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/B E R K E I E 'T\

LIBRARY

UNIVERSITY OF )
V CALIFORNIA /

UB&ARY

7HE pTORY OF THE 1^0 C Kg.

POPULAR GEOLOGY

J. DORMAN STEELE, Ph.D.,

FELLOW OP THE GEOLOGICAL SOCIETY, LONDON, AND AUTHOR OP THE
FOTJRTEEN-WEEKS SERIES IN NATURAL SCIENCE.

' Jjfy heart is awed within me, when I think
Of the great miracle which still goes on
In silence round me— the perpetual work
Of Thy creation, finished, yet renewed
Forever. " —BRYANT.

REVISED EDITION.

A. S. BARNES & COMPANY,

NEW YORK AND CHICAGO.

THE FOURTEEN WEEKS' COURSES

NATURAL SCIENCE,

J. DORMAN STEELE, A.M., PH.D.

Fourteei} Weeks iq Natural Ptylosopfyy, Price, $1.00

Fourteei) Weeks iij Cr^ernistry, " 1.00

Fourteei} Weeks ii) Descriptive Astronomy, " 1,00

Fourteeij Weeks ii) Popular Geology, (t 1.00

Fourteei) Weeks ii) Human Physiology, " 1,00

Fourteei) Weeks ii) Zoology, tl 1,00

Fourteei) Weeks iq Botany, " 1,00

A Key, containing Answers to the Questions

and Problems in Steele's 14 Weeks' Courses, " 1,00

4 PIORIC^L SERIES,

ON THE PLAN OF STEELE'S 14 WEEKS IN THE SCIENCES.

A Brief tyistory of the United States, Price, $1,00
A Brief tyistory of France, " 1,00

The same publishers also offer the following standard scientific
works, being more extended or difficult treatises than those of
Prof. Steele, though still of Academic grade.

Peck's Ganot's Natural Philosophy, Price, $1,25

Porter's Principles of Chemistry, " 1,40

Jarvis' Physiology and Laws of Healtfy " 1,20

Wood's Botanist and Florist, " 1.75

Cl^anjbers' Elements of Zoology, ". 1.00

Jljclntyre's Astronomy and tlje Globes, '( 1,20

Page's Elements of Geology, " .90

*** The foregoing are the prices at the Publishers' office. Any
volume will be forwarded by mail, on receipt of its price, with
one-sixth additional for postage and mailing fee.

STEELES' GEOL.

(£77

***

PREFACE.

rT^HE present work is based upon the same general plan
as the preceding ones of the series. The aim is to
make science interesting by omitting the minutiae which are
of value only to the scientific man, and by presenting alone
those points of general importance with which every well-
informed person wishes to become acquainted. The thing
is of more value than the name. A pleasant fact will be
recollected long after an unpronounceable term has been
forgotten. Therefore, only enough geologic nomenclature
is used to make the study systematic, to awaken a love for
the order of nature, and to afford a plan around which other
knowledge may crystallize.

The author is satisfied from his experience as a teacher
that pupils take no interest in the fossils which characterize
the various geologic epochs, except the few which are typi-
cal, unless they have access to a paleontological cabinet ;
in that case, they learn the names best by association with
the objects. If any attempt is made to name and illustrate
the fossils of any group, the limits of a small text-book per-
mit but a scanty selection, which is of little value in the

6 PREFACE.

identification of the fossils gathered by a class even within
the limits of that group, while to those outside it is useless.
Hence a school Geology should give only the general out-
lines, leaving to the teacher, with a copy of the survey of
his own State, and such collections as he may have or can
gather, to impart the instruction in local paleontology. The
author has sought to develop the following peculiarities :
(i) To give the general outlines of each subject, and only
enough of the details to interest without burdening the
mind ; (2) to develop the theories of the science thor-
oughly, and thus afford a clear idea of the methods of geo-
logic study as a basis for future progress; (3) to give
blackboard analyses of each subject for topical recitations ;

(4) by means of foot-notes to present the pupil with much
geologic literature, thus affording the information and cul-
ture of an extended range of collateral scientific reading
which would otherwise be within the reach of few pupils j

(5) to add the benefits of the " question and answer" sys-
tem to those of the topical method by means of a set of
thorough review questions at the close of the book ; (6) to
lead the pupil to a study of natural objects by treating very
fully the stones common in the Drift, and thus giving prac-
tical field-work at once ; (7) to adapt the book to all sec-
tions of our country by means of a clear presentation of the
typical New York system, and such modifications in the
text or foot-notes as will enable any pupil to make the ap-
plication to his own State.

It is hoped that this book will render the study of Geol-
ogy possible to young persons striving after self-education — -
to men of business, whose leisure allows only a limited ac-
quaintance with books, and to schools where the fresh buoy-
ant spirits of youth are now repelled by cold, formal state-
ments of purely technical truth. The author's most earnest

PREFACE. 7

desire is to awaken the thought and quicken the imagina-
tion of the pupil • to lead him to trace in nature the hallow-
ing and refining influence of Divine truth, and thus to
become one of that happy number who

" As by some secret gift of soul or eye,
In every spot beneath the smiling sun
See where the springs of living water lie."

The author would take this opportunity of especially
thanking the following teachers and friends, who have
aided him in this revision with many valuable suggestions,
as well as in the reading of manuscripts and proof-sheets :
ALEXANDER WINCHELL, LL.D., Professor of Geology, Sy-
racuse and Vanderbilt Universities ; JAMES HALL, LL.D.,
Geologist of the State of New York ; A. H. WORTHEN,
LL.D,, Geologist of the State of Illinois ; L. S. BURBANK,
A.M., Scientific School, Woburn, Mass. ; J. J. STEVENSON,
Ph.D., Professor of Geology, University of the City of New
York, and many others who have kindly furnished the rich
fruits of their experience.

The author takes great pleasure, also, in acknowledging
his particular obligations to Winchell's Sketches of Crea-
tion, Page's Chips and Chapters and Past and Present
Life, Foster's Mississippi Valley, and Agassiz's Geological
Sketches. Many of the drawings are copied from nature ;
the ideal views are taken from Figuier's World before the
Deluge. The Scenift Descriptions, which are a peculiar
feature of the book, are rhetorical flowers culled from the
broad field of geologic literature. The Glossary at the
close of the work is based upon standard authorities, and
will be found useful for reference.

8 PREFACE.

The author would recognize his obligations, in general, to
the following authorities :

Manual of Geology DANA.

Manual of Mineralogy DANA.

Geological Sketches AGASSIZ.

Methods of Study AGASSIZ.

Travels in Brazil AGASSIZ.

Elements of Geology HITCHCOCK.

The Mississippi Valley .... FOSTER.

Our Planet DENTON.

Chips and Chapters PAGE.

Elements of Geology . . . . PAGE.

The Earth's Crust PAGE.

Past and Present Life PAGE.

Medals of Creation MANTELL.

Wonders of Geology MANTELL.

The World Before the Deluge . . . FIGUIER.

Elements of Geology LYELL.

Earth and Man GUYOT.

Vegetation des Diverses Periodes du

Monde Primitif F. UNGER.

Recent and Fossil Shells . . . . WOODWARD.

Man in Genesis and in Geology . . . -THOMPSON.

Acadian Geology DAWSON.

Old Red Sandstone HUGH MILLER.

Testimony of the Rocks .... HUGH MILLER.

Popular Geology HUGH MILLER.

State Report of New York .... HALL.

State Report of New Jersey .... COOK.

State Report of California .... WHITNEY.

State Report of Illinois .... WORTHEN.

State Report of Pennsylvania . . . ROGERS.

Manual of Geology EMMONS.

Elements of Geology ANSTED.

Siluria (fourth ed., 1867) .... MURCHISON.

Sketches of Creation WINCHELL.

Prehistoric times LUBBOCK.

Manual of Paleontology .... NICHOLSON.

Early Man in Europe RAU.

The Popular Science Monthly.

SUGGESTIONS TO TEACHERS.

teacher will find Dana's Manual of Geology, re-
vised edition, of great value for reference in his studies.
In the eastern States, Hitchcock's works are of especial ser-
vice. The geological report of one's own State is essential
to furnish local information, and to enable the teacher and
pupil to identify the fossils they may gather. Geology can
be pursued without a cabinet, and yet a small collection of
the most common minerals is almost indispensable, and can
easily be obtained for comparison. Fossils are more diffi-
cult to secure. The teacher must rely mainly on his own
collection and exchanges with friends. Plaster casts of
typical genera and species can be purchased of Prof. Henry
A. Ward, of Rochester, N. Y. They answer all the purposes
of instruction, and in color and form can scarcely be dis-
tinguished from the original specimens. Information con-
cerning the cost of small cabinets can be obtained of the
publishers of this work. Geological excursions to river
channels, quarries, ravines, railroad cuttings, mines, gravel
beds, stone fences, &c., furnish most valuable information
and healthful recreation. A steel hammer of the form

10 SUGGESTIONS TO TEACHERS*

shown in Fig. i will be found most generally useful ; the
edges should be square, the socket

FlG* *' large' the handle strong> and the

P^ entire weight about two pounds.

,&d ,;E^SfifiSSii^^^ Rock specimens should not be

over three inches square and an

A GEOLOGICAL HAMMER. • 1 i • i 11 ill 1

inch thick, and should be neatly

trimmed. The locality of each specimen should be care-
fully noted and preserved.

The diagram at the commencement of each general sub-
ject forms an analysis of the topic. The author is accus-
tomed to have this placed upon the blackboard, and to
conduct the recitation from it, without asking questions,
excepting as occasion may suggest the necessity of addi-
tional information, or a closer investigation of the pupil's
knowledge. Questions for review are given in the Appen-
dix. It is suggested that teachers instruct their pupils to
assign such fossils as they may find, or have the privilege of
examining, first, to the sub-kingdom ; second, to the class ;
and third, to the order, but not to the family, genus, or
species, except in case of well-known fossils. Better satis-
faction will be given, and results secured, by doing so
much well, than by a vain attempt to teach everything in a
brief school-term.

Never let a pupil recite a lesson, nor answer a question,
except it be a mere definition, in the language of the book.
The text is designed to interest and instruct the pupil ; the
recitation should afford him an opportunity of expressing
what he has learned, in his own style and words.

CONTENTS

I. PAGB

INTRODUCTION, 17

II.
LITHOLOGICAL GEOLOGY, .

III.
HISTORICAL GEOLOGY, . 91

IV.
THE AGE OF MAN, 241

APPENDIX.

QUESTIONS, 257

GLOSSARY, . . .275

INDEX, 277

TN a valley, centuries ago,

-*- Grew a little fern leaf, green and slender,
Veining delicate and fibres tender,

Waving when the wind crept down so low ;
Rushes tall, and moss, and grass grew round it,
Playful sunbeams darted in and found it,
Drops of dew stole down by night and crowned it.

But no foot of man e'er came that way —

Earth was young and keeping holiday.

Monster fishes swam the silent main,

Stately forests waved their giant branches,
Mountains hurled their snowy avalanches,

Mammoth creatures stalked across the plain ;
Nature revelled in grand mysteries ;
But the little fern was not of these,
Did not number with the hills and trees,

Only grew and waved its sweet wild way ;

No one came to note it day by day.

Earth, one time, put on a frolic mood,

Heaved the rocks and changed the mighty motion

Of the deep, strong currents of the ocean ;
Moved the plain and shook the haughty wood,

Crushed the little fern in soft, moist clay,

Covered it and hid it safe away.

Oh, the long, long centuries since that day !
Oh, the changes ! Oh, life's bitter cost !
Since the useless little fern was lost.

Useless ? Lost ? There came a thoughtful man,
Searching Nature's secrets, far and deep ;
From a fissure in a rocky steep

He withdrew a stone o'er which there ran
Fairy pencillings, a quaint design,
Leafage, veining, fibres, clear and fine,
And the fern's life lay in every line !

So, I think, God hides some souls away,

Sweetly to surprise us the Last Day !

MARY BOLLES BRANCH.

" 3(n t&e beginning
createn rfje fjeatien anti tfte eartf)/

ANALYSIS OF INTRODUCTION.

I. ORIGIN OF THE EARTH ACCORDING TO THE NEBU-
LAR HYPOTHESIS.

II. SCENIC DESCRIPTION.
III. DEFINITION OF GEOLOGY.

i. THE SOLID SHELL.

IV. THE EARTH'S
CRUST.

V. METHODS OF
GEOLOGIC
STUDY.

2. PROOF OF

THE

INTERNAL
HEAT OF

THE

1. Temperature.

2. Artesian Wells.

3. Hot Springs.

4. Elevations and De-

pressions.

5 . Volcanoes.

EARTH. 6. Earthquakes.

1. NATURE'S LAWS UNIVERSAL.

2. SEDIMENTARY ROCKS.

3. TEACHINGS OF SED. ROCKS.

4. IGNEOUS ROCKS.

5. TEACHINGS OF IG. ROCKS.

6. FOSSILS.

7. TEACHINGS OF FOSSILS.

8. GLACIERS.

9. TEACHINGS OF GLACIERS.

a. Caves.

10. CHKONOLOGY.

b. Lake-bottoms.

c. Scottish Illus-

trations.

d. Italian Illus-

tration,

INTRODUCTION.

27ie Origin of the IZarlh's Crust according
to the Nebular Hypothesis.*— Our earth was once,
doubtless, a glowing star. In that far off beginning it
shone as brilliantly as do now the sun and the fixed
stars. In process of time it cooled from a gaseous to a
liquid form. It then assumed a spherical figure in
obedience to the same familiar laws of force which
round a drop of dew. Its atmosphere comprised not
only the gases that compose our present atmosphere,
but all the oxygen and carbon now locked in the rock
and coal masses of the earth, vast quantities of min-
eral matter vaporized by the fierce heat, and. in the form
of superheated steam, all the water which now fills the
ocean. The air, thus dense with moisture and metallic
vapors, rested on an ocean of fire. Ages passed, and
the earth, cooling as its heat became changed to other
forms of force, began to show on its surface patches
of solid substance, like the floating films that first appear

* See Fourteen Weeks in Astronomy, p. 282. THE NEBULAR HYPOTHESIS.

18 GEOLOGY.

on water as it passes into ice. These, gradually combin-
ing, formed at last a thin crust over the entire exterior.
This was, however, constantly rent asunder by eruptions
from the molten mass beneath. Huge crevices were
opened, and torrents of liquid lava, ejected from the
cracks and seams, were poured in fiery floods over the
scarcely solid crust. The surface, arid and burning,
bristled with ragged eminences, or was furrowed with
enormous clefts and cracks. But the earth had ceased
to shine as a star, and henceforth was itself to be
lighted and at last heated from other bodies. As the
globe continued to cool, a time arrived when the heat
was not sufficient to support the water in the form of
vapor. Under the tremendous pressure of the dense
atmosphere, the steam was precipitated, boiling hot,
upon the heated earth below. Reva£orized, it ascended
again only to be condensed and returned as rain. This
process, long continued, cooledjthe garth yet more rap-
idly. The crust, shrinking and cracking as it hard-
ened, became still more uneven with wrinkles and folds,
yawning gulfs and fissures. The hot rain falling on
the volcanic peaks, the torrents which poured down the
mountain sides and through the valleys, all combined
to dissolve the rock and sweep the sediment into the
deeper hollows. The crust had not yet attained the
consistency necessary to resist the pressure of the heated
gases and liquids. Hence, in this manner also, enor-
mous dislocations were made, whose folds and uplifts
with deep gulfs and belching lavas denoted terrific
convulsions. Thus a fierce conflict was raging between
fire and water. At last the water triumphed, and the
ocean became universal. A hot, muddy, shallow sea

INTRODUCTION. 19

surged round the earth from pole to pole. The internal
heat of the earth made the temperature uniform over
the entire surface, and hence there were no great oceanic
or aerial currents.

Astronomy teaches us the probable origin of our globe.
As soon as the crust began to be formed by the mingled
action of lire and water, Geology steps in to explain the
phenomena. In this vague and nebulous border-land the
two sciences meet. From that time we find that the
earth entered on a regular series of progressive revolu-
tions which gradually fitted it for the introduction of life.

The Mosaic Account of the Creationi^iwim l)
us that " the earth was at first without form and void ;
and darkness was upon the face of the deep." "With the
first motion of nebulous matter light was developed, or,
in the nervous language of Scripture— " God said, Let
there be light." Thus ended the work of the first day.*

* The word "day" is of course considered not as a literal day, but as sym-
bolical of a long period of time — ages, during which God was fitting this earth
as a home for man. The idea of exact days of twenty-four hoars each is neither
required by the original nor by the scope of the narration. The word "day"
itself is used in four senses in the description. The Christian fathers did not
interpret it as a common day. Augustine, in the fourth century, called the
days of creation " ineffable days," and described them as " alternate births and
pauses in the work of the Almighty— the boundaries of periods in the vast
evolution of the worlds." How glorious the idea which we here obtain of
God, as, through measureless ages in which he is rich, resting not, hasting
not, but slowly and by the steady operation of His own laws, He works out
to the finest detail His mighty thought of a world. Moses gives but the grand
outline of this creative act, an outline which Geology is filling up rapidly and
surely. The Mosaic account is a hymn, full of poetry and grandeur, n^t a
rlose. Ryflct1 ^ciftntiflfj rftr.nrfl of events. Yet its truths were inspired by the
same God who made the world. As such we receive the records of both rev-
elation and nature, and gladly notice their harmony in all their grand teachings.
As yet Geology is in its infancy, and we are often able only to suggest and
intimate what may hereafter be, firmly believing that God's truth must stand,
whether it be revealed in the rock or in the book.

W GEOLOGY.

On the second, the firmament or atmosphere was formed,
separating the clouds above from the sea below, which,
as the revelations of both the rock and the book teach
us, as yet covered the entire earth. This was the work
of the second day, that long era of cooling and consolida-
tion that separated the formless period of chaos from the
birth of the continents.

Scenic Description. — Let us imagine the scen-
ery of that primitive period. A dense atmosphere of
steam, metallic vapors, and sulphurous clouds which
conceals the sun, and through which the light of moon or
star never penetrates ; an ocean of boiling water, heated
at a thousand points from the central fire ; low, half-
molten islands, dim through the fog, and scarcely more
fixed than the waves themselves that heave and tremble,
lashed into fury by perpetual tempests ; roaring geysers,
that ever and anon throw up intermittent jets of boil-
ing water and steam from these tremulous lands. In
the dim horizon the red gleam of fire shoots forth from
yawning chasms, and fragments of molten rock with
clouds of ashes are borne aloft; incessant flashes of light-
ning evoked by the vast chemical changes which are
taking place, dart to and fro, shedding a lurid glare
upon the seething ocean-cauldron beneath ; while bursts
of echoing thunder, peal on peal, complete the grand but
awful picture.

Geology (ge the earth, and logos a discourse) may be
defined as the history of the earth's crust as taught by its
rocks and fossils.

INTRODUCTION. 21

2 he JZarth's Crust. — This is evidently thickening
from age to age as the cooling process goes on. Our
examination of it is very superficial, extending down-
ward not more than ten miles. On a terrestrial globe,
eighteen inches in diameter, the deepest wells, mines,
and valleys would be exaggerated by a delicate scratch
upon the varnish with a pin. It is generally believed,
however, that the solid shell is not over fiffrjr miles in x
thickness, and that the interior is still a molten mass.
The facts upon which this opinion rests are as follows :

(1.) THE TEMPERATURE INCREASES AS WE DESCEND.
—The rate varies in different localities, but is always
over 1° F. for every hundred feet. At fifty miles this
would give a temperature of at least 3000° F., sufficient
to melt the most refractory rocks.* At a depth of fifty
or sixty feet, there is a uniform temperature, unaffected
by the vicissitudes of the seasons ; and in deep mines the
heat becomes almost unendurable.

(2.) ARTESIAN WELLS FURNISH WARM WATER. — The
hospital at Grenelle is heated by water from an Artesian

* It should here be noticed that the current of geologic thought now sets
toward the view that the interior of the earth is solid. Among other objections
urged against its being a fluid, as has been heretofore universally held, are the
following : 1. That the attraction of the sun and the moon upon such a liquid
ocean would raise a tidal wave that would produce regular and sensible undula-
tions of the crust ; and that to make the earth as inflexible as it is, would require
it to be solid halfway to the centre. 2. That, as pressure elevates the melting-
point of a substance, the immense weight of the earth's crust would keep the
interior solid, even at the high temperature supposed there to exist. By those
holding this view, the word "• crust " is used to indicate the rocks of the earth as
far dowr? as they have been examined. Volcanoes are accounted for on this
theory by supposing that there are isolated caverns full of molten matter, or that
the rocks are locally melted here and there by the enormous friction caused by
their shifting and rubbing together during the contraction of the surface in its
constant cooling. The expulsion of the liquid mass is thought to be due to the
explosive violence of steam produced when water by any chance percolates down
to the heated mass.— The average specific gravity of rocks is 2.5, while that ol ^
the earth is about 6£. Hence it may be that the core consists of metals, as iron,
which would account for the earth's magnetism. (See Physics, p. 190.)

2 GEOLOGY.

well 1800 feet deep. In Wurtemburg, large manufac-
tories are warmed in the same manner, the water being
conducted through the buildings in metallic pipes. In
the Garden of Plants, in Paris, the pipes are laid in the
soil ; and at Erfurt, Saxony, a salad garden is thus made
to yield its proprietor an income of $60,000 per annum.
The well at Louisville, Ky., furnishes water of a steady
temperature of 76^°, and the one at Charleston, 1250
feet deep, water of 87°.

(3.) HOT SPRINGS AND GEYSERS.— One of the former
in Arkansas has a temperature of 180°. The geysers of
Iceland and California are fountains of boiling water,
The great geyser throws a column of mingled steam and
water, eight yards in diameter, to a height of 200 feet»
Near the Sahwatch River, Col., is an immense spring so
hot that the hunters sometimes cook their provisions
in it.

(4.) ELEVATIONS AND DEPRESSIONS OF THE EARTH'S
CRUST. — The land in various places has been uplifted or
depressed, either by convulsive throes or by a slow move-
ment continued through centuries. This indicates that
the ground on which we tread has not an unyielding
support. (See note, p. 253.)

(5.) VOLCANOES. — These throw up great masses of lava,
which is merely molten rock. There are several hundred
volcanoes which are known to be either constantly or oc-
casionally active. The amount of melted matter they eject
is enormous. Two streams of lava flowed from Skaptar
Jokul, a crater in Iceland, in 1783 — one fifty miles long
and twelve broad, the other forty miles long and seven
broad; each was one hundred feet deep. When we think
of such fiery torrents, and that the lava everywhere is

INTRODUCTION. %8

essentially the same in its composition, we can but con-
sider the interior of the earth as a melted mass, and the
volcanoes as the chimneys of this huge central furnace.

(6.) EARTHQUAKES. — Within the past fifty years, over
2,000 earthquake shocks have been recorded. They are
accompanied by volcanic eruptions, jets of boiling water,
and heated gases. The only rational explanation is that
they are produced by tidal waves or some terrific convul-
sion in the fiery ocean beneath.

Methods of Geological Study. — UNIFORMITY or
NATURE. — The earth is a microcosm — the universe in
miniature. The laws which govern our world govern
all worlds. The elements of matter of which it is com-
posed are the same as those which make up the farthest
star in space. The earth, therefore, as Prof. Dana beau-
tifully says, though but an atom in immensity, is immen-
sity itself in its revelations of truth ; and science, though
gathered from our small sphere, is the deciphered science
of all spheres. As this world thus reveals to us the
laws of other worlds, so the present time makes known
to us the laws of past time. The geologist believes
in the unchangeableness of God's laws. All results are
brought about by established methods. The same effects
are always produced by the same causes. The motions
of the heavenly bodies, the principles of heat, electricity,
chemical affinity, etc., are the same now as they have
been from the beginning. The geologist sees God work-
ing in nature through the uncounted ages of the past as
He works to-day, not fitfully, but uniformly developing
the mighty plan of the universe. Thus a knowledge of
the present is the magic key whereby the geologist un-

84 GEOLOGY.

locks the history of the past. Let us notice a few of the
practical applications of this principle.

Sedimentary ffioc&s. — The rain which falls on
the hills runs down every slope, washing the soil into
the brooks and rivers, thence to the lake or sea. It is
there deposited as a soft mud or sediment in horizon-
tal layers or strata (singular, stratum). The process is
necessarily slow, but uninterrupted. Year after year,
century after century, adds layer on layer, the more
recent deposits concealing the more ancient. If we

FIG. 2.

Ripple Marks.

visit the sea-shore, we shall see the fine sand washed up
by the waves, and spread, layer upon layer, in a similar
manner, each wave rippling its tiny ridges, and covering
others beneath its shifting sands. The geologist exam-
ines the solid rocks, and finds strata composed of fine
sediment arranged in layers, with oftentimes ripple marks
curving the surface, appearing as distinct as if the tide
had just ebbed. He finds rocks presenting the look of

INTRODUCTION. • 25

half-dried mud from which the water had been evapo-
rated but yesterday, leaving cracks and even prints of

rain-drops so clearly defined that one can tell from what
j~ j

direction the storm came which fell on those mud flats
of the olden time. (See Fig. 3.) He notices other strata

FIG. 3.

a. Modern impressions of rain-drops.

b. Carboniferous impressions of rain-drops.

composed of sand, gravel, or round water-worn pebbles,
such as are now seen along the shore of river or lake
among swiftly moving waters. Again, he discovers banks
of sand or clay where the process of rock-making is still
progressing, and the material is in all stages of harden-
ing. He therefore decides that all similar stratified rocks
have been formed by the action of water, and hence calls
them sedimentary.

TEACHINGS OF THE SEDIMENTARY EOCKS. — The water
records the history of the land. Not only is the inani-
mate dust of earth carried into the vast storehouse of
the sea, but there lie millions of shells of every shape

26 9 GEOLOGY.

and hue ; there, into the soft, oozy bottom settle the
remains of countless fishes which have thronged the
waters ; thither float leaves and reeds, and trees torn
up by the tempest, swept seaward from every shore ;
there sink skeletons of sea-fowls, exhausted land-birds,
and animals borne to the sea by rapid rivers ; ships with
their unclaimed cargoes, gone on their final voyage and
in harbor at last ; drowned mariners lying in their quiet
graves unconscious of the fiercest storm that sweeps
above them — all these varied relics are slowly buried by
the ever-settling sediment. The bottom of the ocean is
a cemetery in which lie the dead from the three king-
doms of Nature. Layer by layer are gathered the re-
mains of each passing year, the history of every age
being thus deposited and built into the very founda-
tions of the earth. Could we gain access to this sea-
bottom, we should find revealed, with each layer turned
up by our spade, a fresh page of the history of the world.
The ocean is now making up a continuation of this his-
tory. The geologist is reading the earlier volumes in the
stratified rocks, the sea-bottom of the olden time.

ffioc&s. — The geologist watches the action
of volcanoes and earthquakes at the present day. He
notices that rocks of various consistency and character
are formed from the cooling lava, and that stratified or
sedimentary rocks are displaced and rent, the fissures
being filled with injected matter. In the earth's crust,
at various places, the exact counterparts of these rocks
and these displacements occur. The rocks are not ar-
ranged in layers, but piled up in mountain masses, break-
ing through the stratified rocks, tilting and throwing

INTRODUCTION. #7

them out of their original positions. The observer has
no more difficulty in accepting the evidence that the
unstratified rocks give of former igneous action and con-
vulsion than in admitting the eruptions and earthquakes
of Etna and Vesuvius.

TEACHINGS OF THE IGNEOUS KOCKS.— The geologist
calls all rocks which indicate the action of fire igneous,
and ascribes dislocations of strata and filling up of cracks
with igneous products to the operation of ancient vol-
canoes and earthquakes. If he is not correct in his con-
clusions, then Nature is not uniform, and is making the
same kind of rock on one day. by fire and on another by
water, and thus all the history of the past is a delusion.

Fossils (fossilis, dug up) is a name applied to all
animal or vegetable remains which are found embedded
in the rocks of the earth's crust. What we have already
said concerning the sedimentary rocks shows us how
fossils are now forming and have been formed in all
time.* As the autumnal leaf drops into the stream, and

* These remains were known to the ancients, and considered "freaks of Na-
ture." Tradition, which attributed to Achilles and other heroes of the Trojan
war a height of twenty feet, is traceable, no doubt, to the discovery of ele-
phants' bones near their tombs. Thus, for example, we are assured that, in
the time of Pericles, in the tomb of Ajax was found a knee-bone of that hero
which was as la"rge as a dinner plate. It was, probably, the fossil knee-bone
of an elephant. The Spartans prostrated themselves before the remains of
one of these animals, in which they thought they recognized the skeleton of
Orestes. Some bones of a mammoth found in Sicily were considered as
having belonged to Polyphemus. Even the learned of a later day were not
exempt from these blunders. Felix Plater, Professor of Anatomy at Basle, in
1517, referred the bones of an elephant discovered at the roots of a tree torn up
by the wind near Lucerne, to a giant at least nineteen feet high. He even
restored it in a skdleh which was long preserved in the college at Lucerne.
In England, similar bones were regarded as those of the fallen angels 1 When
geology first began to be studied, people generally considered the deposition of
fossils as having a connection with_Noah^-flo°4' Cuvier found the skeleton

a E o L o G r.

becomes imbedded in its mud— as the trees of the forest
are borne down by the flooded river and are ultimately
entangled in the sediment of its estuary— as the coral
reef and shell-bed are gradually increasing and growing
steadily into limestone before our eyes — as the skele-
tons of animals are drifted by the tide and fall to the
sea-bottom or sink into rivers and marshes, and are thus
preserved from rapid decay — so in all time past have
similar agencies been at work ; here preserving the bro-
ken twig and the fallen forest, there the coral reef and
the shell-bed, and anon the remains of animals that were
borne by rivers from the land, or drifted by the waves on
the muddy sea-shore.

TEACHINGS OF THE FOSSILS. — Digging in the soil, we
find a bone. We examine it. It is one of the vertebrae
of a horse. We believe it to be real. It is not a "freak
of Nature," but was once part of a living horse. We dis-
cover some strange fossil bone, and are led irresistibly to
a similar conclusion. The skilful anatomist, understand-
ing perfectly the relation that exists between the different
parts of the animal frame, whereby each portion subserves
its part toward the development of life and its functions,
can restore the entire form, and even indicate the habits
of the creatures that formerly peopled our globe. For
example, a sharp claw belongs to a flesh-eating animal
with sharp cutting molars ; a hoof, to a grazing species

of a gigantic salamander preserved as a specimen of the accursed race swal-
lowed up by the deluge.

When we speak of fossils being converted to stone, we do not mean that the
particles of the original substance have been changed to stone, but that, as they
decayed, they have been replaced by stone. This is true, however, only of the
fossils of the older formations. The new ones retain their original substance.
Shells of the Tertiary Period can often scarcely be distinguished from modern
onea, while sharks' teeth exhibit their enamel intact.

INTRODUCTION. 29

with broad molars. Knowing, too, the conditions neces-
sary to the life of such animals, he can also decide upon
the climate, food, etc., which then existed. Agassiz, from
a single scale, reconstructed an entire fish. Subsequent
discoveries proved his idea to be singularly accurate. The
restoration of the megalosaur by Hawkins is a remarkable
instance of a similar character. (See Fig. 83.) A /££

We visit the sea-shore, and gather shells along the
beach. On digging, we discover others buried from
sight. These are filled with damp sand, which perfectly
retains their impress. In the quarry among the layers
of sedimentary rocks, we find similar fossil shells. They
are certainly the remains of ancient life, and must have
existed when the rock was in process of formation. They
prove the rock to have once been under water. If the
shells are marine, it was the sea ; if fresh water, a lake or
river ; if intermediate, an estuary. The testimony is as
conclusive as if we had lived by that ancient shore, and
had witnessed their growth, decay, and entombment in
the sand.

In certain clay beds of England, shells are found of
species now existing only in polar seas. We thence infer
that when that clay was deposited, and those shells were
inhabited, a climate similar to that of Greenland must
have prevailed in British latitudes. Eemains of the rein-
deer and musk ox occur in France. These indicate a
former Arctic temperature, unless we are to suppose that
the habits of those animals have entirely changed since
the time of their existence in southern Europe.

Action of Glaciers (Gla'-seers). — Philosophers
have carefully studied the effects of moving masses of

80 GEOLOGY.

ice. They have seen how the glacier pushes its way
down the Alpine valley, grinding, rounding, smoothing,
and marking the rocks over which it passes, and de-
positing at the bottom its burden of debris. They have
watched the glaciers of polar regions collecting on the
sea-shore until at last great mountains of ice break
loose and float southward. They have seen these ice-
bergs grounding and melting in a more genial clime,
where they finally drop their load of rocky fragments on
the sea-bottom.

TEACHINGS OF THE GLACIERS. — The geologist, in re-
gions now far removed from glacial action, finds the
lower extremities of mountain glens and valleys heaped
with mounds of sand and gravel, and the rocky surface
marked with parallel grooves, such as no known agency
except the glacier ever produces. Resting on the lower
hills and scattered over valley and plain beyond, he sees
great bowlders of a weight far exceeding the transporting
power of water, miles removed from their parent rocks,
and with their sides smoothed and marked. He ascribes
these results to glaciers and icebergs. He assumes that
these mountains were once covered with snow, these
glens once filled with glaciers, and that these lower
lands were the bottoms of seas on which floating ice-
bergs grounded, and, melting, left their loads of rocky
debris.

Chronology. — Many geological facts aid in deter-
mining the relation of different events in respect to time.
The following instances illustrate the method :

CAVES. — In certain caves the bones of various ani-
mals are found embedded in a calcareous deposit, which

INTRODUCTION. SI

has accumulated on the floor by water slowly dripping
from the roof. Many of the bones have been gnawed, and
the hollow ones split lengthwise. The geologist considers
the former the work of den-frequenting, carnivorous
animals, and the latter of a marrow-sucking race of
men. This conclusion is still further substantiated by
finding traces of the hyena, and also stone-hatchets,
ashes, and charred sticks of wood. Man, only, lights a
fire. Hence we are as sure of the existence of a rude
cave-dwelling tribe of men as if we had witnessed their
grim countenances lighted up by the fires of which
those fragments were the latest embers. The hyena and
the cave-dwellers lived at the same epoch. The deeper
the layer the older the remains. If we can only deter-
mine the rate at which the soil accumulates, we can
estimate with some degree of accuracy their antiquity.

LAKE-BOTTOMS. — We drain a level, basin-shaped mead-
ow. The general form and location suggest the idea
that it may anciently have been the site of a lake.
The moment, however, we dig below the surface, the
geologic evidence converts the inference into a matter
of certainty. We pass through first the soil, next a layer
of peat, then one of marl, and lastly, one of clayey sedi-
ment. In the peat we find antlers of deer and bones of
oxen ; in the marl, fresh- water shells ; and in the sedi-
ment, a log hollowed out into a rude canoe. Here we
have the whole history of the lake, and in reading it we
can trace the successive stages as clearly as if we had
lived by its shores from the time it was a sheet of shal-
low water to the hour of its final obliteration. First,
the open lake, over which the simple native paddled his
rude canoe ; second, the shallower sheet, where fresh-

S2 GEOLOGY.

water shell-fish luxuriated in myriads, and succeeded
each other, generation after generation ; third, the peat
marsh, over which deer and oxen occasionally ventured,
and were mired ; and fourth, the level meadow, when
the site became too dry for the peat-forming plants to
flourish. We have no exact chronology for these events,
and can decide only their order. The canoe may have
sunk one thousand or five thousand years ago, for aught
we know. If, however, we can form some idea of the
rate at which the sediment was deposited, or the marl
and the peat formed, we can then judge somewhat of its
antiquity.

SCOTTISH ILLUSTRATIONS. — Such ancient lake-bottoms
are seen in the Lowlands of Scotland. The geologist
finds below the peat-bog the bones of horse, pig, deer,
dog, and man ; deeper still, the Roman eagle or sword ;
next, the bones of the wild ox, bear, wolf, beaver ; then
the wooden canoe ; below the marl, bones and antlers of
the gigantic Irish elk, and tusks of the great mammoth ;
and at the bottom the solid rock, strewn with ice-borne
blocks, the original bed of the lake when its waters were
first gathered together. Occasionally, also, raised mounds
of piles, plank, branches, stones, and other material are
laid bare. These were the foundations of the lake-dwell-
ings of former days, raised by primitive men for their
defence. They reveal stone hammers, flint spear-heads,
split bones, and fragments of rude pottery-ware. What
a marvelous history we read from these records of Na-
ture ! In the beginning there is the clear sheet of
water rippling in the European landscape — for Great
Britain has not yet been separated from the continent
— surrounded by forests of pine, birch, and willow. The

INTRODUCTION. 33

climate is severe, and the woolly-haired mammoth
tramps through the overhanging bushes down to the
water's edge. Centuries pass. Reindeer and Irish elk
betake themselves to the water in summer, and sink into
its miry depths, or seek to cross its frozen crust during
the winter's snow, and are buried beneath the treacher-
ous surface. Ages roll on. The climate becomes milder,
and Britain is detached from the continent. The lake
is gradually becoming shallow ; reeds and bulrushes en-
croach upon its margin ; oak clumps- adorn its banks,
along which prowl the wolf and bear ; the beaver builds
his dam across the entering stream, and the wild ox and
red deer stand lolling in its cool waters. A race of short,
broad, round-headed men settle by the shore, pile the
mounds and wattle their simple lake-dwellings ; with fire
and stone adzes scoop out the oak-trunks into canoes,
spear the ox and deer in the woods, and enjoy the com-
forts of a dawning civilization. Time passes. Still the
lake grows shallower, and its reedy margin broader. A
new race of men — taller, higher-headed, and more nimble
— take possession of the scene. They settle the slopes,
erect their rude altars in the oak clumps, domesticate the
ox, horse, and dog, and attempt a scanty cultivation of
the soil. The Roman legions at last — we know the date
of that event, about two thousand years ago — invade the
country, scatter the natives, and encamp by the lake.
They erect their votive altars, make plank roads through
the marshy borders, and drop their implements and uten-
sils by the side of those of the ancient Briton. The pre-
historic ages have now passed, and we can more easily,
but still somewhat confusedly, continue the onward his-
tory of the fast lessening waters. The Romans dis-

OE OL 0 G T.

