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1 2 3

GEOLOGICAL MAP

OF THE

NITED STATES

COMl'lI-KD BY

C. H. HITCHCOCK,

NEW YORK:
PUBI.ISHF.I) BY JULIUS BIKN, iS PARK PLACE.
i88t. '

■-, it

GEOLOGICAL MAP H

:c>>

\,^

ov 11 II-;

UNITED STATES.

(■(•MI'II.KI) 1!V

C. H. HITCHCOCK,

NEW YORK:

rur.i.isiiKi) v.\ iri.iL's iuf.n, is i'ark i'lack.

i88:(.

• • ••« •• •••*

• •••«• •• •«* ••

I k • t 1 I

• , , at!
I I • > . - - .

*i» •••'till It

I 111

S t 1 »
4 8 * >

• A « • ft

• • • •

■'

*• • •

• ••■ • • • •• ••• •••• •••• • ••• "• ••

•• •• • • » •

GEOLOGICAL MAPOFTHE UNITED STATES,

COMPILED HV

C. H. HITCHCOCK.

■'

Since printing the pamphlet, we have been enabled to
color approximately the outlines of the Eocene and Mio-
cene in Florida, as furnished by Prof. E. A. Smith, the
details to be published in the American Journal of

SciKXlE.

« «

<;. M. DAWSON,
C. E. DUTTON,
S. F. KMMON'S,'
W. .M. FONTAINE,
G. K. GILBERT,
ARNOLD HAliUE,

.1. r. LKS1.1^\,
S. S. I. VON,

w. J. .M((;kk,

J. S. NEWBERRY
RICHARD OWEN,
J. W. POWELL.

C. A. UHM J<J,

R. V. WIIITEFIELI:),

J. D. WIIITNEV,

A. WINCHELL,

N. H. WINCHELL,

A. 11. WORTHEN.

All the published reports by the United States and
State Goverments, as well as the minor publications enu-
merated in Frederick Prime, junior's catalogue, have
been made use of as far as practicable.

/. ' *. - .

,• •• ,•• ••

• • •• ••••••

• • • .• • • • ••»

» • * . * * • •

* •• * • • • • •
I • • • • • •

• • • ••

• • • a • •

." ••'• ••

• <■ • • •• • I

••• • •• •,

• ••■ •••••»

• • • • • • •

. • •-#•

GEOLOGICAL MAPoFTHE UNITED STATES,

COMPILED BY

C. 11. HITCHCOCK

The object of this pamphlet is not to draw geological
conclusions from the materials now brought together, but
to state briefly upon what authority every part of the map
has been based.

In its compilation the following geologists have been
consulted, and I am indebted to them for valuable aid
rendered :

ROBERT BELL,
WM. I-. BLAKE,
S. B. BUCKLEV,
THOMAS CONDON,
O. M. COOK,
K. D. COPE,
E. T. COX,
JOHN COLLETT,
J. D. DANA,
C. M. DAWSON,
C. E. DUTTON,
S. r. i';M>H;XS,
\V. M. KONTAINE,
G. K, GILBERT,
ARNOLD I [AGUE,

JAMES HALL,
E. V. HAVDEN,
E. W. inLi;ARD,
E. S. HOLMES,
E. E. HOWELL,
T. STERR\' IH'NT,
\y. C. KERR,
CLARENCE KLNCi,
H. C. LEWIS,
j. W LESLEY,
S. S. LVON,
W. J. McGEE,
J. S. NEWBERRY.
RICHARD' OWEN, ,

J. w. 1'owi:ll.

R. I'UMPELLV,

W. B. ROGERS,

J. .M. SAFEORD,

A. R. C. SELWYN,

N. S. SilALER,

E. A. SMITH,

J. J. STEVENSON,

G. C. SWALLOW,

W. Ll'IIAM,

C. A. WHITE,

R. 1'. WHITEEIELD,

J. D. WHIINEY,

A. WINCHELL,

N. H. WINCHELL,

A. IL WORTHEN.

All the i)ublished reports by the United States and
State Goverments, as well as the minor publications enu-
merated in Frederick Prime, junior's catalogue, have
been made use of as far as practicable.

Tlie effort, to prepare this map took shape nearly fifteen
years since. At first we proposed to issue separate niajjs
of the different States and territories, using such scales of
dimension as best suited the perfection of the facts and
the size of the districts. These maps were to have been
published in atlas form, accompanied by descriptive text,
prepared, when possible, by the authors of the respective
maps. In answer to our solicitations, many maps and
manuscripts made their appearance, some of which have
since been published ; but our desire for greater accuracy
of information and its accpiisition by tedious held-work in
New England prevented the execution of the original
scheme. Meanwhile we have presented to the public an
epitome of our materials: hrst, in connection with the
report of the Superintendent of the Ninth Census ; second,
in the report of the Commissioner of Mining Statistics ;
thirdly, in Walker's Statistical \tlas, 1874; and founhly,
upon a large scale for the exhibit of the Smithsonian Insti-
tution at the International Exhibition at Philadelphia in
1876. Prof. W. P. Blake assisted us in the (^reparation of
these f(jur editions.

We have now to announce the completion of our labors
in the publication of this geological map of the L^nited
States, by Julius Bien, of New York. The base used is
the Centennial map of the United States (edition of 1879).
drawn upon the scale of twenty miles to the inch. This
gives, when mounted, a sheet thirteen feet long and eight
feet wide. It is made for a wall map, and hence cannot
exhibit minute details of topography. The principal lakes,
rivers, railroads, cities, towns, railroad stations, mountain
ranges, and all the counties are represented. Prof. Blake
has prepared for us the coloration of California and por-
tions of Nevada and Arizona.

We have not yet a universally acceptable scheme of

■'

nomenclature for the formations, nor have ^rcologists agreed
as to the C(ilors which will most appropriately designate
them. Our endeavor is to employ those names of groups
which are in common use, with the frequent mention of
synonyms. The minute suodivisions of the New York and
other systems of classifications cannot be carried out all
over the country, and therefore many dit>iculties ol termi-
nology are avoided, since only the more general terms
need to be stated. The following table expresses the
classification adopted in the legend:
Quaternary.

