and everything that could have affected
rock-making and biological distribution. The conditions were varied, also,_
by oscillations in the water-level, and here and there by the throwing up of
long beach-made or sand-flat barriers. In either way, great shallow confined
seas, like Pamlico Sound and others of the Atlantic border, but perhaps
larger, mighl at times have existed, especially as the waters became more
shallow ; and such seas would have been likely to vary from purely marine
to intensely briny, on one side, and to brackish and fresh on the other.

These few particulars are enough to make it manifest that the consequences
of the geographical conditions in the Eastern Interior sea must have been of
most comprehensive range.

As regards life, the head of the Eastern Interior region, comprising the
area of New York and Pennsylvania, would have been the least favorable
of the whole Interior Continental sea for pure-water species. Whenever
depth and purity of water favored, such sp vies would have gone in ami
flourished and made limestone, as they did during much of the Niagara and
< ' irniferous periods. But, in general, pure-water species would have been,
and were, absent. The species outside would have migrated in or not accord-
in.: to their habits, and readily, for where there are tides and currents migra-
tion of marine species is rapid work. lint under BUch circumstances the
stratigraphical succession could nit correspond to tie- true biological sue
sion of species. It would be only local-condition succession. Prof Henry

9 William- established this conclusion fully by the facts from the Devonian

of New York which he presented to the A.merican Association in bis very
valuable paper of 188 i, and Prof. < '. L. Herrick has recently drawn atten-
tion to similar facts and presented explanations of similar import/] They

►H.8. Wl i •- ,,( iii.' Inter, \

IN in nan, ibid. 1884, i

■ ' • l- Herrick, iIob 'in... Hull.- i i I r, Vol. IV, p. 97, In a

niiriu.'l from Voli, II nil.) III Mr Hen ries ..i "

logical :i|.li..n-.in-,' on pag •• ili.' prlnci] ted.

EFFECT OF CONDITIONS OF SEDIMENTATION. 45

may well lead geologists all over the world to consider the question : How
large a part of the stratigraphic succession of life, which is made so much of
by the careful noting of zones, is only local-condition succession ? Walcott's
discovery, in the Eureka Devonian beds, that many species of the New
York, Hamilton, and a few Chemung species occur in the Lower Devonian
of Eureka and some Lower Devonian of New York in the Upper of Eureka*
give emphasis to the reasons for careful and comprehensive study before con-
clusions as to biological succession are endorsed " established."

I might illustrate also the influence of the varying conditions, in such a
Northeast Bay, on rock-making, but add only a single thought. In the
matter of the tides, how exceedingly varied are the circumstances that
would have attended deposition in consequence of the changing positions and
force of the tidal currents which variations in depth and other causes would
have occasioned ! Conglomerates would have been formed where the cur-
rents were strongest. But, in the same long geological epoch, the strongest
tidal current out of the great Northeast Bay might have had many different
positions over western New York or Pennsylvania or over eastern Ohio,
and thus conglomerates would have been made at various levels, which the
geologist might, unless cautious, take as equivalents.

The Central Interior and Western Interior regions I pass without special
remark, although they derive great interest from study parallel with that of
the Eastern Interior.

The Pacific Border region owes its maximum width, which occurs in the
United States portion, to the east and west bend of the Archaean protaxis of
the Rocky Mountains in Wyoming and Southern Montana. This Archaean
bend carries eastward, in a somewhat irregular way and more than 250 miles,
the part of the protaxis south of the bend.

Over the Pacific border, there are, as has been recognized, two prominent
lines or series of mountain ranges nearly parallel with the coast: (1) The
Coast chain, which includes the Coast ranges south of Vancouver's Island,
and the island ranges along the coast northward ; (2) The Cascade chain,
as it may be called, including the Sierra Nevada, the Cascade range of Ore-
gon and Washington Territory, and ranges of mountains in British America
that are nearly in the same line. Neither chain has a well-defined Archaean
axis except for a small part of its course, and this is probably owing to the

*C. D. Walcott, Paleontology of the Eureka District, 298 pp., 4to., with 24 plates of fossils, 1884, U.
S. Geological Survey. The lower part of the Eureka Devonian limestone contains many Upper
Heiderberg species'of New York and other States east o( the Rocky Mountains. But with these are
manv that are Middle and Upper Devonian in New York and elsewhere; among these, the three
Hamilton Tentaeulites, T. attenuates, T. bellulus, and T. graeilistriatus. Besides this, some New
York Upper Heiderberg species are found in the upper part of the 6000 feet of Devonian limestone,
as Cladopora proliftca Hall, Chonetes mucronata Hall, Euomphalus laxus Hall ( Upper Heiderberg and
Hamilton in New' York). Again, many of the species of the lower part occur also in the upper,
showing long survival of individual forms— e. g.,Streptorhynchus chemungensis, 4 species of Productus,
Chonetes defiecta, Strophodonta perplana, 2 species of Spirifera, a Paracyclas, Styliokt ftssurella,
Rhynchonella castanea Meek (a Mackenzie river species). Many of the species are represented in
the Devonian of Iowa, or the Continental Interior, where the waters were purer and probably deeper
than in the New York Bay, and therefore more like those of the Eureka District.

16 J. D. DANA — AREAS OF CONTINENTAL PROGRESS.

thickness of the later sedimentary formations and the igneous outflows.
The Cascade chain, however, has an axis of granitoid and other crystalline
rocks for the most of tin- Sierra Nevada portion, which is probably Archaean
in time of origiu ; and the Archaean range is a long one, it' it extends, as is
reasonably urged by Mr. W. Lindgren, through the length of Lower Cali-
fornia.

The intervening depressions, in the Pacific Border region, are first, the
Great Valley region, between the (.'oast and the Cascade chains, com-
prising the valleys of the Joaquim and Sacramento in California, the Will-
amette in Oregon, and valley-like depression between the so-called Coasl
Ranges of British America; secondly, the GREAT Basin region, whose
eastern boundary is the Archaean protaxis in British Columbia, but in the
United States, south of Montana, is a north and south line through the
Great Salt Lake, as shown by King; thirdly, owing to the bend of the
Archaean protaxis, widening so greatly the Pacific Border region, the United
States, south of Montana, has a Rocky-Summit region, which is the third in
the Beries of regions counting from the coast, while "Washington and British
Columbia have but two.

The eastern limit of the Great Basin region, distinguished by King, divid-
ing it from the Rocky Summit region, is very nearly coincident with a south-
ward extension of the northern pari of the Archaean protaxis, or that north
<>f the bend ; and probably a series of Archaean ridges once continued along
this line, of which we have remains in the outcrops in and near Salt Lake,
including the high Archaean range along die Wahsatch Mountains, and in
other ridges farther south. Whether a continous range ever existed as a
western boundary or not, the" liocky Summit " region appears to be confined to
the United States, and to have well-defined limits— the western line extending
by Salt Like weal of south to the crossing of 1 1 1 ■ - parallel of 37 and the
meridian of 1 15 W., and then bending southeastward to the borders of Texas
and Mexico. West of the line for a long distance over the Great-Basin as
Kim:'- Report .-hows, the ( 'arboniferous rocks are the Latest ; directly easl of
it at many points begin the Cretaceous; and thus the distribution of the

ii areas of Cretaceous on a map makes it generally easy to trace the
boundary, in spite of the great loss from erosion.

Hut so far as the northern boundary is concerned the" well defined limits"

made by the Archaean have, geologically, only a superficial value. The

on i- actually continued, stratigraphically and orographically, into the

bigh Rocky Mountain summit bell of British America, although thi- belt i-

wholly east of the Archaean protaxis.

The identity between the two regions, north and the other south of

the Archaean bend, is apparent in several of their characteristics B >th are
on- of Paleozoic and Mesozoic rocks, in which the Cambrian, Carbonif-

DEFORMATION IN THE PACIFIC BORDER REGION. 47

erous and Cretaceous formations (the Laramie included) make the chief
part. Both are regions of great mountain-making displacements of post-
Cretaceous occurrence. Both are the courses of high and bold mountains
dependent for their origin on these displacements.

But there is a contrast in the extent and results of the displacements.
South of the Archaean bend, the mountain-system is in part that well called
the Plateau system by Major Powell ; north of the bend, in British
America, it is the Appalachian system, according to the results of the geolo-
gists of the Canadian survey, Dr. G. M. Dawson, and more definitely Mr.
R. G. McConnell. Mr. McConnell, in his report of 1886 on the region
about the pass through " the Rocky Mountains " of the Canadian Pacific
Railway, describes and figures ordinary and overthrust flexures, and
upthrust faults of 1,000 to 15,000 feet, precisely, says Mr. McConnell, like
those " in the Appalachian region of East Tennessee, described by Prof. Saf-
ford " ; and in one section, which he figures, there is a vertical displacement
of 15,000 feet, and also a shoving of Carboniferous limestone almost horizon-
tally over Cretaceous beds to the eastward for " a distance of nearly two
miles." From the observations, the whole amount of horizontal displace-
ment in this fault was estimated by Mr. McConnell to be seven miles. The
resemblance to the Appalachian system includes the fact that the upthrusts
and overthrusts were, in each observed case, landward in direction. Dr.
Dawson's facts from the region south, nearer the 49th parellel, published also
in the Canadian Geological Report for 1886, are similar as to the character
of the flexures and faults except that some of the faults appear to be up-
thrusts westward. Mr. J. B. Tyrrell has obtained supplementary facts from
northern Alberta. Further, the report of Mr. O. H. St. John, in the Hayden
volume for 1877, contains a plate of sections across the Wyoming mountains
in western Wyoming, south of the Archaean bend, representing flexures
and faults like those described by Mr. McConnell.

I have not, myself, studied the region with reference to the transitions ;
but in view of the facts that the mountain-making to the north and south
involved the same rocks to the top of the Laramie, and that these rocks were
involved, therefore, in the same great subsidence attending the thickening of
the accumulation of the Mesozoic beds as well as those beneath, I think we
can hardly doubt that all is one in general system, orographically not less
than stratigraphically, although successive portions of the summit belt may
have had a degree of independence in the movements.

We learn from the facts, as we have also from those of Lower Silurian
history, that an Archaean protaxis is not necessarily a fast boundary with
regard to geological work. The Cretaceous seas spread among the Archaean
heights, and in the region south of Montana for a long distance beyond them,

18 .1. D. DANA — A.REAS OF CONTINENTAL PROGRESS.

and, nevertheless, the orographic movements affected more or less the whole
belt.

The later areas of rock-making, those of the Eocene Tertiary, which also
wen areas of profound subsidence, were bounded by the mountains which
had just before been made and put into combination with the Archaean
ranges.

Ajb to rock-making within the Great Valley and the Great Basin regions,
and the relations of the various local subsiding troughs in the latter, more
facts are needed for any general conclusions.

Prom this review of the system of progress in a case of continent-making
we learn that the areas of rock-making were defined for the most part in
Archaean time : that their confines were old Archaean ranges, or else later
uplifts made in accordance with the Archaean system ; that <m the Atlantic
border the Cambrian and Lower Silurian formations were united to the
Archaean so as to widen the Archaean or protaxial boundary range : and we
have reason to conclude also that areas were rock-making bo far and so lone
as they were subsiding troughs.

It is also seen that the larger part of the work of marine waters was done
within interior continental seas without contributions of rock-material from
outside or aid from the ocean's waves or currents, either those of the Atlantic
or Pacific, for the most part, therefore, the growth of the continent, so far
a- througb marine waters, may he said to have been endogenous. It began

to he exogenous on the Atlantic Bide in tin Creta< us era, these beds there,

and tin' Tertiary also, being of sea-border origin; yet vastly the larger part
of the Cretaceous rocks of the continent, although marine, were made in
interior seas.

>n the far east Paleozoic and Mesozoic area, including much of Nova
5 >tia and Eastern New Brunswick, had its outside Archaean boundary, and
was a trough of Archaean confines, not the margin of the open Bea. The
open Bea is a harsh region for rock-making, and only limestone-making
through coral growths and the associated life appears to succeed well in the
face of the heavy breakers.

It is of the highest interest t" find, in such a review of events marking off
tin- growth of tin- continent, that the grander lineaments were well defined,
and the grander movements initiated, in \i< early headlining. Surely, there
can In- no mistake in tic conclusion that tin' continent ha- ever been a unit
in its system and law- of development ; or the wider conclusion that all the
continents " have had their law- of gr »wth involving consequent features, as
much a- organic structures." *

STUDY OF A LINE OF DISPLACEMENT IN THE GRAND
CANON OF THE COLORADO, IN NORTHERN ARIZONA.

BY CHARLES D. WALCOTT, OF THE U. S. GEOLOGICAL SURVEY.
Read before the Society, August 29, 1889.

CONTENTS. Page

Introduction 49

The Fault and the Periods of Faulting 51

Description of the Butte Fault 51

The Pre-Cambrian Movement 56

The Tertiary Movement 57

The Flexing of Strata on the line of the Fault 57

The Butte Fault and the Grand Canon 60

Analogy between the Hurricane Fault and the Butte Fault 62

Paleozoic Movement 63

Kesume 64

Introduction.

During the summer and fall of 1882 I was engaged in studying the
Paleozoic rocks of southern Utah and northern Arizona, north of the Grand
Canon of the Colorado river, and iu the winter of 1882-83 in a detailed
study of the geology of a portion of the Grand Canon. The area under
investigation in the Canon included its head, at the foot of Marble canon,
and the Grand Canon with its lateral canon valleys on the west, from Nun-
ko-weap valley outlet to the westward turn of the canon, where it cuts
through the Kaibab plateau aud exposes the Archean rocks in the depths
of the inner canon. A partial account of the notable sections of Algonkian
and Paleozoic strata has been published,* but nothing has yet appeared re-
lating to a line of displacement whose early history was mainly determined
by the study of the stratigraphy within the canon. To-day I wish to describe
this displacement and also to call your attention to certain conclusions drawn
from the consideration of the phenomena presented by it.

- *Am. Jour. Sci.,3d ser., vol. 26, 1883, pp. 437, 442, 484. Bull. U. S. Geol. Survey, No. 30, 1886, In-
troduction.

VII— Bull. Geol. Soc. Am., Vol. 1, 1889.

(49)

."<» C. D. WALCOTT — A DISPLACEMENT IN THE GRAND CANON.

The displacement lias long been known as the East Kaihab fold of Po\vell.;;:
Captain Dutton describes it as the longest line of displacement known to
him: " Its total length, reckoning as one displacement the Wasatch, Grass
Valley, Table Cliff, ami Eastern Kaibab portions, cannot fall much short -of

300 miles, and may considerably exceed that after the termini have been
discovered. It presents many phases or modifications, but the dominant
feature is the monoclinal form. The maximum displacement is at the
Wasatch Plateau, and reaches nearly 7,000 feet."f The Eastern Kaibab

porti f this gnat displacement will be considered apart from the more

northern divisions. It extends as a monoclinal fold, with the down curve
to the east, from the foot of the Vermilion cliffs, in southern Utah, along the
eastern side of the Kaibab plateau to the precipitous northern walls of
Nun-ko-wcap valley, in the Grand Canon. Here the fold abruptly changes
to a fault that extends to the southeastern walls of the canon, where it again
merges into the fold and disappears.

Butte Fault was the name which I selected and applied in my field notes
on account of its connection with the origin and development of the six
great buttes in the northeastern portion of the Grand Canon. These buttes
rise from 2,000 to 3,000 feet above the Colorado river and extend along its
western side, from the narrow canon outlet of Nun-ko-wcap valley to the
foot of dinar valley, a l'r\\ miles south of the mouth of the Little Colorado
river. Not only the buttes, hut the canon valleys of Nun-ko-weap, Kwa-
guut and Chuar, and the visible line of the fault, are situated entirely within
the greal ampitheatre enclosed by the canon walls to the southwesl and west
of the head of the Grand Canon.

In order to clearly indicate the stratigraphic position and thickness of the
Btrata affected by the east Kaihab fold and the Butte fault, the following
table i- inserted :

, Feet.

'I', rtiary 816

8,096

Jurassic (identified) 960

Jura-Trias - 8,480

("Permian 864 ~|

,, , i pper Aubrey Limestone 806 , ,,.,.

( arbomferoue , " ^ i . i tu- r l.lui,

Lower idstone 1,485 (

Red Wall Limestone 962 J

Devonian..... Temple Butte Limestone M

, • I 'I alcareous and arenaceous shales) 1 , ,.-,.

( ambnan — < > l ,060

i sandstone) . /

( Ihuar shales and limestones | ._____. ■">. 120

,. .. I Grand Cafion (sandstones, with lava flows in

,nkian upper part) . .

Yi-iinu (beaded quartzite and schists) ... 1,0

26,600

of the v,. .. i|, High Plateaus of Utah, 1880, <

The Fault and the Periods of Faulting.

Description of the Butte Fault. — On the north, near the foot of the high
walls in the lower end of Nun-ko-weap valley,* a hill formed of several flows
of greenstone, contemporaneous with the deposition of the sandstone inter-
bedded with the flows, is capped by a rough, massive, maguesian limestone
(fig. 1). The pre-Cambrian Chuar strata dip away from it on the north and
west, aud an east and west section shows that the hill is a mass of strata dis-
placed, in relation to the beds on the west of it, nearly 2,500 feet, the fault-
line c (also e of figure 2) separating them sloping to the west with the
down-throw. The eastern side of the hill is cut by two faults, a and b of fig.
1. The western fault c is sub-parallel to b, and brings to view the strata
that underlie the lava beds of the main portion of the hill. The eastern
(Tertiary) fault a has dropped the Chuar and Grand Canon rocks on the
east out of sight and brought the Cambrian Tonto sandstone down so as to
form the eastern base of the hill. The sandstone beds are vertical, owing to
the drag on the eastern side of the fault.

West.

East

Figure 1.— East and West Section at the loiver end of Nun-ko-weap Valley on the North side of the

Brook.

R. W. = Red Wall limestone (Carboniferous) ; U. T. = Upper Tonto (Upper Cambrian); T.
Sd.= Tonto sandstones (Middle Cambrian?); C=Shales of the Chuar group (Algonkian) ; G. C. =
Shaly sandstones of the Grand Canon group (Algonkian) that belong below the lava beds L; a, a
= Butte fault ; 6, b and c, c = Pre-Cambrian faults. Vertical scale, 1000 feet = 1 inch.

West.

East.

T. Sd

C. (c) li. (b) G.C.

Figure 2.— Section on the North side of Nun-ko-weap Valley.

The lettering is the same as in fig. 1. The faults c and 6 are here seen only at the surface, but
their connection with c and b of section 1 can be readily traced. The 700 feet of the Tonto group
above the sandstone and the Carboniferous Red Wall and Aubrey groups are not represented in
the drawn section, although occurring above the Tonto sandstone where the section was taken.

* Nun-ko-weap valley heads as a canon on the east face of the Kaibab plateau, then widens out to
a mile in breadth before contracting to its canon outlet leading into the channel of the Colorado
river. Its entire length is three miles. See maps accompanying Button's Tertiary History of the
Grand Canon, 1882. ._,.

(ol)

52 C. D. WALCOTT — A DISPLACEMENT IN" THE GRAND CANON.

In section 2 (fig. 2), which w;i> taken "><)(• yards north of section 1 (fig. 1),
at the north wall <>4' the valley, the Cambrian Tonto Bandstone and the
superjacent Cambrian limestone arch over the Hue of the Butte fault with-

Vw st

East

^ 05 O.C. (a) U.T. R.W

Fir.uRF. 3.— An East and West Section on the & : ' V ip Brook.

Tlie section faces north fit a point opposite section 1 and south of the outcrop of lava besides the
brook. L.A. = Lower Aubrey sandstone. Other letters and scale as in section 1.

out breaking, and the fault is limited to the pre-Cambrian movement that
displaced the Chuar and Grand Canon terranes of the Algonkian. The
latter movement is shown by the faults b and c, fig. 2. Whether a pre-
( iambrian fault existed on the line of the fault a, fig. 1, is unknown, as the
debris covers the slope at the corresponding point in fig. 2.

West

Pious '• arguni

The rise on the « '" \ Upper Aubrey limestone ; L \

an dn tone; R vv. Red Wall limes) me ' i Upper Tonto shaly lime

. ['onto sandsto • I Chuar group shales; a, a Butte. fault Scale as in fig. 1.

DESCRIPTION OF THE KWA-GUNT SECTION.

The throw of the Tertiary fault (a, a'), in section 1, is about 500 feet, and
in section 3, taken one mile south, over 1,000 feet. One of the pre-Carabrian
faults (section 3) has here disappeared ; the other, probably b, or it may be
b and c of section 1 united, has displaced a fragment of the Grand Canon
group more than 3,000 feet in relation to the Chuar group (see fig. 3).

In the next cross-section (fig. 4), taken on the divide between Nun-ko-
weap and Kwa-gunt valleys, all the faults of sections 1, 2 and 3 are united,
the pre-Cambrian and Tertiary movement having taken place on the same
line of displacement. The upturning of the strata towards the fault is
greatly increased, even to the reversing of the dip of the massive Red Wall
limestone to 30° W. ; and the throw of the fault to the eastward by the Ter-
tiary movement is doubled. Owing to the upward curvature of the strata
in the immediate vicinity of the fault, the displacement on the line of fault
is not more than 500 feet ; but measured a short distance back, where the
actual displacement is shown by the position of the horizontal beds, the
throw is from 2,000 to 2,200 feet. To this must be added the curvature of
the monoclinal fold that occurred prior to the actual faulting. This, on the
line of Kwa-gunt and Chuar valleys, varies from 500 to 700 feet, giving a
total displacement between the strata on the east side of the Colorado river
and on the summit of the Kaibab Plateau, of fully 2,700 feet, on a line
crossing the strike of the East Kaibab displacement. This condition of the

West.

R/W.

C (a) U. T.

Figure 5. — Section on the Divide South of the Kwa-gunt Valley.

The section includes the west side of the Butte and also a portion of the divide on the ridge on
the north side of Chuar valley. The lettering and scale are the same as in section 4.

.", 1 c. i». WALCOTT — A DISPLACEMENT IN" THE GRAND CANON.

fiui It continues several miles, the strata <>n the thrown Bide sometimes ap-
proaching the fault almosl horizontally, but usually bending somewhat
abruptly upward. They often stand vertically, and arc bo metamorphosed,
flattened out, or compressed, that little of the original appearance of the
ruck remains.

Figure 5 represents a cross-section of the ridge south of Kwa-gunt valley,
and figure 6 is a cross-section of the divide Leading into (dinar valley on the
north. The massive Tonto (Cambrian) Bandstone curves gently down
toward- the fault, while the unconformable Chuar (Algonkian) beds beneath

W< st.

East.

H.W.

C. (a) U . T .

FiauBS 6.— Section on ti Ihoftht Chuat Valley.

Thifi section Is of the same type as section 6. The lettering and scale are as in section l

Piovei l.—Ba I and H K\oa*guni Valley.

The ' boar ih nd the ihaly Tonto llrni are vertical or Inclined a little to the

nee. The layri tliy curve back each way from the faull ata, h^ shown in
I m, Vertical scale, -<*> feel 1 Inch.

BRANCHING OF THE FAULT.

and the strata on the east of the fault are flexed up on each side towards it ;
the Chuar strata were turned up in the downward throw, to the west, in
pre-Cambrian times, and the Tonto, Red Wall and Aubrey rocks by the
eastern throw in the movement producing the East Kaibab displacement.
In several localities this has resulted in bringing the soft calcareous and
argillaceous shales of the Chuar and Tonto groups side by side (fig. 7),
and, as both are nearly vertical, no line of demarkation is observable al-
though in the interval between the deposition of the argillaceous shales of
the Chuar group and the bringing of the shaly calciferous beds of the Tonto
into their present relations to them, upwards of 16,000 feet of sediments
were deposited in the Colorado basin, and the geologic history of the greater
portion of the North American continent was written.

The general direction of the fault has thus far been to the south-southeast.
Midway between the Kwa-gunt and Chuar valleys it curves more to the
southeast and then to the south, scarcely deviating from a north and south
line until it reaches Chuar lava hill, where it forks. The east branch passes
north of the hill. It crosses the Colorado river in a southeasterly course and
runs out a short distance up a side canon. Here the upper Tonto and Red
Wall terranes arch over it in an unbroken monoclinal fold although, but a
short distance away to the northwest, the massive Tonto sandstone is dis-
placed by a downthrow of 400, feet to the northeast. The west branch of
the fault continues south a mile or more and then bends to the southeast,
crosses the river and disappears beneath the Tonto terrane, displacing the
Grand Canon and Chuar groups, but scarcely breaking the Tonto beds.
The Tertiary movement appears to have followed the east branch ; this is
shown by a cross-section of Chuar lava hill that cuts across the two branches

West

East.

F.T.

Figure 8. — E. N. E. and W. S. W. Section through Chuar Lava Hill.

T. Sd.=Lower massive Tonto sandstone; C.=Chuar shales; G. C.=Grand Canon shaly sand-
stones. The dip of the latter is the same as that of the lava beds (L) and the Tonto sandstone.
a, a=East branch of fault ; P. T.=West branch, and pre-Tonto fault. The western fault cuts through
the lava bed and separates the western portion which is part of the highest lava bed brought down
by the westward throw of the fault. The fault at this point is not shown in the figure.

of the fault (see fig. 8). One mile south of this section, on the west
branch, the Tonto sandstone is not displaced by the fault, although the pre-
Tonto throw, to the west of the strata of the Grand Canon group, is from

D. WALCOTT — A DISPLAt EMENT IN THE GRAND < \\"\.

1,200 to 1,500 feet Upon this data the restored outline of the pre-Tonto
position of the strata, prior to the Tertiary displacement :it the crossing of
tion v. is given in section 9. The west branch of the limit is inclined :)(>'

West.

East.

T.Sd.

/,. .i-.. - -— r

■■I-"- '"I-

G.C.

P.T.

Figubi '.'. — A Restoration of Section 8.

ting the block forming Chuar lava hill before the Tertiary faulting and erosion of Chuar
valley and the Grand ' iafion. The lettering i* the same aa in ~<-<-t i. .ti g.

from the vertical to the west, and the cast branch is nearly vertical : a fact
that serves to explain the Tertiary movement following the latter, as it was
mainly a vertical displacement.

'/'//< pre- Cambrian Movement. — The westward throw of the pre-Cambrian
AJgonkian) fault, varied at differenl points from tOO to 4,000 feet, owing to
its traversing strata that dip both with and against its strike. All along its
line, except in Nun-ko-weap and Chuar valley- and across the Colorado
opposite Clinar valley, the strata on the eastern Bide are now concealed by
the carrying down of t he Tonto and superjacent rocks by the Ten iary move-
ment. In sections 1 . '_', -s, and 9 the pre-Tonto strata an' shown on each side
of the fault, and on the east Bide of Chuar valley the beds of the Chuar
group are -'en lying up against the west side of the lava hills, mi the line of
the oblique western branch of the fault I fig. s i. To the Bouth the fault pa-- -
through a -addle eroded through the Tonto sand-tone between the hill south

of Chuar lava hill and the main ridge. This proves that the fault crossing

the saddle, with a throw of from 1,200 i" 1,500 feet, is of pre-Cambrian
, as the line nf the Tonto sandstone ha- been scarcely more than
broken by the slight reverei movement that occurred during Tertiary time
on the main fault and it- eastern branch. In every instance where strata of
the (huar group approach the fault the beds are flexed up toward- it on a
tad Bcale, ;i- shown in Bectione I. •». ii. 7, ami 8. Bach from the displace-
ment this flexure disappears by the decrease of dip, as shown in section i,
when- the beds are horizontal one half mile hack of the fault, or in Bection
6, w her. a synclinal in tonne! l. The general dip of the pre-Tonto beds is to
tie northeast. South of (huar valley, beyond where the faull disappears,
tin- strike of the strata i- regularly to the northwest and southeast.

A - determined from the section of the pre-t iambrian fault exposed to ex-

PRE-CAMBRIAN AND TERTIARY MOVEMENTS. 57

animation, its maximum throw was on the line of the greatest displacement
by faulting during the Tertiary movement. It broke into branches and
diminished in throw towards each end of the present Butte fault. This is
not unexpected, as the Tertiary break was undoubtedly over and along the
line of the least resistance below. It roughly duplicated the old line of
faulting, only reversing the direction of the movement about 2,000 feet along
the greater part of the fault. That the rocks of the Chuar terrane are still
displaced from 400 to 2,000 feet, in relation to well-marked Algonkian strata,
proves the profound character of the pre-Tonto fault. The movement pro-
bably occurred during the progress of the elevation of the Keweenawan
continent, and when the Archean (?) and the 12,000 feet of Algonkian strata
now unconformably underlying the Cambrian Tonto sandstone, were brought
to the surface; the agents of erosion planed off the raised and faulted strata,
and not until the remainder of the Paleozoic series, the Mesozoic, and much
of the Tertiary were deposited, did any known movement occur on the line
of the fault, except to form a slight monoclinal fold at or near the close of
the deposition of the sediments of the Paleozoic. (See figs. 11 and 12.)

The Tertiary Movement. — This has been largely described in giving the
details of the various sections, more especially those of section 4, where it is
stated that the eastward throw of the combined fold and fault is fully 2,700
feet. That the latter movement took place in Tertiary time has been well
established by Capt. C. E. Dutton, in his study of the High Plateaus and
the Tertiary History of the Grand Canon. In the following description of
the flexing or upturning of the strata on the line of the fault, many descrip-
tive details will be found that otherwise would be referred to under this
heading.

Flexing of Strata on the Line of the Fault. — The area of pre-Cambrian
strata exposed to view by erosion is limited, but from it we learn something
of the general geologic structure of the pre-Cambrian surface and the con-
ditions under which the flexing of the strata occurred in the vicinity of the
Butte fault.

Eight miles southwest of the southern branches of the fault, the Archean (?)
or older Algonkian rocks appear. Here the plane of their upper surface,
over which the strata of the Grand Canon group were deposited conforma-
bly* and probably horizontally, strikes N. 35° W. and dips 10° to the K E.
The strata above partake of this strike and dip, and, with the exception of
a broad undulation four miles to the northeast that forms a synclinal and
anticlinal. This continues up to the vicinity of the fault. Continuing north-
west of the immediate proximity to the fault, the general strike is west and
northwest with a dip to the north and northeast, as far as the summit of the
pre-Tonto groups at Nun-ko-weap butte, on the divide between Nun-ko-weap

" * Not conformably to the strata of the Areheau (?), as the greatest unconformity prevails in this
respect.

VIII— Bull. Geol.'Soc. Am., Vol. 1, 1889.

D. WALCOTT — A DISPLACEMENT IN THE GRAND CANON.

ami Cwa-gunt valleys. Two Bynclinal folds with a north and south trend,
have been crossed and the Bynclinal in which Nun-ko-weap butte res
has been entered. North of the latter 1 1 1 « - Btrata dip east and south to the
limit of observation at the northern wall of Nun-ko-weap valley.

From Chuar lava hill, in Chuar valley, north to Nun-ko-weap valley, the
pre-Tonto strata rise towards the fault on the west, sometimes to a limited
ree, as in Bection s. though more frequently the flexing embraces one or two
thousand feel of Btrata thai rise, with a more or less abrupt curvature, from
a point half a mile or more west of the fault -< < sections 1. 5 and 6), At
the western fault of Bection 1. in Nun-ko-weap valley, the argillaceous shales
real against the hard lava-, sandstones and magnesian limestones, ami bear
no evidences of metamorphism. In Chuar valley the same thing occurs on
the west side of the west branch of the fault ; hut the strata on the east

side nf the fault, forming the west bIoj f Chuar lava hill (section 8, 1'.

T. fault i and the strata on the west side of the east branch of the fault
sections 8 and '.• I are extensively altered. The lava Hows of the
-tern Blope of the hill, with their interbedded and overlying Band-
ies, are turned downwards towards the fault. The sandstone is changed
to quartzite; the lava is compressed, and so interbedded with the .-ami-
ne that the first impression is that a plastic mass ha- hem pn-sed
against, and dragged down, the slope. On the east fault, massive layers of
sandstone have- been altered to quartzite, and the lava beds curved up as
readily a- the more flexible interbedded sandy -hale-. The Btrata against
which the metamorphosed beds were pressed, at the time of their metam-
orphism, are now concealed by the throw of the fault. Between ( Ihuar lava
hill and Nun-ko-weap valley the Tertiary movement has carried the pre-
I : strata on the east of the fault entirely out of Bight, bringing
Carboniferous strata into contact with the pre-Cambrian Chuar series.

From these observations it appears that at the close of the pre-Cambrian
period of deposition of Bediments in this region, a change ensued that re-
sulted in the uplifting, as we now know, of 12,000 feet of Btrata, between
the sum mil of tie pre-Cambrian terranes and the A.rchean(?); and also, a
considerable portion of the A^rchean (?) to the southwest During this uplift,
or possibly later, a fault of considerable importance began on the line .it
the pie-, nt Unite fault, displacing the strata with a downthrow to the west
«,| from WO to 1,000 feet in the area now exposed to view. Tins movement
wa- probably prior to the planing to base level, by erosion, of the inequalities
ami irregularities of the Burface produced by the undulations and fault- in the
pr< -Tonto formations. The uplifting and metamorphism of the Btrata along
the line of the pre-Tonto fault, could scarcely have occurred without the
presenct of sufficient superincumbent rock to give the lateral pressure d
try to produce the phenomena observed bisections 1 . 1. 5, '''ami 7.

THE FLEXING ALONG THE FAULT. 59

The Tertiary movement has not perceptibly influenced or changed the
position of the upturned Algonkian strata. It was the reverse of that of
the Algonkian, and strata of various degrees of firmness were flexed upward
from the east. The massive Tonto sandstone curving slightly downward
towards the fault from the west (fig. 10), indicates that a portion of the fold
that preceded the Tertiary fault compressed the upturned Chuar shales, but
did not materially change their position in relation to the plane of the fault.

Upper Aubrey

Lower Aubrey

Red Wall

Tonto £ T.sd

Chuar

Figurk 10. — Ideal Section of East Kaibab Monocline.

Illustrating the position of the strata on the line of sections 4, 5, 6, etc., before the breaking of
the monoclinal fold, portions of which are preserved by the Tonto sandstone in sections 5 and 6.

The evidence of Tertiary flexing is clear and decisive. The massive Red
Wall limestone, 900 feet in thickness, curves up and bends over, taking a
westward dip, as seen in section 4. All along the line of the fault the sand-
stone, limestone and shales approach it at a high angle, and are frequently
in a vertical position as well as more or less metamorphosed. The study of
the probable conditions under which this upturning of the strata occurred
is very interesting, and opens up questions that have a bearing on the history
of the erosion of the Grand Canon.

In the diagramatic section (fig. 11) the relative positions of the Aubrey
limestone and sandstone, the Red Wall limestone, and the upper calcareous
and lower sandstone series of the Tonto group, are defined on both sides of
the fault. Dotted lines indicate the position of the strata on the west side,
out to the fault line, prior to their removal by erosion. The Aubrey lime-
stone has been eroded away in the immediate vicinity of the fault. The
subjacent sandstone approaches nearer, and its upturned massive beds are
shown in sections 4, 5 and 6. It is not, however, until the great Red Wall
limestone is reached that immediate contact with the plane of the fault
occurs. Here there is decided evidence of the lateral and vertical pressure
accompanying the displacement. The upper limit of the Red Wall lime-
stone has heen displaced, as shown in fig. 11, from x, on the west side
of the fault, to x on the east side, a distance of nearly 1,300 feet. This

60 C. D. WALCOTT — A DISPLACEMENT IN" THE GRAND CANON.

movement produced the upward Hexing of the strata, as is shown in
meet of the cross-sections of the fault, as well as by the alteration of the
Red Wall limestone. The latter formation received its flexure and local
metamorphism in passing by the rocks of the same geologic ago ami
also the Upper Tonto Btrata beneath, on the opposite or west Bide of the
fault Then- is m> direct evidence that the Aubrey limestone was also flexed
and metamorphosed, as ii is now removed by erosion from the vicinity of the
fault, but from the relations it bears to the strata below, as shown in sections
•1. 5 and 6, and in fig. 1 1 , there is little doubt that such was the case. This is
almoel absolutely proven by its partaking ol* the flexure of the fold, to the
north, in perfect conformity to the strata beneath.

Prom these considerations and the present relationsof the strata on the
opposite Bide of the fault, as given in rig. 11, it is evident that tin1 formations
(Upper A.ubrey, Lower A.ubrey, Red Wall, Upper Tonto, and Tonto sand-
stone) had not been eroded, within the dotted lino, at the time of faulting.

< )n the slope of the East Kaibab ibid, twenty miles to the north, the hard,
compact limestones of the summit of the Aubrey group form the surface
rock. The massive layers curve downward with the flexure of the fold, and
often large slabs, detached by erosion, retain the curvature they received.
When this Hexing occurred there must have been a considerable thickness of
Btrata above, exerting by its weight a powerful downward pressure. This
necessitates the presence of the Permian and more or less of the superjacent
strata over the east -lope of the Kaibab Plateau and the Grand ('anon
ana. Whatever other < litions of slow movement and lateral pressure

may have existed, a downward preS8Ure, as above indicated, was also
necessary in order to fold and flex the strata as they occur on the lii f

the Easl Kaibab displacement, both in the fold and on the line of the Butte
fault.

The Hull' Fault >ni<l the Grand ('anon. — It is stated in the preceding
paragraph that in order to explain the curvature of the strata near the fault
a considerable thickness of strata must have existed above the rocks now
exposed to view. With a thousand feet or more of strata above the area
now occupied by the Kaibab and the lower plateaus adjacent to the Grand
Canon, ii is difficult to understand how the canon could bave existed even
to a limited .hpth. in it- present position, al the time of the elevation of the
Kaibab Plateau. An explanation more in accord with observations on the
I tern Kaibab displacement is that while the uplifting of the plateau and
the Easl Kaibab displacement were progressing, the Colorado river w
cutting its channel down through the Mesozoic groups that then rested on
the Paleozoic rocks in which the presenl ••anon is eroded, and that, instead
of cutting a channel down through the limestones and sandstones of the
Paleozoic, u the plateau was elevated, it was cutting through the fold in the

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62 C. D. WALCOTT — A DISPLACEMENT IX Till: GRAND CANON.

superjacent Mesozoic rocks. Thia would influence the manner of the erosion
of tin- Grand Cafion, ami, if followed nut in all it- bearings, would probably
necessitate Bome change in the now accepted views concerning the manner of
the erosion of the broad outer ami narrow inner cafions, wesl of tin- BLaibab
division of the Grand Canon. At present tin- influence of the Butte fault
on the erosion of the area immediately adjacent to it will alone be noticed.

Fig. 11 shows thai as so in as the river reached the limestone on the west
of the fault, it would necessarily erode the softer strata on the east Bide until
the BUmmit of the Upper Aubrey limestone «;i> reached. If mar <»r on the
line of the fault, the channel would be deflected eastward by the slope of the
ita until it reached the base of the slope, leaving a strip of rock between
the river channel and the fault line. The cliff left on the west Bide of the
fault as the river deepened its channel, afforded the agencies of aerial erosion
an opportunity to do their work rapidly, and the debris was carried to the
river as soon as it fell on the limestone slope below. With the deepening of
the river bed, channels formed between it and the retreating cliff, and the
great buttes were marked off Subsequent erosion deepened the channels to
cafions and removed the strata on the west of the fault. When the base
line of erosion once reached the friable and easily eroded argillaceous Btrata
of the Ghuar group, the cutting away of the inner canon valley area advance d
at a rapid rate, until the havoc and ruin was greater than that accomplished
by the direct agency of the river in the cafion east of the buttes. To-day
the buttes rise high above the inner cafion valleys and guard them from the
ravages of the river, although they are 2,000 feet below the level of the
Kaibab plateau.

Analogy between tl"- Hurricane Fault and ili> Butte Fault. The Butte
fault i- only paralleled in the Plateau country, as far as known to me, by a
portion of the great Hurricane fault, north <»f the town of Toquerville, in
southern Utah. The upturning of the strata is there on a somewhat greater
Male, and it occurred in the earlier movement on the line of the fault, for
the upward flexing is from the east and the present downthrow is to the west.

The downthrow of the Hurricane fault north of Toquerville is estimated
by Captain Dutton to l>c over 6,000 6 i The massive Aubrey limestone

rises towards the fault from the east at an angle of from 25° to 30°, the
western face of the flexed Btrata forming a more or less broken cliff 1,000
feel in Keight. To the north the shear of the fault increases rapidly. Ten
miles distant it is estimated by Dutton at from 12,000 t<» 14,000 feet.
Tin- upturning of the Btrata from the east is also more marked north of
Canarra, where it curve- up to the vertical and is even reversed bo as to
have a westward dip of 1 •» for a distant f several miles along the fault.

Captain DuttOD -tale- that the thrown he. Is, on the west Bide of the fault,

curve down towards it. He explains this by the presence of a monoclinal

•miv History ..t ti,.- Qr»od Cafion m-tn

ANALOGY WITH THE HURRICANE FAULT. 63

fold on the line of the fault that had a downward curvature to the east.
The fault subsequently broke the fold and carried a portion of it down to
the west. This satisfactorily explains the position of the strata on the west
side of the fault ; but another explanation is demanded for the eastern up-
turning and the reversal of the strata on the east of the fault. This is found
in the data given for comparison, by the position of the strata in the sections
of the Butte fault (figures 5 and 11). Figure 10 illustrates the position of
the strata at the time of the monocline, of which Captain Dutton speaks ;
it being understood that the relative position of the strata in the two sections
and not the same geologic terranes are referred to. In sections 5 and 11 the
monocline is broken and the strata on the east dragged up towards the fault.
This is the position which I think the strata on the opposite sides of the
Hurricane fault, north of the site of the present town of Kanarra, occupied
before the reverse movement, accompanied by the downthrow to the west,
began. Erosion removed some of the upper strata, in all probability, but
the general section would have been similar to section 10, the dotted lines
representing strata present and not eroded as in the section of the Butte
fault. The evidence of lateral and vertical pressure on the upturned beds,
is the same as on the Butte fault. The subsequent downward movement on
the west, or the more probable elevation on the east, was unaccompanied by
sufficient lateral pressure to flex and reverse the position of the strata on
the east side of the fault, in the vicinity of Kanarra.

Paleozoic Movement. — Before giving a summary of the history of the East
Kaibab displacement, as interpreted in this paper, it is necessary to record
the observations upon which the existence of a movement at the close of
Paleozoic time is based.

West of the town of Paria, on the road leading from Paria, Utah, to House
Rock spring, Arizona, the upper beds of the Permian rise with the curva-
ture of the East Kaibab fold towards the west. The overlying Shinarump
conglomerate, the base of the Mesozoic groups, also rises, but not so rapidly,
and consequently thins out against the greater curve of the Permian. This
is still better seen in a section through the fold exposed by an east and west
canon. Erosion, at the close of the Paleozoic, cut into the Permian and
formed an eastward-facing cliff. The Shinarump conglomerate was subse-
quently deposited against and over this cliff, gradually thinning out to the
westward and disappearing against the rising slope of the Permian beds.
The cliff and the thinning out of the Shinarump are well shown in the section
forming fi^. 12.

The Shinarump does not appear again iu the entire distance across the
Kaibab fold. The massive upper stratum of brown sandstone capping the
Permian is also absent, and the clays of the Permian and Trias are in con-
formable contact, no evidence of a stratigraphic break being discernable.
From the fact that the massive upper stratum of the Permian also thins out

64 C. D. WALCOTT — A DISPLACEMENT IN THE GRAND CANON.

on the rising slope of'the fold, I am inclined to think thai the Blight move-
ment ni' this time was going on «1iiiIii ;_r the latter part of the deposition of
the Permian.

^^mmrmm

A
l he 12.— Diagramatic Section of the Permian Monocline.

Illustrating tin- thinning out of the upper Permian and the shinarump conglomerate against the
more highly inclined Permian strata beneath. (The ancient Permian cliff i- i by del

at the immediate base of the section.)

It is probable that the era of the deposition of the Permian was one of
slow movement of the sea-bed. Elevation and depression are indicated by a
strongly marked unconformity, by erosion, in the lower portion of the upper
Permian. This is shown by the unconformity in the Permian so well seen
in the buttes south of the Shinarump cliff, eleven miles Bouthwesi of Kanal>.
Utah. The sediments arc mostly detrital in character, and ripple-marks
and other indications of a littoral deposit are also seen at several horizons.
The evidences of the movement do not indicate that it was of great magni-
tude, l»nt rather the contrary. Sufficient is shown to prove that the incep-
tion of the great Tertiary displacement was in Paleozoic time.

From the close of the Paleozoic to the Middle Tertiarv there is no known
evidence of any movement along the line of the East Kaihah displacement.
Tin- intervening time appears to have been one of slow subsidence and quiel

deposit! f sediments. From the evidence given by Captain Dutton* it

i- scarcely to he doubted that the later displacements are of Tertiary age,
and that tli-' movement continued to a comparatively recent date.

/,'■ wme. — The history of the displacement IS briefly staled as follow-:

The Easl Kaihah movement began in the region of the Grand Caftan as
a pre-Cambrian faull displacing the older Algonkian strata, with a down-
throw to the west of from LOO to 1,000 feet. A period of rest then ensued
thai was broken, in the latter pari of Paleozoic time, by the formation of
an eastward-facing monoclinal fold of a few hundred feet. So far aa known

this movement ceased with the close of the Paleozoic, and Was not resumed

until Tertiary time. It tben began and continued until the Easl Kaihah
fold and the accompanying faull were developed ; the displacement aggre
gating over 2,700 feel in the vicinity of the Grand Caftan. This occurred
before the removal, by erosion, of the Permian and probably more or less
superjacent strata over the Grand ('anon area.

I. -', with artia I Cafioi

THE HIGH CONTINENTAL ELEVATION PRECEDING THE

PLEISTOCENE PERIOD.

BY PROFESSOR J. W. SPENCER, A. M., PH. D., F. G. S. (l. & A.),
STATE GEOLOGIST OF GEORGIA.

If, in the growth of the American continent, the moulding of the land
features had not largely depended upon its projection above the sea, favor-
ing or retarding the action of rains and rivers in sculpturing its surface,
there would be little interest as to what was its relative height, before the
commencement of the Pleistocene period. But w-e find valleys vastly greater
than the meteoric agents could have produced under existing conditions.
Thus, there are not only deep canons, but also vast depressions, descending
to levels far below the sea, which are now filled with the earlier drift ac-
cumulations, or form channels submerged beneath ocean waves, or constitute
basins occupied by lakes. Hence, in the study of the drift itself, in the
investigation of the lake history, or in the research upon the growth of
modern rivers, we necessarily inquire what was the altitude of the continent
that would permit of the mouldings and channelings of the original rock
surfaces.

Following the period of high continental elevation, the geologist sees in
the valleys and old channels, still below the level of the sea, and in the high
level beaches, an extensive submergence, succeeded by a re-elevation, but
not to the original height, when the continent was being chiseled out by the
ancient rivers. That this re-elevation is still going on is shown by the north-
ward tilting of the comparatively recent marine accumulations along the
St. Lawrence valley and Gulf coast, and the raised beaches in the lake region,
as well as by the shoaling of the waters of Hudson's Bay during the present
period of observation.

As general statements do not satisfy investigation, it becomes necessary
to search for definite measurements of the former height of the continent
among the archives of the geological past. Let us first seek for the testimony
recorded by the Mississippi river.

For the distance of eleven hundred miles, measured in a direct line, above
the mouth of the " Father of Waters," the modern valley is merely main-
taining its own size, or more generally is being slowly filled by the deposition
of river alluvium upon its floor. There are only two exceptions, of a few
miles each, where the river is scouring out the rocky floor, and these are
over barriers recently exposed there during changes of the Pleistocene

IX— Bull. Geol. Soc. Am., Vol. 1, 1889. (65)

66 J. W. SPENCEB — Illi. II CONTINENTAL ELEVATION.

period. To such an extent has the ancient valley or canon been filled, first
with drift, and this covered with river alluvium, that its original rocky floor
is now buried to a depth of 170 feet, even at La Crosse, a thousand miles from
the Gulf of Mexico. Farther south the depth of these loose deposits in-
creases, until at New ( Orleans a boring of 6.30*)" feet below sea level does not
penetrate the southern drift, nor even reach to its lowest members. The
lower 500 miles of the ancient Mississippi were excavated out of Eocene or
Cretaceous deposits, whilst the valley above the mouth of the Ohio has
the form of a canon, excavated out of Paleozoic rocks, varying in width
from ten to two <>r three miles, and having a depth (exclusive of the portion
now filled) of from 150 to 550 feet, according to the late General G. K.
Warren.

From this inspection of the river, it is easily seen that no natural rainfall
could so increase the volume of the discharge as to remove all the deposits
which now fill the old valley, much less excavate the original and immense
canon. A vastly greater elevation of the continent was necessary. Even
were the whole continent uniformly elevated 630 feet, together with the re-
mainder of the unknown depth of the ancient Mississippi river, at New
Orleans, the canon of the upper part of the river would require a still
greater relative elevation of the northern country in order to give sufficient
channeling power to the flowing waters; but the slope of the floor of the
partially buried valley is much less than that of the modern, as was formerly
shown by the author.]; Here, again, is the proof that the country drained by

the upper waters of the Mississippi once st 1, relatively to that in the region

of its mouth, much higher than at present. Of the amount, which was at
least many hundreds of feet, we have no absolute measurement; nor can we
ascertain it by calculation, for there is no register of the excess of the amount
of rainfall during the epoch of the greatest sculpturing over that of the
presenl day.

Whilst these records of the Mississippi, which have been only partially
deciphered, do not furnish all of the desired information, yet as far as they

•_'.. they arc invaluable.

Passing from the buried channel of the Mississippi to its continuation, now
submerged beneath the waves of the Gulf of Mexico, we find evidence indi-
cating such a stupendous continental elevation as to be almost incredible,
were ii doI supported by collateral evidence, upon both the Pacific and

antic coasts The Boundings off" the coast of the delta of the Mississippi in-
dicate the ouier margin of the continental plateau a< submerged to a depth of
3,600 feet, indented by an embayment of another hundred fathoms in depth,
at the head of which there is a valley a few miles wide, bounded by a plateau

. ol, [,1883 ;
w. B Heard, Km. Jour. Be, 2nd Ber., Vol. XI. \ III, 181 I, p .'.33.
I Am. .Nut., Vol. XXI, 1887, pp. 168-7L

SUBMERGED CANON AND FJORDS. 67

from 900 to 1,200 feet above its floor. This valley is now submerged to a
depth of 3,000 feet, and is the representative of the channel of the ancient
Mississippi river, towards which it heads.*

On the Pacific coast, in the region of Cape Mendocino, Prof. George
Davidson has identified three valleys now submerged to from 2,400 to 3,120
feet, and several of inferior depth. These measurements are those of the
valleys where they break through the marginal plateaus of the continent,
at about six miles from the present shore, where it is submerged to the depth
of a hundred fathoms, f

The soundings along the Atlantic coast reveal similar deep fjords. The
long-since known extension of the Hudson river, beneath the Atlantic
waters, is traceable to the margin of the continental plateau, acquiring a
depth of 2,844 feet, in front of which the soundings show a bar, covered with
mud, which however is now submerged to the depth of only 1,230 feet.
The unpublished soundings off the mouth of the Delaware river bring to
light another valley, the floor of which is now covered by ocean waves to
nearly 1 ,200 feet — its continuation seaward not having been ascertained.!

Were the continent elevated only 600 feet, the Gulf of Maine would be
replaced by a terrestrial plain, in some places 200 miles wide, but traversed
by rivers, one of which, towards its mouth, would be 2,064 feet deep — that is
to say, the bottom of the fjord is now submerged 2,664 feet. Even this
great depth may not be its maximum, for along the line between the oppo-
site banks, at the mouth, now beneath a hundred fathoms of water (which is
approximately the depth to which the real margin of the continent is sub.
merged), we find that the sea is nearly 5,000 feet deep. Whether this
represents an embayment of the ocean setting towards the valley or a con-
tinuation of the fjord is not determined.

The St. Lawrence river and gulf bear the same testimony of the existence
of deep fjords extending from the rivers through the now submerged plateau
forming the margin of the continent ; and the lower part of Saguenay river
flows between stupendous walls and constitutes a fjord whose waters
reach a depth of 840 feet. In the St. Lawrence river, a little below
the mouth of the Saguenay, there is a channel 1,134 feet below the surface.
This increases in depth in passing seaward. In the region of the centre
of the modern gulf, the floor of the old channel is now submerged 1,878
feet, and the adjacent valley 1,230 feet; thus showing the canon as being
over 600 feet deeper. As at the mouth of the channel through the Gulf of
Maine, so at the mouth of that of the St. Lawrence, there is a deep chasm ;
for enclosed between the banks, a hundred fathoms below the surface, there
is now the depth of 3,666 feet, with water 2,000 feet deeper just seaward of

* J. W. Spencer, " The Mississippi River During the Great River Age," New Haven, 1884, p. 2.

fGeo. Davidson, Bull. Cal. Acad. Sc, Vol. II, 1887, p. 265.

X Appendix 13, Rep. U. S. Coast and Geodetic Survey for 1887 (1889), pp. 270-73.

J. \Y. SPENCEB — IIKill CONTINENTAL ELEVATION.

it. Although this ancient valley is over sixty miles wide at its mouth and
was a narrow channel, yet it is not as hroad as some portions of the modern

called river. The breadth of the submerged valley throughout it- wind-
in-- tor a Length of sot) miles or more, is remarkably regular, only gradually
increasing it- magnitude in passing seaward. Other and lesser channels are
visible in the soundings : thus, Bouth of the Straits of < 'anso, between Nova

»tia and < ape Breton island, there i- one 1,200 feel <l<\<, according to tin-

PROFOUND DEPTHS OP LAKES AND RIVERS. 69

British Admiralty charts, while adjacent soundings show less than 600 feet
of water.

Hudson's Bay rarely exceeds a depth of 600 feet, yet at the outlet the
channel is 1,200 feet deep. This depth increases in passing down the straits,
where the scanty soundings show 2,040 feet before reaching the mouth.
Here, in Hudson's Straits, the old valley is a chasm across a mountain sys-
tem, whose peaks, upon the southern side rise to 6,000 feet above tide. The
canon of the St. Lawrence also crosses the trend of two mountain systems?
but these are of no great height. The same is not true for any of the other
submarine valleys described.

The record of a former high continental elevation is again inscribed in
the depths of the Great Lakes — Ontario reaching to 491 feet below ocean
level, Superior to nearly as much, Michigan to 300, and Huron to 150 feet.
The lake basins are merely closed up portions of the ancient St. Lawrence
valley and its tributaries. Their distance from the sea would necessitate not
merely a general elevation of the continent, but also a greater amount of
elevation towards the head-waters of the system, as has been shown with
regard to the excavation of the upper portion of the ancient Mississippi
canon. The lake basins are all excavated out of Paleozoic rocks, except a
part of that of Lake Superior.

The soundings do not afford all the information that we desire, yet
they demonstrate the presence of submarine valleys reaching upon all our
coasts to depths of 3,000 feet or more. Again, the soundings show that
within comparatively short distances from their mouths the depth of the
valleys, below the surface of the seas, sometimes did not exceed from 1,200
to 1,800 feet, but that beyond, there was a greater increase in depth, within
the last few leagues.

Whilst depressions in the earth's surface are made and modified by terres-
trial crust movements, yet the leaving open of great yawning chasms is not of
sufficiently well known occurrence to attribute all of the submerged valleys
upon the American coasts to such an origin, especially when we consider the
great length of the submerged channel of the St. Lawrence river (800 miles),
its various windings, and its uniformly increasing size, until it passes into
the great chasm, just before it reaches the margin of the continent. The
idea of the excavation of these submerged valleys by glaciers — some of which
are outside of glacial regions even of the past — is too untenable for a moment
of serious consideration. Irrespective of the causes which have determined
the location of the channels here described, it appears that they have been
made one and all by the excavating power of rivers and lateral streams
pouring down the hillsides. These, together with the other meteoric agents,
have also to a greater or less extent removed the Paleozoic, and also the
Triassic rocks, from the depressions now occupied by the Gulfs of St.

70 J. W. SPENCEB — HIGH CONTINENTAL ELEVATION.

Lawrence and Maine, which have, however, been more or less affected by
terrestrial movements.

The length of time required to excavate the channels of these gnat rivers
commenced as for back as the Paleozoic days. However, the culmination

of that of tin- Mississippi was not until in the later Tertiary, before the
Pleistocene period. As the St. Lawrence, now submerged to a depth of
over l'_'i»<» feel for a distance of SiiO miles, is mostly cut out of rocks of the
Palm/Mir group, except a belt of the Triassic across the lower portion,
more or less involved in mountain uplifts), its antiquity must be very great.
The culmination was also probably in the later Tertiary era. like that of
the Mississippi, and the channels on the California coast, for then' are sub-
merged Tertiary rocks off the coasts of Massachusetts and Newfoundland, at
elevations much higher than the beds of the old channels.

Although the excavating forces took so many periods to form the valleys,
and required a high continental elevation, yet the extreme altitude of over
two thousand feet appears to have been of comparatively short duration,
for otherwise the deep chasms in which the submerged channels terminate
would have extended farther inland than we find them, and would have
been headed by more gentle slopes, in place of precipitous cliffs, over which
the waters of the former rivers were precipitated in great cascades. In the
fjords of Norway, merging into rapidly contracting valley.-, or headed by
great vertical walls, hundreds of feet in height, having the structure named
cirques, may be seen to-day the counterpart of the coast of the American
continent, when it- marginal plateaus stood 3,000 feet higher than at present;
yet Noi-wav stood once much higher than now, but was afterwards submer-
:. from which depression it has only recently been re-elevated bo that its
plateaus, close upon the sea, rise to three or four thousand feet, and its
mountain- -till higher. The old hydrography is more or less distorted by
warpings of the earth's crust, which, however, do Dot obscure the valleys,
although rendering the features somewhat more complex. The amount of
distortion has yet to be determined.

University of Georgia, August, 1889.

ANCIENT SHORES, BOULDER PAVEMENTS, AND HIGH-
LEVEL GRAVEL DEPOSITS IN THE REGION OF THE
GREAT LAKES.

BY PROF. J. W. SPENCER, M. A., PH. D., F. G. S. (l. & A.),
STATE GEOLOGIST OF GEORGIA.

Chapter I.
Characteristics of Ancient Shore-lines in the Eegion of the Great Lakes.

The land features throughout the lake region drained by the St. Lawrence
river owe their formation largely to the action of waves, sculpturing rocky
or modeling earthy shores. That the waves have not always been confined
to the margins of the modern lakes is seen in the sea-cliffs and beaches, from
which the waters have loug since receded. These features, still remaining,
are sometimes in the form of bold relief, and sometimes in the form of narrow
sand or gravel ridges, delicately traced over a flat country. In some places
these ridges approach near to the lakes ; in other localities they are miles
away, and at varying altitudes up to hundreds of feet above their present
waters.

The raised shore-lines are no longer water levels, for terrestrial move-
ments, since the lakes have receded from them, have commonly lifted
them up to unequal altitudes. Whilst some of these old shores represent
former lake boundaries, there seems to be little reason to doubt that the
higher sea-cliffs and beaches formed the coast of brackish water inlets or arms
of the sea.

Besides the deformation arising from the unequal terrestrial movements,
the shores have been in many places defaced by the action of rains, rills,
rivers, and landslides, until their broken continuity renders them somewhat
difficult to follow over long distances. The object of this chapter is to
describe the characters of the old raised and deformed water-margins, by
which they can be identified. The ancient coast-lines differ in no respect
from the modern, but they are often easier to follow, as there are no waters
to restrict one's footsteps. Were the lakes to be suddenly drained, but a few
years would elapse before the deserted margins would be as difficult to mark
out with precision as any of those from which the waters have long since
receded.

With notable exceptions, the lakes are generally bounded by banks of
clay or sand, stratified or unstratified. The waves have in places cut into

(71)

... W. SPENCEB — ANCIEN1 SHORE PHENOMENA.

these deposits, Leaving high clay binds, in other localities the coast r
gently from the water-line In front of these shores, whether high or low,
beaches often occur. The typical beach forma a ridge of stratified sand and
gravel, rising from three to five feet, or even inure, above the Burface of the
water. The ridge may vary from a lew yards to as many scores, or even
hundreds. In the mure perfect form, there is :i slight depression behind the
ridge which is sometimes occupied as a bay. lagoon, or swamp < fig. 1).

FIGURE I.— Section showing the Floor of a Cut Terrace on which rests a Bench.
'. and c = Beaches broken into ridgelets. d = A frontal sand bar. W= Old water-level.

Whilst the beach may form a frontal barrier, in shallow waterj distant from
the Bhore, it may rest directly against the coast, funning a terrace (a, fig. 2 ,
behind which there is no depression. In this case the surface of the terrace
is apt to he defaced by landslides or washes; but the beach, whether in the

Figure •-'.—> Floor of •< '/'■

f construction resting on cut terrace. P Frontal pavement of boulders. W Old
i r-level.

form of a terra< r off-shore barrier, Is very often wanting when the currents

are cutting into and washing away the coast i fig. 3). Under such a condi-
tion, if a beach he funned, ii is narrow ami temporary, a- it is liable to be
washed away or covered by landslides. The eastern ami southeastern coast
of Lake Huron commonly illustrate the absence of true beach structure.
Another excellent example may be seen at Scarboro heights, a few miles east
of Toronto, on Lake Ontario, where the clay banks rise to the heighl <>l'
more than 200 feel and extend fur a distance of uine miles. Here the cliffs
;ii'- being eroded. The waves are nut forming a permanent beach, but the
currents are drifting the materials Beveral mil.- to the west to build up the
barrier-beach in front of Toronto harbor.

COMPARISON OF ANCIENT AND MODERN SHORES.

In the formation of beaches there is a tendency to straighten crooked
coast-lines by the construction of bars iu front of inlets, which are thus con-
verted into bays or lagoons. Burlington bay, at the western end of Lake
Ontario, is an illustration. Here, a narrow beach (fig. 5) cuts off a bay five
►miles long, whose depth is considerable, reaching to 78 feet. This is a particu-
larly well-chosen example, for at the head of the bay there is a spit — named
Burlington heights (Ji, fig. 5), rising to 108-116 feet above the lake —

Figure 3. — Section showing the Floor of a Cut Terrace without Beach but with Boulder Pavement.
P= Boulder pavement. W= Old water-level.

cutting oft" an older bay, now represented by the Dundas marsh. This spit,
when the waters were at its level, formed a portion of an ancient shore (to be
described in a future chapter) in the same manner as Burlington beach
forms a portion of the modern lake-shore.

Figure 4.— Section showing a Cut Terrace with a fragment of Old Beach partly concealed by a Landslide-

6 = Boulder pavement. c = Fragment of old beach, d = Drift. s= Landslide, iv = Old water-
level.

In places, where the waves break upon the more exposed coast, the beaches
are apt to be piled up a few feet higher than their mean level. The oppo-
site result is seen where the ridges are fashioned as spits and pass below the
surface of the water in the form of submerged bars. The increase in the
depths of the water in front of the beaches is usually veiy gradual.

The study of the modern and ancient shores is reciprocal. By the former,
still washed by waves, we can identify the latter ; and by the examination of
the floors iu front of the raised beaches, we can more fully understand the
action of waves upon the modern coasts, than where the subaqueous deposits
cannot be seen. The muds, derived from the encroachment of the waves upon
the land, are assorted ; the coarser materials being those which form the

X-Bull. Geol. Soc. Am., Vol. 1, 1889.

.1. W. SPENCEB — A.NCIENT SHORE PHENOMENA.

beaches, atul the finer clay, that which constitutes the off-shore silt deposits*
leveling up the inequalities of the lake bottom and forming very flat Bub-
merged plains, which are rendered apparent upon the withdrawal of the
waters.

In the examination of old shores, the occurrence of flat or very gently
inclining plains, abutting at constant levels against rising hills is as certain
an indication of old coast-lines as if beaches were found there; but the
exact height of the water-line cannot be recognized, as the water may have
been five or it may have been twenty feet deep. When this condition
obtain.-, there may remain here and there a fragment of a temporary beach
(e, fig. 4), covered by a landslide (*, fig. 4), but exposed by a stream or arti-
ficial cutting into the hillside, or there may be a barrier in front of an
ancient bay or lagoon (h, fig. 5).

Whilst the greater proportion of the lake coast is composed of drift
deposits, there are places where the water-margins are bounded by rocks.
Here the structure is similar, although not so well developed, and the banks
may assume the form of vertical cliffs. Generally speaking, the beaches in

Fioubi 5.— Map of tht Wt I I io.

; Burlington beaoh, separating Burlington bay from the Lake, h Burlington h<
i 108-116 feet high, si-parating Dund.-i* marsh from Burlington bay.

front of tin se rocks are not bo well developed as where there haw been Bhore
deposits of boulder clay to supply the wave- with pebbles. However, some
of the higher and older coast-markings remain in the form of such "sea-
cliffs," in front of which there are compa rat ively fiat plains.

Another structure, when present, is very characteristic of many portions

of the ancient shores, or, indeed, is occasionally Been in front of the i lern

beaches. This is a pavement of boulders (derived from adjacent Bhores of
boulder claj , occupying a given /one (P, figs 2 and 3). This /one i- in
front of and a few feet lower than the level of the true beach ; the bouldi rs
baving been left just below the water-level as the wave- made encroachments
upon the coast. Again, the boulder- have been more or less pushed up to

BOULDER PAVEMENTS AND ANCIENT BEACHES. 75

this line by the waves forcing up the coast-ice to which these boulders have
been frozen. When these deposits occur adjacent to the modern beach, they
may be seen rising out of the water, but they are also found outward in the
lake to the depth of several feet (Plate 1, fig. 1).

In front of an elevated shore, the boulders may be arranged iu the form of
a zone, even a few hundred yards in width, throughout a vertical range of a
few feet, which may be increased to thirty or forty feet where there is a suc-
cession of beachlets close together, marking the gradual recession of the
waters. But the upper level of these zones never quite reaches that of the
beaches. In travelling along a flat country these pavements of boulders are
as certain indications of shore-lines as are any other forms of the beaches
(Plate 1, fig. 2). Boulders left on the hillsides by the action of rains, washing
out the finer materials of the drift clay, are not arrauged in belts of symet-
rical level. The boulder pavements do not usually occur where the adjacent
coast is not composed of boulder clay, nor where the beaches are separated
from the land by what is now or has been a bay or lagoon. Pavements of
boulders are not as commonly seen in front of modern shores as iu front of
some of those more elevated and ancient.

Turning to the more typical form of the beach structure, as shown in the
raised shores, there may be seen sand or gravel ridges, most frequently from
one hundred to sometimes five hundred feet across, rising to fifteen or
twenty-five feet above a flat or very gently descending plain, whose surface
is most commonly composed of fine clay. Sometimes this descent is so very
gradual as to be inconspicuous ; at other places the descent is quite sudden.
The depression behind the ridge is generally less than that in front of it, and
here also the floor may be composed of clay. When the beach is broad, it is
apt to be broken up into a number of ridgelets (e, fig. 1). Indeed, some of
the larger and more important beaches mark the recession of the waters by
separating into several ridges, often at considerable distances apart, each a
few feet below the preceding, where the lake floor is sloping very gently ;
but where the slope is more rapid, all unite into one large ridge. The beach
has rarely a thickness of more than fifteen or twenty feet, and rests upon the
clay or drift deposits, which constituted the floor of the former lake. As
the plain recedes from the shore, the materials become finer and finer clay
and freer from sand ; but at varying distances, of sometimes a mile or more
in front of the beaches, there may be found thin belts of sand resting upon
the lake deposits. Again, the beaches may take the form of terraces of con-
struction, resting against clay banks; or against these banks the ridges may
abruptly (but only temporarily) end like the modern beaches (b, fig. 6).

In measuring the comparative altitudes of a beach at different points, the
summit of a well marked ridge should be chosen, rather than that of the
beach in the form of a terrace (a, fig. 2) against the shore, or the junction

.1. W. SPENCEK — ANCIKNT SHORE PHENOMENA.

of the coastal plain back of a cut terrace (c, fig. 4) and the bounding hills, as
the exact water-level can here be only approximately determined. It is
more accurate to make the calculations as to the former water-levels from

the top of the ridges than from the foot of the beaches, as the slope in front

FlGUttE C>.— Plan of Bnrrier Beach in front of a I by Hills.

6=Line of Hills, s— -Barrier Beach. The beach ends abruptly on the left.

of tlu'in i- steep in one place, and in another very gentle, but the summit is
easily recognized. Where the beach itself is absent, by tracing the coastal
line, there will be found sooner or later, a bar or spit in front of some
river or extinct bay.

In ascending from the modern lakes to the highlands, several old shores
must be crossed. The country may be described as a series of terraces or
steps, whose frontal margins are moulded into hills, and whose surfaces are
plains, most commonly ol clay, although Bometimes of gravel or sand, at
the back of which, there may be found the beach in some form. These
gi ntly rising terrace plains may each be several miles in width — and con-
sequently the beaches several miles apart — or they may be narrow with the
beaches close together. In many regions, the old shores behind these plains

rise and extend across the country as < spicuous ranges of hills. The

plain.- themselves are occasionally eroded by b1 reams, until the whole country
is very broken. This is more likely to be the ease with terraces of the

greater altitudes, and here the more recent sui face erosion has often rendered
the ancient shore lines hard to follow.

In crossing a Beries of beaches, the lowest is found to be composed of the
Bnesl gravel, or indeed perhaps of sand. In this case it is apt to be more

or less leaped into dunes, by the action of winds. The ridges are often

divided, but the branch* a unite again, or else Bend out spits ending abruptly.
iasionally the materials from which the beaches were formed \\a< Btony

-and, in plat f -tony clay. Here, then, the extinct water-margins are

difficult to determine, for there is no -harp lithological character, as where a
beach a clay plain to mark the boundary between the Band beach —

commonly heaped into hummock- or dunes- and the frontal plain composed
of Band.

THE VARYING CHARACTER OP ANCIENT SHORES. 77

Many of the upper beaches overlie drift deposits, but those of the lower
elevatious are more likely to rest upon stratified clay — the sediments carried
into the deeper waters whilst the lakes were at higher altitudes. The char-
acter of the materials underlying the beaches is commonly the same as that
forming the surface of the plain in front of the ridges ; but its structure is
best shown in sections exposed by the subsequent erosion where streams cut-
ting through the ridges cross the plain. When such streams have been large
rivers, as has often been the case, there may be some trouble in tracing the
continuity of the beach, especially across a broken country, as a portion of
the valley may be older than the beach, which may swing around and skirt
the embayment, or form a bar across it. Or again, the beach may be only
represented by conical or other shaped sand or gravel hills, which were delta
deposits at the mouth of a former river. Such delta deposits may not rise
to the level of the former body of water.

With the varying conditions here set forth, which the shore-lines undergo,
the traveller, in coasting around the old lakes, can rarely proceed more than
a few miles without meeting obstructions. When the beaches ax-e a consid-
erable distance apart, with perhaps only fifty or a hundred feet of difference
in their altitudes, there is a liability of getting off one series and upon
another. Consequently it is often necessary to resort to accurate levelling,
allowing for reasonable variations in the height of the beach, and the diff-
erential elevation of the region, since the waters have receded from the
former shores.

In some regions the former expansions of the lakes were occupied by archi-
pelagoes. Consequently, there is an absence of continuous beaches, and the
explorer must depend upon following the plain, which formerly constituted
the lake-floor, finding here and there a fragment of the ancient beach, either
upon the coast of the mainland or upon that of an island. Here again, it
may be necessary to resort to accurate leveling to identify the beaches.

Whilst steep coast-lines may be followed through wooded regions, it is
most difficult to trace satisfactorily a beach across such a country. The
greatest difficulties are found where the ancient beaches enter regions that
are composed of hills of crystalline rocks, more or less wooded, and iuter-
spers d with numerous lakelets. In such places, there are numerous gravel
hills whose relationship to the old shores is not readily discernable.

In some places, the surface of the beaches is composed of nearly clean
gravel or sand ; elsewhere, from some admixture of clay, it becomes
more or less earthy soil, to a depth of two or four feet, somewhat obscuring
the beach structure. Again, there may be coarse stones resting upon its sur-
face, as if these had been forced up after the beach had been formed, by a
slight rise of the waters, or by the action of coast-ice, pushing them up.
However, these must not be mistaken for the more ancient gravel beaches,

7^ .1. \V. BPENCEB — ANCIENT SHORE PHENOMENA.

covered with drift, such as frequently exist, and will be described in another
chapter.

The beaches, in the form of narrow belts of gravel or -and. crossing a Hat
country, were in many places used as trails by the Indian aborigines, and

in some places these trails have been turned into roads, as they arc always
dry during the muddy seasons. These ridge-roads have attracted attention
as ancient beaches for nearly a century. Hut the water long since withdrew
from them owing to the elevation of the continent, which has been accom-
panied by their distortion from the water-plain, on account of an increasing
rise to the north and east.

The great geological value of investigating the raised ami ancient coast-
lines lies, not only in gaining a knowledge of the former expansions of the
lakes and their relationship to each other, hut particularly in being able to
make use of them, as old water-levels in order to measure the amount of
deformation or warping of the earth's surface caused by terrestrial move-
ments, resulting in the development of the basins of the lakes themselves,
and other features. Whilst the old shore-lines record a greal amount of

unequal terrestrial movements, yet these movements have also left n "ds

in the older sea-dills.

Chapter II.

BOTTLDBB l'.\ v EM r.\ P8 \ M> Fi;l SO

In many localities of the northern pari of our continent, the land surfaces
are almost covered with loose boulders, varying from the Bize of cobble
Btones to masses commonly three or four feel long. ( Occasionally the blocks
have a length ofeighl feet, hut rarely longer. WhilBl some of the bould<
are angular Mock- of Paleozoic limestones and sand-tone- of local origin,
the greater proportion are Archaean rocks, which have been transported
from the Canadian highlands, north of the greal lakes, to a distance of
sometimes three or four hundred miles. These crystalline rocks, although
bo bard and compact , have the angularities invariably removed. I! lock < are
frequently -ecu at altitudes of hundreds of fee; above their original sources-
Throughout the lake region, and the country north of the line of the south.

em limit of the drift, which is open fringed with them, the accumulation

of'boulders is not uniformly distributed. The country enclosed by that line
i- occupied liy sh< 1 1- and ridges of drift materials, through which the bud-
jacenl rocks occasionally protrude. Again, these plains and hills have their
surfaces moulded by the action of the waves of vanished seas or shrunken
lake-, often fashioning the region into a succession of broad terrace flat- and
billy coast line.-. It i- upon the surfaces of these moulded features that the

DOUld* rs are found. \\'hil.-t tie n are \a-t area- where there i- not a Bingle

ACCUMULATIONS OF SURFACE BOULDERS. *79

stone to be seen, and others where only an occasional block occurs, as if
dropped down from some meteoric source, there are other localities literally
so covered with large boulders as to prevent agricultural pursuits. These
boulder accumulations are superficial and do not peuetrate the subjacent
earths. They occur along certain zones, outside of which they are not
found.

The presence of these surface boulder accumulations has been most com-
monly explained alike by those who believe in the glacial origin of the drift
and those who do not, as having been dropped by melting icebergs at the
close of the drift epoch. A few glacialists regard these boulders as having
been deposited from glaciers where they now rest. It has also been hinted
that they have been left upon the hills, as the finer materials of the boulder
drift have been washed away by atmospheric agencies ; but it was only since
the recent systematic studies of the high-level beaches, compared with modern
lake shores, have been made that the natural explanation of boulder pave-
ments and distribution of erratics become possible.

There are three conditions under which boulder accumulations are found.
The most important is where the boulders form pavements stretching as belts
across a level country, usually in front of ridges which once constituted old
shore-lines, or forming zones of stones resting upon hillsides or capping the
summits of ridges. Of lesser importance is the occurrence of blocks scattered
sparsely and irregularly on the sides of hills. Lastly, occasionally erratics
are found alike over the hilly and over the flat country. That the boulders
were brought from their original sources in the later Pleistocene days and
dropped by either icebergs or glaciers where we now find them is an unten-
able hypothesis, for their birth places are now often covered with the older
drift or are hundreds of feet below the elevations where they are now found.
The relation of the boulders to the older drift are such that the erratics can
commonly be recognized as of secondary origin, being derived from the
earlier accumulations of boulder clay or sand. The manner in which the
blocks have been brought to the surface has been by the removal of
the finer earths from the drift, principally by the action of the waves or
currents enci'oaching upon the hills or ridges of such materials, charged
with occasional boulders. Thus the coast-line has been moulded into steep
shores, in front of which there is the gently descending plain, once sub-
merged— the floor of a terrace since the recession of the waters (figs.
2 and 3).

Thus the boulders throughout the whole thickness of the drift, which were
too large for transportation by the waves, were reduced to water level and
were accumulated upon the floor in the form of pavements or fringes
along the former water-margins. The removal of the earth beneath the
boulders continued until they had settled to the maximum depth of wave

.1. w. SPENCER — A.NCIENT SHORE PHENOMENA.

action below the Burface of the water, for at greater depths the fine earth
would not have been removed from beneath the stones. The vertical range
ofthe fringes is from fifteen t>> twenty-five feel or more when the recession

•

Hi' the former waters was gradual, leaving a close succession of beaches. The
width ofthe pavements varies from a few hundred feel to perhaps a half a
mile, according as the Blope is somewhat steep or very gradual. When the
finer materials were entirely washed oul into deeper water, then the mar-ins

• be plains, at the fool ofthe old coast-line, are simply fringed with boulders ;
but when the liner materials were assorted by the waves ami currents, the
Bands and gravels have been formed into beaches, usually a few feet above
the level of and behind the boulder belt.

But the storj ofthe boulder pavements and fringes is nol yet complete.
I ist-ice lias also played an important part in the arrangement of the pav-
ing Btones. The wave-, acting upon the coast-ice wherein boulders have
been entangled, cause the st-m- to he forced up into more regular /.ones,

■ . height, than would be affected by the residuary deposition alone, as
1 1 1 — t described. Blocks of large size can thus be moved, not merely by the
heaving action of modern frosts, but by the action of coast-ice itself; for
boulders upon the margins ofthe St. Lawrence river, weighing seventy tons,
are known to have been shifted by the spring vements of a winter's ice.

ain, the writer has seen upon some of the shores of Shoal lake, in
Manitoba, situated in a flat drift-covered country, modern beaches composed
of huge boulders, piled up by the waves of the lake acting upon the ice in
which the -tone- were enclosed, as otherwise blocks four or six feel long
could not be gathered from the shores of the lake and accumulated into
beach ridges, nor could they have been residual pavements as above
described, for no high shore- of boulder clay occur into which the waves

,ld have made encroachments.

An excellent illustration of the modern formation of boulder pavements
and fringes may be seen upon the shore- of Georgian hay, between Thorn-
bury and < k>llingwood, as -how o in Plate 1 , fig. '_'. There Lhe lake wave- are
encroaching upon a shore composed of boulder clay. The larger stones

nt in the water arc too heavy to be materially affected by the

waves or ice action. Excellent illustrations of boulder zones are found a
-hoit distance from this locality, at an elevation of 1*7 feet above the lake,

how n in Plate I . fig,

< nhcr i samples of fi f boulders high above any modern waters may

miles beyond the eastern end of Like Ontario. 'The same is

true u | the northern Bide of the lake, as for example, back of Trenton and

•ward : these are parts of and in front of the finer gravels of an old beach,

i han four hundred feet above the lake. Westward of Toronto,

where the old Paleozoic in place of drift, the boulder

from thi front of the beach.

1. 1889.

BULL. GEOL. SOG. AM. !

FlG. 1.— MODtRN BOULDER PAVEMENT ON GEORGIAN BAY
EAST OF THE END OF BLUE MOUNTAINS OF COLLINGWOOD, ONT.

FIG. 2— ANCIENT BOULDER PAVEMENT OF ALGONQUIN BEACH
whose crest rises 187 feet above Georgian Bay) upon the N. E. side of Blue Mountains of Collingwood, Ont.

DISTRIBUTION OP SURFACE BOULDERS. 81

Upon the steep hillsides, as along the Mahoning valley, near the crossing
of the Ohio-Pennsylvania line, there are zones thickly covered with boulders.
There we find the records of old water-margins, as well as in the pavements
associated with the well marked beaches and shore-cliffs facing the lake
basins. The finer materials have been washed out of the associated drift to
form bars, in the valley, which was once filled with water. On some
of the higher hills between the southern part of Georgian bay and Lake
Huron, to the west, the tops of ridges are covered with boulder pavements.
These ridges were islands in a former expanded lake or sea, whose surfaces
were encroached upon by the waves, until they were reduced to partially
submerged reefs covered with great erratic blocks, as the finer mud was borne
into the deep water. That these were island shores may be seen from the
boulder covered ridges, although miles apart, being reduced to a common
altitude.

On the hillsides, behind the fringes, there are only here and there irregu-
larly deposited blocks, exposed by the action of rains. Besides, the meteoric
effects upon any of the hills are small, compared with the encroachments
of the waves, in exposing enough stones to make boulder pavements.

The occasional erratic blocks often reposing upon fine lacustrine deposits
are of little importance, and indicate only an occasional stone entangled in
old coast-ice from an adjacent shore, when the region was covered with
water, just as the boulders resting upon the sunken ships in the mouth of
the Baltic have been deposited from the coast-ice moving out of that sea.

The study of the relation of the pavements of boulders to beaches sets at
rest the speculation upon the origin of these fringes, and obviates the necessity
for appealing to either icebergs or glaciers in later Pleistocene days to account
for the erratics, popularly called "hard heads," which are scattered over
the country in the form of pavements or fringes ; for these are usually seen
only where they can now be referred to some old coast line, or a succession
of shore lines, acted upon, in former days, by frost and coast-ice.

Chapter III.
High-Level Gravel Deposits in the Region op the Great Lakes.

Rather than rummage through the talus heaps of geological literature for
the different kinds of gravel deposits which may represent beach structure,
it is easier to go into the field of observation and investigate those forms
which may be modified beaches, or be related to, or be mistaken for them.
This method is the more satisfactory, as the geological literature often con-
founds different forms, and leaves others unnoticed, or not considered in the
light of the present investigation. The object of this chapter is to describe

XI— Bull. Geol. Soc. Am., Vol. 1, 1889.

.1. \V. SPENI i:i: — ANCIENT SHORE PHENOMENA.

the various kinds of gravel deposits, which resemble or are related to beach
Btructure,and aol to consider their occasionally doubtful origin or distribution.
Exclusive of the beds of sand, which are intimately connected with the
stratified clays, or included in the drift accumulations themselves, and the
ancient shores already described, the following groups of gravels and
Bands Bhould be noticed, some of which are covered with the stony clay of
the upper till :

I. Tht gravels and sands which are buried beneath the upper drift deposit*.
These may lie divided into (a) buried beaches ; and (b) more or less irre
nlar beds ami ridges of gravel ami sand, often of earthy texture, having a
more or leas tumultuous structure, and resting beneath accumulations of the
upper till.

II. Surface accumulations of gravels and sands, forming ridges, mounds
and plains. These are in the form of (a) the so-called osars and kames;
(b) other ridges and mounds resembling the last, but having a position cor-
r< sponding to that of beaches, in front of more elevated plains or drift hills,
"i- of the accumulations included in group 16; and (c) gravel plains.

I a. — Hitherto, the buried beaches have not been distingui-hed from
other bed- of gravel and sand intercalated within the drift formations. As
Mich accumulations, whose structure is the same as that of modern beaches,
are only exposed in sections cut through the surface deposits by streams or
artificial excavations, all of the knowledge that we can, at present, bope to
acquire, is the recognition that there were beaches, now covered by drift,
older than those upon the surface of the country. When beds of gravel
and Band are met with in borings, it is not always possible to distinguish
those which arc buried beaches from others which are intercalated with drift
deposits. The -t ructure of the buried beaches docs nol show that tumultuous
crumpling, so commonly seen in the next kind of accumulation- 1 1 I,). In
some place- the gravels are found cemented into conglomerates. Thin layers
of -tony clay, constituting the upper till, which cover- vast areas of the
country throughout the lake region, often rest conformably uj the un-
disturbed .-uiface- of the buried beaches, that may have a thickness of
twenty feel or more. Excellent example- of buried beaches may be seen
along the Au Sable river, near Lucan, Ontario, where the overlying drifl

clay is only four or six feel thick. When the covering is thin, there i-

letimes b liability of mistaking these older beds for those belonging to

the beach epoch proper.

I b. -The internal structure of this kind of gravel and sand deposits Bhows

atification, winch may be regular in one place, but the beds - i become

tumultuous, that is, the beds become irregular, bent or twisted, and confused.
Tic material- are apt to be somewhat earthy. Throughout these Layers
tier.- may ocmr occasional boulder- of large Bize, and pockete of gravel,

DRIFT BURIED GRAVEL DEPOSITS. 83

whose outlines resemble those of boulders (as if the gravel had been cemented
into masses by frost and then moulded into boulders, and afterwards deposited
in the frozen state. By the characters just given, these accumulations can
be readily distinguished from those of true beaches. They are commonly
overlain by a few feet (perhaps ten or twenty) of stony clay or other ma-
terials of the upper till. Occasionally the covering may reach several times
this thickness.

The external form of these deposits, with their clay mantle (which last is
dependent upon the form of the underlying gravels), may be that of undula-
ting plains, or these undulations rising to the magnitude of ridges and hills.
In this case, the ridges rise in succession one above the other, until they
reach an altitude of a hundred feet, or even more, above the plains which
are commonly in front of them. They may occupy a breadth of several
miles across the country. The ends of the ridges often overlap, and at other
times send out spurs, and enclose kettle-like depressions, which are liable to
be confounded with or not separated from those of the next group. These
ridges form a considerable proportion of the so-called moraines of America.
These slightly covered sand and gravel deposits are not so commonly devel-
oped below the altitude of 700 feet above the sea as at higher elevations,
for the lower country is more apt to consist of terraces, cut in the drift, and
of lacustrine deposits and beaches. But these accumulations cap the ridges
of the great chain named the Oak hills, which extend for over a hundred
miles in length, parallel to the northern side of Lake Ontario, at an eleva-
tion of from 900 to 1,200 feet above the sea. Farther west, such are also
the capping materials of the country, which is 1700 feet above the sea. The
same holds true for Michigan and other States.

II. — The gravels of this group are not only well water-worn but also well
washed and free from earthy matter. Indeed, they are sometimes free from
the finer sand. The pebbles are often coarser than in the lower beaches, in
some cases forming accumulations of almost cobble stones. There are
occasional boulders in the mass, but these are more common upon the surface.
The materials are mostly of local origin, with a small proportion of trans-
ported crystalline stones. None of the materials have been derived directly
from the subjacent Paleozoic rocks, but secondarily from the assortment of
the stony boulder clays. The gravels with their accompanying beds of
sand, when these are present, are stratified as in beaches, without anything
of the tumultuous structure of the last group. Still, there may be false
bedding, as in beaches; and when the deposits assume the form of ridges, the
layers may dip in opposite directions, as in barrier beaches. The materials
of this group are never covered with drift deposits, but often rest upon the
till, or against hills of the tumultuous accumulations already described.
In 'external form, the gravel deposits differ greatly, and it is upon this
character that they are divided into the three series.

.1. W. SPEN< EB — ANCIENT SHOBE PHENOMENA.

II and Karnes. — The osars (Anglicized from the Swedish word

Isar, meaning gravel hills) being the term in America applied to very
narrow gravel ri< den only a few score yards in width at the base)

or chains of mounds, winding in a more or less serpentine manner across a
comparatively flat country, above which they rise at nearly as steep angles as
the loose mat. rial will stand to a height of forty or sixty feet. They are also
defined as generally extending from a higher to a lower country and follow-
ing the course of the greater valleys — that is, at right angles to the coast
Lines. A beautiful example of an osar, as above described, is to be seen
southeast of Lansing, Michigan. It trends into an inlet among the hills,
oblique to the general direction of the ancient coast. Driving along the top
of the ridge, which i- scarcely wider than the road, it is seen to be composed
of constantly and suddenly alternating stretches, each quite level, the one

being about twenty-live feet above the other. These so-called osars form
a very limited proportion of the gravel ridges of this group.

The term kame ( the .Scotch vernacular for gravel hill), according to its use

in America, is described by Chamberlin as "assemblages of conical hills and

short irregular ridges of discordantly stratified gravel ; between which are ir-

:ilar depressions and symmetrical bowl-shaped hollows that give to the
whole a peculiar, tumultuous, billowy aspect. . . . These irregular accum-
ulations are, however, more abundant in connection with deep, rapidly descend-
ing valley.-, being especially abundant where they are joined by tributaries
or where they make a sharp turn in open portions of their valleys, and
especially where they deboucb into an open plainer country. In such
instances they are usually associated with gravel terraces and plains. Pre-
cisely similar accumulations are very common associates, if not constituents,
of terminal moraines. . . . They are transverse to the slope of the
.-urfncc, the course of the valleys and the direction of the drift movement
1 i urn observation in nature, as also from the description itself, it
will In- seen that the term kame is not specifically used, and that differ-
ent kinds of gravel deposits are grouped under the same name. Indeed,
from the above description, the term mighl be better applied to some of the
deposits described above under group I b, which are more or less covered
with clay. However, there are < icaland tapering ridges in many localities

without a tumultUOUS structure, whose relations to each other are not easily

discernable, that may he placed here under the name of kame. Some of the

kaiie- in the valleys are doubtless river deposits, and others are the remains

oi uncovered buried beaches of greater age, exposed l>v subsequent erosion.

II //. — 'fhe internal structure of this series is similar to that of the other

members of the group. The external form is that of intermittent ridg

- rising to sixty feel above a frontal subaqueous coastal plain

hlrd Annual !•• , ,i Survey, L883, p. 800.

SURFACE GRAVELS AND SANDS.

which is occupying the position as in front of a beach. The ridges may be
replaced by cones, resembling delta deposits. The ridges are often scarcely
less direct and scarcely more broken or more varying in height than beaches,
especially when the subsequent erosion and unequal elevation, caused by
terrestrial movements since the gravels were deposited, is taken into account.
The ridges are often found to divide and enclose kettle-like depressions,
sometimes dry and sometimes containing ponds or lakelets, just like similar
depressions along modern beaches, but on a larger scale. Branches and
spurs add to the undulating appearance of the country. In front of these
hills the plains may be covered with gravel. It is very difficult not to see
in these ridges the remains of beaches belonging to former shore-lines. A
single ridge of this character occurs behind a plain just north of Stouffville,
Ontario, rising to a height of seventy-five feet above the plain, which is
about 1,100 feet above the sea. This deposit rests against another and some-
what larger ridge of sand and gravel belonging to group I b. Again,
within a distance of about fourteen miles, stretching northwestward from a
point near Flesherton (shown in fig. 7), there are three steps, each in the
form of a slightly undulating plain, often paved with gravel, bounded by
just such hills of gravel as are here described. These marginal ridges
are much indented with kettle depressions (k, k, fig. 7), and are somewhat

Figure 7— Section extending Northward from near Flesherton.

b = Boulder pavement. g, g = Ridge.s of Artemisia gravel, k, k = Depressi' as behind the
gravel ridges.

beneath the level of well-marked terraces, as if a somewhat off-shore
deposit. The elevation of the country above the sea descends from 1,600
to 1,200 feet. The ridges (g, g, fig. 7) border a mass of land that was rising
out of, probably, the sea. The beach-like character of these accumulations
is further brought out by the occurrence of zones of boulder pavements at
levels below and immediately in front of the ridges (b, fig. 7). These
boulder pavements, which do not enter the mass of the drift but only rest
upon its surface, are too characteristic of the action of waves cutting into
stony drift and of the accompanying action of coast-ice not to be regarded
here as additional evidence of the coastal formation of the surface gravel
ridges, described in this paragraph.

J. \V. SPENCEB — ANCIENT SHORE PHENOMENA.

"Artemisia gravel" is a Dame applied by the Canadian Geological Survey
to the gravels covering an area of 2,000 square miles of the highest land in
Ontario, between the three hikes. Buron, Erie, and Ontario, rising in places
to 1,700 feel above the sen. But the Canadian Survey did not recognize
the different kinds of gravel accumulations. Indeed, its whole work upon the
drift of Ontario was only pioneering, and now being somewhat antiquated
and generalized, it is but a poor guide along a pathway enlightened by
modern investigations. Thus the term Artemisia includes sand, gravel, and
even upper till deposits (the last, although occupying thousands of miles
of the Burfaceofthe Province, was not identified by the Survey) of all kinds
and ages mentioned in this chapter and in that on beaches. However, it
was the accumulation of the gravels described in this group II b, in the
township of Artemisia, that gave the name which was extended over such a
wide range of materials and geological time as if all were one formation.
At most, the term should be restricted to the ridges occupying the position
of very high-level beaches, just described.

II e. — Gravel plains are common in front of such highdevel ridges as
have been last described, representing the subaqueous floors when the waves
beat upon the old shores. Some of them, however, may be the floors of
terrace- cut into the older gravel deposits. The plains are often very deeply
eroded, owing to the high elevation of the country and the long action of
meteoric agencies upon the incoherent materials. Thus, there sometimes
remain of these plain- only a succession of ridges, between ravines deeply
excavated by the numerous streams and floods. Such plains occur in the
typical region of the Artemisia gravel in Ontario, in .Michigan, and in
other States.

University of <i'><>r(/ia, August, 1889.

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA

Vol. 1, pp. 87-98

ORIGIN OF THE ROCK PRESSURE OF NATURAL GAS IN
THE TRENTON LIMESTONE OF OHIO AND INDIANA

EDWARD ORTON

WASHINGTON
PUBLISHED BY THE SOCIETY

March, 1890

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA

Vol. 1, pp. 87-98. March 1, 1890

ORIGIN OF THE ROCK PRESSURE OF NATURAL GAS IN
THE TRENTON LIMESTONE OF OHIO AND INDIANA.

BY EDWARD ORTON.

(Read before the Society December 26, 1889.)

CONTENTS.

Page

The Importance of the Product 87

The Kock Pressure 88

Theories of Origin of Rock Pressure .__ 89

The Data for the Hydrostatic Theory 90

The Test of the Hydrostatic Theory 92

The Laws of Gas Production 93

The Duration of Gas Supply 94

Discussion 95

The Importance of the Product.

Natural gas derived from the Trenton limestone has supplied during the
last year and is now supplying all the fuel and a considerable part of the
artificial light that is used by at least four hundred thousand people in
northwestern Ohio aud in central Indiana. Within the same limits it is the
basis of a varied line of manufactures, the annual product of which will make
an aggregate of many millions of dollars. More than forty glass furnaces,
not one of them three years old, are now in very successful operation within
the territory named, while iron and steel mills, potteries and brick works,
and a long list of factories in which cheap power is a desideratum, have been
built up on all sides with wonderful rapidity.

The largest gas production of the Trenton limestone that has yet been
reached is to be credited to the present year. A well drilled early last
summer at Stuartsville, six miles north of Findlay, produced through the
casing, a pipe 5 1 inches in diameter, 28,000,000 cubic feet 'of gas every
twenty-four hours. There are but few wells in any field that exceed these
figures. Most of the wells so reported have been estimated, not measured.

An equally astonishing advance has been made in the oil production of
this rock within four counties of northwestern Ohio. Single wells drilled
during the last year have begun their production at a rate of 10,000 barrels

XII— Bum,. Geo:.. Soc. Am., Vol. 1, 1889. (80

E. ORTON — ROCK PRESSURE OF NATURAL GAS.

per day; and more than 200,000 barrels of total production are already to
be credited to single wells of the new field, while a considerable number
have passed the 100,000-barrel mark.

'I'm: Rock Pressure.

The rock pressure of the gas is a vital factor in all this production. To
its energy is due the propulsion of the volatile fuel from the wells where it
i- released, through twenty, thirty, fifty miles of buried pipes, to the cities
which it supplies with the unspeakable advantages of gaseous fuel. It is the
Bame cause that lifts the oil from the rock in all flowing wells.

By ruck pressure is meant the pressure which a gauge shows in a well
that is locked in after the drill has reached the gas reservoir. The iron
tubing of the well becomes by this means a pari of the reservoir, and the
Bame conditions as to pressure are supposed to pertain to it that arc found
in the porous rock helow.

The rock pressure of gas varies greatly in different fields and to a less,
but Still an important, extent indifferent portion- of the same field. The
highest rock pressure recorded in the Trenton limestone is about 650 pounds
to the square inch, while there are considerahle sections of the gas territory
that never reach 300 pounds pressure per square inch. The original pressure
in the Findlay field was 150 pounds, varying somewhat in wells of differenl
depths. In the Wood county field, from which the largest amount of gas is
now being conveyed to Ohio cities, the original pressure ranged from 120 to
lv'i pounds, the general pressure being counted 160 pounds to the square
inch. There were occasional records made of still higher pressure in single
well-, hut of such cases the number is very small, ami the existence of th
anomalous pressures was short-lived.

Passing to the westward, the gas wells of A.uglaize and Mercer counties
-how a decided reduction in original rock pressure as compared with Find-
lay, though the depths of the wells remain the Bame as in that lield. The
highest pressure recorded in Mercer county is :!!)(» pounds t.> the square
inch, but ii" gauge was applied to the wells until they had been allowed t ■ »
discharge without restrainl for several months, while 375 and 350 pound-
mark the extreme limit of Other portion- of this district.

In the Indiana field a >till further reduction of rock pressure is to he
noted. The range of the principal Indiana wells is between 250 and 325
pounds to the Bquare inch. The Indiana Lra- wells, as compared with Ohio

- wells, are marked by a reduction in total depth, a- well a- in rock
pressure, the figures for depth in the productive territory seldom or never
passing one t bousand feet.

II w can these variation- be accounted for? Back of this ipie.-tioii is a

larger one, viz: What ii the origin of the rock pressure of natural gas?

Theories of Origin of Kock Pressure.

Considering its importance, the main question has received less considera-
tion than would naturally be expected. The known literature of the subject
is very meagre. Professor J. P. Lesley, in the Annual Report of the Penn-
sylvania Survey for 1885, discussed the question at greater length than any
other geologist, so far as I know. In a paper published in the American
Manufacturer May 27, 1887, I threw out a few suggestions as to the cause
of rock pressure, and these suggestions I afterwards expanded into a more
extended statement, in the sixth volume of the Geology of Ohio, page 96.
Professor I. C. White reminds me that he suggested an explanation in the
journal named above at an earlier date than either of those given.

The men who are engaged in the practical development of gas and oil
fields make great account of rock pressure. It is the first fact that they
inquire after in a new gas field. They appreciate its importance in whatever
utilization of the gas they may propose, knowing that the distance of the
markets that they can reach and the size of the pipes that they can employ
are entirely dependent upon this element. These practical men, so called,
are, as is well known, among the most venturesome of theorists, and a ques-
tion like this would not be likely to be left unanswered by them. A certain
rough correspondence that exists between the depth and the rock pressure
of wells is made of great account in explanations that they offer. In other
words, the pressure is supposed to be due to the weight of the overlying
rocks ; and next to this we find among them the expansive force of gas the
favorite explanation of the phenomenon.

In the paper of Professor Lesley, already referred to, the learned author
suggests the two possible explanations of rock pressure already named, and
to this he adds a third, viz., hydraulic pressure ; but he adds this explanation
only to reject it as a true cause of the phenomenon under discussion. The
absurdity of the more commonly received explanation of rock pressure, as
due to the depth of the well— in other words to the weight of the overlying
country, — he sets in such clear light in his discussion that no further con-
sideration of this is required on the part of those who are open to reason.
Until we can prove, or at least render it probable, that the gas rocks have
lost their cohesion and that they exist at the depths of storage in a crushed
or comminuted state, no explanation can be based upon the weight of the
overlying rock in accounting for the force with which the gas escapes from
its reservoirs when they are penetrated by the drill. Professor Lesley throws
the whole weight of his authority in favor of the view that the gas "produces
its own pressure, like gas generated by chemical reaction iu a closed vessel."
This explanation certainly leaves something to be desired, for it fails to
-account for the most significant and important tacts in this connection, viz.,
the differences of rock pressure in different localities and at different depths-

(89)

90 E. ORTON — ROCK PRESSURE OF NATURAL '.As.

To accept it brings us no advantage whatever beyond the satisfaction that
we may feel in having an answer at hand that can be promptly given to a
troublesome inquiry.

in v own part. I have fell certain for more than two years that the
lock pressure of gas in the Trenton limestone of Ohio and Indiana is hydro-
static in origin, and I have published a number of facts that seem to me to
give Bupport to this view. 1 find that some sagacious operators in the new
and oil fields are coming to the same ground. They have become
thoroughly satisfied by their own experiences that the root of rock pressure
i- to be found in the water column that stands connected with the porous
rock in which the gas and oil are contained. In the present paper, I desire
to present to the < reological Society a few facts and conclusions hearing upon
the subject.

Thk Data fob the Hydrostatic Theory.

The first question is, What are the fact- as to the rock pressures of the gas
rock in question, and what relations do they hear to the depth of wells and
other condition- in the Trenton limestone? The answer is not as full and
definite as may be expected, certainly not as may be desired. There is but
one date in the development of a gas field in which the normal gas pressure
can he ascertained, and that is when the first well reaches the reservoir and
releases the long-imprisoned and greatly compressed gas. But often this
favorable opportunity is lost, and gauges are not applied to wells until the
energy of the first flow is somewhat abated. Again, different wells in the
-ame field, as Findlay for example, give different results. The wells vary
with the depth at which the gas rock is found. This factor is found to be
an essential one, as will presently be Bhown, in connection with rock pressure.
Moreover, gauges are sometimes inaccurate, and their errors come in to con-
fuse the Study of the subject. Furthermore, the exact depth of the wells
and the exact altitude of the surface where they are' located cannot be as-
certained in all cases. Small errors of this sort must be provided for. and

there also enters into the discussion a question as to the specific gravity of

the water which i.- to be made the moving force of gas ami oil. The water
found in association with these substances is never fresh. It is always saline,
and often highly mineralized. The weight of fresh water to the square inch
is 0.43285 pound lor one foot in heighl <I use Professor Lesley's tables).
The average weight "i sea water is 0.445 pound to the Bquare inch for one

foot ; but the mineral waters with which we find the Trenton limestone sat-
urated often reach a much higher figure. An examination of several speci-
men- -how- that a column one foot high would weigh to the square inch

0.476 pon ml. I n fact, some of these watu rs are more like bitterns, and their

column- would equal or 0.5 pound per foot.

THE TRENTON LIMESTONE As A GAS ROCK. 91

Bearing these several sources of ambiguity or uncertainty in mind, we can
consider the records of pressure, depth, and the other factors that are ac-
cessible. The figures as to pressure have already been summarized in a pre-
ceding paragraph, but they will be repeated in an accompanying tabular
statement. Before coming to this, however, let me in the briefest terms
review the conditions under which gas, oil, and salt water exist in the Tren-
ton limestone. The uppermost beds of the great Trenton formation in
northwestern Ohio, central and northern Indiana. Michigan, Illinois, and
Wisconsin consist of a porous dolomite, five, fifty, one hundred, or even one
hundred and fifty feet in thickness. Sometimes the dolomite is found in a
continuous body, but ofteuer in interrupted beds. This part of the formation
has outcrops in the Manitoulin islands of Lake Superior, and in the Galena
limestone of Illinois and Wisconsin. In the gas and oil fields, it is found lying
in terraces and monoclines, or flat arches, eight hundred to fifteen hundred
feet below the surface ; and these several features effect the separation of the
varied contents of the porous rock. The boundaries of gas, oil, and salt
water are easily determinable and are scrupulously maintained in the rock,
except that as soon as development begins the salt water is always the
aggressive and advaucing element. When the drill descends into the gas
rock proper, dry gas escapes ; when into the contiguous and lower-lying
terrace, oil accompanied with gas appears, as already described ; but at a
little lower level salt water is struck, and this rises promptly in the well,
sometimes to the point of overflow. Far out from the narrow ridges or
restricted terraces where gas and oil are found the salt water reigns undis-
turbed, and wherever reached by the drill it rises in the wells as in those
already described. It would be in the highest degree absurd to count the
little pockets of gas that are found in the arches the cause of the ascent of
this ocean of salt water a score or a hundred miles away. The rise of the
salt water is unmistakably artesian. It depends on hydrostatic pressure, as
does the flow of all artesian wells, and its head must be sought, as in other
like flows, in the higher portions of the stratum that are contiguous.

The nearest outcrops of this porous Trenton have been already named.
They arefouud in the shores of Lake Superior at an altitude of about six
hundred feet above tide. It is certainly significant that when an abundant
flow of salt water is struck in a boring in northern Ohio or in Indiana, no
matter at what depth, it rises generally about to the level of Lake Superior;
or, in other words, about six hundred feet above tide. If the mouth of the
well is below this level, as is the case in the Wabash valley, the salt water
overflows. On the shore of Lake Erie the water rises to within 20 feet of
the surface; in Findlay, to within 200 feet. The height to which the salt
water rises in any portion of the field is one of the elements to be used i n

K. ORTON — ROCK PRESSI RE OF NATURAL GAS.

measuring the force which cau be exerted on the gas and oil that are caught
in the traiis of the terraces and arches of the porous Trenton limestone.

Why, then, is nol the rock pressure of the gas the same in all portions of

the new horizon ? For the obvious reason, I reply, that there is a varying

element involved, viz., (he deplh of (he rock below sea level. The surface

elevations at the wells vary greatly, and the wells of the same depth con-

lently find the Lra- rock in very different relations to sea level.

Tin-: Test of the Btdrostatk Theory.

It is obvious that it' an explanation of the rock pressure of the Trenton
limestone gas is attempted on this basis, there are facts enough now at
command to substantiate or overthrow it. By the facts it must stand or
fall. In the accompanying table I have indicated the following lines of
facts as t" strictly representative wells in the leading districts of the new

- fields, viz: (1 ) location, (2) depth at which gas is found, (3) relation of
this depth to sea level, (4 i the initial rock pressure of the gas. In regard
to tin- last line of facts I have taken, in almost all cases, figures that I have
myself verified. (5) A fifth column I add, in which the pressure due in the
particular well is calculated from the two following elements, viz., an assumed
elevation of the salt water to the Lake Superior level, or six hundred feet
above tide; and, secondly, an assummed specific gravity of the salt water of
the Trenton of 1.1, which gives a weight of 0.476 pound to the foot.

Locations.

Ohio.
Tiffin, j

Loomie A: Nyman Well, i
l ' pper Sandusk j
Well No. 1. [ ••""

Bloom Tp W I I o

iend Well, j

Pindlav, )

Pioneer Well, j "

Si. Man
\ \\.

1 1
Dwyer Well, No. i

Indiana.

Kokomo, i

No. I. i

Marion, 1
W

M uncie .

Depth
Gas

1500

ft.

1280

l l l",

■

I L20

■•

I 159

l 156

Relation of <ci-
K'>ck to Sea
Level.

7 17 ft. below tide.

178

895 " "

386 " "

238 " "

200 " "

At till" level.

Original or
first Obser-
ved Press-
ure.

650? lbs.
515 "

in:, "
150 •■
890 "
876 "

820 "

828 "

, ■< ii

Calculated
Pressure.

l/=0.476

lb.

c,ll 11-.

513 "

173.6 ••

145.7 "

398.8 "
885 '•

:v::i "

wsir, ••

286 6 •'

HARMONY OF OBSERVATION AND CALCULATION. 93

These figures seem to me to settle the question as to the origin of the rock
pressure of the gas in this formation. I feel sure that nicer determinations
of the facts involved as to altitude and depth would bring a still closer
agreement between columns four and five. I will ask you to note in par-
ticular the facts as to the St. Mary's and the St. Henry's wells. They have
practically the same depth, 1159 and 1156 feet; but there is a difference of
thirty-eight feet in the depth of the gas rock with reference to sea level.
There is a corresponding difference in the rock pressure of fifteen pounds, as
recorded. The difference in rock pressure due to this thirty-eight feet by
calculation is 13.8 pounds, or practically fifteen pounds. I presume that
column five is as near the truth in this particular as column four. The
gauge would quite certainly be reported 385 pounds if it lacked but one or
two pounds of that number.

The Laws of Gas Production.

The laws of gas and oil production and accumulation are coming to light
more clearly in the flat country of Ohio and Indiana than they have ever
done among the hills and valleys of the older Alleghany fields. As it seems
to me, no more important deduction from the new districts has been reached
than the law now stated, viz., The rock pressure of Trenton limestone gas is due
to a salt-water column, measured from about six hundred feet above tide to the
level of the stratum which yields the gas. The column can be conveniently
counted as made up of two parts, viz., a fixed length of six hundred feet
added to the depth of the gas rock below tide.

If this explanation is accepted as satisfactory for Trenton limestone gas,
I venture to suggest that the fact will go a great ways toward rendering
probable a like explanation for rock pressure in all other gas fields ; but I
will not at the present time venture to extend it beyond the limits I have
named. I am aware of certain facts, or at least supposed facts, from the
older fields that seem difficult of explanation on this basis.

There are a few obvious inferences from this law to which I venture to
call your attention in closing this paper :

"J. There is no danger that the great gas reservoirs of to-day will "cave
in " or " blow up " after the gas is withdrawn from them. The gas will not
leave the porous rock until the salt water obliges it to leave by driving it
out and taking its place.

2. This doctrine lays the ax at the root of all the optimistic theories which
blossom out in every district where natural gas is discovered, and especially
among the real-estate operators of each new field, to the effect thai Nature
will not fail to perpetually maintain or perpetually renew the supplies which

'.t| ORTON — ROCK PRESSURE OF NATURA1 GAS.

we find so delightfully adapted to our i iforl and service. So tar as we are

concerned, il La certain that Nature has done about all that she is going to
do in thi> line. In her greal laboratory, a thousand year- are a- a single
day.

N doctri sould i more healthful influent n the communities

that are enjoying the inestimable advantages of the new fuel than this. If
it were at once accepted, it would add years t<> the duration of these precious
supplies "I' power. The ignoranl and reckless waste that is going on in the
new gas fields is lamentable. The worst of it cornea from city and village
corporations that are bringing the gas within their boundaries to give away
ti> manufacturers whom they can induce on these term- to locate among
them. To characterize the use of a million feet of natural gas a day, in a
single town, for burning common Wrick, tor example, or in calcining common

limestone, there i- a g 1 word at hand, viz., vandalism.

4. If this doctrine of the rock pressure of gas is the true one, the geolo-
ho have to deal with the Bubject and the communities that have found
a supply owe it to themselves to keep it prominently before the people, who
are especially interested. They may make themselves temporarily disagree-
able thereby, hut by just so far as they convince those that are interested,
they lengthen the life of the-' precious suppli

'I'h i. I >i elation "i <;.\- Supply.

Judging from the presenl indications, the Trenton limestone gas of Ohio
i- not likely to he long-lived. It seems entirely probable that the term of
it- further duration can !)'• stated within the limit- of numbers that are
expressed by a single digit. In considerable sections of the field, the salt
water is very aggressive. It requires a steadily increasing pressure on the
will- to hold it hack. In one district last year, one hundred and twenty-five

pounds pressure would keep the gas dry, while now two hundred pound- are

required for tin- Bame purpot

Then- i- likely t" be great disappointment in regard to what is called gas
territory. 'The pressure and volume of large areas are found to fail tog< tht r.
Wells draw their Bupplies Prom long distances. A farm, or even a mile-
s'pi tion, may be effectually drained of it- gas without a well being

drilled upon it.

Natural gas i- a very admirable product, hut its highest office, after all,

uld lie to prepare the way for something better than itself, viz.. artificial

fuel better, for the reason that while it furnishes all the intrinsic

natural gas, it will he free from tin- inevitable disadvantaj

of tres ocured in the way in which the stores of the great gas fields

[ ained.

Discussion.

Professor I. C. White: I can add but little to the admirable presenta-
tion by Professor Orton. My studies in the Pittsburgh region have long ago
confirmed the absolute proof which Professor Orton has just given us. I
stated as early as 1886, in an article on this subject, that in my view it was
due to artesian pressure. This idea was also adopted by Mr. Westiugliouse,
president of the largest gas company in the world, the one which supplies
Pittsburgh with natural gas. But siugularly enough, although president
of this great organization, and having this idea in his miud in regard to the
origin of the pressure of gas, his company made no attempt to shut in any
wells until 1887, simply because the superintendents were afraid that the
pressure developed when the wells were closed would blow up the casing.
Finally, when the subject of the great waste of natural gas was agitated in
the papers and in the legislature, the superintendent of the field operations
undertook to shut in a well. He piled around a derrick several tons of
stone, cemented it together, and prepared for a pressure of something like
two or three thousand pounds to the square inch. To his great surprise, the
pressure gradually went up to only 500 pounds. After that they very soon
shut in every well they had.

Now, although the rock that produces the gas in that region is a sand
instead of dolomitic limestone, as in Ohio, yet there is no reason to doubt
that it would show the same results Professor Orton has demonstrated. All
the data that I have collected goes to prove this statement. There is an in-
crease of pressure with the depth of the wells. The largest pressure that I
know of is 1,000 pounds to the square inch. This is in the valley of the
Ohio near Pittsburgh, and it took the well several hours to attain that press-
ure ; the depth was about 2,200 feet, and when proper calculations are
made from the point where that rock emerges from the Conemaugh river,
the pressure is sufficiently accounted for on artesian principles. The wells
in the Murraysville district are surrounded by what is called soda water,
which has the character of a bittern. It is not very salt, and some people
drink it as a mineral water ; but its specific gravity is very high. The first
well struck in Murraysville was allowed to play into the air for six years,
discharging 20,000,000 feet of gas daily, before any attempt was made to
utilize it; so that the original pressure of that field was probably never ob-
tained. The most reliable estimate ever made places it between 600 and
700 pounds to the square inch, which would be about what it should be
according to these calculations of artesian pressure.

The largest well I have ever known in the Pittsburgh region is one that
developed a pressure of 800 pounds in a minute. That well was sold lor
$100,000. This will give you some idea of the value of the gas, which, as

XIII— Bull. Geol. Soc. Am., Vol. 1, 1889.

9G l ORTON— ROCK PRESSURE OF NATURAJ GAS.

Professor Orton says, a practical man estimates according to the pressure it
will attain in a minute. In the region contiguous to AJleghany county and
Washington they have about five producing horizons. They are all porous
sand rocks, and there is an increase in pressure with the depth such as rep-
resented by I' ! Orton's figures; bo that, where it is possible to gel any
data with reference to these wells, they seem to amply confirm his statements.
Dr. A. C Lawson: 1 understand thai Professor Orton has suggested the
possible connection between the pressure of 600 feel of sail water and the level
■ it' Lake Superior. I would ask whether that figure represents a horizontal
plane in the earth's crust, or whether it has a slope from 600 feel down to

zero?

Professor Orton: So far as my observation goes, in Michigan. Indiana
and Ohio, the surface of the salt water is a horizontal plane. The water
doe.- not always rise promptly, but give it time and it rises to the level already
named. For example, a deep well has lately been drilled in Erie, Pennsyl-
vania, and salt water, apparently derived from the Trenton limestone, has
risen from a depth of about 3,000 feet to the lake level.

Dr. Lawson : I would like to ask the extent to which capillary attraction
in the rocks raises salt water in the column above the sea level ?

Professor Ortox : I would not presume to answer that, but this factor is
taken out of the account, from the presence of the impervious shale that
makes in all cases the cover of the gas rock or oil rock and that prevents
the a.-cent of the salt water; and it i> the penetration of this cover that
gives us our first ace-- to the gas, oil, and water that are contained in these
porous rocks.

Mr. W J McGee: A few months ago 1 had occasion to make a study of
the Indiana gas held. Fortunately I was acquainted with Professor Orton's
work in Ohio, and not only made use of the theory which he has so well
developed, but was able to fortifyit by a large number of observations (made
chiefly by a collaborator of the I . S. ' Seological Survey, I )r. A. .1. Phinnej
in my hands at thai time; so I can supplement Professor White's remarks
b\ Baying that this theory explains in a satisfactory manner the phenomena
displayed by all the gas fields of Indiana— those of the great central field
and those of tnosl of the .-mailer outlying fields as well.

I desire to add a more general tribute to the excellent work recorded in
Professor Orton's communication. In my judgment, the most important
advance .ver made in economically applied geology in a brief period was
that made within the last three years in the United States. Three years ago
k gas with all it< phenomena was a mystery t" the geologist a- well a- to
the layman, and the geologisl W unphl.lv in the dark a- the prospector

concerning the origin of tie mcerning the law- of its distribution, con-

ning the cause of the rock pressure, and concerning other important qui

THE LAWS OF DISTRIBUTION. 91

tions connected with it. But within the past three years the laws governing
the origin, distribution, and pressure of rock gas have become as well known
as are the laws governing artesian water supply ; so that today the
geologist prognosticates rock gas nearly if not quite as definitely and cer-
tainly as he prognosticates artesian water ; and it is only just to our associates
and to American science to say that this great advance in geologic science
was due almost wholly to two of our fellows — to Professor Orton, the author
of the communication before us, and to Professor White, who has already
spoken upon it. To these two men we are indebted for this unparalleled
stride in American geology. Others, indeed, contributed facts, but they
philosophy; and science was immeasurably enriched by their contribution.

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA

VOL. 1, PP. 99-162, PL. 2

NOTES ON THE SURFACE GEOLOGY OF ALASKA

ISRAEL C. RUSSELL

WASHINGTON
PUBLISHED BY THE SOCIETY
March, 1890

170

176"

180

17 0-

L70

SKETCH M

ROUTE TRAVELLED B^
Scale 1:10,

VOL. 1,1869, PL

150°

1 15

140

ia5°

150°

12,5"

155°

150°

145°

140"

130°

[f.S.Selden.D'-ot

1 OF ALASKA

.C.RUSSELL IN 1889
= 167 miles •• linch

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA
Vol. 1, pp. 99-162. pl. 2 March 13, 189o

NOTES ON THE SURFACE GEOLOGY OF ALASKA

BY ISRAEL C. RUSSELL

[Read before the Society, December 26, 1889)

CONTENTS

Page

Introduction 101

Nomenclature of the Yukon and its Tributaries 104

Geological Structure of the Y^ukon Region 108

Monoclinals 108

Faults 108

Joint-valleys -- 109

Bluffs on the Upper Yukon ' 109

Geology of the Yukon River HO

The Delta of the Yukon HO

General Character HO

Drift Timber 11°

Surface of the Delta m

The Banks of the Y'ukon u'2

Erosion of the Right Bank 1'-

Lower Ramparts H^

Lowlands 112

Highlands of the Upper Yukon 1H

The Water of the. Yukon 115

Muddy and Clear Tributaries H&

Sediment in Suspension H"

Geological Records now being made by the Yukon 116

The River in Winter nJJ

Spring Freshets *™

Rock Surfaces polished and scratched by River Ice 117

Bowlders transported by River Ice ]

Gravel Heaps deposited by River Ice ]

Pebbles faceted, polished and scratched by River Ice 119

"Bowlder Clay" deposited by Rivers

Old Deposits of ice-borne River Gravels

Flood-Plain Deposits _"

Mammoth Remains in the Banks of the YTukon I22

Extinction of the Mammoth

Preservation of Fish Remains '-

Navigation of the Yukon and its Tributaries v2i

XIV— Bum,. Geol. Soc. Am., Vol. 1,1889. *• '

l'i" I. C. RUSSELL URFACE GEOLOGY OF ALASKA.

Page

l i 125

logy of thi overed Shores of Alaska -_. 126

Definition 125

i I neral Characters 125

M de of Formation l-,;

A | — ible Origin of Coal Seams 127

tea "ii the Tundra l-s

Stratified Cce in the Tundra — 128

\| ■ ---. Covering of the W led Portion of Alaska 129

I l stribution of the Mossy Covering I-"-1

Depth of the Frozen Stratum beneath the .Muss 129

Depth of Frost in the Arctic 130

The Frozen Moss-layer as a Geological Agent — — 182

: Rocks 133

igraphical Distribution of Rock Decay 133

Absence of pronounced Bock Decay in Alaska 134

aparison with other Regions 134

Disintegration of Rocks 135

G g iphical Distribution of Rock Disintegration 135

Observations in Alaska 135

I I bris Streams 135

Talus Slopes or Screes 136

Absence of Debris in the Glaciated Region 136

Amount of Disintegration l;>7

Glaciation 137

Previous Explorations — 137

Personal Observations 138

Dnalaska 138

Absence of Glacial Records about St. Michaels 140

-ence of Glacial Records along the Yukon l'n

Absen f Glacial Records along the Porcupine ill

The Snow Line 141

Glaciation of the Upper Yukon Region ill

Previous Explorations 1 1 1

Upward Deflection of Glacial Grooves 142

Freshness of the Glacial Records 142

Bowlder Clay ... L48

Direction of Ice Movement 148

Northern Limit of Glaciation ill

I __. _. I II

earn Terraces along the Yukon i 1 1

Dust in Stream Terraces. L45

Plateau Ti 146

Lake Terrai ■ - 146

l i i on . . .. ... . 146

Previous 0 148

Position and 1. .. 146

D hown bj I NT

THE ROUTE EXPLORED. 101

Lake Yukon — P

Sediments 147

Origin of the Lake 147

Existing Glaciers 148

Observations at Chilkoot Pass and about Lynn Canal 148

Absence of Debris on the Glaciers : 15]

Fan -shaped Terminals 152

Recession of Glaciers about Lynn Canal 152

Distribution of Glaciers in Alaska and accompanying Climatic Con-
ditions 152

Discussion 155

Index . 157

Introduction.

In the spring of 1889, the U. S. Coast and Geodetic Survey organized
and equipped two parties in San Francisco, Cal., for the purpose of estab-
lishing the position of the boundary between Alaska and the North West
Territory of Canada. These parties were in charge of J. E. McGrath and
J. H. Turner, officers of that survey, and had for their destination localities
on the Yukon and Porcupine rivers respectively, where those streams cross
the 141st meridian.

Through the courtesy of the Superintendent of the U. S. Coast and Geo-
detic Survey, the Director of the U. S. Geological Survey was invited to
send a representative with the boundary survey parties for the purpose of
making geological observations in Alaska. This duty was assigned to me,
and a record of such observations as the character of the journey undertaken
enabled me to make is presented in the following pages.

The expedition sailed from San Francisco on the steamship "Bertha"
June 14, 1889, and reached Iliuliuk, Unalaska island, June 27. We re-
mained at Iliuliuk four days ; our effects having then been transferred to the
steamship "St. Paul", we sailed for St. Michaels June 30, and, crossing Beh-
ring* sea, reached there July 7. We remained there until July 14, when,
all arrangements for ascending the Yukon having been completed, the final
stage in our journey was begun. The ascent of the river was made in the
stern-wheeled steamboat "Yukon", belonging to the Alaska Commercial
Company and built especially for the navigation of the rivers of Alaska.

Our voyage up the Yukon was slow but did not allow much time on shore.
No stops were made except to obtain wood or provisions until arriving at
Fort Yukon, and such brief opportunities as were available for land excur-
sions were frequently at localities where geological exposures were poor.

We reached the site of Fort Yukon on August 2, and there landed Mr.

*S|.elled in four ways: "Bering," " Reering," " Behring," and " Bhering." The third hum has
the authority of the gazetteers, but the first is preferable and appears in the accompanying map, pi. 2.

L02 I. C. RUSSELL— 5URFACE GEOLOGY OF A.LASKA.

Mc( J rath and his parly for the purpose of making astronomical and magnetic
observations, while the Bteamboat proceeded nj) the Porcupine river with
Mr. Turner and bis party. I accompanied Mr. Turner to within about forty
miles of his destination : which was as far as the steamboat could go, owing
to low water in the river. < >n returning from the Porcupine river trip I
remained a Pew day.- at Fori Yukon, and then proceeded to Mr. McGrath's
Btation on the Yukon at the boundary, arriving there on August ID. I re-
mained with Mr. McGrath about a week, and then continued the ascent of
the Yukon, reaching the mouth of the Pelly river, the destination of the
" Yukon ", on August 31.

< >n arriving at Pelly river I made arrangements for continuing my journey
with a party of miners who were on their way from Forty-mile creek to
Juneau. We left the site of Fort Selkirk on September l,and "poled" and
" tracked " our open boat up the Yukon to the mouth of the Lewes, and then
ascended that stream, passing through lakes Lebarge, Tagish, Xares, and
Bennett to Lake Lindeman. From Lake Lindeman, which is at the head
of boal navigation, I crossed the Chilkoot pass on foot, and reached the
head of Taiya inlet, the extreme northern reach of Lynn canal, on October
]. From there I proceeded to Juneau in an open boat, and took passage in
the steamship "(i. W. Elder" for Port Townsend, and thence proceeded to
Washington, D. C, by rail.

Tie- time -pent in Alaska and the neighboring portion of the North \Vest
Territory, during which at least occasional opportunities for geological work
were afforded, was about three months. During that time I traveled by
Bteamboat, open boats, and on loot about twenty five hundred miles. Oppor-
tunities for geological work were thus necessarily very Limited.

The accompanying paper has been -prepared not with the hope of contrib-
uting largely to geological science, but because the observations relate to a
little known region and for that reason may have some interest. If the

paper - ther purpose than to direct the attention of future travelers

to certain questions of geological importance, I shall consider that it has
DOl been w ritien in vain.

Tie- route followed had been previously traversed by W. II. Dall from
Michael- to Fori Yukon, and by G. M. Dawson from the uth of the

Pelly river to Juneau. Since returning I have learned that previous to my

journey R. S. McConnell descended the Porcupine river to its mouth, and
then followed the same route to Juneau that was traversed by Dawson and

myself. An account of McConnell'8 explorations was read before the
American • ■■ - • i < t \ at it- New York meeting, in December, 1889,

and appears elsewhere in tin- volume. In the following page.- references will
frequently be made to the writings of the gentlemen jusl mentioned, and I
am pleased to say these will necessarily be in the direction of commendation.

SUGGESTIONS FOR FUTURE SURVEYS. 103

In order that these observations may be easy of reference they are arranged
under definite heads, as shown in the accompanying table of contents. All
references to the personal incidents of the journey have been omitted for the
reason that the trip was in no way an original exploration, so far as a
general knowledge of the region visited is concerned. In following this
course I may be doing an injustice to my companions and fellow-travelers,
to whom I am indebted in many ways, and especially to Messrs. McGrath
and Turner, who did all in their power to make the trip both pleasant and
profitable. While writing these pages my thoughts often revert to the
lonely snow-bound cabins in the far North, where my friends and comrades
of many weeks of interesting travel are keeping their vigils with the stars.

I am also indebted to the Alaska Commercial Company for allowing me
to accompany the expedition free of expense.

My companions in the arduous journey from Fort Selkirk to the head of
Lynn canal were Frederick Miller, Frank Cromier, Henry Lariviere, and
Joseph Beauchreau — all open-hearted frontiersmen of wide and varied ex-
perience, to whom I am indebted not only for personal assistance but for
much valuable information.

In closing I wish to call attention to two enterprises which might greatly
assist the development of the interior of Alaska.

The first is a survey of the Yukon delta, which would determine whether
there is a channel by which ocean-going vessels can enter the river.

The second is a survey of the passes between the head-waters of the Yukon
and the coast. This would furnish those interested in the development of
the country the needful data for making trails and wagon roads from the
sea-shore to the head-waters of the great river system of the interior. There
are four passes more or less practicable for this purpose, none of which have
been surveyed. Beginning with the easternmost, the first is the Taku pass.
It lies between the head of Taku inlet, just east of Juneau, and the head of
A-tlin lake, or the head of the Tako arm of Tagish lake. This is reported
to be a very low divide, too low in fact to be called a pass, and is thought
to be practicable for a wagon road. The second is White pass, leading from
Taiya inlet, at the head of Lynn canal, to the Tako arm of Tagish lake.
The third is the Chilkoot pass, already well known in a general way. The
fourth is the Chilkat pass, leading from the Chilkat inlet, at the head of
Lynn canal, to the head of the Tahk-heena river, which joins the Lewes a
few miles above Lake Lebarge.

So far as I can judge, the most practicable of these several routes, though
not the shortest, is the Taku pass. While there is reason to suppose that a
wagon road could be constructed on this route without great expense, there
is little doubt that the other routes mentioned are entirely impracticable for
the purpose. The White and Chilkoot passes are considered available for

lll| i. c. RUSSELL — SURFACE GEOLOGY OF ALASKA.

pack-train trails, and afford the most direct lines of c mmnication between

the navigable waters of the coast and the lakes and rivers of the interior.

Tli.' interior of Alaska is known to be of value on account of its deposits
of gold, copper, and coal, its fisheries and its furs. It is claimed also by
many uli<> are familiar with the region that it will ultimately be settled by
an agricultural people who are inured to the rigors of an arctic climate. It
ms, therefore, that the most practicable routes to the interior should be
made known at an early date, not only with the view of reducing the cost of
transportation, but also of decreasing the hardships and dangers attending
the crossing of the passes in their present condition.

V>MI \, LATUBE (>F THE YUKON RlVEE AM) ITS TRIBUTARIES.

In writing about the Yukon river and its tributaries, an unfortunate con-
fusion in nomenclature is met at the outset.

'lie- early exploration of the Yukon by Europeans was made in part by
Russians, who came from the west and ascended it from the sea; and in
part by members of the Hudson Bay Company, who came from the east and
explored and named some of the principal streams forming its head-waters.
When the connection of these various fragmentary explorations was estab-
lished, a confusion of names resulted.

Later travelers visiting the same region not only ignored the aboriginal
name- a- did their predeci — re, hut also refused in certain instances to
recognize well-established English and Russian names.

The history of discovery in central Alaska and the adjacent part of the
North West Territory ha- been recorded by W. II. Dall in his great work,
•• Alaska and it- Resources", and has recently been judiciously discussed by
( ;. M. I tawson. The thorough manner in which these writers have performed
their tasks render- ii unnecessary to discuss here the origin of the various

Dames proposed for the river of Alaska. It does appear desirable, however, to
determine what name- .-hall he used in this paper for tin; streams traversed,

and especially to decide to what stream the aame " Yukon " shall be applied.
Referring the reader to the writings of I>all and Dawson for a history of
the nomenclature of the great river of Alaska and its tributaries, attention
may he called to two authoritative examples of the present use of the name
Yukon.

The last edition of the general map of Alaska published by the I . S.
Coast and Geodetic Survey may he considered as a leading authority <>n
the nomenclature a- well a- on the positions of Alaskan rivers, Bince it em-
bodies the results of all explorations available at the time of its publication.

i. V w. I '., iiml adjacent northern portion "I
.iiimi ll I-;.. i v su : .iiu.i:i, Annual Report (new

Pari B, pp. i Ik i-i . i iii

NOMENCLATURE OF THE FUKON. 105

On the map referred to, the name Yukon is applied to the stream which flows
from Lake Lindeman — or, more precisely, from Crater lake, since Lieutenant
Schwatka's nomenclature for the river is followed — and after passing through
lakes Bennett, Tahko, Marsh, and Lebarge, is joined by the Pelly, Stewart,
and Porcupine rivers. From the junction with the Porcupine to the sea
there is, I believe, at present no duplication of names, the word Yukon being
in current use by all writers on the subject.

Dawson has shown, in his report already referred to, that the extension
of the name Yukon so as to include the stream flowing from Crater lake
does violence to the nomenclature proposed by early explorers, and, more-
over, does not conform to the geography of the region. As stated by
Dawson, and as I have learned also from other sources, Crater lake is not
the main source of the Yukon, but of one of its secondary branches.

In Dawson's report and on the maps accompanying it, choice among the
names proposed by various explorers has been controlled by precedence.
What is known as the Yukon on the U. S. Coast and Geodetic Survey map
referred to above is divided into three portious : From the sea to the mouth
of the Porcupine river the name Yukon is retained ; from the mouth of the
Porcupine to the mouth of the Upper Pelly it is called the " Pelly" ; thence
to Tagish lake it is the " Lewes." The main source of the Lewes is considered
to be the stream which enters the Tahko arm of Tagish lake, while the stream
from Crater lake, flowing through Lake Lindeman, is a secondary branch.

As the streams concerning which there is a duplication of names are
chiefly in Canadian territory, I was strongly inclined to follow the usage of
Canadian geologists and explorers; but in attempting to do so, the incon-
venience of their system, as well as its disregard of geographical conditions,
forced me to reject it.

In topographic nomenclature account should doubtlessly be taken of the
names proposed by early explorers. The exclusive use of this system,
however, not only tends to confusion, but often entails an unnecessary burden
on writers and students of geography. The exploration of the Yukon
drainage system is yet far from complete, and we still have it in our power
to so adjust the names applied to it as to make them conform to geographical
conditions and yet not do geat injustice to the work of early explorers.

To one ascending the Yukon from the sea it is evident that no change of
name should logically occur where the main stream is joined by the Porcu-
pine, as there is no perceptible change in its character at that locality. The
same is true when the mouths of Stewart river and Pelly river are reached.
Continuing to ascend the main stream above the mouth of the Pelly, one
arrives, after voyaging about 150 miles, at the mouth of the " Tes-lin-too,"
as it is named on many maps* This stream, in my judgment, is in reality

Vfhis is the "Hootalinkvva " of miners, and the " Newberry river" of Sehwatka.

106 I. C. RUSSELL DRPACE GEOLOGY OF \I..\sK.\.

the continuation of the Yukon and should share its name. It flows through
a continuation of the same orographic valley that is occupied by the Yukon
(or " Lewes " i below its mouth, while the Yukon (of the U. 8. Coast Survey
map) or the Lewes (of Dawson's map) above the junction is but a tributary
stream, coursing through a narrow and poorly defined valley nearly at right
angles to the main line of drainage.

The fact that the so-called Tes-lin-too occupies a continuation of the Yukon
(Lewes) valley proper has been clearly recognized by Dawson, as is shown
by the following quotation :

"The valley near the mouth of the Tes-lin-too is again narrower than usual,
Bingularly so for the point of confluence of two important rivers. The valley of the
Tes-lin-too is evidently the main orographic depression which continues that occupied
by the Lewes below the confluence. The Lewes flows in through a narrow gap,
closely bordered by high hills and nearly at right angles to the lower course of the
river. On the map accompanying Lieut. Schwatka's report, the width of the
Tes-lin-too is shown as about half that of the Lewes, the actual fact being precisely the
reverse and all the main features of the lower river being contained by the Tes-lin-too ;
while the ether branch, both in its irregular mode of entry, the nature of its banks,
the color of it- water and its very rapid current, presents, at first sight, all the
appearance of a tributary stream of new character. To such an extent is this differ-
ence ohservable, thai Mr. Ogilvie and the members of bis party, as well as most of the
miners on the river, were of the opinion that the Tes-lin-too actually carries much
the greater volume of water. As this appeared to be a question of some importance,
we -topped a day at the confluence for the purpose of investigating it, cross-section-
ing each river and ascertaining the rate of the current at distances of about half a
mile from the junction, where the circumstances were favorable. It was thus ascer-
tained that the rivers possess the following dimensions: —

/.• iocs. '/'■ -I'm-too.

Me:,n width 420 feet. 575 feet.

Maximum depth (near left bank). _ 12 " (near right hank) 18 feet 4 in.

Sectional area 3,015 -; 3,809 feet.

Maximum velocity 5.68 miles pr. hr. 2.88 miles pr.hr.

Discharge per second 18,664 cubic feet. 11,436 cubic feet.

•• In connection with these measurements it may be stated that the Lewes showed
evidence of having risen about a foot above its lowest summer level, while the Tes-
lin-too was probably near its lowest summer stage. (All the rivers in this country

reach their actual minimum toward tl nd of the winter.) I fwe Bubtrad the volume

water represented by this extra foot in depth, the discharge ofthe Lewes at the
summer low-water .stage may be approximately stated at 15,600 cubic feet."*

The secondary character of the stream draining Lake Lebarge where it
joins the " Tes-lin-too " is indicated by the fact thai a party of miners who
had descended from Lake Lindeman to Forty-mile creek, and tnighl there-

Yiik.,ii District, lOC. 'II., !•■ L53b.

THE MAIN YUKON RIVER. 107

fore be supposed to have some idea of the drainage system, iu attempting to
return, passed its mouth and ascended the main stream for over fifty miles
before discovering their mistake. My observations while at the junction of
the rivers just referred to confirm what Dawson has written concerning that
locality. It seems evident to me that no unprejudiced observer could
examine the junction without concluding that the " Tes-lin-too " should be
regarded the main drainage channel.

In this paper the nomenclature adopted by Dawson will be followed so
far as it accords with the geographical conditions. The name Yukon will
be applied to the main trunk of the drainage system now under discussion
from its mouth to its source, the source being in the as yet unexplored region
draining into LakeTeslin. The name Lewes will be retained for the stream
on which Lake Lebarge and the numerous lakes higher up in the same sys-
tem are situated. The main source of this stream, as stated by Dawson, is
unquestionably to the southeast of the Tako arm of Tagish lake, but like the
source of the Yukon it awaits exploration. A branch of the Lewes has its
source in Crater lake and is the route now usually followed by persons enter-
ing the Yukon region from Juneau.

When the lake region drained by the Lewes is fully explored, and espe-
cially when it becomes popular among summer tourists — an event perhaps
not very remote — the separate reaches of the river connecting the various
lakes will for convenience probably receive individual names.

Before dismissing this subject, attention may be called to the fact that
Dawson, who is the only authority on the geography and geology of the
Yukon district of the North West Territory, regards the main source of the
Yukon to be the Lewes. The reasons for this conclusion are stated in part
in the quotation given on page 106, and in part in other portions of his report.
On page 16 B he says : " Whether reckoned by size or distance from its
mouth, the source of the Lewes must be placed at the head-waters of the
Hotilinqu river;" and in a foot-note on the same page: ' The Tes-lin-too
occupies the main orographic valley above its confluence with the Lewes,
but is smaller than the Lewes, and besides doubles back on its course, as is
shown on the map."

The measurements made by Dawson place the discharge of the Lewes at
15,600, and of the " Tes-lin-too " at 11,436 cubic feet per second. Volume, so
far as shown by this single measurement, is in favor of the Lewes. This
circumstance is more than counterbalanced, however, in my opinion, by the
character of the channels or valleys of the streams in question. The main
orographic valley is occupied by the " Tes-lin-too," and there is no note-
worthy change in its configuration where it receives the stream flowing from

Lake Lebarge.

Dawson's statement that the source of the Lewes is more distant from the

X V-Kri.i.. Geol. Soc. Am., Vol. 1, 1889.

L08 I. C. RUSSELL [JRFACE GEOLOGY OF ALASKA.

. than the source of the " Tes-1 in -too " seems premature, as neither of these
streams has been fully explored, and their sources are unknown.

In view of the facts jus! stated, it seems to me advisable to apply the name
Yukon to the main trunk of the drainage system, commonly known by that
name in the lower part of its course — that is, that the Yukon, the JYlly, the
Lewes below the mouth of the Tes-lin-too, ami the Tes-lin-too to its source,
a- designated by Dawson, he named the Yukon.

Geologn \i. Structure of the Yukon Region.

Monoclinals. — The prevailing trend of* the mountains and the strike of the
lock- throughout the Yukon region below the mouth of the Porcupine is, in

teral, northeast and southwest. Along the Yukon, near the 141st meridian
and in the neighboring part of the North West Territory, the trend of the
main ranges is nearly east and west. Throughout the Yukon region in
Alaska the geological structure approaches that of the Great Basin of the
western United States. Nothing similar to the folds of the Appalachians or
the Alps has been observed in that region. The mountains are, in large
part, monoclinal ridges, hut do not reveal their structure as definitely as do
the ranges of Nevada and Utah. The presence of faults along the borders
of the upheaved orographic block can he readily determined, however, in
many instances.

Faults. — The finest example of monoclinal structure seen in ascending the
Yukon, though on a comparatively small scale, was in cliffs of sandstone and
Blate bordering the light hank of the river for several miles, at a locality
some fifteen or twenty miles below the mouth of the Meloikakat, or midway
between Nulato and Nowikakat. These sandstones contain the haves of
deciduous tree- and belong to the same system as the rocks at Nulato, which
have been di scribed by Dall.*

The river hank at the locality referred to is extremely precipitous, and
ezp08( - a fine Bection of the rocks, which dip. in general, northwest 25° to ''0°,
• jit where disturbed by faults. The displacement- trend nearly moth
and ,-oiith and appear in the cliffs as in a diagram. In the he.-t exposed
portion of the section there are six or eight important faults within a .-pace
ofaboui two mile.-. These are parallel and head to the easl at angle- ranging

from 25 t" I" . Iii each instance the strata are disturbed on approaching

the breaks, but BOOH return to their normal dip. At each fault a lateral

valhy ha- been excavated, the wesl side of which is a smooth, even, rock
-lope, frequently Blickensided, ami is in reality the heaved Bide of the fault.
The easl wall of each of the valhy- i- rugged and broken, and the Btrata in
the projecting ledges usually show a high dip towards the east. In other

\ ol. 16, 1868, pp. B7

INFLUENCE OF JOINTS ON EROSION. 1(1!!

ravines, where the structure was not clearly visible, the peculiar topo-
graphic conditions indicated a similar origin. These faults are instructive for
the reason that they illustrate the manner in which a series of displaced
blocks sometimes present a nearly uniform dip, so as to appear as a single
monoclinal when the exposures are not sufficient to show the true structure.

Joint-valleys. — The rocks in the precipitous bluffs of the Yukon exhibit a
pronounced jointed structure in many localities. As in other regions, the joints
occur in systems which cross each other at various angles. Their influence
on topography is sometimes plainly traceable not only in the pyramidal form
of rocky pinnacles, but in the contour of the valleys which separate them.
In a number of instances two main systems of joints exist which at their in-
tersection with a horizontal plane form parallel lines, but are so inclined as
to meet below the surface at an angle of twenty or thirty degrees. When
this occurs the prism of rock bounded by the joint planes and the surface of
the land has sometimes been eroded out, leaving a sharply defined V-shaped
valley of low grade. When so situated as to open in the tops of high bluffs
along the Yukon, these valleys discharge their water in cascades into the
river below.

The origin of certain low-grade lateral valleys iu the glaciated portion of
the High Sierra of California, which open high up in the bluffs bordering
larger valleys and discharge their waters in cascades, has never been satis-
factorily explained. The fact that similar valleys in a non-glaciated region
have resulted from the weathering of jointed rocks may help to account for
these peculiar topographic forms. Should the joint-valleys along the Yukon
be occupied by local glaciers their forms would be modified principally by
a broadening of their bottoms, and they would resemble still more closely
the smaller of the high lateral valleys of glaciated mountains.

Bluffs on the Upper Yukon.— The most remarkable bluff on the Yukon is
about twenty-five to thirty miles west of the international boundary, on the
left bank of the stream. This is a sheer precipice of contorted slate, about
600 feet high and more than a mile in length. The beds are seldom more
than a few inches thick, and composed of black, somewhat metamorphosed
slates, separated by yellowish-white layers. The strata are much contorted
and broken by small faults, along which a peculiar crumpling of the slate
has occurred. The general dip is toward the west. The cliffs terminate
abruptly at the east end, where they are cut off by a bold scarp trending at
right angles to the river. This scarp is mostly bare of vegetation, trends
N. 60° E., and slopes east at an angle of about 60°. It is really a fault-
face of so recent origin that it is not vet covered with vegetation. The steep
slope of the fault scarp has a pinkish color, seemingly due to debris of cer-
tain red rocks which, when undisturbed, occur above the contorted strata.

The series of contorted slates forming the great bluff mentioned may be

110 I. (. RUSSELL 1 RFACE GEOLOGY OF ALASKA.

seen for several miles along the river, both above and below it. They were
observed also on the Porcupine river, nearly due north of the locality here
mentioned.

[mmediately at the international boundary there are bold bluffs on each
Bide of the river, with mountains about 3,000 feet high rising hack of them.
The ranges are serrate, trend nearly east and west, ami are composed of
limestone in nearly vertical strata. The river follows the south base of one
of these limestone mountains for fully fifty miles east of the boundary. As
i from the river, this range seemed to be monoclinal in structure.

Near Forty-mile creek, and from there a long way up-stream, the banks
are in general of metamorphic schist with quartz veins. The rocks form
bold pinnacles and headlands along the river, leaving no room for a flood-
plain at their bases.

My notes on the rocks of this region are meagre, owing to the lack of
opportunities for personal examination on shore, aud I have withheld much
that I Hotel concerning the " hard geology," fearing that my hasty observa-
tion- might be too much in error to be of value.

■-

Geology of the Yukon River.

the delta of the fukon.

(,■ ieral C'ltarnctrr. — The delta of* the Yukon, as shown by such examina-
tions as have been made, is about L25 miles in length, the apex being where
the river first divides on approaching its mouth. The periphery of the
delta, n >t including minor sinuosities of the shore-line, is approximately 150
miles. This embraces, however, some highlands, which rise like islands in
the broad, nearly level expanse of sediment that has been spread out by the
river.

I fire! saw the delta near the entrance to the Aphoon branch. This is
the most northerly channel by which the Yukon discharges into the sea.
The land is there low and swampy, and iutersected by muddy sloughs and
tide-waye li is bare of trees, but covered by a most luxuriant growth of
mosses aud lichens. The meadow-like expanse is dotted everywhere with
ponds ami lakeht.-. This i> a pail of the -real tundra bell that skirts the
entire northern and western Bhorea of Alaska, the characteristic features of
w hieh : ■ i il» d i l.-i w here in this paper.

Drift Timber. The border of the delta and the hanks of the numerous
water channels thai intersect itare fringed with drift-wood. Debris of similar
character i- exposed in such abundance in freshly formed river escarpments

to i ■• no .dent thai the cut ire delta contains a more or less continuous

Bubstratum of trunks, branches aud roots of trees, embedded in river >ilt.

DRIFT-WOOD ON THE YUKON AND IN BEHRING SEA. 111

Above the timber layer there is a deposit of silt or clay, and covering this
is the peaty layer of the tundra.

While ascending the Yukon many trees and portions of trees were seen
drifting with the current, or stranded on the banks of the river, especially
on the upper ends of low islands, and where sloughs leave the main river.
At such localities there is not infrequently an acre or two of weather-beaten
drift-logs, piled together in a most confused manner and having a depth, by
estimate, of fully twenty feet in some instances. The banks of the Yukon
and of its tributaries are densely forested, and as they ai'e cut away by the
swift currents, furnish an unlimited supply of timber for the river to trans-
port.

The abundance of drift-wood along the banks of the Yukon or traveling
with its current explains the source of the many derelicts of the land ob-
served during the voyage from Unalaska to St. Michaels. The most of the
abundant drift-wood of Behringsea is undoubtedly derived from the Yukon
and Kuskokwim rivers. The shores of Behring sea are treeless throughout,
but are almost everywhere fringed with drift-wood. The wood thrown ashore
by the waves furnishes the only supply of fuel and building material for
the natives at widely separated localities, both on the mainland and on
numerous islands. At St. Michaels the supply of wood for fuel, both for
the residents and for the small steamboats, is gathered from the beach. A
large part of the fire-wood used on the steamboats which navigate the Yukon
is cut from drift timber. In the sediments now being spread over the bottom
of Behriug sea, water-logged drift-wood, principally spruce, must be of
frequent occurrence.

Surface of the Delta. — About forty miles up the river I made a short ex-
cursion inland and had an instructive view of a typical portion of the delta.
The immediate bank of the river at this point was low and swampy and
clothed with a dense growth of alders. The fringe of brush was half a mile
broad and terminated landward against a bluff about thirty feet high.
Ascending the bluff, I had before me a seemingly boundless expanse of moss-
covered land, without a tree or conspicuous shrub to relieve its monotony.
Here and there on the dreary moorland were lakelets, frequently circular in
outline and surrounded by flowery banks of moss. The soil beneath the
thick brown-green carpet was a dark humus, formed entirely from the decay
of the tundra plants. The thickness of the humus layer was not determined ;
below the depth of about a foot it was solidly frozen.

The conditions here briefly described continue to characterize the land
bordering the Yukon on either hand for a distance of sixty or seventy miles
from its mouth. On the right bank the inland border of the tundra is
reached a few miles below the village of Andreieflski. The land there rh
into hills and the spruce forest begins. The soil is a stiff clay, probably a
continuation of the substratum of the tundra.

112 I. i. RUSSELL URFACE GEOLOGY OF ALASKA.

At Andreiefiski the river, or rather the Aphoon branch of it, is nearly

> miles broad, and, as is usual throughout the lower Yukon, is cutting its

jht hank. The difference between high and low water is about live feet.

Throughout the portion of the Yukon delta that I saw, hut which must be

:haracteristic of its entire extent, there are many abandoned channels and

ild water-ways, some of which contain lakelets. The greater part of the

akelets on the tundra, however, originated in other ways. See page — .

The abandoned channel.- .-how that the stream is unstable and subject to

many changes. This is also known from the experience of the steamboat

captains, who have been familiar with the region for many years.

THE HANKS OF THE tfUKON.

Erosion oftht Right Bank. — After entering the Yukon river proper — that
i-. after passing the head of the first or highest branch which meanders
through the delta — the right bank is usually high and bold, while the left
bank is commonly bordered by lowlands. The fact that the Yukon through-
out the lower portion of its course is cutting its right bank has been men-
tioned by Dall and others and need not be discussed farther at this time.

The right bank is frequently bold and rocky, and at times forms palisades,
all the way from the head of the delta to the Koyukuk, about twenty miles
above Nulato. Above that point the river Hows through broad, swampy low-
lands for seventy or eighty miles, and then the Lower Ramparts begin ; both
banks become higher ami frequently form bluffs and headlands of great
beauty.

Lower L''iu>/>>irls. — In the Lower Ramparts there are high lands on each
side of the river. The stream is greatly reduced in width, is without islands,
and flows swiftly. The scenery is wild and picturesque, but scarcely more
impressive than the Highlands of the Hudson.

Lowlands. — Above the Lower Ramparts for a distance of about 250 miles
the Yukon flows through a low. densely wooded region, which is frequently
Bwampy and widely overflowed during spring freshets. The river spreads
out into many branches, which unite and divide so a- to enclose thousands
of islands.

The breadth <>t the lowlands on each side of the stream is unknown, but
in ascending the river the bordering highlands were frequently so distant
thai they could not !>• Been from the steamboat's deck. The conditions jusl
d< scribed extend for fully one hundred mile- up the Porcupine river. This
river, however, does not divide so a- to enclose islands, but forms a Bingle

. tortuous channel where it cuts it- way through the lowlands.

The great flatlande jusl described are of interest, as they indicate recent
chaugea in tie aphy of tie region. Everywhere through them there

abandoned stream channels, showing thai probably the entire region

ORIGIN OF THE LOWLANDS OF THE YUKON. US

including the numerous islands as well as the bordering country for many
miles, has been traversed by the river and is, in fact, a vast flood-plain
deposit.

The sections referred to in the newly eroded banks show current-bedded
gravels and sands, with occasional interstratified layers of peat similar to
that now forming the surface layer beneath the forest.

On looking down on the lowlands from hills near their border — the best
view that I obtained was from the summit of a hill about one hundred miles
up the Porcupine — one sees winding lanes opening out through the forest,
carpeted with bright green Equisetums, and overshadowed by tall spruce
trees or slim, gracefully bending willows. These picturesque lanes mark the
positions of recently abandoned water-courses. The most recent of these
old channels still hold ponds and sloughs, about which the moss grows with
great luxuriance. Those of older date are indicated by a change of tint or
a variation in the luxuriance of the forest trees, and may be easily recog-
nized in a wide-reaching view.

The vegetation on the lowlands is composed mainly of spruce trees, grow-
ing close together and attaining a height of sixty or seventy feet or more.
Along the stream willows and alders are common, and wild roses bloom in
luxuriance in all. of the more open spaces. Beneath the trees and dense
undergrowth there is a thick, soft carpet of lichens and mosses, in which
thousands of lovely flowering plants unfold their blossoms and ripen their
brilliant fruits. Beneath the moss there is usually a layer of vegetable
mould or peat, ranging from a foot or two to many feet in thickness. Its
maximum depth is unknown. Beneath the immediate surface the peaty layer
is frozen throughout the year. It rests either on strata of loose material,
as sand or clay, or immediately on the subjacent solid rock. The dense
forest of spruce rising above the moss is about all that distinguishes the low
swamp lands along the Yukon from the tundra of the coast. There are dif-
ferences, however, in the luxuriant, cryptogamic floras of the two regions,
which are sufficiently obvious on close examination.

The undermined and crumbling banks of the Yukon and tributary streams,
where they flow through the swampy lowlands, frequently exhibit sections of
ancient peaty layers, which are solidly frozen, and also the edges of strata of
clear ice. The trees growing on the undermined banks frequently lean far
over and dip their tops in the current before being finally carried away. At
times large blocks of the bank cave off and carry a number of trees bodily
into the river, where they sometimes remain standing half submerged for a
whole season. These slides are usually preceded by a crevassing of the bank
in lines parallel with its edge and distant some twenty or thirty feet from it.
The carpet of moss and rootlets that occurs throughout the lowlands, and,
we' might say without exaggeration, throughout Alaska, is so tenaceous and

Ill l.C. RUSSELL — SURPAC1 GEOLOGY OF ALASKA.

- closely woven thai when the river borders are washed away it hangs from
the top of the bank like a curtain, as if intended to hide the ruin the waters
had made.

The gn atesl expanse of the Yukon lowlands, as already mentioned, occurs
just above the Lower Ramparts, and extends some 250 miles to the eastward ;
ii- breadth may be roughly estimated at from 75 to ltti) miles. At the
Lower Ramparts the river is greatly contracted, and is now deepening its
channel. The explanation of the presence of the lowlands above the Lower
Ramparts seems to be that orographic movement is taking place, and a
mountain range is being raised athwart the river. Above the obstruction
the river has Bpread out a broad Hood-plain, through which it meanders.
This is only a suggested explanation of the origin of the lowlands. No
opportunity was afforded for studying the matter in detail. It is possible
that a broad lake has existed above the Lower Ramparts, but no beach lines
were observed on the hills which would have formed the border of such a
lake, and besides, the material exposed in the river hanks does not suggest
the presence of lacustral conditions duringits deposition. The lack of evi-
dence of the former presence of a lake, as well as the positive evidence of

tl 1-plain conditions, leads me to suppose that obstruction of the drainage

by orographic movement would account for all the conditions noted.

Whither a similar relation of lowlands to river narrows occurs in the
case of the swampy areas below the Lower Ramparts or not is uncertain.
The broad, moss-covered region of the delta belongs to another category and
mid m»t be considered in this connection.

Highlands of the Upper Yukon. — Above the lowlands through which the
Yukon and Porcupine rivers flow near their junction, the banks of the
Yukon are bold, and usually rise abruptly from the river. Many of them
rise like Bea-cliffs directly from the water's edge to a height of four or five
hundred feet, and can not be passed even by a person on foot. About their
bases the river sweeps with such force that the ascent of the stream in a
-mall boat i- exceedingly difficult.

A- one continue- to ascend, the terraces on the borders of the stream be-
come more and more prominent, until near the mouth of the IVllv river,

and thence to the lakes on the Lewes they form an important element in the
landscape.

At the mouth of the Telly, and for several miles below, there is a bold
palisade on the righl bank, formed by a basaltic escarpmenl Bome three or
four hundred feet high. This is the edge of a table land, formed by a lava
Mow which filled the valley and extended Beveral miles up the Telly. The
Yukon in excavating its channel occupied the Ii f junction between the

lava coulee and the bold left bank of its former valley. The Tcllv also

followed the border "I the coulee along it- eastern edge.
At the international boundary the Yukon flows through an exceedingly

tNFLUENCE OF GLACIERS ON THE YUKON. 115

rugged country, in which the mountains, composed largely of limestone,
trend nearly east and west, and are exceedingly sharp and rugged. The
river here flows with the strike of the rocks, but yet has only a very limited
amount of low land along its border. Near the mouth of Forty-mile creek
and for a long distance above, the rocks are a metamorphic schist, which
form bold rugged cliffs along the river, and afford some of the finest scenery
on the Yukon.

At the mouth of the Lewes the country is more open ; the hills are bold,
with rounded summits, and the characteristics of a glaciated region replace
the angular mountain forms so typical of the Lower Yukon country. About
Lake Lebarge, especially, the rouuded, flowing outlines of the hills bear
unmistakable evidence of intense glaciation. In ascending the Lewes the
scenery increases in grandeur until the snow-covered summits of mountains
along the southern coast of Alaska come in view. The many lakes of this
region add an attractive feature to the scene and enhance the maguificence
of the mountains surrounding them.

THE WATER OF THE YUKON.

Muddy and Clear Tributaries. — The larger streams tributary to the Yukon
and to the Lewes from the south — viz., the Tananah, White, and Tahk-heena
rivers — are heavily loaded with silt and have all of the characteristics of
glacial streams. All of the tributaries of the Yukon from the north, and also
the smaller streams from the south, are clear; but some of them arc dark
with organic matter derived from the swamps and moss-covei'ed areas through
which they flow. These characteristics of its tributaries indicate at once,
and the conclusion is sustaiued by other evidence, that all of the glaciers
within the Yukon drainage system are located along its southern border.

The Yukon below the mouth of the Tananah is intensely muddy, and de-
rives a very large part of its sediment from that river. Above the mouth of
the Tananah it is still very turbid, and holds this character to where White
river empties in its heavily loaded flood. Above that point it is practically
a clear stream, but still has a slight milky turbidity, which gives its water a
milky or opalescent tint. This slight discoloration is due to sediment con-
tributed by the Lewes. At the junction of the Yukon and the Lewes a
marked contrast in the color of the two streams is especially noticeable. The
Yukon above the junction is clear and dark, while the Lew- is decidedly
milky in appearance. This contrast has been noted by Dawson,- who ob-
serves : " The water of the Lewes has a blue, slightly opalescent color, much
resembling that of the Khone where it issues from the lake of < reneva, while
that of the Tes-lin-too [Yukon] is brownish and somewhat turbid."

* Rep. Yukon District, loc. cit., i>. i 53b.
XVI— Bull. Gbol. Soc. Am., Vol. 1, 1889.

L16 I. C. RUSSELL URFACE GEOLOGY OF ALASKA.

The principal Bource of the fine sediment that discolors the Lewes below
Lake Lebarge is derived from the Tahk-heena river, which has its source
among the glaciers near the Ghilkat pass and joins tin- Lewes just above
Lake Lebarge. The extreme fineness of the sedimenl which discolors the
waters of Lake L barge and of the streams flowing from it will be appreciated
when it is remembered thai although the lake is nearly thirty miles long the
water- passing through it are m>t completely cleared by sedimentation.

The waters of the numerous lakes along the course of the Lewes above

Lake Lebarge are also i e or Less turbid with silt. Their turbidity

increas ae approaches the Coast Range, on which are many glaciers,

and it is evident that the sediment in the lakes and streams is due directly
to the abrasion of the rocks by glacial ice. The water- of Lake Lindeman,
especially, are densely turbid and have a greenish-white color. The upper
portion of Lake Bennett is similarly discolored. As these water.- passdown
through lake- Tagish and Marsh they become greatly clarified, but still
retain suffici< nl line silt to reveal their glacial origin.

v ■mi' at in Suspension. — While ascending the lower Yukon five samples
of the water of the river, of a liter each, were collected at the localities given
below, and the weight of sediment they contained determined. The results
of this investigation are as follows :

Sediment in the Water of the Yukon.

Locality. Date. < ■ n a liter.
Below mouth of j^°\kf - ™y S' l889 &«f»

I Nowikakat.. .__. " Jo, " o. , 83

ive mouth of f Entrance of Lower Ramparts. " 27, " 0.2754

theTananah. \ Five miles above Lower fiamparts " 28, " 0.2078

No determination of the volume of the Yukon was practicable during my
journey, but it is expected that Messrs. McGrathand Turner will make such
measurements during their descenl of the river in 1890. When the results
of their observations are known, the data given above will enable one to form
a rough estimate of the amount of material that is being carried in suspension
from the land to the sea by Alaska's greal river.

•LOGICAL Rl NOW BEING MADE Bl THE iTJKON.

Thi I: in Winter. My experience on the Yukon is limited to a brief
summer trip. For information concerning it- behavior in winter I am
indebted to many miners and trader-, mid especially to Arthur Harper*
who has passed many winter- in central Alaska and the adjacent portion of
the North \\> -i Territory.

Like many norl h\\ ard-llowing river-, the ^ ukon i- closed by ICC firsl at

RECORDS MADE BY RIVER ICE. 117

its mouth, and in the spring opens first at its head. Near its mouth it is
closed each year about the middle of October, but has been known to remain
open as late as the first of December. As winter approaches, ice forms along
its sides, leaving open water in mid-channel or where the current is swiftest.
The fringe of ice first formed is smooth, and can be easily traversed. As
the river falls, however, during the winter, it becomes much broken, and in
many instances quite impassable. When the cold is sufficiently intense to
completely close the river mouth, the swift current packs the new slush-ice,
and cakes broken from the sides, against this ice bridge. This process con-
tinues progressively up-stream till the river is completely ice-covered from
mouth to source. The freezing of the lakes on the upper waters of the
Yukon, I have been informed, is frequently delayed until December.

From the manner in which the swifter portions of the river become ice-
covered, as well as from the breaking and subsidence of the ice due to the
shrinking of the river in very cold weather, the frozen river is almost always
rough and difficult to travel over.*

The thickness of the ice on the lower river is stated by several residents
to be generally from ten to fifteen feet. Some of the tributaries of the
Yukon, which are veritable rivers in summer, are frozen solid to the bottom
during winter. In Forty-mile creek placer mining is carried on in winter
by cutting away the ice and thawing out the frozen gravel beneath by means
of large fires. The auriferous gravel is removed to the bank of the stream
and washed when warm weather returns.

Spring Freshets. — In spring the river thawing first at its head frequently
initiates floods and ice gorges of great magnitude. At times the water behind
an ice dam rises thirty or forty feet, and if the bank of the river chances to
be low, inundates large areas. During these freshets immense quantities of
ice are borne along by the swift current and lodged in heaps on the river
banks. The annual movement of such large quantities of ice is accompanied
by results of geological interest.

Rock Surfaces polished and scratched by River Ice.— The banks of the Yukon
where they are precipitous are frequently smoothed and polished in the space
between high and low water. The surfaces best showing these characteristics
are on the up-stream side of bold promontories. In such localities the smooth
surfaces are not infrequently scratched in an irregular manner. The scratches
are rudely parallel to the direction of the river current, but are not deeply
engraved. On the down-stream side of projecting rocks and cliffs the sur-
faces are rough and without striatious. These records are clearly due in la rge
part to the friction of ice descending the river. The scratches are mad.' by
sand and pebbles frozen in the ice.

* The behavior of northern rivers in winter has been described by A. C. Inderson, in Jour.
Geograph. Soc. London, Vol. 15, 1845, pp. 307-371.

11^ 1. t . RUSSELL URFACE GEOLOGY OF A.LASKA.

Bowlders Transported by River lee. — The first large bowlder that I .saw in
ascending the Yukon, the travels of which couhl be approximately measured,
was mi thr let! bank of the river, about fifteen miles above Nbwikakat. This
is a granite bowlder, measuring 4 by 3 by •">■] feet. The ledge from which it
ii i u~t have been derived is in the Lower Ramparts, about one hundred miles
above its present position. < >ther bowlders, many of them larger than this,
were seen al many localities, but the distances they had traveled were not
ascertained. The largest one measured was near McGrath's Station. It is
composed of dark, volcanic rock, is rudely spherical, and measures a little
over six feet in diameter.

Bowlders were frequently observed just above high-water mark, where the
river banks are low and composed of sand and gravel. These had evidently
been forced landward by ice pressure during the breaking up of the river in
spring. The furrows plowed during their advance, as well as the hank of
sand and gravel accumulated in front, could still be distinguished. The
force which moved these bowlders was plainly the river ice. When the direc-
tion of movement could be determined, it was always found to have been
down Btream, but at the same time trending away from the river at an angle
of from 30 to perhaps 50°. The direction of movement, as well as the fact
that the bowlders occur at high-water mark, and often a little above that
horizon, shows that they must have been disturbed at the time when the river
was at it- flood stage, and expanding so as to force ice over its hanks.

It is well known that when a river is rising the drift-wood it carries ten Is
to travel towards the shores, and frequently become.- entangled in the vege-
tation on the hanks. When falling, the drift -wood tends towards the line of
swiftest current. A similar rule controls the direction taken hy the floating
ice during spring freshets. I have been informed by persons who have wit-
nessed the breaking up of the Yukon in spring, that ice in immense cakes is
frequently forced up on the shore to a height of ten or fifteen feet, and re-
main- long after the river ha- fallen and is clear of ice. It is during the

:umulation of such ice heaps that bowlders are moved in the manner de-

ibed abov.e. Scars and marks of abrasion, due to ice, are frequently seen
■ hi tne trunks al a height of ten feel or more above tic high water line of
the river.

Furrows in the sands of the river banks which had been formed by blocks
ice forced shoreward in the same manner as the bowlders just described

were observed at many localities. In these instances the shape.- of the ice
cake.- could he clearly distinguished in the banks of -ami. frequently three
■ or more in height, that had been forced up in front of them. Prom the
manner of formation it is obvious that the furrows made by bowlders and
ice as just described are transient features, obliterated ami renewed at each
iking up of tin- ri\

RECORDS MADE BY RIVER ICE. 11(.)

Gravel Heaps deposited by Elver Ice. — On the low, sandy shores of the
Yukon, especially on the up-stream ends of low islands, there are frequently
heaps and ridges of gravel accumulated by the ice. The simplest of these
deposits are heaps of rounded, water-worn stones and bowlders, resting on a
sand flat. They are of all sizes up to those containing two cart-loads or more
of material. Down-stream from those heaps which occur below high-water
mark, there is frequently a trail of fine sand, tapering to a point some fifteen
or twenty feet distant, showing that water has flowed over them and deposited
sand in the eddy below.

In other instances, also quite common on low, sandy shores, the gravel
was arranged in ridges a few inches high, which intersected and crossed one
another so as to enclose bare, slightly basin-shaped spaces, from a few inches
to several feet in diameter. Sometimes these ridges of gravel bore a fanciful
resemblance to letters, as if some one had tried to write an inscription on
the sand by piling up lines of gravel. Again they were more regular, and
enclosed depressed areas that looked not unlike gigantic tadpole nests.
These resemblances, however, are mere fancies.

The explanation of the presence of the ridges and of the gravel heaps is
to be found in the action of ice on the river banks during high water: The
ice adheres to the bottom of the river in many places during the winter and
is floated away in large cakes when the spring freshets come. The bottoms
of the cakes are charged with gravel, and when they run aground on low
shores, as often happens, and are melted, their load of stones is left behind.
In the heaps of ice formed on the shore the blocks are frequently turned on
edge, and on melting in that position leave the low ridges of gravel described
above.

When low, sandy shores are covered with cakes of ice, leaving cracks
between, the gravel transported in the manner described finds lodgment in
the cracks, and when the ice melts forms ridges, some of which intersect and
enclose bare, sandy spaces.

Pebbles Faceted, Polished, and Scratched by River Ice. — The most interest-
ing records made by river ice in Alaska occur on pebbles that are set in a
matrix of tenacious clay, and form a pavement along the river banks. A
typical instance of this nature was observed on Porcupine river about one
hundred miles above its mouth. At this locality the steep bluff overlooking
the river is formed of tenacious blue clay and capped by a layer of water-
worn pebbles of various kinds and sizes. The pebbles on falling to the river
beach become imbedded in clay so as to form a veritable pavement along
the river over a space about one hundred feet broad during low water and
more than a mile in length. The upper surfaces of the pebbles set in the
clay have been ground down or faceted. The surfaces of the facets arc
smooth and crossed by striations which are in general parallel with the

ll'll I. C. RUSSELL — SURFACE GEOLOGY OF ALASKA.

course of the river. The pebbles thua marked resemble glaciated pebbles so
closely that I took special pains to determine tbe origin of their peculiar
markings. Only the upper surfaces of the pebbles taken from the pavement
weir abraded. Moreover, uo pebbles showing the markings referred to were
found above high-water mark. That the pebbles were ground down, polished
and striated by the river ice passing over them during its descent of the river
is plainly apparent.

Some of the Btones in this pavemenl arc angular masses of basalt, nearly
two feet in diameter. These, like the associated pebbles, are deeply abraded
and scratched in rudely parallel lines. On some of the rounded pebbles the
amount worn off on the abraded side was estimated to have been about half
an inch.

Many of the Btones in this locality are so similar to glaciated pebbles that
it' removed from their normal position to a glaciated region, even the most
acute observer would attribute their markings to glacial action. When,
however, one knows the origin of the markings upon them it becomes evi-
dent that the scratches on the smooth faces are less regular and less firmly
drawn than the groove.- and striatums on typical glaciated pebbles.

"Bowlder Clay" deposited by Rivers. — The Yukon, as already stated,
freezes deeply during the winter, and the ice near its borders, especially
where it is broad and .-hallow, rests on the bottom, and has large quantities
of stone and bowlders attached to it. All except the largest of the tributary
streams freeze to the bottom, and also furnish vast quantities of pebbles for
ice transportation. When the rivers break up in the spring, the ice with
it- loads of stone is floated down-stream, and, melting as it goes, distributes
pebbles and bowlders over the bottom of the river, and in places where at
other time- tine sedimenl i- deposited. In this manner it is conceivable that
a clay tilled with bowlders mighl he formed which would similate true bowl-
der clay in many ways. Certain bowlder clays along the Yukon and the
Lewes are described elsewhere in this paper, which, as there stated, may
have been formed in the manner here suggested.