FIG. 30.

appear. Celt and Saxon contend for the soil, and we
trace in the uppermost bog-earths the remains of existing
breeds of oxen, sheep, horses, pigs, dogs, and other animals,
and even implements of iron belonging to successive
stages of civilization down to the present time. — (Page^)

Italian Illustration. — Near the town of Pozzuoli,
Italy, are the remains of the ancient temple of Serapis.

Three marble pillars,
forty-two feet high,
are especially notice-
able. They stand
on a pavement now
three feet under wa-
ter. Six feet be-
neath is another
pavement. For a
height of twelve
feet the surface of
the pillars is smooth ;
but above that a zone
of nine feet in width
is perforated with
holes, at the bottom

Temple of Serapis, Pozzuoli. of each Qf which lies

the shell of a little boring bivalve still found in the neigh-
boring waters. These facts show that the ancient pave-
ment must have settled six feet, when the second one was
constructed. Later, it subsided twenty-one feet beneath
the water, giving the borers an opportunity to penetrate
the stone. Next, the pavement rose, lifting the bivalves
out of the water. Previous to 1845 the foundation was
again slowly sinkino-. but since has been steadily rising.

(A Stone=(Discourse)

o4.nct this our life, exempt from public haunt.
Finds tongues in trees, books in the running brook»9
<S«rmons in stones, and good in everything."

SHAKESPEARE.

Geology (lithos, a stone, and logos, a
discourse,) means, literally, a discourse about stones.* It
treats of (1) the Composition, (2) the Classifica-
tion, and (3) the Structure of the rocks which make
up the earth's crust. Underneath the soil and the sea
there is everywhere a rocky foundation which protects
us from the fiery interior. Along the sea-shore, river-
side, road-cuttings, etc., this solid basement is exposed
to view. It is generally arranged in layers, sometimes
loosely, as sand, clay, or gravel, and sometimes partly
hardened into stone. Since it passes thus insensibly

* TherJ is no natural object out of which more can be learned than out of
stones. They seem to have been created especially to reward a patient ob-
server. Nearly all other objects in Nature can be seen, to some extent, with-
out patience, and are pleasant even in being half seen. Trees, clouds, and
rivers are enjoyable even by the careless. But the stone under the foot has
nothing for carelessness but stumbling ; no pleasure is to be had out of it, nor
food, nor good of any kind ; nothing but symbolism of the hard heart and
the unfatherly gift. Yet do but give it some reverence and watchfulness, and
there is bread of thought in it more than in any other lowly feature of all the
landscape. For a stone, when it is examined, will be found a mountain in
miniature. The fineness of Nature's work is so great that into a single block,
a foot or two in diameter, she can compress as many changes of form and struc-
ture, on a small scale, as she needs for her mountains on a large one; and
taking moss for forests, and grains of crystal for crags, the surface of a stone,
in most cases, is more interesting than the surface of a hill ; more fantastic in
form and inconceivably richer in color.— Ruskin.

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40 LI THO LOGICAL GEOLOGY.

from one stage of consolidation into another, the geolo-
gist applies the term rock alike to all. The desert of
Sahara is a sand-rock. Ice is a rock as certainly as is
limestone.

COMPOSITION OF THE MOCKS.

Rocks are composed, in general, of three common sub-
stances— Quartz, Clay, and Z/imeslone. Wherever
you stand on the solid ground, in any country of the
globe, you may be sure that the rock under you is mainly
some form or compound of one or more of these earth-
builders.*

(i.) SILICA

/. Quartz (silica, silex) is the oxide of silicon, a
rare non-metallic substance known only to the chemist.
Silica is the most abundant of all the minerals, compris-
ing one-half of the earth's crust. It is so hard that it
strikes fire with steel, scratches glass like a diamond, and

* Since there were so few substances, Nature seems to have set herself
about making these three as interesting and beautiful as she can. The clay,
being a soft and changeable substance, she doesn't take much pains about— she
only brings the color into it when it takes on a permanent form on being baked
into brick. (Raskin's statement does not hold good in America. For examples,
the clays of Southern Virginia and North Carolina are beautifully mottled, the
cliffs at Gay Head present brilliant tints, and the porcelain clays of Western
Kentucky exhibit fine coloring.) But the limestone and flint she paints in her
own way, in their native state ; and her object in painting them seems to be
much the same as in her painting of flowers— to draw us, careless and idle
human creatures, to watch her a little, and see what she is about, that being, on
the whole, good for us, her children. To lead us to do this she makes picture-
books for us of limestone and flint ; and tempts us, like foolish children, as we
are, to read her books by the pretty colors in them. The pretty colors in her
limestone books form those variegated marbles which all mankind have taken
pains to polish and build with from the beginning of time ; and the pretty

COMPOSITION Of THE HOCKS. J^l

cannot be cut with a knife. It has no cleavage,* and
breaks into irregular fragments having a glassy lustre.
It is insoluble in any acid (except hydrofluoric), and
melts only in the heat of the compound blow-pipe. On

FIG. 4.

A Cluster of Quartz Crystals from Lake Superior.

colors in her flint books form agates, jaspers, carnelians, etc., which men
have, in like manner, taken delight to cut and polish and make ornaments of
from the beginning of time ; and yet so much of babies are they, and so fond of
looking at the pictures instead of reading the books, that I question whether,
after six thousand years of cutting and polishing, there are more than two or
three out of any hundred who know, or care to know, how a bit of agate or
marble was made or painted.— Ruskin.

* Cleavage is the property of splitting with smooth surfaces in certain fixed
directions. Many crystals separate very easily in those joinings which Nature
has made.

J$ L1THOLOG 1 CAL GEOLOGY.

account of its hardness, which resists the action of the
elements, it comprises a large part of ordinary pebbles,
sand, and much even of the soil. It is found in crys-
tals of the form shown in the figure. When pure, like
those of other minerals, they are generally small, and
sometimes occur in beautiful clusters. Crystals of great
size, though of inferior clearness, are occasionally seen.
Dartmouth College cabinet possesses a group weighing
147 pounds. At Milan is a single crystal 3J feet long and
5J feet in circumference, estimated to weigh 870 pounds.

2. Itock Crystal is the clear crystalline quartz.
The name is derived from the Greek word krustallos,
meaning ice. The purest specimens are often cut for
jewelry, and sold as " white stone " and " California
diamonds." They are also used for spectacle glasses.
Anciently they were cut into vases and cups, some of
which are still preserved as curiosities. It is said that
Nero, on learning of the insurrection which led to his
fall, dashed into pieces two crystal vases, one valued at
$3000. Pure quartz sand is used in large quantities for
making glass.

Quartz, when colored by the various metallic oxides,
presents a bewildering variety. The young geologist,
after having gathered a very respectable collection of
minerals, has often been surprised to learn that he has
hardly passed outside of this legion family.

3 '. 3tose or *Pinfc Quartz is rarely found as crys-
tals, but generally as a massive rock. On exposure to
the light, the color sometimes fades, but it can be re-
stored by leaving the stone for a time in a damp place.

COMPOSITION OF THE ROCKS. 43

SMOKY QUARTZ has a dark-brown, smoky tint. It is
often black and opaque, except in thin portions, which
are semi-transparent.

MILKY QUARTZ is a milk-white, opaque, massive
variety, looking not unlike porcelain.

GRANULAR QUARTZ consists of small grains of quartz
cemented into a massive rock. It has a texture similar
to that of loaf-sugar, and oftentimes crumbles easily into
sand. It is used for hearthstones, furnaces, etc., and,
when powdered, for making sand-paper, glass, or pottery.

& . jlmet/iyst has a beautiful purplish tint from the
oxide of manganese, which it contains. The name means
" a preservative from intoxication," and was given it from
a belief of the ancient Persians, that wine drunk from an
amethyst cup lost its inebriating properties.

5 '. Chalcedony is distinguished by its waxy, horn-
like lustre. It has generally a white or brownish shade.
When bright red, it is a carnelian. When brownish red,
a sard. When colored apple-green with nickel, a chrys-
oprase.

6 '. Agate is a kind of chalcedony, in which the dif-
ferent shades of color are arranged in parallel lines — the
edges of the layers which compose the stone. These
layers are very like the coats of an onion, and represent
the successive deposits by which the agate was formed.
They are often so thin as to number fifty within an inch.
When the lines are zigzag, it is termed a fortification
agate, from the resemblance to the irregular outlines of a
fortress. When the stripes alternate, an opaque with a

44 LITHOLOGICAL GEOLOGY.

transparent band, the stone is termed an onyx (onyx, a
nail), from a fancied resemblance to the alternating lines
on the finger-nail. When a deep brownish-red stripe (a
sard) alternates with a white one, the agate is called a
sardonyx. When a yellowish-brown oxide of iron is dis-
seminated through the stone in moss-like forms, it is
termed a moss agate.

Keal cameos are cut from the onyx. The most cele-
brated of the ancient cameos is the Mantuan vase at
Brunswick. It was cut from a single stone. It is in the
form of a cream-pot, about 7 inches high and 24- broad.
On its outside, which is of a brown color, there are white
and yellow groups of raised figures, representing Ceres
and Triptolemus in search of Proserpine. The lines of
agates sometimes present a striking resemblance to vari-
ous objects. Some are so remarkable as to be, without
doubt, exceedingly ingenious works of art. Thus, Pliny
tells of an agate, belonging to Pyrrhus, in which were
pictured the nine muses, and Apollo in the midst playing
on his lyre. Agates are very abundant on the shores of
Lake Superior, and many Likes and rivers of the west.
Externally the agate is rough, and exhibits no sign of
the beautifully varied appearance it will present when
polished.*

* AGATE MANUFACTURE. — The most celebrated agate quarries are at Ober-
stein, Germany. The nodules are of an ashen-gray color. After being washed,
they are placed in a vessel containing honey and water, which, being closely
covered, is kept in hot ashes for two or three weeks. The stones are then taken
out, cleansed, immersed in sulphuric acid, and then roasted a second time in
the hot ashes. The honey, penetrating the pores, is carbonized either by the
long-continued heat or the action of the acid. The depth of the color depends
on the porosity of the agate. Some become perfectly black, others take a rich
brown or chocolate tint, some are striped alternately like the onyx, while
ethers resist all attempts to change the natural hue. By soaking the porous
agates in a solution of sulphate of iron, and then heating in an oven, a fine

COMPOSITION OF THE ROCKS Jfi

7. Jasper is a dull, massive variety of quartz, with
a little clay. It has shades of red, yellow, brown, and
green, owing to the presence of iron in different stages
of oxidation. The yellow becomes red by heat, which
changes the yellow oxide of iron to red. When the colors
are arranged in stripes, it is termed rMon jasper. It is
susceptible of high polish, and is therefore much prized
for ornamental purposes. When of a deep green, with
dark red spots, it is named Hood-stone. At Paris there
is a bust of Christ carved from this stone in such a
manner that the red spots represent the drops of blood.
A hard, velvet-black jasper is called the touchstone. It is
used for testing the purity of gold alloys. This is done
by rubbing the alloy on the stone, and comparing the
color with that of some known alloy. The stone is
adapted for this purpose because of its hardness and
smoothness, and also because it presents a good back-
ground on which to compare colors.

8. Opal is a very beautiful variety of quartz. It
contains ten per cent, of water, which is combined with
the silica. It is softer than quartz, and, unlike it, is
easily soluble in a hot solution of potash. Its external
color is a pure white, but when broken it exhibits a play
of rich and delicate internal reflection. A kind called

carnelian red is produced. A blue color, which has all the effect of a turquoise,
is also developed by a process not yet divulged. By roasting, the natural colors
are heightened and rendered more permanent. In these various ways a coarse
and valueless stone may be so changed as to pass for a gem of the first quality
The agates are ground on rough stones, turned by water-power from the numer-
ous little brooks which abound in that neighborhood, and polished on soft
wooden wheels with powder of tripoli (see page 48) found near by. Vases, cups,
seals, knife-blades, agate mortars for the chemist's use, etc., are made in such
abundance as to become articles of commerce.

46 LITHOLOGICAL GEOLOGY.

liydrophane is remarkable for becoming transparent when
dipped into water.*

9. Sandy 'Pebbles, Gravel, Cobblestones, etc.,

consist largely of quartz, since it resists the action of the
water longer than other rock materials. The color is
due to the various oxides of iron ; f although it is some-
times a mere stain produced by vegetable matter.

70 . .Flint is a compact form of quartz of various
colors — white, brown, and even black. It breaks into
fragments having a sharp edge and a conchoidal J sur-
face. Its use formerly for gun-flints and by the Indians
for arrow-heads is well known.

HORKSTONE is an impure variety of flint, so named
from its color and appearance. Buhrstone is a kind of
flint possessing a cellular texture, which makes its sur-
face very rough. In many of the best stones the cavities
equal the solid portions. It is found in various States

* The same phenomenon is shown in an ox's eyeball. When plunged into
water, it vanishes instantly from the sight. Both refract light at the same angle
as water, and hence the eye has no power of distinguishing them.

t Iron is Nature's universal dye. Without it the soil would be a dirty white—
the color of snow in a time of thaw. Instead of the pretty lively color of sand
and pebbles, we should see the dull and somber hue of ashes ; and instead of the
glittering sand of the sea and lake shore, a plain drab or gray, which no wealth
of sunshine or of spray could turn to beauty. The slates used for roofing have
a warm rich tint ; oxide of iron puts vermillion into them as it does into our
bricks, which else would be only a plain pepper and salt. The ruddy hues of
brown now seen in ploughing sandy fields, contrasting so richly with the green
of woods and meadow, would be, without the iron, only the cold repulsive gray
of clayey soils. Many marbles, too, are colored with this same familiar dye.
" The violet veinings and variegations of the marbles of Sicily and Spain, the
glowing orange and amber of Sienna, the blood-red color of precious jasper
that enriches the temples of Italy,11 are all painted with iron-rust. Thus by an
infinity of design does God, from the simplest, commonest material, interweav-
ing the beautiful in Nature everywhere, cultivate our taste and adorn the world
for our happiness.

f A conchoidal surface is one that is curved like the inside ol a watch-crystal.

COMPOSITION OF THE ROCKS.

are minute one-

FIG. 5.

— Ohio, Massachusetts, Arkansas, Georgia, etc. The
buhrstone of Ohio contains some lime, and it has been
thought that the cellular character may be due to the
partial dissolving of the lime out of the stone.

ORIGIN OF QUARTZ. — Though quartz is a mineral,
probably most of the flint and hornstone which we find
is of animal or vegetable origin. Sponges secrete little
spicules or points of silica.
celled vegetable organisms,
too small to be seen singly
by the naked eye. Yet when
gathered in countless myri-
ads, they appear as a brown or
reddish slime.* They have
the power of separating the
silex from the water in some
unknown way. These plants
grow in such numbers that
after their death their inde-
structible siliceous coverings
so accumulate as to form
strata of great thickness and

Diatoms Irom Albany and WaterfordL

extent. The hardness, sharp- Maine>

ness, minute size and fragil-
ity of the particles, whereby

B is magnified 25 Diameters.
C is magnified 250 Diameters.
D is magnified 200 Diameters.

* Dr. Hooker, in his account of the Antarctic regions, says : " Everywhere the
waters and the ice abounded in these microscopic vegetables. They stained the
iceberg and pack-ice wherever the latter was washed into the sea, and imparted
to it a pale ocherous color. In the 80th deg. of S. latitude, all the surface ice
carried along by currents, and the sides of every berg, and the base of the great
Victoria barrier itself — a perpendicular wall of ice from one to two hundred feet
above the sea level — were tinged brown from this cause, as if the waters were
charged with oxide of iron." It is a curious fact that these minute, flint-secret-
ing diatoms are the food of the soft, almost impalpable, jelly fish, and, as has
been lately stated, that this in turn constitutes the food of the huge whale.

48 LITHOLOGICAL GEOLOGY.

they fall to pieces at the least touch, make the mass
useful as a polishing material. Tripoli, or polishing
slate, is composed of these siliceous remains, a single
cubic inch containing 41,000,000, so that at every stroke
made with the powder millions of perfect fossils are
crushed to atoms. The mountain meal, or fossil farina
of Tuscany, is a mass of these organisms. In Lapland a
similar earth is found, winch in times of scarcity the
inhabitants mix with the ground bark of trees, and use
for food. This infusorial earth, as it is termed, is
found at various localities in this country, as at Rich-
mond, Va., Maidstone, Vt., Waterford, Me., etc. At
Bilin, Bohemia, besides a stratum of tripoli 14 feet
thick, a kind of semr-opal occurs, composed of diatoms
and sponge spicules, cemented with siliceous matter. It
is thought that the more delicate shells were dissolved
by the water, and thus formed opal cement, in which
the more durable of the fossils are preserved, like insects
in amber. Flint and hornstone, under the microscope,
reveal the outlines of spicules of sponges, of diatoms,
and of other animalcules. We are thence led to believe
that perhaps the larger part of the quartz we find, in
all its Protean forms, has impressed upon it an organic
structure which it received at an inconceivably remote
time, when it was animated by microscopic life.

(a.) ALUMINA.

Alumina is the oxide of the metal aluminum, which,
on account of its abundance in clay, is called the
" clay metal." In hardness, alumina is inferior only
to the diamond, and will easily scratch quartz. Pure

COMPOSITION OF THE ROCKS.

crystallized alumina, when red, constitutes the ruby.
This ranks in value next to the diamond, and some per-
fect specimens have sold at even a higher rate. The
dull-colored variety is called corundum, and the coarse
granular kind, combined with magnetic iron ore, emery.
(See feldspar and common clay, page 53.)

(3.) LIME.

/. Carbonate of Zdme is more commonly called
" limestone.'5

(a.) LIMESTONE is a compound of lime and carbonic
acid. It embraces all shades from white and cream color
to a dense black. . It may be known by its softness —
being easily scratched with a knife — and by its effer-
vescing with an acid. Limestone is useful for building
purposes, and when the carbonic acid is expelled by beat,
quick-lime is produced.

(b.) CALC-SPAR (Calcite).— Pure crystals of limestone
are called calc-spar. They readily cleave into the rhom-
bohedral form. Trans-
parent crystals are
termed Iceland spar, as
the best are brought
from that country.
They beautifully illus-
trate double refraction.

(c.) CHALK is a por-
ous, unCOmpacted Vari- Object seen through Iceland Spar.

Crystal from Rossie, N. Y.

ety of limestone.

(d.) CALCAREOUS TUFA * is formed by deposition from

FIG. 6.

* Calcareous tufa, or travertine, often forms beds of limestone, which can be

LITHOLOGICAL GEOLOGY.

water charged with carbonate of lime in solution. (Rev.
Chem., page 138.) Stalactites depend from the roof of
caverns in limestone regions. They are produced, like
tufa, from calcareous waters. The water, dripping down
from crevices in the rock, evaporates, deposits its lime-
stone, and thus forms pendants of curious and grotesque
figures. Some hang like icicles, while others look like
falling sheets of water caught in mid-air, and turned
to stone. The drippings upon the floor produce calcare-
ous mounds, called stalagmites. The two, meeting, often
form pillars strangely grouped and interwoven like trees
in a forest, and sometimes even combined into broad
curtains of semi-transparent rock.

*(e.) OOLITE (oon, an egg, and
litlios, a stone) is a limestone
consisting of numerous small,
rounded grains, resembling the
roe of a fish.

(f.) MARL is a mixture of
clay and carbonate of lime.
It is loose, friable, and gen-
erally full of small shells. It
is valuable as a fertilizer.

OOlitic Marble, Chester, England. (g«) MAGNESIAS' LlME-

FIG. 7.

used for architectural purposes. The Coliseum at Kome is built of this rock.
In the vicinity of Rome a solid layer of this stone, a foot in thickness, has been
formed in four months. Springs near the Tiber are famous for their production
of travertine. Indeed, the term travertine means simply Tiber stone. The water
of the river near them is so charged with mineral matter that it is said that
even fish have been entangled and petrified. In certain regions, springs deposit
the tufa so readily that incrustations may be obtained upon sticks, leaves,
baskets, etc. At the baths of San Filipo, Tuscany, the preparation of casts in
this way forms a regular business. Moss petrified in this manner is so plenti-
ful in Caledonia. N. Y., that it is used for building fences. It is also found in
abundance at Chittenango and Sharon Springs.

COMPOSITION OF THE ROCKS. 51

STONE, or dolomite, contains magnesia. It is harder
than limestone, and does not readily effervesce with an
acid unless heat is applied.

(h.) MARBLE is crystallized limestone. When pure,
it is clear and fine-grained, like loaf-sugar. It is of
great value in the arts.* The finest statuary marble
comes from Carrara and the island of Paros, whence
the term, Parian marble, so famous among the Greek
sculptors. The pure whiteness of Parian marble was
thought to be especially pleasing to the gods, hence it
was selected for the work of Praxiteles and other cele-
brated artists. The Venus de Medici, the Oxford mar-
bles, and many noted statues are wrought from this
stone. An excellent building marble is quarried at
Rutland, Vt., in Massachusetts, and in Connecticut.
Marble often contains mica and other impurities, which
give it a clouded and mottled appearance. This de-
tracts from its value, and ruins it for statuary purposes.
Verde Antique is a variety of marble streaked with ser-
pentine.

Marble is sawed into slabs by means of a thin iron
plate, a saw without teeth, driven by machinery. The
friction is produced by sharp sand and water, which are

* What are marbles made for ? Over the greater part of the surface of the
earth we find that a rock has been providentially distributed in a manner
particularly pointing it out as intended for the service of man. It is exactly
of the consistence which is best adapt- d for sculpture and architecture. It is
neither hard nor brittle, nor flaky, nor splintery, but uniform and delicately,
yet not ignobly soft — exactly soft enough to allow the sculptor to work it
without force, and trace on it the finest lines of finished form ; yet it is so hard
as never to betray tbe touch or moulder away beneath the steel ; and so admi-
rably crystallized and of such permanent elements, that no rains dissolve it, no
time changes it, no atmosphere decomposes it ; once shaped, it is shaped for-
ever, unless subjected to actual violence or attrition. This rock, then, is pre-
pared by Nature for the sculptor and architect, as paper is by the manufacturer
for the artist ; nay, with greater care and more perfect adaptation. ~Rmkin.

6% LITHOLOG1CAL GEOLOGY.

constantly applied. The saws penetrate very slowly, not
more than an inch per hour.

ORIGIN OF LIMESTONE. — Limestone forms a promi-
nent constituent of shells, bones, corals, etc. Animals
have the power of secreting the lime from the water in
which they live, or from, the food they eat. When they
die their mineral remains accumulate in great quanti-
ties, and gradually harden into rock. Chalk was formed
by the consolidation of minute shells, smaller than a
grain of sand. As each particle is thus cellular, and
not solid, the chalk has a soft porous structure. The
microscope reveals these tiny shells in the glazing on a
visiting-card. Even when the rock contains no trace
of fossils, it may have been made by the sea breaking
and grinding shells and corals into a fine powder, just as
it grinds rock and pebbles into fine sand. We see this
process now going on in the formation of coral-reefs, as,
for example, off the coast of Florida. From the vast
extent of the limestone rock on the earth, we can form
some estimate of the amount of animal life which has
existed in past ages.

2. Sulphate of Z<ime, or, as it is generally called,
" gyPsum>" 1S a compound of lime and sulphuric acid.

GYPSUM is readily distinguished from limestone by its
inferior hardness. It may be scratched with the finger-
nail, and carved with a knife into any desired shape. It
does not effervesce with the acids.

(a.) UNCRYSTALLINE GYPSUM is commonly known as
"plaster stone." When the stone is crushed and ground
it forms a white powder sold as plaster, and used as a
fertilizer.

COMPOSITION OF VHE HOCKS. 53

(b.) CRYSTALLINE GYPSUM occurs in fibrous masses
with a pearly lustre, known as satin spar ; in scales,
layers, and crystals, pellucid as glass, selenite ; and as a
snowy-white solid, alabaster.

At Grand Rapids, Mich., a mottled variety is found,
which is turned in a lathe into beautiful vases, goblets,
and other ornamental objects. In the mammoth cave,
Kentucky, are found exquisite forms resembling leaves,
flowers, and vines. When burned, gypsum is known as
" plaster of Paris."

(4.) THE SI LICATES.

The Silicates are compounds of silica with other
substances, such as alumina, lime, magnesia, potash,
oxide of iron, etc. The following are the most com-
mon ones :

/. Feldspar. This is somewhat softer than quartz,
and, unlike it, has a cleavage in two directions, each
crystal showing a flat surface and pearly lustre. It has
usually a white or flesh-red color. There are three vari-
eties which are silicates of alumina with an additional
substance, viz : orthoclase or potash-feldspar, albite or
soda-feldspar, and labradorite or lime-feldspar. Albite
(albus, white) may always be distinguished by its marked
whiteness. Labradorite (originally from Labrador) ex-
hibits often a beautiful play of colors from internal
reflection, and is susceptible of polish. Clinkstone, so
named because of the metallic ring it emits when struck
with a hammer, is a compact variety of feldspar.

COMMON" CLAY is formed by the decomposition of feld-

54 LIT SOL 0 G 1 CAL GEOLOGY.

spar rocks mixed with a large proportion of quarlz sand.
Pure feldspar, when decomposed, produces kaolin (from
Kaoling, the name of a locality in China, where it is
obtained), a kind of clay used for making porcelain or
China-ware. The red color of bricks is due to the iron
contained in the clay. Pipe-clay is free from iron. The
beautiful pipe-stone used by the Indians was a compacted
red clay from Coteau des Prairies. A bed of similar clay
is now accumulating in Lake Superior.

2. Mica (micare, to glisten) is commonly called
" isinglass." It is easily known by its lustre and by its
separating readily into thin elastic plates, which may
again be subdivided until many thousand would be re-
quired to make an inch in thickness. It is often seen in
sand as bright, glittering particles. On account of its
transparency it is used in Siberia for windows. It is
employed on board of ships where the concussion would
be liable to break glass, and for windows in stoves.

3 '. Hornblende takes the first part of its name
from its being tough like horn, and the second (blenden,
to deceive) from its sometimes resembling iron-ore. It
has generally a black or greenish -black color and a
pearly lustre. Some varieties present long, slender,
needle-shaped crystals of a delicate green tint and a
glassy lustre. Asbestos (unconsumed) is so fibrous that
it can be spun and woven like cotton. The ancients
made it into napkins, which, when soiled, were cleansed
by being thrown into the fire, where they were burned
clean and white in a few minutes. The Greenlanders
use it for lampwicks, and it formerly served a similar

COMPOSITION Off THtf ROCKS.

Hornblende Crystals in Quartz.
Berkshire, Mass.

purpose in keeping the perpetual fire in the temples,
its incombustibility being thought to render it sacred.
It is said that in Siberia
and Spain, gloves, purses,
etc., are made from ami-
anthus (undefiled), a vari-
ety of asbestos having a
beautiful satin lustre. The
finest locality for asbestos
in this country is at the
Quarantine, New York.

PYROXENE, often called
augite (from auge, lustre),
is a. dark-green mineral, very like hornblende, and some
of its massive specimens can hardly be distinguished
from it. Its crystals, however, are stouter and thicker,
and are never needle-shaped, though it has a fibrous
asbestos which can hardly be distinguished from horn-
blende except by analysis. Augite is a characteristic
constituent of igneous rocks.

^. Talc is so soft that it can be cut with a knife,
and even scratched by the finger-nail. It separates
readily into thin pearly layers, which are not elastic
and tough like those of mica. It has usually a light-
green color, and feels greasy when rubbed with the finger.
A compact variety of talc is familiarly known as "French
chalk."

SOAPSTONE or steatite (stear, fat) is a massive crys-
talline variety which is susceptible of being worked into
any desired form, and of receiving a high polish. It can
be sawed into slabs or turned in a lathe. It is made into

LITHOLOG1CAL GEOLOGY.

inkstands, water-pipes, culinary vessels and fire-stones
for furnaces.

SERPFNTISTE contains about equal parts of magnesia
and silica with 12 per cent, of water. It is not granular
and has generally a dark-green hue and a dull, resinous
lustre. It was named from its mottled colors, resembling
the skin of a serpent. Stoves have been made of it, as it
bears heat well. When polished, " precious serpentine "
has a rich, oil-green tint, and is highly valued for inlaid
work.

CHLORITE is a mineral somewhat resembling talc and
serpentine. It has, however, a dark, olive-green color, a
granular texture, and is much less unctuous to the touch.
It forms a slaty rock very common in some localities.

5. Garnet is a common mineral in connection with

FIG. 9.

Garnets in Mica Schist.

FIG. 10.

Tourmaline Crystals in Quartz.
Alexandria Bay, N. Y.-

mica, hornblende, and gran-
ite. It is found usually in
dark-red crystals of 12 or
24 sides. This dodccahe-
dral form, and its fracture
presenting an entire want
of cleavage, with its glassy
lustre, sufficiently distin-
guish it. The garnet is the
ancient carbuncle. When
clear-colored it is a beauti-
ful gem.

6. To^lrma2^ne is

found in long prisms of 3,
6, 9, or 12 sides, each of

CLASSIFICATION OF THE ROCKS. 57

which is quite generally furrowed lengthwise. It is of
various colors — black, red, green, and even white. The
black crystals are highly polished, have no cleavage, and
break like resin. They are often found as small as a
knitting-needle, and several inches long, radiating in
every direction through the rock which contains them.

II. CLASSIFICATION OF THE MOCKS.

In the earth's crust we find two kinds of rocks, pro-
duced respectively by the action of fire and of water.
The former was poured out from the furnace within
the earth, and the latter spread out by the waters above,
These two agents, fire and water, seem to have worked
jointly in laying the solid foundations. Rocks are di-
vided into three different classes according to their mode
of formation : Sedimentary, igneous, and metamorphic.

(i.) SEDIMENTARY ROCKS.

Sedimentary ffiocks are those which have been
deposited by water. They are arranged in strata or
layers, and are hence sometimes called the stratified
rocks. They comprise the following kinds :

/. Sandstone y which is only consolidated sand, and
may be either siliceous or argillaceous (clayey).

2 . Conglomerate, which is only consolidated gravel
— the conglomerate taking the name siliceous, calcare-

58 LIT SOL OGIGAL GEOLOGY.

ous, or ferruginous (ferrum, iron), from the character
of the sandy paste which cements together its pebbles.
If the conglomerate is composed of rounded pebbles, it
is often styled a "pudding stone;" if of angular frag-
ments, a " breccia " (bret'-cha). The Potomac marble,
seen in the capitol at Washington, is a very beautiful
calcareous breccia.

3 '. Shale* or argillaceous rock, which is composed
mainly of clay, and separates easily into thin, fragile,
irregular plates.

, which consists of shells, coral, etc.,
pulverized by the waves or precipitated from water hold-
ing lime in solution.

Scenic Description. — Sandy regions, from
the shifting character of the material, must be some-
times abruptly uneven and irregular, and may, there-
fore, occasionally afford a pleasing diversity ; the tend-
ency, however, is to a flat and monotonous surface.
Shaly, and especially slaty formations, consisting usu-
ally of harder and softer layers, which weather unevenly,
present oftentimes wild ravines and picturesque water-
falls, as in the Watkins Glen, near Seneca Lake, N. Y.
The streams cut deep channels and make abrupt
plunges with unaccountable leaps, while the tops of the
hills form escarpments with sharp edges. When the
clay shale is more uniform, it presents a scenery less
picturesque, but not less beautiful. Gracefully contoured
hills and grass-carpeted meadows in wide-spreading
valleys mark the softer aspects of the rural landscape.

CLASSIFICATION OF THE ROCKS. 59

(2.) IGNEOUS ROCKS.

Jgneous ^Rocks are those which have been thrown
out in a melted state. They are usually not arranged in
layers, and are hence termed the unstratified rocks.
They are divided into two classes — trap and volcanic
rocks.

/. Trap ffiocks are so called from the Swedish
word trappa, stairs, because they frequently occur in
terrace-like bluffs, in the form of massive steps. They
are generally black or of a dark color, often with shades
of green or brown. Their hardness renders them very ser-
viceable in paving and " macadamizing " roads, for which
purpose they are largely used. Their dull and unattrac-
tive hues, and the difficulty of dressing them into shape,
unfit them for general purposes. They are, however,
very appropriate for Gothic edifices on account of the
appearance of age which they give. There are four
common varieties of the trap-rock.

(a.) BASALT is also called dolerite (doleros, deceptive),
because of the difficulty in distinguishing its constituent
minerals. These are principally augite and feldspar. It
sometimes contains, scattered through it, crystals of a
bottle-glass green color, called chrysolite (olivine). When
the rock weathers, these little grains fall out. They may
be distinguished from glass by having a cleavage. They
are used as gems, though they are quite soft and have
little lustre.

(K) GREENSTONE — known sometimes as " ironstone"—

LITHOLOGICAL GEOLOGY.

FlG. II.

is also called diorite (dioros, distinct), because its com-
position is so readily determined. It consists of horn-
blende and feldspar. Most of the trap -rocks of the
Eastern States are diorite.

(c.) PORPHYRY (porphura, purple) is so named from
a purple variety which was highly prized in Egypt. It

consisted of a red feldspar
with rose-colored crystals
scattered through it. It
was susceptible of a high
polish, and was very en-
during, hence it was much
sought after by the an-
cients, who wrought it
into sepulchres, baths,
obelisks, etc. Any trap-
rock in which the feld-
spar is disseminated in
distinct crystals is said
to be porphyritic.

(d.) AMYGDALOID
(amygdala, an almond) is
a name applied to trap-
rocks containing cavities
often filled with quartz,
calcite, etc., so that a
weathered surface of the
rock appears like a cake
stuck full of almonds.

Lava (Scoria), in part turned into an
Amygdaloid.

Scenic Description.— The most striking char-
acteristic of the trap-rocks is their Columnar struc-

CLASSIFICATION OF THE ROCKS. 61

ture.* They are crystallized into prisms more or less
regular, with from three to eight sides, a diameter of
from one inch to many feet, and a height often of sev-
eral hundred feet. These pillars are frequently jointed,
and the sections are concave at the top and convex at the
bottom. The columns often stand perpendicularly, and
when broken and disintegrated by the action of the
weather or of the sea, present picturesque appearances
as of old castles and of ruined fortifications. Some
of the most remarkable scenery in the world is of this
character. Fingal's Cave, Isle of Staffa, and the Giant's

FIG. 13.

Fingal's Cave. (From a Photograph.)

* We suppose that the columnar structure of trap-rocks has resulted from a
port of crystallization while cooling under pressure from a melted state, for two
reasons : 1, similar columns are found in recent lavas ; and, 2, from experiment.
Mr. Watt melted 700 Ibs. of basalt, and caused it to cool slowly, when globular
masses were formed, which enlarged and pressed against one another until reg-
ular columns were the result.

This can be illustrated by putting balls of putty into a vessel, and gently pressing

62 LITHOL OG 1C AL GEOLOGY.

Causeway* in the north of Ireland, are familiar exam-
ples. On the north shore of Lake Superior, among the
Palisades on the Hudson, upon Mts. Tom and Holyoke,
Mass., along the banks of the Columbia Eiver, and the
Penobscot in Maine, are presented many similar scenes.
Trap-rocks, when weathered, acquire a dull, dark brown
appearance, and are often colored with patches of white
lichens. There are cases of the existence of basalt in
well-defined flows, which still adhere to craters visible at
the present day, and in regard to the igneous origin of
which there can be no doubt. One of the most striking
examples of a basaltic crater is that of La Coupe in the
south of France. Upon the flank of this mountain, the
traces left by the current of liquefied basalt are still seen
occupying the bottom of a narrow valley, except at those
places where the river Volant has cut away portions of
the lava. Trappean regions abound in perpendicular
walls, sharp ascents, and abrupt precipices. The erup-
tive masses often rise from amid level plains, while hard
dikes alternate with rich strata which decompose into

upon them, when they will be seen to arrange themselves in five and six-sided
columns, precisely similar to the five and six-sided columns of Staffa or the
Giant's Causeway.— Page.
* Hogg, the " Ettrick Shepherd," thus graphically refers to these grandeurs

of Nature :

"Awed to deep silence, they tread the strand
Where furnaced pillars in order stand ;
All framed of the liquid burning levin,
And bent like the bow that spans the heaven ;
Or upright ranged, in wondrous array
With purple of green o'er the darksome gray.
The solemn rows in that ocean den
Were dimly seen like the forms of men ;
Like giant monks in ages agone.
Whom the god of the ocean had seared to stone ;
And their path was on wondrous pavement old
In blocks all cast in some giant mould."

CLASSIFICATION OF THE ROCKS. 6$

fertile soils. The soft plain ascends often at one stride
into a hill fantastically rugged ; and bare, fractured
precipices overtop level fields and terraced slopes rich in
verdure.*

2 . Volcanic ffiocfcs are of two common varieties.

(a.) TRACHYTE (trachus, rough) is so named because
of its rough, gritty feel. It is porous, has a white, gray,
or black color, and is usually porphyritic. It is abundant
in South America — the colossal Chimborazo being a lofty
trachytic cone — in the extinct volcanic regions of the
west, on the banks of the Ehine, and in France.