Newer.

Middle.

Older.

o
o
u

•s

Laramie or Lignitic ^n-oup.

Cretaceous.

Jurassic and Triassic.

Permo-Carboniferous.

Upper Coal Measures, usually above the Pitts-
burg Coal.

Lower Coal Measures, including the Millstone
Grit.

Lower or Sub-Carboniferous.

Devonian |Catskill to Oriskany|,

Upper Silurian [Lower Helderberg to Oneida].

Lower or Cambro-Silurian [Lorraine or Hudson

River to Calciferous Sandrock].
Cambrian.

Huronian.

Gneiss of Atlantic slope, including Montalban,

and metamorphic Paleozoic.
Labrador or Norian.
Lauren tian.

•^ I Granite.

a' I Volcanic.

^ i.

Southern margin of the Eastern American ice

s'aeet : also, terminal moraines east and west
of Ohio.
The Quaternary includes recent rivei deposits, oceanic
additions to the Tertiary continent, desert sands, and
lacustrine deposits of the Far West. An attempt is also
made to show the course of the supposed glacial terminal
moraines, from Cape Cod to the Saskatchewan region.
The terms Pliocene, Miocene, and Eocene are essentially
synonymous with our designations of Upper, Middle, and
Lower Tertiary — the latter allowing more latitude of refer-
ence than the former. The Laramie group is represented
by itself, partly because of its importance, ana partly be-
cause of some disagreement as to its exact place in the
sei.es. Perhaps a twofold subdivision of the rest of the
Cretaceous might have been practicable. I^rominence is
given to the scverc'l members of the Carboniferous, because
of the economic importance of the Coal Measures. Recent
observations suggest the presence of several areas of the
Permo-Carbouiferous, both in the east and the west. The
evidence for it in Pennsylvania and West Virginia is less
satisfactory than in Texas, Indian Territory, Kansas, and
Colorado. The lower division of the Coal Measures ex-
tends to include the conglomerate at their base, and hence
to include a larger area than is actually underlaid by
workable coal. The Catskill group is taken for the upper
and the Orishany for the lower limit of the Devonian,
though there is a diversity of opinion as to the pro-
pria y of this restriction, especially as to the lower mem-
ber, which is very commonly placed with the Silurian.
The commencement of the Lower or Cambro-Silurian

* ■ V

\ ^

with th.> Calciferous Sandrock is generally acceded to
at the present day. Some prefer to write Siluro-Cam-
brian instead of Cambro-Silurian, as originally proposed
by Sedgwick, and quite extensively used by English geol-
ogists. The word Cambrian suggests a world of conten-
tion. Our representation (.overs the areas termed by
authors the Potsdam, Acadian or St. Johns, Keweenian
or Kewenawan, Lake Superior, St. Croix, much of the
Taconic, etc., besides various mica schist groups in New
England, and the itacolumites ot the Southern States.
There is not entire agreement in the reference of man}-
eastern terranes to the Huronian. Certain areas in Mich-
igan and Wisconsin might be correlated with the gneisses
of the Atlantic slope, commonly called McMitalban ; but in
the present state of opinion it has not seemed best to
separate them from the Laurentian. 1 understand the
Montalban to represent gneissic areas in the upper part of
what might very naturally be called Laurentian. They
underlie the Huronian and seem to be unconformable
with the Laurentian beneath. Some authors regard the
Montalban as meiamorphic Silurian and Devonian, others
aspost-Huronian but preSilurian. The term Upper Lau-
rentian was originally applied to the Labrador or Norian
series. This group is represented in Canada and New
York by a special color, in accordance with the definitions
of Logan and Sterry Hunt. In the West, the term Lau-
rentian includes cverx thing below the Huronian. Granite,
essentially eruptive, is distinguished by a separate color
so far as possible. Much more of it remains to be sepa-
rated from the Laurentian. The modern volcanic ejec-
tions of the West are distinguished as a class without
subdivision. The trap division is not represented at all.

It is possible to give nii.ch fuller details of the Pale-
ozoic formations in the Appalachian region, but not in

the West; and. thcrelorc, for the sake of uiiiformitv, the
smaller series have beei. merged in the larg-er. In the
following- text, also, certain special variations in the sii^nih-
cance of the colois will be mentioned.

After reducinsr the maps of adjacent States, by different
authors, to our scale, it often ai)pears that the colors will
not fit each other. This may be due to differences of
opinion as to the proper limits of the several g-roups or to
incorrect maps. To harmonize such differences is a mat-
ter of irreat difficulty and often impossible, and has led us
to adopt the following principle for our guidance. We
assume that each geologist understands his own territory
better than any one else, and therefore follow his division
lines to his boundaries, where a forced connection is made
with his neighbor's delineations. If great incongruities
are occasioned by this course, a statement of the case will
be made in the following pages.

Objection is sometimes made to the attempt to prepare
a geological map of the whole United States, that over
large areas the character of the underlying formations is
not known, and that consequently the student is perplexed
by not knowing what is well determined and what is
hypothetical. Some suggest that w^here great uncertainty
exists. no attempt should be made to represent even what
is probable. I have in some cases left blank si)aces in the
entire absence of any attempt at exploration. In other
cases I have used a broken instead of a solid color, thus
enabling all to perceive at a glance where the structure
has not been worked out satisfactorily. In some S])ecial
cases the difificulties of coloration a/e particularly de-
scribed.

With these general remarks we proceed now to state
specifically what authorities have been used for the repre-
sentation of the geology of all parts of the map. Vet we

have not space enouj^h to acknowledge many of the
smaller items of information kindly furnished by our corre-
spondents.