Old Deposits of ice-borne River Gravel. The pasl action of the river ice
in transporting stones is recorded by deposits of bowlders in lenticular masses
in the fine sedimenl exposed in the river bank-. Isolated bunches of gravel
wholly enclosed by fine sediment, and ten to fifteen feet below the surface,
are ool unusual in the caving river hank-. In -Mine places large bowldi

i en in like -in mi ion-. These occurrences are satisfactorily accounted
for on the hypothesis thai the gravel and bowlders in question were trans-
ported and dep< -ihel by river ice.

Flood-Plain I>>/><>ii-. The manner in which rivers build up, destroy, and
rebuild their Hood plain- can lie studied to advantage at many place- on the

Yukon and Porcupine. The lower hundred mile- of the latter offers an

FLOOD-PLAIN DEPOSITS OF THE YUKON. ] -_> |

especially interesting region for such study. This portion of the Porcupine
flows through a low, densely forested region, which is an extension of the
lowlands of the Yukon already described. Its course is extremely tortuous,
and in fact forms a continuous series of gracefully sweeping curves. In its
meanderings it cuts away the banks on its concave side, and deposits the
material removed lower down on its convex side. In this way a marked
contrast in the character of its banks has been produced. On the outer
curves the banks are precipitous, owing to the undercutting of the river.
They are uniformly about twenty feet high, and densely covered with fully
grown spruce trees. The river has cut a swath through the forest and left
the trees standing on its border as the grain stands beside the path of the
reaper.

On the inner curves the banks are low and gently sloping, and near the
water are bare of vegetation. Proceeding up the shelving shore, one comes
first to coarse grasses and yellowish-green Equisetums. Beyond this belt is a
growth of young willows, which iucrease in height away from the river, and
soon form a dense growth thirty or forty feet high. Mingled with the willows
and replacing them on the landward side are clumps of alders and groves of
poplars. Beyond this belt lies the unexplored spruce forest, which stretches
away for miles and densely covers the land to and beyond the distant hills.

The immediate border of the river on the convex curves is formed of
current-bedded gravels. Going up the beach one comes to sand banks,
which in their turn pass beneath deposits of fine silt. These are the flood-
plain deposits of the river, and are arranged in a definite sequence resulting
from their mode of deposition. The gravels are deposited by the swift waters
along the border of the main channel, while the finer superimposed strata
are spread out by the slack water on the margin of the stream during its
flood stages.

Fresh-water shells were frequently observed in the finer deposits. Cross-
bedding, common in all the strata, is best defined in the coarse deposits. At
times the sand and silt layers are finely laminated, and may closely resemble
lacustral deposits. In one instance a layer of coarse sand more than twelve
feet thick was observed. Though deposited by the river it was homogeneous
throughout, and did not exhibit a single line of stratification or cross-beddiDg.

As the river slowly changes its course by taking from one bank and
depositing on the other, the sheets of debris it spreads out are increased by
additions to their margins, preserving at the same time their order of super-
position.

Within the forest there is a dense growth of mosses ami lichens, decaying
beneath while growing above. This process superimposes a layer of peal
on the deposits spread out by the river. The soil is every where frozen at a
depth of about a foot below the surface.

122 I. C. I : I — 1 : 1 I 1 RPACE GEOLOGY OF ALASKA.

A section of the flood-plaiu deposits of the Porcupine where no complica-
tions occur presents the following divisions in their natural order and
approximate thickness* - :

Peaty layer 2- 3 feet.

Fine sill 3-5 "

Sand 3- 6 "

Coarse current-bedded gravels and sand. _. 1">~;0 "

The continuity of the strata just described is broken when the river cuts
across a bend, as frequently happens, and a new series of deposits is begun.

A decrease in the grade of the stream from any cause, as orographic move-
ment for example, would admit of the superposition of one flood-plain series
upon another. An occurrence of this nature seems to have taken place in
the low lands of the Yukon abovethe Lower Ramparts, where a layer of peat
is interst ratified with current-bedded sands and gravel. An increase in the
grade of the stream would enable it to deepen its channel and leave portions
of its Quod-plain as a terrace along its borders. A similar record would be
made by a stream descending a stable declivity, by the erosion and deepen-
ing of its channel, thus leaving portions of its flood-plain to record horizons
at which it remained for a considerable time.

Terraces along the Upper Yukon record the fact that the stream at one
time flowed several hundred feet higher than at present, and in deepening its
channel, probably on account of orographic movement, left portions of its
tl 1-plaiu on the sides of its valley.

Mum ninth Remains in the Banks of the Yukon. — Teeth and tusks of the
mammoth, associated with large bones, are reported to occur in abundance
at two principal localities along the Lower Yukon. I was not fortunate
enough to find any of these fossils myself, but saw several that had been
found by others. < »ne of these localities is near the head of the delta, but I
was not able to learn it- exact position. The other is On the lefl bank of
the river between Nowikakat and Nuklukahyet, about forty miles below the
mouth of the Tananah. Its position is indicated by the word " Palisades "
on the [J. S. Goast and Geodetic Survey map of "Alaska and Adjoining
Territory," and on the small map ( pi. 2) accompanying this paper.

The bluffs at the Palisades are approximately three hundred feet high,
level topped, and composed of fine, light-colored, evenly stratified sediment-.
Back from the bluffs is a level, densely wooded table-land, with swamps and
ponds, bordered on all Bides, except thai adjacent to the river, by bold hills.
The Palisades proper are washed by the river, and form precipitous bluffs
entirely bare of vegetation. The same escarpment extends some ten miles
up the river, clothed with vegetation, and with a densely wooded flood-plain
along it- base. The portion ol the escarpment now washed by the river.

.MAMMOTH REMAINS OF NORTHERN REGIONS. L23

according to Captain Charles Peterson, of the steamboat " Yukon ", is com-
posed of frozen " sand." The fact that the strata are frozen accounts for the
steepness of the escarpment. As the river washes away its hanks, large
numbers of bones, teeth, and tusks are exposed. I was in formed also by
Peterson that the deposit near the delta is of the same general character as
the one here described.

The position of the strata forming the bluff at the Palisades, as well as
their regularity of stratification and fineness of material, indicates a lacustral
origin. What is known of their fossils suggests Pleistocene or Tertiary age.

The banks of the Yukon in the lowlands above the Lower Ramparts, and
at many localities lower down stream, are formed of flood-plain deposits and
are much more recent than the high bluffs at the Palisades. From this,
together with what I learned concerning the occurrence of detached bones,
teeth, etc., at many places along the Lower Yukon, it seems very probable
that they were not in the original place of interment, but had been washed
out of the bluffs at the Palisades, or other similar deposits, and transported
down stream. Similar bones have been found above the Palisades, however,
and I suspect that other " bone beds " exist higher up the river.

It is necessary to note that the statements just made do not seem to har-
monize with the observations of Dall and others, who found mammoth
remains in the earthy layer on top of the ice cliffs near Kotzebue sound.
The vertebrate fossils in the stratified beds at the Palisades certainly seem
to be older than the similar remains occurring on the surface of the tundra.

Extinction of the Mammoth. — It is an interesting fact that all the bones of the
mammoth and of other large animals that have been found in Alaska occur,
so far as 1 am aware, in regions not glaciated during the Pleistocene period.*
The relation of mammoth remains to the distribution of glaciers in Alaska
acquires additional importance in view of the fact that no evidence of glacia-
tion has been reported in northern Siberia, where similar mammalian remains
are also abundant.

The study of glacial records by various observers has shown that the great
Pleistocene glaciers of this continent extended outwards in all directions
from two main centers of accumulation, one in Labrador and the other in
the northern part of the Rocky Mountain region. During their greatest
extention these two great glacier systems seem to have been confluent, so
that a vast ice field stretched across the continent from ocean to ocean.
The northward movement of the ancient ice sheet was not 'sufficient in all
places to reach the Arctic ocean. In view of this fact, it may be suggested
that the abundance of mammalian hones in the nonglaciatc.l regions in the
far North is due to the crowding northward and final extinction of land

**The absence of glaciers in central and northern Alaska is discussed elsewhere in this pitper.
XVII— BtftL. Geol. Soc. Am., Vet,. 1, I-

1 'J I [. C. RUSSEL1 1 RFA< I GEOLOGY OF ALASKA.

animal- of the Pleistocene period by the advance of continental glaciers
from the smith.

I venture to suggest that a similar sequent f events will appear in the

later geological history of Asia when the Burface geology of thai continent
ie more fully investigated.

/' vation of. Fish Remains. — The annual migrations of the salmon in
the rivers of northwestern North America are of interest t" the geologist,
since they die in vast numbers and arc buried and preserved in the sedi-
ments now formii

I saw lai ge numbers of dead Balmon in the upper Yukon and in the Lewes.
The largest number seen was. however, in the Taiya river, near its month.
At this place the " dog salmon " were crowding up the stream in thousands,
and thousands that had previously made the ascent were already dead. The

Taiya river has several mouths, and the water in many of these was so shal-
low at the time of my visit that the hacks of the Balmon were exposed as
they persistently worked their way up stream. 'The waters were falling, so
that many [tools and sloughs had ceased to he connected with the main
stream. In these somewhat stagnant waters the fish were concentrated bo
a- to completely conceal the bottom. The water from the river that reached
these pools, already partially filled with mud. was charged with glacial silt,
and a deposit of tine sediment was being formed aboul the dead fish, which
might, under favorable conditions, completely bury them. Large numbers

of dead fish also floated down Stream, and must finally have sunk to the
bottom in -alt water. As the delta of' the Taiya is growing rapidly, the
< ■• ' 1 1 ' I i i i> ' 1 1~ for preserving large numbers of fish, belonging to a few species,
are ex© edingly favorable.

'I"le- occurrence described is in no way exceptional or novel, hut takes
place every year in many places. It serves, I believe, to explain the pn
ence of large numbers of fossil fishes in certain rock-, a-, for example, in the
.V wark By stem, near Boonton, N< w Jersey, where fishes of a class that now
inhabit rivers and lake- occur packed together by hundred-, if not by thou-
sands, in a fine -hale associated with coarse conglomerates.

NAVIGATION OF THE YUKON IND ITS TRIBUTARI] 3.

1 itain Peterson ascended the Yukon last summer with the steamboat

' Yukon "' a- far a- the mouth of Telly river, which i^ al t one hundred

miles farther than any steamboat ha- hitherto gone. The trip up the Por-
cupine wa- the first venture of a steamboat on that river.

In ascending the Porcupine we left Port Yukon in the forenoon of August

led the limit of navigation, about forty mile- below the Ram pari

H • . :it i u on August ''>. Had tie ascent he. n made a f. w days earlier,

ince COUld have l„ , Q U;\\ igated, because the water had recently

NAVIGABILITY OF ALASKAN RIVERS. L25

been much higher. At the time of our visit it was rapidly falling. The
return trip to Fort Yukon was made in about eighteen hours.

The " Yukon " did not pass the mouth of Pelly river, as that was her des-
tination. She might easily have done so, however, had it been desirable.
She could have ascended the Yukon to and beyond the mouth of the Lewes,
and could also have ascended the Lewes as far as White Horse rapids, just
below Miles canon. The only place below White Horse rapids which seems
to offer special difficulty is at Rink rapids (Five Fingers), where the river is
obstructed by islands and the current is very swift.

Above Miles canon the river is navigable for small steamboats all the way
to lakes Tagish and Bennett. The grand scenery of the numerous lakes
drained by the Lewes would attract many tourists should steamboats be
placed on them.

The Tundra.

geology of the treeless, moss-covered shores of alaska.

Definition. — The name " Tundra " is used in Siberia to designate the vast,
treeless, moss-covered plains bordering the Arctic ocean and has been
adopted for the similar regions fringing the northern shores of North America.

A general knowledge of Alaska derived from many sources* renders it
evident that the tundra occurs all along the borders of Behring sea and the
Arctic ocean. My observations concerning it were limited to the region
about St. Michaels, to the delta of the Yukon; and to the less typical shores of
Unalaska.

General Characters. — The tundra in typical localities is a swampy, moder-
ately level country, covered with mosses, lichens, and a great number of small
but exceedingly beautiful flowering plants, together with a few ferns. The
soil beneath the luxuriant carpet of dense vegetation is a dark humus, and
at a depth exceeding about a foot is always frozen. On its surface there are
many lakelets and ponds surrounded by banks of moss even more luxuriant
than on the general surface. It is not always a level plain, however, but is
frequently undulating and may surround and completely cover hills of con-
siderable elevation. The dense tundra vegetation also extends up the
mountain side aud occupies the entire region where the conditions are favor-
able for its formation. At the localities where I examined it the whole
surface, excepting the faces of steep cliffs and thesummits of high mountains,
was covered with the same dense brown and green carpet.

About the shores of Unalaska and for fully 2,000 feet up its rugged

*The tundra of Alaska have been graphically described by the following writers :

John Muir- Botanical Notes on Alaska; m Cruise oi tin- Revenue Steamer Corwin m Alaska and
the N W. Arctic ocean in 1881. Treasury Department, Washington, 1883, pp. I.

0. L. Hooper: Report of the Cruise of the U. S. Revenue Steamer Ihomas Corwin in the Arctic
Ocean. 1881. Treasury Department, Washington, 1884, p. 35.

L. M. Turner: Contributions to the Natural History of Alaska. Signal Office, Washington
pp. 15-16."

L26 1. C. RUSSELl LTRFAC] GEOLOGY OF A.LASKA.

mountain Blopee the vegetation is essentially the same as at St. Michaels. In
climbing the Bteep Blopes about Iliuliuk I often had great assistance from the
dense mat of vegetation two or three feet thick, which, clingingto the rocks,

converts their angular crags and shattered crests into s oth domes of soft,

yielding < >n the Bteep Blopes, as in the swamps, the vegetation is

always water-soaked, owing to the extreme humidity of the climate in which
it thrives. Lakelets are common on slopes and hillsides that would be well
drained were it ool for the spongy nature of their mossy hanks.

About >t. Michaels and on the delta of the Yukon the tundra is typically
developed. The characteristics are the abundance of mosses and lichens and
the absence of trees. Cryptogamic plants make more than nine-tenths of its
mass. On their power to grow above as they die and decay helow depends
the existence of the tundra.

The varied vegetation of these moorlands, although seldom more than a
few inches high, is exceedingly luxuriant and beautiful. The soft greens
and delicate browns of the mosses and lichens make a most artistic setting
for the bright blossoms and glowing fruits of the flowering plants. In some
localities, usually in sheltered situations near the lakelets, small groves of
alders and dwarf willows reach a height of three or four feet, hut these ex-
ceptions to the usual character of the vegetation arc lost to view in the broad
treeless expanse.

On bright Bunny days, and such days are not uncommon in summer on
the usually bleak shores of Alaska, a walk on the mossy fields of the tu ml ra,
which at a little distance look like luxuriant pastures, is very enjoyable
although exceedingly fatiguing. On wild stormy days, when sleet and snow
add to the gloom of a leaden sky. and a cold, piercing wind sweeps in from

the sea, the boundless moorlands, without a sign of human existence, are

dreary and depressing in the extreme.

Birds inhabit the tundra in great numbers during the summer, and many
species, after t heir long migration-, find t here a congenial home in which to
rear their young. The bird life of this peculiar region has been studied by
W. II. Mall, L. M.Turner, E. W. Nelson, and others, hut due- not claim
our attention a! present, a- only the geological features of the tundra and of

the general mossy covering of Alaska can be considered in these pag<

Woa\ of Formation. On making excavations in the tundra, a- well as on

imining natural sections, I found that the fresh, luxuriant vegetation at

the Burface changed h\ insensible gradations to dead and decaj ing matter a

few inches below, and finally became a black, peaty humus.' retaining but

few indications of \\- vegetable origin. In an excavation made at St.

Micha< the 13th of July, the t Ira was found to he frozen below a

depth "f eight inches. Where the moss is more open and more luxuriant,
the depth to the frozen Bubsoil was about fourteen inches.

THE GEOWTH OP THE TUNDRA. L27

The depth of the humus layer beneath the moss was found to be about two
feet, at St. Michaels. A mile east of the village it was about twelve feet. In
the delta of the Yukon a depth of over fifteen feet was seen at one locality.
As satisfactory sections are rare, these measurements do not indicate its
average thickness. A depth of 150 to 300 feet has been assigned by several
observers to the tundra where it is exposed in a sea-cliff on Eschscholtz bay,
at the head of Kotzebue sound. This interesting locality has received more
attention than any other similar portion of the shore of Alaska, owing to the
fact that the ice is there well exposed and the surface layer of humus is rich
in mammalian remains.*

Ice cliffs similar to those in Eschscholtz bay, but of greater extent, occur
along the Kowak river, which empties into Kotzebue sound. These ice
deposits have been described and illustrated by J. C. Cantwell,f who sug-
gests that they may be the remnant of a frozen river.

The explanation of the formation of the tundra is to be found in the fact
that its vegetable covering grows at the surface and dies and decays below,
but is frozen before complete decomposition takes place. The surface of the
frozen substratum rises as the thickness of the protecting carpet above is
increased. There is apparently no reason why this process might not con-
tinue indefinitely, so as to store up vegetable matter in a way that is only
paralleled in the most extensive coal fields.

A possible Origin of Coal Seams. — So vast is the amount of vegetable mat-
ter now imprisoned in the tundra of the North, that I venture to suggest that
possibly some coal seams may have had a similar origin.

This suggestion does not seem so very unreasonable when one remembers
that except in the circumpolar tundra, deposits of vegetable matter are no-
where accumulating at the present day to anything like the extent or thick-
ness required for the formation of coal-fields like the one, for example, of
which Pennsylvania still retains a remnant. Botanists will say at once, in
opposition to this suggestion, that the flora of most of our coal-fields, and
especially those of Paleozoic age, indicate tropical or sub-tropical conditions.

* Descriptions of this locality may be found in the following books:

Otto von Kotzebue : A voyage of discovery into the South sea and Beering's straits, for the pur-
pose of exploring a northeast passage. Undertaken in the years 1815-1818. London, 1821, 8vo, vol.
1, pp. 219-220.

Captain Beechev : A narrative of the voyage and travels of Captain Beeohey, R. N., F. B. 8., &c,
to the Pacific and Bearing's straits; performed in the years 1825, '26, '27, and '28. London, 8vo,
pp. 372-377.

W. H. Dall : Extract from a report of C. P. Patterson [On Coast Survey work in Alaska]. Am.
Jour. Sci., 3d ser., vol. 21, 1881, pp. 104-111. . ,

C. L. Hooper: Report of the cruise of the U.S. Revenue-steamer Corwin in the Arctic Ocean [in
1880]. Treasury Department, Washington, 1881, 8vo, pp. 24-25.

C L Hooper: Heport of the cruise of the U. S. Revenue steamer Thomas Corwin, in the Arctic
Ocean. 1881. Treasury Department, Washington, 1884, 4to, pp. 79-81. PI. op. p, so

VV. H. Dall: Glaciation in Alaska. Bull. Philosophical Society of Washington, vol. 6, 1884, pp.

t A narrative account of the exploration of the Kowak river, Alaska; in Reporl of the Cruise of (he
Revenue Marine Steamer Corwin in the Arctic ocean in the year 1885, by Capt. M. A. Bealy,
Treasury Department, Washington. 1887, pp. 48-49, and plates op. p. 48.

128 I. i. RUSSELL — SI IMAM. GEOLOGY OF A.LASKA.

The flora of the tundra, however, like the plants of the Carboniferous, is
essentially and characteristically cryptogamie. Two species of Equisetum,
which maybe considered a- representing tin- Calamites of former times,
flourish with rank luxuriance over great areas along the Yukon.

It' the tundra-friDged coasl of Alaska should subside, the peaty layer with

which it is covered would be< le buried beneath Bands and clays, ami form

a stratum in every way favorable for transformation into lignite and coal.
The plant ami animal remains associated with it would indicate the climatic
conditions under which ii accumulated, hut the overlying Bandstones ami
shales might also carry leaves ami tree trunks transported by rivers from
warmer regions.

Lakes on Hi' Tundra. — The surface of the tundra, as already mentioned,

i- frequently diversified by | Is and lakelets. Moat of these have no definite

nutlet, bul are c< mi ] -let el y surrounded by luxuriant hanks of moss, through
which the water escapes as through a sponge. The moss encroaches on the
lakelets from all side-, and finally completely covers them in the same man-
ner as the Sphagnum increases about the borders of ponds in the peat hogs
of New England and other temperate regions. As the moss covers the lake-
let- more and more completely during a series of years, the ice formed by
the freezing of the water in winter i- more and more thoroughly protected,
ami 18 finally completely shielded from tin; heat of summer. A body of
clear ice is thus formed in the tundra, similar to the Btrata of ice exposed at
certain localities along the coast of Behring sea and in the hanks of the
Yukon.

This explanation of the presence of clear ice in the tundra has previously
been Bl I bj I.. M. Turner in the introduction to his report on the

natural history of Alaska, already referred to. A similar explanati f

the presence of thick beds of clear ice in the cliffs bordering Eschscholtz
bay has been recorded by E. \V. Nelson and ('. L. Hooper,* together with
an alternative hypothesis to the - Hi ct thai the ice mighl have resulted from
tin- freezing of water which filtered through the surface layer of moss.

Stratified I" '» tin Tundra.- The great Dumber of lakelets on the surface
of the tundra renders it evident that if their extinction ami the consequent
burial of ice beneath the Burface lake- place in the manner Bupposed Bheets
of ice, probably more or I- -- lenticular in Bhape, should form a characteristic
i. ature of tundra deposits. The origin of the lakelet- may perhaps he due
to tic accumulation of snow hank- on the tundra, which by their late melt-
ing enable the me-- surrounding them in grow more rapidly than on the
more deeply covered area-. In this way a depression in the surface would

l.e formed which WOUld he flooded after the -lluU melted. A lakelet mice

' orw in, in ii,-
Dgton, 1884, p

DEPTH OF FROST AND ICE IX THE TUNDRA. L29

started would perpetuate itself from year to year until the growth of moss
from the sides led to its burial. An origin of this nature seems probable,
as the lake basins are due entirely to variations in the surface growth of
vegetation and not to inequalities of the substratum of rock or clay on which
the humus layer of the tundra rests. The origin and extinction of lakelets
is thus a part of the normal growth of the frozen moss-covered plains.

MOSSY COVERING OF THE WOODED PORTION OF ALASKA.

Distribution of the Mossy Covering. — The tundra is confined to the vicinity
of the coast, where for some reason, probably climatic, trees do not grow.
Inland from this belt, however, the mossy covering still continues and
occupies a vast area, especially in the lowlands bordering the Yukon and
other large rivers. Without exaggeration, it may be stated that the whole
of Alaska, excepting the steepest rock slopes and the tops of high mountains,
is covered with a dense carpet of moss.

On the flood-plains of the larger rivers, and generally throughout all the
lowlands of Alaska, peaty deposits are forming in the same manner as on the
tundra, modified, however, by the growth of arborescent vegetation and by
the intrusion of sand and clay in places that are flooded during the high-
water stage of the rivers.

At many localities along the Yukon sections of peaty deposits are exposed
often eight or ten feet thick and several miles long. The bluffs where these
layers occur are usually from fifteen to twenty feet high and nearly always
frozen solid, except where they are too open in texture to retain water.
Some of the vegetable layers are interstratified with sand and clay, as already
explained ; others at the surface are still increasing in thickness and have a
dense forest growing on them. Not infrequently there is a stratum of clear
ice interbedded with the layers of peat, sand, and clay.

Depth of the Frozen Stratum beneath the Moss— -The thickness of the frozen
substratum beneath the moss-grown forest has never been determined. The
deepest excavations that have been made show that it exceeds twenty-five

feet.

At Nulato a well has recently been dug near the river bank through clay
and sand to the depth just mentioned, in which the material removed was
frozen solid, with the exception of certain dry sandy layers. At Forty-mile
creek precisely similar conditions have been revealed by mining operations,
the depth reached being also about twenty-five feet..

The reason for the great thickness of the frozen layer at these localities
seems to be that deposition and freezing went on at the same time Th<
certainly seem to be the conditions under which the great thickness of frozen
material beneath the tundra and in the flood-plains of the larger rivers of

130 I. C. RUSSELL URFACE GEOLOGY OF ALASKA.

Alaska have been accumulated. It seems to me that this must also be the
explanation of the origin of all frozen deposits which* contain alternating
strata of clear ice and of frozen layers of mud and peat like those exposed
in the borders of the tundra and along the banks of the Yukon.

Depth of Frost in On Arctic. — As recorded by K. E. Von Baer,* the ground
at Yakutsk, Siberia, is froz< n to the depth of 382 feet. It has been assumed
by various authors that the great depth of ice in this and other similar
instances is due directly to surface temperature, the downward limit to which
the winter's cold can penetrate being limited by the internal heat of the
earth. Before accepting this explanation as final it should be ascertained
whether the strata at the localities where a great depth of frozen material
has been encountered might not have been frozen progressively as they were
laid down.

Being skeptical as to the influence of the low temperature of northern
land.- mi the strata at a depth of two or three hundred feet below the surface,

1 consulted R. S. W Iward, of the V. S. Geological Survey, who has kindly

furnished the following discussion of the question:

The considerable depth below the earth's surface to which frost or the*temperature of
freezing i* known to penetrate in the Arctic regions, raises the interesting question of
the relation between the thermal properties of the earth's crust and the time and depth
of penetration. When any portion of the earth's Burface is subjected to a temperature
differing from that of the crust below, the process of heat diffusion or How of heat from
the warmer t<> the colder parts of the crust is at once Bet up. The rate at which this
process goes "ii and the resulting distribution of temperatures will depend, for any
given Bet of temperature conditions, on the conductivity and thermal capacity <>t' the
crust. Within such ranges of temperature as we have to consider here the conduc-
tivity and thermal capacity of the crust will remain invariable, and they will enter
the relation Bought as a ratio, which ratio is called diffusivity. With a constant dif-
fusivity, therefore, the form of the relation in question will be determined by the
temperature condition-. Of these a variety can be imagined ; but a sufficiently defi-
nite idea of the nature <>f the process may be gained by supposing that at the begin-
ning of the time the crust to a depth of a thousand or two thousand feet has a uniform
perature, and that the Burface of the crust from and alter the initial epoch is main-
tain i. -taut temperature. The maintenance of a constant temperature is
tically what results at the surface when a considerable portion of it i- covered by

iand ice i in .lour. Roy. Geograph. Soc. London, vol.8, 1838, pp.

i and subsoils of northern lands is also treated by the
■

depth of frozen strata a( fakutak]; in Jour. Roy. Geograph. Soc

:»• of the earth in Biberia; in Jour, Franklin In-i. N. B., vol.

rhich ii Is desirable to make on the frozen soil of
ondon, vol. 9 1939, pp, 1 it I
John 1 America; In Edinburgh New Phil, lour, vol.

II, it 1 1'

■
1 1. ii imer Thomas Corwin in the Arctic

NORMAL COOLING OF THE GLOBE.

131

a mantle of ice. Under these circumstances the temperature at points in the crust
will fall towards that at the surface in a way defined thus :
Let

ua == the initial excess of the temperature of the crust over the constant tempera-
ture at the surface,
M = the temperature of the crust at a depth x at any time t after the initial

epoch,
«2=:the diffusivity of the crust = 400, about (Thomson*), for foot and year as

units,
tt = 3.14154-,

.- = subject- variable of integration,
e = Naperian base.
Then the fall of temperature u0 — u is expressed by the equation

iay't
u0 — u = ua ( 1 — - J e 2 </ z \

The following table gives the values of _5 for various values of the depth x

and the time t:

Values of Ratio

u0 — u

for Different Times and Depths.

Depth ./-.

TIME

PROM INITIAL EPOCH.

1 year.

25 years.

100 years.

1,000 years.

10,000 years.

Feet.

40-

80 ...

0.1573
0.0046
0.0000

0.7773
0.5715
0.3961
0.2579
0.1573
0.0046
0.0000

0.8875
0.7773
0.6714
0.5715
0.4795
0.1573
0.0046
0.0000

0.9643
0.9287
0.8933
0.8580
0.8230
0.6547
0.3711
0.1797

0.9887
0.9774

120

160

0.9662

0.9549

200

0.9436

400 ._ .

0.8875

800 .

0.7773

1,200

0.6714

To illustrate the application of the table, suppose the mean annual temperature
over the Alaskan region to have been 10° F. (the present mean annual temperature
of northern Alaska) since the initial epoch, and suppose that the temperature of the
crust was initially 60° F. Then the uQ of the formula is 50°. At the end of a year
from the initial epoch the temperature at a depth of 40 feet (see table) would fall
0.157 X 50°, or about 8° ; i. e., the temperature at that depth would be 60° — 8° := 52°.
At the end of 25 years the temperature, at the depth of 40 feet, would fall to about
60° — 0.777 X 50° = 21°; but the fall would be hardly perceptible at a depth of 400
feet, etc.

:See Treatise on Natural Philosophy, by Thomson and Tait, Vol. 1, Part u, Appendix I'.
XVIII— Bull. Geol. Soc. Am., Vol. 1, 1889.

L32 I. C. RUSSELL CJRFACE GEOLOGY OF ALASKA.

It n | » J < • • : i r - {rem the formula and the tnt»lo that the <!<■) >t h< to which any specified
full of temp tes vary inversely as the square runt- of the corresponding

tim

To And liow l')iiL,r a time is required to produce a given fall in temperature at a

given depth, we must find / from the pr ding equation whe"n all the other factors

are known. Thus, Buppose that, under the conditions assumed in the above example,

we require the time when the temperature will full to 30° at a depth of 200 feet, the

equation becomi

200

40 , i

30 . 2 r — •

— - = 1 — — : — : I e dz

This | 180 j

The conclusion reached by Mr. Woodward indicates that the freezing of
eveu the deepest ice-stratum reported in the Arctic- might have resulted
directly from a mean annual temperature no lower than now prevails in
northern Alaska. The conductivity of the frozen soils and subsoils of
Alaska lias not been investigated, but is probably less rapid than in the
strata in which the value determined by Thomson and Tail was obtained.
Other values may be substituted in the formula, out any probable variations
from those used would not affeel the general conclusion reached.

Although tin- passage of hrnt through the surface layers in Arctic regions
i- bIow, yel it is apparent that the length of time since a mild climate existed
there is sufficient, even under existing conditions, to allow of the freezing of
strata Beveral hundred feet below the surface. The mean annual temperature
pfthe nonglaciated portion of Alaska during the glacial epoch must have
been lower than at present — at least such 1 am confident would be the con-
clusion of the majority of geologists, — and their Beems good reason for believ-
ing that the freezing of the tundra began In Pleistocene time and continued
to the present day. An increase in the thickness of the frozen layer, owing
to the influence of a mean annual temperature below 325 F.and the deposi-
tion of a succession of frozen layers, as suggested elsewhere, may have com-
bined to produce the results now observed.

THE FROZEN MOSS-LAYER IS \ GEOLOGICAL IGENT.

Throughout Alaska drainage is obstructed by the universal mossy cover-
ing. There is an absence of -mall Btreams; rills and even creeks of con-

rable size arc frequently ponded and transformed into swamps by the
progressive growth of vegetation from their banks. Not only are the denud-
ing effects of rain-drops falling on the land entirely counteracted by the
most areas, but the water is retained by the sponj

mo-- and allowed to Beep -lowly away. The Btreams formed by the water

r tillering through the moss are clear and limpid, and consequently unable

EFFECT ON DRAINAGE OF A FEOZEX MOSS-LAYER. L33

to corrade. Their ability to dissolve the rocks with which they come in
contact is also greatly reduced by their low temperature. Moreover, the
banks of the streams, and even the bottoms of the smaller rivulets, in many
instances, are moss-covered, and the soil beneath the moss is frozen. The
erosive power of surface water is thus reduced to a minimum. Only the
larger creeks and the rivers obey the laws of erosion and of corrasion which
are in force in warmer and less humid regions.

Another result of a low mean annual temperature in a humid region is
that dead vegetation decays slowly, and prostrate trees and obstructions to
drainage formed by drift-wood remain a long time, thus retarding the streams
and favoring sedimentation. Many of the smaller drainage valleys of Alaska
are impassible on account of the trees that have fallen from either bank and
interlaced their branches in the center. Dams are thus formed which favor
the increase of swamps. The growth of moss is thus promoted and the
difficulties of drainage still farther augmented.

The mossy covering of Alaska decreases in thickness towards the east, and
at the head-waters of the Yukon in the North West Territory it is not
especially remarkable. In southern Alaska, at least from Juneau south-
ward, the mosses are wonderfully luxuriant, and although not generally
frozen, as in the region of the Lower Yukon, they thoroughly protect the
subjacent strata.

Decay of Rocks.

Geographical Distribution of Rock Decay. — The prevalence of residual
deposits resulting from the atmospheric decay of rocks in warm and humid
regions and their decrease in thickness and extent in the colder and more
arid portions of the earth's surface has been discussed by me in a previous
paper.* At the time the paper referred to was written but little informa-
tion was available concerning the condition of rock surfaces in high latitudes.
What is here presented in this connection may be considered as a supple-
ment to the paper just mentioned and as sustaining in a marked manner the
conclusion that rock decay is a function of existing climatic conditions, and
in general decreases from tropical to arctic regions.

The conditious for noting the effects of a rigorous climate on rock surfaces
are especially favorable in Alaska, for the reason, as will be explained on
pages 137-41, that a very large part of our northern territory was not occu-
pied by glaciers during the Pleistocene period. Hence a comparison of the
amount of alteration of the rock surfaces there found with the decayed sur-
faces of similar outcrops in the driftless area of the upper Mississippi valley
and in the nonglaciated portion of the Appalachian mountains would reveal

* U. S. Geological Survey, Bulletin No. 52, 1889.

l:;i I. c. RUSSELL URFACE GEOLOGY OF A.LASKA.

the influence of existiiiLT climatic conditions on the decomposition of rocks
throughout a wide range of latitude.

i of jirniioiui'-'.'d Rock Droti/ in .l/./.s//. — The slight alteration that
the surface ruck- in the uonglaciated region of Alaska have suffered, is shown
by their freshness, wherever exposed, and hy the total absence of residual
clays like those which form such a conspicuous feature of many portions of
temperate and tropical countries. Nowhere in Alaska did I see more than
a trace of the red and yellow clays which result from the atmospheric decay
of a great variety of rock.-.

( >n Onalaska island the evidences of a general glaciation are absent, but
a great extension of local ice streams took place during the Pleistocene
period, and resulted in the removal of much of the previously accumulated
superficial debris. The ahseuce of marked alteration in the surface outcrops
and the lack of brilliantly colored clays might, therefore, in this instance be
accounted for by glacial action.

My observations were continued at St. Michaels, however, and all the way
up the Yukon to the eastern border of the uonglaciated area near the mouth
of Big Salmon river, and also for about 200 miles up Porcupine river.
Throughout this entire region there is a marked absence of pronounced
chemical alteration in the rock surfaces. This statement applies to rocks of
many kind-, including limestones, sandstones, granites, and various volcanic
locks. Moreover, there is practically an entire absence of residual clays.
The colors one sees in the rocks are usually various tone- of gray ami brown.
The brilliant colors due to oxidation of iron, SO prevalent in regions of
marked subaerial decay, are absent.

( 'omp orison vilh other Regions. — Rock decay in tropical countries is
known to lie -reat, as has been shown in the memoir already referred to. In
the southern Appalachians the brilliantly colored residual clays frequently
have a depth of more than a hundred feet over great area-. In the driftless
area of the upper Mississippi valley, a- shown by < !hamberlin and Salisbury,
the residual deposits have an average depth of about seven feet, with a max-
imum thickness of possibly ten time.- the average. In the driftless area of
Alaska, which extends north of the Arctic circle and probably reaches the
Arctic ocean, residual deposits, a- already stated, are absent

Observations in the United States alone thus extend over fully forty de-
of latitude, and prove thai rock decaj is a direct result of existing
climatic conditions. The elements of climate which exert the greatest influ-
ence on exposed rock surfaces seem to lie temperature and moisture. Rocks
decay most rapidly in waii 1 1 regions, where the rainfall is abundant, and are

ireely ;it all decayed in arid >.r frigid regions.

, Rep . 1--1 SB, Washington, lit

Disintegration of Rocks,
geographical distribution of rock disintegration.

Observations over very wide areas have shown that while rock decay ;s
most pronounced in warm and moist regions, rock disintegration, accom-
panied by the formation of talus slopes and alluvial cones, is most energetic
in arid regions and in northern latitudes — that is, where great variations of
temperature occur. High mountain tops in all lands are especially exposed
to the influences which promote rock disintegration.

The general absence of great accumulations of shattered rocks in warm,
humid regions is undoubtedly due to a great extent to the rapid decay of
rock surfaces, but still the generalization that rocks disintegrate most rapidly
in regions where great variation of temperature takes place is abundantly
sustained by observation.

In an arid region there is generally a great change in temperature between
day and night and between winter and summer, and, besides, both rock decay
and stream erosion are retarded. In consequence, subaerial deposits occur
in such situations on a scale that is unparalleled in more humid lands.

In high latitudes the great variation in temperature from season to season
promotes the disintegration of rock surfaces, while the low mean annual
temperature retards decay. The rank vegetation covering large portions of
northern countries and the prevalence of frozen soils and subsoils retard
erosion and favor the accumulation of debris. Hence the records of rock
disintegration on a vast scale are to be expected in all northern regions
where recent glaciation has not taken place.

OBSERVATIONS IN ALASKA.

Debris Streams. — Streams of loose, angular debris occur in very many of
the high-grade gorges on steep mountain slopes throughout Alaska. These
streams of loose stones are especially noticeable on the higher portions of
the steep mountain sides along the Yukon. They are lighter-colored than
the adjoining moss and lichen covered rocks, owing to the absence of all
vegetation upon them. Motion in these streams probably takes place prin-
cipally during the winter when they are covered with snow, or in the spring
when the snow is meltiug. Many of them are situated where snow accumu-
lates most abundantly, and occasionally originate snow-slides and avalancli
but the downward movement of the debris is probably due principally to the
slow settling or " creep" of deep snow on steep slopes.

In the glaciated region of southern Alaska, especially on the steep mount-
ain sides about the head of Lynn canal, streams of stones of the same char-
acter as those noticed in the Yukon region are a conspicuous feature in th<

(135)

136 1. <. RUSSELL — SURFACE GEOLOGY OF ALASKA.

wild landscape. Frequently a large de'bris stream will bifurcate above and
be joined by secondary branches, forming a dendritic Bystem of the same

ueral character a< that presented by high-grade mountain streams. In
fact, the depressions occupied by the debris streams are also lines of water
drainage, but the grade being exceedingly sleep, they discharge their waters
quickly, and are therefore usually dry. Their slopes arc usually upwards of
thirty degrees, and not infrequently appear to approach the perpendicular.
I have observed similar streams of d€bris on the steep mountains of the Arid
Region, hut they arc there less conspicuous — perhaps on account of the ab-
sence of a general covering of moss and lichens on the undisturbed rock
surfaci -

T'lhis Slopes "i- Screes. — All of the mountains in the nonglaciated portion
of Alaska arc flanked with great accumulations of angular d£bris derived
from the steep .-dupes above them. This material forms a pediment about
the mountains and accumulates especially in the mouths of steep gorges.
Many of the talus slopes are fed by the debris streams just described.

The limestone ranges along the Yukon near the international boundary
are particularly noticeable for the magnitude of the talus slopes about them.
While enjoying Mr. McGrath's hospitality, I climbed the mountains a few
miles north of his station, near Belle Isle, and had a tar-reaching view over the
surrounding country from an elevation of about .'>,000 feet above the river.
The crest of the range visited is composed of compact earthy limestone in nearly
vertical strata, striking nearly east ami west, conformably with the trend of the
mountains. This range retains its prominence for fully fifty miles eastward
of the national boundary and was in full view while suhsequentlyjourneying
up the Yulcm. Its crest is composed of blade like crags of rock forming an
exceedingly sharp crest line, flanked by vast slopes of loose angular stones
on either side. The rock is fresh and undecomposed, but everywhere
shattered and fissured. The upper portions of the talus slopes, like the crags
rising above them, are bare of vegetation. At a lower level they are covered
with moss, increasing in thickness as one descends, and finally, at an eleva-
tion of about 2,000 feet above the river, merging with the nearly universal
forest covering of the count ry.

The e litions just described prevail throughout the nonglaciated portions

of Alaska and the North West Territory, hut not in the recently glaciated
area of tin- upper Yukon region.

Absenct ofDibrisin tin Glaciated Region. — In the glaciated region drained
by the Lewes, and also throughout southern Alaska, there is a remarkable
absence of de'bris on the mountains, It is evident that the ice movement in
this region -wept the surface clear of previously accumulated fragmental
material. < Mi i he south Bide of the Coast mountains the d£bris carried away
by the ice was deposited in lie- ocean ; on the north Bide the ice movement was

RAPIDITY OF ROCK DISINTEGRATION. L37

a little west of north and the glaciers ended before reaching the sea. Where
these glaciers deposited their morainal material has not been determined.

The debris streams and accompanying talus slopes on the steep mountains
about Lynn canal, mentioned on page 135, record the amount of disintegra-
tion that has taken place since the retreat of the ancient glaciers.

Amount of Disintegration. — It is difficult to even roughly estimate the
amount of disintegrated rock about the bases of the mountains of Alaska, in-
to compare it with similar accumulations elsewhere. It is my judgment
however, based upon personal observations, that the extent to which the
rocks of Alaska have been disintegrated is greater than that of the mountains
of Colorado or of the southern Appalachians, but less than that of the
Great Basin region. The vast alluvial cones of Nevada and southeastern
California are unrivalled by anything of a similar nature that fell under my
notice in Alaska.

Glaciation.
previous explorations.

The Yukon region from St. Michaels to Fort Yukon was examined by
W. H. Dall* in 1867. In the brief published account of the geological
results of this exploration it is stated that there is an absence of all evidence
of glaciation in the country examined. In a later publication Dall f remarks
on the absence of glacial records on the west coast of Alaska north of St.
Michaels, and states that the absence of bowlders in that region had been
previously noted by Franklin and Beechey.

In 1881 John Muir accompanied the revenue steamer "Thomas Corwin "
during her voyage to Behring sea and the Arctic ocean, touching atUnalaska
and at several points on the west coast of Alaska, besides skirting the Siberian
coast from the Gulf of Anadyr to North cape. He also visited several of
the islands in Behring sea and the Arctic ocean. The geological results of
this voyage are presented in a paper " On the glaciation of the Arctic and
sub-Arctic region visited by the U. S. Steamer Corwin in the year 1881." X

In this report it is claimed that sufficient proof is presented to show that
the entire Behring sea region was occupied by a vast continental glacier
during the glacial epoch, and that the ice flowed southward across the
Aleutian islands and discharged into the Pacific ocean. I have examined
two of the- localities visited by Muir, as elsewhere stated, and at eaeh of
them I looked for and failed to find any evidence to sustain his general-
ization.

* Am. Jour. Sci., 2nd Ser., Vol. 45, 1868, p. 99. See also Observations od the Geology of Alaska, in
Coast Pilot of Alaska, First part, by George Davidson. U. 8. Coast Survey, Washington, 18<
195-196.

t Bull. Philosophical Soc. of Washington, Vol. 0, 1884, p. 34.

t In report of the cruise of the U. S. Revenue .Steamer Thomas Corwin in the Arctic Oc
by Capt. C. L. Hooper. Treasury Department, Washington, 1884, pp. 135-147.

138 I. C. RUSSELl 1 RFAI I GEOLOGY OF ALASKA.

Dawson's report on an exploration in the Yukon district contains a

description of tin untry traversed by me from the mouth of Felly river

to Juneau, as already Btated. Dawson reports an absence of glacial records
along the Yukon I Telly) below the mouth of Big Salmon river, ami their
presence higher up in the Bame drainage system.

McConnell's observations on the glaciation of this region have already
been referred to. His conclusions were that there are no records of glacia-
tion along the Porcupine or along the Yukon below the neighborhood of
the month of Big Salmon river, but above that locality there are abundant
records of a northward (lowing ice sheet, as had been determined by Dawson.

The conclusions of Dawson and McConnell agree iu all essential partic-
ulars, and demonstrate that there is a great area to the north of the northern
limit of the Cordilleran glacier, as named by Dawson, which was not occupied
by iee (luring the Pleistocene.

My own conclusions accord with those just referred to. The central and
northern parts of Alaska, like a large portion of the North West Territory,
\\a- not. in my opinion, occupied by ice in recent geological times.

PERSONAL OBSERVATIONS.

Unalaska. — While at Iliuliuk I examined the neighboring region, and
looked especially for evidences of former glaciation. In this search I was
unsuccessful. I found neither glaciated surfaces, perched bowlders, moraines,
bowlder clays, nor any of the well-known records of ice action. The rugged
topography of Unalaska and neighboring islands is sufficient to show that
l his portion of the Aleutian chain has not been abraded by a great ice sheet.

In .-ailing along the shores of Unalaska and neighboring islands one sees
round-bottomed valleys opening to the sea. These valleys have the charac-
teristic cross-profile of glaciated troughs. On some of the higher peaks
there are cirques similar in every way to those so common about summits
that have been centres of ice accumulation. I examined one of these cirques
on the north side of Mount Wood.' some four miles south of Iliuliuk, and
at a heighl of about 2,000 feet, but found no evidence of excavation by
glacial ice. The cirque was partially filled with BUOW at the time, and this
may have concealed Btriated lock surfaces and moraines visible later in the
• ason.

The presence of glaciers on the side of Moun I Makooshin (Makushin), the
highest peak on the island, reported by T. A. Blake,1 together with the
indication of former local ice 3treams furnished by the 1 -shaped cafions and
the cirques just mentioned, suggest that local glaciers of large Bize, but of
the Alpine type, radiated from Unalaska during the glacial epoch.

ttnld Mt. Peak ' on 1 urvey Chart of Captain's Bay, 1876.

ipon the Geology of Alaska; In Ex. Doc. No 177, 40th Congrest I esaion, Hoi

; tatlVl -, V. -, pp, ;| 1

RUGGED AND CONFUSED TOPOGRAPHY. 139

There is an interesting feature in the contour of the mountains forming
the most conspicuous portion of Amaknak island, which may have some
connection with former glaciation. The lower slopes have a rounded and
flowing outline, due in part to their mossy covering, which is limited in the
upper portion of the mountain by an irregular scarp. Above the scarp the
mountain slopes are steeper and more angular than below. It may be that
the scarp referred to marks the upper limit of former glaciation. Another
suggestion is that it is an ancient sea-cliff. This record and suggestion is
made with the hope that some one having opportunity may be stimulated to
investigate the phenomena more fully*

From the summit of Mount Wood, mentioned above, a magnificent view
can be had on clear days of one of the most rugged landscapes that can well
be imagined. The impression that one receives from such a wide-reaching
view of Unalaska is that its topography is without system. The more one
studies the forms of the laud the stronger this impression becomes. The
island is without the orderly arrangement of valleys usually so characteristic
of well-drained districts in humid regions. There are bold cliffs and out-
standing buttes which bear evidence of orographic disturbances and of long
exposure. I was not able to detect auy evidence in the relief of the land of
the former presence of a general ice sheet, nor was I more successful in at-
tempting to trace the paths of ancient Alpine glaciers. The topography of
the island is chaotic. Ragged cliffs, shattered peaks, together with walls and
spires of naked rock, rise on every hand, but without orderly arrangement.

I suspect that the reason for the confused and exceptional character of
the topography is due in large part to the obstruction offered to erosion by
the mossy covering of the lower portions of the island. The rain that falls
in the region of the Aleutian islands and in Alaska generally partakes of
the character of " Scotch mists " rather than of tropical down-pours. This and
the fact that a very large part of the annual precipitation is in the form of
snow would indicate that the impact of rain drops, an important factor in
the erosion of many regions, is here reduced to a minimum.

From Mount Wood one sees the majestic snow-clad summit of Makooshin
against the western sky. Across Akutan pass, to the east, is another active
volcanic cone of surprising beauty, rising above the sea mist like a cone of
burnished silver far into the clear heavens. To the north of Captain s
harbor is the extinct volcanic crater known as Paistrakov, thesides of which
have scarcely been scored by erosion. These mountains, formed by volcanic

*It may be well in this connection to direct attention to certain oliscure jii<li.;lti;.n- of terraces
or sea-cliffs, at an elevation of fifteen hundre.i or two thousand feet, on a number ol the mountains
near the Yukon, below Nulato. None of these mountains have been closely exam id it I

impossible to state whether the indefinite lines which may indicate terraces are horizontal, or
whether they coincide in elevation. It is not safe to assume that they are terra "le

that they may indicate lines of structure or be due to landslides, rhe mountains are so situated
that they could not have retained a lake, and if water lines exist on them their origin must be
looked for in a submergence of the land.

XIX— Bull. Geol. Soc. Am., Vol. I, 1889.

1 III I. C. RUSSELL QRFACE GEOLOGY OF A.LASKA.

extrusion, arc the only ones thai seem familiar to my eve- in the Unalaska
landscape.

Many pages might be devoted to describing the .scenery of this region, and
ecially the magnificent elifls overlooking the sea, hut ray visit was too
hasty to admit of such study a< this subject demands.

The characteristics of the scenery about Iliuliuk, as it appears to an
observer on Mount Wood, have been graphically described by II. W. Elliott.*

•■ Turning right about and looking south, our eyes fall upon a radically different
landscape — a bewildering, labyrinthian maze of Oonalashkan mountain peak- and
ranges, rising in defiance to all law and order of position, with that lovely island-
studded water of the head to Captain's harbor in the foreground. Ridge after ridge-
Bummit after Bummit, fades out one behind the other into the oblivion of distance,
where the suggestion of a continuance to tlii- same wild interior is vividly made, in
spite of wreath- of fog and lines of snowy sheen, relieved so brightly by that greenish-
blue of the mosses and sphagnum in which they are set. A few pretty snow-buntings
flutter over the rocks to the leeward of our position ; their white, restless forms are
the only evidence or indication of animal life in our rugged vista of an Oonalashkan
interior."

To my mind it is plain that the scenery described by Elliott is incompati-
ble with Muir's hypothesis of a former ice sheet flowing southward over the
A leutian islands.

Absence of Clm-hil I}r<-<n-<1* about St. Michaels. — The region ahout St.
Michaels is so completely buried beneath tundra deposits that opportunities
for observing glacial records, if any exist, are rare. The stratum of blue
clay beneath the humus layer of the tundra, however, mentioned on page — ,
shows no evidence of glacial origin. The volcanic craters near at hand
which rise above the tundra still retain their characteristic forms, and are
without Btriation, perched bowlder.-, or other evidences of glacial action.

Absence of Glacial Records along the Yukon. — During the voyage up the
Yukon I looked attentively for evidences of glaciation, but saw no indication
of a former occupation of that region by ice until after passing the mouth
of Little Salmon river, in the North WV-t Territory, approximately in
latitude 62 N. Along the Yukon and the Lewes above this locality there
are abundant records of the former presence of a northward Mowing ice
die( t. The limit of the nonglaciated region on the Yukon has not been
definitely determined, but provisionally it may be taken as stated above.

A.long the Yukon from its mouth to where it is joined by the Little Salmon,

a distance of about 1,500 miles, there is an absence of striated rock Burfa
"perched bowlders", bowlder clay, moraines, and all other evidence of an
ice invasion. This aegative evidence i- corroborated by the presence, along

the river bin If- and OD the mountain-, of numerous pinnacle- ami spires due

to long-continued Bubae rial erosion, and by vast tains slopes about the steeper

< >i , irctio Province. New I |

DEARTH OF GLACIAL RECORDS IX ALASKA. Ill

escarpments, which, as shown by the nearly complete removal of such material
in the region occupied by the Cordilleran glacier, could not have retained
their characteristic shapes had they been subjected to glacial action.

Not only is there proof of the absence of a general ice sheet over the
greater part of the extensive region indicated above, but the mountains
seen from the Yukon, several of which are fully 4,000 feet in elevation, are
without evidence of local glaciation. There are no cirques about their
summits or wide canons with lateral or terminal moraines on their sides.
AH of the mountains here referred to are near, and some of them are north
of, the Arctic circle, yet they are now completely bare of snow throughout
the summer. This indicates that existing climatic conditions are analogous
to those prevailing in the same region during the glacial epoch.

Absence of Glacial Records along the Porcupine.— I saw no evidence of
glaciation along Porcupine river, and my observations in this matter agree
with McConnell's. At the highest point reached by me on the Porcupine
the hill-tops, having an elevation of about 400 feet above the river, were
covered with well-worn gravel. These are probably stream gravels, and
correspond to the high terraces observed in the upper portion of the Yukon
and along the Lewes.

The Snow Line. — It is stated in many works on geography that the lower
limit of perennial snow occurs at an elevation of about 18,000 feet in the
tropics, decreases in elevation towards the north and south, and reaches sea
level in the antarctic and arctic regions. Alaska and the North West
Territory offer marked exceptions to this supposed rule. The snow line in
southern Alaska is at an elevation of about 3,000 feet, and increases in
height towards the north. John Muir* says —

" There is no line of perpetual snow on any portion of the arctic region known to
explorers. The snow disappears every summer not only from the low sandy shores
and boggy tundras but also from the tops of the mountains and all the upper slopes
and valleys with the exception of small patches of drifts and avalanche-heaps hardly
noticeable in general views. But though nowhere excessively deep or permanent,
the snow-mantle is universal during winter, and the plants are solidly frozen and
buried for nearly three-fourths of the year."

GLACIATION IN THE UPPER YUKON REGION.

Previous Explorations.— -The glaciation of the region drained by the head-
waters of the Yukon has been described by Dawson and McConnell, as
already stated.

The records of ice action in this region are smoothed, polished, and striated
rock surfaces, perched bowlders, and deposits of bowlder clay. Distinct and
well-defined moraines have not been observed, and the country generally is

* Botanical Notes on Alaska, in Cruise of the Revenue-Steamer Corwin in Alaska and the N. W
Arctic Ocean in 1881. Treasury Department, Washington, 18813, p. 17.

1 l'_' I. <\ Kl'SSEM I'KFACl GEOLOGY O] VLASKA,

tarkably fi material of any kind, except in the b ittoms <>f

the valleys, when t-borne gravels, river terraces, and lacustral Biltsare

abundant.

It . ;n desirabli the glacial phenomena of this region

in detail, since this would necessitate a repetition of whal has been recorded
in many other similar areas. Brief notic me of the most interesting

ion, however, may not b< t of pla

/< ' - G -( »n the east side of Lake Leba

tli, ious rai rounded limestone domes, known as the Han-

k liill-. which have an approximate elevation <»t" si x or eight hundred feel
above the Ink-'. These hills have been intensely glaciated, especially on their

i them sid< •-. Their 'them Blopes are broken and rugged, showing unmis-

takably the directii f movement of the ancient ice sheet which remodeled

their forms « >n tin- nearly vertical precipices overlooking the lake there

locality, strongly drawn grooves, which ascend Blightly towards

the north — that i-. in the rlirecti in of ice movement. The upward tending

the lines amounts, perhaps, to two or three degn - The cause of their

abnormal was a projection or shoulder on the face of the cliff, at right

;in_ ral course and also at right angles to the direction of ice

movement, which acted as a dam to the ice current and caused it to rise in

• the obstruction. - Bel in the aide of the glacier moved

with the ice and left a record of their course on the cliff against which they

/ G /.' ■ >rds. — The Hancock hills are bare of debris,

■hi:.' an nal perched bowlder, and, what is more important, are

|i and smooth that they musl have been uncovered and exposed to the

since the ice left them. The surfaces of vertical walls, and

■ n the summits ■'!' the rounded d ■-. r-till retain the grooves and scratches

made by tin- ancient glacier. The surface polish of the limestone has dis-
a|>!» an d from the ii I situations, but disintegration has n« »t pr

i t'. obliterate, "i" even !>■ greatly obscure, the ice markinj
When nsider the severity of the climate i<< which these hills have

of the glacial records upon them is signiGcant

date of the glacial epoch. The rate at which the

known to crumble and decay in temperate lati-

tu tin more exposed portions of the Mam k hills

ial markings more than a few hundred years.
Apparently I if the region al t Lake Lebarge occurred hun-

I ll I v <•

I hlli A iin Rep I

BOWLDEE (LAY OF DOUBTFUL ORIGIN. 143

The freshness of glaciated surfaces in the North West Territory, in southern
Alaska, and in the High Sierra of California merits attention. It may be
suggested in this connection that the glaciers on the west coast of North
America were not contemporaneous with the Pleistocene glaciation of the
northeastern part of this continent, but of much later date.

Bowlder Clay. — In the valley of the Yukon, between Rink rapids and
Lake Lebarge, there is a deposit of bowlder clay some twenty-five to thirty
feet thick, exposed in the scarps of the terraces bordering the river. That
this is a true bowlder clay deposited by glaciers is accepted without question
by both Dawson and McConnell. It is a light-brown earthy deposit, quite
homogeneous in composition, but sometimes obscurely stratified, and con-
tains pebbles and bowlders, some of them striated, scattered abundantly
through it. It occurs just below a region that bears undisputable evidence
of ice occupation, and has unquestionably the characteristics of a true gla-
cial deposit. To doubt that it was deposited directly by glaciers may seem
hypercritical ; but there are good reasons for believing that a very similar
deposit is now forming in the Yukon and other northern rivers, owing to
the transportation and deposition of gravel and bowlders by river ice.

The bowlder clay along the Yukon is apparently confined to the river
valley and does not cover the adjacent hills. At least I could not satisfy
myself that it extends back from the river, as would be expected had it
been deposited by a broad ice sheet. The bowlder clay along the Yukon
occurs only below Lake Lebarge. Above that lake the lacustral deposits,
which are a continuation of these resting on the bowlder clay lower down
stream, have been dissected by the river to a depth of 150 feet or more, and
in some places, as at Miles canon, to the underlying rock without exposing a
substratum of bowlder clay. As this region bears evidence of intense glacia-
tion, it is to be expected that a bowlder clay should occur there also, if the
deposit lower down stream is directly of glacial origin.

The deposition of bowlder clay by northern rivers is referred to on page
120 of this paper, where the agency of ice in modifying river deposits is
discussed.

Direction of Ice Movement. — It has been determined by Dawson that the
main direction of ice movement in the upper Yukon region was about N.
8° W.* Local deflections conforming to the trend of the larger valleys have
been observed.

During my journey from Lake Lebarge to the summit of Chilkoot pass
abundant opportunity was offered to verify Dawson's conclusions. On cross-
ing Chilkoot pass, and subsequently while traversing Lynn canal and the
" Inland Passage " south of Juneau, the general direction of former ice move-

*Rep. Yukon District, loc. oit., 1887, p. 159b.

Ill I < 1:1 8SE1 l. 1 Rl V< l. GEOLOGY <H ALASKA.

menl was observed to I"- southward, as baa been Btated by several other
travelers. The coast ran-.- of Alaska was therefore a center of ice accumula-
tion during the < llacial epoch.

A' Limit o) • Uion. — The most northern locality at which glacial

furrows have been observed along the Yukon is about a mile below the
mouth of the L Bowlder day occurs some sixty or seventy miles lower

down the river and, if of true glacial origin, indicates that the oorth< rn
limit of the ancient glacier must have been approximately a little north of
latitude 62 . This is the limit assigned by McConnell. More detailed in-

stigation is needed, however, before the extent of the ancient glacier can
l>r definitely assigned. No terminal moraines marking the extent of the ice
invasion have been reported, and we are -till ignorant of the disposition <>f
the immense amount ot debris thai was removed .from the glaciated area.
Neither ha- a divisi fthe period ofglaciation been recognized.

Terraces.

Stn vm Terraces along the Yukon. — The first terrace observed in ascending
the Yukon is on the right bank of the river, a 1 tout thirty miles below Anvik.
At that locality there is a marly perpendicular escarpment about fifty feet
high, formed of sand and well-rounded stones that have been deposited
against the Bteep mountain Bide. The surface of the gravel <1<] •< .~i t tonus a

shelf which may be traced for a mile or i c

act - along this part of the river are ool common, owing, apparently,
to their having been removed by the erosion of the Btream. A.bove Anvik
they become more and more frequent, but do nol form a conspicuous feature
in the landscape until after passing the mouth of the Porcupine and approach-
ing the international boundary.

• M I I rath 'e station, near the international boundary, the elevation
of the highest U trace was determined by angulation to be 73 I feet above the
river. The terrace at this poinl i- nol Btronglj defined, but that it is a river

med t ■ certain. Its elevation Beems greater, however, than

i -• terraces Been either above or below the 1 ll-t meridian.
I m tin- boundary all the way up the Yukon to the mouth of the Lewes,
and up thi I. to Lake Lindemann, terraces are not only conspicuous

hut form an importaut element in the Bcenery of the region.
'I'le referred to are of two types : I • lake terraces, described

- in ad and (2 stream terraces. The stream terraces are

rable into two groups, a rock-cut terraces and I b I gravel terra* i

nol common along the Yukon, vel a few < spicu-

ved Their surfaces are usually covered with river-
that in - their true gem sis is obscure. \

STREAM TERRACES OF THE YUKON. 145

characteristic example of a rock-cut terrace occurs a few miles below the
international boundary. The rock is there a contorted slate and rises steeply
to an elevation of about 150 feet, where a broad terrace occurs, the surface
of which is covered by twenty to thirty feet of gravel. Back of the terrace
the mountain rises precipitously to a height of several hundred feet. - This
and other terraces of a similar character in the same general region show
that the Yukon at one time flowed in a comparatively broad valley, and
spread out characteristic flood-plain deposits. Subsequently it deepened its
channel and left portions of the bottom of its former rock-cut trough in the
form of a terrace on the mountain side.

Most of the terraces of the Yukon are of gravel, and show that a pre-
viously eroded valley was deeply filled with stream-borne material, and that
subsequently, owing to increased grade, or perhaps to a lessening of load,
the stream eroded a new channel, leaving portions of its flood-plain from
time to time as terraces along its borders. In places from five to six ter-
races may be easily recognized, and not infrequently followed continuously
for many miles. Where they have been cut away on one side of the valley,
they almost invariably appear on the opposite side. No opportunity was
afforded, however, for examining them in detail. The most interesting con-
tribution that I am enabled to offer concerning them is their increase in
elevation as one ascends the Yukon. From about fifty feet in height above
the river near Anvik, they increase to over 700 feet at the international
boundary. Above the boundary the highest terrace is, by estimate, about
400 feet above the river.

Volcanic Dust in Stream Terraces. — The scarps formed by the cutting away
of gravel terraces along the Yukon near the mouth of Pelly river, and at
many localities on the Lewes, exhibit a conspicuous white band, formed by
a stratum of volcanic dust from eight to twelve inches thick, which was
blown out of some volcano with great violence at a recent date, and deposited
over a very wide belt of country. This deposit has been described by
Dawson * and was also noticed by Schwatka. f

I was informed by Arthur Harper, one of the most observing and obliging
traders on the Yukon, that a stratum of material similar to the one in the
banks of the Yukon below the mouth of Pelly river was seen by him at
Belle Isle, and also at Fort Yukon. Frank Densmore, one of the most
experienced frontiersmen of Alaska, reports a similar deposit in the valley
of the Tenanah, some 200 miles above its mouth. These observations indi*
cate that the bed of volcanic dust, so conspicuously exposed along the upper
Yukon and the Lewes, occupies a belt of country fully 500 miles broad from
east to west.

* Rep. Yukon District, loc. cit., pp. 43b^6b.

t Along Alaska's Great River. New York, 18S5, p. 196.

lit', i.i. |;|'--l I I 1 I ; I \ < I (iEOLOCrt OF ALASKA.

\ nong the Dumeroua problems awaiting examination by observant trav-

rs in Alaska is the determination ol the i stent and source <>!' this deposit.

/• ■ / Th( level-topped bluff known as the" Palisades," below

the mouth of the Tan an ah, has already been mentioned. The Btrata forming
these bluffs ha i y appearance of being lacustral b< diments. The erosion

a Bt ream channel across the level plain formed by the bottom of the old
lake has lefl portions of it in the form of a broad terrace, bounded on one
side by th< river bank and <>n the opposite Bide by encircling hills.

This terrace appears level, but it is nol a lake terrace as thai term is usually

underel 1. neither i< it a stream terrace ; for convenience it may be termed

& plateau \\ the mouth of Pelly river a broad, nearly level lava

coulee has been cut by the Yukon and by the Pelly, and forms another
example of this kind of terrace.

'I'h.' I., wea between lakes Lebarge anil Marsh has excavated a deep
channel across a plain formed of the sediment of a post-glacial lake, described
below under the name of Lake Yukon, ami has hit a broad level area on
each Bide of its c turse Bimilar in every way t" the terrace of older date at
the Palisadi

Examples of plateau terraces air < imon in many other regions, ami the

nam.- here proposed may he found sufficiently convenient for adoption by
;_''■"! graphers who study the origin of topographic forms.

hah Terraces. — Horizontal terraces occur all about the borders of the
lakes drained by the I . -.at various elevations up to Beveral hundred feet.
These water lines were formed by an ancient lake which has m,w passed
away: or perhaps more correctly, has been drained sufficiently to become
divided into a number of independent water bodies, of which lakes Lebargi .
Marsh, Tagish, and Bennett arc the best -known exainplt

A- the ancient lake hd-c referred to will doubtless receive attention in the

future. I have proposed to name it after the river which drained it.

I. \k i Yukon.

/'■ 0 ervatione. — Numerous observations concerning the terraces

and sediments <>f Lake Yukon may !»• found in Dawson's report of a recon-
nou a tie Yukon district. The terraces were also noticed bySchwatka

while descending the Lew,- in 1883.1

/' m and Extent. The first evidence of the former existence of an an-
"ii the head-waters of the Yukon which one meets in ascending

that ri in the neighbor! I of the mouth of Little Salmon river.

Thence up to the mouth of the Lew,-, and up the Lew,- to Lake

p in.

THE EXTINCT LAKE YUKON. 147

Lindemann, either the terraces or the sediments of the old lake are con-
stantly in sight. The lake probably extended far up the Yukon above the
mouth of the Lewes, and perhaps occupied the valley about Teslin lake ; but
this region is as yet unexplored. It occupied the valley in which Lake
Lebarge is situated, and also filled Ogilvie and Richthofen valleys which
open from it on the west. It also extended some distance up the valley of
Tahk-heena river. Above Lake Lebarge it formed an extremely irregular
water body, which filled the valleys now occupied in part by lakes Marsh,
Tagish, Bennett, and Lindemann. An exteusion eastward into the long,
narrow valley of Atlin lake is suspected, but has not been proven by obser-
vation.

As will be seen from this brief description, Lake Yukon was extremely
irregular. It occupied a number of long, narrow valleys which chanced to
be connected and so situated as to be flooded by a single lake, having
a depth in the valley of Lake Lebarge of between five and six hundred feet.

From north to south, Lake Yukon was about 150 miles long. Its width
near Miles canon and in the valley of Lake Marsh was about teu miles. In
other valleys it was much narrower, and even at its highest stage must have
appeared as a broad, placid river. Its extent, as well as the date of its ex-
istence places it among the more important lakes which were formed at vari-
ous localities on this continent during or immediately following the glacial
epoch. Of these, the best known at present are lakes Agassiz, Bonneville,
and Lahontan.

Depth as shown by Terraces. — The highest of the horizontal water lines
above Lake Lebarge has been estimated by Dawson* to have an elevation
of 400 feet above the surface of the existing lake. My own estimates make
its elevation about 150 or 200 feet higher. The elevation of the surface of
Lake Yukon above the sea during its maximum expansion must, therefore,
have been between 2,500 and 2,700 feet ; the elevation of Lake Bennett being
taken at 2,150 as determined by Dawson.

Sediments. — The fine, light-colored, horizontally stratified sediments of
Lake Yukon are well exposed in the steep river bluffs and along the lake
shores, all the way from near the mouth of Little Salmon river to Lake
Bennett. Fine exposures fully two hundred feet thick are to be seen along
the Lewes between lakes Lebarge and Marsh. At Miles canon the lake
beds rest on a floor of lava which is now being cut by the stream. The
channel occupied by the river previous to the existence of the old lake was
re-occupied only in part after the lake was drained and a new channel exca-
vated. There is here a fine example of superimposed drainage.

Origin of the Lake. — The position of the outlet of Lake Yukon is as yet
uncertain. What held its waters in check also remains to be determined.

* Report on the Yukon District, loc. cit., p. 159b.
XX— Bui.i,. Geoi.. Soc. Am., Vol. 1, 1889.

1 I ^ i. i . RUSSEL1 L'RFAOE GEOLOGY OF ALASKA.

il explanations of the origin of the lake may be suggested, bul each

dditional Reld observations in order to prove or disprove it.

The first and least probable of these hypotheses is thai the drainage of the

Yukon was obstructed and dammed by the large lava flow al the mouth of

the Pellv. alone the border of which the river has excavated a recenl channel.

ither possible explanation is that moraines were deposited aboul the

northern border of the Cordilleran glacier, obstructing the drainage and

in:: origin to the lake when the glacial ice was melted. This supposition

finds some support in the approximate coincidence of the northern limit of

glaciation with the northern extension of the old lake.

Still another hypothesis is thai the weight of ice forming the great Cor-
dilleran glacier was sufficient to depress the earth's crust in the manner
suggested by Btudents of glaciation in other regions. As the ice retreated,
the depression thus originated was occupied by a lake, which was slowly
drained ;i< the channel of discharge was deepened or as the land regained its
former elevation. The observed increase in the elevation of the terraces of
the Yukon from mouth to source seems to be a direct and important con-
firmation of this hypothesis.

Km-i in'. Glacii R8.

Observations at Chilkoot Pass and about Limn Canal. — In describing the
nonglaciated condition of the Yukon region, it was mentioned that all
mountains in that region are now bare of snow in Bummer, and hence
arc without glaciers. Snov was absenl from all mountains -ecu during
my journey up the Yukon and Lewes until reaching Lake Bennett, when the
1 as! Range of southern Alaska came in sight.

In crossing Chilkoot pass I sav five or six small glaciers on the north
Blope of the range. Some of them were in cirques; others on the Bides of the
more lofty mountain -pin- along the crest of the range. 'Their lower limit
appeared to be about 3,000 feel above the sea. About Crater lake, snow-
banks and -one ice on the Bteej tuntain side extended down to the very

margin of the water. These accumulations, however, did uot have the

characteristics of true glaciers, ('rater lak scupies the bottom of an

immense amphitheatre, which was the source of a large glacier during quite
• nt times. Tl ds of ice action are to be seen every v here about the

■ and in the wild valley leading from it toward* Lake Lindemann. It
evident that a slight change of climatic condition-, favorable to the
umulatiou of -now, would reproduce the counterpart of the ancient glacier
which once tlo no the amphitheatre of < rater hike.

The weather was thick ami extremely unfavorable for observation during
my journey from Lake Lindemann to Lynn canal The only observations

LARGE NUMBERS OP LIVING GLACIERS. 149

of interest made during this portion of the trip were on the small size of the
glaciers on the north sides of the mountains in comparison with the great
extent of the ice fields on their southern slopes ; on the general absence of
debris from the surfaces of the ice streams on each side of the range, and on
the absence of conspicuous moraines from their sides and extremities.

In descending from Chilkoot pass to the head of Lynn canal, several
small glaciers were seen on either side of the deep canon-like valley through
which the Taiya river flows. The muddy condition of the streams tributary
to the main drainage line indicated that there were other glaciers on the
mountain above, which could not be seen from the bottom of the valley.

The glaciers seen on the precipitous sides of the Taiya valley present con-
siderable diversity. Some of them are in gorges and lateral valleys, but
others are on exposed slopes and form conspicuous prominences in the
contour of the mountain when seen from below. Some of them contract
gradually toward their lower extremities and end in tapering tongues of
ice ; others expand and form fan-shaped termini, after the manner of the
Rhone glacier; some of them have ice caves at their extremities, from which
torrents of turbid water rush down the rocky slope below ; others melt away
without forming these beautiful blue grottoes. As the glaciers are remark-
ably free from debris and have but slight morainal accumulations about
them, the variety they present near their lower extremities must be due
mainly to the relief of the cliffs and mountain slopes about them; yet it is
difficult to trace any connection between their diverse forms and their
environment.

From a mountain top about 3,000 feet high, on the west side of the valley
near the mouth of Taiya river, I obtained an extensive and most interesting
view of the extremely rugged country about the head of Lynn canal. The
glaciers in this region are small in comparison with those reported by various
travelers as existing on the seaward slope of the St. Elias range, but they
present great diversity, and some of them are sevei'al miles in length. The
more elevated portions of the mountains seen from my station, with the
exception of the more precipitous peaks aud crests, were covered with snow
and ice aud gave rise to a large number of ice streams. From one station
I counted nearly forty veritable glaciers ; a change of position of half a
mile brought others into view which before were concealed by the rugged
ciags and snow-covered slopes near at hand. The outlines of vast amphi-
theatres could be traced by lines of crags along their borders, but the de-
pressions themselves were filled nearly to the brim with ice. The ruggedness
of these great basins in the summits of the range, was so completely con-
cealed that a person could walk with ease from peak to peak across an ice-
held where a passage would be impossible should the ice be melted.

The present condition of the mountains of southern Alaska presents a

I . . . RUSSEL1 1 I ; I \ ' I GEOLOGY OF \ I V.SK A.

_'r:i|iliic picture of what must have existed in the Sierra N< vada and some
other -imilar ranges during the Glacial epoch. A careful study of whal is
now taking place in these ice-covered mountains would no doubt go far
toward explaining many of the records of glaciation found in regions where
glaciers do nol m>\\ exist.

The glacii about the head of Lynn canal, like those <>n the sid-

the valley of the Taiya, present great variety. Some of 1 1 1 « ■ larger amphi-
theatres are drained by veritable rivers of ice several miles in length, which
ive tributaries from neighboring slopes and lateral canons. Many oi
the ice ms specially those in the smaller cirques, are not drained by

well-defined ice streams, but like the secondary glaciers of the Alps, described
by Forbes, and the existing glaciers of the High Sierra of California, form
tongues of ice which have all the characteristics of the larger glaciers,
pting that topographic conditions limit their growth.

In some instances secondary glaciers of considerable Bize occur on steep
mountain slopes, without any indication of an amphitheatre or depression
beneath them. These ice bodies frequently appeal- as convexities on the
mountain Bide, fully exposed to the sky on all Bides. .Many of the neV<5 fields
about Lynn canal, as is common in all ice-covered mountains, are drained
by several glaciers. The icestreams flowing from Bnow-fields near the cresl
of the mountains in some instance a drain both north and south, and contrib-
ute on melting both to Taiya river, which reaches the sea within half a
dozen miles, and t « > 1 1 1 • - Yukon, the mouth of which is two thousand miles
away.

Above the snow-fields there are many spires and minarets of shattered
rock which hear no evidence of ice abrasion. These bold pinnacles occur

•ecially along the rims of ice-filled amphitheatres, and are ihe most prom-
inent where the walls of two or more depressions unite. The -pin- projecting
above the neve* are frequently bo slim and tapering that they look like tree
trunk- when viewed from the valley- below. The angular and unabraded

udition of the extreme summits of these mountains agrees with what may
In- Been ahum the mure lofty summits of the High Sierra, and illustrates still
farther what must have been the condition of that picturesque region at the
time it was Bhrouded in glacial ice.

One of the most Btriking features of the high, ice covered region of south-
\ ii i- furnished by the clouds and vapor-wreaths that nearly always

• n< ii < ii- the i n tain-, or rise mill- in height above them. Even on bright

sunny days, when thi - clear and blue, the moisture borne upwards by

the warm aii m the valleys i- cundeii-cd and forms cloud-maSSi

which roll upwards with fleecy whiteness like thunder-cape in temperate
latitude! I forme of these vapor-wreaths and the blue

-had- i on the Bnow imparl estion of life and motion to the

THE LUXURIANT LOWLAND FLORA. 151

frozen landscape, the charm of which is beyond description. All of the
higher summits and ice-bound plateaus are above the upper limit of tree
growth, but the ice streams descend far into the forested region, and many
of the larger glaciers end in dense groves of spruce and hemlock.

In the valley of the Taiya the timber line is sharply drawn along the bor-
dering cliffs at an elevation of about twenty -five hundred feet. Above that
height the mountain sides are stern and rugged ; below is a dense forest of
gigantic hemlocks, festooned with long streamers of moss, which grows even
more luxuriantly than on the oaks of Florida. The ground beneath the
trees and the fallen monarchs of the forest are densely covered with a soft,
feathery carpet of mosses, lichens, and ferns of all possible tints of brown
and green. The day I traversed this enchanted valley was bright and sunny
in the upper regions, but the valley was filled with drifting vapor. At one
minute nothing would be visible but the somber forest through which the
white mist was hurrying ; and the next, the veil would be swept aside, reveal-
ing with startling distinctness the towering mountain spires, snowy pinnacles,
and turquoise cliffs of ice towering heavenward. These views through the
cloud rifts seemed glimpses of another world-. Below was a sea of surging
branches that filled all the valley bottom and dashed high on the bordering
cliffs. Much space could be occupied with descriptions of the magnificent
scenery about Lynn canal, and of the wonderful atmospheric effects to be
seen there ; but the poetry of travel is foreign to these pages, and must be
left for more facile pens.

Absence of Debris on the Glaciers. — One of the most noticeable features of
the glaciers about Lynn canal, and, in fact, of all of the glaciers that I have
seen in Alaska, is their general freedom from debris and the small size of the
moraines that are being formed about them. At times faint medial moraines
may be seen upon them, especially when viewed from a distance ; but in all
cases these are composed of small stones and dirt, and do not contribute to
the formation of conspicuous terminals at the extremities of the glaciers.

The glaciers about Lynn canal are without the convexity of surface so
pronounced in many Swiss glaciers. This is seemingly accounted for by the
fact that they are remarkably free from debris, and hence equally exposed
in all parts to the heat of the sun. In some instances, where the glaciers
could be seen from below projected against the sky, they appeared even
slightly concave in cross profile.

In continuing my journey down Lynn canal, I visited the Davidson gla-
cier, and also saw the Eagle, Lemon creek, and Juneau glaciers, and several
others scarcely less important but still unnamed. Many of these descend
practically to sea-level, although their extremities are commonly separated
from the water by morainal deposits half a mile or so in width. Their sur-
faces, like the surfaces of the glaciers examined near the head of the same
inlet, are remarkably free from debris, and terminate in a variety of ways.

[52 I. '. RUSSEL1 I'RFACE GEOLOGY OF ALASKA.

/ / I . i\ instance where well-defined ice streams

i from lateral cafiona into broad valleys, and con-

uently are u neon fined by tin- neighboring mountain slopes, they expand
in all directions so as to form fan-shaped or semicircular termini, Bimilar to

the delta-like terminus of the Rhone glacier. This expansi f glacial ice,

when ii"t encumbered l>y moraines and free to move in all directions, tat
place apparently without reference to the direction in which the glaciers
flow. The Davidson glacier furnishes a typical example of the phenomenon
li,-i red i". In the lower part of the gorge through which ii descends,

it flows a littl if north. Another example, equally typical, occurs in

a valley tributary to Taiya valley, immediately smith of Mt. Emmons. This
glacier flows aboul Bouthwesl down a lateral gorge and enters a broader
valley nearly at right angles. Like the Davidson glacier, it endsin a Dearly
symmetrical fan-shaped terminus. A third example of the same character
is furnished by the Nor ris glacier of Taku inlet, some fifteen miles east of
Juneau. This glacier, I am informed, flows about southeast and ends in a
fan-shaped ice-foot, as is well Bhown in an illustration recently published by
6. I Wright.* The absence of d6bris on the surface of this glacier is
indicated in that illustration.

These and other examples thai might be cited seem sufficient proof that
Alpine glaciers, when unencumbered by moraines, expand in all directions
without nt'. rence to their direction of movement, and form characteristic
fan-shaped termini of the Rhone -lacier type when they advance on to a

plain.

// of Glaciers about Limn Canal. — The presence of bare fields of

dlbris about the extremities of many of the glaciers in the neighborhood of
Lynn canal, indicate that the ice streams of that region are receding. This is
well illustrated by the bare and rugged piles of fine debris which encircle the
expanded foot of the Davidson glacier. Several cirques and steep glaciated
troughs in the sai ion, and also at various points farther south along

the" Inland Passage," which are ban of vegetation and have recently been

indoned by ice, bi timony in the Barae direction. The conclusion

that the glaci< ra of southern Alaska are retreating is in harmony with < i. I .

bservations on the recession of M uir glacier.*) This recession is

apparently a < tinuation of the general glacial retreat initiated when the

< lilleran r reached it- maximum expansion.

// ' I laska and accompanying Climatic Conditions. —

niiej the distribution of living glaciers in Alaska ami

their dependence on existing climatic conditions are so obvious that I venture

ii this connect ion.

mall II lua trail ( the

((LACTATION DUE TO LOCAL CLIMATE. L53

The absence of perennial snow on the mountains of the Yukon region has
already been referred to. A similar absence of snow has been reported by
McConnell along the lower McKenzie. The reader will recall also that the
glaciers on the north side of the Coast Range of Alaska are very much
smaller than, and do not descend nearly so far as, the glaciers on the south
side of the same range. Closely related to the distribution of the glaciers
are certain climatic phenomena.

In the Yukon region the winters are long and extremely cold ; a temper-
ature of minus 80° Fahrenheit, I have been informed, not being uncommon.
The mean annual temperature of this region as shown by Dall * is between
ten and twenty degrees Fahrenheit. The snow-fall, however, is not great ;
perhaps two or three feet, on an average. The summers, though short, are
pleasant, and hot enough to melt the winter's snows. The large number of
hours of suushine in summer greatly assists in raising the mean temperature
at that season.

Ou the southern coast the winters, though long, are not severe, a fall of
the thermometer to zero Fahrenheit, being seldom experienced at Juneau
or Sitka. The snow-fall is heavy on the mountains, and rain is abundant
on the immediate coast. The summers are cloudy and wet, with much fog;
the number of clear days being few. The mean annual temperature on the
coast as given by Dall* is in the neighborhood of forty degrees Fahrenheit.
The rainfall during the only year in which continuous observations were
made at Juneau was over 103 inches.f

These observations show that the abundant precipitation on the southern
coast of Alaska, accompanied by a low mean annual temperature (due es-
pecially to a cool and cloudy summer), has resulted in the formation of vast
ice-fields from which magnificent glaciers descend to the sea.

The excessively cold winters of the interior, followed by comparatively
clear and warm summers, are not accompanied by an accumulation of
perennial snow even on mountaius three to four thousand feet high and
situated under the Arctic circle.

The southern shore of Alaska rises from the ocean to a great height, and
furnishes a cold surface against which the warm, moist southeru winds im-
pinge and are forced upwards. These favorable conditions for the formation
of glaciers are still farther augmented by the presence of warm currents in
the Pacific. A vast evaporating surface and a cold condensing surface are
here close together.

The intimate dependence of the Alaskan glaciers on existing topographic
and climatic conditions suggests certain interesting hypotheses in reference
to the occurrence of continental glaciers in other regions and perhaps in
various geological epochs.

* Pacific Coast Pilot, second series, U. S. Coast and Geodetic Survey, Washington, 1879, pi. 20.
t MSS. of observations made by Karl Koehler from Nov. 1, 1883, to Nov. 1, 1884.

l.»l I. '. RUSSKL1 1 III \< i: GEOLOGY OF \LASKA.

A- previously stated, the freshm I aciated surfaces in the region occu-
pied by th<- Cordilleran glacier i- Buch as to indicate thai the great ice-field
of the northwest coast of this continent was of more recent date than ihc
Labrador ice-sheet. A study of the junction of those two great areas of
glaciation would I"- instructive, and might Bhow whether the ice records of
area overlap those of the otl

It" it ran In- > 1 1 . i w 11 that the various aria- of former glaciatian in the
northern hemisphere were not ■»<•*- 1 1 1 »i< -r l by ice at the same time, but had in-
dependenl histories, it is evident that the much-discussed question of the
cause "t- the glacial epoch would be greatly simplified. This is a difficult
proposition to demonstrate, but it seems to be the direction in which glacial
Btudies are leading

In Alaska there is a glacial area of the continental type in which the
maximum of ice occupation has passed, and the ice-sheet is fast retreating.
In Greenland there is another vast ana occupied by a glacier of the same
type which is apparently still increasing. In the northeastern states and
the adjacent portion of Canada, in northwestern Europe, and probably in
central Asia, continental glaciers existed at a recent date, but have dis-
appeared. A Btudy of what may be considered local conditions in th<
various areas Bhould show whether variations in ocean currents and land
elevation are capable of producing glaciers of the continental type. At
pi' -.'Hi tl bservations are insufficient for such comparative study.

The hypothesis thai continental glaciers, like those of the Alpine type,
are individually dependent on local climatic and geographic CMii.liii.in-, if
-ii -t a i he. 1, can be used in explaining the presence of glacial records in ancient
formations without invoking great revolutions in the earth or changes in its

smic relations. It' the extinct continental glaciers of the northern hemi-
sphere were not contemporaneous, it is apparent that we are now Living in
glacial epoch" as truly as was Pleistocene man. The [ce Vgi still
r- in Ala-ka, ami has not vet reached its maximum in Greenland.

W lshinoton, I » < '.. January 12, 1890.

DISCUSSION.

Professor N. S. Shaler : I should like to ask Mr. Russell if the facts
observed by him in Alaska are consistent with the supposition that the non-
glaciated portion of the country was beneath the level of the sea during the
glacial epoch '?

Mr. Russell: My observations do not favor such an hypothesis. Just
where the coast line was in Alaska during the glacial epoch remains to be
determined.

President T. C. Chamberlin : I should like to inquire as to the relative
age of the glaciation. Is it young or old?

Mr. Russell: The records are extremely fresh. On limestone hills near
Lake Lebarge, which could not have been protected by superficial deposits
since the glaciers retreated, fine striations still remain. The glaciation is
perhaps fresher in appearance than it is in the Sierra Nevada mountains.

President Chamberlin : The observations of Mr. Russell have a very
important bearing on our general conceptions of the Pleistocene period,
especially as to its great agency. It seems that we can now safely say that
this agency was excluded from the northwestern corner of our continent. It
also appears from evidence from Siberia that glaciers may be excluded from
that still more extended region ; for, while there are evidences of glaciation
in the mountains on the southern border of Siberia, it does not appear that
the extent there was more than would be accounted for by a slight increase
in the precipitation of that region. The Pleistocene glaciation gathered
about the north Atlantic, while the region of the north Pacific was free from it.

Professor Shaler : I am very glad to testify along with the last speaker
as to the importance of these observations. I think they enable us to bring
the glacial question — the question of the last glacial period — down to a very
simple issue. I think I could safely undertake to re-create a glacial period
in this part of the continent, if we could only manage the rainfall, leaving
the temperature as it is. We have, for instance, at Mount Washington the
conditions which just approach glaciation. I am inclined to think if the
average rainfall there were twelve inches greater than at present, that
amount coming in the form of snow, we would be likely to have a small
glacial cap on the top of the mountain. Such an ice-cap would breed its
own climate. A considerable increase of the snow-fall in New England
would, I think, most likely set up glaciation over a large part of its surface.

President Chamberlin: Coincident with this limitation in distribution,
we are approaching a demonstration — if we have not already reached it —
that in the first glacial epoch pre-eminently, and in the second glacial
epoch measurably, there was a low condition of the surface; and the old

XXI— Bun. Gf.ol. Soc. Am., Vol. 1, 1889. (155

156 l. «. RUSSEL1 CTRPACE GEOLOGY OF ALASKA.

doctrine of a northern elevation as a cause of glaciation seems to be excluded
by present disclosures. It Beema t" me that by the above line of observa-
tion we have almost excluded extra-terrestrial causes, and by the demon-
stration of the lower altitude of the surface we have excluded those causes
that were relied upon by Lyell and others in the earlier days. Ii Beems to
tin-, further, that it is impossible t<> account for the glacial period by any
Bupposable change in precipitation. We have, in the north Pacific regioni
:it the present time, the most extraordinary precipitation, and yet we find
that these Ala.-kan mountains are not the centers from which extensive ltIu-
ciation radiates. I therefore find very grave difficulties in connecting the
former glaciation with any climatological change that can be supposed to
have taken place with the earth's axis of rotation where it now is.

INDEX.

Page

Alaska Commercial Company, Courtesy of 103

Aleutian islands, Glaciation of 134,137, 138-140

Amaknak island, Topography of 139

Andreieffski, Breadth of river at 112

— , Forested region begins at Ill

Anvik, Terrace along the Yukon below 144

Aphoon branch of Yukon, Breadth of 112

Asia, Probable relation of mammoth to glaciation in 123, 124

A-tlin lake, Suggested survey of pass leading to 103

Baer, K. E. Von, Cited on the depth of frost in Siberia 130

Banks of the Yukon, Description of 112-115

Beauchrf.au, J 103

Beeciiey, Captain, Cited on absence of bowlders on shore of Behring sea 137

, Reference to description of ice-cliffs by 127

Behring, Various ways of spelling the name 101

— sea, Sources of drift-wood in Ill

Belle Isle, Talus slopes on mountains near 163

, Volcanic dust reported near 145

"Bertha", Sailing of 101

Blake, T. H., Cited on glaciers on Mt. Makooshin 138

Bluffs on the upper Yukon, Brief description of. 109-110

Boonton, N, J., Reference to fossil fishes near 124

Bowlder clay along the Yukon, Description of 143

" Bowlder clay" deposited by rivers 120

Cantwell, J. C, Cited on ice-cliffs of Kowak river 127

Captain's harbor, Unalaska, Scenery about 139-140

Chamherlin, T. C, Cited on the decay of rocks in the Mississippi valley 134

— , Cited on glacial grooves 142

— , Discussion by 155-156

Chilkat pass, Suggested survey of. 103

Ciiilkoot pass, Crossing of 102

, Direction of ice movement near 143

, Existing glaciers near 148-149

, Suggested survey of 103

Climate in relation to distribution of existing glaciers 152-156

Coal, A possible explanation of the origin of 127-128

Coast Survey, U. S., Expedition fitted out by 101

Cordilleran glacier, Absence of debris in region occupied by 141

, Relative age of 154

Crater lake, Snow banks and glaciers near 148

Cromier, F 103

Dall, W. H., Cited on the mean annual temperature of Alaska 153

— , Mention of 126

— , Nomenclature of the Yukon discussed by 104

— , Observations of, on absence of glacial records on Behiing sea and the Yukon 137

— , Region explored by, in Alaska 102

— , Reference to description of ice-cliffs by 127

Davidson glacier, Fan-shaped terminal of 152

, Moraines about the foot of 152

, Visit to 151

Dawson, G. M., Cited on character of water of the Lewes and Tes lin-too 115

bowlder clay along the Yukon 143

the character of the Lewes and Tes-lin-too 106

direction of ice movement in the upper Yukon region 143

volcanic dust in stream terraces 145

the glaciation of the upper Yukon region 138, 141

the terraces of Lake Yukon 146

— , Nomenclature of the Yukon discussed by 104

— , Region explored by 102

Delta of the Taiya, Fish remains deposited in 124

(157)

L58 I. C. RUSSELL L'RFACE GEOLOCi OF ALASKA.

■ r the Yuki '-''

, Drift timber in 110-111

. General c f 110,111-112

f lli:i

inic dual "ii the Tartarian 148

• i»t Nulato and Forty-mile creek

in Siberia 1:!"

in thi

tip tratam beneath the moss 129-130

:', on the ithern U&<*ka ,:,,

. in • -i of the Yukon region ' ;'

iption "f ' ■ ' ■'■'■

Dip Jong 1 1 1 » - lower Yukon '"s

hi. ii "f rocks 133-134

, \ l decay in Alaska ,:{''

, Com] ■ i regions 184-188

, GeonrRpliicul distribution "f ,:,:1 ' ■'

DlBTH ION ol - 138-137

Distahi i traveled '"

In; in timber in the delta of the Yukon 110-111

, Volcanic, In Alaska and the North West Territory I ' ■

i 1 glacier, Mention of. '•''

Elliott, H. W., Cited on the topography of Unalaska island. ] '"

,\, \ . inference i ktiona "i> depth of fn>«t in Siberia, by 1:!"

of riulit bank <>f Yukon 11-'

— retarded by mosa 132-133

Bscbscboltz bay, Depth of frozen tundra al '-■

. . International boundary '"'

I'm i i- in the Yukon region I"s

Plan ren of '-'

Kim fntoBRS (Rink Rapids), Mention <>( '-'"'

,.-ii m\ deposits "ii the Porcupine, Desci 1 120-122

i. 1 1., Cited "ii '!"■ " Becondarj glaciers of the Alps 160

i -i i Miih, Departure from '"-

tTT-mLBC er of rocks at mouth of 116

1 Depth offrosen stratum on '■ '

, Rocks in banks "f Yukon near ""

arrival nt '"'

. I Ime Bpenl al '"-

t Volcanic dust n • >ar ' ' ■

! leptb "f. nt Nulato and Forty-mile creek

, Ht st. Michaels IJ'

. ia

, in thp arctic regions, discussed by R. B. Woodward

ilogical agent ' '■-'

■ .ii along the Porcupine, Mention "f 121

el sound, Depth of ' -~

of bowlders on shore of Behring sea 137

■ nuatlon "t. In Alaska and Greenland ' ■'

' '-

, 1, In'the upper Yukon region 143

_,. >f n' l,;

' '" '"

■ii "8 '"

' |s

' "

long tio- Yukon i > 139, I4fl 141

i ,:i" 188,141 142

_, rn North \ • • » - i oa 163 164

■

' '"

— . Pan-«ha| ■

— , i on In North

INDEX.

1.7.1

Page

Glaciers in Alaska, Distribution of 152

— , Relation of, to distribution of mammoth remains 123

— in Siberia, Probable relation of, to mammoth remains 123

— of southern Alaska, Relation of, to existing climatic conditions 152-153

— of southern Alaska, General absence of debris on 151

"G. W. Elder", Passage in 102

Greenland, Glaciers of 154

Hancock hills, Glaciation of 142-143

Harper, A., Cited on volcanic dust along the Yukon 145

Highlands of the upper Yukon, Character of 114-115

Hooper, C. L., Cited on the origin of clear ice in the tundra 128

— , Reference to description of ice-cliffs by 127

— , Reference to description of the tundra by 125

— , Reference to observations on depth of frozen soil 130

Ice Age, Continuation of, in Alaska and Greenland 154

Ice in the tundra, Explanation of the origin of 128-129

— movement, Direction of, in the upper Yukon region 143

Ii.iuliuk, Arrival at 101

— , Character of vegetation near 126

— , Scenery near 139-140

Joint-valleys in the bluffs of the lower Yukon 109

Juneau, Arrival at 102

— , Climate of 153

— , Direction of ice movement near 143

— , Mention of 102

— glacier, Mention of 151

Kochler, K., Meteorological observations by 153

Kotzebue, O. Von, Reference to description of ice-cliffs by 121

Kotzebue sound, Depth of frozen strata near 127

Kowak river, Mention of ice-cliffs on 127

Koyukuk river, Character of banks of the Yukon near 112

Kuskowim river, Drift-wood of Ill

Labrador glacier, Relative age of 154

Lake, A-tlin, Suggested survey of pass leading to 103

— , Crater not the source of the Yukon 105, 107

, Snow banks and glaciers near 148

— Bennett, Mention of 102

, Turbidity of water of 116

— Lebarge, Direction of ice movement near 142, 143

, Mention of 102

, Mention of glacial evidence near 115

— — , Source of sediment in 116

, Upward deflection of glacial grooves near 142

— Lindeman, Glacial records near 148

, Mention of 102

not the source of the Yukon 105

, Terraces near 144

, Turbidity of the water of 116

— Marsh, Turbidity of the water of .' 116

— Nares, Mention of 102

— Tagish, Mention of 102

, Suggested survey of pass leading to 103

— Teslin, Source of the Yukon near 107

— Tagish, Turbidity of the water of 116

— terraces along the Lewes 146

— Yukon, Description of 146-148

Lakes on the tundra, Character and origin of 128

Lariviere, H 103

Lemon creek glacier. Mention of 151

Lewes river. Arrival at mouth of 102

included under the name Yukon 105, 108

, Measurements of volume of 106, 107

lt'.ll i. .. RUSSELL 1 i:i \< I- GEOLOGY OF ALASKA.

Page

Li ■ I "

I.i! - iern boun ted area near 140

l..nhi, M ml in the Yuk"ii .it 116

Lowed Ram ■ of 112

, M Yukou oear 116

in Lank- of Yukon at 122

Rampart er and discussion of the origin of U'_'-il4

I.imi.i , Ri Q Boils ISO

l.iw canal, I '"-'

. Direction of ice movement near 143

, Kxi-ti ir 148-149

,01 u "ii the - ii

itedsurvi 103

— - »r the head of 149

i the extinction "f 123-124

— remains in the banks of the Yukon 122-123

, Relation t" the distributi f glaciers 123

Hi ' «owKi ii, I i "ii the absence of perenni ilong t lie McEenzie

bowlder clay along the Yukon 143

■ ation of the upper Yukon region 13*. i n

the northern limit of glaciation im the Yukou 144

explored by

• ; \ i ii, J. E., arrival at station "f, on the Yukon 109

— , I of 103

— . of boundary survey i"i

McG i, Beight "f terrace near 144

-"ii mountains near 166

Mxloikakat, Faults near 108

Mil an of the Yukon above 126

Mil i";

s m « in the Yukon region 108

portion of Alaska l £1-133

Mi. ! an-sha] terminal "f glacier near 162

M 1. Wood, Unalaska, Amphitheater on the north Bide "t 138

. - Ut 131I-14U

Ml ! 162

M 111:. 1 glaciation of the region about Behrl 181

a arctic regions 111

— , ! in of tundra by i-">

a the origin of clear ice in the tumlra 12£

f l-''

. ik 1 n of the abundant fish remains In 184

104-108

1 terminal "f 1 -

emaic lear 122

diment in the Yukon at 116

: immotb remains Dear 122

• 1. ink- of the YukoD Dear 112

108

— , r "ut in the Yukon at 116

1 11 tai ii- near

I'M 122 1 - '.

. Mammoth 182

• 103

1 1 •

: ... . loj

— - ill

lor the 1 LOS, 10M

b the " '> 124

INDEX. 161

Page

Peterson, C, Cited on character of strata at the Palisades 123

— , Navigation of the Yukon by 124-125

Plateau terraces along the Yukon, Description of 110

Porcupine river, Absence of decayed rocks on 131

, Absence of glacial records along 141

, Ascent of, by the steamboat "Yukon " 124

, Date of journey on 102

, Flood-plain deposits of 120-122

, Descent of, by McConnell 102

, Journey stopped by low water on the 102

, Records made by river ice on banks of 120-12:

Port Townsend, Mention of 102

Pyramid Mt. Peak, Unalaska, Amphitheater on north side of \ 138

, Scenery about 139-140

Rampart House, Navigation of the Porcupine river near 124

Richardson, J , Reference to observations on frozen soil in North America 130

Rink rapids, Difficulty of navigation at 125

Russell, I. C, Discussion by 155

Salisbury, R. D., Cited on the decay of rocks in the Mississippi valley 134

Salmon, Possible preservation of 124

Schwatka, F., Cited on the terraces of Lake Yukon 146

— , Cited on volcanic dust along the Lewes 145

— , Nomenclature of 105

Screes or talus slopes, Descriptions of 163

Section of flood-plain deposits along the Porcupine 122

Sediment in the Yukon, Measurement of 116

— of Lake Yukon 147

Shaler, N. S., Discussion by 155

Siberia, Depth of frozen stratum in 130

— , Probable relation of mammoth to former glaciation in 123, 124

— , Remarks on the glaciation of 155

— , Visited by John Muir 137

Sitka, Climate of 153

Slates, Contorted, on the Yukon and Porcupine rivers lon-lio

Snow, Absence of, on the mountains of northern Alaska 14s

Snow line, Elevation of, in Alaska 141

St. Elias range, Comparative size of glaciers on north and south sides of 140

St. Michaels, Absence of decayed rocks at 134

— , Absence of glacial records near 140

— , Arrival at 101

— , Character of the tundra near 120

— , Depth of frozen stratum at 126

— , Depth of humus layer near 127

— , Drift-wood obtained at Ill

"St. Paul ".Sailing of 101

Strike of rocks along the lower Yukon 108

Stream terraces along the Yukon 144-145

Structure of the Yukon region 108-110

Surveys suggested 103

Tahk-heena river, Character of the water of 115, 116

, Mention of 103

, Source of the sediment of 116

Taiya river, Migration of salmon in 124

— valley, Fan-shaped terminal of glacier near 152

, Glaciers on the sides of 147

Tako arm of Tagish lake, Suggested survey of pass leading to 103

Taku inlet, Fan-shaped terminal of glacier in 152

, Mention of 103

— pass, Suggested survey of 103

Talus slopes or screes, Description of 163

Tananah river, Character of the water of 115-116

, Volcanic dust reported near 145

Terraces along the Yukon, Description of 144-146

ILL' I. c. RUSSELL [TRFACE GEOLOGY OF ALASKA.

Page

Tebracbs, CI i : '"

— , Obscure,! 136

f Luke Yukon, Height of 147

— on the upper Yukon, Mention of "•. 122

r»-i is-too Included under the name Yukon 106, i|is

— . Measurements of 106, |"~

TiMi.n: linp on monnt • 'tie International boundary

in Taiya valley, Height of 151

Topoqbafhy of Unalaska i&land > ■ ' ;"

rum) of fault scarp near the International boundary

I I MDB* <-'"

— . Character and origin of lake- on 128

— , I .li oi the increase of depth of 187

— , General ol of 125 126

— , Mode of formation of 126-127

— on the delta of the Yukon m

— , Possible explanation of the origin of coal furnished l>y 121

— , Stratified ice in 128 129

— , The name derived from Siberia 126

kbb, J. H., Courtesy of 108

— , i of the Porcupine river

— , In charge "f boundary Burvey l"i

TniM p:, L. M., Cited "ii the origin of clear ice in the tundra l 28

— , Reference t" description of the tundra by

is. e of decayed rocks on I i

— , \ f evidence of general glaciation mi 138-138

— , Arrival at 1"!

— , (Character "f vegetation on 126 126

— , Topography of 188-140

V m i bts formed by the erosion of jointed rocks 100

\ "oi.i lkic dusl in stream terraces 146-146

Wiim Hobsi rapids, Read of navigation at 126

Whits p > survey of 103

Win i ■ river, Character of the water of 116

u/oodh Mill, R 8., I »i-'-ii — i'-ii ol heal diffusion by 180-132

\Viii..iir, <;. I'., Cited on glaciers In southern Alaska i ■-

Y.iki i-h, 8iberia, Depth of frost :it 130

•• y. .rt of, from St Miohw Is 101

— , Voyage of, on the Yuk ind Porcupine rivers i-i

Vims deltH, Description of 110 112

, Suggested survey of

— , Lake, Description of 146-1 1-

— river ilong 1.1

, A' IsJ records along 140 111

, Beginning of Journey on 101

— 117

, Character 1 116-116

[doting and opening oi 116-117

, Deposition of M I laj In * 120

1 oi band ol . 11

, Drift-* ii" 111

, 1 logyol 110

, Glaclati 11 "i mof 141-144

In vrlntei 116 117

. Mammoth remains In

, M . I ment in 111.

1 Mil. id it trlbuiai 11 116

— 124

1 Nomenolal f 104

1 intaii

,ii . iso

— 117 184

, Spring freshets in 117

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA

VOL. 1, PP. 163-174; 175-194

NOTE ON THE PRE-PALEOZOIC SURFACE OF THE ARCHEAN

TERRANES OF CANADA "

THE INTERNAL RELATIONS AND TAXONOMY OF THE
ARCHEAN OF CENTRAL CANADA

AN DEE W C. LAWSON

WASHINGTON

PUBLISHED BY THE SOCIETY

March, 1890

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA
Vol. 1, pp. 163-174 March 12, 1890

NOTE ON THE PRE-PALEOZOIC SURFACE OF THE ARCHEAN

TERRANES OF CANADA.

BY ANDREW C. LAWSON, PH. D.

[Read before the Society December 27, 1889.)

CONTENTS.

Page

Introductory Eemarks 103

The Phenomena in Central Canada 164

Contacts between the Animikie and the Archean 1G4

Contacts between the Nipigon and Older Rocks 166

The Phenomena in Eastern Canada 167

Contacts between the Paleozoic and the Archean.... 167

Review of the Evidence 169

General Considerations 169

Former Extension of the Paleozoic 169

Transgressions and Oscillations in Level .— 171

The Erosion of the Archean 172

Source of Paleozoic Sediments 172

Discussion 173

Introductory Remarks.

Since the establishment of the glacial theory the cause of the hummocky
and roches moutonnees character of the rocky surface of the Archean terranes
of North America has generally been ascribed to the action of the ice of the
glacial epoch. Two opinions have been prevalent, having this belief as their
basis. The first and older view was, in accordance with the theories pro-
mulgated by the Scotch geologists, that the hummocks and their complemen-
tary hollows were produced by the direct plowing or gouging action of glacier
ice loaded with rock debris. The second and more modern view is, that just
as south of the terminal moraine we find the crystalline rocks extensively
decomposed in situ, so prior to the advent of the glacial epoch the Archean
terranes of the north were similarly decomposed, and the present hummocky

XXII— Bull. Geol. Soc. Am., Vol. 1, 1889. (163)

164 \. (. LAWSON — Till PRE-PALEOZOIC SURFACE.

Burface r< presents the locus to which rock decay had extended in depth. In
this view the ice .-imply removed the rotten rock, Bcouring ami polishing
tin fresh Burface upon which it rested, and the hummocky character is due
rather to the principles which govern the decay of rocks than to ice action,
which is only held responsible for laying the surface bare. All students of
glacial geology will concede that in both of these opinions there Is a certain
amount of truth, though much more in the Becond than in the fust.

rvations, however, which the writer has been enabled to make
at odd times during the past few years, indicate that these hypotheses do not
afford u- the correct explanation of the hummocky aspect of the Archean
Burface, bul that the latter, in it- essentia] ami prominent features, long
antedates the glacial epoch, and was as characteristic of the surface upon
which the earliest Paleozoic sediments were deposited a.- of that upon which
the greal Canadian glacier rested in glacial times. These observations have
been made along the northern limit of the undisturbed Animikie and Nipigon
strata, where they resl direct ly upon the Archean surface, on the north shore

I Superior, between < runflint lake <>n the international boundary and
the meridian of the Slate islands. The conclusions which they forced upon
the writer have been confirmed by an inquiry which he has made into the
condition- which prevail along the line of contact of the undisturbed Paleozoic
rock- u] the Archean in more eastern portion- of Canada.

In a paper of the present compass it will scarcely he possible to do more
than indicate the localities where the evidence may be found, and to sketch
tin' latter at each place in -cant outlines.

IH i I'll i \< >mi:n a -u Central Canada.

I darts between tin Animikii >ni<l the Archean.— On the north side of
Gunflinl lake the superposition of the northern edge of the Animikie upon
the Archean is well seen. To the north of the edge of the Animikie for-
mation- the Archean rises in low hummocky hills, the ridges of which, when
these are present, coincide with the strike of the rock-. This hummocky

surface may be walked over close up to the A nimikie. and it may be Been to
form an undulating surface upon which the latter rests. At the west end of
the lake, on the north Bide of Black-fly bay, on mining locations R. 315 and
l; 317, i- an outlier of the basal beds of the Animikie resting on a ridge of

I urentiai -, with hollow.- sither Bide of it, and tin' Animikie al

the bottom of that on the BOUth, the whole Bhowing very clearly that the

present shape of the surface of the Laurentian was practically that upon

which the Animikie was laid down. The direct repose of the tlat

A nimikie upon t he upturnei of the Keewatin schists Is also observable

a mile and three-quarters from the east end of the lake, and here the Burface

HUMMOCK Y ARCHEAX SURFACES. 165

is of the same uneven character as that of the uncovered, glaciated country
to the north. Similar contacts may be seen inland a short distance, near
the head of the lake ; and on Gunflint river the Laurentian gneiss, in low
roches moutotmees, appears partially encircled by the Animikie rocks.

On the north side of North lake there flows in a creek at the bottom of a
deep gorge, which cats down through 200 feet of flat Animikie strata to the
basement of Laurentian gneiss upon "which they rest; and the basement is
distinctly roches moutonnees. Similar conditions are observable two miles
up the creek which flows into the east end of North lake, and on Sand lake,
where escarpments of Animikie strata overlook and appear to overlie a hum-
mocky surface of Laurentian gneiss. The same is true of the escarpments in
the vicinity of Little Gull lake.

To the north and northeast of Little Gull lake is a group of five small
steep-sided, flat-topped hills, known as the Outpost hills, which are outliers
of the Animikie, capped as usual with a sheet of columnar trap. The dis-
tance which separates them from the main area of these rocks varies from
one to four miles. This space is occupied by a very hummocky and roches
moutonnees stretch of Laurentian gneiss which maintains the general level
of a line extending from the base of the Animikie on the face of the escarp-
ment to the base of the same series, where it rests on the Laurentian at the
foot of the Outpost hills. The writer has been over the ground between the
escarpment and the hills; and Mr. E. D. Ingall, of the Geological Survey
of Canada, who has examined the hills carefully, informs the writer that
the actual base of the Animikie may be distinctly observed resting upon
the uneven, hummocky Laurentian surface, the sections being perfectly ex-
posed.

Less than half a mile above Kakabeka falls small outlying patches of the
basal beds of the Animikie may be seen lying in the hollows of the mam-
millated surface of the Laurentian, and the latter, as it rises from beneath
the Animikie, above the falls, is exceedingly hummocky.

Along the Dawson road, a few miles back of Port Arthur, low, rounded
domes of Laurentian gneiss appear in the midst of the Animikie, projecting
above the level of the local upper beds.

On Current river the Laurentian rises in hummocky hills from beneath the
Animikie slates and traps, although the actual contact has not been observed.
Between this and McLean's siding, seven miles east of Port Arthur on the
Canadian Pacific railway, the Archean rises in the same hummocky hills
from beneath the Animikie, the line of contact being concealed by a narrow
strip of swamp. At the siding the contact is only concealed by the width
of the road-bed, and the surface of the Laurentian gneiss is seen to plunge
down under the flat Animikie rocks with the slope of a steep dome, appear-
ing again in a less prominent but still hummocky outcrop close to the con-

L66 A. (. LAWSON — THE PRE-PALEOZOK SURFACE.

tad of the Animikie, on the wagon trail about midway between (Jreen point
and Wild < roose point.

At Silver barbor, farther up the north side of Thunder bay, there ia a strip
of the Animikie consisting of 1"» to 20 feel of flat Blates and cherty beds,
capped by 50 feet of trap, from beneath which on the north, acrossa narrow
Btrip of swamp, rises the Archean surface in well-defined rochea moutonnet t.

Contacts hetween the Nipigon and Older Rocks. — In the vicinity of Loon
lake the basal beds of the Nipigon series overlap the northern edge of the
Animikie and rest in undisturbed attitudes directly upon the Laurentian.
On the north side of Loon lake and eastward to the vicinity of Pearl river
the Laurentian rises from beneath the Nipigon sandstones and conglomerates
in prominent hummocky hills. These conglomerates are made up very
largely of boulders and rounded pebbles of the Laurentian, which are in-
distinguishable in general aspect from the more rounded erratics in the
glacial drift.

In the bed of the creek at the tank of Pearl river station a low, rounded
hummock of Laurentian gneiss appears from beneath the Nipigon sandstom
and at the first rock cut east of the station, 200 or 300 yards distant, the
Bandstones may he seen in the vertical section of the cutting, resting upon
the -lope of a hummock of Archean schists and dipping away from it to the
eas! at an angle of 15°. Here the Bchists are rotted in places, leaving a few
harder nuclei or boulders of disintegration in situ. Haifa mile farther
east along the track prominent, lumpy knobs of Laurentian rise above the
level of the Nipigon Bandstones to a height of over 100 feet, and on the east
side of these, in a rock cut of the railway, the -andstones may he seen repos-
ing directly upon their slopes, a- an outlying patch.

About ten miles east of Nipigon, on the ( !anadian Pacific railway,there i- a
prominenl bluff of Nipigon sandstone, capped with a thick sheet of verti-
cally columnar trap, the whole presenting escarped faces which rise mi three
sides precipitously for several hundred feel above the hummocky plain of
Laurentian rocks upon which it rests. The bare Laurentian basement is
traceable up to the talus at the bases of the cliffs, and presents the appear-
and t passing under the column of superincumbent strata in the same

hummocky condition as that which it has beyond the dill'-.

Aboul ten miles east of Mazokama station on the Canadian Pacific rail-
way ;t prominent point runs out into the lake, the core of which consists of
hummocky Laurentian gneiss, and the outer margin or shore of superim-
posed Nipigon Bandstones and conglomerates. Here again the Laurentian
appear- to pass under the Nipigon with its characteristically hummocky sur-
face, the country being well bared ; and thai it does bo is proved beyond
question by the fact thai scattered over the Laurentian ana, away from the
edge of the Nipigon rocks, there are numerous outlying patches of the basal

ARCHEAN SURFACE UNCHANGED SINCE THE NIl'IGON. 167

beds of the Nipigon resting in situ in the hollows between the Laurentian
hummocks, both at the bottoms of the hollows and on the steep slopes.
These patches are usually not more than a few chains in diameter ; and their
relation to the Laurentian affords incontestable proof that the surface of
the latter has undergone uo material change since they were deposited upon
it. At Rossport the Animikie rocks come in again between the Archean
and the Nipigon, and here also may be seen, near the railway station, in a
hollow between the Laurentian hillocks, an outlying patch of the basal beds
of these rocks.

Along the shore of the lake between Rossport and Black river, north of
the Slate islands, there are occasional patches of the Nipigon amygdaloidal
traps which have escaped removal by erosive agencies, and these all repose
upon a hummocky Archean surface. In none of these instances is there
any evidence of a perceptible reduction of the mean level of the glaciated
surface of the Archean below that upon which the Nipigon or Animikie
rocks rest. A noteworthy fact also is, that with one exception none of the
Archean rocks, where they pass immediately beneath the Animikie or Nipi-
gon, show the slightest evidence of decay. On the contrary, they are
remarkably fresh and free from even the incipient decomposition of weather-
ing. The exception is the case of the schists in the rock cut east of Pearl
river mentioned above. All the Laurentian gneisses and granites are per-
fectly fresh in their macroscopic aspects. Another interesting point, which
will be alluded to again, is the transgression northward of the newer Nipigon
rocks beyond the edge of the older Animikie.

The Phenomena in Eastern Canada.

On instituting a comparative inquiry into the conditions which obtain
along the escarped line of the abutment of the undisturbed Paleozoic upon
the Archean in eastern Canada, it is found that the evidence here confirms
the conclusions arrived at on Lake Superior as to the general character of
the pre-Paleozoic Archean surface.

Contacts between the Paleozoic and the Archean. — Laflamme in his " report of
geological observations in the Saguenay region"* seems to have arrived at
much the same conclusion as the writer. After describing a new area of
the Trenton rocks in the vicinity of the Saguenay " which rest directly on the
gneiss," and stating that "their thickness is so slight, at least on the border
of the formation, that the undulations of the gneiss are brought to light
through their edge," he gives an account of various outliers and says by way
of summary : " I have pointed out in the course of these remarks the fact
that limestones (Trenton) are often found iu nests or outliers amongst the

*Geol. Survey of Canada, Report Progress for 1882-3-4, Part D.

L68 A. C. LAWSON — THE PRE-PALEOZOIC SURFACE.

granites. Therefore, these depressions and hills of Laurentian must neces-
sarily have existed at the bottom of the Paleozoic ocean when the limestone
beds were being deposited.'9

Mr. A. J'. Low, of the Geological Survey of Canada, who has been more
recently engaged in tracing out the northern limits of the Paleozoic on the
north side of the St. Lawrence, west of Quebec city, informs the writer that
at several places he has noted the superposition of the Trenton or Lorraine
beds directly upon the hummocky Laurentian surface, and that there has
been no reduction of the surface where it projects from beneath the escarp-
ments, below that where the flat strata rest upon it. He notes the following
localities as affording particularly good sections : — Between Lorette village
and St. Ambrose railway station, Q. L.St. J. railway; west of Belair station,
C. P. railway: Ponl Rouge station, C. P. railway (section on Jacques Cartier
river); Deschambault, near railway station. Air. Low also informs the
writer that the undisturbed limestones of Lake Mistassini, in southern Lab-
rador, may be observed to rest upon hummocky Laurentian surfaces ; and
that on the Bast-main coast of Hudson's hay similar flat lying strata may
lie seen in the transverse section afforded by Richmond gulf, resting on a
very hummocky surface.

In eastern < mtario, the best evidence we have hearing on this question is
contained on Air. E. ( 'oste's "Geological and Topographical Map of the
Madoc and Marmora Mining District." recently published by the Geological
Survey of Canada. N<> report accompanies the map as yet, hut the writer
has had the benefit of frequent conversations with Messrs. Coste, Ami, and

White, who were employed in the field-work necessary for its < struction.

Prom the map and from the information thus supplied, it is clear that in the
area mapped we have a remarkably striking illustration of the superposition
of flat, undisturbed Paleozoic strata (Birdseye and Black Liver) upon a
very hummocky and mamniui I lated Archean .-urface. The northern border
of the Paleozoic is lure very irregular in outline, and beyond the limit of
the main area there are very numerous outlier- scattered over the country.
Both along the edge of the escarpment and at the periphery of many of
tin- outlier.-, the flat strata may he seen resting directly on the rounded
hummocks; and these, out beyond the escarpment, often risehigh above the
lower horizontal strata. Many of the outliers, also, are mere patches resting
in aitu upon the Bteep Blopes of these hummocks. Many are bul a few
chains in diameter, and others only a few yards. Further, there may be
repeatedly Been projecting through the upper surface of the Birdseye and
Black River formations rounded knobs of the Archean, in the shape of in-
liers well within the Paleozoic area. These are clearlj the crests of partially

■ it., p, is.

TIIK FOUNDATION FOR THE PALEOZOIC. L69

uncovered hummocks ; and the phenomenon is so common as to leave no
doubt as to the character of the underlying surface.

Review of the Evidence.

Thus, wherever careful observations have been made as to the nature of
the superposition of the undisturbed Paleozoic rocks upon the Archean,
whether in the Lake Superior country, eastern Ontario, Quebec, or Labrador,
the evidence points to the same conclusion, i. e., that the early Paleozoic rocks
were laid down upon a surface which did not differ essentially from that pre-
sented by the exposed Archean surface of the present day upon which the
great Canadian glacier rested ; and that there is no good evidence of that
surface having undergone any material reduction in level, in consequence
of the conditions of the glacial epoch, either by any plowing power some-
times ascribed to glacier ice, or by the removal of the products of extensive
rock decay.

General Considerations.

In the foregoing pages the evidence, although briefly sketched, has been
specific, and attention has been confined to the immediate vicinity of the
edge of the Paleozoic formations. Let us turn now to a somewhat broader
aspect of the question.

Former Extension of the Paleozoic. — There is excellent presumptive evidence
that the greater part, if not the whole, of the Canadian Archean terranes
were at onetime covered by Paleozoic strata, and the assumption so generally
made that they have always formed an upland region, serving as a source of
supply for the sediments which built up the Paleozoic formations, appears to
be scarcely warranted by the facts.

The reconnaissance work of the Geological Survey of Canada, while it has
only effected an examination of a number of linear sections across the arms
of the V-shaped Archean nucleus, along the various canoe routes which
traverse it from the waters of the St. Lawrence and Lake Winnipeg systems
to the waters of Hudson's bay, has yet established the fact that there are
basins and outliers of Paleozoic rocks scattered over its surface which appear
to be but the remnants of once far wider spread formations. In the region
of the Saguenay, Laflamme * has described various outliers of Trenton other
than the well known one at Lake St. John, and the distribution of these
shows clearly that this formation must have extended for at least 150 miles
north of the St. Lawrence, over what is now for the most part bare Archean
surface, and the probability is that it extended much farther.

: Op. cit., pp. 10-15.

170 A. '. LAWSON — Till PRE-PALEOZOK SURFACE.

To the north the explorations of McOual ami Low have established the
existence of another large and important outlier of undisturbed Paleozoic

rocks over inn miles in extent, about 150 miles bey 1 Lake St. John, at

Lake Mistassini. These rocks arc chiefly limestone in which as vet no

lis have been found, and which an' referred provisionally to the ( lambrian

from certain resemblances to the Hat Btrata of the east coast of Hudson's

hay which are BUpposed to he of that age. These latter rocks occur along
the Bast-main coast, resting in undisturbed attitudes upon tin- Archean.
Inlaml from this coast, al-o. Mr. Low found in the drift which come- from
the east, "l- the interior of Labrador, a limestone boulder containing Silurian

-ils. which indicates the presence of an outlying area of such rocks in that
region.

On the upper Ottawa, in the vicinity of Pembroke, we find extensive
Canihro-Silurian outlier- as much a- 50 miles from the edge of the present
main Paleozoic basin. Other outliers are also found on the islands of Lake
Nipissing, ami on Lake Temiscaming nearly ion miles north of Lake
Nipissing. There is thus Lr<>"d reason for supposing that the Paleozoic sea-
extended tar over the whole of the upper Ottawa country.

The great Siluro-Devonian basin of the west side of James's hay extends
southward to within Inn miles of the north shore of Lake Superior, and
farther wot the rucks of the Nipigon basin extend northward for 100 miles.
The former extends south and the latter north of the 50th parallel of latitude,
and the east and west distance between the two basins along the parallel is
only about inn miles. It is entirely probable that both of these basins only
represent what is left by erosion of a much more extensive distribution of
the respective formations constituting them ; and that they do not in reality
correspond in area to the original basins of deposition, hut are rather basins
of shelter from erosion, such as all the Paleozoic outlier.- appear to he.

( )n tie- southwest -ide of Hudson's hay there is another extensive area of
Silurian rocks, traversed by the lower stretches of the Churchill, the Nelson,
the Have-, and the Severn rivers. These rocks resemble those of the same
in the basin of the Red river and Lake Winnipeg, both as regards their
t "• • — 1 1 remains and their lithological characters. The Hudson's bay area of
these ruck- i- separated from that on Lake Winnipeg by about -"" mile of
Archean country, with no prominent elevations betwei a, and it i- therefore
quite probable that they were once connected, and that the formations of
which they are constituted extended continuously across this northwestern
arm of the V-shaped Archean "nucleus." An outlying ana of sand-
stones of unknown age also rests upon the Archean at the east end of
Athabasca lal

Thus, considering the very limited extent to which this Archean "nucleus"

. Vol. Mi

FORMEB EXTENSION OF THE PALEOZOIC. 171

has been explored, the indications that it was once very extensively if not
wholly covered by formations of Paleozoic age are both numerous and im-
portant. The lines of examination have been chiefly confined to the
ordinary routes of travel followed by the fur traders, and these are not
numerous. "When the country comes to be more closely explored there is
every reason to suppose that many other outliers, such as those of lakes St.
John, Mistassini, Nipissing, and Temiscaming and the Ottawa river, will be
found scattered over its surface, and that the evidence of the once wide-spread
distribution of the Paleozoic formations will accumulate.

Transgressions and Oscillations in Level. — But here a word of caution and
modification is necessary. While the evidence indicates that a covering of
Paleozoic (Cambrian to Devonian) once spread over the Archean surface, it
does not indicate that the rocks of the lower horizons were thus widely
spread. On the contrary, it is to be noted that thei*e are distinct evidences
of the transgression of the formations of higher horizons over the limiting-
edges of the lower. Thus, on Lake Superior, the Nipigon rocks may be dis-
tinctly observed to overlap the northern edge of the Animikie formation and
extend northward far beyond it. In the St. Lawrence and lower Ottawa
region, rocks of Potsdam and Calciferous age are abundant. Further
north these are absent, and in the upper Ottawa outliers the Chazy rests
directly upon the gneiss. In the vicinity of Madoc this also is lacking, and
the Birdseye and Black River beds rest directly upon the gneiss. This
appears to be true also of the outliers on Lake Nipissing. Thus, in ascend-
ing the Ottawa, the Chazy overlaps or transgresses both Potsdam and Calcif-
erous, while at Madoc and Nipissing all of these are transgressed by the
Birdseye and Black River. This, in turn, and all older formations, were
trausgressed by the Niagara, as is indicated by beds of that age resting
directly on the Archean on Lake Temiscamany.

In the Province of Quebec the same condition of affairs is found.
In the vicinity of the St. Lawrence, the Chazy and Calciferous rocks
abound. To the north of this, in the Saguenay country, Laflamme remarks
as a noteworthy fact, that in all the points of contact which he has been
able, to observe between the Laurentian and the Trenton, the latter rests
directly upon the former, no traces of Potsdam, Calciferous, or Chazy being
seen. Moreover, whilst the Utica formation is present only in a few instances,
still debris from it are found on the shores of the lake (St. John), and very
often inland to such au extent that we are forced to conclude that the whole
area of the Trenton was formerly covered with this formation.

Thus, while the evidence indicates that the Archean "nucleus" was once
covered very extensively by Paleozoic formations of one horizon or another,
it appears probable that it was not extensively submerged till the time of
the Trenton, and that it was much more extensively submerged during the

XXTII— Bull. Geoi,. Sue. Am., Vol. t, 1880.

1/2 A. C. LAWSON — I'll I. PRE-PALEOZOIC SI RFAC1

deposition of the Niagara than in earlier epochs. It would follow from
these considerations, that as Paleozoic time advanced from Cambrian to late
Silurian or Devonian there was a gradual and progressive subsidence of this
portion of the continent. A- we have no evidence of the deposition of post-
Devonian formations anywhere over the Archean "nucleus" till we come
down to post-Tertiary, it may In- tentatively inferred that after the Devonian
it was again elevated, and this elevation probably only reached its maximum
during the glacial epoch, affording the conditions of altitude contended for
by many writers to explain the great precipitation of -now. In post-glacial
times we kmiu from the distribution of such formations a- the Leda clay
and Saxicava -ami that the northern part of the continent was again par-
tially submerged for several hundred feet, from which depression it has since
recovered : we thus have evidence of a slow ve tical pulsation of the surface
of this part of the continent, of which there have been at least four great
beats since early Cambrian time.-.

But this is a digression, and the argument which has led to these remarks
wa- inaugurated to .-how simply that the surface of the Archean •• nucleus "
wa- once very extensively if not wholly covered by Paleozoic sediments.
This covering probably accounts in a large measure for the remarkable
preservation of the Archean surface in the condition in which pre-Paleozoic
denudation left it. There are other considerations which help us to under-
stand tin.- preservation, such as the levelness of the plateau and its corapari-
tively low altitude, combined with the very resistant character of most of
it- rocks, which appeal- to lie little susceptible to that erosive or corrasive
action of streams which i- so effective in removing the more yielding Btrata
of post-Archean age. The-, considerations will not, however, he em, Ted
upon hi

'I'ln I m "(Hi' Archean. — One i- constantly impressed by the perfectly
appalling amounl of denudation t<> which the Archean has been subjected in
order to truncate its formation- down to the surface which it presents to-day.
A ml w hen «re reflect, as a result of the conclusions here arrived at. that this
denudation was practically completed before the beginning of earliest
Paleozoic time-, ami has not been, a.- commonly supposed, the result of later
there looms up a conception of the pre-Paleozoic interval necessary
for Buch denudation which stag ten the most Btalwart geological

imagination. T" saj that i; must have been comparable with all the time
which ha- succeeded from the earliest Cambrian to the presenl seems but a
feeble way of exp it.

P Sediments. — The c iption of a covering of Paleozoic

strata over the gurfai I the Archean " nucleus," which probably endured

into comparatively recent geological times, enables us to a larg< extent to
understand i I rvatiou of the pre-Paleozoic Burface, hut it also raises the

SOURCE OF PALEOZOIC SEDIMENTS. 1 i :>>

important question of the source of the sediments composing those strata.
If such a wide-spread formation as the rocks of Niagara age was deposited
over the surface of the Archean " nucleus," as well as over the regions which
encircle it, it is clear that the Archean " nucleus " could not have been the
source of supply of those sediments. Some other portion of the continent,
or some other region now submerged, must have constituted the dry land of
that time. Where that region lies is a question yet to be answered.

DISCUSSION.

Professor J. W. Spencer: The facts set forth in this very interesting
paper by Dr. Lawson have their counterparts in the geological structure of
the South. The hummocky and rounded rock surfaces have always had an
interest for me, on account of their common occurrence in regions which
have been glaciated, and hence regarded by many as evidence of glacial
erosion. But in the paper of Dr. Lawson we learn that such surfaces existed
before the formation of the early Paleozoic terranes. Some of you may be
familiar with Stone Mountain, about fifteen miles from Atlanta, Georgia.
This is a rounded granite hummock of over a mile, in longer diameter, rising
700 feet above the plain. The rock is remarkably free from joints, and is
rarely traversed by even an insignificant vein. Thus its structure has been
favorable to the preservation of the rounded form, whose outline is as perfect
as any of the domes of glaciated Norway or Canada ; or of southeastern
Missouri, which lies outside of former glacial action. Stone Mountain rises
from beneath very much disturbed strata of gneiss, whose beds dip to the
southeast, and there is no gradation of any importance between the granite
and the gneiss. The gneiss is decayed to a depth, in some places, of at least
sixty feet ; but the granite is compact, without being weakened by even
incipient decay. The surface materials, as fast as decomposed, are washed
off by the rains. Thus the contrast between the two formations of rocks is
preserved. This Stone Mountain is only one of many in Georgia and Ala-
bama. Here, then, we have, in the South, pre-Paleozoic surfaces as old as
or older than those described by Dr. Lawson in the Lake Superior region,
and brought to light by simple atmospheric action. Along the Potomac
river we find hummocks being formed by the progress of atmospheric in-
vasion along lines of joints, but these are now in process of formation, and
do not represent so ancient surfaces as those of the granite hummocks of
the South.

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA
Vol. 1, pp. 175-194 March 20, 1890

THE INTERNAL RELATIONS AND TAXONOMY OF THE
ARCHEAN OF CENTRAL CANADA.

BY ANDREW C. LAWSON, PH. D.

(Ri'Uil before tJte Society December 28, 1889.)

CONTENTS.

Page.

Primary Separation of the Archean into two Divisions 175

The Upper Division 176

Nomenclature 176

Petrographical Description 177

Original Characters and Metamorphism 180

delations between the two Divisions 181

The General Relations 181

Irruptive Contact on Lake of the Woods 182

Irruptive Contact in Rainy Lake Region 183

Significance of Relationship 185

Principles of Classification ... 186

Principles applicable to the Upper Division 186

Principles applicable to the Lower Division 18G

Different Generations of Laurentian Rocks 187

Other Conditions considered 187

Similar Observations elsewhere 188

Geognostical Equivalents of the Archean 190

The Argument from Analogy 193

Primary Separation of the Archean into two Divisions.

Throughout North America, geologists have long recognized in the great
fundamental complex of rocks, known generally to-day as the Archean, a
natural division into two well-characterized portions, related to each other
in space as upper and lower. The lower division is commonly known as
the Laurentian, and consists for the most part of an assemblage of rocks of
the character of granites, syenites, diorites, and gabbros in mineralogical
composition, but more or less foliated or gneissic. Involved with these in a
way not hitherto understood there are also, in sorr? regions, portions of

(175)

170 A. < . LAWSON — RELATK >NS OF THE A In II IAN OF CAN \ l>\.

various gneiss, Bchist, limestone, quartzite, :in<l conglomerate formations,
which, not being easily separable from the foliated granite rocks, have been
sometimes classed with the latter as Laurentian.

The Uppee Division.

lenclature. — The upper division is of very varied lithological character,
and various oames have been applied to it, or to portions of it, in different
regions. Until recently it has been customary to apply the term Huronian
tn a part of this upper division on account of its supposed equivalence to the

ies of locks so named by Logan and Hunt in L855.* But if the original
conceptions of these eminent geologists and t he more recent contentions of
Irving, corroborated by Professors X. EL Winchell and A.. Winchell, are
<onvct — viz., that the Huronian and Animikie are geologically equivalent, —
then we cannot in reason perpetuate the incongruity of applying the same
name to two groups of rocks which lie one ou either side of probably the

atesl hiatus in American geological history. The term Huronian must
be retained for the -roup of rock- on Lake Huron first SO named and its
equivalents; ami. in view of the evidence which has been adduced of the
unconformable superposition of that group upon the Archean and it- prob-
able equivalence with the Animikie, which rests upon the Archean in glaring
unconformity, it seems inappropriate at present to apply the term Huronian
to any portion of the Archean. We are thus, at the outset of any inquiry
into the Archean, hampered by the lack of an acceptable designation for
the great system of rock- which constitutes ii> upper division. Even if the
Huronian group be demonstrated to lie upon the remote side of the great
post-Archean hiatus, it would then be only one of several groups thai go to
form the system which constitutes the upper division of the Archean com-
plex, ami the system itself would .-till he nameless. Ai least one other great

up of locks — the < ' lutchiching i possibly the equivalent of the Montalban
of Hitchcock I — baa been brought to light, which is not second in taxonomic
importance to the various belts of rock- Bimilar to the Keewatin, which have
been correlated with the Huronian. 80, granting that the Huronian shall

one day hold an unchallenged position in Archean taxonomy, il will not
have a higher rank than that of a group."]

1 'i am the Geological Mad and the ( olleciion "i
lomic M ■ . nihil Ion at P E, Logan a ■ rry

Ibition ol in 1 lo- sketch, in which the

term Hu iwn an the Anl iken

■ Huron, and the whole is the " Huronian or

1 unconformably upon I he I iaui

to them by the
I'm v, in tin' tcheme published in I i Annual !•'•■■

■1 1 in \ re I lean com pie \. The
herwlse 1 « ith any n"1"'! i

THE ONTARIAN SYSTEM PROPOSED. 1m

Having these considerations in mind, it seems desirable, in the cause of the
concise expression of our knowledge and of the furtherance of clear and
simple conceptions of Archean geology, that the taxonomic value of this
upper division of the Archean should be recognized by the adoption of an
appropriate designation of systemic import. There is probably no other
equal area of the earth's surface Avhere the formations of this system are
better or more extensively exposed than in the Canadian province of Ontario.
The writer therefore begs to suggest to his fellow-workers in American
Archean geology that this system be known as the Ontarian System.

Petro graphical Description. — The formations of different groups of the
Ontarian system present for the most part a sharp contrast in lithological
character and mode of occurrence to those of the Laurentian system. The
latter, as has been indicated, consists essentially of an assemblage of more
or less foliated or quite massive varieties of rocks which are to-day recognized
by petrographers as plutouic igneous rocks — e.g., granites, syenites, diorites^
gabbros, etc. The former is composed of rocks which are with varying
degrees of certainty recognized as normal sedimentary and volcanic forma-
tions disguised by metamorphism of different kinds. Among the more easily
recognizable formations may be mentioned conglomerates, grits, quartzites,
graywackes, clay slates and limestones; various pyroclastic rocks, such as
ashes, tuffs and agglomerates; and massive volcanic rocks, both acid and
basic, notably quartz-porphyries and diabases ; all of which rocks, far from
beiug peculiar to the Archean, are normal constituents of Paleozoic and
later geological systems. In all of these, schistosity may be a feature of the
rock.

With these normal or only slightly altered rocks occur also more highly
altered facies of the same formations, whose derivation is known, and others
still more differentiated from unaltered types, whose historical derivation
from normal rocks cannot be traced with certainty, but only inferred by
analogy as highly probable. Of those rocks whose original character is
more or less obscured, the most prominent are certain phyllites, mica schists
and feldspathic mica schists or gneisses, so called ; hornblende schists and
amphibolites, serpentines, soft, dark, glossy, green schists, and various light-
colored acid porphyroid schists, nacreous sericitic schists and felsitic schists
with quartz grains. These are all rocks upon which there has, in recent
years, been concentrated a great amount of research both in the field and in the
laboratory, aud many facts have been established concerning them in various
pares of the world which enable us to formulate definite and well-grounded
conceptions as to their origin and development, where formerly only more
or less indefinite speculation was possible.

The rocks known as phyllites or phyllitic schists are very common in fos-
siliferous series in disturbed regions, and their clastic origin is -rarely ques-

L78 \. i . i w\ son — i;i:i. itioxs of the lrcheax of caxada.

tioned. In the A.rchean, rocks of this and more pronounced micaceous
character to true mica schists are traceable into clay slates and Biliceous
clastic rocks with unobscured original characters. Other mica schists arc
dircctlv traceable into conglomerates and agglomerates, and appear to be
but excessively squeezed facies of these rocks where the conglomeratic or
agglomeratic characters have been obliterated and much mica developed.
Ami in -nine mica schists, where no direct transition can be established, tra<
of conglomeratic structure can occasionally be detected. The mosl distinct ly
crystalline of these mica schists are entirely comparable with the mica schists
of the Bergen peninsula in Norway, where Reusch a few year- ago found
beautiful Silurian fossils,* some of which the writer has himself more recently
collected under the guidance of that distinguished geologist.

Many mica Bchists of the Ontarian system arc, further, entirely similar to
the " hornfels " or crystalline schists of the contact zones of various post-
Ajrchean granitic irruptions, which are undoubtedly the altered facies of
normal sediments. Some of the feldspathic mica schists, of a fine-grained,

thinly laminated aspect, < imonly called gneisses, are in parts of the

Ontarian system traceable into quartz-porphyries of the same normal

character a> those which constitute the vulcanic portions of many Paleozoic
-eric.-. The researches of Lehmann f have established Buch transformations
as tacts, the explanation of which, as demonstrated by thai eminent investi-
gator and now generally accepted, is found in the deformation of the rock by
pressure and in the chemical activity induced thereby. For the mosl part,
however, the feldspathic mica schists, such as are abundant in the Coutchich-
ing group, are, like the non-feldspathic mica Bchists associated with them,
very probably of metamorphic derivation from normal Bediments.

In port inns of these format ion- the writer has recently detected vestiges of
conglomeratic structure. In places they pass into rocks that are little more
than slightly micaceous quartzites, and their distinct bedding and regular
stratigraphy are those of sedimentary rock- as contrasted with the lenticular
arrangements which obtain in volcanic accumulations. Their contact phe-
nomena against the granites and granite-gneisses of the Laurentian are
identical, so tar as Btudied, with intrusive granites, particularly in the

development ofandalusite crystals. They corresp I closely in lithological

character and in the nature of their relation- in the Laurentian with the
descriptions given usby Barrois : of the feldspathic mica schists of Cambrian
. which in Brittany are pierced and altered by great irruptions of granu-
li t > - tin- true granite, or granite with two micas, of the Germans), which
rock forms very extensive portions of the Laurentian northwest of Lake
Superior.

. ii

II, ime :

STRUCTURE ANT) DERIVATION OF THE ROCKS. 170

As to the hornblende schists, the field evidence points to their derivation
from basic volcanic rocks. In places this derivation can be traced step by
step from the massive rock to the schist ; but for the most part no such
transition is observable, and at the base of the Keewatin, in contact
with the Laurentian, there is commonly found a formation of hornblende
schists of whose origin and development we can only judge by comparison
with cases where the history of similar rocks has been thoroughly worked
out and established beyond question. Teall,* in Scotland, and Reusch,f in
Norway, have shown that some typical hornblende schists and more chloritic
hornblende schists may be produced by the shearing of diabase dikes. The
writer has collected specimens of the crushed and scpieezed diabase dikes of
Bommelo described by Reusch, which are indistinguishable from many of
the schists of the Keewatin on the Lake of the Woods and Rainy lake.
Teall's description of the hornblende schists resulting from the shearing of
dikes would also apply to many of the Keewatin schists which occur in bedded
formations. The augite-porphvrites of the Silurian of the southeast coast
of Norway, which have been described by Brogger,^ are, at the contact with
the intrusion of the augite-syenite of Laugesundf jord, where observed by
the writer, altered in places into black glistening hornblende schists, which
are very similar to the hornblende schists of the Keewatin at its contact
with the Laurentian gueisses. Thus, both the conclusions arrived at in the
field and supported by microscopic studies, and the analogies furnished by the
investigations of geologists elsewhere, point to the derivation of the bulk of
the hornblende schists from normal volcanic massive rocks, which were orig-
inally bedded with other stratified rocks, either as flows or as injected sills.
( )ther hornblende schists are probably derived from an analogous alteration
of tuffs of basic volcanic rocks.

The amphibolites are rocks very analogous to the hornblende schists in
mineralogical composition, but massive or non-schistose in structure. They
have probably undergone the same chemical development as the schists,
with pressures so adjusted that no foliation was induced. They are compar-
atively local in their occurrence and do not generally make extensive for-
mations.

The various serpentines, so far as they are known, are for the most part
beyond doubt the alteration products of local bosses of highly magnesian,
massive irruptive rocks. This conclusion is based not simply upon the
investigation of the rocks of this particular field by the writer, but upon
the numerous instances that might be cited from the petrographical writings

* Metamorphosis of DoleriCe into Hornblende-Schist; Quart. Jour. Geol. Soc, Vol. XLI, May,
1885, p. 133.

t Bommeloen og Karmoen med omgivelser geologish beskrevne, 1888, pp. 392-307.

{Spaltenverwerfungenin derGegend Lan^esund: Nyt Magazin for Naturvidenskaberne, XX VIII
Hind, 3die— 4de Hefte, p. 352.

XXIV— Bull. Geol. Soi Am., Vol. 1, 1889

i v" A. C. LAWSON — RELATIONS OF THE A in II i: AN OF I W \I»A.

of net nt years, establishiug such an origin for the hulk of the serpentines
nt present known the world over.

There is :i great variety of fissile, more or lees glossy, rather soft, green
schists, partly hornblendic and partly chloritic, the origin of which in some
cases is closely fixed from the fad that they form the matrix of well char-
acterized pebble and bowlder conglomerates. In this case they must have
been composed of epiclastic or pyroclastic material. The writer inclines t<>
the opinion that they are of proximately pyroclastic origin from the fact
thai precisely similar schists, free of pebbl< -. are frequently associated with
massive or only slightly Bchistose diabas< s, as if the tuffi of these extravasa-
tions. There are many other bedded green schists some of which can he
shown to be squeezed and otherwise altered facies of diabase, while the
precise origin of others is yet quite obscure.

The porphyroid schists, the felsite schists with quartz grains, and many
of the nacreous sericite schists, represent squeezed, schistose and otherwise
altered forms of quartz-porphyries ami petrographically allied rocks, and

their tuffi, winch, as before stated, enter not un< imonly into the composition

of the volcanic portions of normal Paleozoic series. Some others of the
sericitic schists may probably have been developed from sediments rich in
orthoclasc dehris : hut this, except where they pass over into rock- of the
character of phyllites, is not so easily established as the direct derivation of
many of them from the acid volcanic rocks.

Original Characters and Metamorphism.—From the foregoing statement,
brief and incomplete as il is, of the broad lithological characters of the forma-
tion- which constitute theOntarian system, or upper division of the Archean,
it must he apparent that, although there are rucks within it whose hi-tor\ is

more or less obscured by the changes which they have undergone, the system
i- an assemblage of once normal rocks, all of which may he found even in
their in. .-t altered phases in series of Paleozoic and later ages. This conclu-
sion will not appear startlingly new to the very powerful school of American

who have always claimed the met amorphic derivation of the whole

of the Archean from normal rocks.

But, a- will appear in the Bequel, the metamorphic explanation of the
whole of Archean phenomena is not tenable, and is only applicable, in the
opinion of the writer, to \i< upper division, here designated the Ontarian

stem. Moreover, ii is to he noted that the conclusion in question oners an
important modification of the old view of the metamorphic development of
such rocks a- constitute this system, inasmuch a- volcanic formation- have
scarcely been recognized in our leading American text-books as having a

-hare in the composition of the older rock -> ries. Much of the Archean was

properly recognized a- the alteration product- of sediments, and the whole

complex was therefore inferred or supposed to In- of similar derivation from

DISTINCT ORIGIN OF THE TWO DIVISIONS. 181

sediments. It is only in very recent years that the possibility of the deriva-
tion of a portion of the schists of the Archean from volcanic rocks has been
looked into and the important role played by volcauic agencies in building
up the older rock series has been appreciated.* There are, however, not a
few geologists who continue to advocate the extreme plutonic view that the
whole of the Archean is of igneous origin and represents the first-formed
crust of the earth. Hunt's crenitic hypothesis, also, is a challenge to the
metamorphic theory.

In deference to these and other anti-metamorphic schools of thought, in
which for the most part theory seems to crowd out fact, it becomes necessary,
with the accumulation of evidence of recent years, to point out the great
additional strength acquired by the theory of metamorphism as applied to
the Archean, by the recognition of the volcanic origin of much of the material
upon which metamorphic agencies have operated, and by the limitation of
its application to the upper division of the Archean ; the rocks of the lower
division, or Laurentian, being susceptible of an entirely different explanation.
The lack of discrimination between the essentially different characters of the
upper and lower Archean and the lumping of the whole complex together as
haviug necessarily the same origin and development has been the great
mistake alike of the metamorphic and the extreme plutonic schools. Just
as the metamorphic theory, properly limited, affords the explanation of the
development of the rocks of the upper Archean from normal formations, so
by a similar limitation of the plutonic theory and the introduction of some
modifying considerations we will find in the latter a rational and consistent
explanation of the origin of the rocks of the Laurentian.

Relations between the two Divisions.

The General Relations. — The full significance of the sharp separation of
the Ontarian system, as a bedded assemblage of prevailingly schistose and
otherwise altered normal rocks, from the Laurentian, as a non-bedded assem-
blage of more or less foliated plutonic igneous rocks, will appear from an
inquiry into the relations in space and in time between these two great sys-
tems, which it is the object of this paper to institute.

That portion of the Ontarian system which for some years has been some-
what loosely referred to as Huroniau, from its supposed equivalence with the
rocks of Lake Huron, now held to be possibly post-Archean, presents in
many parts of central Canada contacts or lines of junction with the Lau-
rentian. The nature of this contact has been a subject of discussion. The
question has ever been raised whether these rocks are conformable or un-

*The first suggestions of volcanic admixtures in the upper Archean rocks of central Canada were
thrown out by (i. M. Dawson in his description of the agglomerates of the Lake of the Woods in
the Report on the Geology and Resources of the 49th Parallel, 1875, p. 52.

Is'-' L C. LAWSON — RELATIONS 01 I II I IRCHE AN OF CANADA.

conformable upon the Laurentian; the assumption being always that both
assemblages of rocks were composed of metamorphosed sediments. The
answer was held to binge upon the parallelism or absence of parallelism
between the foliation of the Laurentian granites and syenites and the planes
• it' bedding and schistosity of the rock- which are in contact with them. Bell,
Dawson, Selwyn, and McKellar contended for a conformable sequence.
! . gan is silent on this question, hut seems to have been in no doubt as to the
unconformable superp isition of the true Huronian of Lake Huron upon the
Laurentian. limit has always contended for an unconformity, hut as he
also had in mind the true Huronian, which he once regarded as Cambrian,
his contentions do not seem to apply to such rocks as are clearly Archean
and intimately involved with the Laureutian gneisses. It is therefore fair
to say that the drift of opinion in Canada, and probably also in the United
States, is in the direction of conformable sequence throughout the Archean,
without a break between the lower (Laurentian) and upper (Ontarian)
systems. This \ iew has recently been emphatically endorsed by Professor
Alex. Winchell a- a result of his observations in northern Minnesota.
Dawson ha- recently, as a result of his studies of analogous conditions on
the Pacific coast, thrown over his earlier opinion- ;i- to the conformable
lence between these two divisions of the Archean on the Lake of the
Woods, and i- now in accord with the writer as to the natureof the relation-
which obtain there, and which will be set forth in the sequel.f

Irruptivt Contact on Lake of the Woods. — Up to the date of the publication
of the writer's report on the geology of the Lake of the Woods Is"
the possibility of any other relationship between the two greal divisions of

the Archean than those of ( fortuity or unconformity do not seem to have

been entertained. In that report the writer pointed out that the relation-
ship was one of neither i formity nor unconformity, hut id' an entirely dif

ferenl order. Evidence was adduced in some detail to show that the condi-
tions of the eoni act I >et ween the | j\\ w rei 1 1 ja ii a n d t he I\ eew a t i n are essentially
those which obtain between any Paleozoic or later intrusion of granite and
the bedded rocks through which ii breaks. The contact was shown to be
a brecciated one, the granitoid gneiss ramifying through the schists in
apophyses, h >th transverse and parallel to the strike of the schist, and hold-
ing in abundance fragments from tin Keewatin formations, which had clearly

■

been broken off from thi latter while it was in a hard and brittle state and
had found their way into the Laurentian often for considerable distances
from the contact, as well as rn »re n itably in it- proximity. The conditions
observed indicate clearly that we had no question of conformity or uncon-
formity to deal with, hui with ih" contact of an irruptive Lru sous mass, of

pp, 181, 1 lOth An-

il ii ii I

\ '.i it

SUBDIVISIONS OF THE ONTARIAN SYSTEM. L83

later formation than the schists of the Keewatin series, and breaking through
them.

Irruptive Contact in Rainy Lake Region. — The studies here inaugurated
about Lake of the Woods have since been continued iuto the Raiuy lake
region, and still farther eastward to Lake Superior. A portion of the re-
sults are contained in a recently published report of the Geological Survey
of Canada.*

Throughout this region, it was found that the Keewatin is not the only
group in the upper division of the Archean, but that another very volumi-
nous group intervenes between it and the Laurentian, to which the name
Coutchiching has been given.f The relations of the Laurentian to this
group of schists was found to be the same as to the Keewatin, with even
clearer and more abundant evidence of the irruptive and later origin of the
Laurentian. With extended observations it was also noted that the bedded
rocks of the Ontarian system, whether belonging to the Keewatin or Cout-
chiching, present a more highly altered or more crystalline and schistose
facies in proximity to the contact with the Laurentian granite-gneiss than in
the middle portions of the trough, where the rocks are frequently not greatly
altered from the normal character of their analogues in Paleozoic formations.

In other words, there is evidence of contact metamorphism where the
Laurentian rocks come against the shattered and ragged edge of the local
base of the Ontarian system. All the conditions of contact, therefore,
whereby we recognize any mass of granite to be irruptive through stratified
rocks, are found to hold here between the rocks of the Laurentian and On-
tarian systems. The detailed geological mapping of the country shows also
that the Laurentian rocks, while continuous beneath the schist belts, come
to the surface in areas which may be described as isolated bosses. Each of
these is surrounded by a belt of the Ontarian rocks, usually in the form of a
sharply folded trough sunk down into the Laurentian and separating the
surface exposure of the boss from those of its neighbors. These belts of for-
mations of the Ontarian system are, for the most part, compact and cou-

* Annual Report, 1887, Part F.

fit is unfortunate that two new names have become current for this group of rocks. The term
i loutchiching was proposed by the writer in a paper which left his hands in March, 1887, bearing
that date, and which was published in the American Journal of Science in June of the same year.
The geological position, lithological character, known geographical distribution, relations to Kee-
watin and Laurentian, and ihe importance and distinct individuality of this great group, were
stated and discussed in that paper. In the Fifteenth Annual Report of the Geological Survey of
Minnesota, bearing the date of May 1, 1887, but appearing much later, there is a multitude of valu-
able observations and details, but no systematic statement of the geology of the region ; and the
differentiation of the group in question, as geologically separable from the rest of the complex,
does not appear to have been recognized at the time of the writing of the report, although the term
"Vermilion series" occurs once, apparently as an afterthought, inserted on page 299 of Professor
N. H. WinchelPs report. On the maps accompanying the report, however, it is distinguished
clearly by a color and named the " Vermilion series," although here including formations that had
earlier been designated Keewatin. From this it would appear that the term " Coutchiching" was
somewhat prior to "Vermilion," and was more fully and precisely defined as to its geological sig-
nificance. Moreover, the term "Vermilion Lake series" was used earlier by Irving in another
sense than that proposed by Professor N. H. Winchell, and in the same Annual Report (Fifteenth)
the terms "Vermilion series" and "Vermilion system" are used by Professor A. Winchell, on pp.
192, 195, 196, in another and much more comprehensive, but still undefined, sense.

i s I A. < . | v\\ x ».\ — RELATIONS OF THE AK< II KAN OF I AN AHA.

tinuous. tunning a groat anastomosing mesh-work, the general strike being
always concave to the Lauren tiaa areas which they encircle.

Sometimes, however, where denudation has exposed their deeper portions
along anticlinal or synclinal ares, as in parts of the Lake of the Woods and
Rainy lake regions, and better in Hunter's island, the formations in contact
with the Lanrcntian granite-gneiss are found to be excessively shattered, and
countless numbers of fragments are strewn throughout the mass of the ir-
ruptive rocks. The country is well bared, and what i.- stated is clearly visi-
ble on well-exposed continuous rock surface - These included detached
fragments of the formation- overlying the granite-gneiss range in size from
piece- a few inches across to immense masse.-. Their longest diameters are.
as would be expected, in the plane of Bchistosity. Where the enclosing rock
is gneissic, the inclusions have usually a constant orientation parallel to the
foliation of the gneiss, which also coincide-, a- a ride, with the nearest edge
of the Ink through which it breaks, where not too remote from the edge.
Other inclusions in the Lauren tian have beeu observed whose derivation
from the Ontarian rocks cannot he established. Suggestions as to their
origin have been thrown out by the writer in his report on the Rainy lake
on.

Along the edges of the belts of the Ontarian rocks, there may frequently
he observed, running out from the main belt and in continuous strike with
it. tou-ue- of Bchisl which taper more or less gradually and eventually end
in point.-. These also are seen to be immersed and congealed in the granite-
gneiss; and many of the larger detached inclusions are doubtless portions
of such tongues which have In-eii separated from the main belt by the low-
ering of the plane of surface truncation by denudation, rather than by actual
detachmenl at the time of disturbance. This would in a large measure
amount for the fact that the common orientation of the larg< r fragments,
ami their parallelism with the edge of the belt, holds tor the dip as well as
tin- strike.

Numerous long, attenuated, parallel tongues are also formed at the edges
of the schist belts by the injection along the planes of schistosity of portions
of the granite-gneiss magma, forming an evenly ribboned alternation which
simulates bedding. It- formation by injection is, however, sufficiently
apparent. Similar ribboned alternations are described ami figured by Bar-
rois a- occurring at the edge of the Cambrian schists of Brittany, when
pierced by irruptive granites. The detached inclusions are, also, not in-
frequently ribboned, parallel to tin schist planes, with apophyses from the
main area ot' the enclosing granite-gneiss.

If. at the base of the Ontarian system, we had bedded rocks whicl

metamorphLsm urav<- rise to crystalline limestones, quartzites, etc.. we would

\ i\ . i-

POSSIBLE OKIGIN OF PSEUDO BEDDING. 185

have these involved with the Laurentian gneiss, just as the hornblende
schists and mica schists are, and intercalations would be produced which
would, as in the case of the schists, frequently simulate interbeddiug of
quartzite or limestone, as the case might be, with the gneiss. The deception
would, of course, be intensified by subsequent further deformation of the
crust by pressure so as to be practically beyond detection, if the clue were
not followed up from a starting point where such subsequent dynamic
agencies have not obscured the true relationship. This, the writer is per-
suaded, is the explanation of many of the intimate associations of gneiss and
quartzite or limestone, whereby rocks really metamorphic sediments are so
involved and welded with rocks of plutonic irruptive origin that they have
been taken together as a simple sequence of deposited strata.

In some portions of the Laui'entiau country, which the attitude of the
flanking rocks indicates was once arched over by an anticlinal dome of the
latter, there are found patches of schist lying quite flat, or nearly so, upon
the granite, showing, in favorable cliff sections, a brecciated or intrusive
contact on the under side. These remnants seem to show that the anticlinal
dome was flat or very lowly rounded, and that only on the flanks of the
Laurentian boss did the strata composing the arch plunge down at high
angles.

Significance of Relationship. — Bearing in mind the essential distinctions
which exist between the rock formations of the Ontarian and Laurentian
systems, both as to their lithological character and their mode of occurrence}
and remembering also their relative geographical distribution, the foregoing
statement of the relationship which obtains between the two systems leads
clearly and unavoidably to this conclusion, viz., that the formations of the
Ontarian system at one time rested, as a volume of hard rocks, upon a
magma which subsequently crystallized as the Laurentian granite-gneiss ;
so that the present line of demarkation between the two systems must be
regarded as representing the trace of what was once a plane of contact
between the then crust and the magma upon which it floated.

This conclusion affords us a conception of the Archean which is ideal in
its simplicity and which gives us the key to the raveling of the mystery in
which the subject has been involved. The fact that the crust, which con-
stitutes what we now call the Ontarian system, was crumpled while it floated
on the magma ; the fact that its lower portions were shattered by disturbance
so that the magma penetrated the fissures and enclosed detached fragments ;
the fact that there were currents in the magma which arranged the inclusions
in streams and also produced the foliation of the gneiss ; the fact of contact
metamorphism — all these are incidental and concomitant circumstances of
the great essential condition of a crust resting on a magma.

But from the nature of the rocks of the Ontarian system it is clear that

IS6 A. c. r.AWSON — RELATIONS OF THE ARCHEAN OF CANADA.

they could nol have been deposited upon a magma. There must have been
a firm crusf presenting a floor upon which they were laid down. That floor,
together with portions of the system of rocks which lay piled upon it, has
disappeared. That it has sunk down to a zone of fusion and become ab-
sorbed by liquefaction in a Bub-crustal magma, which later crystallized nut
as the Lauren tian, is the only explanation that is open to us. It follows
also thai the Laurentian rocks arc younger than those of the Ontarian sys-
tem, as has been before indicated.

Prin< rPLES of ( Ilassifk V.TION.

The bearing of the tacts and conclusions recorded above upon the tax-
onomy of the Archean is apparent. The argument establishes this cardinal
principle in the classification of that great complex of rocks, viz., thai its
primary subdivision depends upon a distinction of cosmical importance be-
tween an older assemblage of altered normal surface-formed strata and a
younger assemblage of rocks resulting from the crystallization of a sub-
crustal magma.

Principles applicable to the Upper Division. — To. the upper or Ontarian
system the ordinary stratigraphical methods of classification are applicable.
The svstem separates stratigraphically into two great groups. The lower
and older, consisting of strata t'vov from volcanic admixtures, so far as has
been observed, is the Coutchiching. It resembles in its lithological charac-
ters and in it- position the Montalban of Hitchcock. The upper group,
consisting of rocks which are dominantly volcanic in composition, is the
Keewatin. It rests upon the Coutchiching in probable unconformity, the
beginning of the period in which these rocks were deposited being signalized
l>v the advent of a widespread and continued volcanic activity. This group
falls into line with the Green Mountain series in the position assigned to it
by Hitchcock. Other groups may quite possibly be discovered which will
swell the volume of the Ontarian system.

Principles applicable to the Lower Division. — In the Laurentian the ordi-
nals si ratigraphical principles of classification do not apply, since there are
no strata properly so called; and we must seek for a principle appropriate
to an assemblage of rock- essentially different in their development and
mode of occurrence from all those of the Btral igraphical column. The Lau-
rentian is not homogeneous throughout its surface distribution. It is com-
posed ofdifferenl members or masses, which, while they present wonderfully
con-taut general characters within themselves, are distincl from one another
lithologically. A Btudy of the relationship between the masses thus differen-
tiated in Bpace leads us to the chief moment of all geological classification,
namely, their differentiation in time ; and we have to consider the possibility

SUBDIVISIONS OF THE LAURENTIAN SYSTEM. 187

of different generations of Laurentian rocks. This possibility presents itself
as soon as we familiarize ourselves with the sub-crustal igneous and later
formations of the Laurentian.

Different Generations of Laurentian Rocks. — To the writer this conception
of different generations has never been more than a possibility till the present
year. In his report on the Rainy lake region, two broadly distinct mem-
bers of the Laurentian were distinguished, lithologically and on account of
their systematic relative distribution, as the " peripheral zone " and " inner
nucleus " of the Stanjikoming area, the former being composed chiefly of
hornblende-granite and syenite-gneiss, and the latter of very quartzose
biotite-gneiss. The relationship in time between these two rock masses re-
mained indeterminate. During the past summer, however, he has been able
to establish, in the Hunter's island region, chronologically distinct genera-
tions of Laurentian gneisses. In that region there are two broadly distinct
members of the Laurentian, analogous petrographically and in relative dis-
tribution to those of the Stanjikoming area. Below the Keewatin rocks
there is a great mass of hornblende-granite-gneiss, which presents an irrup-
tive or intrusive contact against them. Towards the central part of Hun-
ter's island this hornblende-gran ite-gneiss is pierced by an enormous irrup-
tion of biotite-granite, which is sometimes very distinctly gneissic and
sometimes quite undifferentiated in structure. In texture it varies from
fine-grained, almost micro-granitic, to a moderately coarse granite. This
biotite-granite-gneiss traverses the hornblende-grauite-gneiss in innumerable
clearly defined dikes cutting it in all directions, and holds innumerable in-
cluded blocks of the same rock. It comes up from beneath the hornblende-
granite-gneiss, and is unquestionably of later age.

Thus we have in this area at least two distinct generations of Laurentian
rocks, both the result of the crystallization of a sub-crustal magma. At the
time of the second generation the rocks of the first generation constituted
the lower portion of the crust.

It is upon the recognition of facts of this order that an intelligible and
profitable classification of the Laurentian rock masses and the geological
events which they represent must be established.

Other Conditions considered. — The relationship which has been found to
obtain between the upper and lower Archean leads, as has been said, to a
conception which is at once grand and simple. So long as we confine our-
selves to regions like that northwest of Lake Superior, where no great com-
plications have been introduced by post-Archean crust-crumpling agencies,
it affords a full explanation of all the phenomena of Archean geology.

There is a possible simpler case which would still present the essential
conditions of the relationship in question ; i. e., the case in which the sub-

XXV— Bull. Gkol. Soc. Am., Vol. 1, 1889.

1SN> A. C. LAWSON — RELATIONS OF THE ARCHEAN OF CANADA.

crustal magma mighl be irrupted within the overlying crustal rocks without
the intense folding of the latter. Here we should expect to find a less pro-
nounced alteration, due only to the proximity of the magma, and an absence
of those phases of metamorphism which accompany the rock shearing, crush-
ing, and stretching due to dynamic agencies, [n the common case, where
the upper crustal rocks are folded, varying phenomena would also be ob-
served according as the folding took place before the fusion which produced
the magma immediately beneath the crust or while the latter was Boating
upon the magma.

There are also more complicated cases which are doubtless common.
These are due to the superimposed action of crust-crumpling, rock-shearing,
strata-squeezing forces subsequent to the establishment of the Archean con-
ditions in their primal simplicity. These are possibilities which must be
borne in mind in attempts to apply the theory lure advanced to the Archean
in other regions. It is easily conceivable that had the country northwest of
Lake Superior been subjected to extensive deformation in post-Archean
times, the evidence whereby the irruptive character of the Laurentian has

been demonstrated might have been entirely obscured, and the true relation-
ship might have remained unsuspected, as appears to have been the case in
better known regions.

Similar Observations elsewhere.

In various parts of the world observations have been recorded which show
that the phenomena arising from the irruption of a local or general sub-
crusta] magma through an overlying crust, and the consequent development
of a complex of gneissic igneous rocks and metamorphic strata, are not
peculiar to the region studied by the writer.

MacFarlane* long ago described and figured good evidence of the irrup-
tive character of the Laurentian of the northeast shore of Lake Superior;
but, iii accordance with the views of the extreme plutonic school, he regarded

the whole complex of intrU8ive and intruded mcks as the first crust of the

earth, and the angular fragments of hornblende schist a- earlier separations
from the same magma a- thai which crystallized into the Laurentian granite
or Byenite-gni iss.

Mr. Prank Adam-, who ha- been for some years past engaged in a atudj

of the Laurentian of the Province of Quebec, north of the St. Lawrence,

—

The unexpected fact wa lined thai the so-called massive and Btra titled

ilu- rock [anortbosite ; hithert< led :e upper Laurentian and meta-

3., Vol. Ill, 1867, p. 177.

OBSERVATIONS IX EASTERN CANADA AND EUROPE. 189

morphicj are in reality only different portions of one and the same mass. * * * As
a result of this summer's work, I think it may be safely concluded that the rocks com-
prising the principal area of anorthosite above referred to, as well as most, if not all,
of the smaller areas, are of eruptive origin." *

He confirms this in his summary for 1888 in the following words : —

" All the areas of anorthosite now known to occur in the district have been ex-
amined, and mapped, and have proved to be either eruptive masses cutting through
the gneisses, or masses interstratified with the latter, but probably still of eruptive
origin." f

Callaway has shown, in his paper on the granitic and schistose rocks of
northern Donegal, that the granite-gneisses of that region, which have been
regarded as Laurentian and which correspond closely in lithological
characters and mode of occurrence with the Laurentian of Canada, are really
irruptive through older- rocks, which must have arched them over, and present
all the evidences of irruption which have been adduced by the writer in
support of the irruptive origin of the Laurentian northwest of Lake Superior.
He thus states his conclusions: —

"1. The granite rock of northern Donegal, originally supposed to be the result of
the metamorphism of sediments, and recently referred to the Laurentian system, is a
true igneous granite, as seen in its intrusion into the adjacent schists, in its inclusions
of masses and fragments of other rocks, and in its metamorphic action on limestone
in contact. 2. This granite is distinctly foliated, the gneissic structure being caused
by lateral pressure, * * * 3. The granite is intrusive in a thick group of quartz-
ites, quartz-schists, hornblendic, micaceous and talcose (?) schists, and crystalline
limestones, called the Kilmacrenan series. These rocks are truly crystalline, but
usually thin-bedded and fine-grained. 4. The crystalline schists are bounded on the
east by a semi-crystalline series, consisting of quartzose grits and itacolumites, quartz-
ites, crystalline limestones, compact dolomites, phyllites, interlaminations of grit and
schistose matter, and finely foliated micaceous schists." J

These conclusions as to the irruptive origin of the gneiss are confirmed by
later observations of the same investigator on the Galway gneiss. §

In the pre-Cambrian or Archean of Brittany, Barrois recognizes the irrup-
tive character of the gneisses which correspond to our Laurentian. He

says —

" Ces gneiss alternent avec des lits interstratifies de micaschistes et d'amphibolites,
et passent a des granites gneissiques qui les penetrant a la facon d'une roche eruptive.
L'ensemble des gneiss et micaschistes granitiques avec granites gneissiques rappelle par
ses caracteres lithologiques L'etage dimetien, propose par M. Hicks, dans le pays
de Galles, le gneiss fondamental d'Ecosse, certains gneiss laurentiens du Canada,

*Geol. Survey of Canada, Summary Report for 1887 and 1888, 1889, p. -27a.

t Ibid., p. 85a.

{Quart. Jour. Geol. Soe., Vol. XLI, 1885, p. 239.

I Quart. Jour. Geol. Soe., Vol. XLIII, 1887, p. 517.

L90 A. C. LAWSON — RELATIONS OF Till-: A.RCHEAN OP CANADA.

* * *. lis [micaschistes] y alternent avec des lit-- subordonnes de gneiss a grains
fins, d'ampbibolites, de chlorito schistes, de schistes micaces, et comprennent des
masses interstratifiees de diorites el de granulites, d'origine eruptive. Ccs roches
subordonnees for men t avec los micaschistes, dans lesquels elles sont injectees, de
longues bandes paralleles, * * *."*

Newton's description of the geology of the Black Hills of Dakota i haves
little room for doubt hut that the rucks which he calls Archean correspond
to the upper Archean or Ontarian system of central Canada, and that his
irruptive granite, though not described as foliated, is the analogue of the
commonest phase of the Laurentian. The same relationship holds between
the two rock systems in both regions, and many of the Laurentian granites
are devoid of foliation.

Geognostical Equivalents of the Archean.

In assemblages of rocks of indeterminate or post-Archean age complexes
of gneissic irruptive rocks and older metamorphic strata of elastic or vol-
canic origin are now well known. These cannot be Bpokenofas the geolog-
ical equivalents of the Archean complex on account of their diverse age, but
may he referred to as Its geognostical equivalents, since their development
appears to depend upon universal sub-crustal conditions, which are to a large
extent independent of geological age.

M<Mahoii,i in his studies of the great " central gneiss" formation of the
Himalaya mountains, has demonstrated clearly that the formation is not, as
was long Bupposed, the Archean basement upon which the Paleozoic sedi-
ments were deposited, hut is an irruptive mas- breaking up through the
Silurian and later rocks, altering them, holding detached fragments of their
strata, and being injected within the strata. Speaking of this formation,
which he ••all- gneissose granite, he cites the following evidences in proof ol
it.- irruptive- origin : 1. The granite has produced a certain amount of con-
tact metamorphism on tic rock.- touching it. 2. Tongue- and intrusive
veins have been sent from the granite into the adjoining rocks; in other
places the granite appears in Bheets between the he. Is of the sedimentary
rock.- ;it -nine distance from the junction of the latter with the main mass ol
the granite, and in -one cases these Bheets or dike- have cut through the
beds and passed from one horizon to another. 3. The main ma-- of the
granite appears at different geological horizons. § 1. The granite < tains

Hull. Si i'-. I XIV, 18*

y and Resouxcea "i the Black Bills <>i Dakota. By Benry Newton and
Walter I'. Jem

rvej of I. ..i i:.. i: >k Vol. .Will, Pari I, 1884, p 108 ibid., Vol. XVIII, Pari 2, 1886,

Oeol. Mag Dec ide III, \ ol. IV, 1887, p. 212.

t does wl • tbe !<• tod al another against the Cout-

liinR in i' on.