(b.) LAVA is a term applied to all melted matter
observed to flow in streams from volcanoes. It consists
almost entirely of augite (pyroxene) and feldspar, f The
former constitutes dark colored, and the latter light col-
ored lava. When cooled, the upper part of the stream
is light and porous as a sponge, from the expansion of

* Hugh Miller has mentioned the curious fact that all, or nearly all, the noterf
Scottish fortresses are built upon trappean rocks. Thus the early geologic
history of a country seems typical of its subsequent civil history. A stormy
morning, during which its strata have been tilted into abrupt angles and yawn-
ing chasms, is generally succeeded by a stormy day of fierce wars, protracted
sieges, and all the turmoil of human passion. Amid the centers of disturbance,
the natural strongholds of the earth, the true battles of the race have been
fought. Greece, the Holy Land, the Swiss Cantons, Scotland, New England,
all have been grand theatres alike of geologic and of patriotic strife.

t Other simple minerals occur in lava. At least 100 species have been de
tected in that of Vesuvius, but they bear so small a proportion to the whole
mass as to render it incompatible with the design of this work to devote spac*
to them here. There are al 10 thrown out from volcanoes " fragments of gran-
ite and other rocks scarcely altered ; cinders and ashes of various degrees of
fineness, which are sometimes converted into mud by the water that accom-
panies them ; also sulphur in a pure state ; various salts and acids ; and several
gases, among which are the hydrochloric, sulphurous, and sulphuric acids ;
alum, gypsum, sulphates of iron and magnesia, chlorides of sodium and potas-
sium, of iron, copper, and cobalt ; chlorine, nitrogen, sulphuretted hydrogen/1
eta.— Hitchcock.

LITHOLOGICAL GEOLOGY.

the steam bubbles, and will swim in water, while the lowei
portions are hard and compact like the ancient basalt.
The porous lava is called scoria. Pumice is a feldspathic
scoria with long, slender air-cavities, drawn out by the
forward movement of the lava stream; large quantities
of it are often found floating in the ocean. It is much
used in polishing marble. Obsidian is a glassy-like lava.

Scenic Description.— Regions of frequent vol-
canic action contain cones and craters surrounded by
beds of lava and scoria. These features are well exhibited
in the accompanying view of a scene near Mono Lake,
Sierra Nevada region.

FIG. 15.

Volcanic Cones, near Mono Lake.

(3.) METAMORPHIC ROCKS.

Jtfelamorphic ffiocfcs are those which have been
altered by heat, moisture, and pressure. Lava penetrating

CLASSIFICATION OF THE ROCKS. 67

sedimentary rocks would materially modify their char-
acter ; the clay would be changed to slate, the limestone
converted into marble, earthy sandstone and clay rocks
into granite-like rocks, and the impurities crystallized
into various minerals.* The stratification would be de-
stroyed, and the fossils in part, if not entirely, obliter-
ated. Sometimes, however, the original fossils may be
still distinguished. There is a kind of marble found at
Kilkenny which contains shells of the ammonite. They
look exactly like the prints of a cureless heel, and many a
housekeeper has wearied herself in vainly trying to scour
out these fossil remains. The famous Carrara marble is a
metamorphic limestone. On examination with a lens it
reveals spangles of graphite, and frequently nodules of
ironstone lined with perfectly limpid crystals of quartz.
These accidental defects, resulting from impurities in the
limestone, are very annoying to the sculptor, since noth-
ing in the exterior of a block betrays their existence.

/. Granite (from granum, a grain, because of its
granular structure) consists of feldspar,, inica, and quarjbz.
The feldspar shows a smooth surface of cleavage in two
directions, and is usually of a white or flesh color ; the
mica may be readily recognized by its glistening look,

* In Whitney's Geological Survey of California, constant illustrations are
given of the effects of metamorphism. Places were found where the line of
separation between the sedimentary and metamorphic rocks is sharply drawn.
Near the junction of the two kinds, the latter seem to have Detained their origi-
nal stratification. Patches of sedimentary rocks which entirely escaped the
igneous action are inclosed in the metamorphic rocks. Here is a layer of
quartz, which beyond is converted into jasper ; a clayey sandstone into set.
pentine, or into mica slate with disseminated garnets. The metamorphic and
sedimentary rocks give each a distinctive character to the landscape. The
former furnish hills of sharper outline, richer soil, and more abundant vegeta-
tion, so as to be readily recognized even at a distance.

LITSOLOGICAL GEOLOGY.

FlG. 16.

Graphic Granite, Berkshire, Mass,

and by being easily separated into thin layers ; the
quartz has a glassy lustre and no cleavage. Graphic
granite is a variety in which the quartz is imperfectly
crystallized into long, slender crystals. When the rock
is broken crosswise, the
ends of these crystals pre-
sent forms somewhat re-
sembling Hebrew charac-
ters. Sometimes granite
has a very coarse struc-
ture, the crystals being a
foot or more in diameter ;
at other times it is so fine
that one can with diffi-
culty distinguish the con-
stituent minerals. When sound, it is an excellent build-
ing stone, but does not merit the character of extreme
hardness which is proverbially ascribed to it. Its granu-
lar texture unfits it for road-making, since it is crushed
into dust so readily by tramping feet. In the Crimean
war it was shown that granite ramparts were as easily de-
molished as those of limestone. Granite seems to be the
lowest rock in the earth's formation, and yet, strangely
enough, it is found on Mt. Blanc — the highest in Europe,
and crowns many of the Rocky Mountains.

Granite is quarried in great quantities in the East-
ern States for building purposes. New Hampshire and
Massachusetts are noted for their extensive beds. They
may be called the Granite States of the Union. The
granite is detached in blocks by drilling a series of
holes, one every few inches, to a depth of three inches,
and then driving in wedges of iron between steel cheeks.

CLASSIFICATION OF THE ROOKS. 69

In this manner, masses of any size are split out. There
is a choice of direction, as the granite has certain direc-
tions of • easiest fracture. Masses 120 feet in length have
been obtained at some of the quarries. Granite was
highly prized by the ancients. There are granite obel-
isks in Egypt which have stood for 3,000 years. Pom-
pey's Pillar and several of the principal Pyramids are
composed of this material.

FORMATION OF GRANITE. — Granite is often styled the
primitive rock, since it seems to be the one which consti-
tutes the basement of the earth's crust. Though it may
now lie at the foundation, it may still be a metamorphic
rock, and not the first product of the slowly cooling
globe. It is more likely that most of the granite rocks
have resulted from the wearing down of the primeval
crust of true igneous rocks. These were carried into
the sea and deposited as stratified rock. Buried after-
ward beneath vast accumulations of other rocks, by the
internal heat and the influx of hot water charged with
various chemical agents,* they were crystallized, and
their fossils and stratification obliterated. Again, they
may have been worn by the sea, deposited, and afterward

* In the account given of the Pluton Geysers, California, we seem to have an
insight into the laboratory of the world, and can learn something of the chemi-
cal changes which have been going on in past ages. These geysers are hot
springs, which throw out intermittingly and spasmodically powerful jets of
steam and scalding water, their temperature varying from 93° to 169° P. The
water contains sulphuric acid, sulphuretted hydrogen, and probably other active
solvents. The rocks are rapidly dissolving under this powerful metamorphic
action. Porphyry and jasper are transformed into a kind of potter's clay. Trap
and magnesian rocks are consumed, much like wood in a slow fire, forming sul-
phate of magnesia and other products. Granite is rendered so soft that one can
crush it between his fingers as easily as unbaked bread. The feldspar is con-
verted partly into alum. The boulders and angular fragments brought down the
ravine by floods are being converted into a firm conglomerate, so that it is diffi-
cult to dislodge even a small pebble, the pebble itself sometimes breaking before
the cement will yield.—- Sfiepherd, Am, Journ, qf Science*

70 L1TBOLOGICAL GEOLOGY.

metamorphosed. How many times this cycle of change
has taken place, we have no way of judging. The entire
crust of the enrth has doubtless undergone metamorphic
action, to some extent at least, and is unlike what it was
when created. What made up that primeval crust we do
not know, and hence cannot tell whether any of the
ancient formation survives. It is generally believed that
granite could not be produced directly by the cooling of
the melted lava that then composed the globe. There
are, however, places where it has been found at a great
depth, and, by some powerful convulsion, has been ejected
to the surface in a melted state, like a true igneous rock.
It may even now be in the process of formation in the
lower portions of the earth's crust. It is certain that as
the crust wears away above, new rocks must be cooling
underneath, since the point of fusion is constantly pass-
ing downward. Granite has, however, been formed in all
ages of the world, and cannot be thought a primitive
rock merely, although specially characteristic of the
earlier periods. We shall, therefore, consider it, in gen-
eral, as a metamorphic rock crystallized by the combined
action of heat, water, and other chemical agents, from sedi'
mentary or more ancient rocks.

Scenic Description. — The ancient granite,
having been exposed for so long a time to the wear of
the elements, rarely imparts boldness or grandeur to the
landscape, unless more recent convulsions have broken it
up and rendered it picturesque. When containing little
feldspar, and being therefore more durable, it forms lofty
pyramidal peaks of sharp outline that rise in enormous
Bpires, as in the vicinity of Mt. Blanc. There seems to

CLASSIFICATION OF THE ROCKS. H

be often a tendency to rounded concentric outlines,*
which render the view sombre and uninteresting. The

FIG. 17.

North Dome— Yosemite Valley.

peculiar dome-like appearance of granite mountains is
beautifully illustrated in the magnificent scenery of the

* Humboldt says : " All formations are common to every quarter of the globe,
and assume the like forms. Everywhere basalt rises in twin mountains and
truncated cones ; everywhere trap porphyry presents itself to the eye under the
form of grotesquely shaped masses of rock ; while granite terminates in gently
rounded summits." As the pupil will observe, however, this latter is but one
of the aspects which trranite present*.

72 LITHOLOGICAL GEOLOGY.

^Yosemite. Its colossal peaks are of solid granite, the
^ North Dome being 3568 feet in height. Granite forms,
in general, lofty hills and elevated table-lands, which are
rendered still more bleak and forbidding by the snow-
clad peaks of the more elevated mountains. The soil is
generally scanty and barren. The clay from the decom-
posed granite is the finest and best that can be found ;
the sand, often of the purest white, always lustrous and
bright. As a result, the landscape wears a peculiar
aspect of purity.* It cannot become muddy, foul, or
unwholesome. The streams may indeed be opaque and
white as cream with the churned substance of the weath-
ered granite ; but the water is good and pure, and the
shores not slimy nor treacherous, but pebbly or of firm
and sparkling sand. The quiet springs and lakes are of
exquisite clearness, and the sea, which washes a granite
coast, is as unsullied as a flawless emerald.

2. Gneiss (nice) differs from granite only in being
stratified. Indeed, the two kinds of rock pass into each
other so insensibly that they are often difficult to dis-

* It is remarkable how this intense purity in the country seems to influence
the character of the inhabitants. It is almost impossible to make a cottage built
in a granite country look absolutely miserable. Rough it maybe, neglected,
cold, full of aspect of hardship, but it never can look foul ; no matter how care-
lessly, how indolently its inhabitants may live, the water at their doors will not
stagnate, the soil at their feet will not allow itself to be trodden into elime ; they
cannot so much as dirty tbeir faces or hands if they try. Do the worst they can,
there will still be a feeling of firm ground under them and pure air about them,
and an inherent wholesomeness which it will need the misery of years to con-
quer. The inhabitants of granite countries have, too, a force and healthiness oi
character about them, abated or modified according to their other circumstances
of life, that clearly distinguish them from the inhabitants of less pure di»-
tricts.— Euskin.

CLASSIFICATION OF THE ROCKS. 7$

tinguish.* Its origin, therefore, is doubtless the same as
that of granite, both being made from stratified rocks ;
when the stratification entirely disappeared, granite being
the result ; and when only partially or not at all, gneiss.
Because of the ease with which it divides into thin layers,
this rock is much used for flagging.

Scenic Description. — In our own country we
find much of the grand scenery of the White Moun-
tains, Blue Eidge, and Rocky Mountains, among rocks
of this formation. Hugh Miller, humorously speaking
of the gneiss hills of Scotland, says : A gneiss hill is
usually massive, rounded, broad of base, and withal
somewhat squat, as if it were a mountain well begun,
but interdicted somehow in the building, rather than a
finished mountain. It seems almost always to lack the
upper stories and the pinnacles. It is, if I may so ex-
press myself, a hill of one heave ; whereas all our more
imposing Scottish hills — such as Ben Nevis and Ben
Lomond — are hills of at least two heaves ; and hence in
iourneying through a gneiss district, there is a frequent
feeling on the part of the traveler that the scenery is
incomplete, but that a few hills, judiciously set down
upon the tops of the other hills, would give it the

* Doubtless* some gneiss has been formed by the action of water, and is per-
haps a sedimentary rock. Thus granite being worn away by the waves, the
granite debris would be deposited in regular strata at the bottom of the sea,
constituting gneiss. Most of it is, however, the product of an incomplete meta-
morphic action, which, if made complete, would have produced true granite by
destruction of all fossils and stratification. Thus Dawson, in his Acadian
Geology, says that in Nova Scotia, near the Nictaux river, there are beds of
blate in which the granite has been intruded, and the slates near the junction
have been altered into gneiss containing garnets. Here is a case of clear meta-
inorphism of shale into gneiss.

74 L1THOLOG10AL GEOLOGY.

proper finish. No hill, however, accomplishes more with
a single heave than a gneiss one.

. 3. Mica Schist is a gneiss rock, consisting mostly
' of mica. The dust in the roads of places abounding in
this rock is full of the fine glistening particles of mica.

Scenic Description.— The scenery of regions
where mica schist predominates is bold, rugged, and
unfertile. Thrown into lofty mountains by the pro-
truding granite, and often tilted in nearly vertical posi-
tions, they present that rugged and abrupt aspect so
characteristic of the Scottish highlands and some of
the mountain ranges of our own country. Loch Kat-
rine and many other places, classic for their picturesque
beauty, owe their origin to the peculiarities of this for-
mation. Hugh Miller says: "Their gray locks of silky
lustre are curved, wrinkled, contorted, so as to remind
us of pieces of ill-laid-by satin, that bear on their crushed
surfaces the creases and crumplings of a thousand care-
less foldings."

. <£. Syenite is a granite in which the mica is re-
) placed by hornblende. It is so called from the city
of Syene, Upper Egypt, where the ancient Egyptians
quarried it for monumental purposes. The granite found
near Aberdeen, Scotland, and extensively imported into
this country, is of this class. It possesses great strength,
a half-inch cube requiring to crush it, a pressure of
24,556 pounds. The celebrated Quincy granite is also a
syenite. Many public edifices are built of this stone;
for example, the Bunker Hill monument, the custom-

CLASSIFICATION OF THE ROCKS. 75

houses at Boston and New Orleans, and the Astor House
in New York.

5 '. Quarlzite is a rock composed of quartz sand
cemented by heat. In a quartz district, because of the
slow weathering, the hills present a scenery of savage
wildness, but wonderful grandeur.

6. Marble is metamorphosed limestone. The dif-
ferent varieties have already been described on page 51.
Limestone is one of the rocks in which the metamor-
phic action can most easily be traced. When not thus
modified we find it as common limestone, chalk, etc.
By heat its character is entirely changed ; it takes on
a crystalline structure, its color is varied, the fossils are
generally destroyed, and the various impurities form new
minerals which often fill the veins of the marble with
beautiful colored figures, as seen in the variegated mar-
bles of California.

There are also other varieties of metamorphic rocks,
viz., talcose schist, a slate which contains much talc, chlo-
rite schist, one which contains chlorite (an olive-green
mineral very like talc), and slate rock, which passes almost
insensibly into an argillaceous or clayey shale.

m. STRUCTURE OF THE ?KOCKS.

The rocks of the earth's crust are divided according
to their structure into two classes, the stratified and the
unstratified rocks. The former are arranged in layers,
the latter are not. The former were generally produced

76 LITHOLOGICAL GEOLOGY.

by aqueous, the latter by igneous agencies. The former
mark the periods of rest in the world's history, the lat-
ter chronicle its convulsions. Upon the exterior of the
crust the stratified rocks are largely in excess, occupy-
ing probably Jg of the surface; upon the interior, how-
ever, the unstratified comprise the whole mass, and ex-
tend to a depth of perhaps 50 miles. Historical geology
deals almost entirely with the stratified rocks, and nearly
all of its principles are based upon facts which they dis-
close.

(i.) STRATIFIED ROCKS.

As soon as dry land was formed, it began to be worn
away by the ceaseless action of the rain and the restless
sea, depositing the debris at the bottom of the ocean.*
Thus, while the earth's crust has been growing from
below by the formation of unstratified, it has been grow-
ing above by the formation of stratified rocks. These
materials are arranged in comparatively flat layers as in
Fig. 18. In this way the earth would be covered over
by successive deposits like the coats of an onion.

FIG. 18.

Sea

/. dislocations of Strata. — Had these wrap-

* It is probable also that submarine volcanoes poured their liquid streams
into the primeval ocean. These materials were worked over and deposited as
stratified rocks. The earliest strata, says Agassiz, are pierced with numerous
funnels, which were outlets for the fierce floods beneath.

STRUCTURE OF THE ROCKS.

pings remained undisturbed, we could have made little
progress in deciphering their history, since we have not
pierced the crust much more than half a mile in perpen-
dicular line. But by igneous action, the rocks which
would have lain as in Fig. 18 have been upheaved, and
present a form similar to that shown in Fig. 19, where

FIG 19.

we can examine, on the top, the edges of various sedi-
mentary strata, and also the igneous rocks which were
hidden below. Oftentimes the geologist, in tracing the
course of a river, will find successive strata tilted up on
edge, presenting the appearance represented in Fig. 20.

FIG. 20.

Here, had the rocks remained in their original position,
the river in its descent might not have disclosed more
than two or three layers ; now, by the outcropping, as it
is termed, many successive strata can be examined often-
times within a few miles.

LITHOLOGICAL GEOLOGY.

2. ^Definitions. — A stratum includes one or more
layers, or laminae, of any particular kind of rock. A for-
mation is composed of several strata which were deposited
in the same period. A group is a part of a formation,
including such strata as are in any way related to one
another. The laminae, or layers, of a group bear the same
relation to one another that the groups of a formation do.

In Fig. 21 the strata at A are said to be horizontal,

FIG. 21.

those at B inclined (and the angle which they form
with the horizon is called the dip), those at E to be
tilted up, at C to be vertical, and at D to be contorted.
In Fig. 22, strata dipping in opposite directions, «, are

FIG. 22.

called anticlinal; when dipping toward each other, s,
synclinal ; e is an escarpment or a bluff; strata, as c,
coming to the surface, are called an outcrop ; strata
arranged regularly above one another, as at o, are said

STRUCTURE OF THE ROCKS. 79

to be conformable; those not, as at x, are styled un-
conformable.

3. ^Diverse Stratification. — Sedimentary rocks
were not always originally deposited in horizontal layers.

FIG. 23.

Diverse Stratification.

Along the sea-shore we can see the deposits being made
on its sloping bottom. The ebb and flow of the tide, the
sand blown by the wind, and the action of the waves,
which often undermine one part and elevate another,
may cause a rock to present the diverse stratification
seen in Fig. 23.

£.. lamination. — It is necessary to distinguish be-
tween stratification and lamination. Separate laminae,
as well as strata, indicate a pause in the process of depo-
sition, whereby the sediment had time partially to harden.
The former denote a shorter time, so that the laminae,
in general, do not easily separate from each other. In
some stones it requires as much force to split them
along the planes of lamination as "across the grain."
The different kinds of lamination are instructive, since
they indicate the circumstances under which the rock

LITHOLOGICAL"~QEOL 0 G T.

was formed. Quiet deposition always produced parallel,
slowly rippling waves, curved, and pressure, contorted,
lamination.

J. J^autts*— Vertical cracks or seams frequently trav-
erse the rocks, and the strata on one side slipping away
from those on the other, the layers on the two sides do
not correspond. During the unequal movements which
have produced the dislocation, the edges have often
ground together so as to become polished and grooved.
Fig. 24 represents a series of faults, offsets, as they are
called, in the iron mine at Mt. Pleasant, N. J.

FIG. 24.

Faults (offsets) in Mt. Pleasant Iron Mine, Rockaway, N. J.

6. Jointed Sh*ucture. — "When these vertical cracks
are parallel to one another, and, in addition, a second
system crosses the first at right angles, the rocks are
divided into regular blocks, forming a jointed structure.
On Cayuga Lake the rocky bluffs resemble fortifications

STRUCTURE OF THE ROCKS.

with towers and bastions. Joints in the rocks are almost
invaluable to the quarrymen. It would be a most dim-
cult task indeed to quarry a rock destitute of stratifica-

FIG. 25.

Jointed Structure, Cayuga Lake.

tion and joints. These seams have doubtless been pro*
duced partly by shrinkage as the earth has cooled, and
partly also by long-continued lateral pressure consequent
upon movements of the earth's crust. The fact that the
joints of any region are ^arallel to one another indicates
a common origin.

7. Folds. — Strata are often so folded upon one an-
other that it is difficult to decide upon their relative age.
Huge mountains consist of rocks twisted and contorted
as if they had been "crumpled up" by some mighty
hand. Fig. 26 represents a section of slate 1000 feet
long and 300 feet high, taken in the coast ranges of
California. After these were deposited as sediment, they
were crushed together and bent over by steady lateral

LITHOLOGICAL GEOLOGY.

pressure.* " How prodigious the force which could fold
the rocky strata of a mountain as one would the leaves

FIG. 26.

FIG. 27.

Flexures in Slate, Coast Range, California.

of a book/' After rocks have been folded in this man-
ner, the top has often been removed by denudation^
i. e.9 the action of water, leaving parallel strata standing
on edge, the older or lower being above the newer.
Thus, in Fig. 27, if the
fold were swept off down
to the line D E, there
would be no appearance D
of anything more than a
mere tilting up of the ABC ABC

A Decapitated Fold.

strata; yet the layer A

would lie above C, when it was really deposited be-
low it.

* Lyell illustrates the effects which pressure would produce on flexible strata
by laying several pieces of cloth upon one another in a pile, and then placing a
book on top ; apply other books at each end and force them toward each other.
The folding of the cloth will exactly imitate the folding seen in the rock strata.

t Near Chambersburg, Pa., there is a fault 20 miles in length, and the depth of
the dislocation is 20,000 feet, and yet a man can stand with one foot on one side
of this fracture and the other foot on the other side. What has become, then, of
this immense mass of material 20,000 feet in height It must have been swept
into the Atlantic by the denuding flood. If this had not been done, a bold
precipice would have stood there nearly four miles in height and twenty
miles in length. Long ages must have been required for water to effect such a
denudation. —Lesley,

STRUCTURE OF THE ROCKS. 83

8. Concretions are rounded nodules formed by the
tendency of matter to collect about a center. They are
usually flattened, though they are sometimes quite spher-
ical. At the center there is most commonly some foreign
object, a fossil, shell, twig, or the like, which was the
nucleus of the crystallization. In some iron mines are
found balls of ore, which, from their peculiar form,
are termed "kidney shaped." Calcareous concretions,
washed up by the waves, abound along the shores of
Lake Erie. They have been found as large as six feet
in diameter. They sometimes have the shape of large
sea-turtles, and the cracks formed by shrinkage often re-
sembling the plates of the shell, they are considered by
the neighboring people as petrified relics of that animal.
On the coast of Durham, England, the magnesian lime-
stone forms bold cliffs, which look as if made up of irreg-
ularly piled cannon balls. When the internal cracks
formed in drying have become filled with spar, the con-
cretions are termed septaria (septum, a division), and,

FIG. 28.

Claystone, Springfield, Mass.

when cut and polished, present an ornamental appear-
ance. They are so abundant as to be used in making the

84 L1TKOLOG1CAL a $ 0 L 0 G Y.

famous Eoman cement. In beds of clay containing con-
siderable carbonate of lime are found peculiar concretions
called claystones. They are popularly supposed to be
worn by the water. They often assume most fantastic
shapes, resembling familiar objects, such as a hat, bird,
ring, etc. A variety of limestone composed of minute
concretions, often as small as a grain of sand, is termed
oolitic (see Fig. 7). Along the limestone bluifs of the Mis-
sissippi beautiful " geodes " are found. Externally they
are merely rough stones, but a blow of the hammer re-
veals the interior lined with delicate quartz crystals.*
Fig. 29 represents iron nodules, found in coal mines,

FIGS. 29-32

Ironstone Nodules, showing Varieties of Central Nuclei.

with their central nuclei — No. 1, a fragment of a plant ;
2, a fish-tooth ; 3, a coprolite (fossil excrement) ; and 4,
a septarium, with curious partitions of white carbonate of
lime, giving the section the appearance of a beetle; from
which circumstance such nodules are known in some
places as beetle stones.

* " Water is sometimes found in the geodee, holding the silex in solution,
and making with it a milky looking mixture. As the water evaporates, the
silex has been known suddenly to form into delicate crystals. Such geodes
were at one time abundantly found on Briar Creek, in Scriven or Burke County,
Ga., in a rock composed of hornstone and jasper; the milky fluid contained in
them was used by the inhabitants as a paint or whitewash." — Am. Journal of
Science.

STRUCTURE OF THE ROCKS.

9. Slate Structure. — This term is commonly ap-
plied to any rock which splits into thin layers. The true

FIG. 33-

Section exhibiting Lines of Cleavage.

slate, however, splits in layers transverse, often at right
angles to the strata. Such rocks have been changed from
clay shales by metamorphic action, in which process they
have been hardened and partially crystallized, while at
the same time they have been submitted to long-con-
tinued lateral pressure. Prof. Tyndall has shown that
even soft clay will in this manner divide into thin
laminae.

( 2. ) UNSTRATIFIED ROCKS.

The unstratified rocks are found as shapeless masses
underlying, overlying, and sometimes penetrating the
stratified rocks.

/. ^Definitions.— In Fig. 34, C is an underlying
mass of granite, e is a stratum forced between two

FIG. 34.

c B A

strata of sedimentary rocks, d is an overlying mass, and

LITHOLOGICAL GEOLOGY.

A simply a mass thrown up from below, and disrupt-
ing the regular stratified rocks above it. In Fig. 35,

FIG. 35.

at c is a fault in the rocks, and the joint at that point
filled with igneous rock is called a dike. At a is a series
of veins traversing a stratified and an unstratified rock.

2. Veins are fissures in the rock strata, filled with
crystallized mineral matter, such as fluor spar, quartz,
etc. They are of all sizes, from an inch to many feet
in thickness. We often find rocks and even pebbles
crowded with veins sometimes not thicker than a sheet
of paper (see Fig. 39).

3. 1)ifces are wide fissures filled with igneous rocks
or recent lava. They are generally larger than veins,
have their sides more nearly parallel, ramify less com-
monly in branching veins, and contain but a single kind
of rock. In Fig. 36 is a representation of modern dikes
near Mt. Etna. The term dike means a wall. It is de-
rived from the fact that the trap is generally harder than
the adjacent rock, and hence disintegrates more slowly
when exposed to the elements. The dike thus projects
above the surface like a wall, often traversing the coun-
try for many miles. Hugh Miller, in speaking of the

STRUCTURE OF THE ROCKS. 87

FIG. 36.

Modern Dikes near Mt. Etna.

scenery about Edinburgh, compares the denuding influ-
ences to the work of the sculptor; as he brings out his

FIG. 37.

Trap Dike, Lake Superior.

L1TBOLO QIC AL GEOLOGY.

FIG. 38

figures in relief by cutting away about them, so Time
scoops away the sand rock and shale, and leaves the bold,
rugged features of the trap ridges.
When veins cross each other, it is easy to decide

upon their relative
age, the one which
is separated being
necessarily the older.
Thus in Fig. 38
there is a trap-dike
protruding through
a bed of gneiss, and
crossing that is a
vein of quartz, a b.
Prof. Hitchcock de-
scribes a block of greenstone which exhibits eleven series
of veins.

Dike.

a b. A Quartz Vein passing through a Greenstone
Dike and Layers of Gneiss.

<£. Origin of Veins and 2>i£es.—Wl\en the
rocks cooled from a melted, or dried from a moist state,
they naturally shrank so as to form cracks or seam?
of varying size. In different ways Nature collected
material to fasten the rocks together again. Some clefts
were filled by melted rocks injected from below, and then
cooled. This is known, because the adjacent rocks are
metamorphosed by contact with the burning mass, and
wear a different look from the rest, while the mass itself,
by its crystallization, shows that it cooled sooner on the
outside against the walls than at the center. Dikes pass-
ing through beds of chalk in the county of Antrim, in
the north of Ireland, have changed the chalk to mar-
ble. Some seams were filled by chemical processes with

SVRVCTVRfi OF T&JS ROCKS. 89

matter which crystallized out from the adjacent rocks,
as, for example, a plaster rock dark and muddy is often
found crossed with layers and filaments of white; trans-
parent selenite crystals, which have doubtless been formed
from the parent stone. The larger number, however, of
these rents were mended with rock material from highly-
heated water charged with mineral matter.* This water
filtering through the finest seams of the rock would fill
them with a crystalline paste. We often see this process

FIG. 39.

Vein-form Pebble from Drift, Elmira.

* Large rocks are sometimes as full of veins as your hand is, and of veins
nearly as fine (only a rock-vein does not mean a tube but a crack). These clefts
are mended usually with the strongest material the rock can find, and often
literally with threads ; for the gradually opening rent seems to draw the sub-
stance it is filled with into fibers which cross from one side to the other, so
that when the crystals become distinct, the fissure has often the look of a rent
brought together with strong cross stitches. When all has been fastened, a new
change of temperature may occur, and the rock contract again. The old vein
must open and a new one be formed. If the old one be well filled the cross
stitches will be too strong to break, so that it can only give away at the sides
and thus this space being filled afterward, a supplementary vein is added. In
this manner three or four parallel veins have been made.— Buskin.

LITHOLOGICAL GEOLOGY.

FIG. 40.

beautifully illustrated
in an opaque uncrys-
talline rock, and in
pebbles threaded with
fine crystalline veins
of a different variety.
(Fig. 39.) Veins are
often rich in metallic
ores. Sometimes the
metal in such cases
has been sublimed by
heat below, and car-
ried up either with
steam or melted mat-
ter, and deposited in
the rock fissures
above. In the figure
is shown a valuable
vein of lead-ore for-
merly worked at Kos-
sie, N. Y. This is
the simplest form of
a metallic vein (lode),
as it is a mere vertical
sheet. Like most me-
tallic veins, it is doubt-
less an aqueous de-
posit, the material
being derived from the
surrounding rocks.

Lead Vein 01 Rossie, N. Y.

ff The crust of our earth is a great cemetery, where the rock*
are tombstones on which the buried dead have written their
own epitaphs." — ACU.SSIZ.

THE history of the formation of the earth's crust is
not yet fully written. In its investigation many diffi-
culties are met. Strata were not made over the whole
earth at the same time, so that the coatings of rock are
not uniform. Again, some are found in one section
which are wanting in others, and the same strata even
are composed frequently of diverse material in different
parts of the earth. Thus, the chalk formation of Eng-
land is represented by sandstone, marl and limestone in
this country, though all belong to the same era. It is
therefore a difficult task to put together these scat-
tered fragments. "The world is to the geologist a
great puzzle box." He is to trace the resemblances
and learn how to combine all the widely strewn parts of
the world's history, and to arrange them in order and
symmetry. Experience alone can teach him accurately
to read the rocky leaves of the book of nature. In
this work the fossils are his chief reliance. They have
been well termed the "Medals of Creation," since by
their means the geologist identifies different strata, and

94 HISTORICAL GEOLOGY.

judges of the successive creations of animals and plants
through the ages of the past. As the seals, medals, coins,
etc., found in a ruined city concerning which history is
silent, declare its nationality, so the organic remains of a
stratum determine its geologic period and characteristics.
Each epoch recorded in its rocks and fossils the history
of the life which it supported, and the changes through
which it passed.* Each formation possesses its peculiar
fossils. This similarity obtains in a great degree over the
entire world. Thus, the identification of fossils is the
identification of formations. We can therefore under-
stand with what eagerness these are gathered and pre-
served. Fragments which the ignorant would spurn
from his feet are invested with as high an interest as the
obelisks of Egypt or the sculptures of Nineveh. The
antiquarian pores over those with intensest enthusiasm,
seeking to read the history of a few thousand years. The
geologist bends with equal delight over the forms and
impressions of the rocks, seeking to gather information
with regard to a past, compared to the duration of which
the chronology of man is but as the moments of yester-
day. The print of a leaf, a petrified shell, a tooth, the
fragment of a bone, a fish-scale even, may serve to un-
riddle the most puzzling problem. Eough and mutilated

* " Nature has all her facts stereotyped. She writes her events often upon the
most fragile plants and flowers, on the very winds and waters — all the most
evanescent and changing forms, as well as the most permanent. Her record is
as enduring as the phases of the object upon which she writes, and sometimes,
as if fearing both would be lost, she petrifies the whole, and leaves it thus to
endure for the ages. She has often preserved in stone the history of her frailest
leaves, her most ephemeral and minutest insects and infusoria, the record of her
ebbing and flowing tides, of the piles of dust blown together by her winds, the
footprints of her smallest birds, and of her rain-drops falling upon the sand,"-~

HISTORICAL GEOLOGY. 95

though the fragments may be, to the educated eye they
embody a tale as legible as any sculpture or hieroglyph-
ics, and far more comprehensive. That tiny stem, a
mere discoloration on the rock, once floated as sea-weed
in the waters ; that reed once luxuriated in a primeval
marsh; that delicate rock impression was a fern that
once waved in the sunshine ; and that simple leaf, now
only a film of coal-like matter, sparkled with the dew of
heaven as certainly as the tender herb is cherished by the
dew to-day, or existing verdure grows to beauty in the
sunlight. Every trace, then, becomes a letter, every
fragment a word, every perfect fossil a chapter in the
world's history. Each tells of races that lived, multi-
plied and died, of lands that were tenanted, and waters
thronged with life, — so oft repeated, again and again, that
the mind, at first excited by the marvels, at last grows
weary and loses itself in the contemplation of the works
of the Infinite Creator.

There are no sharply-drawn lines between the different
ages. They fade into each other as insensibly as the
mountain blends with the plain. Yet each has a promi-
nent idea, and chronicles a grand transition in the world's
history.* Lesser changes are denoted by Periods, Epochs,
and Groups. Some, at least, of the revolutions marking
the separate ages were nearly if not quite universal.
Those denoting the other divisions were more local in
their character. The periods and epochs are therefore

* The land now lay low in the water, and anon was lifted into arid, moun-
tainous regions. Consequent upon each change was a new set of climatic influ-
ences, winds, ocean currents, rains, etc., each necessarily producing its impress
on the vegetable and animal life of the period. Thus there were pauses, as it
were, in the deposition of sediment, each pause making a break in the strata.

96 HISTORICAL GEOGRAPHY.

not the same in Europe and America. They vary much
in the formations which are represented even on the
Atlantic slope and in the Mississippi valley.

Geological divisions. — The history of the earth's
crust is divided into four great eras or times, known
as the Eozoic (dawn of life), the PALEOZOIC (ancient
life), the MESOZOIC (middle life), and the CE:N~OZOIC
(recent life). These names indicate the successive stages
in the development of life on the globe.

I. EOZOIC TIME.

AGE OF PROTOZOANS.

II. PALEOZOIC TIME.

1. SILURIAN AGE (Age of Mollusks).

2. DEVONIAN AGE (Age of Fishes).

3. CARBONIFEROUS AGE (Age of Coal-Plants).

III. MESOZOIC TIME.

AGE OF REPTILES.

IV. CENOZOIC TIME.

AGE OF MAMMALS.

The table on page 97 contains the various subdivisions
now generally accepted, the lowest in order of time being
placed at the bottom.

PALEOZ
TIME.

OlJ^U IXl^llN /ILVJH,. __

L (Age ofMollusks)

-t
3

>
^

>
}

?c
i 2
^>
|a

I
1

)

|
t

(Age of Coal PI

f CARBONIFERO

O
M

O
5

Pfl

N
O

>
as

1
I

i
i

rjci

£, >

1
1

C/3

P
W

C/3

CA)

£w

5»

Era?

s?c°

O O

o ^

H^O

TSDAM PERIOD.
JRONIAN PERIOD.

URENTIAN PERIO

ENTON PERIOD.

JDSON PERIOD.

AGARA PERIOD.

ZISKANY PERIOD.
>WER HELDERBER
LINA PERIOD.

^PER HELDERBER

\MILTON PERIOD.

LTSKILL PERIOD.
IEMUNG PERIOD.

BCARBONIFEROUS

.RMIAN PERIOD.

LRBONIFEROUS PE

ETACEOUS PERIO
RASSIC PERIOD.
JASSIC PERIOD.

CRTIARY PERIOD.

PI
sj

I-H

Car
Mil

erous E
Grit E

ST-TERTIARY PE
Quaternary Per

?lg Igi

TO O O 2.3 3

33S EfB

wl° Sg-i

98 HISTORICAL GEOLOGY.

The ^Duration of Time represented by these
geological periods and epochs we have no means of judg-
ing. Estimating the past, however, by the present rate
of change, it must be immense, so that even if we could
express it in centuries and years, we could form no idea
of the aggregate any more than we can comprehend the
distances that separate our earth from the fixed stars.
This idea of immense duration of time is suggested at
the first examination of the stratified rocks. All that
Geology attempts, at present, is to arrange in regular
order the various stages of progress in the history of
the earth's crust, leaving it for the future to decide
upon the length of the different epochs. As yet we
know only that "time is long" and hence estimate it
by ages, eras, and periods, rarely venturing more than
an occasional hint at their relative duration. There is
an eternity of time as well as of space in which God
works out His almighty plan of creation. Whatever
may have been our preconceived notions, we should
come to the study of Nature with a reverent, teach-
able spirit, seeking to learn its mysteries, to compre-
hend its plan, and to understand the ways of Him
who created all things.

OZOIC §IME.*

Probably none of the original crust of the earth now
survives. If any still exists, it perhaps forms the foun-

* This era was, until lately, universally known as the Azoic (without life).
There was doubtless such a period when the heated earth, swept by a boiling
ocean, was destitute of inhabitants. Recent discoveries, however, seem to

EOZOIC TIME. 99

dation rock, * and is buried deep beneath later deposits
and the ruins of the tremendous changes which have
since occurred-! The oldest rocks now known upon the
surface of the earth probably represent Eozoic Time.
The following periods are recognized : J

T-, , *.. Huronian Period.