DOMINION OF CANADA.
Every possible facility for the acquisition of the latest
information about the distribution of the formations in that
part of Canada embraced in our map has been cheerfully
furnished by A. R. C. Sehvyn, the accomplished Director
of the Geological Survey. The sheets have been submitted
to him and his assistants: particuh rly Prof. R. Bell and
G. i\i, Dawson, and their suggestions of improvement have
been followed. In fact, Prof. Bell colored, with his own
hand, the x^gion north of the paleozoic basin, from Quebec
across to the Rocky Mountains. From Lake Winnipeg to
the Pacihc Ocean we follow the guidance of G. M. Daw-
son.

Logan's map of 1865 correctly represents the fossilifer-
ous groups from Quebec to Lake Superior. For the east-
ern townships region, the views of Sterry Hunt and Sel-
wyn are adopted in placing the Lauzon and Sillery beneath
instead of above the. Levis, the latter containing many
primordial types of life. The Canadian extension of the
Vermont Green Mountains is referred to the Montalban
because it underlies the Huronian. East of Sherbrooke
P. Q., the calcareous rocks were referred to the Upper
Silurian by Logan. As they seem to merge into the Coos
and Calciferous mica schist groups of Vermont, and the
latter are by Dana referred to the Lower Heldcrberg, I
have represented their age south of Canada as doubtful. In
order to call attention to the existence of a gneissic scries
m Ontario newer than the Laurentian, though its place in
the column is unknown, we have r )lored the Hastings
group of Vennor the same as the Montalban.

1 1:

There is a diserepancy in the maps of the country be-
tween the Lake of the Woods and Red River. Bigsby, in
1842 yQiiar. Jour. GeoL Soc, London), described Upper
Silurian limestones in situ upon the west shore of the Lake
of the Woods. Prof. Hind, in i860, extends this group of
fossiliferous rocks westerly and southerly into Minnesota,
to the latitude of 46°. Logan's maps differ. The small one
makes a broad strip of Devonian extend entirely through
Minnesf)ta to connect with the exposures of this age in
Iowa. This is accompanied by a br(.)ader area of the
Trenton from Red River to Lake of the Woods, and to Lat.
45°, where its width is much diminished and is continuous
into Iowa. The larger map has the Devonian terminate
abruptly about twenty-five miles south of the international
boundary ; and the Trenton has less width, reaching to
Todd and Douglass counties. West of the Lake of the
Woods is an area of Niagara, continuous thence along the
international boundary to Rainy Lake.

G. M. Dawson, in the Boundary Survey, colors the en-
tire area between the Lake and Red River as Paleozoic.
Professor Bell divides this area midway between these
points, giving half to the limestones and half totheLauren-
tian ; and thinks the supposed fossiliferous outcrops about
the Lake of the Woods consist of transported lioutders.
Our representation shows all of northern Minnesota as un-
certain — by means of broken colors — and disposes of a part
of the troublesome area by giving the limits of the former
glacial extension of Lake Winnipeg — called Lake Agassiz
by the Minnesota Geological Survey. From Lake Traverse
to the mouth of the Saskatchewan, there is hardly a rocky
outcrop — so that the use of the yellow color for the Qua-
ternary is eminently appropriate. To the north of the Sas-
katchewan, where the ledges are plenty, the limits of the
lake are also shown by suitable markings. Many of the

enormous Huronian areas east of Lake Superior are shown
in broken colors, because their limits have not yet been
worked out. Concerning the representation of the coun-
try west of the Rocky Mountains, remarks will be made
further on in the mention of Washington Territory.

NEW ENQLAND.

The compiler is alone responsible for the delineation of
the geology of New England— making use of all the offi-
cial reports, so well known, combined with personal field-
work. The map, when mounted, well shows the difficulty
of calling the New England gneisses by other names than
are commonly assigned to them from Alabama to the
Highlands of the Hudson, /. i\, Laurentian with pre-Silu-
rian accompaniments. The range is a continuous one from
Alabama to Canada, consisting of gneisses, and bordered
first by the Cambrian sandstones, derived from the ruins
of the gneiss; thence by the great Appalachian Lower Silu-
rian limestone valley. If orography is determined by
stratigraphy, then the gneisses of New England are mainly
of pre-Silurian age. A contour or relief map would illus-
trate this position even more strongly than colors.

The typical Montalban rocks in New Hampshire under-
lie the Huronian ; and we understand the same to be true
of all the gneisses upon the Atlantic slope colored as dis-
tinct from the Laurentian. The Laurentian areas in New
England are usually ovoidal in shape, and of limited ex-
tent ; and in the [-ri.neval history must have formed a con-
geries of islands before the interspaces became filled by
the Atlantic gneisses. The more important of them are
Formations K2. K3, of Percival, in western Connecticut ;
Formations A and B of Percival in caste.n Connecticut,
with their respective continuations into M issachusetts and
Rhode Island ; the Stamford granite and gneiss east of

Bennins^t-on. and. the Chester gneiss range of Vermont ;
gneissic areas east of Worcester, and underlying the Bos-
ton Cambrian basin in Massachus'jtts; the porphyritic and
Bethlehem protogene tracts in New Hampshire and the
coastal gneisses east of Portland in Maine.

Eruptive granites are distinguished in New England.
Canada, South Carolina, Cieorgia, and to a limited extent
in the far west. This is but a tithe of what will be sepa-
rated from the gneisses hereafter.

NEW YORK.
Our authorities for this State are mainly the published
map of the Geological Survey, and a manuscript map pre-
pared by Prof. R. P. Whitelield, showing the improvements
obtained under the directions of Prof. James Hall in the
Catskill mountain region and elsewhere, and exhibited to
the public in the American Museum of Natural History
at Manhattan Square. East of the Hudson. Prof. Dana's
recent ol)servations may authorize us to enlarge the Lau-
rentian area called Ki. by Percival. We accept his the-
ory of the superior position of the Westchester county
gneisses to the Laurentian ; but cannot yet see the way
clear to call them Silurian. Farther north we follow
Mather's view of the Lower Silurian age of nearly all the
rocks east of the Hudson, taking note, however, of certain
limited Cambrian exposures, and anticipating a greater ex-
tension of them hereafter at the expense of the clay slates
and talcoid schists once referred to the Taconic system. In
the Adirondacks an area of Labrador is given, as well as
possible, from Prof. Emmons' limits assigned to the hyper-
sthene rocks. Various hints suggest the future discovery
of Huronian and Montalban terranes within this elevated
district. Mather's reference of the Long Island division
to the Cretaceous seems to be confirmed, while the Tertiary
may also occur beneath the Quaternary.