GKANITIC IRRUPTIONS OF VARIOUS AGES. 191

veins similar to those caused by shrinkage on cooling in granite of admit-
tedly eruptive origin. 5. It contains fragments of slates and schists im-
bedded in it. He also states that the evidence afforded by the study of thin
slices confirms the conclusion arrived at by the stratigraphical evidence, and
gives a summary of the microscopic evidence.*

The very able and precise descriptions by Barroisf of the various granitic
irruptions which have affected Brittany at different ages from the pre-Cam-
brian up to the Carboniferous show beyond question that not only in
Archean times, but at various subsequent periods were the conditions
which characterize the Archean of Canada reproduced. He describes par-
ticularly the "granite gneissique," demonstrates its irruptive origin, and
notes not only the contact metamorphism, but also the injection of these
rocks " en filonnets minces et repetes " within the encasing schists. His
descriptions and figures of repeated injections of granite within the schists,
so as to produce an alternation simulating bedding, closely corresponds with
the contact phenomena described by the writer as observed between the
Laurentian and Keewatin on the Lake of the Woods, the interpretation of
which is entirely in accord with that of Barrois, though questioned by Pro-
fessor A. Winchell.J It would appear that just as in Hunter's island, north-
west of Lake Superior, we have two generations of Laurentian rocks from a
sub-crustal magma, so in Brittany there have been several generations of
similar rocks breaking through the overlying crust, extending in time as
late as the Carboniferous.

In Norway Kjerulf $ places the " Gebanderte granit, oder gneisgranit "
with the eruptive rocks, and states that in numberless places such rocks
break through the strata of the gruudgebirges, and also, indeed, through the
Bergenschiefer in which Reusch has since found Silurian fossils. |j In the
greater part of Norway he says (translated freely) ^[ —

" What was formerly recognized as gneiss must on the map he now designated as
granite. The reason why the older observei-s assume it to be gneiss is the granular
banded structure, which we must distinguish from the appearance of bedding. On
older maps are shown also other great regions in which the dip and strike of the beds
is given, an attribute which they do not in reality possess; and the reason for this
lies in the confounding of foliation with bedding. * * * The rock, according to
the old conception, is granite when no bedding occurs in it. The modern view,
which had already been announced by Delesse, says : ' En realite c'est [le gneiss granit]
seulement une variete du granit, qui est veinee et qui parait avoir ete genee dans sa
cristallisation.' " **

*Geol. Mag., loc. cit.

fBull. Soc. Geol. de France, 3me Serie, t. XIV, 1886, pp. 655-898.

j Geol. Survey of Minnesota, Fifteenth Annual Report, 1886, p. 201, \ 5.

§ Die Geologie des Sud. und Mit. Norwegen, Bonn, 1880, p. 237.

|| Fossilien Fiihrenden Schiefer von Bergen, Leipsig, 1883.

If Op. cit. p. 282.

** Delesse, Etudes sur le Metamorphism, 1861.

1 92 A. C. I.AW.-uN — RELATIONS OF THE A i;< II KAN OF CANADA.

The Byenites of the southeast coasl of Norway, also, which have been studied
particularly by Brogger, and which arc irruptive through fossiliferous
Silurian and Devonian strata, arc eminently gneissic in places. They are in-
distinguishable in this respect from the more distinctly foliated varieties of
our Laureiitian gneiss.

Lehman's masterly work* on the rocks of Saxony and other geologically
similar regions has clearly established that many of the gneisses of central
Europe are irruptive in their origin.

The foliated gabbros or gabbro-gneisses of the Lizard are regarded a>
eruptive by such eminent observers as Teallf and McMahon,J though they
differ as to the precise mode of the development of the foliation.

Harper § has shown that the "granite and gneissic granite" df Lam,
( !aernarvonshire, which was formerly held to he Archean, is in reality irrup-
tive and of more recent age than the Upper Areuig strata :

The actual contact of the two rocks is easily found, and the granite is seen to send
out little tongues between the laminae of the shale. Specimens of the latter reek,
indurated and firmly adhering to the granite, may be obtained. * * * The Bhale
is clearly altered and exhibits little spots and nodules supposed to represent the in-
cipient development of chiastolite. Another quarry, well within the boundary of
the granite, shows entangled masses of baked shales."

In a paper submitted to the International Geological Congress at its Lon-
don session j| in L888, the writer quoted Dr. G. M. Dawson • at some length
tH -how how entirely the conditions which obtain between the Triassic rocks
of the west coasl and the younger subjacent irruptive granite are analogous
to those which obtain between the rocks of the upper Archean or Ontarian
system and the Laureiitian granite gneiss. Dr. Dawson's account of the
history of geological events in that region in post-Triassic times confirms
the correctness of the writer's interpretation of the Archean of central
( lanada.

The interesting nostical equivalent of the Archean on the Pacific

coast is paralleled on the Atlantic coast by the great irruption of "gneissic
granites" which in post-Cambrian times, possibly as late as the Devonian,
have broken up through the Cambrian Blates and quartzitee These

oeissic granites" are indistinguisable from many of the Laureiitian
gn< is8< a.

atersuchungen Qber die ESntatehung der altkrystalllnischen Schlefergesteine, Bonn, 1881

M)rlij I Mag., N. 8., Decade III, Vol. IV, 1887, p. 484.

[On ( he Foliation •■! i In Id , p 71.

et. Jour. ' , \ ol. XXXI V. 1878, p. u:

I
i i \ nnual itepoi t, 1887, Pari B, pp 1 1 1 :

rouRh and Halifax Countie By E. K. Faribault;

i Annual Report, i

The Argument from Analogy.

These references and quotations by no means exhaust the literature of
the subject. They are taken mostly from very recent writings, and much
to the same effect might be quoted from the older geologists, such as Von
Cotta, Neumann, Darwin, Delesse, and others, who have insisted on the ir-
ruptive character of gneissic rocks or have regarded gneiss as but a differ-
entiated variety of irruptive granite. But enough has been adduced to
show that the writer's interpretation of the Archean geology of central
Canada, in so far as it depends upon the irruptive nature of the Laurentian
gneisses, is not without the strong support of many analogies.

(193)

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA

VOL. 1, PP. 195-202; PL. 3

STRUCTURE AND ORIGIN OF GLACIAL SAND PLAINS

WILLIAM MORRIS DAVIS

WASHINGTON
PUBLISHED BY THE SOCIETY

March, 1890

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA
Vol. 1, pp. 195-202, pl. 3 March 21, 1890

STRUCTURE AND ORIGIN OF GLACIAL SAND PLAINS.

BY WILLIAM MORRIS DAVIS OF HARVARD COLLEGE.
[Read by title befm-c the Society December 27, 1889.)

CONTENTS.

Page

External Form and Internal Structure 195

Hypothesis of Origin 106

Deductive Extension of the Hypothesis " 196

Verification of the Hypothesis 107

Evidence from Cross-bedding 1- 198

Katio of Sand-plain Growth to Ice Melting 199

Origin of Depressions in Sand Plains 199

Local and Temporary Growth of Sand Plains 200

Sand Plains generally formed in local Bodies of Fresh Water 201

Relation of Sand Plains to other Glacial Deposits 201

Points needing; further observation . 202

External Form and Internal Structure. — Plains of stratified gravelly sand,
half a mile or more in diameter, standing mesa-like above the adjacent
valley ground, are common in many parts of New England. They lie on
striated ledges and till, and hence are at most not older than the closing
stages of the latest glacial epoch. Their distinct marginal slopes give no
indication of more than a small measure of erosion, and hence their present
form may be taken as essentially equivalent to their initial constructional
form. They are well stratified throughout, and this, along with their defi-
nite marginal slope, indicates them to be deposits made in bodies of standing
water.

The general surface of these sand plains is very even, but fails of being
level by reason of a gentle slope, generally to the south, of ten, twenty, or
thirty feet to the mile. Their margins are in most cases well defined, having
slopes of from 10° to 30°. They present two very distinct forms of outline,
illustrated in plate 3. The northern quarter of the perimeter possesses a
number of strongly concave curves, descending by steep slopes to kettle-
hollows, often holding swamps or ponds; and the cusp-like points between
these curves extend northward into a group of gravelly ridges and sandy

XXVI— Butt. Geol. Soc. Am., Vot,. 1, 1889. (195)

L96 W. M. DAVI! GLACIAL SAND PLAINS.

hillocks — eskers and kames. The other three-quarters of the perimeter,
turned to the Bouth, is even more Btrongly characterized by a number of
convex lobes and sub-lol iarated by re-entranl interlobate hollows.

The internal Btructure of the plains, where revealed by railroad cuts and
Band pits, consists In greatest part of obliquely deposited beds of .-and. or
occasionally of sandy gravels, dipping towards the lobate margin al an angle
of from 20 to 25c : Inn these are covered by gravelly or sandy cross-bedded
horizontal layer- to a depth of from five to fifteen or more feet; and the
thickness and coarseness of this cover appears to increase towards the esker
and kame margin.

Hypothesis of Origin. — In view of these facts of form and Btructure, it is
difficult to find any explanation for our .-and plains other than the one gen-
erally current, which regards them as delta-like deposits of sand and gravel,
washed in the closing stages of the last glacial epoch from the irregular front
of the melting, stagnant ice-sheet into bodies of water that bathed its edge.
Before looking further at the facts, let us extend this hypothesis as far as
possible to its consequences, and then test its correctness by the complication
of correspondence between deduction and observation.

Deductive Extension of the Hypothesis. — The former existence of an ice-
-heet over New England i- accepted as evidence that is entirely independent
of the occurrence of Band plains. The ice-sheet is now gone; and between
the times of its greatest thickness and fastest motion and of its 'entire disap-
pearance it must have been reduced to a thickness at which motion was im-
possible; then it lay passive and stagnant, as Chamberlin has pointed out,"
for the remainder of its existence; during this time it must have melted irr<
ularly, presenting a very uneven, ragged front, from which residual blocks
may have been frequently isolated: and it must have endured longest in
the valhy-. where it was thickest, not only by reason of it- greater depth,
hut also because it- surface there, where motion had Keen fastest ami longest
maintained, must have been higher than on the hill- —this being homologous

with the variation in the thickness of a Swi<- valley glacier from middle to

-id.

A melting ice-sheet must have frequently embarrassed the drainage of the
BUrface on which it lay; ponds would accumulate in hollows and vallt
sloping towards it. a- I rphara ami Met ice have indicated, and after Btanding
lor a time at a level determined by one line of overflow they must have sud-
denly fallen or drained away a- m-w outlet- were opened by the melting of
the ice, thus causing active floods. Near the coasl a moderate (relative de-
pression of the land seems to have brought standing sea water against tin'
ten or twenty mile- inland from the present shore-line.

Wherever active, drift-laden Btreams ran from the melting ice into Btand-
ing water at it- margin, their velocity must have been checked and all but

DEPOSITS FORMED AT THE ICE MARGIN. l'.l<

the finest part of then- load dropped. The channels leading strong streams
to the margin might receive esker-like deposits of coarse gravels and sand
irregularly deposited ; the open spaces near the ice margin, containing waters
of gentler movement, would become choked with kame-like mounds of finer
sand; and where streams of either class ran from the ice to the water in
front of it, sand deltas must have grown with greater or less rapidity. Their
growth would be in three directions. They would grow forward by con-
tinued addition of oblique layers to their sloping front; as the front ad-
vanced they would slowly grow upward by the addition of essentially hori-
zontal layers, after the fashion of ordinary deltas, in order to maintain a
gentle surface slope from head to front; and as the ice melted awray, the
space that it evacuated at the head of the delta would be more or less com-
pletely filled by a backward growth at that part. If the feeding streams came
from beneath the ice they must needs rise to flow over the delta surface to
its front, and hence the backward growth at the head must have been at
such points in the form of up-hill deposition. These three classes of deposits
may be called fore-set, top-set, and back-set beds, shown in fig. 1 ; and it is

F~0 UND /^\~T [C?l^i .

Figure 1.— Ideal Longitudinal Section of a Sand Plain.

manifest that the ratio of fore-sets to back-sets must be the same as the ratio
of the forward growth of the delta to the backward melting of the ice.

When re-arrangement of glacial drainage leads the feeding streams away
to some other outlet, and when later meltiug or elevations of the land allows
the marginal waters to drain away, the deltas previously formed stand up
somewhat above the adjacent surfaces ; the steep, concave outlines of the
head of a plain, with its feeding eskers, kames, and kettles, mark the irreg-
ular margin of the melting ice; and the convex lobes of the front of a plain
mark the growing front of the delta.

Verification of the Hypothesis. — The general correspondence of the fore-
going deductions with the facts is a sufficient assurance that our search for
explanation is in the right direction ; but certain facts of structure need re-
examination in the light given by our theoretical suggestions. Is there any
direct indication that the front of the plain grew forward by down-hill depo-
sition, while the head grew backward by up-hill deposition? The fine cross-
bedding frequently characteristic of both the fore-set and back-set beds leaves
no doubt on this point, when its significance is clearly perceived ; and for
this a brief digression is needed.

L98

M. DAVI: GLACIAL SAND PLAINS.

/ idena from Cross-bedding. — Normal oblique deposition may be typified
in fig. "_', from which it appears that every bed presents ;i convex upper

portion, a />, and a concave lower portion, c d, joined 1>\- a tangent, l> e.
When a change of current carries away the upper part of such a deposit
abov( the line e /, tin- upper convex curve is destroyed ami only part of the
tangent and the concave curve remain : and when a later change brings
additional deposits, these lie with their concave lower curve.- tangent to the
surface of truncation of the earlier beds. It does not appear that the forms

Figure 2. — Ideal Si I ling.

and relative position of such beds would be changed, whether they are laid
down on a descending or an ascending surface : the only essential condition
of their growth is the presence of a stream of varying power and load, but
on the whole of greater load than power. Back-set and fore-set beds should,

their lore, t u in the concavity of their cross-beds in the direction of the stream
that formed them — that is, in the direction from the head to the front of the
plain.

Figs. •'! and 1 are from sketches made of the back-sel beds at the head of
a -ami plain in Newtonville, and of the fore sel beds at the extremity of a

THE ORIGIN OF CROSS-BEDDING. 199

frontal lobe of a sand plain near Wakefield, both in eastern Massachusetts.
It is manifest that both were built by a stream moving to the right in the
figure. This corresponds to the direction from head to front of the plains,
and indicates that the back-sets were built by an ascending stream, rising

Figure 4.— Cross-bedding at the Front of a Sand Plain.

from beneath the ice to the top of the delta plain, while the fore-sets were
built by a descending stream, flowing from the plain into the water at its
front.

Ratio of Sand-plain Groivth to Ice Melting. — The ratio of fore-set and back-
set beds is of interest, for, as already stated, it indicates the ratio of the for-
ward growth of the delta to the backward melting of the ice. The sections
thus far examined do not furnish final numerical results ; but enough has
been seen to make it clear that the fore-sets are from ten to forty or fifty
times as extensive as the back-sets, and from this it appears that the melting
of the ice was slow compared to the growth of the delta plain.

Origin of Depressions in Sand Plains. — This conclusion is of value in ex-
plaining the pits, kettles, and irregular depressions that frequently interrupt
the otherwise level surface of the plain. The theory has long been current
that these pits were the sites of isolated blocks of ice, around which the sands
of the plain were deposited ; but it has also been currently objected to such
an explanation that it involved an improbable and unproved rapidity of
sand-plain growth. The conclusion just gained from the ratio of the fore-
sets to the back-sets overcomes this objection. No satisfactory section of the
slopes of a pit has, however, yet been found to give more direct evidence on
this question.

2Q0 W. M. DAVIS — GLACIAL SANO PLAINS.

/. *cal and Temporary Growth of Sand Plains. — A corollary of the rapid

iwth of the delta plains compared to the retreat of the ice is, thai the
growth of delta plain.- was a local, temporary, and spasmodic operation ; for
if it had been general, persistent, and continuous, the plain- must have been
of vastly greater extent than we find them. It is true that, in front of the

at terminal moraines, there is a wide-spreading; sand plain; hnt here,
however intermittent its growth may have been, its locus of deposition was
maintained within narrow limits for a long time. Such was not the case
with the sand plains that are dotted over New England; they were formed
as the i<e w;i- on the whole retreating; and yet. in spite of their rapid
advance compared to its retreat, they occupy hut a -mall part of the
country — not more than a twentieth and probably much less. The stand-
ing water in which they were built was seldom completely tilled tip, lor their
frontal .-lope- commonly descend into meadow-, often of large extent.

In searching for the cause of the local character and brief duration of
their growth, we can hardly expect to find it in the cessation of outward
drainage from the retreating ice-sheet, or in the discharge of saud-laden
stream- at one time and clear-water streams at another. A more probable
explanation looks to the variation in the point of discharge of the Bub-glacial
Streams. The larger rivers were presumably fixed, hut the smaller ones
must have frequently changed their courses. Winn they discharged into
valleys sloping away from the ice front, the valleys became clogged with

ivel and sand, stretching far down stream, to lie terraced later on; hut
when they discharged into valleys of northward slope they were ponded
hack, ami their deposits were concentrated in their deltas, until a change in
the point of escape was made, when similar processes went on elsewhere.

It is not uncommon to find the frontal lobes of a .-and plain lying on
kame mound- and e-ker ridges of earlier origin, as at the BOUthwest front of
plate •'!. The same relation must often occur within the plain. It finds
illustration in a valuable section on the Belt Line of the Boston and Albany
railroad, a mile BOUth of A n In inula I e, which -hows I lie triangular outline of
a Btony e-ker buried in the fun Bel -and lied- of a plain. Tin- edge of the

must have been south of this point when the esker was formed, and th

of it w hen the sand plain was built; and between these two date- there must
have I.e. n a time of very -mall deposition hereabouts, for kick set beds are
wantin

The coarse, ■_ ravelly character of the top-set beds of saud plains is a natural
result of the continued selective process tli.it must have gone on over the
:ace during their deposition. The gravelly beds represent the residual
material left in the beds of shifting and branching delta stream-, the _

pari of the material of liner texture having gone forward to build out the

front ..f the ddia. In the same way the co irs< . water-worn material of the

with it- frequently loosi arrangement and very imperfect stratifica-

PHYSIOGRAPHIC CONDITIONS OF SAND-PLAIN FORMATION. 201

tion, indicates that here also much more detritus was carried along than was
laid down. The sand-plain front was the goal at which most of the detritus
stopped, and hence its rapid growth. The clay beds that we should expect
to find as the final deposits of the glacial streams probably occupy the
meadow bottoms in front of the sand plains ; but as yet no sections clearly
manifesting the relation of the clay to the sand plains have been found.

Sand Plains generally formed in local Bodies of Fresh Water. — Near the
coast, and up to an elevation of fifty or a hundred feet above present sea
level, in eastern Massachusetts, the water in which the sand plains were built
appears to have been ocean water; but the amount of submergence thus sur-
mised has not yet been fully worked out. Further inland, where plains are
found up to altitudes of a thousand or more feet above sea level, I think
the water in which they accumulated w^as fresh water, temporarily ponded
by the ice front. The reasons for this opinion are as follows:

The ice of the last glacial epoch appears to have melted off of the country
first in the southern and later in the northern part of its area, producing a
general northward migration of the locus of sand-plain formation. Accepting
the generally current idea that the depression of the land diminished as the ice
retreated, it follows that the sand plains of later date should be of less eleva-
tion above present sea level than the earlier ones, if they were all deposited
in ocean water ; and this is not the fact. The sand plains of the interior
and northern part of New England, which must have been built at a rela-
tively late stage of ice melting, are of distinctly greater elevation above
existing sea level than those near the coast, which must have been built at
an earlier date. The interior sand plains are therefore regarded as having
been accumulated in local and temporary ponds, determined by the ever-
changing relation of the rock and drift topography to the frontal margin of
the retreating ice. Otherwise it would be necessary to suppose that the
submergence of the land increased as the ice melted away ; and while this
is manifestly not to be regarded as geologically impossible, it does not appear
to be accordant with the general results of glacial study thus far obtained.

Relation of Sand Plains to other Glacial Deposits. — The relation of glacial
sand plains to two other similar forms of late or post-glacial deposits may be
briefly mentioned. In many cases the streams from the ice ran down open
valleys, and not into ponds of standing water. In such cases the valleys
were commonly clogged with flood-plain deposits of sand and gravel, often
of great extent. These are unlike the glacial sand plains in having no defi-
nite frontal slope, and hence in wanting also the steep-dipping fore-set beds,
of which the frontal slope is the external expression. The flood-plains are
indeed merely extended illustrations of what I have called the top-set beds
of the sand plains; but their connection with the back-set beds, which theory
leads me to suppose must exist, has not been traced out. The original flood-
plain, now the upper terrace, of the Merrimac, as described by Upham, in

■^rj, \v. \|. DAVIS — GLACIAL SAND PLAINS.

New Hampshire, is a large example of this kind. The sand and gravel
plain of Rock river in southern Wisconsin appears, from its descriptions and
from the brief sight that I have had of it, to be another. As a natural con-
f the change from the conditions of their formation to their present
conditions it follows thai valley flood-plains are now commonly terraced by
the Btreams that formed them, while sand plains proper are nearly always
avoided by streams.

The other deposits that simulate the glacial sand plains are the stream
delta-, formed normally in the ponds that temporarily fringed the ice front.
Following Upham again, I have been led t<> an excellent illustration of these
deposits in the ( lontoocook valley in southern New Hampshire, where a lake

of< siderahle size was ponded hack by the ice. The streams that enter this

valley tunned deltas of several acres in extent when they entered the hike,
and these deltas are now found perched up. at an accordant altitude, on the
p hill-slopes that enclose the valley : and at thesame level, stony benchi 3,
sandy beaches, and linear bars may easily be traced lor many miles. Emer-
has described similar stream deltas in the Connecticut valley. Like
the valley flood-plains, these normal Btream deltas are now commonly cut
through by the streams that made them. Like the glacial sand plains, they
present Btrongly marked frontal slopes, but, unlike them, they are built out
from a solid hind support, againsl which they still rest, while the support
from which the glacial -and plain- grew ha- vanished away.

Points needing further Observation. — The search for structural features of
sand plains 'in which I have been aided by several students, especially
Messrs. Ropes and Stone, of the class of L889 at Harvard College, and by

Mr. Gage, a Bpecial Btudent) has not yet discovered any example- of the
superposition of -and plain beds on their foundation of till ; the statement

already made to the effect that such is the order of deposit is based partly
on the doI infrequent protrusion of glaciated rocky knobs above the surface
of a plain, and partly on the apparent overlapping of till slope- by sand-
plain lobes. Nor has the point of change from back-set to fore-set beds been

found in any cut yet visited: hut the occurrence of fore-sel beds close up
to the head of several plain- -how- clearly enough that very little room

can he left for the back-sets. No Section of the slopes of a pit within the

plain ha- vet been discovered; the nearest approach to this was the finding
of a -mall huried pit aboul fifteen feet in diameter— that is, a pit that had
been filled by subsequent deposit of top-set beds; this showed distinct down-
faulting of the marginal beds, a- if some local Bupporl had been withdrawn

from below them, and thifl i- interpreted as indicating the melting away of

a -mall ice block, after some of the top-sets had been Bpread over it, and
before the building of the plain had ceased.

Whei r search ha- been carried further, we shall attempt a fuller state-
ment of the case, with detailed illustration of many sections and various
Band plain

BULL. GEOL SOC. AM.

VOL. 1, 1889,

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A REPRESENTATIVE GLACIAL SAND PLAIN.

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA

VOL. 1, PP. 203-244; PLS. 4, 5

THE PRE-CAMBRIAN ROCK OF THE BLACK HILLS

C. R. VAN HISE

WASHINGTON
PUBLISHED BY THE SOCIETY

March, 1890

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA
VOL. 1, PP. 203-244,, PLS. 4, 5 MARCH 26, 1890

THE PRE-CAMBRIAN ROCKS OF THE BLACK HILLS.

BY C. R. VAN HISE.
[Read by title before the Society December 28, 1889.)

CONTENTS.

Page.

Previous Work 203

Scope of Paper 204

Distribution and Structure of the Bocks . 20G

Origin of the Granite 210

Age of the Granite 212

Permanency of Clastic Characters in Rocks 218

Lilhological Divisions _i 214

The Conglomerates and Quartzites 215

The Mica-slates and Mica-schists 222

The Mica-gneisses 226

Garnet, Staurolite, and Tourmaline 227

Other Crystalline Rocks 220

Nature of Original Sediment 230

Bearing of Microscopical Study upon the Origin of the Granite 231

Bedding, Cleavage and Foliation -_. 232

Correlation . 234

Sum mar v of Conclusions 240

Previous Work.

Apparently Dr. Hayden ';: and Professor N. H. Winchell f were the earliest
geologists to visit, the Black Hills of Dakota; the former while engaged in
his extended surveys in the Northwest, the latter as the geologist of General
Custer's expedition of 1874. The works of both in this region were no more
than reconnaissances, and the pre-Cambriau rocks received comparatively
little attention.

One of the consequences of these preliminary trips and exaggerated re-
ports as to the richness of the hills in gold was a systematic survey of the

*On the Geology and Natural History of the Upper Missouri, F. V. Hayden : Trans. Am. Phil.
Soc, 1861, pp. 218. This was Dr. Haydeu's most complete account of the Black Hills region, and
sums up the results of his previous reports.

f Geological Report on the Black Hills of Dakota, with map, by N. H. Winchell. Contained in
"A Report of a Reconnaissance of the Black Hills ot Dakota," made in the summer of 1S74, by
William Ludlow; 1875, pp. 21-60.

XXVII— Bull. Geol. Soc. Am., Vol. 1, 1889. (203)

204 C. K. VAN HISE — PRE-CAMBRIAN OF THE BLACK HILLS.

area by the Rocky Mountain division of the United States < reological Survey
under the direction of Major Powell. This work was entrusted to Messrs.
Henry N< wton and Walter P. Jenney— Newtou as geologist and Jenney as
mining expert. Newton's death occurred before Ids report was ready for
the printer, and it was edited by Mr. G. K.Gilbert. The large monograph*
which appeared as the result of Newton and Jenney's field-work contains,
besides their reports, chapters by Whitfield. Caswell, Gray, and Tuttle upon
their respectn From the time of its appearance this work has

ii the great authority on Black Hills geology, and of it- excellenci
which are due alike to the ability of Newton and the skill and insight "I' the
editor, all later geological visit »rs to the Black Hills have spoken.

Work in this region subsequ ml to that of Newton and Jenney has been
in the nature of various brief visits by different geologists for particular
objects. Devereux f speaks of the geology of the Black Hills in connection
with the origin of certain gold ores. EmmonsJ gives a brief geological
Bketch of the region in the Tenth Census reports. Blake, § in Mineral
Resources of the United States, makes a u-w remarks on its geology. The
most important articles from a geological point of view, however, which have

appeared due,' Newton and Jenney'.- m igraph are by Crosby and Car.

I„iiter.* Their field-work was done together, and their articles have many
point- in common.

Scope of Paper.

The present paper is based upon a visit to the Black Hills during the

.-mi -r of 1889. Like those who have preceded me, since the time of

Newton and Jenney, my object was specific rather than geueralin its nature.
In the field-work I had tic assi tance of Professor C. W. Hall. I am also
indebted to IV >f - >rs I'. R. Carpenter and William I*. Headden, and Mr.
Tii' Kuntz ai, all of the Dakota Sch 10I of Mines, for important informa-

tion as to localities and roads, while Professor Headden kindly made an
i 1 1 -, » the relations of the Cambrian sandstone and the granite

in the vicinity of Hayward. No attempt was ma le to study the formations
of the Hill- or t» revise the .• inclusions that had been before reached, with
the exception of the pre < lambriaa rocks. Tl ailed A.rchean core, using

the term of Newton, was traversed from north to south and east to west.

i is. By Henrj

' reu \ :
of the United

W. l'. : ' I, pp

HUt.. Vol \ \ II '

i| of Min '

Mill lllu, Hoffra in. i---. pp, 171.

NEWTON S MAP OF THE BLACK HILLS NUCLEUS.

205

Very numerous specimens were collected, from which thin sections have been
made. The objects of the study were, to ascertain the basis upon which these
rocks are divided into two series; to get, if possible, some idea of their
structure; to compare them with those of other pre-Cambrian areas; and,
finally, to attempt to get at the genesis of the crystalline schists there exposed.

i-)!rvJ Granite

S*:SSSa Modern Volcanics

Carboniferous

Cambrian

Slate.

Schist

Scale of Miles.

OS 4 O S JO 32 14 IB

> > ' I i I t 1 I

A Portion of NEWTONS MAP"™* BLACK HILLS.

Figure 1.

Distribution \m> Structure of the Rocks.

As shown by the accompanying map (fig. I I, copied from Newton's report,
the pre-Cambrian rocks are divided into an eastern or slate and a western or
schist area. Within the schist area arc located several detached masses of

inite, one of considerable size, the highest peak of which is the culminating
point of the hills. The slates and schists arc described by Newton as verti-
cal and as having in general a strike approximately north and Bouth, or a
little wesl of north and south of east, with wide local variation. Although
Newton and Jenney looked for proof of discordance between their slate and
schisl series, they found no positive evidence of it, although at one obscure
locality Jenney thought he saw such indications.* No evidence that the
Bchisl or slate is folded was found, and it was thought their combined thick-
ness is very great, being represented by the surface exposure of the pre-
Cambrian core in an cast and west direction. The following paragraph is
from Newton :

lination brought to light no evidence of the duplication of any part- of
the Archean rock Bystem. If the 3lates or the schists were folded upon themselves
and afterwards worn away, so a- to leave two or more parallel outcrops of the same
beds, tic folding must bave 1 n confined to the homogeneous soft beds : and the pre-
sumption is Unit no such folding took place within the area exposed in the hills.
The \\ bole system of vertical beds, with a width of about twenty-live miles, i- believed
to retain it- original .'-elation of parts. It. has not. of course, it- orignal position, for
the same great process of change which has produced it- metamorphic structure has
turned it bodily on edge and either broken away or eroded away in upward continu-
ation : hut it i< probable that the system prevents tic clays and -hah- ami sandstones
from which it wa- produced by metamorphism in the same order in which they were
originally depo

The enormous thickness of sediments which this explanation requires was
realized bj Newton and ( rilbert, and was evidently regarded as a fact against
it- corrects -- No subsequent writer has attempted to re-examine (he evi-
dence upon which this great thickness for the pre-Cambrian rocks is based.
My study of the -late area agrees with Newton's observations that the
rock series ha- a cleavage which is practically vertical. Howcver.it was
ascertained that this parting i- in the nature of Blaty cleavage rather than
' trui' bedding. The fact that there are partings in two directions in certain
localities ha- been noted by both Crosby and Carpenter, bul particularly
the latter, who interpreted these to mean that the rocks had been subjected

to pressure in two directions : and in some places this explanation is the true

one.

Dakota, p

SLATY CLEAVAGE AND ELONGATED PEBBLES.

■Jo-

in the eastern slates is :i broad belt of conglomerate which was discovered
by Carpenter. A careful study of its exposures shows that the rows of
pebbles and bowlders have uo regular relation whatever to the slaty cleavage
running across them at various angles at different localities. The pebbles
and bowlders themselves are, however, elongated parallel to the cleavage
(fig. 2). These phenomena were observed many times at points far apart.
Also, bedding lamination, cutting the slaty cleavage, was found at many
points, aud in places the former is directly transverse to the latter. It
follows that the breadth of the slates as measured across their outcrop gives
no indication of their true thickness. The fact that certain belts of

Figure 2. — Bands of Conglomerate cutting Slaty Cleavage.
The elongation of the pebbles is parallel to the cleavage.

quartzites aud schists, haviug a general resemblauce, are found parallel to
each other would seem to indicate that such belts are repeated by folding.
Within the brief time given to field study no attempt was made to work out
the structure of the pre-Cambrian rocks in detail ; but clearly the whole
question of their real thickness is thrown open. That slaty cleavage was
mistaken for bedding by Newton is not strange, for that schistose structure
and slaty cleavage not only may be, but very often are, completely independ-
ent of bedding was, a dozen years ago, by no means so widely recognized as at
present.

Starting with Newton's ideas of the distribution and lithological distinc-
tions between the slates and schists, I began my study, believing that in all
probability the schists and granite represent an older formation than the
slates. Also, I supposed the two formations were either unconformable, or, if
in apparent conformity, were so by subsequent squeezing.

The area about Deadwood, in the northern hills, is entirely within the
slate area as mapped by Newton (fig. 1). To my surprise, upon nearing
that place, the rocks became more aud more crystalline, and for a consider-
able area about this mining town the rocks are crystalline schists. Passing

208 < . r. v.vx ftisf: — pre-cambrian of the black hills.

to the southward, slates are again found. Rochford is about one-third the
way south in the pre-Cambrian core and near the line dividing the two sup-
posed series. From this place excursions were made both east and west, the
first of which ought to traverse the slate area and the second the schist area.
So far a> could be made out, the rocks were not more crystalline west than
east. Passing southward from Rochford toward Hill City, the course of
travel was such that it crossed and recrossed Newton's boundary between
the slate and schist series. While to the south the rocks were found to
become more crystalline, no difference in this respect was observed east and
west. The slate area was mapped as coming directly in contact with the
granite in the southeastern part of the pre-Cambrian area. North of the
granites were found, for some distance, as thoroughly crystalline schists as
anywhere iu the Hills, the rocks becoming less crystalline, however, toward
the north. .V journey was made around the granitic area, and all the way
crystalline schists were found surrounding it. These schists everywhere
strike parallel to and dip at a high angle away from the granitic core. To
a certain extent these relations were noted by Newton, and his observations
are verified by Crosby, although neither reached the above generalization.
They are of such interest that Newton's words are quoted.* He says :

•■ West el' Harney the strike "f the rocks is from north and south to northwest and
southeast, and we find the inclosed granite masses running in the same manner.
Southward, on French creek at and above tie' stockade, the strike of the schists is
changed, and with them the inclosed granite ridges run nearly east ami west. South-
west of the stockade, in Custer park, the schists and granite run north and south,

and this strike is exchanged in tl astern pari of the park region for an east and

!, which bends around on the easl side of Harney, becoming the customary trend'

toward the north and north west."

******
" Tin: dip of the schists is usually very high and often vertical, though occasionally

by local variation it becomes quite low. In several places a differen< f dip was

noticed between the schistose rock- on the west and the Blates on the northeast side
of Harney peak, the former being toward the wesl and the latter toward the east,
but the number of observed point- oi variation was not sufficient to warrant the
temenl that this difference is a p M feature of the relation of the two series

<,f rock-. Tin-re i- found a change corresponding to the change in strike

already noticed on French creek, and the dip becomes slightly southward from the
vertical. On the headwaters of Red Canon creek it is 70° to vo south; on lower
French cr< outh."

Neither New ton nor < Irosby -ay anything about the relative strike of tin'
Blaty and Bchistose rocks north of the granite, although adjacent to it is
drawn the line dividing the two supposed series. < >ur examination showed
here, as elsewhere, that the schists strike parallel to the granite -i. e., in an

of Pa

CONCENTRIC STRUCTURE OF THE SCHISTS. 209

east and west direction. The change in the strike of the schist is not abrupt,

as might be supposed from the above, hut in turning from one cardinal
direction to the next all intermediate positions of it are found. The schi.-ts
then form a broad concentric shell about the granite area. In going north
the schistose structure parallel to the granite becomes less and less prominent.
A lew miles away from it the rocks are found to have a structure parallel
to the granite and also one parallel to the slaty rocks to the north, the two
being nearly at right angles to each other. Going still farther away from
the granite, the slaty structure becomes more and more prominent, until
finally the schistose structure parallel to the granite has wholly disappeared.
In this pas-age the rocks have lithologicallv changed their character. Ad-
jacent to the granites they are completely crystalline. They become grad-
ually less and less crystalline as this rock becomes more remote, until they
merge into the unmistakable fragmental slates to the north, gaining the
north and south slaty cleavage in proportion as the schistose structure is lost.*

The significance of the foregoing remarkable structural relations do not
seem to have struck either Newton or Crosby. It would seem that it is fatal
to the idea that the schistose structure represents bedding. It is, however,
at once explained by supposing the granite to be igneous. The parting and
crystalline character would then be regarded as due to contact action and
dynamic metamorphism. This suggested origin of the granite will be dis-
cussed later.

We now have reached some conclusions as to the crystalline schists which
differ from Newton's. Instead of being in a definitely defined area in the
southwestern part of the pre-Cambrian core, they are in two areas, one about
the granites to the south, and the other about the eruptives to the north.
Nowhere was found a sharp boundary line between the schists and the slates.
The evidence which Newton gave for the existence of two series he states to
be mainly lithological ; also he says that " The line of separation between
them can be only imperfectly indicated. Its trend, so far as could be ascer-
tained, is a little west of north. "f The difficulty in the location of this line
is a direct sequence of the fact that the slates grade into the schists. Mr.
Caswell, who did the microscopic work for Newton, clearly appreciated that
in mineral composition these two classes are essentially alike. On this point
Newton says : J

•• .Mr. Caswell's examinations show that the same minerals constitute the typical
rocks of both series, only in the schists they are more coarsely crystallized, so that
the lithological contrast seems to depend more on the degree or character of their
metamorphism than on any difference in chemical constitution/'

* It would be of interest to ascertain the relations of the strikes and dips of the schists of the
extreme southern part of the pre-Cambrian area both to the smaller masses of granite and to the
Harney i>eak mass.

(■Geology of the Black Hills of Dakota, p. 54.

| [bid,, p. 62.

210 C. R. VAN 1 1 1 s J : — PRE-CAMBRIAN OF THE BLACK BILLS.

The only mineralogies] difference mentioned between the two series is the
ater abundance of garnet and mica in the schists than in the slates, and
the rare occurrence of staurolite in the latter.* It so happens that the best
occurrence of coarse garnetiferous and staurolitic mica-schists which I know
are uorth of the main mass of granite — i. e., in the slate area as mapped by
Newton. In .-hurt, do evidence was found that there are two distinct pre
( lambrian sn-ics in the Black Hills. r However, from my brief examination,
I would not venture to assert that there are not two or nioie, for 1 realize
that the true structure of such ancient crystalline and semi-crystalline rocks
can only he certainly determined, if at all, by the most detailed study : hut it
appears t" he a safe conclusion that the separation of these rocks into two
series upon Newton's basis and with his distribution is not warranted by the
tact- now at our disposal.

Origin of the Granite.

We now coiiie to a question upon which the various writers on the Black
Hills hold different opinions.

. Newton maps a considerable area as solid granite. South of this are
found upon his map other detached areas of the same rock. It does not
appear, however, from his descriptions that he considers these areas wholly
of granite, hut that it i- predominant. This mapping has been criticised by
Crosby and Carpenter upon the ground that within these areas is found a
quantity of crystalline schists. This is unquestionably true, hut the fact
remains that about Harney peak is a verv considerable area which is practi-
cally solid granite, although within two miles from this point are found here
ami there patches of schist. The relation- a- I saw them are these: In
passing away from the central granitic area the schists appear included by
the granite. They become more abundant in receding from the central core,
until they are finally predominant The granite is then contained in the
schists in a series of veins or dikes, which often run in parallel directions.
For instance, near Custer City fifteen parallel ridges of granite were counted
from one point within a short distance. As the granite core becomes more
distant tin- ridges become less ami less prominent and of smaller size, and
finally disappear. While no such ruck is mentioned by Newton as occurring

in the slate area -th of the granites, ridges of it are found here as elsewh< rt

about the main area.

Newton, in discussing the origin of the granite, states thai it often contains
irregular fragments of schist -some of small, 3ome of great Bize. He finds

i I

• ■- in the pre Cambrian an urn-. I to Pro

15 him if ii" had evei irdance between

• had not, and thai - itimes he doubled whethei there

RELATIONS OF SCHIST AND GRANITE. 211

the bounding lines between the schist and granite to be always sharp. His
conclusion is that the relations are what they would he if the granite were
intrusive, and the schist areas fragments caught in it. This conclusion for
a part of the granite was first questioned, so far as I know, by Emmons, who
-peaks of one of the ridges as being pegmatitic. Carpenter regards all the
granite as metamorphic ; Crosby considers it all pegmatitic.

It seems to me, however, that neither Crosby's nor Carpenter's theory of
the origin of the granite sufficiently explains the facts upon which Newton
based his opinion that it is in the main eruptive. Also, it will be noted that
all my own observations as to the relations of the granite and schists bear
toward an eruptive origin for it. The distribution of the two rocks is ex-
actly wdiat we would expect if a great mass of molten material had been
forced up from deep within the earth, thrusting aside the slates, breaking
and penetrating them by apophyses. Further, as has been seen, the fact
that the schists strike everywhere parallel to the granite core and dip away
from it is just what would happen if this were the case. Later, when the
lithological character of the schists are considered, it will be seen that they
also furnish important corroborative evidence of this conclusion. The gran-
ite core, the adjacent great granite masses, and the large granite ridges are
in general of much the same character, except that there is a variation in
coarseness of grain. The small ridges or veins remote from the central
masses become at times more quartzose than the average rock, and in a few
cases have to some extent a vein structure. It is quite conceivable, indeed
probable, that locally subsequent infiltration has played a relatively impor-
tant part, or even that some of the veins are wholly pegmatitic ; and this is
particularly likely to be the case with those which have been most closely
examined — i. e., those bearing a small percentage of cassiterite. How a part
of the granite may be pegmatitic when its great mass is eruptive is easier
to understand than upon the hypothesis that, with no known exceptional
causes, immense masses of metamorphic or pegmatitic granite have formed
within the slates and schists, and yet everywhere are sharply separated from
them .

A second crystalline schist area has been noted in the northern hills.
Here it will be remembered are abundantly found comparatively late erup-
tives — rhyolites, trachytes, etc. The quantity of the dikes of these materials
over considerable areas is so great as to compose a large part, at least a
third, of the total mass of the rock. Also, contained in these later volcanics,
have been found by Newton fragments of granite precisely like that occur-
ring to the south. The presence of crystalline schists in the northern hills
associated with these volcanics is suggestive of their origin, when taken in
connection with the fact that the schists of the south are associated with
rocks presumably eruptive. It may be conceived that these crystalline

XXVrn— Hum.. Groi,. Soc. A.m., \'<«.. 1, 1889.

212 C. R. VAN FIISE — PRE-CAMBRIAN OF THE BLACK HILLS.

schists are due to the metamorphosing effects of the modern volcanics them-
selves, or to the existence at do greal depth of a mass of granite like that al
Harney peak, as possibly indicated by the presence of fragments similar
to it iii the newer intrusives.

A.GE OF THE GR V.NITE.

The relations of the granite to the schists in the southern hills Buggesl the

■

possibility thai its intrusion attended the present Black Hills uplift. How-
ever. Newton, in discussing the age of the granite, showed that this could
not be the case. He found at the French creek section (I use bis words

that—

•A continuous sheet oi the Potsdam passes from a surface of eroded schists to a
surface of granite. There was found no intrusion of the granite along the parting
between the Potsdam and the schists, and there was found no metamorphism of the

Potsdam nt the surfai f contact with the granite. In these particulars the relations

of the granite are strongly contrasted with those of the trachyte of the Hills.
Wherever the trachyte appears beneath the Potsdam the latter is uplifted as though
by the insertion of the trachyte between it and the Archean, and its lowest beds arc
at tic- Bame time metamorphosed as though by the heat of the molten intrusion. The
fact tliat tlio -Tanitc did not at this locality affect the- form and constitution <>t' the

D *■

•dam strata in a manner similar to the trachyti i well accord with the idea

that it was introduced under similar conditions and during the sane geological
period."

Also, he discovered feldspathic debris, which apparently came from the
granite, in the basal conglomerate of the Potsdam sandstone. Prof — r
Headden mentioned similar phenomena in the vicinity of Hay ward, on Battle
creek. He kindly undertook to re-examine the locality for me, and from
his account the following is taken : At the first exposure below Hayward,
( lambrian rocks are found to rest upon schists and " granite lenses or dik< s."
Ajb to the next exposure below, he Bays thai there can be no question thai
the Potsdam is unconformable to the schist nor that it rests upon the granite,
" for here a large mass of granite is covered for perhaps more than a hun-
dred feel by the conglomerate, and the same i< to be seen in several pla
on a .-mailer scale." Further, Professor Headden finds in the Potsdam con-
glomerate above Hayward, besides quartz, mica, and feldspar, rather abun-
dant crystals of tourmaline. Since no crystals of this mineral, except of
minute size, have been found anywhere but in the granite, this is additional
proof thai this rock has furnished detritus for the Cambrian basal
conglomerate.
The foregoing evidence is conclusive aa to the pre-Cambrian age of the
anite. The zone of schists about it was then developed and deeply eroded
re the I" ginning of Paleozoic time.

Permanency op Clastic Characters in Rocks.

The late Professor Irving, in the later years of his life, and I, as his assistant,
gave a good deal of time to investigating the permanency of the evidence of
clastic origin in rocks. It has been found that vitreous quartzites, for in-
stance, which formerly were regarded as metamorphic in the old sense, show
their fragmental character in the main as well as the day they were deposited.
About one hundred localities, the most of them of pre-Cambrian age, are
mentioned in Bulletin No. 8 of the U. S. Geological Survey, in which the
induration of quartzites was produced by a process of enlargement of old
quartz particles or else the deposition of new quartz between the grains
rather than a destruction of the original fragments. This list could at the
present time be greatly extended, and would include the larger quantity of
the Potsdam and post-Potsdam quartzites west of the Appalachian and east
of the Sierras, as well as most of those which have been designated as be-
longing to the Huronian. So far as our experience has extended, practically
all quartzites properly so called, of whatever age, thus reveal their fragmental
character, except when they have been subjected to great dynamic action.
It has been also found that feldspar, both monoclinic and triclinic, and horn-
blende* have the same power of renewed growth in fragmental rocks ex-
hibited by quartz grains. These phenomena have been observed both in
Keweeuawan and Huronian rocks. While locally important, enlargements
of this sort do not approach in their wide extension to that of quartz grains.

It has been found that pressure alone, or, in other words, the weight of
any ordinary amount of superincumbent rock, has been wholly unable to
obliterate in the slighest degree the evidence of fragmental characters in
quartzites. For instance, a vitreous quartzite is found at the base of the
Peuokee series of Wisconsin. Above it is the whole thickness of the Peno-
kee series, some 12,000 feet, and over this the great Keweenawan series,
estimated by Irving to be 50,000 feet thick at the Montreal river, f It is
possible, and indeed probable, that the great synclinal movement which
formed the Lake Superior basin and exposed this vast thickness of rocks
began before the end of Keweenawan time. This being the case, these
quartzites cannot be asserted to have received the entire pressure of what
now appears to be the superincumbent mass of rock, but they must have
been buried many thousands of feet below the surface. However, the grains
of quartz now betray no evidence whatever of this. The particles are not
even arranged with their longer axes in a common direction. A quartzite

* Enlargements of Feldspar Fragments in Certain Keweenawan Sandstones; C. R. Van Hise : U.
S. Geol. Survey, Bulletin No. 8, 1884, Part II, pp. 41-47. Enlargements of Hornblende Fragments;
C. R. Van Hise: Am. Jour. Sri., 3d Ser., Vol. XXX, 1885, pp. 231-235.

fThe Copper-Bearing Rocks of Lake Superior, R. D. Irving, Monograph V, U. S. Geol. Survey,
1883, p. 230.

(213)

'-Ml U. i;. VAN H.1SE — I'KI.-i A.MBRIAS <»l THE BLACK HILLS.

ut' ih«- same character is at the base of the Wasatch series. This is a scarcely
less notable example, its lower parts resting under 30,000 feel of conformable
sediments.* Peldspathic detritus, while also exhibiting greal permanence
when not subject to powerful dynamic action, is not bo refractory as quartz,
[n the "slate conglomerates " of Logan and Murray on the north shore of
Lake Huron -a part of the "original Huronian " — the abundant feldspathic
debris ordinarily shows its orignal well-rounded forms. In the Penokee
series, just referred to, is a belt of mica-slates and mica-schists. These vary into
quartzose phases at various points, which show that they, like the quartzites,
are unmistakably offragmental origin. The feldspar has, however, locally
in large measure decomposed into quartz and mica, and in the few places
where it has been the predominant or sole mineral the decomposing processes
have bet n sufficient to obliterate the evidence of the original clastic char-
acter of the rock.i But, upon the whole, the permanency of fragmental
characters in rocks when simply upturned, nol folded, however old they may
be or however deep they may be buried, is astonishingly great.

But the moment actual movement begins within a rock, evidence of frag-
mental origin is rapidly destroyed. For instance, the great mass of the
Devil's lake quartzites of central Wisconsin exhibit- perfectly, under the
microscope, its fragmental character, but alone- certain narrow zones slipping
action has taken place; the grains have here Keen elongated in a common
direction, and it is hard to find the original clastic <-<>vc< if they vet exist.
Movement within the mass of the rock has obliterated the evidence of its
fragmental origin. Of course this idea of obliteration of clastic character-
istics by rock movement is as old a- Dana's theory of metamorphism. I
wi8h, however, to emphasize their permanency when movement has not oc-
curred, although the rock may now be completely vitreous, crystalline, of
great age, and may have been subjected to enormous pressure.

In the Black Hills dynamic action has extensively occurred. Crystalline
schists have been formed from unmistakable fragmental rocks. It is the
aim of the following pages to determine to .-nine extent the actual meaning
of i he general word " metamorphism " as applied to these rocks ; in other words,
to trace out as far as practicable the mineralogical changes which they have
undergone.

LlTHOLI IGICAL I ►iVISK »NS.

Lithologically the rocks of the hills are granite, ancient modified basic
eruptives, later eruptives, slates, quartzites and conglomerates, crystalline
mica-schists and mica gneisses, and ferruginous quartz.

I leth Parallel, Vol. I Bj me ma tic Iokj

Kins

R. \ in Hi-.- Am I. XXXI, 1880, pp

CONGLOMERATES METAMORPHOSED TO GNEISS. "215

Resting unconforniably upon the Black Hills slates and schists is the
Potsdam sandstone, which is locally a quartzite. The induration of this
rock has been found by Crosby to be due to the deposition of interstitial
silica. He does not find, however, in general that it has coordinated itself
with the original grains. My own sections, upon the contrary, show this
to be the case in the quartzites collected by us.

The Conglomerates and Quartzites. — No microscopic study has heretofore
been made of the character of the changes which the various minerals have
undergone in the quartzites, conglomerates, slates, and schists of the pre-
Cambrian area, although Caswell gives their mineralogical composition.*
In tracing out the series of changes I begiu with those rocks which are
nearest to their original condition, the quartzites and conglomerates aloug
Box Elder creek, in the northeastern portion of the pre-Cambrian area.

This conglomerate area has been mentioned by both Carpenter and
Crosby. It extends several miles along the creek, and has a very con-
siderable breadth. The conglomeratic bands alternate with those which are
non-conglomeratic. The bowlders, oftentimes more than a foot in length,
are at times very abundant. They vary from this magnitude to those which
are so small as to be lost in the matrix. This conglomerate has been sub-
jected to powerful dynamic action. This is evident from the fact that the
pebbles and bowlders are elongated in a common direction, in some cases
the longer diameters being three times as great as the other dimensions.
These elongated pebbles often, instead of having roundish terminations, end
in sharp points. Also, in many cases, the pressure has been so intense as to
merge the pebbles into each other. In certain places the process has gone
so far as to almost wholly destroy the pebbles, it being only possible to dis-
cover them upon a polished surface transverse to the plane of schistosity.
Cleaved parallel to the foliation or broken, these conglomerates appear to
be but a coarse schist. The pebbles and matrix are practically one. This
extreme alteration is most frequent with the finely conglomeratic phases.
These betray no evidence of their fragmental origin, and taken by themselves
would be regarded as ordinary crystalline schists. Some of them have all
the characteristics of a coarse foliated gneiss. The associated conglomerates
only indicate that these rocks were originally clastic.

The more purely quartzitic bands do not macroscopic-ally so plainly show
the action of the forces to which they have been subject. Crosby and
Carpenter both noted the elongation of the pebbles of this conglomerate
but they agree in the statement that the grains themselves have not
suffered by the deforming action. They explain the present elongated
nature of the pebbles by supposing the grains to have slipped over each
other. These statements must have been wholly based upon the maero-

* Geology of the Black Hills of Dakota, pp. 471-ls:i.

216 V. R. VAN HISE — I * 1 ; l .-« \Mi;i;i.\N OF THE BLACK HILLS.

Bcopic appearances, for when thin sections are examined, a glance shows
that their individual grains have Buffered deformation, thus accounting for
that exhibited by 1 1 1 « - pebbles themselves. It is probable thai slipping action
i- also a partial cause.

In the purer quartzites, quartz is almosl the sole original < stituent. The

grains are usually simple : they have not been well ass irted, varying from
those which are of rather small size to those in which the term " pebble"
might be applied. They are now usually quite angular; yet in many of
them, but byno'means in all, the evidence of their fragmental origin is
indicated by a film of inclusions about their cores. The angularity of the
grains is in part due to the secondary growths, but also it is in part due to
the mechanical action to which they have been Bubject. They generally
lie with tlu-ir longer axes in a common direction, and in many case- are
unnaturally long for ordinary erosion particles. In many of the sections is
included quite a quantity of black material, mostly oxide of iron. This not
only occurs between the fragmental grains, but is also found between the
Cores and the enlargements, and, what is more important, in parallel lines
within the cores of quartz themselves I fig. 3 . These lines are almosl univer-

Fic

• ii broken perpendicular to their greatest length — i. c, in the lines

,- the im w nli ii "ii oxide.

sally at considerable angles to the greater dimensions of the grains that is
divergent from the direction of schistosity : also each -rain of quartz, instead
of extinguishing simultaneously over its whole area, extinguishes with nynute
differences of orientation, the maximum variation in a single -rain ranging
from one to Beveral degrees, and in Borne cases reaching ten or fifteen
This black mat. rial, in the enlargements of the old grains and in
the newly crystallized interstitial quartz, is plainly a secondary infiltration
p roil i n i ; I ii 1 1 the material included in the original grains transverse to their
elongation is \\k<- this and must l>" believed to have been introduced at the
same time. In Bom< cases large grains have been fractured bo as to produce

STAGES [N THE METAMORPHISM OF QtfARTZITE.

217

cracks of such magnitude that not only black ferrite but finely crystalline

quartz has been deposited between the parts, thus recementing them. In
other cases, instead of ferrite, are found rows of minute inclusions, which are
gas or liquid filled, running in parallel lines directly across the section,
transverse to the longer axes of the quartz grains (fig. 4). In other cases

Figure 4. — Part of a thin section of quartz-schist.
Showing liquid and gas filled cavities of a secondary nature.

the disintegration of the quartz particles has gone farther. An individual,
instead of extinguishing upon the whole as a unit, is now composed of
individuals which extinguish more or less independently (fig. 5 ; figs. 1 and
2, plate 4), although the positions of extinction are not far from each other,

Figure 5. — Thin section ofquartz-schir.
Showing the manner in which a large fragment of quartz is broken down by dynamic action.

except the grain has been wholly destroyed. When the disintegration of
the quartz has proceeded thus far, it often happens that two adjacent frag-
ments have merged together in part, so that it is impossible to determine
exactly the line of separation between the two. It is not ordinarily the case
that all of the grains of quartz are wholly destroyed, nor does it often happen
that all of them are practically intact. Every grade of variation from one
extreme to the other is sometimes found within a single section, and the more

218 c. i;. van 1 1 1 - 1 : — pre-cambrian of tin: black hills.

Bchistose phases of the quartzites differ from the leasl schistose phases in the
degree to which this process has been carried out.

All the foregoing facts are explained if it be assumed thai these rocks
have been subjecl i" so greal :i pressure thai movemenl has occurred within
them, elongating :ill the ^mins, destroying the perfection of the orienta-
tion in the particles or actually breaking them down altogether. Their
elongation transverse t<> fracture and in the lines of pressure, with the intro-
duction of inclusions along the cracks, are just the phenomena which would
l.e expected from tin- well-known mechanical experiments on minerals and
rucks by Daubree and ( >. Lehmann. I f there was no macroscopic evidence
that these quartzites and conglomerates had been subjecl to powerful
mechanical action, the microscopic evidence would be conclusive upon this
point.

The presence of parallel line- of inclusions, both solid and fluid, running
continuously acn tions is a matter of some interest (figs. 3 and I I.

That the rock.- showing this are clastic and the inclusions secondary in the
Black Hills is indisputable. .Mechanical action has cracked the grains in
parallel planes. These cracks have become filled with liquid. Later, by
the deposition of quartz, they have again become cemented and retain at times
numerous liquid inclusions. Cohen,* in his memoir upon the rocks of the
Oben Weilerthal, argues thai a certain quartz-schist is noi of clastic origin.
He brings as proof againsl this the presence of a greal number of pores

which are liquid filled, arranged in straight lines running from ■ -rain to

another. It is evidenl thai this appearauce has not the force which he as-
signs to it. At various times the presence of liquid filled cavities has been
taken as indicating the origin ol the quartz in which they were contained,
•■line maintaining thai such quartz cannol be igneous, bul must be of

metamorphic origin or formed by aqueo-ig us fusion. It is evident. Bince

such inclusions may be Be< lary, thai this phenomenon cannot be used to

explain the origin of a quartz.

The pebbles and bowlders of the conglomerates are usually either simple

or complex fragments of white quartz, which could have 1 q derived from

vein- or from a coarse granitic rock. Some of the quartz pebbles, however.
both in hand specimens and under the microscope, appear themselves to be
offragmental origin. This clastic appearance, if noi deceptive, would indi-
cate that there weir breaks in the deposition of the series and that an earlier
formation yielded detritus to a later, or else thai before these ancienl crystal-
line -late- and quartzites were deposited there existed other fragmental Beries
from which the\ obtained a portion of their detritus. Crosby and Carpenter
speak of the materials of the conglomerates as having been derived from t he
crystalline Bchists and granites to the southwesl ; upon what evidence, how-

llungi

ii in iiiK'-n. Band 1 1 1 188

STAGES IN THE METAMOE.PHISM OF QUARTZITE. 210

ever, does not appear. In no ease have I been able to find a truly granitic
pebble in the conglomerates, although the presence of feldspar, both ortho-
clase and plagioclase, in the quartzites aud conglomerates indicates that they
have probably been derived from some such rock as gneiss or granite. The
identification of the source of detritus is in general a very difficult thing to
do, and that in this case the material was from the particular granite and
schists now exposed in the Black Hills seems to have been assumed without
proof.

The feldspar of the quartzites and conglomerates has usually decomposed
to such an extent as to have lost its original rounded character. The re-
sultant products are muscovite, biotite, and less frequently kaolin, accom-
panied by a simultaneous separation of quartz. Generally the decompo-
sition has taken place to the greatest extent upon the exterior of the grains,
but affects them, more or less, quite to their interiors. In some sections all
stages of the change are seen, from that in which the mica forms a circle of
folia about and penetrating a feldspathic grain to that in which nothing
remains of it.

The interstitial material in the quartzites and conglomerates is chiefly
finely crystalline quartz which has been deposited as independent particles.
The induration of the rocks is then due both to the enlargement of the old
grains and to the deposition of new quartz. Pressure also may have had its
influence. The total amount of infiltrated silica is very considerable, although
the fragmental grains are of various sizes, fit closely, and consequently leave
an unusually small amount of interstitial space. This amount of deposited
quartz is increased by numerous quartz veins.

The fact that iron oxide has oftentimes been a subordinate filling material
makes it frequently easy to determine just what part of the quartz is an
original detrital material and what a secondary deposition, the former ex-
cluding and the latter including the ferrite. Accompanying the interstitial
quartz and iron oxide is a greater or less quantity of muscovite or sericite.
or both. The quantity becomes so great in certain cases that the rocks could
well be called a muscovitic or sericitic quartzite, while it occasionally passes
over into a muscovite-slate, or sericite-slate, or schist of the same kind. Other
minerals, such as iron and other carbonates, and tourmaline, are present as
infrequent additional accessories.

The micaceous slates associated with the quartzites and conglomerates
differ from them only in that the amount of feldspar in the original detritus
has been greater and the particles of smaller size. The decomposition of
this mineral has produced both biotite aud muscovite abundantly and the
luck has passed over into a slate. The nature of this process will appear
later in more detail.

The quartzites and conglomerates above described differ profoundly from

XXIX— Bull. Geol. Sue. Am.. Vol. l, 1889.

220 C. R. VAN RISE — PRE-CAMBRIAN OF THE BLACK HILLS.

the Cambrian quartzite mentioned and other quartzitea in which the out-
lines of the original grains have uol been modified since deposition. This
difference is plainly due to the powerful dynamic action to which they have
been subject. In their transformation no evidence has been discovered
to -how whether any of the material has ever been highly heated, as
is usually assumed to be the ease in 'metamorphosed rocks. Siliceous in-
duration is known frequently to occur as a surface phenomenon. So far as
can be seen, the causes which have obliterated to a greater or less degree
the evidence of clastic characters are purely chemical and mechanical. It
is easy to see that, in the non-conglomeratic phases of rock, it' the squeezing
had been somewhat more intense, the proof of fragmental origin in them
would have been wholly obliterated. It is to be noted in this connection
thai the coarse conglomerates which have an unusually crystalline matrix
show, macroscopically, mosl strongly the deformation effect- and merging
together of the pehhles.

The silica-bearing solutions which traversed the Black Sills quartzites
and conglomerates wen- not only capable of depositing, but, as shown, did
actually deposit quartz, thus preventing these rocks from becoming pulver-
ized during the movements through which they passed. When cracks
formed of sufficient size, either in the rock as a whole or in the individual
grains, they were at that time or subsequently cemented with new quartz.
At favorable moments the particles began growing, each coordinating the
new quartz to itself. Also in the interspaces independent quartz was
deposited. Consequently, while the mosl Bchistose of these rocks have now
become composed of angular interlocking particle- of quartz, showing little
or DO evidence of clastic character, they are nut less Strong than vitreous
quartzites which have become completely indurated without motion by the
growth- of the old rounded -rain- until the enlargements met and inter-
locked.

The solution of silica in ruck- -given the element of time —with great
readiness, and its deposition as quartz in the interspaces of locks in vast
quantities, seem at first almost incredible; yet no one who ha- examined
microscopically the quartzites of our continent can doubt for a moment that
Buch is the fact. For the most part in ordinary quartzites the original

iin- lie.-,.-, round and perfect a- the day in which they were deposited in
-a ii< I -tune-. Suppose a sandstone to he composed of spherical grains of quartz
of equal size, the panicle- being packed as closely a- i- geometrically pos-
sible, the amount of new quartz required to completely till the interspa
would he twenty-six one hundredth- I,'. S. Woodward I of the total -pae,-. mi-
ii lore than one-third of that occupied by the original grains. A- a matter of
tact, under natural conditions this amount has never heeii deposited, because
i he grains of sandstones are not spherical nor of equal Bize; because the inter-

THE SILICIFICATION AM) INDURATION OF ROCKS. "221

spaces to some small degree are filled with other materials ; and because it
cannot be asserted that they are ever perfectly filled, although apparently
this is often the case. This very large theoretical amount of silica is ap-
proximated in the somewhat rare, evenly granular, pure, vitreous quartzites.
It is certain that the amount of secondary quartz required to indurate such
vast formations as the Paleozoic and pre-Paleozoic quartzites of the west is
enormous.

The thicknesses of the Weber, Ogden, and Cambrian quartzites of the
Wasatch, using Emmons' and King's lowest estimates, aggregate 18,000
feet.* The Uinta sandstone and quartzites have an estimated thickness of
from 10,000 to 13,000 feet.f The quartzite of the Medicine Bow mountains
of Wyoming is of great, although undetermined, thickness.^ The combined
area covered by these quartzites is thousands of square miles. An exami-
nation of my collection of specimens and thin sections from all of these
regions shows that the chief cause of the induration of the rocks is interstitial
quartz, the major part of which has been added to the original clastic grains.
The quartz deposited in vein filling is as nothing compared with this.

As to the source of these vast quantities of silica, we can at present do
little more than conjecture. It seems to be taken for granted by most writers
that quartz itself is wholly insoluble within the crust of the earth ; that in
order to be dissolved the silica must be in the colloid form. These are points
upon which evidence is needed. That much silica is derived from and taken
in solution during the decomposition of silicates cannot be doubted. We
know that silica is often largely contained in the water of hot springs.§ Is
it not probable that the water deep within the crust, therefore presumably at
a relatively high temperature, carries ordinarily a considerable quantity of
silica which is ready to be deposited when favorable conditions arise? Nu-
merous experiments upon crystallization show that the presence of crystallized
nuclei in a solution is very favorable for the deposition upon them of like
material. In the quartzites we have such nuclei in the rounded grains of
sand.

In the elder Hitchcock's remarkably able studies upon the metamorphism
of rocks,|| published iu 1861, are described some extensive conglomerates
associated with and passing into crystalline schists, which are very similar
to those of the Black Hills. He had not the microscope to assist him ; yet

*United States Geological Explorations of the Fortieth Parallel, Vol. I, Systematic Geology, by
Clarence King, 1878, pp. 155-156.

t Ibid., p. 150; Geology of the Uinta mountains, .T. W. Powell, 1876, pp. 143-144.

X United States Geological Explorations of the Fortieth Parallel, Vol. II, Descriptive Geology, by
Arnold Hague and S. F. Emmons, 1S77, pp. 104-109.

2 For foreign localities, see Roth's Allegemeine und Chemische Geologie, Vol. I, 1879. For
United .states localities, see Bulletins of the U. S. Geological Survey., No. 32, Lists and Analyses of
the Mineral Springs of the United States, Albert C. Peale, and No. 47, Analyses of Waters of the
Yellowstone National Park, with an Account of the Methods of Analysis employed, Frank Austin
Gooch and James Edward Whitfield. The latter bulletin gives over forty water analyses, in all of
which silica is found. In many it constitutes twenty-five or more per cent, of the total soluble
material, while in one case it runs as high as fifty per cent.

|| Geology of Vermont, Edward Hitchcock, Vol. I, pp. 22-52.

'2-- C. R. VAN HISE — 1'KI-X AMUUIAN OF THE BLACK HILLS.

hi- field studies prove conclusively, as it seems to me, that genuine crystalline
schist < have developed from clastic rucks at Newport, Rhode Island, and
East Wallingford and Plymouth, Vermont. Not only is this true, but in
general his conceptions as to the manner in which the change occurred show
great insight. Many of his figures are almost identical in ideas with the
figures published <>t'the well-known schistose conglomerates of Norway and
Germany, more recently described.

The pebbles of the Vermont conglomerates are mainly of quartz. Hitch-
cock could not believe, as was maintained by Tyndall,* that so rigid a
substance a- quartz, however great the pressure to which it was subject, could
suffer internal movement and retain its strength. That silica is so readily
and extensively transferred in rocks he hail no means of knowing: hence
he was driven to explain the presence of the distorted quartz pebbles by
supposing that they represented residual silica from silicates. We now
that both Hitchcock and Tyndall were in part right and in part wrong.
The process of elongation of quartz is analogous to hut not like the flow of
ice in a glacier. The distortion is chiefly accomplished by fractures and
revelations, the quartz remaining rigid ami solutions being present to serve
as a carrier of silica : whereas the substance of a glacier itself is alternately
liquid and solid. It will he noted that for this metamorphism a high degree
.if heat is not requisite, as is commonly assumed. The temperature of hoi
springs is certainly sufficient, hut it is not asserted that a higher temperature
was not actually present, although it i> manifest that no such heal and
pressure obtained as would he requisite to render quartz itself in any degree
plastic. The possibilities as to the plasticity of many rock-, under ordinary
( litions as to heat, when brittle quartz is found to he capable to a certain

extent offlowage, are very suggestive.

Aiiothn- line of study presents itself in considering these squeezed con-
glomerates. I; may be assumed in general that the matrix bas been elon-
gated a- much as the pebbles. By taking many measurement-, of normal
erosion pebbles ami thus getting the ratio between their longer and .-holier
diameters, and doing like work with the pebbles of the same composition and
magnitude in conglomerates which have keen subject to dynamic action, we
would lie able to get an approximately reliable quantitative measure of the
amount that the beds have keen diminished in thickness by the mechanical
action to which they have been subject. This has not been done with the
Black Hills rocks, but it i- -ale to say the diminution in thickness of the

original bed- i- very < siderable.

Tin Mica-slates and Mica-schists.- The slates, quartzites and conglomerates
cur in a broad belt in the ceuter of the pre-Cambrian area, the conglnm-
:•• - being more largely kuown to the east. Passing north or south from this

Gl Ips, l"li W7.

STAGES IN THE METAMORPHISM OF MICA-SLATES. 223

belt, the rocks become more crystalline and grade into the schists about the
volcanics to the north and the granite of Harney peak to the south. In the
field no unmistakable fragments have been found by me in the schists
immediately adjacent either to the granite or the volcanics, although certain
obscure forms were seen which may represent what may have been fragments.
In the transition in both directions, greywacke-slates change to mica slates ;
the mica-slates to non-foliated mica-schists ; the non-foliated mica-schists into
foliated mica-schists (which are both garnetiferous and staurolitic), and even
into gneisses. This gradation is not made out in any one continuous ex-
posure, but by many sections of detached exposures, in all of which the same
phenomena are observed.

The steps in the process of transformation, as seen under the microscope,
are in many respects like those I have already described as occurring in the
upper slates of the Penokee series.* Later, Bonney f described some mica-
slates which have a similar origin. In the Black Hills, however, the result-
ing crystalline schists are coarser grained and more foliated than any of
these rocks. Also, unlike those of the Penokee area, they have been sub-
jected to powerful dynamic action, and this has had an important influence
in their development. The processes, in brief, which have changed these
once detrital quartz-feldspar rocks to thoroughly crystalline mica-schists are,
first, the alteration of the feldspar to the minerals muscovite, biotite and
quartz ; and, second, the breaking down of the larger clastic quartz individ-
uals by mechanical action. The first of these processes I have already
described in detail in the paper alluded to. By it crystalline schists are pro-
duced from feldspar detritus. These details I need not repeat ; but the de-
composition of fragmental feldspar is most beautifully shown in the Black
Hills rocks. It will suffice to say that as a result of this process an intri-
cately interlocking mass of crystalline quartz, feldspar and mica, or quartz
and mica, are produced from each of the large grains of clastic feldspar (figs.
1 and 2, plate 4). Usually many independent individuals of quartz and
mica occupy the space once taken by a single individual of feldspar. The
reticulating residual feldspar for a given fragmental grain acts as a unit,
except the process of recrystallization results in the formation of feldspar
of a different kind from the allothigenic individual. When the process is
complete, the interlocking mass consists wholly of quartz and mica. This
alteration is chemically possible because the micas, both biotite and musco-
vite, are much more basic than feldspar and the residual silica separates as
quartz. By imperceptible steps all phases of the alteration are seen, from

* Upon the Origin of the Mica-Schists and Black Mica-Slates of the Penokee-Gogebic Iron-Bear-
ing Series, C. R. Van Hise: Am. Jour. Sci., :'.<! ser., Vol. XXXI, 1886, pp, 453-459.

i i in some Results of Pressure and of the Intrusion ot Granite in Stratified Paleozoic Rocks near
Morlaix, in Brittany; < >u the Obermittweida Conglomerate, its Composition and Alteration : Notes
on a Part of the Hu'ronian ^erie* in the Neighborhood of Sudbury (Canada), by T. G. Bonney : Quart.
Jour. Geol. Soc., London, Vol. XLIV, 1888, Part I, pp. 11-19, 25-31, 32-44.

"Jl! 1 i. I;. VAN HISE — l'i;i:-< \mi:i; | an OF Till: BLACK HILLS.

those in which the feldspars arc practically unchanged or surrounded by a
mere film of biotite and muscovite to those in which, in place of a lai

■ i 11 of feldspar, is found a thoroughly interlocking mass ol muscovite,
biotite, and quartz.

One rock presents a modification of this process which is worthy of note.
Macroscopically it contain- a -nod many roundish or oval fragments of black,
aphauitic, cherty-looking material, some of them one-fourth nf an inch or
more in diameter. Under the microscope these turn out to lie feldspars
which have been cracked and impregnated through and through with the
ferrite found bo plentifully in many of the rocks. Their true nature is dis-
coverable only in those cases in which the amount of this material is smaller
than usual. Gradations are found from grains of which the character is
evident to those almost opaque from included ferrite.

The original quartz grains have generally heen elongated in a direction
parallel to the schistose structure, as in the conglomerates and quartzites
before described. In many cases ii is not possible at the present time to tell
what part of the quartz is original and what secondary; but frequently,
simultaneously with the other changes, has heen deposited abundant ferrite,
just as in the quartzites and conglomerates. When this bas occurred it
murk- off with perfect clearness the original fragmental quartz from the
ondary minerals. When the schists have become more thoroughly crys-
talline the only minerals now present which were originally deposited as
such are the cores of quartz in the larger elongated particles. In certain
cases the fragmental character of the quartz grains is not shown by such
inclusions but by minute Hakes of white mica, which are included in the
enlargements and lie in curved lines about the Cores. These are not BO con-
tinuous as the ferrite inclusions, bul arc sufficiently so to form well defined
oval-. Unlike the former, these folia are only discovered in polarized light.

( >fteii the fragmental quartz which has heen mingled with the feldspar has
been rather fine-grained. In these cases it is not at a glance distin-
guishable from newly developed quartz. In other cases the quartz particles
have been large; and here, unless the pressure has heen very great, they

ml out with rounded outlines in a thoroughly crystalline matrix (figs. I

and ■'. plate 1), However, in the most crystalline phases of the schists
immediately adjacent to the granite, the pressure has been so great that even
when the fragmental quartz was coarse the rock has now an evenly
miliar, roughly banded arrangement of mica and quartz. These rocks
are as c larselj and completely crystalline as mica schists which occur in the

indisputably fundamental gneiss The quartz and mica are concent rated

more or less iii alternate hand- and irregular area- just as in such rocks.
The mica folia average about 1'" '" in greatest length, and the quartz pai
tides, of quite uniform size, arc one-half i le-fourth as long. The only

STAGES IX THE METAMORPHISM OF THE MICA-SCHISTS. 225

thing which now shows the original position of the clastic particles of quartz
and feldspar is the relative distribution of the minerals. The areas in which
quartz is almost the sole constituent probably represent quartzose fragments
which have been broken down by dynamic action, while the areas which are
largely micaceous probably represent places once occupied by feldspar.

As we pass from the less crystalline to the more crystalline mica-schists
there is a gradual increase in the size of the secondary quartz particles. This
is just what would be expected from their manner of development. The
more plainly fragmental the rocks are, the finer crystalline is the back-
ground. Naturally when the recrystallizing forces have become greater the
particles which are autbigenic grow to a greater size, and this process being
accompanied by powerful dynamic action the large fragmental quartzes are
at the same time broken into small particles (fig. 2, plate 4). It follows
that it is entirely possible to produce from a coarse-grained quartz-feldspar
detritus a crystalline schist in which the quartzose background is composed
of grains of approximately uniform size, and which contains mica in large
flakes, scattered here and there in bands or irregular areas. That this state-
ment represents the actual facts in certain schists of the Black Hills, except
that the broken down quartz is a little coarser than the authigenic, cannot be
doubted by any one, I think, who will observe the gradual transitions in the
field and see the corresponding mineralogical changes in thin section.

In the mica-schists the two micas, muscovite and biotite, are both abun-
dant, although biotite is upon the whole rather more plentiful. Occasionally
muscovite is predominant. Frequently also chlorite in well defined leaflets
is present as a subordinate mineral. These minerals are for the most part
secondary developments. If any original mica is now present, it is in sub-
ordinate quantity. The micas are arranged to a remarkable degree with
their longer axes in a common direction parallel to the schistose structure
(fig. 2, plate 5). Sometimes, as will be seen, wThere there is a slaty cleavage
or schistose structure in two directions, the mica flakes show a peculiar
double arrangement corresponding to them (fig. 1, plate 5). The general
perfection of the linear parallel arrangement of the micas and the quartz,
the beauty of the former minerals, and the absence of all others as impor-
tant constituents combine to make these rocks the most perfect examples of
mica-schists that I have seen.

The greywackes, mica slates and mica-schists frequently become very
fine-grained and pass into aphanitic slates and schists. These, however,
need no detailed description, as they repeat with smaller particles the same
story told by the coarser-grained rocks. In certain of them, evidence of
fragmental origin is found ; in others it is wanting. These rocks appear to
have differed chiefly from the mica-slates and mica-schists in that the original
detritus was much more finely comminuted and doubtless contained a rela-

220 R. VAN RISE — Pl.T-i \Ml:l;l\\ OF THE B] VCK HILLS.

lively larger proportion of purely clayey materials. They also <•< ► 1 1 1 :i i n in
many cases a very large proportion ofpyrite mingled with theferrite. The
total of these ferriferous materials is much greater than in any of the coarser-
grained micaceous rnrk-. Newton states that the black slates contain car-
bonaceous material. It' this is 1 1 1 « - case, and I have no doubt that it is, the
pree of the large amount of iron sulphide may be explained by the

reducing action of such organic matter.

In a few cases have been found, in the less thoroughly crystalline grey-
wackes. a class of r""k in which the alteration product of the detrital feld-
Bpar i- a variety of amphibole. In (his decomposition the relations between
the feldspar and amphibole are exactly like those between the feldspar and
mica above described. The amphibolitic greywackes differ macroscopically

fr the mica sjreywackes only in that they arc greenish grey rather

than grey. I -i the possibility that the decomposition of a

quartz-feldspar fragmental rock may also under favorable circumstani
produce a hornblende-schist : but while hornblende-schists are found inti-
mately associated with the micaceous slates and schists, the connection be-
tween them and these greywackes, it' any exists, has not been worked out.

/ Mica-gneisses. — In most of the mica-schists the <• litions have been

such that the old fragmental feldspars have decomposed. In a few of them
an- found small individuals of perfectly fresh feldspar which inclose particles
<>t' secondary ferrite. From their appearance they are taken, like the mica.
to be a new crystallization. Ajb was first described by Teall,* and subs
quently by other writer.-, old feldspars have here broken down, and at the
same time new ones have formed of a different character. In a lew cat

amoug the most crystallii I these mica-schists the amount of such original

feldspar is sufficient to make the rocks a muscovite-biotite-gneiss. In their
macroscopic appearance these rocks do not differ from the mica-schists just
ilescribi I. In tbiu sections, their background, instead of consisting almost
wholly of quartz, as in the mica-schists, is of evenly granular quartz and
feldspar in approximately equal amounts. The feldspars are for the most
part perfectly fresh, and comprise orthoclase, microcline, and plagioclase.
'The latter i- twinned both according to the albite and pericline laws, both
kinds of twinning often being found in the same individual. The inter-
iking of this quartz-feldspar background is as intricate as in any ordinary
of the same di >f coarseness. Both mica- are abun

dantly present, hiotite being the more plentiful. The Kind.- are arranged
in mon direction to a considerable extent. In one case the twin

lamella; of the plagiocla erally correspond in direction to the folia of

mica and the tion of the grains of quartz. In th< of microcline

and the double twinned pla i the twin lamella; of course run in this

i il I'eall

DEVELOPMENT OF ACCESSORY MINERALS. 221

direction and also at right angles to it. Contained abundantly are very
numerous particles of iron oxide — hematite, — many of which have crystal
outlines. If it were not that this inclusion chances to be present there
would be nothing in the thin sections, so far as one can see, to show the
genesis of these rocks. When they are examined closely it is seen that
while this material is contained in the most of the feldspars, in the mica
and in the smaller particles of quartz, it is only contained in the exterior
portions of the larger particles of the latter mineral. These show round
or oval cores which are perfectly free from this inclusion. In these rocks,
as in the thoroughly crystalline mica-schists, the cores of quartz stand as
the only representatives of the original detritus. All other materials have
recrystallized. That the major part of the feldspar is really authigenic
rather than remnants of clastic particles is shown by its freshness, by its
inclusions, and by the fact that in one case its twin lamellae, probably in
obedience to pressure, uniformly follow the direction of schistosity.

Garnet, Staurolite, and Tourmaline. — In all the foregoing rocks are found
various accessory minerals, the chief of which are garnet, tourmaline, and
staurolite, although Newton says tourmaline occurs only in the granite.*
Within the quartzites, conglomerates, and greywackes these minerals are
relatively unimportant. They increase in abundance as the rocks become
more crystalline, and in some cases they become principal constituents.
Garnet is much more widespread than the other two, although the amount
of tourmaline and staurolite present is very considerable. These minerals
all have the characteristics usual when occurring in crystalline schists, and
they will therefore not be described in detail. As much has not been made
out as to their manner of growth as could be wished. There is little doubt
that they, like the mica and interstitial quartz, are secondary constituents.

The garnets usually do not reach a magnitude of more than 2'""1 in diameter,
while their average is much smaller than this. In their growth they have
shown remarkable power in excluding or absorbing other minerals. Biotite
is generally not included at all in the garnets of the coarser, although quite
often included in those of the finer grained schists and slates. Quartz is
included to a greater or less extent, and in some cases quite largely. The
frequent absence in the garnets of the black ferriferous material which is
plentiful in the remainder of the section suggests that as the garnet has
grown it has absorbed much of that material. In the cases in which the
amount of ferrite or pyrite is very great the garnet has not been able to
wholly exclude or absorb them. In many cases the inclusions within the
garnets are more abundant near their centers than in their exterior portions.
This may mean that during the first part of their growth only was the fer-
rite being abundantly deposited. Often also the inclusions are arranged in

1 reotogy of the Black Hills of Dakota, p. 70.
XXX — Bui.r,. (teoi.. Soc. Am., Vol. 1, 1889.

228 C. R. VAX ills]-; — PRE-CAMBRIAN OF THE BLACK HILLS.

parallel lines. In some cases these lines arc parallel to the schistose struc-
ture ; in others they are at an angle of about 60° to that structure, as though
the time of the growth of the mica marked a different epoch from that of
the garnet. Often the black material is arranged in such a fashion as to
show to some extent the manner of the growth of the garnets — that is,
included particles are arranged in lines which radiate from the centers.
Further, a garnet area is often subdivided by strongly marked lines of inclu-
sions, so that it has the appearance of consisting of several individuals which
have a cleavage which in each part is approximately parallel. This appar-
ent cleavage is of course not that, but is due to rows of inclusions.

The staurolite, as is characteristic with this mineral, includes alike all the
other constituents with which it comes in contact, sometimes the area which
a crystal occupies being fully one-half taken by extraneous minerals.

The tourmaline, even to a greater extent than the garnet, has shown power
to wholly exclude all other minerals. One tourmaline mica-schist is worthy
of a detailed description. This rock is a black, evenly laminated one, show-
ing large folia of mica and lustrous crystals of tourmaline; is strongly
foliated so that its cleavage surface gives back a brilliant sheen. It is finely
laminated, 'the lamina' being of slightly varying color. Altogether the rock
has the appearance of a completely crystalline hornblende-gneiss. As
examined in thin section the background appears to consist almost wholly of
quartz, although there may be more feldspar present than would bethought.
There is no decisive evidence that any of this quartz is fragmental, but
occasional grains have vague lines of inclusion in their outer parts which
may indicate that clastic cores are present. Scattered through this back-
ground in about equal quantity arc tourmaline and mica, the latter includ-
ing both muscovite and biotite. The tourmaline is almost wholly in well
defined crystals. The section is cut parallel to the schistose plane of t he
rock — i. '., parallel to the greater number of laminae of mica, — so that most
flakes are basal. The tourmaline, on the other hand, is as uniformly cut
parallel to the vertical axis. There is also a tendency for the majority of the
vertical axes i" arrange themselves in a common direction in the plane ol
schistosity, but this failsto carry with it many individuals. If pressure has
been the controlling force in the initial arrangemenl of the particles of mica
and tourmaline, these relations — i. e., the biotite basal and the tourmaline
longitudinal— are jusl what would be expected. The tourmaline is abun-
dantly included in nil the other minerals. The biotite frequently contains
black particle- of ferrite, which suggests that possibly this accessory has been
the factor which controlled the location of the folia of biotite.

Immediately adjacent to the large granite masses in the southern pari of
the hills are found certain very <• »arse muscovite-biotite gneisses which con-
tain much feldspar. These, upon the whole, are more analogous to the granite-

RESEMBLANCE OF ROCKS TO THOSE OF LAKE SUPERIOR. 229

than to the mica-schists and mica-gneisses above described. Their genesis
is uncertain. They may be merely foliated phases of the granite, or they
may be masses of the clastic rocks which were caught within the granite and
so profoundly altered as to lose all trace of their fragmental character.*

Other Crystalline Rocks. — I shall not attempt in this paper to give a
detailed description of the several other kinds of rock which occur in the
pre-Cambrian core of the Black Hills. In order to make a comprehensive
comparison with other localities, it is, however, necessary to briefly charac-
terize them.

The first in importance among these are the quartz-rocks, ferruginous
cherts and schists. The chief constituent of this class is finely but com-
pletely crystalline interlocking quartz in particles of quite uniform size. No
evidence is observed that any of them are fragmental. The chief remaining
substance is iron oxide, which occurs in the forms of limonite, hematite, and
magnetite. The only other constituent of importance is muscovite. Occa-
sionally a little biotite and iron carbonate are seen. The iron oxide is often
concentrated into layers, and thus locally makes up a considerable propor-
tion of the rock. The highly ferriferous layersare interlaminated with those
that contain much less iron oxide. These oxides usually have crystal out-
lines, and the particles are arranged in entire independence of the quartz.
The relations of the two minerals are just what they would be if the iron
oxide had wholly crystallized before the silica appeared. The quart/
phases are called " quartz-rock " inorderto separate them from the quartzites,
the latter term being restrieteil to rocks which are chiefly composed of worn
fragments of quartz. This distinction has proved to be a fundamental one
in the Lake Superior region, in which the cherts and jaspers of the iron
formation are always non-fragmental, while the quartzites are as plainly
clastic This class of rock, as observed by Newton, is then remarkably like
in mineral character to the ferruginous schists of Lake Superior, the chief
difference being that muscovite in one phase of the Black Hills rock is sub-
stituted for actinolite in the corresponding rock of Lake Superior. This
microscopic likeness is no stronger than the macroscopic resemblance.

The fact that associated with the mica-slates and mica-schists are ridges ami
large masses of coarsely crystalline, dark gray or green, massive to schistose
rocks which resemble altered greenstoues has already been mentioned.

* In connection with the foregoing upon the development of the mica slates and schists, ihe re-
markable studies of Sorby, began many years ago, should be mentioned. As early as 1863 his
microscopic studies showed that certain mica-slates are of fragmental origin. Many years later
t ls.so) he again took up the subject and presented additional evidence, not only that this is true, but
that the mica and much of the quartz in certain rather crystalline mica-schists and slates are
secondary developments. He was not able, however, with the material at his hand to work out the
manner of the genesis of these minerals, nor does theirsonrce seem to have occurred to him except
in a general way as developing from the original mud. His work in connection with this study as
to " stratification foliation " and " cleavage foliation" is too well known to need reference. See
"On the ( iriginal Nature and Subsequent Alteration of Mica-Schist," II. C. Sorby, Quart. Jour. Geol.
Vol. XIX, 1863, pp. 401-406; "On the Structure and Origin of Non-Calcareous Stratified Rocks,"
H. C. Sorby (part of Anniversary Address of the President of the Geological Society of London),
c^uart. Jour. Geol. Soc, Vol. XXXVI, 18S0, Proceedings, pp. 46-92.

230 '. I;. VAN III-I. — PRE-CAMBRIAN O] IIIK BLACK HILLS

Upon examining their sections, it turns oul that they vary in character from
a somewhat altered uumistakable diorite i" a completely crystalline horn-
blende-schist or chlorite-schist While sufficient time was not given to a study
of their field relations, no evidence was seen that any of them vary into the
mica-elates and mica-schists. They arc all regarded as ancient eruptive rocks
which have partaken of the alteration-effects of the forces that metamor-
phosed the fragmental series. This being the case, we have- within the Black
Hill- pre-Cambrian ana. schists which an- of eruptive ami of clastic origin.
In only one or two cases has a hornblende-schist been found, however, which
shows any indication of belonging to the clastic series, and in this rock a
larger araounl of biotite than hornblende i- present. The foregoing rocks,
with t: ption of that just alluded t<». are very similar !•> certain rocks

of the Lake Superior region in which Dr. George 11. Williams has carefully
traced out series running from undoubted eruptives to hornblende-schists ami
chlorite-schists My lack of material, as well as limitation in space, pre-
vents an attempt t<> do the like with the 15 lack Hills rocks. 1 [owever, it may
be said that the thin sections give a tolerably complete gradation from an
unmistakable diorite t" one in which the e i> little or no feldspar, quartz and
hornblende taking its place, and the rock becoming a crystalline hornblende-
Bchist. A further set of alterations has then seized upon certain of them bo
that their background contains, in addition to the quartz, a good deal of
call \t the same time the hornblende has passed over into chlorite or into

chlorite and epidote, the rock thus becoming a chlorite-schist or an epidotic
chlorite schist.

The granites have Keen -<> fully described by Newton and Caswell thai I
give them little -pace. Tiny are in the main coarse-graiued muscovite-
■ In- (»nly important minerals being muscovite, quartz, ami feldspar,
the latter including orthoclase, microcliue, ami plagioclase. 1 hese granites
met imes so coarse a- to give muscovite approaching that of a mer-
chantable character. These coarse phases are by mi mean- universal : and
the) pa-- into rocks which have all the characteristics of muscovite biotite-
irdi nary type. A.lso, quite frequently they vary into t<>nr
malin i-granite, this miueral l>ein_r occasionally the only imp irtanl one aside

in the quartz ami feldspar.

NaTUKI OP t >i:h.i\ \ I. BED! mi NT.

va that the detritus from which the Black llill-

leveloped was almost wholly quartz ami feldspar —

p< i hap- mingled in place- with so fiue a male rial that it could only he called

mud. n which quartz ami feldspar are largely

<-Y " . II

RELATIONS OF GRANITE ASD SCHISTS. 231

derived also yield mien abundantly. In the slates and schists of the Black
Hills these three minerals occur together, but it has been seen that much, if
not all, of the mica is authigenic. The specific gravity of quartz and feld-
spar differ but little, and it requires very favorable natural conditions to
perfectly separate these minerals. That these peculiar conditions not in-
frequently maintain for a time is shown by the interlamiuations of pure
quartzose sediments and those composed of quartz and feldspar, which is
found in many localities. Mica, while having a higher specific gravity than
quartz or feldspar, usually floats longer than particles of the same weight
of these minerals, because of its ready separation into thin flakes, and
may thus be carried to more quiescent deeper water. The conditions of
sedimentation in the Black Hills have ordinarily been such that the mica
has been separated from the quartz and feldspar, while in certain layers
represented by the quartzites the quartz has been practically freed from
other minerals. It often happens in other localities that, mingled with quartz-
feldspar detritus, is a good deal of clastic mica. The original character of
the ferruginous quartz-rocks will not be discussed. They are regarded as
chemical or organic sediments, or both combined.

Bearing of Microscopical Study upon the Origin of the Granite.

Recurring to the question of the origin of the granite, it would seem that
the foregoing microscopic study of the crystalline schists affords additional
indication that it is in the main eruptive. It will be remembered that within
the central granite mass are contained areas of the schists which appear as
though they had been caught in an eruptive rock ; that the schists form a
zone about the grauite, striking parallel with and dipping away from the
main mass ; and that radiating from the Harney peak core are numerous
dike-like ridges which become less frequent and smaller in size as it is receded
from. The lithological study shows that the schists become coarser, more
foliated, and much more crystalline adjacent to the granite, and also that
here are abundant garnet, staurolite, and tourmaline, minerals which are
very often produced by the contact of an eruptive with a sedimentary rock.
Upon the hypothesis that the granite is eruptive and the cause of the present
structure of the surrounding crystalline schists, not only the distribution of
the latter is explained, but the peculiar relations of the slates and schists
themselves. The strike of the slates is in general in a north and south di-
rection. The schistose structure parallel to and north of the grauite is trans-
verse to this ; but it has been seen that the slates grade into the schists. Be-
ginning with the slate area and passing toward the grauite area to the south,
the slaty cleavage in a north and south direction becomes less and less promi-
nent. After a time a schistose structure is found cuttiug across the slaty

232 R. VAN WISE — l»RK-CAMBRIAN "1 Till. BLACK HILLS.

:i :i direction :it righ! angles to it. As the granite is approached,
the slaty cleavage becomes fainter, the schistosity becoming gradually more
rtinct, and near the granite the cleavage is wholly replaced by the schistose
structure. The change of the original slaty cleavage to :i Bchistose structure
-: and west of the granitic area did nol result in a variation of the direc-
tion of foliation, as the new force was parallel t'> the old; l>ut Bouth of the
- on the north, the new foliation is al right angles to the older Blaty
clea

iponding to the double cleavage of the rocks uorth of the granite is a
n liar arrangement of the mica-folia as seen in thin section. In general, in
the slates and schists, the micas are arranged with their basal cleavage parallel
to ilit- slaty parting or Bchistose structure, li is to be expected when the first
of these structures yet remains and the second also has developed in a new di-
tion, that a double arrangement of the mica would be found ; and Buch is the
Dhis phenomenon is best shown in those rocks in which the two struc-
tures are about equally prominent aud at right angles to each other. Here the
larger mica Bakes are parallel to the slaty cleavage, while the smaller and more
numerous ones arc parallel to the schistose st ructure I fig. 1 . plate 5 i. This
curious arrangement corresponds with the genesis of the minerals as worked
out. The Blaty cleavage is earlier than the Bchistose structure, and folia of
mica had developed with bases parallel to the former before the latter ap-
peared. At the granitic eruption the new mica flakes arranged themselves

in corresp lence w ith the developing schistosity. It appear.- as if this later

force al a distance from the granite was nol sufficient to rotate the mica par-
ticles which had already formed. They continue. 1 to grow, and reached a
eater magnitude than the newer folia parallel to the schistose structure.
In the most crystalline schists adjacent to the granite the new force was
able to wholly obliterate all the effects of the previous slaty cleavaj

Bj NG, < 'll W \'.| \\ h l'< HI \ I l"\.

I he foregoing Btudies of the quartz-schists, mica schists and mica-guei

• srvations on the production of slaty cleavage and foliation.
\-i- well known, these structures develop as a consequence of dynamic
action. This results in the arrangemenl of the original and secondary
particles with their two greater dimensions perpendicular to the lines of pri-
mary force, producing cleavage or foliation in the planeof these dimensions.
i- a linear-parallel arrangement of the particles in this plane
ponding to the direction of a secondary force. The work is accom-
plished by the development of new minerals, which arrange themselves perforce
with i hen longer axes in the directions of least resistance ; aud, so far as the
original part mcerned, either by their rotation in the flowage of

RELATIONS OF FOLIATION AND BEDDING. _•>•>

the rock, or else by their actual deformation, which latter often occasions
fracture. The fracture of particles occurs transverse, or at a large angle to,
tin1 elongation ; for the very yielding of a grain perpendicular to the press-
ure, if carried far enough, ruptures it at various places transverse to the
direction of elongation ; i. e., approximately in the lines of pressure. All of
these points are beautifully illustrated by the phenomena which have been
described in the development of the Black Hills quartz-schists and mica-
schists from quartzose and feldspathic sandstones.

The Black Hills thus furnishes one of the best instances which have come
to my notice of the independence of slaty cleavage and schistose structure or
foliation from true bedding. A great part of the Black Hills pre-Cambrian
rocks are of clastic origin ; yet the present prominent structures have no
definite relation whatever to the original sedimentation. Not only is this
the case, but a secondary, well-developed slaty cleavage, which locally passes
into genuine schistose structure, produced at the expense of original lamina-
tion by powerful dynamic action, has for considerable areas been itself wholly
obliterated by a later force, and a new7 and more prominent foliation pro-
duced which cuts across the secondary slaty cleavage at various angles up to
perpendicularity. In rare cases a single hand specimen displays what is
taken to be the original sedimentation and both of the subsequent foliations
cutting each other nearly at right angles. Farther, associated with these
slaty and schistose rocks are basic eruptives which now have induced struct-
ures parallel to the secondary or tertiary structures of the adjacent elastics,
produced at the same time and by the same causes that the like structures
were formed in them. The principle that slaty cleavage and schistose
structure have very often no connection with original sedimentation is so
old a truth that its repetition here seems unnecessary ; yet I suspect that
geologists sometimes forget this important fact, wdiich should be constantly
borne in mind when dealing with metamorphic rocks.

The foliation of the Black Hills slates and schists through the central part
of the pre-Cambrian area varies but little in strike and dip. As has been
before said, if this were stratification it would require a thickness of sedi-
ments of from 20 to 25 miles.* Under such circumstances, when no other
structures are found, it is common to assume that such foliation is bedding,
as Newton did. This requires either a belief in great thicknesses of sedi-
ments or else closely pressed folds, the sides of which are exactly parallel
and which have been truncated in such a fortunate position as to cut none
of the folds at their turning points. I think it may be stated as a probable
general truth, in cases similar to the above, that the structures are more apt to
be secondary than original. The strike and dip of cleavage-foliation are a
function of the direction of pressure ; therefore it has a uniform dip over the

* Geology of the Black Hills of Dakota, pp. 51-52.

23-1 i i: \:W iil-i ■■— l'i:i.-< • \ M I : I : I w OF THE BLACK HILLS.

entire area in which the directi >f pressure is constant, and this oftentimes

is |arg( The folds formed at the same time cause the bedding to have wide

riations in <li|>, unless the squeezing be carried bo far as to make the sides
of the folds parallel. In thi> extreme case the cleavage-foliation and strati-
fication would ordinarily be bul slightly or nol al all discordant.

It is evident, in the Black Hills pre-Carabrian area, thai the crusl of the
earth has probably uol been compressed to Buch an extent as \\ « >n It 1 have
been the case h :i< 1 Beveral or many close parallel folds been formed bo that
the structure would represent bedding. Such a process implies great crustal
shortening. Gentle folding, and therefore a small percentage of diminution
in area, is often sufficient to thoroughly develop transverse slaty cleavaj
Mistaking cleavage-foliation for Bedimentation in areas of widely extended
parallel structure, where the theory of repeated folds is resorted to, would
lead, in most cases, to an over estimate of the amounl of the shortening of the
crusl of the earth in the supposed folding proi

( JORREI \ I [ON.

The slates and schists of the Black Hill-— that is, the great mass of the
pre < lambrian rocks ofthaf area, have been Been to be of clastic origin. This
suggests the question, <1" these rocks belong to the most ancient known com-
plex of the earth's crust ? In certain localities in the Lake Superior country
there are extensive areas of an intricate complex of granite, gneiss, :ui<l com-
pletely crystalline Bchists,* older than any rocks which have been shown to
be clastic and separated from them by a great unconformity. The larger
part of the pre-Carabrian areas of the far west are also of like character.
IV - [rving and Bonney \ have been inclined to believe that the condi-

tions which produced this wholly crystalline complex havrn.it been repeated
in the world's history. It was formerly assumed that schistose structure

a proof of sedimentary origin. It i- now generally conceded that this
structure is often found in eruptive rocks. This being the case, our own
Btudies have wholly failed to find anywhere in the northwestern country any
positive proof of clastic origin for any of these fundamental rocks, although
I incline to the belief that certain of them are profoundly modified IV.
mentals. The old ruck- of the Highlands of Scotland belong t" the class
under consideration. An exhaustive stud} of this region has been recently
made by the Geological Survey of Great Britain. Dr. Archibald Geikie,
tic 1 1 era! ofthat Survey, in a recent paper, concludes not only that

there is no trace al present of clastic character in any of these rocks, but

■■ii. in Formations, R L) Irving Seventh \nn
til of i in- ■ of London, I ' • Bonn<

lini;-, pp II" 112,

PSEUDO-CONGLOMERATES IN THE ARCHEAN. 235

that there is no reason for believing, so far as can be discovered, that any of
them have ever been clastic. Upon this point one paragraph is so decisive
that I quote it in full : *

" Nowhere, however, in the region to which I am referring has any trace of
superficial eruption yet been detected. There are no true volcanic ejections, nor any
evidence that the rocks, though certainly of eruptive origin, were ever connected with
the ordinary explosive operations of volcanic vents. Not only so, but after the most
careful search from Sutherland to Galway not a vestige have we yet found of any
unquestionable sedimentary material. There are no conglomerates, no sandstones, no
shales ; nor even any materials that might be supposed to represent these in a meta-
morphosed condition. Of the actual surface of the earth these Archean rocks afford
no recognizable trace. They obviously did not form the superficial layer themselves.
They must have lain deep under a cover of other material, under which they acquired
their crystalline structure, and by the subsequent removal of which they have been
exposed to the light."

So far as I know, the only authorities who at the present time maintain
that they have shown that any rocks apparently belonging to this funda-
mental complex f are water-deposited elastics are Dr. Alexander Wine-hell
and a few of the geologists of the Canadian Survey. Dr. Winchell argues
that certain granitic rocks iu northeastern Minnesota are conglomeratic,
and that the granite and gneiss of that region represent metamorphosed sedi-
ments. J The question immediately arises whether these rocks, if really
clastic, do not belong to a period subsequent to the fundamental complex.

I will not venture to speak on this point as to the Canadian localities, and
Dr. Winchell answers it in the negative for the region described by him. It
would, however, seem to be necessary in case an unquestionable water-
deposited detrital rock is found, apparently as a part of the fundamental
complex, to show by the most positive evidence that it can not belong to a
later series.

The presence of bowlder-like forms in various parts of the fundamental
rocks of the Lake Superior country have been somewhat widely observed by
Irving, Merriam, Bay ley, and myself. I have also seen like phenomena in
the granites of the Wasatch mountains and in those of the main Colorado
range. It has always appeared to me probable that these fragment-like
masses in the fundamental gneiss and granite in some cases represent frag-
ments which have been caught in eruptives in their passage to their present
position, and at other times represent segregations. Bearing in favor of
some such explanation is the extremely irregular shape which these inclu-

* Recent Researches into the Origin and Age of the Highlands of Scotland and the West of Ire-
land, Archibald Geikie: Nature, Vol. 40, 1889, p. 300.

f By this term I simply mean the most ancient known class of rocks, without implying anything
as to origin or expressing any opinion as to whether any portion of it represents the original crust
of the earth, or a part of that crust which for the first time has reached the surface.

{Conglomerates Enclosed in G-neissic Terranes, Alexander Winchell: Am. Geol., Vol. 111,1889,
pp. 153-165; supplement to same, ibid., pp. 256-261.

XXXI— Bdll. Gkol. Soc. Am., Voi 1, 1889.

236 C. R. V\\ HISE — PRE-CAMBRIAN OF THE BLACK HILLS

Bions often have. This facl is mentioned by Dr. Winchell in describing his
mgloraerates in gneissic terran In Professor Irving's and Mr.

Merriam's Btudiea of northeastern Minnesota, they found in Beveral local il
peculiar conglomerate-like rock- in the ancient gneisses and granites. Upon
a close i samination, the bowlder-like forma were found to be mingled with
others having the most extraordinarily irregular forms, even grading into
elongated dike-like areas. They came t<> the conclusion thai these peculiar

currences were not water-deposited conglomerates. Extremely irregular
fragments are found associated with the well rounded ones in the gneiss and
granite of the < lolorado range in the neighborhood of i fray's peak. In pla<
the fragments throw out stringers and increase in size until they assume
irregular dike-like forms or become apparenl layers interlaminated with the
coarse granitoid gneiss, jusl as in Minnesota. An examination of many
thin sections from the fragment-like areas of these ruck- shows that they arc
always completely crystalline in character. In mineral composition they
arc often like the crystalline schists which arc cut by the granites.
Frequently they differ but little from the granite in which they are con-
tained, with the exception thai some one mineral, generally the bisilicate,
is much inure abundanl in the fragment-like areas than in the ordinary
rock

It would seem that one who maintains that rucks containing well-rounded
bowlder-like forms, which sometimes are found intimately mingled with
those of extremely irregular Bhape, occurring in a completely crystalline
granular matrix arc water-deposited Bediments, is bound to explain lmw a
part of them have so perfectly retained their original forma while the others
have become bo curiously distorted. We have seen how profoundly and yel
uniformly the forces of metamorphism have acted in the Black Hills frag-
mental-; the bowlders are deformed in a common direction. This is well

known to be true of the semi-crystalline i glomerates of the Appalachian

n, already mentioned p. 221 . as described by the elder Hitchcock.;] It

■

re I li.ivc ri I red Dr \. < I i Imirable report upon tbe Rainy

inual Report of lh( - irveyof i u 1887 Pari F). The

in iiu- memoir Dr. Lawaon describee In great ■ i «- 1 *». i I

ttea iii>- ai ••■■! pseudo-conglomeratic rock a like

f which has jusl i n discussed. Hi- conclusion mewhal In the line of

baa i ii fused and the liquid

intruded the unfused stlmee t"i r. considerable distance,

on the fused and unfused aedimente occur tl" ir rocks. Ii

ii how id.' in-. -i i rocks originated, If th oglomeratii

ed and unfused materials and ""t by the metamor-

krd Hitch k, 18GI Hitchcock natiirnii-. ed with tl truo

niiv different oharaoter, found Ht
i , , Vei mi. I'll'1 in ktricea of tl

ii phyi \ In thoffl imii 'ii

and hoi nblende schist.
-, are pi obably of Pali ' olosely re-

contained fragmen italllne character.

■ . ■

-h which thej ii iv< pp. W II,

eted by Hall

MODE OF METAMORPHISM OF PEBBLES. 237

is also the case in the more crystalline parts of the Obermittweida conglom-
erate* of Germany ; and it is very marked in the scarcely less noted localities
in Norway described by Reuschf. This regularity in the form of the peb-
bles and bowlders of these undoubtedly metamorphosed conglomerates is in
strong contrast to the conglomerate-like rocks under discussion. In the
Black Hills and the other localities mentioned the metamorphism has only
gone far enough to produce a finely crystalline schistose matrix, yet in
certain cases, the pebbles lack but little of total destruction (p. 215). That
the matrix of a fragmental rock could become slowly heated to such a tem-
perature, or be subject to such other conditions as are necessary in order that
it could crystallize as a coarsely granular granitoid gneiss or granite, and
not at the same time destroy the bowlders and pebbles which it contains,
seems to me incredible. The explanation of these rocks and of the interlami-
nations of granite with slate and schist by metamorphism, implies not only
that the fragments and the bands of slate and schist have been able to resist
the forces of change during the slow processes which have been sufficient to
produce coarsely crystalline material adjacent, but that in situ they have con-
tinued to resist these forces during all the time required by the matrices to
pass once more into ordinary conditions. The processes embodied in such
" selective metamorphism " certainly need explanation. If, upon the other
hand, the fragments are regarded as caught in an eruptive rock, and the iu-
terlaminations of slate and schist with granite are due to the intrusion of
the latter, it only necessitates the capacity of the fragments and layers to
resist destruction until the heated material has solidified. As the igneous
rock has perhaps been removed from any considerable mass of fused mate-
rial, this process would be a comparatively rapid one. Yet under these
comparatively favorable circumstances, instances are too well known to need
citation of the partial or complete absorption of fragments caught in dikes
or other eruptives. If these fragment-like forms are regarded as segrega-
tions or partially absorbed fragments in intrusives, their intermingled regu-
lar and irregular forms and frequent lack of definite arrangement present
no difficulty.

From the foregoing paragraphs I would by no means be understood as
advocating the notion that all the rocks of the fundamental complex are
igneous, although in recent years it has been demonstrated that this is the
case for many of them. I merely maintain that many clastic rocks which

(p. 719). These pseudo-conglomerates and the interlamination of granite and slate (p. 562) were re-
garded as evidence that the granites and syenites of Vermont are sediments metamorphosed by
aqueo-igneous fusion. It was, however, realized that they were thorougely plastic and acted essen-
tially like eruptives. It would seem to be necessary in each individual case to show, rather than
to assume, that the material of the granites and syenites is actually derived from sedimentaries. To
extend the significance of metamorphism so as to cover crystalline rocks which have been in a
fluid condition is to make it useless for purposes of discrimination.

* Erlunterungen zur geologisehen Specialkarte des Konigreichs Sachsen — Section Elterleiu, A.
Sauer, p. 31.

t Die Fossilier fi'ihrenden Krystallinischen Schiefer von Bergen in Norwegen, H. H. Reusch :
Deutsche Aufgabe, R. Baldauf, pp. 16, 22-26, 50-56.

R. VAN HISE — PRE-( IMBRIAN OF Nil. BLACK HILLS.

have been believed in the past to be a pan of this complex have turned out
upon a closer examination to belong to a later series. I have no theory to
bring forward t" explain the origin of 1 1 1 « - fundamental complex, but Buppi
that different parts of ii will be found to have diverse histories.

This basement compli - i great in mass and so unique in character

thai Professor [rving li:i~ insisted that the term A.rchean Bhould be restrict* d
to it. and that another term Bhould be introduced to cover the clastic -■ ri< -
which are later than this and earlier than Cambrian. The great thickn
of undoubted elastics belonging here, the United States Geological Survey
has collected together under the general term "Algonkian."f This term,
thus used, certainly covers independent series of vast thicknesses separated
by great unconformities. Using ii in this sense, and restricting A.rchean as
above, the Blates and Bchists of the Black Hills of Dakota clearly belong to
the Algonkian period.

While this is undoubtedly true, it i- to I"- said that the most crystalline
mica-schists and mica-gneisses locally associated with and caught in the

nite present a suggestive resemblance on a small scale to the rocks of the
fundamental complex.} When the whole world is taken into account, ii is

-ihle. perhaps probable, thai the AJgonkian and Archean will be found
to be divisible only by a somewhal arbitrary line, just as are all other lines
limiting the periods. Even it' thi> should turn out to be the case, the value

the separation upon the basis mentioned i- not lessened. It is, bowevi i .

-aid that there is apparently i <• chance that a very \\ idespread break

will be Bhown to exist between these two periods than anywhere else in the

•logical column, with the possible exception of the break at the base of
the < lambrian.

D, liv; nth

-, pp. ii-

v t he i
it u i-in r by

ig m ill !..• found In the Admin tati iri "f 1 1 . • - Director

i I UDOIl :il

I in print by Wall
.1 D m. Jour. Bel., 3rd 5

• 11 in ptibl bj M r. 8. I '. Emm

Moiintal
k city in I lecembei

Mg mquii i hloh al

iperlor, M Ichig in, and II uron

.. J. W. !■ \ \ VI I, !-- II,

esh water dej

i the ti ill ol

. !•'.
- • lain wiiii • i ii.i t

f i he Ubi W hei her i ii i- ' ■■

and
ime
m Ithoul confuMon for i»ntl eni

I he two follow Ii

the

i long inn'- in
ime.

THE BLACK HILLS CRYSTALLINES PROBABLY ALGONKIAN. 239

It is also clear that to the Algonkiau period belong the series which have
been designated as Hnronian by the Michigan and Wisconsin geologists,
although by no means covering all the rocks here included by the Canadian
survey. The question immediately arises whether the modified elastics of
the Black Hills can be correlated with the iron-bearing series of Lake Supe-
rior. This question . cannot be positively answered. . Newton, from the
uncertain data which at the time of his study was available as to the nature
of these Lake Superior rocks, thought it probable that his slate series was
their equivalent.* Crosby and Carpenter regard these slates as rather the
equivalent of certain of the Taconic schists. As to the probable truth of
the latter correlation I have no opinion, because I have no personal famil-
iarity with the Taconic rocks and do not know whether any of them can
reasonably be regarded as equivalent to the Lake Superior iron-bearing series.
However, the case to-day for placing the Black Hills slates and schists as
the possible equivalent of these series is very much stronger than when
Newton wrote. Belonging to the Animikie, Penokee, and Marquette series
are great thicknesses of mica-slates and mica-schists. These micaceous rocks
are certainly of fragmental origin and have a genesis similar to those of the
Black Hills. Like them, they are staurolitic and garnetiferous in certain
cases. The thick beds of nearly pure quartzite and quartzose conglomerate
which occur in the Black Hills are parallelized by quartzites and conglom-
erates in the Marquette and Penokee areas. Much of the iron-bearing
formations of the Lake Superior region have been shown not to be mechan-
ical sediments, but rather chemical or organic sediments which by subsequent
alterations have been changed into the various forms now found. f In the
Black Hills of Dakota occur considerable beds of rock so like those of the
iron formations of Lake Superior that they cau hardly be distinguished from
them. In the Lake Superior region important beds of iron ore are known
in these formations. Such are not yet known to occur in the hills. In the
Lake Superior region are vast quantities of basic eruptives which occur in
dikes, bosses, and intrusive beds in the fragmental series; similar rocks in
similar relative position are again found in the Black Hills. The chief
lithological difference between the two regions is the presence in the Black
Hills of large masses of granite. The only known parallel to this occurrence
in the Lake Superior iron-bearing series is found in one or two unimportant
dikes.

This lithological correspondence between the Black Hills rocks and certain
of the Lake Superior iron-bearing series is truly remarkable. In cases in
which a set of similar conformable formations occur in a definite order in

i logy of the Black Hills of Dakota, p. 47,

f Origin of the Ferruginous Schists and Iron Ores of the Lake Superior Region, R. D. Irving :
Am. Jour. Sci., 3rd Ser., Vol. X XXII, 1886, pp. 255-272; The Penokee Iron-Bearing Series of Michi-
gan and Wisconsin, R. D. Irving and C. R. Van Hise: Tenth Annual Report U. S. Geol. Survey (in
press).

_'l" i;. VAN HISE — PRE-CAMBRIAN OF THE BLACK EULLS.

Beparate areas in the Bame geological basin, as the Penokee series on the
south shore and the A.nimikie series on the north Bhore of Lake Superior, it
can safely be asserted thai these groups of formations Btand as equivalent
with each other, at least iii a broad way. It cannot l>c said to be proven
that all the Lake Superior iron-bearing series represent the same geological
period. All have, however, been placed by most writers as a part of the
Huronian, and were believed to be equivalent in a general way by Professor
[rving. The Minnesota geologists maintain that the Vermilion iron-bearing
series is older than the A.nimikie. When there is as yet difference of opinion
as to correlation of the iron-bearing series in the Lake Superior region
itself, no definite statemenl can be made as to the equivalence to them of bo
distant a series of rock- as the Black Hills pre-Cambrian. When the
structure of the Black Hills rocks is made out it may be ascertained that we
have tlnr.- a set of formations which are not only lithologically alike, but
occur in the same order a> certain or all of the iron-bearing series in the
Lake Superior country. If this proves to be the case, the evidence for
placing such groups of rock opposite each other will be very strong indeed.
Iii the meantime, until it i- more definitely decided how far lithological cor-
relations can be trusted; it can only he said that the pre-Cambrian rocks of
the Black Hills probably are the equivalent of a part or all of theHuronian
iron-bearing si ries of Lake Superior.

Summary of < !on< lusions.

The Black Hills -dates and schists cannot be divided into two series with
the surface distribution and upon the lithological differences given by New-
ton. These two classes of rock- grade into each other.

The sedimentary rocks have all been so metamorphosed thai the most
marked structures are secondary phenomena, which are entirely independent
of original sedimentation. The true bedding is in many places yel discov-
ble by an alternation of hand- which differ in degrees of coarseness and in
composition. These bands are cut by the cleavage and foliation. It follows
thai the thickness of the serii - is yel to be ascertained.

The largesl area of crystalline schists is a broad zone about the granite,
striking parallel to and dipping at a high angle away from it. A Becond

important area i- aboul I >eadwood.

tive evidence was found of the truth of Newton's conclusion that
the main n ranite in the Bediraentaries of pre-Cambrian age is

l is every reason to believe thai the basic eruptive rock-.

hornblende-schists and diorites, are even more ancient. They

partake to some extent of the structure of the quartzites, Blates, and Bchists

in which ihej in tained, and were regarded bj Newton as au integral

part of these rocks. The} are never found in the granite.

CLASTIC ORIGIN OF THE PRE-CAMBRIAN ROCKS. 241

The prominent features of the pre-Cambrian history seem to have been as
follows : The original sediments were cut by basic eruptives. They were
subjected to great mechanical forces applied in an east and west direction,
so as to produce a vertical north and south slaty cleavage before the granite
appeared. The resulting folding, as shown by the rows of pebble and true
bedding lamina?, is probably complex. After the slaty cleavage and the
first metamorphism in the rocks were produced, but before Cambrian time,
the granitic eruptions, or more properly intrusions, occurred (for there is no
reason to believe that any part of the granite reached the surface) in the
southern part of the hills. The resulting contact and dynamic action de-
veloped the crystalline schists and schistose structure for the most part par-
allel to the main igneous mass.

Whether the crystalline schists in the northern hills were formed at this
same time by the intrusion of large masses of granite at no great depth from
the present surface, or subsequently by the later volcanics, is uncertain. It
is probable, however, that the latter rocks have much to do with their schist-
ose character, even if they were not the controlling factor.

Clastic characters are almost indefinitely retained in fragraental rocks,
however old and deeply buried, unless they have been subject to dynamic
action. Actual movement within a rock rapidly obliterates the evidence of
clastic origin.

The most important conclusion from the microscopic study is that the
quartzites, quartz-schists, mica-slates, mica-schists, and certain of the mica-
gneisses — i. e., the rocks which represent the great mass of the pre-Cambrian
area of the Black Hills — are of clastic origin. In the original detritus of the
micaceous rocks, feldspar and quartz were the predominant minerals ; but the
detritus of the quartzites and quartz-schists differed in that feldspar was un-
important. The quartzites developed from the quartzose detritus by the
enlargement of quartz-grains and the formation of interstitial independent
quartz. In proportion as they are schistose, mechanical deformation with
partial destruction of the fragmental particles has occurred. In the most
schistose phases, dynamic action has broken down the greater number of the
clastic grains of quartz ; yet the quartz-schists are as strong as a quartzite
of the ordinary type. The fracturing and cementing of the particles of the
rigid quartz during the movement within the rock is analogous to ice-flowage
in a glacier. In the mica slates and mica-schists the forces at work and the
results produced upon the quartz detritus have been the same as in the quartz-
ites. Simultaneously with this process the detriial feldspar has decomposed
into an interlocking mass of mica and quartz. To what extent mechanical
movement has helped this alteration is uncertain ; but it is known that a like
decomposition has occurred in rocks in which mechanical effects are slight
which may have suffered little interior movement, although they have been

242 i: VAN IM-i: — PRE-CAMBRIAN OF THE BLACK HILLS.

iiti.l.i- great | In the mica-gneisses, as :i farther change, al the

time the old feldspars were decomposing, new feldspars of a differenl
character were developing. Evenly granular, typical mica-schists and
,,,;,■ i;lVr thus b sen formed from coarse fi Idspar-quartz detritus. En

these final results the positions of the feldspars are marked only by the
relative abundance of mica, while those of the clastic quartzes are marked
onlv !>v a tendency of the broken-down particles of this mineral to be larger
and freer from mica than the av< if the rock.

The microscopical Btudy brings additional evidence in Bupporl of Newton's

iclusion thai the ferruginous quartz-rocks of the Black Hills arc like
much of the iron-bearing formations of the Lake Superior region.

In the development of secondary Bchistose structure, elongation of particles
tak.~ place perpendicular to the lines of force, while fracture takes place
approximately in the lines of force.

The Black Hills furnishes an admirable instance of the existence of broad
belts of >latc> and schists, the structures of which arc thoroughly developed
and their directions entirely independenl of true beddin

In the metamorphism of the rocks the sedimentaries and basic eruptives
have been affected by the same force. In this metamorphism, both in the
fragmental and crystalline rocks, profound mineralogical changes have

curred. A schistose structure has been produced in both. Wethus have
in the Black Hill.- crystalline schists of sedimentary ami of eruptive origin.

The Black Hill- rocks exhibit a remarkable lithological analogy to certain
of the iron-bearing series of the Lake Superior region, which in the past
have been included under the term Huronian. While this correlation is
not beyond doubt, there is no question that these series in common belong
t'> tie- AJgonkian period.

This paper make- dm pretension i" completeness. To describe in detail
the many phases of the rocks of the Black Hill- ha- not even been attempted.
The object has been t" arrive at the structural relations ami genesis of cer-
tain among the rock- which occur in the pre-Cambrian area, so tar a- the

material at haml would allow. 1 cannot close without saying a word in

lition of the work done by Newton. My surprise is not that I find a

- which seem to hud to conclusions differenl from his, hut that he

i much. The an I'd in a single season i- of va-l

1 i only had the geology of the pre-Cambrian rock- to he worked
that of the great fossiliferous series there found. The many
l>i .-il history presented by the region had to he considered.

It was inevitable that the most of Newton'- time should b n to deter-

mining tin I >. >im i' the periods rather than in describing in detail their

■ on.- who first into a i egion, t he fossiliferouE

EXCELLENCE OF NEWTON'S WORK. 243

demand the greater attention. Not only this, but at the time of Newton's
work the microscope had been little applied to the study of the pre-Cambrian
rocks in this country. The geologist of to-day has not only Newton's report
to build upon, but those of the army of workers who in the past decade have
been engaged in a study of the crystalline schists. In this paper I have
necessarily emphasized differences, but I close with a feeling of admiration
for the general excellence and fidelity of Newton's report and Gilbert's
editorial skill.

XXXtl — Bum,. Geol. So* . Am., Vol. 1, I88i>,

PLATE 1.

Fiot B( I. — Mi J" tht o ght.

\ large fragmental particle of feldspar has been to a considerable extent alt<-n-.l t" blot 1 1

Itange has « holly destroyed the exterior of the grain, but t lie Interior appears in the

i unit, i igainat the feldspar grain upon one shle is a large particle "f quarts.

background Is finely crystalline quart/, an'l biotite, in which are contained a few larger parti-

■

I-1..I BJ I I I :■ 1. /" tin y>n i tht.

Theeztentol the decomposition of the feldspar to quartz ami mica la now appreciated, these

minerals and the residual feldspar making nn intricate crystalline complex. The apparently

simple elongated quartz-grain "f the previous figure is found to have been broken Into aeveial

ri.\ i i

l''l..i ia: 1. — M In tin <■ lilt.

id consists of mica and quartz, much of the former being muscovite. The

■ • \ double arrangement of these two micas Is very distinctly shown,
direction of the muscovite being nearly perpendicular i" thai of the biotite. It it

■ the biotite particles are unusually wide, transi erae to the cleavage. Thi* double

■ i the mica corresponds to the two direct i<>n< "i la mi nation of the rock as Been in

I In- larger Bakes "f mica ai e regarded as having begun t" develop al the time "i

when a new force nearly at right angles to the old one sat in,

numerous other Individuals of mica began to form with their l< rpendicular to the

ndividuals continued, however, to grow.

I'h.i i:i •_'. — .1/ ;ht.

i i uhistsol the Black mils. I ground consists ol

with their Ion i lirection. The mica includes both mu

■ i which, like the quartz particles, have > very perfect linear-parallel

:::0L. SOr

VOL 1, PL 4

FIG. 1-MICACEOUS GREYWACKE. ORDINARY LIGHT.

FlG 2— MICACEOUS GREYWACKE. POLARIZED LIGHT.

MOSS ENG CO.. N. Y.

'.'

:. PL 5.

FIG. 1— MICA -SLATE. ORDINARY LIGHT.

FIG 2-MUSCOVhTE-BIOTITE- SCHIST. POLARIZED LIGHT.

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA

VOL. 1, PP. 245-286

OROGRAPHIC MOVEMENTS IN THE ROCKY MOUNTAINS

S. F. EMMONS

WASHINGTON

PUBLISHED BY THE SOCIETY

April, 1890

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA

Vol. 1, pp. 245-286 April 7, 1890

OROGRAPHIC MOVEMENTS IN THE ROCKY MOUNTAINS.

BY S. F. EMMONS.
(Read before the Society December 26, 1880.)

CONTENTS.

Page.

Introduction and Historical Review 245

Pre- Cambrian Land . 256

Early Palaeozoic Land 259

The Late Palaeozoic Movement 2(31

Late Palaeozoic Land 263

The Jurassic Movement 267

Jurassic Land 209

The Post-Cretaceous Movement 280

Introduction and Historical Review.

That the vast succession of mountain ranges and elevated plateaus and
valleys which go to make up the Cordilleran mountain system in the United
States must be the final result of a number of orographic movements occur-
ring at different periods of the earth's history was recognized in the earliest
geological explorations in that region by Marcou, Newberry, Le Conte, and
others. It was not, however, until systematic examination of large areas,
both topographical and geological, had been instituted, which permitted the
construction of geological maps of a substantial degree of accuracy, that
any attempt could be made to determine the number and comparative im-
portance of these movements and their relative position in the structural
history of the region. Even then the conditions under which such exami-
nations were conducted, necessitating the covering of large areas in a given
time, which time was dependent more upon the geographical extent of the
area than upon the complexity or relative importance of its geological struct-
ure, did not admit of an exhaustive study, and many significant facts were
necessarily overlooked.

It will only be when the whole Cordilleran region shall have been accu-
rately surveyed with much greater detail than has hitherto been practicable
that its complete and accurate history can be written. Meantime much
additional light can be thrown upon the subject by detailed examination of

XXXIII— Bun. Gkoi,. 80c. Am., Vol. 1, 1889. (245)

24G - I. EMMON OROGRAPHK MOVEMENTS,

cially disturbed districts, where in the limited time at their command the
earlier explorers* of necessity overlooked or but imperfectly studied many
i importance in their bearing upon the general orographical history of
the region. Ii has been my lot during the past ten years to make a number
of such examinations, incidental tn a study of the ore deposits of important
mining districts in various part- of the Rocky Mountains in Colorado, and
thus gradually to gather together a Dumber <>i' tacts bearing upon this >ul>.
ject. Although these facts arc not sufficently complete for an exhaustive
discussion of the subject, I have been led to attempt to construct from them,
ami from such information derived from the work of others in the region
:i- -.-, med pertinent and trustworthy, a slight historical sketch of the oro-

iphic movements of the Rock) Mountains between Archaean and Tertiary
times, with special reference to two important and hitherto not generally
lized movements, the one during the Carboniferous, the other during
the Jurassic epoch.

Many of t lu* conclusions at which I had arrived have to a certain extent
been forestalled by my colleague, Dr. C. A. White, in his admirable add n
on the North American Mesozoic delivered at the last meetingof theAmeri-
can Association, at Toronto, Canada, but as they had Ween reached inde-
pendently and from a Boraewhat different standpoint I have not thought it
advisable on that account to modify what I had written.

Before presenting this -ketch it may be well to review briefly the princi-
pal conclusions that have been arrived at by members of the various geo-
logical Burveys thai have examined this region. They will be taken as far

:i» possible in the order in which the field work of each was done.

Fortieth Parallel Survey.- -The orographic movements determined l>\ the
ilogists of the Fortieth Parallel Survey are given l»\ Mr. King ■ as fol-
low

1. Post-Lauren tian,

A ich.enll.

r i' tic.

I. Post Jurassic.

I lUS.

V' rmillion < In ek | Wasatch | Koc< ne
7. Post-G reen River Eocene.
r • Bridgi i cene.

In. post Mini i ne

II I ut"T I'll- ■ ic

I 2. Post I'll"

I ;. Paulte ■•: Lhi 1 1 ; • >i ical Period.

■

MOVEMENTS RECOGNIZED BY CLARENCE KING. 241

Of these he considers that the work of the first movement was to throw
the original crust of crystalline sediments into waves within the present prov-
inces of the Wasatch and of the Rocky Mountains. His post- Archaean move-
ments, which produced the land areas in the Cambrian seas and would now
be designated post-Algonkian, extended over the whole breadth of the Cor-
dilleras.

The post-Palreozoic or post-Carboniferous movement produced a continental
elevation from the Wasatch westward to longitude 107° 30'. Its effects wrere
most marked at the western edge of this area; and east of it, with the excep-
tion of slight unconformity by erosion in the Wasatch,* no direct proof of
movement was observed, though there is evidence of shallow water deposi-
tion in the succeeding Permian and Mesozoic sediments.

The post-Jurassic movement was likewise considered by him to be mainly
confined to the western part of the Cordilleran system, the evidence of un-
conformable deposition found at that time being too slight to justify the
assumption of the general extension of the movement to the east of the
Wasatch. It is to this movement that he ascribes the original formation of
the peculiar parallel ranges of the geological province of the Great Basin —
the Basin Ranges, as they are called — a movement due to tangential com-
pression resulting in contraction and plication f which he distinguishes from
the later movements in the same region, presumably Tertiary or later, in
which there are few evidences or traces of tangential compression. The
principal effect of this later movement has been the faulting and uplifting of
irregular areas with little or no attendant plicatiou. Where the effects of
the earlier movements were not felt, or have been obscured by erosion and by
later sediments and extensive flows of eruptive rock, only those due to the
later movement are readily manifested. Hence a number of geologists,
whose observations have been principally in such parts of the region, have
considered it characteristic of the whole and given the name " Basin Range
structure " to this later phase of its orography.

The post-Cretaeeous movement was principally manifested east of the
Wasatch, the Uinta uplift dating from this period, and the principal eleva-
tion of the Rocky Mountain region and the final shutting-out of ocean
waters from the whole Cordilleran system east of the Sierra Nevada being
due to it.

The subsecpient movements during Tertiary and Recent times were foldings,
upheavals, and subsidences within a continental area, to be measured not by
their relations to sea level, but to that of adjoining land elevations or inte-
rior lakes. Thus, those numbered 6, 7, and 8 are shown in successive eleva-
tions of the Uinta mountains and in modifications in the adjoining Tertiary
lakes whose sediments were largely derived from the abrasion of the broad
crest of that range.

I >p. cit., p. 228. t Op. eit.,p. 744.

24S - I. EMMON OROGRAPHIC MOVEMENTS.

/• oeU Survey. — Major J. W. Powell* in his flrsl account of the Colorado
river, explains the tortuous nature of the upper portion of its course (the

■ I, river athwar! the Uinta mountains on the hypothesis that the coun
being already determined previous to the uplift of these mountains its bed
was deepened paripauu with the slow uplifting of the mountains, furnish-
ing an illustration, which has been widely quoted in text booksf and els
where, of the bIow rate of mountain elevation. This hypothesis involves a
conformable deposition of all the beds involved in or affected by the Dinta
fold, Bince it is evident that sedimentation could not be going on in a region
through which a river was running and cutting down or corrading its bed.
1 1 . ii.-. the Uinta fold should have commenced after the deposition of the
latest sediments deposited along its flanks — that is. in Tertiary or Recent timi 8.
In lii- second volume, however, he recognizes tin1 fact that tin- Uinta fold
was formed at the close <>i' Mesozoic time, and that during Tertiary times
no less than four lake- were successively formed and drained during dry-land
epochs, in which 8,000 feet of sediments were accumulated, largely from
materials resulting from the degradations of the Uinta fold, ami that th<
Bediments did not arch over the crest of the Uinta fold. He found, what
hail not been observed by the geologists of the Fortieth Parallel, an uncon-
formity by erosion between the Carboniferous and underlying Uinta sand-
stone, to which he assigned provisionally a Devonian age, showing that a land
surface must have existed there during <>v previous to Carboniferous time.
II. ;il-., recognized, in accordance with the previous observations <>t' the
Fortieth Parallel geologists, the existence of a submerged cliff of Eozoic
rocks at Red creek Red Creek quartzites) against which 8,000 feet of Uinta
sandstone were deposited. He considers Cenozoic time as the main mount-
ain-building epoch, and regards the Park province or Rocky Mountains as
of the Uinta type of structure — that i-. that the sedimentary beds now rest-
ing against their Hanks formerly formeda complete arch over their crests, or
that they were completely submerged during the deposition of these beds.

Win > h r Sun-i ii. Of the geologists of the Wheeler Survey,} Gilbert re<
ni/.es in Utah, Nevada, Arizona, and New Mexico the universality of the
unconformity between Archaean and succeeding sediments, whether Cambrian

later. He accepts King's assignment of the Jurassic a- the date of orig-
inal formation of the Basin Ranges, but considers that the Plateau region
was submerged from early Palaeozoic t" the close of Mesozoic time, though
cted to oscillations of level producing changes in depth of waters and
[uently in characl diments. While remarking upon the mea

I ■ Expl ■ ■ ■ ido Kiver ol the

\ v ..i the Eastern Portion "i the Uinta

■ i i. "f Geology.

J Ian; Vol. Ill, Waahlngtoi eld work, 1871,1872, and

MOVEMENTS RECOGNIZED BY SEVENSON AND PEALE. 249

representation of the Upper Silurian and Devonian both in fossils aud in
strata, he finds no evidence to prove that the region was lifted above water
daring these times, but considers that the general movement of the land dur-
ing Palaeozoic time was a subsidence, and that where Carboniferous lime-
stone rests directly upon the Archaean there were islands in the early Palaeo-
zoic seas which became submerged in Carboniferous time.

J. J. Stevenson, in the course of his explorations in Colorado and New
Mexico in 1873, noted several unconformities and drew the following con-
clusions:

"The Rocky Mountain system, therefore, is the result of four especially marked
upheavals, the first, at the close of the Carboniferous ; the second, at the close of the
Trias ; the third, at the close of the Cretaceous, and the fourth, during the Tertiary.
Of these, the first and the third were the most general in their effect."

He also recognized the unconformity of overlying beds with the Archaean.
In his subsequent more detailed work in southern Colorado and northern
New Mexico he does not seem to have found reason to modify these general
conclusions.

Hayden Survey. — The beautiful geological atlas of Colorado,* showing the
result of the combined labors of the various members of the Hayden Survey,
furnishes a most valuable record of the geology of the Rocky Mountain region.
Unfortunately no systematic discussion of their field observations has yet been
made to present the final orographical conclusions which would be drawn with
the consensus of all who were engaged in the work. In the absence of such
a discussion inferences must necessarily be drawn from the graphic repre-
sentation of facts given by the maps, where personal verification in the field
has not been possible. Such verifications as have been made have proved
the substantial accuracy of the geological outlines laid down on these maps,
except in southeastern Colorado and in the San Juan mountains, where at
the various points examined the facts of nature show such wide divergence
from these outlines, as laid down by Mr. Endlich, as to throw serious dis-
credit upon all of his field work.

Dr. A. C. Peale, of this Survey, has since summarized the results of his
own observations in Colorado as follows : f

" 1st. In very early times in Colorado there was Archaean land rising above the
Palaeozoic sea. As the Carboniferous age progressed this land diminished by en-
croachment of the sea, due to subsidence of the land. This subsidence continued
through Triassic, Jurassic, and Cretaceous time into the early Tertiary.

:'2nd. At the close of the Lignitic, there was a physical break followed by subsi-
dence (at least locally), and subsequently by elevation after the deposition of the Mio-
cene strata.

* Field work 1873, 1874. 1S75, 1870.

tJAmer. Jour. Sci., 3d Ser., Vol. XIII, Mar. 1877, p. 181.

250 S. I. I.MM<»\ OKOGRAPHK MOVEME2*

1. The elevation of the Rocky Mountains, as we now see them in Colorado, is
the result of an elevation commencing in early Tertiary time and continuing through
the period, i I aps at tl of the Lignitic and after the deposition of

M i ene strata. "

This was written at the time when Dr. Peale, in accordance with the views
of hi- chief, Dr. V. V. Hay den, regarded the Lignitic Laramie) as of Ter
tiary a§

Black Hills Survey. -In the Black Hills of Dakota* Newton and Jenney
recognized two distinct series of crystalline schists, with some faint evidence
of unconformity between them. Thegreat breaks determined by them were
between these crystalline schists and the Cambrian (Potsdam sandstom
More recently W. 0. Crosbyt has found evidence of an uplift of the region
at the close of the marine Jurassic.

orado Plateau Region. Gilbert, in his Geology of the Henry Moun-
tains,^ remark- on the physical break at the close of the Cretat as, and

notes three unconformities by erosion, one at the close of the Carboniferous
arid two within the -eric- called by him Jura-Trias.

In the preface to Captain Dutton's work on the High Plateau-. J Major
Powell states with regard to the Plateau province —

• A marked unconformity exists between the Silurian and Devonian rocks; another
between the Devonian and Carboniferous; another, but not so well marked, between
the Carboniferous and Mesozoic, and lastly an unconformity between Cretaceous and
Ti rtiary is usually well defined."

In the region of the Grand Cafion of the t lolorado, Captain Dutton notes,
besides the universal unconformities at the close of the A.rchsean and the
Cretaceous, that the Carboniferous rests unconformably upon the Silurian
or Devonian, as the case may be. He also timls unconformities by ero-
sion between Carboniferous and Permian, between Permian and Trias, be-
tween Trias and Jura, and between Jura and Cretaceous. He considers
that the Carboniferous was deposited in deep waters, but that during the
Permian and Mesozoic, shallow-water conditions prevailed; also that the
Eocene was a fresh-water deposit, that a slow elevation began about the
middle of this epoch, and that the Colorado river commenced as a drains
channel of the Eocene lake in early Tertiary times, gradually eating its way
hack until it reached its presenl extension, and cutting across an} elevations
produced during subsequent movements as they rose without changing it-
already determined com

I find it difficult to reconcile my own observations in the Uinta mountain

\V:i-Iiii.l-
[| 'I

field

THE EVIDENCE OF THE WYOMING CONGLOMERATE. 251

•region with the views of either Powell or Dutton, with regard to the deter-
mination of the course of the Colorado river ; and I am inclined to think that
future investigation will prove that they have placed it at too early a date.
I have already shown * that the Wyoming conglomerate (Bishop Mountain
conglomerate of Powell), which has escaped erosion along the flanks of the
Uinta mountains, is so situated as to prove that it must once have extended
over the entire eastern end of the mountaius through which the canon of
the Green river is now cut, forming a nearly level surface at an altitude
corresponding to a present elevation of between 9,000 and 10,000 feet, and
that the river must have initiated its present meandering course over this
surface as a superimposed valley. This conglomerate is considered by all
who have examined the region to be of very late age, either Pliocene or
Quaternary, though no fossils have yet been found in it. It is everywhere
horizontal and undisturbed, showing no stratification planes, but at one
exposure shows a thickness of 200 feet of rounded pebbles derived from the
Uinta quartzite, cemented iuto hard rock by an abundant lime cement. The
situation of its remaining exposures is such that I cannot conceive of the
possibility of the existence of the canon of the Green river during its
formation. While in the Plateau province south of the Uinta mountains no
beds have yet been discovered that are known to be of later than Eocene
age, the region has not yet been examined with sufficient detail to make it
certain that they have not existed there. Such beds would have been the
first to be affected by the enormous erosion to which the entire region has
been subjected, and the present limited extent of the Wyoming conglomerate
(which has doubtless been exceptionally protected by its position along the
flanks of the range), as compared with that it must once have had, proves
how thoroughly such recent deposits could have been carried away by recent
erosion.

In more recent observations in northern New Mexico,f Captain Duttou
found upper Carboniferous beds resting directly on the Archaean in theZuni
plateau and the Nacimiento mouutains, the Cambriau, Silurian, and De-
vonian being wanting.

In more detailed studies of previously examined sections in the Grand
Canon of the Colorado, Mr. C. D. Walcott J has recoguized a great thickness
of comparatively unaltered saudstones, shales, and limestones (the Chuar and
Grand Canon series), which he considers of Algonkian age, and which rest
unconformably upon sandstones and eruptive granites of undetermined age.
A distinct unconformity of angle exists between the Algonkian and upper

* Descriptive Geology: Vol. II, Fortieth Parallel reports. Washington, 1887, pp. 194 and 205 (field
work, 1871).

t Mount Taylor and the Zufii Plateau : Cth Ann. Rep. Director U. S. Geol. Survey. Washington,
1885, p. 132 (field work, 1881).

t Am. Jour. Sei., 3d ser., vol. XX. p. 221 ; vol. XXVI, p. 437; vol. XXVIII. p. «1 ; vol. XXX I 1, p.
154; vol. XXXV. p. :i'M ; vol. XXXVII, p. 374; vol. XXXVIII, p. 2'J ; and Bull. U. S. Geol. Survey,
No. 30, 1886, p. 15.

252 S. K. EMMONS — OROGRAPHU MOVEMENTS.

Cambrian (Tonto beds). He also observed unconformities by erosion be-
tween, first, the upper Cambrian and Devonian ; second, Devonian and lower
Carboniferous; tliird, upper Carboniferous and lower Permian ; fourth, lower
Permian and upper Permian. A similar unconformity between Algonkian
and upper Cambrian was observed by him in Llano county, Texas.

With regard to the Mr-o/oic, Dr. C. A. White* first made the following
suggestion, based on the finding of fresh-water Jurassic fossil.- in Colorado
and Wyoming:

••In conclusion, I think it may be safely assumed that the great inland portion <>f
our continent was nol so permanently the seat of oceanic waters during the Mesozoic
times as has been generally supposed."

I have already in a previous publication stated my belief that the Archaean

areas in Colorado occupy the sites of mountain elevations that were uplifted

above tin ean in post-Archsean time, and which in a more or less modified

form have constituted hind areas ever since — that is, that in the times of the
greatest general depression of the region they were never so completely sub-
merged as to admit of continuous sedimentation over them, hut some mount-
ainous islands always existed, from the abrasion of which the sediments in
the adjoining seas were formed. This view is opposed to that held by the
late Dr. F. V. Haydeu, and also to that expressed by Major J. \V. Powell
in his geology of the eastern Uinta mountains, t both of which involve a
former complete arching over of the present crests of the mountains by the
strata now upturned along their flanks. It had, however, already been ad-
vocated by Mr. Clarence King J in his Systematic Geology, and by Dr.
A. ( '. Peale§ of the Hayden survey.

The necessity of this view was impressed upon me by the structural con-
dition- of the heds resting on the eastern flanks of the Colorado range long

before I had made any special studies of Colorado geology, and my subse-

quenl field work there has only served to confirm its general correctness hy
the persistent evidence it ha- afforded of the littoral character of the sedi-
ment- along the assumed shore line.-, which changes rapidly as they are left ;
and by tin- character . if much of the organic life whose remain-, found in
these sediment-, indicate the vicinity of land areas, and .add to the impossi-
bility of explaining in any other way the peculiar stratigraphies! relatione
observed.

In tracing the effects of orographic movements upon the cart h's cru-t . a

marked contrast is noted between the region- of violent disturbance, gener-
ally mountainous areas, and those in which the strata -how little chai
from the horizontal position in which they weir originally deposited, which

ii.

rn I'ortion of the Uinta Mountains. Washington, 1876, p. 26 el
o.-ii, Paralli I Reports. vo\ I. i-

A mi JOUI . V0\. Mil. 1>77, p. 1-1.

DEARTH OF EVIDENCE OF UNCONFORMITY. 253

are characteristically represented by the great plain areas of the present da v.
In the former, the strata show the effects of powerful and repeated tangential
compression, not only in their steeply inclined positions and sharp folds and
faults, but in the frequent and marked angular unconformities between beds
deposited before and after an orographic movement. In the latter, on the
other hand, the inclinations of the strata diverge but little from a horizontal
position, the folds are but gentle undulations or monoclines broken by
faults of moderate displacement, and no angular discordances between suc-
cessive strata are to be observed, whatever orographic disturbance may have
intervened between the times of the respective depositions.

Nowhere is this change of condition more marked and sudden than in the
Rocky Mountains of Colorado. In leaving a mountain area one may pass
in a mile or two from steeply upturned and even reversed strata, showing
evidences of violent movements accompanied by long periods of erosion
before succeeding beds were deposited, to an adjoining plain where the same
beds rest in horizontal position and in perfect stratigraphical accordance one
over the other, and where the only evidence of erosion on the beds below
the horizon of the movement may be a variation in their asrarregate thick-
ness. Not only is this true of the outer flanks of the mountain ranges, but
it can also be observed to hold good for many of the interior depressions
which would seem to have been either valleys or arms of the sea throughout
the various phases of the geological evolution of the region.

It is evident, therefore, that except in highly disturbed regions actual evi-
dence of unconformity must be extremely rare, the parallel succession of
beds after an orographic movement, or parallel transgressiou as it is desig-
nated by European geologists, being far more common than actual discord-
ance of stratification ; but even in highly disturbed districts, I have found
that a very marked discordance of stratification is not always shown by an
actual angular unconformity along the line of dip, but that its evidence is
readily found only in variations in the strike between beds deposited before
and after an orographic movement, or, what amounts to the same thing, by
the observation that the later beds rest at different points upon different
horizons of the earlier series of beds. The explanation of an extreme case
of conformity in angle of dip, combined with the greatest variations in strike,
which has come under my observation, is very readily apparent and, with
local modifications, is doubtless applicable to all similar structural phenom-
ena. In the given case, the beds already deposited were by an orographic
movement thrown into a series of folds whose axes had a general east and
west direction. After the crests of these folds had been planed off by erosion ,
a second series of beds was deposited upon them, producing a complete suc-
cession of beds with no discrepancy of angle, along an east and west line in
the troughs of the synclinal folds, but with gaps of varying width in the succes-

'_!•"! S. I'. EMMONS — OROGRAPHIC MOVEMENTS.

Bion of beds on the crests of the anticlinals. In the following movemenl
both series were thrown into a series of folds the prevailing direction of
whose axes was aorth and south, or at right angles to the preceding folds ;
and after these folds had been eroded, in the beds left standing with a steep
western dip, the evidence of the earlier folds is found only in their irregu-
larly-waving line of strike as compared to the i iparatively Btraight one of

the later beds, while the angle of dip in the two series is in many cases per-
fectly conformable, and what variations may exist in other cases is generally
undistinguishable, either from its Blight amount or from the unfavorable
position of the exposun

In weighing the evidence for or against an orographic movement in a
given region it would seem, therefore, that the positive proof afforded by one
or two instances of unconformity should overbalance the negative testimony
of many instances of apparent conformity.

In endeavoring to trace out the orographical history of the Rocky .Mount-
ain region I have followed the method of reconstructing in my mind the
probable outlines of its various land-masses when a period of sedimentation
began after the close of an orographic movement, and the changes produced
in those outlines by each succeeding movement.

Rocky Mountain Region. — The mountain area which is referred to in this
paper as the Rocky Mountain region, is a north and south belt about 150

miles in width, extending from northern New Mexico through the State of
Colorado into southern Wyoming, a distance in round numbers of about
100 miles. As the land areas at the close of the successive movements espe-
cially referred to correspond more or less closely to the areas of the principal
mountain ranges, areas whose general lines of uplift it may be assumed were
determined very early in its history, perhaps at the close of the Archaean,

they will he referred to as islands under the name- that are now -applied

to the ranges. Their general disposition is as follows: The mountain uplift
fronting the Greal Plains, which as a whole has a meridional trend, is divided
by depressions having a general northwest trend into three more or less dis

tinct ranges, whose northern continuation.-, leaving the line of uplift which

fronts the Plains, trend to the northwesl and thus produce :i structure en
echelon for the whole system. The northern and most extensive of thes
the Colorado range, extends from Pike's peak northward to the Colorado
Btate line and then splits int.! two distinct uplifts on either Bide of the broad

elevated valley known a- the Laramie plains. The eastern of the86 uplifts,

tie' Laramie hill-, was a submerged reef in Palaeozoic times and has a Bome-
what broken connection by -mall projections of Archaean exposures with the
Black Hills of Dakota. The western uplift, known a- the Medicine Bow
range, trends northwestward between the Laramie plains and the North

park, at one time having been connected with the northern end of the Park

UPLIFTS AND BASINS IN THE ROCKY MOUNTAINS. 255

range or Grand Encampment mountains. It disappears beneath the pres-
ent east and west depression of central Wyoming ; but a submerged line of
uplift, proving a possible connection with that of the Wind River mountains,
is found in the Archaean exposures of Rawlins peak and the Sweetwater
mountains.

Immediately west of the Colorado mountain mass are the broad valley
depressions of North, Middle, and South parks.

Southwest of Pike's peak and separating the Colorado range from the Wet
mountains is a bay-like depression extending northwestward from Canon
City toward the southern end of the South park.

The Wet mountains form the mountain front from Canon City south to
Huerfano park, and have a small depression or park to the westward, known
as the Wet Mountain valley, which is of less orographical significance than
those already mentioned, having once probably been part of an elevated
region, brought down to its present position by faulting and erosion in more
recent times. The northwestern continuation of the Wet mountains has
also lost its former topographical importance, but is recognized geologically
in the Arcrnean area along the Arkansas river, west of the Royal gorge.

Huerfano park is a second bay-like depression, which, if extended to the
northwest, would merge into the Wet Mountain valley. It separates the Wet
mouutains from the Saugre de Cristo range, which, rising gradually from
the plains of New Mexico, forms the east front of the Rocky Mountains as
far north as Huerfano park, and then trends northwestward, forming the
western boundary of that park and of the Wet Mountain valley in the same
general line of uplift as the Sawatch range.

The original Sawatch uplift, now divided by the upper Arkansas valley
into the Sawatch and Mosquito ranges, formed the earlier western boundary
of the South park depression, as the Mosquito range does to-day.

The western boundary of the Middle and North parks is formed by the
Park range, a line of uplift also having a northwesterly trend parallel to
that of the Sawatch and set off en echelon a little to the northeast of it. Its
northwestern end is known as the Grand Encampment mountains, and the
southern continuation, which at times has been separated from it, is called
the Gore mountains.

To the southwest and west of the Sangre de Cristo is the great valley
depression of the San Luis park, on the same general meridian with the
other parks, but geologically distinct in that it is probably of more recent
formation, since there is no evidence that Mesozoic sediments were ever
deposited in it. To the northwest, and separating it from the head of the
Gunnison and lower Grand rivers, is a broad area of moderate elevation
now buried beneath extensive bodies of igneous rocks. But little can now
be learned by actual observation of the structure of the underlying rocks of

XXXIV— Bull. Gf.ol. Soc. Am.. Vol. 1, 1889.

256 S. I. EMMONS — OROGRAPHIC MOVEMENTS.

these two areas, owing to their almost unbroken covering of alluvial and
eruptive material ; but, as will be seen later, it may be inferred from the
structural conditions of the adjoining regions on the north and cast that
another elevated island once occupied some portion of it. possibly con-
nected with tin- southern end of the Sawatch island, which has disappeared
under the influence of erosion or local subsidence.

A western meridional line of elevation beyond those above mentioned is
formed by the San Juan mountain- west of the San Luis park, the Elk
mountains west of the Sawatch range, and the White River plateau. The
two latt< r arc closely connected together, but arc separated from the greater
uplift of the San Juan mountains by the broad east and west depression of
the Gunnison valley. This line of elevation, as compared with that to the
east, is characterized by having been the scene of intense eruptive activity
in late Afesozoic and Tertiary times: and the same evidence of eruptive
activity is seen on the same north and south line in the Elkhead mountains
on the westein thinks of the Park range.

It is only of the beds deposited during and subsequent to Cambrian times
that the outcrops are exposed in sufficient continuity to justify an attempt
at differentiating the land areas around which they were deposited.

Pre-Cambria n Land.

Of the extensive series of clastic sediments which the investigations of
[rving and his colleagues in the Lake Superior region have shown must
bave been deposited upon the Archaean basement of distinctly crystalline
rock- previous to the earliest Cambrian, for which the general term Algon-
kian is now proposed, only a few isolated exposures have yet been discovered
in the Rocky Mountain region, and these have not been sufficiently studied
to attempt any correlation between them. With regard to the earlier land
areas, therefore, only a few general conjectures can be formed.

Algonkian Exposures. — Between the western Archaean continent (of which,
a- King has shown, the present Wasatch uplift must represent the eastern
Bhore-line and the Archaean islands of the Rocky Mountain region, it may
1m- assumed that a general depression existed in Algonkian time commen-
surate with that which has obtained in later periods. The Grand Cafion
and Chuar -'-nes, which Walcott has assumed to he of Algonkian age, and
on the upturned and eroded edges of which rest upper Cambrian beds, arc
on the general north and south line of the Wasatch uplift. Idie only other
known pre-Cambrian exposure in this depression i- that of the Red Creek
quartzites of the eastern Uinta mountains, which were classed a- Suronian
by the Fortieth Parallel geologists, and probably belong to one of the Algon-
kian Beries. They Berve to show that the Uinta uplift, which is ■>)' post-

ALGONKIAN AND CAMBRIAN EXPOSURES. 257

Cretaceous age, probably owes its position to a pre-Cambrian ridge which
acted as a buttress or point d'appui to the forces of compression which pro-
duced this most remarkable and exceptional anticlinal fold of 30,000 feet of
practically conformable beds. The series of schists, slates, and quartzitesof
the Black Hills, which have hitherto been classed as Archaean, are probably
of Algonkian age also.

In the Rocky Mountain region Mr. Arnold Hague found a considerable
thickness of quartzites resting on the Archaean in the Medicine Bow range at its
northern extremity, and an isolated patch of quartzite and conglomerate is
known to exist on the east flanks of the Colorado range near Boulder. In
the hills east of the Arkansas river at Salida and south of the South park, Mr.
Whitman Cross discovered a thickness of about 10,000 feet of slates and schists
entirely distinct from the Archaean and probably unconformable with it. On
the north slope of the San Juan mountains near Ouray, I have found over
10,000 feet of closely folded quartzites, conglomerates, and slates of pre-Cam-
brian age, and believe that the Quartzite peaks in the southern portion of
this region are probably composed of the same series of rocks.* Quartzites
have also been noticed connected with the Archaean of the southern end of
the Sangre de Cristo range which may on general grounds be assumed to be
the remnants of some Algonkian beds.

While these various exposures are too isolated and have been too little
studied as yet to justify an attempt at correlation between them, they are
easily distinguished from the Archaean or basement rocks even when not
found directly associated with them. The latter, so far as the great areas
exposed have been studied, are distinctly crystalline, consisting mainly of
granites, gneisses, mica and hornblende schists, with none of the limestone
or apparently fragmentary beds which confuse the student of Archaean de-
velopments in the east ; while in the former, secondary alteration is either
very slight throughout the series or limited to certain beds, so that there can
be no doubt of their clastic or mechanical origin.

The character of the material of which they are composed and their great
thickness show that they result from a long-continued abrasion of high
Archaean laud-masses in their near vicinity. It is to be noted, moreover
that all the Algonkian exposures, with the exception of that near Salida, are
on the outer flanks of the area which has been designated the Rocky Mount-
ain region. Their beds are steeply upturned or sharply folded, and all
Cambrian or later sediments rest unconformably upon them, as upon the
Archaean ; hence there must have been at least two and possibly more oro-
graphic movements between Archaean and Cambrian times.

Cambrian Exposures. — At the base of the Paheozoic section in the Wasatch
mountains, as exposed in Big Cottonwood canon, are 12,000 feet of quartzites

* This opinion is confirmed by Mr. Van Hise, who has visited this region during the past summer.

258 S. I'. EMMONS — OROGRAPHK MOVEMENTS.

and slates, resting unconformably on the granite body of Little Cottonwood
(•anon and upon a Beries of schists which form the western flank of this body .
These were classed by the Fortieth Parallel geologists as Cambrian, while the
schists were assumed on lithological grounds to correspond with the Red < 'nek
quartzites of the Uinta mountains. In my study of the Uinta range in 1*71
I found only upper Carboniferous beds, as determined by their fauna and
their lithological correspondence with already defined horizons in the adjoin-
ing Wasatch range, and considered thai the great thickness of quartzites,
conglomerates and shales underlying them in apparent conformity and form-
ing the core of the range belonged to the silicious or middle member of the
Carboniferous. Powell, however, haying found, in the canon of the Green
river at the eastern end of the mountains, an unconformity by erosion betwe< a
the upper and lower portion of these sandstones, I assumed that the lower
portion, the Uinta sandstones, must correspond to the Cambrian quartzites
of Big Cottonwood canon.* In his later examination of the Big Cotton -
wood section, Mr. Walcott found lower and middle Cambrian faunas in the
upper 2,000 feet of the Big Cottonwood quartzites, and classed the lower
10,000 feel as Algonkian. According to this classification the Uinta sand-
stones would probably be of Algonkian age, but of a later period than the
Red ( Ireek quartzites.

In the Grand (anon region, throughout the Rocky Mountain region, in
the Black Hills of Dakota and, so far as known, in Texas, New Mexico,
and Arizona, only upper Cambrian beds were deposited. It must therefore
be assumed that during early and middle Cambrian times, while the Big
Cottonwood beds were being deposited, these regions were elevated above
the ocean; but that a progressive subsidence was going on which initiated a

cycle of deposition in the Rocky M tain region extending from upper

Cambrian to middle Carboniferous time.

The beds deposited during this interval are of extremely limited thickness
;i- compared with that of corresponding horizons in Utah and Nevada, no
exposures thus far examined showing as much as one-tenth of the thickness
represented in the Wasatch section. Their fauna also has thus far proved
to be extremely meager. A fairly uniform succession in character of sedi-
ii m -ii t is observed throughout the region, the Cambrian commencing with a
fine basal conglomerate indicative of an advancing shore-line, followed by
varying thicknesses of sandstones, which pass upward through calcareous
sandstones and shales into silicious limestones in the Silurian and pure dolo-
mites or limestones in the lower < ail iferous, with a somewhal abrupt pas-

e into clays and sandstones above, showing evidence of shallow-water
deposition.

Such palseontological evidence as has Keen obtained prove- the existence

Poi i leth Parallel Vol II, p. 100

THE ABSENCE OF THE DEVONIAN. 259

of faunas characteristic, in other regions, of upper Cambrian, of some
horizons of the Silurian, of lower Carboniferous, and of the Coal Measures.
From time to time individual forms, apparently indicative of a Devonian
age, have been found ; but in every case a more exhaustive examina-
tion of the locality has shown their association to be overwhelmingly Car-
boniferous or Silurian. The Devonian, therefore, seems to be wanting in
the Rocky Mountain regiou, as it has thus far been found to be in New Mexico,
Texas, Arkansas, and the Black Hills. To account for its absence in the
latter region, Mr. W. O. Crosby * has advanced the ingenious theory that,
in the cycle of deposition succeeding the Cambrian, the ocean had in De-
vonian time reached the abyssal depth at which, according to Murray, sedi-
mentation is no longer possible. While I must admit that evidence of shal-
low-water deposition is less conclusive in this interval than in those which
succeeded, and that portions of the Colorado islands were then submerged
which were not subjected to sedimentation during the succeeding intervals, I am
unable to accept this explanation for the Rocky Mountain region, and am
more inclined to attribute the absence of Devonian to a partial recession of the
ocean. The direct evidence of such recession is, it must be confessed, as yet
very slight, being limited to an unconformity by erosion between Silurian
and Carboniferous, observed in a single locality only,| and to the existence
of a thin and not always persistent sandstone between Silurian and Carbon-
iferous limestones.

This supposition corresponds better with the course of events on the east-
ern continent as recently traced out by Prof. J. D. Dana.j The break
which he shows to exist at the close of the Lower Silurian does not corre-
spond exactly in geological succession with the gap which appears to exist
in the Rocky Mountain region ; but the exact position of this gap in the
geological column is not yet determined. It is quite possible, moreover, that
the elevation of laud may not have been strictly contemporaneous in both
continents, and that the succeeding subsidence which allowed the reoccupa-
tion of the region by oceau waters may have proceeded more rapidly in the
one than in the other.

Early Paleozoic Land.

The laud areas that existed during this time, or rather the degrees to which
the present elevated regions were submerged so as to admit of sedimentation,
were somewhat as follows :

Colorado Island. — At the north the Laramie hills extension of the Colo-
rado range was submerged beyond the state line, and the shore-line extended

* Proe. Bos. Soe. Nat. Hist., vol. XXIII, March, 1S88.
t Monographs U. S. Geol. Survey, No. XII, 1886, p. 50.
X Bull. Geol. Soc. Am., vol. I, 1889, p. 36.

260 S. r. EMMONS — OROGRAPHU MOVEMENTS.

continuously along the flanks of the Medicine How range and across its ex-
tremity i" the Park range, but the ocean waters did not penetrate the North
and Middle parks which, up to post-Cretaceous time, formed a single con-
nected valley. On the east the shore-line probably reached higher and fur-
ther westward than the present hogbacks. Pike's peak stood out as a promon-
tory, or possibly as an island, the shore-line extending across the ridge to the
north of it into the bay now occupied by Manitou park, while to the south-
west the wato ra of the Canon City bay covered Webster park and portions
of the ridge through which the Royal gorge of the Arkansas is now cut, and
northwestward may have penetrated the South park depression. The main
connection of South park with the ocean was, however, from the northwest
around the northern point of the Sawatch uplift and across what is now the
northern portion of the Mosquito range.

Further north the western shore of the Colorado island was formed by the
l'aik ran-'-. BO that its general outline was triangular with apex toward the
south and its width about 1<>I) miles at the broadesl part.

s watch Island. — To the west of the South Park hay was the Sawatch
island, which included the west flanks of the present Mosquito range and the
upper valley of the Arkansas. The area of its present Archaean exposures
within the fringing reejf of Cambrian quartzites is about I'M) by 30 miles.
It was undoubtedly smaller at the time when these were deposited, hut their
outline probably preserves the general shape <>[' the original island, as they
resist erosion even better than the Aichaan rocks.

Southern Areas. - -With regard to the southern portion of the region, ii i.-
di (lieu It to reconstruct the probable distribution of land ami sea at this lime,
partly on account of the uncertainty with regard to the outlines given on
the Harden map, and partly because observers have not hitherto discrim-
inated between upper and lower Carboniferous horizons.

South of the latitude of < tanoa < 'ity and of the southern end of the Sawatch
i.-laml, the only region where the lower Palaeozoic rock- can with certainty be
-aid to have been deposited is ill the western portion of the San Juan mount-
ain-. AJong the Sangre de( !risto range the conglomerate series of the upper
Carboniferous is known to rest upon the Archaean in many places, and at the
southern end of this uplift Stevenson found lower beds which may belong to
the earlier series ; but in the presenl state of our knowledge of the Carbonif-
erous fauna of the R icky Mountain region the palseontologic&l evidence is

not decisive. By analogy it would seem probable that the two exposures
of Carboniferous on the , ;asl flanks of the Wet mountain- belong to the
lower series. On the other hand, in the outlying regions of the [Jncom-
pahgre plateau, in western Colorado south of the Grand river, and at the
Xuni and Naciinieiito mountains in northern New Mexico, upper Carbon if-
i roua beds rest directly upon tin- Archaean, which U in bo tar an evidence of

PALEOZOIC LAND AREAS. 261

land areas there during Palaeozoic time. As will be seen later, the eleva-
tion which accompanied an orographic movement did not affect the whole
area uniformly, but some regions were raised more than others, and indeed
there is some evidence to prove that some portions of the area Avere actu-
ally depressed while others were being raised. In a general way, therefore,
it may be said of the southern area that the distribution of land areas was
probably somewhat more widely spaced than in later times, and that inte-
rior depressions existed that were afterwards raised above ocean level, and
even became parts of prominent mountain masses as the outlying land-
masses were depressed.

The Late Palaeozoic Movement.

The existence of land areas toward the close of Palaeozoic time has been
frequently suspected by western geologists from the evidence of shallow
water and shore-line conditions in the beds which have been considered upon
somewhat meager and often conflicting palreontological evidence to belong
in different localities to the upper Carboniferous, Permian, or Trias ; but, so
far as I know, no actual unconformity has hitherto been observed. In the
summer of 1882 I first noticed what seemed conclusive evidence of the exist-
ence of such an unconformity in the Elk mountains, but it was not until
two years later that actual field work with my assistants, Messrs. Cross and
Eldridge, enabled me to fix its horizon as in the middle or upper part of the
Carboniferous.* Since that time I have found such corroborative evidence
of its existence in various parts of the Rocky Mountains as justifies the con-
clusion that a general orographic movement took place throughout this re-
gion, whose effects may probably be found to have been felt beyond it. It
is a movement that is in many ways difficult to define. Firstly, on account
of the wide range of most of the abundant molluscan species which are
found in Carboniferous beds, owing to which palreontological evidence by
itself is thus far of but little value in determining the relative position of
any beds except those at the two extremities of the series. Further, because
the dynamic disturbances that accompanied the movement were very un-
equally distributed, and their effects are to be observed, as a rule, only in
regions which were again violently disturbed during the succeeding move-
ment, where they were consequently much obscured. Its determination as
occurring in middle or late Carboniferous time has, therefore, necessarily
been founded mainly on the stratigraphical relations and lithological
character of the beds.

That it was not earlier than middle Carboniferous is proved by the finding

* A notice of this, and of the Jurassic unconformity observed in the same region, was published
in the Sixth Annual Report of the I >ireetor of the U. S. fteol. Survey, 1885, p. 64.

262 S. I. RMMON! OROGRAPHIC MOVEMENTS.

■ it' Coal Measure fossils in the limestone pebbles that in s e regions form a

characteristic feature of the conglomerates deposited immediately alter the
movement. < >n the other hand, the thickness of beds deposited after the
movement, presumably of < larboniferous age, is far greater than that of those
beds deposited before it: but as these are of extremely coarse material,
evidently deposited during the rapid abrasion of high land-masses in com*
paratively close proximity, il is evident thai the mere thickness of the deposil
is n<'t a very reliable time-gauge.

During this movemenl some ana- were uplifted and eroded in such a way
that the later sediments overlapped the upturned edges of the earlier beds.
In others, tor instance around the shore-line of the Sawatch, the elevation
was of such a nature that the succeeding sediments were deposited in perfect
conformity, and no evidence of erosion lias been detected between the two
series of )>v<\<. though land plants and limited developments of coal or of
bituminous shahs are found at certain horizons.

Perhaps the most remarkable feature of the sedimentation which followed
the movement was the great thickness of very coarse conglomerate alongthe
present Elk mountain ami Sangre de Cristo ranges, reaching a thickness of
3,000 to 6,000 feet, which are not found at all on the east front of the Col-
orado and Wet mountain ranges. In the Elk mountains the pebbles are
mostly of limestone, which are entirely wanting at corresponding horizons
along tin- adjoining Sawatch range. Iu the San- rede Cristo range they are
mostly of gneiss and granite, with some limestone pebbles; the fragments of
Archaean rock- in the beds opposite the Wet Mountain valley are often as
much as 25 or even 50 feet ill diameter, and must either have dropped from
adjoining steep cliffs or have been carried out into the sea by ice. To
account for the formation and present stratigraphical relations of the Klk
mountain conglomerates it is necessary to assume that during the move-
ment a land area was uplifted to the south of that region, from which the
earlier Palaeozoic beds were mostly denuded, and whose original outlines
<>r area can no longer l>e determined.

The sediments that were deposited between this and the succeeding move-
ment near the close of the Jura were largely conglomerates, with a few mud
shah- and occasional thin beds of limestone. The Triassic "Red Beds"
near the top contain finer grained sandstones and some clays. Gypsum is

found locally developed at various horizon-.

In most of the beds deposited during this interval it has hitherto been im-
possible, in the absence of decisive palseontological evidence, to determine
how much <d' the entire series is represented. < mly the < iarboniferous beds

have been found to contain molluscan remain-, and the-,- are wanting in the

coarser grits and conglomerates. The evidence afforded by plant life has
thus far proved to In- somewhat meager and uncertain. In outlining geolog-

CLOSING PALEOZOIC MOVEMENTS. 263

ica] divisions on maps, therefore, too much reliance has necessarily been
placed on distinctions derived from the character of the sediments. While
that of the upper part of the Trias seems to be persistent over this and the
adjoining regions, the earlier sediments only show a general prevalence of con-
ditions of rapid abrasion and shallow-water conditions. Whether the Permian
beds, recognized in the Wasatch and Grand Canon regions on the one side
and along the borders of the eastern continent and in Texas on the other,
are represented here seems still uncertain. Plants of Permian facies have
been found, but they are often associated with a Carboniferous fauna. It is
possible that the general elevation, which the shallow-water conditions imply,
may have shut out the ocean waters during part of this period ; this is
rendered probable by the evidence of a movement at the close of the Per-
mian said to exist in other regions. The erosion which took place at the
close of the next succeeding movement is known to have been locally very
great in the Rocky Mountains. Whether the marine Jura, as developed to
the west and north, was deposited in this region and has in great measure
been eroded away, or whether its elevation was such that the early Jurassic
■* seas did not penetrate it, remains yet to be determined by future investiga-
tion. The only fact bearing upon this point is the observation by Mr. G. H.
Eldridge of an unconformity by erosion between the Trias and fresh- water
Jura along the foothills of the Colorado range near Denver.

Late Palaeozoic Land.

The outlines of the various land areas during the subsidence that fol-
lowed this movement were, as far as can now be determined, somewhat as

follows :

Colorado Island. — Along the eastern and northern shores of the Colorado

island, no upper Carboniferous beds corresponding to the conglomerates of the

Elk and Sangre de Cristo mountains have yet been recognized. The Triassic

" Red Beds " now rest directly on an Archaean or lower Palaeozoic basement,

as the case may be. Hence it may be assumed that during upper Carbon.

iferous time these shore-lines were still above water, and that the subsidence

had continued into Triassic time, so that what upper Carboniferous sediments

might have been deposited were overlapped and buried from sight by those

of the Trias. Triassic sediments invaded the depression of North park, but

apparently did not extend far into the Middle park.

South park was connected with the western ocean across the northern end of

the Mosquito range, as in early Palaeozoic time, and received a complete and

regular series of sediments. On the south the bays at Manitou and Canon

City were probably not so deeply invaded as in early Paheozoic time, nor is

there any evidence that upper Carboniferous or Triassic sediments ever oc-

XXXV— Bull. Geol. Soc. Am., Vol. 1, 1889.

264 -. I. EMMONS — OROGRAPHIC MOVEMENTS.

copied Webster park or Parkdale valley; if they < 1 i < 1 they have since been
very completely eroded away.