Eozoic TIME. \

Laurentian Period.

Both these are named from the localities where they
chiefly occur, viz., the mountains on the N.W. of the
Eiver St. Lawrence, and on the north of Lake Huron.

indicate that the lowest of the so-called Azoic rocks which have actually been
observed, exhibit proof of the existence of life, and the name Eozoic (dawn of
life) has therefore been substituted. Dana does not accept this conclusion,
and, in the revised edition of his Manual of Geology, proposes the name
Archaean (beginning) as being non-committal. There is no doubt that the
Eozoic was preceded by an Azoic era, but it yet remains for the rocks of either
period to be fully identified.

* Winchell suggests that likely the lowest Azoic rocks in the earth's pave-
ment have melted off as the isogeothermal line has gradually risen through the
thickening of the earth's crust.

t In the Azoic rocks are conglomerates bearing no resemblance to the beds
in which they are found. They are fragments of other rocks, other continents
perhaps, broken up and destroyed. There is, then, little hope of our discover-
ing the origin of life on the globe, since this page of the genesis of the facts has
been torn. For some years geologists loved to rest their eyes in this long night
of ages upon an ideal limit, beyond which plants and animals would cease to
appear. Now, this line of demarcation between the rocks which are without
vestiges of organized beings and those which contain fossils are nearly effaced
among the surrounding ruins. On the horizon of the primitive world we see
vaguely indicated a series of other worlds which have altogether disappeared ;
perhaps it is necessary to resign ourselves to the fact that the dawn of life is lost
In this silent epoch where age succeeds age till they are clothed in the garb of
eternity. The river of creation is like the River Nile, which, as Bossuet says,
hides its head— a figure of speech which time has falsified ; but the endless spec-
ulations opened up by these and similar considerations led Lyell to say: " Here
I am almost prepared to believe in the ancient existence of the Atlantis of
Plato."— M. Esquiros.

$ T. Sterry Hunt classifies the Eozoic rocks into four periods, according to
their lithological peculiarities, viz., Laurentian, Huronian, White Mountain,
and Labrador.

100 HISTORICAL GEOLOGY.

The beds of Lauren tian rocks are about 30,000 feet
thick, and the Huronian from 10,000 to 20,000 feet.

ZtOCalion. — On our continent the Eozoic area com-
prises the surface rock of a V-shaped region resting on

FIG. 41.

The Eozoic Continent.

the great lakes, one arm reaching N.W. to the Arctic
Ocean, and the other N.E. to Labrador; in addition,
there are isolated sections, as shown in the map (Fig. 41).
These constitute, so far as we know, the most ancient
dry land of America — the Canada area representing the
Eozoic continent, and the other portions widely scat-

EOZOIC TIME. 101

tered islands. "Walking along the summit of that
region," says Agassiz, " we may feel that we are treading
upon the granite ridge that first divided the waters into
a Northern and a Southern ocean ; and, if our imagi-
nation carry us so far, we can look down to its base, and
fancy how the sea washed against this earliest shore of a
lifeless world." *

Kinds of 3?oc%.—The rocks are generally crys-
talline or metamorphic, as granite, gneiss, marble, quartz-
ite, limestone, etc. Beds of graphite, porphyry, soap-
stone and slates, also occur. All were doubtless de-
posited as sedimentary strata, and afterward crystallized.
The Eozoic was emphatically the era of iron. The iron-
ore beds of the Adirondacks in northern New York,
the Iron Mountain of Missouri, the Marquette mines
of Lake Superior, and many others, date from this time.

Fossils. — Little is definitely known concerning the
life of this era. The earliest organisms were doubtless
very simple, hence their traces in the rocks would natu-
rally be exceedingly obscure. Fig. 42 represents the
appearance of a bit of fossiliferous marble from the Lau-
rentian rocks. The dark layers are composed of serpen-
tine, and the white of limestone. If the latter be removed
by an acid, the serpentine layers and granules resemble

* "To me it seems, that to look on the first land that was ever lifted above
the waste of waters, to follow the shore where the earliest animals and plants
were created when the thought of God first expressed' itself in organic forms,
to hold in one's hand a bit of stone from an old sea-beach, hardened into rock
thousands of centuries ago, and studded with the beings that once crept upon
Its surface or were stranded there by some retreating wave, is even of deeper
interest to men than the relics of their own race, for these things tell more
directly of the thoughts and creative acts of God." — Agassiz,

10% HISTORICAL GEOLOGY.

the casts of Khizopods.* To this Laurentian fossil, the
relic of the creature that, so far as we now know, first in-
habited the earth, the name of Eozoon
Canadense (Canadian dawn-animal) has
been given.

No vegetable remains have yet been
detected. Still the presence of graphite,
which is so abundant that there is as
much carbon in the Laurentian rocks
as in the same amount of the carbon-

Serpenune^Marble of iferoug) fc almost positive proof of their

former existence. The immense de-
posits of iron-ore are also suggestive of abundant vege-
tation at the time of their formation. f It would seem
reasonable to suppose that vegetable life had the prece-
dence, since the animal kingdom is wholly dependent on
the vegetable for its subsistence ; and thai the first vege-

* These animals are named root-footed because of their root-like feet— fleshy
stems, which they often extemporize upon occasion. (See " Fourteen Weeks in
Zoology," p. 275.) It is proper to say that many celebrated geologists, such as
Morse, Whitney, Burbank and others, still refuse to accept the organic character
of the EozoOn. Mr. Hawes has recently discovered in what are supposed to be
Huronian greenstones of New Hampshire, fossils allied to the Eozoon, the
infiltering mineral occupying the casts of the animal being a silicate. Should,
however, the EozoOn be rejected, the limestone of the Eozoic still suggests,
if it does not prove, the presence of animal life.

t It is thought by many chemists that all iron-ores are of marsh origin. The
growth of the so-called bog-iron is as follows : Iron is contained in the soil in
slight amounts, as a ferric oxide or common iron-rust, which is insoluble in
water. But if there is vegetable matter present in the water, it deoxidizes the
iron, changing it to the soluble ferrous oxide. On exposure to the atmosphere,
the iron takes up the rejected oxygen again and with it water (see " Fourteen
Weeks in Chemistry," p. 154), becoming ferric hydrate. This, being insoluble,
is deposited on the bottom of the pond. One can discover this reddish-brown
sediment of iron-rust accumulating in any swamp. At various points in New
England and elsewhere bog-iron was formerly collected in such abundance as to
be used for manufacturing purposes. The ore gathered so rapidly that the
ponds were dredged every few years.

EOZOIC TIME. 103

tation consisted of land-plants, since the earth would be
cooled sufficiently to admit of life sooner than the water;
and, moreover, plants can exist in hotter waters than is
possible for animals.

. — /. Mountains. — Between Canada and
New York runs a range of hills called the Lauren tian.*
They are probably the oldest mountains upon the con-

tinent.

2 . Upfiearals. — The metamorphism of the Eozoic
rocks was closely attended by extensive upheavals, which
twisted and folded them, throughout vast areas, into
every conceivable form. They commonly remain, how-
ever, in regular layers, which can be traced. This would
indicate a uniform force acting at right angles to the
dip of the beds. These movements must have taken
place prior to the Silurian age, since the Silurian rocks
rest unconformably upon the Eozoic, as is shown in the
accompanying figure. The sedimentary rocks A, lie hori-
zontally upon tilted gneiss, C, and black slate, B. The

* " Their low stature, as compared with that of other more lofty mountain
ranges, is in accordance with an invariable rule, by which the relative age of
mountains may be estimated. (A conclusion first suggested by Hall. See Intro-
duction to Vol. Ill, New York State Reports.) The oldest mountains are the
lowest, while the younger and more recent ones tower above their elders, and
are usually more torn and dislocated also. This is easily understood when we
remember that all mountains and mountain chains are the result of upheavals,
and that the violence of the outbreak must have been in proportion to the
strength of the resistance. When the crust of the earth was so thin that the
heated masses within easily broke through it, they were not thrown to so great
a height, and formed comparatively low elevations, such as the Canadian hills
or the mountains of Bretagne and Wales. But in later times, when young,
vigorous giants, such as the Alps, the Himalayas, or later still, the Rocky
Mountains, forced their way out from their fiery prison-house, the crust of the
earth was much thicker, and fearful indeed must have been the convulsions
which attended their exit."— Geological Sketches, Agassiz.

104 HISTORICAL GEOLOGY.

FIG. 43.

Unconformity of the Lower Silurian with the Gneiss at Montmorency Falls.

Eozoic rocks at Montmorency are about 12,000 feet in
thickness. Through what ages must those vast deposits
have slowly gathered in the primeval ocean !

3. The Outlines of the Continent.—™^ V-

shaped Eozoic land was the nucleus around which the
continent grew. Through the subsequent ages addi-
tions were made to this germ upon the southeast and

EOZOIC TIME. 106

southwest sides. Its very shape was thus a prophecy of
the shape of North America. The direction of the two
arms was parallel to that of the Atlantic and Pacific
oceans (Fig. 41). The land and the sea have from the
beginning maintained these relative positions. In addi-
tion, the location of the scattered areas of primeval rocks
singularly indicated the great mountain ranges yet to
be elevated. We are thus led to believe that the thought
of God, as ultimately revealed in the form of this con-
tinent, was fairly outlined in the first land that appeared.
How accurately did the ancient "backbones" define
the present contour of the finished continent! The St.
Lawrence flows to the sea through a valley parallel to
the Laurentian ridge ; the Mississippi River in a second
valley inclosed between the Appalachian and the Rocky
Mountains; the Mackenzie finds its way to the Arctic
sea in a third valley between the Rocky and the Lau-
rentian mountains ; while Hudson's Bay is snugly locked
in the arms of the Laurentian Mountains.

£. T?ie Mosaic Account informs us that on the
third day the waters were gathered into one place and
the dry land appeared, and that vegetation was brought
forth as a later Creation of the same day. The geologic
record of the Eozoic age agrees with the first portion,
and upon the second gives as yet only hints of possible
discoveries. The direct rays of the sun could not pene-
trate the thick mists which then enshrouded the warm,
damp earth; and hence, although the sun and moon
had shone from the beginning, they were not yet set
in the firmament to rule the day and the night.

106 HISTORICAL GEOLOGY.

Scenic Description. — The varying theories, and
the meagre geological records of the Eozoic Time, give
scanty materials for sketching the scenery of that first
of the world's great aeons. Nature was then lavish
of time,* spending half of all geologic history in work-
ing out the skeleton of a continent and developing an era
of protozoans. The imagination must fill out the picture
from a few outlines. The earth, larger than now. The
waters, protected by a thin crust, still simmering with the
interior heat. The air, heavy with moisture and dense
with carbonic-acid gas. The granite rocks, clothed with
lichens. The shores, strewed with sea- weeds and diatoms ;
and the ocean bottom, covered here and there with masses
of Rhizopods slowly building up their lime-reefs.f

§ALEOZOIC flME.

f 3. Carboniferous Age.
PALEOZOIC TIME. -3 2. Devonian Age.
( i. Silurian Age.

The Paleozoic time is divided into three ages to mark
the great life-changes which occurred. These are called
the Silurian or Age of mollusks, the Devonian or Age
of fishes, and the Carboniferous or Age of coal-plants.

* Since this long beginning, Nature seems to have "been more chary of
the diminishing years. Dana reckons the relative length of the Paleozoic,
Mesozoic, and Cenozoic times as 12, 3, and 1, respectively.

t Read an excellent article on " The Earlier Forms of Life," by Prof. C. H.
Hitchcock, in Popular Science Monthly, January, 1877.

PALEOZOIC TIME. 107

Though unlike in marked particulars, they are yet dis-
tinguished by certain common features in the life they
supported, while they are all very dissimilar to any later
formations. Neither birds nor mammals were known,
and many extensive classes of animals which charac-
terized these ages disappeared with them.

I. SILURIAN AGE.

Oriskany Period.

Lower Helderberg Period.

SILURIAN AGE. I " [" xr ^ ^^

/A ,, ^ \ I i. Niagara Period.

(AGE OF MOLLUSKS,) *. .

r - Hudson Period.

Trenton Period.
Potsdam Period.

This first grand stage in the progress of life on the
globe was so called by Murchison, the celebrated English
geologist, who, having investigated it in Wales, named
it from the ancient Silures, a tribe of Britons formerly
inhabiting that region. The subdivisions of the age
vary greatly in different portions even of the United
States. The Silurian and Devonian rocks are very dis-
tinctly developed in New York, and the epochs estab-
lished in the geologic survey of that State are therefore
accepted, f Fig. 44 is an ideal section extending from

* The Lower Silurian is known by many of the most distinguished American
geologists as the CAMBRIAN. It was so styled by Sedgwick, the contemporary
of Murchison, from Cambria, the Latin name of Wales, where the rocks are
extensively developed. Dana, however, makes the Cambrian only a period
extending through the Potsdam. According to Hall, Scdgwick's original desig-
nation included the Caradoc = Hudson River group of the New York Survey.

t This system has been established by the genius and toil of James Hall,
LL.D., State geologist, and that of his indefatigable assistants. The New York,
nomenclature is accepted by all geologists as the standard for comparison.

108 HISTORICAL GEOLOGY.

the Eozoic rocks in the northeastern part of the State
to the carboniferous in the southern. It will be seen

FIG. 44.

Ideal Section of the New York Formations (Ball).

that the different epochs succeed one another regularly.
The dip of the strata is by no means as uniform as is
represented, nor is there any attempt to indicate their
relative thickness. This illustrates on a grand scale the
fact stated on page 77 concerning the method of geologic
study.

We shall see that, with, each period, a narrow, irregular
'belt was added to the Eozoic area, from which, as a germ,
the continent grew by successive additions.

General Characteristics.—^ is probable that at
this early day the Appalachians on the east and the
Eocky Mountains on the west were great reefs, lifted
above the floor of the sea, thus rendering the interior of
the continent an open sea, protected in some measure
from the ocean. At the bottom of this shallow basin,
sandstone, shale and limestone were formed. The kind
of rock varied in different sections of the country and
periods of the age, according to the peculiar circum-
stances which influenced the deposit of sediment at any
specified place or time. There were broad areas of low
jnud-flats and wave-washed sand-beaches. There may

POTSDAM PERIOD. 109

have been rivers and lakes on the Eozoic continent, but if
so, they have entirely disappeared in the wreck of subse-
quent changes.

The land was rocky and barren, while the waters
swarmed with crustaceans and mollusks.* The pale sun,
struggling to penetrate the dense atmosphere of a yet
heated primitive world, for the first time yielded a dim
imperfect light.

POTSDAM PERIOD.f

Z/ocalion. — This period is named from Potsdam, a
town in northern New York, where the rock is exposed
in the quarries to a thickness of seventy feet. The for-
mation is well developed in Pennsylvania, and can be
traced westward through Michigan, along the southern
shore of Lake Superior, through Wisconsin and Min-
nesota to the Black Hills of Dakota, southward along
the Appalachian range from Vermont to Alabama, and
is known in Texas.

l£ind of ffiocfc. — The rock varies much throughout
this wide extent. At Potsdam it is a coarse, hard sand-
stone; at Malone, a friable one; at Keeseville, a quartzite;
and at other localities, a fine white sand, fit for glass-

* Mollusks are soft -bodied animals usually inhabiting a shell, like an oyster.
The crustaceans are covered with shells, like the crab, but are articulated or
jointed animals.

t Dana locates at the base of the Lower Silurian (Cambrian system) the
ACADIAN EPOCH, which includes the beds of St. John, New Brunswick, and of
Newfoundland. This rock occurs as a slate at St. John and in New Brunswick,
but a compact kind of wacke or quartzite at Braintree near Boston, Mass.
(HaU.) It is characterized by a large Trilobite, the Paradoxides— a genus
anknown afterward.

110

SILURIAN AGE.

making. At some points in the east it is a good building-
stone, smooth solid masses being taken out thirty feet
square and two feet thick; while at the west it is often
so friable as to crumble in the fingers. The colors are
brown, yellowish, etc., often beautifully mottled with red
or gray, and in the west with green. In many localities
it is worm-burrowed,* ripple-marked, mud-cracked, and
rain-pitted, showing the mode of its formation on a low
sand-beach or mud-flat. The upper portion of this
period, known as the Calciferous Epoch,\ is in part a
magnesian limestone, so that some layers are even burned
for lime. The fissures and geodes are often lined with
quartz crystals as in Herkimer county, N. Y. In the
Mississippi valley its character changes, the silica de-
creases, and it is called the Lower Magnesian Limestone.

FIG. 45.

Fossils. — A brachiopod, the
lingula (little tongue), so named
from its peculiar shape, is a char-
acteristic fossil. In form and
size the shell is similar to the
finger-nail. The peculiarity of
this mollusk was that it grew
on a fleshy stem which anchored
it to the rock. Several species
of the lingula still exist in the
Moluccas. A crustacean, the trilobite (three-lobed), is

* The holes burrowed out by marine worms were filled with sand, which
hardened like the rock itself, and, when the rock is broken, forms regular casts
of the worm -burrow.

t Logan groups the Calciferous Epoch, the Leyis shales and sandstones so
abundant near Quebec, and the Chazy limestone (p. 115), into a new period, the
CANADIAN. It is probably the equivalent of a part of Emmons's Taconic
system, which occurs as a slate rock in New York east of the Hudson, as at the
outcrop near Poughkeepsie.

antiqua.

POTSDAM PERIOD.

Ill

FIG. 46.

the most conspicuous fossil. This family was promi-
nent in the early creations, but disappeared in the
Carboniferous Age. It is perfectly
preserved, and the various stages
of growth, from the egg to the
adult, have been more accurately
traced than even those of the
crab, a living crustacean. It was
of wonderful variety, more than
400 species having been discov-
ered. It had an oval figure, and
was from % of an inch to 20 inches
in length. The body, divided into
three lobes,* was covered with a
jointed crust which folded over as in the tail of a
lobster. Some species could roll themselves up into a
ball, and thus present a hard armor in every direction.
The head was protected by a buckler of a crescent form.
The eyes were conical shaped, and each one was com-
posed of many separate facets or lenses, f by means of
which the animal could see in every direction at once.

The inner side of each eye being of no practical value,
Nature, on her principle of economy, placed no lenses
there. The trilobite is supposed to have gathered in
shoals in the shallow water, swimming slowly on its back
by means of membranous appendages now lost.

A Trilobite (Dicellocepha-
lus Minnesotensis.)

* The head-shield is named the bucJder, and the tail-shield, the pygidium.
The former is divided longitudinally into the glabella or middle part, and the
two cheek or side portions.

t Walcott gives the number in a specimen of Batnyurus as 4,720, and in
another of Asaphus, 7,536. A beetle (genus Mordella) of the present time has
25,008 of these facets ; a butterfly (genus Papilio) has 17,355 ; a house-fly, 4,000,
and an ant. 50.

112

SILURIAN A GU.

1, 2. Eyes of Trilobites. 3. Enlarged Lens.

*— /. The Atmosphere '.—The eyes of
the trilobite would have been useless unless the atmos-
phere had been clear enough to permit sufficient sunlight
to reach the earth to render objects visible in some de-
gree. God makes all things for a purpose; hence we
conclude that at this early period the sun had pierced
the clouds, and the air was being purified.

2. fiarty Silurian Beach.— Where the Pots-
dam rock lies on the surface, we are assured that that
locality was raised above the sea at or near the close of
this period (unless uncovered by subsequent denudation),
else it would have been concealed by the sediment of the
succeeding one. The narrow zone of the Potsdam rock
along the borders of the Eozoic area, was doubtless the
beach of the early Silurian sea.

3 '. Ztife.-r- The organic remains found in this period
are principally crustaceans (Hall), though the Protozoans,
Badiates,* Mollusks, and Articulates are represented
among animals, and the sea-weeds among plants. The

* For the sake of simplicity the two sub-kingdoms, Echinodermata and
Ccelenterata are here combined in the name Radiates (see Zoology, p. 13).
They are BO called because they have a radiated structure, as the star-fish.

POTSDAM PERIOD. 118

trilobite was the highest type. All the sub-kingdoms of
invertebrates were thus represented ; but vertebrates had
not yet appeared. No signs of land vegetation have been
found. The dry Eozoic hills may have been covered with
lichens, but they bore no moss or grass, the sea contained
no fish, and the air no bird.

^. Climate. — No difference is seen in the life of
different latitudes; hence it is thought that there was a
uniformity of temperature existing over the earth, and
that the diversity of zone and climate had not yet been
established. Various reasons have been assigned for this,
among which are — (1) the greater heat from the inte-
rior on account of the thinness of the crust, (2) the
dense atmosphere which retained the sun's heat more
fully, (3) the great expanse of the ocean which tended to
equalize the temperature, and (4) the greater size and
heat of the sun in that era, according to the nebular
hypothesis.

5. Changes in the Sea, Z,ife, and

Shales were produced in the muddy water, and lime-
stones in the shallow, clearer sea — since the coral animal
thrives best in pure water less than a hundred feet deep.
The crust of the still unsteady earth, as it rose and
fell, shallowing or deepening the waters, rendering them
muddier or purer, varied the character of the life sup-
ported and the rock formed.

6. £afce Stiperior.—Vo\e,%mc convulsions in that
region having tilted the rocks, a depression of the crust
was produced, thus forming the bed of Lake Superior.

114 SILURIAN AGE.

In this connection there were igneous ejections, making
trap-rocks and dikes. The fissures were also filled with
native copper and silver, among the richest deposits in
the world. The sandstone has since been worn into
grotesque and curious forms as seen in the famous
Sculptured and Pillared Eocks. *

7. 2 'he Mosaic Account tells us that the sun and

FIG. 48.

Sculptured Rocks, Lake Superior. " Inverted Volcano.'

* These strata form a wall 50 to 100 feet high, and line the shore for a distance
of five miles. Their marked hues and fantastic shapes excite the imagination
of every beholder. Here is " Miner's Castle," with its turrets and bastions ;
there " Sail Rock," a ship with sails full spread ; and yonder " The Amphi-
theatre," with its symmetrical curves. A closer inspection only reveals more
curious details and resemblances. For a very interesting account of these
rocks see Harpers' Magazine, Vol. XXXIV, p. 681,

T&ENTON PERIOD. 115

moon were created on the fourth day. Geology shows
us that the distinctive feature of the early Silurian
Age was the partial clearing of the sky after the murky
clouds of the Eozoic. The first glimpse of the sun would
have seemed to an observer as a new creation, and, in
popular language, it is thus described in Genesis, We
also read that on the fifth day the waters brought forth
abundantly the moving creature that hath life. We shall
see how perfectly the swarming seas of the Silurian and
Devonian Ages justify this description.

TRENTON PERIOD.

.Location. — The Trenton formation extends along
the great Appalachian chain of mountains on the east,
thence outcrops at various points westward to the Missis-
sippi River, and beyond the Rocky Mountains. It is
more widely distributed than any similar deposit.

IC'inds of ffiocfc. — This was the first great limestone
period of the continent. In New York there are four
epochs— (1) the Chazy limestone,* (Shaz-ee), named from
a locality near Lake Champlain, which is the passage rock
from the Calciferous sandstone ; (2) the Bird's Eye lime-
stone, a dove-colored rock containing white crystalline
points scattered through it; (3) the Black River lime-
stone, a black, hard-grained marble, f named from the river

* In Wisconsin, Iowa, Minnesota, and Illinois, the equivalent of the Chazy
if* the St. Peter's sandstone, — a soft, white, incoherent rock, composed of grains
of quartz that crumble easily under the hammer, though in some localities it
is hardened by a calcareous cement. It is used in Chicago for glass-making.
Like the Lower Magnesian Limestone, it is destitute of fossils.— Whitney.

t At Watertown. N. Y., it is lumpy, and breaks into rhomboidal fragments,
while the Bird's Eye has a conchoidal fracture. The river is said by some to
take its name from the dark color of the rocks over which it flows.

116

S1L URIAN A GE.

of that name, east of Lake Ontario ; (4) the Trenton lime-
stone* a hard, compact rock, black in the lower beds and
gray in the upper, so called from the well-known gorge
at Trenton Falls. In Wisconsin, Iowa, etc., the Galena
limestone is an upper member of the group not known
at the east. It is the great lead and zinc bearing rock
of a region embracing about .3,000 square miles. The
streams have cut deeply down into this formation, so
that they are bordered by precipitous bluffs crowned
by perpendicular ledges, having frequently a castellated
appearance like the walls of some half-ruined city, while

FIG. 49.

Maclurea Magna.

* The massive pillars of the court-house at St. Louis are from the Trenton
limestone quarries of Sulphur Spring. The crest of the Falls of St. Anthony is
of Trenton limestone. The beautifully variegated marbles of Tennessee are
also of this period.

TRENTON PERIOD.

117

isolated masses sometimes rise abruptly from the valleys
like lofty watch-towers.

FIG. 50.

FIG. 51.

Bird's Eye Fucoid (Phytopsis tubulosum).

Fossils. — A peculiar coiled shell (Fig. 49) is abun-
dant in the Chazy.* Fig. 50 represents a characteristic

marine plant found in the
Bird's Eye limestone. The
ends of the stems give the
rock the dotted appearance
from which it takes its
name. Fig. 51 is a coral
common in the Black Kiver
limestone. It has been
found in masses of a ton's
weight. The Trenton lime^

Black River Coral (Columnaria
alveolata).

* Like all Gasteropods (see Zoology, p. 244), the common snail for example,
It moved upon a fleshy disk or foot heneath the body. The layers of Chazy
limestone, when worked as a marble, often show upon a dark gray surface the
white spirals of this shell.

118 SILURIAN AGE.

stone abounds in organic remains. Corals, crinoids, and
shells are crowded together in the greatest profusion.
Thin, semi-transparent slices, apparently devoid of fossils,
under the microscope reveal their animal origin.

Brachiopods * occur in wonderful variety. Trilobites,
•the highest type of the Potsdam, appear of a dozen
species, varying in size from that of a finger-nail to a
foot in length. They, however, yield in abundance,
activity and power to the cephalopods.f A family of
these, the Orthoceratite (straight-horn), distinguishes the
entire period. It had a long straight shell, divided into
sometimes as many as seventy chambers. These were
formed to accommodate the growth of the animal. As
it increased in size, it moved forward in its room, and
extending its shell at the larger end, partitioned off its
new quarters from the rest by a shelly wall. Thus, in
time, a long series of chambers was made, each larger
than its predecessor. J They were connected, however,

* The Brachiopods (arm-footed) are bivalves having arms by which they stir
the water, and thus bring their food within their reach. The two parts of the
shell are unequal ; the larger is called the ventral and the smaller the dorsal
valve. Each valve is, however, equal sided, so that if a line be dropped from
the beak to the opposite side, it will divide the valve into equal parts.

| The Cephalopod (head-footed) is also a Mollusk, something like the Cuttle-
fish of to-day (see Zoology, p. 243), having arms arranged around the head.
% " Year after year beheld the silent toil
That spread his lustrous coil ;
Still as the spiral grew,
He left the past year's dwelling for the new.
Stole with soft step its shining archway through,

Built up its idle door,

Stretched in his last-found home, and knew the old no more.
•* Thanks for the heavenly message brought by thee,
Child of the wandering sea,
Cast from her lap forlorn.
Cast from thy dead lips, a clearer note is bora
Than ever Triton blew from wreathed horn ;

While on my ear it rings,
Through the deep caves of thought, I hear a voice that sings:

TRILOBITES OF TRENTON PERIOD.

Orthoceras multfcameratum (Black River

SILURIAN AGE.

by a membranous tube (" siphuncle "), which passed from
the animal in the newest and largest chamber at one
end to the oldest and smallest room at the other. These
empty chambers are thought to have acted as a buoy to
float the heavy animal. Some of the fossil orthoceratites
are not larger than a lead pencil, while others are a foot
thick and thirty feet in length. They had many mus-
cular arms, with which they seized and strangled their
prey in their powerful grasp. They were doubtless the
sea-rovers of the Lower Silurian Ocean.

H U DSON PERIO D.

ZfOCation . — This formation is exposed to view along
the Hudson and Mohawk rivers, on 7 '-.? Michigan aad
Green Bay, through the Mississippi va. aixd ^-ng the
Appalachian range to Alabama.

J&nds of ffiocfc.—Io. New York there are three
epochs —

(1) The Utica slate, a fissile, black stone, the surface
rock of the Mohawk valley; (2) the Herkimer shales, and
(3) the Loraine shales, and the Salmon River shales and
sandstones.*

" ' Build thee more stately mansions, oh, my soul,
As the swift seasons roll !
Leave thy low-vaulted past !
Let each new temple, nobler than the last,
Shut thee from heaven with a dome more vast

Till thou at length art free ;

Leaving thine outgrown shell by life's unresting sea.' "

* A fourth may hereafter be recognized as terminating the period ; viz., the
Gray sandstones of Oswego county, which may be the equivalent of the Sha-
wangunk Grit. In the Hudson valley, the New York geologists are not able
clearly to distinguish these members, owing to the contortion of the strata.
At some points the Utica slate appears on the surface, owing to folding of th«
beds (Hall).

HUDSON PERIOD. 121

This period includes an enormous series of shalesa
slate and sandstone, reaching a thickness of perhaps
1,000 feet. The color is dark and bitumen is often
present so as to afford a black pigment. There are thin
seams of a shiny slate which have many times tantalized
those ignorant of geology with unfounded hopes of the
discovery of profitable beds of coal.

At the west the rock becomes a soft calcareous shale
interlaminated with limestone. The group is there
known as the CINCINNATI PERIOD.

Fossils. — In the limestone regions corals, shells, tri-
lobites, etc., are abundant as in the Trenton Period. In
the shales, however, they are sparingly distributed, being
mostly those which flourish in muddy waters. The
graptolites (rock-writing) of the kingdom of Radiates
are striking fossils (see Fig. 53). They are found in the

FIG. 53.

A. Graptolite with Eight Arms (Graptolithus octobrachiatus), Quebec Group.

(Hall.)

Potsdam, but become very plentiful in the Hudson
Period. They are merely a delicate, plume-like tracery
upon the rock. They have therefore been poetically

styled sea-pens. They delighted in foul, as the corals in
clear water, and must have thickly covered the muddy
bottom of the shallow sea with their fragile, mossy
branches. They are commonly found in scattered frag-
ments, the arms only of the entire animal as seen in
Fig. 53.

Changes.— Life and death
were coeval from the first — one species giving place to
another, most commonly at the close of a period, but
frequently within its duration. Some catastrophe oc-
curred, for example, at the close of the Chazy Epoch
which destroyed nearly all the species then existing, and
the Trenton Epoch was therefore characterized by new
species. It was still, however, the reign of mollusks,
since that subkingdom was exhibited in its various
classes, while the articulates had not progressed above
the crustaceans and worms, and no vertebrates have yet
been discovered. Another marked change took place at
the close of the Lower Silurian. The Green Mountains
were upturned and metamorphosed, thus closing the
making of rocks in that region,* while a vast section
extending from Lake Erie to Tennessee was raised above
the ocean so as to form a great island in the Upper
Silurian Sea. The land, so far as geology teaches,
remained leafless and lifeless as at the beginning. The
sea, however, in its shallower places, resembled a flower-
garden, with its abundant corals.

* According to Hall, however, there are Devonian limestones at Lake Mem-
phremagog and at Bernardstown in Massachusetts, and Lower Helderberg in
Maine.

NIAGARA PERIOD.

2. Geograpfi/y . — Lake Champlain probably dates
from this time. The continent was steadily pushing its
way southward and had reached the central part of New
York. 'Western New England had emerged from the
sea, while the then low, narrow Kocky Mountains repre-
sented the western part of the continent.

NIAGARA PERIOD.

. — This is a continental formation like the
Trenton. It is found in Canada, and extends south
through the Appalachian region, and west through the
M-ississippi valley. It takes its name from the fact that
the great cataract of Niagara pours over a rocky wall
of this period. The peculiar form of the fall is owing
to the fact that the soft shale below wears away more
rapidly than the hard rock above, thus leaving a cavern
behind the falling sheet.

J£inds of ffiocfc. — In New York there are four
epochs. (1.) The Oneida Conglomerate,* called from a
county of that name in central New York, is a gritty,
hard conglomerate, so rough as to form millstones.
From its abundance in the Shawangunk Mountains it
is locally known as the Shawangunk grit. (2.) The
Medina sandstone, named from the locality in western
New York where the rock is extensively quarried for
building purposes, is a thickly laminated sandstone, of
red, gray, and beautifully mottled colors. (3.) The Clin-

* Hall inclines to refer this conglomerate to the Hudson Period as a fourth
member. (See note p. 120.) It is clearly a passage rock.

1%4 SILURIAN AGE.

ton Group, so called from a village in central New York,
is generally a shale or sandstone,* and always contains
beds of limestone. (4.) The Niagara proper consists of
a shale and a limestone of a light gray or cream color and
of an enduring hardness, but yet soft enough to be easily
wrought in any desired form. The so-called "Athens
marble " of Illinois, is almost a pure dolomite. Around
Chicago the stone is often saturated with mineral oil,
At Lockport, New York, dog-tooth and pearl-spar, also
gypsum and other minerals, are found in beautiful crys-
tals lining the cavities in the rock. At the west the
Niagara limestone stands in bold bluffs along the rivei
banks. It contains nodules of hornstone (" chert "), often
arranged in layers parallel to the strata. The Niagara
rock is frequently found capping small hills or knobs, and
has hence received the name " Mound limestone."t

lK the Clinton beds a brachiopod (the
pentamerus, five-parted) is very abundant. Sea-weeds
(fucoids) cover the Medina sandstone in many places.
with their interlacing stems, curiously wrought, like the
intricate carving of some old Gothic cornice. The
Niagara rocks abound in corals, crinoids, shells, etc.
They are doubtless the remains of old coral reefs.

* In Michigan and some of the western States it assumes still more of a lime
stone character, and in New York, Ohio, and Wisconsin, has beds of o61itic iron
ore of great value. In Tennessee it is called u dye-stone," being extensively
used for dyeing cloth.

t The Blue Mounds, Platte Mounds, Sinsinnewa Mound, in Wisconsin;
Sberald's, in Iowa ; Scales's, Charles's, Waddell's, Pilot's Knob, etc., in Illinois ;
are striking examples of this peculiarity, since they form conspicuous landmarks
in the scenery of those States. These outliers of the Niagara limestone assume
a great variety of forms, but are always graceful in their outlines, and, as they
are generally covered with forest trees, present a striking contrast to the rocky
bluffs of the Galena limestone.

NIAGARA PERIOD. 125

The crinoids appeared in preceding periods, but now
become \*ery plentiful. They grew on a stem, and had

FIG. 55.

Medina Fucoid (Arthrophycus Harlani).— (Hall.)

somewhat the form of a lily, hence have received the
name of "stone lilies." Their cup-shaped body sent out,
star-like, five or more arms ; these branched sometimes
into as many as a thousand, each composed of a hundred
little bones, firmly and exquisitely jointed together. The
stalk was also jointed, like the vertebras of the spine, and
was curiously grooved and ornamented on the surface.
The arms were adapted to be spread out, and lined with
tentacles to seize and draw into the centre shoals of
animals, the food of the crinoid. Their forms were of
varied patterns, and their markings exquisitely beautiful.
(See Zoology, pp. 263, 264.) In many places the rock is
a confused mass of crinoidal stems (Figs. 58 and 75),
which, when polished, present a curiously attractive ap-
pearance.

NIAGARA CRINOIDS.

FIG. 57

Eucalyptocrinus decorus.

"Lecanocrinus macropetalus,

SALINA PERIOD.
FIG. 56.

207

A Niagara Coral (Hall).

SALINA PERIOD.

Location. — This period is named from the Salina
salt springs near Syracuse, N. Y. The formation runs in
a narrow belt parallel with the Niagara limestone, as far
westward as Milwaukee.

FIG. 58.

Encrinital Limestone, Niagara Period (Hall).

Kinds offfoc&.—The rocks consist mainly of shales,
marls, and some limestone. The saliferous beds are about

1%8 SILURIAN AGE.

1,000 feet in thickness, showing a long continuance of the
peculiar conditions under which they were formed.

Fossils. — There are few organic remains. The salt
water seems to have been unfavorable for the existence
of animal life.

.— The Salt Springs of Syracuse have been
accounted for in the following manner: Central New
York was at that time a great salt lake, shut off mainly
from the sea. By continued evaporation, by fresh over-
flows of the brine from the ocean, and by washings of
rains and streams from the adjacent land, muddy deposits
were formed, thoroughly impregnated with salt.*

LOWER HELDERBERG PERIOD.

Location. — This period takes its name from the
Helderbeig Mountains, near Albany, N. Y. The rocks
gradually disappear in the western part of the State, but
are conspicuous southward along the Appalachian range,
and reappear in Maine.

Kind of ffiocfc. — This is also a great limestone
formation, but differs from the Trenton and Niagara
groups in being thickest on the eastern border. The
lower beds in New York and Virginia are used for hy-
draulic cement, whence their ' name— the " Water-lime
group.1'

* Read Winchell's " Sketches of Creation," Chap. XXVI, on Rock Salt an<3
Gypsum.

LOWER HELDERBERG PERIOD.

129

fossils. — The conditions of life seern to have been
eminently favorable. About four hundred species of ani-
mals have been discovered. A brachiopod (Pentamerus
galeatus) is so common in some sections as to give its
name to the rock. A peculiar crustacean, the eurypterus
(broad-fin), is allied to the trilobite. Crab-like in its
organs of mastication, lobster-like in its prolonged and
segmented body, with its broad swimming-limbs and

FIG. 59.

FIG. 60.

Pentamerus galeatus (Vanuxem).