NEW JERSEY.
i'n^i. G. H. Cook's latest reports are followed impli-
citly. He does not state definitely in his printed reports
which division of the Tertiary prevails in the low ground
next to the ocean, for want of outcrops ; but authorizes us
to call it ui)per Tertiary as far as Chesapeake Bay. The
former extent of the Hudson River valley out to sea is
shown off the coast of New Jersey bv the sub-marine con-
tour lines. What the age of the formations mav be in this
submerged district is doubtful. Perhaps the' discovery,
by Cook, of Devonian fossils in certain Cretaceous beds
as rolled pebbles may indicate the presence of Paleozoic
strata in this lost Atlantis.

PENNSYLVANIA.

The Second Geological Sur\c\- is in progress, and its
results have been utilized by us for the following counties:
hne. Crawford, Mercer, Venango, Lawrence, Beaver, But-
ler. Washington, Alleghany. Westmoreland, Fayette, Arm-
strong, Clari(Mi, Greene, Fulton, Blair. Huntington, Adams,
York, Lancaster, Lehigh, Northampton. Daui)hin. Lebanon,
Northumberland, MuaUmi; Union, Snyder, Pcrrv, Clinton.'
Lycoming, Sullivan, McKean. Tioga, and Potter. Else-
where Rogers' map has been followed, and made to tit the
new coloration somewhat arbitrarily. The members of
the survey differ in their estimates of the age of the crys-
tallines along the Susquehanna. Frazcr's maj) of the gneis-
sic areas is so unlike that of Rogers, and of Tyson in iMary-
laiul. that the forcing of a connection between them is less
lelicitous than usual. It seems to us as if the lower Car-
boniferous group has too great an extension in the north-
eastern part of the State. uiK)n which the Second Survey
liave not yet i-eported. If the CatskiU sandstone were

distinguished upon our map, it would display the contuiu-
ation of all the Carboniferous synclinals into New York.

MARYLAND, DELAWARE, VIRGINIA, WEST

VIRGINIA.

No chanj,^es have been made in the delineation of Mary-
land and Delaware since the publication of the Census
maps. For the Virginias we have had. first, the use of Prof.
W. B. Rogers' manuscript ma]); second, the i)ublication
of the same upon a small scale in the report of Maj. Jed.
Hotchkiss ; third. Prof. Rogers' note> m Macfarlane's rail-
way guide; fourth, letters from Prof. W. M. Fontaine, of
the University of Virginia ; and fifth, the Virginias h\ Maj.
Hotchkiss. The railway guide gives us the reference of
the Fairfax gneiss areas, west of Richmond, and from Lib
erty to near Lynchi)urg, to the Laurentian ; and the Meso-
zoic areas south of Richmond. Prof. Fontaine named for
us the Laurentian west of Lynchburg and Amherst ; and
furnished us a tracing showing the Huronian limits from
the Potomac to Willetts mountain. Subsecpiently he writes
that these limits may be extended farther, viz., "the three
counties of Floyd, Carrol, and Grayson are ccmiposed of
metamorphics like those fcjund composing the Blue Ridge
further north; c g. at Harper's Feny. Hence they are
Huronian, if there is any Huronian in the Blue Ridge
ranges. The line of junction of the jnetamorphics and
primordial rocks is to be found almost always, if not always,
just along the sf)utheast foot of the ranges called Pilot,
Poplar-Camp, and Iron mountains. The metamorphics
are hydro-mica and chlorite slates, sometimes with cpidote ;
some hornblende schist ; a great deal of felsite, sometimes
with copper ; also a singular gneissoid rock, having shot-
like particles of bluish quartz, of a waxy lustre, etc. ^'ou
will note that the range of Iron mountain near Balsam

mountain liciuls south, while it dies clown in the orif^inal
southwest direction. The new ranjre, now called Iron
and Smoky, is, near White Top. certainly Huronian if
we have any in the Blue Rid^e."

This letter ajj^rees with a map of this neij^borhood by R.
O. Currey, made in 1859, and published in the Virginias
for April, 1880; though the term Huronian is not used by
Currey. It also seems to ajj^ree with the map of Professor
Kerr in the North Carolina geological report, whose two
Huronian bands correspond nearly with the position of
the Virginia areas as described by Currey and Fontaine.
Dr. T. Sterry Hunt, on the contrary, is (|uite positive
that these two bands in North Carolina should be referred
to the primordial, the eastern band extending into Georgia
to merge into the itacolumite or "principal gold region"
of the geological map published m White's Statistics of
Georgia. Our representation of these areas follows the
latter author for North Carolina, and no effort is made to
separate any of the Eozoic groups in Alabama and much
of Georgia.

THE ATLANTIC PLAIN.