Park range was probably isolated and formed an island, which was not
connected with the Colorado island. Along its present shore-lines the upper
Carboniferous beds are now so completely masked by subsequent Mesozoic
sediments that their original extent cannot be determined. They are dis-
closed, however, by the more recent uplift and erosion of the While river
plateau to the west, over which area sedimentation apparently went on con-
tinuously without leaving any very marked evidence of the movement.

Sawatch Island. — Around the immediate shores of the Sawatch island sedi-
mentation apparently went on in unbroken continuity up to the time of the
Jurassic movement, no evidence having yet been detected in the remarkably
regular series of bed- that now surround it of any dynamic disturbance. The
character of these sediments Bhows, however, that shallow-water conditions
prevailed from the middle of the Carboniferous to the close of the Trias,
some small deposits of coal having been locally formed, and beds of coarse
conglomerates, containing pebbles that must have been derived from Bome
neighboring land-mass of Archaean rocks, constituting a very considerable
proportion of the section exposed. Alternating with these are occasional
bed- of limestone, which are of so frequent occurrence and have so little per-
sistence that they cannot be assumed to necessarily imply deep-water depo-
sition, but rather local changes in conditions of sedimentation.

On the immediate western flanks of the Sawatch range, in the Elk mount-
ain-, were deposited at this time a thickness of not less than three thousand
feel of reddish conglomerates, characterized by a great abundance of lime-

ne pebbles associated with those of Archaean rocks, of which no litholog-
ical correspondents are found in the beds encircling the Sawatch uplift.
These beds have been deposited over eroded surfaces of previously folded
Palaeozoic beds, and Carboniferous fossils have been found in some of the
pebbles. Theirmaterial must have been derived, therefore, from the abrasion

- >me land-mass formed by the upheaval during this movement of an area
over which sedimentation had been going on during early Palaeozoic time.
They could not have come from the erosion of the Sawatch island, otherwise
the time correspondents of these beds around thai island would have con-
tained limestone pebbles also*

A careful consideration of the present stratigraphieal conditions of the

. ion -how- that this la ml -ma— inii-t have existed somewhere to the south
of the Klk mountains in the region about the head of the Gunnison valley
and possibly extended towards the northern end of the San Luis park. This

land-m. I— may have been connected with the BOUthweSl end of the Sawatch

island.
At the southeast end of this island is a Bhnilar unusual thickni irse

CONGLOMERATES OF WET MOUNTAIN. 265

sandstones and conglomerates of prevailing red color, exposed by the erosion
of the Arkansas river after it assumes its eastward course, which occupy a
corresponding stratigraphical horizon, without, however, showing any evi-
dence of unconformity with the beds below.

Wet Mountain Island. — The Saugrede Cristo mountains, from the Arkan-
sas river southeastward to the head of Huerfano park, must have formed the
western shore of the Wet Mountain island at this time, their relative posi-
tions as mountain and valley having been then the reverse of those which
exist nowr. This range opposite Silver Cliff is largely made up of an immense
thickness of conglomerate whose pebbles, of all varieties of Archaean rock,
cannot have suffered any very prolonged attrition, for they not only con-
sist of relatively soft material, but are sub-angular and often in immense
blocks over 25 feet in diameter which could not have been carried very far.

It seems probable that these conglomerates extend the entire length of the
range, since they have been observed by Stevenson on its eastern flanks, ex-
tending beyond the state line into New Mexico, where they contain limestone
pebbles associated with those of Archaean rocks. He gives them an aggre-
gate thickness at one point of about 6,000 feet.

It is a question whether the material of which they were composed was
derived from the Wet Mountain island or from some land-mass to the west-
ward which has now disappeared. The fact that on the east flanks of the
Wet Mountain island no beds at all corresponding to them in thickness or
coarseness of material have been found, would favor the latter conclusion.

The section at Canon City shows a thin limestone conglomerate or breccia,
made up of slightly rounded fragments, immediately and unconformably
overlying the lower Palaeozoic beds, and succeeded by a few hundred feet of
beds mostly of reddish arkose material with a few limestone pebbles near the
base. The characteristic red sandstones of the Trias have either been eroded
away or are overlapped and concealed by the unconformable Jura-Dakota
beds. Two exposures of Triassic beds are indicated on the Hayden map
south of this point along the eastern flanks of the Wet Mountain range.
Elsewhere they have been overlapped by the unconformable Jura-Dakota
series. In like manner, south of Huerfano park, along the east front of the
Sangre de Cristo range, the Jura-Dakota beds abut directly against Archaean
or Carboniferous rocks, and no Triassic beds have been recognized, except
near its southern extremity.

San Juan Island. — In the San Juan region, elevation and erosion is shown
to have taken place by the fact that on its northern flanks a slight angular
unconformity is observed between the lower Palaeozoic series and the coarse
grits, sandstones and shales that were deposited during the later Carbon-
iferous. This discrepancy of angle was not observed on the southern slopes
of the mountains along the Animas canon, but of the areas represented there

266 S. K. EMMONS — OROGRAPHIC MOVEMENTS.

on the Hayden map as Devonian and Carboniferous the lower part is known
to be Silurian and the upper part Triassic. If the upper Carboniferous is
not exposed it must have been overlapped, as on the eastern shores of the
Colorado island, by the succeeding Triassic sediments.

In the wide area of the Uncompahgre plateau, to the west and northwest,
Triassic beds arc well developed, and the Carboniferous exposures represented
as resting directly on the Archaean are considered by Dr.Peale to belong to
the upper portion of this series. It would seem probable that these and the
similarly outlying regions of the Zuni plateau and the Nacimiento mountains
were island elevations in the early Palaeozoic seas over which no sediments
were deposited, and that after the late Palaeozoic movement they were de-
pressed below the sea level, since recorded observations seem to show that
continuous sedimentation went on over them from Carboniferous into Meso-
zoic time.

< 'onclvMons mul Correlations. — Without a special examination of the region
with this object in view, it is difficult to make any satisfactory conjectures
as to whether the < !arboniferous beds at a given locality belong to those de-
posited before or after this movement, or whether both are represented. From
the present evidence it would appear that in the middle portion only of this
ion was the movement accompanied by any marked dynamic disturb-
ances, and that elsewhere it was in the nature of a parallel transgression.

Again, while in the interior the aggregate thickness of the Palaeozoic beds
reaches from five to seven thousand feet, along the east Hanks of the Colo-
rado range, in the Laramie hills of Wyoming and the Black Hills of Dakota
their exposures rarely show more than seven or eight hundred feet of beds.
While it is certain that in the latter regions the lower Palaeozoic bed- are
represented, no evidence has yet been presented to show that upper Carbonif-
i rows horizons are exposed there; but the Triassic "Red Beds" are in most
cases characteristically developed. Palseontologically, Coal Measure forms,
which are abundant throughout the Carboniferous beds, cannot be consid-
ered characteristic of either Beries, and it is only those having a Permian
facie* thai afford definite evidence of the existence of the upper ( larboniferous
beds. On the other hand, in the Rocky Mountain region the lithological
characteristics, that furtherwesl serve to distinguish the beds carrying a Per-
mian fauna from the Carboniferous on the one hand and from the Trias on
the other, are wanting ; and there arc very con -idem I do thickni sses of beds
about which it can only be Baid that they were deposited Bomewhere in the
interval of time between the Carboniferous and Jurassic movements. What-
r r n : i \ be predicated in regard to the orographical history of this interval
i- nec< ssarily based upon data which are liable to be modified in the future,
and hence are very conjectural. It is, that the elevation accompanying the
movement was followed by an irregular subsidence, which was more pro

APPALACHIAN AND CORDILLERAN MOVEMENTS CORRELATED. 26'J

nounced in the interior region, but in the outlying region was followed by-
further subsidence in Triassic time, as a result of which the earlier beds were
overlapped to such an extent by the Triassic sandstones that they have rarely
been exposed by later movements or erosion.

In the Wasatch and Uinta regions, the upper Carboniferous and Permian
are undoubtedly represented. If I am right in considering that only the upper
members of the Carboniferous are represented in the Uinta range, it would
become probable that the erosion observed by Powell iu the canon of Green
river on the beds underlying the Carboniferous was produced during the eleva-
tion that accompanied this movement.

With regard to the broader and more continental elevations, the fact that
over the Palaeozoic continent of Utah and Nevada, as well as over the great
Appalachian continent, not only Mesozoic but also Permian beds are wanting,
would indicate an alternate movement between those regions and the Rocky
Mountains — that is, that during the Carboniferous elevation of the latter these
still remained below the level of sedimentation, though shallow-water condi-
tions prevailed to a certain extent, but that, while in the Rocky Mountain
region subsidence continued into the Trias, the continents on either side reached
a permanent elevation at the close of the Carboniferous time which was so far
maintained that the waters of the ocean never again invaded them.

A similar condition, according to present evidence, would seem to have
obtained in northern Mexico ; for Dr. White* considers that south of the 34th
parallel no Trias or Jura exists, but that the marine lower Cretaceous (which
also includes possible representatives of the Atlantosaurus beds) rests directly
upon the Carboniferous.

The Jurassic Movement.

The succeeding orographic movement of the region, which was even more
widespread and more marked iu its effects, has been designated the Jurassic
movement, because the first beds deposited after it were those containing the
vertebrate fauna determined by Professor Marsh to be of late Jurassic age,
and called by him " Atlantosaurus beds." A somewhat meagre fresh-water
molluscan fauna, considered by Dr. White as also of late Jurassic age, has
been found by him in the Atlantosaurus beds of the eastern flanks of the
mountains, and by Mr. Eldridge in beds corresponding stratigraphically and
lithologically with these on the west flanks in the Elk mountain region, where
the dynamical effects of the movement are most marked and have been most
carefully studied. The beds which in the Rocky Mountain region are char-
acterized by this fresh-water Jurassic fauna are generally very thin, contain
as a rule but scanty remains of organic life, and want the persistence and

* Am. Journal Sci., 3d ser., Vol. XXXV1I1, 1889, p. 440.

268 S. I. EMMONS — OROGRAPHIC MOVEMENTS.

peculiar lithological composition of the overlying Dakota Cretaceous which
renders that formation one of the most readily recognizable of all the Meso-
zoic series. As actual observation has shown that in some cases the earlier
loeists included these beds in their Dakota formation, the term Jura-
Dakota bas been used in this paper to designate the beds first deposited after
the movement, in order to distinguish them from the marine Jurassic beds of
other regions, which were deposited before them ; without, however, implying
thereby, in localities that have not been personally observed, more than the
probability of tin' existence of the freshwater beds.

The evidence of this movement thus far obtained is of two kinds : First,
thai derived from personal observation in regions of violent disturbance,
where, during the elevation produced by the movement, considerable areas
had been uplifted by folding, often combined with faulting. and greal thick-
nesses of rocks, sometimes thousands of feet, bad heen eroded away ; and where,
during the subsequenl depression, dura-Dakota beds had been deposited
upon these eroded surfaces. The most marked evidences of such movements
are found in the Elk mountain region, where, along a single line of strike,
the dura-Dakota beds upturned during the post-Cretaceous movement
are seen to rest alternately and in repeated successions upon beds of all the
horizon.- from Archaean up to Trias, and to rest upon the latter in the middle
of the region in perfect conformity. Other violently disturbed region- ob-
served are the northern Mosquito range, the eastern flanks of the mount-
ains mar ( "anon ( 'ity. and tin' northern portion of the San Juan mountain-.

'flu- second class of evidence is the tint indicated by geological maps that
the Dakota Cretaceous, presumably Jura-Dakota, rests directly upon Ar-
chaean or Carboniferous at very many points throughout the region. In the
other portions uf the region, where the dura-Dakota is represented as resting
■ in the Trias, unconformity by erosion has in a few cases been detected.

The most persistent and readily recognizable horizon of Mesozoic age in
the Rocky Mountains is the Dakota Cretaceous. It is prevailingly a sand-
stone with a characteristic basal conglomerate, the sand-tone becoming
readily quartzitic, even when adjoining Bauds tones are not altered, so t hat its
upturned strata, owing to their resisting nature, always stand out promi-
nently, 'fin- fresh- water" dura below it, bo far as it ha- been studied, gener-
ally ha- a sandstone at or near its ba.-e which is softer and frequently cr<
bedded to a remarkable degree. Between these t\\" sandstones i- a series of
-hah- ami clays, cairs ing a certain amount of limestone, which in some plai
forme a continuous bed, and at others occurs in lenticular bodies in the shall
The shales are frequently variegate. 1 in color, and bedsof gypsum are some-
times found.

The Cretaceous beds above the Dakota consist, in the Fori lien tun group,
largely of .lark .-hah-.-, with a slighl development of limestone, often bitumi-

THE JURASSIC FAUNA. 269

nous ; in the Niobrara, light- colored limestones predominate over the shaly
members, becoming chalks in the deeper portions of the seas. The Fort
Pierre is a great thickness of gray shales mostly argillaceous, while in the
Fox Hills the shales become more arenaceous and pass into sandstones at
the top of the formation. The Laramie is mainly sandstone in the enclosed
sea-basins near large land-masses, with an increasing admixture of shales
as the distance from these land-masses increases.

An abundant and characteristic verterbrate fauna has been discovered
in the Jurassic beds at Como lake, in Wyoming, and at Canon City and
Morrison, in Colorado ; a somewhat meager fresh-water molluscan fauna is
associated with this in the two former localities, and some of the same forms
occur at a corresponding horizon in the Elk mountains of Colorado. They
are also reported from the Black Hills of Dakota and somewhat doubtfully
from the Green River basin of Wyoming.

The Dakota formation carries an abundant flora which includes many de-
ciduous plants, but in the Rocky Mountain region no marine forms have
yet been found in it. The faunse of the other horizons of the Cretaceous up
to the Fox Hills are all marine, and in the Rocky Mountain region the change
from the marine forms in this horizon to brackish-water forms in the Lara-
mie is most marked and distinct.

Jurassic Land.

The more detailed and local effects of the Jurassic movement upon the
various land ai'eas under discussion were, so far as present facts afford any
indication, somewhat as follows :

Colorado Island. — The general outline of Colorado island as determined in
early Palaeozoic time had thus far not been essentially changed. A general
encroachment of the ocean upon its shores had been in progress, whose effects
were more marked in the shallow bay-like depressions at its northern
and southern extremities than along its steeper east and west shore-lines.
The present areas of the North and Middle parks then formed a single
depression, the present dividing line between them having been formed in
post-Cretaceous times. North park had already been invaded by ocean sedi-
ments, and after the Jurassic movement further subsidence took place, so
that the sea extended through the Middle park connecting with the waters
occupying South park, and also across the Gore mountains westward to the
Colorado plateau waters.

The relative distribution of the marine and fresh-water Jura is as yet but
imperfectly known. To the west of the Laramie plains, throughout the
Uinta and Wasatch regions and in eastern Idaho, the marine Jura is well
developed, but as yet no fresh-water beds have been recognized ; while at the
Como lake anticlinal both marine and fresh-water Jura are found.

•_'7<l S. I'. EMMON OROGRAPHIC MOVEMENTS.

( )n tin' eastern shores of the < lolorado island no evidence of the existence
of marine Jura has been found south of the Latitude of the Laramie plains.
The fresh-water beds rest directly upon the Triassic without any apparent
discrepancy of angle. The thickness of" Red Beds" assigned to the latter
age varies very greatly from poinl to point. This would naturally be ex-
plained by the unequal erosion of these beds during their elevation ; but
where the evidence of sub-aerial erosion seems insufficient it might be partly
accounted for in the case of beds, which like these bear internal evidence of
having been deposited in strong along-shore currents, by the existence of
broad, ridge-like corrugations in the sea bottom extending out at an angle to
the shore-line, on the crests of which the accumulation of sediment would be
much less than in the adjoining depressions. There is sonic evidence of the
formation of such corrugations during the movement of elevation at various
points along the eastern front of the mountains, though it cannot always be
definitely assigned to this period.

In the Canon city region there is evidence of considerable elevation and
erosion during the movement, followed by a subsidence which admitted the
Jura-Dakota waters to Webster park and to the valley of Parkdale at the
west end of the Royal gorge. How far these waters extended to the
northwest towards the South park depression has not yet been determined.
Near Canon City the discordance of strike between the now sharply up-
turned Jura-Dakota and the underlying beds is most marked, and points to
a very considerable disturbance and erosion of the latter before the former
were deposited. As the immediately underlying beds are here very Bofl and
easily eroded, the actual contact and any discrepancy of dip-angle that may
exist with these intermediate beds, whether Carboniferous or Triassic in B
has not been observed, due dura Dakota beds rest at different points,
however, on these, on the early Palaeozoic beds, or on the Archaean; and
their discrepancy of angle with the two latter is very marked.

The western shore-line of the Colorado island is more difficult to define
than the eastern, since it has been more extensively faulted and eroded in
post-Me80zoic tim< -

It is noticeable that the northwest structural line along which the greatest

disturbance ha- taken place passes thomgh the ("anon City region just de-

ribed. The most notable effect of the orographic movement along this line
was the cutting off of the previously existing connection between the South

park bay ami the western ocean of the Plateau region, an effect which ha- a

more than local significance. It was produced by an uplift of the northern
P irtion of the Mosquito range and of the (; lie mountains on the east side
of the Mosquito fault, which has been traced northward along the western
crest of the Mosquito range and t hence northwestward along the wesl tlanks
<»f the Gore mountains to within fifteen or twenty mile- of the Grand

THE S-FOLD A PREVAILING STRUCTURAL TYPE. 271

river. The character of this uplift was not the simple uptilting of a block of
the earth's crust into a monocline, as has been shown to be the prevailing
character of movement in the Plateau region by the geologists who have
worked there, nor the vertical upthrust of a block bounded by two lines of
faults, which one of them has propounded as the type of the uplift of the
Park province or Rocky Mountain region. It was the result of compress-
ive folding, producing a fracturing or faulting along the steeper side of a
one-sided or S-fold, which is the prevailing structural type in this region.
From the northern end of the Mosquito range and the Gore mountains,
thus raised above the ocean level, the sedimentary beds from Cambrian up
to Triassic, which had been deposited upon them around the northern end of
the Sawatch uplift, were almost entirely eroded away, a few patches only
remaining on the crest and steeper western side of the uplift to prove the
character of the fold. Around the eastern and northern flanks of this
uplift, from the waters which during the succeeding depression entered the
Middle park, whether from the north through North park or from the west
across the Park range north of the Gore mountains, the Jura-Dakota beds
were deposited directly upon the denuded Archaean ; west of the Park range
they stretched continuously across the fault line and rested in apparent con-
formity upon the Triassic beds, north of Eagle river and west of the fault
line, which had escaped erosion.

This view of the structure of the region, which involves important modi-
fications in the structural history of the Mosquito range given in my mono-
graph upon the Leadville region, has naturally been adopted with extreme
reluctance and under the influence of gradually accumulating evidence in its
favor, combined with an inability to explain the known geological occur-
rences in any other way. In that monograph* I assumed, in the absence
of any direct evidence of dynamic movements previous to the close of the
Cretaceous, that the folding and faulting of the Mosquito range was probably
post-Cretaceous, although I foresaw the possibility and even probability that
further investigation might lead to a modification of this view. The age of
the porphyries, which were folded and faulted with the enclosing sedimentary
beds and hence were necessarily older than the dynamic movement, I as-
sumed to be late Cretaceous, since similar rocks are found in other parts of
the Rocky Mountains cutting through the latest Cretaceous formations.

According to my present view a part at least of the uplift of the Mosquito
range must have occurred in Jurassic time, though I still think that the
mountains were further disturbed and uplifted during the great post-Creta-
ceous movement. The greater part, if not all, of the porphyries must, how-
ever, have been intruded before the Jurassic movement, and the original

* 1886, pp. 23 and 31.
XXXVI— Bull. Geol. Soc. Am.. Vol. 1, 1889.

272 S. P. EMMONS — OROGRAPHIC MOVEMENTS.

ore-deposition of the region must also be assigned to a period anterior to
that movement.*

North of the Gore mountains, the Park range opposite Middle park was
submerged, for a distance not yet determined, during the Jura-Dakota sub-
sidence: hut the northern part of the range remained above water, and the
Grand Encampment mountains may, as already suggested, have formed
pari of the Bame island with the Medicine Bow range. Tertiary and Recent
deposits now mask the ilanks of these mountain masses to such an extent
that all that can he said with certainty is that the Cretaceous deposits
wrapped around them without apparently extending up the present valley
of the North Platte as far a.- the North park.

11'-/ Mountain and Sangre de Cristo Island*. — During or possibly even
before the Jurassic elevation, these two islands were consolidated into a .-ingle
land-mass, which may now be called the Sangre de Cristo island. If any
Triassic sediments had been deposited between them upon the upper Car-
boniferous they had been entirely eroded away. The eastern shore-line of
this land-mass had the .same general outline as the mountain front of tO-day,
with a reentering bay at Huerfano park extending somewhat further into
Wei Mountain valley than it does at present, and probably some submerged
ridges making out at an angle from this shoredine. Either from unequal
deposition over these ridges, as explained above, or on account of an unequal
erosion of the Triassic beds, the latter are only found at widely separated
intervals along the flanks of the Wet mountain range, and are apparently
altogether wanting along the Sangre de ( Jristo range, except possibly at its
southern end, in New Mexico. The Jura-Dakota beds consequently rest for
the most part upon upper Carboniferous or Archaean rock- at different
points along the shore line.

The western limits of the Sangre de Cristo island may never be accurately
determined, for the reason that on this side tire basement rock- are now com-
pletely concealed beneath the recenl alluvial deposits of the San Luis valley
and the immense flowsof igneous rocks Lo the north and wesl of this de-
pression. From observed conditions in the present known exposures of
Mesozoic beds in this region, however, il seems probable that it formed a
continuous land-ma-- with the San Juan uplift, and that the dura- 1 >akota
,-hoie line bent around the southern end of the present Sangre <le Cristo

• to Bay tbat a local it) of critical importance with reference to this movement ha*

not, i can learn, ever been visited by any geologist now living. This lathe northwest

i mountains where the Mosquito fault, according to the Indications of the Hayden

Map, aft* i eparating the Triass the wesl from the Archaean on the east, Is cut ofl .'it right an

by Jura-Dakota bi ten Ins; acro»N Its path and resting on either formation. The iceologTcal

outlines there given, however, were laid down by the hand "i Mr \ R Mai v Ine, who surveyed i in-

lon.but whose untimely deatl u i written up his field notes i"r puhlfca-

curacy of Mr. Marvlne's work that I have

no hesitation in accepting I lal correctni lines, whioh are partially confiri I

by tl ' Mr. Holi , who crossed the fault a few miles south of this point, and by

elf and n ants, who lun- I minutel) tbe Mosquito fault northward to

within twenty miles <•! this point.

EROSION OF JURASSIC LAND. 273

range not far north of Santa Fe, and thence ran northwestward across the
Rio Grande valley, westward around the head of the present basin of the
San Juan river, and again northward across the west flanks of the San
Juan mountains at the head of the Dolores and San Miguel rivers, turning
eastward again across the heads of the Uncoinpahgre and other tributaries
of the Gunnison.

It is possible that the northwestern extension of the Jurassic land-mass
connected with the southern end of the Sawatch island, for all Mesozoic
sediments are now wanting between the Arkansas and Gunnison rivers.

The San Juan area was, during the period of elevation, uplifted and eroded
in such a manner that along the northwestern flanks the Jura-Dakota beds,
which were deposited during the succeeding subsidence, not only rested in
distinct angular unconformity upon the edges of the Triassic and upper
Carboniferous beds, but overlapped in places onto the underlying lower
Palaeozoic series. On the southern flanks, however, the angular uncon-
formity is not readily apparent, but the Triassic beds apparently thin out
and finally disappear to the eastward of the Animas canon, having probably
been eroded away.

Sawatch Island. — The area of the Sawatch island was very largely increased
during this movement, not only by the recession of the surrounding seas, but
by the actual addition of adjoining areas by dynamic movements. That oil
its northern extremity has already been mentioned. The uplift of the
northern portion of the Mosquito range and of the Gore mountains extended
its area to the borders of the Middle park. A thickness of not less than
6,000 feet of beds has been eroded from the crest of the Mosquito range, and,
although it cannot be assumed that this was entirely accomplished during
the period of elevation, it is evident that enough time must have elapsed to
allow of the complete denudation of the northeastern flanks of the Mosquito
range where Jura-Dakota beds now rest directly upon the Arcluean.

On the west side of the Sawatch there is more definite evidence of the
amount of erosion that must have taken place after the upheaval that
accompanied this movement. It is in the Elk mountains that this record is
now found — a region that was so intensely disturbed in the post-Cretaceous
movement that it is now impossible to correctly outliue the land area that
was added to the Sawatch island, or even to say with certainty that the por-
tions of this region that must have been above water were actually connected
with it. It is probable, however, that a ridge extended eastward from the
region at the head of the valley of Roaring fork to Treasury mountain, and
that another extended southward toward the ancient land-mass at the head
of the Gunnison valley, from each of which the Triassic beds, and in some
cases a large portion of the upper Carboniferous, were eroded. The best
localities for studying the effects of this erosion and the unconformity of

274 S. I. EMMONS — OROGRAPHIC MOVEMENTS.

the Jura-Dakota beds with those on which they rest are along the western
thinks of the mountains in the presenl valleys of Slate and East rivers, which
flow southeast, and of Rock creek, which flows northwest. A.long th
valleys the beds are now upturned at a sharp angle and often inverted, and
it is by discrepancy in strike alone that the unconformity is shown. Pro-
ding northwestward from the Gunnison river up the former valleys, the
Jura-Dakota beds are first found resting directly upon the Archaean : then
<>n tin- east side of the valley, neglecting minor irregularities due to local
folds and faults, they resl successively on upper Cambrian, Silurian, lower
Carboniferous, upper Carboniferous, and. finally, at Copper creek, opposite
the town of Gothic, mar the head of East river, they rot in apparent angular
conformity upon the Triassic"Red Beds." Following the strike further
northwestward, the Jura-Dakota contact descends again in horizon, resting
upon upper ( larboniferous beds and. around the remarkable Archaean protru-
sion of Treasury mountain, upon lower Palaeozoic Limestones, now changed to
most beautifully variegated marbles. Still further north along the valley of
Rock creek, the upper Carboniferous and Trias come successively up to the
base of the Jura-] Dakota.

In the region along the Grand river and the White river plateau beyond
it. which has not been visited by the writer, no unconformity between the
Jura-Dakota and Trias is noted by the members of the Bayden survey,
though the outlines on their maps are such as to surest that evidence could
he found both of this and of the earlier movement if they were Studied to
this end.

Western l!'<ii<>n. — [n the broad area south of the Gunnison and Grand
rivers, which was a region of comparatively little disturbance in pre-Creta-
lus time, no evidence of unconformity was noted by the members of the
Bayden survej who visited it. The beds which they classed as lower
Dakota in the coloring of their map are, however, the lithological corre-
spondents of the Atlanto8auru& beds a- developed in the Elk mountain region ;
and Mr. Bolmes ha- recently Btated to me that he now considers them to

belong below the Dakota and to he probably of Jurassic age.

< )n the eastern shore line, at the base of the San Juan mountains, there is
a heavy littoral conglomerate and an evident unconformity at the base of
the Jura-Dakota, which ha- been noted also by Mr. K. ( '. Bills.* Whether
the limestone, which h< places below this unconformity and above the red
sandstones containing vertebrate and plant remains of Triassic age, should
be considered to represent the marine Jura of the Wasatch and (Jinta
mountain- i- somewhat uncertain, as no organic remain- have yet been dis-
covered in it.

1/ Newberry and Holm,- both failed to find any

km. Jour. Set., 3d wr., Vol. XIX, June, i

THE SOUTHEASTERN MESOZOIC DEPOSITS. 275

Jurassic beds represented in northern New Mexico, although Marcou in his
earlier explorations, coming to the region from the east and along a line not
visited by either of the others, found beds corresponding to what he had
considered as Jurassic in northern Texas. Newberry found Triassic plants
in reddish sandstones immediately beneath sandstones which he regarded as
Cretaceous, but it does not appear from his published accounts that their
relative position was such as to preclude the possibility of a slight uncon-
formity lid ween them.

Further south, in the Zufii mountains, Button found a considerable thick-
ness of sandstones above the " Red Beds" which he regarded as probable
representatives of the Jurassic of the Plateau region, although he obtained
no fossils from them.

To the eastward, in the region around the southern end of the Sangre de
Cristo range, Stevenson found the Dakota Cretaceous to have suddenly
thickened to 1,700 feet from the normal development of about 300 feet
which obtains with remarkable regularity from a few miles northward along
the whole front of the Colorado range, and this thickening seems to have
taken place below the sandstone generally recognized as characteristic of
the Dakota throughout the Rocky Mountain region. He, also, failed to
recognize the Jurassic of Marcou. New-berry, however, thinks to have
recognized representatives of the fresh-water Jurassic in northern New
Mexico *.

Texas and Arkansas. — Recent geological observations in Texas and west-
ern Arkansas show, according to Mr. R. T. HilLf that the marine Creta-
ceous beds of that region have been deposited along the southern base of an
uplift, as yet imperfectly known, of the Paheozoic rocks, extending from Ar-
kansas westward through Indian Territory and northern Texas, and south-
westward into New Mexico. It is not yet definitely known whether early
Mesozoic beds are involved in this uplift, so that its formation could be
correlated with the Jurassic movement in the Rocky Mountain region,
though certain facts render this probable.

The Cretaceous beds are divided by Mr. Hill into an upper and lower
series, divided by a land epoch marking a physical as well as a palseontolog-
ical break. The upper beds deposited since this break show a similar cycle
in the character of their sediments with the Cretaceous beds of the Rocky
Mountains, with which they are correlated by Mr. Hill, the Lower Cross-
Timber (Dakota) being a littoral formation, with basal conglomerate and
abundant plant remains. The succeeding beds indicate gradually deepening
waters culminating in the Rocky Comfort chalk (Niobrara), and showing
evidence of a shallowing sea in the upper series, which corresponds to the

*;Personal communication.

t.\m. Jour. Sci., 3d ser., Vol. XXXVIII, 1889, p. 282.

-,i> S. P. EMMON OROGRAPHIC MOVEMENTS.

I' \ Hills — representatives of the Laramie Dot yel haviug been definitely
recognized, possibly through having been eroded away.

Unconformably below these beds come a series of marine 1>«-«1> of lower
Cretaceous age, known as the Comanche Beries, which have been traced
through Texas southward into Mexico, the base of which is formed by the
Trinity beds, or Dinosaur .-amis, which resemble the AUantosaurus beds of
the Rocky Mountain region. These rest unconformably upon the underly-
ing beds, which in most cases thus far observed arc found to be of Carbonif-
erous ;i

N representatives of the Comanche beds have yet been found in the
Rocky Mountain region nor in the Plateau province; but from near the
international boundary, in about longitude 115°, the Canadian geologists
have traced a Beries of marine Cretaceous beds stretching northward into
British Columbia, known as the ECootanie beds, which are lower than the
Dakota Cretaceous. From the plant ami molluscan remains found in these
beds Mr. George M. Dawson* regards them as equivalents of the Comanche
series (though perhaps not reaching quite as far hack in geological time),
and of those developed on the Pacific coast in Queen Charlotte's island, and
considers that they were once connected with the latter north <>t' the 54th
parallel.

Th <ir>'ii Plains. — As early as 1877, Dr. Whitef called attention to the
probability of a post-Jurassic subsidence which carried the eastern shore-line
of the interior M - / lie ocean eastward across the < rreat Plains and permitted
the deposition of Dakota beds in central Iowa, which subsidence continued
through Fort Kenton and Niobrara times, causing a Btill further eastward
extension of the shore-line and a corresponding change in the character of
the sediment- from diallow to deep water.

Since that time evidence has Keen found at various point- throughout the
area of elevation, folding and erosion of the underlying beds previous to
this subsidence.

rn the Raton mountains, some sixty miles east of Trinidad, Cretaceous
lied- reel unconformably on steeply upturned Triassic -ami-tone-. North of
this, at Fort Lyons, on the Arkansas river, an artesian boring disclosed a
tit thickness of Jurassic beds interposed between the Trias ami Creta-
Further east and north, through Kansas and Nebraska, the Dakota
Cretaceous rests in places on Trias, at other- on Permian or Carboniferous
beds. The chalk beds, which in Texas correspond to the lime-tune- of the
Niobrara along the foot-hills of the mountains, have also been found in
eastern Kansas, and recently in Nebraska as I'm- west a- the L03rd meridian.

General Conch -The present distribution of Mesozoic Bediments in

\m JOUI I . V., I. WW III, 1880, !•. 1-".

; ii • • • for i-TT, p. jsu.

THE MESOZOIC GEOGRAPHY. 277

the interior region of our continent shows that there were two principal

meridional lines of depression in the earth's surface at that time, the one in
the region of the Great Plains to the east of the Rocky Mountain front and
the other to the east of the Wasatch uplift, each of which probably extended
north beyond the Canadian boundary. The western continent beyond the
Wasatch mountains had its greatest east and west extension between the
40th and 45th parallels of north latitude, the Mesozoic ocean extending
further westward both to the north and south of this continent and possibly
connecting beyond our boundaries with that on the Pacific slope. It is
probable, therefore, that in these middle latitudes the general level of the
country, as represented by its plains and valleys, was higher than in the
more northern and southern regions, the bottoms of the principal depressions
having a general slope northward and southward toward the present oceans.

The general elevation that accompanied the Jurassic movement therefore
raised the whole interior region above the ocean, while the dynamic move-
ments produced the effects already noticed within the Rocky Mountain
region, and also raised a barrier which kept out the waters of the southern
ocean, or Gulf of Mexico, from the eastern and partially, or possibly entirely,
from the western meridional depression.

During the elevation a fresh-water lake, whose extent is as yet imperfectly
defined, accumulated behind this barrier. It filled the valleys of the Rocky
Mountain region and extended north as far as the Black Hills. It must
have filled a portion at least of the Great Plains depression, but its western
shore-line is now buried beneath Cretaceous deposits and may never be accu-
rately defined. The extent of fresh-water Jurassic beds on the south and
west of the Rocky Mountain region will, however, probably be determined in
future examination of the region. At present it can only be said that fossils
apparently belonging to this horizon are said to have been found in north-
ern New Mexico by Newberry on the south, aud on the banks of the Green
river in Wyoming by Steward, of Powell's party, on the west.

During the gradual subsidence which followed this elevation the barrier
was being eroded, and an outlet may have been formed through which the
Jurassic lake was drained, so that no further deposition went on in its bed
until it was again invaded by the ocean ; though, as far as present evidence
goes, the subsidence was not sufficient to admit the wraters of the ocean
within the Rocky Mountain region until Dakota times. Marine water-,
however, must have entered the western depression from the north in Brit-
ish Columbia to admit the deposition of the Kootanie series of beds, and it
seems not improbable that marine Cretaceous beds below the Dakota may
yet be found in the western depression to the south, in the Plateau province.

That a certain amount of erosion of the fresh-water Jurassic beds after
the drainage of the lake may have taken place in the Rocky Mountain

278 3. F. EMMONS — OROGRAPHIC MOVEMENTS.

region seeraa probable from their apparent absence in certain sections and
from actual proof of local movement and erosion discovered by Mr. Kldridge
at Golden, Colorado ; but it cannot yet be said that there was a general dy-
namic movement preceding Dakota time corresponding to that which Mr.
Hill assumes to have affected the northern portion of Texas before the depo-
sition of the upper Cretaceous there.

The character of the sediments and of the contained organic remains of
the Dakota Cretaceous throughout the whole interior region, however, shows
that they were deposited in a slowly advancing ocean during a progressive
subsidence of the whole region. This subsidence continued to the middle
of the later Cretaceous time, and was followed by an equally gradual ele-
vation, which culminated in the shallow water conditions of Laramie time,
when the oceanic waters finally retreated from the interior region even more
slowly than they had advanced, never to penetrate it again.

The same general succession or cycle in the character of sediments depos-
ited during later Cretaceous time may be observed throughout the interior
region, though a variation is found in the thickness and in the prevalence
of coarser or liner materials of the series as a whole, according as they were
deposited near elevated land-masses and in narrow bays, or in broader seas
at a distance from any considerable land-masses. While the sedimentation
during this cycle was essentially conformable and undisturbed in character,
a lew unconformities by erosion have been observed, which indicate at least
local movements about the middle of the period whose extent will probably
be increased by future investigations. These are, an unconformity by ero-
sion at the close of the Niobrara Cretaceous observed by G. Eldridge* at
Golden, Colorado ; one noted by F. 15. Meekf at the same horizon on the
Missouri; and a third at Austin, Texas, described by K. T. HillJ.

The occurrence of lacustrine life in the Belly River ami Dunvegan beds
in Manitoba may likewise be found to be some way connected with these
movements.

Correlations. — On the Atlantic border there is direct evidence of an oro-
graphic movement which seems to cqrres] I pretty closely in geological

time with that jus! described. The Triassic series of the eastern slopes, which
include in places bed- that arc considered by some to be of Jurassic age. were

uplifted, folded, and extensively eroded before the deposition of the succeed-
ing Cretaceous beds. The earliesl of the latter -cries, the Potomac forma-
tion, is essentially a shore-line deposit, and though its age is uol fullyagreed
upon, some regarding it as late Jurassic and others as early Cretaceous, it
may probably be considered to be the stratigraphical equivalent of the beds
first deposited after the Jurassic movement in the Rocky Mountain region.

• Bull. Philosophical Boo. ••! Washlngl Vol \ i. [881 proi

+ f 3urv. of the Territories, Vol. IX : invertebrate Palaeontology. Washington, 1

XXXIII.
J Atncr. Jom Vol. XX X IV. I--T

CORRELATIVE MOVEMENTS TX THE SIERRAS. 279

On the Pacific border of the western or Nevada continent, both stratigraph-
ical and paheontological conditions are much less easily defined. Whitney
and King regarded the Jurassic beds of western Nevada, which apparently
overlie conformably the Star Peak or Alpine Trias, as of the same age as the
auriferous slates which are upturned against the western flanks of the Sierra
Nevada, and considered the uplift of the Sierra Nevada as post-Jurassic and
contemporaneous with that which folded the Nevada beds. As the Jurassic
fauna of the latter corresponds with that of the marine Jura of the interior
region, the movement would closely correspond with the Jurassic movement
we are now considering.

Later observations by Mr. G. F. Becker* and Dr. C. A. Whitef differ in
some respects from the conclusions drawn by Whitney and King. They
consider the auriferous slates (Mariposa beds) to be palreontologically distinct
from the Nevada Jurassic and to be more closely allied to the Knoxville
beds of the Shasta group. Dr. White is not fully decided as to their age,
but is inclined to place them in early Cretaceous (Neocomian) or late Jurassic.
The Chico-Tejon beds, which rest unconformably upon the Shasta group,
he considers as in part very latest Cretaceous (in this confirming Mr.
King's earlier view) and in part early Eocene. While Mr. Becker does not
commit himself definitely to a statement of the change in previous orographi-
cal views which this would involve, doubtless because he was on the eve of
obtaining further and more decisive data from his proposed detailed study of
the auriferous slates of California, he evidently foresees the necessity of some
such view as the following, if future investigation confirms the conclusions
then reached by Dr. White and himself. This is, that an uplift of the Sierra
Nevada region occurred at the close of the Nevada Jurassic which perma-
nently excluded the ocean from western Nevada and established the shore-
line of the Mariposa beds and their contemporaries west of the crest of the
Sierra Nevada, and that the movement which upturned these beds and pro-
duced the main uplift of the Sierra Nevada occurred in Cretaceous times
previous to the deposition of the Chico-Tejon series and hence may prove to
have been closely related to the great post- Laramie movement of the Rocky
Mountain region.

It is an interesting coincidence that in Europe, also, there occurred an
orographic movement in Jurassic time, in consequence of which, according
to the generalizations of Suess| and Neumayr,§the sea retreated entirely from
the middle regions of Europe, where toward the close of this period only
fresh-water sediments were deposited, and not until Cretaceous time did ma-
rine forms again appear.

*Bull. No. 19 U. S. Geol. Survey, Washington, 1885.
t Bull. No. 15 U. S. Geol. Survey, Washington, 1885.
X Antlitz der Erde. II Bd., Wien, 1888, p. 350.
I Erdgeschichte. II Bd., Leipzig, 1887, p. 387.

XXXVII— Bull. Geol. Soc. Am., Vol. 1, 1889.

The Post-Cretaceous Movement.

The post-Cretaceous movement, as has been almost universally recognized,
was that which produced the main plication and faulting and played the
most important part in determining the present orographic features of the
Rocky Mountain region. But, as it is evidenl that these features had been
in a great extent already outlined in the movements that went before, it is
also more than probable that the post-Cretaceous folds and faults have been
further emphasized along the principal lines of disturbance in the less violent
movements that have affected the region since, even into very recent times.
It is therefore manifestly impossible to determine with absolute accuracy how-
much of the present displacement of Cretaceous beds in folds and faults was
produced in the first post-Cretaceous movement and how much in those that
have supervened in Tertiary and Recent times. That during this movement
the tangential thrust or force of compression was very intense is proved by
the fact that in very disturbed regions the upper beds of a series, upturned
against the flanks of an ancient island, often stand at steeper angle than the
lower beds of the same series, producing thus something similar to the fan
structure observed in the Swiss Alps.

The character of the sediments deposited during the periods immediately
preceding this movement, which show gradually shallowing waters during
the Fox Hills period, culminating during the Laramie in an entire change
of its fauna through brackish-water into fresh-water forms, indicates a
gradual elevation of the land until barriers similar to and perhaps more or
less corresponding with those formed during the Jurassic movement cut off
the whole interior region from the ocean. It might naturally be expected
that during such elevation the shore-lines of succeeding stages would recede
somewhat, and such Dr. White : slates to have probably been the case with
the eastern shore-line of the Cretaceous ocean in the < rreal Plains depression,
which, he considers, alter reaching its greatest extension during the Niobrara
was carried westward during late Cretaceous times. In the Rocky Mount-
ain region, where erosion and denudation have naturally been greater than
in the plain regions, it is more difficult to determine the original extent of
the beds last deposited previous to the orographic movement, since these
were necessarily the lirsl to suffer abrasion and denudation, which would
have carried their outcrops further hack from the original Bhore-line of the
continental islands than those of the Bubjacent beds. Still, some idea of the
probable extent of the Laramie deposits can be formed by considering to

what extent they -till occupy the great valley depressions formerly covered

by the < Iretaceous -■ as, since there denudation would have been less uniform

and thorough than on the mountain Blopes and ridges.

* Hayden'a Eleventh Repot I (for 1877), p.
(280)

FOSSILS OF THE MIDDLE PARK BEDS. 281

Laramie Land. — At the present time, within the mountain area roughly
defined by the east flanks of the Colorado range on the east, by the Laramie
plains, the Park range, White river plateau, and Elk and San Juan mountains
on the west, and by the southern flanks of the San Juan and Sangre de Cristo
ranges on the south, no beds of the Laramie or coal-bearing formation
proper are known with certainty to exist, except in the South park. The
beds which form the dividing ridge between the North and Middle parks,
and which were colored on the Hayden maps by Marvine as of Laramie age,
were so determined solely on the evidence of fossil plants, in spite of their
unconformity with Cretaceous rocks below and their want of lithological cor-
respondence with the Laramie beds developed elsewhere in Colorado. In
North park Mr. Marvine discovered, in beds which he referred also to the
Laramie group, though without expressing any opinion as to their strati-
graphical equivalence with the Middle park beds, a few molluscs, of which
Dr. White, after an examination of all the evidence both in field and office,
says : " Of themselves they are not sufficient to determine the age of the strata
containing them or their equivalency or otherwise with those of the Laramie
group."* A recent examination of these Middle park beds made under my
direction by one of my assistants has satisfied me that they were deposited
after the post-Cretaceous movement, and that if Laramie beds proper were
ever deposited in the Middle park they have since been removed by erosion.
As in the adjoining South park Laramie beds still remain under very similar
physical conditions, there seems to be some reason for assuming that the
Laramie shore-line did not reach as far south in the Middle and North park
depression as did that of the earlier Cretaceous seas in which case the bay in
which the South park Laramie was deposited must have had its connection
with the open sea by way of Canon City.

In Huerfano park, which forms the southern end of the Wet Mountain
valley depression, Laramie beds still underlie unconformably the Eocene
Tertiary deposits which Mr. R. C. Hills has recently discovered there, but
it is not probable that they ever extended much further north in this depres-
sion than the present divide.

No Cretaceous deposits whatever have been found in the depression of the
San Luis valley, and if this depression, as I assume on confessedly rather
indefinite grounds, was formed, like the valley of the upper Arkansas,
by post-Cretaceous displacements and recent erosion, the Cretaceous seas
did not cover it at all, except possibly the extreme southwestern border now
buried beneath recent eruptive rocks.

On the western edge of the mountains, on the other hand, the great area
of the Uncompahgre plateau and the valleys of the Gunnison and lower
Grand river, from which the upper Cretaceous beds are now almost entirely

* Op. cit, p. 203.

282 S: 1'. EMMONS — OROGRAPHIC MOVEMENTS.

absent, was probably to a great extent covered by the Laramie deposits,
which may also have covered a great part of the present area of the 101k
mountains and of the White river plateau.

< >n this method of reasoning, therefore, it would appear that already in
Laramie time the ocean waters had in great measure receded from the in-
terior portion of the Rocky Mountain region which they had occupied in the
earlier part of the Cretaceous period, hut that this recession was accompanied
by do dynamic movements. These movements were initiated only after the
coal-bearing Laramie beds had been deposited, and whatever sediments were
formed in the region after these movements were laid down in lacustrine
watei s.

1 1 Ue qf il<< Movement. — I have spoken of this movement as post-( Iretaceous,
although, as occurring at the last stage of that series, it might more strictly
hr .idled post-Laramie. Twenty years ago the former term might have been
objected to as fixing too early a date for the movement ; to-day there seem-
to he some danger of a similar objection heing made to it on the ground
that it implies too late a date. All geologists are more or less Familiar
with the controversy which existed so long as to the age of this important
formation, which carries almost all the economically valuable coal deposits
of the Rocky Mountain region. It arose mainly from the fact that in the
earlier explorations fossils were brought in from widely separated districts
whose stratigraphy under the circumstances could not he exhaustively Btudied ;
hence correlations had necessarily to be made on palaeontologies.] evidence
without that accurate knowledge of the stratigraphical succession and struct-
ural nlatioii- of the beds in question which is an indispensable basis for the
correct determination of horizons in a new geological field. The determi-
nations made by various classes of specialists under these conditions presented
a wide range for the same series of beds. By the vertebrate palaeontologists
the Laramie was considered without doubt of Cretaceous age. From a
study of its mollu8Can remain.- opinion.- varied between Cretaceous and
Tertiary, with a decided leaning toward the latter; while the palseobotanists
assigned some of its beds to the Miocene and others to the upper Eocene,
the former heing in actual stratigraphical position nearesl the base of the
-■■i ii

The geologists of the Fortieth Parallel, who first introduced in the western
mountain region systematic examinations of continuous areas based on topo-
graphic maps of these area.-, after following Laramie outcrops in a belt one
hundred miles wide across eight degrei - of longitude, found that Btatigraph-

ically and structurally il belongs to the Cretact s, forming the closing

phase of a continuous sedimentation through thai period, and being followed
by the mosl marked physical break .-inc.- that at the close of the Archaean.

THE STRATIGRAPHICAL POSITION OF THE LARAMIE. 283

Professor L. F. Ward*, in his historical review of the opinions held iu re-
gard to the Laramie group, seems to regard the point of view assumed by
Mr. King in summarizing the evidence on this subject as puerile ; neverthe-
less I am convinced that much of the confusion that has obtained in the
minds of palaeontologists in regard to the proper position of these beds in the
geological column would have been avoided had they possessed an accurate
knowledge of the stratigraphical relations of the beds of each locality from
which their fossil evidence was obtained.

No one has done more to reconcile the opposing views and clear up this
confusion than Dr. C. A. White, who has combined in his work the qualities
of the structural geologist with those of the palaeontologist. In his recent
review of the North American Mesozoic f he says :

" The formations which overlie the Laramie were, by common consent, long ago re-
garded as of Tertiary age; but concerning the age of some of them, differences of
opinion have since arisen. Between the Laramie and any overlying formation there
is often, but not always, unconformity. In Utah, and apparently in the valley of the
Yellowstone also, I have found the Laramie passing gradually up into purely fresh-
water deposits without any stratigraphical break. In the former case I am sure, and
in the latter case I believe with Professor Newberry, that the upper strata represent
the lower part of the Wasatch group."

Without knowing more about the locality referred to than is here ex-
pressed, I should not consider, from a stratigraphical standpoint, that this
disproved in any degree the unconformity, and the orographic movement
which that implies, between the Laramie and the Wasatch ; since in the
broader depressions away from the immediate vicinity of a line of disturb-
ance the succeeding beds, even after a physical break, may be expected to
be found quite conformable with those below them. As regards continuance
or non-continuance of certain forms of life across such a break, I do not
wish to invade the province of the biologist in offering an opinion, but
would merely suggest that the probable persistence of land areas of some
kind throughout the various orographic changes that have occurred in this
region, which I have here insisted on, would seem to be of some importance
in explaining survivals here wdiich are unusual in other regions.

As regards the coal-bearing Laramie in the Rocky Mountain region, which
I have hitherto spoken of as the Laramie proper, it has now been examined
more thoroughly than any other formation on account of its economic im-
portance, and those who have carefully studied it in one locality find no
difficulty in recognizing it in others, in spite of local variations in character
of sediment and thickness of beds. Its exact relation to the beds which
have been deposited upon it since the movement in question are, however,

* Synopsis of the Laramip Flora: Sixth Ann. Rep. Director U. S. Geol. Survey, Washington, I881
t Proc. A. A. A. S., Vol. XXXVIII, Aug.. 1S89.

284 -. P.. EMMONS — OROGRAPHIC MOVEMENTS.

often obscure in a given section, and can only be accurately determined by
a careful stratigraphical study of a considerable area. This is well illus-
trated in the case of the Denver region, of which a tnosl exact and detailed
survey has been made recently under my supervision by Messrs. Cross and

Eldridge. They have shown that, since the movement at the close of the
Laramie proper, there have been deposited upon its eroded surface two
succeeding series of beds, of a thickness of 800 ami 1,400 feet respectively,
called the Arapahoe and Denver formations, the former of which was up-
lifted and eroded before the deposition of the latter. The greal Lengtb of
time that must have elapsed subsequent to the post-Cretaceous movement is
proved by the fact that the Arapahoe formation is made up of material
recognizable as derived from different horizons of the 14, oho odd feet of
Mesozoic beds upturned by it. including the Laramie. It is further empha-
sized by the composition of the beds of the Denver formation, which are
largely, and in their lower portion almost exclusively, made up of debris
of a very great variety of andesitic rocks, none of which could be found in
the lower beds and the source of which has not yet been discovered in the
adjoining regions, showing that the interval must have been of sufficient
length to admit of the outpouring of a great variety of andesitic rocks and of
their almost complete denudation before the close of the Denver period.

in earlier examinations of the region, on account of the peculiarly com-
plicated structural conditions, all these beds had been assumed to belong to
one conformable series, and the plants collected from the Laramie beds and
from the Denver beds above are indiscriminately designated by Pro-

- ir Ward, in his Synopsis, as '-from the Laramie at Golden," although
I had previously called his attention to our discovery of the unconformity
and pointed out the differences in the matrices of the respective specimens in
his collections.

With regard to the age which would properly be assigned to these
I ater beds from a palseontological point of view — thai is, as determined by the

general laws of BUCCession of animal and plant life, which the pit-sent
knowledge of the development of life in Mesozoic ami Tertiary times in
other part- of the world have led biologists to make, —there exists considera-
ble uncertainty. Of the organic remains thus far discovered neither plants

nor invertebrates can be considered of sufficient tax >mic value to afford

decisive evidence as to their Cretaceous or Tertiary age. The vertebrate
remain-. on the other hand, present the m aresl analog; to a recently described
vertebrate fauna, assigned by its discoverer to the Laramie Cretaceous. No
published evidence exists of the stratigraphical or structural relation- of the
bed- in which these occur; only the hare statement of the author that they
belong to the Laramie. Furthermore, il is known that some of the beds,
who-e fauna i- -aid by palaeontologists to have a Laramie facies, are dis-

PAL.EOXTOLOGH'AL AND STRATIGRAPHICAL METHODS CONTRASTED. 280

tinctly fresh-water and separated from the Laramie proper, or, as they desig-
nate it, "the lower Laramie," by a physical break; and this I have reason
to believe is the case in at least one locality where the vertebrate fauna,
which that of the Denver beds most resembles, has beenfouud.

Conclusions — In no region can the palaeontologist afford to neglect the
evidence of stratigraphy and geological structure, and this is especially true
in a new and extremely complicated region like the Rocky Mountains, where
already the succession of life has been found in certain horizons to vary
quite markedly from the laws previously established by studies in Europe
and the east. The stratigrapher, on the other hand, must necessarily depend
on the palaeontologist for such determinations of the relative age of his
horizons as will enable him to establish correlations betweeu different series
of beds between which there may exist stratigraphical or geographical gaps
or hiatuses.

For the accumulation of material essential for true and complete geologi-
cal history of a given region it is therefore necessary, not only that each
should freely furnish the other with all the facts he has determined from his
particular standpoint, but also that he should draw his conclusions, not from
that standpoint alone, but give due weight as well to the evidence afforded
from the standpoint of his collaborator.

It is in pursuance of this idea that I have laid stress upon the importance
of the movement at the close of the coal-bearing Laramie in the Rocky
Mountain region ; and I desire to protest against what seems to be a tendency
among those who are studying the pakeontology of the region to give little
weight to it, or even to neglect it altogether in their determination of hori-
zons. It is unquestionably one of the most important events in the orograph-
ical history of the entire Cordilleran system. With the exception of the
great unconformity between the Archrean and all overlying sediments,
which is a phenomenon sui generis and altogether exceptional, no movement
has left such definite evidence as that which followed the deposition of the
coal-bearing rocks, to which the name Laramie has by universal consent
been applied. Against the positive testimony of nearly horizontal beds of
Eocene or later age actually overlapping the edges of more or less steeply
upturned Laramie beds, found iu so many and in so widely separated por-
tions of the region, the negative evidence of conformity of angle between
these beds in other localities has absolutely no weight at all.

It is further a fact universally admitted that while the beds deposited pre-
vious to the Laramie were marine, all deposited since that period were essen-
tially fresh-water sediments. Now, it is kuown that land and fresh-water
molluscs are of little value as indices of the passage of geological time. Tt
seems reasonable, moreover, to assume that, iu a region where land surfaces
have existed throughout the orographic movements, fewer extinctions or

286 >. p. EMMONS — OROGRAPHIC MOVEMENTS.

changes in plant life would be produced in t lie progress of geological time
than where such movements produced an entire submergence of adjoining
land areas. Hence it is to the successive changes in vertebrate life that we
must look for the most definite palaeontologies! evidence of the lapse of geo-
logical time.

Palaeontologists tell us that, between the vertebrate fauna of the lowest
Eocene beds yel studied in this region and that of the Laramie, there is an
important gap in the normal succession of life that remains to be filled. It is
now over fifteen years since Mr. King stated from the evidence then available
that no Eocene beds' existed on the eastern flanks of the Rocky Mountains,
and this statement has held good until within the last year, when an exten-
sive series of beds, over 7,000 feet thick, discovered by Mr. R. C. Hills at
Huerfano park, on the eastern flanks of the range, have been determined to
be in part of Eocene age, though they have not yet been sufficiently studied
to determine their entire vertical range in the geological column. These
beds overlap the upturned edge of the Laramie beds, as do, or did before
removal by erosion, the Arapahoe and Denver beds already alluded to. It
is probable that, as special investigations to this end are made, other scries
of beds, occupying an intermediate position between the lowest Eocene now
known in the region and the coabbearing Laramie, will be discovered;
and it may be hoped that in time the gaps in the succession of life may
be filled. From the nature of things it will probably be a long time 'ere
Buch a complete knowledge of the succession of fauna can be obtained.
These later beds were of limited and local extent, they have Kern hut im-
perfectly consolidated since their deposition, and, being the first to be affected
by Tertiary erosion, they exist now only in fragmentary patches; hence it
requires such minute and detailed study to determine their true Btratigraph-
ical relations as in the present stage of geological investigation in this coun-
try can seldom lie accorded to them. Hence all determination.- of BUCCes-
Bion of life based on pahuontologieal evidence alone, must for a long time be
provisory. It would seem, therefore, to be illogical, when there is an appar-
ent conflict between the definitely determined physical evidence of an oro-
graphic movement and that afforded by analogy with the laws of succession
established in other parts of the world, to allow the former to he neglected
or even to be outweighed in making such provisory determinations.

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA

Vol. 1, pp. 2$7-3io

ON GLACIAL PHENOMENA IN CANADA

ROBERT BELL, B. A. So., M. D., L.L. D.,

ASSISTANT DIRECTOR OF THE GEOLOGICAL SOCIETY OP CANADA.

WASHINGTON

PUBLISHED BY THE SOCIETY

April, 1890

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA

Vol. 1, pp. 287-310 April 5, 1890

ON GLACIAL PHENOMENA IN CANADA.

BY ROBERT BELL, B. A. SC, M. D., LL. D., ASSISTANT DIRECTOR OF THE

GEOLOGICAL SURVEY OF CANADA.

{Read by title before the Society December 26, 1889.)

CONTENTS.

Pago.

Introductory Note 287

The Evidence concerning Kepetition of Cold Epochs 288

Geographic Changes of the Pleistocene 288

The Ante-Pleistocene Surface 289

The Evidence of Glacial Action 291

The Direction of Glacial Flow 294

The Formation of Lake Basins 297

Keiiction of Rock Structure on Glacial Erosion 299

Lakes of Double Outlet 301

Discordant Strife 301

Lake Agassiz 302

Upward Movement of Bowlders 304

The Period of Glaciation 306

The Cause of Glaciation 309

The Causes of Changes in Level 309

Introductory Note. — In the following paper, Canada means more than the
narrow strip along the eastern part of the northern border of the United
States, with which the name was once familiarly associated in the minds of
the citizens of the latter country. Leaving out Alaska, Canada now means
the northern half of this continent.

The extent of the area in the northern hemisphere which has undergone
glaciation during the drift period has now been pretty well ascertained, and
the greater part of it proves to lie within the Dominion of Canada. Con-
sidering this fact and also the diversity in topography and climate presented
by a country which stretches from the temperate zone to the north pole, it
must be admitted that we Canadiaus have a splendid field for the study of
the ancient glacial phenomena.

In 1863 the writer prepared the chapter on surface geology in the
" Geology of Canada ; " and ever since that time he has paid particular
attention to this subject. His opportunities for persoual observation in all

XXXVTII— Bull. Geol. Soc. Am., Vol. 1, 1889. (287)

I:. BELL — GLACIAL PHENOMENA [N CANADA.

tions of the country east of the Rocky Mountains have been unequalled
by any other single traveller, and it is therefore hoped thai some points of
interest will be brought out in the following paper.

The Evidence concerning Repetition of Gold Epochs. — Have we had in
North America two or more distinct glacial periods, separated from one
another by long interval.-, of time? Thie is one of the Grst questions which
arise when we begin to classify our facts and describe the observed phe-
nomena. Limited deposits of lignite occur between layers of till, especially
in the more southern ami western parts of the drift region, where the ice-
Bheel was liable to advance and retreat according as the conditions were
more or less favorable for the accumulation of ice during cycles of years. I
have found similar deposits as far north as the southern part of Hudson'.- Bay.
liut these facts seem merely to indicate temporary and local interruptions of
the glacial condition, and do not afford proof of an interglacial period ex-
tending throughout North America and lasting long enough to require us to
consider thai there were two or more glacial periods wholly separated from
one another. On the contrary, it appears as if all the phenomena might be
referred to one general glacial period, which was long continued and con
quently accompanied by varying conditions of temperature, regional oscilla-
tions of the surface, and changes in the distribution of sea and land and in
the currents in the ocean. These changes would necessarily give rise to
local variations in the climate, and might permit of vegetation for a time in
regions which need nol have been far removed from extensive glaciers.

Geographic Changes of the 1'1'iMocene. — Geological explorations have now
been made in all parts of the Dominion sufficient to show that the glaciation
of the surface east of the Rocky .Mountains has been universal, except in the
northern part of the eastern Labrador range and perhaps in some of the
higher parts of Baffinland. It is doubtful also if the Gaspe* peninsula has
been glaciated, excepl locally. What was the condition of the now glaciated
ana before the commencement of the drift period?

The relative contours of adjacent districts were probably something like
what they are to-day, but regional elevation and depression have made greal
differences in the distribution of land and water on a grand scale. Th<
changes of level, going on during the progress of the ice a'_re. made great
alteration.-- in the distribution of the ice-sheets ami in the movements of th<
wide-spread glaciers themselves, a- proved by the various courses of the ice-
grooves and the different directions in which the drift materials have been

transported. The latter, alter having been moved in one direction, have in

some cases been partly carried off in another, owing to a change in the
com-.' of tin- ice movement. These changes of movement may have been
brOUghl about by an increase or diminution in the Blope of the land or the

relative elevations of different districts, but probably also largely on account

MARINE SHELLS AND DEPOSITS FAR INLAND. 289

of altered conditions affecting the influence of the sea in one direction or
another. For example, a comparatively small depression might establish a
wide channel connecting two oceans. Such a thiug might be conceived as
taking place between Avaters covering the valley of the Mississippi and
Mackenzie rivers. This would at once have an immense effect on the
glaciers, which we may suppose to have existed on both the Laurentian and
the Rocky Mountain sides of such a great strait.

Changes in the proximity of the open sea in the valley of the St. Lawrence
and elsewhere may help us to account for the different directions followed
by the ice-grooves and by the drift materials in these regions, as well as the
changes in the elevations or slope of the land, which such alterations in the
distribution of land and water would imply. That such changes have taken
place appears to be pretty well established. Among other proofs of this is
the fact that marine shells are found in the Pleistocene deposits along the
St. Lawrence only as far west as Brockville, about 200 feet above the sea,
where they have assumed the brackish water forms ; whereas on Montreal
mountain they occur up to an elevation of 500 feet, which is sufficient to
have carried the sea all over the basin of Lake Ontario had the relative
levels of the land remained the same as at the present time.

The Ante-Pleistocene Surface. — What was the condition of the surface of
the northern part of the continent just before the commencement of the
glacial period? There is every reason to believe that the Archean rocks,
which occupy so large a portion of the glaciated area, had become deeply
decayed and softened like those of the southern States, Brazil and Ecuador,
at the present day. This softened crust would be easily ground up and
swept away by the ice-sheet to form the deep and extensive layers of till
which cover such large tracts in the more southern regions of Canada and
extend into the United States. These layers have an average depth of perhaps
100 feet all over the extensive Paleozoic districts west and south of Hudson's
and James's bays and in those of the province of Ontario, and the average
depth may amount to 200 feet in Manitoba and a great part of the Northwest
Territories. This till is largely mixed with the debris of the local Paleozoic
or Mesozoic rocks, but so vast an amount of loose material could not have
been produced by the glaciers working on a surface originally as hard and
bare as that of the Archean rocks at the present time.

The rounded bowlders are probably to a great extent the remains of the
hard nuclei or kernels, which, for some reason, in the case of crystalline rocks,
remain unaffected in the decay of the surrounding mass, although a certain
proportion of them, as well as nearly all the angular and sub-angular bowl-
ders and the pebbles, have resulted from the breaking and shattering of
the rocks along cliffs or about peaks and from the peeling up of beds beneath
the glaciers.

290 l;. BELL — GLACIAL PHENOMENA EN CANADA.

The general outline of the gnat Archean area of the northeastern part of
the continent and Greenland approaches an elliptical form, but its superficial
continuity is broken in place- by shallow water or thin basins of Paleozoic
ks. 'The whole area (excluding Greenland) has only a moderate eleva-
tion above the sea: and, on the Large scale, it may be considered as nearly
level, being interrupted only in a few parte by heights which can be called
mountains. Yet every part of it which is not buried under the drift is broken
up into isolated rounded hummocks, a condition which is best described as
mammillated. The whole vast country has been planed down bo thoroughly
and deeply that few traces of the preglacial surface remain. The northern
part of the coast range of eastern Labrador, probably the highest ridge in
Canada east oi the Rocky Mountains, has not Keen glaciated except locally
in the valleys. It consists of Laurentian gneiss, like the rest of Labrador,
but without a close examination one would not recognize in the peaks, ser-
rated ridges, and earthy looking slopes of these mountains the same rock-
that constitute the bar,e, hard, flattened domes of the Laurentides elsewhere.
This range was probably much more elevated during the ice age and formed
the Btarting point of the glaciers, which flowed northward into CJngava bay
and westward into Hudson's hay. From the latter their course was still
westward and Bouthwestward to the western holder of the Archean region
and far beyond it in the Saskatchewan and .Mackenzie river basins.

In the Gaspe* peninsula, too, there appears to be an absence of travelled
bowlders, if not of general glaciation, as was pointed out by the writer in

L859. In most parts of the region affected by the drift tin ly fragments

of the preglacial Burface bo far discovered consist of limited beds of liguile
and trace- of the channels of rivers cut in the solid rocks, which are usually
buried beneath the till.

In the valley of the Athabasca river towards the periphery of the
glaciated region, where the ice-sheet was probably much thinner than over

the Laurentian area to the east of it. the valley- hear evidence of preglacial

origin. Some facts in this connection are given in the Geological Survey

report by the writer for 1882. The depth and grandeur of the valley of the

little Clearwater river have been remarked by all travellers in these parts.
Thi- Btream flows westward and joins the Athabasca aboul 150 miles Bouth
of Athabasca lake. Above the junction the bed and valley of the main
river are only large enough to accommodate the present stream, bul below it

the valley immediately Income- ahoiit a mile wide, with a level, w led in-
tervale Ltwe. n the hank-, while the present river has a width of only one

or two hundred yards. The Clearwater has steep hanks from 500 to 600
feel high, with a width of about a mile between theirkbrinks. In my report
for l>,v'_'. I stated that "the valleys of both the Athabasca and Clearwater,
ae far a- thej are excavated in the Cretaceous and Devonian strata, may be

EVIDENCE OF PREGLACIAL EROSION. 29]

of preglacial origin. There appears to be. no evidence that these rivers
themselves removed so large an amount of rock ; and drift materials, similar
to those of the higher levels, are deposited equally below the more ancient
walls." * The channels of the Clearwater and of the lower part of the Atha-
basca evidently form a continuous valley of large size, through which a
greater river flowed for ages before the glacial period. The direction of the
current of this stream would depend upon the slope of the country at the
time. There is said to be a continuous water-course between the head of
Clearwater river and Clearwater lake, connecting again with Isle ;i la Crosse
lake, out of which the Churchill river flows. A slight elevation to tin- cast-
ward would send the waters of the upper Churchill and all the drainage of
the Isle a la Crosse basin down the Clearwater river, while on the other
hand a greater elevation to the westward would turn the waters of Lake
Athabasca and Peace river into the Churchill.

In the lower part of the Churchill river I found, in 187!), ancient gravel-
filled valleys, excavated in solid limestone, and all covered over with bowlder-
clay. Similar evidence of preglacial erosion was noticed in limestone in
the lower part of Nelson river. On the Missinaibi river (southwest of
James's Bay) I discovered several beds of lignite with till both above and
below them. Another bed of lignite, three feet thick, which I have de-
scribed on Coal brook, a channel of this river, rests upon blue and light
colored clays and is overlain by about seventy feet of till. Traces of lignite,
of the age of the drift, were also met with on Albany and Abittibi rivers.
In one place the Kenogami river, which discharges Long lake into the
Albany, cuts across an ancieut valley, excavated in Silurian strata with a
bed of lignite in the bottom and filled with drift materials, which also over-
spread the surface of the older rocks on either side of the preglacial chan-
nel. Lignite occurs beneath the drift on Rainy river and on the western
side of the main body of Lake of the Woods. The lignite, or buried peat,
of the south shore of Lake Superior and that of theGoulais river, on itseasf
side, are overlain by modified sand and clay of more recent date than the
till. But evidence of this kind is comparatively rare. It is seldom that
anything is found between the till and the glaciated surface of the funda-
mental rocks.

The Evidence of Glacial Action. — With the exceptions already noted, the
whole surface of the Dominion from the boundary of the United States
northward to Baffiuland has been thoroughly ice-swept. In spite oft lie
mammillated aspect of the vast Archean region, the evidence of this greal
planing and denuding force is everywhere manifest. Its appearance on the
grand scale may be compared to that of a hummocky surface of plastic clay
which had been stroked by the han 1. The valleys and the sides and tops

*Geol. Survey Report for 1882, page 30cc.

292 R. BELL — GLACIAL PHENOMENA IN CANADA.

of the hills have been alike rounded and smoothed — no place seems to have
iped. The proofs are innumerable thai the denuding agency could have

bee thing bul land ice acting as a semi-fluid. There is no evidence that

ice-bergs or other forms of floating ice had anything to do with the erosion.
The general contours of the surface slope in various directions and the
differences in level are very considerable, so that if this had once been the
bottom of the sea there would be corresponding differences in depth.

h should be remembered by those whose imagination pictures ice-bergs
performing the work of glaciers that, as a matter of fact, when a berg takes
the bottom it Btop'fi i atirely and often remains for years stranded at the same
spot. The ice-grooves and furrows on the surface of the rocks constantly
show that the yielding force, while producing them, must have been slowly
forced round projecting knobs, through crooked channels of varying width,
up hill and down dale, the upward slope being often very steep indeed ; that
perpendicular walls and even the under sides of overhanging rocks are
frequently grooved horizontally; and, altogether, that this force must have
acted in a manner quite impossible for ice-bergs. To those who have seem
much of the glacial phenomena in Canada, it seems incomprehensible that
any man calling himself a geologist could believe these phenomena to have
been produced by ice-bergs, provided he had had opportunities of observing
at all. Such totally unsupported views could only be held on the'' authority "
of some of the older geologists who paid more attention to theory than
observation, and who happened to jump to the conclusion that the ice-
gTOOVes and furrows had been produced by the rubbing of bergs on the
bottom of the ocean, and that the transported bowlders had been dropped
from such bergs a- they passed along. This latter notion may be equally
fallacious with the first, for the ice-bergs of modern time-, at any rate, trans-
port very lilt le earthy or rocky material. Field or floe ice is a more im-
portanl transporting agent, but it is the finer materials, such as mud, sand,
and gravel, which are carried by this means.

It i- probable that nol only were vast quantities of loose material;-, derived
from the decayed Burface, pushed forward under and in front of the ice-sheete
of the drift period, but that a large amount of similar d€bris was incorporated
in the substance of the ice itself. The latter would have a much more
powerful effect in abrading the rocky surface than materials which were \'v>'<-
to move and seek shelter wherever the pressure was least. Two points which
have sometimes been overlooked require consideration in this connection :
First, i he eif, ci of the i em perat u re of the ice itself, because, of course, ice is
capable of any temperature from that of the melting point down to the lowest
possible di ond, the hydrostatic pressure of the great superin-

curnbenl mass upon the lower layer-, for ice on the lame scale would obey
the same laws as a fluid. Those who have noticed the slight effect of modern

THE GRINDING ACTION OF GLACIERS. 293

glaciers in forcing along bowlders or in producing striation of the underly-
ing rock-surface should remember that their observations were confined to
the melting extremities of glaciers when the temperature of the ice was at
its highest possible point and when the hydrostatic pressure had almost
vanished. The latter circumstance enables the ice to gradually rise and ride
over the till, while the softened and comparatively warm ice, on the point
of melting, would offer the least resistance to bowlders or any other solid
objects. It should be further remembered that when these objects have
become exposed so as to be visible to the eye they must constantly absorb
heat from the air in summer and thus, as it were, thaw their way into the
glacier as fast as it advances towards them, producing grooves in its sub-
stance just as a stone will sink into ice by gravitation. If, on the contrary,
bowlders and finer debris be incorporated in very cold and hard ice thou-
sands of feet beneath its surface and firmly held in their places by the enor-
mous pressure from all sides, there can be no doubt of their acting as most
powerful abrading agents. In places wrhere the ice- sheet was from one to
two miles in thickness, as some geologists reasonably enough believe it to have
been, its weight would exercise not only an abrading but a tremendous
crushing and bruising effect on the surface of the rock beneath. At times
this would slightly displace great sections of rock exposed to its force and
gradually break them up and wear them into bowlders, some of which might
still remain of large size at the close of the drift period ; or if the whole,
mass should happen to settle into a protected situation, or if the ice should
disappear before breaking it up, the greater part of the mass might remain
till the present day. The crevices or spaces between the rock in situ and
the displaced mass would become packed with drift material, and the fact
that the displacement had occurred at all could only be discovered in the
side of a cliff, or by landslides or artificial cuttings.

A case of this kiud appears to have occurred at Wine harbor, Nova
Scotia, where a part of the area mined for gold seems to have been slightly
displaced en bloc, as a layer of hard gravel and mud was found separating
the upper hundred feet or so of rock from that below. In the cuttings
along the Canadian Pacific railway, north of lakes Huron and Superior,
seams or crevices filled with till are occasionally seen in the apparently
solid crystalline rocks. When building the line at Rossport, on Lake
Superior, a part of the mountain side including many thousands of cubic
yards, slid bodily into the lake in consequence of one of these openings.
It is probable that these crevices often act as reservoirs of water which
feed the springs among the Archean rocks.

When we think of the enormous weight of the ice-sheet with its abrading
materials beneath it, the only wonder appears to be that the evidence of its
crushing and gouging effects is not greater than we see. These forces are

294 R. BELL — GLACIAL PHENOMENA IN CANADA.

mosl conspicuously manifested where the more even course of the glacier has
been interrupted by a riseorturn, or by sonic hard knob of rock in its bed.
The immense pressure and the friction of the rocky debris would generate a
certain amount of beat, and the i<v, where very thick and mingled with
earthy matter, would tend to retard the radiation of heat from Mother
Earth ; for, notwithstanding the fact that transparent ice is a conductor of
heat, a mixture of ice and drift material a mile or two in thickness would
retain terrestrial heat, although in a less degree than an equal depth of
ordinary rock. The water thus produced would often be temporarily im-
prisoned and in the course of the movements of the ice would become sub-
jected to greal hydrostatic pressure, causing it to force passages for itself
among the debris. This might account for some of the singular forms as-
sumed by the drift materials.

The Direction of Glacial Flow. — The courses of the glacial stria' having
been noted in all parts of the northern States and the southern parts of
Canada before we knew much about them in the more northern region, it
was assumed that the general direction was everywhere southward, with
local variation- to the east and west of south. This circumstance, along with
the stupendous force which it was obvious must have produced the phenom-
ena of continental glaciation, gave rise to the theory of a universal ice-
sheet covering the northern regions of this hemisphere duriiig the drift
period. Our observations throughout "the great north land" have, how-
ever, modified this view, and it now appears as if Bomething less would
account for the wonderful facts of the great ice age in North America, as
well as in the Old World.

The dispersion of the ice doe- not appear to have been from a Bingle district
iii northern Canada, as supposed by some, but from several. One of tb<
as already stated, was in eastern Labrador; another lay between Hudson's
bay and the Mackenzie river; while the wide, shallow basin of Hudson's
bay itself formed the grandest neVe" and collecting ground of all. Besides

the ice which formed directly from the copious snows falling on this vast ex-

panse itself, continuous contributions were received from the Labrador penin-
sula to the easl and the great region to the northwest, and the mass discharged

itseli northward into the deep ami wide valley of Hudson's -trait ami south-
ward and Bouthwestward over the Paleozoic and Laurentian plateau. The
ice-sheet appear- to have flowed outward everywhere from the eastern,
southern, and western margins of the greal Laurentian plateau— that i- to
Bay, it- general course was eastward on the coast of the North Atlantic,
ithward from the Strait of Belle Isle along the St. Lawrence and the
Greal Lake- t., the Winnipeg basin, and Bouthwestward ami westward fr

thence ],, the Mackenzie river. A faint indication that the regions ea-t and
Wesl of Hudson's hay, above referred to, were firmer centres of glacial

POWERFUL AND PERSISTENT GLACIAL EROSION. 295

dispersion remains to the present day in the fact that the general isothermal
lines appear to circle round them as the areas of greatest cold. As the ice-
sheet increased or diminished there would, no doubt, be great local variations,
and immediately to the south of the general Laurentian outline there was
at one period a strong movement to the southwest up the St. Lawrence, from
near Montreal, through the basins of Lakes Erie and Ontario aud over the
peninsula between the latter and Lake Huron. A similar movement took
place from Lake Superior westward, carrying the debris of the red rocks of
the Nipigon formation up over the Laurentian plateau towards the valley of
Red river, as pointed out by the writer many years ago.

I do not like to offer any explanation of the above general facts ; but it would
appear that they indicate a greater elevation of the land than at present
exists in the north and east. In addition to the aid afforded by gravitation,
the movement of the ice was probably largely due to its continual accumu-
lation in certain regions and its constant thaw in others, the latter being
due not only to the heat of the sun but also to the influence of the warm
water of the ocean in the direction towards which the ice traveled. A fur-
ther cause of the southward tendency of the ice, which I have not seen
referred to by other writers, would be the tangential component of the
centrifugal force due to the rotation of the earth on its axis.

The Archean country is thoroughly denuded of everything down to the
bare rock. The eroding force must have been most powerful and long con-
tinued. As a rule, not only is all the decayed rock gone, but even the
crushed or loosened portions, leaving a smooth and sometimes polished surface,
well calculated to resist the denuding agencies of the present period. The
general form of the rocky domes which remain has been shaped by the same
force. The longer diameter of each, as a rule, is parallel to the direction of
the striation of the locality and the stoss or crag end is steeper than the tail
or lee extremity. The rock of the stoss side, which had been long exposed
to the stream of ice, like the upper side of a pier in a river, is more solid
and free from joints and flaws than that of the tail, showing deeper erosion.
In confirmation of this, it was found in constructing the Canadian Pacific
railway north and west of Lake Superior that it was more difficult to remove
rock on northward than southward slopes. The general bearing of the
striae gives us the line of the ice movement ; but it is not always safe to
assume that it came from the side indicated by any preconceived theory,
and we have in the above circumstances one of the best means of determin-
ing the actual direction from which the force came. Another guide to the
direction of the movement is this: The grooves are frequently found to radi-
ate, sometimes at considerable angles, on reaching a certain point, as on
meeting with some obstruction or with a change in the grade, especially when
tlye slope is steep. I have observed the same thing happen to previously

XXXIX— Bull. Geol. Soc. Am., Vol. 1, 1889.

296 R. BELL — GLACIAL PHENOMENA IN « \\\l>.\.

parallel grooves on their leaving a slight depression on such slopes. The
force would evidently come from the direction from which the grooves radi-
ate.

Perhaps the readiest means of ascertaining the direction of movement is
afforded by the crescent-shaped markings bo frequently to he Been on gla-
ciated surfaces, but which have nol received the consideration they deserve
in thi> connection. These markings follow each other at short intervals in
rowa parallel to the stria?, their convex sides being towards the quarter from
which the movement came These markings are generally from an inch to
sis inches in diameter. Wherever they occur they seem to indicate great
pressure and appear to have been caused by hard stones firmly held in the
lower surface of compact ice moving forward per aaltum, a< if they had
stopped at each interval and actually crushed into the rock-surface by the
stupendous weighl above, ami then to have been forced along again a short
distance when another Btop ami another bruise in the rock occurred.

When unaltered strata lie at low angles upon a nucleus of crystalline
rocks, there is :l marked difference in the effects produced by the action of
the passing ice-sheel according as the latter moved from the overlapping
Btrata onto thesolid nucleus or off the latter against the upturned edges of the
stratified rock-. In the former case no valley- are formed, and there is
oothing in the topography to indicate the junction of the two formations;
hut in the latter, great erosion has always taken place and valleys and
basins are formed whose width depends largely on the angle of dip and the
softness of the strata which have been scooped out. The strata are pre-
sented in the mosi favorable attitude for abrasion, especially when they
have been cracked by transverse anticlinals. The wearing-down pro,

Would go on till the resisting rock-front had attained a heighl and weight
sufficient to counterbalance those of the glacier. The excavating proa —
would be greatly aided by the tendency, which seem- to exist, of the rocky
del >ris to rise from the base over heights lying in front, in the direction of move-
ment. These excavations are now generally occupied by lake- or channels,

or they form valleys of liver.-. The St. Laurence helow Quebec, the North

channel of Lake Union, and the long sounds of the east Coast of Hudson's

bay are cases in point. The last named lie between the mainland ami the
long chains of islands which run parallel to it. The islands are composed
stratified rocks, dipping westward into the sea and having steep bluffs
facing inland or directly opposite to the general westward course of the
drift along that coast. The basins of lakes Ontario, Erie, Huron, ami
Michigan, as well a- that of Georgian bay, were excavated in a similar

manner. Further north we have other example- of ha-in.- of ero.-ioii in

lakes Winnipeg, Winnipegosis, Manitoba, Athabasca, and in Great Slave
lake, not to mention innumerable -mailer on< b.

LAKES FORMED BY GLACIAL ACTION. 297

The Formation of Lake Basins. — Some geologists seem to hesitate to admit
that the basins of the great lakes mentioned above could be formed in this
way, on account of their extensive areas and the great depth of some of
them. At the same time, they would probably not deny the glacial origin
of thousands of smaller lake basins, which can be pointed out in Canada,
where the whole evidence is presented to the eye in a very limited compass.
There we can see 'simultaneously glacial strise descending into the water on
one side of the lake-basin and emerging on the other, while more or less
drift material is deposited all around. Here we have no difficulty in realizing
the whole process of the formation of these small lakes. We have only to
enlarge our conceptions of nature to picture the formation of greater lakes
by the same process, which is equally easy on any scale, no matter how large,
if we can admit the forces to have been equal to the requirements ; and why
should we not? Why should we seek to limit the operations of Nature by
bounds set through our own narrow conceptions ?

Some lakes in the glaciated area, however, occupy sites of depressions
which existed loug before the drift period, and which may date far back in
geological time. These may have been greatly enlarged or partly re-
excavated by the action of the ice. Lakes Superior, Nipigon, Temiscaming
(on the Ottawa), and St. John (on the Saguenay) are examples of such ancient
geological depressions; but the grandest of all is Hudson's bay. The orig-
inal basins of all these bodies of water have existed since Cambrian and
Silurian or even earlier times. But there is abundant evidence of their
having been enlarged by glacial action. The site of Lake Superior appears
to have acted as a reservoir for the accumulation of ice, which again forced
itself out in different directions. Reference has already been made to the
fact that it moved westward from the northwest shore ; and it had a general
southward course for some distance from the south side. But the most
curious feature in this connection is the fact that it moved eastward, and
even northeastward, up the steep and rocky shores on the east side. Evi-
dence of this may be seen on mauy parts of the coast, all the way from
Michipicoten to Batchewana bay.

The wide but shallow basin of Hudson's bay is situated in the centre of
the greatest area of glaciation in North America, and it offers the most inter-
esting field for the study of the phenomena of the drift period, on account
of both the grandeur of the scale on which the forces operated and the
distinctness with which their records may be read at the present day. This
great central basin of the continent stretches from the interior of the Labra-
dor peninsula on the east to the Rocky Mountains on the west, and from
Baffinland on the north to Minnesota and Dakota on the south ; and it
has, therefore, a diameter of two thousand miles each way. As already
stated, the site of the present bay acted on a stupendous scale as a reservoir

298 K. I : I I I — GLACIAL PHENOMENA IN CANADA.

fur the snow-fall on its own area ami a- a collecting basin for the ice from
tin- Dorthwesl ami thi and discharged it in vast sheets to the northeast-

ward and the south ami southwest. The ice-sheet from this quarter would
he great enough to hold back the water of the hypothetical Lake A-gassiz,
although it is possible this may have heen supported by other means. The
teral elevation di' the land was probably greater than now, ami when the
ice melted towards the south, which it probably did rapidly, it may have
discharged a tremendous stream of water over what is now the narrow divide
between the head of Long lake and the north shore of Lake Superior. The
area of pot-holes, remarkable for their Dumber and great size, described by
Mr. Peter McKellar in a paper printed in thi- volume, is in the track which
would he followed by such a river.

Some extraordinary features with reference to glaciation are presented at
the northeastern extremity of Hudson's hay. The northern part of the easl
Coast of the hay runs about due north, while the western part of the south
>hore of Hudson's strait runs about due west, so that the two form a right
angle at ('ape Wblstenholme. Projecting westward from this cape are two
high islands, called Digges, the Outer one lying west of the Inner, the latter
being separated from the cape by a narrow notch. Overlooking Hudson's
.-trait from < 'ape Wolstenhplme, for twenty or thirty miles eastward, is a per-
pendicular precipice a thousand feet or more in height. It has a nearly uni-
form elevation: while, looking eastward from the Hudson's hay side, the
plateau above it has an even outline, which appears to slope slightly upward to
the brink of this great precipice. The angle formed between the south side

of Inner Digges and the main land is hounded hy high and almost perpen-
dicular walls of rock. The glacial movement here having heen from the
west ami south, it looks as if these walls had heen protected by a wedge »f
ice, their height having heen too great and their slopes too steep for the lower
part of the -lacier to surmount; while their peculiar conformation with
regard to each other would aid in wedging the ice in the manner supposed.
Ala considerable distance \<> the southeast, or directly inland from the cape,
-Hue mountains rise t" a height of perhaps a thousand feet above the plateau
which has just heen described. II' the ice-sheet moved from south to north
mi this plateau, B8 it did on lower lands to the southward, and if the laud

was a- high a- it i.- ai present, there must have been a magnificent ice-fall

over thi- precipice in glacial times.

The gnat lake.- of the St. Lawrence and our North west Territories are all

«.n or mar the junction of the Archean with newer rocks. The ha-in- "I

some of them extend far below the level of the sea, or even below the bottom
of Hudson's bay. Although this inland sea "I' Canada is Idled with -alt
water, it may, geologically Bpeaking, be considered as analogous t « * the great

lake- lather than a- forming part of t he ocean. With il- wide -hallow ha-in.

PREVALENCE AND EXTENT OF GLACIATED BASINS. ■J!>,.>

its eastern border of Azoic and its western of Paleozoic rocks, it bears con-
siderable resemblance to the vanished Lake Agassiz. If the Hudson's bay
region were raised bodily and evenly only about 400 feet, all its waters
would drain away, leaving an almost perfectly level plain unequalled for
extent in North America, and with the largest river in the world flowing
out at its northeastern angle ; but if it were canted so as to give a grade as
low as a single foot in the mile from north to south, it would separate from
Hudson's strait and become a gigantic fresh-water lake, discharging by the
continuous valley which follows the Albany and Kenogami rivers, Long lake,
and the Black river to Lake Superior, passing near the site of the cluster of
wonderful pot-holes described by Mr. McKellar. As the land was probably
much more elevated than this in the north during the glacial period and the
basin of Hudson's bay filled with fresh-water ice, it is not impossible that
towards the close of the period this ice became liquefied and that for a time
we really had a fresh-water lake larger than the present Hudson's bay. If
this were so, Lake Agassiz, large as it was, would be completely dwarfed
and Lake Superior, now the greatest lake in the world, would become a
mere pond in comparison.

The enormous glaciated Archeau region of Canada is preeminently the
land of lakes, and has no parallel in the world. Leaving out the great
border lakes already referred to, those within the limits vary in size from
170 miles in length, like Reindeer lake, down to a few hundred yards.
Among lakes from 40 or 50 to 100 miles in length may be named Aylmer,
Cree, North-lined, Wollaston or Hatchet, Reindeer, La Plonge, La Rouge,
Montreal, South Indian, Burntwood, Simon, Split, Sipi-wesk, God's, Island,
Trout, Lonely, St. Joseph or Osnaburgh, Rainy, Long, Temagami, Abittibi,
Teiniscaming, Keepawa, Grand, Nipissing, Mistassini, Michigama, and many
others whose names are entirely unknown to geography. Lakes of smaller
size count literally by the ten thousand. In some whole districts it is esti-
mated that nearly one-half and certainly one-fourth of the entire area is
occupied by these sheets of water. They are nearly all rock-basins, com-
paratively few of them being held in by moraines or loose material in any
form. They often run in chains or systems, in different courses, thus forming
canoe-routes by which one may travel in almost any desired direction. The
lakes constituting these chains often discharge into one another by a suc-
cession of short links of river. The upper Ottawa, the English river, which
discharges Lonely lake into the Winnipeg, and the Churchill from its source
to where it enters upon the Paleozoic rocks, are among the examples of these
chains of alternating lake and river.

Reaction of Rock Structure on Glacial Erosion.— The arrangement of the
lakes in the patterns above referred to is due, originally, to glaciatiou in
connection with preexisting geological causes. Among these may be men-

.".mi K. BELL — GLACIAL PHENOMENA IN CANADA.

tioned the dips and flexures of the strata, lines ol crushing or fissures, with
or without igneous injections, and unequal hardness of the rock — <>r rather
its unequal susceptibility to decay. I have often noticed that lines of
crushing which might nol otherwise have been very observable are of much
importance in promoting the decay of the rock, preparatory to it- removal
by glacial denudation, the differenl Btages of the process being observable
iu the northern regions. The influence of dikes of breccia, trap, syenite,

etc., in inection with erosion has been very considerable in determining

the topography. The large and small dikes have frequently produced oppo-
site effects. The former, being coarsely crystalline and decaying easily, have
given rise to long valleys, now occupied by rivers or lakes, while the smaller
one-, being close-grained, tough, and generally resisting disintegration well,
have protected other rocks from the force of the glaciers, and they are now
marked by ridges or by the chutes and falls which they cause in the rivers
crossing their courses.

The effeel of large dikes in thus producing channels for water is very
conspicuous in some sections of the Mattagami river, as described in my
Geological Survey report for 1875. In my report for l's7<> I pointed out
that the trough of Long lake, more than fifty miles in length and running
a! right angles to the strike of the crystalline rocks of the region, lies along
the course of an Immense dike, [n 1878 the long, straighl channel of Nelson
river, from Bipi-wesk to Split lake, was shown to he due to a similar cau.-e.
Anion- other long sheets of water which have been excavated upon the run
of large dikes may he mentioned < >ha lake, north of Michipicoten ; Poga-
masing lake, mar the intersection of the main line of the Canadian Pacific
railway ami the Spanish river; Onaping lake, a narrow channel thirty miles
long, lying north of a station of the same name on the railway just men-
tioned; ami Matatchewan lake, at the great bend of Montreal river. And

I have no doubl that almost all tin' lakes of this Arehean region which are
tolerably straighl and \-i\y long in proportion to their breadth will !>■■ Pound
to occupy channel- originally due to the existence of large dikes. Among
-mli lakefi may \»- named the Long lake, west of Lake of the \Y I-. and

Lake Temiscaming on the Ottawa. The gorge of the Sagnenay, and even
that of Hudson's strait, may be due to similar causes. The narrow rocky
arm ol ' ian hay which receives the Maganatwan river is situated upon a

rift iu the gneiss, filled in places with breccia, resulting perhaps from the grind-
in"- of its wall-. It is probable that similar inlets in the vicinity, such as Col-
line inlet, The Key, ami the peculiarly straight intersecting channel- of the
mouth of tin- French river, originated in Bimilar fissures. M r. E. B. Borron, J.
P., w ho has travelled much in the regions north of lakes Huron and Superior,
inform- us that he ha- 31 . n 30 many instances confirming the above \ iew as
to the origin of straighl river-courses and long narrow lakes that he regards
ii j- mi . stablished lad in regard to the topography of the country.

LAKE TEMAGAMI AND ITS FOUR EFFLUENTS. 301

Lakes of Double Outlet. — The -widespread Archean area of Canada, having
nearly everywhere about the same general elevation, is naturally divided
into many hydrographic basins. The water-sheds separating them are not
well defined ridges but plateaus with such gentle slopes that it is often diffi-
cult to tell which side of the height of land one may be on, and there is an
interlocking of the upper waters of rivers which flow to opposite sides. The
country along these divides is so level and the streams are so sluggish that
all the brooks are navigable by canoes. Lakes of various sizes, some of
them being of the larger class, occupy these situations, and not infrequently
they have two outlets discharging their waters in opposite directions. This
condition could only happen in rock-basins where but little wear is possible;
for if the outlets were over soft materials one of them would soon become
deepened and the other would cease to flow. Among the more striking ex-
amples of this phenomenon which might be mentioned are the following :
Wollaston or Hatchet lake, which sends out two rivers of equal size and
each larger than the Mississippi at St. Paul, the one falling into Lake Atha-
basca and the other into Reindeer lake — that is to say, into the basins of
Mackenzie river and Hudson's bay respectively ; Summit lake, between Lake
Nipigon and Albany river, which discharges equal-sized rivers northward
by the Albany into Hudson's bay and southward by Lake Nipigon into the
St. Lawrence. These streams are navigable without interruption for small
boats for miles on either side of the lake, so that one may sail up one, through
Summit lake and down the other without getting out of his craft.* In 1887
I passed through no fewer than five lakes with double outlets connected with
different branches of the upper Ottawa between Lake Temiscaming and the
source of the river.

The most remarkable instance of a lake with more than one outlet which
I have met with is that of Lake Temagami, between Lake Nipissing and
Montreal river. We have made a careful detailed survey of this beautiful
sheet of water. It measures about thirty miles from north to south and the
same from east to west, and has had until recently no fewer than four out-
lets, one towards each of the cardinal points. The east and west outlets
have dried up, either from the deepening of the other two or from a very
slight elevation on either side of the north and south axis of the lake. Some
time ago the northern outlet was evidently the larger of the two yet running ;
but it is now smaller than the southern, and appears to be still diminishing,
while the other is correspondingly increasing. This may be due to an ex-
tremely slight tilting in the surface of the country. A rise of a few feet in
the water of the lake would set all four outlets flowing again.

Discordant Strice. — In regard to the courses followed by the glaciers of the
drift period, when the directions of the strise in all parts of the country are

* Report of Progress, Geol. Survey of Canada for 1871-72, page 107.

302 R. BELL — GLACIAL PHENOMENA IN CANADA.

laid down upon :i map, some degree of parallelism is shown within the various
groups, yel the general bearings of these are bo different thai it is difficult
to s«e how they could have all been produced contemporaneously or by a
confluent ice-sheet : and yet, excepting far to the north, they all seem to be
equally old, and to have the same relations to the till. If any great interval
of time had elapsed between the production of these various Bets of grooves
we Bhould see greater differences among them than we do. A satisfactory
solution 'it' the problem requires more study than it has yet received, hut it
seems possible that the different groups, nearly equally distant from the
margin of the glaciated area, may have been produced within a few thousand
years of eacli other, their varying directions being accounted for by changes
in the slope of the land and by the greater or less quantity of ice existing
at the time — the course of a deep and wide glacier influenced by the general
contour of the country being different from that of a narrower one guided
by the more local features. In this way nearly all the grooves which had
been produced in a given region might he obliterated and replaced by another
Bet within a comparatively short time, leaving only traces of the earlier ones
behind. It would not, therefore, he necessary to suppose two distinct glacial
periods to account for such facts.

Such changes in the direction of transportation would also serve to explain
some of the facts in connection with the composition of the drift. In order
to trace the distribution of the latter we require to choose some rock of a
well-marked character, situated far enough north, whose position ami bound-
aries are known. The peculiar and beautiful conglomerate of white quartzite
matrix with red jasper pebbles which occurs, BO far as we are aware, only
at the east end of Lake Superior and in the adjacent country north of Lake
Huron affords one of the best examples of this sort. Fragments of this
rock are found to the eastward all along the northern shores of Lake Huron

a- far as French river, although the direction of the striae in the interval ami

all around the northern part of Georgian bay 18 "SOUthwest. Worn pieces of
the same rock have Keen met with in the counties of Bruce and Huron, ami
Bouthward through the state of Ohio ami into Kentucky. A large bowlder
of this conglomerate, found in the southern part of the lower peninsula of
Michigan, bas been placed in the grounds of the State University at Ann
Arbor. This wide lateral dispersion from a small center and partly aw
the direction of the existing striae implies a shifting of t he drift materials by
successive glaciers pursuing different coursi

Lakt Agasriz. Lei us now turn our attention for a few moments to Lake

\ .-i--i/. 'I'll-- writer, having explored pretty extensively in the country

between the site of this former lake and Hudson's bay, which is the mosl

interesting field of inquiry in connection with questions :i- to the possibility

of the existence of such a lake, may he allowed to add some remarks to

POSSIBLE BARRIEB OP LAKE AGASSIZ. 303

what has already been said on this subject. It has been assumed by some
geologists that, owing to the supposed lowness of the land, the front of a very
wide glacier would be requisite in order that the water of this lake might have
been sustained on the east; but no actual evidence has been offered, except
by myself, that any glacier ever existed in that quarter. Although it would
appear that the ice-sheet did at one time push its way from the bed of
Hudson's bay, or even from the high lands of the Labrador peninsula to
the east of it, across the intervening country, this agency may not have been
necessary to account for the existence of the lake. The gap which would
require to be stopped in order to dam up the water and cause it to spread
over the shallow basin of Lake Agassiz is much narrower than is commonly
imagined. Without supposing any change of levels, the water-shed between
Lake Winnipeg and Hudson's bay is more than sufficiently high to retain
the water till it comes within a very short distance of Nelson river. Then
on the northwest side of this great stream the land rises rapidly below the
junction of Burntwood river to a height of at least 500 feet above the main
stream, and the Churchill flows in a valley much more elevated than that of
the Nelson.

Great quantities of moraine matter are deposited on the western slope of
Hudson's bay on all the routes which I have followed in travelling to it from
the interior. It forms hills and ridges, through which the rivers have cut
their way. Hill river, on the travelled route between Lake Winnipeg and
York Factory, is so called from Brassy hill, a steep, conical mound of earth
in the line of a great moraine, which rises to a height of 390 feet above the
water at its base, where it is intersected by the river. This is, perhaps,
higher than the level of Lake Winnipeg. From the top of this hill about
twenty moraine lakes may be counted.

This paper is already too loug, or many interesting facts might be given
in reference to the intersection on other rivers of what may be the continua-
tion of this moraine. But, judging from what I have seen on my own ex-
plorations and from what I have been told by local travellers, I may simply
say it seems probable that a great terminal moraine may be traced along
the western slope of Hudson's bay at a considerable distance inland and with
an elevation of several hundred feet above the present level of its water. It
is possible that at one time part of this moraine choked up the valley of
. Nelson river and flooded back the water of the Winnipeg basin so as to form
Lake Agassiz. This would be rendered all the easier if the continent were
slightly more elevated to the eastward than it is at present, and there is
much reason for believing that it was so. The well-marked beaches of
Lake Agassiz show that its waters were stationary at certain levels for a con-
siderable time, wdiich could scarcely be possible if its outlet were through or

XL— Bull. Geol. Soc. Am., Vol. 1, 1889.

304 I:. BELL — GLACIAL PHENOMENA IN CANADA.

over a glacier. There are various other strong objections to the theory of
an ice dam, which cannoi be discussed within the limits of this paper.

If, on proper investigation, it should turn out unlikely that the water of
Lake Asassiz was held in its place by earth barriers in conjunction with a
higher general level of the continent to the east, then we shall probably find
that this ancient lake was a land-locked hay of fresh or nearly fresh water
on the Bame level as the former extension of Hudson's hay. Had the conti-
nent been Blightly elevated to the eastward, and had the north end of Hudson's
bay at that time been about 1,000 feet higher than at present, relatively to
the narrow divide between Long lake and Lake Superior 1,0(10 miles to the
smith, the fresh water which we have supposed would then fill this great
basin might easily have been on the same level with Lake Agassiz, and the
latter would then have been a mere hay of the former. A whitish clay of
similar character i- spread widely over both areas : and it is significant that
no marine shells are to be found in any of the post-Tertiary deposits in either
of these area- until we have descended to within 500 feet of the sea-level on
the Attawapishkal river, and 200 feet lower on the various branches of the
Moose river at a distance of 200 miles to the south. The shells are found in
similar stratigraphical positions in both cases, and their difference in level
corresponds with the rate of slope (one foot in the mile) which would exist
had the supposed relative change of levels occurred.

Upward Movement of Bowlders. — The elevation of bowlders from lower to
higher levels is a curious phenomenon in connection with drift transporta-
tion. In the lake peninsula of the province of Ontario, the debris of the
Hudson River and Niagara formations has been carried westward in great
quantities and scattered over the surface of rocks which are higher both
geologically ami geographically. In the valley leading westward from the
head of Lake Ontario, the ice-grooves are plainly seen on the rocky walls
on either side sloping gradually upward; but to the north of this valley
there i- an almost continuous east-facing precipice all the way to Georgian
bay, which the ice-sheet would require to surmount. The Silurian table-land
above this precipice slopes gradually upward, as we go north, from about
•101) feet above Lake Ontario tO Upwards of 1,500 feet over the s:une level

when it reaches Georgian bay and forms the Blue Mountains. Laurentian

bowlders, from the comparatively low region north of Georgian bay, are
found everywhere upon this table land.

In the chapter on superficial geology in the "Geology of Canada" (1863,
page 894 . I Btated, from my own observations, that "bowlders of Lauren-
tian rock- are found in considerable numbers scattered over the high table-
land of western Canada south of Georgian buy. A portion of this region
attains an elevation of 1,7<'»<» feet above the sea, and much of it is higher

than the Laurentide hills, to the north, from which the bowlders have been

BOWLDERS PERCHED ON AN ESCARPMENT. 305

derived. These blocks are generally more angular than those from a simi-
lar source found at lower levels, and are associated with many others of local
origin."

In approaching the base of the Niagara escarpment anywhere from Lake
Ontario to Georgian bay, or along its continuation to the northwestward
through the Indian peninsula and the Manitoulin islands, one cannot fail to
remark the absence of any considerable talus or accumulation of the waste
of the former extension of the strata composing the cliff. The fallen blocks,
except the most recent ones, have all disappeared, and we find them perched
up on the brink or scattered on the plateau above it, instead of strewn over
the lower lands at its foot, where we might have naturally looked for them.
On the west side of Lakes Manitoba and Winnipegosis an east-facing escarp-
ment of nearly horizontal Cretaceous strata rises to a height of about a thou-
sand feet in the form of the Riding and Duck mountains. The table-land
of these mountains is, in many parts, strewn with Laurentian bowlders de-
rived from the lower-lying Archean region east and northeast of Lake Win-
nipeg, showing a great uplifting of the erratics by the glacier-sheet. The
bowlders are occasionally deposited in ridges and hummocks, some of which
are mentioned in my report for 1874.

In the report for 1873 on the Northwest Territory, I showed that the drift
of the country between the Laurentian region and the Coteau de Missouri
came from the northeastward, and that it consists of " Laurentian gneiss,
granite, syenite, and the crystalline schists of the Huronian series, together
with a large proportion of compact, buff, drab, and gray limestone;" also
that the front of the Coteau itself " consists in reality of the ruins of an
escarpment;" aud that "the force which had undermined it had evidently
acted from the northeastward." The high ground of the Coteau was fur-
ther described as very rough and covered with the above kind of drift.
Many of the Laurentian bowlders are angular, and they "are so numerous
over considerable areas that a man might walk upon them in any direction
without touching the ground." * The front of the Coteau was ascertained
by barometer to rise from (300 to 700 feet above the plain immediately to
the north of it. The hills of drift above the Coteau are steep and gener-
ally conical, and resemble, on a grand scale, the appearance of stiff stony
earth newly dumped in separate piles close together. The hollows between
these hills contain numerous ponds and small lakes. As the foot of the
Coteau is probably as high as the average of the Laurentian surface to
the northeast, if not higher, the ice-sheet must have been able to elevate this
vast quantity of drift to the above heights.

The angular character of many of the bowlders which have been raised
to the various elevated areas just described is an interesting tact, and it

* Rep. of Progress Geol. Surv. Can. for 1873, 1874-75, page 43.

306 R. BELL — GLACIAL PHENOMENA IN CANADA.

seem:- to indicate thai these bowlders have been carried either in the midst
of the ice or on the back of the glacier, which they must have reached by
passing upward through its substance by Borne process which has not yel
been clearly demonstrated.

I noticed thai where the supposed great terminal moraine of the western
slope of Hudson's bay is crossed by the Churchill, Little Churchill, Nelson,
and Hill rivers, ;i large proportion of the bowlders were angular. This ap-
peared to be more especially the case on Hill river, where the stream flows
for miles on a bed of angular Laurentian bowlders in the section which
traverses the supposed moraine.

Thi Period of Glaciation. — [n attempting to estimate the time which has
elapsed since the glacial period, everyone is struck by the freshness of the
striae on many glaciated surfaces, and might argue from such evidence that
this period was nol so remote as most geologists have hitherto supposed. It
will be found, however, thai most of the well-preserved surfaces have been
protected from the weather during the greater part of the time that has
elapsed, either by water, which has since disappeared but of which we see
bo much evidence, or by earth which has recently been removed. Even the
water- of the presenl lake- and river.- have a great effect in preserving the
striae. In the Laurentian lake.- they are wonderfully sharp and distinct
under the low-water mark, whereas the continuations of the same grooves on
exposed surfaces are almost obliterated, although the hard and smoother

surfaces of the glaciated rocks are well calculated to withstand the influem

of time. < )n unaltered rocks which have been long exposed the ice-grooves
are entirely gone, and the surfaces which we know by their outline mu.-t
have been glaciated are crumbled or eroded.

In thee ty of A.rgenteuil, Sir William Logan described veins of quartz

cutting crystalline limestone where the striated surfaces of the former stand
out from -i\ to nine inches above the general surface of the latter, showing
that the limestone ha- been dissolved away to that depth since the striation
took place; hut thi- may have all been done during onlyapart of this
interval. I have seen many other cases both in Argenteuil and Ottawa
counties where hard veins ami lump- embedded iii crystalline limestone and
bearing the striae are weathered out to various heights not exceeding one
fool above the roughened but Bound Burf'ace of the limestone.

After all, the surface of any -ton,- hard enough to be used in the building

of important -tincture- withstands the influence of the weather for long

periods, as proved by many example- in Italy, Greece, and Palestine, and
more particularly in JSgypI and Central America. A smooth and Bound
rock-surface produced l>\ glacial rubbing and polishing is better adapted to
endure the ravages of time than any artificially hammered surface. The
destructive influences of time appear to operate even more -lowly in cold

DURABILITY OF GLACIATED SURFACES. 307

regions thau elsewhere. Oxidation and decay of all kinds are slower than
under the influence of heat and the rapid growth of all the various lower
forms of plant and animal life. Not only are marks on rocks preserved in an
extraordinary manner in northern climates, but the great durability of timber
has been remarked by travellers in Norway and the Arctic regions of
Canada. Logs of such perishable wood as spruce, which even in this lati-
tude would disappear through decay in a few years, are found in a sound
state in the latter regions, where they have probably lain for thousands of
years. Even on the east coast of Hudson's bay I have recorded the occur-
rence of lines of drift-wood, principally spruce and cedar, on raised beaches
thirty feet above the highest tides, which would indicate a period of over
400 years, even if the rate of elevation were as rapid as my supposition of
seven feet in a century.

The deposition of the thick sheets of till over the well-preserved grooved
surfaces at any given place could not have been quite contemporaneous with
the making of the grooves themselves, but must have required time. Again,
we should take into consideration the many things requiring great length
of time which have taken place since the till was left upon the surface of
the rocks, such as the submergence of the land and the deposition of various
stratified clay and sand formations upon it. At Ha-ha bay, on the Sague-
nay, the stratified clay of the Champlain formation, which overlies the drift,
has a thickness of upwards of 600 feet ; and in the valley at the head of Lake
Ontario the clay above the till is at least 200 and may be 400 feet thick.
The stratified gravels and sands of Burlington heights at this locality rise
107 feet above the lake, and are also sunk below it. These deposits lie upon
the stratified blue clay of the Erie formation, which in turn rests upon the
till.

We cannot suppose that the change from the glacial condition to some-
thing like the present climate of North America was a sudden one. The
transition, whether brought about by astronomical causes or only from
changes in the elevation and distribution of the land and in the currents of
the ocean, must have been very slow. It is therefore very improbable that
the ice disappeared from all parts of the continent at the same time. There
must have been a gradual and progressive recession northward of the general
glacial condition, which may not yet have entirely ceased. Glaciers are
said to exist still in some parts of Baflinlaud. It is, however, more probable
that we have passed the period of greatest warmth, and that a colder con-
dition has again begun to creep upon us from the north. The continued
elevation in polar regions, historical facts in Greenland, the southward
retreat of the verge of the forests, and other circumstances favor this view.

Southward of the central regions of dispersion it may be assumed in a
general way that the time which has elapsed since the disappearance of the

308 R. BELL — GLACIAL PHENOMENA IN CANADA.

ice at any locality varies to a great extent with its latitude, so that 1 1 » * - an-
tiquity of the glacial groovings and drift deposits of the district between
Pennsylvania and Nebraska in the south and those of the latitude of the
center of Hudson's bay in the uorth may and probably does differ by many
thousands of years. In order to attempt some kind of calculation of time
based on a given rate of recession of the ice-sheet for this distance, let us for
the moment Bet aside all other questions that might complicate the problem
and try to obtain some idea as to bow long it might take li>r the simple and
direct recession of the ice, say from the Latitude of Cincinnati to that of the
most southern glaciers of Baffinland. Cincinnati is in latitude 39° and the
reputed glaciers of Baffioland in about 65°, a difference of twenty-six degr<
If the average retreat of the ice sheet was as rapid as one degree in a thou-
sand years, which is probably above the mark, it would require 26,000 years
to need'' from its southern limits to the regions where the glacial condition
is possible at this day.

On Portland promontory on the east coast of Hudson's hay, in latitude
3 , and southward the high rocky hills arc completely glaciated and hare.
The striae arc as fresh-looking as if the ice had left them only yesterday.
When the sun hursts upon these hills alter they have been we1 by the rain
they glitter and shine like the tinned roofeof the city of Montreal. Yet even
here it must have been a good many thousand years since the glaciers dis-
appeared.

In my report for 1884 I described the occurrence of the handiwork of the
Eskimos on Outer Diggee island, indicating a lapse of at least one thousand
years: and still the time which has gone by since these people built their
dwellings and their .-tone fish-traps on the beaches then washed by the sea,
but now ehvated seventy or eighty feet above it> level, must have been
short compared with the days when great ice-sheets from the interior slid
down the rocky slopes on the foot of which these beaches lie.

The nee.— ion and disappearance of the ice-sheet is, bowever, only one of
the elements to be taken into account in trying to arrive at some estimate
of the time which bas elapsed since the deposition of the till along its south-
ern extension. We have to consider the submergence and elevation of the
land which followed. These movements are extremely bIow, and would re-
quire at leas! double the above time, or over 50,000 vears, for their accom-
plishment. At Naelivak. on the eastern coast of Labrador, raised beaches
.-how with great distinctness at an elevation of aboul 1,500 feet above the
-. ;i. The land might have been 2,000 feet higher than at present at the time
of the greatest accumulation of ice. This would represent a depression oi
3,500 feet and a subsequent elevation of 1,500 feet. If the rate of vertical
movement w<\>- as rapid as -even feel pi r century, the depression aud eleva-
tion proved by the existence of these beaches would require upwards of

PHYSICAL CONDITIONS OF THE GLACIAL PERIOD. 300

42,000 years ; but it was probably much slower than this on an average ami
there must have been a long stationary period when these beaches were
forming, so that the estimate of Dr. James Croll, Dr. James Geikie and
others of 80,000 years as the time which has elapsed since the glacial period
in Great Britain and the inhabited parts of North America need not be con-
sidered excessive.

The Cause of Glaciation. — In regard to the formation of the vast quanti-
ties of land-ice of the glacial period, it is a common error to suppose that its
accumulation was due to intense cold alone. The production of glaciers was
due to the same causes then as now, namely, a warm ocean with high land
so situated that the air coming from the water laden with moisture might pass
over the cold land and precipitate the vapor upon it in the form of snow.
There is reason for believing that the Laurentian area of Canada and the
northern part of the Appalachian region were much higher in the glacial
period than now. The great precipitation of snow which took place over
these areas may have been due to an extension at that time of the Gulf of
Mexico over part of the Mississippi valley. The Gulf Stream, perhaps of
greater volume then than now, would eddy round the enlarged Gulf, giving
an immense evaporating surface, and, passing round the southern part of the
Appalachian range, would flow northwestward close to this continent, being
protected from the Arctic current by the dry land which would take the
place of the now submerged banks of Newfoundland. If the weather circles
or ellipses travelled in courses corresponding to those which prevail at the
present time, we should thus have the most favorable conditions for the
rapid accumulation of ice all over the area which has been glaciated.

The Causes of Changes in Level. — What caused the depression of the land
at the close of the drift period ? The suggestion that it may have been due
to the weight of the ice itself bending down the crust of the earth is worthy
of consideration, although this explanation would be more obvious had the
depression taken place while the weight was upon it, and not after its
removal. The subsequent elevation, which is still going on, may be the
slow return of the outline of this part of the earth's surface to its normal
curve. It is generally accepted that ice acts as a semi-fluid, and therefore
it must be subject to hydrostatic laws. Many facts in geology go to show
that rocks, too, on a large scale have manifested a sort of plasticity without
having undergone igneous softening. May not the whole globe of the earth
slowly follow these laws, even if its interior be not in a liquid condition?
The slightest sensible pressure on any part of its surface would be followed
by an effort to regain its perfect equilibrium. But the elevation of the land
above the general level of the ocean, which is still in progress in north polar
regions, may be something more than a mere upheaval of part of the crust
of the earth. It may be, as Dr. Croll supposed, an actual retiring of the

310 R. BELL — GLACIAL PHENOMENA IN CANADA.

Bea, due to a slight shifting of the centre of gravity of the earth on account
of the accumulation around the south pole of the mass of ice, a mile thick
and 2,000 miles in diameter, which is believed to exist there. In the north-
ern portions of America, along with this general movement, local elevations
ami depressions may also he going on. Bui the evidence of the numerous
Arctic voyagers who have visited nearly all parts of the northern regions of
the Dominion shows that this movement is taking place with apparent
uniformity throughout this large area of the earth's surface.

Towards the close of' the period of depression following the glacial era, the
northern parts of lakes Huron and Superior must have heen relatively lower
than the southern in order to account for the well-marked terraces and
beaches which we find at various elevations up to more than 300 feet above
the levels of their present outlets, as there is no evidence of harriers of any
kind having existed in their neighborhoods in such recent times. The Dav-
enport ridge behind Toronto, and gravel ridges at the head of Lake Ontario,
prove that its waters stood at least 17<> feet higher than now at some time
since the glacial period; and, as there are no remains of a harrier at its east
end, it is probable that the bed of the St. Lawrence below it was so elevated
as to keep hack the waters to this additional depth. The evidence thus
afforded by some of the great lakes of the St. Lawrence goes to confirm the
theory of a former depression and subsequent elevation of the continent
towards the north and east.

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA

Vol. 1, pp. 311-334

ON THE PLEISTOCENE FLORA OF CANADA

Sir WILLIAM DAWSON, F. G. S.,

AND

Professor D. P. PENHALLOW, F. R. S. C.

WASHINGTON
PUBLISHED BY THE SOCIETY

April, 1890

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA
Vol. 1, pp. 311-334 April 9, 1890

ON THE PLEISTOCENE FLORA OF CANADA.

BY SIR WILLIAM DAWSON, P. R. S., AND PROFESSOR D. P. PENHALLOW, F. R.S. C.
(Read by abstract before the Society December 28, 1889.)

CONTENTS.

Page.

I. Geology of the Deposits. By Sir William Dawson 311

General Geology of the Pleistocene.,' 311

Special Localities of Fossil Plants 316

Geographical and Climatal Conditions , 318

II. Notes on the Pleistocene Plants. By D. P. Penhallow 321

Annotated List of Canadian Plants 321

Description of New Species 327

Kevision of previously recorded Pleistocene Plants 329

Lignites 332

Woods from Illinois :::;::

Synopsis 333

I. GEOLOGY OF THE DEPOSITS. BY SIR WM. DAWSOX.

General Geology of the Pleistocene.

The Pleistocene deposits of Canada may be defined as consisting of three
principal members, which may be characterized as follows, in ascending
order :

1. The Till, or lower bowlder clay, a tough or sometimes sandy clay,
containing local and traveled stones and bowlders, often glaciated. It
usually rests on glaciated surfaces, but is sometimes underlain by stratified
gravels or by old soil surfaces or peaty beds. These are, however, rare and
local.* In the more maritime regions — e. g., in the lower St. Lawrenc( — it
contains marine shells of arctic species. Farther inland — c. </., in western
Ontario and in the plains west of Red river — it is not known to hold marine
remains.

2. Stratified clays and sandy clays. In the more maritime regions these
are the lower and upper Leda clays, holding many marine shells of boreal
rather than arctic types, especially in the upper part. They also contain
locally, drift plants, insects, and land or fresh-water shells, indicating the

♦Acadian Geology, 1878, p. 03.
XLI— Bum.. Geol. Soc. Am., Vol. 1, 1889. (31 [)

312 DAWSON A.ND PENHALLOW — PLEISTOCENE FLORA.

proximity of land clothed with vegetation. In the interior they are, bo far
as known, destitute of marine remains, but hold remains of land plants and
even beds of peat with a few fresh-water shells. These beds are those known

in the interior region as " interglacial." They Mem to vary much Locally
in composition and thickness, and are sometimes absent Where they are
absent or replaced by bowlder clay, the latter occasionally contains drift
trunks and branches of trees.

3. Sand-, coarse day-, and gravels, often stratified, sometimes ( taining

traveled bowlders throughout. In other eases there are bowlders at the
base of the deposit and also at its Burface, the intervening beds being destitute
of bowlders. In the maritime regions these beds often contain marine shells
and are the Saxbeava Bands and gravels. Inland they are unfossiliferous or
have a tew drift plants, sometimes of sufficient importance to he reckoned as
a Becond or upper interglacial bed. These beds constitute the upper or
newer bowlder formation. Their traveled bowlders are often of ^reat size,
and have been as a whole carried farther and deposited at higher levels than
those of the older bowlder formation.

Above the third member are alluvial deposits, lake terraoes, gravel ridges
ami eskers, prairie silt, peat beds, etc., which may he regarded as early
modern or post-( ilaeial.

More detailed descriptions of the Pleistocene deposits of Canada will be

found in the author's " Notes on the Post-Pliocene of Canada : " :; also in his
" Acadian ( Seology " and " Handbook of Canadian ( reology."1

Fossil plants appear in these deposits in various places, from the Atlantic
coast to the base of the Rocky Mountains and even in Queen Charlotte's
islands; but the Bpeciea are not numerous, and for the most part those now
indigenous to the boreal regions of America, while their state of preservation
is usually very imperfect.

A- might be expected, vegetable remain.- in the Pleistocene an' not con-
fined to Canada, but occur very extensively in the United States. Whittle-

. Worth en, Andrews, Orton, Newberry, and others have referred to
deposits of this kind in Illinois, Indiana. < )hio. and Minnesota : and in the
"Proceedings of the American Association" for 1875 Professor N. II.
Winchell has Bummed up what was known up to that date, and has noticed
more than fifty localities of the " forest beds," as these accumulations are
called. Professor Worthen has recognized two distinct forest bed- in Illinois,

One immediately below the loeSB, the other under till or true bowlder clay.

The latter he says extends over nearly the whole of central and southern
Illinois. Though I have had specimens kindly sent to me by Professor
Worthen, Dr. Andrews, and others,] do not propose to enter into any details
on these deposits in the United State-, but merely to referto their extension
from Canada to the southward as important in a geological sen

VI, 1871, p. 11 t Montreal, i

SECTIONS OF PLEISTOCENE DEPOSITS.

313

The observed sequence of deposits may be understood by the subjoined
sections, which represent respectively the arrangement in the St. Lawrence
valley at and below Montreal as observed by the author ; that on the north
shore of Lake Ontario as given by Dr. J. G. Hinde ;* and that in the vicinity
of the Belly river, North West Territory, as noted by Dr. G. M. Dawson.f

Montreal and lower St.

Lawrence.

J. Wm. Dawson.

o
o
o

Surface soil, post-Gla-
cial alluvia and peat.

II.

Surface bowlders, Saxi-
cava sand and gravel.
Bowlders in and below
sand.

III.

Upper Lcda. clay, ma-
rine shells, and drift
plants. Lower Leda clay,
marine shells, and drift
plants.

IV.

Lower bowlder clay or
till. Many native and
some traveled bowlders.
A few marine shells of
arctic species.

Paleozoic rocks,

striated.

often

North shore of
Ontario.
J. G. Hinde.

Lake

Surface soil, stratified
sand, and gravel.

II.

Bowlders, sand, etc.
Laminated clay. Bowl-
der deposit.

III.

Stratified sand and
clay, with fresh-water
shells and plants.

IV.

Lower bowlder clay or
till. Native and traveled
bowlders.

Paleozoic rocks, often
striated.

Belly river, North

Territory.

G. M. Dawson

West

Surface soil and prairie

alluvium.

II.

Upper bowlder deposit.

III.

Gray sand with iron-
stone nodules. Brownish
sandy clay. Carbonaceous
layers and peat. Gray
sand and ironstone.

IV.

Lower bowlder clay.
Many traveled bowlders.

Probably Cretaceous
beds.

The above sections show a general correspondence in the series of deposits,
except that in the sections on Lake Ontario, especially in that at Scarboro'
heights studied by Hinde, we find a division of the upper bowlder deposit
not so evident in the other sections.

There is no reason to doubt that the three members of the Pleistocene
indicated as II, III, and IV are approximately contemporaneous in the
different districts, and that No. Ill represents the usual interglacial period
throughout North America. At the same time it is to be observed I 1) that

* Canadian Journal, 1877, p. 339, et seq. t Keport Geol. Survey of Canada, L884, p. 1 1 1 O, et seq.

314 DAWSON ami PENHALLOW — PLEISTOCENE FLORA.

these deposits occur al different levels in the East and in the West ; (2) that
the lower howltler clay belongs more especially to the lower levels in the
several localities, while the howhlers of the second bowlder period have been
carried to higher points; (3) that there is evidence in the interglacial period
of the local prevalence of sea and land, of lakes, bogs, and dry ground ; (4)
that these several conditions may in the course of elevation and subsidence
have migrated from one level to another, and (5) that while there is thus
a general correspondence, there may have been some local diversity of date
and transference of certain conditions of deposit from one locality to another
according to the progress of subsidence or elevation.

This is so well illustrated by the observations of Captain Fielden in
Grinnell Land, that I quote a part of his statements on the subject, as
probably illustrative of the condition of Canada in the Pleistocene period.*

" In Grinnell Land, from lat. 81° 40' N. to hit. 83° G' N\, no glaciers descend to
the sea, no ice-c:tp buries the land ; valleys from which the snow is in a great measure
thawed during July and part of August Stretch inland for many miles, and the peaked
mountains, snow-clad during the greater portion of the year, in July and August have
great portions of their flanks, which rise to an altitude of 2,000 feet, bared of snow.

"The opposite coast of Greenland presents a very different aspect. A mer-de-glace
stretches over nearly its entire surface; its fiords are the outlets by which its great
glaciers protrude into the sea. In Petermann Fiord the ice-cap, with its blue jagged
edge lying Hush with the face of the lofty cliffs, was estimated to be forty feet thick.

'; When we turn to the flora and fauna of Grinnell Land the difference is equally
astonishing; some flfty or sixty flowering plants are found in its valley-, and between
latitudes 82° and 83° N. I have seen tracts of land so profusely decked with the
blossoms of Saxifraga opporitifolia that the purple glow of our heath-clad moors was
brought to my recollection.

;i .Musk oxen in considerable numbers frequent its shores ; the Arctic fox, the wolf,
and ermine, with thousands of lemmings, live and die there. The bones of thesn
mammals, along with those of the ringed seal (Phoea hispida), are now being

deposited ii nsiderable quantities in the fluvio-marine beds now forming in the baj -

and at the outlets of all the streams, or rather summer torrents of Grinnell Land.
With these bonea will !»■ associated those of birds, such a- geese ami Bea-gulls.
Numerous mollusca and Crustacea, many species of rhizopods, with the remain- of
land and sea plant-, will there And a resting place.

"Supposing that these beds were examined at Bomo future period under conditions
when the glacial epoch had disappeared from tie- surrounding area, it would i„. difficult
to realize that they were contemporaneous with the bed- formed under the Greenland
ice-cap in the Bame parallel of latitude and on the opposite shore of a channel nol
twenty mile- across.

■■ In tin' on. ormouB thicknesses of till with ice-Bcratched stonea have in all

probability been deposited ; in the other, fluvio-marine bed- containing a compara-
tively rich assemblage Of marine ami land form-, with river-rolled pebbles, would be
brought t<» light."

Ilnga Royal Dublin Society, 1878; .-'■■■ also, Quart. Jour. Qeol. Soc, vol, p 566

Special Localities of Fossil Plan

rs.

The plants referred to in Professor Penhallo.w's paper are derived in part
from deposits belonging to each of the columns in the above table.

(1.) At Green's creek, on the Ottawa river, the Leda clay, there contain-
ing marine shells (Leda aretica, etc.) and bones of Capelin in nodules in the
clay, has in its lower part nodules with leaves, seeds, and fragments of wood.
These have been collected by the late Mr. Billings, Dr. R. Bell, the late
Sheriff Dickson, of Kingston, the late Mr. J. G. Miller, and the writer, and
were noticed in a paper by the writer on the " Evidence of fossil plants as to
the climate of the Post-Pliocene in Cauada," published in the Canadian
Naturalist in 1866. These constitute a considerable part of the specimens
described below. A few specimens of wood have also been found and noticed
by the writer in the Leda clay of Montreal, and the available collections
have been augmented since 1866 by additional specimens from Green's creek
acquired by the Peter Redpath Museum of McGill University.

(2.) The interesting deposits at Scarboro' heights and elsewhere on Lake
Ontario were described by Dr. J. G. Hinde in the Canadian Journal in
1877, and he notices the following plants as found by him :

Wood of pine and cedar.

Portions of leaves of rushes, etc.

Seeds of various plants.

Hypnum commutatum.

H. revolvens.

Fontinalis.

Brywn.

Chara, sp.

More recently Mr. J. Townsend, of Toronto, was -so fortunate as to find
leaves and fragments of wood with shells of Melanin and Cyclas, in beds
apparently of the same age, in excavations in progress on the River Don, at
Toronto. These collections have been acquired for the Peter Redpath
Museum. The section observed at this place is given as follows by Mr.
Townsend :

The locality of the principal vegetable specimens was 150 feet from the
bank of the Don, and in a cutting 70 feet deep. The section showed 26 feet
of fine light-colored sand with layers of clay at bottom. Below this were 24
feet of tough stratified blue clay, the " Erie clay" of the region. At the
base of this clay is a seam of reddish ferruginous sand about three feet thick,
and with argillaceous nodules in which was the maple leaf described by
Professor Penhallow. Below this sand were sixteen feet of alternating sand
and dark-colored clay, with fresh-water shells and wood. Below this was
the blue till resting on the surface of the Hudson river beds. In this section

(315)

.'IK) DAWSON A.ND PENH A I.I.( >\V — PLEISTOCENE FLORA.

the upper bowlder clay of Hinde's section is not represented, but only the

oups III and IV as given in the table. The upper bowlder clay is, how-
ever, seen on higher ground in the vicinity.

Dr. .1. W. Sdencer, who has studied this locality, as well as the whole
north shore of Lake Ontario, writes to me that he regards the earthy sand
holding wood and fresh-water shells as equivalent to Hinde's " interglacial "
beds at Scarboro' heights, and the overlying clay as the so-called " Erie
clay," over which, as above stated, is the upper bowlder deposit which in the
vicinity of Toronto has many Laurentian bowlders.

(3.i Many observations have been made on the interglacial beds by Dr.
G. M. Dawson, and are recorded with sections in his reports on the 4!lth
Parallel and on the geology of the Bow and Belly rivers, and in a paper on
borings made in Manitoba and the North West Territories in Vol. IV of
the Transactions of the Royal Society of Canada ; and he has placed in our
hands specimens of peat and wood from those regions. In one locality on
the Belly river he finds a bed of interglacial peat hardened by pressure in
such a manner as to assume the appearance of a lignite.

(4.) In addition to the vegetable remains found as above stated in the
■• fores! beds " or " interglacial " deposits, trunks of trees and vegetable frag-
ments occur in the bowlder clays themselves, indicating either the partial
destruction of the older interglacial bed and the mixture of its debris with
glacial deposits, or the enclosure of drift-wood in the latter in the manner
now so common in the arctic regions and described by so many arctic ex-
plorers/- This raises very interesting questions respecting the origin of the
bowlder clay, to be noticed in the sequel.

< )ne of the most marked illustrations is that of the boring at Solsgirth, in
Manitoba, on the Manitoba and Northwestern railway, and at an elevation
■ if 1,757 feet above the sea.f At this place the section i< a- follows :

Feet.

1 . Loam 2

l'. Hard blue clay and gravel ._ 42

:;. Hard blue clay and b tones _. h>

1. Hard yellow '.' hard pan'' L2

.".. Softer bluish clay 16

6. " " 71

7. Sand with water __

Blue clay with Btonea 186

'.». Gray clay or Bhale (Cretaceous ?)

860
Fragments of wood, more or less decayed and compressed, were obtained
from depths of 96, 107, 120, and 135 feet from the surface. They were thus
distributed through a considerable thickness of the clay rather than in a

i .if in.- Natural History, Geology, and Physics of Greenland, by Profi — rT. R. Jo

i by tin- I; ">n i Society "f London, i -r . indi ■ " I <■■ Iftw I."

(•Dr. G M. Dawson, Trans. Roys i iada, vol. IV, 1 IV, p. 91,etseq,

REPRESENTATIVE PLEISTOCENE KAUN7E. 317

distinct interglacial deposit. It is to be observed, however, they were
included within the central part characterized as a softer blue clay, between
two beds apparently harder and more stony.

Additional specimens from this place have recently been obtained by Mr.
J. B. Tyrrell, of the Geological Survey of Canada, and have been kindly
communicated to us. Mr. Tyrrell has also found vegetable remains in a bed
under the bowlder clay at Rolling river, Manitoba, which are noticed in
Professor Penhallow's paper. They were accompanied with fresh-water
shells of the following species, determined by Mr. Whiteaves, F. G. S.,
Paleontologist to the Geological Survey of Canada:

Lymnea cdtascopium f, variety with very short spire.

Valvata tricarinata, and a keelless variety.

Amnicola porata f

Planorbis parvus f

P. bicarmatus.

Pis idh im ab clitum.

Sphcerium striatinum.

With these was the centrum of a vertebra of a small fish.

(5.) The most western locality of bowlder clay with plants is that described
by Dr. G. M. Dawson in the vicinity of Skidegate, Queen Charlotte's islands.
At this place hard bowlder clay is overlain by stratified sand and gravel,
ten to fifteen feet in thickness. The bowlder clay in places shows bedding
and holds a few marine shells (Leda fossa, etc.). In tracing the bed along
the coast the shells disappear and the clay is found to contain fragments of
decayed and partially lignitized wood. Specimens of this were collected, but
appear to have been mislaid and could not be found in time for this paper.*

(6.) The most eastern locality from which I have collected Pleistocene
plant remains is that on the northwest arm of the River Inhabitants in Cape
Breton, described in "Acadian Geology," p. 63. This is a hardened peaty
bed resting on a gray clay and overlain by twenty feet of till or bowlder
clay, apparently the lower bowlder clay. It is quite hard and burns with
flame in the manner of a lignite, and contains twigs and branches of
coniferous trees and a great variety of fibrous and epidermal tissues appar-
ently of swamp vegetation, which have been examined'by Professor Pen-
hallow. This locality is of special interest as showing a bed of vegetables
evidently not drifted and under the till or bowlder clay. It shows that iln-
was deposited on what had been a land surface and under circumstances
which did not disturb a bed of soft vegetable matter. It indicates also a
mild climate preceding the deposit of the bowlder clay rather than an inter-
glacial period. There was no evidence in this case of any land-slip or other
accidental disturbance, but rather of successive deposition-.

* Report Geol. Survey of Canada, 1878-'9, p. 91b.

Geographical and Climatal Conditions.

With reference to these I shall first refer to the district from the Atlantic
to the head of Lake ( Ontario.

In this district and the eastern part of North America generally, it is, I
think, universally admitted that the later Pliocene period was one of conti-
nental elevation, and probably of temperate climate. The evidence of this
ia too well known to require re-statement here. It is also evident, from the
raised beaches holding marine shells, extending to elevations of 600 feet,
and from bowlder drift reaching to a far greater height, that extensive Bub-
mergence occurred in the middle and later Pleistocene. This was the age of
the marine Leda clays and Snxirum sands found at heights of 600 feet above
the sea in the St. Lawrence valley nearly as far west as Lake Ontario.

It is reasonable to conclude that the till or bowlder clay under the Leda
clay belongs to the intervening period of probably gradual subsidence, ac-
companied with a severe climate and with snow and glaciers on all the higher
grounds, Bending glaciated stones into the sea. This deduction agrees with
the marine shells, bryozoa, and cirripedes found in the bowlder deposits on
the lower St. Lawrence, with the unoxidized character of the mass, which
proves Bubaquatic deposition, with the fact that it contains soft bowlders,
which would have crumbled if exposed to the air, with its limitation to the
lower levels and absence on the hill-sides, and with the prevalent direction
ofstriation and bowlder drift from the northea-l

All these indications coincide with the conditions of the modern bowlder
drift on the lower St. Lawrence and in the arctic regions, where the great
belt- and ridges of bowlders accumulated by the coast ice would, if the coast
were sinking, climb upward and be tilled in with mud, forming a continue
sheet of bowlder deposit similar to that which has accumulated and is ac-
cumulating on the shores of Smith's sound and elsewhere in the arctic, and
which, like the older bowlder clay, is known to contain both marine shells
ami drift-wood.'j'

The condition- of tin deposil of till diminished in intensity as the Bubsi-
dence continued. The gathering ground of local glaciers was lessened, the

ice was no longer limited to narrow sounds, hut had a wider scope as well

:,- :i tVe. r drift to the BOUthward, :i 1 1< I the climate seems to have been im-
proved. The clays deposited had few bowlders and many marine shells,
and to the west and north there were deposits of land plants, and on land
elevated above the water peaty deposits accumulated.

The shells of the Leda clay indicate depths of less than Inn fathoms. The
numerous foraminifera, so far as have 1m en observed, belong to this range,

• ei ii' in Natural lot, op oit. ; also paper by the author on Bowlder

I > r i > < <it Metis, Canadian R< I ■•' 8< ience, Vol. II, i

ee Royal 3 kretic Manual, London, 1876, op. clt.

WIDESPREAD PLEISTOCENE SUBMERGENCE. .°>19

and I have never seen in the Leda clay the assemblage of forarainiferal forms
now dredged from 200 to 300 fathoms in the Gulf of St. Lawrence.

I infer that the subsidence of the Leda clay period and of the interglacial
beds of Ontario belongs to the time of the sea beaches from 450 to 600
feet in height, which are so marked and extensive as to indicate a period of
repose. In this period there were marine conditions in the lower and middle
St. Lawrence and in the Ottawa valley, and swamps and lakes on the upper
Ottawa aud the western end of Lake Ontario ; and it was at this time that the
plants described in this paper occupied the country. It is quite probable,
nay certain, that during this interglacial period re-elevation had set in, since
the upper Leda clay and the Saxicava sand indicate shallowing water, and
during this re-elevation the plant-covered surface would extend to lower
levels.

This, however, must have been followed by a second subsidence, since the
water-worn gravels and loose, far-traveled bowlders of the later drift rose
to heights never reached by the till or the Leda clay, and attained to the
tops of the highest hills of the St. Lawrence valley, 1,200 feet in height, and
elsewhere to still greater elevations. This second bowlder drift must have
been wholly marine, and probably not of long duration. It shows no
evidence of colder climate than that now prevalent, nor of extensive glaciers
on the mountains; and it was followed by a paroxysmal elevation in succes-
sive stages till the land attained even more that its present height, as subsi-
dence is known to have been proceeding in modern times.

The above sequence applies to the districts of Ontario, Quebec, the arctic
coast, aud the maritime provinces, and might be illustrated by a great
accumulation of facts ; but these may be found in papers published in the
Canadian Naturalist and the Canadian Record of Science and in the reports
of the Geological Survey, more especially those by Dr. G. M. Dawson, Mr.
Chalmers, aud the writer.

For the region between the great lakes and the Rocky Mountains and for
the Pacific coast the sequence is similar, but either the interior region has
experienced a greater elevation or the times must have been somewhat
different. In the mountainous regions of the west, also, more especially
in the interior of British Columbia, the evidence of .great local glaciers is
much more pronounced than on our lower mountains of the east*

I am quite aware that the above sequence and the causes assumed are
somewhat different from those held by many geologists with reference to
regions south of Canada, but must hold that they are the only rational con-
clusions which can be propounded with reference to the facts observed from
the parallel of 45° to the Arctic ocean.

*G. M. Dawson, Superficial Geology of British Columbia: Quart. Jour. Geol. Soc, vol. 34, 1878, p.
89, et seq.; ibid, vol. 37, 1881, p. 272, et seq.

XLII— Bull. Geol. Soc. Am., Vol. 1, 1889.

320 DAWSON AND PENHALLOW — PLEISTOCENE FLORA.

( >ne other poinl remains to be illustrated with reference to the local origin
of the vegetable remains. Where these consist of trunks and branches and
are contained in the bowlder-bearing beds, they may, like those found under
similar conditions in the arctic, be drift-wood, derived Prom great distances
and in a condition of partial submergence of the continent. The facility for
such distribution must, in the Pleistocene age, have been greater than it now
is in the arctic where there is, according t<» the testimony of voyagers, not
only a great quantity of such material on tin- s1k.iv, but mixed with clay and
bowlders at Bome distance inland. There is reason to helieve that through-
out Canada such drift-wood may he found here and there in both the upper
and lower how hhr deposits.

Where, however, we have leaves and other perishable parts, and especially
where there are peat beds and peaty soils, or where the vegetable remains
are associated with fresh-water shells, the case is different. We have in
these circumstances evidence of the local flora, ami cannot doubt that the
climate must have been sufficiently mild to permit the growth iii situ of the
plants whose remains are found. So far as we know at present, evidence of
this kind applies, //;.-/, to the land surfaces anterior to the earlier bowlder
deposit; secondly, to the swamps and upland.- of the Leda clay and "inter-
glacial " period; and, thirdly, to the early modern time succeeding the upper
bowlder drift. The plants specially referred to in the following notes are,
90 far as known, those of the second of the above period-.

In conclusion, it is deserving of notice that the plants indicated in Pro-
fessor Penhallow's lists are not an arctic assemblage, but rather a part of
the cold temperate Mora. They scarcely indicate BO much refrigeration as

that evidenced by the plants from British interglacial beds a- described by
Carruthers.* Further, as the species referred t<> are either local or drifted
by Btreams from the north, it follow- that the arctic flora must have existed

to the north of the Canadian localities referred to. This accords with the

fact proved by arctic explorers and the officers of the Geological Survey of
< !anada,1 that in the glacial period striation and driftage of bowlders point to

drift toward the arctic hasin as well as toward the south. Thus, when these
plant- flourished in Canada, there must have been open water and a land
flora in the arctic basin —condition-, of course, altogether incompatible with

the existence of a polar ice-cap, though not inconsistent with th icurrence

of glaciers in the more elevated districts or those « led by the cold arctic

currents. That the climate was colder, locally at least, in the period of the
bowlder clay need not he doubted, but there i- reason to believe that the
general different f temperature in the BO-called interglacial period as com-
pared with that of the how Ider clay ha- been greatly exaggerated.

on Report, U - . p| i, "Geological Hlatory ol PI i

leology ol Northern Pai ida, Report Geological Survey of Canada, 1887,

II. NOTES ON THE PLEISTOCENE PLANTS. BY D. P.

PEN HALLOW.

The Pleistoceue plants submitted to the author by Sir William Dawson
and described in this paper, are chiefly from collections made by Dr. G. M.
Dawson and Mr. J. B. Tyrrell, of the Geological Survey of Canada, and by
Mr. J. Townsend, with specimens from different localities in the collections
of Sir William Dawson, now in the Peter Redpath Museum of McGill Uni-
versity. A few are donations from Messrs. Worthen and Andrews from
localities in the United States. These latter will be but briefly referred to,
as the precise formation in which they occurred is not wholly free from
doubt. Some of the material is of recent collection and until now unde-
scribed. Other specimens were collected at least twenty years ago, and
have already been more or less fully described* by Sir William Dawson.
These I have submitted to examination for the purpose of verification, and
now present in the following statement.

Annotated List of Canadian Plants.
taxus baccata, l.

The material representing this species was embraced in several slides,
which I have designated by the numbers 1, 2, and 3, and by specimens of
wood, which have also been numbered as follows :

No. 1. A section taken from a specimen from the Don river, Toronto.
The structure is fairly well preserved, and shows the characteristic structure
of Taxus.

No. 2. A longitudinal section of a specimen from Solsgirth, Manitoba,
taken from the bowlder clay of a well at a depth of 135 feet.f The struc-
ture is well preserved, and the taxine characters of the wood are more clearly
recognizable than in the preceding.

No. 3. Transverse section of a specimen also from Solsgirth, Manitoba.
The section is cut diagonally, but as the structure is well preserved the char-
acters are recognizable.

No. 4. A fragment of wood about one and one-half inches square, much
compressed, and evidently the nodal portion of a small stem or branch. It
was collected in 1887 by Mr. Tyrrell from the till formation of the Sols-
girth well. It is readily softened in hot potash, but the whole structure is
badly decayed and much distorted by compression. It everywhere shows
coniferous markings, and where more fully preserved the structure of Taxus
is plainly seen.

c-.in. Nat., Vol. II. 1857. p. 522; ibid., New Ser., Vol. Ill, L870, p. 69; ibid., Vol. VI, 1871, p. K>3.
t Trans. Roy. Soc. Can., Vol. IV, I't. IV, 1886, p. 92.

(321)

322 DAWSON AND PENHALLOW — PLEISTOCENE B'LORA.

No. 5. A specimen from the same locality by the same collector as above.
It represents the broken end of a branch or small trunk about two inches in
diameter. The form has suffered little change, and to the surface there still
adhere small pieces of bark. The preservation of this specimen is so distinct
from that of the others as to lead to the supposition, upon external exami-
nation, that it is a distinct kind of wood. It shows everywhere the effects of
advanced decay, and it is also impregnated to some extent with silica. This
condition uf preservation rendered it extremely difficult to obtain longitu-
dinal sections and impossible to get transverse sections. The former, which
were secured in small fragments, were sufficient to place the coniferous char-
acter of the wood beyond dispute, and in places the spiral structure of Taxus
was evident.

In a recent communication, Mr. Tyrrell stated that specimen No. 4 was
obtained from a depth of 360 feet, and that No. 5 was exceedingly soft when
found ; but the precise depth at which it occurred is not known, though prob-
ably one of those depths at which wood occurred as mentioned in the report
of Dr. G. M. Dawson*

No. (». Embraces two small fragments of wood about one-half inch square
and strongly compressed; also three slides of the same. This material was
collected by Mr. J. B. Tyrrell, in 18<S7, from the drift of Rolling river, two
miles above Heart hill, Manitoba.

Fresh sections were cut, but the material was in such an advanced state
of decay that the treatment with potash had to be applied cautiously, and
microscopical examination showed that it had also resulted in the removal
of a large part of the structure of the cell walls, of which, in most cases, only
the primary cell wall remained. The characteristic markings of coniferous
wood were thus in many cases wholly removed, but in places, where the action
of decay was more limited, the markings peculiar to Taxus were observed.

7. Another specimen of Taxus from peat below bowlder clay on the River
Inhabitants, Cape Breton, obtained by sir William 1 )awson, am! now in the
collection of the Peter Red path Museum, has Keen examined. It is a frag-
ment of a branch about three-fourths of an inch in diameter and >i\ inches
long, much flattened by pressure. The structure shows it to be a Taxus, bul
presenting some aspects different from those of our modern species. These

may have resulted from local conditions, since the w 1 rings show it to

hav<- grown very slowly, as if in a situation unfavorable to it. A more
critical examination will be made later; for the present I refer it to T. /""■-
cata provisionally.

'fhe modem Canadian species of Taxut are T. brevifolia, Nutt., and '/'. boo-
cata, L., var. < 'anad( n is, Gray. To the first, none of the specimens described

♦ ii. i.i.

TAXUS, ASIMINA AND ULMUS. 323

can be referred, as they differ from it in a somewhat marked manner ; but
they do approach the latter species, to which I shall therefore refer them.
Taxus baccata is now found extending from Newfoundland, Anticosti, and
Nova Scotia, Avhere it is abundant, through New Brunswick, Quebec, and
Ontario. On the shore of Lake Huron it often forms impenetrable thickets.
Passing to the west it still continues abundant north of Lake Superior, and
at least to Lake Winnipeg, accordiug to Macoun.*

ASIMINA TRILOBA, DUNAL.

The specimen of this fossil is from the Pleistocene of the Don river, Toronto,
having been collected in 1887, by Mr. J. Townsend, from a cut at Jail hill,
at a depth of sixty-six feet below the surface, and from below the Erie clay of
that locality. It is about six inches long by two wide, and evidently was
derived from a tree of small diameter, as indicated by the curvature of the
growth rings. In its general aspect it bears a very strong resemblance to
the wood of our modern Asimina triloba, with which it is also closely com-
parable in its minute structure. It presents certain differences in detail —
e. g., the development of the thyloses is much more strongly marked, the
wood cells are of smaller diameter, and there are also certain differences in
the markings of the vessels. Alteration under the conditions established
by its long burial may account for some of these, and perhaps none of them
are sufficient to mark a distinct species. I would therefore assign it for the
present to our modern species of A. triloba.

The material was well preserved, and all the details of structure could
be distinguished without difficulty. By boiling in potash, sections were as
readily cut as if taken from fresh material.

At present Asimina triloba, the only species found within Canadian limits,
occurs in Ontario, at Queenstown heights. It is very abundant at Point
Pelee and in the townships bordering on Lake Erie between that point and
Aniherstburg. Doubtless it is not rare along Lake Erie, though not yet
reported (Macoun).

ULMUS RACEMOSA, THOMAS.

This fossil is represented by two specimens, numbered 2 and 3.

No. 2 is twelve by six inches, and evidently derived from a somewhat
huge tree. It was obtained in 1887 from a cutting on the Don river, from
beneath the Erie clay, at a depth of sixty-six feet from the surface, and
associated with the previously described species.

The material is fairly well preserved, though showing the effects of decay
in the exfoliation of the growth layers; while under the microscope the dis-

* The occurrence of Taxus baccata in the Pleistocene deposits of Manitoba has been noticed by
Dr. G.- M. Dawson in the Transactions of the Royal Society of Canada, vol. I V, part I V, 1886, p. :i-'.

\ ,v KHALLOV S N

hich has turned .-ill xhc

civ. This i compn ss the vessels

suited in ilu' . - s dis

trihutcd in th« nond-shap* - - St very mfe
the In:. >vi [n eons*

.! inilx radial or tangt ■mi.-. - - \"\w
wiily to the action of ootas

\ s same K he preceding, *>iU

It a]
.1 small irri - shoe's i . - -

. - four inches lot d one-

Portions boiled in caustic ; tas
- and showed the structure bo be not onl) well . - ed, but

- : compression, so thai the distxibui
ild be readih determined, - the struetu

I, thick-walled cells, shows it to have been a \

Both of \h: - - - sen!

the un - - rueture of tin . - • which I \

- 111 found in i. .
A. clos - >n with these diflferenl sj - - - thai th< ss - -

Imii of referring them botl -

^ thin Canadian limits, / - ather rare in t hi n town-
ling tin - . throughout Ontario, in tin
It s - I to dn r soils, and is us
suj .. su s. It was

an.

roiu the ii

^ - .i !«\ Dr, tvM Da - f ■.; plant

It was eitl
able, th< - : the remnants

s such as

•ii.

\ - in dia

i ilit- /

■ \ - - Sew 1

thin t\»

Moose

THUYA, ELODEA, VALLISNERIA, AND CARKX. 325

limit crosses the Albany at some distance from the sea, extending westward
to a point about seventy-five miles southwest of Trout lake, thence south-
ward to Lake Winnipeg and the United States boundary. It is one of the
trees most likely to be found in this formation. This species has been rec-
ognized by Sir William Dawson in the drift of the Roseau river, Manitoba,
and of Montreal (Leda clay) and the Ottawa river.*

ELODEA CANADENSIS (?), MICHX.

A specimen of soft stone bearing the impress of a small branching plant
and the carbonized remains of another of the same kind. This was from
the collection of Mr. Tyrrell, made in 1887, and obtained from Rolling
river, Manitoba, two miles above Heart hill. A slide of the same plant and
from the same locality, from Dr. G. M. Dawson, shows the plant to have
been herbaceous, but with a distinctly vascular axis, the wood cells of which
are thin walled and with rather blunt terminations. This vascular structure
is surrounded on all sides by a distinctly parenchymatous structure. Asso-
ciated with this plant are many diatomaceous remains belonging to fresh-
water species, among which I have recognized Navicida lata, N. legumen,
Encyonema prostratum, Denticida latda, and various species of Licmophora (?)
and Cocconeis. It is therefore clear that the plant is not a seaweed. The
distinctly branching habit and the structure suggest Elodea, although the
state of preservation is not such as to render exact comparison possible. I
therefore refer it provisionally to our common Canadian species, E. cana-
densis, which is everywhere found in fresh water.

VALLISNERIA (?).

Several fragments of the same earthy material as above, bearing each a
small fragment of a leaf. This is in each case linear, with a well-rounded
apex, and usually about 2.5 mm. wide. The epidermis is apparent under a
pocket lens. In fact the remains appear to consist wholly of the two epi-
dermal layers, which may be separated readily. Under the microscope the
epidermal cells are found to be well preserved. No stomata have been found,
and this, together with the presence of fresh-water diatoms, would indicate
that it must have been a submerged, aquatic plant. The structure strongly
reminds one of Vallisneria, to which I shall provisionally refer it. This
plant is everywhere common in fresh water, and is very likely to have
occurred in such a locality as that from which the fossil was obtained.

CAREX MAGELLANK'A, LAMARCK.

The Green's creek nodules contain an abundance of leaves, evidently of
grasses and sedges. In one nodule from the Miller collection and in two

* Can. Nat., New Ser., Vol. Ill, 1808, p. Tl\ Report on 19th Parallel, 1875, p. l\\ ; Notes on IVst-I'lio-
cene, op. cit., 1871, p. 40L

32G DAWSON AND PENHALLOW — PLEISTOCENE FLORA.

belonging to the collection of Mr. John Stewart, of Ottawa, there were
found portions of old spikes devoid of seeds, lmt with the persistent glumes
widely Bpread, evidently the remains of a Carex. In other nodules belone-
ing to the Miller collection in the Peter Redpath Museum, there were found
complete Bpikes containing the seeds, apparently the same as the preceding.
In both cases the resemblance to Carex magellanica is so marked that I have
ventured to refer them to it.

At present this species is found in peat bogs from Newfoundland to
Vancouver.

BRASENIA PELTATA, PURSH.

This is evidently an undeveloped leaf, of which only one-half, embracing
the stump of the petiole, is represented. The form and, to Bome extent, the
venation -how its probable relation to the species above named.

Brasenia peltata occurs at Rocky lake. Nova Scotia; Grand lake, Mew
Brunswick; Point St. Charles, Montreal; River Range; and is abundant
throughout the northern counties of Ontario, and about Rainy lake and
Lake of the Woods, according to Macoun.

LARIX AMERICANA, MICHX.

Several small branches about three inches or less in length and from one-
third to three-fourths of an inch in diameter, from the < reological Survey of
Canada, through Sir William Dawson. They were collected by Mr. J. < '.

Weston from the Leda clays in Peel's clay pit, Montreal.- The structure 18

fairly well preserved and recognisable without difficulty.

In its present distribution, Larix americana is common in all swampy
iund from Newfoundland and Labrador, through the eastern provinces,
to the fool of the Pocky Mountains; northward to latitude (io°.

POPULUS GRAMHI'KNTATA, MICHX.

I',;i-' -I a small stem or branch about two and one-half inches long. The
structure is quite well preserved and readily comparable with the above
species. It was obtained from the f."l>i clays of Montreal by Mr. J. C.
Weston, :nid transmitted to me from the Geological Survey of Canada by
Sir William Dawson. Af-o in Dodules from Green's creek, Ottawa, now in
the collection of Mr. J. Stewart, small branches of this same Bpecies were

found

Populut grandidentata is common in Nova Scotia and New Brunswick, as
also throughout Quebec and Ontario.

A NEW SPECIES OF ACER. 327

POTAMOGETON RUTILANS (?), WOLFGANG.

A single specimen in a Green's creek nodule from the collection of Mr. J.
Stewart. It embraces the stem and several leaves. »

This species is at present known only near Red Rock, Lake Superior, and
on Twin island, James's bay; in marshes on Anticosti ; and at the mouth of
the Nipigon river (Macoun). It would therefore appear probable that it
was more abundant in the past than at present.

EQUISETUM LIMOSUM (?), L.
E. SYLVATICUM (?), L.

Fragments of plants with lateral members in whorls were frequently met
with and, although not satisfactorily referable to any modern genus, pre-
sented the closest resemblance to the two species of Equisetum above named,
to which they are provisionally referred.

MENYANTHE3 TRIFOLIATA, L.

A specimen of the Leda clays from Montreal, now in the Peter Red path
Museum, shows the remains of a plant of which only the basal portion is
preserved. This consists of a central axis from which rather stout lateral
members are developed at right angles, and from which in turn are pro-
duced numerous fine roots. The specimens are of small diameter, but from
their evidently shrunken character must represent the remains of plants ap-
proaching one-quarter of an inch in diameter. Although not clearly refer-
able to any existing species, the resemblance to the stem of Menyanthes
trifoliata is very striking, and in all probability it represents a similar under-
ground stem with its roots developed at right angles to the axis of growth.
The absence of leaves renders a more accurate determination at present
impossible.

Description of New Species.

acer pleistocenicum, sp. nov.

This fossil was recently obtained by Mr. Townsend from the Pleistoeene
of the Don river, Toronto, and was purchased by Sir Willam Dawson with
other specimens and presented to the Peter Redpath Museum. Though nol
perfect as to form, the leaf is beautifully cast in an argillaceous nodule, and
shows several details of venation quite perfectly. A drawing, giving a
restoration of the leaf, is herewith presented. From this ii will be aeen thai
the left half of the blade is nearly intact, while of the right half only about
two-thirds remain, the lobes being entirely cut off by fracture of the matrix.

The leaf is evidently that of a maple, although of a type quite distinct
from any of our existing forms. As will appear from the figure, the general

XLIII— Bull. Geol. Soc. A.m., Vol. 1, 188!).

328

DAWSON ANh I'EXIIAI.I.oW — PLEISTOCENE FLORA.

form and venation suggest Platanus, and a specific name indicating this
k semblance would be appropriate, were not some of the existing species al-
ready bo distinguished. It is to be regretted thai this is the only specimen
so far found in a fairly complete condition, since it is unsatisfactory to base
conclusions upon a single specimen where there i> opportunity for variation.
The modern maples with which the fossil is most nearly comparable arc
Acer rubrum and .4. ji/afnnoides. In its general outline, the fossil is broadly

, — r-
- /

I i..i u L— At urn.

ovate and, if W6 follow 1 1 1 < - same ride as in other maple leaves ID re-peel to

the number of lobes being determined by the palmate distribution of the
principal veins, three lobed ; bul the terminal lobe has two prominenl lateral
lobes, while the others have each a .-mall basal lube, all Bomewhal Btrongly
defined and making the leaf appear seven lobed. The lobes are all very

RELATIONS OF ACER PLEISTOCENICUM. 329

acute. The margin is entire with the exception of two teeth, one on each
side and situated midway between each lateral lobe and its inferior lobe.
The sinuses are open, shallow, and well rounded. In many of these respects
it approaches Acer platanoides, from which it differs in its much broader
terminal lobe and in the broader and more shallow sinuses.

The venation is most nearly comparable with that of Acer rubrum, where,
as in the fossil, only two veins are arranged palmately with the midrib, and
from these branch smaller veins which run to the small basal lobes.

The second and third veins, lateral to the midrib, run to the principal
sinus of each side, where they terminate near the margin by repeated diehot-
omous branching. This, however, is common to several of the modern
maples. The finer venation is essentially the same as in our modern maples.

It would appear from this that the fossil cannot be properly referred to
any of our existing species, and it appears desirable to give it a distinctive
name. I therefore propose to call it Acer pleistocenicum, as properly de-
scriptive.

Revision op previously recorded Pleistocene Plants.

The following specimens from Green's creek, as referred to by Sir William
Dawson in the preceding pages, have already been partially determined by
him and published in 1868, with figures of some of the species.* The pres-
ent revision shows a few changes and includes a few specimens not originally
noted, and which have been acquired by the Redpath Museum from the
collection of the late Mr. J. G. Miller since the publication of Sir William
Dawson's paper:

DROSERA ROTUNDIFOLIA, L.

A nodule containing a single specimen of what appears to be a leaf of
this plant, showing marginal projections and surface markings bearing some-
what close resemblance to the glandular hairs. Its association with the
fertile spike of an Equisetum shows it to have been a habitant of moist places
such as are usually favorable to its abundant development. It is a species
very commonly distributed throughout Canada.

ACER SACCHARINUM, WANG.

A basal fragment of a leaf in a nodule. This specimen was originally
designated f as A. montanum, Ait. (A. spicatum, Larnx). The only data on
which a determination is possible are to be found in the angles at which the
veins separate and in the number and distribution of such veins. With
reference to the first, it is to be observed that the angles of the veins with

*Can. Nat, New Ser, Vol. Ill, p. 70 et seq.
t Ibid.

330 DAWSON \M» PENHALLOW — PLEISTOCENE PLORA.

the midrib vary considerahly in the same species, so that this cannot be re-
garded as a character of more than approximate value. The number and
distribution of the veine offers a somewhat more reliable guide, aince there
is a constancy in this respect which is of value. The majority of our maples
tall in one of two types. In the first case, four principal vein- are arranged
palmately with the midrib, and directly extend to as many distinct lobes of
the leaf, the first pair usually extending horizontally or obliquely downward
to the basal lobes. To this type can he referred such species as Acer ptata-
unit!,.* and .1. siici-hnriiniin. In the second case, only two principal vein- are
directly and palmately arranged with the midrib, while from each of them
there Bprings a subordinate vein at a short distance from the base, which
then extends to the corresponding basal lobe. Examples of this type are
to he mi n in Acer rubrum and A. dasycarpum, as well as in the fossil A.
pleetoa ni nun.

In the fossil under consideration there are four distinct veins palmately
arranged with the midrib, two of which are large, and the other two run-
ning to the basal lobes. It will thus he seen that comparison with Acer
montanum cannot he considered. A close comparison with the leaves of the
first group shows that it approaches most nearly to Acer saccharinum in all
those characters represented.

The present distribution of A. saccharinum covers a wide range through-
out Canada, from Newfoundland and Nova Scotia to the western extremity
of Lake Superior, and northward to Lake St. John and to the Long portage
on the Michipicoten river.

POTENTILLA ANSKKINA, I..

Two specimens and their reverses in nodules previously determined as
Potentilla canadensis and /'. norvegica, and also a specimen ami it- re-
verse in Mr. Miller's collection in the Peter Redpath Museum. The leaves
only are represented, hut the venation is so distinctly preserved, as well as
the general form and margin, as to leave little doubt as to their true char-
acter, although iii one case tiny are ao grouped by crushing as to hear a cer-
tain resemblance to the leaf of P. canadensis. In this Bpecies the veins run

directly from the midrib of the leaflet to both teeth and sinuse8. In /'. imr-
vegica the veins run to the teeth, taking a direction which tends to become
parallel with the margin, and while the vein it-elf extends into a tooth it

off a lateral which penetrates the t"<>th below, SO that there are in

r< ality twice a- many teeth a- veins. The fossils, which in this respect as in

other- :ire :d| -imihir. .-how the vein.- running directly to every tooth, veins

and teeth being equal in number.

In this respect, a- well as in the form of the leaflet, the shape and apices

• i , Vol. III. 1868, p. 7".

PLANTS PREVIOUSLY DESCRIBED. '.I'M

of the teeth and their inclination to the midrib, the fossil corresponds most
closely with P. anserina, to which I therefore refer them. At present this
species is very abundant along the eastern coast and on the margins of rivers
and lakes throughout the interior and as far north as the Arctic sea.

GAYLUSSACIA RESINOSA, TORR. AND GRAY.

A well-preserved leaf in a nodule. This shows the form of the leaf, and
the resinous dots are so perfectly seen as to render it readily determinable.
This species is now found in rocky or sandy woodlands and in bogs, from
Newfoundland and Nova Scotia to the Saskatchewan.

POPULUS BALSAMIFERA, L.

The material representing this species is embraced in leaves and fragments
of branches contained in nodules. The former are in most cases well pre-
served and admit of easy identification. As noted in the original descrip-
tion, however, the leaves are all small, and assuming them to be mature this
would indicate a cold climate or very exposed situations. At present P.
balsamifera is of very wide distribution throughout Canada, extending north-
ward to the mouth of the Mackenzie river, where it attains large size, and is
an important source of fuel (Macoun).

POTAMOGETON PERFOLIATUS, L.

Portions of leaves and seeds in nodules. The venation is beautifully dis-
tinct, and it is without much doubt referable to the species named. This is
one of our most common water weeds, being found everywhere in the streams
of the northern United States and Canada.

POTAMOGETON PUSILLUS, L.

This is one of the most abundant plants contained in the uodules from
Green's creek. The specimens all show a branching plant with narrow
leaves. This species is now common in slow streams and ditches almost
everywhere.

ilnUISETUM SCIRPOIDES, MICHX.

Common in the nodules from Green's creek, and associated with Potentilla
anserina. This is a widely distributed species, and would naturally occur
among such plants as are found at the above locality.

There is also another nodule containing a portion of a stem cut longitu-
dinally. It has the appearance of an Equin turn, ami may possibly be re-
ferred to one of the larger species, such as E. palmtre or El litnomm.

ORYZOPSIS A9PERIFOLIA, MICHX.

A fragment of a leaf and stem in a nodule, showing features which make
them correspond closely with Oryzopm asperifolia, and to which I therefore

332 DAWSON AM> PENHALLOW — PLEISTOCENE FLORA.

refer them. This species is a widely extended one, being found from New-
foundland to the Rocky Mountains.

IT'

A specimen of a Beaweed in a nodule, evidently a Fucus. It is not strictly
comparable with any of our modern Bpecies, :in<l until more material is ob-
tained it serins besl not to assign any specific name to it, although digitatus
would appear to be appropriate.

FONTINALIS.

Fragments of mosses are common in the nodules from Green's creek.
These appear to be chiefly of the genus Fontinalis, or one nearly related
to it.

Jn addition to the above there were also found in the Green's creek nodules
various seeds. These require some further examination.

BROMUS CILIATUS, L.

A fragment of a leaf which shows a venation closely corresponding to
Bromus ciliatus, to which I would for the present refer it. This is a very
common Bpecies in thickets and damp places throughout Canada. The
specimen was collected by Mr. J. G. Miller from Green's creek.

GEN. AND SP. UND.

Among the specimen- sent us by Dr. G. M. Dawson was a seed collected
by Mr. J. B. Tyrrell, in 1887, from the Rolling river, Manitoba, two miles
above Ibart hill. The form and size seem to indicate that it is the seed of
a Conifer.

LlGNIT] -.

\ sample of lignite or indurated peat, collected by Dr. G. M. Dawson
from the interglacial deposits of Belly river, was presented in the form of
balsam mounts and loose material, all of which had been treated with potash,

nitric acid, sulphuric acid, or chromic acid. In all cases the material was

found to be very finely divided, none of the fragments being of sufficient

-!/•■ to make reference to particular orders or genera possible. It was, how-

r, quite possible to recognize fragments of sclerenchyma tissue, fragments

i.| wood cells, Bpores of ferns, and what appeared to he the eztine "I' pollen

H-. These latter, together with the few spores, constituted the bulk of
the recognizable material. There were also to be observed fragments of
epidermis, apparently of three different kinds, and in one instance two
stomata were found, though imperfectly preserved. The impression gained
from a careful examination of a large amount of material is that the

SYNOPSIS OF PLEISTOCENE PLANTS. 333

peat consists of the remains of ferns and herbaceous or semi-woody plants.
No more definite statement can be made until other material is examined.

A specimen of lignite from Cape Breton was also submitted to exami-
nation. This material was described some years since by Sir William
Dawson,* and is also noted in the preceding pages of this paper by him.
Boiled out in potash, there have been found in it an abundance of fungus
hyphse, the extine of coniferous pollen, bast cells, sclerenchyraa tissue of
ferns, epidermis apparently of ferns, wood cells showing a portion of a
medullary ray, and fragments of endogenous stems. This is all that could
be found after searching through a large amount of material, and the con-
clusion was reached that the lignite represents the remains of ferns and
grasses with fragments of woody plants, possibly from a more elevated and
less wet locality.

Woods from Illinois.

In addition to the specimens above described, I have also examined three
slides of coniferous wood from Bloomington, Illinois. f These were found at
depths of 100 and 107 feet from the surface, and were said to be at the bottom
of the bowlder clay. They were provisionally designated as Abies, but a
careful comparison with existing species of Abies, Tsuga, and Picea has led
me to refer them to Picea alba, Link.

There were also two slides of Taxus baccata from the same locality, at a
depth of 107 feet.

Synopsis.

The following summary of species and their distribution may be given :

1. Asimina triloba, Dunal. Don river, Toronto (Townsend).

2. Brasema peltata, Pursh. Green's creek nodules (Miller).

3. Drosera rotundifolia, L. Green's creek, Ottawa (J. W. Dawson).

4. Acer sacchariuum, Wang. Green's creek, Ottawa (J. W. Dawson).;};

5. Acer pleistocenicum, sp. nov. Don river, Toronto (Townsend).

6. Potentilla anserina, L.

Green's creek, Ottawa (J. W. Dawson and Miller).

7. Gaylussacia resinosa, Torr. and Gray.

Green's creek, Ottawa (J. W. Dawson).

8. Menyanthes trifoliata, L. Leda clays, Montreal. J

9. Ulmns racemosa, Thomas. Don river, Toronto (Townsend).

10. Populus balsamifera, L. Green's creek, Ottawa (J. W. Dawson). |

* Acadian Geology, 1878, p. 63.

t Presented to .Sir William Dawson by Dr. Andrews and Professor Worlhen, and now in the
Peter Kedpath Museum.

{Collection of Sir William Dawson in Peter Redpath Museum.

. (.1

:'»| DAWSON ANI> PENHALLOW — PLEISTOCENE FLORA.

11. Populue grandidentata, Michx.

1. ill claj b, Montreal I Weston ■
( rreen'a creek nodules Stewarl i.

12. Picea alba, Link. Bloomington, 111. (Andrews

L3. Larix americana, Michx. Leda clays, Montreal (Weston).
1 I. Thuya occidentalis, L.

Leda clays, Montreal (Sir William Dawson).

Leda river. Manitoba (Dr. G. M. Dawson).

.Marietta, Ohio (Newberry).
I"). Taxus baccata, L.

Don river, Toronto (Townsend).

Solsgirth, Manitoba < G. M. Dawson and Tyrrell).

Rolling river, Manitoba (Tyrrell).

(ape Brel Sir William Dawson).

Bloomington, 111. (Andrews).

16. Potamogeton perfoliatus, Ij. Green's creek, Ottawa (J. W.Dawson).

17. Potamogeton pusillus, L. Green's creek, Ottawa (J. W. Dawson |.

18. Potamogeton rutilans (?), Wolfgang. Green's creek nodule (Stewart).

19. Elodea canadensis (?), Michx. Rolling river, Manitoba (Tyrrell).

20. Vattisneria (?). Rolling river, Manitoba (Tyrrell).

21. Carex magellanica, Lamarck.

< ireen's creek nodules, Ottawa (Miller and Stewart).

22. Oryzopsis asperifolia, Michx. Green's creek, Ottawa (J. W. Dawson).
!■'>. Bromus eiliatus (?), L. Green'.- .reek, < Ottawa (Miller i.

24. Equisetum sylvatieum (?), L. Green's creek nodules (Stewarl I.

1~>. Equioetum limosum (?), Ij. Green's creek nodules (Stewarl i.

26. Equisetum tcirpoide*, Michx. Green's creek, Ottawa (J.W. Dawson).

27. Fontinalis (?), sp. Green's creek, Ottawa (J. W. Dawson).

28. / ■'"' " . s|>. Green's creek, Ottawa (J. W. Dawson).
I'.K Navicula lata. Rolling river, Manitoba.

.'!<). Encyonema prostration. Rolling river, Manitoba.

31. Denticula lauta. Rolling river, Manitoba.

'.)!. Liemophora (?). Rolling river, .Manitoba.

33. Cocconeis. Rolling river, Manitoba.

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA

VOL. 1, PP. 335-356

THE VALUE OF THE TERM "HUDSON RIVER GROUP" IN

GEOLOGIC NOMENCLATURE

CHARLES D. WALCOTT

WASHINGTON

PUBLISHED BY THE SOCIETY

April, 1890

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA
Vol. 1, pp. 335-356 April 14, 1890

THE VALUE OF THE TERM "HUDSON RIVER GROUP" IN

GEOLOGIC NOMENCLATURE.