Eurypterus remipes.

huge claws, it presents new and striking
FIG. 61. features. Some species seem to have
been six or eight feet in length. They
were the scavengers of their time, living
on the lower forms and garbage by the
sea-shore. Small cones, called Tentacu-

(Hall). ^^^ are g

compose the mass of the rock.

.— Geography. — The formation of lime-
stone during this period in eastern New York and in

190 SILURIAN AGE.

the Green Mountain region shows that these sections
must have been depressed, and the mountains, in part
at least, again submerged in the sea. More than half of
New York, nearly all of Canada and Wisconsin, had now
become dry land. A great bay, however, covered a large
part of Michigan. The rivers were probably small, and
fresh water lakes, if any existed, have disappeared.

ORISKANY PERIOD.*

Z<ocalion . — This formation is named from Oriskany
Falls. It crops out at points in Maine, extends south-
ward along the Appalachian region, and westward to
Missouri. It is the passage-rock from the Silurian to
the Devonian.

l£ind of ffiocfc. — It is mostly a light, rough sand-
stone, often highly calcareous. Its thickness in New
York varies from twenty feet at the typical locality to
only a few inches toward the Hudson ; in Pennsylvania
it is 200 feet thick. Its color is white, passing to a
reddish-brown where iron is present.

. — The most common fossil is a brachiopod
(Fig. 62). The rock is often made up of these character-
istic shells or of their casts. The latter are represented
in Fig. 63. It is a mould of the interior of the shell
formed by the sand which filled it, while the substance
of the shell itself has decomposed.

* In Southern Illinois there is a formation termed the Clear Creek limestone,
which seems to mark a transition from the Silurian to the Devonian, since it
contains \Arell-marked fossils of both ages. It forms the Mississippi Bluffs south
of Thebes.

OR1SKANY PERIOD.

131

.— /. This formation is another feature of

the old Appala-
chian sea-beach.
The thickness of
the rock, as it ex-
tends southward
from the Eozoic
area,* indicates a
deepening of the
water which cov-
ered both New
York and New
England, while
the Green Moun-
tains were a nar-
row island sepa-
rating them.

2. Climate.

— The fossils, con-
stituting a kind of
life - thermometer,
indicate that the
climate of the Si-
lurian was uni-
form.

'Progress
.— The

FIG. 62.

Spirifer arenosus (Vanuxem).

FIG. 63.

A Cast (Vanuxem).

* The material for making the continent came always from the north-east.
For this reason formations are generally coarser east, and finer west. Shales
and sandstones east often become limestones west.

1S% S1LVR1AN AGE.

grand types of life remained. Continued changes, how-
ever, took place in the development of the creative idea
by the disappearance* of old genera and the appearance
of new ones. Mollusks continued to take the lead, while
the articulates were as yet represented only by the second
class — crustaceans. Neither plant nor animal was seen
on the land, and no fish sported in the waters.

£. Uniformity of Nature. — The construction of
the eyes of the trilobite shows that the laws of light were
the same then as now. The animal itself was very like
the king-crab of the Atlantic coast. The orthoceratites
were the progenitors of the nautilus, the shell being un-
coiled in those early species. The sea-shore was clad in
weeds, and in favorable localities the waters were thronged
with inhabitants. Species and genera took their places
in the grand subkingdoms of animal life It requires no
great stretch of the fancy to people those early seas, and
imagine the inhabitants busy and joyous on a summer's
eve as the tribes that throng our existing oceans.

Scenic Description. — Let us picture to ourselves
the scenery of the Silurian Age. The air, damp with
fogs and foul with noxious gases, hangs heavy over land
and sea. The sun sheds a strange, lurid glare. The land,
faintly visible in the dim light, presents few attractions.
The new-born continent is yet crude and unfinished.
Vapor is rising in clouds from the heated surface. With

* For example, the chain-corals and graptolites passed away with the Upper
Silurian, while the crinoids greatly increased. Dana says that not one species
belonging to the latter part of the Lower Silurian existed at the close of the
Upper Silurian.

SCENIC DESCRIPTION. 133

no song of bird, no hum of insect, no garment of ver-
dure, it is a broad, low, barren, rocky desert. Everywhere
are seams, and gnlfs, and ridges, rent and upheaved by
earthquake shocks, and swept by volcanic floods. The
sea is the only centre of life. The low rocky beach is
garnished with innumerable sea-weeds, whose long trail-
ing branches rise and fall with the tide, while every wave
strews the sand with shells and broken corals, heaped in
lengthened rows like the grass from the mower's scythe.
Trilobites, in swarming shoals, scull their tiny boats in
animated pursuit of food. Huge orthoceratites lie quietly
floating their many-chambered shells on the surface, or
speed through the water with long arms spread to grasp
their prey. The sea-bottom is gay with the lily-shaped
crinoids that, blossoming with life, foreshadow the flowers
which are yet to deck the barren earth. Coral reefs
stretch away in lines of beauty, where myriad workers toil
to build their fragile many-colored homes. In shallower
places, too, there is somewhat of grace, for the graptolites
cover the muddy bottom with their quaint mossy
branches, overshadowing mollusks that sluggishly luxuri-
ate in endless profusion below. Yet as the long age goes
by, continued changes take place. The land rises and
falls. The sea retires, and anon pours swelling in again.
The scene of life shifts from one locality to another.
The great drama of life and death has begun, which is to
be played while the earth endures.

184

THE DEVONIAN AGE.
FIG. 62.

Fishes of Devonian Sea. i. Coccosteus. 2. Pterichthys. 3. Cephalaspis. 4. Holop-
tychius. 5. Osteolepis.

DtiVO NlA N A G E. 135

II. DEVONIAN AGE.

{4. Catskill Period.
^. Chemun£ Period.
2. Hamilton Period,
i. Upper Helderberg Period.

This second great stage in the progress of life on the
earth takes its name from the county of Devon, England,
where the formation is very clearly and extensively de-
veloped. It is often styled the OLD BED SANDSTONE,
from the prevalent color of the rock, and has been im-
mortalized by Hugh Miller under that name. On this
continent its color and character are very different,
although it is similar in its dominant fossils.

General Characteristics. — The continent is still
small, low, and rocky. The Silurian sea is gradually
retiring southward, as period after period adds its belt to
the growing margin of the land. The earth, however, is
no longer lifeless. Flags and rushes abound by the
water-courses, while ferns of rare beauty and plants very
like our rushes, nourish in the marshes. There are cone-
bearing trees, but no conspicuous flowering tree or shrub
like the maple or rose. The graptolites have become
extinct, while that curious crustacean, the eurypterus,
appears in profusion in Europe, but rarely in America.

The marked feature is the fishes which swarm in the
seas.* They were nearly all Ganoids, i. e., they had beau-

* Anderson says the remains of these Ganoid fishes are so ahundant in the
yellow sandstone deposit of Dura Den, Scotland, that a space of little more than

IBS DEVONIAN AGE.

tifully enameled scales encasing them as with an armor,
and often a bony helmet large enough to cover the skull
of an elephant, strong enough to resist a musket-ball, and
hard enough to strike fire like a flint. The tail was
nearly always of unequal lobes, instead of equal lobes or
rounded forms, as at the present. Thus, says Agassiz,

FIG. 64.

i. Heterocercal, or unequally bilobate ; 2. Equally bilobate ; and, 3. Single and
rounded form of tail.

the progress of life through the ages has been marked in
the tails of the fishes. Among the most peculiar of these
fishes we notice — 1. THE COCCOSTEUS (berry-bone),
which takes its name from the tiny berry-like projections
ornamenting its plated armor. Its teeth are chiseled, as
it were, out of the solid jaw, just as the teeth of a saw are
cut out of the solid metal. 2. THE PTEKICHTHYS (wing-
fish) had two arms or wings, combining the broad blade
of a paddle with the sharp point of a spear, which served
both for propulsion and for offence. The head was cov-
ered with a strong helmet, perforated in front by two
circular holes, through which the eyes looked out. Its
chest was protected by a curiously constructed cuirass
formed of plates, and the tail was sheathed in a flexible

three square yards yielded above 1,000 fishes, most of them perfect in their out-
line, with scales and fins quite entire, and the forms of the creatures often start-
ing freely out of their hard, stony matrix into their complete armature of scale,
fin and bone.

OF DEVONIAN AGE. 1S7

mail of bony scales. 3. THE CEPHALASPIS (buckler-
head) had a head-plate of a single bone of a crescent
shape. 4. THE HOLOPTYCHIUS (all-wrinkled) is so called
from the curiously wrinkled sculpturing that adorned its
scales. 4. THE OSTEOLEPIS (bony-scale) had bony scales
placed alongside one another like the bricks in a build-
ing, thus affording protection, and at the same time
yielding readily to the bending of the body.

In these fishes there is a singular union of reptilian
and fishy traits. The structure of their skull resembled
that in reptiles, while their air-bladders had a lung-like
character. They could move the head upon the neck
independently of the body. Like reptiles, also, their ver-
tebrae were connected by ball-and-socket joints instead of
inverted cones, as in common fishes.

Comprehensive Types. — The Creative purpose
seems at the beginning to have been sketched in broad,
general characters, and to have included in the first ex-
pression of the plan all the structural possibilities. This
combination of higher with lower features in the early
organic forms is a very striking peculiarity, and becomes
still more significant when we notice that many of the
later types recall the more ancient ones. The latter may
be styled prophetic and the former retrospective types,
since the one anticipates the future and the other recalls
the past. The crinoids, with closed cups in some, and
open, star-like forms in others, united features of the
present star-fishes and sea-urchins, and by their stems,
which fastened them to the ground, included also a polyp-
like character. The armor-plated pterichthys propelled
itself with paddle-arms, like the ' turtle, instead of with

188 DEVONIAN A&E.

the tail, like other fishes. The trilobites, with their uni-
form rings and head-shield, partook at once of worm and
crustacean types. The chambered shells of the ortho-
ceratite and goniatite gave hints of the ammonite of a
later age.

The early fishes prophesied not only the reptiles which
were to come, but also the birds and even mammals.
Though the ancient types have become obsolete, and have
been replaced by modern ones, as Agassiz happily re-
marks, a few old-fashioned individuals have been left
behind to give, as it were, the key to the history of the
race. The gar-pike explains the ancient Devonian fishes ;
the Millepore coral, the old Silurian corals ; the nautilus,
the ammonite and orthoceratite. The thought of God
thus includes all that have gone before as well as all that
now exist. The study of nature reveals to us the present
linked with the past, which is not lost and dead, but per-
petually revivified and reproduced in the life of to-day.

UPPER HELDERBERG OR CORNIFEROUS
PERIOD.

ZfOcalion. — The lower group is found in eastern
New York, and is thickest along the Appalachians ; the
upper group is a great continental limestone like the
Trenton and the Niagara. At the west, in the absence
of the Oriskany, the Corniferous often lies directly upon
the Niagara limestone, except where the Salina rocks
intervene.

Kinds of 3?oc£.—T}\is formation in New York
comprises two epochs: (1). The Cauda-Galli and Scliolm-
rie Grits, which are named, the former — the passage-rock

HAMILTON PERIOD. 189

from the Silurian to the Devonian — from a peculiar
feathery sea-weed common in it, and the latter from the
typical locality in eastern New York. (2). The Hel-
derberg Limestones, — the last great limestone formation
in New York — the lower beds of which are termed the
Onondaga, and the upper the Corniferous limestone.

The Helderberg beds lose their distinctive features
westward and blend into one group, which is called by
either of these names. The Corniferous limestone (cornu,
a horn) derives its appellation from disseminated nodules
of hornstone ("chert"). The Onondaga is a dark-gray
rock which takes an excellent polish. These limestones
are quarried for a building-stone at multitudes of points
throughout western New York, Ohio, Michigan, Indiana,
and Illinois.

Fossils. — This was the great Paleozoic coral reef.
Corals are found in every conceivable form — standing,
lying down, broken into fragments, or preserved as per-
fectly as if they had grown but yesterday. They flour-
ished luxuriantly and may have exhibited all the wealth
of coloring now manifested in the tropical seas. They
are especially abundant at the Falls of the Ohio, near
Louisville. Some have a diameter of five or six feet.
Crinoids and mollusks, in all their orders, present a be-
wildering variety and profusion.

HAMILTON PERIOD.

ZtOcatton. — This formation extends across New
York, Michigan, thence west of the Mississippi river, and
southward through Pennsylvania, Virginia, and Ten-
nessee.

140 DEVONIAN AGE.

J£inds of ftocfc.— In New York this period com-
prises three epochs.*

(1). The Marcellus Shale is a fissile slate, often nearly
jet-black. It abounds in septaria resembling turtles
(see p. 83). It contains so much carbonaceous matter
as sometimes to burn quite freely. This fact has led
to much waste of money in exploring it for coal. The
attempts are always futile, since the formation lies
thousands of feet below the coal measures. (2). The
Hamilton Group f consists of a harder and lighter shaly
sandstone, often calcareous. The layers are remarkable
for the abundance of ripple-marks. They present also a
?ery perfect jointed structure, some fine examples of
which are seen on Cayuga Lake (Fig. 25). (3). The

* The Hamilton series in New York makes one enormous formation. It is
nearly destitute of lime, and thus differs widely from the Onondaga, Trenton,
and Niagara limestones which overlie it on the north. The most marked
physical features of this great extent of country consist in its deep valleys and
long ridgy hills, usually extending in a north-and-south direction, as an inspec-
tion on any map of the rivers which follow the valleys will show. Some of these
long north-and-south valleys, having been excavated so deeply below their
outlets as to retain the accumulated waters of the rains and streams, form that
remarkable series of lakes beginning with the Otsego, and comprising the
Canaseraga, Cazenovia, Otisco, Skaneateles, Owasco, Cayuga, Seneca, Crooked,
•Canandaigua, Honeoye, Canadice, Hemlock, and Conesus lakes ; all so similar in
their general form and direction, and in the shape and geological formation of
their inclosing hills. Over the whole extent of these rocks, the country is "roll-
ing " or broken into ridges generally running north and south, and rising from
one to eight hundred feet above their main dividing valleys ; and it is rarely that
we find among them a plain half a mile in width, excepting in a few of the " bot-
tom-flats " or alluvial lands along the larger rivers. (Lincklaen in Guide to N. Y.
State Cabinet.)

The upper part of Hamilton Group in New York is a dark, impure rock, termed
the Tully limestone. It is about twenty feet in thickness, and contains a few dis-
tinguishing fossils.

t The absence of the Marcellus Group at the west, drops the Hamilton directly
upon the Corniferous, forming the appearance of a single mass. Thus, four
limestone formations— the Niagara, Salina, Corniferous, and Hamilton— are there
brought into juxtaposition. Before they were closely distinguished, the entire
mass was known as the " Cliff limestone," because they often formed bold bluffg
along the river-banks.

HAMILTON PERIOD.

141

Genesee Slate which overlies the Hamilton beds derives
its name from the gorge in the Genesee river, where it is
well developed. It is a dark bituminous shale, rich in
oil. Through the Mississippi valley it is known as the
Black Shale.

Fossils. — The Marcellus Shale contains the orthocer-

atite and goniatite. The
latter is like the former,
but is partly coiled, thus re-
sembling the modern nau-
tilus. The name (gonia,
an angle), refers to the
sinuous form of the parti-
tions which separate the
different chambers. The
Hamilton Group, in its lime-

FIG. 65.

Goniatite (Vanuxem*).

FIG. 66.

stone layers, has fine cri-
noids and corals, but the
predominant fossils are
brachiopods and conch-
ifers, * — species which
nourish in muddy wa-
ters. Among the former

Spirifer mucronatus (Hall).

* Conchifers (shell-bearers) have their gills in thin membranous plates on
each side, as seen in the oyster, whence they are often called Lamellibranchs
(Lamella, a plate). A line let fall as in the case of the Brachiopods (p. 118) will
divide the shell into two unequal parts.

DEVONIAN CORALS.

FIG. 67.

i. Heliophyllum Halli. 2. Eridophyllum simconensis. 3. Favosites goth-
iandica. 4. Syringopora elegans. 5. Aulopora cornuta. 6. Philipsastraea
Verneuili. 7. Zaphrentis prolifera.

CHEMUNG PERIOD.

are many beautiful ones belonging to the family of spiri-
fers. A peculiar coral, commonly styled the cup coral
(see 1 and 7, Fig. 67) is noticeable. It is horn-shaped, and
was occupied by a single polyp, which, Fig 68>
when alive, with its tentacles expanded,
must have been seven or eight inches in
diameter. Fish-bones are common in
some localities. A small trilobite (Pha-
cops bufo, lens-eyed toad) is conspicuous
because of the perfect preservation of its
eye lenses. Terrestrial plants are an in-
teresting feature, since they now first
appear in any abundance. Phacops bufo (ffaU).

CHEMUNG PERIOD.

JjOCCtHon. — The Chemung formation is found in New
York, and attains a great thickness in Pennsylvania.

ICinds of ffiocfc. — This period contains in New
York two epochs. (1). The Portage Group receives
its name from the celebrated falls in the Genesee River.
It consists of shales and sandstones, which are nearly
1000 feet thick at that locality. (2). The Chemung
Grovp, named from the Narrows in the Chemung *
River, is composed of coarse shales and shaly sandstones
of an olive or a greenish color. All the rocks abound in
ripple-marks, mud-cracks, and other proofs of broad, low
flats, swept by a muddy sea.f

* The name Chemung — meaning big horn — was given to it by the Indians be-
cause of a mammoth tusk which they found in the bed of the river.

t Hall well remarks, here quiet was required for the growth of the abundant
forms of Brachiopods and Lamellihranchs.

144 DEVONIAN AGE.

Fossils. — The Portage contains few fossils. The
Chemung, however, abounds in organic remains. Large
slabs are completely covered with impressions of shells.
Brachiopods and conchifers are plentiful, and occasionally
a trilobite or an orthoceratite is met. A prominent
brachiopod is the broad-winged spirifer, which is com-
monly known as a "petrified butterfly." It resembles the
one shown in Fig. 66. Beautiful fern impressions are
also presented — a prophecy of the abundant vegetation of
the Carboniferous Age.

CATSKILL PERIOD.

ZfOCation. — This formation constitutes the upper
range of the mountains after which it is named. It is
there perhaps 2500 feet thick, while south, along the
Appalachians, it is more than twice that thickness.

l£inds of *Kocfc. — The beds consist of shales and
sandstones, of a greenish or a reddish color, and often-
times gritty character. The harder strata of the sand-
rock sometimes weather in a peculiar way, dividing into
thin layers resembling a pile of boards.

FIG. 680.

Modiola Angusta (Vanuxem).

CATSKILL PERIOD.

Fossils. — There are few organic remains. Tiny
seams of coal, as in the Chemung rocks, indicate the pres-
ence of plants, while bones and scales of fish, often white
or blue, are conspicuous on the red-shale.

* — Geography. — New York and Wisconsin
were nearly finished. Interior Michigan was yet an inland
sea, while the ocean washed in unrestrained freedom the
vast area of the Mississippi valley. The Hudson and
Connecticut Elvers were perhaps formed, and the St.
Lawrence emptied into the sea near Montreal.

Scenic Description. —Let us try to picture to
ourselves a scene in the Devonian landscape. The air
is yet heavy with mist, and we strain our eyes to catch
a view of the land, like a voyager before whom, amid
the fogs and dews of early twilight, looms an unknown
shore. Gleams of light here and there reveal to us hill-
sides green with forests of lofty ferns and club mosses
of gigantic size. Insects, the only winged animals
yet created, flit in and out, enlivening the solitude with
their ceaseless hum. The rivers, fringed with tall, slender
rushes and reeds, look almost familiar ; but no grass car-
pets the meadows, no moss clings to the rocks, no flowers
deck the landscape.

The sea-shore, however, is stirring with life. Eurypteri
crawl over the slimy bottom, and, thrusting out their long
muscular arms, draw into their voracious maws sea-weeds,
fish, and other organic remains thrown up by the tide.
Innumerable fish, the armor-clad pirates of the Devonian
seas, impregnable against attack, dart through the water
in eager pursuit of their prey, which they crush between

IJfi DEVONIAN AGE

their poniard-like teeth. In the deeper waters the coral
tribes are busily at work, clearing the water and building
up the continent, while on the shallow, muddy bottoms,
shell-fish congregate in myriads, furnishing food for the
rapacious monsters of the deep.

Nowhere in the rocky book of Nature do we read a
page of quiet, free from pain or death. From the begin-
ning the flesh-eater preyed on the plant-eater, and, as now,
the weak succumbed to the strong. The struggle for ex-
istence began with its gift, and the reign of death was in-
augurated by the enjoyment of life. Thus only can
Nature preserve the equipoise between growth and decay,
between the means of subsistence and the development of
life.

FIG. 69.

Orthis hipparionyx.

DEVONIAN FOSSILS.
FIG. 690.

i. Dalmanites selenurus (Halt). 2. Cyrtoceras undulatum.
undulata (Hall). 4. Orthis lenticularis. 5. Atrypa reticularis.
Ichthyodolerite (a defensive fin-bone).

3. Strophomem
6. Section of an

DEVONIAN FOSSlLa
FIG.

i Cyrtoceras. Back view, showing the
undulating septae.

». Ichthyodolerite (fin-bone) of Ooon
daga Limestone (Hall).

CARBONIFEROUS AGE.

149

III. CARBONIFEROUS AGE.

(3. Permian Period.
CARBONIFEROUS AGE. •} 2. Carboniferous Period.

( i. Sub-carboniferous Period.

This age is so named from the abundance of coal
formed in its time.

FIG. 6qc.

A Carboniferous Fern (Sphenopteris Egyptiaca).

General Characteristics -.—At the beginning of
the age the growing continent had increased by the sue-

150 CARBONIFEROUS AGE.

cessive additions of the Silurian and Devonian Ages, so
that the shore-line of the Atlantic extended through
southern New York, thence west through the southern
part of Ohio, across the future Mississippi valley. The
Gulf of Mexico reached north to central Iowa. Lake
Superior was the only one of the great lakes in existence.
The pressure of the waters in the Atlantic and Pacific
oceans gradually deepened their beds and produced a
corresponding uplift of the future continent, so that after
a time the water drained off the site of the present
southern and the middle States south of the coast line
against which the warm water of the Gulf had beaten so
long. The low muddy tracts, the former sea-bottom,
became a wide extended marsh, warmed to a tropical
temperature by the internal heat. The atmosphere,
dense with moisture, and containing, in the form of
carbonic acid, all the carbon now locked up in the coal-
beds,* was rich in vegetable food. These favorable con-
ditions rendered the earth a very green-house, fit to teem
with luxuriant vegetation. This same acid, however,
would have been fatal to air-breathing animals. Hence
before they could be introduced, the atmosphere must be
prepared for their use. Here came a pause, as it were, in
the progress of the animal life of the world. The plant
must purify the air for the animal. The All-creative
Hand, suiting the means to the end, at once covered the
land with a new and teeming flora. Forests of strange
form and prodigious size sprang up as if by magic to
meet this new demand of Nature. No change of climate

* The atmosphere now contains 1 part in 2,500 of carbonic acid. According
to M. Brongniart, it had from 7 to 8 parts in 100 in the Carboniferous Era.

CARBONIFEROUS AGE. 151

varied the productions of the ground, but everywhere
flourished the same tropical growth. The crust of the
earth was unsteady, and frequent elevations and depres-
sions alternated. At one time it was lifted up to be
covered with vegetation, and at another sunk with the
ruins of the forests below the incoming ocean to receive
a deposit of sedimentary rocks. The theater of these re-
peated changes was the whole of the present coal area,
and much besides from which the coal has been swept
by subsequent denudation. During a season of verdure a
vast amount of vegetable debris, such as leaves, limbs,
fallen trunks, etc., accumulated, only to be overwhelmed
by the flood of sand, pebbles and mud washed in by the
rushing waters. The peat-deposit gradually changed to
coal, and the sediment hardened to shales, sandstone, or
clay. Sometimes the water became deep and clear
enough for corals or mollusks to exist, and Nature, suit-
ing the life to the new condition, populated the shallow
sea with swarming millions, and there a limestone was
interpolated.

Perhaps a hundred times in the course of the age this
process was repeated, and as many alternate layers
chronicled the changes in regular succession. In a Nova
Scotia coal-bed Lyell found in a portion 1,400 feet thick
no less than sixty-eight levels, showing as many different
old soils of forests, one above the other, where the trunks
of trees were still furnished with roots.

These characteristics culminated in the Carboniferous
Period of the age, being preceded by the Sub-carbonifer-
ous and followed by the Permian, in both of which the
land of these formations was submerged by the sea, re-
ceiving mainly rock deposits.

CARBONIFEROUS AGE.

SUB-CARBONIFEROUS PERIOD.

ZtOcation. — This formation is so named because it is
the base of the great carboniferous system of the con-
tinent. It is found in the Appalachian region, and west-
ward through Iowa, Illinois, and Mississippi.

J£inds of ffiocfc . — In the Appalachians it is a vast
deposit of sandstone and shale often several thousand feet
thick. At the West* it is a compact yellowish or grayish
limestone, of great thickness and wide extent. Thin
seams of coal sometimes occur, and these beds are known
as the False Coal Measures.

. — The limestone abounds in crinoids. No-
where else are these stone-lilies — the blossoms of the Sub-
carboniferous sea — found in such profusion and beauty.
There are also many brachiopods and fish remains. In

* The following are the subdivisions in Illinois as given by Worthen :

1. The Chester Group, 500 to 800 feet thick.

2. The St. Louis Group, 50 to 200 feet thick, which is cavernous. There are
many sink-holes in it near St. Louis showing the mouths of these caves.

3. The Keokuk Group, 100 to 150 feet thick. This contains numerous geodes,
varying from \ inch to two feet in diameter, lined with beautiful crystals of
quartz, calcite, etc.

4. The Burlington Limestone, 25 to 200 feet thick, which is almost a mass of
crinoids. Over 300 species of these " Lily stars " have been discovered and new
ones are constantly being brought to light.

5. The Kinderhook Group, 100 to 150 feet thick.

The Marshall Group, so named from Marshall, Michigan, is doubtless, in part
at least, of this period. It is worked at Cleveland and Waverly, Ohio, furnishes
the grindstones of Berea and Huron, and underlies the limestone bluff at Bur-
lington, Iowa. This is overlaid in Michigan by the Michigan Salt Group, which
underlies, like a great dish, the whole peninsula. In the Saginaw Valley, deep
wells were sunk for salt under the direction of Alexander Winchell, then State
Geologist, and the result amply vindicated the correctness of what was to him at
the time a mere scientific deduction. The Mountain Limestone, so well exposed
at Grand Kapids, is the highest group in the Sub-carboniferous.

CARBONIFEROUS PERIOD. 15S

England this rock is termed the Mountain Limestone.
When the stone is worn away by the elements, the round,
hard joints of the crinoids are found lying loose in the
soil, and are gathered and strung as beads by the children.*

. — /. Caves. — Several celebrated caves are
in this rock; for example, the Mammoth Cave, the
"Wyandotte Cave, etc. In many places in Indiana and
Kentucky, "sink-holes" are abundant, sometimes so
numerous as to interfere with plowing. These are open-
ings in the earth where the soil has been washed down
probably into subterranean caves never yet seen by man
The Mammoth Cave is the largest in the world. It has
been explored to a distance of over thirty miles. Views
of the grandest description are here presented. Royal
thrones, sparry grottoes, diamond arches, flowers of every
zone sparkling with crystalline beauty, here and there
reflect the light of the traveler's torch. Halls deco-
rated with fantastic pillars, and marble statues draped
with crystal mantles, charm with their magical splendor.
At one point the River Styx rolls its sad waters beneath

* Thus Sir Walter Scott, in allusion to the popular fable concerning this for.
siation, eays :

" But fain St. Hilda's nuns would learn
If on a rock by Lindisferne
St. Cuthbert sits, and toils to frame
The sea-born beads that bear his name :
Such tales had Whitby's fishers told,
And said they might his shape behold,

And hear his anvil sound, —
A deadened clang, a huge, dim form,
Seen but and heard when gathering storm

And night were closing round."

Hugh Miller humorously remarks that if St. Cuthbert made all these beads, he
must have been the busiest saint in the calendar.

154 CARBONIFEROUS AG£.

dark vaults, the windings of which are indented by a
thousand rocks. In its dismal depths gropes a kind of
fish— the Cyprinodon — which is blind, as it should be,
since of what service are eyes where absolute darkness
reigns ?

2. ^Reptiles.— In Sub-carboniferous rocks at Potts-
ville, Pa., the footprints of a reptile, having a stride of
thirteen inches, have been found. Later in the age, there
appear many advance scouts, as it were, of the reptilian
hosts of the succeeding age.

CARBONIFEROUS PERIOD.

. — The great coal-beds of the country lie in
six detached areas as seen in the Frontispiece. They are
styled respectively the Ehode Island, Appalachian, Michi-
gan, Illinois, Missouri, and Texas coal-fields. The Rhode
Island is the smallest, and comprises an area of only
1,000 square miles; the Missouri is the largest, and covers
100,000 square miles.— (Foster.)

ICinds of ftocfc. — The Carboniferous Period was
inaugurated by the formation of a conglomerate sand-
stone, the Millstone Grit.* During this era the Devonian
fishes and ferns were buried beneath vast deposits of sand
and gravel. Times of semi-emergence intervened, when?

* The ledges of this conglomerate often separated into huge blocks. Where a
portion has been swept away during subsequent geologic changes, the remains
present a striking resemblance to the streets and blocks of a ruined city. Sev-
eral of these so-called " Rock cities" are situated in southwestern New York.

THE CARBONIFEROUS PERIOD. 155

for a brief interval, the land was partially clothed with
vegetation. The coal-measures proper present stratified
rocks of every kind — sandstone, shales, limestone, etc.
They can be distinguished from Silurian or Devonian
strata only by the fossils. There is generally about one
foot of coal to fifty feet of rock. The thickness of the
coal-bed is at some places only that of paper, and at
others from thirty to forty feet. The " mammoth vein "
exposed to view at Wilkesbarre, and worked at Carbon-
dale, Mauch Chunk, Shamokin, etc., is 29J feet thick.*
The Pittsburg seam is 8 feet thick, and may be traced for
a long distance as a conspicuous black band along the
high banks of the Monongahela. The miners estimate
that a coal-bed gives 1,000,000 tons to the square mile
for every foot of thickness. Iron ore is also abundant.
Iron pyrites (Iron disulphide) is distributed either in
nodules, often of many pounds weight, or in thin seams,
so as greatly to injure the coal. The best quality of coal
contains a trace of this impurity, which gives the disagree-
able odor of coal-gas.

Fossils. — I. PLANTS are the characteristic fossils of
this period. Everywhere the shales bear impress of the deli-

* " The amount of vegetable matter in a single coal-seam six inches thick is
greater than the most luxuriant vegetation of the present day would furnish in
1,200 years. Boussingault calculates that luxuriant vegetation at the present
day takes from the atmosphere about half a ton of carbon per acre annually, or
fifty tons per acre in a century. Fifty tons of stone-coal, spread evenly over an
acre of surface, would make a layer of less than one-third of an inch. But sup-
pose it to be half an inch, then the time required for the accumulation of a seam
of coal three feet thick— the thinnest which can be worked to advantage— would
be 7,200 years. If the aggregate thickness of all the seams of coal in any basin
amounts to sixty feet, the time required for its accumulation would be 144,000
years. In the coal measures of Nova Scotia are seventy-six seams of coal, of
which one is twenty-two feet thick, and another thirty-seven," — Winches Geo-
logical

156 THE CARBONIFEROUS AGE.

cate tracery of ferns, leaves, stems, depicted with the
sharpest outlines.* Trunks of trees, erect or prostrate,
appear with their roots yet imbedded in the layer of clay,
the very soil in which they grew, underneath the coal.
These fossils reveal to us most perfectly the vegetation of
the Period. It is the fulfillment of that which scantily
appeared in the Devonian Age. It was almost entirely a
flowerless growth. The leading forms were tree-ferns,
rushes, and club-mosses, which grew to a size unknown
in our climate. If we should collect the cryptogams
(flowerless plants) of North America to form a forest,
it would hardly overtop a man's head, and the ferns
would have an undergrowth of toad-stools, mosses, and
lichens (Dana).

1. The Ferns. — Ferns which to-day creep at our feet,
then towered into stately trees, with trunks a foot and a
half in diameter. They are abundant fossils, and doubt-
less contributed most to the formation of coal.

2. The Calamites were jointed, rush-like plants. Un-
like the " horse-tail " or " scouring rushes " of the pres-
ent, which are rarely two feet long, their Carboniferous
prototypes shot up like a gigantic asparagus, with a
woody fiber, to a height of a score or more of feet. The
impressions of their huge prostrate stems are frequent.

* " The most elaborate imitations of living foliage upon the painted ceilings
of Italian palaces, hear no comparison with the beauteous profusion with which
the galleries of these instructive coal mines are overhung. The roof is covered
as with a canopy of gorgeous tapestry, enriched with festoons of most graceful
foliage, flung in wild irregular profusion over every portion of its surface. The
effect is heightened by the contrast of the coal-black color of these vegetables
with the light ground-work of the rock to which they are attached. The spec^
tator feels himself transported, as if by enchantment, into the forests of another
world ; he beholds trees of forms and characters now unknown upon the sur-
face of the earth, presented to his senses almost in the beauty and vigor of their
primeval life."— Dr.

THE CARBONIFEROUS PERIOD. 157

3. Tfie Sigillaria (seal - marked) is curiously orna-
mented with vertical ribs, along each of which is a row
of seal-like impressions. These are the scars left where
the leaves fell off. They wind in a spiral around the
trunk. The roots (stigmarice) are also dotted with scars.
They are generally found separate, though sometimes
combined with the parent tree. The sigillarian tree-
trunks frequently occur standing in coal mines. The
miners sometimes cut them off below, when their taper-
ing form permits the whole mass to descend upon the
workmen beneath. These " coal-pipes," as they are styled,
are therefore much dreaded.

4. The Lepidodendra (scaly-stems) — the club -mosses
of that time — were lofty trees, sixty feet high, with pitted
trunks and branches. The scars are arranged diagonally
or in a quincunx order.

5. Conifer sy or cone-bearing trees, were not infrequent,
with their boughs laden with fruit. Such was the vege-
tation which flourished in the Carboniferous Age, and
which we now use to warm and light our houses and to
drive our engines.

II. ANIMALS. — In a coal mine near the Bay of Fundy,
in the stumps of two sigillariae, there have been found the
remains of several small reptiles bearing frog-like and
lizard -like forms, a centipede, and the shells of a lancl
snail. These little creatures had probably crept into the
hollow trees for shelter, and were overtaken by the con-
vulsions which overwhelmed them. Several true reptiles
have since been identified. Traces of the spider, cock-
roach, scorpion, and May-fly with gauze wings 7 inches
broad, have also been discovered. Remains of fishes,

CARBONIFEROUS FOSSILS.

j. Calamites cistii.

3. Asterophyllites equisetifornus.

5. Sigillaria attenuata.

7. Pentremites

2. Archimedes Worthenn.

4. Actinocrinus Chrystii.

6. Pentremites godoni.

formis. 8. Pentremites Koninckana.

6, 7 and 8 are varieties of Crinoids.)

THE CARBONIFEROUS PERIOD. 161

brachiopods, crinoids and corals are abundant. (See
Fig. 70.)

Scenic Description.— In Fig. 71 is an at-
tempt to reproduce the characteristic features of a car-
boniferous landscape. On the right are two naked trunks
of a lepidodendron and sigillaria (whose foliage is entirely
unknown); between them is a tall tree-fern with its um-
brella-like top. At the foot of these great trees are
smaller ferns, and, in front, a stigmaria, whose curiously
dotted and branching roots reach out into the water. On
the extreme left is an asterophyllite, like the calamite,
with its gigantic bamboo-like trunk. Next is a conifer,
with a few pine-like branches. In front is a sigillaria,
and at its foot, prostrate, a sigillaria and a lepidoden-
dron mingled with ferns and vegetable debris. In the
centre is a clump of smaller lepidodendra. The back-
ground is filled with tall calamites. In the foreground
are the asparagus-like buds of young calamites just rising
out of the water. At the right several tiny stems of
asterophyllites show their pretty, finely-cut branches. In
the water float two fishes, and the archegosaurus shows
its long-pointed head.

What a strange scene is presented as we stem the
muddy current of the sluggish rivers, or thread the
mazes of those tropical jungles. It is as if the plants
of a wet meadow had shot up into forest trees. The
trunks, not gnarled and rough as in modern times,
spring up like the sculptured shafts of a medieval temple,
graceful in proportion and rich in ornament. Each col-
umn is embossed with its varied fluting spirals and ovals
of curiously intricate patterns. The tall ferns at every

162 THE CARBONIFEROUS AGE.

breath of wind wave their feathery crowns like beautiful
plumes. The scent of the morning air is hoi and damp
as that of a greenhouse. The sky, ever somber and
veiled, shuts down heavy with oppressive clouds. A wan
and dubious light scarcely makes visible the tangled
stems of lepidodendra and sigillarise, and sheds a vague
and shadowy hue of horror over the scene. The flowers,
few and inconspicuous, fail to enliven the somber tints
with a gayer color. No bird fills the air with music.
The shrill notes of insects and the croaking of amphi-
bians alone wake the echoes of this dismal forest.

THE PERMIAN PERIOD.

. — This formation is named from the an-
cient kingdom of Permia, in Russia, where it was first
recognized. It is wanting in the older States, but is
well developed in Kansas, and has been recognized in
Nebraska and Texas.

Kinds of jRocfc. — Limestones predominate, though
sandstone, shales, etc., are found. At Manhattan, Kan.,
a limestone is quarried from this series for architectural
purposes, which is so soft that it may be sawed with a
hand-saw and planed with a jack-plane, and yet is very
durable. It is the cheapest material of which the pioneer
can construct his house — cheaper even than it would be
to resort to the forest, if such existed, for logs (Foster).
Hay den notices the occurrence of a similar limestone,
and belonging to the same age, in Nebraska. The best
building material in England is the Permian lime-

TBE PERMIAN PERIOD. 163

stone of which the new houses of Parliament are con-
structed.