Adjoining the coast from New Jersey to Florida, and
thence through the Gulf States, is a low, broad country,
sometimes called the Atlantic plain, underlaid by Cretaceous
and Tertiaiy beds, which are commonly concealed bv the
Quaternary. It is most perfect in its devel()i)ment in the
Gulf States, where the upper Cretaceous line mav be sev-
eral hundred feet above the sea: to the north of Georsria
the rivers wind thi-ough marshy districts after leaving the
crystallines. It is not dititicult to see that they are drowned
lands, and entirely submerged east of New York, save the
islands Long, Block, Martha's Vineyard, etc. The plain
is traceable by soundings to join the Great Banks of New-

fouiullaiul, and the fishcniR-ii constantly l)rinfr in Teitiar\-
fossils from this ])lateau cast of Ca|)c Cod. The forma-
tions do not skirt the land roncentricallv over this entire
plain, as several anticlinoria aiul svnclinoria are easilv
made out. The first basiti is in Georji^ia, the second in
South Carolina, the thirJ in the southern part of North
Carolina, tin- fourth in North Carolina, merjLjinti;' into that
depression into which the James, York, and Potomac rivers
flow, inakinj^ Chesapeake Bay. Because of the lowness of
this land, the formations are not well defined ; and ue color
them, as seems best, after studyinjj^ Tysori's map of Marx-
land, Roi^jers", of Virj^^inia, Kerr's, of North Carolina, Tuo-
mey"s, ol South Carolina, Lvell's (^1845), ^' Cjeorj^ia.
Florida is represented as wholh- Quaternary ; but Conrad
has described Eocene fossils from its northern portion. Mil-
i^'ard has distiny;uishcd himself bv the patient unravelling;'
of the embayment of the Mississi|)pi vallev, includinj.j the
demonstration of a a^reat elevation of Lower Louisiana since
the Tertiarv ; and we re<^ret that we cannot present all his
subdivisions; enouj^h is <ri\cn, however, to illustrate his
views.

The narrow strip of Ouaternarv between this Atlantic
plain and the crystallines shown, from North Carolina to
Mississip])i, and. probablv, not entirelv exhibited, has been
su^p^ested by Tuomev to have bee 1 derived from the
meltinj^ of an ice-sheet covering' the crvstallines of the
more southern Atlantic mountains. The beds are the same
as the Oran"-e sand of Hilirard.

THE OAROLINAS, GEOiiaiA, ALABAMA.

The reports of Emmons, Ke;., Tuomev, Lieber, Little,
Smith, etc., ha\e been carefuUv studied for the solid rocks
of these States. The Taconic rocks of North Carolina,
clay-slates of South Carolina, also the mica, talcose, and

itacolumitc scries ..f Lwhvv arc all ranked as Cambrian
matching- the rocks thus dcsi-natcl by Little and Smith
in Geor^na and Alabama. Most oi flu- i^neiss in these
States is placed with our Montalban— pre-Huronian—
without attempting to separate the true Laurentian from
it. The eruptive j^ranites of South Carolina are jrivcn
after Licber, w ho seems to have understood correctly the
mutual relations of all the crystallines. More Iluronian
terranes remain to be distin«ruished in this rej^ion.

OHIO, INDIANA, ILLINOIS, KENTUCKY, TENNESSEE.

Nothinjr can be better than the maps of these States by
Newberry, Owen, Cox, CoUett. Worthen, Shaler. and Saf-
ford. If there is anything in our map unlike what has been
published in these several districts, it is because of si)ecial
informati(m furnished expressly for us by these gentlemen.
Professor Collett has revised for us the boundaries between
the upper and h)wer Coal Measures for Indiana and lUi-
nois, and designated a small Permian area, adding his
opinion that the whole upper part of the Coal Measures
ought to be called Permo-Carboniferous.

Upon an outline-map of Indiana recentlv |)ul)lished by
Prol. Collett, certain features are differentlv delineated
from our coloring. I^e does not carry the Upper Silurian
bridge across the western third of the State to connect
with the same strata in Illinois. Our coloring was bused
upon the detailed statements of counties in R. Owen's
report, and is certainly to be depended upon as far as Rens-
selaer. The gap between is entirely covered by drift-depos-
its, so that the broken color is ajjpropriate for this missino-
link. The precise northern extent of the Lower Carbonif-
erous, next Illinois, and the boundary between the Devonian
and Upper Silurian in the northern part of Indiana are, as
yet, only conjectural. Collett cuts off the si)ur of the Coal

Measures nuulc to reach Templeton. aiul elDiiijates the
projection of the same into Munroe County more than we
have (lone. Our outline was derived from a studv of
Professor Cox's report.

MICHIGAN.

Winchcll's and Rominj^er's maps of the lower peninsula
are (piite complete. Fumpelly's and Brooks' maps are
used for the upper peninsula. Brooks recojj^nizes the
Montallian of the East in the upper part of the Laurentian,
which is left uncolored upon the Michijj;an i)ul)lished map.
It extends into Wisconsin, l)ut is not separated from the
Laurentian upon our sheet; neither are the formations
XIX, XX, XXI, n-cofrnized by Brooks, as like the New
Hampshire Coos group, shown distinct from the Huro-
nian.

WISCONSIN.

The nivriad details of Chamberlin's ma|)s cannot he
reproduced upon our scale, hut are generalized by us
without intentional deviation. To Chamberlin and Irving
we owe a late representation of a considerable Huroiiian
area, reaching from Miciiigan nearly half way through
Wisconsin, not vet published officially. The Kewenawan
rocks are i)laced under Cambrian colors, since it is shown
to be post-Huronian, while older than I'otsdain.

IOWA, MISSOURI, ARKANSAS.

The maps of Mall and White are followed for our guid-
ance, with an improvement of the nuitual limit ot the
Lower and Ui)per Silur-m sent us by W. -I. McGee; and
it was found necessary to shift the line dividing the u|)per
and lower Coal Measures, in in'e,- to match tlie corre-
sponding horizon in Missouri,

«9

Professor Swallow coiniminicatal to us a mamisciipt
map of Miss<.iiri many years since, which proves to be in
entire -A^^vvvmcnf with the later publications .)f Broadhead
and Huinpelly. As the later publications did not cover
the entire territory, there are considerable areas in our
compilation <riven to the public uow for the first time.

The data for Arkansas have been compiled by Prof.
Richard Owen trom the reports of his brother D. D.
Owen, with slij^ht emendations aloii.,^ the Mississippi valley,
taken from Humphrey's and Al)bot's llydrolo^ry of the
Mississipi.i, and the enlarj^aMiient of the Cretaceous in the
southwest part. As is well known, the Coal Measures of
Arkansas are only just above the Conj^Iomerate or Mill-
stone ^rit.