BY CHARLES D. WALCOTT.
(Read before the Society December 27, 1889.)

CONTENTS.

Page.
Introduction 335

Historical and Descriptive Notes 335

Chronologic Arrangement of Names 344

Discoveries of Recent Years 344

Value of the Term 351

Discussion 354

Introduction.

From the windows of the building in which we are assembled we can look
out over the broad expanse of the river * upon which Henry Hudson sailed
two hundred and eighty years ago (1609). It was afterward christened
"Hudson" by the English, and it has retained this name with the unani-
mous consent of the geographers of the centuries since. It seems well to-day
to consider the place of the same name in the geologic nomenclature of
America, as its retention has been threatened by the conclusions of various
geologists, some of whom have, while others have not, studied the rocks of
the Hudson valley.

The question before us is, What is the value of the term "Hudson River,"
in the light of the latest geologic research ?

Historical and Descriptive Notes.

The rocks of the valley of the Hudson were described in a general way
by Amos Eaton, in a series of publications extending from 1817 t<> L832.1

* Discovered by Verrazzani in lr>_'i. Named " River of the Mountains" bv Hudson in L609, and
called " Mauritius" in honor of Prince M auric sau by Englishmen a short time after, about

1692 it became generally known as the North River.

+ Index to the r;eoioKv of the Northern States, (818, 2d ed., i ■■■ I. and Agrlo, Surrey

Rensselaer county, 1822: Geol. Text Book, 1830, 2d ed., I

XLIV-Bir.r.. Geoh.Soo. A.m., Vol. l, 1889.

330 C. D. WALCOTT — TIIK TERM "HUDSON RIVEB GROUP."

In 1820,* Rev. Chester Dewey published an account of a section extending
from the Taconic mountains to the Hudson river at Troy. His observa-
tions and those of Eaton are too general in character to be ol' more than
historical interest at present.

With the advent of the Geological Survey of Xew York, in 1836, system-
atic work was inaugurated and a classification developed which gave a
great impetus to geologic research in America.

The first geologic district embraced the valley of the Hudson, and was
placed in charge of Dr. W. YV. Mather, who, in 1*40, proposed the name
" Hudson River Slate group." He says, in speaking of the rocks in the
valley of the Hudson :

The lowest in the series is the Hudson River Slate group, consisting of slates, shales,
and grits, with intcrstratitied limestones, all of which occur under various modifica-
tions. This group is overlaid unconformably in many places by the various rock
formations of more recent origin. The next in order of superposition in the district
under examination * * * is the Shawangunk grits. * * * The next in order
is the Helderberg group; * * * and the Catskill Mountain group terminates
the series of indurated rocks in the First district. f

From Kingston the Hudson River group ranges along the right or western
bank of the Hudson river to Albany, underlying the superincumbent rocks
unconformably, with few exceptions. A few fossil shells or impressions of
shells were found in the sandy beds, and some graptolites in the black duties
underlying the Shawangunk grits. In the final report of the firsl district,
Dr. Mather changed the name Hudson River Slate group to Hudson River
group.J The group as described may be classed by its structural relations
into two divisions: (1) The approximately horizontal, unaltered strata, w< at
of the line of disturbance in the valley of the Hudson. (2) The strata within
the area of disturbance in the immediate vicinity of the river and to the east
of the valley.§

The described sections of the undisturbed strata are portions ol' the highest
pari of the series, not far beneath the conformably superjacent Helderberg
division. A measured section of 141) feet 4 inches at Schoharie kill, Scho-
harie county, .-hows an alternating series of shales with arenaceous layers or
grit.-, Borne of which are calcareous. The thickness of the group could not
be ascertained in any part of the Hudson ami Champlain valleys, in conse-
quence of the rocks having been deranged, upheaved ami tilted ; but in the
valley- of Norman's kill, the Mohawk river ami Schoharie kill, they are
beautifully exposed to view. No actual measurement of these strata have
been made, loii it is estimated that they have a thickness of from 500 to 800
feet 1 1 The paleontologic evidence of the position of the strata consisted of

• Amer. Jour. BoL, vol. j, 1820, pi

nil, \ on Rep Qi irvey N. Y., i-i", p Ji-'.

'..-., I. V V., '.■■•■I. !■ o-i I I. hi-!., I-I :, p. :'.'.7.

!.-•■. •■it.. |.|.

k Loc. ctt., |.

THE NEW YORK STATE SURVEY. 337

a few fucoids and graptolites and a few specimens of testacea, none of which
were designated by name.

Mr. Larduer Vanuxem accepted the term proposed by Dr. Mather, and
described the Hudson River group as he found it in the Mohawk valley.
It there rests upon the Utica slate throughout the district, and is next in
order as to age. It is followed by the gray sandstone of Oswego, the rock
which immediately succeeds it in the district where that rock exists.*

He further says :

The name is adopted as being generally used in the Survey and as being more com-
prehensive than the one heretofore used ; it is, however, objectionable from the diffi-
culty in defining its limits along the region of the Hudson river.

In Schoharie county the Hudson group is undisturbed and unaltered, and its maxi-
mum thickness is not less than 700 feet, but from the absence of the succeeding rock
its precise position is not made known. Further west, in the same district, the' whole
series is complete and its position well denned. f

Mr. Vanuxem considered this group one of the universal ones, and that
its two divisions are not coextensive : the lower one enters the first dis-
trict along the Mohawk, and extends north by Rome through Lewis into
Jefferson county ; the upper division first appears in Oneida county, and
from thence west and north it is an associate of the Frankfort slate or the
lower division.

The sandstone-shales of Pulaski are fossiliferous portions of the second or
upper division of the Hudson River group. As respects its fossil history, it
will probably be subdivided, from the following facts: Fossils are rare in
the lower part of the Frankfort slate, but are numerous where it joins the
next series, the Pulaski shales. There is no essential difference between the
fossils of this place, whether seen at the mill-race at Lee Centre or Whitall's
quarry near Rome, at Halleck's spring iu Hampton or in the gully near Utica
or on the Cohoes near Waterford. In all these localities the group of shells
which so peculiarly characterize the Pulaski shales is wanting, and others
appear that had no previous existence in the district. J The upper division,
or Pulaski shales, is stated to be characterized by Cyrtolite* ornahis, Am-
bonychia radiata, Modiolopsis modiolaris M. eurva, M. ovata; also Orlhon<<f't
parallella, and other species not yet described.

Rome, New York, is given as the first locality west of the Hudson where
the upper division is found. To the west of Rome, and north through
Lewis county, it covers a large portion of the west side of the range of the
Hudson River group. In Ohio and Indiana the upper division is seen with
its fossils; the lower one has not yet been observed. It is there highly

*Geol. N. Y., Survey Third Geol. Disfc, 1842, pp. 60-C7.
fLoc. cit., pp. 60-61.
I Loc. cit., p. 64.

,.>.

C. D. WALCOTT — THE TERM "HUDSON RIVER GROUP.

calcareous, and forma the upper pari of the blue limestone of these two
states.*

In January, L842, I>r. Emmons described a series of shales in the Hudson
River valley, and spoke of them as the Hudson River Beries or group. He
Baysf that the whole extern of this group north and south is not well ascer-
tained. It is known, however, to appear far northeast of Quebec, from
whence it is traced south through Canada, Vermont and New York, and
thence through Pennsylvania into the southern state-. He does not corre-
late it with the Lorraine series of the northwestern part of New York.

Professor dames Hall, in mentioning the Hudson River group in the
report of the Fourth district, says : X

■■ Where the strata are undisturbed a well marked line of division usually separates
this group from the Utioa slate; but along the Hudson river, and in other places
where disturbance has prevailed, the two are not easily separable."

A list of fossils characteristic of the group is given, nearly all of which
are found in the upper division hut not in the Hudson River valley.

Professor Hall described the fossils of the Hudson River group in the
first volume <>f the Paleontology of New York. L847. The larger propor-
tion of the species illustrated, with the exception of the graptolites and a
\'r\\ Lower-Cambrian fossils from east of the Hudson, were obtained from the
interior of the state of New York, southern Indiana ami Ohio, ami north-
ern Wisconsin. At Waterford,on the Hudson, a few species were collected

that served to connect the fauna of the Frankfort .-hale with that of the
Hudson River shale; of this fauna the single species, Ambonychia r<t<li<tt<t, in-
dicates the fauna of the upper division of Yanuxciii. The graptolites of
tin- black -hale on the west Bide of the Hudson river, as known under the
present nomenclature, include the Id genera ami '_!'.» species listed below, 6
genera ami !» species of which occur in the Utica shale of the Mohawk
valley :

Rastrites barrandi, I [all.
Qraptolithn* (?) In, ,-,'.<, Hall.
Leptograptus subtenuis, Hall.
Amphigraplus divergent, Hall.
Stephanograptus gracilis, Hall.

surcularis, Hall.
DidymograptuB 8erratultis, Hall.

lagittariw, Hall.
( 1rmatograptu8 multifaseiatus, Hall.

I oc. 'it . i

I ! I | :

\ ■> , Survey Fourth 0e< i ■.. p 30.

GRAPTOLITES OF THE HUDSON VALLEY. o.".!)

Dicellograptus divaricatus, Hall.

sextans, Hall.
Dieranograptw ramosus, Hall.
" furcatus, Hall.

ramosus, Hall.
Glimacograptus parvus, Hall.
typicalis, Hall.
scalar is, Hall.
Diplograptus angustifolvus, Hall.
marcidus, Hall.
pristis, Hall.
putillus, Hall.
secalinus, Eaton.
spinulosis, Hall.
tvhitfieldi, Hall.
" mucronatus, Hall.

Retiograptus barrandei, Hall.

geinitzianus, Hal 1 .
Thamnograptus capillaris, Hall.
" typus, Hall.

Of the preceding species, Didymograptus serratulus, Hall ; Dicellograptus
divaricatus, Hall; Dicranograptus ramosus, Hall; Glimacograptus bicomis,
Hall (doubtful); Climacograptus typicalis, Hall; Climacograptus scalaris,
Hall; Diplograptus pristis, Hall; Diplograptus putillus, Hall, and Diplo-
graptus mucronatus, Hall, occur in the Utica shale of the Mohawk valley,
and Diplograptus amplexicaule of the Trenton limestone is found in the upper
portion of the Lorraine section.

In the third volume of the Paleontology of New York, 1859, Professor
Hall describes the Hudson River group, as known to him in the Mississippi
valley and Canada. He says : *

" The group of strata known as the Hudson River group, which in its more ex-
tended signification may include all the beds from the Trenton limestone to tho
Shawangunk conglomerate, has afforded in New York but small additions t'> tin'
number of fossils previously known in this formation."

In 1862 f Professor Hall concluded from the results of the extended study
by the Canadian geologists, especially Sir William Logan, thai the strata
referred to the Hudson River group in the valley of the Hudson belonged
to an older geologic epoch than that referred to the same group in western

*Loc cit., p. 1 1.

fKep. Geol. Survey, Wisconsin, vol. 1, 1862, p. 17 (foot Dote)

340 C. D. WALCOTT — THE I'KKM "HUDSON RIVEB GROUP."

New York and tlie Mississippi valley, He then proposed to drop the term
Hudson River group. In explaining this note he Bays:*

•• In the nomenclature proposed by the geologists of the State of New York for

the Beveral formations within the region of country explored by them the term Hud-

l; ■ • group was applied to a series of shales and argillaceous sandstones, with

intercalated beds of limestone, which exist in great force along the Hudson river

valley for a hundred miles above the Highlands.

••In this disturbed region the order of sequence does not appear to have been fully
made out; but a- the western extension of the Hudson-valley rocks along the Mo-
hawk valley had been (as then supposed) traced to a junction with rocks known in
the Annual Reports of the State Geologists by the names of I ate, Fra

slate, shales and sandstones of Pulaski, and Lorraine shales, which rocks were known
to rest <m the Trenton limestone group, the single term of Hudson River group was
proposed to embrace the entire series. In this the expressed object was to give the
name from the locality which ofl'ered the most complete and extensive exhibition of
the strata composing the group."

He stated that he was satisfied from the geologic relations of the great
mass of these slaty rocks and Prom their contained organic remains that they
were of older date, and that the fossils of newer age occurring in differenl
localities have not been regarded as characterizing the formation ; that the
great mass of the Hudson River rocks in the typical localities arc older than
the Lorraine -hale-, the shales and sandstones of Pulaski, etc. ; and that the
term Hudson River group cannot properly be extended to these rocks, which,
on the wesl Bide of the Hudson river, are separated from the Hudson River
group proper by a fault not yet fully ascertained. He added :

"There can be no propriety in transferring the name Hudson River group from it-

typical locality and applying it to rocks which we now know to 1 f younger age,

and which, when the sequence is complete, are separated from the Hudson River
rocks by a great limestone formation.

■ I have therefore dropped the term Hudson River group in its application to the
rocks of Wisconsin, which are of the age of the Lorraine shales of New Fork and
the Blue limestone group of Ohio.-'

Fifteen years after publishing the note in the ( S-eology of Wisconsin in L862 .
Professor Hall reviewed the evidence on which his conclusions were based
and decided that he had been in error in dropping the term Hudson River
group. He Baysl thai be accepted the determination made by the Geologi-
cal Survey of Canada regarding the extension of the older rocks marked
by the preseuce of a primordial fauna into the Hudson and Champlain val-
leys; also, al the time, the suggestion thai the few fossils of the Trenton
fauna of the Hudson River shales were contained in some outliers of insig-

R ivi t Group in \ne fom-

- i , rol. -'■, 1877, pp.

CONRAD S NAME, "SALMON RIVER.' 341

nificant extent embraced within the folds of the older rocks or restiug upon
the primordial beds of the fundamental rocks of the valley. The graptolites
of the valley of the Hudson were referred to the primordial fauna by Mr
Billings, and the slates of the valley of the Hudson were claimed by Sir
William Logan to belong to the primordial period, and not to the Lower Si-
lurian as supposed by the New York state geologists.

From the data obtained subsequent to 1862, Professor Hall decided that
the graptolites and all other fossils collected belonged to the second fauna —
i. e., from the localities within the valley of the Hudson to which he refers.
He says in conclusion :

" It [the term Hudson River group] has been accepted in geological nomenclature
and it is incorporated in all our publications. We cannot, now, apply the term Cincin-
nati, or any other name to the shales and sandstones which exist in great development
along the Hudson river, extending thence to the Mohawk and its tributaries, and
traced in wide extension and highly fossiliferous character throughout the north-
western counties of New York." *

Dr. Ebenezer Emmons studied the strata between the Trenton limestone
and the Medina sandstone in Jefferson county and the adjoining county
of Oswego, New York, and proposed the name Lorraine for the rocks be-
tween the Utica shale and the Oswego sandstone, f He described with con-
siderable detail the lithological characters of the Lorraine series, and figured
the following fossils as characteristic of the upper portion : Ambonychia
radiata, Cyrtolites ornatus, Trinucleus concentricus, Strophomena alternala
Modiolopsis modiolaris, Orthoceras cequalis, Avicula demissa, and Orthis tesiu-
dinaria.

Reference is again made to the Lorraine series in a general description of
the New York formations in 1847.J In speaking of the term Hudson River
group, he says : §

" The only reason assigned for the name was that this subdivision presented certain
peculiarities arising from a disturbance it had suffered along the Hudson river. The
Hudson river region, however, presents no facilities for the examination of the upper
part of the Lower Silurian ; it is only at Lorraine or Pulaski, in the neighborhood
of Rome, in New York, that this part of the series can.be examined satisfactorily."

As geologist of the third district of New York, Mr. T. A. Conrad described
and named in his first report on the district|| the " Gray Sandstones and

Shales of Salmon River," or the series of alternating layers of gray sandstone
and dark lead-colored, friable shales situated above the limestone of Trenton

* Loc. cit, p. 264.

t Geol. N. y., Survey Second Geol. Dist., 1842, p. 119.

JAgric. N. Y., vol. 1, 1847, pp. 134, 135; and again in his American Geology, 1856 : ami in the little
Manual of Geology of 1859-60.

I Am. Geol., vol. 1, pt. 2, 1856, p. 125.
I 1837, p. 164.

342 C. D. WALCOTT — THE TERM "HUDSON RIVER GROUP."

Falls and beneath the red or variegated sandstone of Niagara river. He used
the same nomenclature in his annual reports for 1838 and 1840 ; and in a table
showing the classification of the New York rocks, published in 1*40,* he
used nearly the same scheme of classification except to place the Hudson
slate, characterized by graptolites, beneath the Calciferous and Potsdam
sandstones, thus anticipating the view subsequently published by Emmons,
and in part adopted by Logan and followed by Hall in 1862. By priority
of publication and completeness of definition, Conrad's term should have
been accepted and used instead of Hudson River or Lorraine. Why it was
not adopted by the New York state geologists remains unexplained.

In proposing and defining the term Nashville group,f Professor J. M.
SafFord stated that the line of demarkation between the Trenton limestone
and the Hudson River rocks above was not clearly defined, owing to several
species of the fossils of the Trenton running nearly to the top of the Hudson
River rocks, and those of the Hudson River rocks extending down nearly to
the base of the Trenton. In his table, the Nashville group is made to in-
clude the Hudson River and Dtica slates, and the central and upper portions
of the Trenton limestone. This view was republished in the first biennial
report of the State survey in 1856. In the final report the classification
was reviewed;^ all the Trenton beds were united under the term Trenton ;
and the Orthis bed was considered as the base of the Nashville formation on
account of carrying the very characteristic species, Ambonychia radiata and
Oyrtolitea ornotus, also, Rhyuchonella modesta and 11, capax. Professor
SafFord .says:

" On such grounds we make the bed in question Hudson River, and lix the equiva-
lency of the entire Nashville formation."

The Nashville formation is assigned a thickness of about 450 t'v^t, and it
ig delimited below by the Trenton limestone and above by the Niagara
limestone.

Under the title of "Hudson River group," Professor James Hall, describ-
ing the shales occurring between the Galena limestone and the Niagara
Limestone in [owa, mentions certain .shales on the Little Maquoketa river
which were referred to the Hudson Kiver group.§ It is stated that the
section is scarcely more than twenty live feet in thickness, ami that on the
opposite side of tie- river the entire thickness is probably less than 7") feet.

In the second geologic survey of Iowa [| the classification adopted refers
the rocks described a- the Hudson River Bhales by Professor Hall to the

•Am. .I"iir. Sri., vii I. 88, 1840, p, 90.

t I'm--. Am \ idr. Set., rol 7, 18 ■. p, i

logj of I .-nil. - . ■•, 1880, p|
. leol Survey Iowa, rol. i, i-e I, i -
Ki-|i-.ii oi-i.i. Surrey Iowa, rol, I, 1870, by < lhai lea \. White, p. I

THE MISSISSIPPI VALLEY EQUIVALENTS. 343

Cincinnati group, under the name of Maquoketa shale. The formation is
referred without reserve to the same geological series as the rocks at Cincin-
nati, Ohio. The author considered the section as a local or partial develop-
ment of the Cincinnati series, and on that account proposed the name of
Maquoketa. He was also influenced by the decision of Messrs. Meek ami
Worthen, who held that the Hudson River groups in Indiana, Ohio, Illi-
nois, etc., were not equivalent to those of the Hudson series to which the
name of Hudson River shales was first applied. A number of species oi
fossils were found that are also common to the Cincinnati formation.

In Professor S. Calvin's description of a deep well drilled at Washington,
Iowa,* it is stated that at 702 feet a fine bluish or greenish shale, identical
in all respects with the shales of the Hudson River group as seen in the
gulch at and below Bellevue, Iowa, continues down to the depth of 793 feet,
giving a thickness of 91 feet. This group of shales is plainly referable to
the Hudson River shales of Hall or to the Maquoketa shales of White. In
some " Notes on the Geology of Southeastern Iowa," C H. Gordon |
describes the strata passed through by a deep well at Keokuk. In this
section the Maquoketa shale has a thickness of 63 feet.

During the field season of 1889, a collection of fossils was made from the
typical Maquoketa locality by Professor Joseph F. James, of the U. S. Geo-
logical Survey. Of 41 spsciesj collected aud identified, all but seven are
identical with those found in the fauna at Cincinnati. Stratigraphicallv,
the Maquoketa shale is a diminished representative of the section at Cincin-
nati, and it is also identical in its lithologic and paleontologic characters.

* Notes on the formations passed through in the boring of the deep well at Washington, Iowa :
Am. Geol., vol. 1, 1888, p. 29.
f Am. Geol., vol. 4, 1889, p. 237.

i Montindipora gracilis. Orthis < maa rata.
" lens. " fissicosta.

" quadrata. " 'occidentalis.

Streptelasma eormeulum. " testudin

Diployraptus amplexicaule. Zygospira modesta.

'" putillus. I'1, rinea demi

Heterocrinus kcterodact>ihi<. Cleidophorus negleetus.

Poroerinus crassus. 'I) llinomya obliqua.

IAchenocrinus erateriformis. Nucula fecunda.

Fenestella, sp. Eyolithei parviuscu
Paleschni'i maculata. leolus (.'), sp.

Lingulella eineinnatiensis.

Lin'gula coburgensi RaphUtoma micula (subtili triata).

daphne. Ti ntacu '

" modesta. Murehisonia gracil
" pro-'

" a- hit fieldi. Pleurotom rata.

,,,,, r,7osa. Orthoeeras son

Trematis, sp. Plumulites /"//".v.

Leptaena serieea. Beyrichia, sp

Strophomi na alternata. Aeidaspia crosoiu

rhomboidalis.vsLr tenui triata. Calyinene callicephala.

Orth;.< biforata. ' ' '"'"•

XLV— Bun.. Geol. Soc. Am., Vol. 1, 1889.

( iHBONOLOGY OF N A M I B.

The chronologic arrangement of the names given to the series ot nicks
under consideration is as follows:

Salmon River ; ( lonrad, L836.
Hudson River ; Mather, 18 I".
Lorraine ; Emmons, 1*42.
Nashville; Safford, L853.
Cincinnati; Meek and Wbrthen, 1866.
Maquoketa ; White, 1870.

I >I8< OVERIEg OF R] :< l.\ I Vi.AKs.

The discovery of fossils other than graptolites in the dark shale- or Band-
stones of the Hudson River group below Albany has been infrequent. Mr.
T. Nelson Dale found a few species al Marlborough, about ciirht miles south
of Poughkeepsie, in 1879, and Mr. NTelson II. Darton found a few Trenton-
Hudson species twenty-one miles south of New burgh, in 1885. < >n the east Bide
of the Hudson, Mr. Dale discovered, in an argillaceous schist near Vassar
1 liege, an assemblage of fossils much like thai reported by Mr. Darton in

Orange county. The species range in the Trenton Limesl ■ and also in the

upper part of the Beries in central New Vm-k. Mr. Dale Bays of them:

•■ The occurrence of these fossils in these localities would then establish the fact that
the gray slates and shales in the vicinity of Poughkeepsie, on both Bides of the river,
are ■ rous, and that they very probably belong to the Hudson River group, as

indicated by Mather in I848j certainly, to some member of the Trciii.ni period.
i facts also speak in Eavor of the retention of the terra Hudson River group, as

advocated by Hall."

The mosl important discovery of fossils in the Hudson Beries, however,
was thai made by Mr. C E. Beecher in the beds near the Dudley observa-
tory, a shorl distance west of Albany."] The fauna included 26 species; and

.in. Jour - 17,1-7'

i- from in exposure oj the Utloa slate and associated rooks within tin-
inv (36th Ann. Ri i v v State Mua. Nal Hisl . i-

/' (a,

"
/ ,m.

a of Billing

• •f lamellibranchl

THE SHALES WEST OP THE HUDSON. 345

it is, as a whole, characteristic of the upper portion of the Utica shale in
the Mohawk valley and of the passage beds between the Utica shale zone
and the lower portion of the Lorraine shales in the section at Lorraine,
Jefferson county, New. York.

Professor R. P. Whitfield concluded from his study of the graptolitic
fauna at Norman's kill, uear Albany, that the graptolite-bearing layers there
are of the age of the Utica shale. He mentions four or five species of grap-
tolites that are common to the Norman's kill fauna and the Utica shale in
the valley of the Mohawk.*

When studying the strata on the east side of the Hudson valley, I was
brought in direct contact with the disturbed strata that had been referred to
the Hudson River group by Mather and Hall, to the Taconic system by Em-
mons, and to the Quebec group by Logan. For the purpose of obtaining a more
intimate knowledge of the strata assigned to the Hudson River group
west of the Hudson, I began by examining, during the field season of 1887,
the contact of the Trenton limestone and Utica shale at the falls of the
the Hudson, near Sandy Hill. This is the only point known to me where an
undisturbed contact is shown between the Trenton limestone and the shales
of the Hudson river valley. From this point the shales may be traced,
with little interruption, to the neighborhood of Albany, where they are
very much disturbed and stand at a high angle. In this vicinity the
noted graptolite beds of Norman's kill occur ; also the locality where Mr.
Beecher discovered the upper fauna of the Utica shale zone. Following up
Norman's kill, alternating shales and sandstones are passed over, all of
which are highly inclined to the eastward. Crossing the line of disturbance,
the shales and sandstones, of precisely the same lithologic character, are
met with in a horizontal position. This series may be followed up until the
superjacent Lower Helderberg limestone is met with, resting conformably
upon the sandy layers capping the section of the Hudson series.

At the Indian Ladder, a few miles west of Albany, about 300 feet of the
Hudson series is shown in the section. The rocks here consist of alternating
shales and sandstones. Near the summit a massive belt of sandstone,
thirty feet or more in thickness, occurs just beneath the Tentacidite limestone
of the Lower Helderberg. This sandstone and the sandstone beds inter-
bedded in the shales are the grits of the older writers. The only fossils I
found at this locality were Orthis testudinaria and Trinucleus co7icentricus.

At Knowersville, about seventeen miles from Albany, the Lower Helder-
berg limestone is conformably superjacent to the Hudson shale. The section,
so far as it goes, is essentially the same as at the Indian Ladder. In ex-
plorations for gas in Albany county, a deep well was drilled at Knowersville,

* Reports upon the Geographical and Geological Explorations and Surveys West of the 100th Me-
ridian, under Wheeler, vol. IV, 1875, pp. 19, 20.

346 C. D. WALCOTT — THE TERM "HUDSON RIVEB GROUP."

starting 595 feet vertically below the base of the Lower Helderberg limestone.
It is reported that the strata passed through were gray shales and alter-
nations of gray and black slates, which in places were quite calcareous and
contained occasional thin beds of sandstone. At the depth of 2,**o feet.
the Trenton Limestone was struck ; adding to this the 595 feet of shales and
sandstones between the mouth of the well and the base of the Lower Helder-
berg limestone, we have a total thickness of 3,475 feet for the strata between
the Lower Helderberg and the Trenton limestone on the west side of the
valley of the Hudson.* This section is of great interest, as it proves be-
yond question that there is a great series of shales and interbedded sandstones
between the Lower Helderberg and the Trenton limestone in the valley of
the Hudson. If we go down the valley of Norman's kill until the upturned
rocks are met with, we shall have little doubt that the latter are equivalent
to a portion of the section passed through by the well. That the graptolite-
bearing beds of the Hudson valley are low in the section is proved by the
fact that no graptolites, with the exception of one or two wide ranging
species, are known in the upper portion, immediately along the base of the
Helderberg mountain.

If the geologist follows along the contact of the Hudson series with the
Lower Helderberg to the Schoharie kill, and then proceeds down the stream
to the valley of the Mohawk, he will pass over a large portion of the section
penetrated by the well, and, in the valley of the .Mohawk, find that the
series rests conformably upon the Trenton limestone, and that the base is
formed of dark Utica shales.

I next studied the strata on the eastern side of the Hudson, in Washington
and Rensselaer counties, and found a development of rocks characterized
by the graptolites of the Hudson terrane. They may be separated into
three divisions on the bases of lithologic character and geographic distribu-
tion: 1. The tlark argillaceous shales of the area between the western border
of the county along the Hudson river and the great fault that skirts the
western base of the range of hills separating the hilly country from the
low, tlat land of the river valley. 2. The Bilicious cherty bed.-, the green
and red .-lates. ami the dark argillaceous -hales that occur, associated with
them, over the central and interior portions of Washington county. •">. The
dark argillaceous -hale- and green hydromica schists of the still more eastern
Taconic range. There is not Bpace for a full description of the rocks.
They are largely formed of -hale- and sandstones and Bilicious slates, (lip-
ping to the eastward at an average angle of 10°. < mi<- Bection measured in
Greenwich, Washington county, -jive- a thickness of 2,600 feel ; the grapto-
lites occur loit feet and 1,700 feet above the base, and over the upper

I hi iting to theKnowen>vilIe and Knox wells are taken from h paper by Mr. Charli

urner "On the Petroleum and Natural Gas In New Vorh State," 1888, pp. i-

THE SHALES IN THE MOHAWK VALLEY.

347

graptolite beds lie the red roofing slates. At one locality 8 genera and 13
species of graptolites were found, all of which are identical with those found
at the Norman's kill locality.* The strata of the Hudson terrane cannot
be delimited clearly, as the base and summit of the series are not shown on
the east side of the river. I have estimated the upper division, composed
of cherts and shales, and green and red roofing slates, at 3,000 feet; and
the lower division, composed of calcareous sandstone and shale and dark
argillaceous shales, at 2,000 feet, which gives a total thickness of 5,000 feet
for the Hudson terrane on the east side of the river.

In tracing the Hudson terrane westward in the valley of the Mohawk it
is found that the Utica shale and the lower slaty portion of the Lorraine
section occupy the entire section between the Trenton limestone and the
Oneida conglomerate. At Utica, the Utica shale is 710 feet in thickness*
and the entire upper portion of the Hudson terrane, consisting of shales and
sandstones in Albany and .Schoharie counties and of the same character of
rock in the Lorraine section, is represented by 90 feet of somewhat silicious
and, in places, sandy shale. At the section a little southeast of Utica, the
fauna is essentially that of the upper limit of the Utica zone in the Lorraine
section, and practically the same as the fauna discovered by Mr. Beecher
near Albany. The upper or true Lorraine fauna has not, to my knowledge,
been found to the eastward of this locality. At the city of Rome, fifteen or
sixteen miles west of Utica, the sandy beds become more frequent as inter-
bedded layers in the shale, and the fauna is larger and more like that of the
upper portion of the Lorraine section. f

The explanation of the absence of this upper fauna in the beds beneath
the Lower Helderberg limestone, in the Hudson river valley section,
appears to be found in the area of non-deposition of the upper beds in the
vicinity of Utica. That the fauna is not present in the valley of the Hud-

*Coenograptus f/racilis, Hall.
Didymograptus serratulus, Hal).

" Sagittarius, Hall.

Leptograptus subtenuis, Hall.
Dicellograptus divaricatus. Hall.

" m.s, Hall.

Dicranograptus ramosus, Hall.

" furcatus, Hall.

Climacograptus bicornis, Hall.

pp. undt. (occurs at Nor-
man's Ki!l).
Diplograptus pristis, Hall.

spinulosus. Ball.

whitfieldi. Hall.

Germs, 2, occurring also at Norman's Kill.

fThe following species constitute the fauna found at Koine, New York

I)* ndrograptus simpler, Walcott.

Pala aster, sp. ?

Heterocrinus heterodactyb's. Hall.

h, oequalis, Hall.
Crania, n. s-p.
Pliolidops subtruncata, Hall.

"inta, sp.
LepUrna sericea, Sowi rby.
Orthis testudinai ia, Dalman.
Am'- adiata. Hall.

Modiolopsis modiolaris. Hall.

" anodontoides, Hall.

" curia. Hall.

" faba. Hall.

" cana llata, Walcott.

Avicula iasueta, Conrad.

Cleidophoi us planulaius, < lonrad.
Orthodesma parallelum, Hall.
Tellinomya levata. Hall.

1/ i eh ■ 1 711 '"' I, Hall.

■ at* lliformi8, Hall.
Bcllerophon bilobatus. Sow erby.

" (cancetlata) texti Hall.

Cyrtolites ornatus, Conrad.

Plumulitt Hal I ami \\ hitfield.

Acidaspu U mi . Hall.

thrus bi '■'.". Green.
Asaphus finiiir, phi - ■■«.
fail/,:,, m calticephala, < Ireen.
, Katon.

348 C. D. WALCOTT — THE TERM "HUDSON BIVEB GROUP."

3on is fairly well established; that it is present in the Mississippi valley or
the interior of the continent is well known. The barrier that prevented the
fauna of the interior sea from extending into the valley of the Hudson
during the Later part of the Hudson period appeals to have been a shallow-
in lt <>f tin- sea through central New York about the time of the deposition of
the passage beds between the Utica shale and the Lorraine shales, as shown
in the Lorraine section. To the west and north of Rome, the Hudson ter-
rane increases in thickness; and at Lorraine, in Jefferson county, I measured
the following section the past summer:

Section along the south branch of Sandy creek, Jefferson county, N. Y.

Feet.

1. Trenton limestone as exposed in the town of Ellisburgh__ !'■">

2. Dark bituminous shale in bands, alternating with a smoother lead-colored

shale. Thin layers of a gray, fine-grained, calcareous sandstone occur at
various horizons in the shale. This shale is characterized by the fauna of
the Utica shale* 180

Fossils: Endoceras proteiforme, Triarthrus beckii, and Trinucleus
concentricus. At 150 feet up in the shales a few minutes' work of collect-
ing gave: Leptcena sericea, Orthis testudinaria, Cleidophorus planulatus,
Tellinomya, sp. und., Triarthrus beckii, and Trinucleus concentricus.*

3. Alternating bands of shale and gray, fine-grained, calcareous sandstone ; the

shale predominating 100

Fossils: Diplograptus pristi», ERppothoa inflata, Palesthara (sp.
undet.), Monticulipora (2 sp. undet.), Pholidops cincinnatiensis, Tre-
matis terminalis, Leptcena sericea, Slrophomena alternate, Orthis tes-
tudinaria, Zygospir'i mud.^in, Avicula insucta, Modin/op.si.i <t,f<l<,ntoides,
Cleiodophorus planulatus, Xucula levata, Bellerophon eancellatus, Pleu-
rotomaria (small sp. undet.), Endoceras prof' iforme, Triarthrus hen'
Calymene eallicephala. At the summit of this belt I found : "Pholidops
subtruncata, Leptcena seriea, Orthis testudinaria, Cleidophorus planula-
tus, Ambonychia radiata, ami Triarthrus heckii. f

I. Gray, line-grained, calcareous sandstone, with partings of black and drab
-ha]'-.: yielding on Sandy creek the folio wing fauna: Leptcena se Stro-

phomena alternata, Ambonychia radiata, Modiolopsis modiolaris, Cleido-
phorus planulatus, and Calymene eallicephala. On tin; Salmon river, at
Pulaski, Oswego county, the base of tin- series i- Been ami about fifty I
of strata. Fossils are abundant, but as they are better preserved in the
drift to th<- south in Lewis ami Oneida counties, the following typical
species only were collected: Monticulipora diseoidea, M. gracilis, <'rt< i-
ana G yptoerinusdecadactylus, Leptama sericea, Strophomena alternata,

Ambonychia radiata, Modiolopsis modiolaris, Nucula levata, Cleidophorus
planulatus, Cyrtolites ornatus, CornuUtes curvatus, ami Calymene ealli-
cephala. At Salmon river fall- the -uii i in it uf this series i- seen jusl above

the line '•{ lie- Motion, Ihe fir* I folly f'-.-t "I lie' ibale i- < •< > 1 1 • ■< • :it < • « 1 by drift ilep'ixitx, lilll ell

ttii' inch ••( Sandy creek may be seen in numeroux expoaun

; 1 1,1- i- the big heal Bone lit which / und.

the line ol Sandj Mouther of this series of rock exposed.

SECTION ON SANDY CREEK. 349

Feet,
the falls, and 130 feet of strata are shown at the falls and below. The

strike of the beds at Pulaski and at the falls is nearly the same, and the

difference of altitude between them is 320 feet. Adding the thickness of

the exposure at Pulaski to the supposed concealed thickness (320 feet) and

the thickness at the falls (130 feet), we have 300

Fossils: This belt is characterized by the upper Lorraine fauna, as
represented by the following species : Orthls testudinaria, Modiolopsis
modiolaris, Mar chisonia miller i, Cyrtolites ornatus, etc. From the drift
blocksof the division there have been collected: Monticulipora discoid V a,
M. lens, M. mamillata, M. (2 sp. undet.), Glyptocrinus decadactylus,
Leptama sericea, Lingula quadrata, Orthis erratica, 0. biforata, O. oeci ■
dentalis, 0. testudinaria, Bholidops subtruncata, Stropkomena alter nata,
S. alternata var. nasuta, S. tenicistriata, Ptilodictya (sp. undet.), Belle-
rophon bilobatus, Cyrtolites ornatus, Mxirchisonia bellacincta, M. gracilis.
M. milleri, Plenrotomaria subconica, P. trophidophora, Raphistoma len-
ticulare, Endoceras (sp. undet.), Orthoceras (4 sp. undet.), Ambonychia
radiaia, Avicula demissa, Cleidophorus planulatus, Lyrodesma poststria-
tnm, L. pulchellmn, Modiolopsis curta, M. faba, M. nasuta, M. modio-
laris, M. pholadiformis, M. truncata, Orthodesma contract urn, 0. paral-
lelum, Conchicolites Jtexuosus, Acidaspis (sp. undet.), Asaphus platy-
cephalus, Calymene callicephala, and Trinucleus concentric"*.

5. Gray sandstone 30

810

The basal beds of gray sandstone are not seen in continuous outcrop be-
tween Salmon river falls and the Medina sandstone. At Fultonville, Oswego
county, a well passed through the Medina, and thence through the gray
sandstone and Lorraine shales to the Trenton limestone. The record of the
well gave:

Medina sandstone -
Lorraine sandstone and shales -
Dark shales (Utica)
Trenton limestone -

2,050 "

This result indicates a thickness of 1,000 feet for the rocks of the Hudson
period in northwestern New York, and the measured and estimated Bections
give 8104- feet, to which there is to be added the thickness of the sandstone
beds beneath the red Medina sandstone.

Comparing these sections with that of the Hudson valley, they are found
to be less than one-third of its thickness ; but they are characterized in the
same manner, in the upper portion, by interbedded sandstones and <:ilc:uvoii>
sandstones alternating with shales, and in the lower portion by a consider-
able development of dark argillaceous shales. Comparing the fauna, \\c find

400 feet

880

120

650

350

C. D. WALCOTT — THE TERM HUDSON RIVER GROUP.

thai the forms of the upper part alone of theUtica zone occur within the valley
of the Hudson, and that the -ivat jrraptolitic fauna of the Hudson valley is
largely unknown in the interior of the state. It is probable that the grapto-
litic fauna was prevented from spreading over the interior <>f the Btate by
some such harrier a- subsequently excluded the interior continental fauna of
this period from the valley of the Hudson.

A- described by Professor Orton, in the sixth volume of the Geological
Survey of Ohio, published in 1888, the Hudson River group in southwestern
Ohio consists of alternating beds of limestone and shale, the latter of which
is commonly known as blue shale. The entire thickness of the series in
southwestern Ohio is aboul 750 feet. He divides the series into lower and
upper. The lower is known as the Cincinnati division, and the upper as the
Lebanon division. The Cincinnati division has a thickness of from 425 to

HUDSON

Lorraine

. ---'

UTICA

LORRAINE

I III. II, I, ill.

CINCINNATI

MAUUOKETA

Pioi bb I.— Diagram illustrating ■'■• ' ■ 11

.v< w York, Ohio, a < ' /■

• n- are arranged on this diagrai i the Bame relative scale, a description ol

will be found in the text. I number of section" are known between western Ohio and iowa,in
Illinois, thai show n gradual thioning of the Hudson toward the northwest.

150 feet, and the Lebanon division he fixes at aboul 300 feet. The divis-
ion- are separated on both paleontologic and Btratigraphic grounds. In
drilling for gas in the vicinity of Find lay, the CJtica Bhale was rael with at a
depth of 800 feet. Ii is a black .-hale containing one of the si character-
istic fossils of the Utica shale, viz., Leptobolus insignis. This bedol Bhale has
the normal thickness of the Utica shall- in New York : i. '., 300 feet. The
LJtica shale thus discovered and defined is a constant element in the deep
wells of northwestern Ohio. Its upper boundary is not always distinct, as

the Hudson River -hale that overlies it - stimes graduates into it in color

and appearance. No great falling off of black -hale appears iii the Dayton
well, but at Middletowa the driller reported a sharp boundary between the
gray -hale, 320 feel thick, and black -hale 100 feel thick: the latter

THE OHIO EQUIVALENTS. 351

directly overlies the Trenton limestone. At Hamilton the same driller re-
ported the boundary at forty feet, and the black shale was here reduced to
thirty-seven feet, according to his record. From these and similar facts it
appears that the Utica shale is much reduced and altered as it approaches
the Ohio valley, and is finally lost by the overlap of the Hudson River shale
in this portion of the state and to the southward.

A comparison of the fauna as obtained at Lorraine with that of the Cin-
cinnati section shows nearly all of the Lorraine species at Cincinnati; also,
that they have relatively the same range in the section. This comparison
has been made in a tentative way, but so far as it has gone it shows a sur-
prising equality in range of species in the two sections. Comparing the
section at Lorraine, as I have already stated, the fauna of the passage-beds
from the Utica shale zone is almost identical with that of the zone discovered
near Albany, which, from the general character of the strata in the valley of
the Hudson, I presume to be at about the same stratigraphic horizon in the
section.

Value of the Term.

The use of the name Hudson River group has been attended with more
or less uncertainty ever since it was promulgated by the geologists of the
New York Survey. Of the board composing that .Survey, Dr. Mather, Mr.
Vanuxem, and Professor Hall favored the use of the terra, while Dr. Emmons
used Lorraine and Mr. Conrad, Salmon river, for the same series of rocks-
This uncertainty was further increased in 1862 by the statement of I'm lessor
Hall that the term Hudson River group could not be extended to include
the rocks of central and western New York and the Ohio valley between the
Trenton limestone and the Upper Silurian rocks. Under the influence of
Professor Hall's withdrawal of the term, Messrs. Meek and Worthen pro-
posed, in 1865, the use of the name Cincinnati, saying:

"As it is now acknowledged that the rocks along the Hudson river valley, to which
the name ' Hudson River group' has been applied, belong, as long maintained by Prof.
Emmons, to a different horizon from the so-called Hudson River recks of western
New York and the states further westward, it seems to be an awkward misnomer to
continue to apply the name 'Hudson River group ' to these western deposits. In Bub-
divisions, it is true, have received various lithological names, such as Utica Slate,
Frankfort Slate, Lorraine Shale, etc.; but as each of these names w i 11 probably be
always directly associated in the minds of geologists with the particular subdivision
to which it was originally applied, while neither of them is applicable to the lithe-
logical characters of the whole series, we cannot, without creating confusion, bo ex-
tend its signification."*

The term Cincinnati group was adopted by the geologic surveys of Illi-

* Proc. Acad. Nat. Sci. Phil., vol. 17, 1866, p. I
XLVI— Bull. Geol. Soc. Am., Vol. l, 188».

352 C. D. WALCOTT — THE TEEM "HUDSON RIVER GROUP.

nois and Ohio, ami came into general use in the west. Borne geologists, how-
ever, preferred to use the term Lorraine, as proposed by Dr. Emmons, on
the ground of priority; and when, in 1877, Professor Hall stated that he
had been led into error in considering the rocks in the valley of the Hudson
as of primordial age, or older than those of the Lorraine and Cincinnati sec-
tions, and that be thought the term Hudson River group should he used in
geologic nomenclature, as it had specific value, the tendency to return to the
use of the name became more and more apparent among geologists. At
the same time, however, some geologists continued to use the name Lorraine;
others retained Cincinnati, and in Iowa, Maquoketa was used.

Wishing to know more of the typical rocks included under the name
Hudson River group by Dr. Mather in his survey of the Hudson River
valley, I examined the sections both on the west and on the east sides of the
liver, with the result which I have already recounted. I then examined
and studied carefully the sections at Lorraine, on the Salmon river, and in
the Mohawk valley; and on returning from the field I read the descrip-
tions of the supposed equivalent series of rocks as found in Ohio and por-
tions of the Mississippi valley.

The result of this study is the retention of the term Hudson* for the series
of strata between the Trenton limestone ami the superjacent Upper Silurian
rocks. The sections in the valley of the Hudson embrace all the strata be-
tween the Trenton limestone and the Upper Silurian, and include the Utica
Bhale formation, the intermediate silicious slate, as represented by the lower
portion of the Lorraine shales, and also the alternating sandstone and shales
of the Lorraine section. It is true that the typical fauna of the upper por-
tion of the series is not present in the valley of the Hudson bo far as known ■
but we iiiu.-t recollect that stratigraphic geology preceded paleontology and
the identification of horizons by paleontologic evidence, and that when by
practically continuous stratigraphy a formation has Keen traced from one
area to another the name applied to the formation where first discovered
and named \sill hold good even though the rocks at the typical locality do
not contain the fauna u liich characterizes the horizon at some other locality.
The absence of a fauna in such a case does not injure the correlation : its
presence would of course strengthen the correlation, but in the case in hand
it do<- nut appear to be essential.

In thus adopting the term Hudson for the entire Beries, I do not wish it
understood that I favor dropping the local name- Lorraine, Cincinnati,
Maquoketa, etc. The term Hudson is used in the generic Bense, to include
a group of formations that occur between the Trenton limestone horizon

• ■■! the original Dame it dropped In order t" bring il Into harmony with the
n, Chazy, Niagara, etc.) tnd adapt ii to it- position • Ic term

DEFINITION OF THE TERM "HUDSON

. >>

.. - . >

and the Upper Silurian or Niagara horizon. This idea is expressed in the
following tabulation :

Terrane.

Formations.

Hudson - - - J

i
i

.. .

Hudson River shales and grits. Utica shale.

Frankfort shale.

Lorraine shale and sandstone.

Salmon River sandstone and shale.

Cincinnati shale and limestone.

Nashville shale.

Maquoketa shale.

In tabulating the formations in this manner the local names are preserved
and, at the same time, the position in the geological series is indicated by
the term Hudson. Thus, in speaking of the Hudson rocks in western New
York, we say the Hudson terrane consists in Lorraine of the Utica shale,
the Lorraine shale, and the Lorraine sandstone ; and, on the Salmon river
of the Salmon River shale and sandstone, and the Pulaski shale.

In reply, then, to the question, " What is the value of the term Hudson
River in the light of recent geologic research," I think we may say that its
essential part is established by the rules of geologic nomenclature, except
against the prior use of the name Salmon River. In relation to this, I think
all geologists will agree that the interests of geology will be subserved by
leaving the term Salmon River in the obscurity in which it has so long re-
mained. The term Hudson has a clear and distinct meaning. It is known
in the geologic nomenclature of America and Europe, and it is sustained by
the testimony of the rocks in the valley of the Hudson.

DISCUSSION.

Professor James Hall: I .should like to express my great gratification
with the results of Mr. Walcott's iuvestigations. It leaves nothing, I helieve,
now to be desired beyond the bringing out of detailed results, which I dare
say he will do in the future.

Professor W. M. Davis: This discussion gives me a desired opportunity
to explain a small matter, since I fear that a position I took several years
ago bearing on this question has been somewhat misunderstood. Some
time ago, when visiting the Hudson river valley with a class of students in
our Summer School of Geology, we examined the relations of the Hudson
River rocks and the overlying Helderbergs. The question of the relative
conformity of these two divisions had been much discussed, and we sought to see
how far the evidence there bore upon it. There are several sections, one
particularly on the Catskill stream not far from the town of Catskill, that
give fair opportunity for close examination of the lower and upper rocks.
My conclusion at that time was that, as far as that district was concerned, it
would be unsafe to say that there was a distinct unconformity between these
Hudson river rocks and the overlying Helderbergs. I did not wish to
assert that there was absolute conformity, but it seemed to me that with the
facts at Catskill alone it would be difficult to demonstrate unconformity;
that if there were at all other localities a perfect conformity, the observations
at Catskill need not disagree with that relation ; that the difference of alti-
tude of the lower and upper rocks about the Catskill was a discordance such
as might be produced by the folding together of the dissimilar rocks in that
region — the amount of discordance not being more than is often observed as
the result of folding masses of unequal resistance. But, on the other hand,
at Rondout, farther down the Hudson valley, it is manifest that there is a
strong unconformity, and I should not wish for a moment to use the obser-
vations at Catskill as proving a conformity at Uondout or anywhere else.
The point is that, as far as Catskill is concerned, the facts do not compel the
belief in the unconformity of the Helderbergs to the Hudson formation, and
that if no other locality of contact of these formations were known, their
relation might still be in doubt.

Mr. Walcott: I have read Professor Davis's papers with interest and
profit, and I understood him to mean that the conformity between the two
series was only in the Catskill region, ami that there was an unconformity
at Becraft's Mountain, from the latesl paper published by him I obtained
tin- impression that he supposed a conformity to exist also at one of the sec-
tions in Rondout. I may have misinterpreted his description.

(864)

NIAGARA FOSSILS EAST OF THE HUDSON. 355

Professor Davis : At Rondout there is a very striking outcrop of the
Hudson formation dipping at a steep angle to the east, with the Coralline
limestone upon it dipping at a tolerably steep angle to the west, and fitting
into deep inequalities of the beveled surface of the under formation. The
contact could not have been made by a fault ; it was a distinct unconformity.
Intermediate between Rondout and Catskill I have found a valley where
the structure of the two rocks is clearly discordant — so much so that one
could hardly ascribe the discordance to the uneven folding of rocks of dif-
ferent resistance. On goiug up the Hudson valley beyond Catskill to the
Schoharie region, the Hudson and Helderberg rocks seem to be conformable,
both being essentially horizontal ; but the outcrops near their contact are not
very extended ; an unconformity by erosion might escape detection there.

Mr. Walcott : In this connection I wish to place ou record a recent dis-
discovery of Niagara fossils* in the tilted and upturned strata east of the
Hudson, in the township of Cambridge, Washington county, New York. The
section at this point consists of a mass of dark shales with interbedded chert,
and small lenticular masses of limestone in which the fossils occur. The
stratigraphic relations of this mass of rock to the strata of the Hudson terrane
to the west were not ascertained. This discovery is of interest, as it proves
that in this area of disturbance, unconformity, and usually of apparent non-
deposition of the rocks of the Niagara age, there was one tract in which the
Niagara fauna existed, became imbedded, and was not removed by subse-
cpient erosion.

* Orthis Jlabellum, Sowerby ; Ort his, 2 sp. undet. ; Leptaena transversalis. Hall ; StrophomeiM rhom-
boidaHs, Wahlen ; Rhynchonella negleeta. Hall: Merisla dubia. Hall ; Ceraurus, of the type of C.in-
signis (Beyrieh) Hall, and Ittcenus (fragment of head).

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA

VOL. 1, PP. 357-394

SOME RESULTS OF ARCHEAN STUDIES

ALEXANDER WINCHELL, A. M., L.L. D., F. G. S. A.

PROFESSOR OF GEOLOGY AND PALEONTOLOGY IN THE UNIVERSITY OF MICHIGAN

WASHINGTON

PUBLISHED BY THE SOCIETY

April, 1890

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA
Vol. 1, pp. 357-394 April 15, 189o

SOME RESULTS OF ARCHEAN STUDIES.

BY ALEXANDER WINCHELL, A. M., LL. D., F. G. S. A., PROFESSOR OF GEOLOGY
AND PALAEONTOLOGY IN THE UNIVERSITY OF MICHIGAN.

(Read before the Society December 28, 1880.)

ANALYSIS.

Page.

Conflicts of Opinion in this Field 357

The Northwest compared with New England ard Canada 359

Areas of Granitoid and Gneissoid Rocks_ 361

Areas of Crystalline Schists ^ 366

Structural Relations of the Granitoid, Gneissoid, and Schistoid Rocks 367

Mineralogical Relations of the Granitoid, Gneissoid, and Schistoid Rocks 374

Areas of Semi-Crystalline Schists 377

The Lithological Constitution of the System of Semi-Crystalline Schists 378

Argillite, with the Ogishke Conglomerate 379

Altered Tuffs and Mixed Rocks 381

Porphyrellite 382

Gniywacke 382

Structural and Mineralogical Relations of the Crystalline and Semi-Crystalline

Schists 383

The Uncrystalline Schists 385

Classification of the Foregoing Rocks 389

Discussion 391

Conflicts of Opinion in this Field.

The present memoir is simply a synopsis of facts observed by the author,
with a few obvious inferences, touching the structure and classification of
the older rocks of the Northwest. Citations will be made from other inves-
tigators where the facts or opinions appear to throw important light on the
problems which the author has studied.

The motive for offering this presentation of the results of personal studies
exists in the vague and conflicting state of opinion respecting the older rocks.
This concerns not only their genesis and geological history, but their con-
stitution and characters and even their sequence and mode of mechanical
relation to each other. On the one hand, there are geologists of reputation
who maintain that most granitic and gneissic rocks have originated directly
XLVII— Buj,l. <TF.or,. Soc. Am., Vol. 1, 1889. (357)

A. \VI\< 111:1.1. — RESULTS OF A.RCHEAN STUDIES.

from a state of molten fluidity : and this vim is extended even to the so-called
crystalline schists and t<> many other less crystalline rocks. On the other

hand, geologists of equal reputati ■egard the crystalline Bchists and gneisses

as ancient marine sediments, altered profoundly by the agents which have
acted upon them during the vicissitudes of terrestrial history ; and this view
is extended also to the granitic or massive conditions of the fundamental
rocks. Tlie representatives of the latter school, however, admit that extreme
metamorphic action has sometimes reduced the ancient sediments to a Btate
of igneo-aqueous plasticity, and that in such condition the materials have
been squeezed into fissures and spaces of diversified forms. They recognize
the fact that large volumes of marine sediments have probably consisted of
volcanic ashes, lapilli, pebbles, and larger fragment- which have been spread
over the ocean's floor by the same agencies and in the same manner as del 1 ital
materials derived from eroded land-surfaces; and they, equally with the
opposing school, discern the evidences that lava-like eruptions have occurred
in every age of geologic history.

What i- less to be expected than differences of opinion on speculative
questions like these is the great diversity of views respecting matters open
to observation. On the one hand, geologists of wide reputation and learning
contend that the entire series of pre-fossiliferous rocks constitutes but one
group or system. On the other hand, geologists equally competent recognize
an obvious division into two groups or systems, while some go to the extent
of characterizing not less than five systems beneath the oldest zone of life.
Those who recognize two or more pre-fossiliferous systems are nol agreed in
reference to their order of superposition. One maintains that the Montalban
i- below the Suronian, another that it is above. One affirms the Hastings
series to lie in the horizon of the Upper Laurentian, another places it in the
horizon of the Huronian. One recognizes Lower Laurentian in conformable
contact with the crystalline Bchists, another regards the rocks a< Upper
Laurentian. Systems in juxtaposition have to-day been pronounced con-
formable, to-morrow unconformable, and the next day again conformable.

items have been named as holding definite chronological sequence which

by others are affirmed to be but lithological states, having ihronological

significance.

With such a diversity of views entertained, not only within the deductive
1 >ii t also in the inductive province of the science, one can almost justify the
severe verdict of Whitney and Wadsworth, rendered after a searching
examination of the records of opinion found in American geological litera-
ture and thus -tated in their " Resume*: "

\V.- think tliat it i- impossible for any unprejudiced worker in tlii- depart nl of

nee !•> peruse with care the preceding pages and not feel obliged t" admit that the

logy of tion of tlii- country, and especially that of Canada and New

England, i- in an almost hopel tate of confusion. \\'<- think that it must have

THE OPINION OF WHITNEY AND WADSWORTH. 359

been made clear to the candid mind that the geologist would find himself completely
battled who should endeavor to obtain any definite knowledge of the real nature and
order of succession of the rocks which cover so large a portion of the region in question
from the study of that which has been published with regard to them. We believe
that we are justified in going still farther and saying that our chances of our having
at some future time a clear understanding of the geological structure of Northeastern
North America would be decidedly improved if all that has been written about it were
at once struck out of existence." *

We may do our predecessors the simple justice to admit that they have
beeu engaged ou difficult problems and have treated them with ability equal
to that employed by our contemporaries, and yet feel, with Whitney and
Wadsworth, that very much remains to be desired.

After the foregoing representation of the state of our knowledge of the
older rocks, it may appear presumptuous on the part of the present writer to
make an attempt where so many have fallen short of the success at which
they aimed. There are two circumstances, however, which lead the writer
to hope that he may be able to contribute something to a final understanding
of the structural relations of our pre-fossiliferous rocks : 1. He has had the
good fortune to study them over an area in which they lie apparently
in their original relative positions for hundreds of miles in uninterrupted
extent, while the older investigations have been conducted in the midst of
wearisome and perplexing convolutions, plications, and overturns. 2. He
has made his field observations for himself and has not depended on the reports
of subordinates ; and, besides earlier studies, he has spent recently the entire
working period of two seasons camping on the formations under investiga-
tion. It may be added that he has extended his researches into the fields
reported on by others and has collated the conclusions reached by them with
the facts observed by himself. He thinks, therefore, it will not be regarded
presumptuous to offer his contribution to the common stock of knowledge.

The Northwest compared with New England and Canada.

In most parts of the northern United States and eastern Canada, where
the oldest rocks present themselves at the surface, their condition, as repre-
sented, is that of more or less crumpled masses. In the Adirondacks the
granites, norites, and gneisses are thus characterized by Emmons,f though,
according to the methods of his time, the mineral constituents of the crystal-
line rocks were regarded more important than the structural features. In
Vermont the gneisses are reported by E. and C. H. Hitchcock as " exceed-
ingly contorted,"! insomuch that great difficulty exists in determining aver-

*" The Azoic System and its proposed Subdivisions," by J. D. Whitneyand M. E. Wadsworth, Bulletin
Museum of Comparative Zoology, Geological Series, Vol. I [pp. i-xvi and 331-505], pp. 519-520.
t Geology of New York, Part [I, 1842, 2d District, especially pp. 23 and 77.
t Geology of Vermont, Vol. I, 1861, p. 518.

360 A. WTNCHELL — RESULTS "l AJtCHEAN STUDIES.

strikes. The late survey of New Hampshire is apparently compelled to
limit itself largely to a Btudy of the surface distribution of the crystalline
rocks. It seems to be impossible to grasp the general structure in one con-
ception. In the pages of description little use is made of phenomena of dip
and Btrike. It is true thai pages are devoted to tables of dip and strike, but
they stand a- Isolated and meaningless facts. The neglect to unity them in
a structural conception is apparently due t<> the extreme difficulty of the
task. There is little persistence of dip or continuity of strike. The figures

in contiguous regions are as diverse as can be c seived . In the midst ol

this bewildering chaos Professor Hitchcock has recognized certain generali-
sations which lie on the road to a correct interpretation, but it was impos-
sible, in the light of facts then in possession of geologists, to follow their
leading to a full solution of the Archaean problem. To these I shall refer on
some Bubsequent occasion.

The intricacies of rock-arrangement through western Massachusetts are
represented in the conflict over the Taconic question, the Bounds of which
have not yet ceased to reverberate. These obscurities were traced by the
brothers Rogers into Pennsylvania and Virginia. In eastern Massachusetts
the lithologic arrangements are so ambiguous that the able geologists who
live upon them are undoing each other's schemes of interpretation with a
zeal and emphasis which would seem to imply that opposites must both and
all be true. In the Canadian field the remarkable structural investigations
of Sir William Logan and his co-laborers have long since shown a state of
disturbance which sets all method at defiance. The truth of this is illus-
trated in almost every annual report published from 1842 to 1866.

Quite in contrast with these structural complications is the lithologic Bys
tern of northeastern Minnesota. From Vermilion lake to South Fowl lake
the semi-crystalline Bchists pursue a Btrike varying little from east-northeast
for a distance of twenty ranges of townships, or about 130 miles along the

strike. Beyond this they extend, largely <• sealed by overlying pre-Silurian

rocks, in the same genera] direction to Thunder bay, 15 miles further.
Throughout tin- distance the schi>t> present hut a single told, and their
structural relation- to each other and to the crystalline schists and gneU

of higher antiquity bee ■ a matter of comparatively easy observation. In

tin- regions west and northwest of Vermilion lake, at least as tar a- tie- Lake
of tin- Woods, similar simplicity of structure prevails, though, so tar a- I
know, there is no other area of equal extent in whioh a single system of dip-
ami striki - persists throughout.

i ii Bltehcocl and J. H. Hunting! '■ I. II. 1877. chapi r to *,

pl.xxl, p coroplejfiv <>( tho

e<] in the tweli llona acroa* the State shown In the Vila- rlbed in

Vol li. i In the numerous and i < -'•' forth In the

• i lie Bui i ■

Areas of Granitoid and Gneissoid Rocks.

The rocks which on the evidence of relative position would he regarded
as the oldest rocks accessible to observation in the Northwest are granitoid,
as every one understands ; but I have not found, as yet, any general grani-
toid nucleus of the continent, occupying the surface uninterruptedly, in any
direction, for more than a hundred miles. Even the granitoid areas are not
occupied chiefly by rocks conforming to the standard defiuitiou of granite —
a non-bedded and non-foliated mixture of quartz, feldspar, and mica, or of
quartz, feldspar, and hornblende. Limited areas approaching, or perhaps
attaining, this condition are found ; but the principal expanses of crystalline
rock are gneissic— consisting of quartz, feldspar, and a dark element, with
the quartz in many cases deficient in amount, but also very extensively
disseminated in porphyritic development. The feldspathic element is pre-
dominantly orthoclase, but generally one or more triclinic feldspars is also
present. The dark or ferro-maguesian element is generally biotite or horn-
blende, or both together. Sometimes muscovite appears with one or both of
these, and occasionally it excludes them. In rare cases the dark element is
augite* and not unfrequently individuals of hornblende are found with
augitic nuclei. Over considerable areas the hornblende has undergone
uralitization, and even chloritization. A large part of the hornbleude,
however, is black, lustrous, and fresh. The orthoclase is often found in por-
phyritic development, but generally it occurs in the ordinary granular state.
In the chloritic portions the feldspar is chiefly of late generation, and forms
a more or less perfect grouudmass, with a greenish stain in the vicinity of
the amorphous, chloritized hornblende. In mineralogical composition the
areas strictly granitoid are uudistinguishable from those properly gneissoid.
In structure the distinctions of successive generations are less obvious, and
the chloritization of the hornblende has made less progress.

Within the limits of northeastern Minnesota four distinct areas of grani-
toid and gneissoid rocks have been surveyed. The accompanying diagram
shows their relative positions.

These are the Basswood Area, the White Iron Area, the Saganaga Area,
and the Vermilion Area, so named from large lakes lying upon their borders.
Only the White Iron and Vermilion Areas have been followed along all
their borders. They are the only ones embraced wholly in Minnesota.

The White Iron Area is elongated from Snowbank and Disappointment
lakes south westward to Birch lake and beyond. It is overlain along its
southeastern border by the great gabbro formation ; and this, at one place,
laps quite across the Area, dividing its surface exposure into two areas.

* M. Alf. Lacroix has very recently made a study of pyroxenic gneiss from various parts of
Europe. "Contributions <> Vttwde des gn< - d,pyroxtoru rides roches a werneritt ," Paris, 1889, pp. 1-280.

(361)

..I.J

A. WINVHELL — RESULTS <>!•' ARCHEAN STUDIES.

Thia mass consists of hornblende gneisses, generally vertical, and Btriking
Dortheast. The orthoclase is reddish, and the individuals are mostly Large —
up to three fourths of an inch in diameter. Very rarely rauscovite is present,

and not more frequently biotite. The nature of the rock in places bei les

decidedly quartzose. A few pebbles of granulite and quartzite arc dissemi-
nated through it. This body <>f gneiss, or granitic gneiss, is everywhere
around t lit* Bhores of White Iron lake diversified l»v numerous inclusions of

Ki'.rm. 1. — D G mitoid and Ghteisaoid Area \ ;-'

mica and hornblende schist. This striking phenomenon 1 -hall refer to in
another connection.!

The Saganaga Arm of granitoid rocks hold- Saganaga lake, with its long
southern arm-- centrally located, and lies in Minnesota on the fourth and
fifth rang* - of townships, stretching north five or six miles across the into
national boundary, where it i< limited by semi-crystalline BchistS. Toward

the east-northeasl it extends into Canada an unknown distance, along a zone
north of Gunflinl and North lakes. This mass, as a whole, is distinctly a
quartz-bearing Byenitic gneiss. Ii is nowhere characteristically massive.
The quartz occurs throughout in Large angular individuals, attaining diame-

• in default •■! ompany the prenenl memoir ii maybe useful to mention thai the

.ill ink ---i in northeastern Mlnm onvenlently ihown on the map

Facing p. 418) of the Name* »l la

i untain l. ' ' Boutheaul ol I) to En i "< ir|. I.

.nin-i L." toOgiehke-muncie lake— the namen employed In the Minn.

n from the plate of the ' B i and Survey. A mor mplete map may be found

Hi Ann. Rep of the Minneeota 8urvey
e White I • I in my report of IN . th Annu<

THE SAGANAGA AND BASSWOOD AREAS. 363

ters of half an inch to three-quarters. In composition the rock varies con-
siderably. The prevailing dark element is hornblende, but this is locally
replaced by muscovite in moderate sized folia, but in places, near the
borders of the area, in very small scales. In one place, a mile within the
southern boundary, extensive generations of quartz occur, imbedded in a
feldspathic groundmass. The quartz, in places, is sericitic, and actually
passes into cuneately brecciated patches of sericitic material, only less
schistic than the sericitic beds of the Kewatin, to be described subsequently.
In this region the dark element is wanting. In other places this gneissoid
mass assumes the constitution and structure of a mica schist. In certain
regions the hornblende has degenerated to a chloritic state. This condition,
when present, is always found near the borders, and consequently, as we
shall see, in the higher portion of the crystalline mass. At one point, in
the southern part of the body of Saganaga lake, the formation seems to
consist of a chlorito-augitic groundmass, with a small quantity of light
feldspar and a greenish mineral disseminated.

This Area includes also Granite, West-Seagull, and Seagull lakes, and
the general character of the formation is everywhere preserved. The so-
called Giant's Range stretches a little north of east, and, passing Granite
lake, enters Canada. The Minnesota Survey has located its southern border
at sundry points, as far east as the middle of North lake. Beyond this I
have no personal knowledge of it, though incomplete information from the
Canadian Reports indicates its extension so as to include Dog lake, north of
Thunder bay, Lake Superior.

A remarkable feature of this gneissic mass, as far as examined by myself,
is the wide distribution of rounded pebbles, and their occasional aggregation
into truly conglomeratic formations. The significance of this will have to
be considered in another connection.

Throughout the whole extent of the Saganaga Area the rocky beds stand
nearly vertical and trend east-northeast, becoming more easterly in the
eastern prolongation.*

The Bassivood Area lies upon the national boundary, through ranges nine
to thirteen, or from Sucker lake to Iron lake — a sinuous line about forty
miles in length. From this boundary it extends northeastwardly into Canada
an unknown but rather limited distance. On the Minnesota side it has not
been completely explored, but has been traced southwestward well toward
Vermilion lake, while its western limit is still undetermined. It is known,
however, not to extend over fifty miles from the boundary. The beds of this
mass of gneissoid rock stand everywhere in a vertical position, so far as I

* The Saganaga Area has been more particularly described by me in the Sixteenth Annual Report
of the Minn. Surv., 1887, pp. 211-233, 292-209, 331-334.

:'."')1 A. WINCHELL — RESULTS OF \ l;« 1 1 1 : \ n" STUDIES.

have observed them, and they have a pretty uniform trend from northeast
to southwest. The mineral composition of the mass is similar to thai of the
masses jusl □ iticed, but the quartz element, while generally in abundance,
■ I >es not develop individuals over a quarter of an inch in diameter. The
orthoclase on weathered surfaces is predominantly red, and exteusive areas
"ii Crooked lake fairly glow in the distance with a bio >d-red hue. The in-
dividuals Borne times attain a diameter of half an inch- In other places the
feldspathic element ceases to be granular and becomes a groundmass in which
- imetimes grains of quartz are imbedded, but more frequently, in this con-
dition of the feldspar, the quartz is absent or nearly so. The ferro-magnesian
element is mostly black hornblende to the east of Crooked lake, but westward
this is generally replaced by biotite, with occasional muscovite. A.cross a
zone of a quarter of a mile along the boundary the dark mineral is chloritic,
with little quartz, and Btains the feldspathic groundmass. In this vicinity
occurs a condition consisting of hornblende, menaccanite, and feldspar.*

In a southwesterly direction the shores and islands of Burntside lake afford
striking examples of the nature of the formation and it- relation- to the
overlying crystalline schists, the bedded rock- retaining uniformly an attitude
nearly vertical. In this region hydromica gneiss frequently occurs, but
generally the dark mineral is either mica or born blend*

A small oval, granitoid Area lies immediately west of Vermilion lake.
including the West hay, and might be styled the Vermilion Area. Its
longer axis is directed about N. 65 E., and it- length is ab »ut twelve miles.
The breadth of this A.rea is sis miles. The rock is mostly a biotite gm
It- ,-t rike is not persistently northeast and southwest, but concentric with
the border of the Area, and the dip is outward from the centre on all Bides,
gradually approaching a horizontal position at the centre. This is a very
significant departure from thai close adherence to a northeast strike observed
in the ol her and larger area

From this region an expanse of mica schist extend- northwest aboul 50
milei Rainy lake, and this is followed by a belt of semi-crystalline Bchists
about live or sis miles wide, trending nearly N. 7> E. Beyond this we
find the Stanjikoming Arm of Lawson, inclosing all of the north-south arm
of Rainy lake,§ oblong in form, with it- longer axis N. 75 E., having a
length of 15 miles ami a width of '■'<-. The included area is occupied by
syenitic and biotitic gneisses with a border of crystalline schists and tb
remarkable included masses to which special reference will soon he made.

md Iron •■. pp.

III.

RurnUid< see I p. Minn, G 1800, |

injllcomln i, I 1 1 \ B

i , Report on th logy of the Rainy Lake I II.

AREAS ABOUT THE INTERNATIONAL BOUNDARY. 365

On all sides of this Area occur other and similar areas, encircled by belts of
crystalline schists and separated from each other, as in Minnesota, by vertical
synclinally folded troughs of semi-crystalline schists. The Area on the
south has just been mentioned as the Vermilion Area. Some of the others
have received from Dr. Lawson special names. The Sabaskong Area lies
northwest of this, separated from it by a belt of semi-crystalline schists about
three miles wide and stretching to the Lake of the Woods. This Area is
about 25 miles in diameter. Between the two areas, however, the small
Minomin Area, which is ten miles long and five miles broad, is crowded in-
Northwest of the Sabaskong Area lies the Obabikon Area, embracing the
whole of the Grand Presqu'ile of Lake of the Woods and Whitefish bay.*
It is 33 miles in greater diameter, N. 67° W., and 29 in the transverse direc-
tion. This Area, like the others, is girded by inclosing schists on all sides,
except perhaps a small break at the south. The belt of schists on the north-
west side attains a diameter of 20 miles. Within that breadth, however,
occur half a dozen exposures of granitoid rock, each encircled by schists
approaching a concentric strike. Beyond the bounding schistic belts are
other gneissoid regions stretching toward the northeast, north, and northwest
for distances not yet ascertained. From the Staujikoming Area toward the
east and northeast are other little exposed areas, while on the north is the
so-called Lake Harris Area. Between the Lake of the Woods and Thunder
bay, granitoid rocks are known to alternate several times with crystalline
and semi-crystalline schists, but the several areas have not been circum-
scribed by explorations.

Within each of the areas thus indicated the underlying rock is predomi-
nantly gneissoid. It is not everywhere equally foliated. If it anywhere
approaches the granitoid condition that is the part more remote from the
periphery. Within some of the larger areas we find two or more granitoid
centres, and around each of these the lines of gneissic foliation are concen-
trically arranged. Dr. Lawson states that in the Stanjikoming Area of
Rainy lake the more basic gneiss occupies, within the general Area, the belt
next contiguous to the environing crystalline schists ; the mere acid surrounds
the nuclear region. The former is a syenite gneiss with little or no quartz,
having a coarse texture and imperfect foliation. The more nuclear portion
is essentially a biotite gneiss of medium texture, very quartzose and distinctly
foliated.

Sporadic eruptions of granite occur, cutting sometimes the gneisses and
sometimes the crystalline and newer schists, but of these I have no occasion
to make particular mention at present.

*For the geology of the Lake of the Woods see Lawson, Geol. and Nat. ITist. Surv. of Canada, 1885
Report CC.

XLVIII— Bull. Geol. Soc. Am., Vol. 1,1889.

A.REAS l >F < !rY8T M.I.IM: SCHI8 PS.

Bach of the granitoid Areas (see fig. 1 I above mentioned ie flanked on all
sides by a belt of crystalline schists. These, by the Minnesota Survey, were
designated, in 1886, the Vermilion Series. A- a general formula they dip
away from the periphery of the Area, ami the angle of dip increases with
the distance until it becomes vertical (see fig. 7). In tin.- position they are
conformable \\ itli the newer Bemi-crystalline schists, \\ ith which they are now

in contact, and "ii the other side of which the crystalline BChists reappear in

vertical attitude, but soon leaning toward the next gneissoid mass. In the
region south of the Rainy river occurs a very extensive area of crystalline
BChists, but wide tracts of this arc horizontal or nearly so. [n crossing it
from north to Boutb we discern, first, a gradual diminution of northward
•lip: then an approach to horizontality, followed by a change to southward
dip, indicating the passage of an anticlinal. Further Bouth the southward
diji becomes vertical, and then a northward dip supervenes, Indicating the
passage of a synclinal. The northward dip continue- to contact with the
next gneissoid Area.* These undulations give opportunity to calculate the
thickness of the Vermilion series, ami give us a result in this place of 25,500
feet. Seldom, however, do they attain this volume. In fact, we find them
presenting all degrees of attenuation, down to complete disappearance. In
my computations I found them, in the interval between the Basswood and
White Iron granitoid Areas, possessing a maximum thickness of 2,1 L2 feet.
Around the Baganaga Area the crystalline Bchistsare little noticeable, while
on the Bouth Bide, iii .Minnesota, they may almost he pronounced wanting,
Farther east, however, in Canada, north of Gunflint and North lake-, the
south side of the Baganaga Ana i- found flanked by them. Observations

made in the last region Beem to Bh0W that the crystalline schists soinetiim -

disappear in (fit lim of strike, as if passing into gneiss.") A very remarkable

occurrence is recorded by the .Mi ssota Survey : on Disappointment lake,

.a-; of Snowbank, on the extreme northeastern border of the White Iron

granitoid Area. Here i.« the first marked deviation from an east- theast

Strike in all the distance from Tower, an interval of .... miles. The strike

in this region bends around to north-northwest Here a bornblendic mica
schist becomes conglomeratic with various kinds of crystalline rock- up to a

toot iii diameter. The howlders are mostly lenticular. After a change to a

nondescript rock, which has received the field designation of" muscovado,"

ilogy of the Little Fork, a tributary of Rainy river, I
,-i ifi.il> ii \ . w lochi \lh .1 ice /.' • .1/

nou ■ iiniiHi mil- in row Inferenoe 1* that thin Is the oentre of the gneisplc

i mentioned I It may be known a* the I I - / ■

i ompare with i . 3. Oi ml - observations, ■'

.11. \ . Winchell, pp, n • 119

ROCKS OF THE VERMILION SERIES. 367

the schist takes a great accession of feldspar and becomes a gneiss. This is
also conglomeratic, and in some places is almost entirely composed of bowlders.
The formation finally grows silicious and then diabasic, rising in ridges 150
feet above the lake. This varying conglomerate is two miles in width across
the strike.

The same observer has noted similar facts on the south shore of Rainy lake :

" In the southwest quarter of section 30, township 71-22, the mica schist is con-
glomeratic, containing innumerable flattened pebbles and bowlders, all changed into
rock very similar to the schist. * * * A little farther east the rock assumes the
appearance of a decided conglomerate, containing pebbles of granite, quartzite, and
schist as large as eight inches in diameter." *

Generally, however, the Vermilion series is represented by mica schists.
These are most frequently biotite schists, or biotite-muscovite schists, or bio-
tite-hornblende schists. Transitions from one to the other are of common
occurrence. Other characters of these schists are quite ordinary and do
uot require mention in a condensed sketch.

Structural Relations of the Granitoid, Gneissoid, and Schistoid

Rocks.

The phenomena observed under this head are extremely interesting. The
crystalline schists approach the gneisses under a steep inclination, very gen-
erally in Minnesota approximating to verticality. But we never observe an
abrupt junction between them. They are always in strict structural con-
formity. In thousands of observations on the nature of their approxima-
tion I have never seen an undoubted discordance of bedding. There are
no such facts in the Northwest as have been pictured in some of the text-
books. But all this is not adequate proof of the absence of a chronological
break. In fact, the reality of such a break is revealed in the phenomena
which I am about to describe.

In passing from the interior toward the periphery of one of the granitoid
areas we find portions of the neighboring schists included within the mass
of the gneiss. These increase in amount as we proceed. At an indetermi-
nate zone the volume of schist equals that of the gneiss. Then we encounter
fragments of the gneiss included in the schist. The schist, meantime, be-
comes extremely cut by ramifying sheets of gneiss, granite, or granulite
proceeding from the centre. Sometimes a very intricate net-work results.
At remoter points these ramifications diminish and the schist finally presents
itself in its normal and usual condition.

The portions of schist are generally angular and flattened. They are evi-
dently fragments of schistic sheets separated from the body of the schists

* Sixteenth Minn. Rep., p. 416. Such expressions as 71-72, above, refer to township and range.

A.- WTNCHELL — RES! LTS OF AJH III AN STUDIES.

and moved certain distances into the body of the gneiss. We find them of
all sizes and of various thicknesses. At the points remotest from the schist
body the fragments may be a foot or three feet in Length, as presented edgewise
at the usual outcrop. At positions nearer the schist body the fragments are
larger, but generally without increased thickness. They become large flat
tables turned on edge, with thickness sometimes reduced to two or three
inches. Sometimes we find them broken and the pieces separated a few
inches. Next, we find their dimensions extending beyond the limits of prac-
ticable observation. They appear like split-off beds of the schists. In this
Btate their thickness diminishes, in many cases, to an inch or half an inch
or even a quarter of an inch. Thus we are compelled to contemplate the
mixed formation as a unit, produced by a system of alternating or inter-
rupted activities.* These included fragments retain, generally, a surprising
parallelism with the bedding of the body of schists. Even the short frag-
ments most remote from the schists generally lie in a conformable position.
The nearer sheets retain a rigid parallelism with the bedding of the body of
schists, and this is always coincident with the foliation of the gneiss, when
it e.\i-t-. The force which separated the schistic sheets could not have been
violent. The breakages which occurred could not have resulted from any
eruptive action. There may have been evenly distributed pressures, and
these may have floated apart the co-adapted fragments which were parted
by some adequate force. But they were not generally floated out of a com-
mon plane. The evidences of violent action are wanting.

Exhibitions of phenomena such as above described are witnessed on every
band, but none surpass those found on the islands in Burntside lake. Re-
markable examples are see i White Iron lake. 1 The State Geologist of

Minnesota remarks as follows of an occurrence on the Vermilion granitoid

Area, at the western extremity of Vermilion lake:

"Following the mica-schist bluffs west wardly, noting tin' line, conformable, and
increasing number of their sheets of granite, the facl suddenly flashes on the observer

that the rock has 1> me changed ten reddish-gray gneiss, and n moment's further

examination only i- net show it- further conformable transition to granite, thus

making a conformable passage from en.- extreme to the other."

Of another locality in the vicinity lie say-:

"Showing tli" -Mm" kin. I of conformable interstratiflcation downward, demonstrat-
ing the existent I'u large mass of granite [gneiss] conformably interst ratified in

mica schist and graduating into mica -<-lii-t above and below.'

Of the junction of the gneiss and schisl at Whitefish bay of the Lake of

tin- \V 1-, I >r. Lawson saj

l in- junction it-"lf i- "\| 1 on tlii- shore, on il>" fi f a lew dill' presenting

the appearance figured in the annexed diagram, there being apparently no sharply

ill: .1-1.

ALTERNATIONS OE GNEISS AND SCHIST. 369

defined line of contact, but a transitional series of layers of alternate gneiss and schist.
These bed-like sheets of gneiss within the schist, however, are injected." *

Again, speaking of the same subject in a later report, Dr. Lavvson, refer-
ring to these sheets, says :

" Some are acres in extent and some take the form of bands one or several miles in
length by hundreds of feet in breadth, which in single sections might easily be mis-
taken for interstratifications with the gneiss." f

I introduce here also a remarkable record made by Dr. Lawson concern-
ing another occurrence in the region of the Lake of the Woods :

"The interesting or prominent portion of the point is occupied by the following
alternation of bands of gneiss and schist, the strike of the rocks being S. 50° E. and
the dip either vertical or at very high angles to the south :

1. Gneiss 1 foot 7 inches.

"J. Hornblende schist 54 feet.

3. Gneiss 11 "

4. Hornblende schist 60 "

5. Gneiss .3 " 8 "

6. Hornblende schist 31 "

7. Gneiss 1 " 8 "

8. Hornblende schist 11 "

9. Gneiss 20 "

10. Hornblende schist 22 "

11. Gneiss 0 " 8 "

12. Hornblende schist 58 "

13. Gneiss 4 " 4 "

14. Hornblende schist 6 "

15. Gneiss 0 " 6 "

16. Hornblende schist 32 "

17. Gneiss 12 " 2 "

18. Hornblende schist 13 "

19. Gneiss 1 " 8 "

20. Hornblende schist 4 "

21. Gneiss 3 "

22. Hornblende schist 1 " 3 "

23. Gneiss 1 " 6 "

24. Hornblende schist 5 "

25. Gneiss 0 " 4 "

:'ii. Hornblende schist 0 " 8 "

27. Gneiss 1 "

28. Hornblende schist 1 "

29. Gneiss 2 " 8 "

30. Hornblende schist 5 "

31. Gneiss 100 ;<

32. Hornblende schist 12 "

33. Mixed gneiss and schist 20 "

Gneiss, indefinite thickness. "j

* Geolog. Report Canada, 1885, Doc. CO, pp. 72, 1i. See also Rep. 1888, F, pp. 116, 118, et pas.

f Report, 1888. p. 132.

%Ann. Rep. Gcol. Surv. Canada, 1885, Doc. CC, pp. 74-75.

370

\. WINCHELL — RESULTS OF A.RCHEAN STUDIES.

Dr. Lawson remarks: "These bands of gneiss altercating with the schist
are for the mosl part regular and bed-like in their characters, but their true
nature as iujected Bheets or dikes is sufficiently revealed."

It will he tinted in the above table that the thickness of the schist beds
gradually diminishes from top to bottom, while that of the gneiss beds grad-
ually increases. This denotes advance from the gneissic side toward the
schistic.

Whether these numerous and tenuous gneissic hands present the verisimili-
tude of " injected sheets or dikes" may be better decided after noting a
state of facts which has fallen under my own observation. On the north of
Guntlint lake a traverse was made northward from the Animikie slates to
the Saganaga gneissoid area. As usual a belt of crystalline schists was

\la

*.'!

•- i

•'•

J c

1 •

" '•

i si 2. — Relation

crossed, though it did not exceed three hundred feel in breadth. This was
made ii | > of alternation- of rigidly parallel ami indefinitely extended bands
of uralitic schisl and a gneissoid rock. These became, in one pari of the
belt, so slender that I estimated thai five hundred alternations occurred

within the -pare of fifty feet. This would give Inn an inch and tWO-tenths

for the mean thickness of each. Bui many of them were thicker than this,
while many others wen- attenuated to a thickness of half or a quarter of an
inch. And \ei each preserved a rigid continuity of direction.
The structural relatione of the granitoid, gneissoid, and Bchistoid rocks

i/ , pi

RELATIONS OF SCHIST AND GRANITE.

371

present also a phase somewhat different from that which we have been con-
templating. In a multitude of cases the schistic fragments are separated by
an irregular fracture from the parent mass, and, though their original align-
ment with its bedding planes is not impaired, it becomes evident that the
intervening gneiss is not strictly an interbedded sheet. See fig. 2.*

In other cases the schist is more thoroughly disrupted, and the gneiss
loses its foliation and assumes a distinctly granitoid character. It insinuates

32 ^12 it.

Figure 3. — Relations of Muscovite Schist and Granite, Burntside Lake.

itself into narrow fissures aud begins to cut the schists in many directions,
presenting the aspect of true granitic veins. See fig. 3.f

In the regions marked m the schist and granite are intimately mixed.

*See also fi&r. 33, Fifteenth Ann Rep. Minn., p. 290; and fig. 14, " Relations of crystalline rocks at
Pelican Lake," Sixteenth Ann. Rep. Minn., p. 451.

tSee further fig. 30, Fifteenth Ann. Rep. Minn., p. 78; fig. 53, Sixteenth Ann. Rep. Minn., p. 295; and
fig. 12, Sixteenth Ann. Rep. Minn., p. 447.

• ■ I _

A. WINCH ELL — RESULTS OF ARCHEAK STUDIES.

Speaking of the south shore of Rainy lake, Mr. II. V. Winchell remarks:

" The schists lie against the gneiss along the coast. They are mixed undent and

twisted up together in a remarkable fashion. Long feelers of the gneiss or granite

stretch off through and across the beds of schist, and from them branch out smaller,

winding, twisting veins in all directions

We discover evidences of interactions jstill more energetic. In numerous
cases we have observed fragments of gneiss or syenite inclosed in the body

Kp.i i.i i 1' id Wai ■*' Rapids on tl Lake.

• if the Bchists. Bee fig. \.'< The dark bands represenl schists; the li;_rlii
spaces between, g g 7, air gneiss; detached and included masses are Been

:il < '< < i one with vein-.

A curious instance is found on Rainy lake:

• There ii Buch :i mixture in ill" rocks that beds of any considerable length are nol
(■• I"- -••■■ii M liases round, Bquare, oblong, irregular, thin, thick, and In tact all shapes

ii i

■ fig II, ! tod lit?. I '/ . ] :

GRANITIC MASSES ENCLOSED IX GNEISS.

373

and sizes, of mica schist are seen in the gneiss where the gneiss predominates, and of
gneiss in the schist where the schist is the main rock.' *

In some instances a mass of syenite inclosed in schist holds in itself
fragments of schist, as in fig. 5. In many cases also the schistic beds wrap

Figure 5. — Schist inclosing Granulite, itself embodying .1/"-" schist, Burntside I

around the gneissic fragmeuts, indicating that the fragments were introduced
while the schist was in course of formation ; and indicating, too, that the
gneiss had been already consolidated when the schist was forming (see fig.
tip. In very many (if these cases the gneissoid fragment has been bent in

Figure S. -Bydromiea Schist wrapped around Masses of Granite, Farm Lake, Minn.

a marked degree and shaped to the enwrapping schist. This seems to show
that the consolidated gneiss had been rendered plastic again.

Sometimes the schists appear intertwisted without the presence of gneissic
fragments.^ Sometimes the included fragments are quartzitic, and the
mutual actions are the same.§ These phenomena indicate some relative

* H. V. Winchell, Sixteenth Mian. Rep., p. 428.

t-See further illustrations, fig. 36, Fifteenth Ann. Rep. Minn., p. 89 ; Ibid., fig. 38, p. 97.
This ia illustrated in figs. 4u and 42, Fifteenth Ann. Report Minn., pp. ill and 116.

\ Si,,/,, nth Minnesota Report, p. 409.

XLIX— Bin,. Gf.oi. Soc. A.m., Vol. 1, 1889.

3*i 1 A. WINCHELL — RESULTS OF ARCHEAN STUDIES.

movements of the t \\ < > masses of rock material. But there is no evidence
of any other than very slow and gentle movements. It would appear that
the plasticity evident in the included gneissoid fragments extended, also, to
the schist, though in a less degree. Nothing appears to prove whether the
gneissoid fragments were introduced during the sedimentary deposition of
the pre-schistic heds — the layers of soft sediments adapting themselves to
the introduced masses; or were thrust into the body of schist after consoli-
dation and re-softening — the layers of schist adjusting themselves to the
foreign bodies. There are, however, no traces of lines of travel through
the schists, indicating that the fragments had reached their position through
some passage opened from the place of entrance into the schists. Their
environment is as uninterrupted and close as if the fragments had been
original enclosures.

Phenomena of the class cited above have not been very widely recorded.
But they are not unknown. Dufreuoy and Elie de Beaumont have de-
scribed the massif of central France as composed almost entirely of granite
and gneiss, the " latter passing up into mica schists and downward into fine-
grained granite, with which it alternates."* Alternations of granites and
gneisses have also been described from America f and other countries. M.
A. Michel-Levy, in discussing the crystalline rocks, speaks of these inter-
beddings as somewhat familiar-!

MlM.KALOGICAL RELATIONS OK THE GRANITOID, GNEISSOID, AND S< HIST-
OID Rocks.

Throughout the Northwest it is difficult to distinguish recognized gneiss
from recognized schists of the mica and hornblende bearing sorts by any
mineralogical character except its larger percentage of feldspar.§ It is true
that the gneisses are generally coarser and heavier bedded, but they are not
always so. It is true that the schists occupy on the whole a different hori-
zon ; but I find them frequently in the same horizon. When I examine
closely the characters of the constituent minerals I find nothing about the
quartz, nor the micas and hornblendes, nor the feldspars by which I can say
that a given character belongs rather to the gneisses or to the schists. ||

I. de la France, vol. 1, 1841, p. 109; Prestwioh, G f ol. i, 1886, p. 421.

e, for Instance, Ring, I'm tieth Pi , vol. i, 1878, p. 102.

ttione in tin- acidic gneisses, he Bays: " Ces Intercalations sont touj "8

parnli' ilea ;> in Bchistositd. * * * Lea gneiss acides >-\ '!<• plus en pin* oristallins dominent :i In
jpiii.s il>- admettenl des Intercalations frequentes de micaschistes •■( de leptynites, auquels
• Hi 'i.- nombreui dellts d'amphibole ••' de clpolin.'

Bull, di '•■ gePlog. 'I'- Frai _ Nov., i>s7. p. 103.

facl tin- i ii Doted of other regions. King Bays: "The crystalline Bchists and gneisses

formed of Identically tl mhydroufl minerals which characterize the granites. * * *

me minerals, and, furthermore, theii copical Btruoture and i he

character of their foreign inclusions are identical." King, Fortieth . ol. i, 1878, pp,

117 i

This is meant rather for a provisional than a final statement M, \ Michel-L6vy has enumei
microscopic character! by which be thinks the crystalline •-'•lii-i- differ Irom the gneia
106.

BLENDING OF MINERALOGICAL CHARACTARS. 375

Furthermore, the facts which I have cited in reference to the interbedding
of gneisses and schists show that, while each stratum retains a characteristic
individuality, this is something which depends, first, upon relative richness
in feldspar, and, second, upon the coloration and relative proportions of the
other two essential constituents. The very facts of the geologically rapid
alternation of gneiss and schists argues the persistence of the same petrogenic
forces and their indifference to the relative proportions of feldspathic ele-
ments. It is easy to believe, however, that some change in addition to that
of the supply of material takes place when the formation becomes schistic,
and that an seonic change may be conceived as inaugurating the formation of
the great body of the crystalline schists ; but, as I am here dealing only
with observed facts, I repeat, no mineralogical alternations are found in the
zone of lithological alternations except the changes in the proportions of
feldspar.

The indifference of Nature to a greater or less proportion of feldspar is
indicated by the fact observed in some cases that in the local passage from
the schistoid to the gneissoid phase the schistoid aspect melts into the
gneissoid, and the resulting rock is simply the product of their interblend-
ing.

The facts stated in these paragraphs have been with me the subject of
common observation ; but the conclusion which I base on them is decidedly
in conflict with prevailing opinion ; and I shall make a few citations from
the recorded observations of ofher geologists upon similar rocks. At a
certain locality on the Little Fork river, Mr. H. V. Winchell describes the
situation as follows :

"Just below, around the point, is an outcrop of mica schist interbedded with thin
beds of gneiss. * * * It [the schist] is quite thin bedded and is the characteristic
rock of this whole region. In places it is hard to say which is schist and which is
gneiss or where one bed stops and the other commences, and, again, they are separated
quite distinctly.'1 *

Speaking of a locality on the south shore of Rainy lake, the same observer
says:

"In the southwest quarter of section 25, in the same township [71-23], this diabase
has all graduated into a rock that is very plainly gneiss, and, going a little farther
south across the strike, it is still farther changed into a thin-bedded gneiss and finally
into mica schist with the ordinary strike and dip." f

Of the occurrence at another point on Rainy lake the same authority
reports :

" At this place is a bed of gneiss that cuts across the schist for some distance, then
comes into conformity with it, and all at once splits up into thin beds an inch or two
thick and becomes lost in the schist." J

* Sixteenth Ann. Rep. Minn. Surv., pp. 405-6.
t Ibid., p. 415.
% Ibid., p. 419.

376 A. WTNCHELL — RESULTS "l A.RCHEAN STUDIES.

Similarly, Dr. Lawson observi -

■ In some of these lenses the interfusion of matrix and inclusion has been so com-
plete that they are entirely made up of this transitional rock, which has the facies of
b syenite

Describing the rocks of the Lake of the Woods, he says

•• It is >i"t uncommon to And in these mica schists a small proportion of feldspar,
which gives them the character of finely laminated gneisses, in pla<

Referring to the north shore of Vermilion lake, State Geologist X. H.
Winchell saj - :

"This schist has a very evident sedimentary structure. It i- firm and even shows
an approximation to gneiss, the foliation of which is then the same as the bedding
structure <>t' the schist. When, however, the gneissic structure comes on, the grains
arc finer than in the schist, the color is darker, but the striping due t<> sedimentation

i- -till preserved.

I quote again from Dr. Lawson :

•■ < >n the Bouth shore of Rainy lake, near « 'outchiching rapids, there i< in association
with the mica Bchists an iron-gray micaceous gneiss, differing from the former only in
tne possession "fa feldspathic constituent. It might, perhaps, he rather called a feld-

spatbic mica schist than a L;'nei--

"The rocks of the Rice Hay Area [Rainy lake] of the Coutchiching series [mica
schists] differ somewhat from those of the same series farther Bouth. They are. as
before, all very quartzose and fall into two varieties, those containing feldspar and
those free from it. * * * En the feldspathic variety * * * the rock assumes
the form of a gneiss of peculiar character. * * In the-.- trthoclase occurs

sometimes in large crystals from half to an inch aero--. * * There i- a con-

siderable proportion of feldspar associated with the quartz throughout tin' rock. The
schists or gneisses, in which the augen-like feldspars were observed, are is proximity
to the very coarse mica-syenite or syenite gneiss on the south side of Bopkins bay,
which appears to be of irruptive origin. "2

This same rock, so gneiss-like thai Dr. Lawson scarcely know- whether to
call it gneiss or schist, is described on the following page a- "an eminently
granulitic aggregate. The granulitic or roundel character of the

grains i-, however, characteristic only of the quartz and orthoclase, while the
plagioclase often presents irregular or granular shapes."

From an island in Rainy river he describes a rock which " has tin- aspect
..I' a very fine-grained gray Lrnei-> of even lamination. but is found

to be made up wholly of quartz with a little plagioclase. The

rounded Bhape of the constituent grains of quartz appears to he due to water-
wearing action in an original .-an<l.'"j

Ibid., p. He,

Ibid , i' 1 1 1 1 ' lorn pel ■■ duo pp UO i > ■

ESSENTIAL UNITY OF GNEISSES AND SCHISTS. 37 I

It seems to me that the facts here cited, with a great multitude of others
of similar tenor, render it necessary to unite thegueissoid and schistoid rocks
under one petrographic mode of derivation. They are so inseparable on
any fundamental grouuds and are so blended together, both structurally and
mineralogically, that no reasons appear to exist for a reference of one class
to a mode of orip-iu fundamentally different from the mode of origin of the
other class. On this question, however, I only propose at present to cite
some observed facts. The interpretation of them may be subsequently under-
taken.

Areas of Semi-Crystalline Schists.*

The crystalline schists are succeded by a system of semi-crystalline schists.
They range, however, from fragmental crystalline to earthy. They succeed
in perfect structural conformity with the older schists, with only slight
indications of stratigraphic disturbance. Their attitude is generally verti-
cal or steeply inclined. Their position is between and surrounding the
gneissoid areas. In northeastern Minnesota their position is between the elon-
gated Basswood Area on the north and the elongated White Iron Area on
the south. The belt, therefore, holds a persistent strike for seventy miles.
In this region it is not revealed as an encircling belt, because the southern
half of the White Iron Area is covered by gabbro and the northern border
of the Basswood Area remains uninvestigated; but theSaganaga Area is
bordered on the northwest, west, and south by these schists, and the belt
passing on the south side has been traced along the north side of Gunflint
aud North lakes and has been identified as far east as South Fowl lake, in
the third range of townships east of the Minnesota meridian, twelve miles
west of Graud Portage. In the Vermilion Granitoid Area, however, the
strike of the semi-crystalline schists is circumferential. On all the sides the
dip is steep and it diminishes from all directions toward the centre. This
is the arrangement of these schists around the borders of the numerous
granitoid areas occurring in the region of Rainy lake and Lake of the
Woods.

In each of the intervals between neighboring granitoid areas the semi-
crystalline schists present the structure of a simple synclinal fold. This is
close-pressed along the axis, and the strata are accordingly vertical. Pro-
ceeding toward the centre of the granitoid area, the dip in the majority of
cases being always toward the synclinal, becomes less steep. The granitoid

* These, with the crystalline schists included, were named " Keewatin series " by Dr. A. C. Law -
son in his report of 1886, pp. 10-15. Subsequently he separated the crystalline schists under the
name " Coutchiching series'' (.1//.. r. Jour. Sei., 3d Ser., vol. 32. 18S0, p. 477.) The name Keewatin
has been employed by the Minnesota Survey in the sense thus restricted, but the term " Vermilion
series " was already in vogue before Dr. Lawson's separation of the crystalline schists. As the
spelling of Chippewa names can scarcely be regarded as fixed by any literary or scientific authority,
unless it be the usage of ethnographers, I suggest that the useless second "e " be dropped from the
name employed by Lawson. thus making it " Keuatin " (pronounced Ke- way-tin). An orthography
better supported by linguistic ethnology would be Ki-we-tin.

• >.

A. WINCHELL — RESULTS OF A.RCHEAN STUDIES.

area, therefore, is essentially dome-shaped, and the crystalline and semi-
crystalline schists appear to have once extended over the dome and to have
been subsequently denuded fig. 7 i. In some cases the proximate vertically
of tin' structure persists i<> tin- middle of the granitoid ana ami quite across
ii. We must, nevertheless, conceive the middle of the area as tin' position
of an anticlinal axis or point.

... o

w 3

a o

5 £

^ o

■ 2

: o

IS
t..

z
O *

z </>

a. \
O .

• ' ••• ■ •

Fioueb 7. — Plan of the Folding of the Orystalline and Semi-Cfrystalliru Roeki ■ "■ Wo thv

■casionally the single synclinal becomes two or perhaps three with partial anticlinal* inter-
calate'!.

It will be inferred from the structure described that a traverse from side
t i Bide of the semi-crystalline zone exposes the members of the series in di-
rect and then in inverted order and gives twice its total thickness. Simi-
larly a traverse across the area of crystalline schist- and gneisses presents
the succession in direct and inverted order and gives twice the exposed thick-
of those terranes.

The Lithologk \i. ( Ionstiti riOM of the System of Semi-( Irystalline

Schists.

The lithology of this system is obscure, anomalous, multifarious, and w ith-
• >ui parallel in any other part of the earth's crust. It is essentially a system
of bedded rocks, bul they are cul by numerous basic eruptives. The beds
are mostly clastic, bul in place- they present the aspect of decayed diabasic
sheets. Certain beds unequivocally fragmental in one locality pass along

nnii of theae Bchl • l In my Report of observations for 1886

i ii' l also by Dr. Lawaon Id tils Report on the Lake of the w I*

in iK8tj iji. \"~. Bin he ••••in- to detect evidences, In some Quaes, "i two or three synclinal* in the
width ••! tli" belt. I his

• >f i • iti ucture

- may • io without any ohange in oar conception "f the mechanics

INTERGRADUATTON OF VARIOUS ROCKS. 379

the strike to beds petrosiliceous, felsitic, and pseudo-diabasic. A tei*rane
bearing the characters of an argillite passes in one direction into a siliceous
schist and in another acquires felsitic or serpentinous matter until it arrives
at the stage of a petrographic nondescript, which I have called " porphyrel-
lite," but which approaches somewhat to Hunt's " parophite." The same
terrane passes on one side into an obscure conglomerate and on the other
into a porphyroid condition, sometimes with pebbles added. In this system
are formations which may be styled volcanic tuffs, often light colored, with
imbedded angular fragments blending with the groundmass, often agglom-
erate and nondescript.

It is evidently beyond the scope of this paper to furnish an elaborate ac-
count of these rocks, but I will endeavor to enumerate their leading strati-
graphic aspects.

Argillite is one of the most persistent terranes. Its centre of characteristic
development in the trough between the Basswood and White Iron granitoid
areas is in the region of Moose and Newfound lakes, in the ninth range of
townships west of the Minnesota meridian. It is here prevailingly russet,
handsomely cleavable in immense vertical sheets, and strictly argillitic. In
places, both eastward and westward, it assumes a slaty color. On Ensign
lake, to the northeast it, becomes sericitic, and the same variation is wide-spread
westward, about Eagle-nest lakes. In both directions it sometimes takes a
greenish, chloritic-sericitic character. As far west as Tower it becomes
rather characteristically a sericitic schist, and it is in this that the great de-
posits of haBinatite occur. At a few localities on Ensign lake the soft sericitic
argillite contains a great abundance of quartz grains, and this character reap-
pears 18 miles father northeast, on Frog-rock and Town-line lakes. The same
feature is widely distributed in the vicinity of Vermilion lake.* North and
northeast of Ensign lake, on Sucker lake, and at the west end of Knife lake
it becomes siliceous and in places is simply a black siliceous or flinty schist,
here as everywhere standing on edge. In the more exact direction of the
strike it continues to Ogishke-muncie lake and along both shores of this lake ;
and throughout the vicinity this argillite undergoes a remarkable modifica-
cation by the inclosure of long-extended series of pebbles and bowlders, form-
ing what' we know as the Ogishke conglomerate/^ It is to be remarked in
this case that the slaty beds do not curve around the bowlders. On the north
and west of the lake the matrix of the conglomerate preserves well its slaty
character, but on the south it has been altered to a silico-diabasic aspect.
In this state the pebbles are inconspicuous, but they may be distinctly seen
on smoothed surfaces under water. This condition also exists on Crab lake
and the northwest part of Frog-rock lake. The bowlders and pebbles of

* Fifteenth Minn. Rep., p. 20.

t'fhis conglomerate, in the judgment of my brother, is embraced in the Animike formation.
Fifteenth Minnesota Rep., pp. 01, 97; SeventeentltRep., pp. 17,47- My views and reasonings are given
in' the Sixteenth Rep., pp. 344-350, 259-360.

380 A. WINCHELL — RESULTS OF A.RCHEAN STUDIES.

this conglomerate are derived from crystalline rocks, being largely granu-
litic, gneissic, and quartzose, and they lie imbedded bo firmly that fractures
of the rock pass equally through them and the matrix. This matrix gen-
erally is a g 1. but often Biliceous, argillite, dark, or inclining to greenish,

with cleavage coincident with tin- sedimentary bedding

No other occurrence of the < tgishke conglomerate is at present known in
Minnesota, but Dr. Lawson has Bhowa that it recurs on Rainy lake, at Ral
Rool bay, and also on Grassy and Shoal lakes,* where similar pebbles are
imbedded in a fissile, glossy, green, chloritic schist. Seventy-live miles north-
east oft >gishke-muncie lake, in the vicinity ofThunder hay on Lake Superior,

cur vertically-standing conglomerates of exceedingly similar character.
I quote from the Report of Sir William E. Logan:

"Rising in the series [superjacent to the gneisses] the dark-green slates become
interst ratified with layers holding a sufficient number of pebbles of different kinds
to .•.institute conglomerates. The pebbles appear to be all derived from altered rocks.
They vary greatly in size in different places and occasionally measure a t'""t in

diameter. Where the slate conglomerates have I n worn by the action of water, the

pebbles are generally worn down equally with the rest of the surface, and, though a
very distinct picture of them is presented on Buch a surface, * * * it yet often
happens, unless the pebbles are of white 'mart/,, that they are very obscurely dis-
tinguishable on fracturing the reek, both the pebbles and the matrix having a gray
. showing very little apparent difference in mineral character. * * The

mck has nowhere on the lake hern observed to display true slaty cleavage independent
of the bedding." f

These are characters of the ( )^ishke conglomerate. The only difference

is a re greenish color of the slates. The same conglomerate is exposed at

other points on the shore of Lake Superior. A voluminous outcrop is noted
at the month of the River Don', where seventeen hundred feet are described
as green slate rock in vertical attitude, striking ea-t and west and presenting
sometimes ribboned edges of green, black, red. and -ray and mostly charged
with crystalline pebbles and bowlders firmly imbedded. "Toward thelower
part it assumes more the character of the gneiss which usually succeeds it."

In the region of Pog lake, north of Thunder hay, the slate- which else-
where are greenish and conglomeratic are described as "dark greenish blue
or greenish Mack slate-, passing downward almost imperceptibly into a horn-
blendic gneiss.

I direct particular attention to this east ward extension of dark and green-
ish Blates, di H-' ly conglomeratic, at intervals, as far as the eastern shore of
Lake Superior.

i
o

186 '•. pp ' l

PORODITE, PORPHYRELLITE, ETC. 381

Altered Tuff's and Mixed Rocks. — Though the argillites and their included
conglomerates are the most bulky -and conspicuous member of the semi-
crystalline schists, they are not the most characteristic feature of this sys_
tern. Immediately eastward from Tower the proper argillites have a feeble
development, and they seem to be partially replaced by sericitic and chlo-
rictic argillites and sericitic schists, and the same conditions are found at
many places eastward as far as Ogishke-munice. But in the vicinity of
Vermilion lake certain clastic rocks represent very imperfectly the character
of sericitic schists. The transition from these to true schists is, many times,
along the line of strike, but it is also sometimes across the strike. These
nondescript rocks, when well developed, have often been designated
" porodite " by the Minnesota Survey. They are generally ashen colored,
mostly fine textured, generally rather soft, but with disseminated quartz
grains, which sometimes attain dimensions of a quarter of an inch, and they
show obscure tracings on weathered surfaces, suggesting an original conglom
eratic or agglomeratic constitution. They have only very obscure lami-
nation. Beds answering such a description are extensively iuterstratified
with characteristic schists. There are also occasional beds of this character
which cut, dike-like, at a small angle across the strike of the graywackes.
These probably, though similiar, have had a different origin. It seems to
be a rock allied to this porodite, which in places contains small quartzose
and granitic pebbles, and constitutes the "Stuntz conglomerate," which, but
for other evidence, might be regarded as occupying the horizon of the
Ogishke conglomerate.

Porphyrellite. — The porodite of Vermilion lake holds lumps of serpentine,
and the recognized sericitic and chloritic schists are sometimes serpentinous.
These appearances increase eastward. It does not appear that the magnesian
formation is developed at the expense of the argillitic, though it is certain
that the magnesian character is sometimes superinduced on an argillitic
foundation. At Sucker lake, on the boundary, certain schists having a ser-
pentinous aspect begin to abound. This is in a zone somewhat north of the
argillites and nearer the granitoid rocks of the Basswood area, and there-
fore regarded as underlying. At Sucker lake these rocks possess a greenish,
argillitic aspect, but their edges transmit light, and the hardness and feel
are slightly magnesian. Traced to the eastern ramifications of Knife lake,
tliis formation attains an imposing development. It may, under some of its
aspects, answer to the " parophite " of Hunt, but I have called it, for the
purposes of description, " porphyrellite." The formation is unquestionably
bedded, but it is often imperfectly so, and it is intersected by a multitude
of irregular local fissures making acute angles with the bedding and with
each other and converting the rock sometimes into an infinite number of
small cuueate and lenticular forms closely packed together.

L— Bum.. Geol. Soc. Am.. Vot,. 1, 1889.

382 A. WINCHELL — RESULTS OF Ai:< '11 KAN STUDIES.

This remarkable and important formation presents graduations in many
directions from the typical state, but the scope of this paper permits do more
than a mere enumeration : 1. [t graduates into Blate-colored argillite, both
along the strike and across it. 2. It often develops whitish, obscurely out-
lined crystals of feldspar. These are found in all stages of development from
incipient visibility onward. This condition I have called " porphyrel." •">.
The formation sometimes contains distinctly outlined, rounded pebbles,
especially on the remote anus of Knife lake. The pebbles are sometimes
present with the porphyritic structure. 4. The formation also, at times, de-
velops grains of quartz, and on the north of < lunflint lake both quartz and
feldspar. 5. It graduates into the green schists, which possess exactly the
same structure and aspect with a greenish color and diminished translucency.
These are the " Kawasachong" or " Kawishiwin " rock, by some regarded as
a decayed diabasic rock. ti. It graduates into a gray wackenitic rock with
tine granular quartz and feldspar in an argillaceous base. 7. The gray-
wackenitic rock assumes a larger proportion of silica and becomes something
like hornfels. <s. The formation acquires felsitic matter and becomes agood
felsitic schist, and this is quite extensively developed. !•. Through this
stage it passes into a silico-diabasic slate, a protean formation truly of
which Still much remains to be learned. The essential ingredient is widely dis-
seminated in this system of rocks and can often he detected in gneisses and
other petrographic conditions not otherwise affiliated with porphyrellite.
Thus disseminated I have called it " Kewatin stuff."

Chraywacke. — As nearly as 1 can judge, very little typical graywacke exists
in this Bystem of rocks, hut the name has been much U8< d, and the condition
to which it i> applied approximates conformity to the accepted definition. It
IS composed of .-mall water-worn grains of quartz and feldspar, imbedded in

an argillaceous groundmass, with minute mica scales and particles of a black
BUb8tance, and generally some silica chemically combined : hut from this
Mate i- passes into a siliceous hornfels and a quasi-diabasic state, and, on the

other hand, graduates into a massive argillitic rock.

'fie- graywacke holds position next to the crystalline schi-ts, hut it is not

everywhere present in its place. Next to the gray wacke, as nearly as J have
ascertained, come- the poroditic and porphyrellitic formation, with its
numerous phases. Next bigher in the scries occur the argillites, with their
beteromorphs, and thesericitic Bchists, while near the centre of the folded
synclinal occur the beds of haematite. In a tentative way, therefore, I would
arrange the members of the system of semi-crystalline rock- in the following
manner i

I. Bericitic Bchists inclosing beds of hsematite.

.;. Argillites and tin- include. 1 Ogishke-rauncie conglomerate, with len-
ticular masses of dolomite.

SUCCESSION OF THE SEMI-CRYSTALLINE ROCKS. 383

2. Porphyrellite and chloritic schists and other conditions into which they
graduate ; also the porodites, agglomerates, and tuffs of nondescript character.

1. Graywackes.

(Underlain by hornblende and mica schists.)

In his description of the corresponding system of rocks on the shores of
the Lake of the Woods Dr. Lawson groups them as follows :

" Felsitic, serieitic, and other glossy fissile schists of a hydromicaceous or chloritic
character, with some carbonaceous schists and limited occurrences of limestone.

'•Mica or hydromica schists, clay-slates, and quartzites.

" Hornblende schists, with associated trap rocks, principally altered diabases and
diorites." [Afterward excluded from the Kewatin.] *

In the vicinity of Rainy lake he gives :

" Felsitic schists (quartz porphyries and their tuffs) and agglomerates.
" Altered traps and green hornblendic schists." f

Dr. Lawson's hydromica schists are my serieitic schists. His agglomerates
are embraced in my No. 2, and so, I think, are some of his felsitic schists.
While the general character of the rocks studied by him is plainly the same
as that of the rocks described by the Minnesota Survey, the correlations in
detail have not yet been completed.

The approximate thickness of this system of rocks in Minnesota, as deduced
from four sections between the Basswood and White Iron Areas, is about
15,000 feet. In the Rainy lake region Dr. Lawson has calculated thick-
nesses of 10,200 and 13,200 feet.

Structural and Mineralogical Relations of the Crystalline

and Semi-Crystalline Schists.

Wherever the crystalline and semi-crystalline schists are seen in juxtaposi-
tion their stratification is strictly conformable. Wherever the crystalline
schists are wanting, the semi-crystalline schists are found in conformity with
the gneisses. Moreover, whether the semi-crystalline schists occur in jux-
taposition with the crystalline schists or the gneisses, there exist frequently
those transitions by alternation which characterize the passage from the
crystalline schists to the gneisses. This mode of transition, however, is much
the most characteristic of the passage from the semi-crystallines to the crys-
tallines ; but this passage is simultaneous with mineralological changes which
must also be mentioned.

It was early remarked that the Minnesota graywackes contain always
some proportion of fine mica scales. As we descend to the neighborhood of

* Canadian Geological Report, Doc. CC, 1886, pp. 12, 29, 106, etc.
t Canadian Report, 1888, Doc. F, p. 46.

384 A. VVINC'HELL — RESULTS O] LRUHEAN STUDIES.

the mica and hornblende schists the proportion of mica scales generally
increases, and in some states the graywacke has much the aspecl of a fine,
earthy mica Bchist. The appearance suggests thai we have a rock in which
the mica clement is jusl emerging into existence from Borne magma or is
checked in its emergence before attaining full development This is what I
have frequently denominated "nascent micaschist." It answers the descrip-
tion of the " tender mica schists" which characterize Hunt's " Montalbau
series," which, so far as 1 know, may occupy nearly the same horizon. Quite
a development of this formation occurs about the mirth end of White [ron
lake.

In the passage downward from nascent mica schist to the truly crystalline
schists, we sometimes arrive at a stadium in which minute and obscure de-
velopments of both biotite and hornblende may be detected. One almost
fancies the primitive ground material to have been in a condition of petro-
genic equilibrium. The impression is deepened by noting the predominance
of biotite at one point and the predominance of hornblende at another,
almost in the same hand specimen. These zones of doubtful supremacy are
narrow. In the immediate vicinity, some older bed reveals the presence of
characteristic biotite Bchist or hornblende schist.

At many points the transition from the semi-crystalline to the crystalline
>chi>ts is made without the intervention of graywacke. A very noteworthy
instance <<\' this occurs on the north shore of ( iunllint lake,* where the ver-
tical porphyrellitic argillites approach the gneissic area. At several points
on the lake shore the rock is observed to develop the feldspar crystals
which characterize porphyrel. Occasionally it develops quartz grains in-
stead, ami constitutes w hat is described near Vermilion lake as " porphyritic-
ally quartzose porodite." In the transition belt here alluded to this con-
dition of the rock receives also occasional dun or dark structureless patches.
These, farther on, assume a uralitic aspecl and then a hornblendic aspect,

and out of them emerge, in zones still nearer the gneissic area, > (times

uralitic hornblende individuals which, with quartz and feldspar already pres-
ent, give a uralitic gneiss. Sometimes also the dark patch'.- develop mien.
and in Buch case the ultimate formation is a good gneiss. The ground ma-
teria] gradually diminishes and finally ceases to appear.

A variation of the mode of transition may he Been at the same locality.
In this is an intervention of uralitic schist. The Bemi-crystalline schist
I . • • -_r 1 1 1 - as a sericitic or porphyrellitic argillite. It then becomes porphyrel,

wing harder and more crystalline. Next, the feldspar is Been to weather
reddish, while the rock ha- a Byenitic look. Still farther toward the gneissic
area the formation ig banded by belts looking like hornblende Bchist; hut
the hornblende is still of argil li tic softness, and there are line glistening

PROGRESSIVE TRANSITION OF ROCKS. 385

scales appearing like sericite, but in places recognizable as mica. Here,
then, are alternating sheets of porphyrel and crude uralitic and micaceous
schist. Now appear very thin laminae composed of feldspar, a hornblende-
like mineral, and ten per cent, of quartz. These continue to alternate with
the porphyrel. The alternations become exceedingly frequent, but the ura-
litic bands increase in breadth, and the whole terrane finally becomes a
uralitic gneiss, and soon after reveals the "coarse quartz individuals of the
well-known Saganaga gneiss.

It is hardly necessary to remark that the transitions mentioned are simply
progressive in a geographical sense. The historical or genetic succession
may have been the reverse, or the whole work may have been simultaneous.

Thus far the older rocks of the Northwest have presented a condition of
strict structural conformity. This fact was long unsuspected by American
geologists, but no field geologist of the Northwest entertains on this subject
the least doubt. What is even more striking is the gradual transition and
mutual blending witnessed in the passage from one of the systems enumer-
ated to the contiguous one. The facts provoke many theoretical inquiries ;
but I will only state that I do not regard the universal conformity of strati-
fication as evidence of the absence of geological breaks.

The Uncrystalline Schists.

On the north side of Gunflint lake the vertical schists are found overlain
by schists extremely different in character and attitude. They are nearly
horizontal, having a dip here of only about five degrees south by east.
They undergo a great development in northeastern Minnesota. They have
been traced westward well toward Ogishke-muucie lake. Eastward I have
traced them to Partridge falls ou Pigeon river. Between the national
boundary and Thunder bay they have been reported by Dr. Robert Bell,
of the Canadian Survey,* and on Thunder bay and in its vicinity they
have been described repeatedly by the Canadian observers. They constitute
the "Animike series " of Hunt, and by that name I shall for the present
refer to them. In Minnesota this is strikingly a thin-bedded, black argil-
litic series, rising in high bluffs along the south sides of the lakes and gen-
erally crowned by twenty-five to seventy-five feet of semi-columnar gabbro.
These characters present themselves at all outcrops as far as Thunder bay.
Certain strata, not very definite in position, receive dissemiuated grains of
quartz, and the formation thus approaches a proper black graywacke.
Within this system other strata, more definite in position, acquire a siliceous
character, and some become strictly beds of flint and jasper schist. Some of
these are brilliantly red or deep black, smoky, yellow, or chalcedonic. The

* Report for 18G6-'9, p. 322.

38U

A. \\ l.\( I1KI.I. — KESULTS OF A.RCHEAN STUDIES.

formation also embraces heavy beds of magnetite. More correctly, certain
beds become richly magnetitic. ami within limited districts arc dense eranu-
lar magnetite, oearly pure, and from two to lour feel t h i < -k. About Gun-
flint lake the argillites contain occasional pebbles and even become conglom-
eratic; :; but about Thunder Way they become well-developed conglomeratic
slates, and have been described as "slate conglomerates" and referred to
the lower member of the Upper Copper-bearing -cries.

The characters of the Aniinikc series arc so generally understood that I
-hull offer no further stratigraphical details in this place. Professor Irving
was acquainted with these rocks in their eastward extension ; but he Btrangely

Fioi u 8.— C 'I" Animikt and Kewatin Schists on the North S

This is the only point on the lake where the Kewatin comes to the shore.

K £ W A TIN

Cioubi •!.— /.' ativeF f the A

\ nflint Lake,

towing junction of the two systems and transition from Kewatin through orystalline Bchiste to
\ ertical dimensions «'xaKKerate<l, as usual.

identified them with the system of semi-crystalline schists. He was quite
aware of the great difference in attitude of the two; bul he argued that
perhaps their outcrops were located on opposite Bides of a granitoid area,
the uplift of which had tilted the whists to a greater extent on one ~ i < J « ■

than the other. He makes no menti f the discovery of an net mil <•■ »nt net .

with the two dips brought into immediate juxtaposition. He reports, how-
r, an increased • I i [ > of the A.nimike schists in approaching Gunflinl lake

ii io3, i<n

RELATIONS OF ANIMIKE AND KEWATIX SCHISTS.

387

from the east. This is a fact which I have ohserved, hut it is a local phe-
nomenon, and the normal flat-lying position is soon resumed.* I shall
therefore demonstrate that the Animike system is not one with the semi-
crystalline system. The nature of the observed contact on the north shore
of Gunfliut lake is illustrated in the accompanying diagrams, made on the
spot. Here are the two systems assumed by Irving to be identical, and to
have different dips in consequence of the remoteness from each other of the
portions compared (figs. 8, 9, 10). If you trust me for a correct statement

G*lMiro,.

Figure 10. — Observed Contact of Animike and Kewatin north shore of Gunflint Lake.

of the facts you cannot regard the semi-crystalline schists and the uncrys-
talline schists as both Huronian.f

I will here recall a diagram published by Professor Irving in an elaborate
memoir read before the National Academy of Science April 22, 1887, and
published in the American Journal of Science for September, October, and
November, 1887. The figure is given at page 261. % The first impression is
that he intended to represent the same state of things as I have shown. If

SE Keweerreurr Series

"Ve-vm-ilion
Trait. Series

Ora.nl.Te.

Figure 11. — Professor Irving's " generalized and partly idealized section of the northeastern part of

Minnesota."},

so, one would suppose that he knew nothing of it by personal observation.
The interpretation shows that he misconceived his own figure. The verti-

* Compare Seventeenth Annual Report Minnesota, 1888, p. 47

Jour. Sei., Oct., 1887, 3d Ser., Vol. xxxiv, p. 314— the communication being dated Aug. 2<), 1887.

JThe figure and the entire exposition of the relations of the Animike and the older schists are.
reproduced in the "Seventh Annual Report of the Director" of the U. S. Geological Survey, 1885-
1886. Printed 1888; received April 23, 1889.

§ This is his "generalized " illustration, and is here chosen because, in addition to the uncon-
formity, it explains Professor Irving's theory (or hypothesis) respecting the way in which the
Vermilion iron ores exist in the Animike.

38 \. W1M lll'l.l. — RESULTS OF \l:< IlKW STUDIES.

cal schists he refers a.< « irJitifc to the Bystem of crystalline schists. Ii i>
thus very easy to make the horizontal schists answer for the next overlying

-i. in above the crystalline. But the truth is that only the vertical schists
at the right or north of the diagram represent the crystalline schists and
gneisses, while those at the left of these, quite conformable in their verti-
cally, are the semi-crystalline schists. (Compare figure 9, above.) These
prolonged to Vermilion lake contain the great hematite deposits. In assum-
ing so violent a break between the crystalline schists and the next succeed-
ing group we have an indication that he had not yet remarked the universal
conformity which subsists between them. Such an unconformable contact
has been nowhere observed. In locating the Vermilion iron beds in a hori.
zontal formation, he must have forgotten the fact that they stand in a
vertical attitude.

Notwithstanding the earlier knowledge of the existence of an unconformity
at this place, I was myself, perhaps, the firsl to identify the two discordant
formations and appreciate the significance of their discordance. My brother
-;iv-: "This outcrop is -upposed to belong to what the Canadian geologists
have styled Buronian. It underlie- thequartzite and guntlint beds [siliceous
Bchists], apparently unconformably. At least it is another and distinct for-
mation from the slates at Grand Portage" {Report, L880, p. 82 . Return-
ing to this spot; in the Tenth Report \ for L881, p. ss he says: "The close
proximity of this flint and jasper locality to the next great underlying forma-
tion (syenite and slates i makes it one of great interest to the geologist, but
so far as scrutinized as yet the true relations of the two formation- are not
revealed by anything here Been, though there seems to be an unconforma-
bility between them." Professor [rving {Amer. .Jour. Sbt., \xxiv. p. 261
says: "On the north side of the latter [Gunflint] lake, and again to the
north of the next hike to the east, called North lake, the unconformable
abutment of the Animike series against an older formation of granite and
Bchists i- very handsomely shown." By "granite and Bchists" he means the
gneiss and crystalline schists, as is shown by naming the Animike flat-
lying schists as the horizon of the Vermilion ore- -contrary, however, to the
facts. In my announcement which appeared in the American Journal oj
Seienet for October, 1887, I said: "I have discovered the unconformable
Buperposition of the Animike Bchists on the Blates of the Vermilion b< i
[meaning the Vermilion iron-bearing Beries now called Kewatin]. The

• Pi later, the .same disproved Interpretatioi

itei thai in v description "i tit conformity »>»■< published

months later." in fact, it appeared in December. whil< Prol crip

Hon mber; but my first announcement was in October and Irvlng's was reallj in

ir Van n "I he :> i he

iimes that the schists referi mrringui fi

. i: tin- iron ores In and :•.>•••■; - tod Ely, Mum- sol i rhla

• » i Ighi i" take the question .-i-
•• myself traced their physical continuity sii timi impetenl on the

Mini ■ t, all together, no( in twenty-two times. This Is no

'• question

UNCONFORMITY OF ANIMIKE AND KKWATIN' SCHISTS.

389

Animike flint schists, dipping five degrees southward, have been traced by
me to within seven feet of the sericitic argillites of the Vermilion series,
dipping northeast about 67 degrees."

Other unconformable contacts of the two systems have been observed by
the Minnesota Survey. In travelling northward from Ogishke-muncie lake
the bowlders of the Ogishke conglomerate gradually disappear, and the
groundmass remains as an ordinary, evenly bedded argillite. At the distance
of two miles it becomes the porphyrellite schist so characteristic of the region
of the arms of Knife lake. Before reaching Knife lake, Epsilson lake is
passed. Here, on the north shore, the two systems of schists are seen in
contact. There is a general resemblance in external characters, and this is

K E W AT I N

A N I Ml I K I £

Fioure 12. — Showing Unconformity of the Animike «nri Kewatin Schists on EpsiTon Lake.

emphasized by the fact that the same system of cleavage passes through both ;
but the real unconformity of the two systems is revealed by the ribboning
of, the sedimentary bedding, which in the case of the Kewatin schists is
vertical and coincident, as usual, with the cleavage, but in the case of the
Animike schists is inclined to the cleavage at an angle of 43°.

I do not regard it necessary to cite in detail other examples of uncon-
formitv,but some will be found mentioned under the references given below.*

Classification of the Foregoing Rocks.

The enumeration which I have made embraces all the bedded rocks of
the vast region northwest of the Great Lakes, up to the so-called " Kewee-
nawan system." This is all there is of northwestern geology up to the hori-
zon named. So far, at least, as the great groups are concerned, the order of
succession is simple and plain. We may write them down with confidence
as follows, beginning above :

V. The Uncrystalline Schists (Animike, Huronian ).

IV. The Semi-Crystalline Schists (Kewatin).

III. The Crystalline Schists (Vermilion).

II. The Gneissoid Rocks 1 ,T N

t rru n ■* -a t? i C (Laurentian).
I. I he Granitoid Rocks J

^-Sixteenth Annual Report, Minnesota Survey, 1887, pp. f>7, 69, 73, 87, 357, 358; Seventeenth Report,
1888, pp. 87-8, 91, 104-'5, 109-'10.

LI— Bull. Geol. Soc. Am., Vol. 1, 1889.

390 A. \\'IN< IIKI.I. — RESULTS OF A.RCHEAN STUDIES.

Waiving the question of the taxonomic separability of the granitoid and
gneissoid rocks, the fundamental contrasts in condition seem fully to justify
the conclusion thai a historic break occurs above the gneissoid rocks and
another above the crystalline schists. A.bove the Bemi-crystalline .-dusts a
wide stratigraphic unconformity adds its evidence thai we find lure also a
boundary between two systems. The stratigraphic conformity between the
second and third, and the third and fourth systems is probably at variance
with prevailing opinions, and such a persistenl conformity of structure is a
fit subject for careful consideration. As I desire in this place simply to pre-
Benl tacts. [ will only Bay thai I do not imagine the present conformity im-
plies an original parallelism of beds of sedimentation.

The crystalline gradation, from bottom to top of the general aeries, is
simple and remarkable. There are no granites superior to the gneissic zone;
there are no gneisses superior to the zone of crystalline schists. A.bove the
zone of crystalline schists no true crystalline schists occur again. The
" nascent mica schists'' of the fourth section retain the palpable evidences of
their fragmental origin. We arc not mel by the anomaly of recurring mica
schists at two or three different horizons. As there was only one age of
gneisses, so there was only our age of mica schists. So, again, the fourth
was the age of argil lites, felsite schists, and volcanic tuffs, while the fifth lies
ou the hither side of a great continental movement, and is marked, like the
preceding ages, by characteristic lithologic conditions — its carbon-freighted
argillites, and its floods of silicated wat< rs.

With this observed simplicity of structure, we should entertain great con-
fidence in proposing a final classification were it not necessary to correlate
the results with those announced by eastern investigators. Where docs the
Huronian belong ? Where the Taconic? Where the Moutalban? Where
the l - -roup, and the other divisions of Ne\t Hampshire? We wish to
know, also, how these divisions stand correlated to the Dimetian, the Lewis-
ian, the Arvonian, and the iVlu'dian of ( Meat Britain, and with the divisions
of the Scandinavian scale. To some of these questions I have formulated
answers in my own mind: hut I do not deem it judicious to extend this me-
moir, for the same reason, 1 defer all the more detailed discussion on the
petrography of the Bevera] aystema and on all theoretical questions, such a-
the origin of the iron ores ami the accompanying Biliceoue and jaspi ry Bchiste ;
the conditions of origin of the pyro-clastic rocks; the cause .it' the foliation
in crystalline rocks; the relative agee of the granite- and gneisses; and the

testa and history of massive rocka which, by recenl opinion, have been by
• neral consent relegated to the class of eruptives.

DISCUSSION.

Professor C. R. Van Hise : If I were personally concerned only, I should
not occupy time by going into this question at all. I do not feel that my
familiarity with northeastern Minnesota would warrant it. Many geologists
know that Professor Irving gave a great deal of his time for several years
to an investigation of the formations of northeastern Minnesota. During
this time he was assisted by Mr. W. N. Merriam and Mr. W. M. Chauvenet,
so that the amount of time he has put upon this area, through his representa-
tives and in person, I can safely say far exceeds that of any other single individ-
ual; and I may say I think, although I am not so positive as to this, that no
other survey has given the region as much time as Professor Irving's.

Now, many of Professor Irving's conclusions are altogether different from
Dr. AVinchell's. Dr. Wiuchell began by stating that he intended to give
observations only. It seems to me before he had finished he put in many
theoretical conclusions. If the diagram drawn on the board (fig. 7) is not
a theoretical conclusion, involving as it does a thickness of sediments of over
100,000 feet,* I do not understand in what theory differs from fact. As to
the distribution of the rocks outlined by Dr. Winchell, I can bear testimony
to its general correctness, with the exceptions that I would not designate
certain of the rocks by the names which he gives them and would differ
from him as to the character of some of them, whether they are crystalline
schists or semi-crystalline elastics.

As to the correlation of these series, Professor Irving held tentatively, not
dogmatically, that the Animike series is the equivalent of certain sediment-
ary rocks in the Vermilion lake section as drawn by Dr. Winchell. As to
who first discovered the unconformity below the Animike I will not farther
discuss, but will only say that I know positively that Professor Irving recog-
nized it at the time he read his paper before the National Academy, in the
spring of 1887.f He recognized it to its fullest extent, and in this matter
agreed fully with Dr. Winchell. The chief point of difference is the relation
of the Animike rocks and the rocks which bear the iron ores at Vermilion lake.
These latter beds are in good part jaspery, and they are associated with rocks
which are distinctly semi-crystalline, yet are in places actually conglomer-
ates. The whole area west of the Animike series has been carefully gone

* Report upon a Geological Survey in Minnesota during the season of 1886 : Alexander Winchell :

is similar to
i aggregate of

scnlVts may be added the observed breadth of the gneiss on the north side, making a total thick-
ness of 106,204 feet," , ..„...,.,,

f Professor Irving and Mr. W. M. Chauvenet examined together the exposures at Ounriint lake
and saw evidence of the unconformity referred to in September, 1883. Professor Irving in his field-
note book (Sept. 6, 1883) sums upas follows: "The whole appearance [of the] topography, lithology,
persistence of rock beds is certainly suggestive of an unconformity here." Says Mr. Chauvenet in
his field notes : " There is here evidence of total unconformity."

(391)

392 A. WTNCHELL — RESULTS OF ARCHEAN STUDIES.

over by Professor Irving's survey. Thin sections of the rocks collected
have been made and examined in detail. The rocks were found to be crys-
talline schists. Still further to the west is the Vermilion lake series.*

It was Professor Irving's opinion that the fragmental and jaspery rocks
bearing ore at Vermilion lake, which are nowhere directly in contact with
the Animike rocks, are probably their equivalents. Dr. Winchell admitted
that the Animike rocks, besides exhibiting true bedding in certain places,
have a cleavage. Professor Irving believed that the section upon the board
I tig. 7) represents an intensely squeezed complex series (instead of a simple
conformable one 100,000 feet thick), the cleavage of which is secondary, just
as described by Dr. Winchell as occurring in the Animike rocks.

The reasons in detail for the above correlation would occupy too much
time to present to the Society. In general it was based upon lithological
likeness, not only of the- masses of the rocks as a whole, but of their individ-
ual members. It was based on the unlikeness which the Animike series and
the ore-bearing rocks and associated elastics of Vermilion lake have to tin
crystalline schists below the Animike and north and south of the Vermilion
rocks mentioned. It was based upon the comparison of these two groups
with the other iron-bearing series of Lake Superior. I can only refer you
to Professor Irving's elaborate memoirs for the many facts upon which he
rested his conclusion.

Finally, I would say that Professor Irving's ideas as to the complication
of the structure of northeastern Minnesota were quite different from those of
Dr. Winchell. Dr. Winchell holds that the structure in this region is ex-
ceedingly simple. It seems to me that the geological history of the Scottish
Highlands is instinctive in considering the geology of northeastern Al inix-
Bota. It was believed many years ago that the structure of the Highlands
was understood, but recent study has shown that the old ideas were largely
false; that its real structure is far more complicated than was believed; that
it is immensely complicated. The recent study of the Appalachian region
is teaching an exactly similar lesson. Professor Irving believed that the
crystalline series in northeastern Minnesota is the most complicated in its
structure of all of the regions about Lake Superior.

Professor Winchell: I trust it will not be assumed by this audience
that I undertook to attack Professor Irving's authority on the nature of any
kind of rock : least of all have I asserted or insinuated that he was nol

capable of determining whal is mica schist or crystalline Bchist. That i-
far aside from anything which I implied.-] The statement upon which my
friend Van Rise's assumption is grounded is simply my allegation that on

Por ili«- distribution of the formations under discussion .■>- lerstood by Professor Irvin

7th Annual Report, U. S Geol. Survej >*P»P ">.

| Por my estimate of Professor irving's abilities and servioi leenth . I mi. /.'. p \l

p. i ii, note.

MINERALOGICAL DIVERSITY OF THE ANIMIKE AND CEWATIN. 393

the north side of Gunflint lake there are vertical schists which are of the
Kewatin age ; they are semi-crystalline; they pass into crystalline schists by
gradual transition to the northward ; and it was my opinion that Professor
Irving either failed to observe that unconformity, if he were on the spot
and saw for himself, or else failed to notice that the schists upon the immedi-
ate shore of the lake, with which the Animike is in contact, were not proper
crystalline schists, but were Kewatin or semi-crystalline schists. I have
examined sections of these rocks and find they are not all the same thing,
but none are "crystalline schists." I will only say further that the Kewatin
rocks show sometimes a crystalline structure and at other times a partially
crystalline structure; at still other times an earthy condition. You can
get hand specimens that are entirely earthy in their structure and nature,
and you can get other hand specimens that are quite crystalline, but
nothing possessing the appearance of a mica schist. The groundmass is
generally one which is distinctly earthy, such as occurs within the limits
of the Kewatin.

Professor Van HrsE: Of course we shall differ as to the nature of the
schists which underlie the Animike series. I should regard them as far
more crystalline than the mica schists north and south of the Kewatin beds,
or, more accurately, than the beds bearing iron at Vermilion lake.

Professor AVinchell : It is a difference of opinion. Time does not suffice
to discuss the grounds of our differences. My positions are set forth in my
memoir, and it is not necessary to repeat them. I have also, indeed, indi-
cated there the diverse interpretations of Professors Irving and Van Hise.
The grounds of my dissent from their interpretations will perhaps be given
on another occasion.

My vertical section, thought by Professor Van Hise to be highly theoret-
ical is, I admit, partially so ; but if anything more than a mere help to the
understanding of the map, it goes but very little beyond a delineation of
facts actuallv observed.

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA

Vol. 1, pp. 395-410

POST-TERTIARY DEPOSITS OF MANITOBA AND THE AD-
JOINING TERRITORIES OF NORTHWESTERN CANADA

J. B. TYRRELL

OF THE GEOLOGICAL SURVEY OF CANADA

WASHINGTON

PUBLISHED BY THE SOCIETY

April, 1890

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA
Vol. 1, pp. 395-410 April 17, 1890

POST-TERTIARY DEPOSITS OF MANITOBA AND THE AD-
JOINING TERRITORIES OF NORTHWESTERN CANADA.

BY .7. B. TYRRELL, OF TIIL GEOLOGICAL SURVEY OF CANADA.
[Read before the Society December 27, 1889.)

CONTENTS.

Page.

The Region and its General Geological Features 395

The Glacial Deposits 396

Till 396

Terminal Moraines 398

Absence of Terminal Moraines near the Rocky Mountains 401

Western Pebbles 401

Direction of Ice Flow 401

Deposits of Isolated Glaciers 402

Drumlins 402

The Aqueous Deposits 402

Interglacial Deposits 402

Karnes t03

Lacustral Beds 403

Ancient Beaches 404

Discussion 40

The Region and its General Geological Features.

Southwest of the margin of what has loug been known as the Arcliean
continental nucleus lies a great drift-covered area, including in it most of the
plains and prairies of northwestern Canada. It extends on the international
boundary line from the western side of the Lake of the Woods to near the
eastern base of the Rocky Mountains, through between sixteen and seven-
teen degrees of longitude, or a distance of more than 750 miles. Towards
the northwest it stretches along the face of the Archean area to beyond the
arctic circle in the valley of the Mackenzie river.

Lying on an irregular floor of old gneisses and schists, rocks of Silurian
and Devonian age are known to occur over the whole eastern and north-
eastern portion of this district, while further westward these disappear under
others of upper Mesozoic age ; and thence westward to the foot of the Rocky

LII— Bum.. Shot- Soc. Am., Vol. 1, 1889. (39-r>)

396 .1. B. TYRRELL — POST-TERTIARY DEPOSITS OF MANITOBA.

M amain.-. < Iretaceous or Tertiary beds everywhere underlie the post-Tertiary
or recent deposits. The character of most of these bed-, which consist of
sandstones, marls, and clay-shales, is perfectly well known, but I wish to
draw your attention for a moment to the occurrence of conglomerates of
Miocene and Pliocene age, the existence of which has been pointed out of
[ate years, since they furnish sources of supply for a large amount of drift
which was formerly supposed to have been derived directly from the Rocky
M luntains at the same time that the other associated portions of the drift
were derived from the Axchean and Paleozoic rocks to the east.

The Miocene is at present known as a fresh-water formation of -and-.

silts, and gravel, or ( glomerate, lying on the eroded surface of the Creta-

U8 and Laramie rocks on the more elevated portions of the Hand ami
Cypress hills, and on the higher plateaus stretching east from these as far as
long. 1(,7- 1-Y. The pebbles in this conglomerate are all well rounded and
waterworn, and consist of a white quartzite similar to that in the Rocky
Mountains described by Mr. McGonnell as belonging to his"Bow River
group," or lower portion of the Cambrian system. This material has been
carried eastward by rapid streams during Miocene times, and deposited either
in lake- or on the flood-plains of rivers. The gravel has in many pla
been indurated by the infiltration of a calcareous cement into a hard con-
glomerate, much harder than the underlying -hales and sand-tone-, and has
preserved the hills that it now covers from degradation by atmospheric and
fluviatile agencies to the Bame extent as the surrounding country, and at the
same time has furnished a scale by which to measure the thickness of the
rocks washed away since Miocene time-.

The Pliocene, here called by Mr. McConnell the "South Saskatchewan
group," is al-o composed of rounded quartzite gravel : but it now occupies the
bottoms of valleys or other depressions, and has been derived in part from
the pre-existing Miocene deposits, and also in part directly from the quartzite
area- of the mountains.

The district under consideration, extending from the boundary between
the United State- and Canada northward to the North-Sa-katchewan river.
i- largely overlain by a series of heterogeneous deposits which are commonly
embraced under the term " drift." Tin- consists of bowlder clay or till.
morainic detritus including erratics, drumlins, kames, alluvial sands, clays,

and -ilt-, beach-ridges, terrace-, etc.

Tin. ( ii LCI \i. Mi POM i-.

Till. -The bowlder day <»r till rests irregularly on all the pre-glacial
formations down to the fundamental gneisses and schists, and in the A.rchean
area itself fills many protected depressions and recesses. I i - not. how-

r, reach the base of the Rocky Mountains, but extends westward to within

TILL OF THE SASKATCHEWAN PLAINS. 397

forty miles of them, as far as Calgary, on the Canadian Pacific railway, and
from there southward to the international boundary it keeps at about the
same distance from the mountains. North of Calgary the western edge of
the great sheet of till crosses the Red Deer and North-Saskatchewan rivers
at approximate elevations of 3,000 feet above the sea, the latter in long.
11")° W. Further north it is stated by Dr. Dawson to cross the Peace river
in lat. 56° N., long. 119° W. To the south its boundary everywhere lies
on the United States side of the Forty-ninth parallel of latitude. North
of or near this geodetic line it covers all the country of the plains without
regard to elevation, with four exceptions, viz., the upper portions of the
Sweet Grass hills above 4,660 feet, the Cypress hills above 4,400 feet, the
Hand hills above 3,400 feet, and Rocky Spring plateau above 4,100 feet.
The general character of this great sheet of drift is remarkably uniform
throughout, being essentially composed of a gray, more or less sandy clay,
massive in character, and holding numerous pebbles and bowlders. It is
largely composed of the debris of the Cretaceous and Tertiary rocks that
surround or immediately underlie it, consisting probably of the parts of
these strata that were rotten from long exposure to the weather during the
ages that intervened between the close of the Laramie period and the com-
mencement of that of glaciation. By this latter agency the rotten rock was
kneaded up, with the bowlders and pebbles transported from a distance, into
a homogeneous mass. That the till is local is clearly seen where the under-
lying rock has any very marked characteristic by which it can be recog-
nized— as, for instance, the rocks of the Edmonton series of the Laramie,
which are associated with numerous beds of lignite. Overlying these rocks,
and especially for some distance south of a lignite outcrop, the drift is filled
with pieces of lignite sometimes as large as a hen's egg, and the whole mass
becomes dark in color from its presence in minute fragments. Another in-
stance is recorded by Dr. Dawson where the drift has a distinctly reddish
tint, derived from some neighboring reddish clays of the Laramie formation.
The bowlders are, however, largely of eastern origin, being composed of
granitoid gneiss, mica-schist, quartzite, diabase-trap, gneiss-conglomerate,
and stratified Paleozoic limestone, those of limestone, as well as an occa-
sional one of the other rocks, being usually irregular in shape, with smooth,
polished surfaces and sharply marked glacial strhe. The pebbles included
in the till throughout the western portion of the district, where they consist
largely of white quartzite, the same as that composing the Miocene gravels
on the Cypress and Hand hills, are doubtless partly of local origin, having
been derived from the gravel on these hills, or from other areas that have
been entirely denuded away. Some are also probably derived from the
parent beds of Cambrian quartzites in the Rocky Mountains. A few of
gneiss are almost everywhere met with, and while the western quartzites

398 i B. fYRRELL — POST-TERTIAR"* DEPOSITS OF MANITOBA.

gradually disappear on proceeding eastward those of gneiss become more
numerous, and pebbles of Paleozoic limestone also become very common.

In thickness the till varies greatly in different places, ranging down from
500 feel or more to a very thin covering; but, generally Bpeaking, throwing

oul of account deposits clearly referable to terminal moraines, it be< ies

slightly thinner from cast to west, the outcrops seen along the 3,000 fool
contour line above mentioned being as a rule not more than a few feet in
thickm -

Throughout the greater portion of the area under consideration the till
falls naturally into two major subdivisions, a lower very compact bluish-
gray unstratified deposit, and an upper softer and sometimes thickly lamel-
lated clay usually of a light brownish color. These two subdivisions have
been chiefly recognized in the extreme western portion of the area, from the
international boundary north to the North-Saskatchewan river, where they
are often separated by stratified waterlaid deposits, in which, on the Belly
river. Dr. Dawson records the occurrence of a bed of lignite eight inches in
thickness. The till in this latter locality is also of extraordinary thickness
as compared with the average found farther north between the How and
North-Saskatchewan rivers. Farther easl these two subdivisions have not
been so generally recognized, probably on account of the great thickm --
of the whole deposit and the comparative paucity of g I sections.

Terminal Moraines. -Intimately associated with the till are a number of
irregular ridges of rounded hill< severed by deep depressions, in the bottoms
of which are often lakelets of char, sweet water without visible outlets

'The rim of the basin of oi f these lake- i- frequently fifty or sixiv feel

above the surface of the water, and surrounding knolls in many cases rise to
a height of from a hundred to a hundred and fifty feet higher. Sections of
these hills Bhow them to be masses of transported material, consisting of un-
stratified sand, clay, and bowlders, and their Bides and summits are almost
always thickly strewn with large northern or eastern erratic-.

A - to the mode of formation of these hilly tracts, t here is now little room
for doubt that they were the terminal moraines of one or more extensive
glaciers that moved outward- from the central Archean nucleus, planing off
the higher point- of the surface and shoving before them the accumulated
mass of mixed material. Much of this fell hack under the moving ice in
the depressions of the preglacial Burface, while the rest, consisting chiefly of
the coarser material, continued at the ice-foot, and was left as an irregular
ridge on the final retreat of the -lacier. Very few of these morainic belts
have as y< i been definitely located, but the following may be mentioned
some that have I,. m examined in late y< ars and whose character is pretty

ainl v know n.

< >n the western margin of the Winnipeg basin, a rugged morainic ridge

CANADIAN TERMINUS OF THE MISSOURI COTEAU. 399

runs along the face of the northern continuation of the Pembina escarpment,
with a mean elevation of 1,600 feet. In the great depression drained
by the Valley river its width is from a quarter to half a mile. It is com-
posed chiefly of sand, but it also contains very many large bowlders of dark-
gray and reddish gneiss, mingled with others of Paleozoic limestone.

Proceeding a little further to the west, the whole surface of Duck mount-
ain is found to consist of irregular ridges aud knolls of gueissic debris ris-
ing in some parts to a height of 2,000 feet above Lake Winnipeg, or 2,700
feet above the sea. This rugged tract extends southward over the summit
of the Riding mountain, and it is not improbable that the Brandon hills
(which have been described to me as having somewhat similar characters to
those already mentioned) may be a southern continuation of the same ex-
tensive ridge.

Proceeding still farther westward along the Forty-ninth parallel of north lati-
tude to the westward margin of what has been known as the second prairie
steppe, a wide belt of rounded morainic hills is reached, lying on a sloping pre-
glacial surface rising gradually from east to west. This hilly country, which
has been known since the time of the early voyageurs as the Missouri Coteau,
was well described by Dr. Dawson in his report on the geology and resources
of the Forty-ninth parallel. It has also been identified by Professor T. C.
Chamberlin as the continuation of the great terminal moraine of the second
glacial period, which has been traced by himself and others from Dakota
eastward to the Atlantic Ocean. From the northern boundaries of Dakota
it has been traced by Mr. McConnell northwestward in Canada for two hun-
dred miles to a point on the South -Saskatchewan river, twenty-five mile above
the elbow, crossing the line of the Canadian Pacific railway in the vicinity
of Secretan station. North of this point its course is not at present known,
and it must be borne in mind that north of the Fifty-first parallel of north
latitude the plains lose to a great extent their eastern slope, the summits
of the Duck mountain, in long. 101° W., being equal in height to the gen-
eral surface of the country due west of them in long. 113° W\, or more than
five hundred miles distant. Since, then, the slope on which the moraine con-
stituting the Missouri Coteau was deposited becomes very indefinite or dies
out a little north of the South-Saskatchewan river, it is not improbable that
the course of the moraine itself is much changed, so that it may curve around
and join others that are now known to the east or west of it. It is, however,
more probable that it is here an interlobate moraine, and that as a definite
entity it does not extend much further north than its present known limit.

West of the Coteau the till is of essentially the same character as that to
the east of it, and numerous detached ridges of " rolling hills " or terminal
moraines are known to occur. In describing the vicinity of the Cypress
hills Mr. R. S. McConnell classes with the Coteau, as being " covered with

lllll J. B. TYRRELL — POST-TERTIARY DEPOSITS OF MANITOBA.

steep-sided drift-built bills," the " ridge extending northwesi from Pinto-
horse butte" ar the bead of the middle branch of Old Wives creek and

in approximate hit. !'.• IV N., long. 107° 45' W.) in a general direction
parallel to the Coteau and about fifty miles southwesl from it, ami the "spur
south of tin- west end of the Cypress hills " a hundred mile-, still farther
west.

West <>f this ridge ami south of hit. 51 N. no terminal moraines have
been recognized, except such a- have been formed by glaciers flowing from
th<' valleys in the mountains, thro- heinu; characterized by the angularity of
the included pieces of rock and the absence of eastern erratics. North of
hit. -*>1 N'. tin- re a iv a number of ridges of distinctly morainic character.
( me of the most typical of these surrounds the southern and eastern sides of
the Sand hills. These Latter hills form a high table-land rising twelve hun-
dred feet above the surrounding plains, and are surmounted by two hundred
and seventy feet of sands, silts, and gravel of Miocene age. Towards the
northwest, west, and southwest they rise in an abrupt escarpment five hun-
dred feet to their summit ; towards the east and southeast they decline grad-
ually and regularly for a short distance, aud then the slope is covered with
a ridge of roundel knob-like hills separated by deep kettle holes, in the bot-
toms of which often nestle small isolated lakes. Their summits are thickly
overstrewn with bowlders.

From lift v to sixty miles further north, near the southerly bend of the
Lied Deer river, another similar ridge is met with, the knolls rising in many
places to i e than two hundred feet above the bottoms of the depressions.

Turning directly eastward a rough, irregular tract, known as the Neutral
hills, is seen, the higher points of which arc thickly covered with gneissic

and limestone erratic-, lying on a base of unmodified morainic material.

The hills themselves lie on an elevated plateau of Cretaceous shale, which
has been very irregularly eroded, ao that it is often difficult to say without
Sections whether an individual hill is a product of denudation or is one of
the irregularil ies of the moraine.

North of the Battle river the Blackfoot hills form another area of deep,
uuconnected depressions and high, rounded knolls, sprinkled over with
h iwlders of eastern gneiss.

Other morainic belts doubtless occur in this area south of the North-Sas-
katchewan river, hut as yet they have not I a traced out. Enough has

I, en done, however, to -low the former existence of a great -lacier, or " mer
de glace," which spread over the plain- from a source or Bources of supply
.,n or north of the Archean rock- to the east, and which flowed in a southerly
and southwesterly direction almost to the foot of the Rocky Mountains,
from whose valleys numerous small glaciers flowed eastward to join the
mighty advancing ice-sheet, leaving intervening ana- along the lorn of the
mountains, and roughly west of the 3,000 foot contour Line, unglaciated.

GLACIER PROBABLY TERMINATED ID STANDING WATER. 401

Absence of Terminal Moraines near the Rocky Mountains. — The absence of
a terminal moraine at the extreme western limit of the till, near the foot of
the mountains, is a fact worthy of notice, especially in view of the fact that
the till of both the earlier and later glacial periods is found to extend
approximately the same distance westward, and that there is a narrow belt
from thirty to one hundred miles in width that would appear never to have
been covered by the ice-sheet.

The most efficient reason that suggests itself to me to account for this state
of affairs is that the glacier terminated in one or more lakes, hemmed in
between the continental glacier and the mountains and cut off towards the
north and south by lateral glaciers flowing eastward in such valleys as those
of the Bow and North -Saskatchewan rivers. The morainic accumulation
would in that case be carried off either by icebergs or waves and currents
and spread out some distance beyond the limit of the till. This would
account for the presence of eastern erratics along the very foot of the
mountains, and may also account for the high terraces on the sides of such
valleys as that of the North Kootanie river. This condition could not,
however, have lasted for any great length of time, as no considerable amount
of stratified deposits are found in this unglaciated area.

Western Pebbles. — The presence of western pebbles in the drift far out on
the plains was for a long time an almost insuperable barrier to the general
acceptance of the belief in its essentially eastern origin ; but the discovery
of large areas of Miocene conglomerates, holding these same pebbles, as far
east as long. 107° W., has almost entirely overcome this objection in furnish-
ing new centres of distribution from which these pebbles have been carried.
Still it is not improbable that some of the drift in the extreme western part
of the drift-covered country is derived from the mountains, having been
carried down by the local glaciers mentioned above.

Direction of Ice Floiv. — In speaking of the general direction of flow of
the western portion of the great continental mer de glace it has been
customary to regard it as having advanced southwestward from the Archean
area — and certainly this was the direction of glacial motion when the ice
first reached the Winnipeg basin, — but recent investigations have shown
that in two cases, at all events, this direction was not sustained, viz., in the
great Winnipeg valley, and in the valley of the upper Assiniboiue, west of
the Duck and Riding mountains. In both these cases the direction of flow
was southward or southeastward in the direction of the trend of the valleys,
and parallel to the main axis of the Rocky Mountains. This direction was
in all probability sustained by the glacier all the way across the Canadian
plains, and we have thus one reason for its great extent, as the ice was moving
from a wide area of distribution to a much narrower area of dissipation,
and there would be a constant tendency to make up for the loss from the
surface by a crowding in from the sides.

1:02 .1. B.TYRRELL — POST-TERTIARY DEPOSITS OF MANITOBA.

Deposits oj Isolated Glaciers. — Afterthe final retreat of the general con-
tinental glacier, relatively small neves remained on the tops of sonic of the
higher elevations that had previously been overridden, and small glaciers
flowed outwards from them down valleys of various depths. The Duck
mountain shows many evidences of having passed this intermediate stage of
local glaciation. It is a high table-land, the summit of which rises '_\7<)»>
feet above the sea, or 2,000 feet above Lake Winnipeg, and consists entirely
of Cretaceous clays overlain by a great thickness of unstratified till and
transported bowlders, most of the latter being Archean gneisses and schists.
From the summit of the mountains several large valleys carry the super-
fluous drainage outwards to the various surrounding waterways. The strati-
fied deposits in these valleys are in many cases overlain by unstratified till.
The valleys are also blocked by small local moraines, behind which in some
cases the valleys are terraced as high as the tops of the moraines, while in
others the rivers that formerly occupied them have been permanently di-
verted into other channels.

Thus we would appear to have in this area three distinct bowlder clays,
two formed by the continental glacier moving southward, and the third or
upper formed by local glaciers existing at the same time that the great post-
glacial hikes filled all the adjacent depressions.

Drumlins. ( )ver the great portion of the plains drumlins have not been rec-
ognized, possibly in part because in the press of other work they have not been
looked for sufficiently; hut. in the northern portion of Lake Winnipegosis
many excellent examples are to be seen. They here form groups of narrow,
very much elongated elevations in the till, rising in islands a few feel above
the sin lace of the lake, and are generally thickly covered with transported
bowlders of gneiss and limestone. A very casual glance at these group- of
islands will serve to show that they are structurally different from neighbor-
ing one- underlain by rock and on which the bowlders have been shoved by
the ice. There is do Bign of any rock in place and the stones are not all of
constant lithological character, a- is generally the case where the rock is

close to the -urrace, hut they are t rue transported bowlders, differing as widely
from each other a- crystalline gneiss and coralline limestone. The Islands

are also formed with their long axes parallel to the direction of the glacial Btrise
In i lie vicinity.

Tin-: Aqueoi - I >i posi re.

Interglacial Deposits. As has been already shown, the evidence- of a re-
currence of glacial conditions and the intervening temperate era uear the
northwestern limit of the glaciated area have no room for doubl that the
glacier retired tor a considerable time from the greater pan of the western
prairie region ; and perhaps during this interglacial period conditions may

ECONOMICALLY IMPORTANT AQUEOUS DEPOSITS. 40o

have been much as they are now, for near the northern end of the Duck
mountains there is a deposit of stratified silt underlying a great thickness
of unstratified till, and probably of inter-glacial age, holding numerous
fresh-water shells, with fragments of plants and fish remains essentially the
same as those living in Lake Manitoba and the surrounding lakes to-day.

Karnes. — Very few kames have up to the present been definitely located
in the Canadian northwest, and none that would appear to have been con-
nected with any but the later stage of glaciation, viz., that of isolated local
glacial centres. The most important of these stretch as straight ridges down
the middles of deep valleys on the east side of the Duck mountain. The
two most important ones recognized were covered by several feet of pebbly
unstratified till, the same as that composing the surrounding hills. In some
cases what have been taken for moraines may possibly be kames, but it is
difficult in all cases to distinguish them in the absence of sections.

Lacustral Beds. — Resting on the bowlder clay throughout very extensive
tracts in Manitoba and the North West territories are stratified sands, silts,
and clays that have been deposited in the bottoms of post-glacial or recent
lakes. The delineation of these lake basins is a work of the greatest economic
importance, as it is evident from what we at present know — that many of the
most fertile tracts in the west are underlain by rich alluvial clays deposited
in the bottoms of sheets of water of greater or less extent, which have now
disappeared.

The number and extent of most of these old lakes has not as yet been de-
termined, but the positions of a few may be here generally indicated.

The country drained by the upper waters of the Bow, Red Deer, and North-
Saskatchewan rivers, having at present a mean elevation of between two
and three thousand feet, was largely submerged, fine clays and silts over-
lying the till being here very generally met with, though no shore lines have
been recognized. A marked peculiarity of these deposits is the utter absence
in them of any shells or other fossils that would indicate the existence of
life in the lakes in which they were deposited.

Another extensive stratified deposit skirts the eastern margin of the Mis-
souri Coteau.

The depression lying west of the Duck mountain, which is now drained
southward by the Assiniboiue river, was also, at the close of the glacial
period, the basin of a large lake which first drained eastward through the
valley of Short creek and Valley river, between the Duck and Riding
mountains, and afterwards, when this valley was blocked by a local glacier
from the Duck mountain (the terminal moraine of which still stretches
across its western end), cut out the present valley of the Assiniboine. South-
ward, this lake extended down to lat. 51° N. Its northern and western
boundaries have not yet been determined ; but standing on the morainic

L HI— Bull. Geoi,. Soc. Am., Vol. 1, 1889.

Mil J.B.TYRRELL — POST-TERTIARY DEPOSITS OF MANITOBA.

ridge thai forma the western side of the Duck mountain, and which was also
the eastern shore of the lake, a wide, level, alluvial plain or lake bottom may
l>f seen stretching westward to the limits of vision.

But by far the Largesl and most important of these ancient post-glacial

lakes is that named Lake Agassiz h\ Mr. Warren Qpham, and which once
occupied the Winnipeg basin and the valley of Red river. In its bed was
deposited the rich alluvial clay that is now enabling Manitoba to take its
place as one of the foremost wheat-producing areas in the world.

Ancient Beaches. — I shall not now discuss the altitude, length, and depth
of these lakes; but a few words may be said of the beaches that at various
times formed the shore lines tor the gradually receding waters.

The existence of the old shores of Lake Agassiz was clearly pointed out by
Professor H. Y. Hind in L859, but their relative heights were not at all
understood by him. Of late years M r. Warren Upham has carefully studied
these beaches from Lake Traverse, at the south end of the Red river valley.
in a short distance north of the 50th parallel of north latitude. In the

w led district further north, and one hundred and fifty miles north-north-

wesl from where the old lake beaches cross the international boundary at
the foot of the Pembina escarpment, several gravel ridges were located by
the writer on the northern face of the Riding mountain, close to the hanks
of Ochre river, a small stream ilowing into Lake Dauphin. The heights of
these ridges are respectively 1,215, 1,115, and 1,025 feet above sea level.
From Ochre river they were followed for eighteen miles in a northwesterly
direction, at the end of which distance the highest one runs along the summit
of a steep escarpment one hundred feet in height, while the one below it i-
continuous with the line of the base of the cliff. The face of the cliff is now
overgrown with trees, but a gulley that cuts back into it shows it to be com-
posed of the white limestones and chalk-marls of the Niobrara subdivision
of the ( iretaceous.

The sequence of events is here very beautifully shown: For a considers
ble time the lake atood at the level of the highest of these beaches, and the
land -loped gradually beneath the surface of the water. The lake then fell

more or less rapidly a hundred feet to the Qexl lower shore line, and must

have stood at this level for a long time, sufficiently long at all events to

allow the waves t" <ut a cliff of limestone one hundred feet in height from

what was before a gradually declining Burface.

From this chalk cliff, which formerly must have -i I out boldly a- a

conspicuous landmark on the shore of Lake A.gassiz, coasl ridges were again
followed and crossed al interval- in travelling uorthward to Valley river.
This stream How- in a wide depression separating Duck from Eliding mount-
ains, 'lie- highest beach ridge seen on it- hanks has an elevation of 1,280
feet above the sea, hut above this is an extensive sandy plain covered with

BEACHES OF LAKE AGASSIZ. 405

stunted grass and dotted with a few scrubby oak trees. This plain is a
delta deposit of a river that flowed into Lake Agassiz when this lake was at
its highest stage ; and on the sides of the channel which the present river
has since cut through the plains a number of very interesting and instruct-
ive sections can be seen, including both the superficial deposits and the un-
derlying Cretaceous.

Beyond the Valley river the ridges continue in a direction 15° west of
north for sixty miles, to the northeast angle of the Duck mountain, when
they turn abruptly westward into the valley of Swan river. Crossing this
valley they are well marked on the eastern face of the Porcupine mountains,
north of which they turn westward for a long distance into the vallay of
Red Deer river, ending in a wide, flat, sandy delta plain.

Whether they extend along the face of the Pasquia mountain has not
yet been determined ; but the Pas ridge oh the Saskatchewan river would
appear, from descriptions we have of it, to be one of these ancient beach
ridges, though its elevation is not nearly so great as most of the well defined
ridges along the face of the Duck and Porcupine mountains.

These beaches as a rule are in the form of slightly rounded ridges from
> fifty to two hundred feet high, raised from three to twenty-five feet above
the surrounding country. They are composed of sand and small water-
worn pebbles, a few of which are granitic or quartzitic, while a great ma-
jority are of the white Paleozoic limestone at present outcropping around
the adjoining lakes. The gravel must, however, have been derived entirely
from the till that had previously been carried by the glacier from the bedded
rock at a distance, for there is now no known outcrop of these limestones
with a greater elevation than about nine hundred and thirty feet, or more
than five hundred feet below the summit of the highest of the gravel ridges.
Cliffs of till that might furnish sources of supply for the pebbles are also
often separated by very long intervals ; so that it is probable that most of
the gravel was brought down by rapid streams flowing from the adjoining
mountains, and was distributed by currents along the shore.

The beaches would appear essentially to have been formed by waves and
currents, as there are very few signs of ice action such as are seen around
the shores of Lakes Winuipegosis and Manitoba to-day.

Where most conspicuously developed the beaches are covered, as a rule,
with only a meagre growth of short grass, which in some of the more north-
ern parts is varied with a few stunted trees of Banksian pine. They thus
often form beautiful dry roads through country that would otherwise be an
impenetrable forest.

So far as the eye can detect, the line of the crest of the ridge is quite
horizontal, but careful measurements show it to rise gradually and regularly
towards the north, just as the crests do in Minnesota and Dakota. At

1:06 J.B.TYRRELL — POST-TERTIARY DEPOSITS OF MANITOBA.

the boundary line the ridges range in altitude from 995 to L,230 feet above
the Bea,* while <>n th<- eastern nice of the Duck and Eliding mountains they
were found to ascend as high aa 1,460 feel above the Bea, showing a rise in
the upper boundary beach, supposing it to continue this far north, of about one
fool to the mile from the point of crossing latitude 40° north to the Duck
river, where the bighesl lunch was seen, [f the highest beach at the bound-
ary does not extend so far north, the rise per mile will be somewhat greater.

Very few fossils that can be clearly identified have been found in these
-ravel ridges; but on Valley river in hit. 51° 13' N.. Long. L00° 20' W\. at
a distance of two feet below the surface, some roughly chipped fragments of
quartzite have been discovered, lying horizontally among the disk-shaped
waterworn pebbles, along with a small bone of a mammal. Precisely simi-
lar fragments are now to be found on the shore- of lakes VVinnipegosis and
Manitoba in association with well-formed arrow-points, and the traditions
of the Indians go back to the time when they were formed and used by their
forefathers. A- the gravel had been laid down bv water action and was
quite undisturbed, they clearly indicate the existence of man at the time
when this lake beach was being thrown up, and it is probable that here,
mar the mouth of the former representative of Valley river, was one of his
favorite haunts. The summit of the beach in which these "chipped flints"
were found is bio feet above lake Winnipeg or 1,135 feet above the sea.

The positions of the northern and eastern shores of Lake Agassiz have not
yet been determined : but from what we know at present we can safely say
that there is no land in that direction sufficiently high to form a shore line
with an elevation of 1 ,400 or more feet, ami there has been no evidence forth:
coming to show that there has been any other disturbance of the country
since the lake was at its highest level than the slow uplift towards the
north shown by the gradual rise of the ridges in that direction. Tin- theory
ha- been suggested that the face of the retreating continental glacier held
back the water on these two sides. It is not improbable that a- the glacier
retired from the face of the country, which was sloping towards it, a lake
would In formed at it- foot. If this be the true explanation of the cause of

the formation of Pake A.gassiz, it discharged its surplus water through the
valhy of Lake Traverse until the glacier had retired far enough or had
decreased sufficiently in size to allow id' a discharge for the lake over or
around it. The position of this river has not been and may possibly never

be determined, a- all traces of it may have since been swept away.

Much ha- yet to I"- learned of the history of all of these post-glacial lake
beaches, but a long array of interesting facts is now being gathered together,
which it i- hoped will before long solve Bomeofthe mysteries of Quater-
nary dynamical geoloj

rhe Upper Beache* and Oil lal Lake I by Warren Upham: Ball. 301 -

Or., I. - p 17.

DISCUSSION.

Mr. J. E. Mills: I should like to mention, in connection with this paper,
General Warren's account of the canon of the Mississippi. He traced the
Mississippi canon up to that of the Red river, and thence on to Lake Winni-
peg. He inferred from what he saw that the canon when first formed was
higher than now, and that the waters of the Winnipeg flowed at that eleva-
tion southward. He inferred, also, that the canon was formed by a river
much larger than the present Mississippi. General Warren announced this
about 1869. I had the pleasure of doing a part of the geological work of
his survey. If I understand Professor Chamberlin rightly, the canon was
excavated between the two glaciations. In that intermediate period the
drainage of Lake Winnipeg was southward through the Mississippi valley,
and if General Warren's account is correct, the country north of Lake
Winnipeg must have been drained southward. Professor Chamberlin shows
that at this very time the country of the lower Mississippi was at base level —
was very low. There certainly was an elevation, therefore, that caused the
erosion of the Mississippi canon about that time. This seems to confirm and
strengthen General Warren's deduction that there was an elevation, and
an elevation increasing northward. I should like to have Mr. Tyrrell state
what bearing his observations have upon this deduction of General Warren's.

Mr. Tyrrell : The problem of the direction of the preglacial drainage of
the Lake Winnipeg basin is a long and complex one. I can merely say here
that much of the evidence at present in hand goes to show that it was drained by
a river flowing with a more or les3 northerly course. I know of no evidence
found in Canadian territory that will serve to indicate the direction of drain-
age in the interval between the first and second glacial periods. In the
Winnipeg basin the tracks of the older glacier have been obliterated or
greatly obscured by the severe erosion of the later glacier. Generally speak-
ing, one must look farther south or nearer the ancient ice-front for the clearest
evidence of the earlier glaciation, though it is quite probable that inter-
glacial beds exist in Manitoba. In the postglacial period the Winnipeg
basin was first drained southward through the valley of Lake Traverse and
down the Minnesota river, and afterwards in a northerly or northeasterly
direction, as at present.

On this latter subject, however, I beg to refer to President Chamberlin,
who has given the matter a large amount of attention.

President T. C. Chamberlin : The cutting of the trench from the outlet
of Lake Agassiz down to the Mississippi was a work which followed the
main glaciation of the second period, and was not a part of the great trench-
ing of the Mississippi to which I referred in my paper.

(407)

10S J.B.TYRRELL — POST-TERTIARY DEPOSITS OF MANITOBA.

I tliink we should be scarcely less than stolid — we of the United States — ■
if we did cot strike hands with our brethren across the border over a
paper which brings into such beautiful consonance the phenomena on the
two sides of the international boundary. This paper Bets forth the phe-
nomena of the great plains on the north of the boundary in precisely the
same terms and under the same interpretations that we have been accustomed
to use on our side of the line.

That which strikes me most, beyond this gratifying consonance, is the
remarkable extension of our knowledge which this paper and the two pre-
ceding papers relating to the northwestern part of our continent* give US
with respect to the delimitation of the ice sheets. The boundary line in the
western portion of the plains of the Dominion has been represented as ex-
tending nearly parallel with the foot of the Rocky Mountains down to our
boundary. It continues essentially parallel to the Rocky Mountains south-
ward in our territory to the vicinity of the Sun river, then curves easl and,
crossing the Missouri river, swings northward on the north Hank of the
Lightwood mountains, and thence northeast until it strikes the Missouri
again at the mouth of the Judith river; then, swinging back, it courses east
to the vicinity of Bismarck, where it once more turns south and keeps near
the course of the Missouri river until it strikes the Mississippi. So the de-
limitation in the western portion of the Dominion i- brought into perfect
harmony with that reported by the United Slates Geological Survey.
Taking this in connection with the facts given in the preceding paper, it is
scarcely a jump of interpretation to project this line along the foothills of
the Rocky Mountains north to the border observed in the Mackenzie basin,
and thence on to the delta of the Mackenzie, which practically carries the
delimitation to the A rctic sea.