Fossils. — The Permian system is more a new rock-
formation than a new life-period. Many of its forms are
identical with those of the Carboniferous Period. The
air has been cleared by the action of the abundant vege-
tation, and the empire of animal life trembles between
the fishes and reptiles. The former are decreasing, while
the latter are increasing in size and number. Crocodilian
reptiles, their teeth set in sockets, mark the transitions of
the time. The coal flora has not entirely died, though
the coal-making epoch is passed; the low swampy lands
seem to have been raised so as to be unfavorable to its
growth, and no new vegetation fills the place. It is near-
ing the close of the great Paleozoic Time. Older forms
are dying, and the Creator develops no fresh world-
thoughts to mark the dawn of a new era. The coal is
stored in the earth, and the continent now moves forward
in its preparation for the advent of man, for whom it has
been so wonderfully contrived.

.— /. AppalacJrian 3tevo2ulio?i . — The

close of the Paleozoic Age was marked by a grand up-
heaval. Few if any animals or plants survived the catas-
trophe.* The contraction of the earth's crust caused by
its gradually cooling or, as some geologists think, the

* It should be noticed that a very large school of geologists hold that Nature
moves always by imperceptible stages and not by sudden bounds ; that hence
such phrases as "general extinctions " and such words as "catastrophe" and
" convulsions " are rarely, if ever, true to fact ; and that the Appalachian Revolu-
tion itself was accomplished not by a violent disruption, but by a slow move-
ment of perhaps only a few feet or yards in a century. In a sentence there may
be condensed the work of an age.

164 CARBONIFEROUS AGE.

tremendous pressure of the two oceans, had kept the
newly-formed continent continually vibrating to and fro;
but at last the tension was too great, and the crust was
gradually but irresistibly upheaved in gigantic folds
thousands of feet high, extending from Vermont to Ala-
bama. The Appalachians,* being nearest the Atlantic
force, were thrown up far higher than they are at present,
often toppling over from their dizzy heights, while more
gentle elevations were made toward the central portion of
the continent. Since then many of these folds have been
denuded.f

Mesomorphic Action.— During this fearful and
probably long-continued earth-storm the horizontal coal-
beds were not only folded and dislocated, but also lifted
above their former level. An evolution of the internal heat
with, perhaps, also the heat produced by the motion of the
rocks, metamorphosed the bituminous coal into anthracite.
This effect, like that seen in the rock strata, was most

* According to Dana, the material of the Appalachian Mountains was depos-
ited gradually, through the preceding ages, in a trough caused by the slow set-
tling of the earth in that region until it had reached a depth of 40,000 feet. During
the Appalachian Revolution the crust, weakened by the melting off below, col-
lapsed, and the deposits of the trough were forced together, folded, and meta-
morphosed as above described. Hunt holds that in general the folding and ele-
vation of strata are merely incidental and not necessary to the formation of
mountains. The sculpturing agents (see p. 87), which have carved out the earth's
present features, have left the hills while digging out the rest of the land. The
mountains, in such cases, are the remains of great table-lands, which have been
swept away in subsequent geologic changes.

t A striking illustration, occurring near Chambersburg, Pa., has already been
alluded to on p. 82. At that point, along a fracture of twenty miles in extent,
rocks of the Upper Silurian lie opposite those of the Lower. A man can stand
astride the crevice with one foot on Trenton limestone and the other on
Hamilton slates, and, in addition, put his hand on some great fragments of Oneida
conglomerate, caught as they were falling down the chasm, and held in its earth-
quake jaws. All the strata between these two extremes, at the time of the Ap-
palachian Revolution, must have formed an immense wall 20,000 feet high and
twenty miles in length.

THE PERMIAN PERIOD. 165

felt near the Atlantic coast; hence we find anthracite
coal in the Appalachian Mountains, next semi-bitumin-
ous, and in the western area bituminous coal alone. The
same metamorphic force, where greatest, as in the eastern
States, produced granite, gneiss, and other crystalline rocks.
Nine-tenths of the rocks on the surface of the globe were
made prior to this period. Many of these beds during
this revolution were crystallized, and also stored with
mines of gold, tin, copper, lead, etc., thus fitting them
for the purposes of art and commerce.

2 . ^Progress of .Life . — We have beheld seas — vast
watery deserts — become densely populated. We have
traced the Creative thought slowly advancing among
the ruins of ages. The five types of structure have
all been introduced, and all, except the vertebrate, devel-
oped to their higher orders. The lower forms have, one
ay one, given place to the higher. We now pass over a
chasm to where the distinctions stand out in bold relief.
We take leave of the trilobites, graptolites, orthoceratites,
eurypteri and corals of the Silurian seas, of the mail-
encased fishes of the Old Red Sandstone, of the sigil-
lariae, stigmariae, and lepidodendra of the Carboniferous
jungles, and go forward to meet higher forms of life
more nearly resembling those of the present age. The
Paleozoic types fade away in the world's progress to its
brighter future. "As the stars sink, one by one, in the
west, and new stars rise in the east, to be succeeded by
the dawn and then the day, so through the night of the
past sank the old life-forms, to be succeeded by the new,
approaching nearer to the dawn of the day in whose
morning we live." (Denton.)

166 THE AGE OF HEP TIL £8.

fHE HESOZOIC |IME.

The Mesozoic or Middle-life of Geologic History com.
prises but one age, that of reptiles.

[ 3. Cretaceous Period.

THE AGE OF REPTILES. -J 2. Jurassic Period.

( i. Triassic Period.

General CJiaraclerislics . — A new cycle now
begins.* The five grand old types of life remain, but
they are to be presented under new and more familiar
features. The four orders of vertebrates are at last to
be completed. The air becoming purified for land
animals, a flora arises capable of supporting a more
abundant fauna. Birds, mammals, common or bony
fishes, palms and flowering plants are to appear. The
Paleozoic plants expanded and made their develop-
ment mainly in the sculptured stem; the Mesozoic,
in the beauty of fruit and flower. The Paleozoic corals
had rays or arms arranged in fours', the later corals,
in sixes. The Paleozoic chambered shells had plain
and simple divisions; the later shells have intricately-

* The " differentiation," as it is called, of the vital functions now became
more marked, i. e., instead of organizations, in which several functions are per-
formed by the same organ, each function has an organ specially devoted to its
use. There was also a progress in " Cephalization," or head-development. Ex-
ternal characteristics appeared, which are so apparent that " if the Paleozoic and
Mesozoic fossils were arranged on opposite sides of a museum," says Page,
" the difference would strike an observer as would that between the brute-man
sculptures of Nineveh and the man-god of the Greeks and Komans."

TRIASStC ANti JURASSIC PERIODS. 167

folded ones. The Paleozoic fishes had tails unequally
lobed ; since then, the equally-lobed or undivided tail has
been the usual form. Aside from these general features,
the distinguishing characteristic of the Mesozoic Time is
the extraordinary development of reptiles. These ani-
mals astonish us by their vast number, gigantic size, and
unwonted appearance. Through those antique forests
enormous lizards, forty to fifty feet in length, dragged
their ponderous bodies, — the modern representatives of
which are inoffensive little creatures a few inches long,
that seek only to hide from our view in the grass.

Geography. — The continent has grown by the
addition of the Carboniferous area. The Appalachian
region has been uplifted above the sea. The scene of
rock-making is pushed to the borders of the Atlantic and
the Gulf, and to the slopes of the Eocky Mountains. The
accompanying map is an attempt to show some of the
outlines of the Mesozoic continent. New England was a
peninsula. The beautiful valley of the Connecticut was
an arm of the ocean, with broad, flat, muddy shores.
The Gulf States were out afc sea. The Gulf of Mexico
swept along the eastern flank of the yet emerging Eocky
Mountains to the Arctic Ocean, while the Pacific Ocean
washed the site of the future Sierra Nevada. New Jersey,
Maryland, Delaware, North and South Carolina, were as
yet only half made. (See Fig. 72.)

TRIASSIC AND JURASSIC PERIODS.

These groups are not fully separated in America. The
Triassic (triple) takes it name from the fact that, in Ger-

168

THE AGE OP REPTILES.

many it is composed of three distinct groups.* It is
sometimes termed the New Red Sandstone, to distinguish
it from the Old Red Sandstone of the Devonian. The
Jurassic is so called because it is extensively developed in
the Jura Mountains, Switzerland. The foreign divisions
are the Lias, Oolite, and Wealden.

The Mesozoic Cont

Z,ocation. — lK the United States the rocks of this
period are found along the Connecticut Valley from

* The Bunter Sandstein or colored sandstone, the Muschelkalk or mussel
chalk, and the Keuper, a miner's term, meaning a group of red and green marls
and shell H.

TRIASSIC AND JURASSIC PERIODS. 169

Long Island Sound to the northern boundary of Massa-
chusetts ; thence they may be traced from the Palisades
on the Hudson, in long, narrow, scattered strips through
New Jersey, Pennsylvania, Virginia, and North Carolina.
(See Frontispiece.) They probably occupy the synclinal
valleys running north and south, left between the great
folds of the Appalachian Eevolution. During that time
they were under the water, and formed deep inland bays,
receiving the washings from adjacent hills to work into
rock formations. The beds are from 3,000 to 6,000
feet thick; hence these valleys must have constantly set-
tled and as steadily filled with the accumulating sedi-
ment. The great Pacific Triassic belt extends from
Mexico to British Columbia, through a width of per-
haps four degrees of longitude (Whitney). The rocks
are also found extensively in Colorado and Nevada.

J^inds of ffiocfc. — The rocks of the Connecticut
valley are principally sandstones, which are extensively
quarried for the " brown-stone fronts " of New York city.
The popular " free-stone " of Portland, Conn., and New-
ark, N. J., is a Triassic rock. Near Eichmond, Va., and
Deep River, N. C., are valuable coal beds in the rocks of
this era. At the west this formation consists of beds of
brick-red marl and sandstone. The celebrated Solen-
hofen limestone, so much used in lithography, is of the
Jurassic Period.

Fossils. —The organic remains are of the most varied
and wonderful description. They reveal very clearly the
plant and animal life of these periods.

I. PLAKTS. — The vegetation included numerous varie-

110

THE AGE OP REPTILES.

ties of ferns, conifers, and calamites, which formed
graceful forests, as in the Carboniferous Period; but
there were no jungles of lepidodendra or sigillarise. In-
stead of these, the Cycad appeared. This had a short
trunk, and at the top a tuft of branching leaves (Fig. 82,
left of the center). In shape, the leaves resembled those
of the palm, but did not split lengthwise, while they
unrolled from a coil, like those of the fern. The struc-
ture of the wood and fruit was like that of the conifers.
The cycad, combining thus characteristics of three orders
of plants — conifers, ferns, and palms — is another illus-
tration of what we have termed a comprehensive type.

II. ANIMALS. — Birds and mammals make their first
appearance, completing the last and highest order of
animals. Spiders, beetles and other insects have been
discovered, and even their tracks in the soft mud have
been preserved. Fish remains are plentiful, as at Sun-

FIG. 73.

FIG. 74.

Ostrea Marshii. Middle O51ite.

Trails ot Insects and Prints of
Rain-drops.

derland, Mass. Fig. 73 represents an Oolitic oyster, the
progenitor of our modern bivalve. Marine life seems

TRIASSIC AND JURASSIC PERIODS. 171

wanting in this country, but the European rocks contain
a prolific record of the Mesozoic seas. Crinoids were
abundant ; one of these, the Lily Encrinite, is especially
beautiful (Fig. 75)0 The cephalopods reached their cul-
mination in the ammonite and belemnite.
FIG. 75-

Encrinus (krinon, a lily) liliiformis.

The Ammonite is the fully coiled and perfected or-
thoceratite of the Silurian seas. It derives its name from
its resemblance to the horn which decorated the front
of the temple of Jupiter Ammon and the bas-reliefs and
statues of that pagan deity. It is found of all sizes, from
that of a pin's-head to a cart-wheel. The shell is thin,
but strengthened by many sinuous partitions (septa),
which add to its beauty and strength.* This curious
internal archwork, by its joinings with the external shell,

* The economy of the Ammonite designed it to live mainly at the bottom of
deep waters, but to be able to rise at pleasure to the surface. For this purpose
the outer chamber (o o) (Fig. 76) of the wreathed shell was fitted for the reception
of the animal, while the interior chambers (i i) were hollow, so as to make the
whole structure nearly of the same weight as the element in which it moved.
Through all of these chambers an elastic tube passed by means of a pipe or
siphuncle (s s), the tube being in connection with the cavity of the heart, which,
under ordinary circumstances, was filled with a dense fluid. When alarmed, or
wishing to descend, the animal withdrew itself within the outer chamber, and
the pressure upon the cavity of the heart forced the fluid into the siphuncle, so
as to increase the gravity of the shell, by which means it readily sunk to the
bottom. On the other hand, when wishing to ascend, it had only to project its
arms, and the fluid, being freed from the pressure, returned from the siphuncle
to the cavity of the heart, thus restoring the whole structure to its ordinary
floating gravity. As the pressure of water at the sea-bottom would break any
ordinary shell, we perceive that the septa were essential to the preservation of
the little animal, enabling it to resist a weight which would otherwise crush it

172

THE AGE OF ItEPTILES.

adorns it with graceful figures resembling the most deli-
cate foliage or embroidery. The chambers are often
found lined with quartz crystals, making tiny geodes of

FIGS. 76-7.

. ^^^

i. Ammonites obtusus ; 2. Section of Ammonites obtusus, showing the interior cham-
bers and siphuncle ; 3. Ammonites nodosus.

exquisite beauty, while the edges of the partitions, being
converted into iron pyrites, form a kind of golden tra-
cery, glittering in the midst of the pellucid spar. The
only surviving member of this family is the modern
nautilus (naus, a ship), the "fairy sailor" of the Indian
seas.

The Belemnite (Memnon, a dart) is so called from the
peculiar shape of its fossils (Fig. 78). They have also

FIG. 78.
||$^

••#• f

:&',

Belemnitella mucronata, Cretaceous Period, N. J.

been vulgarly called " thunder-heads," " lady-fingers," etc.
The relics do not give any idea of the animal to which
the name was applied. They were merely the terminal
bones of the body and were surrounded with flesh. The

TRIASSIC AND JURASSIC PERIODS. 173

FIG. 79.

animal resembled the modern cuttle-fish.* It secreted
a kind of ink which it used as a means of defence.
In an emergency, it blackened the
water in its vicinity, and escaped
from sight. These ink-bags have
been found so perfectly preserved
that their contents have been used
in sketching their fossil remains.

The enormous reptiles are, how-
ever, the distinguishing fossils of the
age. We shall notice only the more
prominent ones.

1. The Ichthyosaur (fish-lizard) is
a striking illustration of a compre-
hensive type, having the general con-
tour of a dolphin, the snout of a
porpoise, the head of a lizard, the
jaws and teeth of a crocodile, the
vertebrae of a fish, the sternal arch
of the water-mole,f the paddles of
a whale, and the trunk and tail of
a quadruped. Its habits were doubt-
less aquatic, while, like the whale,

., , ,11 T . Belemnite restored; a, the

it breathed atmospheric air, and was ink-bag in place.

* All are familiar with " cuttle-fish bones," so commonly used as food for
canary birds. The substance, it is well to observe, is not a "bone," nor de-
rived from a true " fish." It is simply the rudimentary shell of a mollusk.
The cuttle-fish of our own shores is a harmless animal, only ten or twelve
inches long, but the one frequenting the African seas attains a formidable size.
This is the " devil-fish," so graphically described by Victor Hugo. Its staring,
glassy eyes strike terror to beholders. It has eight huge, muscular arms, many
times the length of its body, with which it holds its prey in a grasp so tenacious
that the arms have been severed before they would yield.

t The ornithorhynchus or water-mole of New Holland is a mammalian-furred
quadruped with webbed feet and the bill of a duck. In this animal the Creator
seems to have repeated the curious contrivance originally provided for the
Ichthyosaur. (See Fourteen Weeks in Zoology, p. 109.)

THE AGE OF REPTILES.

thus compelled to come frequently to the surface of
the water. Its neck was short and thick, its head
large, and its body twenty or thirty feet long. Its
jaws had an enormous opening, some having been
found with 160 teeth, which could be renewed many
times, as above each tooth was always the bony germ
of a new one. The eyes were often two feet in diam-
eter. Surrounding the pupil of each one was a circu-
lar series of thin bony plates. This apparatus, which
still exists in the eyes of turtles and lizards, could be
used to increase or diminish the curvature of the cornea,
and adapt the magnifying power to the wants of the
animal. The eye could thus be used as a telescope or
a microscope to see its prey far and near, and to descry
it in the darkness and depths of the sea. The fossil ex-
crements of the Ichthyosaur are styled coprolites, and
when polished are sold as jewelry.* They reveal dis-
tinctly the food and the internal organism of this Meso-
zoic saurian. In them have been found the scales and
bones of smaller animals of their own species. The quar-
ries of Lyme Regis, in Dorsetshire, England, abound in
the remains of the Ichthyosaur. f

* Under the name of "beetle stones" coprolites have also been used for
artistic purposes. Dr. Buckland, the celebrated English geologist, had a table
in his drawing-room that was made entirely of these fossils, and was often much
admired by persons who had not the least idea of what they were looking at.
"I have seen," says his son, "in actual use, ear-rings made of the polished
portions of coprolites (for they are as hard as marble) ; and while admiring
the beauty of the wearer, have made out distinctly the scales and bones of the
dsh which once formed the dinner of a hideous reptile, but now hung pendulous
from the ears of an unconscious belle, who had evidently never read or heard of
such productions."— Buckland1 s Curiosities of Natural History.

t In 1811, Mary Anning, a poor country girl, who made her precarious living
by picking up fossils, for which the neighborhood was famous, was pursuing
her avocation, hammer in hand, when ehe perceived some bones projecting a
little out of the cliff. Finding, on examination, that it was part of a large skele-

••••P1

TRIASSIC AND JURASSIC PERIODS. 177

2. The Plesiosaur had the head of a lizard, the teeth of
a crocodile, the neck of a swan, the trunk and tail of a
quadruped, the ribs of a chameleon,* and the paddles of

FIG. 81.

A Coprolite.

ton, she cleared away the rubbish, and found the whole creature imbedded in
the block of stone. She hired workmen to dig out the block of lias in which it
was buried. In this manner was the first of these monsters brought to light ; a
monster some thirty feet long, with jaws nearly a fathom in length, and huge
saucer eyes— which have since been found so perfect that the petrified lenses
have been split off and used as magnifiers.

Hugh Miller gives the following graphic description of the lias of Scotland :
"It consists of laminae as thin as sheets of pasteboard, which, of course, shows
that there was but little deposited at a time, and pauses between each deposit.
Yet never did characters or figures lie closer on a printed page than the organ-
isms on the surfaces of these leaf-like laminae. We insinuate our lever into a
fissure, and turn up a portion of one of the laminae, whose surface had last seen
the light when existing as part of the bottom of the old Liassic sea, when more
than half of the formation had still to be deposited. The ground of the tablet is
of a deep black, while the colors of the fossils stand out in various shades, from
opaque to a silvery white or deep gray. There, for instance, is a group of large
ammonites, as if drawn in white chalk ; there, a cluster of minute bivalve
shells, each of which bears its thin film of silvery nacre. We turn over another
page. Here are ammonites of various sizes, but all of one species, as if a whole
argosy had been wrecked at once and sent to the bottom. And here we open
yet another page, which bears a set of extremely slender belemnites. They lie
along and athwart, and in every possible angle, fike a heap of boarding-pikes
thrown carelessly down a vessel's deck on the surrender of her crew. Here, too,
is an assemblage of bright, black plates, that shine like pieces of Japan work,
the head-plates of some fish of the ganoid order ; and here an immense accumu-
lation of minute, glittering scales of a circular form. And so, leaf after leaf, for
tens and hundreds of feet together, repeats the same strange story. The great
Alexandrian Library, with its unsummed tomes of ancient literature, the accu-
mulation of long ages, was but a poor and meager collection, scarce less puny in
bulk than recent in date, when compared with this vast and wondrous library of
the lias of Scotland."

* Each pair of ribs surrounded the body with a complete girdle formed of five
pieces, thus affording great facility for the expansion and dilation of the lungs.

178 THE AGE OF REPTILES.

a whale. Its tail was shorter than that of the iclithy-
osaur, being only sufficient to act as a rudder in guiding
the body. To compensate this loss and assist in propul-
sion, its paddles were much larger and more powerful.
Its appearance presented a striking contrast to that of its
more ponderous foe, the ichthyosaur, whose attacks it
could escape by sinking to the bottom, while its long
neck reached to the surface of the water and maintained
respiration.

3. The Pterodactyle (wing-fingered), in its apparent
monstrosity* surpassed even the two reptiles just men-
tioned. It was so named because the bone of one finger
was greatly expanded in order to support an extended
membrane for flying (Fig. 82). It was a true aerial
reptile. Its wings resembled those of bats. Its bones
were hollow, like those of birds, but it bore no feathers,
and had a mouth full of teeth. Remains have been found
indicating a spread of wing of not less than sixteen feet ;
but the usual species of the Liassic did not exceed ten
inches in length. Its ordinary position was upon its
hind feet, walking uprightly with folded wings, or
perched on trees, or climbing along cliffs with its hooked

* The fins of the fishes of the Devonian seas became the paddles of the ichthy-
osaur and of the plesiosaur ; these, in their turn, became the membranous foot
of the pterodactyle, and, finally, the wing of the bird. Afterwards came the
articulated fore-foot of the terrestrial mammalia, which, after attaining remark-
able perfection in the hand of the ape, became, finally, the arm and hand of man,
an instrument of wonderful delicacy and power, belonging to an enlightened
being gifted with the divine attribute of reason 1 A careful examination of the
fore paddles of the plesiosaur reveals all the essential parts of the human arm—
the scapula, humerus, radius and ulna, the bones of the carpus, the metacarpus
and the phalanges. Was not this a prophecy of man? "Let us, then, dismiss
this idea of monstrosity, which can only mislead us, and not consider antedilu-
vian beings as mistakes or freaks of nature. Let us not regard them with dis-
gust ; let us learn, on the contrary, to behold in them with admiration the divine
proofs of design which they display, and, in their organization, to see the handi-
work of the sublime Creator of all things,"

TRIASSIC AND JURASSIC PERIODS. 181

slaws and feet. The smaller ones lived on insects, but
the larger probably pounced on struggling reptiles, or,
diving into the water, preyed on fish. More than twenty
species of the pterodactyle have been discovered in the
old world, but in the new there have been found only a
pair of finger-bones, at Phoenixville, Pa.* Poets have long
pictured to us a flying dragon of the olden time, which
played a conspicuous part in pagan mythology. It
breathed fire, poisoned the air with its exhalations, and
disputed with man the possession of the earth. In the
Jurassic times we find the realization of this creature
of poetic fancy, but it is only an uncouth reptile, utterly
unworthy of those fabled conflicts in which gods and
heroes shared.

4. The Dinosaurs (terrible lizards) were land reptiles
of enormous size that roamed elephant-like over the
river-plains, or browsed in the forests of the Oolitic and
Wealden Epochs. These included the megalosaur (large
lizard), hylaeosaur (wood-lizard), iguanodon, etc. (Fig.
83), huge monsters from forty to seventy feet in length.
The megalosaur was carnivorous, having teeth curved
backward like a pruning-knife, and with a double edge
of enamel so as to cut like a sabre equally on each side.
The iguanodonf (ig-wan-o-don) was herbivorous, twigs of
cypress having been found fossil in its stomach, and
its teeth often being half-worn to the roots.

* The pterosaurs (pterodactyls) or flying lizards, found by Marsh in the creta-
ceous rocks of Kansas, had toothless jaivs sheathed with horn, as in birds, and
some possessed a wing-expanse of 25 feet.

t A party of twenty-one scientific men, at the invitation of Dr. Hawkins,
once took dinner within the restored body of this animal. On that occasion
Dr. Owen, the celebrated geologist, sat in the head for brains ! This model
contains 650 bushels of artificial stone, 100 feet of iron hooping, 600 bricks, 20
feet of inch bar iron, 900 plain tiles, and 650 two-inch, half-round drain tiles ;
while the legs are four iron columns, nine feet long and four inches in diam-
eter. (" Penny Guide to the Crystal Palace at Sydenham.")

182 TEE AGE OF REPTILES.

FIG. 83.

The Megalosaur and Hylaeosaur. Restored by Hawkins.

There is a restoration of a megalosaur in the Crystal
Palace at Sydenham, England. This model was con-
structed under the direction of B. Waterhouse Hawkins.
On the back of the animal is a hump like the withers
of a horse. (See p. 269.) From the few bones discov-
ered at that time, this celebrated anatomist decided that,
to make the huge head effective, a mass of muscle and
bone on the fore shoulders was essential. This bunch
was thought by other geologists to be a mere monstrosity
of his own invention. Subsequently, the dorsal vertebrae
being found, the conclusion was proved to be correct.

5. The Labyrinthodon was a frog-like quadruped, often
attaining the size of an ox. It is so named because the
outer coating of its teeth was bent inward in intricate
mazy folds. Its head was protected by a helmet, and its
body by a scaly armor.

The Ramphorhyncus, the remains of which have
been found in the quarries of Solenhofen, is a curious
intermediate link between birds and reptiles. Its tail,

TRIASSIC AND JURASSIC PERIODS. 183

a singular appendage shown in the figure, was long,
reptile-like, and dragged upon the ground, while its foot-

FIG. 84.

Labyrinthodon of the Trias restored, with its foot-prints.

prints were bird-like. Stranger still, the Kansas rocks of
the next period have afforded Marsh remains of a bird
with its mouth full of teeth set in sockets.

FIG. 85.

The Ramphorhyncus, with OOlitic Vegetation.

184

THE AGE OF REPTILES.

Bird-tracks •- --In the red sandstones of the Connecticut
valley, numerous foot-prints have been found, described

FIG. 86.

Imprints of Feet, Turner's Falls, Massachusetts.

TRIASSIC AND JURASSIC PERIODS. 185

by Hitchcock as mainly the tracks of birds. The
number of these foot-prints is wonderful. Tracks of
many different sizes and species often traverse the same
slab. The largest tracks are fifteen inches long, and
so deep as to hold nearly two quarts of water. They
were made by an animal walking erect and having a
stride of three feet. Hitchcock estimates that it far ex-
ceeded the ostrich in size, being at least twelve feet high,
and weighing from 400 to 800 pounds. From the fact
that parallel rows of tracks are found, we infer that these
strange bipeds frequented in flocks the shores of the Con-
necticut, and waded into its shallow waters in quest of
the fish and mollusks of the Mesozoic types, now long
extinct.* Geologists are divided in opinion ay to whether
any of these tracks were made by birds, and not rather
by three- toed reptiles somewhat similar to the ramphor-
hyncus. (Fig. 85.)

.— /. Ctimate.—The Gulf Stream, sweep-
ing northward through the center of the continent,
combined with the other causes already named to
ameliorate the climate so as to permit a sub-tropical
growth as far north as latitude 60°. Corals and ammo-
nites, now restricted to torrid seas, then flourished in the

* u It is a solemn and impressive thought that the footprints ol these dumb and
senseless creatures have been preserved in all their perfection for thousands of
ages, while so many of the works of man which date but a century back have
been obliterated from the records of time. Kings and conquerors have marched
at the head of armies across continents, and piled up aggregates of human suf-
fering and experience to the heavens, and all the physical traces of their march
have totally disappeared ; but the solitary biped which stalked along the mar-
gins of a New England inlet before the human race was bora, pressed footprints
in the soft and shifting sand which the rising and sinking of the continent could
not wipe onV—Winchell.

186 THE AGE OF REPTILES.

valley of the Upper Mississippi, while the prairies of Ohio
and Illinois were green with perennial palms and pines.

2 '. Salt Heds. — The most extensive salt deposits in
Europe are of the Triassic Period, and it has hence been
sometimes styled the Saliferous formation. In Cheshire,
England, are two beds of rock salt, each nearly 100 feet
thick. At Cardona, Spain, is a mountain of salt several
hundred feet high. This salt rock is pure as glass, and is
carved into images, cups, etc., for sale to travelers. At
the base is a brook, which in rainy seasons swells into a
river, and carries down so much salt as to destroy the
fish.* The mines of Cracow, Poland, have been worked
at a depth of over 1,000 feet in galleries whose total
length is 500 miles. At one point is a village with
streets and houses, and even a chapel with altar, pulpit,
statues, etc., all hewn out of the solid rock. The deposits
in the salt beds indicate that the same conditions existed
in portions of Europe during the Triassic as in New
York during the Salina' Period.

3 '. The Gold-bearing ftocfcs of California

are mainly Jurassic or Triassic metamorphic sandstones,
with interstratified quartz containing gold. Where the
quartz veins have come to the surface and weathered, the
particles of gold have been washed out, and thus formed
the auriferous sands. There are frequent dikes of trap
and outcrops of granite. On the crests of the Sierra
Nevada these masses of granite often assume a dome

* This mountain presents a wondrous beauty to the looker-on at sunrise.
Aside from its graceful and majestic form, it seems to rise above the river like a
mountain of precious gems, displaying the brilliant colors of the rainbow.

THE CRETACEOUS PERIOD. 187

shape, and reach a height of 15,000 feet above the sea-
level.

£. disturbances. — Long-continued upheavals and
perhaps even terrific convulsions attended the close of
this era, whereby such stupendous mountain ranges as
the Sierra Nevada, Sierra Madre, etc., were lifted above
the interior sea. The trap rocks of Mts. Holyoke and
Tom, East and West Rocks near New Haven, Conn.,
the Palisades on the Hudson, and Bergen Hill in New
Jersey, are all illustrations of the wide extent of the
igneous action. Everywhere trap dikes and ridges at-
tend this formation. The proofs that the trap was
thrown out in a melted state are abundant. The adja-
cent sandstone has been baked by the heat, the layers
uplifted by the escaping steam, and the fissures often
filled with crystallized minerals.

CRETACEO US PERIOD,

. — The Cretaceous rocks occur on the At-
lantic coast from New York to South Carolina, along
the Gulf through Texas, far northward over the slopes
of the Rocky Mountains, and along the Pacific coast
westward of the Sierra Nevada. (See Frontispiece.)

J£inds of ffiocfc. — The name is derived from
the Latin creta, chalk. The famous white "Cliffs of
Dover" are of this formation. On our continent
this group contains no chalk except a single bed in
western Kansas. The Cretaceous rocks are mostly sand-
stone, of various colors — white, green or red — and often

188 THE AGE OF REPTILES.

so loose that they may be rubbed to pieces with the hand
or dug with a spade. Beds of "green sand" are abundant
in New Jersey. This
is composed of small
rounded grains, con-
sisting mostly of sili-
cate of iron and potash.
The peculiar shape of
these granules is prob-
ably due to the fact
that they are the casts
of microscopic shells.
It is termed marl, and
is extensively used for
fertilizing purposes. In

A common Fossil of the Green Sand— the Exo-

western Texas are beds gyracostata.

of cream-colored lime-
stone called " Chimney Stone," from its use in building
chimneys. When taken from the quarry, it is soft
enough to hew with an axe or smooth with a plane.
Valuable mines of coal, (lignite) * and quicksilver are
found in California.

Fossils. — If we examine chalk with a powerful mi-
croscope we shall see that it is composed largely of the
minute shells of various species of rhizopods \ (foraminif-

* The Great Lignite Group of the Rocky Mountains, heretofore known as the
Tertiary coals (see p. 198), are now referred by some of the best authorities to
the Cretaceous Period. Read Stevenson's report on the Geological Relations of
the Lignitic Group.

t The imagination fails to conceive the countless millions of these foraminif-
era in all ages. In Nature nothing is small. She seems to have delighted in
achieving the grandest results with the feeblest means. The history of this ani-

THE CRETACEOUS PERIOD.

189

era), so tiny that their very smallness seems to have
rendered them indestructible. Eighteen hundred of

FIG. 88.

Chalk of Gravesend (Ehrenberg).

these placed in a row would occupy but an inch of
space. Schleiden says that the chalk on a visiting card

malcule is a striking illustration of this truth. A handful of sand taken up on
the sea-shore is often half composed of these microscopic shells. The Paris
chalk contains them so abundantly that D'Orbigny found 58,000 in a cubic inch of
the rock. Paris itself is built up of these cast-off abodes of the tiny rhizopod.
The species vary in different sections and ages. A curious application of this
has lately come to notice. Ehrenberg was requested to assist in tracing the
robbery of a case of wine. It had been repacked by the criminal in sand differ
iag from that in the original case. Ehrenberg, by a microscopic analysis, deter-
mined that the sand was found only on a certain ancient sea-coast in Germany.
On this fact being discovered, the locality of the crime was speedily found and
the thief arrested.

190 THE AGE OF REPTILES.

is a microscopic cabinet of a hundred thousand shells,
Throughout the beds of chalk are scattered nodules of
flint, which, being broken, reveal at the center shells,
corals, etc., the nuclei around which the flint collected
oyt of the chalk before that had consolidated from the
pasty mass in which it first formed on the sea-bottom.

1)eep-Sea Soundings show that the bottom
of the North Atlantic, where not deeper than 15,000 feet,
is covered with a fine ooze, 85 per cent, of which is com-
posed of rhizopod shells. This " abysmal mud " is similar
in character to chalk, and some of the shells as well as
siliceous sponges which it contains are identical with
cretaceous forms. The conclusion is, therefore, obvious
that the deep-sea bed of the mid- Atlantic has remained
submerged since the Mesozoic Time, and a part of the
Cretaceous fauna has thus been preserved to the present
day unchanged. In this sense of the phrase alone, we
may be said to be now "living in the Cretaceous Pe-
riod."

THE AMERICAN FOSSILS are far removed from the
microscopic remains of the Old World. While chalk-
beds were accumulating on the deep-sea bottom in Eu-
rope, the shallow waters on the American shore teemed
with as busy and strange a life as swarmed upon the
coasts of England, France or Germany during the entire
Mesozoic Age. The Cretaceous beds of New Jersey have
furnished abundant reptilian remains.*

1. The Cimoliasaur and the Elasmosaur were huge

* We are indebted to the untiring and skilful labors of Dr. Cope and Dr. Leidy.
Of Philadelphia, for the following description of these Cretaceous reptiles.

THE CRETACEOUS PERIOD. 191

sea-serpents, twenty-five to forty feet long, with bodies
larger than an ox, sharp teeth, and flippers like a whale,
— the latter having a flattened tail, which it used like an
oar for sculling.

2. The Mosasaur was a whale-like, carnivorous mon-
ster, shorter and stouter than the preceding reptiles. Its
ponderous bones are wrecked along the old sea-coast, and
may be seen on the Alabama river projecting from the
limestone cliffs.

3. Strapping-turtles, six feet long and of many varieties,
lived in the salt water, as the now living species do in
fresh water.

4. Crocodiles were exceedingly abundant. Three-fourths
of all the bones found in the marl-pits are those of the
crocodile. These creatures swarmed along what is now
the river-front of Philadelphia, and peopled every pool
and lagoon on the ancient shores of Pennsylvania. Most
obstinate combats must have taken place between these
fierce crocodiles and the great snapping-turtles which
inhabited the same waters.

4. The Dinosaurs rivaled in size the elephants of our
day. Their aspect was strange and portentous; some
chiefly squatted, some leaped on their hind limbs like the
kangaroo, and some stalked on erect legs like great birds,
with small arms hanging uselessly by their sides, as with
bony visage they surveyed land and water from their
lofty elevation. Two of these saurians are noticeable :

(a.) The Hadrosaur was a massive, herbivorous reptile
about thirty feet long. The fossil remains have been
lately restored by Hawkins, and are set up in the Mu-
seum of Natural Sciences, Philadelphia. This monster
doubtless walked mainly on its hind legs, its knees

THE AGE OF REPTILES.

thrown upward and forward, and its huge tail trailing
behind. Its expression was that of a perpetual grin, as
its open mouth revealed several rows of shiny teeth
with which it cut the twigs on which it fed.
(b.) The Lcelaps was a powerful, carnivorous animal,
and the destructive enemy of the preceding smaller rep-
tiles. A full-grown specimen was probably twenty-three
feet in length. Its toes were long and slender like those
of a bird of prey. They were armed with flattened,
hooked claws, ten to twelve inches long, and adapted to
grabbing and tearing. Its teeth were curved, knife-
shape, saw-edged, and fitted like scissors for cutting.
The tail was long, rounded, and strong, and capable of
striking a blow or of throwing an enemy within reach
of the kick or grab of the terrible hind leg. It could
leap like the kangaroo, and probably captured its prey by
a few immense bounds.

Scenic Description.— Let us picture to our-
selves a landscape in this Mesozoic Age. It is an arm of
the ocean with broad, flat, muddy shores, at the bottom
of which is slowly gathering a sandy rock. The fog has
just lifted, and discloses a view of surpassing beauty. On
either hand the summits of the hills are crowned with
lordly pines, while the sloping land is overgrown with
palms and tropical trees. The shore is green with ferns
and reeds, whose tufted tassels nod in the gentle breeze.
Insects flit among the flowers of lily and palm, while
birds chirp in the cycad groves. It is the reign of
reptiles. On every hand they swarm — crawling, hopping,
stalking by the shore. The water is alive with them —
swimming, diving, and filling the air with an indescrib-

THE CRETACEOUS PERIOD. 193

able din. All day long enormous lizards crawl through
the forests, crushing the reed-like trees before them in
their headlong course, or plunge into the sea, leaving
behind a broad wake like a steamer ; while others, more
fearful still, spread their wings and riot in the air. Sail-
ing in and out among the shallow coves and bays of
the coast, the plesiosaur, arching its long neck, eagerly
watches a shoal of fish swimming near. But with quick
sharp strokes of its whale-like paddles, the huge ichthyo-
saur darts into view, and glares upon its prey with its
great bulging eye. Instantly the swan neck disappears
under the water, and the plesiosaur is hidden from its
rapacious foe— the terror of the Mesozoic seas. Mighty
dinosaurs, rivaling the elephant in size, stalk along the
shore or squat on the beach stupidly gazing on the scene,
save when the Maps, with fearful bounds, leaps among
their frightened herds, and tears them with his eagle-
claws. But night draws on apace. In the dim recesses
of the woods the pterodactyle — that winged dragon so
terrible to behold — sails slowly along on its broad, leath-
ern wings. As the shadows deepen, mighty sea-ser-
pents dart to-and-fro, battling with the rising billows;
that huge bloated frog — the labyrinthodon — jumps by
with great ungainly hops, while a tiny mammal,* the
first of its kind, flies frightened to the shelter of the
woods.