KANSAS, TEXAS, AND INDIAN TEERITORY.
The latest map of Kansas was published bv Professor
B. F. Mud-e in the report of the State AjrHcultural
Society for 1878. Fie had the advantajre of several years-
work in collecting fossils for the Pcabody Museum of
Vale Colleire, in addition to two years' official employ
by the State, and his conclusions are unlike those of his
predecessors and nei.irhbors, thouj,di. probably, nearly cor-
rect. He throws out the Trias alt<)<rether, believing that
the red beds of Hayden and Newberry, with the accom-
panying gypsum, belong to the lower Cretaceous, and
draws the west line of the Permian southwest to strike
the northwest angle of Indian Territory. As this view
is not acceptable to the other geologists named, I Iiave
shown a restricted area of Trias with a broken color.
giving portions of it to both the Cretaceous and Per-
mian. Except, so far as is recpiired to be consistent with
the above rendering, there is no variation in the represen-
tation of the rocks in Indian Territorv and Texas from

the last ctlihon of o.ir United States map in Walker's
Atlas. The reference of the Llano Estacpcio to Creta-
ceons is (.pi)ose(l by Marcou, wlio reu^ards it as Jurassic.
South of Kansas, the boundai'v between the upper antl
lower Coal Measures is entirely conjectural.

Professor Mudsj^e refers lar^'-e areas of Kansas, particu-
larly the northwest jjortion, to the I'liocene. This is at
variance with the color of eastern Colorado by Hayden,
who represents the Laramie groui) as impinsj^ing ajramst
Kansas. Being unable to i,nve the i)roper boundary be-
tween these groups. 1 have allowed oach to extend to its
State line, inserting at the northwest angle an indehnite
area of the middle Tertiary, upon the autli(»rity ot Prot.
l*;. D. Cope.

MINNESOTA.

Prof. N. H. WincheU >as patiently answered numerous
cpiestions concerning the Minnesota focks; and he regards
the present coloration as j)rovisional. We get, however, a
great improvement over the delineations ot the earlier edi-
tions. The use of Lake Agassi/ has been already men-
tioned. No systematic explorations of the northern [)()r-
tions of the State have been made: and the colors are
broken, where the compiler would have prelerred to
leave a blank space, after reading the reports ol School-
craft. Nicollet. Owen, Logan. Dawsor, Bell. Hind, aiul
WincheU. W'rv few ledges occur, the countrx being cov-
ered b\- drift. The areas of Silurian. Dexonian and Cam-
brian east of Lake Agassiz may possibly ha\e no better
tenure than the presence of erratic blocks derived bom
the northwest. Professor Bell has described mimilely sev-
eral bands of the Laurent ian and Iluronian along \\\v
international boundaiw b'om the Lake ol the Woods 1o
Lake Superior, and these are made to extend lar into

iMinnesola. Tlic Vermilion Lake terranc is traced across
to Alexandria. The Lanrentian is contined to the nor-
thern part ol the State; or, at least, the reference of

the iiianite and

i^neiss ahuii;- Minnesota ri\cr to this

series is donbtfiil. The Lanrentian and Huronian rocks
occnr in oval patches in Minnesota, as in Michi.^-an and
Wisconsin, rather than in one hn.ad stripe, vet niakin,ir an
Eozoic i)roniontorv reachin,;^ nearly thronijh the State,
the counterpart of the Adirondack peninsnla in New ^■ork.
Abrupt connections in the colorini,r between Minnesota
and Canada represent dilferences of opinion as entertained
bv the respective ^ovennnent ,<;-eolo,t;-ists. One of the
Minnesota areas of Huronian reaches to Taylor's Falls on
the St. Croix, and is su.y;,i,a"sted by Winchell as the con-
tinuation ot the same rock a tew miles distant in Wiscon-
sm. Only a thin coveiiii;^- of I'otsdam conceals it between
the known outcrops. The (piart/ites. etc.. of the i)ipestone
region are rejrarded as Potsdam. Ouite an CAtensive area
of {juartzite <,nieiss and granite is covered by the Cretaceous
in the southwest part of the State. If it were possible to
use both the pink and <,n-een colors lor the same area we
should do so here, as the country is essentiallv a Creta-
ceous ])lain showiiiij: the crystallines where it has been
deeply cut by rivers. Winchell lestricts the Fotsd.im to
narrower limits than those represented (after Belli wl. en-
it passes into the Dominion adjoininij^ Lake Superior.

NEBRASKA, DAKOTA, WYOMINa, MONTANA.

The foundation to our kuovled^e of these districts,
was ^-iven us by Ilayden in the map accomjjanvini^ the
Reynolds expedition, and the final report upon Nebraska.
The changes consist in callini;- the Lignite Tertiarv Lara-
mie, i^dving some data from the notes of E. S. Dana and G. B.
Grinnell, forthe Yellowstone Army Exiiedition. and from the

Black Hills map ot Newton, prepared under the direction
of J. VV. Powell. Prof. Havden's maps and repoits have
afforded us the principal data for the delineation of the
immense areas of Wyoming- and Montana. Permission
was given iis to cop)' from several of his maps in advance
of their publication.

In Hayden's map, illustratm^ the Revnolds expedition,
the whole of Montana is colon.'d with much precision.
That which lies east of the crvstallines has been modihed
considerably by Hayden's later ex])editions. He ijives
notes of the rocks at Jefferson, Helena, and at the Forks,
also panoramic views, but ver\- scanty maj^s. We there-
fore follow the Reynolds map, save whciC it has been
differently described in later publications. The maps, in
the reports of 1877, 1878, for the Yellowstone Park and
farther south, are of great value for the northwest part of
Wyoming. In the earlier map, all the volcanic and crys-
talline rocks were not distinguished from each other; and
hence the use of a similar color for the entirelv unexplored
region of the west part of Montana and the east part of
Idaho must be regarded mereh- as a cover for ignorance.
The principal part of Wyoming is likewise taken from the
Reynolds map.

GOVERNMENT SURVEYS OF TERRITORIES.