The limitation of this border to a line oil' the eastern base of the Rocky
Mountains is a remarkable facl when we consider the low condition of the
plain- easl of them: and the further fact that the glaciers of the Rocky
Mountain- had only a moderate extension is very remarkable. We must bear

in mind thai these mountains are very high and very broad, and that there

sweep over them breezes bearing an unusual load of moisture, much more

than the winds that sweep over the Scandinavian mountains on the other
Bide of the Atlantic. Yet, notwithstanding all these highly favorable con-
ditions, they were not the source of any extensive glaciation, but, on the
contrary, the great glaciation came from the far lower heights of the eastern
part of the continent and spread across the vast Btretches of the great plains.
This, ii Beeme to me. is a fad of profound consequence, and its colossal
character ought not to be overlooked.

i I Russell and R <• McConnell; the former printed among the memoirs (pp. 09 162), and
the latter in the proceedings, in this roluma.

PLEISTOCENE SUBMERGENCE ON THE ATLANTIC COAST. 409

Professor N. S. Shaler : I should like to ask whether this evidence,
brought to us from north of the boundary to the United States, does not go
still further and show that the last glacial period in North America was in
some way connected with the conditions of the northern Atlantic ocean ?
The evidence now goes to show that it is a symptom of climatic conditions
on the north Atlantic ; and therefore it is our task to interpret the phe-
nomena by the facts that have taken place in that ocean basin. It seems to
me it is by the increased precipitation of the vapors taken from the warm
waters to the sea that we may most easily explain the conditions of the last
ice period.

I have recently had an opportunity to study the surface geology of Florida,
and it seems to me probable that in the glacial times, or about the time of
the last glacial period, the Gulf Stream flowed freely over the surface of
Florida up to the northern portion of the lake district. The appearance
of Florida seems to indicate that the tide at this time extended from the
northern part of the lake district to the Cuban shore. It seems to me likely
that we may attribute a glaciation in the eastern part of Europe and Asia
and the northern part of North America to the changes in the flow of this
stream dependent on modifications of the coast line topography of the region
of the Caribbean and the Gulf of Mexico.

Mr. W J McGee: I have recently ascertained that during early Pleisto-
cene time — during the first of the two great ice invasions which all geologists
are recognizing — not only was all of Florida submerged, but two-thirds of
Georgia and the greater part of South Carolina. The submergence in South
Carolina reached 550 or 600 feet, and over the low-lying plains there lies a
mantle of coast sands deposited during the period of submergence. These
coast sands have been found continuous Avith the Columbia formation of
the northern part of the Atlantic slope.

Dr. J. W. Spencer : With the conclusions of Professor Shaler and Mr.
McGee I concur. I have seen apparent Pleistocene deposits in Alabama at
about 675 feet above the sea. Over plains and hills of the great Northwest
of Canada, also, I have seen bowlders scattered upon the surface of both
Paleozoic and Cretaceous rocks. In many cases these are of secondary origin,
having been left upon the washing away of the finer materials from the older
bowlder clay. Few or none of those erratics which I have seen have been
primarily derived from their original sources, although many have been
again transported by the floating ice of now shrunken or extinct lakes or
seas.

From the occurrence of elevated beaches described by Mr. Tyrrell and
others in the North West territories, and from the remains of still higher
beaches about the Great Lakes, I am inclined to generalize and bring down
the whole continent to make the beaches mark sea-level in the last stages of
the Pleistocene period after the episode of the last till.

110 J.B.TYRRELL — POST-TERTIARY DEPOSITS OF MANITOBA.

Mr. Tyrrell: I may say ;i word with regard to the bowlders referred to
by Professor Spencer as scattered over the Biirface in the Northwest. It is
being recognized by a number of explorers that there is probably Borne little
difference in origin between the bowlders lying on the Burface and those in the
underlying bowlder clay. In many cases it is impossible that the bowlders
could have been derived by denudation from the bowlder clay beneath ; and
I am rather inclined to suggest the explanation thai those bowlders were
transported in the mass of the glacier itself instead of having been beneath
it. as was the till, ami that as the glacier melted and retired they were dropped
nil the surface. I think that this explanation will fairly account for the
presence "t* most of the solitary local bowlders on the surface of the plains,
where they cannot be accounted for by erosion.

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA

VOL. 1, PP. 411-442; PLS. 6-8

SANDSTONE DIKES

J. S. DILLEli

WASHINGTON

PUBLISHED BY THE SOCIETY

April, 1890

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA

VOL. 1, PP. 411-442, PLS. 6-8 APRIL 21, 1889

SANDSTONE DIKES.

BY J. 8. DILLER.
{Read before the Society December 28, 1890.)

CONTENTS.

Page.
Introduction 411

Distribution of the Sandstone Dikes in Northern California 412

General Kelations 412

Dikes on the North Fork 414

Dikes on Crow Creek 415

Dike on Squaw Creek 416

Dikes on Roaring River 416

Dikes of Poverty Gulch 418

Dikes of Aiken Gulch (Camp Creek) 418

Dikes on Middle Fork 418

Dikes on Dry Creek 420

Dikes of Fight Gulch 42^

Dikes on Salt Creek, etc 423

General Description 424

Mineralogical Composition and Minute Structure 425

Some associated Cretaceous Sandstone Beds 428

Chemical Composition of the Sandstone Dikes and Beds 429

Geologic Relations and Origin of the Sandstone Dikes 430

Position and Age 430

The Dikes occupy Joint Fissures 431

Method of filling the Fissures 432

Phenomena commonly associated with Earthquakes 435

The Region is favorable for the Production of such Phenomena 436

Source of the Sand in the Dikes 436

Origin of the Joints in the Dikes 437

Distribution of the Dikes, considered as Earthquake Phenomena 437

Crosby's Theory of the Origin of parallel Joints 438

Sandstone Dikes observed in other Localities 439

Summary 441

Discussion 442

Introduction.

Several years ago, while studying the Cretaceous shales upon the northwest-
ern border of Sacramento valley in California, I observed in a stream bed
a number of large fragments of sandstone. They were carefully examined
LIV— Bull. Gf.ot.. Soc. Am., Vol. 1, 1889. (41 1 )

.1. S. I'll LEE A.NDSTONE 1'IK I S.

for fossils, in the belief thai the rock from which they were derived was

ajularly interstratified with the Cretaceous shales. Near by I discovered

an excellent exposure of a vertical dike cutting through the bank of tilted

shales from top to bottom, in plain view for a distance of 60 feet. When I

i' ached tin- dike and found it to he composed of sandstone, tin- same I hail

amined for fossils, my interest was thoroughly aroused. A Bandstone dike

tned a paradox. Further Bearcb in that region brought other dikes of

the same nature to light, hut the puzzle was oot investigated until Last

summer, when, with the aid «»i' Mr. .J. Stanley-Brown, a geologic ma]) of the

district was prepared.

Distribution of the Sandstone Dikes in Northern California.

Genera/ h'* /<tti<>ns. — The position of the region containing the dikes is in-
dicated upon the accompanying map, figure l,by the small rectangular area
bounded by heavy lines near the center of the map. The heavy line within
the rectangle shows the general direction of the dikes.

i.i 1 '.• U \p of Northi i ' \ia.

The rectangular nrcn nonr (ho center shows the position >>( the Bandstone dike district, trhioh i-
represented upon ■ larger scale In ti^iir" 2.

\V< -i "i |;, ,i Bluff, California, there La a wide and comparatively low pass
through a pari of the Coast Range between the peaks of Yallo Bally and
Bully Choop to Hay fork of Trinity river. The eastern dope of the pass is

drained by the converging tributaries <'f Cottonw 1 creek, which unite to

form the main stream twenty milee west of the Sacramento.

Across :i base level of erosion, formed by the planing off of the tup of the
Cretaceous shales and sandstones, these streams have cut valleys considerably

DISTRIBUTION OF THE SANDSTONE DIKES.

413

below the general level, and exposed numerous sandstone .dikes. The north-
ernmost exposures of these dikes are along the North fork of Cottonwood
creek ; thence they continue in a belt southwestwardly across Crow and
Squaw creeks, Roaring river, Middle fork, Dry creek, and Salt creek, nearly
to Cold fork, occurring in an elliptical area about eighteen miles long and
six miles in average width.

The distribution of these dikes is illustrated upon the accompanying map,
figure 2. Only those dikes which are 18 inches or more in thickness are

. <t

COAST RANGE
METAMOR PH IC

MORSETOWN & CHICO
CONG.SS.aSHALCS

SANDSTONE DIKES

NEWER FORMATIONS
OF SACRAM.VALLEY

l-y^T^L'-i

Scale of Miles

Figure 2. — Map of the Sandstone Dike District.

Only those dikes which are 18 inches or more in thickness are represented. The serial num-
bers, some of which are omitted, designate localities.

represented. For convenience of reference, the localities of dike exposures
are numbered ; but on account of the small scale of the map some of the

414 J. S, DILLEB — SANDSTONE hlKl-

nuinbers are omitted. Ii is probable also that there are a dumber of undis-
covered dikes doI represented upon the map. The Bhales in the banks of
the streams must be well exposed in cliffi or the dikes they contain will
not outcrop. Along a portion of Squait creek and near the mouth of Middle
fork the banks are so low and covered with soil that dikes, even if they do
occur there, would nol be exposed.

Dikes mi the North Fork. — At 1 ou the map, three-quarters of a mile below
the month of Eagle creek, there is an L8-inch dike of micaceous sandstone
well exposed in a portion of the creek bed and part way up the northern
hank, but upon the southern slope it was not found. The strike of the dike
is N. 15 lv. and the dip 7~>° to the N. W., and of the adjacent sandstones
and .-hales of the fossiliferous Eorsetown beds the strike is about N. 10° W.,
and the dip 15° to the N. E.

The dike is so inconspicuous as a topographic feature that it might be
easily passed by without being discovered, and yet it is sufficiently well
exposed to show its relations clearly. It is the northwesternmost dike of the
region, being four and three-quarters miles from the nearest dike further
down the creek.

( )ne mile above <ia- Point, at 2 on the map, there is a group of six small
dikes, the most important of which are represented in plate 6, figure 3. The
largesl vein is four inches thick and traversed by many cross-fractures which
give it a columnar aspect. The three veins combine as they ascend the
bank, hut soon run out and fail to reach its summit. The small vein upon
the right diminish.- downwards to a mere film, sometimes disappearing alto-
gether, although the joint fissure which it occupies is well developed. Traces
of joints may be seen in the shale to the right of the dikes, and some of them
contain thin films of line micaceous sand exactly like that of the larger
dikes. The plane of stratification in the shales is distinctly marked by vari-
ation in the sediment, as well a- by lines of calcareous nodules, and it ap-
pears that there has been no faulting along the dikes. The boundaries of
\\\<- larger dike- are generally well denned, as are also those of many small
ones, Inn near the tapering edges they are frequently difficult to recognize.

A -hort distance to the I. -ft of the above vein there is another 2-inch vein
which suddenly disappear upwards ; and near by IS the 1-inch vein repre
sented in plate 7. figure 2, traversing a bluff •'!'» feet in height. A few feet

to the right of the dike and parallel with ii i- a well-developed joint. The

dikes are generally vertical, but this one inclines 65 to the N. W., which is
tin- greatest divergence from the vertical position observed. The general
inclination of the shale at this point i- about 15° to the southestward.
Opposite Gas Point, at 3 on the map. tier, i- a I 1-inch dike which is

• All dlraotlom recorded In thU paper are magnetic. The variation f<T thai region I

VOL. 1, 16

FIG. 1— SANDSTONE DIKES ON ROARING RIV'R
1 FOOT AND 6 INCHES THICK.

is**!

,#'V

^-r.;-

FIG 2— GREAT SANDSTONE DIKE ON ROA
RIVER 5 FEET THICK.

FIG. 3. — GROUP OF SANDSTONE DIKES ON NORTH
FORK THE LARGEST 4 INCHES THICK.

FIG 4— LATERAL VIEW OF SANDSTONE Dl
ON DRY CREEK.

DIKES FOUR AND FIVE FEET IN THICKNESS.

415

illustrated in figure 3. Its strike is N. 55° E., and its dip 82° N. W., pene-
trating the Cretaceous shales without faulting or indurating them in the
least. This exposure is of special importance in showing that the dike does
not penetrate the tuff and beds which lie beneath it upon the upturned shales-

Dikes on Crow Creek. — Half a mille above the mouth of Squaw creek, at
4 on the map, is a 4-inch dike exhibiting good joints. Its strike is N. 71°
E. At 5, half a mile further up the stream, there is a well defined vertical
dike 1 foot in width ; strike N. 63° E. Near by is one 7 inches thick. Its
strike is N. 56° E., and with increased width (1 foot) it continues up stream
for several hundred yards.

About 1 1 miles above the mouth of Squaw creek, at 6, is a group of prom-
inent dikes approaching the valley from the northeast. The first is about
2 feet in diameter, and the other three are about half as large. One of these
crossing the little valley enlarges and becomes 4 feet thick, and forms a
prominent, wall-like bluff twenty feet high, shown in plate 7, figure 1.

Fkjure 3. — Section exposi d on the North Fork of Cottonwood Creek at Gas Point.

A 14-inch sandstone dike (9) penetrates the Cretaceous shales (8), which are overlain unconform-
ably by the late formations(l-7) of the Sacramento valley. a=Sluice-box; l = Auriferous gravels of
Red Bluff formation ; 2=Tusean tuff, 3 feet; 3=Clay, 4 feet; 4= Irregular, fine yellowish gravel, 8
feet; 5=Tuff (?) ; 6= Irregular, reddish clay and sand, 12 feet; 7= Ferruginous gravel, sometimes
cemented, 12 feet; 8=Cretaeeous Shales (Chico); 9=Sandstone dike.

The transverse cracks in this dike are parallel to the stratification in the
shale at the right. They so divide the dike into blocks that it resembles
courses of masonry. This resemblance has led many people of the district
to regard the dikes as ancient walls, perhaps of some prehistoric people.
This is the largest exposure of the kind seen in the country, and is well
known for the excellent shade it affords from the hot afternoon sun.

Near by is another dike, 5 feet in thickness. Its strike is N. 40° E., and
it can be traced in that direction across the little vale to the hill a quarter
of a mile away. A short distance northwest of these dikes the valley of

H6 .1. S. DILLEB — SANDSTONE DIKES.

("row creek narrows, and numerous fossils have been found in the conglom-
erate which forms the hills. The conglomerate ie apparently the one which
crosses the North fork jus! below the month of Hulen creek and belongs in
the Chico aeries. All of the dikes, excepting the one already noted on the
North fork three-quarters of a mile below the mouth of Eagle creek, trav-

• Btrata which apparently overlie the Chico con (Ipraerate.

Dike "a Squaw Greek. — At 7, on Squaw creek, there is a 1 1-inch vertical
dike which Btrikes N. 53° E. The direction of Squaw creek and its gentle
Blopes are Buch a- to yield poor exposures of the underlying rocks, and if
other dikes are there they are not easily discovered.

Dikes <>n "Roaring River. —The dike- already noted on the North fork ami
on Crow and Squaw creek- are not clearly related to one another — i. e., the
same dikes cannot he recognized with ahsolute certainty in two valleys. In
a general way it appears that the group of small dikes on the North fork,
one mile above Gas Point, represents the group of large dikes at 6 on Crow
creek, and they have been so drawn upon the map; but their connection has
not been traced, nor can it be easily on account of the soil on the broad
divide between.

< )n Roaring river, however, lic/ms a series of dikes which can he traced
for a considerable distance. One of the number, which will he called the
Great Dike, can he recognized for aboui '■>'. miles. Itislir-t seen at 8, three-
quarters of a mile above the mouth of Roaring river, on the left hank of the
stream, with a thickness of 20 inches. Section 2539 is from this dike. Its
position was vertical and parallel to the wall. Section 2540 was vertical
and transverse, and 2541 was horizontal. The strike is N. 7<>° E., parallel
to the gen >ral direction of the valley up which it continues for over a mile.

Three-fourths of a mile above the first exposure the same dike crop- out
again near the west end of Mr. Drew's fields. It stands out prominently,
as Bhown in plate 6, figure 2. The strike of this roughly columnar, wall-
like mass i- N. 55 E. It is vertical, and 5 feet in thickness. The rock is
micaceous, and although hard, is rather easily disintegrated; for this reason

the rock crop-; out OH sleep slopes, where the erosion is rapid and in 8XCI 38

of complete disintegration ; but on gentjer slopes, where the disintegration
is in excess of transportation,! he dikes do not outcrop and cannot be readily

traced. The -oft -hah- are here well exposed directly against the dike, and
-how no trace of induration. The sides of the dike are somewhat firmer
and the -and apparently liner than that in the middle portion. This feature

has been noticed in a number of cases, and will be referred to again in con-
sidering the micr08C0pic Btructure of the rock. It recall- similar phenomena
frequently observed in connection with dikes of igi us rock-. The simi-
larity i- enhanced by the fact that along it- b irders the dike frequently in-
clude- -mall fragments of -hale a feature which ha- been observed in many

FiG 1 — LATERAL VIEW OF WALL-LIKE SANDSTONE DIKE ON CROW CREEK. 20 FEET HIGH.

5W|

- ->* niMgi

FlG 2 -SANDSTONE DIKE FILLING A JOINT
ON NORTH FORK. 4 INCHES THICK.

FlG 3 — SANDSTONE DiKE WITH PARALLEL AN
TRANSVERSE JOINTS ON DRY CREEK.
18 INCHES THICK.

THE GREAT DIKE. 417

other dikes. Although the fractures are nearly all transverse, cutting the
dike into irregular blocks or columns, there are a few fractures near the
edge of the dike parallel to its sides.

Fifty yards west of the large dike here exposed are the two small ones
shown in plate 6, figure 1. The larger one on the left is a foot in diameter,
and has well-developed parallel jointing. An important relation of the
principal set of transverse joints to the bedding in the shale is well illustrated
in these dikes, where it is seen that the stratification and the most con-
spicuous cross-jointing are parallel. Specimens 1971 and 2384 from the
middle portion of the Great dike are apparently coarser grained ; 1970,
2385, and 2386 are from the more compact and apparently finer-grained
border. Specimen 2387 is from a little dike close by the great one, and
2388, 2389, and 2390 are from the two dikes 50 feet away.

The Great dike continues southwest across a bend of the stream, and is
well exposed at 10, where plate 8 represents its appearauce. It is here 5
feet in greatest width, and divides downwards into a number of smaller dikes.
The finer-grained and somewhat harder edges of the mass and its cross-
fractures are here well exposed. Within the shadow in the central portion
of the dike there is an inclusion of shale. This included shale is soft and
spheroidally weathered, exactly like that upon the sides of the sandstone
dike. Scarcely a trace of jointing can be detected in the adjacent shales at
this point, but at a few other localities it has been observed in connection
Avith the dikes. The direction of the bluff here is such that the shales appear
to be horizontal, but in reality they are slightly inclined. Specimen 2391
is from the lower portion of this dike, and 2392 from the included shale.
Near this exposure the shales strike N. 10° E. and dip 17° to the eastward.

Continuing southwestward, the Great dike crosses another elbow of the
stream and is again exposed at 11, in an abandoned placer mine, where it
is 3 feet thick. Its dip is 82° S. E. and its strike N. 48° E., which carries
it across the divide to Poverty gulch near Mr. Glass's, 2 miles away, where
it again appears. Associated with it at 10, on Roaring river, are several
smaller dikes. One is 6 inches thick ; strike N. 47° E. Another is 1 foot
through, and dips 77° N. W. A third is only 2 inches in thickness. Dis-
tinct traces of joints are developed here, and their strikes and dips are the
same as those of the dikes ; furthermore, they appear to occur in the neigh-
borhood of the dikes only. In fact, some of the joint-cracks which escape
sight at a first hasty glance, when examined more carefully are found to be
filled with sand in all respects like that of the larger dikes with which they
are associated. Chips may with difficulty be obtained showing one of these
miniature dikes, but generally the intruded sand of the dikes separates very
easily from the adjacent shales, and thin sections of the contact cannot be
obtained.

118 .1. s. DILLER INDSTONE DIKES.

Dikes of Poverty Gulch. — Poverty gulch is the next one in which the dikes
are exposed south of Roaring river. A group of them crosses the gulch at
12. oue ami one-fourth miles above its mouth mar Mr. Glass's. The largest
is 20 inches in width, five average from •"> to •"> inches, and Beveral are about
2 inches across. They are vertical, strike N. 13° E., directly in line with the
I rreat dike just noted on 1 {oaring river, and apparently a continuation of it.

Dikes of Aiken Ghilch (Camp Creel). — The first dike seen Dear the mouth
of Aiken gulch is the Great dike traced from I {oaring river. Here it i- 5
feet in width, vertical, with strike N. 40° E. The northwestern wall is some-
what irregular. Bending small tongues out into the shale, and numerous
fragments of the shale are included in the dike. Generally, however, the
walls of the dike are sharp, well defined, and smooth, and are well exposed
from top to bottom of the bank, forty feet high. The edges here, as in many
ofthe other dikes, are apparently somewhat liner (e. </.. specimen 2393 > than
the middle portion (specimen 2-7.M .

At 14 is a dike 8 inches in thickness, and at 1">, on the north bank ofthe
gulch, quarter of a mile above its mouth, there are six small dikes, ranging
generally from 2 to 12 inches thick. One of the number increases rather
suddenly to a width of 3 feet, but may not continue so large. They strike
N. 40° E. Near them a number of joints are exposed, and they are exactly
parallel to the dikes. A shorl distance further up the stream bed, on the
south bank, one ofthe dikes forms a good, wall-like exposure.

Dikes of Middle Fork. — Ascending Middle fork, the first dike encountered
is a short distance above the mouth of Aiken gulch, where the (Jreat dike
appears in the northwest bank at 16. At 17 two 6-inch dikes cross the
creek. At 18, near Miller's, the Great dike again crops out, crosses the
stream, and forms a heavy wall upon the left, bank. It ranges from 3 to ."»
feet in thickness, strikes X. 12 E., and is cross-jointed, weathering out in
large, round bowlders. Nearby, upon the northwest side of the ( Jreat dike.
are two small dikes, 2 and 4 inches in thickness ; and upon the opposite side
i- another, 1 foot through. Joints appear in the shahs parallel to these dikes
where they cross the creek. A few hundred yards south of Miller's, on the

trail leading over to .John Allen'-, on Dry creek, a 1 1-inch dike is exposed.

On the left bank of the stream the Great dike continues southweetward
across a curve, reaching tic stream again three-quarters of a mile above
Miller's, w here i he greatest width of the dike, 8 feci, wa- observed. At this
point the jointing in the dike is less regular than usual, and very small frag-
ments of -hale are included in it. These fragments are small and flat and
are arranged with the scales of biotite parallel with the sides of the dike.

I pon the weathered BUrface |||,. -hale j'ra- nt- fall away and produce

-mall pit-. Near the middle the vein is somewhat banded. Here and there
are -mall veins of calcite. Although it i- well exposed upon the right bank

BULL. GEOL. SOC. AM.

VOL 1, 1839, PL

GREAT SANDSTONE DIKE ON ROARING RIVER. 5 FEET THICK.

EXTENSION OP THE GREAT DIKE. 419

of the stream, it does not continue all the way across, but is cut off by shales
which crop out directly in front of the dike. Whether or not the dike was
offset to one side I could not discover. Specimen 2531 was collected here.

About 300 yards northwest of the line of the Great dike, at 21, a mile
above Miller's, a 5-foot dike is well exposed; strike N. 41° E. It includes
numerous fragments of shale, some of which are several inches across.
Two small quartz pebbles were found in this dike, but otherwise the dike
material was like that in all the other dikes. The fragments of shale were
not distinctly oriented in the dike and gave a prominent pitting to the weath-
ered surface. Within fifty feet to the northwestward are three other dikes,
ranging from 4 to 5 inches in thickness.

Above Miller's a mile and a quarter, Middle fork passes through a small
narrows between ledges of conglomerate. At the irrigating dam just below
the narrows the micaceous sandstone (specimens 2532 and 2533) interstrati-
fied with the shales and conglomerates looks very like the rocks found in the
dikes. It is well exposed in a side gulch, and strikes N. 24° W., dipping 32°
to the N. E. The strike and dip are not uniform here, for the conglomer-
ate by the narrows strikes N. 37° E. and dips 47° 8. E. , and at another place
near by the shales strikes N. 5° E. and dip 33° S. E.

Above the narrows, at 22, on the right bank of the stream, are three
vertical dikes, 14 inches, 2 feet, and 3 feet, respectively, in thickness. The
last apparently represents the Great dike with which it is in line, striking
X. 40° E.

At 23 two other dikes appear, one of 2 feet and the other of 15 inches
with offsets to the northwest as it asceuds. At 24 is a 12-inch dike exposed
in the bed of the stream; strike N. 39° E. A little further up Middle fork
a gulch enters from the south, and in it (at 25) this dike crops out a second
time with a thickness of 6 inches.

On the opposite side of the stream, at 20, is a rather heavy dike, which can
be traced for 300 yards aud appears to be the continuation of the Great
dike. It crops out again at 27, where it is 2\ feet thick and strikes N. 45°
E. Continuing to 28, it disappears in the south bank with a thickness of 1
foot. From this point to its most northeastern exposure on Roaring river is
about 6 miles, in which distance there are 15 exposures of the Great dike.
It may not be a continuous dike all the way. More likely it is a series of
dikes very nearly in the same line.

At 27, on the southern side of the Great dike, is a small one 14 inches in
diameter. Where next exposed further up the stream it is of somewhat
smaller size.

At 29 are three small dikes, one of which is 6 inches and the others 2 inches
each in thickness. These are followed by two 4-inch dikes at 30 ; and again
at 31, about 4 miles above Miller's, by one 2 feet in diameter.

LV— Bum,. Gf.oi,. Soc. Am.. Vol. 1, 1889.

1:20 J. S. DILLEB I.NDSTONE DIKES.

At 32 a L-fool dike cuts a bluff of conglomerate. Its strike is N. 38° E.,
and on ascending it offsets to the northwest. At 33 are two dikes, one 14
inches and the other 6 inches through, while the dike at -'54 has a diameter
of 16 inches. At 35 a 12-inch dike appears and continues through three
exposures, the last one at 36.

The linal dike of the series on Middle fork occurs at 37, just below the
cabin of J. ( '. Crow, two and one-quarter miles below the road crossing, and
is 1 foot in diameter. The search for <lik<- was continued over three miles
further up Middle fork, but none were found.

Dikes on l)nj < 'reek. — On Dry creek more than twenty dikes are exposed —
a larger number than on any other stream, and they arc scattered over a
considerable distance.

Just below the road crossing of I >ry creek, one and one-fourth miles above
the mouth of Salt creek, on the north hank of the stream, are four dikes
occurring at intervals for several hundred yards. The easternmost varies
in width from 14 inches below to only a few inches above. As it rises
through the shale bank twenty-five feet in height, it offsets several times to
the eastward. Near the base of the cliff there i< an offset of live feet, but
the two parts are partially connected. The shale- and sandstone beds at
this point strike N. 29 W. and dip 24° N. E. The rock of the dike is a
fine-grained sandstone, containing some mica and fragments of shale.

The next vein, three hundred feet from the first, is about a foot in thick-
ness and strikes N. 13 E., with a slight dip to the N. \\\ It is wider below
than above, where it cuts a number of very distinct Bandstone Layers without
faulting.

The third vein is onlv * inches through, and strikes N. 33° E., dips 85
N. W. It is very compact and onsets, as do its neighbors, to the Bouth-
i astward.

The fourth dike varies greatly in width, from 14 inches below to •"> inches
in the middle, and then widens, with offsets, to 1 fool above.

At 39, by the road in the stream bed, is a 20-inch dike exposed for over one

hundred feet. It IS very regular, has laminated sides, and the middle por-
tion, as in nearly all the other dikes, is broken into approximately rectan-
gular blocks by the cross-fractures.

A short distance above the road a prominent dike appears on the south

I right) bank. It is only a foot thick but very Like a wall, as may hi seen

in the accompanying illustration, plate 6, figure I, where a lateral view brings
out the cross-fractures very distinctly. It will be seen thai the transverse
joints are arranged in systems. All those of the same system are approxi-
mately parallel and cut across those of other systems in a manner quite un-
like the columnar jointing in dikes of igneous rocks. The greater number
of the cross-joints in this dike are horizontal, but a number are apparently
parallel to the beds of shale in the adjacent exposure.

IRREGULAR SANDSTONE DIKES.

421

Near by are five small dikes, each only a few inches in diameter, and
varying considerably in strike — from N. 35° E. to N. 55° E. Ascending the
stream, two small dikes, 2 and 3 inches thick, are seen at 40, two miles above
the mouth of Salt creek, on the left bank ; then follows a stretch of three-
quarters of a mile in which none were seen.

At 41, about one-quarter of a mile below John Allen's, headquarters of
the Diamond Range, three excellent dikes appear. The first is 18 inches in
width, has a strike of N. 40° E. and dips 85° N. W. It is represented in
plate 7, figure 3, which shows distinctly two sets of fractures common in these
dikes: (1) Cross-fractures dividing the mass horizontally and vertically into

i *

Figure 4. — Crooked Sandstone Dike, is Inches In Thickness.
On Dry creek, five and one-half miles above the mouth of Salt creek. 1 = Dike ; 2 = Shale.

more or less regular 6-sided blocks; and (2) divisional planes parallel to the
.sides of the dike, separating it into thin plates. The shales here as else-
where are neither altered nor disturbed near the contact. Specimen 2404
was collected from the edge and 2405 from the middle of this dike.

Near by is another dike of the same size and position, which is especially
remarkable on account of* its distinct vertical banding parallel to its sides.
Similar banding has been seen in other dikes, but nowhere else so distinctly.
The banding is due to the parallel arrangement of coarser and finer sand,

122 .1. tf. DILLEB — SANDSTONE DIKES

:ui<1 the mica plates in them are all arranged parallel to the banding. Hand
specimen '2h"i shows the banding plainly. Section 2407 is from an appar-
ently coarser portion in the middle. Sere, too, are well seen the ripple-like
mark- upon the outer face of the dike. They have been seen elsewhere.
especially al Js. on Salt creek, and will be referred to again. Near the
same place may be Been a small dike offsetting mice to the eastward. The
offsetting portions are not visibly connected.

Continuing up the stream, a 14-inch vein and several smaller ones may
be observed before reaching John Allen'.-, three miles above the mouth of
of Salt creek, At this point 12) Beveral dikes occur in the left bank of the
stream. One dike is <> and another 4 inches in diameter, and these may he
seen again a short distance to the uortheasl in Horse gulch, which opens into
Dry creek at Allen's. One of these dikes, with a very small one near it, is
displaced above to the eastward. Hen-, also, three small veins combine as
they ascend and form a larger one.

One-fourth of a mile above John Allen- is a L4-iuch dike, which in a
high hank cuts fit'ty feet of exposed -hale and can be traced across the bed
of the stream and into the field for several hundred yards. Specimen 1963
i- from this dike. Near by are several other small dike-.

At 44, five and a half miles above the mouth of Salt creek, two prominent
dikes are exposed in the left hank of the stream. One is 18 inches in thick-
ness ami quite irregular, a- shown in 6g. I. An offset occurs in the dike
near the base ot' the bluff, and it contains fragments of -hale. This dike
appear- to he approximately in line wjth the Great dike, which was la-t seen
on Middle fork. With this extension the Great dike has a total length of
about '.i.1; mile-.

A few yards up si ream another dike occurs, 1 ■'! inches in thickness : strike
\. :;i E. ; dip 75 N. W. Near its edge tin- dike contains numerous frag-
ments of shale. Specimen 2400 contain.- fragments of the shale, and specimen
2401 is from the middle of the dike. Several small dikes have been ob-
served further up Dry creek. They are marly in line with some of those
exposed on Middle fork ami Berve to join all the dikes together in one large
group.

Dikes of Fight Gulch. — South of Dry creek, the dike- are oexl exposed
in Fight gulch, which open- from the northwestward into Salt creek about

two and a half mile.- above it- mouth. At I"), a 2-foot vertical dike occur-,
with a -t like of N. 38 E. The 'like rock contains a few fragments of -hale.

and is full of mica which lie- parallel to the sides of the dike. The sides of

tie' dike have ripple-like marks which are nearly horizontal.

< >ne hundred yards further down the gulch is a dike 3 feet in thickness,

full of mica a- the other, ami with tie- -ame strike. \. \t comes a 15 inch
dike ; .-Hike N. 15 E. It i- W'll joiuted, ami ha a -mall parallel dike close

VERTICAL STRUCTURE IN THE DIKES. 423

upon one side. At 46 is a 6-inch dike, which is very lamellar, splitting
parallel to the sides of the dike. Section 2524 from this dike is vertical and
transverse, 2525 is horizontal, and 252(3 is vertical and parallel to the sides
of the dike. A 2-inch dike near by contains but little mica, aud that not
distinctly oriented ; but in the next dike, near 47, mica is more abundant
and distinctly arranged parallel to the sides of the dike. This dike is 20
inches through, and like a number of others is without any ripple-like
marks upon its sides. Near by is a 2-inch dike; and three hundred yards
further down the gulch a 15-inch dike occurs which is very soft and rotten,
showing spheroidal weathering.

About a quarter of a mile above the mouth of the gulch the last dike was
seen. It is 1 foot thick, very soft, crumbles in the hand, and is full of mica
arranged parallel to the sides of the dike. Near by is an exposure of two
small dikes in joints. One terminates upwards and the other downwards
where the joints end.

Dikes on Salt Creek, etc. — To the southward the number of dikes "gradually
decreases. Ten are exposed on Fight gulch, but on Salt creek there are
scarcely half a dozen. At 48, four miles above the mouth of the creek, the
largest occurs. It is 3 feet in diameter, strike N. 40° E., stands vertical, and
is exposed for 60 feet. Specimen 2519 was collected here, parallel to the
sides of the dike, and section 2520, perpendicular. The scales of mica which
it contains are arranged parallel to the sides of the dike. It is somewhat
banded vertically, and its sides are rippled parallel to the line of contact
with the bedding planes in the adjoining shales. The ripples are about an
inch in width ; their crests are somewhat rough, while the intervening portions
are smooth.

Three hundred yards down the creek, at 49, is another dike, 21 feet thick,
containing an abundance of mica scales arranged parallel to its sides. The
strike of the dike is N. 35° E., parallel with the course of the stream at
this joint, and it is exposed at several places, showiug apparently a promi-
nent offset to the eastward. A small dike near the large one sends several
lateral projections into the adjoining shales. At 50 an l<S-iuch dike appears,
and can be traced down the creek for quarter of a mile. The ripples on
the sides of the dike run vertically. Upon its northwestern side is another,
about 4 inches in diameter.

At 51, opposite McNett's, a 1-foot dike appears ; strike, N. 40° E. It is
much fractured, showing no tendency whatever to break into regular forms.

A fourth of a mile below McNett's the shales are much disturbed, and
here two small dikes occur. One of these, traversing a thin sandstone, ends
above aud is apparently cut off below. The other, a 6-inch dike, which
splits easily into thin plates, appears somewhat as if displaced with the
shales.

12 1 .1. S. DILLEB — SANDSTONE DIKES

At 53, two and two-thirds miles above the mouth of Sail creek, is a dike
1 fool in thickness. Section 2522 from this dike was parallel with the side,
and 2523 was vertical and transverse. At this point the shales disappear
beneath the newer formations, and nothing more is seen of the dikes further
doM ti the stream.

The section so well exposed along Cold fork was examined, hut no dikes
were discovered. They do not extend so far southwest. It is likely that a
few may appear in Long gulch, which my limited tim< did nol enable me to
explore.

The most southwestern dike observed was seen on the Red Bluff* and Hay
Fork stage road, about four miles northwest of Shiveley's I Hunter's 1*. I ). i.
The dike is 2 feet in thickness, rather soft, strikes N\38c E., and its southerly
extension is offset to the northwest after the maimer of the dikes on Salt
creek.

General Description.

The dikes are nearly vertical, wall-like masses of sandstone, varying from a
mere film to 8 feet in thickness, and cut directly through the inclined strata —
sandstones and shale- — of the Cretaceous group. They vary somewhat in
strike from N. 20° E. in the southwestern portion of the series to N. 70° E.
near the other end ; and in dip arc usually vertical, but they may be in-
clined as much as 65° to the N. W.

The great majority of them are less than a mile in length, some perhaps
less than 100 yards; hut the Great dike, which extends from near the mouth
of Roaring river across Poverty gulch, Camp creek, and Middle fork appar-
ently to Dry creek, has a total Length of 91 miles. At one point on Middle
fork it is * feet thick, but generally about o feet.

The dikes are parallel to the joints in their vicinity, and BO related to them
as to indicate thai the joints have nol been produced by the dikes, but that,
on the contrary, the position of the dikes has been determined by the joints.

The majority of the dikes observed are Btraight, intersecting a Btream-

blull' from top to bottom, affording an exposure ranging from live to sixtv

feet in height. By offsetting a Bhorl distance to one side or the other, the
dike sometimes exhibits a more or less zigzag course both vertically and
horizontally. Others appear to end abruptly before reaching the Burface,
< asea have been Been also where a dike apparently ended in its downward
course, but Buch have always been found connected with other dikes. In a
number of cases dikes have beeu noticed to combine as thej ascend, but no

examples of combining in tl pposite direction were discovered.

The shales and sandstones in contact with the dikes are not disturbed by
them nor indurated in any «:iv as if by heat, which is frequently the case
upon the borders of igneous dik< -.

GENERAL CHARACTERS OP SANDSTONE DIKES. 425

The dike rocks frequently contain fragments of shale. They are generally
small, but occasionally as large as a* hand and rarely larger. The shale
fragments are usually flat and arranged with the scales of mica parallel to
the sides of the dike, but this is not always so, for they may be thick, angular,
and without orderly arraugement.

A common phenomenon which, however, is not universal is that the sides
of the dike are more solid and apparently also of finer sand than the middle
portion. Occasionally, too, the dikes are distinctly banded near the edges,
and this banding is found to be due to streaks of finer and coarser sand ; but
it is not a conspicuous phenomenon. It may, however, be distinctly seen in
a hand specimen of the rock at a distance of twenty feet.

A more important feature, and one which will be noticed more fully at
another place, is the arrangement of the scales of mica in the dike parallel
to its sides. In a few cases the mica scales had no definite position, but
generally they are arranged as indicated and give to the rock a direction of
easiest cleavage.

The dikes have two sets of fractures, one transverse and the other parallel.
The transverse fractures divide the mass into more or less regular six-sided
blocks, giving the dike a rudely columnar appearance. It is generally true,
also, that the most abundant set of cross-joints is parallel to the stratifica-
tion of the adjoining shales. The other joints, which are parallel to the sides
of the dike, may be absent, and when present are usually most abundant
close to the border of the dike, imparting to it a lamellar structure.

MlNERALOGICAL COMPOSITION AND MlNUTE STRUCTURE.

These dike rocks are wonderfully uniform in physical properties and
composition throughout their whole extent. Upon a fresh fracture the color-
is gray, varying slightly in shade, but when weathered it is yellowish, owing
to the presence of iron oxide.

Biotite appears to be always present, and generally in considerable quan-
tities, so that it is one of the first minerals recognized when examining the
hand specimen, but is not so abundant as to make the rock conspicuously
micaceous. The rock is too fine grained to allow a further determination of
the constituent minerals without the aid of a microscope.

In the thin section the rock is seen to be composed largely of quartz, feld-
spar, and biotite, with considerable calcite cement. Serpentine, titanite,
magnetite, and zircon are less common, and other minerals are rare. Besides
the fragments of simple minerals, there are numerous composite grains
derived from metamorphic rocks.

The grains of quartz are usually far more a'bundant than any other kind,
and constitute on an average (roughly estimated) about 40 per cent, of the
whole rock. They are commonly angular, and rarely well rounded. In

l-v,

.1. S. MI.IKi: — SANDSTONE DIKES.

the latter case they sometimes contain glass inclusions, showing that the
grains are quartz phenocrysts derived from an eruptive rock, and may
have been made round in the original mass. The angular grains not in-
frequently contain the minute, dark needles commonly found in the quartz
nf' granitic rocks, [nclusions of magnetite, biotite, and zircon have also
been noticed.

Both strial id and unstriated feldspar are present : sometimes they are in
about equal proportions, l»ur generally the plagioclase is most abundant.

<-»--iA^\

.-v,

Fioork 5.

Km. i in: G.

I i.i i:i 7.

I--i,.i it i . -Mot ' Vital movent nt ■■< th< m to pro-

tht folia.

Fioi i:i •■. — /■ ird '• nt of tin

I ■ i p< i /•< n I Hon.

'I'lip biotite represented in figu tnd7 ir mewhat leas than half a millimeter

in length.

1 I casionally the feldspar is much altered. Inn elsewhere it is clear with but
Blight trace of alteration, and between crossed Nicola shows twinning bands
very distinctly. Like tin- quartz, tie- grains of feldspar are angular and
Bhow hnt little nt' tin- alna.-iiiii consequent upon beach action for a long time
nr t ransportat ion for a long distam

ARRANGEMENT OF MICA IN THE DIKES. 427

The biotite is in irregular scales, often much tattered and torn in the
process of transportation. As has been already noted, it is usually arranged
parallel to the sides of the dikes. The scales stand on edge evidently — a
position which they did not assume under the influence of gravity alone.
Thin sections of the dike rock have been prepared in three directions at
right angles to one another. One section was made parallel to the side of
the dike; the others transverse to it, both vertical and horizontal. The sec-
tions parallel to the sides of the dike show no conspicuous arrangement of
the particles, but the scales of mica are all seen broadside. In the trans-
verse sections, both horizontal and vertical, the biotite is seen edgewise,
appearing in narrow strips which are strongly pleochloric and full of cleav-
age lines. In the vertical transverse section the alignment of the mica scales
conies out most conspicuously, and in this it may be seen that all the other
mineral fragments in which one diameter is decidedly larger than the others
have their longest diameters all parallel — an arrangement which may at once
recall the fluidal arrangement of feldspar and other minerals commonly ob-
served in eruptive igneous rocks.

Some of the scales of mica have been crushed edgewise in such a manner
as to cause the folia to separate and form small cavities which have since
been filled with calcite, the chief cementing substance of the rock. This
peculiarity of the mica scales is represented in figure 5. It shows that there
was motion in at least one of two directions, but does not distinguish between
them. In other cases, however, there is evidence tending to show more defi-
nitely the direction of motion in the sand. In figure 6 a scale of mica
is represented in which the folia upon the left side of the scale have been
crumpled by the movement of impinging grains of sand. The right-hand
portion of the scale has not been crumpled, and the relations of the various
parts of the scale suggest that the direction of motion was from below
upwards.

The scales of biotite in the dike i*ock are apparently identical in every
way with those in the dioritic rock which is exposed northeast of Ono and
forms so large a part of Bally and the Trinity mountains. This view is sus-
tained by the presence in section 1987 of a grain of diorite in which the
plagioclase feldspar and biotite are well represented.

Much of the quartz, as already remarked, comes from a similar source,
and so may the feldspar ; but there are many grains of a different charac-
ter. There are grains of serpentine and other rocks which are distinctly
metamorphic, like some of those of the Coast range. The commonest grains
are composed chiefly of fine aggregate quartz in which thei*e are minute
black particles, often arranged in irregular patches or streaks. They are
rarely clear and transparent, but frequently nearly so where microscopic
veins of aggregate quartz cut across the larger grains. This sort of mate-
rial forms a considerable portion of the rock, occurring not only in the form

L VI— Bull. Geol. Son. Am., Vol. 1, 1889.

428 J. S. DILLEB AM'-MNi: DIKES.

of distinct grains, but also aa finer material mingled with the cement in the
interstices of the larger grains in such a way as to suggest at times that it
is a part of the cement and deposited since the formation <>f the dikes. As
there are no quartz veins found about the dik* - pting the extremely

minute ones which traverse in each case only a single grain of sand such as
is derived from metamorphic rocks, it is believed that the dike rocks have
not received dep - - if silica from solution in circulating waters. The
tenting Bubstance of the rock is carbonate of lime, which is abundant in
the adjacent shale- and forms larger or smaller parts of all the sandstone
dikes, occasionally occurring as small veins. Grains of eruptive rocks are
very rarely observed. In section 2378 i- a fragment of hornblende andesite.

Some associated Cretaceous Sandstone Beds.

Some of the fine-grained sandstones clearly interstratified with the shales
of the Horsetown and Chico beds contain Bcales of mica, and in nearly every
respect excepting mode of occurrence so closely resemble the dike rocks that
hand specimeus of the two cannot be readily distinguished without the aid
of a microscope, and even then it is often impossible. Such saudstoni
are, however, not common. They have been observed on Byron creek at
the top of the cascade, half a mile above Ono. Their strike is X. 10° E.,
dip 20 S. E. Specimen- 2548, parallel to the bedding, and 2549, perpen-
dicular to it, were collected here. They occur also two miles north of' Ono,
on the road to [go, where the rock i- very micaceous and rests directly upon
the dioritic rock from which it has been derived ; strike X. 40° E., dip 22
S. E. Specimen 1991 wa- collected at this locality.

Similar rocks were observed at the .lam on .Middle fork, where specimens
2532, parallel, and 2533, perpendicular to the bedding, were collected. The
>trike b ff.24 W.. and dip 32 X. E. <)u Dry creek, 3 miles above A.
Allen'-, specimen 251 1 was found. Such rock- occur also on Salt creek,
half a mile above Martin'.-, with a strike of N. 30 to 37 W., and dip 2
to 30 N. E. Specimen 2517 was collected at this locality. The last local
itv t'» !"■ mentioned is on Middle fork, a mile above its mouth, where speci-
men 2537, which is quite full of mica, wa- found.

The locality last named i- to the eastward of any of the dikes, ami

atigraphically above them. The beds on Salt creek and at the dam on
Middle fork are penetrate. 1 by the dikes apparently without change, but
those of the other localities which lie northwest of the .lik.- area dip easterly
toward- the dikes and may possibly reach them at considerable depths be-
neath th( surface.

The mineralogical composition and structure of all th< -.■ sandstone bed- is

essentially the same. In composition, al-o, they n semblc the sandstone dikes,

but in minute structure they difier in an important respect: tn the sandstone

ARRANGEMENT OP MICA IN THE BEDS.

429

beds as in the dikes, the mineral fragments lie with their long diameters
parallel ; furthermore, they are in the bedding plane. The scales of mica
are all parallel, and when viewed edgewise, in general arrangement they
look like those in the sandstone dikes ; yet there is an important difference .
Their parallel arrangement in the two cases is the result of very unlike con-
ditions. The particles of sand, subsiding under the influence of gravity
alone, lie upon their flat sides, and in this manner all become parallel in the
sandstone bed and lie in the plane of stratification. A large particle of
mica at first straight lies horizontal, stretching perhaps over several grains of
other mineral. Other grains in turn fall upon it, and being pressed down
by accumulating sand above, indent or bend the mica and make it conform
to the irregular outlines of the adjacent grains as in figure 7. In sediment-
ary rocks, where the scales of mica are crushed in the process of deposition in
water, the crushing takes place perpendicular to the plane of foliation in the
mica, and does not ordinarily produce openings between the folia ; but in
the sandstone dikes the mica was crushed parallel to the plane of foliation
as represented in figures 5 and 6.

Chemical Composition of the Sandstone Dikes and Beds.

Chemical analyses have been made of five specimens of sandstone from
dikes which are widely separated and equally distributed throughout the
field. The results are as follows :

Chemical Analy

ses of Sandstone

Dikes and Beds.

Number of

■ >

3.*

4.*

5."

8.*

analysis.

SiO, . . .

48.13

48.10

59.10

01.60

54.55

55.85

67.62

60.74

TiO, . . .

.24

.47

.70

trace

.76

.48

.86

P205 . . .

.14

.13

trace

.08

.10

.18

.08

trace

Al.,03 . .

11.19

12.16

14.02

12.15

10.64

13.20

13.63

10.25

F.-,();i. . .

1.25

1.02

3.16

2.09

1.59

2.56

1.25

4.31

FeO . . .

1.47

2.14

1.42

3.30

1.16

4.77

3.27

6.21

MnO . . .

.29

.26

trace

1.53

.24

.15

trace

(JaO . . .

16.39

15.88

9.35

6.92

14.30

6.93

2.80

4.97

BaO . . .

.04

undet.

. ■

■ ■ ■

undet.

.03

• < •

MgO . . .

2.22

1.65

1.72

2.33

1.29

1.90

2.34

3.69

Li,0 . . .

none

K„0 . . .

1.17

1.56

1.49

1.41

1.68

1.89

1.11

.52

Na.,0 . . .

2.29

2.46

2.21

2.16

2.60

2.78

1.83

CO., . . .

12.73

10.36

4.65

5.05

9.05

4.97

.72

2.29

SO, . . .

trace

.27

.10

...

.40

CI. . . .

trace

.09

trace

H20 at 110°.

.78

.46

•

1.13

.64

" red heat .

1.78
100.11

3.27

2.63

3.10

1.60

2.29

2.83

4.36

99.92

100.4--)

100.46

100.28

09.97

99.73

100.43

* The material of Nos. 3, 4, 5, and 8 was dried at 101° C.

ity

50.

t •

11.

> •

12.
21.

130 .1. S. MI.I.Kl; ANDSTONE DIKJ -

Description <>{ Specinn m.

No. 1. Sandstone dike on Sail creek, \ mile above McNett's.
*_'. '■ 1 i miles below Ono bridge, on North

fork of ( lottonwood.
•">. '• | mile below John Allen's, on Dry

creek.

i n .. .. .. .. it

al John Allen'.-, on Dry creek.
6. bed at dam on Middle fork, 1 mile above

Miller's.
i. top of cascade, 3 mile up Byron creek

from ( >no.
•s. " 21 mile> above Johb Allen'.-, on Dry

creek. " 44.

Of the foregoing analyses numbers 1. 2, 6, and 7 were kindly made for me
by Mr. Thomas M. Cbatard, and numbers ■">. I, 5, and * by Mr. J. Edward
Whitfield, in the chemical laboratory of the I.'. 8. Geological Survey.

The range of silica in the dike rocks is from 18.10 to 61.60, while in the bed
rock it is from 55.85 to 67.62, with a considerably higher average amount
than in the dike rock-. The same is true to some extent of the oxides of
iron. These are fully counterbalanced by the lime and carbon dioxide,
which shows that the lime carbonate is more abundant in the dikes than in
the beds— a fact which is apparent also under the microscope. The carbon-
ate of lime i- the ,•<• nt ami. being a .-< idary deposit, should not he con-
sidered a constituent of the original sand. It bas already been shown that
in mineralogical composition the dikes ami certain bed rocks are practically
identical, and the chemical analyses illustrate the same fact

Geologic Relations \m> Origis of the Sandstone Dikee

Position "a 'I Age. -From the geologic map, figure 2, in which the distribu-
tion of the .like- is shown, il will he -ecu thai they are confined to the
Cretaceous Horsetown and Chico beds. Figure 8 is a cro — ectionofthe
same region, ami shows in a general way the relations of the rock- from

Bully Choop in the Coast Rang i the northwest, to the Sacramento valley

on the southeast. Thej arc naturally separated into four groups of for-
mations: i 1 fhc Metamorphic rocks of the Coast Range; (2) the Cretaceous
formations of the Bald hills, which arc marked by an old base level of erosion
and composed of conglomerates, sandstones, and -hale-; of tic Horsetown
, and Chico beds ; (3) the sandstone dike- which penetrate these beds; ami
I i the tuff, gravels, sands, and clays of the newer formations which lie in
the Sacramento vallev.

STKATIGFvAPHY OF THK DIKE REGION.

431

The Cretaceous group of strata appears to be a continuous, conformable
series, thousands of feet in thickness. The basal bed, well exposed on Eagle,
Byron, and Jerusalem creeks, is a heavy conglomerate of coarse, round and
sub-angular fragments derived directly from the older metamorphic rocks,
upon which it rests unconformably, and marks approximately an ancient
shore line of Cretaceous time.

The strata of the lower portion of the group lyiug on the North fork of
Cottonwood creek above the mouth of Hulen creek contains an abundance
and great variety of fossils, regarded by the California Geological Survey
and Dr. C. A. White as belonging either wholly or in large part to the
Horsetown beds. At the mouth of Hulen creek the Chico beds, characterized
by many fossils, occur and extend eastward, passing beneath the later for-

Consl K.mgc

r&menlo Valley

Figure 8.— Section across the Dike Region along the North Fork of Cottonwood Creek, in Shasta

County, California.

l=Metamorphic and dioritic rocks of the Coast Range ; 2=Cretaceous conglomerates, sandstones,
and shales; 3=Sandstone dikes; 4=Newer formations of the Sacramento valley. There may be
an unconformity near the middle of the section.

mations of the Sacramento valley. Near the western limit of the newer
formations, the Chico beds are penetrated by the sandstone dikes already
described.

Their vertical position indicates that they were formed after the tilting of
the Chico strata, and the fact that they are overlapped by the Salt creek
and Tuscan formations demonstrates their existence before these formations
were developed.

After the tilting of the Chico beds, their upturned edges were worn off to
a general level, a base level of erosion ; and in this process the tops of the
dikes were removed also, showing that they were formed between the times
of the tilting of the Chico group and the development of the base level of
erosion across the Cretaceous belt. The Chico beds are the top of the Creta-
ceous, and the dikes which penetrate them could not have been formed be-
fore the close of the Cretaceous. The formations of the Sacramento valley
which are younger than the dikes are Pleistocene, and in part probably
Neocene, rendering it altogether probable that the dikes were formed some-
time during the Eocene or Neocene.

The Dikes occupy Joint Fissures. — Joints are uncommon and poorly de-
veloped in the Cretaceous shales. They were seen chiefly in the vicinity of
sandstone dikes. The latter occupy fissures between joint planes, and it is
evident that the position of the dikes was determined by the joints. It may

132 .1. s. DILLEB — SANDSTONE DIKES

w.l] In- thai the joint- were formed at about the same time as the dikes s
both beiog results of the -aim' general cause; but it is clear that the joints
were formed before the dikes, and that the dikes may be regarded simply as
large join! fissures tilled with Band. There is a complete gradation in the
size of the dikes, from a mere film in a joint, as shown in plate I, figure 3,
up t" s feel in thickness.

\fethod of filling the Fissures. — Fissures in rocks may be filled with mat-
ter brought into them in the gaseous, liquid, or -olid state. When tilled by
the crystallization of minerals from a gaseous or liquid condition, either
that of solution or fusion, the rock produced in the fissure must he more or
less crystalline and easily distinguished from one formed by filling a fissure
with solid particles or fragments of minerals. In the first case the mineral
or mineral- crystallize in place, and if there is no interference in the process
crystals will develop more or less perfectly, a- in the rocks of many igneous
dikes. Bach particle is bounded either by crystal planes or less regular out-
line- of growth due to interference in crystallization which impart a charac-
teristic, non-fragmental structure to the rock in which it occurs.

On the other hand, if a fissure were tilled with particles of solid matter, as
for instance sand, and the whole were cemented so as to form a hard dike
rock, it would have a decidedly fragmental character. A microscopic exam-
ination would certainly show that the mineral particles or grains in the rock
ar>- nut bounded by crystal faces or lines of growth, hut instead by lines of
fracture and abrasion. In the first case the crystals, whether perfect or not.

are a- large a- they ever were; hut in the second case the -rain- are only

fragments of broken crystals, and the term fragmental defines the charac-
terizing feature of t lie rock.

From these considerations it would appear to be an easy matter to dis-
tinguish a rock formed in a fissure by filling it with material brought thither
in a liquid state, either of solution or fusion, from one produced by filling a
fissure with solid particles subsequently cemented ; and Buch is really the
case. The dike rock already described is plainly fragmental, and there can

he no reasonable doubl whatever that the fissures were tilled with sand.

The question at once arises, Whence came tin- sand ? It could not have

Come from the bounding rocks of the dike upon the Bides and ends upon the

surface, for so far as can !"• seen, they are almost always -hale-. It musl
have entered the fissures either from above or below.

[f we .-uppo.-e they were slowly filled from above by loose -and brought

thither by wind or water and dropped under the influence of gravity alone,

the long and broad but thin grains, like scales of mica and other i v or

less foliated mineral-, would generally lie horizontal, as they lie parallel to

' ProfeHonr R. 1>. Irving ilencribe le " velne " on the shore ol i ike Superior, formed by

ea from above ' il Survej Monograph V. Washington, 1883, pp 138

FISSURES FILLED FROM BELOW. 433

the planes of stratification in micaceous sandstone, and would stratify the
dike transversely. It has been shown, however, that the scales of mica in
the dikes do not lie horizontal but stand on edge vertically, parallel to the
sides of the dikes, and that the banding which is in several dikes very dis-
tinct has the same position. It is evident from these facts that the fissures
were not filled from above by ordinary sedimentary processes, but that the
sand was forced into them.

The arrangement of the scales of mica parallel to the sides of the dike is
the one of least resistance, and is a natural consequence of the motion of the
sand as a body in the fissure. It appears to be analogous to the fluidal
arrangement of crystals in eruptive rocks. So far as the position of the
mica and the banding are concerned, the motion may have been in any direc-
tion within the plane of the dike.

That the sand has actually been forced into the fissures is shown by the
effects produced upon the form of the scales of mica. Attention has already
been called to the fact that many scales are crushed edgewise, as represented
in figure 5. In this case the direction of motion is not evident, whether
upwards or downwards in the dike. For the purpose of discovering evidence
concerning the direction of motion in the sand, three thin sections (one hori-
zontal, another vertical aud transverse, and a third vertical and parallel to
the dike) each were prepared of a number of dikes, and a study of them has
thrown considerable light upon the subject. It is easy to understand that
owing to the friction upon the walls of the fissure the sand in the middle
would move more rapidly than that upon the sides, and in this way a
shearing strain would be set up in the grains by their mutual attrition. If
this strain distorted the grains it is evident that the form of the distortion,
considering also its position in the dike, would indicate the direction of
flowing in the sand. In one of the vertical transverse sections the phe-
nomenon represented in figure 6 was observed, and conclusively demonstrates
that the motion of the sand in filling the fissures and forming the dikes was
from below upwards.

It must not be forgotten, however, that the vertical position of the mica
scales, as in many metamorphic rocks, and the banding also, could probably
be produced by movement in the mass as a result of lateral compression after
the fissures were filled with loose sand. But there is no need of appealing to
lateral compression, for the movements at the time the fissures were filled
will explain all the appearances.

A number of dikes fail to reach the surface, and others are offset in such
a manner that it would seem impossible to fill the fissures from above. These
facts strongly support those already adduced, and render it certain that the
sand was forced up from below to fill the fissures.

|:;1 j. s. i»ii.i.i:i: — ujdstone dikes

It is well known thai all rocks a short distance beneath the Burface, within
the accessible portion <>t' the earth's crust, contain water, and thai the amount
that each contains is in a general way proportional to its porosity. It is
evident, therefore, that the loose Band which filled the fissures from below,
being very porous and hounded chiefly by shahs which have a much Lower
degree of porosity, must have I. ecu saturated with water.

It appears that if by any means a fissure wen- suddenly formed from the

surface down to the sand saturated with water the latter would rise in the

fissure and. it* the hydrostatic pressure wen- sufficiently great, the water
would rush forth, carrying the sand with it to till the fissure ami. like an
artesian well, overflow upon the surfai

With a view to determining the possible influence of the fractured strata
in filling the fissures, -Mr. d. Stanley-Brown made for me the Beries of specific
gravity determinations noted in the following table:

Specific Gravity of Dike and J>>>l Rocks.

Shales penetrated by the dikes —

Dry creek, at A. Allen's .... 2.7346 I „ _.,

North fork of Cottonwood, 1 mile above Oaa Poinl 2.7874 | '

Sandstones or beds —

Dry creek. :; miles west of A. Allen's. ._. 2 '.Tor, *\

i on Middle fork, I mile above Miller's 2.68 67-50

in Byron gulch, l mile above Ono. 2.6620

- \ N DSTON BS ok Di k Ks —

Fight gulch 2.68 I

Dry creek, 1', miles above mouth of Salt creek - -

" " •■ ■■ by the road 2.6746

Three-quarters of a mile up Middle fork from filler's .. 2.7006 |

North fork of ( Jottonwood, ■; mile below mouth of Eagle creek *_'.i','.i \Q

'I'he specimens used in the determinations were cut and ground in the form
of cubes with round edges, and at the beginning ami end of' the observation
were dried to a constant weight. The weighings were made directly in water
by means of a tine wire Bupporl and the result reduced, according to Kohl-
rausch's formula, to \ < '.

'I'he sandstone of the dike- appears in the average to he slightly heavier

than that of the beds a fact w inch may he dim to the greater a hum la nee of
biotite in the dike rock-. At the time the fissures were filled, however, the

loose -and must have had a lower Bpecific gravity than now. lor the spaces
between tin grains which were tilled by water or air are now occupied by
carbonate of line-. 'I'he -hah- are appreciably heavier than the sandstones,

and, -inee they ( StitUte tie g] ". :H ma-- of the c.iiutry lock of the < 1 i k • B,

by tlcir weight alone they may have aided in forcing the watery -ami into

THE DIKES MAY BE ASCRIBED TO EARTHQUAKES. t35

the fissures and perhaps out upon the surface; but the greater influence in
producing these results is to be accorded apparently to hydrostatic pressure.

Phenomena commonly associated with Earthquakes. — The phenomena just
mentioned are such as are frequently associated with earthquakes. We are
all familiar with the fissures and craterlets of the late Charleston and
Sonora earthquakes, where the sand and water issued so copiously, in some
cases for several days' after the earthquake. But that we may not seem too
hasty in referring the sandstone dikes to earthquakes, let us examine the
records of such seismic movements and briefly note some of their effects.

During the great Calabrian earthquake of 1783 many fissures were formed
in the ground, and from some of them great quantities of sand and water
issued. After the flow ceased the openings were left full of saud. In our own
country the fissures formed by the earthquake of Xew Madrid, Missouri, in
1811-1813, were still plainly visible in 1846 when Sir Charles Lyell visited
the scene. He says that they were often parallel, and yet there was con-
siderable diversity of direction, varying from 1ST. 10° to 45° W. Many
were yet traceable for half a mile and upwards. It is said that during
the earthquake, powerful jets of water filled with sand and coaly matter
issued from these fissures; and distinct traces of them could be seen after the
lapse of thirty-four years. Similar phenomena accompanied the earthquake
of 1819, at the mouth of the Indus. In all the cases already cited the
fissures were in unconsolidated material only.

During the earthquake of Valparaiso in 1822, however, parallel fissures
were formed in the solid granite of the coast, and could be traced inland for
1 $ miles. Cones of sand 4 feet in height were formed in several districts
by the water, and sand forced up from below through the fissures to the sur-
face. More profound fractures were associated with the great earthquakes
of New Zealand in 1848 and 1855. After the first, a fissure averaging 18
inches in width could be traced sixty miles. At the time of the second, a
fault was formed with a displacement of nine feet, which could be traced for
a distance of ninety miles.

At the time of the Sonora earthquake, May 3, 1887, there were, accord-
ing to Mr. Goodfellow,* extensive irruptions of water and sand from the
fissures formed in connection with the earthquake. These fissures could be
traced more or less continuously for a distance of fifty miles. They mark
the line of a fault, the average displacement of which for the whole distance
was eight feet. It is inconceivable that such profound fractures should
affect the thin covering of soil only ; they must extend as well into the solid
rock beneath.

The fissures and craterlets formed in connection with the Charleston earth-

* Science, Aug. 12, 1887, vol. X, p. 81.
LVII— Bum,. Geol. Soc. Am., Vol. 1, 1H89.

136 .1. S. Mll.r.i: — SANDSTONE DIKES

quake are well known. It is interesting to note thai the sand brought up
to the Burface at that time was, in Bome cases at 1 * -t i — t and perhaps in many,
decidedly micaceous, even more bo than thai in the sandstone dikes.

Of the mineral particles usually found in Band the scales of mica are most
easily transported by water. This fad is sometimes made use of in petro-
graphic Laboratories to separate mica from other minerals in rock powders
by causing water to flow up through the rock powder, regulating the current
so that it will carry up the mica and allow it to escape above through an
outlet, while the other portion of the powder remains behind. The tendency
of this sort of action in Ailing earthquake fissures "would be to render the
Bands brought up to the surface more micaceous than those which remained
behind.

The formation of a system of parallel fissures by earthquakes and filling

them with Band forced up from below is a common phenomenon, and in all

ntial features apparently identical with the formation of the Bandstone

dikes described in this paper. It is reasonable, therefore, to regard these

dike- as a record of ancient earthquake movement.

Th> Region isfavorabli for the Production of sunk Phenomena. — The region
of the dikes is one of earthquakes, also ; and, when we consider its geologic
structure and compare it with that of countries where earthquakes have pro-
duced Buch phenomena, it is found to be well adapted to yield the same
results. Dolomieu's description of the country affected by the great earth-
quake of 1819 about the mouth of the Indus would in a general way answer
very well for the northwestern portion of the Sacramento valley. The
Cretaceous strata, as we have seen in the section figure 8, are bo situated as
to catch and hold great quantities of water flowing eastward from the Coast

Range. Many of the streams sink in crossing the Creta< us belt, and the

Bandstone beds, before they were indurated, must have been < pletely

Bat u rated with water and ready to rush forth under the influence of an
earthquake t" till fissures in the sofl strata with -and.

Source of the Sand in the Dikes. — It has been already remarked that cer-
tain sandstones of the Cretaceous bell are very Like those of the dikes. The
one to which there i- the greatest similarity is near the top of the cascade on
Byron creek, half a mile wesl of Ono. It is a stratum somewhat less than
LOO feet in thickness, with a strike N. LO E. and dip 20 toward the Sac-
ramento. Elsewhere its strike is more to the eastward, nearly parallel with
the western limit of the < Iretaceous terrane, and the average dip is about 15°.
The Bandstone bed outcrops about seven miles westward of the principal

•up of dikes, and dips toward them at an angle ol 15 . [fits dips remain
constant as to direction and angle, as there i- reason to believe, and there is
no faulting, the bed must be in the neighbor! I of 10,000 feel below the

JOINTS DEVELOPED BY SHRINKAGE. 437

surface where the dikes are exposed. The westernmost dike crops out
ou the North fork, just below the mouth of Eagle creek. It must reach the
same stratum at a much less depth, probably within 2,200 feet of the surface.

These figures do not appear to be unwarrantably large, and yet when we
compare them with what is actually known of the depths of earthquake
fissures they seem very deep. Their horizontal extent, however, is not in-
compatible with great depth, for one of them is certainly not less than six
miles in leugth and from 5 to 8 feet wide.

Origin of the Joints in the Dikes. — The peculiar jointing in the dike re-
quires explanation. It may be accounted for in the following manner : The
parallel jointing is developed in these dikes only where the minerals have a
most decided flow arrangement, and the jointing is parallel to this align-
ment. It is a feature which may be well seen in hand specimens. The
direction of the jointing is determined by a sort of slaty cleavage ; but the
fissures are actually developed along these lines of minimum cohesion, prob-
ably by shrinkage.

The transverse joints are of a different nature. Generally, but not always,
the principal system of transverse joints in the dikes is parallel to the strati-
fication of the adjoining shales and sandstones, so that it is evident that the
planes of stratification have some influence in determining the position of
the principal transverse joints. The different strata touching the dike would
vary greatly in porosity. Some being open would take up water rapidly,
and the water would be drawn toward the porous strata on both sides of the
same plane of stratification. The shrinkage in the dike from the loss of
water would produce a strain at right angles to the stratification, and when
the strain becomes greater than the cohesion of the dike it cracks transversely,
parallel to the strata. Occasionally, as in the large dike on Crow creek
(plate 7, figure 1), this system embraces nearly all the transverse fractures
of the dike. Others associated with them may be at right angles to and a
natural consequence of the first, but there may still be other sets whose origin
as shrinkage cracks is not so evident.

The only other change which has taken place in the dikes since their
formation is the deposition of carbonate of lime, which has cemented the
sand firmly together, so that the sandstone of the dike usually has greater
solidity than that of the beds. This larger amount of carbonate of lime in
the dikes is clearly shown by the chemical analyses.

Distribution of the Dikes, considered as Earthquake Phenomena. — The gen-
eral distribution and parallelism of the dikes may be seen in figure 2. Only
the dikes 18 inches or more in width have been represented. The various
exposures which appear to be of the same dikes have been connected. Only
the width of the dikes has been exaggerated. The dotted line to the right

l-*!v .1. S. Mt.l.Ki; INDSTOXE DIKES

lit' the dikes represents the western limit of the newer formations of the Sac-
ramento valley, beneath which some of the dikes disappear. The largest
• like (in the North fork stands alone. The three large ones on Crow creek

■

have been connected with their Bmaller representatives on the North fork a
mile above Gas Point. The Great dike extends from Roaring river to Dry
creek, a distance of 93 miles. Near the western border of the Greal dike

on .Middle fork, at the dam, is another dike 5 feet in thickness, but it is com-
paratively short. Three dikes on Dry creek, Fight gulch, and Salt creek
have been connected as the exposures appear t<> warrant. These dikes are
thickeron Fight gulch than on Dry creek, indicating that they are thinning
out and probably do not extend very far beneath the newer formations.

The general parallelism of the dikes is well shown, although there is a
divergence of 51 degrees iu their strike, ranging from N. 20° to 71° E. The
average strike on the Ninth fork is N. 47° !•'..: on Crow creek, N. 54° E.;
on Squaw creek, N. 53 E. ; on Roaring river, N. 54° E.; in Poverty gulch
N. 43 E. : in Aiken gulch, N. 40° E. : on Middle fork, N. 4"J E. . on Dry
creek, N. 10 E.; in Fight gulch, N. I" E.; on Salt .reek. N. 34° E.; on
the Stage road, N. 38 E. The average strike of all north of Aiken gulch
is N. 4i>° E., and south of it N. 39° E. The more easterly trend of the
northern dikes may he -ecu in the accompanying map. The same bending
to the eastward may be observed in the Great dike. On Roaring river its
average strike is N. 57 E., the lowest being N. 48° E. On Middle fork
its average is N. 11 E., and the highest N. 4-">° E. .

If we regard these dikes as earthquake phenomena their gentle curvature
may indicate their relation to the center of disturbance far to the southeast-
ward in the Sacramento valley. The assures do not appear to belong to the
Sonora or Owen's valley type, in which case the lissures follow the base of a
mountain range and are associated with faulting. In this case the fissures
are some distance from the base of the Coasl Range, and no faulting has
been observed.

Oro8by'8 Theory of the Origin of parallel Joints. — The theory proposed by
M r. W. < >. ( irosby to explain the origin of parallel joints is of interest in
this connection. He regards them as fractures produced by earthquakes,
and the theory has much in it> favor. It is strongly supported by the
phenomena here described. The joints in the gh ales are generally most
noticeable in the neighborhood of the dikes, ami the dikes themselves occupy
joint fissures which must have been formed at about the same time and by
the Bame general movement a- the dikes. Wide fissures, it' hit empty in boA
strata under pressure, would not remain "pen ; their Bides would gradually
come together.

Pi ledlngs Boston Sex Sal History, vol. XXII, p 72

Sandstone Dikes observed in other Localities.

On the voyage of the Beagle in the winter of 1833-34 Darwin observed
three vertical dikes composed of fragmental material some miles up the
harbor above Port Desire, Patagonia. He says :

" The first is straight, with parallel sides, and about four feet wide ; it consists of
whitish, indurated tufaceous matter, precisely like some of the beds intersected by it.
The second dike is more remarkable; it is slightly tortuous, about eighteen inches
thick, and can be traced for a considerable distance along the beach. It is of a pur-
plish-red or brown color, and is formed chiefly of rounded grains of quartz, with
broken crystals of earthy feldspar, scales of black mica, and minute fragments of clay
stone porphyry, all firmly united together in a hard sparing base. The structure of
this dike shows obviously that it is of mechanical and sedimentary origin ; yet it .
thinned out upward and did not cut through the uppermost strata in the clitt's. This
fact at first appears to indicate that the matter could not have been washed in from
above ; but, if we reflect on the suction which would result from a deep-seated fissure
being formed, we may admit that if the fissure were in any part open to the surface
mud and water might well be drawn into it along its whole course. The third dike
consists of a hard, rough white rock, almost composed of broken crystals of glassy
feldspar, with numerous scales of black mica, cemented in a scanty base. There was
little in the appearance of this rock to preclude the idea of its having been a true in-
jected feldspathic dike."*

In July, 1841, Professor J. D. Dana discovered a series of sandstone dikes
at Astoria, near the mouth of the Columbia river, Oregon. f
According to Professor Dana —

" Half a mile above Astoria a sandstone dike five feet wide intersects the bluff from
top to bottom, and may be traced following an east by south course across the flat shores
to the edge of the river. The rock resembles a half decomposed granite, and seemed
at first to be an instance of granite intersecting Tertiary shale. But further examina-
tion proved it to be identical with the granitic sandstone of the opposite shores of the
Columbia. Large fragments and chips of the adjoining argillaceous beds are imbedded
in the sandstone of the dike."

Four other sandstone dikes were observed, ranging from 5 to 18 inches
in width, " and they are generally faulted." Professor Dana remarks :

" These pseudo-dikes of sandstone, were probably formed after or during the depo-
sition of the sandstone while the region was yet under water. Fissures were opened
perhaps by the same cause that ejected the basalt of the intersecting dikes, and the
fissures were filled at once by the granitic sands, along with an occasional fragment of
shale from the walls of the fissure. Their number and irregularity evince that these
regions have been often shaken by subterranean forces."

*GeoIogieal Observations on Coral Reefs, Volcanic Islands, and on South America,1851, Part III, p.
150. In the same volume, part II, p. 100, Darwin mentions dikes of tuff traversing strata of the
same material.

tU. S. Exploring Expedition, under command of Ch. Wilkes, vol. X, Geology (by J. D. Dana),
p. 054.

(439)

I Id .1. S. DILLER — SANDSTONE DIKES

.1. I). Whitney, in bis Geology of California, vol. I, p. 40, saya that at

L Tree cafion, about Beven miles southeast of Corral Hollow, California,

■■ ma — of sandstone were found in the shales in tin- same position with
reference to the Biirrounding rocks a- would be occupied hy dykes. Th<
dyke-like ma- - - m to have originated in the filling of figures by Band
which has since become indurated." Professor W. II. Brewer, who appears
t<> have made the observations upon which Professor Whitney's Btatement is
based, discovered these dikes in middle California nearly thirty years ago;
and it is probable that others will he found in that country of earthquak

Several years ago .Mr. C. D. Walcott collected, near Lake Champlain, a
Bpecimen from what he at the time regarded as a dike cutting limestone.
We were much surprised at the time upon examining a thin section of the

rock to find it sandsl s. In general it resembles the sand-tone dike rock

of California, hut none of the few scales of mica in the section were found
to lie crushed.

Several weeks ago Mr. \V J McGee discovered a number of Bmall saml-
Btone dikes intersecting the Eocene Buhrstone at Corinne, in eastern-central
Mississippi. Mr. McGee kindly permits me to announce this interesting
find, and has furnished material for examination not only from the dikes
hut also from their country rock. < >ne dike is s to 1 L' inch.- in thickm 38,
and another i> 1 inches. Specimens were collected from both dikes. They
an- distinct sandstones to the naked eye, light-colored, almost white, except-
ing where stained yellow by oxide of iron. In the thicker dike the sand
i- firmly lithified, while in the thinner it is rather friable. Both Bides of the
thicker dike are ■' distinctly slickensided vertically," though there is no per
ceptible displacement of the Btrata in the country rock.

The most conspicuous mineral in' the hand specimens of these dike-, as in
those of < lalifornia, is mica. In ( lalifornia it is biotite, hut in Mississippi it
i- muscovite. Another feature which may he Been in the hand specimens i-
that the scales of mica are all approximately parallel, not only among them-
selves, hut also with the side of the hand specimen which Mr. McGee informs
me was the aide of the dike.

Thin sections were prepared of the dike rock in two directions perpen-
dicular to each other and both at right angles to the sides of the dike. The
rock, is composed chiefly of grains of quartz sand, which in many cases ha
been partially rounded. It is of the kind of quartz that is common in granitic
rock- and occasionally contains minute scales of biotite and -mall dark
needles which are well known in granitic quartz. One -rain was observed
apparently with several glass inclusions, such a- are known in the quartz
of eruptive rocks only. ' Occasionally grains of tourmaline are found inter-
mingled with the quartz

Muscovite, although rather plentifully present, is far less abundant than

SANDSTONE DIKES OF MISSISSIPPI. I 11

the quartz, and shows slight traces of lateral crushing. In many cases the
folia are parted and the space between them occupied by cement, as in the
California dike rock. The alignment of the particles and their distortion is
not quite as conspicuous as in the dikes already described, but yet it is
sufficient to clearly indicate the character of the movement by means of
which the fissures were filled with sand.

Of the country rock examined, none of the samples closely resemble the
sandstone of the dikes which, like that in California, is quite constant in its
character. One specimen of the four from the Eocene Buhrstone of the
same locality contains scales of muscovite, but the rock generally is of
finer texture than that in the dikes.

Summary. •

The sandstone dikes upon the forks of Cottonwood creek along the north-
western border of the Sacramento valley in California are over forty five in
number, and crop out at about 112 exposures throughout an area fifteen
miles in length from north to south and six miles in average width.

They are all approximately parallel, with an average strike throughout
the whole area of N. 44° E.

They are usually vertical, ranging from a mere film to 8 feet in thickness
and from 200 yards to 9i miles in length.

They intersect the Cretaceous sandstones and shales along joints, without
distortion or displacement of the strata, and occasionally include numerous
fragments of the shale.

They are sometimes banded vertically parallel to their sides, and the scales
of mica and other lamellar fragments usually stand on edge. in the same
plane.

The dikes are traversed by joints in two principal directions, parallel and
transverse. Unlike the columnar jointing iu igneous dikes, the groups of
transverse joints in the sandstone dikes cross one another directly ; and the
principal group is usually parallel to the stratification of the adjoining
shales.

The dike rock is an impure quartz sandstone containing considerable
biotite. The structure of the rock is unquestionably fragmental, and shows
no trace of crystallization in place of any material excepting the cement,
which is carbonate of lime.

Much of the biotite is crushed in the direction of foliation, that is verti-
cally in the dike, since the scales stand on edge and the distortion of the
particles is such as to indicate that the sand moved upward in filling the
fissure.

Filling fissures in the earth with sand from below is a common consequence

II- J. S. DILLER — SANDSTONE DIKES

of earthquakes natural phenomena which are by n<> moans ran- in Cali-
fornia.

The geologic structure of the region is Buch as to render it especially
favorable for the production of sandstone dikes by means of earthquakes;
and the evidence appears to be conclusive thai these dikes record seismic
movement during tin- Tertiarv.

DISCUSS Joy.

Professor W. M. Davis. — In confirmation of Mr. Diller- suggestion that
detrital material supplied from above would take a horizontal stratification
as it settled into a fissure, I may make reference to the several vertical fault-
fractures in the city trap-quarry, at Meriden, Connecticut. These fractures

traverse a sheet of lava and are chiefly filled with angular trap-fragments,
but the interstices are occupied with sandstone, not in fragments as if it had
fallen in with the pieces of trap, hut in a close-fitting mass as if it had settled
down in the form of separate particles derived from the sandstone originally
overlying the trap-sheet, thus, in a general way, taking a -tincture con-
formable to the blocks of trap that it surrounds, hut showing also a tendency
to a transverse or horizontal stratification. It seems probable that thi
fissures were tilled gradually by infiltration from above, while those that
Mr. Diller describes were tilled suddenly by violent pressure from below.

Professor 15. K. EMERSON: I wish to describe in a word an abnormal vein
tilling which, though occurring on a small scale as compared with the re-
markable cases ju-t described, may have some reaemblai in origin. The

till in the Connecticut valley often requires blasting; and in a deep cellar
excavated in this way a great horizontal sheet ofsands nearly two feet thick
and above sixty feci long was exposed, covered by twelve to twenty feet of

the m08l compact till and separated by two feet of the same firm till from a
heavier bed of buff sands, which was underlain by the till in great thick-
ness. The upper sheel of -ami had plainly beeri moved into its place a- a
frozen block separated from the lower sand, ami it terminated abruptly on
all -ides in the till.

rting in the lower -ami. a fissure had formed, running up through the
two-foot band of till ami the -ami lied, and penetrating two or three feel
into the upper till, then tapering to a point. This fissure was filled with fine
clay, arranged in layers matching each other ami all parallel to the walls of
the fissure. It seems plain that the whole ma-- must have been renl by

-•■in' -train due to the motion of the ice while it wa- itself frozen, and that
by hydrostatic pressure the fissure wa- tilled with mud or muddy water from
below, and that this occurred with several i n t • -rmi — ion- to effecl the band-

milt of the vein.

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA

VOL. 1, PP. 443-452; PL. 9

TERTIARY AND CRETACEOUS DEPOSITS OF EASTERN

MASSACHUSETTS

N. S. SHALER

WASHINGTON

PUBLISHED BY THE SOCIETY

April, 1890

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA
VOL. 1, PP. 443-452, PL. 9 APRIL 21, 1890

TERTIARY AND CRETACEOUS DEPOSITS OF EASTERN

MASSACHUSETTS.

BY N. S. SHALEE.
{Read before the. Society Deerhihn- 2<\, 1SKH.)

CONTENTS.

Page.
General Statement 443

Age of the Martha's Vineyard Dislocations 445

Glacial Origin of Bowlder Beds containing Fragments of Osseous Conglomerate. 449
Detailed Description of Sections 4-">0

General Statement.

In a memoir on the geology of Martha's Vineyard contained in the 7th
Annual Report of the Director of the U. S. Geological Survey, I gave a
preliminary account of the several deposits, mostly of doubtful age, exhib-
ited on the western part of that island. The conclusions there presented
were in the main those which had beeu derived from a study of the district
in the years between 1860 and 1872. Since this memoir went to press, I
have been able considerably to extend my studies in this field. A portion
of the results of this latter work are embodied in a recent paper entitled,
''On the Occurrence of Fossils of Cretaceous Age on the Island of Martha's
Vineyard, Mass.'* In that paper I have endeavored to prove the existence
of middle or lower Cretaceous deposits in the central portion of that island.
About 15 species of fossils are there described as occurring in this deposit,
two of which, au Exogijra and a Camptonectes, appear to afford indubitable
evidence as to the Cretaceous age of the beds.

In all my previous studies in this field it has been difficult to prepare well
determined sections of the principal outcrops for the reason that these occur
on the sea shore and had been extensively covered by rubbly material
which had gradually accumulated. In the autumn of 1888, a rain storm of
great violence, which led to the deposition of about five inches of water in
the course of two hours, scoured off these escarpments in such a manner as

^Bulletin Mus. Comp. Zool., vol. XVI., No. 5, 1889.
LVtir— Bull. Gf.ol. Snc. Am., Vol. 1, 1889. (443)

Ill X. B. SHALEB — DEPOSITS OF EASTERN SfASSACHUSETTS.

to reveal the position of the beds in the sections at < ray I Lead and elsewhere
in a far more satisfactory manner than they have been exhibited during the
pasl -i" years. Making avail of this favorable condition, 1 have been able,
through tin- assistance of my colleagues in the Burvey, to Becure a much
more accurate section of the Gay Head deposits than has previously been
obtained. The section given in the above mentioned reporl on the geology
of Martha".- Vineyard exhibits the beds Bhown at Gay Sead in the form of
an ordinary continuous monoclinal. This was the only interpretation which
was possible at the time this report was prepared. The section here pre-
sented show.- thai the former interpretation of tin- attitude of these beds
was much in error. They are not in fact generally in monoclinal attitude,
lnit are to a great extent singularly compressed, Bomewhat collapsed fold-
ings of the Bt rata.

The taint traces of the-.' dislocations which were visible before the rubble
was cleared from the Gay Head escarpment by the great rain storm above
referred t«» were thought by me a- well a- other observers to be due to
irregular Bliding on the face of the escarpment as tin- detached masses from
the front made their way downward to thesea. The clearer view which has
recently hern obtained has shown tin- opinion untenable, for the foldings
are now traced hack to the portion of the cliff which i- 30 little disturbed
by slipping that the beds are Been in approximately their original attitudes.
It is now perfectly apparent that while some of the lesser folds may he due
to tie- irregular rate of the journey of the masses downward, the main dis-
locations arc clearly of an orogenic nature

Long-continued work on the general surface of the bed rocks, the strata

below the drift, in other part- of the island ha- also revealed the fact that
these deposits as a whole are not of monoclinal type, hut are apparently per-
vaded by similar great foldings. In the Gay Sead district the prevailing
Btrikes of the beds are Bhown on careful review to be substantially th<

Stated in the preliminary report -that is, the axes of the lipid- are in a pre-
vailing northwest and southeast direction. There i-, however, a considerable
variety iii the attitude of the foldings, the range of strike being from N.20
E. toN. L2Q E. A- will he seen by the diagram in plate 9, the orogenic
forces have affected the whole of the section. No portion of the beds appar-
ently retain their original attitude.

In the Chilmark and Tisbury districts, which lie east ami northeast of

Head, beyond the deep depression occupied by Menemsha and Squib-
nocket ponds, a sudden change in the Btrike of the beds i- observed. For a
distance in a northeasterly direction of about !<• miles the beds have an al-
most invariable Btrike of northeast and southwest. Owing to the absence
of good sections, the foldings of the -t rata are not bo traceable as in the < la)
1 1 • .- 1 • 1 section. There appear to be at least two well-defined folds answering

DISLOCATIONS OF THE STRATA. 445

to the main valleys of the Chilmark and Tisbury district; yet others may
be concealed beneath the covering of drift materials. In this connection it
is important to remark that the folds of the Gay Head series are not dis-
tinctly expressed in the topography, and but for the great section at Gay
Head there would be little opportunity to determine their existence. The
amount of dislocation in the Chilmark and Tisbury districts probably is
nearly if not quite as great as that at Gay Head. The average dip observed
at about a dozen points exceeds 45°, and at some points approaches the verti-
cal. The only place where a considerable section is revealed in a clear
manner, viz., at the east end of the Nashaquitsa cliffs, the amount of disturb-
ance is as great as in the most dislocated portion of the Gay Head section.
The total area of the dislocated rocks exhibited on Martha's Vineyard
exceeds 30 square miles. The most considerable width transverse to the
strike is three and one half miles. The degree of disturbance is about, in
a general way, equal in all parts of the section. The only field where the
rocks appear to be slightly dislocated lies immediately to the north of the
Chilmark pond and includes a surface not exceeding one-half a square mile
in area. In this portion of the field the beds, so far as determined by im-
perfect sections, maintain a nearly horizontal attitude. Taken alone, this
relatively undisturbed district might suggest a dying out of the orogenic
action in this part of the field, but considered in connection with the fact
that the section of Nashaquitsa cliffs indicates as intense disturbances as is
found anywhere else in the field, it seems more likely that this unaffected
area is a local accident.

Age of the Martha's Vineyard Dislocations.

The section at Gay Head is apparently divisible into two tolerably distinct
elements, viz: a lower division, the upper limits of which are not determined,
which is likely to prove of Cretaceous age ; and an upper part of the sec-
tion, which from the fact that it contains bones of cetaceans, is likely to
prove of Tertiary age — the two together forming the greater part of the
longitudinal section of Gay Head. Above these two more ancient portions
of the escarpment lie an extended series of unfossiliferous sands, which ap-
parently belong to a somewhat later age than the other portion of the section.
To this age we may also presumably assign the extensive series of beds
exhibited in the Weyquosque series. These later-formed beds are, at least
in the Weyquosque cliffs, deposited unconformably upon the earlier series.
A portion of these later unfossiliferous sands are involved in the contortions
at Gay Head, and a portion of them lie unconformably upon the edges of
the beds which were involved in the dislocation. It seems likely, therefore,
that this later series will in the end be found divisible into two parts — a

146 N. S. SHALER — DEPOSITS OF EASTERN MASSACHUSETTS.

portion which was laid down before, and a portion formed after, the greater
part of the disturbance had been effected.

'flic geological age of the several members of the Vineyard series must
>till lie regarded as somewhat doubtful. The fossils found in Tisbury, near
Indian hill, and described in a bulletin of the Museum of Comparative
Zoology,* show the presence of distinct Cretaceous beds, probably belonging
to the middle or lower member of that series, lying apparently at the base
of the deposits found in place tin this island. The Lower portion of the sec-
tion at Gay Head is likely also to prove of Cretaceous age. The middle
portion of the Gay Head series is presumably of Tertiary age. Although a
good many fossils have been obtained from it, there are none of them of
sufficient determinative value to establish anything more than the general
relations of the deposit. The presence of the cetacean bones and the type
of form of the large shark teeth, as well as the general character of the
molluscan remains, pretty clearly establish the fact that the beds are above
the base of the Eocene and below the summit of the Miocene. On the whole,
the aspect of the fossils is most reconcilable with the supposition that the
beds are mainly, if not altogether, of Miocene age. The uppermost sands
contain no fossils, and their age is therefore undeterminable. Their general
aspect is that of rather recent accumulations, and if we consider the middle
portion of the section as of Miocene age they may perhaps be referred to
the Pliocene section. At any rate, J do not think it probable that they be-
long to the level of the Upper Miocene.

( )n the basis of this determination as to the age of the Vineyard rocks,
we may seek to determine the time when the dislocations exhibited by
this Beries occurred. It is, in the first place, clear that these disturbances,

which folded and faulted the beds, Continued down to the time when the
newest division of the section exhibited at Gay Head was deposited. If
these deposits be of Pliocene age we are compelled to suppose that the
orogenic movements were maintained down to that time. The question
whether the whole of the dislocation took place at this late age is not -"
readily determinable. It i- evident that after the time when the osseous

conglomerate was deposited, w Inch presumably occupies a portion of the Mio-
cene division, the beds were subjected to considerable erosion, which broke
up tli.- depu-it ami delivered pebbles of the material.- to later Btrata. It is
possible, however, that this exposure of the osseous conglomerate to erosive
action was due not to orogenic dislocation but to the laying bare of the beds

while in a horizontal position, in the form of an escarpment, which was

attacked by streams or the sea. So far as is yet determinable, we may assume
either that the dislocation of the strata occurred in one period in the later
Tertiaries or thai it may have happened at various times between the depo*

Op. olt

PERIOD OF DISLOCATION NOT CERTAINLY FIXED. 447

sition of the Cretaceous and the formation of the last beds exhibited in the
section. There are unconformities observed by my assistant, Mr. Wood-
worth, apparently indicating a period of tilting coming immediately before
the deposition of the upper bowlder bed. It will require, however, more
detailed study to determine this point in a satisfactory manner. The rela-
tively slight disturbances of the later sands in the Weyquosque cliffs, if they
be orogenic, as it seems to me likely, would indicate a period of disturbances
coming after the lower members of the Vineyard series had been subjected to
considerable erosion. So, too, the disposition of the later sands in the Gay
Head section also indicate in a tolerably satisfactory way the existence of a
measure of disturbance after a considerable erosion of this series.

It is as yet impossible to determine the area affected by the dislocatory
forces which have operated on Martha's Vineyard. One of the neighboring
localities of apparently the same age as the Vineyard series is that long
ago made known by Dr. Hitchcock, in his Geology of Massachusetts, as oc-
curring in Marshfield, Mass. With the help of my assistant, Mr. C. P. Siu-
nott, I have recently made a considerable study of this deposit. Several
excavations have shown that the area it occupies covers rather more than a
square mile in surface. The whole of the material appears to consist of
layers of greensand, in appearance substantially like those which occur at
Gay Head. It seems, however, from the fossils obtained that the identity
in physical character of the material does not afford legitimate presumption
as to their likeness in age. The few molluscan remains obtained appear to
be of an earlier time than those occurring in the greensands of Gay Head.
They are on the whole reconcilable with the supposition that the Marshfield
series is of Cretaceous age, probably belonging somewhere near the middle
of the series. It is a noticeable fact that these Marshfield beds appear
to retain their original, nearly horizontal, attitudes ; although the bedding is
not very distinct it is sufficiently clear that it is prevailingly horizontal, and
thus shows that orogenic disturbances have not operated in this field since
the layers were accumulated.

My assistant, Mr. Aug. F. Foerste, has observed on Block island beds
which he considers as probably identical in age with those which are pre-
sumed to be Tertiary in the Gay Head series. These deposits of Block island,
according to Mr. Foerste's observations, lie at such angles as to make their
dislocation by mountain-building forces almost certain. I have not myself
had an opportunity of examining these Block island deposits ; but, accepting
the above-indicated observations of Mr. Foerste. it seems clear that we have
a prolongation of the mountain-building disturbances which have affected
this shore to the westward as far as that island.

It will be interesting to determine whether these mountain-building dis-
turbances of late Tertiary age had any part in producing the very extensive

I 1^ V S. SHALER— -DEPOSITS "l EASTERN MASSACHUSETTS.

foldings of the Carboniferous rocka in the neighboring Narragansett basin.
The only evidence on this point is thai above cited from tin- locality at
Marshfield. This locality is situated at the northeastern extremity of the

at Narragansett synclinorium. The presumably Cretaceous beds at this
point are deposited in a great pocket formed by a long-continued land erosion
in the granitic rocks which occupy the anticlinal node at the northeastern
end of the Narragansett basin. The fact that this anticlinal district has
suffered no considerable dislocation is in a certain though insufficient way
evidence that the neighboring synclinorium was nol disturbed during the
period of the Martha's Vineyard dislocations.

It seems to me clear that a very considerable geological time has elapsed
since the disturbances of the Vineyard Beries were brought about. This is
-how n by two classes of evidence: In the first place, on the north Bhore of
the island we have, as is indicated in the section at Cape Higgon, an ex-
tended Beries of deposits to a greal extent composed of unatratified materials
worn from the older rocks which lie iii nearly horizontal attitude- against

the upturned strata of earlier age. The tim scupied for the erosion and

deposition of these sediments musl have been considerable. Next, we note
the tact that the Burface of the island has a strongly accented topography
incised upon the beds of Cretaceous and Ternary age, which was in good
part, at least, developed after the deposition of the last -mentioned horizontal
accumulations. The considerable width of the valleys in relation to the
remaining upland- clearly indicates that the base-leveling process went on
for a long time. Yet further evidence of the same nature is afforded by the
insulated character of the Martha's Vineyard elevation. It is clear that a
deep valley was formed between this elevation and the Bhore line of the
continent to the northward. It is not likely thai any considerable part of
this excavation was accomplished during the last ice period, for the reason
that the Martha'.- Vineyard area was very little eroded during the glacial

time. These points have in the main been noted in my report <>n the island

of Martha'.- Vineyard, bul t heir importance is now more evident than before.
The evidence in this way obtained appears to indicate thai while the last
disturbances of an orogenic nature which have affected the Vineyard series
are of relatively recenl geological time, the period which elapsed unce their
conclusion and before the coming of the last ice-sheet was really great.
Although the evidence can noi be fairly presented in a numerical way, it seems
to in- . considering the' amount of erosion as well a- the remaining evidence
of depositional work, that the time intervening between the close of the
Vineyard movements and the beginning of the later glacial period must
have been at least twenty time- a- long a- thai which ha- elapsed since the
departure of t he ice from this Held.

In the before-mentioned report on the geology of Martha's Vineyard I have

TREND OP AXES OF DISTURBANCE. 449

adverted to the fact that the dislocations at Gay Head have led to the de-
velopment of axes of elevation having at that pointa prevailing northwest and
southeast direction. It should be made clear that later studies on the island
have shown that this axial direction is not maintained throughout the area
of the island. The greater part of the beds in the towns of Chilmark and
Tisbury exhibit a northeast and southwest trend. It thus appears likely
that the dislocations of this time present a considerable variety in the axial
direction of the folds, a portion of them departing widely from the prevail-
ing strikes of the eastern portion of North America, while the larger part
conform to that general axis.

Glacial Origin of Bowlder Beds Containing Fragments of the

Osseous Conglomerate.

Among the more important results obtained in the later studies on the
Gay Head section is one which in a measure serves to affirm the glacial
origin of this deposit. In my memoir on the Geology of Martha's Vineyard
in the 7th Annual Report of the Director of the U. S. Geological Survey, I
have called attention to the fact that a portion of the beds exhibited in the
Gay Head series are presumably of glacial origin, formed during an ice
epoch occurring in Tertiary time. This evidence was clearest in the case
of the conglomeratic beds which abound in certain portions of this section.
The facts in hand at the time when the above-mentioned report was pub-
lished were not sufficient to affirm this hypothesis. During the last summer
my assistant, Mr. J. B. Woodworth, was so fortunate as to discover in the
conglomerate exhibited just south of the depression known as the Devil's den
a fragment of ilmeuitic rock which certainly was derived from Iron hill, near
Cumberland, Rhode Island. The character of this material is such as to
make its origin quite unmistakable. The dense, fine-grained magnetic oxide
contains a large number of feldspathic crystals, giving the rock a very char-
acteristic expression.

During the last glacial epoch a bowlder trail was formed from Iron hill
down the valley in which lies Narragansett bay and thence eastward to the
peninsula of Gay Head, whereon the fragments of the material are thinly
distributed. This fragment imbedded in the Gay Head section was discov-
ered at a point indicated in the section. There seems to be but little doubt
that it was actually imbedded iti the mass of the conglomeratic material.
Although found on the basset edge of the deposit there was no distinct coat-
ing of glacial drift above it, and it has the superficial color proper to the
deposit in which it is supposed to have belonged. Moreover, the surface of
the fragment is deeply pitted by decay in a manner exhibited by none of
the many thousand other fragments which were found in the trail formed

loO N. S. SHALER — DEPOSITS OF EASTERN MASSACHUSETTS.

during the lasl ice epoch. It therefore does not seem tome possible that
the pebble could have been driven down iuto the superficial portion of the
old conglomerate by the recenl glacial action. It should furthermore be
noted that the ancienl conglomerate contains a great number of hypogene
bowlders which have the same general lithological character as those which
wen- transported to this region from the Narragansetl basin during the lasl
glacial period. On the supposition thai tins old conglomerate is of either
Mine. -in' or Pliocene age it thus becomes mure probable than before thai it
i- of glacial origin. The fragment in question is about * by 5 by 3 inches-
and weighs aboul ten pounds. 'Before attacked by decay it was evidently
of an angular form, such as usually characterizes the pebbles of this very
hard material even where they have been transported for the distance of 50
miles or more. It seems impossible thai it could have owed its carriage to

water action, and it therefore affords importanl additional evidence to prove
the glacial origin of the deposil in which it occurs.

Assuming that the bowlder beds containing the erratics from the Narra-
gansett basin arc of glacial origin, the question manifestly arises whether
this deposit can be regarded as equivalent in age to the deposits formed
during the firsl advance of the ice over the central portion of the continent.
bul which have hitherto not been clearly observed in New England. It is
.-till too soon to decide this question. It may he noted, however, that it'
we regard the above named deposit- at Gay Head a- belonging to the lasl
glacial period, we are called on to assume the occurrence of a very great

interval between the first and se< 1 advances of the ice. tor the extensive

subaerial topography of Martha's Vineyard was evidently developed after
these lied- had been deposited and uplifted into their present attitudes.

I >i i wi.kd Description of 8e< tions.

The accompanying illustration ( plat.- '.» i contains three sections: the upper
fig. 1 a diagrammatic and partly ideal section from Vineyard sound south-
eastward to the valley ..f Ti-burv river neai- the point known a- the upper
I ' idier pond : the middle (fig. 2), divided into three parts, shows the section
of the beds in the Gay Head escarpment so far as they have been interpreted ;
while the small diagram at the bottom of the plate (fig. 3) affords a theo-
retical interpretation of a certain puzzling section of the escarpment.

The first section I fig. 1 ) is intended to indicate tin- evidence which 3erV6fl

to -how that the drainage of tM- country had been completely developed
before the advance of tin- lasl glacial sheet. It will be observed that the
glacial detritus forms hut a thin coating "ii the lower ridges, and ha- .i
thickness of only about 20 feet on the higher. At the point selected the
glacial waste forms a much thinner -he. t than i- usual in this part of the

DETAILS OF THE GAY HEAD SECTION. 451

island. A little to the southwest of the highest point in the section the
moraiual material probably has a thickness exceeding 100 feet. This sec-
tion is intended also to show that while the Cretaceous and Tertiary beds
(the age of which cannot at this point be determined) lie at a high angle,
the average declivity exceeding 45°, there lies against them to the north-
west a thick section of beds supposed to be of preglacial or interglacial
age which have not been disturbed. These horizontal beds are probably
of the same age as those which lie unconformably upon the upturned and
eroded strata at Gay Head, where they are shown both in the northern and
southern extremities of the section. As is indicated in the section, they are
well developed from 800 to 1,200 feet west of the steamboat landing. Simi-
lar deposits exist along the northwest face of the island from Chappaquon-
sett pond westward. They probably also occur at the base of the cliffs at
Cottage City, and also in the easternmost portion of the Nashaquitsa cliffs
near Chilmark pond. On the northern shore and also near Chilmark pond
these deposits contain occasional waterworn fragments of fossils derived
from the Tertiary strata against which they lie.

The Gay Head section (fig. 2) begins near the steamboat wharf on the
shore to the northeast of the light, and extends in a general westerly trend
for about 1,000 feet ; next in a prevailingly southerly course for about 2,500
feet; then it swings in a southeasterly direction, where it terminates at 6,200
feet from the point of beginning. The delineation exhibits the apparent
dips at the points of outcrop, and therefore must not be regarded as a cross-
section. The object of the delineation is to give as nearly as possible the
aspect of the beds in the present condition of their exhibition. Owing to
the fact that the strata are evidently very discontinuous, it is not possible to
determine their attitudes at any distance from the outcrop. At certain
points, as, for instance, at 4,100 feet from the wharf, the beds are delineated
in as yet unexplained positions, care being taken to exclude from such de-
lineation strata which had come to their position by slipping down the face
of the cliff. At the point indicated as " the Devil's den " there is a deep
recess in the face of the cliff. Here the soft clays and sands, standing at a
high angle, have yielded readily to erosive agents which have carried the
escarpment back more readily than it has elsewhere been worn away by the
sea.

A number of thin lignites, apparently having no considerable extension,
are omitted. All the other distinctly determined strata are drawn. The
blank spaces indicate portions of the escarpment at present so far covered
by detritus that the stratigraphy of the underlying beds has not been deter-
mined. At only one point has it appeared possible, in the present state of
our information, to infer from the existing remnants of the strata the posi-
tion and character of the folds, viz., at the part of the escarpment between

LIX— Bull. Geol. Soc. Am., Vol. 1, 1889.

!"».! V S. SHALES — DEPOSITB OF EASTERN MASSACHUSETTS.

1,900 and 2,400 feet from the datum point. < >thergrea1 folds doubtless exisl
in the section, as is Bhowo by the facl that at 1 ,.'>()< i feet the greensand and
associated beds exhibit the series in reversed order. This fold probably re-
turned through the eroded portion of the beds to Bome point in the covered
portion of the escarpment from o(H) to loon t * - * - 1 to the east. There is an-
other great fold obscurely indicated near the Devil's den, the extension of
which is as yet undetermined. Although a number of faults are indicated
in the section, there are doubtless others which have escaped observation,
1 n no other way than by a combination of faults with folds can the frequenl
inversions exhibited in this diagram be explained.

It will lie observed that over a good part of this district the glacial drift
is not traceable. I ts absence is conspicuous between station 4,100 and the
end of the section. The drift also exists in the area near the wharf, but it
was not delineated because the escarpment was grass-covered and it was dif-
ficult t<> discriminate the glacial from the lower-lying deposits.

Between stations 2,000 and 2,100, at a height of 80 feet above the sea, a
small patch of interglacial or preglacial deposits containing abundant frag-
ments of shells of living species was found. As the portion of the deposit
which remained did not contain more than lo or 15 cubic feet of material, it
was impossible to determine its exact relation to the remainder of the section.
It is possible that the material came into it> position by sliding from a more
elevated position.

It give- me pleasure to Btate that 1 am indebted to several students of
Harvard University for assistance in the preparation of this paper. A large
part of the detailed work was done by Mr. J. R. Woodworth. The whole
of the sections contained in the plate were drawn by him, and the greater
part of the recent field work on this escarpment is due to his labor.

BULL Gf.OL.SOC. am

VN[YAR0 SOUND £

• -.luLMJIAL OR INTERGLACIAL FORMATION

FJG.l. SECTION 1 MILK LONG. FKOM VINEYARD SOUND. (i\ Mi. K...f CHiggoiO TO VM

■

.'i — » (.HO01

,B-/„,jtl> fOOM iKOHHUt. H

(tHXtK-l •■■.WO

RECENT AND LAST GLACIAL

INTERGLACIAL AND PREGLACIAL

__^^ 8. Sands and Clays
trial Drift and Blown Sands » 7. Ferruginous Sands

6. G/oki?/ a/?^ Boulder Beds

KKi<. VISIBLE SECTION 0

(DISTANCf

HOP

FIG. 3.

VOL.1, 1889, PL. 9.

DRAINED BY THE TISBURY RIVER ($ Mi W. of N. Tisbury P 0) MARTHAS mTEYARD.

•/BIN

jaoff Alt

|t/c»)

[«

MIOCENE

b. Green Sand Beds and Boulders of No. 4. . .
A. Osseous or Quartz Pebble Conglom

\Y HEAD CLIFFS IN 1880.

'EN IN FTET)

CRETACEOUS

3. W?/te Micaceous Sands and Clays.

^ 2. Noduled- Clays and Leaf Beds g^^

I. Lignite Beds

S SAND

E SANOS I CUtS
• REENISH SANOS

.FERRUGINOUS SAN0

GREENISH SANOS

WHITE SANOS & CLAYS

vE SECTION PCRPl MOLAR TO
E AT 1500ft TTOM WHARF

BULLETIN. OF THE GEOLOGICAL SOCIETY OF AMERICA

VOL. 1, PP. 453-468; PL. 10

THE STRATIGRAPHY OF THE "QUEBEC GROUP"

R. W. ELLS, LL. D.

WASHINGTON

PUBLISHED BY THE SOCIETY

April, 1890

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA

VOL. 1, PP. 453-468, PLS. 10 APRIL 23, 1890

THE STRATIGRAPHY OF THE " QUEBEC GROUP."

BY R. W. ELLS, LL. D.
(Read by abstract before the Society December 28, 1889.)

CONTENTS.

Page.
Introduction 453

Historical Review 454

Bigsby's View 454

Bayfield's View 454

Logan and Richardson 454

Hunt's Studies 455

The Founding of the " Quebec Group " 455

Richardson's later Work 457

Hunt's later View 457

Selwyn's Classification 457

The Gaspe Studies 458

Recent Investigations 458

Work in the Eastern Townships ._ 458

Work on the St. Lawrence 460

The Succession about Levis and Quebec 464

The Stratigraphical Succession 464

The Paleontological Succession 465

Conclusions 466

Introduction.

The discussion of the various opinions which have been put forth from
time to time during the last half century as to the age and geological posi-
tion of the different members of the peculiar series of rocks known among
geologists generally by the term " Quebec group," would be an undertaking
too great for the limits of an ordinary paper. It is, moreover, to a great
extent rendered unnecessary in this place from the fact that the history has
already been given with considerable completeness in several publications,
among which may be chiefly enumerated papers by Dr. T. Sterry Hunt and
Professor Jules Marcou, as well as by the writer, who, in the volume of the
Geological Survey of Canada, just issued ( l<S87-'88), has gone into the sub-
ject with some detail. This course was deemed advisable, and in fact almost

LX— Bun.. Gkol. Soc. Am., Vol. 1, 1889. (^53)

l-"l K. W. ELLS — STRATIGRAPHY OF THE "QUEBE( GROUP."

necessary, owing i" the variety of statements, many of which are very con-
flicting, which have appeared "ii this subject from a large number of writers ;
much bo that, even in the case of those who have endeavored to follow out
the discussion most closely, much difficulty lias been experienced in arriving
at ajust conclusion as to the real geological position of this group of rocks.
When we consider that the bibliography of the subject embraces not li
than twenty nanus ami extends over a period of sixty-two years, or from
1827, when a j »:i j u- 1- by Dr. Bigsby first appeared, ii can be readily under-

st 1 thai the task of getting so many diverse opinions together tin- the Bake

of comparison is no very easy one.

Histork Ai. Ul.YI EW.

Bigsby's View. — It is probably unnecessary to spend much time in the con-
sideration of the earliest views expressed regarding the age and structure of
tiii- group. About Quebec ami Levis when' tiny were first studied by Dr.
I tigsby, they were regarded a- the probable equivalents of the Carboniferous
of England — a view doubtless to some extent arising Prom the presence of
considerable areas of blackish bituminous Limestone which occur in that
vicinity, ami certain curious deposits of black coaly, or rather pitchy, matter
found in joint- and -cam- in both the sandstones ami shales at various points,
the true nature of which was not at that time fully understood.

Bayfu ill's View- — The next writer on the Bubject I Admiral Bayfield, 1845
assigned them to a much lower position, and regarded them as the equivalents
of the Lower Silurian in their lower strata, passing into the Lower portion
of the Upper Silurian or Oneida at their summit. This view obtained great
favor, and, from L845 marly to I860, the opinion was expressed by all the
Canadian geologists that the great area of rocks extending southeastward

from the St. Lawrence river ami including the untain ran-'- of the

eastern townships, or central and southeastern Quebec, represented Bome
portion of what was then regarded a- Middle Silurian ami largely of the
Hudson River division of the Champlain group of the New York geologists.
Not only did this classification embrace the comparatively unaltered ami
often fossiliferous Bediments of tie- St. Lawrence basin, hut the great -cries
of crystalline schists, gneisses, and associated rock- of the interior a- well ;
these latter being regarded simply a- the tnetamorphic equivalents of the

jsiliferoue portion, from which all traces of organic life had been removed
by the changes to which it was claimed they had been subjected. Thi
altered or crystalline rocks were at the game time regarded as occupying
synclinals in the lower or fossiliferous slat

/ /■/// mi'l Richardson. The Btudy of the rocks aboul Levi.- ami along
the south Bide of the St. Lawrence river in i he peninsula of Gaspe" revealed

THE FOUNDING OF THE " QUEBEC GROUP." 455

the presence, at many points, of great numbers of fossils, principally grap-
tolites. Large collections were made by Logan, Richardson, and others,
which were submitted to Professor James Hall, of Albany, and upon exam-
ination were found to be in many respects unlike those from the recognized
Utica or Lorraine of New York; but they were at the time regarded as
probably representing the Hudson River division of the Champlain group.

Hunt's Studies. — Hitherto the views as to the Hudson River age of many
of these rocks were held to be firmly established by the stratigraphical suc-
cession of the beds; since there appeared to be a regularly ascending series
from the well-defined Trenton on the north side of the St. Lawrence to the
summit of the fossiliferous shales of Levis. Further collections of fossils
were, however, made from the rocks opposite Quebec, and in 1856 Dr. T.
S. Hunt succeeded in finding in the limestone beds of Levis the imperfect
remains of a trilobite which appeared to be new. Stimulated by this dis-
covery, a vigorous search was at once commenced in the calcareous beds of
that place, and many of these were found to be richly fossiliferous — so much
so that in a short time nearly 170 species were obtained, not including the
graptolites. These were handed for determination to Mr. E. Billings, who
found that of this number five were peculiar to the Chazy and twelve to
the Calciferous, while yet others had a true Potsdam aspect, and none were
observed which indicated a Utica or Hudson River horizon.

This somewhat startling discovery at once overturned the conclusions so
long held as to the Hudson River age of the strata at Levis and vicinity,
and led to the reversal of their positions from the top to the base of the
Champlain division.

The Founding of the "Quebec Group." — After a careful examination of the
evidences obtained by Billings, Sir William Logan, in a letter to Barrande,
dated December, 1860, and made public in March, 1861, in the American
Journal of Science, expressed the opinion that these rocks represented a great
development of strata about the horizon of the Chazy and Calciferous,
brought to the surface by an overturned anticlinal fold, with a crack and
a great dislocation running along the summit, by which the rocks in ques-
tion were brought to overlap the Hudson River formation. At the same
time he stated that "from the physical structure alone no person would sus-
pect the break that must exist in the vicinity of Quebec, and without the
evidence of the fossils every one would be authorized to deny it." To these
rocks the name "Quebec group" was now for the first time applied.

With the light thus thrown upon their structure by the determination of
the great series of fossils from the Levis beds, the new " Quebec group "
now entered upon an entirely distinct stage of discussion. It was soon divided
into two portions, styled the Levis and the Sillery, of which the former was
again subdivided into seventeen parts, representing a total thickness of 5,025

456 K. W. ELLS — STRATIGRAPHY 01 THE "QUEBEC GROUP.

feet, and in which was comprised a considerable variety of sediments. Some
of these contained an abundance of fossils, while others were comparatively
barren of organic remains. The lowest portion was supposed to consist of
greenish shales, mostly calcareous and magnesian, l>nt having interstratified
beds of purple color. These graduated upwards into grayish argillaceous
-hales and limestone conglomerates, with which were closely associated
bands of dolomitic Limestone and olive-green slates, the latter containing
glauconite. In the upper part of the section, beds of gray sandstone and
grittv conglomerate occurred together with others largely composed of j»<1>-
bles of limestone in a gritty or sandy paste. The upper members consisted
chiefly of dark gray and green Blates with quartzites, which were interstrati-
fied with a Beries of red and green Bhales, the latter containing fossils, among
which were recognized two Bpecies of LingtUa and an Obolella presumably
pretiosa. Some doubt, however, existed as to the true ascending sequence
of these several divisions, owing to the fact that of the Obolelln found in the

en slates several allied species were also recognized in the Potsdam for-
mation elsewhere, as well as in what had been regarded as the Calciferous
of New York.

Succeeding the red and green shales, which for the time at least were re-
garded as constituting the upper portion of the Levis formations, came a
series of greenish gray sandstones of peculiar aspect, with shales of various
colors — red, green, gray, and black — having an estimated thickness of li.ooo

feet. These composed the Sillery division, and were then held to constitute

the upper portion of the Quebec group.

In 1864 the Levis formation was again divided into two parts, of which
the upper, comprising a thickness of :5,74<> feet, was separated under the head
of the Lauzon. This embraced the hulk of the olive-green and red shales
with their associated sandstone- and quartzites, the sequence in ascending
order now being L<'vis, Lauzou, and Sillery. In the report of the Geologi-
cal Survey of Canada for 1866 the Levis or lower division was said to be
distinguished by it- generally black or dark color, and was stated to contain
nearly all t he fossils found in the group, and from the evidence of these fossils
the geological position of the base of this division was held to be about the
summit of the Calciferous. The middle division, or Lauzon, was marked
by a predominance of green and purple -hade-, the fossils found being only
three -the two species of LingtUa and the Obolella already noted — which oc-
curred near it- BUpposed Summit. It was, however, further distinguished by

the presence of two magnesian hand-, one at the base and the other near the
top, both characterized in what was regarded as it- metamorphic equivalent
by the presence of metallic ore-. The upper, or Sillery, in its unaltered con-
dition consisted of the green Bandstones with their associated shale-, which
in their altered Btate were Bupposed to form the series of highly crystalline

VIEWS OF RICHARDSON, HUNT AND SELWYN. 457

schists and epidotic or chloritic rocks of the mountain ranges of the interior,
and which, at their highest part, were also supposed to shade upward into
more or less perfect gneisses. It was found difficult to draw any sharply
defined line between this division and the underlying Lauzon.

Richardson's later Work. — The views as to the structure of the Quebec
group just stated remained unchanged till 1868, when Mr. James Richard-
son, in the course of his explorations along the south side of the St. L'awreuce,
upon the evidence of certain fossils there found, advanced the theory that a
portion of what had been regarded as Sillery and Lauzon was in reality
of Potsdam age and divisible into three parts — lower, middle, and upper.
The rocks to which his conclusions more particularly applied embraced cer-
tain extensive areas of hard quartzose sandstone, with associated beds of
limestone conglomerate, together with slates of various colors. These he
considered to underlie the Levis formation, which was, however, still regarded
as being older than the Sillery as first established. The reasons for this
change of view were principally the finding of fossils of Primordial age in
some of the conglomerate bands, and the presence of supposed Scolithus
burrows in certain of the quartzose sandstones, many of which in their
character were supposed to resemble those of Potsdam age west of Montreal.

This view was not very strongly supported by Sir William Logan, who,
upon examination of the evidence, failed to find anything which could con-
clusively establish their Potsdam horizon ; and subsequently the subject was
discussed by Dr. Selwyn, who also failed to find any sufficient reason for the
separation of the so-called Potsdam portion from the original Sillery sand-
stone.

Hunt's later View. — In the meantime Dr. Hunt, in 1871, had propounded
new views as to the structure of the group, more particularly relating to the
supposed altered portion of the interior, in which he claimed that these
metamorphic rocks were not the equivalents of the fossiliferous Quebec group,
but belonged to an entirely distinct system, and that they should be regarded
as older than the Cambrian as then constituted or as a portion of the
Huronian, thus completely overturning the views so long maintained as to
their equivalency with the Sillery and Lauzon divisions.

Sehvyn's Classification. — The study of these rocks was taken up at a later
date by Dr. Selwyn, then director of the Geological Survey of Canada, who
in 1877 first officially published the opinion that the original Quebec group
was divisible into three great systems, viz : (1) An upper portion, styled the
Lower Silurian, which comprised the Levis and Sillery (the name Lauzon
having been dropped) unaltered and in places fossiliferous rocks ; (2) A
volcanic group, probably lower Cambrian, which included quartzose sand-
stones, red, green, and grayish siliceous slates, serpentines and diorites with
dolomites ; and (3) a group composed of slaty and schistose, chloritic, mica-

I">s K. \v. ELLS — STRATIGRAPHY <»K THE "QUEBEC GROUP."

ceous and other rucks, with gneisses and crystalline limestone, the whole
somewhat closely related to the precediug but regarded as forming an un-
derlying series of probably Huronian age. These constituted the metamor-
phic ridgea of the Sutton mountain range and its extension northeastward
to and beyond the Chaudiere river. The views thus presented by Dr.
Selwyn wire stated, with some slight modification, in several subsequent
papers.

Tfu Gaspe" Studies. — In lss'_' the survey of the Gaspe* peninsula showed
clearly the pre-, nee of an underlying series of crystalline schists, hornblen-
dic and chloritic, with epidotic and other rocks, which formed a large part
of the Shick-shock mountains and which evidently represented the eastward
prolongation of those just described. These were flanked on the south Bide
for the greater part of their extent by Silurian strata, hut on the north, be-
tween the mountain range and the St. Lawrence, a considerable thickness
of green and dark gray slates, in places Bchistose, occurred ; while the area
between these and the river was occupied by the red ami green slates, with
the sandstones and occasional conglomerates of the original Sillery and
Lauzon divisions. These rocks extend continuously from Le'vis to Cape
Rosier, near the eastern extremity of the Gaspe peninsula, and are exceed-
ingly uniform in character throughout. At very rare intervals an overlying
outcrop (1f fossiliferous Levis shales is found.

Towards the lower part of the St. Lawrence these rock- are underlain by
black shales and Limestone, often highly bituminous, and iu places by a
gray sandstone, the whole containing graptolites and other fossils of Bud-
son River and Trenton-Utica age. Their apparent underlying position is
doubtless due to a line of fault, the continuation of that Been on the north
side of the island of < Orleans and the course of which, in it- extension down
the river, was described by Sir William Logan in the earlier reports of the
survey. From certain peculiarities of structure at that time observed, it was
thought that the true position of the Sillery might really he the reverse of
what had bo long been maintained, and that it should form a Lower Btrati-
graphical series than the Levis, thougb the work necessary i" t he final estab-
lishment of ihi- point was lor the time deferred.

I! I < I vr I.NV E8TIG LTIONS.

Work in iIk Eastern Townships. — In 1885 the detailed examination of the
k- of the Eastern Township- was begun by the writer. Commencing at
Sherbrooke, tin- work extended on the we-i to Richmond and on the east to
the boundaries of Maine and New Hampshire. The results of the two years
survey of this section appeared in the annual volume of the Geological
Survey Reports for 1886, accompanied by a map of the southeastern part of

DIVERSE FORMATIONS OP SOUTHEASTERN QUEBEC. 459

the province of Quebec. In this map many changes in the geology of this
area, as compared with the formations indicated on the general map of
Canada, 1866, are apparent. It was found that much of what was then
regarded as of Upper Silurian age, comprising the great stretch of country
lying to the east of the Sherbrooke and Lennoxville belt of crystalline schists
and forming the extension northward of the rocks described some years
before by Professor Hitchcock as the Calciferous mica schists and Coos
groups, really belonged, in great part, to an older system. This fact was
established not only by its unconformable position beneath fossiliferous
Silurian rocks, but by the finding at several points of Cambro-Silurian fossils,
both in the limestones of the series and in certain interstratified beds of
black graphitic slates. The fossils comprised graptolites of Trenton-Utica
age, as determined by Professor Charles Lapworth, similar in character to
those obtained from the graphitic shales of the south side of the St. Law-
rence— recent examinations having disclosed the presence of these in large
quantities and in an excellent state of preservation — together with criuoids
and other forms, which under the microscope were found to indicate a hori-
zon of the lower Trenton or possibly upper Chazy. The Upper Silurian
areas were limited to basins of small extent or closely infolded beds, and
were in all cases clearly distinguishable by their characteristic fossils.

The underlying rocks were divisible into at least two portions, of which
the lower or crystalline series, composed of schists of various kinds with epi-
dotic, chloritic, and dioritic rocks, occurred as well-defined anticliuals. Of
these, in the section from Richmond to Maine, three principal axes were
recognized. The first axis, or that near Richmond, was traced and found to
be the extension of the Sutton mountain anticlinal, formerly recognized by
Dr. Selwyn ; the second or middle axis passed through Sherbrooke ; and the
third constituted the belt of high land along the border of New Hampshire
and Maine, the character and probable age of which had been indicated by
Professor Hitchcock some years before. In all these the rocks present
great similarity in lithological aspect, and are frequently flanked by slates
and conglomerates with interstratified beds of hard quartzite or quartzose
sandstone, in places having a somewhat schistose structure. In these areas
of crystalline rocks the principal deposits of metallic ores are found, and
they are now regarded as of pre-Cambrian and probably Huronian age.

The series intermediate between that just described and the rocks of the
great Cambro-Silurian eastern and central basins comprises slates, mostly
blackish and often wrinkled, but also of green and purple shades and with
interstratified beds of hard grayish sandstone which sometimes becomes a
bluish-gray quartzite. In places these rocks are unconformable to the un-
derlying schists, and contain masses of conglomerate often of considerable

"^TTT-T.T^ ^T^T.. "

460 R. W. ELLS — STRATIGRAPHY OF THE "QUEBEC GROUP

extent, sonic of the pebbles in which are derived from the debris of the pre-
existing hills in close proximity and just described. Owing, however, to
the great folding which these have all undergone, the two series frequently
appear to be conformable. They have not a,s yet been found to contain
fossils, but this is doubtless in some measure owing to the fact that but little
attention has been devoted to this aspect of the case. They are, however,
in all probability the equivalents of those which flank the Green mountains
to the south and from which Walcott has obtained his lowest Cambrian
fauna. In the area east of the Sherbrooke anticlinal the upper part of the
Cambrian is concealed, but on the west side of the Sutton mountain range,
towards the plain of the St. Lawrence, this upper portion is displayed in
tic red and green slates aud greenish sandstones which we recognize as the
Sillery proper and into which the slaty andquartzose beds of the lower Cam-
brian appear to graduate.

In connection with the lower Cambrian of this area, large masses of ser-
pentinous rocks are found. These are in many cases associated with diorites
and sometimes with granitic masses. Frequently the serpentine appears as
knolls surrounded by slates and sandstones. In some places the slates in
contact are bluish-gray roofing-slates, as at Melbourne; in others they are
reddish or purple, black or gray, as at Coleraine. In Thetford and Brough-
tou the rocks with the serpentine are quartzose sandstones and bluish-gray
and black slates, as is also the case in the Chaudiere river section. Serpen-
tines are. however, occasionally found with schistose rocks which are regarded
as of pre-Cambrian age, so that it would appear that they are not confined
to either one of the great geological systems.

Work on the St. Lawrence. — That portion of the Quebec group more im-
mediately bordering on the St. Lawrence possesses, however, special interest
from the facl of its containing fossils at many detached points. During the
years 1887—88 much detailed work was done in this section with the object
of determining, if possible, the true stratigraphical relations of the several
divisions, and of conclusively solving the question of the relative position of
the Sillery and Levis, deferred from 1-SH2. The results of this work have
just appeared in the report of the Geological Survey of Canada, 1887 '88, a

brief outline of which may serve to make clearer BOme of the puzzling ques-
tion- of stratigraphy and paleontology there presented.

Of the three anticlinals described in the southeastern portion of the prov-
ince, but one, viz., thai of th" Sutton mountain, is visible in this direction.
This extends for many miles with ;> regular uortheasterly course, and, with
Borne breaks, the Beriee of schists and crystalline rocks already described can
be traced into Gaspe\ A- in the sectional Sherbrooke, the schistose series
is overlain on either Bide by the black -late- ami quartzites of the lower

ROCK DIVISIONS ON THE ST. LAWRENCE. 401

Cambrian ; but in the section south of Levis these are in turn succeeded by
the great series of red aud green slates of the Sillery, which, thrown into
complicated folds, occupy a surface breadth of some miles between the river
and the interior ridge. All the formations here developed have a very uni-
form strike, following for the most part the trend of the St. Lawrence. In
the course of our examinations, many sections were made directly across
the measures, the structure in nearly every case proving to be the same and
sustaining the views already expressed in regard to the southeastern area.

What we now consider the lowest portion of the unaltered Quebec group,
as developed in the vicinity of Quebec and Levis and for some miles south
of the latter place, is seen in a sectiou on the north side of the St. Lawrence,
beginning about ten miles above the city of Quebec. From this point, which
marks the line of fault bringing into contact the rocks of the Hudson River
formation, what appears to be a regularly ascending sequence of beds is ob-
served till we reach Pte. a Pizeau, about two miles above Quebec, in the dis-
trict of Sillery. This section we have divided into four parts, and may briefly
summarize as follows :

Division 1. Consists largely of quartzose sandstone interstratified with
black and gray shales, and contains at one point a band of fine conglomerate
made up of small pebbles of limestone and quartz in a highly siliceous paste.
No fossils have yet been found.

Division 2. Comprises green, black, and gray shales or slates, with occa-
sional bands of hard sandstone. Thin beds of purple-tinted slates occur in
the upper portion. Many of the slaty surfaces are covered with worm trails,
styled fucoids in the earlier reports of the Geological Survey. These beds
are also well seen on the hill in the rear of Cape Rouge village.

Division 3. Comprises mostly reddish and green shales without sandstones,
or with the latter in but small quantity.

Division 4. Consists of sandstones largely developed, with partings (often
of considerable thickness) of red, gray, green, and black shale. The sand-
stones are local, the areas thinning out in either direction ; and the green
shales, which are associated with the red, contain Obolella pretiosa. These
are the typical Sillery sandstones described in the Geology of Canada, 1863.

From Pte. a Pizeau the rocks of division 4 apparently strike diagonally
across the St. Lawrence and appear on the south side of the river at Point
Levis, where their characteristic red color serves well to indicate them. At
Levis these are succeeded by the rocks of division 5, which consist of
blackish green and gray shales with dolomitic limestone and limestone con-
glomerate. The black shales contain graptolites, and the conglomerates are
fossiliferous both in the paste and in the pebbles. These make up the bulk

LXI— Bull. Geol. Soc. Am., Vol. 1, 1889.

li',-_> i;. \\\ ELtS — STRATIGRAPHY OF THE "QUEBEC GROUP.

of what is known aa the Levis formation. It may here be remarked that
no rocks of division 5 have yel been recognized on t lie west or north side of
the river.

The red and green Bhales and greenish sandstones of division 1 are well
exposed on the south side of the St. Lawrence from Point I/vis to the
Chaudiere river, about seven miles distant, and for about seven miles further
on above that stream, to the village of St. Nicholas. Here they are terminated
by the fault which crosses from above Cape Rouge and brings the Hudson
River into view in an apparently underlying position. On the Chaudiere
they form a continuous section with a large development of the sandstone
portion from the mouth to the Grand Trunk railway bridge, in which section
several folds doubtless occur. Just below the bridge several sharp crump-
lings are seen, and in the green shales at the head of the great falls, three-
fourths of a mile below, as well as in those directly at the bridge itself, cer-
tain bands contain Lingula and Obolella in abundance. On this stream no
other fossils are found till we ascend to the vicinity of St. Bernard and St.
Lambert, where an overlying area of blackish and grayish shales contains
PhyUograptus and other graptolitic forms which indicate a basin of Levis
fossiliferous rocks underlain on either side by the shales of the Sillery.

From Point Levis the red and green shales are well exposed on the roads
leading southeasterly towards St. Henry; but a short distance below the
former place they are concealed by the graptolitic Bhales which constitute
the Lowesl portion of the Levis formation. A line of section running south-
east from the lower ferry at Levis, which is one mile north of Point Levis,
to the middle Levis fort, about a mile and a half distant, shows the rocks of
this portion arranged in a series of anticlinals, of which at leasl loin- are
clearly recognizable. Of these the most westerly is seen near the crest of
the hill overlooking the river at Levis, in a cutting on the road which then-
ascends to the upper town. The structure of this i- clearly an overturn.
The beds along the face of the cliff between this point and the old Victoria
Hotel at Point Levis show, by the crushed, faulted, and often overturned
character of much of the strata, the extension of the anticlinal in this
direction. Several of these anticlinals are indicated on the map and in the

-■ ■•lions published in the Alia- of 1 86 I by Sir William Logan, by whom the

outcrops of the several bands of limestone conglomerate were carefully
traced. The presence of the red shales of the Sillery formation in intimate
association with the fossiliferous L6vis beds was also noted, but these were
;ii thai time regarded as an integral portion of the fossiliferous series. This
i- a peculiarity of structure which now needs to be explained, and the cor-
rect interpretation of which reveal- very clearly the relative positions of the
two divisions.

CORRUGATED AND FAULTED STRUCTURE. 463

In order to determine this structure more closely, carefully arranged col-
lections of graptolites were made at various points along a line of section
extending from the south side of the St. Lawrence about half a mile below
the lower Levis ferry to Fort no. 2. On this section it was found that simi-
lar zones occurred at several places : First, at the river itself, in a cutting on
the line of the Intercolonial railway ; second, at the foot and in the face of
the cliff overhanging the road from Levis to St. Joseph; and, third, at the
city hall on the cliff in Levis. At all these places the dip of the beds is
very nearly the same, or southeasterly ; but between locations two and three
the extension of the overturned anticlinal already described is seen, and
shows that the collections from these places are, without doubt, from strata
of the same horizon, repeated on either side of the axis, while the structure of
the portion between the cliff and the river is really an overturned synclinal.

Tracing the courses of the other anticlinals which cross the line of section
to the southeast, these were found in all cases to be clearly indicated by the
occurrence of red shales which on following to the southwest become grad-
ually broader and merged into the great area of red aud green Sillery rocks
of the Point Levis and St. Henry section, on which line no fossiliferous
Levis anywhere appears. From the line of the Levis section northeastward
the Levis rocks gradually acquire a greater extent as we approach the town
of St. Joseph, though the anticlinal structure is still clearly visible. It
finally appears, therefore, that the Levis formation proper really occupies
the synclinal troughs or folds in the Sillery. These have a manifest dip to
the southeast, while to the southwest the Levis formation has been entirely
removed. In the extreme southeast of the section, the Levis graptolitic
shales with their bands of fossiliferous conglomerate appear, at first sight, to
underlie directly the great mass of the red and green Sillery shales and sand-
stones of the St. Henry section, and such was evidently the view held in
1866 ; but on examination of the trenches about the forts, constructed since
that date, this apparent superposition of the latter was clearly found to be
due to an overturned synclinal in the Levis beds, the outlines of which could
be clearly traced.

Along the coast, both on the south side of the islaud of Orleans aud on
the south side of the St. Lawrence, a similar structure doubtless exists; but
is complicated by a series of faults. On the island the Levis formation is
confined to a small area at the western extremity and brought into contact
with the Sillery shales by a line of fault, while the Sillery itself, often pre-
senting a wonderful series of folded aud crumpled strata, occupies the entire
south side of the island and the greater part of the south shore of the St.
Lawrence for several hundreds of miles eastward from Levis, or nearly to
the extremity of the Gaspe peninsula. Outcrops of strata holding Levis

464 E. W. ELLS — STRATIGRAPHY OF THE "QUEBEC GROl P."

graptolites ore found at but few points r i J ■ . 1 1 -_r this coast, among which may
be Doted a small area near Ste. A.nne dee Monts, and the extremity of Gape
I; ei< r at the lighthouse, when- L6vis forms have been obtained by Dr. Sel-
wyn and Mr. T. C. Weston. These are probably from an included band of
L6vis rucks in the Sillery, since the red and green shales and hard sand-
stones appear a short distance on either side of the point ; and it is from
this locality that the Dietyonema sovia/e recognized !>v Professor Lapworth
was obtained.

Tin. Succession about Levis and Quebec.

Tin 8tratigraphical StLCcewion. — In the study of the (Quebec group about
I/vis ami along the St. Lawrence much confusion has evidently arisen from
the neglect to distinguish the different zones oi Limestone conglomerate. Of
these, Beveral are now known to exist, the horizons or geological position of
which are entirely distinct. Areas of conglomerate, not, however, often cal-
careous, also occur in connection with the slates of the lower Cambrian
which flank the ridges of crystalline schist; but these need not here be
further described. Of those which occur in the unaltered Quebec group,
four well-defined zones are recognized.

The lowest division, which is of hut small extent, occurs near the base of
the Cape Rouge section and has not yet yielded fossils.

The second zone occurs with the Sillery rocks proper in connection with
hard quartzose sandstones or with shahs of different colors. They are well

d on the island of < Orleans, about two miles east of the hotel at the ferry
landing, and on the Beaumonl shore or south side of the St. Lawrence,
about four miles below Levis. They also appear at the extreme east end of
Orleans island and in several of the group lying in the river between this
island and Riviere du Loup, as well a- in connection with the quartzites on
the main land back from the coast, further east they are well displayed
about Bic and at other points on the north side of the Gaspe* peninsula.
These conglomerates are frequently coarse, with Limestone pebbles, often of
large size, which contain fossils of Primordial age, among which Olenellus
thompsoni i.~ abundant, while tl iated shahs contain Obolella and Borne

obscure graptolites. None of the forms from the L^vis shales have yet been
recognized among these, and they are, ;i- ;i group, distinct from those of the
mxt or Levis division. In the interior these conglomerates are also seen
near St. Sylvester and St. David, south of the Chaudiere river, where they
are also associated with red and green -hale- of Sillery aspect.

The third division iii ascending order comprises the LeVis conglomen
proper. These are clearly interstratified developments in the fossiliferoua
shales of that formation, ami contain a mixed fauna. Some of the pebbles

BULL GEOL SOC AM.

VOL 1, 1889, PL 10

QUEBEC

■St'Z. turrence Jti^er.
■Island. <xnct Quebec /•oitZt

1st Zone Oraptoli&es .

Tap of BUtfTo* Cliff JSLjinticiint
3r^orCtXyIfaZl band

2n^-^\nClclmr necu CutfioZCc Chitrch ,X>cvis.

Jryi^-tntictLne /tens- back street Levis.
\
fhslnt£cUrie West of Fort

Fort JVo 2, 3\5o ft above Hirer-
5thrA.nticluve JSast of Fart

Overlap of S tilery red Shales
onftossiliffcrotts S^cvis:

LOCAL CHARACTER OF THE CONGLOMERATE. 465

of limestone, which are also often of large size, hold an abundance of Pots-
dam forms, while others have large orthoceratites. The paste of this con-
glomerate contains fossils characteristic of the Calciferous formation, and in
places it is difficult to distinguish between the matrix and the pebbles them-
selves. These conglomerates are generally very local in their development,
and frequently form lenticular masses, surrounded by the characteristic Levis
shales. Much of the confusion arising from the study of these rocks has
been to a large extent due to the neglect in keeping clearly separated the
fossils of different horizons — i. e., those obtained from the bowlders and those
from the paste.

The fourth zone of conglomerates is that seen in the city of Quebec. These
are associated with the blackish bituminous shales and limestone of the
Citadel series, which have been found to contain a large fauna, embracing
graptolitic and other forms, presumably of Trenton- Utica age. These rocks
of Quebec city were formerly regarded as a portion of the " Quebec group "
proper, and the necessity for their separation was pointed out first by Dr.
Selwyn in 1877-78. The examination of the fossils from these strata by
Professor Lapworth and of more recent collections by Mr. H. M. Ami has
confirmed the views then advanced as to their later age, and they may there-
fore be considered as a somewhat peculiar development of strata intermediate
between the fossiliferous Levis shales and the Hudson River formation.

The Paleontological Succession. — The evidences already presented from the
stratigraphical standpoint as to the lower position of the Sillery formation
have been largely confirmed by the most recent determinations of the fossils
obtained from many points. The examination of these was entrusted to
Professor Charles Lapworth, whose conclusions were stated in a paper read
before the Royal Society of Canada in 1886. In this paper Professor Lap-
worth clearly recognizes three zones of graptolites, of which the first is
styled the Cape Rosier zone, or zone of Dictyonema sociale and Bryograptus,
and is regarded by him as representing probably a portion of the Cambrian
system. The second, or Ste. Anne zone, or that of PhyUograptus anna, includes
the great bulk of the graptolites from the fossiliferous beds of Levis and
vicinity. He regards this as newer by a well-marked interval than zone 1,
and as representing the base of the Ordovician or Cambro-Silurian system.
The third, or Ccenograptus gracilis zone, includes the rocks of Quebec city, the
north side of Orleans island and of the shore of the St. Lawrence below the
Marsouin river as well as other points, and is typical of a distinctly higher
horizon than the last, or probably that of the Trenton-Utica.

From this evidence it is plain that the fossils of zone 1, already obtained,
which include also the Obolella and Lingulce already referred to, and are
from a part of the red and green shale series of the Sillery, are assignable

466 K. W. ELLS — STRATIGRAPHY OF THE "QUEBE< GROUP."

to the Lowest place, and should be regarded as beneath those of the fossil-
iferous Levi- formation.

During the summer of 1889 the rocks about Quebec and Levis were ex-
amined with some care by Mr. C. I>. Walcott,of Washington. The pecu-
liar fauna- from the limestone conglomerates, both from the Sillery portions
on the Bouth side of Orleans island and from the Levi- formation at Levis
and >t. Joseph, were Btudied with some minuteness. The purely Cambrian
aspect of the fossils from the former was clearly recognized, while in those
of the Latter the Cambrian forms were found to be entirely confined to the
pebbles, the matrix of the rock being comparatively rich in fossils peculiar
to the Calciferous formation. The hands from which these mixed faunas
were taken were at the very base of the fossiliferous Levis series and almost
directly overlying the red shales of the .Sillery which were brought into
view along the denuded crest of one of the overturned anticlinals already
described, thus again confirming the sequence of strata and the relative
positions of the Levis and Sillery formations determined by the stratig-
raphy as stated in the preceding pages.

Conclusions.

I>riefly stated, then, the " Quebec group," as originally constituted. i- held
to he divisible into at least five distinct portions, in ascending order as fol-
low

1. A pre-Camhrian series, comprising the crystalline schists, limestones,
gneisses, and the associated dioritic, chloritic, and epidotic rocks which form
the axes of the several principal anticlinals.

2. A lower Cambrian series, composed of black, green, gray, and occa-
sionally purple slates, with hard quartzites, at times containing much quartz
in the form of veins, as well as through the mass of the rock it-elf. In it-
lower pari ii contains conglomerates holding pebbles derived from the under-
Lying series, and Berpentines are an important feature.

■'!. A.n upper Cambrian Beries, composed largely of red and green shales
with green and gray -ami-tone-, with which beds of lime-tone conglomerate
sometimes occur, the pebbles of which contain fossils of Primordial age,
while the -late- hold obscure graptolites, Lingula ami Obolella. The-.- rep-
ot what wa- formerly Btyled Sillery and Lauzon.

I. A N < trdovician or ( iambro-Silurian Beries, c imposed of black, graj . and
greenish shales, with bands of dolomite ami ana- of limestone conglomerate,
from the pebbles of which Potsdam fossils are obtained and from the paste
others of Calciferous age, the rock- occupying synclinals in the underlying
Silhry division. This is the Levis proper.

THE FIVE DIVISIONS OP THE "QUEBEC GROUP." 467

5. The Quebec Citadel series, also Cambro-Silurian, the horizon of which
is not yet definitely fixed, though the fossils from it have a distinctly Tren-
ton-Utica aspect and may represent a thickening of the lower portion of the
latter formation. These rocks are also seen on the island of Orleans at its
northwest extremity and for several miles eastward, as well as at various
points on the St. Lawrence. They are separated from divisions three and
four by well defined lines of fault.

These are succeeded upward by the fossiliferous Utica and Hudson River
or Lorraine shales, which are seen at Montmorency falls, Beauport, and
other places in the vicinity of Quebec.

2 ET N OF THE GEOLOG Ci. 80C ETV OF AMERICA

- ME ADDITIONAL EYIDE
bear:.

th; *al :

-;-:.-:.--.: i. - 7 . ; ::.-.:; 17. ?.i::."

PUBLISHED BY TH
Apeil, 1890

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA
Vol. 1, pp. 469-480. April 24, 1890

SOME ADDITIONAL EVIDENCES BEARING ON THE INTER-
VAL BETWEEN THE GLACIAL EPOCHS.

BY PRESIDENT T. C. CHAMBERLIN.*

{Read before the Society December 26, 1889.)

CONTENTS.

Page.

Limitation of the Statement 469

The Evidence drawn from the Lower Mississippi 469

The Evidence drawn from the Ohio and Allegheny Rivers 472

The Evidence drawn from the Susquehanna 473

The Evidence drawn from the Delaware 473

Conclusion 474

Discussion 474

Limitation of the Statement. — Evidences bearing upon the interval between
the glacial epochs may be drawn from various parts of the glaciated field,
and from the various phenomena connected with glaciation. It is not, how-
ever, my purpose to make any approach to an exhaustive review of these
evidences, or even to touch upon the arguments that may be drawn from all
the several sources. I desire simply to bring to your attention certain
specific evidences that have an important bearing upon the length of the main
interglacial interval, and that lend themselves more readily than others to
intellectual estimation. The evidences that are especially additional to pre-
vious knowledge are drawn from the lower Mississippi valley ; but, in con-
nection with these, I shall briefly refer to evidences drawn from other val-
leys that fall into marked harmony with them.

The Evidence drawn from the Lower Mississippi. — In the lower Mississippi
valley the sub-stratum consists of Tertiary deposits. Upon these there is a
thin stratum of gravel and sand, known heretofore quite widely as the
Orange Sand, although that term seems to have been applied to different
formations. This stratum has been very considerably misunderstood. It
does not contain, so far as critical investigation shows, any material that

* The facts relative to the lower Mississippi region are drawn in large measure from the observa-
tions of my associate, Professor R. D. Salisbury.

LXII— Bull. Gf.oi,. Soc. Am., Vol. 1, 1889. (469)

1:70 T. C. OHAMBERLIN — THE [NTERGLACIAL tNTERVAL.

may be regarded a< glacial, although I think in some of the earlier reports
Archean pebbles were cited as an indication that these gravels were con-
temporaneous with the glacial deposits of the north. They have been criti-
cally examined during the summer by my colleague, Professor Salisburyi
ami during the entire season's Bearch he has not found a single pebble that
is referable to a glacial origin. Some years since 1 examined the same
formation with the like result. Professor Call has also examined some of
these deposits with a similar result.' The pebbles are chiefly of chert, and
were derived from the chert-bearing limestones, which are Largely Car-
boniferous, but reach as far down as the Lower Magnesian limestone. They
are, therefore, non-glacial. This is a matter of some importance, as th
Bands and gravels have not only been correlated with the glacial deposits,
but referred to the Cham plain epoch. They are very far removed from
the Champlain deposits in time, and that correlation is one of the great
errors of Quaternary geology. They are certainly preglacial in the sei
that they were not contemporaneous with the glacial incursion at its earliesl
maximum. They may have been contemporaneous with the very earliest

_'-s of glaciation before the ice reached the Mississippi valley and was
able to mingle its deposit- with those of the valley.

Now these gravels occupy a wide area stretching across the basin of the
lower Mississippi from some distance back in Tennessee, Kentucky, and
Mississippi to the high lands upon the Arkansas side, appearing in the iso-
lated upland called Crowley's ridge, which bisects the present bottom of the
Mississippi. The gravel stratum undoubtedly was originally horizontal,
but it now undulates more or less conformably with the surface. Theex-
planation of this, it seem- to me, is found in the gradual creep of the sofl
material of the hills as they were slowly carved out by erosion. The brows
of the hills in some cases have obviously crept down the slopes, for on the
summits we find the gravels compact and firm and the constituent pebbles
lying with their maximum diameters in a horizonal position, while the stratum
has level upper and lower bounding planes. On the slopes of the hills.
however, the gravel beds are more or less broken up and the pebbles have

been disturbed and displaced and tumbled into various attitudes, such a- we

mighl naturally expect under the hypotheses of a creeping movement on
the slope. It seems impossible to suppose thai this stratum of gravel was
originally deposited in the undulatory form in which it is now found. It
mighl be supposed thai the Bill which overlies this gravel bed was deposited
:i- a mantle ,,v,r an undulatory Burface, but gravel does q >1 lend itself to
Buch a method of distribution.

The overlying mantle, which now chums attention, consists of fine silt and

embraces the loess deposits of the lower Mississippi. It Bpreads oul broadly

ravel Btratum and extends Bomewhal beyond it, especially on the

MECHANICAL CONSTITUTION OP THE LOESS. 471

east. This stratum is in places differentiated into two parts, separated by a
soil-like horizon. This differentiation is not common to the entire valley.
The silt mantle may be traced almost in unbroken continuity northward to
the border of the glacial drift, whence it spreads itself over the drift, reach-
ing over the drift surface some hundreds of miles to the northward. In this
northern stretch the silt mantle is correlated with a second episode of the
earlier glacial epoch. It graduates down into a stratum of bowlder clay
that overlies a bed of vegetable material, which in turn overlies another till.
Both of these tills I have been accustomed to correlate with the earlier glacial
epoch. I do not wish, however, to raise differences of opinion on that point
here. It is unimportant to the main conclusions which we desire to reach.

Besides this continuity, there is a further reason for regarding these silt
deposits as contemporaneous with the ice invasions.

They are made up in part of glacial particles — that is, particles derived
from the mechanical abrasion of the glacier. These particles consist of de-
composable silicates, dolomites, and limestoues and were rasped from rocks
of these varities lying further north. Such decomposable particles do not
abound in residuary clays but are abundant constituents of glacial clays.

It seems necessary to suppose that this mantle of loess and loess-like silt
was originally deposited as a horizontal stratum across the entire Missis-
sippi bottom and border land. At the present time it undulates over the
hills. At first thought it would seem that the depositing waters might have
been deep and the silt laid down as an undulatory mantle, but it would
seem necessary to extend the same hypothesis to the deposition of the gravels,
where its application is manifestly excluded by the nature of the deposit.
I feel sure from observation in certain cases that full investigation will show
this seeming mantling to be the result of the gradual degradation of the hills
accompanied by creep of the pliant and plastic material. This phenomenon
of creep has a wide expression, entirely independent of the area under con-
sideration ; but upon that I cannot dwell.

During the first glacial episode, the altitude and slope of the lower Mis-
sissippi basin were so low as to permit the deposit of this silt on bluffs which
are now 200 feet, more or less, above the present Mississippi bottom. Before
the second glacial epoch, according to the division I make, there was an
elevation sufficient to permit the erosion of the great trench of the lower
Mississippi by the predecessor of the present river. This erosion amounts
in round numbers to a trench about three hundred feet in depth and about
sixty miles in width. Some of the bluffs that are crowned by these silts are
200 to 250 feet in height ; and Professor Call's recent investigations show
80 to 100 feet of silt in the bottom. It is, therefore, I think, safe to say that
in round numbers there was an erosion of the magnitude named reaching
from Cairo south to the Gulf, with corresponding erosion trenches along the

U'l T. C. I EA.MBERLIN — THE INTERGLACIAL INTERVAL.

upper branches during the interval between the two epochs. This great ero-
sion represents the interval between the formation of the silt< of the earlier
glacial epoch and the filling in of the valley deposits of the later glacial epoch,
which now demand our attention. If we go hack on the glaciated area to the
moraines which mark the limit of the later glacial incursions we find, start-
ing from the outer side of these moraines, valley streams of gravel formed
contemporaneously with these ice incursions. Tracing these gravel streams
along their courses we find that they run down into and partially till the
channels cut in the interglacial interval. On the upper Mississippi, on
the Chippewa, on the Wisconsin, and on other tributary rivers we find
gravel trains heading on the outer edge of the outer moraine of the later
epoch. Passing down through the interglacial trenches there are found
represented in the lower Misssissippi valley (as I think we may safely say
from recently gathered evidence) equivalent deposits in the bottom of the
Mississippi overlain, of course, by the more recent deposits. The work of
the earlier glacial epoch in the lower Mississippi I conceive to be the deposit
of the loess and loess-like silts ; that of the interglacial epoch the erosion of
the great trench in which the Mississippi bottoms now lie; and that of the
later glacial epoch the partial filling of this trench. The trenching is
the measure of the interglacial interval, or at least is a partial measure of it,
Tfu Evidence drain/ from the Ohio and Allegheny Rivers. — if we pass
to the upper Ohio and Allegheny valleys we find phenomena that fall
into close correspondence with the foregoing. There are high shoulders
and terraces at various points which bear upon themselves glacial river
gravels. One of the most decisive, found in the vicinity of Parkersburg,
has been described by Mr. Chance and others. Here an old channel runs
hack from the present course and, curving around a group of hills, returns,
forming an "ox how." In this old channel, glacial river gravels are found,
showing that it was occupied contemporaneously with some stage id' the
glacial period. This abandoned channel is about two hundred feet above
the present Allegheny river. Mr. Chance tells us there is about fifty feet of
drift in the presenf valley bottom; so between this upper river bed and

the bottom of the present rock bed there is evidence of an erosion of 250

feet, two hundred of which, in round numbers, are cut through Carboniferous
Btrata. Similar and corroborative facts show themselves along the course

of the river above and below, and along the Monongahela and the upper
Ohio.

[f we trace the old channel of the Allegheny northward by means of
remna .1 shoulders and terraces, we find that it lies considerably above the
altitude of the terminal moraines of the later epoch, anil also much above
the gravel t rain- that head on the outer side of these moraines and run down
through the trench above indicated. Ii therefore becomes a necessary in-

EARLY GLACIAL PLAINS TRENCHED BY INTERGLACIAL VALLEYS. 473

ference that the trench was cut before the moraines were pushed across it,
and before the moraine-derived gravels could be carried down into it. The
trench therefore represents the interval between the earlier and the later
glacial epochs. I have placed in manuscript elsewhere the fuller facts
upon which these brief statements rest, and they will appear in print in
time.

The Evidence drawn from the Susquehanna. — If we pass over the Susque-
hanna valley we find like phenomena. These have been brought out by
Mr. McGee and others, and I need only refer to them because of their con-
nection with that which I have already presented. Here we find old benches
covered with rounded pebbles — some of which are glaciated — reaching to a
similar height of about 250 feet above the present Susquehanna river.
There are glaciated pebbles at higher altitudes, but I have taken the more
moderate figure because it is a safe one. Near Sunbury glaciated stones
were found by Professor Salisbury about six hundred feet above the present
river. Below these high terraces, and in the valley excavated out of the
plain from which they were derived, we find a lower terrace sixty or seventy
feet in height, of newer and distinctive aspect. Above Berwick this lower
terrace connects itself definitely with the terminal moraine, which there
crosses the river. The terrace rises rapidly as it joins this moraine, as is
the habit of moraine-headed terraces, and reaches an altitude of 100 to 150
feet as it merges into the moraine. But it is still much below the old ter-
races, from which it is sharply distinguished by its freshness and other
marks of youth and by its constituent material.

It appears therefore that at this point a deep trench was cut in the flood-
plain of which the old terraces are the remnants before the formation of the
later moraine and of the valley deposits that sprang from it.

The Evidence drawn from the Delaware. — If we cross the Appalachian
crest to the Delaware valley we find analogous facts, which are more famil-
iar through the writings of several geologists. Many years ago Professor
Lewis called attention to the earlier and later deposits of that region, though
he did not give them the interpretation I shall place upon them here, which
coincides essentially with that of McGee. As we follow up the valley toward
Belvidere, where the moraine crosses the Delaware, we find old terraces
reaching up to about 240 by 250 feet, upon which are rounded pebbles and
glaciated stones, indicating an origin in the earlier stage of glaciation. Cut-
ting through these old plains and the rock below we find the deep trench
in which the later deposits have been placed. These later gravel deposits
originating with the moraine at a height of somewhat above 150 feet, rap-
idly decline to about 85 feet a few miles above Lewisburg, opposite a point
where the older terrace rises to about 250. The measure of the interval
here is some 250 to 300 feet of rock-cutting.

1,1 T. C. CHAMBERLLN — THE [NTERGLACIAL INTERVAL.

Conclusion. — It would appear, therefore, that while there are local varia-
tions there is a general correspondence between the amount of erosive work
done by the lower Mississippi, by the upper Ohio and Allegheny, by the
Susquehanna, and by the Delaware rivers respectively. The facts indicate
that the altitude of the continent was low in the closing stages of the earlier
glacial epoch; that it became higher in the'interglacial interval; and that
after sufficient time elapsed for these great erosious to take place, the glacial
water.- of the later epoch poured their valley deposits down the trenches formed
in the interval. The cutting of these trenches rudely measures the length of
this interval, or at least the length of the actively erosive part of it.

DISCUSSION.

.Mr. W .1 McGee: President Ghamberlin remarks that the orange sands
of the south are largely preglacial or Tertiary. Now " Orange Sand " is
the name of a series of dep »sits grouped and so designated many years ago
by Professor E. W. Hilgard. That series really includes deposits of widely
diverse ages: Beginning with the newest, it includes certain Pleistocene
or glacial gravels forming the basal member of the loess; it includes also
the gravels of a wide-spread deposit elsewhere termed the Appomattox forma-
tion; it includes, too, certain gravels and loams which are early Cretaceous,
or possibly Jurassic — the Potomac formation, or the Tuscaloosa of Smith
and Johnson. In addition to these deposits of definitely determined ag
it includes a variety of residuary gravels and Loams which extend from the
present hack to the close of the Jurassic. By far the greater part of the
"Orange Sand" consists of materials properly included in the Appomattox
formation, and the greater pari of the remainder consists of materials
which are earlier than Pleistocene. But I desire to call special attention to
certain Pleistocene gravels, heretofore classed with the "Orange Sand,"
which it seems to me that President Chamberlin has overlooked. They
occur in part- of the lower Mississippi region, uotably in the neighborhood
of Vicksburg and Grand Gulf, Mississippi. There may he found a magnifi-
cent developmenl ofloess, which is charged with fossils and is in all respects
so characteristic that these localities may he regarded a- typical for the
loess of tie- North American continent. This loess rests ou the gravel in

qU68tion. Now careful examination -how- that the loess and gravel are not

unconformable, a- hitherto supposed, hut that the one graduates into the
other. This in tergradation takes place by interstratification ; the loess firel
becomes sandy al the base, and then becomes interstratified with silts; and
-till lower the loess appears only in thin layers interbedded with silts, loams,

-and-, ami finally gravels. Thi- stratum of tran-iti nay he 10 or 15 feet

in thickness; hut there is absolutely imperceptible transition by interstrati-

DISPLACEMENT OF THE LOESS AT VICKSBURG. 475

fication from loess above to gravel below. I dwell upon the point because
the relation is not the one commonly seen. In the neighborhood of Vicks-
burg on the banks of the Mississippi, where the bluffs are two hundred feet
high, the loess commonly appears to rest unconforinably on the gravel. The
former is charged with fossils down to a plane of contact as smooth as a
floor for hundreds of square yards ; and below that plane there is nothing
but gravel — stratified and cross-bedded gravel, which President Chamberlin
has well described as consisting of chert with no far northern material. But
the apparent unconformity has been produced — and the statement is made
with hesitation, because it sounds incredible — by movements within the body of
the formation since it was laid down ; and in some of the better sections in
the neighborhood of Vicksburg the character of the movements is illustrated.
At one extremity of the best section about Vicksburg (half a mile south of
the National Cemetery), the loess and gravel intergraduate as already de-
scribed ; while at the other extremity of the section the usual unconformity
appears — the loess resting upon the smooth surface of a gravel bed ; but at a
point between, a line of fracture cuts off the transitional beds of sand, silt,
loam, and fine gravel normally lying between the loess above and the gravel
below, indicating either that the stratified beds have been squeezed out, or
that the loess has slipped down upon the gravel surface from a higher level.
In short, about Vicksburg, there have been landslips of enormous extent,
and these landslips have produced the prevailing unconformity. The struc-
ture finds expression in a wide-spread but peculiar surface configuration :
There are many areas of plane surface one to three miles in extent which re-
mind the geologist at once of fluviatile or littoral terraces; but no two of the
planes rise to the same level, and, while all are inclined more or less, no two
incline in the same direction or with the same slope ; consequently there is
a series of unrelated terraces sculptured into hills and ravines yet retaining
indications of original attitudes, running over great areas. Thus the whole
structure of the Pleistocene dejmsits in the vicinity of Vicksburg and Grand
Gulf, and the whole topography as well, are affected by a series of landslips.
The point of present importance is the fact that the loess and gravels to-
gether constitute a distinct structural unit. The loess graduates downward
into the gravels, and these gravels are Pleistocene; and both represent glacial
action, unquestionably during the earlier ice invasion.

President Chamberlin : I think I understand what Mr. McGee refers to.
The same phenomena may be seen at Randolph, at Fort Pillow, and on
Crowley's ridge. I referred to it hastily, and it is not strange that Mr.
McGee should have misunderstood me. At Fort Pillow and at Randolph
there are beautiful sections. There are the Tertiaries at the bottom, and
then these gravels 8 to 10 feet, more or less, in depth. These graduate, as
Mr. McGee has said, up into a silt. This silt ranges up to 8 or 10 or more

176 T. C. ■ II Wir.l i;l IX — THE INTERGLACIAL [NTERVAL.

fl <i in depth. The upper pan of the silt becomes dirty in color, and at the
top there seeme to be a char demarkation from an upper silt. Thia dark,
Boil like band seemed to Professor Salisbury and myself to clearly indicate
an ancient Burface. Now, thai silt,in thai region at least, does not contain
any of the characteristic fossils at least they were not found by us : mo
far as we know, does it show any microscopic peculiarity which indicates its
origin. It remains with us an open question whether this belongs to the
glacial series or not Our prepossessions are strongly in the affirmative, be-
cause we have two formations at the north for which we wish to find equiva-
lents in thai southern region, namely, the lower till, to which I referred in
my paper, and the upper till, to which I also referred. We find further
north, in connection with each of these till>, loess-like surfaces, and have
been searching in the lower Mississippi valley for their equivalents. If we
find thai the lower Bill is glacial, we have what we Beek. The interval I
described was subsequent to the formation of both these silt series. You are
aware that Mr. McGee insists upon there being a long interval between the
two silts. I concede that But it seems to me that the later interval was

eater than this. That is .-imply a point of difference of opinion. The
erosion measure 1 have described is applicable to the later interval. There
is no difference between us whatever as to the facts upon this point at least,
hut there i- a difference of interpretation.

Mr. d. K. Procter: [n addition to the information derived from President
Chamberlin's paper, I have come to Borne knowledge of the (acts in regard
p. the "Orange Sand." My observations in western Kentucky and Mis-

-ippi are that the pebbles of that deposit run up into the loess for four or
live feet, LT't i i dlt Bmalleras we rise above the horizon .,f the Orangi Sand.
I have found in the Orange Sand at Hickman, Columbus and Paducah
-ilieiiied fragments of the rock- of the Mississippi valley, as well a- Trenton
fossils, not very much worn. It i> mostly made up of pebbles and cherl
from the lower < larboniferous, and on the western holder we have islands of
chert, much worn down, in which the cherty fragments are angular and
sharp, and that same chert is found interstratified with the lime-tone.- on the
eastern border of thi si r< c< nt formations : but as we Lret nearer to the Mis-
sissippi river and further away from the Carboniferous rocks these angular
ami -harp cherts become more rounded and worn, and I believe that this
same ( 'range Sand deposit is traceable all the way up the Ohio river to the
mouth of the 1 1 3 indy, partaking more and more of the character of the
northern rock a- we go northward. I found the same deposil on Sandy
river, hut a- we gel into southern waters of thia and other Kentucky Btreama
we find in thi- gravel deposit (which is in the " second bottoms," or above
the high water of the river | no evidences of northern rocks. This i- true
the -ravel- of Kentucky river, the Sand} . and the Licking ; hut immediately

THE OHIO AND MONONGAHELA RIVERS, iti

along the waters of the Ohio, where we find the same gravel, we find tl
debris of northern rocks at almost the same level. The- gravels take the

slope of the river, so that we find them at 300 feet above tide at Hickman
and reaching up to 700 feet above the sea further up the river ; and they are
covered all the way, with very Blight interruptions, with the silt formation,
which may be traced almost to the very head-waters of the stream, partak-
ing of the character of the rocks of the several water-courses. The silt
formation is sometimes a loam, and I believe it is traceable all the way down
to the loess covering the Orange Sand deposits of the lower Mississippi
valley.

Mr. F. J. H. Merrill: I should like to say a few words in regard to the
interglacial deposits of the Delaware. The region south of the moral
near Belvidere has been discussed as a type area. There is a here a broad
plain, over 200 feet above the river, which is covered with loam, and under-
neath which is a certain amount of gravel ; this comes up to the margin
of the moraine at about 460 feet above tide and about 260 feet above the
river. There are evidences of moraines, and there are also small gravel
deposits indicating that a body of water stood on the southwestern margin
of the moraine, and that this great plain along the Delaware river and val-
ley was filled with a body of water, either a lake or an estuary. I want to
ask President Chamberlin how, in a valley which has been filled with water
subsequent to the formation of the moraine, we are to di- . ish glacial
material that might have been deposited in the water that filled the valley
from any glacial material that might have been laid down in that valley
before the moraine came into existence? There are evidences that this val-
ley of the Delaware at the southwestern margin of the moraine was filled
with water to a height of about 460 feet above tide; and I am anxious to
know if there is any test by which the later glacial deposit can be differen-
tiated from the earlier one under the conditions I have mentioned.

Professor I. C. White : The facts presented by President Chamberlin from
the valley of the Ohio have always been interpreted differently by other geol-
ogies who have studied that region. There is everywhere along the vail' -
of the Monongahela and Ohio evidence of submergence, and the question
which has just been asked is very pertinent. How are we to discriminate,
or what test shall we employ by which we can recognize the difference be-
tween glacial material brought down by the water from these northern
moraines and distributed all along the valley and that brought down by the
ice ? Now, my observations in the. Monongahela valley have shown that
we have an area extending over hundreds of square miles covered with cla -
showing unquestionably that deposits were made in water. These clays
mantle the hills where the surface is not b - and they extend up
about 1,100 feet above the sea. I have during the present summer made a

LXIII— Bru - :. Am., Vol. 1, I

478 T. C. CHAMBERLIN — Till: [NTEBGLACIAL [NTERVAL.

discovery with reference to these dep isits which connects those of the valley
of the Ohio with those of the Monongahela valley. Any of you who travel
along the Parkersburg branch of the Baltimore and < >hio railway will observe
that west of Clarksburg the railway crosses a summit. On one Bide the
water drains into the Oh in. and on the other into the Monongahela. It is a
broad, level Bummit, having an elevation of 1 ,100 feet, in a gap of probably
300 feel below the enclosing hills. Thai gap, or valley, is covered by a
deposit of fine clay. The cut through it is about 30 feet : and one can observe
the succession of clays of all kind- ami of different colors, from yellow on the
Burface down to the finest white potter's clay at the level of the railway
where the cut reaches bed-rock, thus proving that the region has been Bub-
merged. This submergence would carry a water-level up the Allegheny
valley into the region to which President Chamberlin refers, ami would
satisfactorily explain the phenomena there without recourse to a "second
glacial epoch," where the evidence of neither a " first " nor a " second " ever
existed.

President Chamberlin: It. is the work of the geologist to distinguish
between the deposits formed by water running on a slope and those formed
by static or horizontal waters. These differences are char and sharp when
the formation- are well developed, and are capable of p isitive discrimination.
[n respect to the deposits on the Allegheny and Monongahela and upper
Ohio, to which reference has been made, I may say that several years ago
Mr. Gilbert and myself spent more than twenty days on this especial problem
of discrimination, and satisfied ourselves completely that they were formed
l>y running water, as I think Mr. Gilbert will say if an opportunity is
afforded. Mr. McG se has made similar observations on the deposits of the
upper Delaware and Susquehanna, and so has Professor Salisbury : and I
may say the same in reference to my own convictions regarding these river-.
In the case of the Allegheny and the Monongahela, taken together, the
facts are sharp and well defined, and 1 may make that case typical in my
answer. These terraces on the Allegheny and Monongahela rivers arc not
distributed in horizontal lines along the -lopes of the valley as if they were
formed by the stationary water by means of wave action on the valley Bide.
~ oh wave action should be nearly uniform throughout the whole length,
•pi as long stretches or coincidence with the direction of the prevailing
wind- gave greater fore.'. There are certain characteristic inequalities in the
cutting of terraces by a body of stationary water, hut the laws and the
characteristics are well known, having been very beautifully and Bharply
brought out by those who have investigated the deposits of the western region.
On the other hand, the work done by streams is radically different. The
cm- wherever in it- meanderings it strikes with greater force, and
leaves such portions as happen to lie in its concave curves. The resulting

PRINCIPLES OF DISCRIMINATION OF AQUEOUS DEPOSITS. 479

terraces are radically different from shore terraces. Again, the terraces of
static water must necessarily be horizontal, and must remain so except as
crust flexures distort them. Now, in the Monongahela valley, as was said
many years ago by Professor Stevenson, the terraces decline from the south
towards the north. The terraces on the Allegheny river slope south towards
Pittsburgh. Those of the Monongahela slope north towards Pittsburgh. Now.
this is just what we should expect in the case of rivers, but not in the case
of lakes. Some of these terraces are rocky shelves, as long ago shown by
Professor Stevenson and Professor Chance, who have put correct interpreta-
tions upon the phenomena. These rocky shelves extend sometimes nearly
half a mile back. Below Pittsburgh one is described by Professor Wright,
in exemplification of the submergence theory just mentioned. He states that
the shelf is cut back half a mile in the rock. Now, imagine the time requisite
for the cutting back of half a mile on one side of the river yet practically
nothing on the other side! Again, take the case where a valley passes off
among the hills and returns, forming an " ox-bow." Here we have phe-
nomena that do not lend themselves at all to the lacustrine hypothesis. And
so, again, if you turn to the material it will be found to be of the kind
produced by onward-moving water rolling the pebbles over and over again, •
rather than by a to-and-fro action which slides 'the pebbles and gives a dif-
ferent form. The discrimination is not as sharp and clear as in the other
case, but is still capable of being made. There are other facts lying in the
same line.

I am unable to discuss the evidences of the submergence about Belvidere,
because I did not see such evidences. Some of the later terraces are made
up of well-rounded fresh gravel, without any depth of silt upon it. Now,
if these had been submerged, the greater part of the silt would have been
on these gravels and the moraine itself. All of these terraces are evidences,
it seems to me, of land conditions since the formation of the later glacial
deposits.

Professor White : I agree perfectly with President Chamberlin that these
benches which slope downward were the result of erosion, but I claim that
subsequent to the erosion of these benches all of them were covered with
lacustrine deposits. The proof of this is found in the fact that along the
Monongahela and its tributaries there is at the summit of this lacustrine
level a deposit of clays and bowlders and erosion debris of every description,
beginning at 1,100 feet above sea level and extending down to the present
flood-plain. Now, on the Baltimore and Ohio railway there is, it seems to
me, an absolute proof of this submergence, because the old valley slopes there
on the one hand into the Ohio, and on the other into the Monongahela, and
yet the the summit has thirty feet of a clay deposit; and on this summit,
and on other tributaries of the Monongahela, these clay deposits cease at

180 T. C. « HAMBERLIN — THE [NTERGLACIAL [NTERVAL.

altitudes of 1,075 to 1,100 feet, and above that level there is no deposit —
there is simply the decomposed shale and rocks in place. Why should these
clay deposits cease near thai prescribed level if there has been no submer-
gence during the later history of this valley ?

Mr. McGee: To correcl a possible misapprehension, I beg to say thai the
point which I raised a few moments Bince is an altogether subordinate one.
Id regard to the general subjecl of President Chamberlin's communication,
I am in perfect accord with him; and having gone over very much of the
ground he has described, I can testify to the correctness of his statements oi
fact. And I should Like to add that I consider bis communication an •

dingly important < tribution to the complex Bubject of Pleistocene his-
tory.