* This was the Dromatherium Sylvestre, the jaw-bone of which was discov-
ered by Emmons in North Carolina. It is the only mammal yet known to have
existed in America during the Mesozoic Age. In Europe, two or three insigni-
ficant ones of the lowest order have been discovered. No true bird remains
have been found on this continent, but in the quarries of Solenhofen they have
been scantily preserved. One, called the Arehaeopteryx, and Bird of Solenr
hofen. is very clearly identified, except the head.

194 THE AGE OF MAMMALS.

Mesozoic "Disturbances . — The Mesozoic Time,
like the Palaeozoic, was closed by mighty upheavals. As
Winchell beautifully says : " The ever-shrinking earth-
nucleus necessitated the ever-enlarging wrinkles of the
enveloping crust ; the furrows must deepen and the folds
must rise." The increasing pressure of the Atlantic and
Pacific oceans produced another upheaval of the land,
and another addition to the growing continent. This
was probably not a sudden convulsion, but a long-con^
tinued upward movement. By it, however, the condi-
tions of life were changed. All the Mesozoic types dis-
appeared—hardly any species survived the shock. A few
mammals, birds and flowering plants, types prophetic of
the Cenozoic Time, had appeared, but they all went down
in the shock. — Another cycle of geologic history is fin-
ished, another phase of life has swept across the slowly-
forming world, culminated and broken on the shore of
the past. The reign of reptiles is closed.

HENOZOIC |IME.

The Cenozoic or recent life of geologic history com-
prises only one age, that of mammals.

AGE OF MAMMALS, j2' Post-Tertiary Period,
(i. Tertiary Period.

General Characteristics. — The more striking
scenes of life hitherto have been confined to the water ;
they are now transferred to the land. Extensive bodies
of fresh water teem with fishes resembling pickerel,

THE AGE OF MAMMALS.

190

perch, eels, etc. Molluscan life takes on the types of
modern times— the bivalves increasing and the gastero-
pods taking the lead. Insects throng every element —
earth, air and water. Birds are also found in greater
numbers. It is emphatically, however, the age of mam-
mals. Quadrupeds of enormous bulk — many identical
with existing species — occupy the land. The herbs,
shrubs and trees — the flowers, fruits and grains — all that
can gladden the senses or satisfy the wants of man —
appear and confirm the harmony that always exists be-
tween organic and inorganic nature.

FIG. 89.

Map of Tertiary Period.

196 THE AGE OF MAMMALS.

Geography. — The great Mesozoic upheaval burst
asunder the Gulf Stream, which had sent the warm
waters of the tropics to the Arctic Ocean. On the south-
west it retired to nearly its present limits, but a long arm
reached up the Mississippi valley to the mouth of the
Ohio river (Fig. 89). On the north it broadened into
the great Tertiary Sea which extended through Nebraska
and the western part of Dacotah.* The Pacific Ocean
still held possession of the western coast, while the
Atlantic Ocean covered the southeastern border of the
continent, and the coral builders were yet at work upon
Florida.

TERTIARY PERIOD.

4. Sumter (S. C.) Epoch.

. 3. Yorktown (Va.) Epoch.
PERIOD. \ 2_ Alabama Epoch_

i. Lignitic Epoch.

In Europe, the divisions of the Tertiary Period are
Eocene (recent dawn), Miocene (less recent), and Pliocene

* At the close of the Mesozoic Age, Europe was still far from displaying the
configuration which it now presents. A map of the period would represent the
great basin of Paris (with the exception of a zone of chalk), the whole of Switzer-
land, the greater part of Spain and Italy, the whole of Belgium, Holland, Prussia,
Hungary, Wallachia, and northern Eussia, as one vast sheet of water. A band
of Jurassic rocks still connected France and England at Cherbourg. This dis-
appeared at a later period, and caused the separation of the British Islands from
what is now France. — Figuier.

t The name Tertiary is a relic of early geological science. When introduced,
it was preceded in the system of history by Primary and Secondary. The first
of these terms was thrown out when the crystalline rocks, so called, were
proved to belong to no particular age, though not without an ineffectual attempt
to substitute it for Paleozoic ; and the second, after use for a while under a re-
stricted signification, has given way to Mesozoic. Tertiary holds its place
simply because of the convenience of continuing an accepted name (Dana).
The term Quaternary, used in connection with the Post-Tertiary Period, had a
similar origin.

THE TERTIARY PERIOD. 197

(more recent). On this continent these terms do not
apply, and an American classification has been adopted.
In the Pliocene, most of the species are allied to existing
forms; in the Miocene, fewer are thus related; and in
the Eocene, we recognize only the dawn of modern forms.
The Lignitic and Alabama beds have been referred by
Dana and other prominent authorities to the Eocene,
the York town to the Miocene, and the Sumter to the
Pliocene.

The Marine Tertiary beds lie on the
Atlantic, Pacific, and Gulf borders,* and extend up the
Mississippi valley to the mouth of the Ohio river. Fresh
water Tertiary beds occur on the eastern slopes of the
Rocky Mountains and in the upper Missouri region.
There are no great continental strata, as in the Silurian
Age, but rather such a diversity as we find in formations
now in progress on the sea-coast, where the beds often
change in character within small distances. These
modern deposits give us the key to the ancient one
(See pp. 23 and 29.)

*" What are known as the Pine Barrens, in the southern States, is a belt of
country more than 1,700 miles long, and often 170 miles broad, stretching from
Richmond, along the Atlantic and Gulf coasts, to beyond the western line of
Louisiana, where the soil, derived from the decomposition of the newest
member of the Tertiary series, is sandy, and where the principal arborescent
form is the long-leaf pine. It is emphatically the "poor man's region." These
forests, while affording a valuable article of lumber, also yield pitch, tar, and
turpentine. On the Pacific slope the Tertiary rocks, which are referred to the
Miocene Group, appear to be coterminous with the Cretaceous. They enter into
the frame-work of the Coast Ranges, stretching from the Columbia to San Louis
Bay, and probably to Cape St. Lucas; and throughout the entire extent the
strata are upheaved, plicated, and metamorphosed, and, at frequent intervale,
invaded by igneous products. They repose in horizontal strata upon the foot-
hills of the Siorra, but are in a disturbed position where they fold around
Shasta'.— Foster's Mississippi Valley, published by Messrs. S. C. Griggs & (70M
Chicago.

19S THE AGE OF

J£tnds of ffiocfc. — The Tertiary beds consist of
sand, clay, marl, pebbles, etc. Near Charleston, S. C., are
extensive phosphate beds, rich in phosphate of lime, and
mined as a fertilizer. At St. Augustine, Fla., is a curious
rock, locally known as "coquina," composed of broken
shells, but cemented so as to make a good building stone.
The Eocene of the old world contains strata of NUAI-
MULITIC (nummus, a piece of money) limestone thousands
of miles in length and hundreds of feet in thickness. It
is so called because it is largely composed of a fossil*
having the shape of a coin. The most noted Pyramids
are built of this stone, and wagon-loads of the fossils, dis-
integrated by the weather, lie at their base.

Extensive beds of light bituminous coal (lignite) are
found scattered from Pike's Peak to the Arctic Ocean,

across Vie treeless regions
FIG. 90. west of the Missouri, and

thence into Oregon. The
wide distribution and con-
venient locality of these
Tertiary coals must ex-
ercise a vast influence in
facilitating communica-
(Nummuiites ataica). tions over the great deserts
of the west, and can but

be considered as a providential forecast of the wants
of man.

Fossils. — I. PLANTS. — The abundance of vegetable
remains proves the land to have been covered with an
exuberant flora. Leaves of oak, maple, poplar, hickory,

* The nummullite is a rhizopod, being the giant of that family. (See p. 100.)

THE tERTIAHY PERIOD. 199

cinnamon, fig, palm, and pine are abundant.* A leaf of a
fan-palm has been found on the Upper Missouri, that,
when entire, was probably twelve feet across (Dana).
Nuts are common in some localities, as at Brandon, Vt.
In the London basin a single collector gathered 25,000
specimens of fossil fruits representing five or six hundred
species. Many of them were products of aromatic and
spice groves, such as now flourish in Ceylon and the West
Indies. The extensive deposits of diatoms at Richmond,
Va., and Bilin, Germany, etc., which have been already
mentioned (page 48) are of this period.

II. AKIMALS. — Tertiary shells of over 3,000 species have
been found in America. They have the look and often-
times the freshness of modern specimens, as may be seen
in the accompanying cuts of Miocene Gasteropods, (See
Fig. 91.) In Colorado and Utah are shales containing
insects so well preserved that even the microscopic hairs
of the wings can oe detected (Denton). The first bee
made its appearance in the amber f of the Eocene, locked

* The earth had already its seasons, its spring and summer, its autumn and
winter, its seed-time and harvest, though neither sower nor reaper was there ;
the forests then, as now, dropped their thick carpet of leaves upon the ground in
the autumn, and in many localities they remain where they originally fell, with a
layer of soil between the successive layers of leaves — a leafy chronology, as it
were, by which we read the passage of the years which divided these deposits
from each other. Where the leaves have fallen singly on a clayey soil favorable
far receiving such impressions, they have daguerreotyped themselves with the
most wonderful accuracy ; and the trees of the Tertiaries are as well known to
us as are those of our own time. — Agassiz in Geological Sketches.

t See Fourteen Weeks in Chemistry, page 226. Amber has been found quite
abundant on the shores of the Baltic, washed out of the lignite beds by the
waves. Species of coniferous trees existed, from which gum or resin flowed,
and becoming fossilized, amber was the result. In flowing down the tree, in-
eecte, spiders, small crustaceans, and leaves were covered ; and thus we find
them preserved in the transparent amber. Over 800 species of insects, and 98
of trees and shrubs have been observed, besides numerous mosses, fungi, and
liverwort.— Denton in Our Planet.

FIG. 91. GASTEROPODS OF THE MIOCENE.

Pvrula reticulata.

Cancellaria reticulata.

Fusus exilis.

FIG. 92. GASTEROPODS OF THE MIOCENE.

Murex globosa. (Half natural size.) Galeodia Hodgii.

FIG. 93. ECHINODERMS OF THE MIOCENE.

Rosette, beneath.

FIG. 94.

Gonioclypeus subangulatus, E.

FIG. 95.

Scutella Newbernensis, E.
The " Lone Star of Texas.'

Echinus Ruffini.

THE AGE OF MAMMALS.

FIG. 96.

up hermetically in its gum-like covering—" an embalmed
corpse in a crystal coffin/' as Hugh Miller quaintly re-
marks. Broken wings of butterflies
also attest the presence of flowers.
Ants, crickets, grasshoppers, beetles,
and dragon-flies are so numerous that
some kinds seem to have afforded food
to the first mammals that appeared.
Fish existed in great abundance,
mostly allied to the modern perch
and salmon. Sharks' teeth have been
found six inches in length.

The bones of a species of whale
called the Zeuglodon (yoke-tooth), so
called from the shape of its teeth,
occur in great abundance scattered over the cotton lands
of the south. In Alabama they have been laid up in

FIG. 97.

Oxyrhina Desorii.
Shark's Tooth from N. C.

Zeuglodon's Tooth.

THE TERTIARY PERIOD. 203

walls for fences, or burned for lime. A single vertebra is
a load for a man to carry. The animal was about
seventy feet long.*

QUADKUPEDS, thick-skinned and ruminating mammals,
were the great feature of the Tertiary life.

European Quadrupeds. — Cuvier was the first to bring
to light the forms of these long-extinct animals. In the
Gypsum quarries, near Paris, bones were dug up in great

FIG. 98.

Scene in Paris Basin.
i. The Paleotherium. 2. The Anoplotherium. 3. The Xiphodon.

numbers, but they were disregarded, as they were thought
to be those of existing species, until the attention of this
great naturalist was directed to them. He gathered a
large quantity in a room, and commenced the work of
assorting and re-creating. "At the voice of comparative
anatomy every bone and fragment resumed its place."

* The restored skeleton of a Zeuglodon is on exhibition in Wood's Museum,
Chicago. It contains 118 vertebrae, and its head is six feet long. Prof. Winchell
pronounces it, for the most part, an accurate representation of this alligator-like
whale.

204

THE AGE OF MAMMALS.

(Cuvier.) He restored the animals, assigned them to
their classes, and investigated their habits.

The neighborhood seems to have been a gulf of the sea,
into which emptied several rivers. Animals inhabiting
the banks of these streams were borne down, and de-

FIG. 99.

View of the Bad Lands.

posited in the sediment which gathered at the mouth.
Among the quadrupeds the most conspicuous was the
Paleotherium (ancient wild beast), peaceful flocks of
which must have inhabited the plateau which environed
the ancient basin of Paris. It resembled the South
American tapir, but was as large as a horse.

American Quadrupeds. — On this continent similar dis-
coveries have been made in the Mauvaises Terres, or Bad
Lands of Dacotah. This region consists of immense beds
of clay cut out by rivers into winding channels, leaving

TH E TERTIARY PERIOD. 205

thousands of irregular columnar masses often one to two
hundred feet in height. So thickly is the surface studded
with these natural towers, that the traveler must thread
his way through deep, confined labyrinthine passages not
unlike the narrow, irregular streets and lanes of some
quaint old European town.* The soil is barren and arid.
It is a literal Golgotha — a place of bones. At every step
in this charnel-house the explorer treads upon the re-
mains of a former age. The clayey walls are built up
with broken skeletons. Hundreds of fossil turtles (see
Fig. 100) are strewn about, many weighing a ton each.
On every side are scattered bones strangely like the
familiar forms of to-day, but of unknown species and
unwonted combinations. Thus the Titanothere was
tapir-like, but had horns and was 8 feet high. The Din-
oceras resembled an elephant in size, but instead of a
trunk had three pairs of horns.

The Origin of this Region was, probably, as fol-
lows : The great Tertiary sea was at first salt, but receiv-

* These rocky piles, in their endless siiccession, assume the appearance of
massive artificial structures decked out with all the accessories of buttress and
turret, arched doorway and clustered shaft, pinnacle and finial and tapering
spire. On a nearer approach the illusion vanishes, and all the forms which fancy
has conjured are resolved into barren desolation. The bottom of the vale is an
earth of chalky whiteness, baked by the sun, and utterly destitute of vegetation.
The water which oozes out of the foundation-wall of the prairie is brackish and
unpalatable. In winter, the wind and snow rush through the lanes and corri-
dors of this city of the dead in eddying whirls, while the withered grasses and
the voiceless and motionless solitude, together with the relentless frost and
never-tiring storm, make the place the realization of utter bleakness and desola-
tion. In summer the scorching sun literally bakes the clays which have been
kneaded by the frosts and thaws of spring ; and the daring explorer of the scene
finds no tree nor shrub to shelter him from the fervid rays poured down from
above, and reflected from the white walls which tower around him, and the
whHe floor which almost blisters his feet — Sketches of Creation — Wlnchett.

THE AGE OF MAMMALS.

ing fresh water from the drainage of the adjacent land,
and having an outlet into the ocean, it gradually became
a brackish, and at last a fresh-water sea. As the conti-
nent was elevated, this great inland sea was drained in
part, and in time probably became broken up into a

FIG. ioo.

Testudo Oweni.

chain of fresh-water lakes.* The basin of one of these,
now constituting the Bad Lands, is thought by Hay den
to have covered an area of 150,000 square miles— five
times as great as that of Lake Superior. The shores of
these lakes during the Tertiary and Post-Tertiary Periods
were inhabited by the rhinoceros, elephant, camel, horse,
beaver, wild cat, wolf, and many quadrupeds, whose en-
tire species are now extinct. In these familiar haunts,

* It is not difficult, with the discoveries already made in Colorado, to call up
the country as it existed on the eastern side of the mountains about the close of
the Miocene Period. A long and wide lake covered the spot where Golden City
and Denver now stand, and stretched north and south for an immense distance.
Its banks were clad with forests of pines, palms, and gum-bearing trees. —Denton.

THE POST-TERTIARY PERIOD. 207

amid a semi-tropical vegetation, they lived and died.
Their remains, sinking in the soft mud, reveal to us
to-day the forms of Tertiary life.

PO ST-TERTI A RY PERIOD.

(Quaternary Epoch.)

^3. Terrace Epoch.

POST-TERTIARY PERIOD. -< 2. Champlain Epoch.
( i. Glacial Epoch.

i. GLACIAL EPOCH.

(Drift or Bowlder Period?)

The continent has been steadily growing through the
ages until now it has attained its full dimensions. It
would seem to be ready for man. It abounds in coal,
timber, water, game, and the domestic animals necessary
for man's use. We naturally expect his creation next,
and, almost unconsciously, look about for traces of his
presence. But God's plan is not yet complete. The next
period seems one of retrogression, and a superficial view
would lead one almost to despair of the result. We must
not, however, be impatient, but wait the slow development
of Nature's laws. The earth having passed the ordeal by
fire and water, now enters upon that by ice. The long
summer is over. For ages a tropical climate has pre-
vailed, and on the borders of the Arctic Ocean animals
have roamed and plants have flourished which now find
a home only beneath the burning sun of the Tropics.
Their reign is past. A tedious Arctic winter succeeds.
During its rigors life disappears, and half of the conti-
nent reverts to its primeval desolation. Let us uotico

THE AGE OF MAMMALS.

some of the traces of this wonderful change — this appar-
ent check in the world's progress.

1)rift. — This includes the loose un stratified* deposits
of clay, sand, gravel and stones familiar to all inhabit-
ants of the northern States. It does not extend south of
latitude 39° f nor west of the Rocky Mountains (Whii>
ney and Foster). In some places the Drift material forms
only a slight covering over the solid rock, while in others
it is piled up in hills and ridges.

BOWLDERS. — The stones are of all sizes, from small
cobble-stones up to great rock-masses. In Whitingham,
Vt, is a bowlder whose length is forty feet, and whose
estimated weight is 3,400 tons ; another in Bradford,
Mass., is 30 feet square. Plymouth Rock is a bowlder of
syenitic granite, ledges of which are to be seen near
Boston. The pedestal of the statue of Peter the Great
was hewn from a block of granite weighing 1,500 tons,
which was found in a neighboring marsh. Bowlders are
sometimes so nicely poised that they can be rocked by
the hand, although an immense force would be required
to dislodge them.

Bowlders are more or less rounded, as if water-worn,
and their structure and mineral composition are different
from those of the rocks on which they rest. They have
evidently been transported to the places they occupy.

* When the deposit is arranged in layers, it is termed Modified Drift. Mod-
ified Drift at many places forms knolls of a most picturesque description. On
account of their beauty, they are oftentimes chosen for burial places. Mt.
Hope at Rochester, and Woodlawn at Elmira, N. Y., Mt. Auburn at Cam-
bridge, and the cemeteries at Plymouth, Newburyport, and North Adams, Mass.,
are all delightfully located on sites of this formation.

t 39° is about the latitude of Washington, Cincinnati, St Louie, Kansas City,
Pike's Peak, and Sacramento City.

THE POST-TERTIARY PERIOD.

209

The "parent ledges " from which they were derived can
generally be found at the north of the locality— some*

FIG. lor.

View near Gloucester, Mass.

times at a distance of a few rods only, at others of
many miles. Long Island and Martha's Vineyard are
covered with rocks derived from the main-land. The
southern part of Rhode Island is strewn with iron ore
from Iron Hill (Cumberland, R. I.). On Hoosic Moun*
tain is a bowlder of 500 tons weight, which has been
carried from a ledge across an intervening valley 1,300
feet deep, and at the same time elevated 1,000 feet above
its source. Masses of native copper from Lake Superior
are scattered over Wisconsin, Michigan, and even Ohio
and Indiana. The streets of Cincinnati are paved with
stones quarried by the hand of Nature in the region of
the Upper Lakes (Winchell). Azoic rocks are found
on the western prairies, from 400 to 600 miles distant
from their homes, (Such bowlders are significantly

%10 THE AGE OF MAMMALS.

termed lost rocks* A bushel of pebble-stones gathered
in any northern State will often represent nearly every
geological formation found for hundreds of miles north
of that locality.

GLACIAL STRIDE. — A careful examination of many of
these bowlders shows us that they are covered with paral-
lel grooves (strice). These have obviously been caused
by the scraping of the bowlders on the solid rock, as if the
Drift material had been carried forward by an irresistible
force, since the "bed rock" (the rock in place) in the
regions covered by the Drift is polished and grooved in a
similar manner. These striae consist of long, straight,
parallel lines, — furrows a foot broad and several inches
deep, or scratches fine as a pin would make. The sur-
faces of hard rocks, as quartz, are often polished smooth
as glass, while the markings can be seen only with the
microscope. The general course is that in which the
bowlders have been carried, i. e., from north to south,f

* In New England, oftentimes the surface for many miles is covered with
these erratic blocks ; on the prairies, however, they are found only occasionally.
This may he caused by the different character of the rocks at the east and at the
west. While every location shows the intrusion of foreign material, the great
mass is made up by the destruction of neighboring rocks. The Silurian and
Devonian rocks of the Mississippi valley would naturally produce a soil far
different from that of the crystalline and metamorphic rocks of New England.
The agent which transported the rocks might have ground the softer class to an
impalpable powder, and left the other of a far coarser texture.

t "In general, these striae do not alter their course for any topographical
feature of the country. They cross valleys at every conceivable angle, and even
if the striae run in a valley for some distance, when the valley curves the striae
will leave it, and ascend hills and mountains even thousands of feet high. But
these striae are never found upon the south sides of mountains, unless for a part
of the way where the slope is small. Mt. Monadnoc, of New Hampshire, is an
illustration of these statements. It is a naked mass of mica schist, 3,250 feet
high, rising like a cone out of an undulating country. And from top to bottom
it has been scarified on its northern and western sides, indicated by striae run-
ning up the mountain, at first south-easterly, and at the top at S. 10' E. There
are deep furrows and other phenomena on the summit, and the striae extend a
short distance up the southern slope of the mountain."— Hitchcock.

THE POST-TERTIARY PERIOD.

varying generally not more than 50° east or west. There
are frequently two or more sets of striae, differing a little
in direction. At Stony Point, Lake Erie, the limestone

FIG. 102.

Bowlder Scratches.

lies exposed above the level of the water. The bed is
planed down smooth as a floor, and at one place the par-
allel grooves strikingly resemble the deep ruts produced
by a loaded wagon. On the Platte river there is a ledge
of limestone so regularly planed that, without further

THE AGti OF MAMMALS.

working, it can be used for caps and sills in houses. At
Marquette, on Lake Superior, there are surfaces as
uniform as if worked to a level and afterward rubbed
with sand-paper. Near the sea-shore at Portland, Maine,
the striae run parallel for great distances and then dis-
uppear in the water. Everywhere in the northern part
of the continent, up to a height of five or six thousand
feet above the level of the sea, where the bed-rock is
laid bare, it is found covered with these Drift-tracings.
We can best understand the cause of the Drift phenom-
ena by noticing similar cases now exhibited in Alpine
regions.

GLACIAL PHENOMENA. — The snow which falls on the
mountains of Switzerland, above the so-called snow
line, does not melt, but accumulates to a great thickness.
By its own weight it generally packs into a solid mass.
Thawing superficially by day, tiny streams of water per-
colate through, and convert it into the beautiful azure-
tinted ice, so much admired by tourists. Seas of ice
(mers cle glace] fill the spaces between the summits, while
from them, down every valley, pour rivers of ice, glaciers,
from 200 to 5,000 feet deep. These ice-streams, fed by
the snows above, extend downward until they are melted
by the summer sun in the valley below. They sometimes
plough irresistibly into the cultivated fields, so that a
person can, with one hand, touch the growing corn, and
with the other the descending ice-wall. The glacier ad-
vances down the mountain at the rate of from eight to
twelve inches per day. Frost, rain, hail, and avalanches
of snow are continually detaching from the mountain-
peaks masses of rock, which roll down upon the glacier.
If the ice were stationary these would merely gather in a

THE POST-TERTIARY PERIOD.

confused pile, but owing to the forward movement of the
glacier, they form along the outer edge a line of stones
which is termed a Moraine. When the rocks fall from
opposite mountains and on each side of the glacier, they
make two parallel trains which are called Lateral Mo-
raines (Fig. 103). At the foot of the glacier the debris
gathers in ridges, styled Termini Moraines.* In thi
way enormous blocks of stone have been carried many
miles. They are often found perched on points of the
Alps far above existing glaciers, or dispersed over distant
plains. Masses thus conveyed on the surface of the
glacier are little worn. Blocks, pebbles, etc., however,
which become frozen in the ice, are forced along in the
onward progress of the glacier, scoring the rock beneath
with parallel lines, and smoothing its surface as emery
polishes steel, while they are themselves rounded and
scratched in every direction, and even ground into im-
palpable powder. The glacier thus becomes a gigantic
rasp hundreds of feet thick, thousands wide, and miles
in length, scouring the rocks between and over which
it passes.

* " The masses of snow which hang upon the Alps during winter, the rain
which infiltrates between their beds during summer, the sudden action of tor-
rents of water, and more slowly, but yet more powerfully, the chemical affini-
ties, degrade, disintegrate, and decompose the hardest rocks. The debris thus
produced falls from the summits into the circles occupied by the glaciers with a
great crash, accompanied by frightful noises and great clouds of dust. Even in
the middle of summer I have seen these avalanches of stone precipitated from
the highest ridges of the Schreckhorn, forming upon the immaculate snow a
long black train, consisting of enormous blocks and an immense number of
smaller fragments. In the spring, a rapid thawing of the winter snows often
causes accidental 'torrents of extreme violence. If the melting is slow, water
insinuates itself into the smallest fissures of the rocks, freezes there, and rends
asunder the most refractory masses. The blocks detached from the mountains
are sometimes of gigantic dimensions ; we have found them sixty feet in
length, and those measuring thirty feet each way are by no means rare in the
Deux Mondes— Martin.

AGE OF MAMMALS.

Evidences of Former Glaciers. — Moraines,
erratic blocks, polished surfaces, striae, etc., become to
the geologist infallible signs of the former existence of
glaciers,* and enable him to follow them in their course
and fix their origin. One who is familiar with tracing
the furrows of this mighty ice-plow will recognize at once
where the large bowlders have hollowed out their deeper
gashes, where small pebbles have drawn their finer marks,
where the stones with angular edges have left their sharp
scratches, and where fine sand and gravel have rubbed
and smoothed the rocky surface, and left it polished as
if it came from the hand of the marble-worker.

Glaciers of Greenland. — Glacial phenomena are
displayed on the grandest scale in Greenland. On its
western coast is a glacier 1,200 miles long. It presents
to the voyager a perpendicular wall of ice 2,000 feet
high. A great glacial river, says Kane, seeking outlets
at every valley, rolling icy cataracts into the Atlantic and

* Some or all the marks above enumerated are observed in the Alps at great
heights above the present glaciers and far below their actual extremities ; also
in the great valley of Switzerland, fifty miles broad : and almost everywhere on
the Jura, a chain which lies to the north of this valley. The average height of
the Jura is about one-third that of the Alps, and it is now entirely destitute of
glaciers ; yet it presents almost everywhere similar moraines, and the same pol-
ished and grooved surfaces and water-worn cavities. The erratics, moreover,
which cover it present a phenomenon which has astonished and perplexed the
geologist for more than half a century. No conclusion can be more incontest-
able than that these angular blocks of granite, gneiss, and other crystalline for-
mations came from the Alps, and that they have been brought for a distance of
fifty miles and upward across one of the widest and deepest valleys in the
world ; so that they are now lodged on the hills and valleys of a chain composed
of limestone and other formations, altogether distinct from' those of the Alps.
Their great size and angularity, after a journey of so many leagues, have justly
excited wonder; for hundreds of them are as large as cottasres; and one in par-
ticular, composed of gneiss, celebrated under the name of Pierre & Bot, rests on
the side of a hill about 900 feet above the Lake of Neufchatel, and is no less than
forty feet in diameter.— Lyett.

TH£! POST-TERTIARY PERIOD.

the Greenland seas, and at last reaching the northern
limit of the land which has borne it up, pours a mighty
frozen torrent into Arctic space. Unlike the Alpine
glaciers, which melt in the warm valleys below, this
empties into the ocean, and vast masses becoming de-
tached, are floated away, to be dissolved in the milder
water of southern seas. Thousands of these icebergs
throng the northern ocean, freighted with debris to be
deposited on the sea-bottom of lower latitudes.* Could
we examine the track of these ice-rafts, we should doubt-
less find striae cut in the polished rocks, and blocks de-
posited in long trains where the bergs had struck,
scraped along by their enormous momentum and at
last stranded.

We are now prepared to understand the meaning of
the Drift phenomena.

Origin of the 3)rift. — The Arctic regions are
elevated, f The climate of the whole continent feels the
change. The cold creeps down every valley. Each
northern blast brings a frost. The verdure of forest
and plain withers and falls. The sun loses a part of
its heat. The sea becomes cold. Tertiary life perishes

* Describing Cape James Kent, Kane says : "As I looked over this ice-belt,
losing itself in the far distance, and covered with millions of tons of rubbish-
greenstones, limestones, chlorite slates, rounded and irregular, massive and
ground to powder— its importance as a geological agent in the transportation of
Drift struck me with great force. Its whole substance was covered with these
contributions from the shore ; and farther to the south, upon the now frozen
waters of Marshall Bay, I could recognize raft after raft from last year's ice-belt,
which had been caught up by the winter, each one laden with its heavy freight
of foreign material."— Arctic Expedition.

t It is proper to remark that, while all geologists agree as to the temperature
of this period, all do not accept the theory given above as to the cause of the
cold. Many different opinions are advanced. The above is supported by Dana,
Winchell, aad many prominent geologists. (Sea note in QUESTIONS, p. 272.)

218 TEE AGE Of MAMMALS.

in this frigid temperature. Arctic vegetation covers the
land where tropical flowers have so lately bloomed in
beauty. The musk-ox and the reindeer roam the south
of Europe where, in modern times, are to grow the olive
and the vine.* New species of animals spring into being,
clothed with a raiment of wool to protect them from the
rigors of the climate, and furnished with teeth of a
peculiar complexity, to enable them to browse on the new
vegetation. Rivers are stopped and turned to ice. Snow
gathers in the wintry air, and wraps in its mantle of
white all the desolation that has been wrought. Glaciers,
born in the icy north, invade the land. Sullenly they
move southward, along every great river valley, f plough-
ing the rock, paring down acclivities, J filling up ancient

* In the Drift are found the musk-ox, the reindeer, the walrus, the seal, and
many kinds of shells characteristic of the Arctic regions. The northernmost
part of Norway and Sweden is at this day the southern limit of the reindeer in
Europe ; but their fossil remains are found in large quantities in the Drift ahout
the neighborhood of Paris, and quite recently they have been traced even to the
foot of the Pyrenees. Side by side with the remains of the reindeer are found
those of the European marmot, whose present home is in the mountains, about
6,000 feet above the level of the sea.— Agassiz's Geological Sketches.

t The Connecticut Valley seems to have had an independent glacier, as the
striae are parallel with the general course of the river; the Mohawk another; the
Hudson a third one ; and traces of many smaller ones are being discovered.

% The current view that all the Drift or soil of the northern regions has been
produced by glaciers breaking up and grinding to pieces solid rocks, is opposed
by Bnrbank. In extensive observations at the South, below the line of the
Drift, he found the material of rocks apparently decomposed in places to the
depth of 25 or 30 feet. Contrasting with this the very small amount of disintegra-
tion which has taken place among similar rocks now exposed to the surface in
the same regions, he concludes that the time which has elapsed since the Drift
Period must be very short compared to the ages during which these solid rocks
were undergoing decomposition by chemical and atmospheric agencies ; that the
immense amount of material constituti-ng the Drift of eastern New England can
be accounted for only by supposing that the rocks were, before the Glacial Period,
decomposed and disintegrated to a great depth ; and that while, of course, the
glaciers wore and ground down the solid rocks, yet their chief action was to
carry forward and commingle the materials already disintegrated.

THE P OSTrTERTIARY PERIOD

river-channels,* burying forests under masses of debris,
scoring and polishing the surface, grinding up the stones
into soil, and strewing rocks, gravel, and sand over south-
ern fields. Beaching the coast of New England, they fringe
the ocean with an ice-wall for hundreds of miles. Mighty
icebergs, breaking loose, float southward, .and. grinding
their way through river-channel and strait, deposit their
rocky burdens in long trains over the sea-bottom, f or,
grounding on its shore, drop them in promiscuous piles.

II. CHAMPLAIN AND TERRACE EPOCHS.

^Depression of the Continent (CHAMPLAIN
EPOCH). — The epoch of Arctic elevation ceases. The
northern regions descend toward their former level.
Again the continent feels a change. A geologic spring-

* There is proof of the existence of rivers in different channels from the
present. At the Whirlpool, on the west bank of the gorge, three miles below
Niagara Falls, there is a deep ravine filled w\th gravel and sand. This old chan-
nel can be traced to Lake Ontario, four miles west of the present mouth of the
river, and must have been the ancient bed. During the Glacial Epoch, the
mighty ice-plow pared off the ridge, and filled the ravine with Drift materials,
so that the river was forced to seek a new route, and since then has worn away
the present tremendous gorge between Queenstown and the Falls. In boring
for oil, and in excavating for railroads, such ancient river-channels, now filled
with Drift, are frequently found.

" In excavating one of the canals for supplying the mills of Lowell, the old
channel of the Merrimack was found under the Drift and alluvium, half a mile
from the present bed of the river.11 — L. 8. Burbank.

t "There is one of these trains in Berkshire county, Mass. The moun-
tains from which the angular blocks of hard talcose slate have been torn
off, lies in Canaan, N. Y. ; and from thence they lie in trains, running for a
few miles S. 56° E., and then changing to S. 34° E., and extending yet further,
making in the whole distance not less than fifteen or twenty miles ; at least one
of them extends that distance, passing obliquely over mountain ridges some
600 or 800 feet high. Its width is not more than thirty or forty rods. The blocks
are of all sizes, from two or three feet in diameter to those containing 16,000
cubic feet, and weighing nearly 1,400 tons, and in some places almost cover the
surface of the common Drift, and are not mixed with \V~HUchcock.

THE AGE OF MAMMALS.

time has come. The fetters of winter fall off. The glacier
feels the touch of heat, and myriad streams leap gladly

FIG. 104.

Stream issuing from a Glacier.

forth. The snow-fields disappear. Torrents of water,
hastening to the ocean, deluge the continent. They cover
the southern valleys with fine sediment, the debris of the

THE POST-TERTIARY PERIOD.

glacier, and strew pebbles from the Appalachian to the
very border of the Gulf* (Wmchell). A genial warmth
pervades the air. Vegetation springs to life. The de-
pression of the land still continues. The ocean covers
a part of Maine. The Kiver St. Lawrence and Lake
Champlain become arms of the sea, tenanted by seals
and whales. The valleys are filled with broad, deep,
majestic rivers, whose waters, flowing to the sea, dig
deep channels, open new routes to the ocean, plough
through mountain-ridges, sort and sift the Drift debris,
arranging it in layers, and forming alluvial deposits of a
great thickness. In many parts of the northern States,
only the loftiest mountains emerge above the engulf-
ing waters. Billows roll where birds sang and flowers
bloomed. The land gained during all these long ages of
geological history seems lost again. The ocean triumphs,
and once more the Gulf joins its waters with the Arctic
Ocean.

JFlevation of the Continent (TERRACE EPOCH).
— Slowly the continent rises from its last baptism. Be-
fore reaching its former level it stops. The rivers dig
deeper channels in the soft alluvial deposit of the valleys,
and leave their former banks far up on hill-sides to mark
their submersion during the Champlain Epoch. The
lakes retire to smaller limits and form new beaches like
the old they have deserted. The ocean yields the sea-
coast, where it has so recently dashed in eager conquest,
and the land it has just reclaimed, and sullenly retreats.

* There are no "cobble-stones" in the southern States. The streams do not
eeem to have had sufficient force to carry the coarse material of the Drift. Thus
the sediment naturally becomes finer toward the south, and coarser north.

THE AGE OF MA MM A LS.

There are several pauses of this kind in the upward
progress of the continent.* At each stage the retiring
waters toy with the sand and gravel, arrange them in
beds, spread the alluvial soil upon the muddy bottom,
and put the finishing strokes to the work of fitting the
continent for man's use.

^Proofs of these Oscillations.— -Over the entire
continent we find in the river valleys, overlying the true
Drift, alluvial deposits reaching far above the present

FIG. 105.

Terraces on Connecticut River, south of Hanover, N. H. (Dana).

* The author repeats in this revision the statement made in the first edition
t.iat the current theory of these extreme oscillations of the continent seems to
him a purely artificial one. Places have been too hastily accepted as sea-beaches.
The terraces can be mainly, perhaps entirely accounted for by the damming up
of the valleys by drift material and the gradual wearing, sometimes sudden
bursting of these barriers. Streams running along the edges of the valleys when
the riven* were at a high level, may have produced the pot-holes and other phe-
nomena.