The elaborate (geological mai)s of the Fortieth Parallel
Survey under Clarence King; of Colorado and much of
Wyoming under Prof. F. \'. Flavden ; of the Geographical
and Geological Surveys under Lieut. Wheeler, espcciallv
in New Mexico, Arizona, Utah, and Nevada; of the vari-
ous reports prepared under tiie direction ol Major J. W.
Powell, as Button's High Plateaus of Utah, the Colorado
River and Uintah Mountains, the Henry Movmtains bv G.
K. Gilbert, the unpublished map of the Black Hills bv H.

Newton, etc., have all been consulted, and so far as prac
ticable transferred to our sheets.

For New Mexico the data have not been so complete.
Our sources of information are J. Marcou's Pacific Railroad
and other reports, 1857; Prof. J. S. Newberry's report in
connection with the Macomb Expedition ; annual reports
by Prof. E. D. Cope and H. Loew to Lieut. Wheeler,
1874; the extension of the coloring? of Hayden's Colorado
atlas for about hfteen miles into the territory ; and Prof. J.
.T. Stevenson's observations made for Lieut. Wheeler, in a
tract south of the north line of New Mexico to hit. 35° 15',
and between loui;. 104" 15' and 106^. Cope and Stevenson
agree that the Carboniferous strata east of Santa Fe should
be referred to the Coal Measures rather tlian the Lower
en- Sub-Carboniferous ; and it is likelv that much of what
we have referred to the Lower Carbonifenuis in the south-
eastern part of the territory and in Texas is of the same
age. Prof. Stevenson rtnds gyi)sum beds, similar to those
in the Indian Territory and referred to the Tri;'.s, appar-
ently situated in the Dakota group of the Cretaceous ; and
thus suggests a problem for future study, analogous to
that propounded by Mudgc in Kansas, lie also has de-
fined for us the eastern limit of the Laramie gnjup, bring-
ing it to the Raton Mountains to the southeast of Trinidad,
Col. The delineation of the northwest i)art of Arizona
and of southern Utah was taken from tlie maps of the
Wheeler Survey. Since then Messrs. Powell, Howell,
Gilbert and Duttcm have fashioned elegant relief majis of
the same regions, |)iesenting differences in detail from the
the origin.al Wheeler sheets. I have followed the later
authorities in the coloration of the volcanic masses in
N. W. Arizona, and in minor changes about the Acpiarius
plateau in Utah. The Permian in Arizona is given ap-
l)roximately from information furnished by C. D. Walcott.

The Huronian is ^-iven for the Black Hills, but not tor
any other ])art ot the territories, although supposed bv
Kin^ to exist extensively in them, especially in the more
eastern portions. North of the Fortieth Parallel Survey,
in Wyomino- and Nevada, are extensive blank areas, for
which we can hnd no data of representation. It would
have been better jierhaps to leave a i^reater ])art of
southern Nevada in the same condition. In Western
Nevada, California, Orci^on, Montana, and Idaho, the tint
for Lower Carboniferous is intended to sij^nifv Paleozoic
strata in general, though the Carboniferous is well defined
in Northern California. Likewise the older Tertiary tint
in the same State signifies Tertiary strata of anv age.

CALIFOB,NIA.

The California portion of the map is colored from mate-
rial furnished chieHy by Prof. VVm. P. Blake, using as a
basis his geological map of May, 1857, in the fifth volume
of the Pacific Railroad Reports our census maps, and the
results of recent explorations.

The crest of the Sierra Nevada consists mainlv of granite
and crystalline schists of pre-Silurian age, and believed to
be in part, at least, Huronian. For a part of the length of
the range these rocks are Hanked on the west bv Paleozoic
limestones, quartzites, and slates traversed bv auriferous
veins. Lower down the slope, serpentine rocks are fre-
quent, and there is a broad belt of slates, also auriferous,
referable to the Mesozoic period and believed to include
the Triassic and Jurassic formations. These formations
disappear at the southern end of the range, while at the
north they occupy a greater breadth, but are largelv cov-
ered by volcanic overflows. Upon the eastern side of the
range, especially from Mono Lake southwards, there is a
well-marked line of volcanic vents in the form of extinct

conical craters surrounded by lava streams. There are
also some extensive lava Hows on the opposite and western
slope, such as Table Mountain in Tuolumne County, and
upon the Upper San Joaciuin. The chiet area of former
volcanic outHow is, however, at the north, toward the
Ore^ron line, joining the vast volcanic area of the Cascade
ran-e. In this part of the State, Lassens Peaks, Shasta
Mcnmtain, and the Marysvillc Buttes are pominent volca-
nic centres.

The Cretaceous and Tertiary formations are largely
developed in the Coast M<nintains, both north and south
of San Francisco, with, also, limited areas of granitic rocks,
notably at Monterey, the Farallone Islands, and upon
Tomales Bay. There is also a broad belt of granite in
the foot-hills crossing the American River and extending
through Nevada County.

The Post Pliocene and recent formation cover a consid-
erable area of the State, especially in the central valley ot
the Sacramento, the San Joaquin, and the Tulares, and
farther south at the head of the Gulf of California, where
the dry bed of an ancient lake is now below the sea level.

Extensive areas of the State, especially at the north and
west, have not yet been explored geologically, and the
coloring upon such portions is hypothetical. Prof. New-
berry has given us the use of his notes upon the north-
eastern section along Pitt River, etc.

BRITISH COLUMBIA AND VANOOUVEE'S ISLAND.