Wiih respect to the phenomena aboul Belvidere, I desire to add a
word: I have been on the ground; I am familiar with the nice of the coun-
try; I have studied the moraine with its overwash terraces, and the more
impressive terraces upon which the moraine was pushed, and bo I speak with
some confidence concerning the phenomena. <)n the outer Bide of the
moraine lie the early Pleistocene Columbia) terraces, one of which must
be fully two miles in width and four or five in length, constituting the great
topographic features of the region. On the other side of the moraine and
along its Blopes there may be oewer terraces, but if so they are bo .-mall that
they escaped my observation, although I traversed the ground in search of
jusl such phenomena.

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA

VOL. 1, PP. 481-500; PLS. 11-13

THE CUBOIDES ZONE AND ITS FAUNA ;
A DISCUSSION OF METHODS OF CORRELATION

HENRY S. WILLIAMS

WASHINGTON

PUBLISHED BY THE SOCIETY

May, 1890

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA
Vol. 1, pp. 481-500, pls. 11-13 May 7, 1890

THE CUBOIDES ZONE AND ITS FAUNA; A DISCUSSION OF
METHODS OF CORRELATION.

BY HENRY S. WILLIAMS.
{Read before the Society December 28, 1889.)

CONTENTS.

Page.

Introduction 481

The Principles of Correlation 482

The Cuboides Zone 485

The Cuboides Fauna ^ 48G

The Frasnien Fauna of Gosselet 488

Homotaxy and Contemporaneity 489

The Tully Limestone and its Fauna 489

Comparison of New York Species with European Forms 492

Comparison of European Species with American Forms 494

The Transition between the Hamilton and the Tully Faunas 490

Review of the Argument 498

Conclusion 498

Discussion 499

Introduction.

Geologists are well acquainted with the fact that during certain portions
of geologic time, through a system, or several systems it may be, the rocks
for a considerable region may indicate conspicuous uniformity in their geo-
logic history. Thus, the Appalachian basin, as it is called, extending from
New York to Alabama, and several hundred miles in width, presents in all
essential features great uniformity in the nature of the deposits, in their
order, and in the sequence of the faunas for the large part of the Paleozoic
time.

When, however, comparison is made of sections in widely separated regions,
as those of Nevada and New York, although the general sequence of faunas
is similar, the details of the geologic history, as recorded by the stratigraphic
series, are entirely distinct.

In the first case, whatever differences are recorded in different pails of the
region, may be directly correlate! by the intermediate sections, and each

LXIV— Ruix. Gf.oi,. Soc. Am., Vol. 1, 1889. ( 181)*

ds"J II. S. WILLIAMS — THE CUBOIDES ZONE AND ITS PAUNA.

geologic period over the whole region may be regarded as recording approxi-
mately contemporaneous events, and their faunas as living at the same time.
In the second case, evidences may be gathered to correlate the two series
within broad limits: but when a wide ocean separates the two sections, corre-
lation of the subdivisions of the grand systems of geology is in a high de-
gree hypothetical, and though in text-hooks and systematic works it may be
pardonable, for practical purposes it is of very little value.

But the geologist, and particularly the paleontologist is constantly called
upon to compare the geologic history of different continents; and while it
has become apparent that each continent must have its own standard scale
of geologic uidts, it is also of great importance to find, if possible, some
points in the several standards where precise correlation is practicable.

The following paper is an attempt to establish such a point of contem-
poraneity in the standard geologic time scales of Europe and America for
the upper Paleozoic.

In the preparation of this paper the facts regarding the rocks and faunas
of New York are derived from personal examination and from notes and
collections made for the United States Geological Survey by Mr. Ira Sayles
under my direction. For the facts regarding the foreign Devonian I am
indebted, for England, chiefly to the works of Murchison, Phillips, David-
son, Etheridge, Sowerby, T. M. Hall. \Y. A. E. Ussher, G. F. Whidbourne,
and to personal examination of the collection- of the last three gentlemen
and those in the Jerniyn Street and South Kensington Museums, and of
the sections of North and South Devonshire; for continental Europe and
Asia to the works of Kayscr, Barrois, Gosselet, Dewalque, Mourlon, Oeh-
lert, C. F. and F. A. Etoemer, Geinitz, Schnur, Grunewaldt, Keyserling, —
Murchison, Verneuil and Keyserling, — Tschernechew, Venukoff, von Eticht-
hoi'eii ; but especially to the writings of Emanuel ECayser, whose critical
Studies of the Devonian fossils of both EDurope and Asia are invaluable.

THE Pimm iri.i .- OF CORRELATION.

In discussing geologic formations of different regions of the earth, the
logisl requires a method of classification of terranes and a system of notation.

The classifications in use are those based I 1 I upon the mineral constitu-
tion or structure of the rocks, (2) on their stratigraphic sequence, and for
sedimentary rocks (3) on their fossil contents.

For the normal sedimentary rocks I which alone are discussed in tin- paper)

correlation of t wo separate terra ne-. ha- 1 n attempted, first, by comparison

of the constitution of the rocks themselves. This method, except for lim-
ited areas, i- unsatisfactory, other evidence having conclusively Bhown that

CONDITIONS OP PALEONTOLOGIO CORRELATION. 483

a continuous terrane may vary in its constitution, in the fineness or coarse-
ness of its constituent particles, or in its composition, in the course of a few
miles' distance. Second, stratigraphic sequence is a reliable guide in corre-
lation when the individual strata of two corresponding sections are certainly
identified. But it is known that two separate sections through correspond-
ing parts of a terrane may vary considerably — gaps in one may be filled
by important strata in another, and strata thick in one section may be thin
and insignificant in another. The third means of identifying individual
strata, as well as general terraues, is by the contained fossils.

Fossils, as well as mineral constitution, present local variations in strata
known to be continuous. Geologic correlation at its best is but approximately
correct wherever widely extended areas or separate districts are concerned,
because the means of correlation are not constant.

Sequence, or order of succession, is the fundamental principle in all geo-
logic classifications of sedimentary deposits, but the two groups of criteria
(lithologic strata and organic species) whose succession is studied are of
different natures, and their variations are due to different causes.

Each geologic stratum was originally a sedimentary deposit ; hence strata
vary with the differences in the original conditions of sedimentation and in
the source of the sediments deposited. In consequence, geologic time has little
or nothing to do with the lithologic character of the strata. A Cambrian
sandstone of one region may not differ essentially from a Tertiary sandstone
of another region, and the representative of a Cambrian sandstone of one
region may be expected to be a limestone in another.

Since, then, the nature of the deposit must depend upon the local condi-
tion of the source of materials and upon conditions of sedimentation, there-
fore close similarity in the nature of sedimentation or in the sequence must
necessarily be more or less local, and correlation by this means will be less
and less reliable the more distant the two correlated sections are from each
other.

Fossil species, on the other hand, are the remains of organisms which once
lived, and of living organisms we know that they are more or less depend-
ent upon conditions of environment ; that animals or plants are adapted to
air, land, fresh water, or salt water ; to differences of environment due to
differences of temperature, moisture, height, depth, etc. Faunas and floras
also differ, other things being equal, coordinate with geographical distribu-
tion ; and, most prominently of all, differences are seen in the faunas and
floras of each successive stage in the geologic history of the whole world.

Successive strata, then, may contain (a) the faunas of successive ages, or
(6) the faunas of varying depths of ocean, or (c) the faunas whose geographic
distribution has shifted; and correlation by means of fossils is liable to
error from confusion of these causes of difference.

M II. S. WILLIAM Till: CUBOIDBS ZONE AM> ITS FAUNA.

AJso, ihf Bame species may indicate likeness of conditions which, though
shifting geographically, may have continued through the time indicated by
a considerable oscillation of the conditions <»f deposition. Two species, or
two fauna- made up of entirely different species, may indicate only difference
of environment, although of precisely contempora >us period.

Bui according to our present knowledge, it appears to be positively cer-
tain thai organisms have changed for the whole world more or less rapidly
and completely with the progress of geologic time This being the ease, if
we could ascertain the laws of change as expressed in the several orders and
genera of organisms we would he able to determine by them the geologic
period at which the deposits containing them were made.

[f organisms remained constant under all conditions of environment, or if
their differences due to changed environment were of a different nature
from those coordinate with continued reproduction, we might use them to
determine actual contemporaneity of strata ; but this is not the fact.

It is a fact that the characters which present a degree of constancy
among closely related forms of two widely separate areas are also in like
degree COnstanl for a relatively long time geologically. On the other hand,
characters which in series of closely allied species are constant for only
limited areas, their variation- constituting differences between the species of
separate regions, are also different for the species of each successive geologic

.-t:i_

Hence, in the use of fossils for purposes of correlation, it happens that a
knowledge of the habits, history, laws of constancy ami of variation of each
species and of the genus to which it belongs are essential 'lenient- iii the
problem.

The mere identity of some species in two compared formations, or even
identity of genera with closely allied Bpecies, is not alone evidence of con-
temporaneity. And in this respect, no doubt, the application of the term
hoTnotaxy to such similar formation-.;:- proposed by Huxley, is preferable
to conU mporaneity.

Winn, however, we consider the fact that all groups of fossils, when
Btudied comparatively and with a view to ascertaining their historical muta-
tions, do presenl regular modifications of some of their characters coordinate
with geologic sequence, the question is raised whether fossils may not pre-
sent intrinsic evident fthe position they may occupy in the lite history of

the '.''-nil- to which they belong. In the belief thai this i< possible, I have
mail'- :in exhaustive study of a fauna which, in Germany, Prance, Belgium,
England, Russia, and eastward, is found between typical middle and upper
Devonian fauuas, and I have compared with it a fauna occurring in New
York in what is called the 'fully lime-tone. In the following discussion I
-hall endeavor to point out the nature of the evidence by which it seeme pos-
sible to determine relative contemporaneity of strata by means of fossils.

The Cuboides Zone.

For several years I have been seeking some point in the upper Paleozoic
series of Europe and America at which precise correlation might be possible.

It is difficult to find an American Devonian species which does not differ
as much from its closest European representatives as it does from its nearest
allies in the formations below or in the formations above its normal horizon.
Therefore, correlation by mere numerical comparison of lists of fossils must
be regarded as having a normal error of at least the length of an ordinary
geologic age, or etage, as those terms are used by the International Congress
of Geologists.

The sharpness of definition of the fauna of our Newr York Tully limestone
at the base of the upper Devonian, when it is not confused with the Hamil-
ton fauna below (as it has frequently been), led me to select it for special
study. It is directly comparable with the " Cuboides Schichten " of Emanuel
Kayser, who has done more than any one else to classify the formations and
faunas of the Devonian rocks of Germany.

The name "Cuboides Schichten" was applied by Kayser to the calcareous
shales and argillaceous and nodular limestones of Aachen (Aix la Chapelle)
and of the Rhenish provinces of Prussia, which immediately follow the
Stringocephalus limestone.* Across the border in Belgium they are called
by Gosselet f the Frasnien limestone and shales ; in the Harz it is the Iberger
limestone.

For this northern part of Europe the Devonian history of sedimentation
was, first, coarser deposits, sands, and, in some cases, conglomerates, with
frequent evidence of volcanic disturbance marking the lower Devonian and
beginning of the middle Devonian periods, followed b}r limestones, thick and
massive, in the Eifel ; in other regions often associated with calcareous shale
and argillaceous shale, and in the upper part purer limestone, as at Pelm
reaching great thickness — over a thousand feet — and characterized by the
presence of String ocephalus burtini.

This String ocephalus limestone is recognized in the Eifel district, in the
northwest Harz, in Nassau and Westphalia, and in southern Belgium and
northern France. It is the Givetien limestone of Gosselet and Dewalque.

Above the String ocephalus limestones follow impure limestones or calcare-
ous shales (the German Mergel), called by C. F. Roemer £ Verneuili Schiefer,
and by F. A. Roemer,§ in the northwest Harz, Iberger Kalk and Goslarer
Schiefer — the Frasnien of Gosselet aud the Belgian and French authors.

* Emanuel Kayser: Das Devon der Gegend von Aachen, Zeitschr. d. Deutschen geologoschen
Gesetlschaft, Jahrg., 1870, p. 848.
t M. J. Gosselet : Esqnisse Geologique du Nord de la France, 1880, fasc. I, p. 95.
JC. F. Roemer: Das Rheinische (Jebergangsgebirge, 1844.
f F. A. Roemer: Beitriige zur geologischen Kenntniss des Nordwestlichen Harzgebirges, 1850.

(485)

186 II. S. WILLIAMS — THE CUBOIDES ZONE AND ITS FAUNA.

Iii the Hi Mian and similar sections it is the Cuboides Kalke and Mergel or
merely Ouboides Schichten of Kayser. These again are followed by shales
and sandstones and occasional impure limestone.

In the transition from the purer Stringoeephalus limestone to the coarser

upper Devonian sandstones, the first stage is that of the argillaceous lime-
stone (or MergeV), containing the Cuboides fauna; second, a fine-grained,
often black and occasionally concretionary shale, containing Gonial iff* very
generally, and frequently having few fossils and those small, among which
is the Cardiola retrostriata. Above these are the Cypridinen shales and
sandstones and occasional limestones with the later Devonian faunas.

The Cuboides Fauna.

The principal fossils of the Cuboides Schichten, according to Kayser,* are —

Rhynchonella cuboides, Sowerby.
Spirifer Verneuili, Murchison.
Receptaculites N&ptuni, Defrauce.

Besides these, as conspicuous fossils in the fauna, Kayser names —

Spirifer euryglosus, Schnur.
Sj,irifer nudus, Sowerby.
Rhynchonella pugnus, Mart.
Rhynchonella acuminata, Mart.
Produetus subaculeatus, Murch.
Athyris concentrica, v. Buch.
Atrypa reticularis, Lin.
Pentamerus galeatus, Dal in.
Orthis eijelensis, de Vera.
Orthis striatula, Schloth.
Melocrinus hieroglyphicus, ( roldf.
Phillvpsaatrcea verneuili, Edw. <V II.
Acervul'irin pentagona, Edw. & II.

This precise horizon, with the general sequence from the middle Devonian
Limestone to the upper or Condrozien sandstone, was traced by Kayser from
Belgium through these western German sections to the Harz sections, and
Poland, Russia, Petschora land, the Urals, Persia, and China.

I n each well-exhibited Bection there is

I. The rich middle Devonian fauna : brachiopods, corals, gasteropods,
laraellibranchs in abundant variety; trilobites, crinoids, and cephalopods
in lesser aumbi

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THE FOUR PRINCIPAL FAUNAS. 487

(2.) The Cuboides fauna, with a few species of brachiopods frequent ;
other brachiopods rare but occasionally present, and only rarely other
classes of organisms.

(3.) The Goniatite fauna, which is made up mainly of a few species of
Goniatites, and when distinct, very little else, but frequently blending with
the Cardiola retrostriata fauna, which is a sparse fauna with a few small
Goniatites, a few small lamellibranchs, and occasionally Tentaculites and
kindred forms.

(4.) Following this is the upper Devonian fauna of brachiopods and
lamellibranchs, the latter often large and of species distinct from those in
the middle Devonian.

With this order of faunas are associated the changes in sedimentation.
The first is a calcareous zone formed in an ocean basin not greatly disturbed
by shore mud. The second is a deposit of limestone mingled with much
clay, showing the waters to have been muddy and impure. The third is a
shale, occasionally calcareous, with nodules of limestone, indicating a con-
siderable amount of sediment of attrition, but its fineness of division suggest-
ing considerable distance from its source. The oscillations in the sedimen-
tation of the Devonian system in various places in Europe and America are
represented graphically in plate 11.*

We have here evidence of likeness in the general course of sedimentation
for all the central part of northern Europe, through the middle and upper
part of what is called the Devonian system. For the northwestern part of
the Continent and the southwestern part of England, in south Wales and
Cornwall, there is evidence of volcanic disturbances in the middle Devonian.
The volcanic disturbances, the stage of oscillations in the relation of the land
to the level of the sea indicated by the sedimentation, aud the fossil contents
indicative of the stage of biological progress, all agree in indicating uni-
formity in the geologic history of this whole region during the period under
consideration. It is difficult to conceive any explanation of the facts that
does not recognize a comparative contemporaneity for each of the several
stages, 1, 2, 3, 4, above named in all its European extent.

When we pass outside of this north European basin, differences in sedi-
mentation are found. In north Devonshire very little limestone appears,

* Explanation of Plate 11.

Each diagram is drawn to a uniform scale. The different rulings indicate different kinds of sed-
imentation : The right oblique ruling in the vertical columns at the right indicates limestone; the
right and left oblique ruling in the middle columns indicates shale or argillaceous deposits; and
the right and left oblique ruling with dots in the columns at the left indicates sandstone. The
horizontal divisions express geologic divisions of the Devonian system; the lower, middle, and
upper divisions standing respectively for the lower, middle, and upper Devonian.

The heavv curved line is drawn to represent the character of the deposits laid down at each stage
of the Devonian in the particular area represented by each diagram. For Instance, figure I repre-
sents the sedimentation of north Devonshire: at the bottom the sedimentation curve begins in the
sandstone, curves toward the finer deposits, and is in the shales before the close of the lower De-
vonian ; in the middle Devonian it is in the shales with an oscillation into the limestone, and then
backward it is formed in the sandy shales during the upper Devonian. In the Erbray section,
figure 5, the curve begins in sandstone but rapidly runs over to the limestone. The main part of
the lower and all the middle Devonian are limestones.

188 II. S. WILLIAMS — THE CUBOIDES ZONE AND ITS FAUNA.

from the lowest to the highest representatives of the Devonian. Arenaceous
Bhales, schists, slates, and sandstones, with some thin and more or less len-
ticular limestones, occupy tin- whole interval. There is, however, a progres-
sive change in the Faunas, which is fairly well distinguishable as coordinate
with the successive stages in the faunas of the Eifelian Devonian. In France
and Spain evidence of the Bame order of sequence is seen, but the boundaries
and divisions are less sharply marked. In Russia similar combinations of
species are recognized, bul the oscillations expressed by sedimentation are at
different stages as gauged by the biologic history. Still, in general, the
sequenceof faunas is the same. The mosl that can he said for the represen-
tatives of the system further east, in Persia and China, is that the associations
of species are closely like those of the several stages of the Devonian in
northern Europe.

The Frasxien Fauna of Gosselet.

Gosselet describes the " Calcaire et Schistes de Frasne " in Belgium, giv-
ing lists of fossils, in the " Es<piisse ( leologiipie," Lille, 1<S.S0, pp. !)5-97.
The species enumerated by him are —

Bronteus flafo I lifer. Rhynchonella cnboides.

Orypha us arachnoides. Camarophoria formosa.
Goniatites inlumeseens. " megistana.

Spirifer nudus. Pentamerm brevirostris.

" urii. Orthix striatula.

" euryglosus. Produdus subaeuleabus.

" bifid us. OyatHophyllum hexagonum.

" vemeuili. Favosites cervicornis.

" orbeUianus. Alveolites osquaUs.

Spirigera concentrica. Ac milnrin goldfusn.

Atrypa reticularis. Receptaculites neptunu
Rhynchonella simila vis.

jselel notes as a Btriking fact connected with these Frasnien shales and
Limestones the inconstancy and irregularity of the calcareous part. Some-
times the limestone is at the base ; sometimes in the middle or in the upper
part. Cn one of the sections near Prasne the limestone forms a compact mass
500 to 600 metres thick, in regular beds. Easf and wesl it is represented by
-hales throughout.

All through the northern part of Europe, also in Russia and the CJral
mountains, this Ouboides fauna i- associated with the shaly limestones ami
calcareous Bhales terminating the Devonian series of limestones, running up
into sandy Bhales, these latter often black ami bituminous, a- at Budesheira
and in the Dominick Bchists of Petschora land.

HUXLEY ON HOMOTAXY. 489

In America the same, conditions of sedimentation mark the place of the
particular fauna which we correlate with it.

The Tully limestone is always impure, argillaceous, and not only varies
in thickness, but changes at its extremes into calcareous shales, and is fol-
lowed above by a fine, black bituminous shale.

HOMOTAXY AND CONTEMPORANEITY.

For all the region so far considered, the evidence is all in favor of the
view that in a general way and within comparatively narrow limits the
groupings of species into like faunas for the Middle and Upper Devonian
period were contemporaneous and not merely horaotaxial.

In 1862 Professor Huxley, in the Annual Address of the President of the
Geological Society, advanced the view that the correlation of the geologic
formations of separate regions by likeness of fossil contents was correlation
of order of sequence (homotaxy) and did not imply contemporaneity.
He said : " For anything that geology or paleontology is able to show to
the contrary, a Devonian fauna or flora in the British Islands may have
been contemporaneous with Silurian life in North America or with a Car-
boniferous fauna and flora in Africa" (Q. J. G. S., Vol. XVIII, p. xlvi.).

Although this is probably nearer the truth than the views then generally
held as to uniformity of geologic events for the world, the very methods of
research which Professor Huxley has done so much to promote enable us
now to predicate much more closely the actual temporal relationship of two
separate faunas.

When we consider the area of northern Europe alone, including south
Devonshire, and extending eastward to Russia and the Urals and possibly
to China, the facts all point to a contemporaneity of the Caboides zone for
the whole region.

Assuming this fauna to mark a definite point in the geologic series of
Europe, the place of its occurrence in the stratigraphic series may be called
the Cuboides horizon or zone, and the place the fauna occupies in the history
of marine faunas, of which it is one, the Caboides stage.

We next raise the question, Is there any evidence of contemporaneity be-
tween it and the zone holding the homotaxial fauna in America? The Tully
limestone of New York, from both stratigraphic and paleontologic points of
view, is homotaxial with the Caboides Schichten of Kayser.

The Tully Limestone and its Fauna.

The Tully limestone is a zone of argillaceous limestone, ranging from a
few feet to over fifty feet in thickness, the outcrop of which crosses the
middle counties of New York state from Ontario to Chenango counties, but

LXV— Bum.. Gbol. Soc. Am., Vol 1, 1889.

190 II. S. WILLIAMS — Till-: CUBOIDES ZONE AND IT- FAUNA.

i- doI clearly recognized in the sections .smith of New York. In New York
the outcrop is losl to the eastward and to the westward, nol bo much by
thinning <>nt as by a decrease, until unrecognizable, of the calcareous ele-
ments, ami a failure of the peculiar species. In the central pari of its out-
crop this Limestone appears at the top of the Hamilton formation, which
consists of a series several hundred feel thick of soft shahs, with a few more
or Less calcareous zones; and it is followed immediately by a black shale
which gradually loses itself by alternate oscillations in a gray, more or Less
arenaceous shale and argillaceous sandstone, known in New York as the
Genesee shale and the Ithaca group, ami the more sandy portion above as
the Portage group. In the region where the Tully Limestone is will devel-
oped the black shales contain a fauna corresponding to that <d' the Cardiola
retrostriata zone of Europe, ami there is in the sandy Bhales above a fauna
rich in < }oniatiU .-• where hest developed.

At ilm western extreme of the 'Fully lime-tone outcrop in < mtario county
lias been seen, far up in the Portage formation, at High Point, a calcareo-
silicious /one of about six feet in thickness, containing a rich Brachiopod
fauna, which is "particularly interesting, as 1 have 'previously shown Am.
Jour. Sc. III. Vol. XXV, p. 97, 1883), on account of its relation to a De-
vonian fauna in Iowa, and to faunas, as we shall see Later, in Europe als >.
The Ithaca zone also contains some of the species of the Cuboides zone, as
we shall see later.

Above all these comes the typical Chemung fauna of American writers,
which i- comparable with Gosselet's Famenien and Condrozien of North
Prance ami Belgium.

For this Btudy the mure importani species in the Tully limestone of New
York are the brachiopods. They art —

Orihia tullierms, Vanuxem.

Streptorhynchu8 Chemungensis, var. arctostriata, Hall.
Strophodonta perplana (var. tulliensis, II. 8. W\), Conrad.
Chonetes (Jogani, var.) <nir<>r<i. Hall.
Alri/jHi r< Uni/iiris, Linn..
Atrypa aspt m, Schlotheim.
Rhynchonella venustula, Sail.

Spirifer mucrojvxtus 'var. tullien . II . S. W. ■, Conrad.
Cyrtina hamiltonensis, Hall.
Spirifi r tulliue, I [all.
Amboccdia umbonata, Conrad.

Productella epinulioosta (var. tulliemis, II. B. W. . Hall.
Spirifi r fimbriaius, Conrad.
Beside these art- species belonging to other orders, a- follows:

PhaCOpS bufo, ( ' ret ii.

Dalmaniti i ealliteli -, or l»><>thi, < Sreen.

FOSSILS OF THE TULLY LIMESTONE. 491

Bronteus tullius Hall.

Platyceras symmetricum, Hall (var.).

Also representatives of the following genera:

Amplexus,
Aulopora,

Euomphalus (rare),
Pleurotomaria,
Loxonema (rare),
Conocardium (rare),
Schizodus (rare),
Orthoceras,

Goniatites (rare), aud
Tentaeulites.

Some other genera are represented, but the complete list of genera and
species, with descriptions and comparisons, is reserved for a future paper.

What do these Tully forms testify as to their relation to the Cuboides
fauna of Europe ?

The trilobites of the first two genera (named above) are Hamilton species,
traces of which are found still higher in the Chemung. The Bronteus ap-
pears to be unique and is closely allied to a form of the European Cuboides
zone (B. flabellifer Goldfi).

Of the genera of gasteropods, corals, lamellibranchs, and cephalopods,
I will only say here that the species are either identical with or closely
allied to those of the Hamilton formation below, and the differences at
present recognized, on comparing them with their representatives in the
preceding zone, are not so great as the differences between the latter and
their European representatives of the middle Devonian.

Again, of the brachiopods. the Atrypas, are indistinguishable from forms
occurring both below and above ; hence they are valueless in defining the
zone. The Oyrtina, the Ambocwlia, the Streptorhynclms, and the Spirifer
fimbriatus are seen below and above this zone,, and are also represented by
closely allied forms in Europe.

The Chonetes aurora (figures 10, 11, plate 12) is characteristic of the zone
in New York, but the species is not known outside the state. It appears
to me clearly distinct from the Burlington Chonetes lor/ant, Norwood and
Pratten; hence it is of no value in correlating with the Cuboides zone.

Spirifer mucronatus var. tulliensis is a well-defined variety, strictly inter-
mediate between S. mucronatus, which precedes it, aud S. mesoeostalis, which
follows it, in the central part of the region under discussion. It is as perfect
an example of a connecting link as one could wish. The Spirifer tullius is
a forerunner of S. mesostrialis of the following Ithaca fauna, and while it

192 II. S. WILLIAMS — THE CUBOIDES ZONE AM' [TS FAUNA.

forms a characteristic Tully species in the local sections, it is valueless for
purposes of correlation (see figures L2, L3, plate 1- .

The Productella, varietally considered, appears to be distinctive of the
fully, lmi it also appears to be 1< »«-;il and belongs to a race which is quite
sensitive to local conditions all through the Devonian and Carboniferous.

Comparison of New York Species with European Forms.

In the study of all these fossils, oo facte have thus far appeared which enable
u- to affirm other than that the fauna is the regular successor of the preced-
ing Hamilton fauna of the same region. Compared with species of foreign
I Devonian faunas, these species show less close affinities with them than with
their representatives in the Hamilton formation below. At the same time
they are nearer to the species of the middle Devonian of foreign sections
than to those of any other zone in those sections. Tiny indicate general
homotaxial relationship with the faunas of the upper part of the middle
Devonian of Europe.

We are now restricted to three species:

Orthia bulliengis,

Strophodonta perplana var. tullierms, and

Rhynchont lla venustula.

Orthis tulliensis (figure 16, plate 12 is of a race not represented in the
Hamilton of New York. In 0. propinquaof the Corn iferous we recognize its
forerunner, and can trace its ancestral line well hack into the Silurian. In
Iowa, however, this, or a closely allied form, 0 iowensis, is associated with a
Hamilton fauna; and in the European Devonian there is a representative of
the same race, 0. striatula, ranging with slight mutations throughout the
Devonian system and over the whole region of Europe and A-ia. A later
mutation of the same race is seen in the common Carboniferious form, Orlhis

upinata. For the Devonian the differences recoguized between the O.
tullieiuria and the 0. impressa of the following Ithaca zone are no greater
than the differences between either one and its representatives in Europe or
in Iowa.

Since the race did not appear in the I [amilton of New York, we conclude
that 0. tullienris came into the region by migration and not by direct
descent from any Hamilton form of the same region. Its appearance in the
following zone in New York i. e., the tthaca formation, and in the High
Point fauna in Ontario county — suggests thai the fauna to which it belongs

i- more directly associated with what follows than with the N.-w York

I [amilton buna.

Aiiuiher point is furnished by the Btudy of this Bpecies: 0. tulliensis, in
respect of the variable characters of its race, presents a much greater degi

AFFINITIES OF ORTHIS AND STROFHODONTA. 493

of constancy than do the forms from Iowa, called 0. ioivensis, or the forms
of 0. impressa from the Ithaca zone.

In the European localities, also, considerable plasticity is seen, especially
where the race is abundant. This is interpreted as indicating that the
Tully species is a recent arrival in the local fauna.

The second species, Strophodonta perplana var. Tulliensis (figures 1-4, plate
12), is a mutation of the race which began in Stro])homena altemata in the
Trenton stage. In the Hamilton rocks immediately below the Tully, the
form is Strophodonta perplana ; in the Ithaca zone above, it is Strophodonta
mucronata, Conrad. This is followed by Strophodonta perplana var. nervosa^
Hall, of the higher Ithaca and Chemung zones.

Without going into details, the prominent points in the geologic mutations
are that the race beginning in the Trenton, Strophomena altemata, runs through
a number of species differing in the proportions of form but retaining the
structural features and surface markings with considerable constancy. At
the base of the Devonian, two races diverge from the stem ; other features
remaining alike, the one is a thin, flat, and but slightly curving form, the
typical Strophodonta perplana, Conrad. This appears to be an American
type and is seen with variations all through our Devonian, but it is not
described in the European Devonian. The other, beginning flat, in the
course of its growth more or less suddenly bends toward the dorsal valve.
This is the Orthis inter strialis, Phillips, of the European Devonian, and
Strophomena incequistriata, Conrad, of the New York Hamilton. The inter-
strialis race is recognized in our Chemung Strophodonta cayuta and in the
upper and middle Devonian of Europe and the east in Strophomena dutertril
and S. aselli.

In the European race, as we reach the Cuboides zone, the terminations of
the hinge develop into slender, mucronate points. In the American race
these mucronate points first appear in the Tully limestone forms (figure 1,
plate 12), and are characteristic of the race afterward till it ceases.

The representatives of this type of Strophomena are common in Europe
throughout the Devonian, going under the specific names interstrialis, aselli,
and dutertril, and the conspicuous development of the mucronate points did
not appear till about the stage of the appearance of Rhynehonella cuboides.
The valuable testimony for correlation furnished by the Tully Strophomena
is that although plainly, in its main features, an American race of its genus
up to the Tully limestone stage, from there upwards it shows affinity with
the European representative as it appears in Europe in the Cuboides zone

and upward.

The third species, Rhynehonella venustula, Hall (figures 4, 8, 14, 28, 24,
27, 21), 31-34, plate 13), is by common consent closely allied to R. cuboides
of Europe, the chief distinction lying in the number of plications in the

194 II. s. WILLIAMS — THE CI BOIDES ZONE AND [TS FAUNA.

median fold and sinus which arc less than in the prevailing type of the
European euboides (plate 13). Throughout the Devonian of Europe and
Asia this species is found associated with a particular fauna at the base of the
upper Devonian, and its presence is regarded as indicative of a common

•logic horizon; and since it can be traced regularly from country to
country, the terranes holding this fauna for the eastern continent may lie
regarded as approximately contemporaneous.

There is a mutation of the sa species, called procuboides (figure L3,

plate 13) by Kayser, occurring a little lower in some of the sections, the
distinctive features of which are seen to be characteristic of immature forms
of the true Rhynchonella euboides.

Among the European forms there is considerable variation in the number
of plications on the median sinus; some specimens of the American type,
however, have as many plications as some of those of the European forms
not possessing the maximum number for that type. It is observed, further,
that these plications increase in number with the growth of the individual.

This Rhynchonella venustula shows a closer affinity to the early mutation
of the European form in the characters common to both, but in its own
peculiar characters it shows a stage of development akin rather to the typical
euboides of Europe. To explain this fact we are led to believe that the two
forms had a common origin up to near the beginning of the Ouboides -tage,
but at that stage were separate and developed their local characteristics.

All three species thus agree in bearing intrinsic evidence of a relationship
between the faunas of the New York and European Devonian, more intimate
during the stages from the Ouboides zone upward than for those previous to
that zutie.

Comparison of European Species with American Forms.

There are beside these a number of species belonging to the Ouboides

fauna which do nol appear in the Tully limestone. Kayser has given a

list of species typical of the Ouboides zone of Ais la Chapel le and the Eifel sec-
tion at Budesheim(p. 185). Gosselet has given lists for the Fraxnien (p. lSv
There are li<t- given for the Merger Kalk, the Devonian limestone of
.--.lit 1 ■ Devonshire, and the various sections of Russia and the I Irals, l>v other
authors. In the Btudy of these lists the brachiopods also besl Berve our
purposes on accouul of the much fuller details we possess of their specific and
varietal character- and of their distribution. Among the species of these
lists the following are quite generally present in the Ouboides zone.

Of Spirifers there are generally] recognized as belonging to the fauna
Spirifer nudus and S. euryglosus or pachyrynchiu. In the American Devon-
ian the tii-t representative of this race of Spirifer occurs above the Tully

INTERCONTINENTAL RELATIONS OF FAUNAS. 495

limestone, at the base of the Ithaca group. It is Spirifer Icevis of Hall,
which closely resembles Schnur's S. euryglosus ; the other names are syno-
nyms or closely related species.

Amboccelia umbonata, Hall, may be said fairly to represent S. urii, Flem-
ing, of the Cuboides zone. This race with slight variation ranges throughout
the Devonian, both in America and Europe, and well into the Carboniferous,
and occurs in the Tully fauna as Amboccelia umbonata.

S. bifidus, Roemer, is not represented in the American Devonian. It
presents some modifications seen in the later types of our S. mesocostalis,
but it belongs to a different race.

It may be noted here that the bifurcation of the plications of Spirifer and
the appearance of plications in the sinus are features continuing from the
base of the Devonian to the Carboniferous in Europe. In New York there
is a gap from S. arenosus of the Oriskany to the S. disjunctus of the De-
vonian, in which no representatives of the race appear. In Iowa 8. ivhit-
neyi and S. hungerfordi in a measure fill in the gap.

Spirifer disjunctus, verneuili, orbelianus, archiaci are names applied to
varieties of a common race which appears in the Cuboides zone of Europe,
and also below in the middle Devonian. In the New York sections it first
appears in the Ithaca and High Point (Naples) faunas, both of them above
the Tully limestone; and again later, as S. disjunctus, the most character-
istic form of the Chemung fauna. In Iowa S. whitueyi occurs associated
with middle Devonian species, as in Europe.

Athyris concentrica is generally present in the Cuboides zone of Europe,
but is apparently wanting in the faunas in America most closely allied.
There are representatives of the genus both below and above, but I have not
found it in the fauna under consideration.

Pentamerus galeatus, or brevirostris, or some other species, is occasionally
reported for the Cuboides fauna in Europe. With us the species is possibly
represented by rare examples, but it is a rare form even in the middle
Devonian.

Productus subaculeatus, Murchison, is represented by the Productella spe-
ciosa, Hall, abundant a little higher than the Tully.

Productus dissimilis, Hall (hallianus, Walcott), shown in figures 8, 9, plate
12, is seen in the more eastern sections of Europe. The representatives of
this genus akin to the European forms occur after the Tully and not before it

The Camarophoria formosa, Schnur, is either a distinct species or is rep-
resented by our Leiorhynchus mesacostalis of the Ithaca zone.

Orthis striatula, Schloth., and Orthis eifeliensis, de Vera., are represented
by our Orthis txdliensis and followed by Orthis impressa; but in New York
have no Hamilton forerunners.

Rhynchonella pugnus and R. acuminata are frequently reported in middle
Devonian faunas of Europe, and in some sections are in the Cuboides fauna.

496 II. S. WILLIAMS — THE CUBOIDES ZONE AND ITS FAUNA.

They arc particularly characteristic of higher zone?, and are abundant in
various Carboniferous limestones. With us they begin in New York after
the Tullv, in the Ithaca and Sigh Point zones (figures 5-7, plate 12) ; in
Iowa they appear in association with middle Devonian fauna-, and higher
up in the Carboniferous of the western part of the < tinent.

The form which Kayser described as Rhynchonella procuboides (figure 1-'!,
plate 13) appeared below the true Cuboides zone in the middle Devonian
limestones. It is evidently the forerunner of Rhynchonella cuboides, and its
occurrence below is quite in consonance with the other facts, showing that
the fauna was indigenous to Europe, but thai all the representatives of the
fauna in New York sections first appeared with or above the Tullv limestone.

The Bronteu8 flabelUfer, which occasionally appears in the European zone,
may be regarded as represented by Brontevs tullim, Hall.

0ryplweu8 arachnoides, reported by Gosselet, is represented in our closely
allied form Dalmanites boothi, Green, but this as well as the Phacopa rona
are the apparent successors of the indigenous Hamilton species, and this is
near their latest, rather than their first, appearance.

The corals and Rcci'ptuciiHtts nepluni, which are common in the lower
/one of the Belgian and Eifel sections, are more local in their character, hut
most of the corals are generally represented below and not often above.

Thus it will he seen that the European fauna of the ( 'uboides zone is
represented almost completely hy the fauna which in New York begins with
the Tullv limestone. .Most of the specie- regarded a< characteristic <>f this
zone in Europe there appear also in lower zones, or are represented by closely
allied forms that may he safely regarded as their ancestors.

These same species are conspicuous in the New York series by beginning
with the Tullv limestone and appearing frequently above, but showing no
closely allied species in the preceding middle Devonian.

The Transition between the Hamilton am> the Ti i.i.v Faunas.

I have examined a large amount of material from genuine Tullv limc-
stone, and also considerable more doubtfully referred to thai horizon. In
most places the Hamilton rock- are richly fossiliferous immediately under

the Tullv limestone. These former, though mainly shales. itain limestone

beds which in hand specimens are rarely distinguishable from thegenuiue
Tully above; bul the characteristic species of the Tullv arc warning, and
characteristic Hamilton Bpecies are abundant in them. Much confusion has
thus arisen, and the Tullv fauna, as reported in lists,* is very imperfect by

; o. Williams in the R< porl ol the 8i oglsl of New JTork (Sixth

Annual Report of the - t, Albany, 1887. p. 26) \ considerable number of the si les re-

. .1 in iiii- ii-i l ha i oed in Oi Election made by the author of the li~t and And them

containing them Indistinguishable from -i linens "Mni I al the same locality be-

i uiiv limestone In limestone layers filled with llamiii"ii sp' ■ ]•■•-. bul never in the Tally
limestone Itself.

CHRONOLOGIC RELATIONS OF THE TULLY FAUNA.

497

the inclusion of many Hamilton species which do not belong in the lime-
stone.

There are about fifty genuine Tully limestone species. Of these less than
twenty-five are at all commou, and the other twenty-five are Hamilton species
which do not appear above the Tully, or are unique forms of Hamilton types.
Of the more or less common Tully forms fully one-half are also clearly
Hamilton species or their descendants, or are unique forms.

The change in fauna which begins with the Tully limestone and makes
the characteristic upper Devonian fauna includes the appearance in New
York of at least ten or a dozen species which have closer affiuities with
species of the middle Devonian in Europe than with any previous species in
the New York series.

The following table will illustrate this point :

European Species.

—

; _

New York Species.

Rhynchont I la cubo ides

—

Rhynchonella venustula.

Spirifer archiaei . ")
" verneuili _ \
" disjunctus J

—

Spirifer disjunctus.

Spirifer euryglossus or
nudus.

—

Spirifer Icevis.

Rhynchonella pugnus

—

Rhynchonella pugnus.

Rhynchonella acuminata

—

Rhynchonella acuminata.

Productus subaculeatus __ j
Strophodonta productoides j

—

j Productus sjieciosa var.
{ spinulicosta.

Atrypa reticularis . )

" aspera _. . j

—

Atrypa reticularis and var.

Orthis striatula

—

X
X

—

X
X

—

Orthis tulliensis and var.

Spirifer urii _ .

Ambocadia umbonata or

Spirifer subumbonus.

Phacops latifrons .

Phacops bufo.
Dahnanites calliteles.

Cryphceus arachnoides -- -

—

Bronteus fiabelifer .

—

Bronteus tullius.

PlatyceraS) sp. _

—

Platyceras, sp.

Of the ten most characteristic species of the Cuboides zone of Europe,
marked C iQ the above table, all are represented by closely allied forms in
the underlying middle Devonian of Europe ( — C)-

LXVI— Bull. Geol. Soc. Am., Vol. 1, 1889.

I'.IN li. S. WILLIAMS — THE CUBOIDES ZONE AND ITS FAUNA.

Of their New York representatives, six are not known in the underlying
middle Devonian ( — T.)j &nd of the other tour, two are Bpecies common
below and above in both hemispheres, and the other two are more common
below in New York as well as in Europe.

Review of the Argument.

To review the arguments : the study of these faunas brings out the fol-
lowing facts. The fauna of the Tully limestone is made up of two groups
ofspecies; first, those having closely allied forms in the immediately preced-
ing middle Devonian formations; second, those having closer affinity with
European forms than with any species occurring in lower formations in
America. The first group may he regarded as representatives of indigenous
races and as direct descendants of the lower forms of the same region. The
second group must he regarded as immigrants from some other region.

In the Tully limestone the latter class arc few, and they are species repre-
sented by very closely allied forms in the Cuboides zone of Europe, which
there were represented by preceding forms which were clearly their ancestors.

In the Cuboides zone of Europe are a considerable number of species be-
side the few seen in the Tully zone. They all have unmistakable forerun-
ners in the formations preceding the Cuboid's zone in Europe and may be
considered as indigenous there. In America all of them follow the Tully
limestone zone, generally in the next or in some succeeding brachiopod
fauna, or else are first present in the Tully limestoue itself.

This series of facts is explained by the hypothesis that during the early
stages of the Devonian period there was little or no communication between
the basin in which the American species were living and the European
basin, but thai near the opening of what is called in Europe the Ouboides
stage, communication was formed, and European Bpecies migrated and be-
came mingled with the eastern American forms; that the time of the ar-
rival here of the migrants was while the Tully lime-tone was being depos-
ited ; that the time when the migration left Europe WHS mar the time of

deposition of the base of the ( iuboides /one ; that the correlation thus estab-
lished is one doI merely of hoinotaw, but within relatively BnOrl limits, of
contemporaneity ; and that the 'fully limestone may be said to have been
deposited during the period of deposition of the Ouboides Schichten of Eng-
land, Belgium, Pranci . Germany, Russia, ami the East.

( \>N< II SION.

'fhe conclusion we draw from this study of the faunas of the Ouboides
zone and the Tully limestone is that within vn narrow limits, geologically

TULLY LIMESTONE AND CUBOIDES SCHICHTEN CONTEMPORANEOUS. 499

speaking, the point in the European time scale represented by the beginning
of deposition of the Cuboides Schichten of Aix la Chapelle and Budesheim is
represented in the New York sections by the Tully limestone ; and, second,
that the representative of the fauna of the Cuboides zone of Europe is seen
in New York not only in the Tully limestone but in the shaly strata for
several hundred feet above, including the High Point zone in Ontario county
and the Ithaca group in several counties further east.

Therefore, if we wish to express precise correlation in our classification
of American rocks, the line between middle and upper Devonian formations
should be drawn at the base of the Tully limestone, to correspond with the
usage of French, Belgian, German, aud Russian geologists, who include the
Frasnien, Cuboides Schichten, and correlated zones in the upper Devonian.

DISCUSSION.

Mr. C. D. Walcott : Professor Williams' paper is of unusual interest, as
he has shown very clearly that the theory of Huxley that there is no homo-
taxial relation between the subdivision of the geologic systems on the Amer-
ican and European continents is not altogether correct. This study of the
Cuboides zone has shown one limited horizon, at least, that is widely dis-
tributed in Europe which is also readily recognized in the state of New York.

Expl w ltioh <ik Plates.
PLATE 12.

Pionai l—Strophodonta mueronata, Conrad, var. Tally limestone; Cuyler, N. Y. Ventral valve

natural -
I h.i ai - -'. 3, I— The same: enlargement of the surface markings, Bhofl ing the mode of bifurcation

and intercalation of the plications on specimens similar in other respects from a single

locality. Figure '1 is enlarged about three diameters, and figures :i and 4 about ten diameters.
Fiot bes 5, 6, IShynchoneUa pugnus, .Martin, var. called fi. aita. Calvin. Solon, Iowa. Natural size.
Piot ass 8,9— Productus hallianus, U'alcott (-- Productus dissimiUs, Hall). Ithaca formation, Ithaca,

N. V. Ventral (8) ami dorsal (9) valves, natural size.
Fioubi 10— Chonetei logani, var. aurora, Hall. Tally limestone. Ordinary size and form.
Fi'.i BE 11— The same. Enlarged nearly four diamet-rs.
Fionas 12— Spirifer mueronatus, Hall, var. tullu nsis, II. S. W. Tully limestone. Tinker's Palls, N. Y-

Exfoliated specimen of dorsal valve representing the common form of the Tully variety.
PlOl iik IZ— Spirifer mueronatus, Hall, var. Hamilton formation. Chenango, N. Y. This Bpedmen

represents one of the later Hamilton mutations of the species, and figure 12 represents the

stage of mutation intermediate between figure 13 aud Spirifer nusacostalis of the Ithaca

fauna.
Fioi Bis U. 16 Platyceras tymmetricum, Hall, var. Tully limestone; Truxton, N. Y.
FlOUBI 16— Orthis tuUiensis, Vanuxem. Tully limestone; Tinker's Falls, N. Y. Exterior view of

dorsal valve of specimen larger than average size.

PLATE 13.

Copit iiin! tiqiires of Khynchonella cuboides, Sow., etc., an ■ of specimens of R. venns-

tula, Hull, / d, the geographical modifications of the form first notit the

name Atrypa cuboides, Sow. (I8ln). From England, Germany, Russia, China, and .V km.

Fiocbes 1, 5— Atrypa cuboides, Sowerby ; South Devonshire. Trans. Geol. Soc, 2d Ser., Vol. V, PI.

I.VI, Bg. 24.
K i • . i i.)- '//>'! itnpleta, Sowerby; South Devonshire. Trans. Geol. Soc, 2d Ser., Vol. \', IM-

I.VI I, fig
Piovku 1, 19— Bhynehonella procuboides, Kayser; Eifel. Zeitschr. d deutseh. geol. gesell., Bd.

Will, Taf. IX, tigs. 3a, 36.
].-,,,, ,.,. g_ Terebratula Sowerby), Phillips; South Devonshire. Figs, and Descr. Paloaozoic

Mils, etc, PI. XXXIV. Bg. 160.
i-'i-.i i.i - 3, 0, 16, 30— Terebratula < - rerby), Geinits; Saxony. Die Versteinerungen der

Grauwacken-formatlon, Beft LI, Taf. 14, figs. 28, 20.

l- ;i- i,-, 14,23,24,27,20,31,32, 33, 84— EhynchoneUa venustula, Sail; Tully limesl , Tinker's

La, etc., New fork. Original drawings.
Fiqubh 10, 11, 12, 16, 17, 18, 10, 21, 22, 26, 28— Rhynchom . Sowerby; according to sundry

authors, u^ follows :

Fioubh 10, 21— Koltaban, 1 Russia; Techernyschew. Mem. du ComiU geologlque, Vol. 1, No. 8,

FioubbsU, 16 Dewltsa, | Taf. Ill, figs. 10a, 106, 11a, 116.

Fi..i bi - 18,2! /.•■rin. Russia; Tsohernysohew. Mem. du Com i to U'oiogique, Vol. Ill, No. '■'■, Taf,

XIV, tigs. \e, id.

Fioubbs 12, 17— Woronesch, Russia; WenjukofT. Die Fauna der Devonischen systems Im Nord*

tlichen I Centrales Russian I, 1888, Taf. V, figs. lOo, 106.

Fiodbbs 19, 26— Ohlna, Kayser. Von Rlchthofens' China, Vol. IV. Taf. VIII, tigs. 2s, 2<i.

>— Grand, Germany, original drawing.

BULL. GEOL SOC AM.

VOL. 1, 1389, PL

BULL GEOL SOC. AM.

VOL. 1, 1S89, PL 13.

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA

Vol. 1, pp. 501-516

THE CALCTFEROUS FORMATION IN THE CHAMPLAIN

VALLEY

EZRA BRAINARD and HENRY M. SEELEY

WITH A SUPPLEMENT ON

THE FORT CASSIN ROCKS AND THEIR FAUNA

R. P. WHITFIELD

WASHINGTON

PUBLISHED BY THE SOCIETY

April, 1890

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA
Vol. 1, pp. 501-516. April 29, 1890

THE CALCIFEROL!* FORMATION IN THE CHAMPLAIN

VALLEY.

BY EZRA BRAINARD AND HENRY M. SEELY.
[Read before the Society December 27, 1889.)

CONTENTS.

Page.

Introduction 501

The Formation in General 502

Definition 502

Thickness, Variety, and Faunal "Wealth 502

Principal Divisions 503

Sections 505

East Shoreham Section 506

Shoreham Center Section 506

Orwell Section 506

Fort Ticonderoga Section 506

Southeast Charlotte Section 507

Providence Island Section ._ 507

The Fort Cassin Strata 507

The Canadian Exposures 508

Misapprehensions Corrected 508

Recapitulation and Suggestions 509

Discussion 512

The Fort Cassin Rocks and their Fauna: Bv R. P. Whitfield 514

Introduction.

The region which we have under investigation, lying between the Green
mountains on the east and the Archeau heights on the west, and extending
from Benson, Vermont, and Ticonderoga, New York, on the south, to Phil-
lipsburgh, Canada, on the north, has a breadth of about twenty miles and a
length of not far from eighty.

Near the western side of this geological cradle lies Lake Champlain, with
its islands. On the Vermont side, east of the lake, all the rocks of the Lower
Silurian series appear — Potsdam, Calciferous, Chazy, Black River, Trenton,
and Utica slate. These rocks sometimes lie in their natural order, fQrming

LXVII— Bum,. Geol. Soc. Am., Vol. 1. 1880. (r>01)

502 BRAINARD AND SEELY — THE < HiCIFEROUS FORMATION.

great monoclinals where the Archean mass to the west of them has been bod-
ily raised, leaving these dipping principally to the east. ( tften, however, they
appear as though an immense earth wave coming from the east had broken
itself along the crest into great fragments, which, displaced and crunched
together, are lying in confusion, while another portion of the wave-mass has
been shoved up and over, bo that the younger rock may be adjacent to or
below the older. Near the flank of the Green mountains the disturbances
ami metamorphism have heeu so great that the sequence of the rocks is made
out with greal difficulty.

Our work ha> Keen conducted chiefly on the islands and along the eastern
border of the lake, and the results of our investigations, so far as they per-
tain to the Calciferous formation, are here presented.

The Formation in General.

Definition. — The term Calciferous is a convenient one, and is used in the
sense in which it was applied by the early New York geologists — i. '., to
designate all the strata included between the Potsdam sandstone and the
( lhazy limestone.

Directly beneath the Calciferous, the Potsdam consists of magnesian lime-
stone and sandstone, the latter containing fragments of brachiopods related
to Lingvla. The overlying Chazy may he separated into three divisions,
which, numbering from below, may he designated as .1. B, and < '. The
first, .1. is characterized by the presence of abundant fossils; its Bponges,
corals, cystids, orthids, and gasteropods. B, the part of the Chazy best
known by authors, is characterized by M<i<-tnr><i magna, Strephochetus, and a
massive Stromatocerium. C has its dove-colored limestone with bands of
magnesian limestone, its many corals, and its Solenopora, Orthoceras, Caly-
mene, TUamus, and RhynchoneUa. Our work with the Chazy, which forma-
tion i- so largely developed in the Champlain valley, is now well advanced,
and we hope goon to he able to present the complete results of our study.

The line- between the Potsdam and Calciferous and between the Calcifer-
ous ami Chazy are, ;ii this time, only provisional; later investigations must

fix the exact boundaries. The lower line is drawn just ahove the foBSiliferoUB

Potsdam; the bottom of the Beries is a drab magnesian limestone, resting
upon a vitreous sandstone; the higher, at the bottom of a sandstone which
i- a— iimed to he the base of .1 of the Chazy a Bandstone recognized by the
Canadian survey,'1 which possibly corresponds with the St Peter sandstone
bo largely displayed in the central Btates of the west.

Thickness, \'uriih/, and Faunal Wealth. — In our study of the Calciferous
formation we have been surprised at its development, at it- vast thickness, at

li>K.v "f « uiado, 1863, p. i

THICKNESS AND FAUNAL WEALTH OF THE CALCIFEROUS. 503

its variety of rock, and at its abundant fauna. That the great masters of
geological science who made explorations on this ground — Professor Emmons
on the New York side of Lake Champlain, aud President Hitchcock on the
Vermont side — should have made such brief mention of this grand sub-
division must be attributed to the fact that they had wide areas to examine
and but brief time allotted them. The Calciferous is, moreover, a most dif-
ficult formation to decipher because of its great thickness, the absence of
fossils in most exposures, and the resemblance to each other of its various
beds of magnesian limestone.

The formation is essentially one of magnesian limestone, interstratified
with bauds and masses of pure limestone, pure silicious sandstone, and mix-
tures of these; or a calciferous sandstone, from which the name came.

Professor Emmons * gives the thickness as between 250 and 300 feet ; but
the upper part of his Calciferous has been transferred to the Chazy. Presi-
dent Hitchcock in the Vermont report f assigns it a thickness of 300 feet.
But section after section demonstrates a thickness of six times that amount —
that is, 1,800 feet. The Vermont report gives the number of fossils as four
or five, and in the subsequent pages mentions two more. A collection, not
as yet by any means complete, has afforded us over ahuudred forms. These
fossils can be best enumerated with the various horizons at which they
occur.

Principal Divisions. — The formation is not nnfrequently marked by abrupt
changes in strata ; and from lithological aud faunal characteristics, a basis
may be obtained which may be helpful for study. The divisions may be
named A, B, C, D, and E, reading from below upwards ; and in this natural
order they will be described.

Division A rests upon the uppermost member of the Potsdam. The rock
is a dark bluish-gray magnesian limestone, massive or sometimes in beds one
or two feet in thickness, more or less silicious, weathering dark, sometimes
with a tinge of yellow. Nodules of white quartz are abundant in some of
the higher layers, and near the top large masses of black scoriaceous chert
make their appearance.

Thus far division A has furnished no fossils. It has a thickness of 310
feet.

Division B is characterized by the presence of masses of nearly pure
reticulated limestone, weathering white, intermingled with light-colored
dolomite. The bedding is very obscure. Dolomite prevails in the lower
part, and again above the middle; the middle and upper portions being
nearly pure limestone. This pure limestone, like the Birdseye in flinty
compactness, breaks easily with a conchoidal fracture.

Geology of New York, 1st-', i>. 106.
t Geology of Vermont, Vol. I, 1861, p. 270.

504 BRAINARD ANI> SEELY — THE CALCIPEROUS FORMATION.

The pure rock just above the middle of the division carries the fossil
Orthoceras primogenium, Vanuxem. It also contains those remarkable hem-
ispherical, banded masses which have hern described as concretions, but

which are now known to he of organic origin. These masses res! upon a
layer of oolite. They were described by Dr. J. II. Steel*in 1825, with a
figure illustrating them. Mather, in his report on the first geological dis-
trict of New York, copied both text and illustration, ami in a foot-note
added: " Some of the round masses described as concretions analogous t"
oolites are organic and will he described in the paleontological report.
The form found in Shoreham, Vermont, is hemispherical, from six to twenty
indies in diameter, handed from the center outward like agate, and with a
tinge of purple color. Microscopic sections show the Bpongy structure of the
calciferoua Bponges, irregular canal- penetrating the granular mass. Thia
form may belong to the Cryptozoon of Hall; J it is, however, probably
different specifically from the Saratoga fossil, and from the earliest known
observer it may he appropriately named Cryptozoon steeli.

The rock in cliffs looks like a wall of white marble. Reticulations of
dolomite appear on the weathered surface. The thickness of division //is

295 feet.

Division 0 is sharply separated from B below by a peculiar fine-grained
sandstone containing some calcareous matter. The weathered portions
resemble fine-grained wood, ami some layers are pin-holed with worm
burrows, Scolithua minutus, according to Wing. Upon this sandstone lies
magnesian limestone in beds weathering drab, and this is followed by Band-
stone, sometimes almost like quartzite, but usually calciferoua or dolomitic.
Above this, and the highest of the division, is a magnesiau limestone frequently
cherty. The whole division is made up of alternations of sandstone ami
magnesian limestone.

A few obscure undescribed specie- of gasteropods ami cephalopoda are
found in division < ', in addition to the numerous worm burrows at the very
bottom. The thickness is 350 feet.

Division h may be briefly described aa to it- lithology. It has at its base
blue limestone in beda one or two feet thick, often with maguesian limestone
aa well aa Bandy limestone, the latter weathering to a ferruginous granular

mass. Drab and brown magnesian limest follows, which contains also,

toward the middle, several beds of tough saudstone. Then comes Bandy
limestone in thin beds, weathering on the edges in horizontal ridges one or
two inches apart, giving the escarpment b peculiar, handed appearance.
Blue limestonea appear above in thin beda separated from each other by very
thin, tough, slaty layers, winch protrude on the weathered edges in undulat-

'.in. Jour. Science, l-i Sei . Vol. I \, pp 16 19
■ "wn fork. 1842, pp n i

- V..i U Bl

FOSSILS FROM DIVISION I).

505

iug lines. On the weathered surface the limestone often appears to be a
conglomerate ; in other exposures these conglomerates are replaced by
measures of nearly pure limestone, separated from each other by beds of
magnesian limestone.

This division, D, is particularly fossiliferous, the larger number of fossils
in the formation being found here ; the purer beds of limestone from bottom
to top bearing them. The following 35 genera, gathered from various ex-
posures of the division, are represented by species varying in number from
one to ten :

Triplegia

Orthls

Holopea

Loj)hospira

Bellerophon

Maclurea

Piloceras

Asaphus

Cryptozodii

Leptama

Metoptoma

Trochonema

Murchisonia

S abilities

Orthoeeras

Lituites

Amphion

Calathium

Streptorhynchas

Triblidium

Pleurotomaria

Euomphalus

Calaurops

Cyrtoceras

Nautilus

Havpes

IAngula

Hemipronites

Clisospira

Rhaphlstoma

Ecculiomphalus

Ophileta

Gomphoceras

Bathyurus

Ribeiria

The total thickness of division D is 375 feet.

Division E has fine-grained magnesian limestone in beds one or two feet
in thickness, weathering drab, yellowish, or brown. Occasionally pure lime-
stone layers occur, which are fossiliferous. Rarely thin layers of slate appear,
which also are sometimes fossiliferous.

Here, as in D above, we have observed Murehisonia, Euomphalus, Ortho-
eeras, Lituites, and Bathyurus. To them are to be added two genera of
encrinites represented by columns aud plates, together with Strophomena,
Bucania, Primitia, and Stenopora — six genera not previously mentioned —
making in the whole forty-one geuera for the Calciferous.

Division E has a thickness of 470 feet.

For all the divisions of the formation we have a total of 1,800 feet.

Sections.

Exposures at the various points offer opportunity for making sections ex-
hibiting the character and thickness of the rocks of the formation. Of the
sections observed and measured, only one or two can be described somewhat
in detail ; the others, though in almost every instance presenting some in-
structive features, must for the present be passed with a few words.

506 BRAINARD AND SEELY — THE CALCIFEEOUS FORMATION.

East Shoreham Section. — It was from a typical section la East Shoreham
that the litholo Jlcal peculiarities previously described were taken; the fauna]
characteristics, however, are those observed at various localities.

This section represents one of those rare exposures in which not only the
strata of the Calciferous, but the whole Lower Silurian, from the Potsdam to
the (Jtica slate, can be seen in one continuous -'Ties. This locality was firsl
pointed out by II v. Augustus Wing, and was referred to by him as " the
Bascom ledge."* It isa greal tnonoclinal, two miles in width and three to
five miles in length, In which all the Lower Silurian strata arc seen, with at
least two hundred feet of Potsdam sandstone at the base. The strike is some-
what sinuous, and the dip varies from X. '•• to 38° E., hut there are no
abrupt changes except at the uorthern and western borders. Much of the
rock is covered with soil, but exposures on the hill-sides, along the water
courses, and in the escarpments of cliffs are sufficient to reveal the character
and thickness of all the members of the Calciferous formation.

Short ham < 'rni' r Section. — Another uplift in which all the strata of the ( 'al-
ciferous are to be seen occurs in a tract extending from Shoreham Center

northeast about two miles to NewelPs mills. It i >bts of an anticline with

the Potsdam on the axes, and with the superjacent Chazy and Black River
formations, bearing characteristic fossils, on the western side.

Orwell Section. -In the town oft )rwell, which lies directly south of Sim re-
ham, the upper members of the Calciferous are brought up in an anticline.
AJboul two miles northeast of the village, in the bed of a stream — the North
branch — the anticline is so much abraded that all the lowest strata of divis-
ion ( ' are seen.

Fort Ticonderoga Section. — In the uorthwesl corner of the town of Orwell,
live miles southwest of shoreham village, is a hill known as Mount indepen-
dence. It rises nearly 200 feet above Lake Champlain and is about a mile
in length, the top along the north half being a Bmooth plain sloping gently
northward. This plateau ua- the old parade ground of the soldiers of Fort
Ticonderoga, which stood across the lake only half a mile to the north. In

fact the promontory on which the fori was built is hut thee tinuation of

Mount Independence, after an interval of 88 rods of water, and extends over

a mile farther northwestward.

This whole tract of historic ground consists of Calciferous strata, over 1,300
in thickness, dipping north at an angle of i; . The plateau on the
aorth end of Mount Independence is the top of division />'.- the thin-bedded
Bandstonee at the base of division C having probably been removed by glacial
action, not only here but also farther north, where Is now the basin of the
lake. The upper layers of />' .'ire largely quarried and \\-<A for a flux in the
iron furnace* On the New York side, in a steep cliff al the end of the

Am Jour. Si: I., 3d Si i ., Vol. Mil, 1877, p. 848.

STRUCTURE, ATTITUDE, AND FOSSILS. 507

promontory, appear the remaining beds of C — magnesian limestone inter-
stratified with sandstone. The ruins of the fort, 50 or 100 feet above the lake,
are on the mottled limestone at the base of B, containing Ophileta complanata,
Vanuxem, and a large Orthoceras. One hundred rods farther northwest,
the railroad tunnel is cut through the magnesian limestone of D, and above
the tunnel at the north end appears the banded sandstone of D. These and
the superjacent strata are best seen farther west on the steep southern slope
of the promontory, until finally, 40 rods southwest of the forks of the road,
we reach the drab limestone of division E, whose sudden change in dip
(N. 23° E.) and strike (N. 60° W.) indicates approach to some scene of
disturbance. Farther east, north of the main highway, there are other
exposures of the drab-colored limestone. These drab-colored limestones are
fossiliferous, carrying a form like Stenopora fibrosa, Goldfuss, Euomphalus,
aud uudescribed species of Orthoceras, Cyrtoeeras, and Lituites.

Southeast Charlotte Section. — Twenty miles north of old Fort Ticonderoga,
at Thompson's point, is another remarkable display of nearly all the members
of the Lower Silurian. It is another monocline, dipping from 12° to 20° to
the southeast. It is especially interesting, for in division D occur the Fort
Cassin series of rocks and fossils. In E are found the Cove islands, which
offer forms of Primitia.* On the bluffs on the shore, also, undescribed
species of Primitia are found in the strata underlying the Chazy.

Providence Island Section. — At Providence islaud, 24 miles north of
Thompson's point, there is an interesting exposure of the upper part of divis-
ion D and the lower part of division E of the Calciferous rock. The main
body of the island dips to the northeast, and successive beds are displayed
along the shore. Special points of iuterest connected with this section are
the occurrence of the Fort Cassin fossils in division D, represented by the
group Calaurops lituiformis, Whitf., Maclurea affinis, Bill., Lituites eatoni,
Whitf., Nautilus helloggi, Whitf., and the Shoreham fossils of E represented
by Murchisonia confusa, Whitf, Bucania triplet,, Whitf, Primitia seelyi,
Whitf., with undescribed gasteropods and cephalopods. The total thickness
of E, 450 to 500 feet, corresponds well with the thickness observed farther
south.

The Fort Cassin Strata.

In 1885 we found on the site of Fort Cassin, isolated on the peninsula at
the mouth of the Otter, a locality rich in a fauna chiefly new to science,
31 new species being distinguishable, with still others too poorly preserved
to be described with accuracy. This group then seemed to us more nearly
related to the forms we know in connection with the upper division of the

* Bulletin Am. Mus. Nat. His., Vol. II, 1878-'0o, pp. 58-60.

508 BRAINARD AND SEELY — THE CALCIFEROUS FORMATION.

Chazy I G). They were described in the Bulletin of the American Museum
of Natural History, Vol. I. No. 8, as Birdseye; and here we rested.

We arc convinced now that these Fort Cassin rocks, with their numerous
fossil forms, belong to the upper part of division D of the Calciferous. We
base our opinion on the frequent identity >f genera and species, the close
lithological resemblance with the rocks known to be of horizon D, and the
entire absence of the Fort Cassin rocks along the lake where the Birdseye
ought to appear it' it exists in Vermont.

The Canadian Exposures.

Brief reference may he made to the Phillipsburgh series, which extends
four or five miles into Vermont. Lagan's division A, with its three sub-
divisions, 700 feet in thickness,* is lithologically identical with our divisions
A, 11, ami C respectively of the Calciferous. The remarkable fossil, Criip-
iozoon gteeli (n. sp.), we have observed in the reticulated limestones of ^4 2
at Phillipsburgh. Similarly, the first four members of Logan's division B
correspond to our division D, both in lithological character and in fossil >.'<"
The beds of Calciferous sandstone are as prominent ami peculiar at Phillips-
burgh as at Shoreham. The magnesian \mU of our division E are, however,
but poorly represented in the lower part of Logan's division B 5, but in a
similar way they thin out and disappear in the eastern part of Addison
county, Vermont. The higher beds of B 5 at Phillipsburgh, and the beds of
C 1 seem to be represented in western Vermont, but by the lower beds of
the Chazy.

A Bimilar comparison might be made between the Calciferous of Lake
Champlain and the 1,830 feel of strata on the northwest coast of Newfound-
land (divisions 1) to L of the Geology of Canada). J

Misapprehensions ( Iorrected.

In connection with this discussion, various misapprehensions regarding
some of the rocks of Vermont should be mentioned and corrected. In the
Vermont Report, volume I. 1861, pp. 267-269, certain slates are described
as belonging to the < lalciferous group. < me exposure is cited in the exl reme
bhwesl corner of Shoreham, and another, farther Bouth, in Orwell, with
ledges running along the lake shore. The rocks in both of these Localities
have afforded fossils of the Qtica -late. So these slates of Vermont must
disappear from the ( lalciferous formation.

ol of > u ■ II.

• ■Ml., p|

I oit., p. 860, el Mq.

DEARTH OF SLATES AND BIKDSEYE ROCKS. 509

We have observed slate only in division E, and here it occm'S in thin
hands or layers, rarely carrying Ostracoda of different species.

Another point: Professor Emmons, in writing of the Birdseye formation,*
says :

" The name, it is true, is not very appropriate, and besides there are other lime-
stones to which the term Birdseye has been given, but they are not likely to be con-
founded with the Birdseye of the Champlain group."

But the mischief is that other rocks are thus confounded. A rock in B
of the Calciferous answers Professor Emmons lithological description of the
Birdseye, and Vanuxem j uses the very term in distinguishing a portion of
the Calciferous which is probably B, though he uses it to describe texture
and not to distinguish horizon. Again, the blue limestone of the upper part
of D of the Calciferous has the appearance and characteristic features of the
Birdseye, yet carries the abundant fauna of the Fort Cassin rocks.

A third horizon, below the true Birdseye, is that occurring in C, the upper
division of the Chazy. Calymene multicosta, Hall, and Ulcenus crassicauda,
Dalmau, found at Isle la Motte, are assumed in the Paleontology of New
York, volume I, 1843, pp. 228-229, to be in the Birdseye. They belong,
however, to the dove-colored limestones of the upper Chazy, which elsewhere
underlie strata over 75 feet thick, composed largely of Rhynehonella plena.
Calymene is found at the same horizon elsewhere on the lake. Cyrtoceras
boycii, Whitf., Soa (!) lamottensis, Whitf, and Liehas ehamplainensis, Whitf.,
belong also to the same bed of the upper Chazy.

The Birdseye formation is very scantily represented in Vermont. Phytop-
sis tubulosum, Hall, has been seen only in the northwest corner of Benson,
and in a bed only about six feet thick. Elsewhere we find in this horizon
only a few feet of pure, fine-grained, brittle limestone, with fine lines of calc-
spar, without fossils, lighter in color than the known Black River strata just
above.

Recapitulation and Suggestions.

As indicated at the beginning of this discussion, our study of the Calcifer-
ous formation has brought us a series of surprises. The first was the thick-
ness of the rocks. It was only after repeated measurements that we were
willing to accept the fact that we were dealing with a series of rocks but
little less than 2,000 feet in thickness. This, too, at a horizon where the
very existence of a formation worth the name was a matter of question.

The amount of maguesian limestone both surprised and perplexed us.
The masses of the various divisions are so alike that the attempt to place
them was at first discouraging ; but as we became familiar with the succession

* Geology of N. Y., Report 2d District, 1842, p. 1">7.
t Geology of N. Y., Report 3d District, 1842, p. 30.

LXVIII— Bill. Geol. Soc. Am., Vol. 1, 1880.

510 i : i : a i n a i: i » and si:i:i.v — tin: C a i.c i ii:i:< >i - FORMATION.

of fossil-bearing rocks interbedded with tbem the difficulty ina large measure
disappeared. They can besi be recognized by their relation to the super-
jacent and subjacent beds, their lithological differences affording unsatisfac-
tory distinctions.

amount of pure limestone was another surprise. These pure masses
are mosl uoticeable in division B; and the fact <>f its great abundance sug-

3ts the iuquiry whether a portion of the marble lying near the thinks ol
the Green mountains may not be metamorphosed Oalciferous.

A - iou in this immediate connection is that the sandstones and

sandy limestones of division C and those of the lower part of D gave the
name Calciferous to the formation. The fucoids, so far a- we have seen, art'
not characteristic of any one division, though they appear abundantly in
various horizons of D. Further. Scolithua cannot be regarded as indicating
a Potsdam" horizon, as the most abundant display that we have ever seen is
to he found at the bottom of division C,six or seven hundred feet above the
Potsdam sandstone.

A great surprise awaited us in the abundance of the fossil forms. The h>
and more genera, represented by over a hundred species, was an unlooked-
for result. Some limestone hands are packed with fossils; while the sand-
stones as well a- magnesian limestones, which at first were thought to he
barren, contain both obscure ami distinguishable fossils. The collection we
have made is to he regarded rather as a preliminary than a complete one.
A wide field for the study of paleontology is opened before u-. Forms
that were supposed to <'\i>t only at higher horizons are found to descend
more nearly to the primordial zone.

The discovery of Utica fossils in the .-late supposed to belong to the ( 'al-
ciferous simplifies the study of the formation by leaving out one perplexing
factor.

The- almost entire exclusion of the Birdseye formation from the Vermont
rocks was a result unexpected.

lie' exact horizon of the Fort ('a—in rocks seemed a simple problem, and
one we set ourselves to solve. Assuming the rock and fossils so like Birds-
eye to \>t- Birdseye, it appeared only necessary to find localities where the
upper Chazy approaches the Black river; and between would be the rock
ami the fossils we were Beeking. Hut in every such Locality we found the
Black river directly above the Chazy with no room for the Uirdseye. lint

we did find other exposures of the Fori < lassie rocks. And at what horizon :'
Challenging our belief with a sensation like a violent -hock, there appeared
Calciferous below, Calciferous above. These rocks then dropped down to

the upper member of division J), a fall of 1,000 feel ; and their fauna went

t" -well the increasing number of the < lalciferou

DISTRIBUTION OF THE CALCIFEROUS SEDIMENTS. 511

The fossils sometimes figured as sections of the stem of Phytopsis tubulosum,
Hall, and so regarded as indicative of the Birdseye, had previously been
shown by one of us to be really a little sponge, Strephochetus, not a Birdseye
fossil at all, but one characterizing the middle Chazy. So this perplexity
disappeared.

It must have been on lithological rather than stratigraphical grounds that
Calymene multicosta, Hall, and Ilkenus crassicauda, Dalman, were placed in
the Birdseye of Vermont. As has been previously stated, the rock carrying
these fossils belongs to C, the upper member of the Chazy, and is beneath 75
feet of Rhynclionella rock.

So the Birdseye has been retreating from Vermont, retreating upwards ;
crowded out form Calciferous B, Calciferous D, Chazy B, Chazy C, it finds
no standing room except over a few square rods within the state. With its
departure we are rid of a source of perplexity and confusion.

The correlation of the Calciferous of the Champlain valley with that of
the western states offers a subject for interesting investigation. This cannot
be entered upon here.

Attention may, however, be called to the distribution of the eastern Cal-
ciferous, which spans the country like an irregular bow from near Long
island to the island of Newfoundland, rocks of similar character appearing
in the valleys of the Hudson and St. Lawrence as well as that of the Cham-
plain, suggesting that the same physical conditions of sedimentation and
like forms prevailed from New Jersey to Labrador, the deposits marking the
position of an ancient sea beach not far from the borders of the Archean
terrane. The most magnificent development, however, appears in the
Champlain valley.

A suggestion may be offered in regard to names. In consideration of the
fact just stated — that of a wonderful deposit of a series of well characterized
rocks, 1,800 feet in thickness and bearing a fauna that will in all probability
soon reach up into the hundreds of specific forms, and this overlain by the
Chazy with its 700 feet of rock crowded in many parts of its three divisions
with distinct and characteristic fossils — may not the rocks of this group have
a name of their own rather than the misleading one " Canadian " ? They are
worthy of one.

In the time allotted, ouly an inadequate presentation of a subject so broad
could be expected. We must reserve to ourselves the right of taking other
opportunity aud other means of discussing the topic at a length its importance
demands.

Middlebury, Vt., December, 1889.

DISi USSION.

Mr. ( '. I> Walcott : The authors have stated in their paper thai the
Calciferous terrane lias a thickness of 1,800 feel in the Shorehara section,
between the Potsdam sandstone and theChazy limestone, and thai there are,
probably, Too feel of the < 'hazy limestone in the valley of Lake ( !ham plain.
Heretofore 300 or I"" feet of strata have been assigned to the Calciferous,
and not much more to the Chazy. One of the breaks in our knowledge of
the lower Pah >zoic rocks of the Champlain valley has been that which is
now covered so thoroughly by these sections.

Reference is made in the paper to the section at Pillipsburgh, Canada,
given by Logan in 1863. This section lias a thickness of 1,890 feet. The
base and summit of the section were not defined, as Logan * 1 1 < 1 not observe
cither contact. During the j>a-t summer I found, mi Lake Champlain, a
small outcrop of Potsdam sandstone, with characteristic fossils, subjacent to
the limestone of the Calciferous terrane. I measured the section through to
the summit of the Chazy /.one. ami it gave a thickness of 1,750 feet, with one
hiatus caused by a fault in the Calciferous portion. The Calciferous fauna
ranges through the lower portion of the section and passes into the Chazy
fauna about 1,400 feel from its base. It is impossible to draw any line of
division between the Chazy and Calciferous in the Pillipsburgh section by
stratigraphic or paleontologic evidence.

The authors state thai this series of rocks has been traced south to the
\ ■ w Jersey line and north to Phillipsburgh, Canada. During the past field

son I examined the Phillipsburgh section and then went to Quebec, on
the St. Lawrence, where the limestones have nearly all disappeared and the
-hales form most of the section. There i- a hand of limestone near the base
that carries the same fauna thai I found in the middle portion of the Cal-
ciferous part of the Phillipsburgh section. As the Point L6vis graptoli
occiii- in the .-hales immediately associated with the limestone, thi- identifies
the graptolitic fauna as of middle Calciferous age. In the bed of lim<
at Point Levis there are numerous fossils in the lighter colored lim< stones in
which I found fossils of the upper Cambrian or Potsdam age. Tracing the
Calciferous from New Jersey across Pennsylvania and Virginia into Ten-
le — ••> . we find the same series of rocks, which are there known as the Knox

dolomite. I crossed the section in Te «see a few weeks after studying the

Phillipsburgh Bection and recognized the upper Chazy zone, and then the
change of fauna thai passes into the Calciferous. At the base of the Knox
dolomite the upper Cambrian or Potsdam fauna is found in the Knox -hale
just a- it i- found, in the Phillipsburgh section, in the Potsdam sandstone at
the base of the Calciferous. The- Knox dolomite, I believe, is given a thick*

EQUIVALENCE OF EOLIAN LIMESTONE TO THE CALCIPEROUS. 513

ness of from 3,500 to 4,000 feet by Safford. These several sections prove
that in the Appalachian region, extending from Georgia to the St. Lawrence
river and also to Newfoundland, there is a great development of limestone
between the Potsdam zone and the Trenton limestone which may be referred
to the Calciferous-Chazy zone, or the Canadian period of Dana.

I think we owe to President Brainerd and Professor Seely our sincere
thanks for the valuable work they have been doing in the geology of the
valley of Lake Champlain.

Professor C. H. Hitchcock : Reference was made by Professors Brainard
and Seely to the work of their predecessors recorded in the geological report
of the state of Vermont. I was concerned in that, and I should like to ex-
plain a matter in reference to it, as I think perhaps the part we took is not
clearly understood. I was the assistant appointed for that portion of the
state at the very beginning of my scientific career, going directly from Pro-
fessor Seely's recitation room. With the limited means at our disposal we
made no effort to study these rocks thoroughly. We practically followed
through the Champlaiu valley the results of 'Adams and Thompson, who
preceded us, and therefore we did not see the great thickness of limestone
that is represented by these sections.

But there is another part of our work that I venture to take into account.
When we examined the limestones further east, which were called Taconic,
we came to the conclusion that they were practically the same thing as these
limestones directly on Lake Champlain, but we could not correlate them
because their thickness was so much greater, and therefore we gave to them
a special name — the Eolian limestone. The section of the Eolian limestone
corresponds with that given by the authors of this paper, being 2,000 feet in
thickness. The area in Shoreham was colored on our map as the Eolian
limestone, and thus we were in accord with these later conclusions, although
we used a different name.

THE FORT <ASSIX HOCKS AND THEIR FAUNA.

BY R. P. WHITFIELD.

[Read before the Society December 27 , 1889, as a Supplement /n tht Memoir "» the
Calciferous Formation in the Champlain Valley >>y Professors Brainard and Seely.)

About throe years ago, as was mentioned by Professor Seely, I published
in a Bulletin of the American Museum a series of fossils from Fori Cassia,
Vermont, and in that connection referred them to the horizon of the Birds-
eye limestone, partly on paleontological grounds, and to some extent on the
apparent Btratigraphical relations of the beds in which they were found.

When the fossils came to me first, they were thought to be from the Tren-
ton limestone, but on a cursory examination I could find no species among
them which I could identify with any Trenton forms that I had ever seen.
After studying them, I visited Fort Cassin in company with Professors
Brainard and Seely. and spent about three hours at that locality. In look-
ing at the beds then I became convinced they could not be true Trenton;
also that they could not be very much lower in the series. After examining
the rocks at that point we visited the Maclurea l>eds Mt a locality (Apple-
tree point) 63 rod.- further north, and the next day another locality four
miles to the south. This lasl proved to be Trenton limestone, and contained
Trenton fossils.

The Fort Cassin beds are characterized by a fauna consisting largely of
cephalopoda, with many gasteropoda and a few brachiopods. One of the
cephalopoda appeared to be identical with the form described by Professor
Hall as Orihoceras bilineaium, and referred to the Birdseye limestone.
The general character of these fossils appeared to be the Bame as thai of
those from the lower pari of the Trenton group, namely, the Black River

or Birdseye limestone; and the character of the Lituites, ■ of which

were, however, identical, was also \<rv similar. Th 'thocerata, other

than 0. bilineatum, Hall, were entirely new, and the occurrence of Qompho-

,,,<i- in these beds was a very peculiar feature, at leasl for an American

locality, as it had not hitherto been found below the Niagara group. The
jteropods were as pecu liar in their character as the cephalopoda, and we
have a number of genera, all of which characterize the Trenton group
throughout, except Maclurea, and none of which had been found below the
Chazy limestone, except by the Canadian geologists, who referred them to
the Quebec group. Among these were a number of nearly identical, or

114)

CONFLICT OF STRATIGRAPHY AND PALEONTOLOGY. oli")

what might be called representative, forms of those described from New-
foundland, and referred by both Sir Willam Logan and Mr. Billings to the
Quebec group. But from the fact that of so many of the forms referred to
the Quebec, the true horizon of which is doubtful, it seemed best not to con-
sider them as of stratigraphical value.

A few of the species were also similar to forms from the Phillipsburgh sec-
tion, which Logan referred to the Quebec and Billings to the Calciferous.
After studying these fossils I concluded they were more nearly analogous to
those of the lower Trenton than to anything below that horizon, and after
examining the Fort Cassin section it appeared as if they could be but little
above the Maclurea beds of the Chazy, as the Calaurops layer, which is
fifteen feet below the Fort Cassin fossil layer, appears by the Fort Cassin
section to come just above the Maclurea beds of Apple-tree point, 63 rods
further north ; and no other explanation can be given of this without the
supposition of a fault occurring between these two points.

Taken from a paleontological point of view, based upon the previously
known faunas exclusive of those referred to the rather troublesome Quebec
group horizon, it would appear impossible to place these beds at any horizon
other than that of the base of the Trenton group, namely, the Birdseye lime-
stone. But from evidences brought forward by President Brainard and
Professor Seely, as shown in their Ticonderoga and Shoreham sections, it
appears that they are undoubtedly below the Maclurea beds of the Chazy
limestone, and that a fault must exist where none was suspected.

My object in calling attention to this matter at this time and in this way
is chiefly to make a correction of the reference of this group of fossils and to
have it placed on record as such. But whether the beds are to be called
Calciferous or not will depend entirely upon where the line between the
Calciferous and the overlying Chazy shall be draAvn. A visit with Professor
Seely, a year later, to Beekmantown, New York, on the opposite side of the
lake, a few miles north of Plattsburg, where the true Calciferous, well de-
veloped and abundantly characterized by its own fossils, the Ophileta com-
planata and accompanying gasteropods, failed to show anything of the Fort
Cassin fauna.

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA

VOL. 1, PP. 517-593

PROCEEDINGS OF THE ANNUAL MEETING HELD AT

NEW YORK

DECEMBER 26, 27 AND 28, 1889

J. J. STEVENSON, Secretary

( With Index, Contents, etc., of Volume 1)

NEW YOEK
PUBLISHED BY THE SOCIETY
May, 1890

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA
Vol. i, pp. 517-593. May 27, isoo

PROCEEDINGS OF THE ANNUAL MEETING HELD AT NEW-
YORK DECEMBER 26, 27 AND 28, 1889.

J. J. Stevenson, Secretary.
CONTENTS.

Page.

Session of Thursday, December 2G 518

Obituary Notices 519

The Laramie Group (abstract) ; by J. S. Newberry 524

Note on the Eruptive Origin of the Syracuse Serpentine ; by George H.

Williams 583

Session of Friday, December 27 585

Report of the Council 535

On the Tertiary Deposits of the Cape Fear River Region ; by William 13.

Clark 537

Glacial Features of Parts of the Yukon and Mackenzie Basins; by R. G.

McConnell 540

A. Moraine of Retrocession in Ontario (abstract) ; by Rev. G. Frederick

Wright 544

The Southern Extension of the Appomattox Formation (abstract) ; by

W J McGee 54G

Session of Saturday, December 28 550

Geological and Petrographical Observations in Southern and Western

Norway (abstract) ; by George H. Williams 551

Cretaceous Plants from Martha's Vineyard (abstract); by David White— 554
Significance of oval Granitoid Areas in the lower Laurentian (abstract) ;

by C. H. Hitchcock 557

Porphyritic and Gneissoid Granites in Massachusetts (abstract); by B. K.

Emerson 559

On the Intrusive Origin of the Watchung Traps of New Jersey (abstract) ;

by Frank L. Nason 562

The Fiords and Great Lake Basins of North America considered as Evi-
dence of Preglacial Continental Elevation and of Depression during

the Glacial Period ; by Warren Upham 5f'.3

On the Genus Sjnrifern and its Interrelations with the Genera Spiri-

fe.rina, Syringothyris, Cyrtia, and Cyrixna (synopsis); by James Hall. 567
On Pot-Holes North of Lake Superior unconnected with existing

Streams; by Peter McKellar 568

Constitution and By-Laws of the Geological Society of America 571

List of Officers and Fellows of the Geological Society of America 579

Index to Volume 1 587

LXIX— Bull. Geol. Soc. Am., Vol. 1, 1880. (517)

Session of Thursday, De< ember '2i'>.

The Society mel in the American Museum of Natural History : President
James Hall in the chair, and a large number of Fellows and guests present.

The Presidenl called the Society to order al LO 40 a. in., and introduced
Morris K. Jesup, Esquire, President of the American Museum of Natural
History, who welcomed the Society and gave a brief statement respecting
the character and purposes of the Museum, showing how closely it is related
to w<>rk Buch as is done by the Geological Society. President Hall replied.
acknowledging the courtesy of the Trustees of the Museum, and recalling
some interesting facts to show the early prominence of New York as a sei-
entific center.

The minutes of the meeting held at Toronto on August 28, L889, were
read by the Secretary and approved : after which the report of the Treasurer
was read. It showed a balance of $1,716 in the treasury.

The Secretary read the results of ballot for new fellows, as follows:

Frank Dawson Adams, Montreal, Canada, lately of Geological and Natural His-
tory Survey of Canada, new Lecturer at McGill College, Montreal.

Victor Clifton Alderson, 6721 Honore Street, Englewood, [11., Teacher of Ge-
ology.

Henry M. Ami, Ottawa, Canada, Assistant Paleontologist to Geological Survey of
Canada.

Albert Smith Bickmore, American Museum of Natural History, New fork city,
formerly Professor of Natural History at Madison University, new Professor of
Natural History, Curator of Anthropology, ami Secretary of the American
Museum of Natural History, and engaged in lecturing on Geology and Physical
* I igraphy.

Ezra Brainerd, Middlebury, Yt., Presidenl ofMiddlebury College.

Aaron Hodgman Cole, Hamilton, X. Y.. Lecturer on Natural History al Madison
University, ami now engaged in Study of Invertebrate Paleontology.

Thomas Sterry Hunt, New York city, formerly of Geological Survey of ('ana. la,
now engaged in Chemical Geology.

11. i>. Lacob, Paleobotanist, Pittston, Pa.

Alfred Church Lane, Houghton, Mich., Assistant on Geological Survey of Mich-
igan, ami engaged in Petrography.

Daniel Webster Lanqdon, Jr., Cincinnati, O., formerly Assistant on the Ala-"
bama Survey, now Geologisl of Chesapeake and Ohio Kail way Company.

A i.i Kin Richard I !eci l Selwyn, Ottawa, < 'ana. In. Director of the Geological ami

Natural H'lBtory Survey ..I' Canada.

Swallow, Helena, Monl . formerly State Geologist of Missouri

and also of Kansas, now [ns] tor of Mines of Montana.

Bailed Willis, Washington, !».•'.. in charge of the Appalachian Division of the
I '. s. Geological Sun ny.

18)

OFFICERS FOR L890. 519

J. E. Wolff, Cambridge, Mass., formerly Assistant on N. Transcontinental Survey,
Assistant in N. E. Division of the U. S. Geological Survey, now Instructor of
Petrography at Harvard College.

Lorenzo G. Yates, Santa Barbara, Cal., Botanist, engaged now in Study of Fossil
Mammals of Pacific Coast, respecting which he has published numerous papers.

The result of ballot for officers for 1890 was announced as follows:

James D. Dana, President.
John S. Newberry, )

Alexander Winchell, / Vice-Presidents.

John J. Stevenson, Secretary.

Henry S. Williams, Treasurer.

J. W. Powell, ^

George M. Dawson, V Members-at-large of the Council.

Chas. H. Hitchcock, J

The Secretary announced the death of three Fellows of the Society,
George H. Cook, David Honeyman, and Charles A. Ashburuer. He was
authorized to publish the following notices in the Bulletin :

OBITUARY NOTICES.

Professor George H. Cook died suddenly of heart failure on September
22, 1889. He was born at Hanover, New Jersey, on January 5th, 1818.
In 1836 he became a civil engineer, and his first work was in laying out
the line for the Morris and Essex railroad. He also surveyed the line for
the Catskill and Canajoharie railroad. He was not, however, satisfied with
his attainments, and entered the Troy Polytechnic Institute in 1838, grad-
uating in 1839. He afterward became a teacher in the institute, and in
1842 he was made " senior professor," an office equivalent to that of presi-
dent elsewhere. He afterward became professor of mathematics and natural
philosophy in the Albany Academy. In 1851 he became principal of the
academy, and held the office two years, until his election to the chair of
chemistry and natural philosophy in Rutgers College. The next year he
was made assistant geologist of New Jersey, which position he held for three
years. The office of state geologist had been allowed to lapse for several
years, but a paper read by Professor Cook before the legislature, in 1864,
led to its reorganization and to his appointment as its head.

Professor Cook's work as state geologist was varied and of great impor-
tance. The topographical maps of the state which have been published
under his supervision have been adjudged to be among the best published
by the different states. The last of the series was recently issued, and

.".•JK PROCEEDINGS "1 NEW YORK MEETING.

Professor Cook was at the time of his death engaged on bis final report
Two volumes had been prepared and are now in print.

In 1864 the State Scientific College was attached to Rutgers College, and
- : l k, while retaining his professorship, became vice-president ofthe
state collegi . He organized the State Board of Agriculture, and was for a long
time its secretary. He became in 1886 chief director ofthe New Jersey State
Weather Service. He was long president of the New Brunswick Hoard of
Water < Joramissioners. He was also a member of the State Board of Health,
and laid many minor offices in the state. He was active also in work eh
where. In 1852 he was sent to Europe by the state of New York to make
investigations that might aid in developing the Onondaga salt springs. He
went again to Europe in 1870 to study certain geological questions. He
was a member ofthe National Academy of Sciences, and the author of many
papers and addresses. He received the degree of Ph. D. from the Uni-
versity of New York, and the degree of LL. D. from Union College.

" A friend whose devotion never waned, a loyal citizen ready for every
duty, a true scientist and a manly christian, he has left an example for us
if we would make the world better and wiser."

Rev. David Honeyman, D. C. L.,* was born at the village of Rathillet,
in the northern part ofthe county of Fife, Scotland, iu the year 1*14. He
was educated at the University of St. Andrews, on the east coast of the
same county. At college he devoted special attention to Hebrew, and was
early recognized as a Hebrew Bcholar; but, even in youth, his attention was
attracted to geology, as was that of many other young men in the locality.
at a time when Sir Charles Eyell was laying the foundations of his life
work (one of his earliest publications being a geological section of the ad-
joining county of Forfar) and Hugh Miller was developing the paleonto-
logies! riches of the Did Red Sandstone rocks of the northern shoi

Honeyman's firs I geological work was in connection with the Museum of
the Watt Institution of Dunde le of the early Scotch " mechanics' insti-
tute i" which he, in conjunction with other.-, brought together and ar-
ranged collections of mineral and rock specimens and fossils. In 1851 he
hft Scotland for Nova Scotia, ami took the chair of Hebrew in the Halifax
Free Church College. After a brief term al Halifax he accepted the pas-
torate of the Presbyterian congregation of' Shubenacadie, in the Bame prov-
ince, and. the leafier, that of A nt i -_r < • 1 1 i .— 1 1 , from which he was released in 1 859.

After this retiremeul he continued to conduct services occasionally, Inn did
nol accepl a -tiled charge, devoting his time chiefly to geological and cither

OBITUARY NOTICES. ~>'ll

scientific work. He examined particularly the geology of Cape Breton and

the eastern counties of Nova Scotia, paying special attention in later years
to glaciation and transported materials. Many of his observations were
published in the Proceedings of the Institute of Natural Science of Nova
- >tia. Much of his work was brought together, a few years ago, in a small
work entitled "Giants and Pygmies."

Dr. Honeyman acted as executive officer of the Nova Scotia government
at several of the great international exhibitions held in the United States
and Europe, at which the products of Nova Scotia were shown. He was
for many years curator of the Provincial Museum at Halifax. He deliv-
ered several courses of lectures on geology in Dalhousie College, Halifax.
The University of King's College, Windsor, Nova Scotia, conferred upon him
the degree of D. C. L.

On Thursday, the 17th October last, he closed the museum as usual at 4
p. m., chatted in his customary lively manner with those he met on his way
home, when he was seized with apoplexy and dropped on the sidewalk. He
recovered consciousness momentarily and remarked, " That was very sud-
den ; " but, within ten or fifteen minutes, although in the hands of two able
physicians, he passed away, leaving a sorrowing widow and four daughters.
His remains were accompanied to the Halifax cemetery by a very large
procession of leading citizens, on Sunday, 20th October.

G. L.

Charles Albert Ashbtjrner, Sc. D. (University of Pennsylvania),*
was born in Philadelphia, February, 1854, and educated at the Friends'
Central School, and the Philadelphia High School. In 1870 he entered the
Towne Scientific School of the University of Pennsylvania, and was grad-
uated in 1*74, at the head of his class, delivering the valedictory on com-
mencement day.

While an undergraduate he was one of the aids on a hydrographic survey
of the Delaware river. After graduation he served in the U. S. Light-Hou-e
Survey Corps; and was commissioned, in 1874,aid to Mr. John H. Deuces,
Assistant Geological Survey of Pennsylvania for the Juniata river district.
With his classmate and fellow aid, Mr. G. E. Billin, he made a contour line
survey of the southern slope of Jack's mountain, and the underlying vales,
to determine the outcrops of Clinton fossil ore beds, extending from Lewis-
town south to Orbisonia, and west to the summit of the East Broad Top
coal basin. Maps and many beautifully constructed measured cross-sections,
local maps of the fault in Black Log gap and of the curious downthrow at

* By J. P. Lesley.

11 PROCEEDINGS OF NEW YORK MEETING.

■>1J.

Three Springs, etc., w«re published in Report F, in L878, its illustrations of
their excellent geological and topographical work. Mr. Ajshburner's sensible
ami full report of it, supplementary to and separate from the special report
of Mr. Dewees on the ore, will be found in the last half of the volume.

Saving thus shown great ability in reading and portraying the geology
of one difficult district, Mr. Ashburner was commissioned in ls7'i to survey
McKean, Elk, Cameron, and Forest counties on the northern border of the
state, where the development of the petroleum production in the Bradford
field was becoming of extraordinary importance, soon to overshadow that
of all other oil fields previously or subsequently exploited. This survey
occupied him and his aids two years, and his able report upon it (R) was
published in 1**0, well illustrated with local maps and sections, a colored
geological map of each county, and a topographical map of McKean county
in contour lines. His second report (R 2) on Elk, Cameron, and Forest
counties, published in 1885, exhibited broad views and sound deductions
from surface facts and horing records, which became of great importance to
the community, and started him on a career of oil and gas investigation
which afterwards extended over a large part of the United State- and Can-
ada. His determination of the various rates of increment of the formations
intervening between the conglomerate above and the oil-bearing Chemung
below had much influence on the depths to which subsequent experimental
borings were carried. His differentiation of the conglomerate was also an
important contribution to geology.

In 1880 he was directed to go to the eastern part of the state and plan a
survey of the Anthracite region as a whole; and in 1881 he organized a
complete corps of assistants, established offices at four centers, and began
the systematic survey which has shed such lustre on the Geological Survey
of Pennsylvania. Its successful prosecution, in one basin after another,
year after year, until he tendered his resignation in L887, was due entirely
to his genius for geological work of the highest order, to his disciplined
judgment in dealing with men of all ranks and occupations, to his high
sense of personal honor, and to his kindness of heart.

In the fall of 1886 he resigned his commission to become the scientific
expert of the VYestinghouse Fuel Gas aud Electrical Engineering Company
at Pittsburg, for which he visited various districts of the United States

which the universal search for natural gas IU turn invaded; and he thus
became an authority of the first rank in this branch of geology.

He was also required to pass judgment upon properties on which mining
of the precious metals was proposed, especially in the far west. <>n his Last
return from the copper district of Arizona he fell ill ami suddenly died,
I » scember 2 I. 1 $89, in the thirty-sixth year of his age, universally esteemed
and respected in his profession and in private life.

PAPERS BY CHAMBERLIN, SHALER, AND BELL. 523

His principal record was made by his reports to the state geologist of
Pennsylvania, but he published many papers in the transactions of the
American Institute of Mining Engineers, of which he was a zealous mem-
ber and officer; as also of the American Philosophical Society, American
Society of Mechanical Engineers, Academy of Natural Sciences, American
Geological Society, and American Association for the Advancement of
Science.

J. P. L.

Some general announcements were made, after which the President an-
nounced the first paper of the meeting, entitled —

SOME ADDITIONAL EVIDENCES BEARING ON THE INTERVAL BETWEEN THE

GLACIAL EPOCHS.

BY PRESIDENT T. C. CHAMBERLIN.

The communication was discussed by Mr. W J McGee, Professor John R.
Procter, Professor I. C. White, Mr. F. J. H. Merrill, and President Cham-
berlin. The communication and discussion are printed in full among the
memoirs, forming pages 409-480 of this volume.

The Society then listened to a paper on —

TERTIARY AND CRI<:TACEOUS DEPOSITS OF EASTERN MASSACIJUSKTTS.

BY N. S. SHALER.

This communication was discussed by Mr. G. K. Gilbert. It will bo
found among the accompanying memoirs, pages 443-452.

In the absence of the author, the next paper was read by title:

ON GLACIAL PHENOMENA IN CANADA.
BY ROBERT BELL, B.A.SC, M.D , LL.T)., ETC.

It will be found printed in full among the memoirs, pages 287-310.

After a short recess the Society reassembled and listened to the oral com-
munication represented by the following abstract:

illi: LARAMIE GROUP.
BY .1. s. NEWBERRY.

(Abstract.)

The Laramie group was named by Mr. Clarence King and defined in his "Sys-
tematic Geology," volume I of the Report on the Geology of the Fortieth Parallel,
L878. The name was accepted by Dr. Hayden bul differently applied, since, contrary
to the usage and judgment of Mr. King, he included in it the Fort Union group.
Dr. Hayden at first called his compound Laramie Tertiary, but he subsequently desig-
nated it post-Cretaceous.

The Laramie group proper, as defined by King, consists of a series of Bhales, sand-
stones, and I"-'!- of coal, largely developed in Colorado, Utah, and Wyoming. It is
well exposed on the east Bide of the Rocky .Mountains in a belt that reaches as far

north and south as explorations have I n made I have myself traced it nearly to

the southern line of Chihuahua and as far north as the Canadian boundary : through-
out this region it is a greal coal-bearing belt. Along tin' line of tin' Pacific railroad
it is exposed at Point of Rocks, Black Butte, Bitter Creek, Evanston, and elsewhere,
and tli>' coal mini'- at the-'' places are -ill opened in it. On the west side of the Rocky
Mountains also it is coal-bearing, and is known to extend interruptedly from the San
Juan river to and beyond the Union Pacific railroad. At Crested Buttes, Coal Basin,
Newcastle, and other points it contains a number of thick and very pure coals
which vary in character from hard, bright anthracite to non-coking bituminous coals,
this variation being dependent upon igneous rocks which sometimes cut through,

times underlie, and sometimes have overflowed the coal beds. Pr tin' Rocky

Mountain- in < lolorado th^ Laramie extends westward to the Wasatch, and everywhere
contains beds of coal, some of which have been worked at Cedar City, Castle Valley,
Pleasant Valley, Coalville, and elsewhere.

'I'll'' Laramie formation has in the Raton mountain, according to Mi-. R. c. Hills,
a thickness of nearly 6,000 feet. At Trinidad, Walsenburg, Florence, and north of
Denver at Marsballs's and at Erie, in all of which localities its coals are worked, it
i- much thinner, the upper portion having been removed by erosion. In Table
mountain, near Golden, this upper portion ha- been protected by a trap overflow, and
a thickness of perhaps 3,000 feet of strata is shown, all of which belongs to the Lara-
mie. <>n the west Bide of the K"*'ky Mountain-, at Coal Basin, Newcastle, and ''1-''-

whore, the La rami'- shows a thicki of from 8,000 to 1,000 feel The beds are hero

highly inclined; hut in Monument up '-a. between Grand river and the Gunnison, the
strata are nearly horizontal and are overlain unconformably by fresh-water Tertiary

The relations "I the Laramie group have 1 n much discussed, and perhaps no por

• , of the geological column of North America has given rise ton greater amount "i

literature or a greater diversity of opinion among geologists. This, for the most part,
arisen from the fact that many writer- on tin- subject have combined two distinct

formations in the Laramie and have called them one. when they have almost nothing

in common, belong to different geological systems, and should never hav 3 boon united,
h K. V . Hayden, who spent so many years in studying the geology of tho country

bordering tl IT'"' N' '' made large collections of fossil plant- from the Port

J. S. NEWBERRY THE LARAMIE GROUP. 525

Union group at Fort Union, on Tongue river, on Amil's creek, and in other places, all of
which he placed in my hands for study. Most of these 1 described in the annals of
the New York Lyceum of Natural History in 1869. I called this flora Tertiary, and
made it Miocene because I identified in it many species of plants collected on Macken-
zie river, in Greenland, Spitzbergen, and various European localities described by
Professor Oswald Herr in his Flora Fossilis Arctica, and called there Miocene, but
since shown by Mr. J. Starkie Gardner to be Eocene.

Mr. Leo Lesquereux, who was for many years employed by Dr. Hayden to work
up the plants collected by the different parties of the Geological Survey of the Terri-
tories, following Dr. Hayden, united the Laramie and Fort Union and called the
Laramie Eocene and the Fort Union Miocene. Mr. Lesquereux described in Dr.
Hayden's annual reports and in volumes VII and VIII of his final report a large
number of fossil plants from the Laramie, collected at Placer mountain, New Mexico,
the Raton mountains, Fisher's peak (Trinidad), Golden, Marshall, Point of Rocks,
Black Butte, and other points. As has been stated, he regarded this flora as Eocene,

In the Sixth Annual Report of the Director of the U. S. Geological Survey (1885)
Professor Lester F. Ward published a " Synopsis of the Flora of the Laramie Group."
Like Dr. Hayden and Mr. Lesquereux, he unites the Laramie and Fort Union groups
and calls them Tertiary but, unlike Mr. Lesquereux, considers the whole Eocene.
Professor Ward's material, chiefly collected by himself in the valley of the Yellow-
stone, is mostly from the Fort Union group, and so his memoir is really and only
an important contribution to our knowledge of the Fort Union flora.

In 1875 Professor E. D. Cope discovered in the Laramie group, at Black Butte,
the bones of a saurian which he called Agathaumas sylvesire. Between and around
the bones of this saurian were numerous fossil leaves. Professor Cope pronounced
his saurian to be of Cretaceous age, and accepting Mr. Lesquereux's view that the as-
sociated flora was Tertiary he says, in the second volume of the final report of Dr.
Hayden (page 40) :

" There is then no alternative but to accept the result that a Tertiary flora was contemporaneous
with a Cretaceous fauna, establishing an uninterrupted succession of life across what is generally
regarded as one of the greatest breaks in geologic time."

This paragraph has been frequently quoted, and has been considered by some as
proof that the testimony of plants was inconsistent with that of animal remains, and
that plants were of little value in deciding the age of strata. Since the publication of
Professor Cope's report here referred to I have spent much time in the study of the
structure and fossils of the Laramie group in New Mexico, Colorado, Wyoming and
Utah. I have made and had made larger collections of the plants of the Laramie
than had before been gathered by any one ; have compared them carefully with the
flora of the Fort Union group; and in two visits to Europe have examined all the
principal collections of Tertiary and Cretaceous plants made in England or on the Con-
tinent, largely for the purpose of solving the problem of the age of the Laramie as
compared with other more or less closely associated formations in this country and in
Europe. My purpose in coming before you to-day is to briefly report the results at
which I have arrived ; and these are: —

First. That the floras of the Laramie and Fort Union groups are totally distinct,
and these formations should be referred to different geological systems— the Fort Union
to the Tertiary, the Laramie to the Cretaceous.

I have not myself seen a single species common to these floras, and but one has
been reported by others, viz., Trapa mierophylla, found by Lesquereux at Point of
LXX— Bull Geol. Soc. Am., Vol. I, 1889.

526 PROCEEDINGS OF NEW YORK MEETING.

Lock-, ami collected by Professor Ward in the valley of the Yellowstone. It does
not occur in tlic collection of Fort Union plant* placed in my bands by Dr.
Eayden, nor in the large representation of this flora which I have obtained from
other sources. Mr. Lesquereux bad but little material, bo little that I think it would
be unwise to hang an important conclusion upon it; but if it sin mid prove that the
plants collected by Mr. Lesquereux and Professor Ward are identical, that would be
no good reason lor uniting floras that are so different in aspect and consist of hundreds
of species which are unlike-.

id. The Fori Onion flora may be distinguished from that of the Laramie at a
glance by its abundant Bpecies of Viburnum, Populus, Plaianua, and Gorylus, and it
includes several species now living, such as Onoclea sensibilis, Taxodium di&tiphum,
and two hazels which cannot be distinguished by their leaves from Gorylus rostrata
and C. americana. It has also the general facies (and several identical species) of the
Eocene flora of Bournemouth and the Island of Mull, and should undoubtedly be
rred to the same horizon.

Third. The Laramie flora is most like the Paleocene floras of Sezanne, Galinden,
and Alum hay. but it is not certain that any of its species are identical. Two fern-.
I ■ ■ laeea, Saporta, and Lygodium kaulfussi, Herr, are considered by Mr. J.

Starkie Gardner the same with Lesquereuz's Qymnogramme haydeni and Lygodium
les. This is possible and perhaps probable ; but our plants are more robust
than the European and may he considered as distinct varieties if specifically identical.
It should also be said that both these ferns have wide geographical and vertical range
and are believed to occur in both the Cretaceous and Tertiary strata ol the old World.
Hence they have little value as means for determining the age of the Laramie. I
have fronds of Lygodium which I cannot distinguish from the type of L. neuropieroides
obtained from the lower Laramie, the Green River group, the Currenl creek beds of
Oregon, and the coal-bearing strata of Wikinson, Washington ; hut the fronds of this
genus are very variable in form, and it is quite possible thai my specimens represent
era! species. So] have what Mr. Gardner would probably regard as fronds of
Anemia suberetacea from Point of Rocks, Ham's fork, Carbonado, and Tschucker-
nuts, Washington ; but most of these are much more robust than the European forms,
and constitute at least distinct varieties.

/ vrth. The Fort Union flora contains a large number of species found by the
Canadian geologists in the "Porcupine Hills" or "Paskapoo" series of rocks, and
it is quite certain that they are of the Bame age ; while the " Edmonton series" of
Canada is as surely identical with our Laramie. Dr. Dawson'- Belly River series also
contain- a number of Laramie plants but it is overlain by marine strata containing

1' . Hills Husks. This is a strong argument in favor of the Oretai us age of the

Laramie, and indicates that the Laramie flora was established on the land while the sea
near by was peopled with Cretaceous mollusks; that, locally and temporarily the sea
invaded the land and laid down marine upper Cretaceous beds over brackish or fresh-
water Laramie sediments, afterward retreating bo thai the Burface was again cc\ ered
with Laramie vegetation. The interlocking of the Laramie and Fox Hill- formations
i- also -hown in the Judith river basin and in southern and western Colorado, where

/ 'amus, Mactra alta and Cardium speciosum ;ur with Laramie plants.

I f now to th we add the occurrence in the Laramie of many genera and species

of dino-aiir- and man;, -mall mam M ozoic character, a- .-hown hy Professor

M mh, the weight of evidence in favor of the Cretai us age of the formations is

rwhelmlng. This view was long ago advocated by Mr. Clarence King. Mr F. B.

J. S. NEWBERRY — THE LARAMIE GROUP. 527

Meek, Professor J. J. Stevenson, and myself, and the arguments in favor of it have
recently been much strengthened.

The relations of the Laramie group to the coal-bearing rocks of Puget sound and
Vancouver island are very intimate. They have many species of fossil plants in
common, and it is certain that a considerable portion of the ten thousand feet of coal-
bearing strata on Puget sound is of Laramie age. The upper part of the series at
Bellingham bay contains some Fort Union plants and is doubtless Tertiary.

The relations of the Laramie to the " Lignjtic " groupof Mississippi are as yet doubt-
ful ; a few species of fossil plants are apparently common to both, but the molluscan
fauna is entirely distinct. It is to be hoped that the able geologists now at work with
so much success in Arkansas and Texas will make collections of the Lignite flora
that will permit full comparisons to be made with the flora of the Laramie.

In conclusion, I would say that an effort has been made to distinguish the Laramie
from the Fort Union group by assuming that the mollusks of the Laramie are marine
or brackish water, while those of the Fort Union are fresh-water species. This dis-
tinction will not hold ; for at Cedar City, Utah, one of the coal seams of the Laramie
group contains and is overlain by sheets of fresh-water marl composed of shells of
U/tio, Goniobasis, Physa, Paludina, etc., and above these is a stratum of calcareous
sandstone containing Inoceramus and a bed of oyster shells four feet in thickness.

Professor E. D. Cope : I would like to ask what the geographical extent of the
Fort Union beds may be ?

Dr. Newberry: I do not think that question can be answered fully, because there
is a large area in Wyoming and Montana which has not yet been explored. The
southern limit of the Fort Union group and its contact with the Laramie may perhaps
be found in that section. In Colorado I have never seen any Fort Union strata.
They extend far into the Canadian territory, as they have been recognized in many
localities by the Canadian geologists, and have been called the " Porcupine Hills " or
" Paskapoo " series. In Mr. Tyrrell's report for 188G (on northern Alberta) you will
find an interesting discussion of this question, and a list of the plants of the Paskapoo
beds is given. They are all Fort Union species. The t; Edmonton series " is appar-
ently the representative of part of our Laramie.

Professor Angelo Heilprin: I would like to ask Professor Newberry whether,
acccording to the interpretation which he has given, the Laramie, as a Cretaceous
formation, disappears; and, if this is the case, I should like further to ask what hori-
zon in the Cretaceous the Laramie represents — whether it is the equivalent of what
has always been considered the uppermost Cretaceous or whether there is something
imposed upon it? So far as I have seen, from the evidence that Professor Newberry
submits, the link between the Cretaceous and the Tertiary totally disappears.

Dr. Newberry : In my judgment the Laramie is the top of the Cretaceous system.
I do not know why it should be called post-Cretaceous. It is true there must be
somewhere connecting links between the Cretaceous and Tertiary, as the streams of
time and life have flowed on continuously and geological agents have been acting
incessantly. So we shall ultimately find passage-beds bridging the interval between
the Mesozoic and Cenozoic ; but I know of no evidence that the Laramie is such a
passage-bed. In the lower part it contains Fox Hills fossils, and thus is linked to the
Colorado group, but if we separate it from the Fort Union group it has really no con-
necting links with the Tertiary.

The physical history of the Cretaceous system in the interior of the continent is

528 PRO( BEDINGS OF NEW YORK MEETING.

briefly as follows : In the region now bordering the Gulf of Mexico on the south and
• during the first half of the Cretaceous age marine conditions prevailed, and in tin-
sea of that time and place several thousand feet of limestone were deposited — the
Comanche group of R. T. Hill and Dr. White ■ Most of our continent was out of
water during the long interval asured by the deposition of the Comanche lime-
stones, but about tin- middle of the Cretaceous age the sea rose over its shores and
submerged all 1 1 1 « - great depressed area between the Alleghany and Canadian high-
land- on the east and the Rocky Mountain- and Wasatch on the west. When the sea
invaded this area it- shore wave- spread a sheet of sea beach, the Dakota sandstone
serie-. as far a- the submergence extended. A- the water deepened over the area of
the plains, marine sediments were laid down on the Dakota ; in the open sea, lime*

2 i feel or more thick — the Fort Benton, Niobrara, Fort Pierre, and V<>\ Hills

groups of Meek and Hay den. Near the western shore of the Cretaceous sea the sedi-
ment- were more earthy, shales alternating with concretions and continuous beds of
limestone, and in places 2,000 feet or more of bituminous -hale. In the mountains of
New Mexico, Colorado, and Wyoming the divisions of Meek and Hayden's upper
Missouri -ection cannot be identified, and so Mr. Clarence King called the strata
immediately above the Dakota the Colorado group. At the top of this we find a

sudden change of sediments, sandstone and .-hale- with beds of coal suc< ding the

bituminous shales and lime-tones. This is the Laramie. There is no unconform-
ity here except what may be due to erosion and such as we always or often lind
where strata of coarse material-, sandstones and conglomerates that have heen
deposited by rapid current-, rest upon fine ami quiet-water sediments. The Laramie

is tied to the Fox Hills by BOme of its fossils, and the heavy sand-ton- which lies at

its base in southern Colorado and New Mexico has heen called by Professor Stevenson
the Fox Hills sandstone, but it seem- to me better to begin the Laramie with the
change of sediments rather than attempt to maintain the identity of the Fox Hill-
group in this region. The epoch of the Laramie was one of disturbance, at least of
local oscillation of water level. The sandstones are shore deposits, the -hale- -hallow
water sediments, and the numerous coal beds were formed under BUbaerial condition-,
and they are remarkably local. Sections quite near each other show great differences
in the number, relative position, and thickness of the coal -earn-. This means frequent
and local changes of level. The coal seams give the Laramie group greater economic
importance than any other formation in the middle and western parts <>i' the continent.
It i- generally coal-bearing, and it- coals are in some places of remarkable thick'
and purity. Probably no equal area in the world rival-, in the quantity and quality
of it- coal, portion- of the Laramie of western < 'olorado.

Mr. .1. B. Tybrkll: We find what we have called the Laramie and have corre-
lated with the Fort Union group, lying directly on the Pox Hill- beds', the bed.- from
which the plants are largely obtained. I have collected large number- of them my-
-.■If. Between those plant bed- and the typical Fox Hills bed- there is a series, lying
perfectly conformable to both, of white -and- and days that hold the most of our
western coal deposits, and which have been discriminated in the reports of the Geo-
logical Survey of Canada. The three -ere- in Canada an- perfectly conformable.
There i- no break whatever between the Colorado group and the top of the Laramie,

and tlnre i- a thickne-- of live tosix thoii-and feet to tin- top of the Fort Union group

with no break at all in -upetpo-ith.n ; there ha- 1 n a regular Bequence from the

bottom to the top. So if tic Laramie oomea in anywhere it mu-t conn- in at the
bottom, and it app'-ar- to me that it mu-l uome in there and not in tin- upper bed.-.

J. S. NEWBERRY — THE LARAMIE GROUP. 529

We cannot clearly recognize the American divisions ; but if the top of our beds repre-
sents the Fort Union, the Fort Pierre beds are six hundred feet below. I suppose,
then, that we would have to regard the intermediate shales and sandstones as Laramie,
though there is little to show why they should be separated from the Fort Union
group above.

Professor Lester F. Ward : I take it that the discussion here to-day should avoid,
so far as possible, repetition of the statements that have already been published. Like
Dr. Newberry, I have in my hands a large amount of material both from the
typical Laramie group and from the Fort Union group, which has not been published.
A few years ago, as you all probably know, I did publish a paper on the Laramie
group, to which I prefixed a prefatory discussion in regard to the probable age of
that group. In that discussion I admitted that there was the same lack of identity
between the Fort Union fossil plants and those of the lower Laramie which Dr. New-
berry has pointed out. In further investigations of this material (for at that time I
had only studied a small portion of it, except in a very general way) I have not had
any occasion to alter my opinion in that respect, and I am to-day prepared to say
what I said then and what Dr. Newberry has said this morning, viz., that so far as
the floras of the Fort Union group and of that which was originally called the Lara-
mie beds of Colorado, Wyoming, and New Mexico are concerned, they are not identi-
cal— the^y are very different.

I hazarded a possible explanation in case the geologists and animal paleontologists
eventually establish the synchrony of those beds, viz., that possibly the latitude taken
in connection with a different topography such as may have existed in the two regions
might account for the great difference in the floras. But I alsc expressed the opinion
that in all probability there would eventually be found a difference of age — how great
it would be premature for me to say. The great difference is not so much in the species
as in the general facies of the two floras. There are eight or ten identical species* in
the Laramie and Fort Union, but these weigh very little in comparison with the more
important fact that in the lower Laramie — the original Laramie formation — there is
a large predominance of such genera as Ficus, and also many palms, which, to the
mind of a paleobotanist naturally and probably correctly suggests a warmer climate.

Whatever may be true in regard to the difference of age — and it seems to me that the
two must go together — I am quite satisfied that a warmer climate prevailed during the
period of the deposition of the Wyoming and Colorado beds than that which prevailed
during the deposition of the Fort Union beds. Among the leading genera of the upper
beds are Populus and Platanus. Some of these forms are, I admit, very irregular and
peculiar, but they are not found in any such abundance in the lower beds. They are
more northern forms — forms which now, at least, grow in the colder climates, and
very few species of Ficus, very few genera of palms, are found, so far as my own col-
lection is concerned, in the Fort Union beds. Moreover, as Dr. Newberry has stated,

*The species common to the Laramie of Colorado and Wyoming and the Fort Union group, as
shown in the table of distribution given in my Synopsis of the Flora of the Laramie Group (Sixth
Annual Report U. S. Geol. Survey, 1885, pp. 443-514), are as follows :

Sequoia langsdorfli,

Sabal eampbellii,

Quercus olafseni,

Juglans rhamnoides,

Juglans rugosa,

Ficus tilicefolia,

Magnolia hilgardiana,

Trapa microphylla.
These are exclusive of several species thus far only found in the Laramie of British Columbia
and one of the American areas, as also of a number of more or less doubtful cases.

530 PROCEEDINGS OF NEW YORK MEETING.

there are forme in the Port Union which have an exceedingly recenl fades, but 1 am
very loath to argue from this a Tertiary age, For instance, there are what seem to be
the leaves of the identical Bpecies of hazel which grows now in the eastern parts of the
United States : yet I hesitate to argue from this thai the formation is necessarily very
nt.

In fact, the material from the Port Union formation which is .-till in my hands
(partly for the reason that I was unable to identify it with the published flora of the

globe, and partly because 1 was unable to publish more at that time) inclines to be-

> i < ■ \- • • that there would really be, as I then stated, no inconsistency in assigning to the

Porl I rnion an age as ancient as the closing period of the < !reta< us system. Some of

the farts I might enumerate here, but this would 1"' perhaps tedious; but Borne of the
forms ar irtainly not to be identified with any ofthe genera thai have • n found in the

-il i>r the living Btate. Such form- cannot be regarded as having geological import-
ance in fixing age, yet they go a long way in the direction of Bhowing us that the age

may be more ancient than has been supposed. Tin; genus Trapa has 1 n found in

both groups, but I am not thoroughly satisfied that the Bpecies are identical. Ln my
anxiety not to multiply Bpecies, I called it by the name given to the form described
by Lesquereux from the Point of Rocks beds, though it may prove to be a distinct
Bpecies; yet we may never know, from the fact that the material collected by him
was inadequate. 1 have collected from the Fort Union bed- specimens of that plant
containing entire rosettes of leaves as the}' would lie on the surface of the water, and
Bhowing to my mind that it must have belonged to the genus Trapa or a closely re-
lated form. The Point of Rocks material contained nothing but isolated leaves — that
i- to say. there were no rosettes and there were qo stem imply the form and ner-
vation of the leave-. These point to the gen us Trapa, and the probability is that they
belong to that genus.

The evidence afforded by the beds at Black Butte station, where the great saurian was
discovered by Professor Cope, is perfectly conclusive of the identity of the age of the
beds from which that fossil was taken withthatfrom which the leaves of that particular

locality were taken. We have at the .National Mu-eiim a Bpecimen of the hone from

that creature, adhering to the opposite Bide of which is one of the characteristic

Laramie leave-. I have been on this Spot, and collected other fossil plants from the

same immediate locality.

Now, with regard to the error, if error there be, in harmonizing or identifying the
Laramie and Fort Union deposits : I suppose the responsibility for this must largely
resl upon Dr. White, who has made a very thorough and exhaustive study of the
entire region, as he define- it from the standpoint of it- molluacan fauna ; and il Beems
to me that hi- identification of the two group- and I have conversed with him very

freely and very much upon this Bubject, and what I -ay is from memory of the oral

statements made by him— was in th.' nature of a broad, geological generalization. He,
in hi- extensive labors in that field, .-imply came upon the salient fact, that through-
out tic larger part ■■( t he region now occupied by the Rocky M> tains there i- abund-
ant evidence that there existed at a remote period, somewhere near the closeofthe
I or beginning of the Tertiary period, a great land-locked sea, originally

aewhat salt, later brackish, and Anally nearly fresh ; and that the deposits which
were made at tic bottom ofthe -, a are apparently continuous all the way up from the
pure marine deposits of the upper Ko\ Hills group to the highest of the Fort Union
deposits ; and be even ventures to say he has traced it in -one- places -till higher into

• la which arc admitted to !»• Tertiary.

J. S. NEWBERRY — THE LARAMIE GROUP. 531

I have one fact of my own observations which may be worth stating and which
may not be known to all. About 15 miles above the town of Glendive, on the right
bank of the lower Yellowstone river, there is a cliff, known as Iron bluff, which is
colored very bright red from having the carbonaceous matter burned out, and which
is full of fossil plants. It is also full of the characteristic Laramie shells, such as Dr.
White has described and has daily met with throughout the Laramie series. These
shells, he informs me, are identical all the way through the Laramie from bottom to
top. There is nothing to indicate that there is any difference in the age, so far as the
indication from the shells is concerned. This bluff is right on the bank of the Yellow-
stone river, and the railroad cuts through it, which makes the cliff there conspicuous.
Immediately below there is a short anticline, apparently a little island about a mile
in extent, filled with characteristic Fox Hills Cretaceous fossils. I have been on the
ground and collected large numbers of them, and everywhere we meet with them:
the wheels of the wagon as one drives over them crush the shells, so abundant are
thejr ; and there is no doubt that this is a typical Fox Hills bed, in Dr. White's un-
derstanding of the term "Fox Hills." Now, so far as I can tell, and so far as he
could tell from a careful study of the ground, this Iron bluff deposit — this Laramie or
Fort Union leaf-bed — rests directly and immediately upon the Fox Hills bed. If
there is any difference of age there is no indication at that point that it has been want-
ing from lack of conformity or from any other cause ; and it is certainly a very natural
conclusion that when one deposit rests conformably upon another at one point, and
when at another point two formations, the lower one being the same as in the first
case, have the same order and arrangement, the age of the overlying beds in both
regions is the same. That seems to be as clear a case of geological reasoning as we
have.

I observe that our friends across the border, of whom we have representatives here,
are still using the term Laramie for this formation. It seems to me that the bulk of
their Laramie is nothing more nor less than our Fort Union, and they seem to be some-
what in doubt (at least so I learn from reading a paper which reached me only a day
or two before I left Washington, with a Christmas greeting from Sir William Daw-
son) ; and I do not know but that we might as well settle the question in the way he
has settled it in that paper as in any other way. He simply says that the time may
yet come when, in fixing our arbitrary position for the line between the Cretaceous
and the Tertiary, we may be obliged to draw it through that continuous deposit which
we call the Laramie group.

Dr. Newberry's memory is entirely at fault when he says that in my " Synopsis "
I called the Laramie and Fort Union group Tertiary. I have been criticised for
arguing that they are Cretaceous. As a matter of fact I did not call them the one or
the other or argue for either view. I first gave a perfectly unbiased review of opinion
in which the advocates of each view were allowed to state their case in their own
words. I then did what had never before been done. I presented the evidence from
the fossil plants upon both sides in tabular form, getting together for the first time a
fairly complete list of all the upper Cretaceous species the existence of which had gen-
erally been ignored in the discussion of the question. These as well as the Eocene
species of all parts of the world were directly compared with the Laramie species.
The very careful analysis of this table which I made showed that the Laramie flora
occupies an intermediate place between that of the upper Cretaceous (above the Da-
kota group and Cenomanian) and that of the Eocene. The only conclusion I drew,

532 PROCEEDINGS OF NKW YORK MEETING.

if conclusion it can be called, was thai the whole discussion was a war of words, often
unworthy of the talent thai bad been expended upon it.

Prol r J. J. Stevenson : I should like to say a word or two about the section

that I>r. Newberry ha- put <>n 1 1 1 < - board. The statement that the Colorado group
cannot be differentiated in Colorado is not altogether correct. It is true that in a
considerable area beyond the Arkansas range it is a very difficult thing indeed to
differentiate the Colorado group ; but along the plain in front of the Rocky Mount-
ains in Colorado and New Mexico there is not the slightesl difficulty in recognizing
tin' Fort Benton as a mass of Mack shale ; the Niobrara above that, gray to blue lime-
stones separated by black shale; then the Fori Pierre, drab to yellow sandy shales,
containing nodules of limestone and iron ore, while above that and quite easily Bep-
arable from it we tind in northern and central Colorado the Fox Hills group. This

is the Cretan us along the waters of the South Platte, where the Pox Hills ^roup is

characterized all the way. from the bottom to the top, by a nodose fucoid, Halym

- major, which was al one time a very interesting topic of discussion. The Fox
Hills group in central Colorado is upwards of one thousand feet thick, consisting
mostly of sandstones, some of them calcareous and rich in Fox Hills fossils, with some
bed- of coal, which have been opened in the neighborhood of Greeley. At Canon < !ity,
('•dorado, the Fox Hills group is only about 350 feet thick, that being the vertical
extent of the Halymenites. In that interval are the important coal beds and numerous
sandstones or -bales containing plants which doubtless answer to those of the plant
bed which I found on one occasion near Evans, on the South Platte, but which I
could never tind again. Further southward, near Trinidad. Colorado, the Fo\ Hills
i- only v" feet thick, thai being the vertical range of the Halymenites. In thai field,
however, the Pox Hill- has been included in the Laramie; but the Laramie group
above the great coal-bearing series is easily separable from this Halymenites sandstone.
Southward, in New Mexico, the Halymenites or Fox Hills sand-tone entirely disap-
pears.

The point I wish to make is that the upper Missouri section of the Cretaceous is
distinctly recognizable as far south as central Colorado. Beyond that southward
the Fox Hills thins out until it disappears in New Mexico, but the other members of
the section can be recognized without any difficulty in front of the Rocky Mountains
and around their southern end to the Rio Grande.

Professor E. I> Cope: Ii seems to 1 me more complicated the more we investi-
gate, and a greater number of problems arise to be Bolved. What Professor Steven-
Bon has ju-t given is established. I can demonstrate from my own observation what
Dr. Hay den has Btated— that i.-. the conformity of the four or five gradations with
the Laramie above. There seems to be absolutely no disturbai r want of con-
formity in the upper Missouri between those three horizons. 1 could gel the Pierre
I- in the bottom oi the bluff and Pox Hills in the middle and Laramie at the top.
On the question of the Laramie's position in the Cretaceous or Tertiary series the

vertebrate fossils throw some light. The reptiles and -an rain- are Cretan u<. I have

discovered in New Mexico the Puerco series jusl above the Laramie, and in thai 1

have about a hundred -| ies of the mammalia. I have also discovered mammalia

in the Laramie. Professor Marsh has added some species to those previously known.
Tic - are of identical character with the Puerco mammal-, although there i-

no species Identical with any in the Puerco, where there is not a Bingle Cretace
reptile. The mammals of the Laramie are. like the saurians, rather Cretaceous than
Tertiary : but the character is nol »o pronounced.

G. H. WILLIAMS THE SYRACUSE SERPENTINE. 533

The next paper read was on—

OROGRAPHIC MOVEMENTS IN THE ROCKY MOUNTAINS.

BY S. F. EMMONS.

The paper was briefly discussed by J. S. Newberry and J. W. Spencer.
It is published in full among the memoirs, forming pages 245-286 of this
volume.

The next communication was the following :

NOTE ON THE ERUPTIVE ORIGIN OF THE SYRACUSE SERPENTINE.

BY GEORGE H. WILLIAMS.

The undisturbed Paleozoic strata of New York state are so noticeably free from
intrusions of igneous rocks that any occurrence whose eruptive nature can be estab-
lished possesses an unusual interest. Such an occurrence is the serpentine of James
street hill, in Syracuse, the real nature and origin of which has only recently been
placed beyond all doubt by new exposures made in the course of street grading.

This rock has been known since 1837. It was described by Vanuxem and Beck in
the New York state reports, who regarded it as " metamorphic," but as probably not
produced by igneous action. Hunt bas lately brought the occurrence again into
prominence by citing it at great length in his "Mineral Physiology and Physiography "
as evidence for the origin of serpentine by chemical precipitation from aqueous
solutions.

The rapid growth of the city had apparently rendered the serpentine permanently
inaccessible when, in the winter of 188G-'7, the writer succeeded in obtaining for
study a considerable series of specimens preserved in old collections. The results
of this purely petrographical examination (communicated to the National Academy
of Sciences April 20th, 1887, and published in the American Journal of Science for
August of the same year) were (1) the identification of the Syracuse serpentine, in
spite of its advanced state of alteration, as a member of the rare peridotite type
kimberlite, similar to those described by Lewis from South Africa and by Diller from
Kentucky; and (2) adducing from the structure of the rock strong evidence of its
eruptive origin.

This evidence has been set forth at length in the above-mentioned paper, and need
not be again referred to here. The object of the present communication is to make
known certain new and unexpectedly acquired evidence, which places the igneous
origin of the Syracuse serpentine beyond a question.

Since 1887 the digging of a deep sewer on James street and the lowering of the
grade of Green street, about forty rods further south, have exposed two admirable sec-
tions through the serpentine, which disclosed its relations to the adjacent limestone
and at the same time yielded an abundance of material for further study. These ex-
posures established three distinct proofs of eruptive origin for the serpentine in addition
to the internal evidence already adduced from the structure of the rock itself. These
three proofs are as follows:

1. The mode of occurrence of the serpentine in the limestone. — This was distinctly
that of a dike, cutting perpendicularly across the nearly horizontal strata; forcing

LXXI— Rur.T,. Grot,. Soc. Am., Vol. 1, 188').

534 PROCEEDINGS OF NEW YORK MEETING.

its way in places between them : and, as Been in the exposure on Green street, con-
rably disturbing them in its immediate vicinity. Two section?, drawn with care
to b lai . Bbow the serpentine in a position in the limestone difficult, if n < > t

impossible, to account for except "n the hypothesis of eruptive < >i i<_ci n.

*_'. Inclusions brought <>/> by the intrusive rock from below. — Much of the serpentine
i- full of angular fragments of other rocks imbedded in it. Souk; poli.-hed specimens
hibited to the S< have al least one-third of their surface composed of auch
included fragments. The vast majority of these are composed of the adjacent lime-
stone, but others also occur. One specimen contains a large fragment of Mack shale
(probably (Jtica shale), which here is over 1,000 feet below tbe surface ; another speci-
men remains a fragment of an acid crystalline rock, granite or gneiss, which must
here lie over i'.iiiki i ". • < - 1 below the surface. Vanuxem mentions such granitic and
syenitic inclusions as not uncommon. They could not, however, have 1 ne im-
bedded in the serpentine except at a considerable depth, whence they were carried
upward by the molten rock.

3. 77.. onal alteration of angular limestone inclusions. — As has been already
mentioned and as is well shown by the specimens exhibited, the Syracuse serpentine
is frequently full of limestone fragments, which differ much in shape and size. All
of these included fragments show the effects of contact metamorphism through the
influence of heat, and the new minerals which are produced in this way have invari-
ably a /.onal arrangement parallel to the 6ides of the fragments. This i- a proof that
the metamorphism could only have been effected after the limestone had been broken
into its present shape and imbedded in the serpentine; hence the enclosing rock
must have been the agent of metamorphism.

In speaking of the eruptive origin of the Syracuse serpentine it is not, of course,
intended to imply that the original eruptive rock was itself serpentine. Serpentine,
as i- well known, is always an alteration producl of Boine otber rook — generally of a
feldspar, free basic eruptive, or peridotite. The Syracuse rock is not now by any
means all Berpentine, although a greater portion of it has been changed by hydration

into this mineral. Nevertheless, enough of tbe minerals and structure of tl riginal

rock -till remain to identify it with the particular type of peridotite known a- kim-
berlite.

There is another occurrence of serpentine, with mica crystals one-third of an inch
broad, mentioned by Vanuxem at a fault between the Calciferous and [Jtica, near
Maiilieim bridge, on East Canada creek, New York. It is associated with crystalline
carl onate of lime containing pyrite and blende

The President, Professor .1 .\ m es Ball: There is a dike of trap rock, also mentioned
by Vanuxem, cutting the Genes lates near Ludlowville, New York.f

\l .1 I' Ki.\ir: There are a number of such occurrences near [ibaca. There are
Btnall crack- in tbe Devonian -hale that very Btrongly resemble dike-. In these the
material seems to be -hale, ,md i- in such an advanced stage of alteration that it
readily effervesces with acid-. The rock i- at least extraordinary, containing as it
does abundant biotiie. It has a high specific gravity. The largest dike i- not more

than two or three inches wide' where it cut- the -hale.

.i Reports, Vol. I ll. 1842, p. 807.
i Ibid., i

REPORT OF THE COUNCIL. 535

The next paper was entitled —

NOTES ON THE SURFACE GEOLOGY OF ALASKA.
BY ISRAEL C. RUSSELL.

This communication was discussed by N. S. Shaler, T. C. Chamberlin, and
Mr. Russell. It is published, with the discussion, among the memoirs, form-
ing pages 99-162 and plate 2 of this volume.

At the close of the discussion the Society adjourned to meet in the same
place at 10 a. m., December 27.

Session of Friday, December 27.

The Society met at 10 a. m.; President Hall in the chair.
The report of the Council was read, as follows:

REPORT OF THE COUNCIL.

To the Fellows of the Geological Society of America.

The Executive Council preseut the following report:

The number of Fellows now on the roll is 173, three haviug died since the
last meeting of the Society. The canvass of ballots cast for Fellows shows
an addition of fifteen to the number; so that the Society will begin the new
year with a roll of 188 Fellows. The Treasurer reports a balance of $1,716
in the treasury.

After mature consideration, the Executive Council have determined upon
a plan of publication which differs not materially from that proposed in the
admirable report* of the advisory committee appointed at the Ithaca meet-
ing. For the present, there will be but one series, a large octavo, to be
known as the " Bulletin of the Geological Society of America." All ab-
stracts of papers with the accompanying discussions, as well as the briefer
papers, will be published in the Proceedings of the meetings ; the longer
papers and the discussions upon them will be published separately from the
Proceedings, but authors will not be required to receive the discussions with
their separates. A contract on favorable terms has been made with Messrs.
Judd & Detweiler, of Washington, D. C, for the publication of the ma-
terial already on hand, and the manuscript for the most part has gone for-
ward to the printers. Publication will be pushed promptly from this time,
as all preliminary matters have been settled.

The whole matter of publication has been placed under the control of the
Executive Council ; but the conditions should be well understood by Fellow-.
The income of the Society for 1890 is likely to be not far from $1,900.

* Copies of this report were distributed at the Toronto meeting.

.").;<; PROCEEDINGS OF NEW fOBE MEETING.

The expenses of administration will probably be aboul the 8ame as in 1889 ;
the Bulletin will average, with cost of covers and of distribution, somewhat
more than $2.00 :i page for the edition of 500 copies; there is every reason
to look for almost 600 pages of text. The margin, therefore, is uot more
than $400. This admits of but limited expenditures for maps, cuts, and
plates. It is evident that the Fellows must exerl themselves to place the
publications on a Bure basis by securing a fund for defraying cost <>f pro]" c
illustrations.

The presentation of estimates of expenditure for the year 1890 cannot be
made satisfactorily, as the Society has only begun its effective work: lmt
there is necessity that authority for expenditures in publication he given to
the Executive Council at this meeting. The estimate for printing the Bul-
letin is based on the agreement with Messrs. Judd & Detweiler, according
to which the cost of the Bulletin, including paper and everything else, ex-
cepting the covers ami binding, will be $1.90 per long primer page and S'J.'JO
per brevier page, the former being used for memoirs and the latter for other
matter. The expenses of the Secretary for postage, stationary, and printing
will probably fall below those for 1889.

The canvass of the ballots received by the Secretary shows that the Con-
stitution recommended by the Committee appointed at the Ithaca meeting
has received the requisite three-fourths vote in favor of its adoption, bo that
that Constitution, with the accompanying By-Laws, will go into effect im-
mediately upon the final adjournment of this meeting.

The oew Constitution provides that vacancies arising shall be filled by
the Council ad interim. This involve- the selection of three additional
Councilors, and also, if the Council think it necessary, an Editor. The
( louncil is of the opinion that the selection of an Editor is indispensable.

The Executive Council cannot refrain from congratulating the Society
upon the auspicious close of the first year. There have been manifested on
all aides a sacrifice of personal feeling, a readiness to yield cherished opin-
ions respecting methods, a freedom from self-assertion, and an earnest deter-
mination to make the Society succeed which could have been expected
hardly by the most sanguine, and which augur well for the future of the
5 iciety.

The Executive ( ' >uncil presenl the following recommendations :

1. Thai the Treasurer be authorized to pay all bills for publication of the
Bulletin, when they have been certified by the officers chosen by the Council.

•_'. That immediate efforts be made to secure a Publication Fund of $10,000,
to provide an income to pay for map-, plate-, and other illustrations such as
ordinarily cai t be paid for by the Society.

:;. That the Treasurer, with advice of the Council, be authorized to invest
;1- the first part of the Publication Fund $1,000 of the money now in the
Tr< asury.

W. B. CLARK — TERTIARY OF CAPE FEAE RIVER. 537

4. That the Council be authorized to prepare a list of exchanges, not to
exceed 75 in number.

5. That the Fellows pay strict attention to the section of the By-Laws
providing for commutation of annual dues by a single prepayment of $100.

The recommendations of the report were adopted by vote of the Society.

The President then delivered an address on the early history of American
geology and geologists, for which the Society, on motion of J. D. Dana,
voted its thanks. Professor Dana followed with a few additional statements.

The first paper of the session was —

ORIGIN OF THE ROCK PRESSURE OF NATURAL GAS IN THE TRENTON
LIMESTONE OF OHIO AND INDIANA.

BY EDWARD ORTON.

The paper was discussed by I. C. White, A. C. Lawson, W J McGee, and
Professor Orton. It is published in full among the memoirs, pages 87-98.
The next paper was —

ON THE TERTIARY DEPOSITS OF THE CAPE FEAR RIVER REGION.

BY WILLIAM B. CLARK.

There is perhaps no portion of our country where the relations of the deposits are
less clearly comprehended than in the Coastal Plain bordering the Atlantic. This
region varies in width from a few miles in the north to more than one hundred and
fifty miles in Georgia, and covers the eastern portions of New Jersey, Delaware, Mary-
land, Virginia, the Carolinas, and Georgia, together with all of Florida. Bounded
upon the west by the hilly country of the Piedmont Plateau, it stretches away to the
coast, an almost level area, except where broken by the meandering rivers and their
tributaries, that have as yet but just entered upon their work of denudation.

To the various formations found represented within this region geologists have
applied the taxonomic terms Cretaceous, Eocene, Miocene, etc., although from the
meager study of the fossiliferous deposits that has hitherto been made we are by no
means certain that these terms can be used with propriety. It is not the intention in
this paper, however, to discuss this aspect of the subject, important as it is, for that
can best follow a detailed examination of the stratigraphy and paleontology of the
entire area.

The Cape Fear river region presents some of the most puzzling problems in the
geology of the Coastal Plain. The formations here represented have been often re-
ferred to in geological literature, and quite different opinions held as to their correla-
tion. In its topography the Cape Fear river region partakes of the general character
of the Coastal Plain, which limits the study of the pre-Quaternary strata mainly to
the river banks and accidental excavations.

There has apparently been little difference of opinion as to the taxonomic position
of the greensand marl, that is widely characterized by the accepted Cretaceous fossil

538 PROCEEDINGS OF NEW YORK MEETING.

Exogyra costata. Starting with this horizon, which forms the base of the series in
the lower Cape Fear river region and is the most extensively represented <>t' any of
the fossiliferous deposits, we find that in several localities it is overlain by a light-
colored calcareous marl, that in the neighborhood of Wilmington occurs as a compact,
fine-grained limestone or as a firmly cemented calcareous conglomerate. A.n exami-
nation of the region shows that this marl occupies wide basins or hollows within the
Cretaceous. It may be considered as Eocene. It- paleontologicul characteristics will
be referred to later. Widely extended over Eocene and Cretaceous alike is an inco-
herent >hell marl that may be referred to the Miocene. This, in brief, is the order of
Buperpositi >f the several formations with which we have to deal.

These pediments probably represent a succession of events somewhat a« follows : At
the close of the Cretaceous period, the deposits that had been accumulated were ele-
vated above the sea for a sufficient length of time to allow the meandering streams
from the mountainous regions to the west, together with local tributaries, to excavate
-hallow basins. It is, moreover, evident that this process could not have been con-
tinued sufficient!}' long to plane off or base-level the region, else the depressions
themselves would have disappeared. When this land surface became depressed below
the sea, the deposits of the Eocene, formed largely from the remains of marine animal-.
were strewn over an uneven sea-floor. When elevation had brought them above the
level of the sea, denudation again began, bearing away the materials accumulated.
The elevation could not have been great, hut erosion on the other hand was long con-
tinued, until the surface of the region was approximately base-leveled. In this plan-
ing down of the land, the higher ridges of the Cretaceous were likewise removed, so
that an almost level sea-floor was this time presented for the reception of the sands
and shells of marine organisms which form the next formation, recognized as Miocene.

A geological map of the Cape Fear river basin would exhibit the Eocene in numer-
ous detached areas, while the Miocene would be found in long hand- along the water-
courses, an arrangement of the deposits that would be anticipated after they had passed
through the various cycles of change above recorded.

That these various formation- present pal itological peculiarities was early per-
ceived. From the fact that the limestone afforded fossils which were recognized as
in part of Cretaceous age, it was referred to the upper Cretaceous, or by others held
e transitional in character between the Cretaceous and Eocene.

Lyell * stated in a communication to the Geological Society of London, made in
1842, that one of his chief reasons for examining the geology of the southern Atlantic
states was "to a -certain whether any rocks containing fossils of a character interme-
diate between those of the Cretaceous and Eocene really exist." The result was that

he found •• n condary fossils in those beds which have been called upper Secondary

and supposed to constitute a link between the Cretaceous and Tertiary formations."
Lyell collected from the lime-tone at Wilmington and Rocky Point, the localities
most carefully examined by the writer. Although the facts presented may not affect
I, veil- general conclusions, yet the occurrence of characteristic Cretaceous fossils at
the same horizon with Eocene i- beyond dispute.

Tuomey stated before the American Association for the Advancement of Science

in l-i- that " well characterized Cretai us forms " occur at Wilmington in the

.-a me beds with ■ .it are "considered characteristic of i he Eocene of the United

• Pi ..f i ondon, rol. ::. 1842, p 7

'roe, \ne-i a- \i . s,-i , v.t i, im-

W. B. CLARK TERTIARY OF CAPE FEAR RIVER. 539

States." A list of species is added. In a later publication* the same position is
taken, though explained on the ground of contemporaneous existence.

Conrad stated in 1865, concerning this locality, that " Eocene and Cretaceous fossils
are there mingled in a breccia, "f and later that " the mixture of Secondary and Ter-
tiary fossils in this breccia shows that a disturbance occurred in the bed of the Eocene
ocean, which evidently, from Tuomey's account, extended into South Carolina."
Conrad cited several instances in which Deshayes and others have shown similar oc-
currences in European strata ; and although he did not enter more in detail into a de-
scription of the Wilmington locality, yet his opinion as to the commingling of Eocene
and Cretaceous forms is clearly stated.

By a comparison of the specimens with well-known forms from Claiborne and
other Eocene localities, the following species have have been identified : —

Aturia alabamiensis, Conrad,
Pseiidoliva vetusta, Conrad,
Oliva alabamiensis, Conrad,
Conus gyratus, Conrad,
Emarginula eversa, Conrad,
Trochita trochiformis, Conrad,
Siliqicaria vitis, Conrad,
Pecten membraiiosus, Morton,
Terebratidina lacryma, Morton,
Lunulites distans, Lonsdale,
Mor Ionia pileus-sinensis, Ravenel,
Sismondia plana, Conrad ;

besides others of Eocene aspect, but of whose specific determination there is some
doubt.

At the saijie time numerous Cretaceous fossils occur; as —

Bactdites compressus, Say,
Nautilus dekayi, Morton,
Navicula uniopsis, Conrad,
Venilia. conradi (?), Morton,
Cardium spillmani, Conrad,
Cucidlcea antrosa, Morton,
Gyrodes abyssimus, Conrad,
Zenophora leprosus, Morton ;

enough certainly to clearly indicate the presence of a Cretaceous fauna in a great
variety of forms. It is less probable that these different species had a contempora-
neous existence than that a mechanical commingling of the various forms took place
during the deposition of Eocene sediments. With few exceptions, the specimens are
casts ; but, as both those from the Cretaceous and Eocene present similar states of
preservation, it is probable that at the time the commingling took place the shells
were still intact, and that subsequently they have both passed along similar lines of
change.

Another interesting occurrence of a like nature is the presence of E.rogyra cosUitu

*Proc. Acad. Nat, Sei., Philadelphia, vol. 0, 1852, p. 193.
fProc. Acad. Nat. Sci., Philadelphia, vol. 17, 1805, p. 72.

540 PROCEEDINGS OF NEW YORK MEETING.

in Miocene strata surrounded by numerous characteristic Miocene fossils. This was
referred to by Emmons in 1868.*

Bucb comminglings of different faunas are not unknown in other regions and from
other formations; but the writer knows of m> instance where the occurrence is so
marked or wbere, from the great number of fossils, the evidence is so undoubted.

The Cape Pear river region presents many other problems of geological interest that
require more extended Btudy before judgment can be passed upon them. These, to-
gether with other questions connected with the early Tertiary of the Coastal Plain, the
writer is now engaged in investigating.

The next paper read was entitled —

NOTE OH THE PRE-PALEOZOIC SURFACE <>K THE Ai:< III AN TERRANES OF

C LNADA.

I'.V ANDREW C. I.AWsov.

The paper was discussed by J. W. Spencer. It is published among the
memoirs, formiDg pages 163—174.

The nexl paper on the programme was —

BTRUCTURE AND ORIGIN OF GLACIAL BAND PLAINS.

li V WILLIAM MOKIUS DAVIS.

It was read by title, the author yielding his time in order that there might
be more time for discussion. This paper is published among the memoirs,
pages L95-202, plate 3.

The Society then took a short recess.

Alter recess, Vice-President A. Winchell occupied the chair. In the
absence of the author, Mr. J. 1>. Tyrrell read the following paper:

GLACIAL FEATURES O] PARTS OF THE YUKON A.ND MACKENZIE BASINS.

KV K. (i. Me. (>N\ KM.

The following note-, which I have endeavored to make as brief as possible, on the
more salient glacial features of part- of the Yukon and Mackenzie basins, were ob-
tained while on a hasty geological reconnaissance in the north in the summers of i^sT
and i-1-- The route travelled on this occasion followed the main water-courses of
the country. Starting from the mouth of Dease river, west of the Rocky Mountain-.

in hit. 60 N the Liard was followed in iU stormy cour astward through the

i: • ke - to its junction with the Mackenzie in the low lands east of this range. Prom
• Simpson, at the mouth of the Liard, I ascended the Mackenzie and it* continua-
tion, Slave river, to I Smith, and then, turning northward, descended Slave river

logy of North Carollnn by E. Bmmnnn,

R. G. MCCONNELL — THE YUKON AND MACKENZIE BASINS. 541

to Great Slave lake, coasted along this lake to its outlet, and then descended the
Mackenzie river through its whole length to the head of its delta at the mouth of
Peel river, lat. G7° 45' N. From this point the Rocky Mountains, here ahout four
thousand feet in height, were recrossed by the Peel river portage to the head waters
of the Porcupine, and the latter followed westward, through its long ramparts, to
its junction with the Yukon. Then bending again to the south, the Yukon was as-
cended to old Fort Selkirk, where connection was made with the line of exploration
traversed in the previous summer by Dr. G. M. Dawson. Of the rivers mentioned,
the Makcenzie only had been previously examined by a geologist, and that only in
a cursory manner and before the subject of glaciation had received much attention.

"We shall commence the descriptive journey at Great Slave lake. This lake is sit-
uated upon the western margin of the Archean axis, and had originally the form of
a great cross, with one arm penetrating the crystalline schists, while two others
stretched north and south along the junction of these with the newer sedimentaries,
and the fourth extended itself over the flat-lying Devonian to the west. The southern
arm has now completely disappeared, and its bed is filled with a great alluvial deposit
of clays, false-bedded sands, and fine gravels, which have been brought down by
Slave river and through which its tortuous channel now winds. Not satisfied with
burying the southern arm, this river is now pushing its delta far out to sea, and
threatens at no distant day to inflict a similar fate on the whole eastern portion of the
lake. The time spent on Great Slave lake was not sufficient to enable me to form a
theory as to its origin which would have much value, but its peculiar shape, the
great depth of the Archean portion taken in connection with the comparatively low
elevation of the country which surrounds it, and the precipitous cliffs which border
the shores of this part in so many places, seem inexplicable by glacial agencies. It is
possible, however, that the western portion, which is much shallower and has low.
shelving shores, may have been excavated in part or altogether by a glacier forcing
its way out of a previously formed basin to the east. No very distinct groovings or
stria? were observed around the lake, but the hummocks of the roches moutonnees
gneissic surface of the country in the vicinity of Fort Rae have their major axes gen-
erally orientated in a direction about S. 30° W., or diagonally across the great
northern arm of the lake on which the fort is situated. Well defined glacial hum-
mocks carved out of massive dolomites were observed in one place on the western ,
arm running in a westerly direction, or almost parallel to the general course "I this
portion of the lake.

Great Slave lake, like the other great lakes to the south lying along the Archean
boundary, affords proof in the terraces surrounding it of former higher levels of it-
waters. Fragments of two lines of terraces were noticed in a number of places
around the western arm of the lake. The greatest elevation of these did not, how-
ever, exceed 30 feet above the present surface of the water.

Hay river, which enters great Slave lake near its western end and drains the coun-
try to the southwest, has evidently had a history somewhat similar to that of the
Niagara; but it has not vet been thoroughly explored. In its lower part its valley
is carved out of a soft shaly terrane holding Hamilton fossils. Fifty miles above its
mouth a heavy band of cream-colored limestone overlying the shales crosses the river,
and a striking change is at once observed in the aspect of tin' valley. As we advance,
the valley contracts and becomes a gorge, so deep and narrow that its precipitous
walls, buttressed below by an embankment of fallen fragments, almost appear to over-
hang the stream, while the river, reduced in width in some parts to 100 feet, dashes

LXXII— Bull. CJeol. Soi . \m., Vot. 1,1889.

542 PROCEEDINGS OF NEW y<.|;k MEETING.

along it- bowlder-filled channel with bewildering impetuosity. At several points
small side streams fling themselves over the brow of the unworn cliff's and curve
gracefully down into 1 1 1 « - stream beneath. Six miles above it- mouth the gorge is
interrupted by a fall 50 feet in height, and a mile further up is closed completely by
a fall of 100 feet. A.bove the falls the river has failed to produce more than a feeble
impression on the hard limestone beds which floor the Burrounding country, and l<
it- valley almost altogether.

The Bay river falls owe their origin to precisely the same cause as that which pro-
due- the famous falls at Niagara, viz., the superposition of hard limeston > soft

shales, and the consequent undermining and destruction of the formeT effected by the
rapid erosion and removal of the supporting beds. It is interesting to And that the
rate of retrocession of the two Bills, measured by the length of their gorges, has been
almost precisely the same. The quantity of the work done by the two streams can-
not, however, be regarded as much more than a coincidence, as the factors in the two
as are entirely different. The volume of water which falls over the precipice at
N agara is ten-fold greater than that carried by Hay river, while it- erosive power is
relatively less on account of its greater purity. Besides Hay river, a number of
un- which join the .Mackenzie from the south and Bouthwest in the lir-t 100 miles
of it.- course are interrupted by falls and heavy rapid-, all of which probably date
from tic- glacial period.

Proceeding down the Mackenzie from Great Slave lake, alluvial clay- are noticed
for some miles, and then a bowlder clay, scarcely distinguishable in character from
the same formation as developed in eastern < lanada 3.000 miles distant, makes it- ap-
pearance. It occurs here as a light yellowish, compact, arenaceous clay filled with
rounded Archean bowlders and. as elsewhere, showing only faint signs of stratifica-
tion. It i- traceable in numerous exposures as far as the mouth of the Liard, which
joins the Mackenzie l">o miles from it- head.

The Liard which joins the Mackenzie from the west, affords an excellent cro — eotion
of the glacial beds covering the country between the latter river and the mountain-.
These do not, however, present much variety. Heavy sections of bowlder clay rest-
ing on the Devonian limestones occur along the valley for the first 50 miles, and then
sink beneath the Burface; and in the next reach of 60 or 60 miles the river winds

through oi f th filled up preglacial depressions which are bo frequently met with

..ii the area ..I' the Great Plains. In this the ordinary lake deposits only are seen.
West of this basin the Cretaceous Bhales, which have now replace, 1 the Devonian
li m. --lone-, rise to the Burface but arc cap pel with stratified Bhales, sands, and gra\ els
only, the bowlder clay having disappeared. Glacial erratics, on the other hand, ex-
tend far beyond the limits of the bowlder clay itself, and are found in Bome abundance
as far weal as the eastern edge of the plateau country, which in this latitude borders
the foothills of the Rocky Mountain-. They were also found on the flanks of a
in, .in, tain- ituated opposite Port Liard, in lat. 60° 15' N\, long. 128 \\'.. at a height

of 1 ,600 feet above the Burfai f the surrounding country, or about 2,800 feet above

the

> the Mackenzie and continuing on our way down it. we find bowlder

claj on the surfa f the rocks and tilline; up irregularities in tl Id preglacial

-,!,■ ir north as the head of its delta in latitude 67 I / N , and this notwith-

nding the fact that lesi than 1 < m > miles below the mouth of the Liard the Mackenzie

enters the fl ol the Rocky Mountains; and for the next 600 or 600 miles

partially guarded on tl aat by ranges of mountain-, Borne of which ex-

R. G. MCCONNElL — THE YUKON AND MACKENZIE BASINS. 543

ceed 4,000 feet in height. The howlder clay or till of the Mackenzie valley, although
mostly of the ordinary type, presents some variations. For many miles above Bear
river it is exceedingly dark in color and, with the exception of one layer at its base,
is almost destitute of bowlders. It has a thickness here of over 250 feet. In other
places it exhibits an imperfect stratification, and it frequently holds irregular shaped
inclusions of a lead-gray clay, some of which are distinctly bedded.

The only evidence of an interglacial period observed was the discovery in one place
of an intercalation of stratified sands and gravels dividing the bowlder clay into
upper and lower parts. This might, however, be due to a purely local cause.

The bowlder clay throughout the greater part of the valley is overlain by heavy
deposits of stratified sands, clays, and gravels, and is underlain by a gravel formation
somewhat similar to that which occurs in the same relative position on the plains of
Alberta and Assiniboia, and which I have elsewhere called the Saskatchewan gravels ;
from which, however, it differs in containing a larger proportion of Laurentian pebbles.

The few facts observed in regard to the direction of the ice flow in the Mackenzie
valley support the theory of Dr. Dawson as to its northerly movement. In the west-
ern part of Great Slave lake the direction of the ice current, as previously stated, was
due west. Five degrees further north, well marked glacial striae trending N. 15° W.
were found crossing the summit of Roche Carcajou. This rock, which must have
been completely submerged, rises to a height of 1,000 feet above the surface of the
river. Important evidence on the same point is also afforded by the fact that the
till near the lower ramparts of the Mackenzie is in approximately the same latitude
as the northern boundary of the Archean area to the east, and the gneissic bowlders
which it contains must have travelled either directly west or northwest in order to
reach their present situation.

The facts adduced above allow the inference that the ice from the Archean gathering
grounds to the east poured westward through the gaps and passes in the eastern flank-
ing ranges of the Rocky Mountains until it reached the barrier formed by the main
axial range, when, being unable to pass this, it was deflected to the northwest in a
stream from 1,500 to 2,000 feet deep down the valley of the Mackenzie and thence
out to sea.

Leaving the Mackenzie for the Yukon, we climb and cross over a couple of ter-
races, the higher of which has an elevation of 500 feet above the river or about 000
feet above the sea, and then on this route leave all traces of the glacial age behind,
although a few miles further north erratics are found fully 1,000 feet higher. In
descending the mountains on the west we follow a branch of Rat river through a
wild canon cut out of flat-lying sandstones and quartzites, from the mouth of which
a level terrace, with fragments of a higher one resting on it in places, stretches west
to Rat river. These terraces are much higher than those on the eastern side, and
have an elevation of 1,500 to 1,700 feet above the sea. Proceeding down Rat river
to the Porcupine, and down the latter through its ramparts, sands, gravels, and silts
are found resting on the country rocks, but no bowlder clay nor glacial erratics were
anywhere seen. Some distance below the ramparts the vallej of tin' Porcupine
widens, and from that on to its mouth it serpentines through a low alluvial plain ele-
vated only a few feet above the surface of the river and evidently representing a
iilled-up lake basin or former wide dilatation of the river channel. Turning up the
Yukon from the mouth of the Porcupine, this river splits up into innumerable chan-
nels and, spreading out in places to a width of eight or ten miles, cuts for 75 miles
through the same alluvial formation. Above this the valley becomes more contracted,

•"11 PROCEEDINGS "I SEW Y<>UK MEETING.

and occasionally, for the next 200 miles, sands, silts, and gravels Bimilar to those on the

Porcupine il ■ it- bottom. Approaching 1 1 1 « • Stewart river, wide gravel terraces from

30 i" LOO feet high border the river and recur at intervals all the way t" i bo Kink rapids
on Lewes river, below which point the bowlder clay, which has nol been seen since
leaving the Mackenzie, again makes it- appearance. Above this, ice groovings and
ings and all the other well-known marks of glaciation are everywhere evident.
I had m> opportunity of examining the plateau bordering the Yukon; but, judging
simply from the records of the ice age which the valley itself affords, it would appear
that the glacier which undoubtedly tilled the upper part of the valley of the Lewes
and moved northwards did n>>t descend below a point aboul 50 miles above the mouth
of the Pelly, or lat. 62° 50' N. Below this the deposits indicate a flooded valley, but
nothing else.

B ore closing this paper ] should like to draw attention to a fact which may have
some bearing on the non-glaciated condition of p;irt of Alaska and the adjacent por-
tion of the North West territory of Canada, viz., that glaciers are unknown in the
Rocky Mountains north of the headwater- of the Athabasca, or about lat. 54° 2T.
North of this occasional patches of snow survive the summer in sheltered tmuks, hut
even these decrease in frequency with increasing latitude : and on the Peel river port-
age, in lat. »'»7 30' X.. the snow bad entirely disappeared hct'.ire the middle of July.
.\ -•.. in descending the Porcupine and ascending the Yukon, no snow was Been until
far up the Lewes, and no glaciers until the head water- of this stream were reached.
It follows from this that climatic changes which would extend the present glaciers
of the Bow and Saskatchewan far down their valley- might have little or no effect in
imposing glacial conditions on this more northern region.

Geologk \i. Survey <>r Canada, December 24, 1889.

The reading of tl.i- paper led t<> a continuation of the discussion on Alaska,
in which Alexander Winchell, W. M. Davis, I. < '. Russell, J. \V. Spencer,
ami ( l. K. ( rilberi participated.

The next paper was entitled —

POST-TERTIARY DEPOSITS OP MANITOB \ Wh I'll I. \ I >.l< >l \ I \< I TERRITOR1 E8

OF NORTHWESTERN CANADA.

r.V .i. B. TYRRELL.

This communication was discussed by J. E. Mills, T. C. Chamberlin, N.
3. Shaler, W J McGee, J. W. Spencer, and Mr. Tyrrell. It is published
among the memoirs, forming pagi - 395 11" of this vol e.

The substance of the next paper, read by Professor C. H. Hitchcock in
the absence of the author, is contained in the following abstract :

\ MOB LINE OF Rl I RO< E88IOU I \ ONTA RIO.

\;\ i;i.\ . Q. i ■KK.hK.KH K WEIGHT,

[ Abstract \

This paper is principally occupied with the results of an investigation as t" the
character of the Oak Knolls in Whitchurch and King townships, York county, On-

C. F. WRIGHT — A MORAINE OF RETROCESSION. 545

tario. Oak Knolls is the name of a part of the continuous ridge separating Lake
Ontario from Lake Huron. The height of this ridge above tide does not vary much
from one thousand feet, as shown by the railway elevations. At King station, on the
Northern railway, the elevation is 955 ; but this is not the highest point of the road,
and the glacial summits rise on either side considerably higher. At Goodwood, on
the Midland division of the Grand Trunk, it is 1,090 feet. At Pontypool, on the
Canadian Pacific railway, fifty-two miles northeast of Toronto, the elevation is 1,064
feet. At Summit station, fourteen miles north of Port Hope, the elevation is 910
feet. Whether this is the highest point or not I do not know, nor have I the facts
concerning the farther extension to the east. West of the meridian of Toronto this
dividing ridge is continuous and still higher to the vicinity of Lake Huron. Here
its height is doubtless occasioned by the general elevation of the older geological
strata. Extensive deposits of gravel, however, are described by the Canadian geolo-
gists as extending along its northern slope to Collingwood and Owen sound (see Geol-
ogy of Canada, 1863, pp. 908, 909).

In the section which I specially studied in York county the features were in every
respect those characteristic of a terminal moraine, corresponding as closely as is pos-
sible to the features presented on Cape Cod and in the kettle moraine of Wisconsin
and the coteaus of Dakota. Through the south part of the township of Whitchurch
it consists of a line of massive knolls and ridges of unmodified drift enclosing numer-
ous kettle-holes and lakelets, forming the watershed between Lake Simcoe and Lake
Ontario. On the northern slope it is bordered at very near the summit level with ex-
tensive deposits of stratified sand and gravel. Still farther to the north the land de-
scends rather rapidly to the level of Lake Simcoe — that is, to about the 600-foot level.
Lake Simcoe would thus appear to occupy a vast space which was filled with ice dur-
ing the time that these Oak Knolls were accumulating as a terminal moraine.

The explanation suggested to me while on the ground, and later when coming up
from Lake Simcoe past Holland Landing and Newmarket to King station on the
Northern railway, was as follows : In the recession of the ice-sheet, when it had
reached the line of the Oak Knolls extending east and west from the vicinity of
Kingston to Lake Huron, it remained stationary long enough for the accumulation
of a vast terminal moraine which was high enough and solid enough to serve as a
barrier to the outflowing waters which accumulated behind it in the further recession
of the ice. Thus these stratified sands and gravels upon the north side of the Oak
Knolls mark the margin of a glacial lake whose drainage worked off to the east
somewhere in the vicinity of Kingston, and I should expect that a minute examina-
tion of the country would show evidences of this. Probably, however, this ridge
existed as a long island, projecting above the surface of that great glacial lake which
Professor Claypole has denominated Lake Erie-Ontario, and whose outlet was through
the pass at Fort Wayne, Ind., into the Wabash river. But the melting of the ice in the
rear of the moraine would cause currents to pass around in front of the ice eastward
along the northern margin of the moraine, and thus account for the special deposits
of sand and gravel there to be observed.

As obviating some objections to this theory, it should be borne in mind that in es-
timating the extent and continuity of the obstruction furnished by this moraine, we
are not limited to the deposits as they now exist. While a moraine is forming, vast
masses of ice arc covered up by the debris, and, thus protected, may remain for a
long while to add to the apparent height of the deposit and to serve as important ele-
ments in the obstructive barriers presented.

546 PROCEEDINGS OF NEW YORK MEETING.

Professor .1. W. Spbni br: I am very familiar with the region visited by Professor
Wright. The deposits referred to were described by the Geological Survey of Canada
many years ago, and more recently I have systematically traversed most portions of On-
tario. I f I understand correctly the epitome given by Professor Bitch cock, the Pleisto-
cene deposits southward of Owen sound, called by the ( lanadian Burvey the Artemisia
gravel, are regarded by Professor Wrighl as of one and the same series with those of the
zone parallel t" 1. 1 ■ « - north Bhoi f Lake Ontario. 1 Ju t the deposits of the two locali-
ties are not identical. Those in the peninsula between the three greal lakes— Ontario,
Erie, and Huron — r:n 1 i :t t « • more or leas in all directions, and occupy the highest land
in the country, ranging from 1,700 feel above the sea downward. The deposits are
made up of three Beries of till, of gravels of kame and osar structure, and of beach
formations. The ridges north of Lake Ontario, railed by the names of Oak Hills,
<>ak Knolls, etc., have a general trend parallel to the lake for over a hundred miles,
and have a maximum altitude of less than 1,200 feet. The Artemisia gravels are not
found with these drift deposits. On the ridges, at elevations above the beaches of
the Ontario basin, there are but few gravel deposits, for the country is generally too
low for the formation of high-level beaches, which are embraced in the Artemisia
gravels of the higher lands of western Ontario.

The next paper on the programme was read by the author. It ia repre-
sented by the following abstract:

rill; 801 ["HERN EXTENSION OF THE APPOMATTOX FORMATION.

i!V w J MCQEK.

[Abstract.']

[n a paper entitled " Three Formations of the Middle Atlantic Slope," published
in the American .Journal of Science early in lsvs.j a distinctive late Tertiary forma-
tion, well displayed on the Appomattox river in eastern Virginia, was defined and
named after that river, and its principal characters, it- distribution, its stratigraphic
relation-, and its probable age were briefly recorded. The formation was then known
to consist of a -•■rie- of predominantly orange-colored non-fossil iferous -and- and claj -.
resting unconformably upon Miocene and older formations, and unconformably over-
lain by the Columbia formation; it was known to expand southward from a thin and
discontinuous bed exposed in a narrow bell "ti the Rappahannock river so rapidlj as
t.> form a terrane many miles in width on the Roanoke; and it wus inferred to repre-
■ at least a pari of the ■• Orange Sand " of Hilgard and other southern geologists.
Recent researches have shown that tin' formation extends and expands southward
from the Roanoke rivei constitute the most extensive and conspicuous terrane

of the southern Coastal Plain on both Atlantic and Gulf slopes. The materials of the
formation under-" some change in the i larolinas : tin- element of pebbles i- less con-
fer the uplands and more conspicuous along the rivers than in the middle

Atlantic slope; wlnre the formation rests directly upon or cl ly approaches the

-talline terrane, and in ises where it reett directly upon the Potomac, con-

rable quantities of ark enter int i it- composition : but tie' most notable change

• Printed in fmi In the tin. i"ur Sol for Julj >l. xl, pp. i •"■ 11.

W J MCGEE — THE APPOMATTOX FORMATION. 547

is in the direction of more complete admixture of the sand and clay elements in the
form of a moderately homogeneous loam. Still further southward the same characters
are generally maintained, although in central South Carolina and in some other local-
ities the hue of the formation is exceptionally rich and dark. Local variations also
occur at different points in Georgia, Alabama, and Mississippi ; and these may inva-
riably and certainly be assigned to the influence of contiguous formations or other
local conditions. So the Appomattox formation, as now known, may briefly be de-
scribed as a series of obscurel}7 stratified and frequently cross-bedded loams, clays and
sands of prevailing orange hues with local accumulations of gravel about waterways,
the materials varying somewhat from place to place and always in the direction of
community of material between the formation and the older deposit upon which it
lies; while as a whole the deposit retains so distinctive and strongly individualized
characteristics as to be readily recognizable wherever seen.

. The formation has been actually observed in thousands of exposures within a zone
of fully 50,000 square miles, commencing a few miles north of the Rappahannock at
Fredericksburg and extending southwestward between the Piedmont fall-line and
the inland margin of the Coast Sands (a phase of the Columbia formation) through
the Carolinas to central Georgia, and thence westward through Alabama and the
greater part of Mississippi. If the direct observation be supplemented by legitimate
and necessary inference, the formation must be so extended as to bridge the valleys
from which it has been degraded, and to stretch beneath the various phases of the
Columbia formation well toward the Atlantic and Gulf coasts; and with this legiti-
mate extension the field of the formation becomes essentially coextensive with the
Coastal Plain of the Atlantic and eastern Gulf slopes (exclusive of a part of Florida),
and assumes an area of 250,000 or 300,000 square miles. The amount of erosion suf-
fered by the formation in different parts of its area is significant, since in many cases
it is evidently connected immediately with the local composition and remotely with
the composition of the sub-terrane. Thus, the formation is generally preserved upon
loamy and clayey belts, much more seriously invaded by erosion upon sandy terranes,
and largely eroded from calcareous terranes.

In stratigraphic relation, the formation unconformably underlies the Pleistocene
deposits (representing the southern extension of the Columbia formation), and un-
conformably overlies the various older formations of the Coastal Plain from the
probably Miocene Grand Gulf to the early Cretaceous or late Jurassic Potomac. In
some cases the Appomattox was laid down mantlewise upon strongly sculptured sur-
faces of older formations ; when the land lifted at the close of the Appomattox period
the waterways resumed their old lines, and the old sculpture was renewed ; then the
Columbia formation was similarly spread upon the Appomattox surface, and subse-
quently carved into like configuration ; and this complex history has given rise to a
complex distribution and interesting structural relations of the formation.

No characteristic or diagnostic fossils have thus far been found in the Appomattox
formation; but its stratigraphic position, unconformably below the Pleistocene and
unconformably above the Miocene (?), indicates an age corresponding at least roughly
with the Pliocene. It represents a considerable part of a more or less vaguely de-
fined series of deposits, variously called "Orange Sand," "Drift," "Quaternary,"
"Southern Drift," etc. ; yet since this vaguely defined series included not only the
Appomattox but also the basal gravel Led of the Pleistocene loess, parts at least of
the Cretaceous or Jurassic Potomac formation, and other deposits of various ages,
none of the old designations can be retained without material modification in delini-

548 PROCEEDINGS OF NKW V'ORK MEETING.

tion : and it therefore seems wise t'> extend the terra applied to the formation in the
region in which it was tir-t discriminated.

The sources of the materials of the formation have been fairly well ascertained:
The pebbles were derived in j «:i it from the Potomac formation of the immediate vicin-
ity, in part from the quartzite ridges and quartz v. 'ins of the Piedmont region and the
Blue Ridge, in part from the silicious dolomites of the central Appalachian zone, and
in part from the chert-bearing formations of the western Appalachian slope; and
these pebbles were evidently distributed by the rivers flowing along the lines of the
present great waterways of the region. A considerable elemenl of the loam came
from the Bame Bources ; but a part of it i< always local and reflect taracteristics

of the various sub-terranes.

In brief, the Appomattox formation forms a widespread terrane almost contermi-
nous with the Coastal Plain between the Rappahannock and the Mississippi; audit
i- an easily recognizable structural and chronologic unit, entitled t.> first rank as a
datum formation from which the stratigraphy and geologic history of the seaward p
tion of the Coastal Plain may be reckoned downward and backward. Although its
wide extent and essential unity have been established by a large number of observa-
tions, the exposures have 1 n correlated and the observations systemized by a method,

which may be characterized as horn largely inspired and well illustrated by this

formation. This method is Bet forth in detail elsewhere.

On the close of the reading of this paper the Society adjourned to meel in
t he evening at 8 o'clock.

After the r< cess Mr. McGee gave a brief synopsis of the paper, which was
followed by tin' discussion appended :

Professor C. II Bitchcock : I would like to inquire if Mr. McGee can tell us the
precise relation- of this formation ? Where doe- it come in contact with the Pliocene :
and I do not quite understand its relation- to the Pleistocene?

\l McGke: The formation is probably the exact stratigraphic equivalent of the
Pliocene. En central South Carolina it is overlain by the Pleistocene Columbia for-
mation and unconformably overlies the Miocene deposits, while fifty miles easta ard,
in the neighborhood of Charleston, fossiliferous Pliocene deposits are similarly inter-
calated between the Pleistocene Columbia formation and the fossiliferous Miocene
formation-.

Professor W. M. Davis: If I undersl 1 Mr. McGei correctly this afternoon, he

said thai the present Btreams follow inequalities which exist in the Burfai f the

Columbia formation. I mi i thai the Columbia formation is redly only a mask over similar

inequalities in the previously eroded Burfa f the earlier formations. The question

ari- what terms should beapplied to streams of that kind ? Among the several

terms that are now applied to rivers none fairly describe such examples as tl The

on- are not strictly consequent on the Columbia, because the Columbia form is

tliut of the underlying Ap] attoi formation : and they could hardly be said to be

superimposed on the Appomattox, because their location accords too well with it- -ur-
facp, Bas any name been in the roind of the author for such Btreams? It is a diffi-
cult matter to invent pertinent name- i hat will be acceptable in general use; and yet
in bo clear a this of a new Btyle of streams some new name must be introduced.

Mr VIcGi i : The class of rivers which I have described as cutting the Columbia and
Appomatto] formations alike is one which ha- definite existence, but for which no

W J MCGEE THE APPOMATTOX FORMATION. 540

name has hitherto been proposed. The class, too, is more comprehensive than Pro-
fessor Davis' question might indicate. In the Buhrstone hill-land a well-defined drain-
age was established in late Eocene time; and rivers, streams, brooks, rivulets, down
to the minutest rills even, and a corresponding topographic system, were developed.
Subsequently the Grand Gulf formation of the Miocene was laid down and the old
surface was buried in part, yet not so completely buried but that the post-Miocene
drainage coincided with the pre-Miocene drainage. Then came the Appomattox for-
mation, which was spread like a mantle over the surface; and upon it the primary
drainage was once more renewed. Afterward the Pleistocene Columbia formation
was laid down ; and then for the fourth time was the drainage outlined on the original
lines. This class of drainage has not hitherto received a designation ; but from its
mode of origin it might be called resurrected, or palingenetic.

Mr. C. D. Walcott : I have listened with a great deal of interest to Mr. McGee's
paper, because it describes the determination of a geologic horizon over a great area
without the aid of paleontologic data. It is true that the underlying unconformable
series is determined by the contained fauna and gives the approximate horizon, but it
is very rarely that we have an illustration of a satisfactory attempt to identify by the
stratigraphy alone a formation so widely distributed as the Appomattox.

Professor James Hall : The communication shows very clearly that physical geol-
ogy can be successfully carried on without the use of fossils.

The next paper was —

THE VALUE OF THE TERM "HUDSON RIVER GROUP " IN GEOLOGIC

NOMENCLATURE.

BY C. D. WALCOTT.

It was discussed by James Hall, W. M. Davis, and Mr. Walcott. The
paper and discussion are published in full among the memoirs, pages 335-
.356 of this volume.

The following papers were then read :

THE CALCIFEROUS FORMATION IN THE CHAMPLAIN VALLEY.

BY EZRA BRAINERI) AND II. M. SEELY.

THE FORT CASSIN ROCKS AND THEIR FAUNA.

BY R. I\ WniTFIELT).

Both of these communications are printed in full among the memoirs,
orming the preceding pages 501-516.

The Society then adjourned until 10 a. m. of the next morning

LXXiri— Rum Geol. Soc. Am., Vol. 1, 1889.

Sf>>i<>n mi s.\ ri;iti)Av, Dhckmker 28.

The Society mel al 1<> o'clock a. m., President Hall in the chair.

Several announcements from the Council were made, after which the Sec-
retary read a letter from Mr. Munis K. Jesup, President of the American
Museum of Natural History, regretting the inconvenience to which the
Society had been subjected owing to the unfinished condition of the build-
ing, and pledging a cordial welcome in case the Society should desire again
to meet in the Museum.

Professor ( ope moved a vote of thanks to the officers of the Museum, which
was carried unanimously, and the Secretary was directed to send a suitable
letter to Mr. Jesup as representing the Trustees of the Museum.

Professor W. M. Davis offered the following resolution :

Resolved, That a committee of three be appointed to confer with similar
committees from the societies of Naturalists and of Physiologists in regard

to the places and times of future meetings.

The resolution was adopted. The President appointed as such committee

W. M. Davis,

Alex. Winched,
J. d. Stevem-on.

The discussion of the papers read before adjournment last evening was
next in order. ( '. D. Walcott, ( '. II. Hitchcock, E. Uraincrd, and James
Hall took part. The papers are published among the memoirs as above
noted.

The next paper was read, in the author's absence, by Mr. C. D. Walcott.
1 1 is entitled —

THE STRATIGRAPHY OF THE "QUEBEC GROUP."

BY n. W, ki.i.s.

It is published in full, forming pages 453—468, plate 10, of this volume.

The next paper was —

THE CUBOIDES ZONE \M> il- I IUNA J \ DISCUSSION OF METHODS OF

CORREL \tion.

r.v ii. -. WILLIAMS.

Remarks upon this paper were made by C. D. Walcott. It is published
among the memoirs, pages \81 500, with plates 1 1-13.

SO)

G. H. WILLIAMS — OBSERVATIONS IN NORWAY. 551

The next paper read is represented by the following abstract :

GEOLOGICAL AND PETROGRAPHICAL OBSEKVATIONS IN SOUTHERN AND

WESTERN NORWAY.

BY GKORCiK U. WILLIAMS.

\_Abstract.~\

The communication embodies the results of certain observations made by the author
during the summer of 1888 in southern and western Norway, under the guidance of
Professors Brogger and Reusch of Christiania, and in company with Professor Rosen-
busch of Heidelberg and Dr. A. C. Lawson of the Geological Survey of Canada.

The points of special interest relate to the subject of metamorphism, which was
studied on a series of excursions in two regions exhibiting, in sharp contrast, the
effects (1) of the contact action of large eruptive masses upon nearly undisturbed
Silurian strata ; and (2) of intense dj'namic action in metamorphosing both igneous
and sedimentary material in a region of great orographic disturbance.

Since the early travels of Von Buch and Naumann, the region about Christiania
has been classic as an example of the metamorphism produced at the contact of great
eruptive masses ; but the recent elaborate studies of Brogger show how much of value
there was to reward a detailed examination of this same Held.

Large areas of post-Silurian syenite, granite and porphyry have broken through
the nearly horizontal Silurian beds, composed of thin, alternating layers of dark ar-
gillaceous, and light-colored calcareous material. The metamorphism is confined to
the immediate vicinity of the contact, and is progressive — i. c, proportional to the
nearness of the eruptive rock. The most intense action is shown upon fragments in-
cluded wholly within the syenite.

In the region abost the Langesundfjord, southwest of Christiania, the conditions
and are about the same, except that the metamorphosing agent is here nepheline-
syenite, and particularly interesting on account of the great number of rare minerals
which it contains. Two points worthy to arrest attention are (1) the extent to which
the metamorphism of a sedimentary rock can be carried without destroying its fossils ;
and (2) the metamorphosing effects of eruptive masses upon other rocks themselves
eruptive.

A specimen of limestone was exhibited from the immediate contact with the nephe-
line-syenite, near Brevig. It is completely changed by contact action, as is shown by
the microscope, to an aggregate of garnet and diopside, and yet remains of crirfoidal
columns are still plainly visible in it.

The action of the syenitic rocks upon dikes of basic eruptives, present in the Silu-
rian beds before the intrusion of the more acid masses, is of interest, inasmuch as the
paramorphism of pyroxene to hornblende, which is now recognized as such a common
result of regional metamorphism, is here seen to have been accomplished by contact
metamorphism alone.

A description was also given, illustrated by a diagram and specimens, of the Horter-
kollen granite mass, which has raised the overlying Silurian strata in the form of a
laccolite, though its base is not visible, and hence it is not definitely known whether
or not the sedimentary beds lie below as well as above the intrusive mass. This
mountain lies about twenty miles due west of Christiania, and is fortunately exposed
on its south side in a natural section from base to summit. The structure of the

552 PROCEEDINGS OF NEW YORK MEETING.

granite is coarse below but rapidly becomes Bner grained toward the contact, and is
almost cryptocrystalline along the edge of the sedimentary beds. The thick cover-
ing of Silurian strata is continuous over the entire mass, their dip following the con-
tact, even down the Bteep eastern Blope. The metamorphism of these overlying beds
is plainly due to the granite, and anastomosing dikes of the latter rock penetrate them
vertically, but without reaching the present surface.

On leaving the Christiania region for the western coast of Norway, the opportu-
nity was enjoyed of examining the regionally metamorphosed eruptive and sedimen-
tary rocks near Bergen, under the guidance of Professor Bans Reusch, whose well-
known works* on the geology of this district have given it a world-wide fame. The
remarkable mica-schists of Vagtdalen were visited, containing, in spite of their highly
crystalline character, well preserved remains of trilobites and orals. Moreover,
where the metamorphism has completely destroyed the fossils in the Bchists, they are
often preserved in intercalated calcareous lenses. (Specimens of all these rocks were
exhibited to the Society.)

Much more of importance in its bearing upon regional or dynamic metamorphism
was seen near Bergen and on the island of Bemmelo, further to the south. Time,
however, forbids the further entering into detail; but the series of specimens will
serve. Letter than words, to illustrate to those who are interested in the subject, what
are the most striking facts.

Suffice it, in conclusion, to indicate certain points which seem capable of general
application to metamorphic rocks, and to the truth of which these observations in
Norway offer strong corroborative testimony:

1. The mint ralogical changes produced in a given rock by both contact and dynamic
metamorphism are in general similar, while the structural alterations brought about
bv the .-aine agencies are usually in striking contrast. In tic case of the basic erup-
tives above mentioned the paramorphism of pyroxene to hornblende is accomplished
either within the contact zone of syenite or by orographic pressure; although it is
only bv the latter mean- that the rock is converted into a schist by the- development

of foliation.

2, [f the action of dynamic metamorphism i- carried far enough it is capable of
producing the Bame result from rocks originally most distinct in character and origin.
An eruptive ma-- and a sediment, if sufficiently alike in chemical composition, may,
when subjected to intense pressure, develop into foliated rock- whi< h cannot be dis-
tinguished. It i-, therefore, | ible to trace out the origin of the crystalline schi

only .up to a certain point. We may separate those which are igi us from lie

which are (da-tic, bo long a- any distinctive characters remain ; but if, as is very often
the case, the original structure has been obliterated by metamorphism, such a Bepara
lion becomes hopeli

Professor J. S. Newberry: 1 would ask Professor William- to add a Bingle fact
to the very clear and interesting exposition he has given to us. How far has there
been, in these different cases, substitution or transfer of material? I would ask it
he ha- the chemical < Btitution of the unaltered and tic altered rocks to compare.

p -v Williams: This differs very much in different cases. Bere we havea

limestone transformed into an aggregate of garnet and pyroxene; this mean- a very
considerable substitution. Some limestones are, however, silicious : and a highly siti-

Isted mi.. German
v i Ingliah BUtnm urv "i • lenl

G. II. WILLIAMS — OBSERVATIONS IN NORWAY. 553

cious and highly magnesian limestone would not require a great addition of material
to change it into an aggregate of garnet and diopside. As regards the basic rocks, I
cannot speak with as much certainty of the Norwegian occurrences as of other rocks
of a similar character in the neighborhood of Baltimore, where like changes have
been produced by regional metamorphism. Here the resulting products, composed of
feldspar and hornblende, do not in any particular differ in chemical composition from
the original rock, composed of pyroxene and feldspar.

Professor B. K. Emerson: I desire to add a word, partly from interest in the
speaker and in recognition of the admirable way in which the matter has been pre-
sented by him, and partly from reminiscences that came up of travel many years ago
in the region he has described. This discussion of regional metamorphism brought
to my mind the work of President Hitchcock upon the same subject, and especially
his work on the fossiliferous Devonian schists at Bernardston, Massachusetts. On
examining a large series of these Bergen specimens with Professor Rosenbusch a few
years ago, I found that the Bernardston Devonian locality described so long ago by
President Hitchcock and Professor Dana affords representatives of all, or the major
portion of those rocks — quartzite with all the pebbles rolled out and cut sharp by
faulting and jointing, hornblende schists in every variety except those which seem to
have come from the- metamorphism of eruptive rocks (that is, hornblende schists
that seem to come from the metamorphism of limestone but show no trace of tufa or
volcanic origin), beds of the most compact and pure magnetite with fossils immedi-
ately above and below them, and these fossils in highly crystalline limestone cut
through by granite veins and in mica-schists piece for piece like those taken from
Bergen. These things, like the facts of history, have to be re-described and re-written,
and come at last to be believed. Of course the work of President Hitchcock was done
without the aid of the microscope, and it was pushed far beyond the limits of the
field at Bernardston.

I was surprised in passing recently one of the college buildings at Amherst which
is built of gneiss to see that several of the blocks showed the altered pebbles of the
conglomerate of which the rock was made. This is the so-called Munson granite
that stretches across the state east of Amherst; and that same conglomerate granite
wraps around the Archean of the western part of the state and forms there a coarse
shore deposit. This granitoid gneiss was supposed by President Hitchcock to be the
last term of the metamorphism of a conglomerate. It seems to me that the distinc-
tion between the regional metamorphism and the metamorphism caused by manifest
contact of eruptive rock, where the two effects are superimposed, will be found in the
introduction in the latter case of chemical materials that have been brought up with
the eruptive rocks. Any contacts which show, as those I have studied in Massachu-
setts, the presence of minerals containing boracic acid and a large increment of alka-
lies, as compared with the same bed more removed from the intrusive rock, enable
one at times to distinguish quite clearly between the regional and the contact effects.
This is especially clear with aluminous sediments when the normal metamorphism
develops chiastolite, ottrelite, staurolite, garnet, graphite. The contact influence of
the eruptive adds coarse muscovitc in abundance, feldspars, tourmaline, cordierite, and
suppresses (resorbs) for the most part the purely aluminous silicates of the first group,
though their former presence may be noted by their pscudomorphs in muscovitc.

554 PROCEEDINGS OF m;\v ¥/ORK MEETING.

The next paper ia represented by the following abstract:

CRETACEOUS PLANTS FROM MARTHA'S VINEYARD.
I;V DAVID WHITE.*

[Abstract."]

An historical review of the opinions of geologists, during the first half of this cen-
tury, concerning the age of the strata extensively exposed at Gaj Head, at the western
end of the island of Martha's Vineyard, shows a general agreement in correlating
those strata with the Alum bay clays in the [sle of Wight, chiefly on account of their
stratigraphical resemhlance. Specimens of a Cretaceous fauna have been found, but

the rolled appearance of these and the present F mure recent fossils in the Bame series

have led to the conclusion tliat the Gay Head terrane is of lower or middle Tertiary
age. Within the last year, however, this series has been the subject of an elaborate
stratigraphical description by Professor N. S. Shaler, who, in his report on the geol-
ogy of Martha'.- Vineyard, names it the "Vineyard series," and concludes, without
adducing the paleontologic evidence, that it is late Miocene or l'li ne.

A careful search made last summer, in company with Professor Lester F. Ward, of
the IT. S. Geological Survey, resulted in the discovery and collection of plants in the
carbonaceous clays in the Vineyard scries at several points about Gay Head, at
Peaked hill, and at Nashaquitsa, and from concretions found in the first and last
named localities. Fossil wood was found wherever the series was met with. The
collection, which bears an archaic aspect, embraces cryptogams, gymnosperms, and
angiosperms. Most of the species Beem unlike any before described.

Of the species as yet identified, Sphenopteris grevillioides, Mr., has been found also
in the Kome (lower Cretaceous) beds of Greenland; Sequoia ambigua, llr., occurs in
the Kome beds and the lower Atane (middle Cretaceous) of Greenland; Andromeda
parlatorii, llr., formerly described from the Dakota group of Kansas and Nebraska,
has also been identified in the lower Atane of Greenland, and from strata probably
of Cretaceous age in the Bozeman coal mine- of .Montana; Myrsine borealis, llr.,
occurs in the " Liriodendron bed " (lower Atane) in Greenland; Liriodendron simplex,

Newb'y (/>. Meekii, Hr., in part), »f the few Bpecies as yet published from the

Amhoy clays, is one of the most abundant Bpecies in the flora at Gay Head, where it
i~ found associated with forms identical with some found by Beer in the famous
• • /. Iron bed" of the lower Atane, and in the Patoot (upper Cretaceous) of

Greenland; a Sapindus, probably referable to S. Morrisoni} Lx., has been found in
the Dakota group of Nebraska and the Patoot beds of Greenland ; Eucalyptus gei-
nitzi. llr., next in abundance, has been found in the " Liriodendron bed " of Green-
land, is abundant in and characteristic of the middle Cretaceous of Bohemia, and

. appears at the same stage (Cenomanian) in Moravia. The remains of the /■■'

lyptus nuts arc' marked by furrow- tilled with a fossil resin " indistinguishable by
ordinary te-t- from amb The fossil content- of these oil or gum vessels suggest

that a part at least of the so-called amber found about Gay Head and in the Creta-
Ji ey, where also eucalypts occur, may be the fossilized exudation of
the contemporaneous " gum-trei
All the previously described species thus far identified at Gay Head have been found

lusively in the Creta i, and all but Sphenopteria grevillioides were present in

the middl> i Llthougl r flora seems to be more directly related to that

Printed in full in the am. Jour. 3cL t-r February,

D. WHITE — CRETACEOUS PLANTS PROM MARTHA'S VINEYARD. 555

of the middle Cretaceous of Greenland than to that of the Dakota group, there is every
reason for believing that it will prove to be largely identical with the rich but as yet
unpublished flora of the Amboy clays. The Gay Head flora indicates an age certainly
Cretaceous, and probably middle Cretaceous, for the terrane in which it was deposited.

The occurrence of Tertiary elements in the fauna of the Vineyard series raises
the question as to whether the plant-bearing concretions are not exotic. The structure,
composition, number, size, position, and relations of these concretions to the contain-
ing matrix join in indicating their present existence in the place of their original
formation. Numerous stems and fragments, together with the eucalypt fruits, are
found in the matrix of the limonitic conglomerate. The extra-concretionary plants
found in the carbonaceous clays at various horizons, though mostly indeterminable,
seem to agree with the species found in the concretions. At Nashaquitsa the con-
cretions were observed by Professor Ward and myself apparently in the process of
formation, the leaves sometimes lying partly within the concretion and extending
outward into the homogeneous matrix.

Similar plant-bearing concretions are found in the Amboy clays on Staten island
and in New Jersey. The extension of these middle Cretaceous clays as far eastward
as Glen Cove on Long island is now generally accepted. If the Vineyard series is
not itself a farther extension, it must, at least, have been derived in part, and witli
the minimum distance of transportation, from such a continuation of the middle Cre-
taceous to the eastward, along the south of New England.

The present paper is the result of a preliminary study. Before the age and origin
of this series can be unquestionably determined, there is need of further work in all
branches of its paleontology, taken side by side with the study of its stratigraphy.

Dr. J. S. Newberry : This is the first opportunity I have had to see any of the
plants spoken of by Professor Shaler, but there can be no doubt that they represent
the flora of the Amboy clays. I have been collecting fossil plants from New Jersey
for the last twenty years, have already some thousands of specimens, and have fifty
plates of this Amboy flora drawn and arranged for publication. I have traced the
Amboy clays from New Jersey across Staten island and along the north shore of Long
island to Sea Cliff and Glen Cove, and have long been of the opinion that the formation
extends the entire length of the island. Now, Mr. White has shown that it under-
lies Martha's Vineyard as well, for the leaves and fruits displayed on the screen
arc all found in the Amboy clays. I will not now say anything further about the
characteristics of the Amboy flora, only that it has some things in common with the
flora of the Dakota group, but contains many more plants found in the Atane beds of
Greenland and the Cretaceous clays of Aachen [Aix-la-Chapellej. Its geological
position is middle Cretaceous, or at the base of the White Chalk.

Professor Lester F. Ward : My principal object in coming to this meeting was
to listen to this paper, as I was associated with Mr. White in his work and am deeply
interested in it.

I desire merely to emphasize the great importance of the results at which he has
arrived. Not until the past season has anything definite been known of the fossil flora
of Martha's Vineyard, the few fragments figured by Hitchcock not having been
determinable and having no geognostic value. As Mr. White lias remarked, the
ablest geologists in the country have long been at work upon the question of the age
of the Gay Head beds, and, as shown by the older as well as by recent papers, espe-
cially those of Professor Shaler, great differences of opinion and doubt as to their age
have prevailed.

556 PROCEEDINGS OF M W YORK MEETING.

The discovery by Mr. White of undoubted C eta ous foBsil plants has settled that
question so far as the particular strata from which these plants were found arc con-
cerned. In :ill his recent papers, including the one read before the Society on Thurs-
day last (pp. MS 152), Professor Shaler has insisted that all except the very base of
the Gay Bead section is Tertiary ami even Mi ne <>r Pliocene.

I do nol pretend that the entire section at Say Head and Nashaquitsa cliff is n<

ly Creta* us. The plants were found in the Gay Eead section near the middle,

and it ie very possible that, considering the extent of the beds and the length <»f the
pection, the overlying strata may be Tertiary, even Miocene. But if there is a great
thickness lying above these beds, so there is a great thickness lying beneath them, and
therefore the section must extend far down into the Cretaceous. It would Beem then
that Mr. White's investigations during one short Beason have done more to settle the
age of these beds than all that has boon done before.

I gladly testify to the indefatigable zeal with which Mr. White pursued his inves-
tigations against the greatest difficulties and discouragements. It required much
careful thought and labor to ascertain in what particular manner the plants were

pr rved ; but after this had been- fully settled he was very successful in finding

then, although they were not abundant; and he persisted until his collection
amounted to live barrels of very excellent material, which is being elaborated at the
National Museum.

Mr. F. J. II. Mkrrill: It is seldom that an opportunity is afforded for determin-
ing the true stratigraphy of the Gay Head section. The speaker visited it in 1884 and
concluded as a result of his examination that the beds wen- extensively repeated by
faulting; but on visiting the locality in 1887, with Professor N. S. Shaler. he found
the aspect of the section bo much altered by landslides that he was unable to show the
evidence upon which he had based hig conclusion. Subsequent exposures have again
revealed the truth as reported by Professor Shaler at this meeting (ante, pp. II". 162).
During his Bret visit the writer found a number of clay-ironstone nodules enclosing
fragmentary leaf-prints, which were considered by \>v. Newberry t" be of Cretaceous
age, but the impressions were poorly preserved and their nidus in the section was
uncertain, bo that m> decisive value could he attached to them. Although the Creta-
ceous leaf-prints reported by Mr. White were undoubtedly in place, they do nol prove
th« Cretaceous age of the whole (Jay head section. They are from the lower half of
the series. The greensand beds, which are in the upper half, contain Miocene Tertiary
fossils, shark teeth of the genera Charcarodon and Oxyrhina, bivalve casts, probably
of Tellina biplicaia, Say, and fragments of crustaceans. This greensand deposit is
apparently secondary, having been derived iv.nu some pre-existing bed and ro-doposited
under conditions of disturbance and violence abnormal t.> greensand beds. The crus-
tacean fragments in particular have been much rolled and wave-worn. <»n this
evidence we may conclude that the greensand beds were laid down not earlier than
the close of the M iocene.

i e opinion of the writer that the Gay Head strata were p< L-Pliocene was chiefly
based on the evidence of a stratum of post-Pliocene sand, which is the uppermost
member throughout the section, being repeated frequently by faults and at one point
containing fragments of Venu» mercenaria and other Quaternary shells. A- 1 1 1 i - bed
i- apparently conformable to those beneath it, the writer concluded that a considerable
portion of th« Gaj head leries, if not the whole of it. was laid down in post- Pliocene
time. It may be, however, that future investigation will demonstrate tin. presence <>f
Crel I tiary. and Quaternary strata at Gay lead.

C. H. HITCHCOCK — OVAL GRANITOID AREAS. 557

After recess, the first paper read was —

SANDSTONE DIKES.
BY J. S. DILLER.

The paper was discussed hy W. M. Davis and B. K. Emerson, and is pub-
lished among the memoirs, forming pages 411-442, with plates 6-8, of this
volume.

This paper was followed hy —

ILLUSTRATIONS OF GLACIERS IN SELKIRK MOUNTAINS AND ALASKA.

BY A. S. BICKMORE.

A series of elahorate lantern slides were thrown upon the screen and
hriefly described.

The next paper was —

SOME RESULTS OF ARCHEAN STUDIES.

BY ALEXANDER WINCH ELL.

It gave rise to discussion by C. R. Van Hise and Professor Winchell.
The paper is published among the memoirs, ante, pages 357—39 I.

The paper represented by the following abstract was then read :

SIGNIFICANCE OF OVAL GRANITOID AREAS IN THE LOWER LAURENTIAN.

BY C. II. HITCHCOCK.

[Abstract.]

In the primitive crystalline regions, observers have noted that the supposed oldest
portions of the Laurentian consist of oval, ovoidal, elliptic, or variously elongated
ureas, usually foliated. Such are the formations called K,, K.,, K8by Percival in the
"Western Primary" of his Connecticut map, as well as his 15 of the " Eastern Pri-
mary." The first-named are part of a series that extend through western Massa-
chusetts into Vermont, and would be represented in the " Laurentian protazis of the
Green mountains " as described by Professor J. I). Dana in the Bulletin (J. S. A.,
this volume, page 36. In New Hampshire tiny may be represented by the porphy-
ritic gneiss and the Bethlehem gneiss. Dr. A. C. Lawson describes similar areas in

LXXIV— Bull. Geol. Soc. Am., Vol. t, 1889.

558 PROCEEDINGS OF NEW YORK MEETING.

the Rainy lake district ih of Lake Superior (Part F, Ann. Rept. Geol. Canada,

[887 Dr. A. Winchell has referred to similarcases in the paper just read.

The characteristic featu usually the following: 1. The area was originally

highest in the center, though now it lias reached the Benile topographic Btage. '2.
There is a concentric arrangement of the rocks and minerals. Thus, in a small ar«a
in Hanover, New Hampshire, the interior core displays porphyritic crystals of ortho-
clase, while the main mass consists of a rather coarse protogenic gneiss. The outer
band, not more than ](») or l'00 feet thick, has a superabundance of chlorite with

hiotite, hut must not I nfounded with what have been called Huronian schists in

the neighborhood. Thi- area is perhaps ten miles long and four miles wide. 3. T
foliated planes possess the anticlinal quaquaversal arrangement. Subsequent action
baa folded these planes just as if they indicated an original sedimentation.

The significance of these facts depends upon the interpretation i;iven to the foliation.
[f these represent lines of sedimentary accumulation, then the are:,- constitute the
very oldest known stratified deposits. As they are anticlinal in form they furnish no
evidence of a basin structure ; or if the older foundation exists it lias never been ob-
served. There seems to be no evidence of sedimentation in these basal layers — all the
supposed conglomerates of the Archean being situated in the upper part of the group.
The facta are at variance with a popular notion of an indefinite series of systems, each
one formed from another concealed from view. The areas described arc the oldest
known, or fundamental rock-.

If the other, or igneous view of origin be accepted, essentially the same view of
age must be entertained, for the -pace- between these primitive areas arc composed
of later Archean or Paleozoic rocks, and there are no apophyses or veins extending
into the newer series. Where these arc observed, as is claimed by Dr. Lawson, there
is reason to believe in their later igneous development. In tie icamined, every

part of the concentric structure i- apparently of the same age, the zonal condition re-
sulting from freedom of motion in a plastic mas- so that there may be a segregation

of like mineral constituents into separate hands.

The origin of the igneous masses may he compared to the building up of oceanic
islands of the presenl day from volcanic ejection. I have elsewhere suggested ■ that
in New Hampshire the rounded areas of the oldest rocks are numerous enougb to have
constituted an archipelago which may have been the beginning of the Archean con-
tinent in New England.

The area- of granite, syenite, and porphyry in the White mountains correspond
topographically with tbe supposed original Laurentian area-, hut they lack the planes
of foliation. Hence they cannot have been subjected to the influences which have
been brought to hear upon the former. Granting pondence between the two,
the one may represent youth and the other old age of igi us overflows.

Professor 6. II. Williams: It is interesting to Bee bow the -a me facts may suggest
to different mind-, different interpretation- After what I have Been in Norway and
elsewhere an explanation occurs to me exactly opposite to the one which Professor
Hitchcock ha- Led. The center of the mass is, I think, the youngest, while the

other layers are to be accounted for as having 1 n approximately horizontal Btrata,

pushed up by a molten mass rising from below after (he other material was formed.
This eruptive rock has altered the Btrata progressively from the center.

tddre lloa E, Proc. A. A. A. 8., vol. XXXII, 188.1.

B. K. EMERSON — PORPHYRITIC AND GNEISSOID GRANITES. 559
The next paper was —

rORPIIYRITIC AND GNEISSOID GRANITES IN MASSACHUSETTS.

BY PROFESSOR B. K. EMERSON.

[Abstract.]

Referring to an unpublished geological map of the central part of .Massachusetts,
and confining attention to the region between the Berkshire limestones and the Boston
basin, it was remarked that the country consists of a great series of mica, quartz, and
hornblende schists, all presumably Paleozoic, and eight principal bands of highly
feldspathic rocks (more or less interrupted), broad where they enter the state on the
north and narrowing southward, and for the most part terminating before reaching
the south line of the state. They are granites and granitoid gneisses, in small part
Archean, in larger part Cambrian, and in largest part intrusive.

The western band is a complex of Archean and Cambrian — a row of small Archean
ovals, exposed by erosion of the Cambrian conglomerates and conglomerate gneisses,
extending quite across the state. The Hinsdale area is typical of the Archean ovals.
A center of coarse allanite and magnetite gneiss surrounded by a band of coarse
limestone, like that of Ticondero^a, carrying phlogopite, chondrodite, etc. Outside
the limestone is a graphite gneiss carrying a characteristic blue quartz.

This Archean series is bounded by a broad area of a coarse Cambrian conglomerate,
mostly changed into a white biotite gneiss, like the quarry stone of Monsen and Pel-
ham. It is itself quarried extensively in Becket.

The Allanite gneiss dips beneath the limestone and so outward — the quaquaversal
arrangement is perfect, though no special weight is put upon this fact in determining
the age of the beds. This is deduced rather from the clearly Laurentian type of the
Archean gneisses and limestones, and from the facts (1) that the same conglomerates,
in their northward extension in Clarksburg, have been found by Mr. C. D. Walcott
to contain Cambrian fossils, and (2) that they rest in strong unconformity upon the
Archean series beneath.

This can be seen clearly in a fine exposure along the brook south of the Dalton Moun-
tain Club house, on the old Hinsdale-Dalton road. Archean areas of this type extend
across Massachusetts and Connecticut, but to the north are two ovals of different type —
the Hoosac tunnel and Clarksburg areas. Here the same Cambrian conglomerates
and white biotite gneisses surround areas of a coarse porphyritic granite ; and .Mr.
J. E. Wolff, who has developed this difficult territory with the greatest perseverance
and success, considers these granites certainly pre-Cambrian, and has proved conclu-
sively that the conglomerates are unconformable upon them.

The broad band that crosses the state east of the Connecticut, containing the North-
field and Pelham quarries, agrees with tin' Cambrian conglomerate in character and,
I think, in age. It is a broad, very flat anticlinal, throwing oil' the whole schistose
series on either flank. It shows traces of pebbles here and there, and contains a great
bed of slightly actinolitic quartzite.

The other bands come under a different category. They lie along large synclinals
instead of anticlinals. They are commonly biotite granite — line grained to coarse
porphyritic — rarely varying to muscovitic and hornblendic varieties. The texture

560 PROCEEDINGS OF NEW YORK MEETING.

varies from maseive to distinctly foliated, and the contacts on adjoining rocks are
those of intrusive masses.

I would call these great bodies of granite batholites, employing the word suggested
by Bdouard Suess, after the analogy of the word "laccolite," coined by Mr. G. K.
Gilbert. They have melted their way up through a great thickness of the folded strata,
often absorbing much of the latter into their own mass. This is well shown in the
central batholite in the Beries west of the Connecticut, which extends across Hatfield
and Williamsburg. In its eastern third it cuts through a great thickness of horn-
blende schists, ami i- a heavy hornblende granite. In its middle third it comes in
contact with less hornblende schist and with much limestone, and it is here a born-
blende-biotite granite. The remaining western portion is bounded and was formerly
covered by muscovite-biotite schists, and the granite is here white, with little biotite
and often much muscovite. The great mass is cut everywhere by a very great num-
ber of dikes of a coarse muscovite granite, which seem to represent later intrusions
iif the central portion of the mass into shrinkage cracks in the already cooled periph-
eral portions, and thus to represent more truly its original composition.

The batholites lie in several series of ovals parallel with the strike (or these are
fused into single broad bands) along the centers of great synclinals, the weakening
along the base of the latter having furnished a favorable outlet for the fused material.
The Burface of contact between the granite in these batholites and the superincumbent
Bchists imi-i have been very irregular, and a broad area of contact metamorphosis
must have extended out from this surface; and the various sections presented by dif-
ferent erosion surfaces enable as to reconstruct the batholite with some fullness.

Thus, in the center of the Worcester argillite is a broad oval where the argillite is
changed to a pure mica schisl filled with the chiastolites found in all cabinets. There
is no trace of granite for miles around, but 1 have no doubt that the change in
the argillite is due to a buried batholite, like those a few miles Bouth in the city of
Worcester.

Again, where the schists are vertical, sheets may have extended deeply into the

plastic ma88 and have retained their dip and strike because they retained their con-
nection with the superjacent Bchists. Thus in the Hatfield batholite, starting from
the hornblende schist, one finds in the line of its strike for several miles across the
granite fragments of the schist with true dip and strike, and. in the line' of the lime-
stone and the mica schist, similar fragments of these rocks. When the rocks are
more nearly horizontal, great Hoes of the schists float upon the granite, as the Bbrolite
schists on the Belchertown granite, and the Carboniferous conglomerate upon the
Harvard granite.

I i zonal character of the contact metamorphosis around these batholites is in-
teresting, especially in aluminous Bediments. The first wave of heat develops the easily
formed minerals, fibrolite and chiastolite ; stronger heat, Btaurolite and game) : then
the first influx of alkaline waters from the granite form- pseudomorphs of these in
muscovite, and with increasing heat feldspars develop. So the highly altered rocks

iresl the intrusive mass have often passed through all the stages one passes over in
going from the outer /.one inward. Thus, in the Carboniferous argillite in Harvard
■ me finds masses of interlaced prisms of andalusite, of the largest size and finest pink
color, enclosing crystals of fibrolite in abundance (the two nol orientated to each
other), and the whole in every stage of change i" coarse muscovite. This pres< i
three stages which were plainly passed over in succession, and nearer the granite

B. K. EMERSON — PORPHYRINIC AND GNEISSOID GRANITES. 563

large feldspars are interspersed. In the Hatfield argillite, a zone of delicate chias-
tolites is succeeded inwardly by a zone where the chiastolites are changed to a mixture
of muscovite and minute twins of staurolite (the mass still retaining the shape and
black cross of the chiastolite) by the influence of greater heat and alkaline solutions ;
and nearer the granite the whole changes to sericite schist, chlorite schist, and finally
hornblende and feldspar appear near the contact with the hornblende granite.

The outcrops which have been discussed have for the most part been called granites
heretofore. This, however, is true of them, that they arc often entirely indistinguish-
able from the Cambrian conglomerate gneiss where both are developed as medium-
grained biotite granites.

The more perplexing cases remain for consideration. These are the broad bands of
biotite granite, often well foliated, which stretch across the state with a width of five
to twenty-five miles. They may be called the Princeton, Barre, Athol, and Orange
bands. The Princeton band starts at the north west corner of Worcester and, gaining
soon a width of ten or twelve miles, runs north through Pitchburg, where are great
quarries, and on into New Hampshire, where it is called " Concord granite " by Pro-
fessor C. H. Hitchcock on the map of the second New Hampshire survey, and classed
as " Montalban.''

On being mapped, it cuts across the Carboniferous and older schists as an intrusive
mass. Though often foliated, it is more often massive, and its foliation cannot be
harmonized with that of the adjacent schists. It has a clear zone of contact metamor-
phosis— fibrolite schists changes to garnet and staurolite schist, argillite to chiastolite
schist, quartzite becomes gneissoid, and tourmaline is developed for miles along the
border.

Lying in the middle of this granitic area, Mount Wachusett is in structure dis-
tinctly laccolitic, and owes its existance to a great mass of fibrolite schists — a portion
of the former cover of the batholite. If abook be laid on its side with its ends directed
north and south and a slight pressure be exerted on the leaves till they bend up
slightly and separate, forming three or four lens-shaped cavities, then will the leaves
represent the fibrolite schists, and the cavities the intruded granite ; and if now the
eastern half or three-fourths be removed, the remainder will be a good model of the
mountain.

I am compelled thus to consider the whole great mass, more than fifty miles lung
and above five miles wide, as an elongated batholite occupying a large synclinal in
the schists. The Athol band is still more clearly an intrusive block. The other two
combine so equably the peculiarities of the Cambrian conglomerate gneisses and the
batholitic granites just described that I hesitate as to their interpretation.

By reason of the pressure for time, the next paper on the programme was
read by title only. It was —

THE PEE-CAMBRLVN ROCKS OF Till'; BLACK HILLS.
BY C. B. VAN HISE.

The paper is printed in full among the memoirs, forming pages 'JO'J-244,
with plates 4 and 5, of this volume.

562 PROCEEDINGS OF NEW YORK MEETING.

The paper next in order was read by the author:

THE [NTERNAL RELATIONS \ N I » TAXONOMY OF THE &.RCHEAN OF CEN-
TRAL CAM \l> A.

BY A. C. I. LWSON.

Owing tu tin' shortness of time left, there was no discussion on this
communication. It forms pages 175—194 of this volume.

The next paper was read by title, and the author presents the following
abstract :

■ >N THE INTRUSIVE ORIGIN OF THE WATCHUNG TRAPS OF NI.W JERSEY.

BY KKANK L. NAmi.v.

[Abstract.]

The study of the Triassic sandstones of New Jersey by the state survey during the
summer of lsss resulted in the discovery or re-discovery of a trap conglomerate on
the northwest border of the formation. This trap conglomerate was found near Rfont-
ville and also at Jacksonville, three miles northeast, in heavy beds. This was at once

imed t" be conclusive proof that the Watch ung trap- were of extrusiv "igin, and

that the pebbles of trap came from these bills.

Much as the late Dr. Cook was opposed to the extrusive theory, he considered this

discovery to be the strongesl positive argument yet advan I by the upholders of the

extrusive origin in support of th<-ir views. Hi- hope was that another source would
I..- found for the trap pebbles, and the question thus be left yet open, at the very least .
Field work during 1*s'" has disclosed the following facts :

1. These trap bowlders have come from the northwest. The reasons for believing
this are that the pebbles are mingled freely with pebbles of gneiss and quartzite
and limestone. These formations ai n the northwest.

2. The traps exposed on Towakhow, Second and First mountains, are amygdaloidal
and fine grained. The trap pebbles in the conglomerate are coarse grained, with ii"
trace of amygdules.

The trap pebbles of the conglomerate have a greal abundance of quartz, while

till. f the Watcbung mountains are almost free IY"in 'mart/.. Nimni'Mi- trap dikes

in the Archean in the northwest, and near by, 'respond with the trap pebbles in

being coarse grained and in having quartz.

I. So tar a- is known, the conglomerates in the vicinity, Cushctunk, New German-
town mountains, and at Pampton Lake, are fr »f trap pebbles. These traps are all

regarded as extrusive by the holders of this extrusive theory. It is held that the
facts above stated thus nullify any conclusions which otherwise would follow from
the presence of a trap conglomerate.

5 The conglomerates which are made up wholly or in part of limestone, trap and
on the northwest border of the Trias, are but slightly conformable t" the gen-
eral Trias. This i ntrary to a statement in 1 1 • * - annual report of the state geologist

for IH8S I mglomeratea have i •'■ the appearance of having been torrential

F. L. NASON — INTRUSIVE ORIGIN OF THE WATCHUNG Til A PS. 563

deposits poured into a lake by streams from the Archean. They could very well have
been formed by wash from the Archean almost independent of streams.

6. The appearance of angular limestone pebbles mingled with well rounded quartz-
ite and gneiss pebbles shows that the conglomerate was rapidly formed, else the lime-
stone pebbles would have been entirely worn away. This conglomerate might well
have been formed during the disturbance caused by the faulting of the rocks and the
outpour of the Triassic traps.

The next paper was —

ON THE PLEISTOCENE FLORA OF CANADA.
BY SIR WM, DAWSON AND D. P. PENHALLOW.

It was read in abstract by Mr. F. D. Adams. The paper is published
among the memoirs, forming pages 311-334.
This was followed by —

THE FIORDS AND GREAT LAKE BASINS OF NORTH AMERICA CONSIDERED
AS EVIDENCE OF PREGLACIAL CONTINENTAL ELEVATION AND OF DE-
PRESSION DURING THE GLACIAL PERIOD.

BY WARREN UPHAM.

From Norway, Denmark, and Iceland we receive the word fiord, meaning a deep,
narrow inlet of the sea, extending in a river-like course many miles into the land.
The continuation of the same valley is occupied by a stream, and there are often trib-
utary fiords and streams entering the main fiord on either side. All the topographic
and geologic characters of fiords prove, as first shown by Dana, that they are partly
submerged channels or valleys which were eroded by rivers when a greater elevation
of the land raised the bottoms of the fiords above the sea level.

The northern Atlantic and arctic shores of North America and Greenland, not less
than the opposite shores of northwestern Europe and Iceland, are indented by very
remarkable and abundant fiords, from Maine and the Gulf of St. Lawrence to Lab-
rador, Hudson strait, the east and north parts of Hudson's bay, and to the most
northern latitudes explored on both coasts of Greenland and in the archipelago be-
tween Baffin bay and the mouth of the Mackenzie. Again, on the western side of our
continent the same evidence of formerly greater elevation of the land and present sub-
mergence is found on the coast of Washington, British Columbia, and Alaska to the
Yukon, in almost countless fiords, and in the channels, straits, and sounds, separated
from the open ocean by high islands, which shelter nearly the entire passage by steam-
boat from Victoria to Sitka.

The fiord best known and most visited by tourists in eastern North America is the
impressively sublime gorge of the Saguenay. The depth of this fiord is stated by Sir
William Dawson to be from 50 to 140 fathoms — that is, 840 feet — below the sea level,
along an extent of about fifty miles from the St. Lawrence to lla-lla bay. while in
some places the bordering cliffs rise abruptly 1,500 feet above the water, making the
whole depth nearly 2,400 feet, with a width that varies from about a mile to one and

504 PROCEEDINGS OF NEW YORK MEETING.

a half miles. It i- thus known that the region of the Saguenay formerly stood at least
about a thousand feet higher than now.

Scarcely less grand is the gorge through which the Hudson pierces the mountain-
Archean 1 « « - 1 1 between Newburgh and Haverstraw; and if there should be a
depression of the land, faster in its rnt<' than the filling of the valley with sediment,
the tidal portion <>f tins river, from Albany t" New fork, would become a fiord.
But the former channel and fiord of the Hudson, which were a continuation of the
present valley but are now submerged beneath the bob outside the NarrowB, arc of
greater interest in our present inquiries, as they Bupply most important testimony
concerning the geologic time and conditions of the erosion of the North American
fiords and the preceding uplift and succeeding subsidence of the northern part of
this continent.

Soundings of the Bea approaches to New York, made in 1842 and 1844 by the United
Sta- I : Survey, were long agosbown by Professor Dana to afford evidence of a
submarine continuation of tin. Hudson river valley; and during the year- 1880 to
1884 minute hydrographic surveys of this part of the submerged Atlantic Blope of
the continent supplemented what was before known, obtaining very significant ob-
servations. A report of this work, written by A. Lindenkohl of the United States
I ast and Geodetic Survey, and read at the meeting of the National Academy of
Sciences April 22, 1885, by J. E. Hilgard, was published in the American Journal
of Science for June of that year. The submarine valley or channel begins to be
noticeable ten miles east by Bouth off Sandy Hook, al a depth of 19 fathom-, and ex-
tends first southerly about ten miles; thence, after bending eastward in the next five
miles, it maintain- a straight course, S. 60° E., to its bar, which is eighty miles from
Sandy Hook. The soundings to the top of the channel'- banks and the submarine
plain on each side along the first ten miles, to the bend, are 18 to 20 fathoms; and
the depth of the channel, from the top to the bottom of it- hank-, increases from one
or two fathoms to 1"> fathoms, or 90 feet. Onward for the next twenty mile- the
depth of the channel continues a1 16 fathoms; hut the soundings to the top of its
banks and the adjacent plain increase to '-'7 fathoms. Along the next ten miles the
channel decreases in depth to 11 fathoms, in ten miles more to only 7 fathoms, and
then in ten miles t,> 5 fathoms. At five miles farther, or seventy-five mile- from

Sandy Hook, it- depth i- two fathom-, and it eea-e- within the nexl five mile-.

Through the forty miles in which the depth of the channel decreases, the soundings
to the top of its hank- increase from 27 to 18 fathom-, or 258 f<

The average -lope of the hank- i- one degree, and the width of the included chan-
nel from three-quarters of a mile to one mile ; but in the bend the -lope i- increased

to three degrees and the width contracted to an eighth of a mile. S| imens of the

bottom brought up by the lead from the bed and hank- of the channel are sandy

clay, evidently the continuation, as believed by Mr. Lindenkohl, ol the Tertiary

indy clay strata " found occupying the southeastern part of New Jersey by the

logical survey of that -tnic. The adjacent plain differs from the channel in being

overspread with -and and gravel, which appear to be of Quaternary age and th n

tinuation of the expanse of modified drift that form- the Bouth side of Long island,
Bloping down from the front of the terminal moraine.

ond the bar of fine sand which terminate, thi* channel, a submarine fiord Is
found in the line of it- continuation, extending about twenty-five miles, with a width

of three miles, to th Ige of the steep continental Blope at a distance of about one

hundred and ii\e mile from Sandy Hook. The adjacenl flal sen bottom descends

W. UPHAM — FIORDS AND LAKE BASINS. 505

along those twenty-five miles from 50 to 100 fathoms. The bed of the fiord, as de-
scribed by Lindenkohl, commences with a depth of only about 10 fathoms below the
general plain, or 60 fathoms below the sea level ; but the soundings in the fiord in-
crease to 200 fathoms within the first mile, and its deepest sounding, 474 fathoms, is
close to its outlet. "This outlet to the ocean," writes Lindenkohl, "is in the shape
of a bar with a depth of about two hundred fathoms. For half its length, from its
middle to the bar, this ravine maintains a vertical depth of more than two thousand
feet, measuring from the top of its banks ; these banks have a nearly uniform slope
of about 14°. It remains to be stated that the bottom and the sides of the ravine are
composed of a green sandy mud, and that the adjacent flats, unlike those of the sub-
merged channel, show the same material."

This fiord under the sea demonstrates that the border of the continent in the vicinity
of New York has been uplifted 2,800 feet higher than now, while a large stream here
flowed down from the equally or perhaps more uplifted basin of the Hudson, proving
that the elevation affected a very extensive area. The date of this uplift is shown to
have been after the deposition of the Tertiary beds of New Jersey, in which the
channel and fiord are eroded ; and the length of time during which the land stood at
this height was manifestly short, geologically speaking, else the fiord would be much
longer, occupying the place of the comparatively shallow channel.

When subsidence of the country ensued, a very massive bar was formed by coast-
wise wash across the mouth of the Hudson fiord, attaining a height of 1,000 feet above
its bottom, and the crest of this bar is now about 1,200 feet below the sea level. A
later stage in the subsidence, when the land was only about 200 feet above its present
height, is marked by the sand bar at the end of the submarine channel. From then
to the time of formation of the present bar the depression of the land seems to have
been too rapid to permit such accumulation ; but since the channel southeast of Sandy
Hook was submerged, a bar rising from 19 fathoms to 4 fathoms below present mean
sea level has been built up. By Mr. Lindenkohls computation, based on Professor
Cook's estimate that the present rate of subsidence of the coast of New Jersey is about
two feet in a hundred years, this bar represents a period of 4,500 years ; but the aver-
age subsidence may have been slower, allowing a considerably longer time.

Combining this testimony of oscillations of the land with the records of the Glacial
period, whose terminal moraine, at the southern limit of the till and of glacial stri»
and glacially transported bowlders, forms the range of hills called the backbone of
Long island and thence reaches westward from the Narrows across Staten island and
northern New Jersey, we find their relationship to be as follows: Shortly before the
Ice age this area was greatly uplifted, holding an altitude a half mile or more above
its present height long enough for the Hudson to cut its now submerged fiord, twenty-
five miles long and three miles wide, in easily eroded sandy clays. This elevation into
the cold upper strata of the atmosphere may well have been the direct cause of the ac-
cumulation of the Quaternary ice-sheet, which covered the northern half of the conti-
nent, forming the terminal moraines and other drift deposits. Beneath the ice-sheet,
however, the land was depressed until, when the ice finally melted away, much of the
coast stood lower than now, as shown by fossiliferous marine beds overlying the glacial
drift in northern New England, New Brunswick, the valley of the St. Lawrence,
about Hudson's bay, and in Labrador and Greenland. The amount of this depression
increases from a few feet near Boston and Gloucester, Massachusetts, to .V_'(i feet at
Montreal, and 1,000 to 2,000 feet in Greenland and Grinnell Land. Though it v
probably induced by the pressure of the ice-weight, it does not appear to have been

LXXV— Bri.i,. Gf...t,. Soc. Am., Vol. 1, 1889.

566 PROCEEDINGS OF XKW YORK MEETING.

even approximately proportionate, upon certain parta of it- area, to the thickness
the ice accumulation. The sea, after the retreat of the ice, extended over the basin of
Lake Cham plain and far up the St. Lawrence and * »t t n w.i valleys, but no Quater.
nary marine beds are found about Lake Ontario nor thence westward. In 1 1 » « - latitude
of New York, channels of southward drainage from the terminal moraines <>l" Long
island, Martha's Vineyard, Nantuckel and Cape Cod, crossing their frontal plains
modified drift and continuing beneath the -e:i. Bhow that 1 1 1 i - part of the coast was
higher when these moraines were fprmed than now; and, as no post-glacial marine
beds are found there, we may infer that no subsequent sinking bas ;it any time carried
tlii.- tract below its present level. It therefore seems probable that while- the ice sheet
was retreating from it- terminal moraine on Staten island, past the Catskills and along
the Hudson and Champlain valley, the alevation ot the coastal plain outside the Nar-
rows, doubtless -till retaining a hundred feet or more of it- for rly very great alti-
tude above the sea, and the contemporaneous depression of the region toward the north,
known to have been more than five hundred feet below the present sea level at Mon-
treal, caused the Hudson valley from Manhattan island northward to 1" cupied by

a lake, held in by the northern barrier of the receding ice-sheet, and outflowing to the
sea over the now submerged plain off Sandy Hook. Since the departure of the ice, a
see-saw movement, further depressing the mouth of the Hudson and again uplifting
the country northward, has determined the present courses of drainage.

Returning to the fiord of the Saguenay, cut in the very hard Laurentian gneiss and
granite, and comparing it with the shorter submerged fiord of tin' Hudson, cut in soft

Tertiary (days, it i- obvious that a much longer time was required for tl rosion of

the Saguenay gorge and the similar fiords of all the coast from Maine to Greenland,
and also from the Columbia to Alaska; but still thi> work was not geologically very
long, else these valley.- would have become widened, being bordered by gentle slopes
instead of Bteep fiord walls. Professor Hitchcock has called attention to the general
absence of Tertiary formation- alone; these northern shores of our continenl as proof
that the land was higher than now throughout the whole Tertiary era. N'o coastal
Pliocene formations are known north of the Carolina-. Thence to the Arctic ocean
the present land surface seems to have been nowhere submerged during the Pliocene
period : but, on the contrary, evidence of great elevation is afforded by the stream-
eroded indentations of Pamlico and Albemarle Bounds and Chesapeake and Delaware
hay-, while the vastly older northern coasts are sharply incised by the deep but nar-
row fiords. This erosion was probably effected during a period of extraordinary ele-
vation, when the northern part of this continent was uplifted as a plateau much above

previous or present height ; and this uplift seems to have occurred earlier and to
have lasted longer in far northern latitude.- than in the vicinity of New York-. The
Hudson fiord indicates that it culminated near the close of the Pliocene period, initiat-
ing the Quaternary glaciation.

In the interior of the continent, evidence of -imilar preglacial elevation and of de-
pression during the Glacial period is afforded by the basins of the ureal Laurentian

lake- The origin and history of th basins have been well studied by Newberry,

( 'lay pole, Spencer, Drum mond, and other-. In the light of their investigations let us
briefly the geologic records of tl scillatione of this area :

Tie- very ureat disturbances of the region on the west in elevation of the Cordille-
ran mountain i m<e the Cretaceous period, make it impossible to identify

there the cour f the larger tributaries to the mediterranean I which

Btretched from the Gulf of Mexico to the latitude of Athabasca and Great Slave

J. HALL — THE GENUS SPIRIFERA. 567

lakes ; but on the eastern half of the continent the principal drainage system, carrying
its vast freight of detritus west to the Cretaceous ocean, is probably marked by the
chain of great lakes from Ontario to Superior, the west end of which is close to the
east border of the Cretaceous belt. At that time and afterward much of this eastern
land area was elevated at least several hundred feet above its present level, so that
streams flowing where these great lakes now are, eroded their basins, then lying
wholly above the sea level and sloping westward. It seems possible also that other
great tributaries may have flowed west and south into this Cretaceous sea, bringing
sediments eroded from the areas of Hudson's bay, Lake Athabasca, and Great Slave
and Great Bear lakes. Amid the subsequent changes of level which have perma-
nently uplifted the Cretaceous sea-bottom in the center of the continent, and have
uplifted and afterward depressed our northern coasts, both on the Atlantic and the
Pacific, the writer. believes that the basins of the Laurentian lakes, while still contin-
uous areas of valley erosion, were raised with the country east and west to a great
altitude for a short time at the end of the Pliocene period, as shown by deep stream-
courses enveloped by the drift deposits, but that in the Quaternary depression, by dif-
ferential subsidence, these basins became divided from each other, their bottoms,
excepting that of Lake Erie, sinking beneath the level of the sea. The avenue of
outflow from them has been turned to the northeast, forming the Eiver St. Lawrence,
in the Glacial period. President Chamberlin believes that much subsidence of the
beds of these lakes probably is attributable to the weight of the ice-sheet. The post-
glacial re-elevation, which has produced the northward ascent of the beaches of the
glacial Lake Agassiz and of the contemporaneous higher stages of the Laurentian
lakes, has failed to raise these lake beds, as likewise the bottoms of the fiords, to the
present sea level.

The next paper was presented in abstract only, and follows in brief
synopsis :

ON THE GENUS SPIRIFERA, AND ITS INTERRELATIONS WITH THE GENERA
SPIRIFERINA, SYRIXGOTHYRIS, CYRTIA AND CYRTINA.

BY JAMES HALL.

[Synopsis.]

1. Great development of Spiriferg, in American Paleozoic.

2. Previous classification of species.

3. External ornamentation as a basis of classification.

NORMAL FORMS.

(.4) radiata
(B) Ifime/losa

(C)fimbriafa ] j- Begin in the Niagara.

fimbriaia-plicata j- reticularia. McCoy.

" undid ata j J

ABERRANT FORMS.

(D) Icevls. Begins in the Corniferous.
Ambocoelia differs internally.

568 PROCEEDINGS OF MEW YORK MEETING.

!/■;. medio-plieata. Begins in the Oriskany.

n) Forms of sub-circular or elongate outline — S. hungcrfordi.
Forms in which plications are few and strong -S. keokuk.
Forms in which plications are in fascich S. camerata.

I S ringothyris group. Begins in the Corniferous.

The radiata, fimbriate, and medio-plicaia are without «.——•• 1 1 1 i : 1 1 variation

in spiriferoid character.
Icevis: slightly variable in development of dental lamellae.
lamtllosa: septate or non-septate. The septate group begins in the
Niagara, is continued through the lower Helderberg, Cornifer
Hamilton and Kinderhook ; the Bhell remaining impunctate
Results in Spiriferina.
Where does punctation begin ?
medio-la via : Gradual dr\ elopmenl of apical callosity, Syringothyria tube,
high area, etc.

Homologous structure in Cyrtina.
Incipient punctation in Syringothyria.
Cyrtina: In external expression usually in harmony with medvo-lcevis.
> Like Cyrtina on outside ; differs from Spirifera only i:: the de-

velopment of the dental lamella).

The next paper was entitled :

<»N ill i : METAMORPHIC ROCKS OF SOUTHEASTERN NEW YORK.

nv B\ .1. li. MERRILL.

Ii led to a discussion in which ('. If. Van Hise, B. K. Emerson, C. II.
Hitchcock, and J. E. Wolff took part.
The remaining paper was read by title, in the absence of the author:

ON POT-HOLES NORTH OF LAKE SUPERIOR UNCONNECTED WITH EXISTING

STREAMS.

BY PETER MCE ELL \ K. I'. <;. B.

In is;i inv brother Donald McKellar discovered a large pot-hole in hornblende
rock about I' miles back from McKellar harbor, northeast of the Slate islands, on
ilP- north shore of Lake Superior.

I examined the locality and found aboul fifty similar holes, with diameters varj ing

from :i couple of feet up to i 'e than thirty feet. Some are quite round, Bmooth, and

well denned ; others are oblong, - f which appear to result from coalescence of

two or more holes. These holes occur on i li'- east side of a steep mountain, and show

on tin' different ledges from the bottom up t" within a few feel of the summit. The

moil ii i ain ~id'- •■!' many of the boles Btands up above the front Bide, in Borne

• much as thirty feet or more. In general these holes are filled up, or nearly

with such materials n- bowlders, gravel, sand, black mink and water, but Borne are

emptj down for many feet. Their depths are unknown, as in uo case has tli*' bottom

n reached or exposed, although in several instanci - a pole has been Bboved

down in the j ••■:it \- l"'tt.>nj for several feet,

P. MCKELLAR — POT-HOLES NORTH OF LAKE SUPERIOR. 569

The original pot-hole area was, most probably, much larger than it is now, as much
erosion of the mountain and vicinity seems to have taken place since the formation of
these holes. An area 200 by 400 feet would, I think, cover what now remains of the
perforated surface. Further examination may discover many more pot-holes here, as
portions are under cover of drift, alluvium and vegetable matter.

The mountain is about 200 feet high, and at its base on the southeast side is a small
lake or pond ten or twelve acres in extent. When viewing the situation I was im-
pressed with the idea that these pot-holes are the work of a great stream, and that
this little lake is the chief pot-hole or pool into which the mighty fall of water
plunged; these seem the only traces left of that stream of the lone; past ages. L
named the mountain Pot-hole mountain, and the lake Pot-hole lake

In the following notes of a number of the pot-holes, the measurements are approxi-
mate estimates made on the ground and not exact measurements.

No. 1. The pot-hole is at an elevation of 150 to 200 feet above, and lies 100 to 150
feet to the west of Pot-hole lake. It is double; shorter diameter, 16 feet; longer,
30 feet. Wall, smooth and vertical, rises above the black muck filling, to the west
20 feet, to the north 6 feet, and to the east 2 feet.

No. 2. The pot-hole is 6 feet in diameter, lies 40 feet to the eastward of and 8 feet
below no. 1. The western wall is elevated 4 feet above the eastern.

No. 3. 5 by 6 feet in diameter, lies 15 feet north of no. 1. The back or west-
ern wall rises above the filling and the front portion of wall about 12 feet.

No. 4. 4 by 5 feet in diameter ; lies from no. 1, N. 16° E. 120 feet. The western
wall rises 30 feet above the filling and the front.

No. 5. 6 feet lower than no. 4. It is sub-triangular, with the sides 10 feet each.
The wall rises to the north 10 to 20 feet, with an inclination of 85° ; to the south-
west 25 feet ; to the southeast 6 feet ; and to the east 3 feet.

No. 6. 5 feet lower and 8 feet to the east of no. 5. The wall rises above filling,
to the north 1J feet, to the east 1 foot, to the south 4 feet, and to the west 5 feet.

No. 7. 5 feet above and 3 feet northeast of no. 5. It is round and smooth, filled
with black muck.

No. 8. 7 feet to the northeast of and 10 feet lower than no. 5. It is 17 feet in
diameter, with the wall rising to the northeast 3 feet ; to the north 10 feet; to the
northwest 20 feet ; to the southwest 7 feet ; and to the east 1 foot.

No. 9. 4 feet lower than and 10 feet east-northea>t of no. 8. Its diameter is 8 by 10
feet, increasing in size downwards. The wall rises about 5 feet above the earthy
filling all around.

No. 10. 20 by 60 feet in diameter, filled with bowlders, earth, etc.

No. 11. 4 feet in diameter, with a portion of the wall rising 10 feet.

No. 12. 6 by 10 feet in diameter. The wall rise.-> to the west 16 feet; to the north
and the south about 8 feet. There are two small pot-holes in the top of the wall, with
diameters of 2 and 3 feet respectively.

No. 13. 6 feet in diameter. The wall is smooth and rises in places to the heighl of
about 8 feet ; another hole 3 feet in diameter is distant 2 feet to the ea^t and is 6 feet
lower.

No. 14. 12 feet northeast of and 8 feet lower than no. 13.

No. 15. 6 feet in diameter. Lies 8 feet to the southeast of and is 10 feet lower than
no. 8. The wall is low to the east, 18 feet high to the south and the southwest, and
11 feet to the northward.

No. 16. 12 feet east of and 8 feet lower than no. 15.

570 PROCEEDINGS OF NEW YORK MEETING.

17. 16 by 25 feet in diameter. The wall between it and no. 13 stands up 1 feel
above the filling, with a thickness of only '2 feet.

18. <i by 1<> feet in diameter ; 2t5 feet southwest of and 10 feet higher than no. 5.
\ 19. The west wall rises 30 feet.

20. 5 feet in diameter, and it- wall rises 3 to I

The Twin pot-holes are situated near the edge of :i cliff of rock and about 20 to :;<>

feet below the- summit of the mountain, and are im diatcly west of and about 60

>ve pot-hole no. 17 in thi ;ml; list. The two holes art round and smooth

and 6 to 7 feel each in diameter. In going down they join :it a depth of 1<» to r_!
feet, and within :i yard or so of the earthy bottom. About the point where the two
join, the one on the south side has broken an opening "_' to 3 feet by I to •"> feet in
diameter out into the face of the steep cliff. I descended to the bottom with a sharp-
ened pole and forced it down into the soft peaty bottom several feet without reaching
the .-olid rock.

Pot-hole mountain is composed of a dark green hornblende rock, with a small
percentage of greenish white feldspar. It is hard and tough, and shows a fibrous
structure It form- one of c 1 i «- strata of the green Hurouian schists which occupy the
locality. These strata dip to the N. N. W. at a high angle.

The surface of the surrounding country is rough and rocky by reason of the numer-
ous coalescing valley.-, with oblong hills often steep and bare, and rising 50 to over
200 feet above them. The general level of the bottoms of these valleys rises irregularly
ha<d< from Lak>- Superior, and gains an elevation of probably 300 feet at Pot-hole
lake. Pot-hole mountain is one of the highest knobs in the locality. It is surrounded

by a deep valley near by, and in the distance by similar knobs and vallej -. es| ially

toward- the northwestward, the direction from which the stream that produced the pot-
hide- seems to have flowed. When this stream was in action the valleys to the northwest-
ward must have been filled with rock, earth, or ice to carry the stream. Since then
the locality has heen eroded and a vast amount of material Bwept away. I n oik
horizontal glacial grooves may be -ecu on a portion of the elevated, vertical wall
.if the pot-hole. The action of the water is evident everywhere. 'I show

at higher elevation- than Pot-hole mountain, in the neighborhood and along Lake
Superior.

[n conclusion, J would Btate that it seems to me that the current- that produced
these pot-holes existed prior to the ChampTain or even the close of the Drift epoch, if
not pri<>r to the beginning of the latter.

The retiring President, Professor .lame- Hall, gave a farewell addr<
The Society then adjourned to meet al [udianapolis on Tuesday, August 19,
L890, al Mi A. M.

CONSTITUTION AND BY-LAWS OF THE GEOLOGICAL

SOCIETY OF AMERICA.

CONSTITUTION.

Preamble.

The Fellows of The Geological Society of America, organized under the
provisions of the Constitution approved at Cleveland, Ohio, August 15, 1888,
and adopted at Ithaca, New York, December 27, 1888, hereby ordain the
following revised Constitution :

ARTICLE L— Name.

This Society shall be known as The Geological Society of America.

ARTICLE II. -Object.

The object of this Society shall be the promotion of the Science of Geology
in North America.

ARTICLE III.— Membership.

Section 1. The Society shall be composed of .Fellows, Correspondents,
and Patrons.

Sec. 2. Fellows shall be persons who are engaged in geological work or in
teaching geology, and resident in North America.

Fellows admitted without election, under the Provisional Constitution,
shall be designated as Original Fellows on all lists or catalogues of the
Society.

Sec. 3. Correspondents shall be persons distinguished for their attain-
ments in geological science, and not resident in North America.

Sec. 4. Patrons shall be persons who have bestowed important favors
upon the Society.

Sec. 5. Fellows alone shall be entitled to vote or hold office in the Society.

ARTICLE IV.— Officers.

Sec. 1. The Officers of the Society shall consist, of a President, First and

Second Vice-Presidents, a Secretary, a Treasurer, and six Councilors.

These officers shall constitute an Executive Committee, which shall be

called the Council.

(571)

572 PROCEEDINGS OF MEW YORK MEETING.

Sec. 2. The President shall discharge the usual duliesofa presiding officer
at all meetings of the Society and of the < louncil. He shall take cognizance
of the acts of the Society and of its officers, and cause the provisions of the
Constitution and By-Laws to be faithfully carried into effect.

Sec. 3. The First Vice-President -hall assume the duties of President in
case of the absence or disability of the Latter, The Second Vice-President
-hall assume the duties of President in case of the absence or disability of
l.uth the Presidenl and First Vice-President.

Sec. 1. The Secretary -hall keep the records of the proceedings of the
Society, and a complete list of the Fellows, with the date- of their flection
and disconnection with the Society. lie shall also he the Secretary of the

( 'olllicil.

The Secretary shall eo-operate with the President in attention to the
ordinary affairs of the Society. He shall attend to the preparation, print-
ing, and mailing of circulars, blanks, and notifications of elections and
meetings. He shall superintend other printing ordered by the Society or
by the President, and shall have charge of its distribution under the direc-
tion of the Council.

The Secretary, unless other provision he made, shall also act a- Editor of
the publications of the Society, and as Librarian and Custodian id' the prop-
erty.

Si c. 5. The Treasurer shall have the custody of all funds of the Society.
He shall keep an account of receipt- and disbursements in detail, and this
-hull he audited a- hereinafter provided.

Sec. 6. The Society may elect an Editor, to supervise all matters con-
nected with the publication of the transactions of the Society under the direc-
tion id' th<' Council, ami to perform the duties of Librarian until such time
as, in tl pit don of the Council, the Society should make that an independ-
ent office.

Sec. 7. The ( buncil is clothed with executive authority, and with the legis-
lative powers of the Society in the intervals between it- meetings; hut no
extraordinary act of the Council shall remain in force beyond the next fol-
lowing stated meeting, withoul ratification by the Society. Tin' Council
dial I have control of the publications of the Society, ler provisions of the

By-Laws and of resolutions from time to time adopted. They shall receive

nomination- for Fellows, and on approval by them' -hall suhniit such nomi-
nations to the Society for action. They shall have power to fill vacancies

ad 'mil rim in any of the offices of the Society.

Sec, -. Terms of Office. — The President ami Vice-Presidents shall he
elected annually, ami -hall not he eligible to re-election more than once
until after an interval of three years alter retiring from office.

CONSTITUTION AND BY-LAWS. 573

The Secretary and Editor shall be eligible to re-election without limita-
tion.

The term of office of the Councilors shall be three years ; and these officers
shall be so grouped that two shall be elected and two retire each year.
Councilors retired shall not be re-eligible till after the expiration of a year.

ARTICLE V. — Voting and Elections.

Sec. 1. All elections shall be by ballot. To elect a Fellow, Correspond-
ent, or Patron, or to impose any special tax shall require the assent of nine-
tenths of all Fellows voting.

Sec. 2. Voting by letter may be allowed.

Sec. 3. Election of Fellows. — Nominations for fellowship may be made by
two Fellows, according to a form to be provided by the Council. One of
these Fellows must be personally acquainted with the nominee and his quali-
fications for membership. The Council will submit the nominations received
by them, if approved, to a vote of the Society in the manner provided in
the By-Laws. The result may be announced at any stated meeting ; after
which notices shall be sent out to Fellows elect.

Sec. 4. Election of Officers. — Nominations for office shall be made by the
Council. The nominations shall be submitted to a vote of the Society in the
same manner as nominations for fellowship. The results shall be announced
at the Annual Meeting ; and the officers thus elected shall enter upon duty
at the adjournment of the meeting.

ARTICLE VI.— Meetings.

Sec. 1. The Society shall hold at least two stated meetings a year — a
Summer Meeting, at the same locality and during the same week as the an-
nual meeting of the American Association for the Advancement of Science,
and a Winter Meeting. The date and place of the Winter Meeting shall be
fixed by the Council, and announced by circular each year within a month
after the adjournment of the Summer Meeting. The programme of each
Meeting shall be determined by the Council, and announced beforehand,
in its general features. The details of the daily sessions shall also be ar-
ranged by the Council.

Sec. 2. The Winter Meeting shall be regarded as the Annual Meeting.
At this, elections of Officers shall be declared, and the officers elect shall
enter upon duty at the adjournment of the Meeting.

Sec. 3. Special Meetings may be called by the Council, and must be
called upon the written request of twenty Fellows.

LXXVI— But.r.. Geol. Soc. Ah., Vor, 1, 18S0.

."., 1 PROI EEDINGS "I NEW FORK Ml ETING.

Se< . 1. Stated Meetings of th Council shall be held coincidently with the
Stated Meetings of the Society. Special meetings may be called by the Presi-
dent at Buch times a- he may deem accessary.

Sec. 5. Quorum. — At meetings of the Society a majority of those registered
in attendance -hull constitute a quorum. Five shall constitute a quorum of
the ( Iouncil.

ARTICLE VII— Pi i.i n LTION.

The serial publications of the Society shall he under the immediate con-
trol of the ( Iouncil.

ARTICLE VIIL— Amendm] nts.

Sec. 1. This Constitution may be amended al any annual meeting by a
three-fourths vote of all the Fellows, provided thai the proposed amendment
-hall have been submitted in print to all Fellows at Least three months pre-
vious to the meeting.

Sec. 2. By-Laws may be made or amended by a majority vote of the Fel-
lows present and voting at any annual meeting, provided that printed notice
of the proposed amendment or By-Law shall have been given to all Fellows
at least three months before the meeting.

BT-LA WS.

CHAPTER I— Of Membership.

Sec. 1. No person -hall he accepted as a Fellow unless he pay his initia-
tion fee, and the dues for the year, within three month- after ratification of
his election. The initiation fee shall be ten (10) dollars and the annual dues
ten i in i dollars, the latter payable on or before the annual meeting, in ad-
vance; but a single prepayment of one hundred i LOO) dollar- shall be ac-
cepted as commutation for life.

Sec. 2. Thesums paid in commutation of dues shall be invested and the
interesl used for ordinary purposes of the Society during the payer's life,
but after hi- death the sum shall be covered into the Publication Fund.

Sec. 3. An arrearage in payment of annual due- -hall deprives Fellow
of the privilege of taking part in the manage ul of the Society, and of re-
ceiving the publications of the Society. An arrearage continuing over two
yean .-hall be construed as notification of withdrawal.

-n . I. Any person eligible under Article III of the Constitution may be
elected Patron upon the payment of one thousand I 1,000) dollar- to the Pub-
lication Fund of the Society.

CONSTITUTION AND BY-LAWS. .)75

CHAPTER II.— Of Officials.

Sec. 1. The President shall countersign, if he approves, all duly author-
ized accounts and orders drawn on the Treasurer for the disbursement of
money.

Sec. 2. The Secretary, until otherwise ordered by the Society, shall perform
the duties of Editor, Librarian, and Custodian of the property of the Society.

Sec. 3. The Society may elect an Assistant Secretary.

Sec. 4. The Treasurer shall give bonds, with two good sureties approved
by the Council, in the sum of five thousand dollars, for the faithful and
honest performance of his duties, and the safe-keeping of the funds of the
Society. He may deposit the funds in bank at his discretion, but shall not
invest them without authority of the Council. His accounts shall be bal-
anced as on the thirtieth day of November of each year.

Sec. 5. In the selection of Councilors the various sections of North America
shall be represented as far as practicable.

Sec. 6. The minutes of the proceedings of the Council shall be subject to
call by the Society.

CHAPTER III— Of Election of Members.

Sec. 1. Nominations for fellowship may be proposed at any time on blanks
to be supplied by the Secretary.

Sec. 2. The form for the nomination of Fellows shall be as follows :

In accordance with his desire, we respectfully nominate for Fellow of the Geologi-
cal Society of America :

(Full name)

(Address)

(Occupation)

(Branch of Geology now engaged in, work already done, and publications made)

(Degrees, if any)

(Signed by at least two fellows)

The form when filled is to be transmitted to the Secretary.

Sec. 3. The Secretary shall bring all nominations before the Council, at
either the Winter or Summer Meeting of the Society, and the Council shall
signify its approval or disapproval of each.

Sec. 4. At least a month before one of the stated meetings of the Society,
the Secretary shall mail a printed list of all approved nominees to each Fellow,

576 PROCEEDINGS OF NEW YORK MEETING.

accompanied by such information as may be necessary for intelligent voting.
But an informal li>t of the candidates Bhall be sent to each fellow at Leasl
two weeks prior t<» distribution of the ballots.

>i i . 5. The Fellows receiving the list will signify their approval or dis-
approval of each nominee, and return the lists to the Secretary.

Sec. 6. At the next stated meeting of the Council the Secretary shall pre-
sent the lists, and the Council shall canvass the returns.

Se< . 7. The Council, by unanimous vote of the members in attendance,
may still exercise the power of rejection of any nominee whom new informa-
tion shows to be unsuitable for fellowship.

Sec. 8. At the next stated meeting of the Society the Council shall de
clare the results.

Sec. 9. Correspondents and Patrons shall he nominated by the Council,
and -hall he elected in the same manner as Fellows.

CHAPTER IV.— Of Election of Officers.

Sec. 1. The Council shall designate three candidates for cadi office.
Sec. 2. The form for the nomination and election of officers, unless other-
wise provided by the Council, shall be as follows:

The Council nominates for Officers of the Geological Society of America, for the
ensuing year, the following persons :
(Tin- voter will indicate In- preference out of each of the Bets of names below by
sing the two other names in each set, or will substitute the name of his choice.)

fl.

For President, -J 2.

[a-

fl-
I
For Pi I \ ice- President, ; 2.

( '■

Fur Second \ ice-President, | 2.

18.
1.

rotary, '-'■

For Treasurer, \ '-'•

I
8

CONSTITUTION AND BY-LAWS. 577

For Councilor, -J 2.

I
13.

fl-

For Councilor, \ 2.

I 3.

The Secretary shall mail a copy of this ballot to each Fellow, who after
making up the list will return it to the Secretary.

Sec. 3. At the winter meeting of the Council, the Secretary shall bring the
returns of ballots before the Council for canvass, and during the winter
meeting of the Society the Council shall declare the results.

Sec. 4. In case a majority of all the ballots shall not have been cast for
any candidate for any office, the Society shall by ballot at such winter meet-
ing proceed to make an election for such office from the two candidates hav-
ing the highest number of votes.

CHAPTER V.— Of Financial Methods.

Sec. 1. No pecuniary obligation shall be contracted without express sanc-
tion of the Society or the Council. But it is to be understood that all ordi-
nary, incidental and running expenses have the permanent sanction of the
Society, without special action.

Sec. 2. The creditor of the Society must present to the Treasurer a fully
itemized bill, certified by the official ordering it, and approved by the Presi-
dent. The Treasurer shall then pay the amount out of any funds not other-
wise appropriated, and the receipted bill shall be held as his voucher.

Sec. 3. At each annual meeting, the President shall call upon the Society
to choose two Fellows, not members of the Council, to whom shall be referred
the books of the Treasurer, duly posted aud balanced to the close of
November thirtieth, as specified in the By-Laws, Chapter II, Section 4.
The Auditors shall examine the accounts and vouchers of the Treasurer, and
any member or members of the Council may be present during the exami-
nation. The report of the Auditors shall be rendered to the Society before
the adjournment of the meeting, and the Society shall take appropriate
action.

CHAPTER VI— Of Publications.

Sec. 1. The Publications are in charge of the Council and under its con-
trol.

Sec. 2. One copy of each publication shall be sent to each Fellow, Cor-
respondent, and Patron, and each author shall receive thirty (30) copies of
his memoir.

578 PROCEEDINGS OF SEW YORK MEETING

CHAPTEB VII.— Of phe Pubi u ltion Fund.

Sec. I. The Publication Fund shall consist of moneys paid by the general
public for publications of the S iciety, of donations made in aid of publica-
tion, and of the suras paid in commutation of dues, according to the By-
Laws, < !hapter I. Section *_'.

Sec. 2. Donors to this fund, not Fellowa of the Society, in the sum of two
hundred dollars, shall be entitled without charge, to the publications subs
quently appearing.

CHAPTER VIII.— Of Order of Business.

Sec. 1. The order of Business at Annunl Meetings shall be as follows
(1) Call to order by the Presiding Officer.

2 Introductory ceremonii

3 Statements by the President.
I Report of the Council.

Report of the Treasurer, and appointment of the Auditing Com-
mittee.

6) Declaration of the results of the ballot for officers of the next

ensuing Administration.

7) Declaration of the results of the ballot for uew Fellows.

(8 1 Announcement of the hour ami place for the Address of the last

ex-President.

9 Necrological uotices.

I 10) Miscellaneous announcements.

(11) Business motions and resolutions and disposal thereof.

(12) Reports of committees and disposal thereof.
I 13) Miscellaneous motions and resolutions.

Ml Presentation of memoirs.

Si i . '_'. At an adjourned session, th 'der shall be resumed at the place

reached on the previous adjournment, but new announcements, motions, and
ilutions will be in order before the resumption of the business pending at
the adjournment of the last preceding session.

3ec. 3. At the Sumnu r .1/' eting the items of business under numbers I),

shall be omitted.
Sec. I. At a,iiy Special Meeting the Order of Business Bhall be (1 .
.7 . 10), followed by the special business for which the meeting was

.•all. d.

LIST OK

OFFICERS AND FELLOWS OF THE GEOLOGICAL SOCIETY

OF AMERICA.

OFFICERS FOR 1889.

James Hall, President.

James D. Dana, \ 17. d . 7 .

Alexander Winchell, J

John J. Stevenson, Secretary.

Henry S. Williams, Treasurer.

John S. Newberry, ")

J. W. Powell, > Members-at-large of the Council.

Chas. H. Hitchcock, »

FELLOWS.
Original Fellows.

1. Charles C. Abbott, M. D., Trenton, N. J.

2. Charles A. Ashburner, M. S., C. E., Pittsburgh, Pa. (Died December 24,

1889.)

3. George. F. Becker, Ph. D., San Francisco, Cala. ; U. S. Geological Survey.

4. John C. Branner, Ph.D., Little Rock, Ark.; State Geologist of Arkansas.

5. Garland C. Broadhead, Columbia, Mo. ; Professor of Geology in the Uni-

versity of Missouri.

6. Samuel Calvin, Iowa City, Iowa; Professor of Geology and Zoology in the

State University of Iowa.

7. Thomas C. Chambkrlin, LL. D., Madison, Wis.; President of the Univer-

sity of "Wisconsin.

8. J. H. Chapin, Ph.D., Meriden, Conn. ; Professor in St. Lawrence University.

9. AVn.LTAM B. Clark, Ph. D., Baltimore. Md. ; Instructor in Geology in Johns

Hopkins University.

10. Edward W. Claypolk. D. Sc, Akron, Ohio; Professor of Geology in Buchtel

College.

11. John Collett, M. D., Indianapolis, I ml. ; State Geologist of Indiana.

12. Theodore B. Comstock, Austin, Tex ; Geological Survey of Texas.

13. George H. Cook, Ph.D., LL. D., State Geologist ; Professor of Geology in

Pvutgers College. (Died September '-'2, 18890

14. Edward D. Cope, Ph. D., 2102 Pine St., Philadelphia; Professor "I' Geology

in the University of Pennsylvania.

LXXVH— Bum.. Geol. Soc. Am., Vol. 1,1889. '79)

580 PRO( EEDINGS OF NEW YORK MEETING.

15. Fran< i- W. Cum. in. B. S., Topekn, Kansas; Pr< Df Geology and Natural

History in Washburne Coll(

16. Albert R. Crandall, A. M., Lexington, Kentucky; Professor of Geology in

\ e • icultural and Mechanical C<>llfu'' of Kentucky.

17. \\ ii.i.iam O. Crosby, B. S., Boston Society of Natural History. Boston, Mass. ;

Assistant Professor of Mineralogy and Lithology in Massachusetts [nstitute
of Technology.
is. Malcolm II. Cri mp, Bowling (Jreen, Kentucky : Profi — r of Natural Science
in ( >gden College.

19. Henry P. Cushing, M. S., 786 Prospect St., Cleveland, Ohio.

20. Jambs D. Dana, LL. D., New Haven, Conn. ; Professor of Geology in rale

University.

21. Nelsom II. Darton, United States Geological Survey, Washington, D. C.

22. William M. Davis, Cambridge, Mass.; Professor of Physical Geography in

Harvard University.
•r,. JOSEPH S. DiLLER, I'.. S., United States Geological Survey. Washington, D. ('.
•_M. William B. Dwight, M. A., Ph. B., Poughkeepsie, N. Y. ; Professor of

Natural History in Vassar College.

25. George H. Eldridgk, A. B., United States Geological Survey, Washington,

D. C.

26. Benjamin K. Emerson, Ph.D., Amherst, Mass.; Professor of Geology in

Amherst College.

27. Samuel P. Emmons, A. M., E. M., CTnited States Geological Survey. Washing-

ton, D. C.

28. Herman L. Fairchild, I'.. S., Rochester, N. Y. ; Professor of Geology and

Natural History in University of Rochester.

29. Albert E. Foots, M. D., 1223 Belmont Ave.. Philadelphia, Pa

30. P. M w F08HAY, A. B., Beaver Falls, Pa.

31. Psrsifor Frazer, D. Sc, 1012 Drexel Building, Philadelphia, Pa. ; Professor

of Chemistry in Franklin Institute.
:;•_• Homer T. Pi ller, Ph. D., Worcester, Ma-.; Professor of Geology in \V<>r<

ter Polytechnic Institute.
:;::. Grove K. Gilbert, A. M., United States Geological Survey, Washington,

I), c.
;i Georgi B. Grinnell, Ph. D., 318 Broadway, N. V. City
:;.".. William P. E Gurley, Danville, Illinois.

Christopher W. Hall, A. M.. 803 University Ave., Minneapolis, Minn.:

Professor of Geology and Mineralogy in University of Minnesota.
37. James Hall, LL. D., State Hall, Albany, N. V. ; State Geologist and Director

of the State M useum.
- Erabmub Haworth, l'li. D., Oskaloosa, towa; Professor of Natural Sciences

in Penn Col leg
39. Roberi Hay, l!"\ 162, Junction City, Kan
K). Angelo Hbilprin, Academy of Natural Sciences, Philadelphia, I'a. : Professor

of Paleontology in the Academy of Natural Scien<
11. Lewis K. link-. Lincoln, Nebraska; Professor of Geology in the University

of Nebraska.
12 I w Hiloard, Ph. D., LL D., Berkeley, Cal : Professor of Agricult-

ure in l*ni\ ersil \ of < California

LIST OF FELLOWS. 581

43. Robert T. Hill, B. S., Austin, Texas ; Professor of Geology in University of

Texas.

44. Charles H. Hitchcock, Ph. D., Hanover, N. H. ; Professor of Geology in

Dartmouth College.

45. Levi Holbrook, A. M., P. O. Box 536, N. Y. City.

4(3. Joseph A. Holmes, Chapel Hill, North Carolina; Professor of Geology in
University of North Carolina.

47. Jedediah Hotchkiss, 346 E. Beverly St., Staunton, Virginia.

48. Edmund O. Hovey, Ph. D., Waterbury, Conn.

49. Horace C. Hovey, D. D., 14 Park St., Bridgeport, Conn.

50. Edwin E. Howell, A. M., 18 College Ave., Rochester, N. Y.

51. Alpheus Hyatt, B. S., Bost. Soc. of Nat. Hist., Boston, Mass. ; Curator of

Boston Society of Natural History.

52. Joseph F. James, M. S., United States Geological Survey, Washington, D. C.

53. Lawrence C. Johnson, United States Geological Survey, Meridian, Miss.

54. W. D. Johnson, United States Geological Survey, Washington, D. C.

55. James F. Kemp, A. B., E. M., Ithaca, N. Y. ; Assistant Professor of Geology

and Mineralogy in Cornell University.
50. George F. Kuxz, 402 Garden St., Hoboken, N. J.

57. Joseph LeConte, M. D., LL. D., Berkeley, Cal. ; Professor of Geology in the

University of California.

58. J. Peter Lesley, LL. D., 1008 Clinton St., Philadelphia, Pa. ; State Geol-

ogist.

59. W J McGee, United States Geological Survey, Washington, D. C.

60. Frederick J. H. Merrill, Ph. B., Fordham Heights, N. Y. City.

61. Albro D. Morrill, A. M , M. S., Athens, Ohio; Professor of Biology and

Geology in Ohio University.

62. Frank L. Nason, A. B., 5 Union St., New Brunswick, N. J. ; Assistant on

Geological Survey of New Jersey.

63. Henry B. Nason, Ph. D., 31. D., LL. D., Troy, N. Y. ; Professor of Chemistry

and Natural Science in Rensselaer Polytechnic Institute.

64. Peter Neff, A. M., 401 Prospect St., Cleveland, Ohio.

65. John S. Newberry, M. D., LL. D., Columbia College, N. Y. City; Profes-

sor of Geology and Paleontology in Columbia College.

66. Edward Orton, Ph. D., LL. D., Columbus, Ohio; State Geologist and Professor

of Geology in the State University.

67. Amos O. Osborn, Waterville, Oneida Co., N. Y.

68. Richard Owen, LL. D., New Harmony, Ind. (Died March 24, lS'.K).)

69. Horace B. Patton, Ph.D., New Brunswick, N. J.; A.ssistan1 Professor of

Geology and Mineralogy in Rutgers College,

70. William H. Pettee, A. M., Ann Arbor, Mich.; Professor of Mineralogy,

Economical Geology, and Mining Engineering in Michigan University.

71. Franklin Platt, G15 Walnut St., Philadelphia, Pa.

72. Julius Pohlman, M. D., Buffalo Society of Natural Sciences, Buffalo, N\ V.
7".. John W. Powell, Director of U. S. Geological Survey, Washington, D. C.
74. John R. Proctkk. Frankfort, Kentucky ; State Geologist.

7<i. Charles S. Pros>h;k. M. S., 0\ S. National Museum, Washington, D. C.

77. Eugene N. S. Ringuebkrg, M. D., Lockport, N. Y.

78. Israel C. Russell, M. S., United Status Geological Survey, Washington, D. C.

PROCEEDINGS OF NEW YORK MEETING.

79. Jam se M. Safford, M I) . LL. D., Nashville, Tenn. ; State Geologist ; Pro-

n Vanderbilt University.

80. Rollih 1». Salisbury, a. M.. Beloit, Wis< Bin; Professor of.Geologyin

it College.

81. Charles Schaeffbr, M. I'.. 1309 Arch St., Philadelphia, l'a.

82. Nun will S. Shalbb, LL. D., Cambridge, Mass Prof — of Geology in

Harvard University.

Frederick \V. Simonds, Ph. 1).. Austin, Texas; Professor of Geology in Uni-
versity of Texas.
84. Eu< bene A. Smith, Ph.D., University, Tuscaloosa County, Ala.; Profess
of Chemistry and Geology in University of Alabama.

John C. Smock, Pb. D., State Museum, Albany, N. V ; Assistant in Charge
of tlic Stat'- Museum.

Joseph W. Spencer, a. M., Ph. D., Athens, Georgia ; State Geologist.
s7. John .1. Sn \ enson, Ph. I).. University of the City of N". V. ; l'rofessor of
( ,. ology in tin' University of the < !ity of New York.

William I-:. Taylor, Peru, Nemaha <'■>.. Neb.; Teacher of Geology and
Natural History in Nebraska State Normal Sch

89. Asa Scott Tiffany, 901 West Fifth St., Davenport, [owa.

90. James B.Todd, A. M., Tabor, [owa; Professor of Natural Sciences in Tabor

< '"liege.
'.•1. Henry \V. Turner, United States Geological Survey. Valley Springs, Cal.
'.r2. Edward 0. Ulrich, A. M., Newport, Kentucky.

Warren Upham, A. B., 36 Newbury St., Somerville, Ma-.; Assistant on the
I'. S. Geological Survey.
■I Charles R. Vam Hise, M.S.. Madison, Wisconsin; Professor of Mineralogy
and Petrography in Wisconsin University; Geologist, I'. S. Geological
Survey.

95. ANTHONY W. VoGDES, Fori Hamilton. N. Y Harbor; Captain Fifth Artillery.

U. S. Army.

96. Makmimw K. Wadsworth, I'll I).. Houghton, Mich.: State Geologist ; I>i-

tor of Michigan Mining School.
'.17. Charles I). Walcott, U.S. National Museum, Washington, !».<'.; Paleon-
tologist, U. S. Geological Survey.
Israel C. White, Ph.D., Morgantown, W. Va. ; Professor of Geology in

Wesl Virginia University.
I Robbri I'. Whitfield, Ph. D., American Museum of Natural History, 77th

St. ami 8th Av.. \ . Y. City ; Curator of Geology ami Paleontology in

American Museum of Natural History.
mil Edward II Williams, Jr., A. <\. K. M.. 117 Church St.. Bethlehem, Pa.;

Professor of Mining Engineering and Geology in Lehigh University.
101 Georoi II. Williams, Ph. D., Johns Hopkins University, Baltimore, Md. ;

Prof< r of Inorganic Geology in Johns Hopkins University.

102. Henri S. Williams, Ph. !>.. [thaca, N. "i Professor of Geology and Paleon

tology in ( lornell I rniversity.
in.;. .1. Fb I ■' 1 Willi IMS, Ph. D., Salem N. Y.

104 '• W1111 ims, I'll l> . [thaca N. Y. ; P in Cornell University.

105. Alexander Wincuell, LL D., Ann Arbor, Mich. ; Profi Q gyand

Pa • ■ \ in M ichigan tJniversity

LIST OF FELLOWS. 583

106. Horace Vaughn Winchell, 10 Sfate St., Minneapolis, Minn. ; Assistant on

Geological Survey of Minnesota.

107. Newton H. Winchell, A. M.. Minneapolis, Minn.; State Geologist; Pro-

fessor in University of Minnesota.

108. Arthur WlNSLOW, B. S., Jefl'erson City, Missouri; State Geologist.

109. G. Frederick Wright, D. D., Oberlin, Ohio ; Professor in Oberlin Theological

Seminary.

110. Charles A. White, M. D., U. S. National Museum, Washington, D. C. ;

Paleontologist, U. S. Geological Survey.

111. Edwin T. Dumble, Austin, Texas ; State Geologist.

112. Walter A. Brownell, Ph. D., 905 University Avenue, Syracuse, N. Y.

Elected December 27, 1888.

113. James E. Mills, B. S., 2106 Van Ness Avenue, San Francisco, Cal.

114. Henry G. Hanks, 1124 Greenwich St., San Francisco, Cal. ; lately State

Mineralogist.

115. Edward V. d'Invilliers, E. M., 711 Walnut St., Philadelphia, Pa.

116. William M. Fontaine, A. 31., University of Virginia, Va. ; Professor of

Natural History and Geology in University of Virginia.

117. J. C. Fales, Danville, Kentucky ; Professor in Centre College.

118. Adams C. Gill, A. B., Northampton, Mass.

119. Jules Marcou, 42 Garden St., Cambridge, Mass.

120. William S. Bayley, Ph.D., Waterville, Maine; Professor of Geology in

Colby University.

121. A. Wendell Jackson, Ph. B., Berkeley, Cal. ; Professor of Mineralogy, Petrog-

raphy and Economic Geology in University of California.

122. George P. Merrill, M. S., U. S. National Museum, Washington, D. C. ;

Curator of Department of Lithology and Physical Geology.

123. Egbert W. Ells, LL. D.. Geological Survey Office, Ottawa, Canada; Field

Geologist on Geological and Natural History Survey of Canada.

124. Joseph H. Perry, Worcester, Mass. ; Professor of Natural Sciences in the

Worcester High School.

125. P. H. Mell, M. E., Ph. D., Auburn, Ala. : Professor of Geology and Natural

History in the State Polytechnic Institute

126. David Honeyman, D. C. L., Halifax. Nova Scotia: Provincial Geologist.

(Died October 17, 1889.)

Elected May 20, 1889.

127. Uobert Bell, C. E., M. D., LL. D., Ottawa. Canada; Assistant Director of

the Geological and Natural History Survey of Canada.

128. Charles E. Beecher, Ph. I).. Yale University. New Haven, Conn.

129. Richard G. McConnell, A. B., Geological Survey Office, Ottawa, Canada;

Field Geologist on Geological and Natural History Survey of Canada.

130. Joseph B. Tyrrell, A. B., Geological Survey Office, Ottawa. Canada ; Field

Geologist on Geological and Natural History Survey of Canada.

584 PROCEEDINGS OF SEW YORK MEETING.

131. Frank A.. Hill, 208 S. Centre St, Pottsville, Pa. ; Geologisl in Charge of

Anthracite District, 2d Geological Survey of Pennsylvania.

132. Lester F. Ward, A. M., U. 8. Geological Survey, Washington, I). C. ; Pa-

leontologist, U. S. Geologic*! Survey.

133. Frederick P. Dkwkv. Ph. B., Smithsonian Institution, Washington, D. 0. ;

Curator of Department of Metallurgy, U. S. National Museum.
1".}. Charles Whitman Cross, Ph. D., U - G logical Survey, Washington, D. C.
135. Josepb P. Iddings, Ph. B., U. S. Geological Survey, Washington, I>. C.
L36. Arnold II am k. Ph. 15. . U. S. Geological Survey, Washington, I). C.

137. Olives Marcy, LL. D., Evanston, Cook Co., Illinois; Professor of Natural

Eistory in Northwestern University.

138. Sir J. William Dawson, LL. D., McGill College, Montreal, Canada ; Prin-

cipal of McGill University.

139. M.m:v B. Holmes, Ph. I).. 201 S. First St., Rockford, Illinois.

ill). Thomas M. Jackson, C. E., Morgantown, W. Va. ; Professor of Civil and
Mining Knginoerinij in West Virginia University.

141. Robert II. Looghridge, Ph. D., Columbia, Smith Carolina; Professor of

Agricultural Chemistry in University of South Carolina.

142. Frederick II. Newell, I!. S., I". S. Geological Survey, Washington, I). C.

143. Clarence King, 18 Wall St., N. Y. City; lately Director of the U. s.

1 . logical Survey.

111. Robert Simpson Woodward, C E., U. S. Geological Survey, Washington,
D ('.

II".. Moritz Fischer, State Museum, Frankfort, Ky. ; Assistant on State Geolog-
ical Survey and Curator of State Museum.

146. Henry M. Seklt, M. D., Middlebury, Vermont; Professor of Geology in
Middlebury College.

117. Chable8 Wai hsmuth, M. I).. Burlington, Iowa.

148. Franklik R. Carpenter, Ph.D., Rapid City, South Dakota: Professor of

Geology in Dakota School of Mines.

149. Truman II. Axdrich, M. E.,92 Southern Avenue, Cincinnati, Ohio.

150. Orestes II. Si. J ohn, Topeka, Kansas.

151. Richard A. F. Penrose, Jr., Ph.D.. Little Rock, Arkansas; Assistant on

A ■ kansas Geological Survey.

152. .John B Hastings, M. E., Ketchum, Alturas Co., Idaho.

1 .".:;. Robert Ch llmers, Geological Survey oilier. Ottawa, Canada ; Field Geologist
on Geological and Natural History Survey of Canada.

154. Charles W. Hates, Ph. D., U. S. Geological Survey, Washington, D. C.

155. Henri McCalley, A. M , C. £., University, Tuscaloosa County, Ala.; A

mi on Geological Survey of Alabama.

156. Charles W Rolee, M.S., (Jrbana, Champaign Co., Illinois; Professor of

1 . logy in University of I llinois.

157. George M. Dawsom D Sc, A. R S. M., Geological Survey Office, Ottawa,

i i.el.i : Assistant Director of Geological and Natural History Survey of
< lanada.
Stephen Bowerh \ M , San Buena Ventura, California.
159. N. .1. Giroux I I. Geological Survey Office, Ottavt I In Assistant
Field Geologi I Q igical and Natural History Survey of Canada.

LIST OF FELLOWS. 585

160. Clarence L. Herrick, M. S., 14 Mitchell Avenue, Mt. Auburn, Cincinnati,

Ohio; Professor of Geology and Biology in the University of Cincinnati.

161. Samuel B. Howell, M. D.. 1513 Green St., Philadelphia, Pa.; Professor of

Mineralogy and Geology in University of Pennsylvania.

162. William McInnes. A. B., Geological Survey Office, Ottawa, Canada; Assistant

Field Geologist, Geological and Natural History Survey of Canada.
1»;::. Maurice Thompson, Crawfordsville, Indiana ; lately State Geologist.

164. Frank H. Knowlton, M. S., U. S. National Museum, Washington, D. C. ;

Assistant Curator of Botany in U. S. National Museum.

165. Arthur Keith, A. M., U. S. Geological Survey, Washington, D. C.

1GG. Thomas H. McBride, Iowa City, Iowa; Professor of Botany in the State Uni-
versity of Iowa.
1G7. David White, U. S. Geological Survey, Washington, D. C.

168. Frederick D. Chester, M. S., Newark, Delaware: Professor of Geology and

Botany in Delaware College.

169. Alexis A. Julien, Ph. D., Columbia College, N. Y. City; Instructor in

Columbia College.

170. P. J. Farnsworth, M. D., Clinton, Iowa; Professor in the State University

of Iowa.

171. Othniel C. Marsh, Ph. D., LL. D., New Haven, Conn. ; Professor of Paleon-

tology in Yale College.

172. Thomas F. Moses, M. D., Urbana, Ohio ; President, of Urbana University.

173. Henry Donald Campbell, Ph. D., Lexington, Va. ; Professor of Geology and

Biology in Washington and Lee University.

174. Walter H. Weed, M. E., U. S. Geological Survey, Washington, D. C.

175. Andrew C. Lawson, Ph. D., Geological Survey Office, Ottawa, Canada; Field

Geologist on Geological and Natural History Survey of Canada.

176. Amos Bowman, Geological Survey Office, Ottawa, Canada ; Field Geologist on

Geological and Natural History Survey of Canada.

Elected December 26, 1889.

177. George C. Swallow, M. D., LL. D., Helena, Montana; State Geologist;

lately State Geologist of Missouri, and also of Kansas.

178. Albert S. Bickmore, Ph. D., American Museum of Natural History, 77th

St. and 8th Avenue, N. Y. City; Curator of Anthropology in the American
Museum of Natural History.

179. John E. Wolff, Ph. D., Harvard University, Camhridge, Mass.; Instructor

in Petrography, Harvard University.

180. Ezra Brainerd, LL. D., Middlebury, Vermont; President of Middlebury

College.

181. Thomas Sterry Hunt, D. Sc, LL. I)., Park Avenue Hotel, N. Y. City.

182. R. D. Lacoe, Pittston, Pa.

183. Aaron H. Cole, A. M., Hamilton, N. Y. ; Lecturer on Natural History in

Madison University.

184. Frank Dawson Adams. Montreal, Canada; Lecturer on Geology at McGill

College.

586 PROCEEDINGS OF NEW YORK MEETING.

185. Lorenzo (J. Fates, M D., Santa Barbara, California.

186. Henry. M. Ami. A. M., Geological Survey Office, Ottawa, Canada ; Assistant

Paleontologist on Geological and Natural History Survey <>f Canada.

187. Victor C. A.LDER80N, 6721 Honore St., Englew 1. Ills.

188. Alfred K C. Selwyn, CM. G., LL. D., Ottawa, Canada: Director, of Geo-

logical and Natural History Survey of Canada.

189. Bails'] Willis, U.S. Geological Survey, Washington, D. C.

190. Alfred C. Lane, Ph. D., Houghton, Michigan; Assistant on Geological Sur-

vey of M ichigan.

191. Daniel W. Lanodon, Jr., A. B., University Club, Cincinnati, Ohio: Geol-

ogist of Chesapeake and Ohio Railroad C<>.

Summary.

Original Fellows 112

Elected December 27, 1888 ll

Elected May 20, L889 50

Elected December 26, 1880 15

Aggregate 191

Deceased — I

Present membership 187

INDEX TO VOLUME 1,

Page

Acer pleistoeenicum, Founding of species 327

Adams, Frank, (Quotation from, on the Lau-

rentian of Quebec 188

Alaska, Surface geology of 90

Algonkian, Definition of. 238

Am. Ass'n Adv. Sci , Oriuin of. 17

, Relation of G. S. A. to 3

American Geologist, Establishment of 3

Ami, H. M., Fossils collected by 405

Anderson, A. C, Reference to work of, in

Alaska „ 117

Andrews, E., Cited on Pleistocene forest

beds 312

Appomattox formation. Southern extension

of the 546

Archean, Internal relations and taxonomy

of the 175

— , Pre-Paleozoic Surface of the 103

— studies, Results of 357

Arizona, A line of displacement in 49

Asbbubneb, C. A., Obituary notice of 521

— , Cited on rocks of the Hudson valley 346

Association of American Geologists, Origin

of the 17

.Reference to 2

Baer, K. E. von, Reference to, on depth of
frozen soil

Rakrande, Joachim, Reference to work of.....

Barroib, Ch., Quotation from

— , Reference to work of 178, 184, 191,

Bayfield, Admiral, Cited on the "Quebec
group ",

Beaumont, Elie de, Cited on rocks of central
France

Beck, L. C, Cited on the Syracuse serpentine

Becker, G. F., Cited on auriferous slates

Bedding, cleavage, and foliation

Beeches, C. E.. Cited on rocks of the Hudson
valley

Beech ey, Captain, Reference to work of, in
Alaska

Bihbing, Orthography of

Bell, Robert; Glacial Phenomena in Can-
ada

— , On collections of fossil plants by

— , cited on the rocks of Lake Superior

stratigraphy of the Archean

— , Title of paper by

Bickmoke, A. »., Title of paper by

Bigsby, J. J., Cited on the "Quebec group"..

Billin, C. E., On work of, in Pennyslvania...

Billings, E., Cited on Calciferous fossils

fossils of the " Quebec group "

— , On collections of fossil plants by

— , Reference to work of.

Black Hills, Pre-Cambrian rocks of the

Blake, T. A., Reference to work of, in Alaska

Blake, VV. P., Cited on tin ores of the Black
Hills

Bon.vey, T. G., Cited on early Cambrian and
pre-Cambrian formations

the origin of mica slates

Borden, C. H., Cited on the Hudson River
Group ,

Borron, E. B., Cited on relation between in-
lets and dikes

Bowlder belts and bowlder trains

130

40
189

482

454

374
533

279
232

344

127
101

287
315
385
182
523
557
464
521
515
155
315
41
203
138

204

234

223

343

100
27

LXXVIII— Bull. Geol. Soc. Am., Vol. 1, 1889

-r, Page

Bowlder pavements in the region of the

Great Lakes 71

Brainerd, Ezra, and Henry M. Seely; The

Calciferous Formation in the Charnplain

Valley 501

, Title of paper by 519

Branner, J. C. ; Remarks on strength of the

earth's crust 27

Brewer, W. H., Cited on sandstone dikes.... 440
Brogger, W. C, Reference to work of..... 179, 551

Buch, L. von, On work of, in Norway 551

Burbank, L. S., Work of, in Massachusetts... 37

Butte fault, description of 51

By-Laws 574

— , Provisional 8

Calciferous formation (The) in the Cham-
plain valley 501

California, Sandstone dikes in 411

Callaway, O, Quotation from 189

Call, R. E., Work of, in lower Mississippi

valley 470

Calvin, S., Cited on the Hudson River group. 843

Cambrian (Pre-) rocks of the Black Hills 203

Canada, Archean of central 175

— , Glacial phenomena in 287

— (northwt stern), Post- Tertiary deposits of.. 395

— , Pleistocene flora of. 311

— , Pre-Paleozoic surface of the Archean in... 163

Cantwell, J. C, Reference to work of. 127

Cape Fear River region, Tertiary deposits of. 537
Carpenter, F. R., Cited on the geology of the

Black Hills 204, 239

Caswell, J. H., Cited on mineralogy of the

Black Hills 204

CiiAMBERi.iN, T. C: Additional Evidences on

the Interglacial Period 469

— , Bowlder Belts distinguished from Bowl-
der Trains 27

— , Cited on the cause of Pleistocene depres-
sion 5f>7

condition of a melting ice sheet... 190

terminal moraine 3:19

— , Quotation from 84

— , Record of discussion by 536, "II

— , Reference to work of 142

— , Remarks on Alaskan geology 155

Pleistocene phenomena 107

the strength of the earth's crust jr,

— , Title of paper by 623

CiiAMPL.uN valley, The Calciferous forma-
tion in the 501

Chance, H. M., Cited on Pleistocene ter-
races 472

Ciiauvf.net, \V. M., Cited on Lake Superior

geology 391

Clark, W. B.; Tertiary Deposits of the Cape

Fear River Region 637

Claypole, E. W., Cited on the ancient Lake

Brie-Ontario 545

origin of the (J real Lakes 566

Cleavage, bedding, and foliation 232

Cleveland meeting for organization of the

<;. s. a 3

Coal seams, Probablo origin of 127

C ;n, B., Cited on origin of quartz schists.. 218

( Iolorado river, Line of displacement along
the I'l

(587)

588

BULL. GEOL. SOC. AM.

id, T. .V. Cited "ii mingling "f Me

Boic and i •• faunas

i lie Salmon River Bhale ::ii

ind By-Laws t

, l'r..\ isional 7

— , Provisional, Committee on revision of 18

[Rxm u elevation (Higb) preceding the
Pleisl me

— growth, Mode of 18

— progress treas of) in North America 36

— surface. Division of 36

. G. ll., i ibituary notice "f 519

— , Reference t", .>n extrusive origin of

traps Bf,2

work by, in New Jersey 39

E I1.' Ited on the Laramie group 525

— . Ri in arh - on the Laramie '-'roup 55 1

Cornrli University, Meeting in 9

Correlation, Discussion of methods of 481

. E., Reference to map by 168

ii . Report ol "

' "i n i no, Defense of name 183

Cretaceous plants from Martha's Vineyard., 554

— (Tertiary and) deposits ol eastern Mas i

chusetts 443

Crosby, W. O , Cited on the geology "f the

Black Hills 'Jul

Jointed structure I -

oceanic sedimentation j.V.i

the age of the Black Hills crystal-
lines 239

unconformities in the Black Hills... 250

— , Reference i" work of, in Massachusetts... :J>7
Cb — in Mr in.., Significance and illustration

of I i-

Cboto, C. W., Cited on unconformity in the

Elk mountains 261

— . Work of, in the Denver region 284

Cboll, Jambs, Cited on causes <>f changes in

level 309

the length of the post-glacial period, 809

< n\ ptozhom \U • li. Founding •

< lUBOl ' I In' I and il- fauna I- 1

Ctrtia, Relations of, to Spirifera 667

< 'i in isa, Relations of, i" Spirift ra

l>Ah"i\, Pre-Cambrian rocks "f the Black
Hills of 203

lun.T. N , < Ited "ii rocks of the Hudson
valley 344

Dall, W. II, Reference to, on temperatun
of Alaska 153

work Of, in Ala-La 102, 101, 1"-, 126,

127, 137
Dana, J. D.; Areas of Continental Progri

in N"rtii America

— , en.-. I oi cool Inentftl progri

sandstone dike- i 1 1

— significani i fiord* 503

submarine channel ol the Hudson

, Record ol address by

—.Title of paper 18

Dartoh, n. H., Cited on rocks of the Hudson

valley 34 1

Darwin, Chabxes, Quotation from, on Band-
it tone dikes (39

Davidson, Oborob, Cited on submerged val-
leys "i i he P i ■■ ■ t

Davidson, Thomas, Work of, In paleontolog
Inn-, w. M., Cited "ii Beer aft' i Mountain I
— , On Advisory committee on publication

Committee to confer with other socio

tli

— . Record "t discussion by 14, !

, Remarl on andxtone • i 1 1< < - ■- iij

th«- Appomattox formation If

Hudson Klver group

— ; Structure and Origin "t Glacial Band

Plains 105

. I ni. ol | <i ■
Dawson, O. M . .ii ift deposits In iln-
.n..i ihwesl Ti i i Itory

Page
Dawson, G. M , Cited on nggd merates of the

Lake "t the W I- 181

Hriti-li Columbia _'I7, 219

Canadian drift :i'.i7

explorations "i the Yukon

interglacial beds 316

northward iee flow 543

the geology "f the West Coasl 196

Kootanie beds 276

Laramie group •'■'--

— Quotation from 106

— , Reference to work of ... 17

, in Alaska 102, i"i. l«8, 115,

- I 15, 1 10
Dawson, Sir William, and D, P Penhallow;

The Pleisl I lot a of ' ana. la :'.l 1

, Title ol paper by 563

— , cited "ii the Laramie group

Saguenay gorge

— , Remarks on I ' 23

Imi w of rocks 133

I » 1 1 i \ ..f the Yukon 110

Depression during the glacial period, Evi-
dence of 663

Dbbhavbs, G. P., On mingling "I Mexozoic

an.i Cen fau nas

Dbsor, I'... Definition "I Algonquin, by 238

Devbrei \, W. B., Cited "ii gold ores of the

Black Hills

Dbwai que, G . Works of 18*2

Dbwbbs, .). II., Refere t.. work "f. In

Pennsylvania 521

Dewet, Chester, Cited "ii rocks of the Hud-
son valley

osposoiDJB, New species and genera of., 22
Dikes, Sandst -Ill

— (Trap) ii. ar RLennebunkport, Me 'ii

.;, J. 8., ' Sited "ii kimberlite

— : Sandstone hikes ill

— , Title of paper by 557

Disintegration "I rocks

Dispi \. i mi ni in the Grand Ca i, A line of., 19

Dri mmond, a. t.. Cited on the origin "f the

'.real Lake- 660

Duprrnov, P. A , i it.-. I ..ii rocks ol central

I ranee 174

I v, < '. B., Cited mi the Mesozoic of New

Mexico 275

— unconformities in New Mexico 251

the Plateau region

— , Quotation from 50

— , Reference t" work of •'. G2

Dwioht.W. B., Reference t.< finding of los-

sii- by 39

Eau i m. i -. Certain phenomena of I

Earth's crust. Strength of the 23

Baton, \ tos, < Ited on rocks of the Hudson

ley 335

Eldridob, G. If.. ( ited on Dino aurua beds... 267

orographic movements 278

in fortuities in tli" Elk mount-
ains -Id,

— , Work of, in the Denver region

r»N of i el lows 12,

Officers 13,

rtoN and depression, Evidence of.

— i ll iirii .■.nit mental i preceding the P

Elliott, II W., Quotation from, on Alaska...
I .i i -. R, \\ : Stratigraphy "f the "Quebec

Group"

. Title "I paper by

Emerson, 11. K.j Porphyritlc and Gneissoid

'•in. ii. hi Massachusetts

— , R rd >.f dl by

. R i r . ; i ■ i. on Not » ay geolog

Sandstone dlki

i!.' it... I mi mingling of Mi — boIo

an i i ■>■ Ic faunas

the rock* ol the Vilironrlanks 359

Blrdseye formation 509

518

Ill*

II"

IN DEN TO VOL. 1.

589

Page
Emmons, E., Cited on the Calciferous forma-
tion 503

rocks of the Hudson valley 338,341

— , Reference to work of 41

Emmons, S. F., Cited on the geology of the

Black Hills 204

thickness of Cambrian quartzites.. 221

— ; Orographic Movements in the Rocky

Mountains 245

— , Title of paper by 533

— , Use of the term Algonkian by 238

Endlich, F. M.. Cited oo Colorado geology... 249
Erman, Adolph, Reference to, on depth of

frozen soil 130

Eruptive origin of the Syracuse serpentine.. 533

Etheridge, l; , Works of 182

Evidences (Additional) on the interglacial

period 409

Extension (Southern) of the Appomattox
formation 540

Fairi iiii.ii, H. L., On Committee for revis-
ing the Constitution 5, 13

Fault in the Grand Canon 51

Fauna, The Cuboides zone and its is l

Feii.iien. H. W., Quotation from, on Grinnell

Land 314

Fellows, Election of 12,518

— , Original 9

F. G. S. A., Use of, as a title recommended. ..5, 13
Fiords and lake basins of North America... 563

Flora (1'leistocene) of Canada 311

Fok.hste, A. F., Work of, in eastern Massa-
chusetts 417

Foliation, bedding, and cleavage 232

Fort Cassin rocks (The) and their Fauna... .r>l4

Fossils, Cenozoie 317, 539

— , Mesozoic 529, 554

— of the Eureka Devonian 45

Hudson River group 338

— , Paleozoic 343, 347, 348, 355, 362, 486, 490

505, 514,567

— , Pleistocene 317

Frost, Depth of, in Alaska 130

Gardner, J. S., Cited on a fossil arctic flora.. 525

Gas (Natural) Rock pressure of. 87

( Ieikie, A., Cited on the Scottish Highlands.. 235
Geikte, James, Cited on the length of the

post-glacial period 3(10

Gkinitz, H. B., Works of. 482

Geological and petrographical observations

in Norway 551

Geological Society of America, Origin of..... 2

Geologists, Early associations of 2

Geology (Surface) of Alaska 'J!)

Gilbert, G. K., Cited as editor of report on

Black Hills 201,243

■ on lacolites 560

phenomena of the Monongahela 478

— the term Algonkian 238

unconformities in the Plateau re-
gion 248,250

— , Record of discussion by 523,544

— ; The Strength of the Earth's ('rust 23

Glacial epochs, Interval between the 169

— features of the Yukon and Mackenzie

basins 540

— period, Evidance of depression during

the 563

— phenomena in Canada 287

— sand plains, Structure and origin of 195

Glaciation in Alaska 137

Gouch, F. A., Cited on silica of let spring*... 221
'. Ioodfellow, G. E., Cited on effects of the So-

nora earthquake 135

Gossblet, J., Works of -Is.', Is:,, isx

Grand ('anon, A line of displ eemcnl in the.. 49

— region, Stratigraphy of the 60

Granite, Age of Black Hills 212

— , Origin of Black Hills 210

Page

Granite, Porphyritic and gncissoid 559

Granitoid (Oval) areas in t lie lower Lauren-

tian 557

Gravels (High Level) in the region of the

Great Lakes '. 71

Gray, Asa, Cited on the Black Hills 204

Great Lakes, Pleistocene phenomena in the

region of the 71

Gruenewaldt, M. von, Works of 482

Hail, C. W., Work of, in the Black Hills 204

Ball, James, cited on Calciferous fossils 514

Cryptozoon. 504

fossils of the " Quebec group " 455

the Hudson River group 338

— , Farewell address by 570

— , First presidential address by 6, 14

— ; On New Genera and Species of Dictyos-

pongidce 22

— , Presidential address by 15

— , Record of discussion by 549, 550

presidential address by.... 537

— , Reference to work of 40

— , Remarks on the Appomattox formation... 549

Hudson River group 354

Syracuse serpentine 534

— , Response by, to address of welcome 518

— ; Revision of the Genus Orthis 19

— ; The Genus Spirifera and its Relations... 567

Hall, T. M., Works of 482

Hague, Arnold, Cited on quartzites in the

Rocky Mountains 257

thickness of Cambrian quartzites 221

Barker, Alfred, Quotation from L92

Hayden, F. V., Cited on geology of the Black

Hills 203

orographic movements 24'J

the Laramie group 524

Hay, Roiiert, Motion by, on proxy voting 15

— , Remarks on strength of the earth's crust 26
Headden, W. P., Work of, in the Black Hills 204

Heer, Oswald, On a fossil arctic flora 525, 554

Heilprin, Angelo, Remarks on the Laramie

group 527

Herrick, C. L., Reference to work of 44

Hilgard, E. W., Cited on the Orange Sand,

474, 546

lower Mississippi 66

Hilgard, J. E., Cited on submarine channel

of the Hudson 5G4

Hill, R. T., Cited on the Comanche group... 528

marine Cretaceous of Texas 275

unconformities in the Cretaceous 278

— , Reference to work of 41

Hills, R. C, Cited on Eocene in the Rocky

Mountains 286

the Laramie group 281, 524

unconformity below the Jura-Dakota 274

Hindi., (i. .1., Drift deposits on Lake Ontario,

313, 315

Historical sketch of the G. S. A 1

Hitchcock, C. II., cited on absence of Ter-
tiary deposits in New England 566

rocks of Vermont 359

the Calciferous and CoSs group 469

Calciferous formation 603

Montalban 501

— , On Committee for Revision of the Consti-
tution •r>, 13

to draft Provisional Constitution of

G. S. A 4

— ; oval Granitoid Areas in the Lower Lau-

rentian 557

— , Record of discussion by 560,668

— , Remarks on bowlder belts and bowlder

trains 30

the Appomattox formation 548

Calciferous formation 513

— , Secretary of committee to institute a
geologic organization 2

Hitchcock, E., cited on fossil plants from
Martha's Vineyard 555

590

BULL. GEOL. SOC. A.M.

Page
Hitchcock, B.« Cited on geology "f eastern

Massachusetts 1 17

metamorphism of rocks 221

rocks of Vermont

— semi-crystalline .■"hl-i rates

— , influence of, on American Geology 16

— , Reference t" map by av

Mi'iMis, W. H., Cited "it the formations "i

the Gunnison and Grand rivers 274

— , Exploration* by 272

Homogeky, Method of correlation by

Hone yuan, David.* ibituary notice "f 520

11 'kb, ' . I... Reference t", on depth ol fro-
zen soil ISO

work "f. in Alaska 126, u:

Hudson, Definition of. a* imic term.. 353
Hi dsom, Hbnby, Naming of river by

Hi DSON RlVBB group, Value of 1 lie term ....

Ili mis. ,ims, .1. ii., Cited "ii rocks of New

Han 360

Ih si, T. 8., Cited "ii :i mineral species ::7'.i

the Animikie Beries 386

"Quel group" i

BtratiKraphy of the Archean 182

Syracuse serpentine

— , (W. E. Logan and I Reference to founding

"t Huronian l>y 176

Hubbicave fault.... 62

lli \iiv. T. H.. Cited on homotaxy 484, 189

Hydrostatic theory of gas pressure 90

Indiana and Ohio, Pressure of natural gas

in ' 87

Iv.wi., E. !>., Reference i" work of, in t'an-

ad i 1C5

[ntebolacial peri". I, Evidence concerning

the u D

Is i ki -n i origin of the Watcbung traps ..
(aviHo, R. D., Cited on early Cambrian and

pre-Cambrlan formations 234, 238

Lake Uuperioi geology 3f

sandstone veins t:\2

— , Opinions of, on the Huronian 176

1 1 ii a< a Mi el Ing for oi >n of the • ■ .

\ 1,9

Jambs, J. F., Cited on the Hudson River

group 343

term Lauren Man 238

.Ii.sm \, W. P., t;ited "ii the geology of the

Black Hilfs 204

.ii-i p, M. K.. Addn ome by ">is

-, Invitation from

Jomi -, r. R., < Ited "ii di lft-« I in arctic

[ions 316

■Ii do a. Detweilkb, Contract with

K itsi it. E , Works "f

Ki\ir, .1. I-'., Remarks on Byracusi si rpen-

lllie

— ; Trap Dikes near Kennebunkport, Me.... ;;i

Kkwatih, Definition and orthography of :s77

Ki.in in ino, A. von, Works "i i- j

Kino, (im.inm.i Ited on crystalline rocks... .;7i

E ne in the Rocky Mountains 286

orographic movements 246

the Colorado group

thickness of Cambrian qu

, Laramie group named by |

, Ref i work of 16

1 1, I ii . ■ . i i

o yun, Reference i ;. in

Alaska

Kim/in, T i". 1. 1, \\ .»i k ..f, iii ii,e Black

Hills i

I. inn ' dou, G n

Page

I. mi unit, a., Quotation from 167

Lake Agassii 302, 404

— basins, Formation "f 297

"f North America 663

— Bonneville, Certain phenomena "f 24

— Ruperior, Pot-holes north <>f 568

— Yukon, Description of 146

Lappabent, \ i.i.i k i db, Reference to work of. n
Lapwobth, Chablbs, Cited on Paleoaoic grap-

lolites i.v.i, 166

Laramie (The) group 524

Laubbntian, Oval granitoid urea- in the..

— river, Description of I -

Lawson, A. C. ; Internal Relations and Tax-
onomy of the Archean of Central Can-

i 17:.

— , 1 Sited "ii nomenclature 366, -''.77

oval granitoid areas

relations of gneiss and Bchistb.368,376, 383

Norway geology

■ — origin "f pseudo-conglomerates 2 16

— , Record "i discussion by 687

mark- "ii gas pressure 06

strength "f the earth's crust 27

— ; The Pro-Paleozoic Surface of the Ar-
chean in Canada

— , Tide of paper by Mil, 562

Lawson, Gxo., Obituary notice by 520

1 1 , .1 , Geologic explorations of 246

— , mi Advisory Committee on Publication ...6, 14

l.i mm \ s s, J., Reference to work "f 17s, pij

Lesley, J. P., Cited on natural gas pressun

— , < Ibituary notice by 521

1 1 in 1 \, I.1.1, Cited on the Laramie

group 525

Lewis, H. C., Cited on deposits of the I 'ela-

ware 17:

kiraberlite 533

Lindenkohl, a , Cited on submerged valleys

"f the Atlantic coast 67, 5t 1

l.i M". in a, Waldemab, Reference i" work "f.. 46

-., sin William, Classification of 608

— , Cited "ii Calciferous fossils .r>i5

effect of heterogeneity on dislnte-

g ration

rocks of Canada 860

Lake Superior

tile Hudson valley 339

the "Quel group" 164,468, 162

— an.l T. B. Hunt, Reference t" founding "i

Huronian by 176

Low, A. P., Refers ■ to, on hummocky Ar-
chean surfaces ll B

Lyxll, Bib Chablbs, Cited on effects oi New

Madrid earthquake 136

geology "f the southern Atlantic

— Reference t", on depth "i 1 n s..ii 130

MacFarlane, Thomas, Cited on rocks north

of Lake Superior 188

Mackeheij and Yukon basins. Glacial P

till 1- "f .rilO

Maooun, J., Cited on distribution of Canadian

plants

Maoasini (geological), Proposal !•» estab-
lish a J

M initoba, Post- I'ertiary depo-its • •! 396

Mabcod, Jules, Cited on the Mesosoii ■ •! New

Mexico

" Quebec group " 1

ploral i"n- of 246

O. ( . ' Ited on the Dinotaurut beds... 267

Laramie l: 1. -u |>

Martha's Vimi mii us plants from. 564

Mabvihe, a. i: , 1 ne, 1 on the Lai amis ....

, Explorations by 272

Massachusetts, Deposits of eastern 143

, I '"i phvi in- an. I gneissold granites In

Matheb, W. W., Cited on 1 on •"!

1 the Hudson valley

, Reference t" work of 11

INDEX TO VOL, I.

59]

Page
McConnbll, R. G.; Glacial Features of the

Yukon and Mackenzie Basins 540

— , Cited on Alaskan geology 408

Tertiary conglomerates 33fi

the terminal moraine 399

— , Reference to work of, in the Rocky

Mountains 47

, Alaska 1(12, 138

McGee, W J, Cited on condition of a melting

ice sheet 100

early Pleistocene deposits 473

sandstone dikes of Mississippi 44*1

— , On Advisory committee on publication.. .r, 14

— , Record of Discussion by 523, 537, 544

— , Remarks on gas pressure 96

Pleistocene deposits 474, 481)

submergence 409

— , Report on publication presented by 15

— ; The Southern Extension of the Appo-
mattox Formation 54C

McGeath, J. E., Work of, in Alaska 101

McKellae, Donald, Discovery of pot-holes

by 508

McKellae, Peter, Cited on ancient pot-holes 208

— ; Pot-Holes North of Lake .Superior 508

McKellae, William, Cited on the stratig-
raphy of the Arcliean 182

McMahon, C. A., Cited on the gneiss of the

Himalaya mountains 190

Meek, P. B., Cited on the Hudson River

group 343

Laramie group 520

unconformities in the Cretaceous.... 278

Meeeiam, W. N., Cited on Lake Superior ge-
ology 301

Merrill, F. J. H., Record of discussion by... 523
— , Remarks on Cretaceous plants from Mar-
tha's Vineyard 550

the deposits of the Delaware 477

— , Title of paper by 568

Metamorphism, Studies of. 219

Michel-Levy, A., Cited on crystalline rocks.. 374
Miller, J G., Collections of fossil plants by.. 315

Mills, J. E., Record of discussion by 544

— , Remarks on Pleistocene Phenomena 407

Moraine (A) of retrocession in Ontario 544

Mourlon, Michel, Works of 482

Muir, John, Quotation from, on Alaska 141

— , Reference to work of, in Alaska 125, 137

Muechison, R. I., Reference to work of. 40, 482

Nason, Frank L. ; Intrusive Origin of the

Watch ung Traps 562

Naumann, C. P., Cited on Norway geology.... 55L
Neff, Peter; The Sylvania Sand in Cuya-
hoga County, < thio 32

Nelson, E. W., Reference to work of, in

Alaska 120

Neum ayr, Melchiob, Cited on Jurassic move-
ments 279

Newberry, J. S., Cited on Mesozoic of New

Mexico 274, 277

origin of the Great Lakes 500

Pleistocene forest beds 312

— , Geologic explorations of 245

— , Record of discussion by 533

— , Reference to work of 42

— , Remarks on Cretaceous plants from Mar-
tha's Vineyard 555

Norway geology 552

— ; The Laramie Group 524

New Jersey, Intrusive origin of traps of 502

Newton, Heney, Cited on appearance of tour-
maline in granite 227

geology of the Black Hills 190,204,

205, 243

unconformities in the Black Hills... 250

Nomenclature, Geologic 335

Normal School, Toronto, Meeting in 15

North America, Areas of continental prog-
ress in 36

Page
Norway, Geological and pelrographical ob-
servations in i II

N"\ \ Scotia, Glaciation in 293

Obituary notices [g

Oekleet, Daniel, Works of 482

Officers, Election of 619

— for 1889 5, 13, :,to

Ohio and Indiana, Pressure of natural gas in. 87

Ontakian system, Definiti f 1 77

Ontario, a moraine of retrocession in 544

Orographic movements in the Rocky .Mount-
ains 245

Grand Canon region ;,|

I IRTHIS, Revision of the melius pi

Orton, Edward, Cited on Pleistocene forest

l ".is 312

the Hudson River group 350

— , On Committee to draft provisional Con-

stituti f i'. s^. A 4

— ; Origin of the Rock Pressure of Natural

Gas 87

— , Quotation from 32

— , Title of paper by 537

Paleozoic (Pre-) surface of the Archean 163

Palincenktic drainage, Definition of 549

Passes, Alaskan in;;

Peale, A. C, Cited on contact of Carbonifer-
ous with Archean 266

orographic movements 249

silica of hot springs -jiii

Penhallow (D. I'.), Sir William Dawson and;

The Pleistocene Flora of Canada 311

— , Title of paper by 55:5

Peecival, J. G., cited on Connecticut geol-
ogy 557

Petrogeaphical observations in Norway 551

Phillips, John, Works of 482

Plains, Glacial sand 105

Pleistocene flora of Canada 31 1

— , High continental elevation preceding

the 05

Pobodite, Definition of :;si

Porphyuellite, Definition of 379,381

Pot-Holes north of Lake Superior 508

Powell, J. W., Cited on the Colorado river... 248

thickness of Camhrian quartzites 221

unconformities in the Plateau re-
gion 250, 258

— , Reference to work of .' 17, 50

Preglaciaj continental elevation, Evidence

of 5i;:;

Pressure ( Rock) of natural gas 87

Procter, .1. I!., < >n 1 lommittee to draft provis-
ional constitution of G. S. A I

— , Record of discussion by 523

— , Remarks on the 1 (range Sand I7l

Protaxis, Definition of 30

I'iioxy voting, Proposal U) provide for 13, 15

Publh viion. Advisory committee on 11

"Quebec group," Stratigraphy of the 163

Reusch, H. II., cited on semi-crystalline con-
glomerates -'37

Norway geology 651

— , Reference to work of 17s

Richardson, James, Cited on the "Quebec

group" 151

Ru 11 irdson, John, Reference to, on depth of

frozen soil 130

RlCHTHOFEN, I''. \ on. Works Of I - '

Rock, Decay of 1*1

pressure of natural '_ra< 87

Rork\ Mountains, Orographic move nts

in the 215

Roemer, C. !•'., Work of 482, 186

Roemer, F. A., Work of 482, 485

592

BULL. GEOL. SOC. AM.

1 ;•■'.> as, II. I >., Connection of, with th< \ -

"iaiiim "f American Geologists 17

Rogriu (Tiii Brothers), Cited "ii rocks "i

Pennsylvania and Virginia

Hon <• u .Courtesy of IS

Roth, Justus, Cited on the silica of t j « » t

inir- _'J 1

Hi .»-M i , I. C; Notes on the Surface Geoli

Alaska

—, Cited on Alaskan geology 408

- , R I of discussion by n

. Reference to, on rock decay 134

— , Title <>f paper by o3-l

Safford, J. M., Cited on the Nashville group.. 342

— , Reference t" work "f 17

swn plains. Glacial 195

Sandbtoni dikes Ill

Sa lisbu by, R. D., Cited on early Pleistocene

deposits 17'J

— . Work <>r, in lower Mississippi region 463

Bauer, A., »it<-'l on Bemi-crystalline con-
glomerates 237

Sayles, Iba, Collections by \*i

8< ii m b, J., Works "f 482

s. iiwatka, Fbi dbbii k, Reference t<> work "f,

in Alaska 145, 140

Sedgwick, Adam, Reference to work of 10

.-Mil (Henri M , Ezra Hrainerd and; The
iferous Formation "f the Champlain

Valley 501

, Title of paper by 543

Si i»i\, A. R. C, < ited on the " Quebec

group" 157

stratigraphy "i the Archeau ixj

. i — lis collected by MM

mim, Eruptive origin <>f 533

Shai.es, N. 8., Cited on Martha's Vineyard.., .'<". 1

. I rd of discussion by

— , Remarks on Alaskan geology 155

Pleistocene climate 103

— ; Tertiary and Cretaceous Deposits <>f

. tern Massachusetts 1 1 :

— , Title of paper by 623

Shores (Ancient) in the region "f the Greal

Lakes

S-Foi d (The), A prevailing structural type...
Silurian, Argument for retention of old defi-
nition <>l

Sihmott, C. P., Work of, iii eastern Massa-
chusetts

s,,i ii ii, Geological, organised about 1824 ....
Bobby, II. <'., ' it'll on origin of cleavag

Sowebhy, G. I; , Works of

Species (New), Founding "f 327,

mi m i k, J. W.; Ai >w Ider

Pavements and High Level Gravels

— ; High Continental Elevation prei

— , < ited on drift ol Lake Ontario

origin "f the Great Lakes

ii,. • L'erm Algonklan

, Recoi 'I "I 'h icussloii by i 1 1, G 10,

— , Remarks on ;i moraine "i retrocession in

' intai i"

pi, Istocene submerge! 109

the pre-Pali urfa i the Ai-
nu 17-t

■ , Titles of papers

Spibiprka i i'he Genus) and it- relations...
si inn i bin *. Relation - "f, t"

in Brow s, .1 . mi-

by i i

— , \\ ork of, on 1 1 i

SI I I I . .1. II , ' ■ i

-. .i .1 , < Sited "ii orographic mi
menl

phenol lie Monongahela I7U

the Ii iramle m oup

Wet Moil

— , On Committee for thu revision ol i

luti'.n 5, i •

71
271

117
16

182

M ' I

71
310

..II

Page

enron, J. .)., <in Committee t ifer

with other societies ... . 650

-draft provisional < stilution "f

G - \ 1

: Proceedings of Hip New York Meeting... "'17
— : Proceedings of the Toronto Meeting, etc I
— , Remarks on strength of the earth's crust 20

the Laramie group 632

Stewart, John, Collections "f. 32C

si . John, O. II . Reference t" work >•( 17

Stratigraphy "f the Grand Canon region. .. 50

" < i '•■ i ■■■!• group"

. I'...' ii.- I on batholiles 500

Jurassic movements 279

Surface geology of Alaska 99

— i Pre-Pali i hean 16 I

Sylvania sand (The) in Cuyahoga County,

Ohio :!i

Syracusi serpentine, Eruptive origin of 533

Syringothyuis (Relations of) to Spir if era....

Taxonomi of the \rchean 176

I i ill, J. J. H., Cited on metamorphism 220

— , Reference ti> work of l t*»

Terraces "ii the \' i * 1; ■ j i » river ill

Tertiary and Cretaceous deposits "f eastern

Massachusetts 1 1 ;

— deposits of the Cape Fear river region r«:i7

lri; riABY (Posi deposit - of Manitoba .. ..
Thomson, Sib William, Reference t -fli-
nt by 131

Toronto, Semi annual meeting nt 15

Townshbnd, J., Collection of fossil plants by. 316

Ti:w dikes near Kennebunkport, Me :tl

— , Intrusive origin of

I'renton limestone, Rock pressure "I natu-
ral gas in tin*

Tschernei hew, I'm , Works of 182

'Fully limest , Correlation ofthe It

'1'umdra, Definition of 125

Tuom by, M., Cited on mingling of Me*ozoic

and Cenozoic faunas

Tt km i;, .1. II., Work of, iii Alaska KM

Turner, L. M., Reference i" work of, in

Alaska l-''.

Tt iiii.ll !• , Cited "ii the Black Hills 204

Ti icui.i.i., J. B., Cited "ii the Laramie group

:i Pleistocene fauna

lections by \ii\

— : Post Tertiary Deposits of Manitoba....

-, Reference to work of 17

— , Remarks mi the Laramie group

— , Title of paper by ■! i

Tyndall, J., Cited on the plasticity of quartz. 222

Uph am, Warren, < ited on the condition of a

melting ice sheet i 96

Lake Agaisiz i"i

terraces ol the Merrimac J" I

— ; The Fiords and Lake Basins "I North

America

[' . s Coabi and Geoi Burvky, Acknowl-

. dgments t" l"l

i , S. Gi I'M Survey, Acknowledgments

to I"l

Ussiii R, W. A. K.. Works ol 182

\ is lli-i, i'. R., Cited "ii Lake Superior ge

igy

quartzites in the Rocky Mountains

tli gin "i in tea- schists

I "t 'h-' ussion by

\ i ohean -i udies

— ; The Prot'ambrlan Rocks of the Black
Hilis

— -, Til r by

IFF, A L., Wo f

Vani mm. Lardner, ' ited on rocks "f the

Mohnwl • ■ .

in: ine

Ion of, n nil the Ass'u Am. Gaol... 17

tNDEX TO Vol.. I.

593

r«Ko

Yi, iivki-ii, E. DK, Works of 482

Vlkuazam, Giovanni, Discovety of Hudson

river by 335

Volcanic dusl in terraces 145

Watchung traps, Intrusive origin of the 562

Wadbworth, M. E., Opinion of, on Archean

literature 358

Walcott, 0. D.; A Line of Displacement in

the Grand Canon 49

— , Cited on the Cbuar ami Grand Uaiinn se-
ries .51

Eureka Devonian 45

sandstone dikes -1 in

western Algonkian deposits 258

— , Finding of Cambrian fossils by 39, 559

— , Lowest Cambrian fauna of 460

— , Record of discussion by 551)

— , Remarks on the Appomattox formation... 549

■ Calcife ions formation 512

Cuboides zone and its fauna -KM)

— , Title of paper by,' 31, 54!)

— , Use of term Algonkian by 238

— ; Value of the Term '"'Hudson River

Group" in Geologic Nomenclature 335

— , Work of, on Quebec rocks 466

Ward.L. P., Cited on the Laramie group .283,525
— , Remarks on Cretaceous plants from Mar-
tha's Vineyard 555

the Laramie, group ft-.'!!

— , Work of, on Martha's Vineyard 554

Warren, G. K., Cited on the Mississippi

Cafion OG

Westing ise.Geo., Jr.,( Opinions of, concern-
ing gas pressure 95

Weston, J. C., Collections of 32fi

Weston, T. C, Fossils collected by 464

Whidboi rne, G. F., Works of 482

Whiteaves, J. F., Cited on a Pleistocene

fauna 317

White, C. A., Cited on auriferous slates 279

contact of Cretaceous and Carbon-
iferous 267

fresh-water .Jurassic fossils 252

Mesozoic shore lines.. 276, 2H0

orographic movements 246

the Comanche group 528

Hudson River group 343

Laramie group 281, 283, 530

White, David; Cretaceous Plants from Mar-
tha's Vineyard 554

White, I. <'., Cited on natural gas pressure... s:i
— , i In Advisory committee on publication.. 5, 14

— , Record of discussion by 523, 537

— , Remarks on deposits of the Mononga-

liela 477, 479

gas pressure 95

Whitfield, J. E., Cited on the silica of hot

springs 221

Whitfield, R. P., Cited on the rocks of the

Hudson valley 344

paleontology of the Black Hills... 204

— ; The Fort Cassin [locks and their Fauna. 514

— , Title of paper by 54!)

Whitney, J. D., Cited on sandstone dikes I In

— .Opinion of, on Archean literature 358

Page
Whittlesey, C, filed on Pleistocene forest

beds 312

Williams, G. II. : Geological and I'elrograph-

ical Observations in Norway 551

— , ('itcd on green-stone schists 230

— ; (in the Eruptive Origin of the Syracuse

Serpentine 533

— , Remarks on oval granitoid areas 558

Williams, U.S., ('ilea on the terms Devon-
ian and Devon

— , on Committee for revision of the Consti-
tution 5, 13

— , Reference to work of 42, 1 1

— ; The Cuboides 7. 'lie and its Fauna -I s l

— , Title of paper by 550

Williams, 8. G , • 'bed on the Tully fauna .... 4!)6

WlNCHELL, A., cited on clastic granites 235

oval granitoid areas 558

the stratigraphy of the Archean... 182, 191

— , Historical sketch of the G.8. A l

— , on Committee for revision of the Consti-
tution 5, 13

to confer with other societies 6:0

draft provisional Constitution 4

— , Opinions of, on the Huronian 176

— , Record of discus-ion by "i| |

— , Remarks on bowlder belt- and bowlder

trains 29

strength of the earth's crust 25

— ; Results of Archean Studies 357

— , Titie of paper hy 5.",7

— , Vice-presidential address by It

WlNCHELL, II. V., Cited on Minnesota ge-
ology 366, 372, 375

Winchell, N. H., Chairman of Committee to

institute a geologic organization 2

— , Cited on geology of the Black Hills 203

Minnesota geology 3i;8, 388

Pleistocene forest beds 312

the Animikie formation 37!)

— , On Advisory committee on publication... 5, 14

— , Opinions of, on the Huronian nc

Wing, A., Cited on Vermont geology 506

— , Reference to finding of fossils hy 39

Woodward, It. 9., Discussion of depth of

frost in the arctic |:;o

— , Ratio of interstices to grains in qtiartzite 220
Woodworth, .1. I'.., Work of, in eastern Mas-
sachusetts 449,452

Wolff, .1. E., Cited on Cambrian and pre-

Cambrian rocks 559

— , Record of discussion by 568

Worthen, A. H., Cited on Pleistocene lorest

beds 312

the Hudson River gn.up 343

Wright, G. I'".: A Moraine of Retrocession

in Ontario 544

— , cited on a rock shell' on the Ohio I7:i

— , Reference to work of, in Alaska 162

— , Remarks on bowlder belts and bowlder

trains 2!l

Vikiin and Mackenzie basin-. Olaeial fea-
tures of the 5lo

Yukon (bake), description of Hi;

Yukon river, Nomenclature of 104

, Work on the Ml

CONSTITUTION

OF THE

GEOLOGICAL SOCIETY OF AMERICA.

CONSTITUTION

OF THE

Geological Society of America,

PREAMBLE.

The Fellows of The Geological Society of America, organ-
ized under the provisions of the Constitution approved at Cleve-
land, Ohio, August 15, 1888, and adopted at Ithaca, New York,
December 27, 1888, hereby ordain the following revised Consti-
tution :

ARTICLE I.

NAME.

This Society shall be known as The Geological Societv
of America.

ARTICLE II.

OBJECT.

The object of this Society shall be the promotion of the
Science of Geology in North America.

ARTICLE III.

MEMBERSHIP.

The Society shall be composed of Fellows, Correspondents
and Patrons.

1. Fellows shall be persons who are engaged in geological
work or in teaching geology and resident in North America.

Fellows admitted without election under the Provisional
rsTiTUTiON shall be designated as Original Fellows on
all lists or catalogues of the Society.

J. Correspondents shall be persons distinguished for their
attainments in Geological Science and not resident in North
America.

3. Patrons shall be persons who have bestowed important
favors upon the Society.

4. Fellows alone shall be entitled to vote or hold office in
the Society.

ARTICLE IV.

OFFICERS.

1. The Officers of the Society shall consist of a President,
First and Second Vice-Presidents, a Secretary, a Treasurer, and
six Councilors.

These officers shall constitute an Executive Committee, which
shall be called the Council.

•■>.. The President shall discharge the usual duties of a presid-
ing officer at all meetings of the Society, and of the Council. He
shall take cognizance of the acts of the Society and of its
officers, and cause the provisions of the Constitution and By-
Laws to be faithfully carried into effect.

3. The First Vice-President shall assume the duties of Presi-
dent in case of the absence or disability of the latter. The
Second Vice-President shall assume the duties of President in
case of the absence or disability of both the President and First
Vice-President.

1. The Secretary shall keep the records of the proceedings
of the Society, and a complete list of the Fellows, with the dates
of their ele< tion and disconnection with the society. He shall
also be the Secretary of the Council.

The Secretary, shall co-operate with the President in atten-
tion to the ordinary affairs of the Society. He shall attend to the
preparation printing and mailing of circulars blanks and notifi-
cations of elections and meetings. He shall superintend other
printing ordered by the Society, or by the President, and shall
have charge of its distribution under the direction of the
Council.

The Secretary, unless other provision be made, shall also act
as Editor of the publications of the Society, and as Librarian
and Custodian of the property.

5 The Treasurer shall have the custody of all funds of the
Society. He shall keep account of receipts and disbursements
in detail, and this shall be audited as hereinafter provided.

6. The Society may elect an Editor, to supervise all matters
connected with the publication of the transactions of the Society
under the direction of the Council, and to perform the duties of
Librarian until such time as, in the opinion of the Council, the
Society should make that an independent office.

7. The Council is clothed with executive authority, and with
the legislative powers of the Society in the intervals between its
meetings ; but no extraordinary act of the Council shall remain
in force beyond the next following stated meeting, without rati-
fication by the Society. The Council shall have control of the
publications of the Society, under provisions of the By-Laws,
and of resolutions from time to time adopted. They shall re-
ceive nominations for Fellows, and on approval by them, shall
submit such nominations to the Society for action. They shall
have power to fill vacancies ad interim, in any of the offices of
the Society.

8. Terms of Office. The President and Vice-Presidents
shall be elected annually, and shall not be eligible to re-election
more than once until after an interval of three years after retir-
ing from office.

The Secretary and Editor shall be eligible to re-election
without limitation.

The term of office of the Councilors shall be three years;
and these officers shall be so grouped that two shall be elected,
and two retire each year. Councilors retired shall not be re-
eligible till after the expiration of a year.

ARTICLE V.

VOTING AND ELECTIONS.

1. All elections shall be by ballot. To elect a Fellow, Cor-
respondent or Patron, or impose any special tax, shall require
the assent of nine tenths of all Fellows voting.

2. Voting by letter may be allowed.

3. Election of Felloius. Nominations for fellowship may
be made by two Fellows according to a form to be provided by
the Council. One of these Fellows must be personally ac-
quainted with the nominee and his qualifications tor member-
ship. The Council will submit the nominations received by
them, if approved, to a vote of the Society in the manner provi-
ded in the By-Laws. The result may be announced at any
stated meeting ; after which notices shall be sent out to Fellows
elect.

4. Election of Officers. Nominations for office shall be made
by the Council. The nominations shall be submitted to a vote
of the Society in the same manner as nominations for fellowship.
The results shall be announced at the Annual Meeting ; and the
officers thus elected shall enter upon duty at the adjournment of
the meeting.

ARTICLE VI.

MEETINGS.

1. The Society shall hold at least two stated meetings a
year — a Summer Meeting at the same locality, and during the
same week as the annual meeting of the American Association
for the Advancement of Science — and a Winter Meeting. The
date and place of the Winter Meeting shall be fixed by the
Council, and announced by circular each year within a month
after the adjournment of the Summer Meeting. The programme
of each Meeting shall be determined by the Council, and an-
nounced beforehand, in its general features. rl he details of the
daily sessions shall also be arranged by the Council.

2. The Winter Meeting shall be regarded as the Annual
Meeting. At this, elections of Officers shall be declared, and
the officers elect shall enter upon duty at the adjournment of
the Meeting.

3. Special Meetings may be called b\ the Council ; and must
be called upon the written request of twenty bellows.

1 Stated Meetings of the Council shall be held coincidently
with the Stated Meetings of the Society. Special meetings may

be called by the President at such times as he may deem
necessary.

5. Quorum. At meetings of the Society a majority of those
registered in attendance shall constitute a quorum. Five shall
constitute a quorum of the Council.

ARTICLE VII.

PUBLICATION.

The serial publications of the Society shall be under the
immediate control of the Council.

ARTICLE VIII.

AMENDMENTS.

1. This Constitution may be amended at any annual meeting
by a three-fourths vote of all the Fellows, provided that the
proposed amendment shall have been submitted in print to all
Fellows at least three months previous to the meeting.

2. By-laws may be made or amended by a majority vote of
the Fellows present and voting at any annual meeting provided
that printed notice of the proposed amendment or by-law shall
have been given to all Fellows at least three months before the
meeting.

BY-LAWS.

CHAPTER I.

OF MEMBERSHIP.

1. No person shall be accepted as a Fellow unless he pay his
initiation fee, and the dues for the year, within three months after
notification of his election. The initiation fee shall be ten (K1)
dollars and the annual dues ten (10) dollars, the latter payable
on or before the annual meeting in advance ; but a single
prepayment of one hundred (100) dollars shall be accepted as
commutation for life.

2. The sums paid in commutation of dues shall be invested,
and the interest used for ordinary purposes of the Society
during the payer's life, but after his death the sum shall be
covered into the Publication Fund.

3. An arrearage in payment of annual dues shall deprive a
Fellow of the privilege of taking part in the management of the
Society, and of receiving the publications of the Society. An
arrearage continuing over two (2) years shall be construed as
notification of withdrawal.

•i. Any person eligible under Article III. of the Constitution
may be elected Patron upon the payment of one thousand
(1,000) dollars to the Publication Fund of the Society.

CHAPTER II.

OF OFFICIALS.

I. The President shall countersign, if he approves, all duly
authorized accounts, and orders drawn on the Treasurer for
the disbursement of money.

'.'. The Secretary, until otherwise ordered by the Society,
shall perform the duties of Editor, Librarian and Custodian of
the property of the Society.

3. The Society may elect an Assistant Secretary.

4. The Treasurer shall give bonds, with two good sureties
approved by the Council, in the sum of five thousand dollars,
for the faithful and honest performance of his duties, and the
safe-keeping of the funds of the Society. He may deposit the
funds in hank at his discretion, but shall not invest them with-
out authority of the Council. His accounts shall be balanced
as on the thirtieth day of November of each year.

5. In the selection of Councilors the various sections of
North America shall be represented as far as practicable.

6. The minutes of the proceedings of the Council shall be
subject to call by the Society.

CHAPTER 111.

OF ELECTION OF MEMBERS.

1. Nominations for fellowship may be proposed at any time
on blanks to be supplied by the Secretary.

2. The form for the nomination of Fellows shall be as
follows :

In accordance with his desire, we respectfully nominate for Fellow
of the Geological Society of America :

(Full name)

(Address)

(Occupation)

(Branch of Geology now engaged in, work already done, and
publications made)

(Degrees, if any)

(Signed by at least two Fellows)

The form when filled is to be transmitted to the Secretary.

3. The Secretary will bring all nominations before the
Council, at either the Winter or Summer Meeting of the Society,
and the Council will signify its approval or disapproval of each.

4. At least a month before one of the stated meetings of the
Society, the Secretary will mail a printed list of all approved
nominees to each Fellow, accompanied by such information as
may be necessary for intelligent voting. But an informal list of
the candidates shall be sent to each Fellow at least two weeks
prior to distribution of the ballots.

5. The Fellows receiving the list will signify their approval
or disapproval of each nominee, and return the lists to the
Secretary.

6. At the next stated meeting of the Council the Secretary
will present the lists, and the Council will canvass the returns.

7. The Council, by unanimous vote of the members in
attendance, may still exercise the power of rejection of any
nominee whom new information shows to be unsuitable for
fellowship.

8. At the next stated meeting of the Society, the Council
shall declare the results.

9. Correspondents and Patrons shall be nominated by the
Council, and shall be elected in the same manner as Fellows.

CHAPTER IV.

OF ELECTION OF OFFICERS.

1. The Council shall designate three candidates for each

office.

2. The form for the nomination and election of officers,
unless otherwise provided by the Council, shall be as follows :

The Council nominates for Officers of the Geological Society of
America, for the ensuing year, the following persons :

(The voter will indicate his preference out of each of the sets of
names below by erasing the two other names in each set, or will substitute
the name of his choice.

fl.

For President,

For First Vice-President,

For Second Vice-President,-, 2.

I::

For Secretary,

is.

For Treasurer,

For Councilor,

Fot Councilor.

3.
fl.

::.
'1.

[8.

The Secretary will mail a copy of this ballot to each Fellow,
who after making up the list will return it to the Secretary.

3. At the winter meeting of the Council, the Secretary will
bring the returns of ballots before the Council for canvass, and
during the winter meeting of the Society, the Council shall
declare the results.

4. In case a majority of all the ballots shall not have
been cast for any candidate for any office, the Society shall
by ballot at such winter meeting, proceed to make an election
for such office from the two candidates having the highest
number of votes.

CHAPTER V.

OF FINANCIAL METHODS.

1. No pecuniary obligation shall be contracted without
express sanction of the Society or the Council. But it is to be
understood that all ordinary, incidental and running expenses
have the permanent sanction of the Society, without special
action.

2. The creditor of the Society must present to the Treasurer
a fully itemized bill, certified by the official ordering it, and
approved by the President. The Treasurer shall then pay the
amount out of any funds not otherwise appropriated, and the
receipted bill shall be held as his voucher.

3. At each annual meeting, the President shall call upon the
Society to choose two Fellows, not members of the Council, to
whom shall be referred the books of the Treasurer, duly posted
and balanced to the close of November thirtieth, as specified in
the By-Laws, Chapter II., Clause 4. The Auditors shall examine
the accounts and vouchers of the Treasurer, and any member or
members of the Council may be present during the examination.
The report of the Auditors shall be rendered to the Society
before the adjournment of the meeting, and the Society shall
take appropriate action.

CHAPTER VI.

OF PUBLICATIONS.

1. The publications are in charge of the Council and under
its control.

2. One copy of each publication shall be sent to each Fel-
low, Correspondent, and Patron, and each author shall receive
(30) thirty copies of his memoir.

CHAPTER VII.

OF THE PUBLICATION FUND.

1. The Publication Fund shall consist of moneys paid by
the general public for publications of the Society, of donations
made in aid of publication, and of the sums paid in commutation
of dues, according to the By-Laws, Chap. I., Clause 2.

2. Donors to this fund, not Fellows of the Society, in the
sum of two hundred dollars, shall be entitled without charge, to
the publications subsequently appearing.

CHAPTER VIII.

OF ORDER OF BUSINESS.

1. The Order of Business at Annual Meetings shall be as
follows :

(1) Call to order by the Presiding Officer.

(2) Introductory ceremonies.

(3) Statements by the President.

(4) Report of the Council.

(5) Report of the Treasurer, and appointment of the

Auditing Committee.

(?) Declaration of the results of the ballot for new Fel-
lows.

(8) Announcement of the hour and place for the Address,

of the last ex- President.

(9) Necrological notices.

(10) Miscellaneous announcements.

(11) Business motions and resolutions and disposal there-

of.

(12) Reports of committees, and disposal thereof.

(13) Miscellaneous motions and resolutions.
(1-t) Presentation of memoir

2. At an adjourned session, the order shall be resumed at the
place reached on the previous adjournment, but new announce-
ments, motions and resolutions, will be in order before the
resumption of the business pending at the adjournment of the
last preceding session.

3. At the Summer Meeting, the items of business under
numbers (4), (5), (6), (8), (9), shall be omitted.

4. At any Special Meeting, the Order of Business shall be
(1), (2), (3), (7), (10), followed by the special business for which
the meeting was called.

THE GEOLOGICAL SOCIETY OF AMERICA

RULES RELATING TO PUBLICATION

ADOPTED BY THE COUNCIL
AntiL 21, 1891

ROCHESTER

Pi BUSHED KV 1 ill; Sucn.i J

July, 1891

THE GEOLOGICAL SOCIETY OF AMERICA.

RULES RELATING TO PUBLICATION.

General Rules.

Section 1. The duties of the Editor are, to receive material offered
for publication; to examine the same and submit it to the Publication
Committee, with estimates as to cost of publishing; to publish all
material accepted for that purpose by the Council or Publication Com-
mittee; to revise proofs in connection with authors; to prepare lists of
contents and general indices; to audit bills for printing and illustrating:
and to perform all other duties connected with publication which are not
assigned to other officers.

Section 2. The Council shall annually appoint from their own number
a Publication Committee, consisting of the Secretary and two others,
whose duties shall be to determine the disposition of matter offered for
publication, except as provided in Section 17; to determine the expediency,
in view of the financial condition of the Society, of publishing any matter
accepted on its merits; to exercise general oversight of the matter and
manner of publication; to determine the share of the cost of publication
(including illustrations)- to be borne by the author when it becomes neces-
sary to divide cost between the Society and the author; to adjudicate any
questions relating to publication that may be raised from time to time by
the Editor or by the Fellows of the Society; and in general to act for I lie
Council in all matters pertaining to publication.

Section 3. Special committees may be appointed by the Council or
the Publication Committee to examine and report upon any matter offered
for publication.

Section 4. The duties of the Secretary include the preparation of a
record of the proceedings of each meeting of the Society in form for
publication; and the custody, distribution, sale, exchange or other author-
ized disposition of the publications.

Form of Publication.

Section 5. The Society shall publish a serial record of its work enti-
tled "Bulletin of the Geological Society of America."

Section 6. The Bulletin shall be published, for immediate distribu-
tion, in covered parts or brochu res, consecutively paged for each volume.
The brochures shall be designated by volume numbers and limiting p.i

4 ROLES RELATING TO PUBLICATION.

and each shall bear a special title Betting forth the ('(intents and authorship,
the seal and imprint of the Society and the date of publication.

The Bulletin shall also be published in complete volumes, with volume
covers, and each volume shall comprise the issue of a calendar year.

Sectiom 7. The brochures shall be classed as memoir brochures and
brochures of proceedings.

Section 8. Each memoir-brochure shall consisl normally of a single
memoir, or article, either accompanied by discussion or not; it may con-
sist exceptionally of two or more memoirs where the subject matter is
closely related.

Section 9. The proceedings of the annual, summer and special meet-
ings of the Society, prepared by the Secretary (including shor,t papers,
abstracts, etc.), shall be published as separate brochures as soon as may

be after these meetings.

Section 10. The proceedings of the annual meeting shall form the
closing portion of the volume for the year.

Section 11. The brochure containing the proceedings id' the annual
meeting shall contain also an index to the volume, paged consecutively
with the body of the volume; and it shall he accompanied by a volume-
title-page and lists of contents and illustrations, together with lists of the
publications of the Society and such other matter as may he deemed neces-
Bary by the Publication Committee, all arranged under a separate Roman
pagination.

M LTTEB OF PUBLK \TION.

^ in h.'. The matter puhlished in the Bulletin shall comprise ( I )

coiiiniunicat ions presented at meetings by title or otherwise; (•.') communi-
cations or memoirs not presented before the Society; (.*>) abstracts of
papers read before the Society, prepared or revised Eor publication by

authors; (I) reports of discussions made before the Society, prepared or

revised for publication by authors; (5) proceedings of the meetings of the
Society prepared by the Secretary; (•'>) plates, map-, ami other illustra-
tions necessary for the proper understanding of communications; (T) lists
of Officers and Fellows, Constitution, By-Laws, resolutions of permanent
character, rules relating to procedure, to publication and to other matters,

etc.; and (8) indices, title pages, and lists of contents For each volume.

Section 13. Communications making sixteen or more printed pages

of text, including figures, shall he puhlished as memoir hrochiires. Coin-

lications making less than sixteen printed pages maj he included in

t he proceedings brochures, or published as memoir brochures, at t he opt ion
of the individual ant hors : hut in the latter case the number of pages shall

RULES RELATING TO PUBLICATION. 5

not be less than eight and the additional expense ($6 per brochure) for
brochure covers and distribution shall be assessed on the authors.

Section 14. Abstracts, reports of discussion, or other matter purport-
ing to emanate from any author shall not be published unless it has been
either prepared or revised by the author.

Section 15. Manuscript designed for publication in the Bulletin must
be complete as to copy for text and illustration, unless by special arrange-
ment between the author and the Council or Publication Committee; and
the cost of any necessary revision of copy, or reconstruction of illustra-
tions shall be assessed upon the author.

Section 16. The Editor shall examine matter designed for publication,
and shall prepare an itemized estimate of the cost of publication, and con-
vey the whole to the Publication Committee. The Publication Commit-
tee shall then scrutinize the communication with reference first, to relev-
ancy; second, to scientific value; third, to literary character; and fourth,
to cost of publication, including revision.

For advice with reference to the relevancy, scientific value and literary
character of any communication, the Publication Committee may refer it
to a special committee of their own number, or of the Society at large, or
may call to their aid from outside one or more experts.

Questions of disagreement between the Editor and authors shall be
referred to the Publication Committee.

Section 17. Communications from non-Fellows shall he published
only by specific authority from the Council.

Section 18. Communications from Fellows not presented ;it regular
meetings of the Society shall be published only upon unanimous vote of
the Publication Committee, except by specific authority from the Council.

Section 19. Matter offered for publication becomes thereby the prop-
erty of the Society, and shall not be published elsewhere prior to publica-
tion in the Bulletin, except by consent of the Publication Committee.

Manner of Publication.

Section 20. The matter of each memoir published as a separate
brochure shall be classified by subjects, and the classification suitably indi-
cated by sub-titles; and a list of contents shall be arranged with reference
to the sub-titles.

Section 21. Proofs of letter-press, and, when necessary, of illustra-
tions, shall be submitted to authors whenever practicable; but printing
shall not be delayed, by reason of absence or incapacity of authors, more
than one week beyond the time ordinarily required for tin' transmission of
mails. Complete proofs of the proceedings of meetings Bhall be sent to

6 RULES RELATING TO PUBLICATION.

the Secretary; and proofs of short papers and abstracts contained therein
and exceeding one-half page in Length shall be sen! also to authors.

Section 22. Bach brochure of the Bulletin shall begin, under its
proper title, on an odd-numbered page bearing at its bead the title of
the serial, the volume number, the limiting pages, the plates, and the
• late of publication, together with a list of contents; each brochure shall
be accompanied by the illustrations pertaining to it, the plates numbered
consecutively for the relume; and .such brochure may, at the option of the
Publication Committee, contain an alphabetical index, provided the Bame
be prepared by the author, and paid for by him.

Section 23. The cost of proof correction in excess of five percent,
on the cost of printing may be charged to authors.

Section 24. Unless the author of a memoir objects thereto the dis-
cussion upon his communication shall be printed as the closing pari of
the brochure, with a suitable reference in the list of contents. In case
the author objects to this arrangement, the discussion shall be printed in
the proceedings.

Si;< iion •>:>. Each hrochure shall hi' enclosed in a cover bearing at the
head of its title-page the title of the serial, the volume-number, the limit-
ing pages, and the numbers of the contained plates; in its upper-central
pari a title indicating the contents and authorship: in its lower-central
part the seal of the Society: and at the bottom the imprint of the Society.
Volume covers shall correspond to brochure covers, with proper volume
designai ion on side and hack.

Section 26. The author of each memoir printed in hrochure form
shall receive thirty copies without charge, and shall be authorized to order
through the Editor any edition of exactly similar brochures at cost of
paper, press-work and binding; and no author's separates of the memoirs
published as brochures shall be issued except in this regular form.

Section 27. Authors of papers, abstracts, etc., in the proceedings
brochure shall have the privilege of ordering, through the Editor, al their
own cos! for paper, press-work, binding, and necessary composition, an\
number of separate copies, provided these separates hear the original pag-
ination, and a printed reference to the serial and volume from which they
are extracted.

9 ■ iios 28. The Editor shall keep a record of all publications issued
wholly or in part under the auspices of the Society, whether the same be
authors' editions of the memoir brochures, autnors' extracts from proceed-
ings, or any other matter printed from type originally composed for the
Bulletin.

I ion 29. The bottom of each Blgnature, and each initial page will
heai- a si -nat u re mark giving an abbreviated title of the Berial, I he volume.

KULES RELATING TO PUBLICATION. 7

and the year; and every page (except volume title-page) shall be num-
bered, the initial and sub-title pages in parentheses at bottom.

Section 30. The page-head titles shall be: on even-numbered pages,
name of author and catch title of paper, on odd-numbered pages, catch
title to contents of page.

Section 31. The date of publication of each brochure shall be the day
upon which the last form is locked and put upon the press.

Section 32. The type used in printing the Bulletin shall be as follows:
For memoirs, body, long primer, 6-to-pica leads; extracts, brevier, 8-to-
pica leads; footnotes, nonpareil, set solid: titles, long primer caps, with
small caps for author's name; sub-titles, long primer caps, small caps,
italic, etc., as far as practicable; for designation of cuts, nonpareil caps
and italics, and for legends, nonpareil, Roman, set solid; for lists of con-
tents of brochures, brevier, G-to-pica leads, a new line to an entry, running
indentation; for volumes, the same, except 4-to-pica leads and names of
authors in small caps; for indices, nonpareil, set solid, double column,
leaders, catch words in small caps, with spaces between initial letters.
For serial titles, on initial pages, brevier block caps, with corresponding
small caps for volume designation, etc.; on covers, the same, except for
page heads long primer caps; for serial designation, long primer; for
brochure designation, pica caps; special title and author's name, etc., long
primer and brevier caps; no frame on cover. No change in type shall he
made to adjust matter to pages.

Section 33. The paper shall he for body of volume, 70 lbs. toned
paper, folding to 16 x 25 centimeters; for plates, good quality plate paper,
smooth-surfaced, white, cut to 64 \ L0 inches for simple plates; for covers
smooth-surfaced, fine quality 100 lbs. light-buff manilla paper.

Section 34. The sheets of the brochures after folding and gathering,
shall be stitched with thread; single page plates shall be stitched with the
sheets of the brochure to which they pertain; folding plates may he either
gummed or stitched (mounted on stubs if necessary); covers shall he
gummed.

Section 35. Volumes, plates, and cuts in text shall he numbered in
Arabic; Roman numeration shall be used only in signature marks, and in
paging the lists of contents, etc., arranged Eor binding al tic beginning
of the volume.

Section 36. Imprimatur of Editor, on volume-title-page; imprimatur
of Council and Publication Committee, on obverse of volume-title-page;
imprimatur of Secretary, on initial pages and covers of brochures of pro-
ceedings. Printer's card, in fine type on obverse of title page.

8 RULES RELATING TO PUBLICATION.

Edition an i> Disi ttlBi HON.

Sectiom 37. The regular edition shall be 750 copies for the Society,
and 30 copies for authors. In case two or more authors contribute to
a memoir-brochure, the edition of thai brochure shall be enlarged bo as to
give each am hor thirty copies.

Of the 750 copies printed for the Society, a Dumber exceeding by
fifty the number required for immediate distribution shall be bound as
brochures; the remainder shall be bound as volumes.

Se< i ion 38. Each brochure shall be forwarded promptly on publica-
tion to Fellows. Correspondents and Patrons, and to such other regular
recipients as shall elect that mode of distribution. On completion of a
volume it shall be forwarded, in volume cover, to other regular recipients.

S i iion 39. of the undistributed residue LOO copies shall be reserved
t" be sold to 1'ellows subsequently elected; the remainder shall he held
for -ale.

- ctiom 40. The Bulletin shall be sent free to Fellows of the Society
noi in a r rcai-s for dues more than one year, to Correspondents and Patrons,
and also to exchanging institutions.

Sectios 11. The priee of the Bulletin shall* be as follows: Volumes
to Fellows at an advance of about fifty per cent, on the cost (including
incidentals, distribution, etc. ). t he amount being a mult i pie of fifty cents.
(The price of Vols. I and II is, to Fellows. *■!..">( >. prepaid). The fixed
price to libraries and institutions is *."> per volume; to non-Fellows *10.
Thi' price of each brochure shall he a multiple of five cents, and shall he.
to Fellows, an advance on cost of about L50 per cent., and to the public,

an advance on cost of about 400 per cent.

New York Botanical Garden Librar

3 5185 00257 9215

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