G. M. Dawson sent us a maiuiscript maj) of British
Columbia, based upon his own and Mr. Selwyn's observa-
tions, which has since been published in ( he Canada re-
I'ort. The Tertiary, Cretaceous, and older intrusive rocks
are well defined. The most western Tertiary area is
Miocene, and is connected with the Washington terrane ;

determined to be of this aj^e by Prof. Newberry and
George Gibbs from the plants found at Bellingham Bay.
Dawson siiju^j^ests that Laramie beds may also occur in the
neiji;-hborhood, perhaps equivalent to the Cretaceous coals
of Vancouver. The little part of Vancouver's Island re-
presented is copied from the Canada maps by Selwyn and
Richardson. Most of the island is composed of crystalline
rocks. ])artly volcanic, and shown by Selwyn to be not
older than Carboniferous., We a])ply to them upon the
ma[) the indii^o lint j^iveu to the Carboniferous <^enerally
in the Rocky Mountain rej^ion. Another set of crvstalline
rocks occurs between lonj^itudes i2i° and 122'^. They are
repeated east of the Okinakane River; and I have ventured
to extend the same coloration as far east as the Kootenay
River, so as to correspond with the observations by Georj>e
Gibbs in Washiui^ton. Thev seem to be the metamorphic
rocks of the Coast and Gold rana^es. Between the two
areas mentioned, lies the Cache Creek ijroup of Selwyn,
much like the Vancouver Island series and including^ some
Triassic strata. This distinction into Cascade and Cache
Creek grou])S wasnot recognized bv Gibbs south of the in-
ternational boundarv line. East of the Kootenay, the
rocks are certainly Paleozoic, largely of Carboniferous age,
as determined bv Dawson, and the indigo tint is used to
represent them. The Crystalline rocks mentioned were
called granite and Huronian by Dr. James Hector, geolo-
gist of Capt. J. Palliser's expedition in 1857-60. He calls
the Rocky Mountain limestones east of the Kootenay
Devonian.

WASHINGTON TERRITOEY.

Tiic remotest corner of our map is one of the most dififi-
cult to color satisfactorily, and is based upon the informa-
tion turnished for Coluinliia by Sclwvn and Dawson.

Geofirc Gibbs. and Thomas Condon, State Geolojrist of
Orejron. It is supposed that the Olympic mountains con-
sist of the Vancouver Island crystalline njcks, which, in
their extension southwards, are much covered bv volcanic
overflows. It is thou<j;-ht best to use the pink Laurentian
tint for those crystallines, in the absence of in^-rmation of
the precise locality where the ancient <,nieisses commence
to occur. Condon furnished the statements for Macfar-
lane's railway j^uide for this territory, whence it appears
probable that Cretaceous rocks follow the Western border
of the Cascade rany^e, but certainly at Skookum Chuck.
Vashon Island, and Seattle. It is probable that this Creta-
ceous is bordered by the Eocene, and it is represented at
Steilacoom. Gibbs describes the Miocene in Fug-et Sound,
and finds it replaced by i^ranitic rocks, about twenty
miles up Skaf^it River, which extend thence entirelv across
the territory near the northern boundarv. We use the
jjink color to rei)resent them, though it seems probable
they are the equivalent of the later Cascade and Cache
groups described in Columbia. It is impossible for us to
draw the line between the older and newer crvstallines
here.

Similar difificulties i^resent themselves in attempting- to
color the formations in the eastern part of Washington.
Idaho, and ])arts of Montana. Excepting the small south-
ward extension of the Paleozoic tint east of Kootenay, I
have followed Hayden's map in the report of the Rev-
nolds expediti(m, but using a broken tint so as to express
the uncertainty existing as to the reference of the whole
area to the crystalline and igneous series. Certain mining
men assure me that the Coeur d'Alene mountains are gran-
itic : and others represent that the Salmon River region of
Idaho is only partially underlaid by the crvstallines.

The reference of an enormous territorv in Washinirton

to volcanic overflows is well established. AcxoRliiiL-- to
Condon an;l Le Conte those sheets overlie Miocene deposits
in the -;or<,^e of the Columbia through the Cascaile ranj-e.
Mrs. Rainier. Baker. St. Helens. Adams, Hood, and jei-
ferson. are some of the craters connected with the ig-neoiis
overflow.

OREGON.

For this re^non u e had a manuscript map colored for us
by Professor Condon ; and it was our lot to collect some ad-
ditional information, i)ersonally, in a (rip up the Columbia
River and across the Blue Mts. I understand that the
distinction between the volcanic and crystalline is not
maintained in the coast ran.<res. and that some of the Cre-
taceous rocks in the southwest corner may be crystalline.
The statements of local surveyors lead us to mark the rocks
of the Snake-River Canon as crystalline, rather than vol-
canic. Southern Idaho is j^nvcn from my own imperfect
notes.

TERMINAL MORAINES OF THE EASTERN AMERI-
CAN lOE SHEET.

Recent speculations about the existence of terminal
moraines, reachinj^r f,-om Cape Cod to the Rocky Moun-
tams, are so interesting ro us personally that we atten)pt
their delineation, following Chamberlin and Upham in
the main. Upham has furnished us the facts for Cai)e
Cod, Long Island, Iowa, and Minnesota, with suggestions
for Dakota. Chamberlin has outlined the course through
Wisconsin, Illinois, Indiana, Michigan, etc. Mr. H. C.
Lewis has given us the line through Pennsylvania, based
ui)on observations made in 1880, and intended only for an
approximation. The New Jersey line is gnven, as published
in Professor Cook's re])orts. The terminal moraine seems

(

to occur near the southern margin of the ice-sheet from
Cape Cod through to Ohio. From thence it is not known
whether the moraine is similarly located : and I have,
therefore, drawn the line indicating the extreme limit of
the ice marking, as furnished for Ohio by Prof. Newberry,
Illinois by Prof. Worthen, Missouri by Prof. Swallow,
Kansas by Professor Mudge. The moraines farthernorth
are called by Professor Cook " Moraines of Recession."

Remembering that flood-plains of sand and gravel are
intimately connected with terminal moraines, Tuomey's
conjecture that the belt of Quaternary skirting the solid
ledges from Mississippi through Alabama, Georgia, and
the Carolinas, is not unreasonable. From the writinirs of
W. B. Rogers and W. M. Fontaine, it seems that some
traces of the same Quaternary gravel may extend to Wash-
ington and Maryland, though those gentlemen differ in
their views of its ace.