THE POST-TERTIARY PERIOD.

river bods. Looking up or down the banks of almost any
principal river, one can trace horizontal lines, marking
one or more terraces indicating the higher level of the
stream in former times.* Many villages owe the beauty
of their sites to these natural terraces. At a distance
from the present shore of lakes, we find beaches of sand
and gravel similar to those now existing on the borders
of the lakes, and, in general, parallel with them. There
are several of these on the south shore of Lake Erie ; one
extending for many miles is locally known as the " Ridge
Road." At Mackinac there are three of these stair-like
ridges, the highest 100 feet above the present wrater-level.t
Remains of whales and seals have been found at Mon-
treal, and the skeleton of a whale has been dug up on the
borders of Lake Champlain, sixty feet above its present
level. Near Brooklyn a sea-beach exists 100 feet above
the ocean. Along the River St. Lawrence, and in the
Champlain and Hudson valleys, there are deposits termed
" Champlain Clays," containing marine shells. They are
found over 500 feet above the ocean. It is evident that

* I counted to-day forty-one distinct ledges or shelves of terrace embraced
between our water-line and the syenitic ridges through which Mary River forces
itself. These shelves, though sometimes merged into each other, presented dis-
tinct and recognizable embankments or escarps of elevation. Their surfaces
were at a nearly uniform inclination of descent of 5°, and their breadth either
12, 24, 36, or some other multiple of twelve paces. This imposing series of
ledges carried you in forty-one gigantic steps to an elevation of 480 feet ; and as
the first rudiments of these ancient beaches left the granite which had once
formed the barrier sea-coast, you could trace the passing from Drift-strewn rocky
barricades to clearly-defined and gracefully curved shelves of shingle and
pebbles. T have studies of these terraced beaches at various points on the
northern coast of Greenland. They are more imposing and on a larger scale
than those of Wellington Channel, which are now regarded by geologists as in-
dicative of secular uplift of coast. — Kane's Arctic Explorations.

t When the lake stood at this level, it is probable that the water poured in
floods down the Illinois River valley, swelling it to a mighty stream. Traces of
its former grandeur are abundant far above its present banks.

THE AGE OF MAMMALS.

the banks exhibiting these remains were ancient sea-
beaches, and that the ocean level has since sunk and the
land risen.1*

Fossils of the Tost - Tertiary Teriod. — This
is the current era of geologic history. The record no
longer lies deep in the solid rock. We find it in the

* The most distinct beaches occur below 1,200 feet above the ocean level, A
very fine beach, however, is found on the west side of the Green Mountains, in
West Hancock, Vt., 2,196 feet high. Others are found in Peru, Mass., 2,022
feet ; at the Franconia Notch of the White Mountains, 2,665 feet , and at the
Notch of the White Mountains (Gibb's Hotel), 2,020 feet. Upon comparing to-
gether the heights of beaches in different parts of New England, we find a num-
ber of them having essentially the same elevation ; thus showing that they were
formed contemporaneously. For example, there are beaches in Ashfield and
Shutesbury, Mass. ; in Norwich, Corinth, Elmore, Hardwick, and Brownington,
Vt., each 1,200 feet above the ocean, and the most remote are nearly 200 miles
apart.— Hitchcock's Elementary Geology,

Page, in •' Chips and Chapters," referring to the raised beaches and submarine
forests of Great Britain, remarks substantially as follows : From 120 feet down
to the present sea-level we have a series of well-marked shore-lines— 120, 63, 40,
25, and 12 feet— marking a succession of uprises, all clearly pre-historic, if we
except the last, which indicates no very high antiquity. Every successive uplift,
while it increased the dimensions of the British Islands, also decreased the
general temperature of the country in the proportion of 1° F. for every 250 feet
of uprise or nearly. These -raised beaches are not all alike well marked and
decided, owing partly to the nature of the rocks into which they have been re-
spectively cut, and partly to the length of time at which the sea stood at these
respective levels. The lowest or twelve-feet beach is generally marked by ter-
races of recent shells and gravel. Though the latest of British-raised beaches,
this uprise must have taken place long antecedent to history ; and there is not,
so far as we are aware, any certain evidence either of upheaval or depression
since the time of the Romans, although certain misinterpreted appearances have
led some observers to an opposite conclusion. Any remains found in the caves
of the twelve-feet beach are savage and pre-Celtic, showing that the uprise had
taken place before (perhaps long before) the occupation of these primitive inhab-
itants. The twenty-five-feet beach is perhaps the most striking— stretching for
miles in unbroken continuity, composed in many districts of recent shells and
gravel, frequently backed by old caverned cliffs, and forming the level site for
most of our modern sea-ports and fashionable watering-places. The sixty-three-
feet beach is also well defined on many tracts of the seaboard, but its once over-
hanging cliffs have been obliterated by the tear and wear of the elements, its
shells and exuviae dissolved and destroyed, and its gravel beds now covered by
soil and greensward. Of the higher beaches little is known with precision, or
accuracy.

THE POST-TERTIARY PERIOD. 226

marls and sediment of filled - up lakes ; in beds of
sand and clay ; in the alluvial deposits of rivers ; in the
growth of peat-bogs and morasses ; in the deep, muddy
accumulations of swamps ; in the stalagmites of fissures
and caverns, and in the ice of Arctic regions. The
plant-remains — willow, hazel, fir, beech, and oak— are
familiar to those who now live in the same latitudes.
The fresh-water shells are identical with those which
throng the neighboring ponds. The marine fossils —
oysters, clams, mussels, etc. — cannot be distinguished
from those which inhabit the surrounding ocean. When,
however, we turn to the land animals, the change, prob-
ably through the instrumentality of man, becomes more
apparent. The quadrupeds, as in the Tertiary Period,
take the precedence, and attract our attention by their
enormous bulk. We shall describe the following : the
mammoth, mastodon, megatherium, glyptodon, Irish elk,
cave-bear, and hyena.

I. THE MAMMOTH, or fossil elephant, was about one-
third larger than any known to modern times. A tooth, in
the Ward cabinet, Eochester, weighs fourteen pounds. This
animal wandered in great herds over England, thence to
Siberia, and across Behring's Straits into North America.
Its remains are very abundant.* Over 2,000 molar-teeth

* In 1663, Otto von Guericke, the illustrious inventor of the air-pump, wit-
nessed the discovery of the bones of an elephant buried in the shelly limestone,
or muschelkalk. Along with it were found its enormous tusks, which should
have sufficed to establish its zoological origin. Nevertheless they were taken
for horns, and the illustrious Leibnitz composed, out of the remains, a strange
animal, carrying a horn in the middle of its forehead, and in each jaw a dozen
molar-teeth a foot long. Having fabricated this fantastic animal, Leibnitz
named it also ; he called it the fossil unicorn,. For over thirty years the uni-
corn of Leibnitz was universally accepted throughout Germany, and nothing
less than the discovery of the entire skeleton of the mammoth could change the

THE AGE OF MAMMALS.

were found in a few years by the fishermen of the little
village of Happisburg. The islands in the sea north of

FIG. 106.

The Mammoth or Fossil Elephant.

THE POST-TERTIARY PERIOD.

Siberia are but conglomerations of sand, ice, and the
tusks and teeth of elephants. During every storm, the
waves wash loose and cast ashore this fossil ivory, which
becomes a profitable article of commerce. Single tusks
are found weighing over 200 pounds. In 1844, 16,000
pounds are said to have been sold at St. Petersburg,
The ivory thus obtained has been exported to China for
five centuries, and yet the supply seems undiminished.
The colossal size of these remains has given rise, among
the Tartars, to a curious legend. They were believed to
belong to an enormous animal — an elephantine mouse —
which lived underground, like the mole, and which in-
stantly perished when exposed to the least ray of sun or
moon.

In 1799, a fisherman discovered among the icebergs on
the banks of the Lena, an odd-shaped block of ice. Two
years after, he found the tusks and flank of a mammoth
protruding from it, and in five years the entire body be-
came disentangled, and fell upon the sand. He removed
the tusks and sold them. Two years subsequent, Mr.
Adams, of the St. Petersburg Academy, heard of the dis-
covery, and visited the spot. The people of the neigh-
borhood had cut off pieces of the flesh for their dogs, and
wild beasts had mangled it, but the skeleton was nearly
entire. The skin yet covered the head ; one of the ears,
well preserved, was furnished with a tuft of hair; the
neck had a flowing mane ; and the body retained scat-

popular opinion, and then not without a keen controversy. Tn 1700, a veritable
cemetery of elephants was discovered near the banks of the Necker Eiver, in
Wurtemberg. Not less than sixty tusks were exhumed. As a curious instance
of the superstition of the times, the fact may be mentioned that the court
physician possessed himself of the fragments which were left, to aid him in com-
bating fever and colic 1 Chinese apothecaries now use similar remedies.

THE AGE OF MAMMALS.

tered tufts of reddish wool and black hair. Mr. Adams
collected the bones, repurchased the tusks — which were
more than nine feet long — and sold this unique specimen
to the Emperor of Russia for $6,000.

2. THE MASTODON resembled the modern elephant, but
had, in general, a longer body and more massive limbs.

FIG. 107.

The Mastodon.

When discovered, Buffon called this animal the Elephant
of the Ohio. A single tooth, however, is sufficient to dis-
tinguish its remains. The grinding surface of a masto-
don's tooth is covered with conical projections — whence
the name of the animal— while that of the elephant is
flat. Teeth have been dug up weighing seventeen pounds
each, and tusks fourteen feet in length. Six skeletons

TSJS POST-TERTIARY PERIOD.

were found in Warren county, N. J., by a farmer digging
in a bog. Within the ribs of one of them, being evidently
the contents of the stomach, were seven bushels of vege-
table matter, which, on microscopic examination, proved
to consist of cedar twigs, which probably formed the
animal's last supper. Similar discoveries, and also the
form of the teeth, prove that its food was roots, small
branches, leaves, grass, etc. The mastodon was once
comrnon in the United States, and probably wandered
in herds over all the country west of the Connecticut
River.

3. THE MEGATHERIUM * (monstrous beast), at first
sight seems the most ill-formed creature we have yet
considered. We shall, however, find its structure full of
harmony and adaptation. It was simply a huge sloth of
the size of an elephant. Like the sloth it fed on leaves,
and possibly like the ant-eater, it burrowed deep in the
earth. Its fore-feet were each three feet long and a foot
broad, and were furnished with gigantic claws. Its tail
was two feet in diameter, and must have assisted in
supporting its huge body, as it tore down trees for its
food, while it constituted also a powerful means of de-
fence. Its massive proportions and clumsy form rendered
it extremely slow in its movements, but there was no
need of rapid locomotion in an animal that merely bur-
rowed for roots or browsed for leaves in a tropical forest ;
neither was there necessity for flight, when its most dan-
gerous foe, the crocodile, could be destroyed by a single
blow from its gigantic tail. Thus this mighty creature

* The megatherium is shown in Fig. Ill, on the right hand ; the glyptodon in
front at the center, the mylodon just back holding on to a tree, and the masto-
don at the left and in the rear.

THE AGE OF MAMMALS.

lived peaceful and respected in spite of its apparently
unwieldy structure.*

4. THE GLYPTODON (sculptured tooth) was a mammal
clad in the shell of a turtle. This defensive armor mea-
sured sometimes eleven feet in length, and weighed 1,000
pounds.

FIG. 108.

Glyptodon clavipes.

5. THE IRISH ELK was a magnificent and imposing
animal. Its antlers were often ten feet long, and spread,
from one tip to the other, a distance of three or four
yards.

6. THE CAVE BEAR was the most formidable of the
ancient flesh -eating animals.

It attained the size of a large horse. Some of the

* During the dry season a hunter discovered, on the banks of the River
Salado, S. A., what appeared to be the trunk of a tree. Throwing his lasso over
it, with the help of a comrade he drew it upon the bank. It proved to be an
enormous bone five feet through; the pelvis of what has since been happily
styled the megatherium. To the countryman the bone appeared useless. It
did not make half as good a seat as a bullock's skull— the arm-chair of
the pampas. Finally this, with other bones, was sent as a curiosity to the
owner of the land on which they were discovered. Sir W. Parish found them
here, dug out others, and forwarded them to England. From these remains the
casts now in Boston, Amherst, etc., were made.— Denton in " Our Planet."

THE POST-TERTIARY PERIOD.

231

skeletons are ten feet long and six feet high. The ani-
mal is so named because it dragged its prey into caves,
where the remains of a large number of antediluvian
repasts are found buried in the stalactites which have

FIG. 109.

The Irish Elk.

since accumulated on the floor. In the celebrated cave
at G-aylenreuth, portions of the skeletons of 800 cave-
bears have been identified.

AGE OF MAMMALS.

7. THE HYENA was very abundant in England. The
bones of seventy-five have been discovered in a single
cavern. The cave at Kirkdale, England,* is noted as an

FIG. no.

"In the summer of 1821, some workmen employed in quarrying stone upon
the slope of a limestone hill at Kirkrlale, in Yorkshire, came accidentally upon
the mouth of a cavern. Overgrown with grass and hushes, the month of
this cave in the hill-side had been effectually closed against all intruders, and

iff

THE POST-TERTIARY PERIOD. 235

ancient haunt of these animals. " The stalagmitic de-
posit in this cavern, with its projecting bones/' says
Buckland, " looks like a pigeon-pie with pigeon's legs
sticking through the crust."

In Fig. 110, a cave-bear is seen sitting at the mouth of
its den, watching the bones of an elephant, while, above,
a hyena waits the proper moment to dispute possession
with its formidable rival.

its existence had never been suspected. The hole was just large enough to admit
a man on his hands and knees, and led into a low broad cavern, with branches
opening out from it — some of which have not yet been explored. The whole
floor was strewn with hundreds of bones, like a huge dog-kennel. The workmen
wondered a little at their discovery, but, remembering that there had been a
murrain among the cattle in that region some years before, concluded that these
must be the bones of cattle which then died in great numbers ; and having thus
satisfactorily settled the matter, threw out the bones on the road with the lime-
stone. A gentleman, living near, preserved them ; and in a few months, Dr.
Buckland, the great English geologist, visited Kirkdale, and examined its strange
contents, which proved indeed stranger than any one had imagined ; for many of
these remains belonged to animals never before found in England. The bones of
hyenas, tigers, elephants, rhinoceroses, and hippopotamuses were mingled with
those of deer, bears, wolves, foxes, and many smaller creatures. The bones
were gnawed, and many were broken, evidently not by natural decay, but as if
snapped violently apart. After a complete investigation, Dr. B. convinced him-
self, and proved to the satisfaction of all scientific men, that the cave had been a
den of hyenas at a time when these animals, as well as tigers, elephants,
etc., existed in England in as great numbers as they now do in the wildest parts
of tropical Asia or Africa. The narrow entrance to the cave still retains the
marks of grease and hair, such as are seen on the bars of a cage in a menagerie,
against which the imprisoned animals constantly rub themselves, and there
were similar marks on the floor and walls. The hjrenas were evidently the
lords of this ancient cavern, and the other animals their unwilling guests ; for
the remains of the latter had been most gnawed, broken, and mangled ; and the
head of an enormous hyena, with gigantic fangs complete, testified to their great
size and power. Some of the animals, such as the elephants, rhinoceroses, etc.,
could not have been brought into the cave without being first killed and torn
to pieces. But their gnawed and broken bones attest that they were de-
voured like the rest; and probably the hyenas then had the same propensity
which characterizes those of our own time — to tear in pieces the body of any
dead animal, and carry it to their den to feed upon it apart." (Agassiz.)— A de-
tailed account of this investigation, etc., may be found in " Reliquiae Diluvi-
anse," by Dr. Buckland.

236

THE AGE OF MAMMALS.

. — /• Gtaciat J?poch on the (Pacific
Coctst. — California shows no traces of northern Drift.*
The Rocky Mountains probably constituted a sufficient
barrier against the advancing glacier that overwhelmed
so large a portion of the continent. Yet no section ex-
hibits more frequent signs of glacial action. The glaciers
were, however, confined to the elevated regions of the
mountains, as the conspicuous moraines, stria?, etc., abun-
dantly prove. Swift torrents sweeping down the slopes
of the mountain ranges denuded extensive regions and

FIG. 112.

Canon of Grai.d Rivei.

deposited vast quantities of Drift-material. This erosive
action doubtless broke up the auriferous rocks and as-

* Whitney in Proc. Cal. Acad. Nat. Sci. Foster says the same remark holds
true throughout Oregon.

THE POST-TERTIARY PERIOD.

sorted the materials of the rich gold-fields of California.
The great cations (kan'-yuns) of the Colorado and other
western rivers are believed "by Newberry to have been
worn out during this period. They are. gorges cut in the
solid rock, sometimes to the depth of a mile. For days
the adventurer may travel along the brink of such a gulf,
unable to cross or to descend to the water which winds
along so far below, at the bottom of the appalling chasm.

2 . Fhe £oess (Lo-ess, from the German I'dsz, loam).
— The alluvial deposits along the banks of rivers are
generally composed of coarse materials at the lowest por-
tions, and fine loam (silt) in the higher. Where the
current is strongest, coarse gravel is borne along, and
where weakest, only sand or mud. A thin film of this
fine sediment is spread during floods over wide areas on
either bank of the stream. The well-known deposits of
the River Nile, to which Egypt owes its fertility, are of
this character. The aggregate during a century is said
rarely to exceed five inches, though in all it has attained
a vast thickness.

Along the valley of the Rhine similar deposits of loam
have taken place to a depth of many hundred feet. The
color is of a yellowish gray, the structure very homoge-
neous, and the composition like that of the Nile. Shells
most perfectly preserved, whose fragility is too great to
endure the rushing of a stream of water, are quite abun-
dant.

3. Bhtff Formation.— This Loess or "Bluff For-
mation " (Swallow) extends to a great distance along the
lower Missouri, and often lines its branching rivers. It is.

238 THE AGE OF MAMMALS.

very conspicuous at Sioux City, Council Bluffs, etc. On
the Mississippi it reaches from the junction of the Mis-
souri to the delta, forming in the State of Mississippi a
belt ten or fifteen miles wide, and often seventy feet deep
(Hilgard). The color is a buff, and its composition a
siliceous loam. The shells belong to existing species,
while the remains of mammoth, horse, lion, musk-ox,
etc., are of extinct species. We thence conclude that the
physical changes which resulted in the destruction of the
land animals did not extend to the inhabitants of fresh
water. Foster thinks that the formation is a lacustrian
one, and that when it was deposited, the land was de-
pressed a couple of hundred feet below its present level.

4 . Sand 1)unes* are hills of sand heaped up along
the shore. They are formed by sand drifted inland by
the wind, as snow is piled in drifts. The sand is driven
with such force as to smooth the surface even of quartz
rocks, and to wear holes in window-glass. The sand-
dunes of Cape Cod, Long Island shore, Lake Michigan,
etc., are conspicuous features of the landscape. Some-
times long, narrow sand-ridges, or Osars, extend back
from the shore for miles.

«J. The Mosaic Account states that on the fifth
day the waters brought forth abundantly the moving

* On the east side of Cape Cod, clearly marked in many places on the beach
between Provincetown and Truro, the former shore-line, of the west side may be
distinctly traced. The whole mass of sand forming that part of the cape has
been carried over westward into the bay. This movement is still going on, and
threatens to destroy the harbor of Provincetown. Parties of men have therefore
been employed by the United States government to set out beach-grass along
the coast. This, by the extension and interlacing of its fibrous roots, tends to
hold the sand in place.— Burbank.

THE POST-TERTIARY PERIOD.

creature that hath life, the fowl that flies above the earth,
and great whales. The sixth day was characterized by
two works — the creation of mammals, and lastly of man,
to be the lord of all created things.

Geology gives us the same general outline. In the
Palaeozoic Age, the seas swarmed with life. In the Meso-
zoic Age, birds appeared, while reptiles (styled, in popular
language, great whales or sea-monsters, as the word may
be translated) became the dominant life. In the dawn
of the Cenozoic, mammals of enormous size and in pro-
digious numbers covered the earth; while at the close,
Man appeared to crown the creative work.

Scenic Description.— This glimpse of Tertiary
times presents a scene of sylvan beauty. Before us
is a broad meadow carpeted with grass and blooming
flowers, while behind are mountains clad in forests of
familiar trees. In the foreground is a lake stretching
away in the distance far as the eye can reach, its waves
sparkling in the noontide sun. Snipes make their retreat
among the reeds which line the low marshy shore ; sea-
gulls skim the water ; owls hide themselves in the trunks
of old cavernous trees ; gigantic buzzards hover threaten-
ingly in the air, poised for prey ; great turtles crawl up
the bank; heavy crocodiles drag their unwieldy bodies
through the high marshy grass ; and a huge rhinoceros
wallows, grunting, in the mud. Over the plain gallops
a troop of wild horses ; foxes scamper through the bushes ;
and flocks of birds sing in the branches of the willows
that border a neighboring brook. Everywhere wander
great, unwieldy quadrupeds. Here is a solitary megathe-
rium— a gigantic sloth — standing on his massive hind-

240 THE AGE OF MAMMALS.

legs, and propped up by his huge tail, which makes a
secure tripod support See, he slowly reaches out his
muscular arms, draws down branches and young trees,
and lazily feeds on their tender foliage. Yonder is a herd
of mammoths with long curved tusks, broad flapping
leathern ears, large as a blacksmith's apron, and legs like
fleshy pillars. Now they feed along the bank, now they
trumpet shrilly to their companions in the forest, whose
responses sound like distant thunder, and now they go
crashing through the woods, tearing down trees for sport,
and leaving the limbs strewn over the ground, as if a
hurricane had passed. Fierce beasts abound. A drove
of wild oxen of colossal strength, maned and shaggy,
feed over the meadow, and troops of hyenas prowl about,
waging relentless war on all weaker tribes. Hark ! the
yelping of dogs! A pack of hounds out on a hunt. The
herd of wild horses catch the dreaded sound, snort with
fear, toss their manes, and go flying off like the wind,
with their gaunt pursuers in full chase. Scarcely have
they disappeared when a drove of camels stalk deliberately
down to the water's edge, and while they drink (as only
camels can), a troop of monkeys, chattering in the
branches overhead, with solemn grimaces, mock the grav-
ity of their slow, awkward movements.

Geology, which is the story of the rocks, finds its climax in
History, which is the story of Man.

The Coming of Jlfan . — We have no means of de-
ciding the exact time when the human race first appeared
on the earth. The most scientific man is unable to name
centuries or years with any degree of accuracy in connec-
tion with any geological event. In the loam (Loess),
peat-bog and cave-earth of the Post-Tertiary Period we
first find rude stone implements, tree canoes, and the
embers of the fire which man alone can kindle or sus-
tain. Side by side with these are the remains of the
mammoth,* cave -bear, rhinoceros, Irish elk, etc. It
would seem that about the time of the glacial epoch,
probably just as the great ice-floats began to melt away,
man suddenly appeared among the mighty quadrupeds
which then covered the earth, to contest the supremacy.

The 'Primeval Man. — The life of the pre-historic
man has been classified according to the character of the

* In the valley of the River Somme, near Abbeville, flint implements, associ-
ated with remains of the mammoth, elephant, hippopotamus, rhinoceros, etc.,
were found by M. Boucher de Perthes. Near Amiens, in the same valley, another
deposit of gravel was discovered, containing flint hatchets, poniards, knives,
etc., nearly 400 in number, accompanied also by bones of the above animals.

THE ERA Of1 MIND.

fossil remains in the following manner. (Edouard Lartet,
Vogt, and others.)

1. Epoch of extinct animals, mam-

moth, cave-bear, etc.

2. Epoch of migrated existing ani-

mals, or Reindeer Epoch.

3. Epoch of domesticated animals,

or Polished Stone Epoch.

1. The Bronze Epoch.

2. The Iron Epoch.

I. THE STONE AGE.

II. THE METAL AGE

These terms indicate the successive progress of the
ancient races. Every nation seems to have had some
such stages in its advance. The Indians have hardly
passed out of their stone age. The Sandwich Islanders,
when discovered, were in that age, while the nations of
Asia emerged from it long before the Christian era.
Some of these ages may have been contemporaneous in
different nations.

TONE

GE.

J?poc?i of Uxlinct dmma/s.—ThQ primeval man
during this epoch dwelt in caves, dressed in skins, and
FIG. 113. made weapons chipped

out of the rough flint
(Fig. 113), by means of
which he fought the cave-
bear, hunted the Irish
A Danish Axe-hammer. elk, and speared the mam-

moth. He was rude and barbarous, perhaps a cannibal,

THE STONE AGE.

ana ceremonies/

FIG. 114.

yet he made fire, instruments of offence and defence,
articles of pottery-ware
for domestic use (Fig.
114), sewed skins into
garments, adorned his
person with strings of
rudely - carved shells,
wrought out images
emblematic of his po-
litical or religious views,
and buried his dead in
caves with religious rites

^Reindeer J?poch .

— In this epoch man

advanced in knowledge, learned to work in bone, ivory,

Earthen Vase found in Cave of Furfooz
(Belgium).

* In 1842, on the slope of a hill near Aurignac, an excavator, named Bonne-
maison, discovered a great vertical slab of limestone covering an arched open-
ing. In the cave thus closed up he found the remains of seventeen human
skeletons. These were removed to the village cemetery, and thus lost to science
forever. In 1860, M. Lartet, having heard of the event, visited the spot, which,
during a long course of centuries, had entirely escaped the notice of the inhabit-
ants. The entrance to the cave was concealed by masses of earth, which,
having been brought down from the top of the hill by the action of water,
had accumulated in front, hiding a flat terrace, on which many vestiges of pre-
historic times were found. As no disturbance of the ground had taken place in
this spot subsequent to the date of the burial, this gradual accumulation had
protected the traces of these primeval men. The investigations of M. Lartet
were attended with the following results : —

He found on the floor of the cave a bed of "made ground" two feet thick.
In this were some human remains which had escaped the first investigations ;
also bones of mammals well preserved, and exhibiting no fractures or teeth-
marks, wrought flint- knives, carved reindeer horns, and eighteen small sea-
shells pierced in the center, and doubtless intended to be strung together in a
necklace or bracelet. He found also a quantity of the bones of the cave-bear,
the bison*the reindeer, the horse, etc. The perfect state of preservation of
these bones shows that they were neither broken to furnish food for man nor
torn by carnivorous animals, as is seen in many cases. It must be concluded.

THE ERA OF MIND.

and reindeer-antlers (Fig. 115) ; to catch fish ; to make
saws, knives, and other tools; to form amulets and

charms of bone; to
ornament the in-
struments of the
chase; and in his
leisure to sketch on
ivory the outlines of
the animals he pur-
sued (Fig. 116).

"Polished Stone
JZpoch . — The next

Bone pierced by an Arrow of Reindeer-horn,

epoch witnessed a

still higher condition. Skiffs were made in which the
primitive man ventured out on the sea, and caught the
fish of deeper waters.* He made nets for fishing near the

then, that the stone which closed the entrance to the cavern was moved away for
every interment, and carefully put back immediately afterward. In explaining
the presence of so many foreign objects in the burial-cave, we must admit as
probable that the customs which now exist among savage tribes — such as plac-
ing near to the dead body the weapons, hunting-trophies, and ornaments be-
longing to the deceased — existed among the men of the great bear and mammoth
epoch. In front of the cave was also found the site of an ancient fire-hearth,
where evidently the funeral banquet was held. In this bed of ashes and char-
coal an immense quantity of the most interesting relics were discovered— a
large number of teeth and broken bones of herbivorous animals ; a hundred
flint-knives ; two chipped flints, which are believed to be sling projectiles ;
several implements made of reindeer's horn, etc., etc. Some of the bones were
partly carbonized, others only scorched, but the greater number had been un-
touched by fire. All the marrow bones were broken lengthwise, showing that
they had been used at a feast where the marrow from animal bones furnished a
delicious viand. Traces of the hyena were found at this spot. From all these
signs we infer that after the death of one of these primitive men, his friends
accompanied him to his last resting-place, after which they assembled together
to partake of a feast in front of his tomb ; then every one took his departure,
leaving the scene of the banquet free to the hyenas, which came to devour the
remains of the meal.

* Along the coast of Denmark, in Cornwall and Devonshire, England, in
Scotland, and even in France, have been discovered what have received the

THE METAL AGE.

shore. He domesticated the dog. He attempted agri-

Frc. 116.

Sketch of a Mammoth graven on a Slab of Ivory.

culture ; raised corn, ground it, and thus became less
dependent on the chances of the chase. He interred
his dead in vaults, and erected monuments to mark
their last resting-place. (See Fig. 117).

name of "kitchen-middens." They are immense accumulations of shells from
3 to 10 feet in thickness, and from 100 to 200 feet in width ; their length is some-
times as much as 1,000 feet, with a width of 250 feet. At first seeming, one
would think them banks of fossil shells which had been submerged, and after-
ward volcanically brought to light. But it has been discovered that these shells
belong to four different species which are never found together, and conse-
quently must have been brought there by man. Nearly all the shells are those
of full-grown animals. Also traces of fire— remains of hearths— were found in
these heaps, which, with the other facts, lead to one conclusion. Tribes once
existed there who lived on the products of hunting and fishing, throwing out
round their cabins the remains of their meals, especially the debris of shell-fish.
Hence the name, which signifies " kitchen heaps of refuse." Nearly all these
kitchen-middens are found on the coast, along the fiords, where the action of the
waves is not much felt. Some have been found inland; but this proves that
the sea once occupied those localities from which it has now retired. These
refuse deposits consist mostly of various shells of mollusks — such as the oyster,
the cockle, the mussel, and the periwinkle. Fishes' bones, in great abundance,
are also found. They belong to the cod, herring, dab, and eel. From this we
may infer that the primitive inhabitants ventured far out to sea, as the herring
and cod can be caught only at some distance from shore. The remains also of
the stag, the roe, the boar, and various other mammals are discovered, with
some traces of birds — mostly aquatic species. All the long bones are found split
to extract the marrow.

THE ERA OP MIND.
FIG. 117.

Row of Menhirs or Monuments set up on Tombs at Carnac, Brittany.

ETAL

GE.

This age indicates a great advance in civilization.
Thenard asserted that we may judge of the civilization of
any nation by the degree of perfection it has attained in
working iron. We may safely say that, without a knowl-
edge of the metals, man would have remained a barharian.
Iron ores do not readily attract attention, and their re-
duction is a very difficult process. The method whereby
iron becomes utilized in the arts, generally requires chem-
ical knowledge and high progress in science. Gold, how-

THE METAL AGE.

ever, is found native, and by its glitter attracts the eye
even of the savage. Copper occurs pure, and its ores are
rather widely diffused, as are also those of tin. It is
strange that bronze (brass), which is an alloy of copper
and tin, should have been the first metal used. We can
hardly understand the cause of this, since the metals
must have been known before the alloy could be manu-
factured.

^Bronze JZpoch . — Tools of a better character were
now made, and life wore an improved aspect. Extensive
villages were built on piles* driven deep in the lake-

* The discovery of the remains of lake-dwellings in Switzerland, and their
connection with the bronze epoch —as first asserted by Dr. Keller, of Zurich, and
since agreed to by all archreologists — reveal to us many very interesting facts in
regard to the pre-historic natives of that country. When, in the dry, cold winter
of 1853-1854, the waters of the lakes in Switzerland fell so far below their ordi-
nary level, the inhabitants of Meilen, on the banks of Lake Zurich, thus gaining
from the lake a tract of ground, set to work to raise it and surround it with
banks. In carrying out this work they found in the mud at the bottom of
the lake a number of piles, some thrown down and some still upright, frag-
ments of rough pottery, bone and stone instruments, and various other relics
similar to those found in the Danish peat-bogs. Previous to this, various instru-
ments and strange utensils had been obtained from the mud of some of the
Swiss lakes, and piles had often been noticed standing up in the water, but no
one had thought of attributing any great antiquity to these objects, or, indeed,
made much attempt to explain them. The fishermen had for some time been
acquainted with the sites of some of these lake settlements, in consequence of
having often torn their nets on the piles sticking up in the mud. Thus,
guides were at hand to aid in searching out the mystery of these lake abodes.
More than 200 settlements are already known, and every year fresh ones are
being found. The builders of these lacustrine dwellings seem to have pro-
ceeded on two different systems of construction : either they buried the piles
very deeply in the bed of the lake, and on them placed the platform which was
to support their huts, or they artificially raised the bed of the lake by means of
heaps of stones, fixing in them large stakes to make a firm and compact body.
Sometimes these are so high as to rise above the water, and form artificial
islands ; and some of them are still inhabited.

We may reasonably suppose that need for security prompted the ancient
people thus to construct their dwellings over the water. Encompassed by vast
marshes and impenetrable forests, no means could so effectually secure them
from the attacks of wild beasts as to surround themselves with water. In later

250

THE ERA OF MIND.

FIG. 118.

bottom, looms were erected, cloth was woven and made
into garments (Fig. 118). The horse, ass, ox, sheep and

goat were domestica-
ted in great numbers.
Hatchets, reaping-
hooks, mills, pend-
ants, rings, hair-pins,
barbed fish-hooks,
and numerous arti-
cles of ornament were
manufactured (Fig.
119). The clothing
became more grace-
ful, and the hair was

Woolen Shawl found in a Tomb in Denmark. adorned with the

most elaborate taste.

Wheat, barley and oats were cultivated. The baker's art
was established. Glass was discovered. Mats of bark and
cord were made. Apples, pears, berries, and other fruits
were stored for winter's use.

J?poc?i. — With the discovery of iron, civiliza-
tion rapidly advanced. This metal marked the latest
period of primeval development. The art of metallurgy

times it served to protect them from sudden surprises by their enemies of
other clans. The number of piles used in these constructions is surprising.
They were often sixteen or twenty feet long, and in the stone-heaps were some-
times ten or twelve inches in diameter. The mind is almost confused when it
endeavors to sum up the amount of energy and strong will which, without the
aid of iron implements, must have been bestowed in constructing these settle-
ments. One of the largest, that of Merges, in Lake Geneva, is 71,000 square
yards in area. The huts themselves seem to have been formed of trunks of
trees placed upright side by side, and bound together by interwoven branches.
A coating of earth covered this wattling. Some of these huts having been par-
tially destroyed by fire, arnon^ the charred debris various articles have been
perfectly preserved, such as fishing-nets, basket-work, corn, etc.

THE METAL AGE.

FIG. 119.

had made great progress during the bronze epoch, but
now assumed new importance. Extensive smelting works
were erected.* The potter's
wheel was invented. Better
tools were made (Fig. 120).
Silver and lead were discov-
ered. Coined money was in-
troduced and commerce flour-
ished (Fig. 121), Agriculture
was practiced on a large scale.
Fruit trees were cultivated.
Civilization was fairly

es-

Bronze Vase from the Tomb of Hallstadt.

tablished. At this point the
written records and oral traditions take up the story of
the past, and the naturalist's labors cease as the histo-
rian's begin.

FIG. 1 20.

Knife from the Lacustrine Settlements of Switzerland.

FIG. 121.

The ^Development Theory. — This primeval man
shows no sign of a development from the
higher tribes of animals. No fossil yet
found is a link between him and
the monkey. No ape ever made
any improvement on the condition in
which he was born. Man, on the other
hand, never stays where he starts. He

* Four hundred iron furnaces have been discovered by M. Quiquerez in th«
Bernese Jura.

THE ERA OF MIND.

continually progresses. The very names given to the vari-
ous ages and epochs of his primeval history in Europe in-
dicate this fact. He appears among those huge quadru-
peds whose figures stalk like mighty shadows across the
scenes of the Post-Tertiary Period, and is at once their
lord and master. He uses the bow and spear. He be-
comes a builder and an inventor, makes tools, subdues
the earth, hews down the forest, bridges the river, builds
houses, tames wild animals and converts their strength to
his purposes, while from every element of Nature he
gathers material for use and beauty. Lastly and best of
all, he buries his dead with religious ceremonies, in care-
fully constructed tombs, and deposits in their graves arms
and food for their journey to the spirit-land. "(Togt.)
His thought reaches out into the life beyond, and he be-
trays at once the longings of an immortal soul.

Geology gives us no means of answering that oft-asked
question, whether there was one or were many centers of
man's creation. As far as the facts go, however, the
sameness of the remains, wherever found, evinces a simi-
larity of ideas, and thus tends to prove a common origin
for the race. Those who, disregarding the unity of lan-
guage, of mental constitution, and of the religious senti-
ment of the human race, desire to show that the Mosaic
account is only a partial and blundering one, must look
for arguments elsewhere than in the records of geology.

Geological Theories. — Many of the geological
theories we have discussed may be set aside by future
discoveries, and be proved to have been vain assumptions.
They will yet, however, have served a purpose. The
mind instinctively demands order. Each theory is a cord

THE METAL AGE.

on which to string facts that otherwise might be lost.
Theories are generalizations of truth. They give consist-
ency and interest to a science that otherwise would be
only a mass of discordant and uninviting detail. Our
theories may yet be thrown away, but our facts never,
and we can but be grateful for the former in that they
have helped us to retain the latter.

World Unfinished. — Creation is continually
going on around us. Astronomy teaches that the stars
are changing — new ones flashing out in the sky and
others fading away into darkness. Geology did not cease
when history began. Since the coming of man, vast
physical changes have taken place. The mastodon and
Irish elk vanished with his first appearance. The dodo
of Mauritius is known only by tradition. The animals
of the present — the ostrich, beaver, etc. — are hastening to
extinction. The mud and sands of our sea-shore will be
the rocks of future hills, and the rocks of our hills the
ocean sediment of another age. Rivers have deserted
their old channels; the ocean has encroached on the
land;* lakes and marshes have disappeared; volcanoes

* There is abundant evidence to show a slow subsidence of the whole eastern
coast of the United States, which has been going on for several years past. The
movement is one of alternate elevation and depression within the limits of per-
haps twenty feet. A map of Cape May, dated 1694, shows Egg Island as contain-
ing 200 acres ; it now contains less than an acre at ebb tide, and is entirely
submerged at high tide. The light-house at the Cape has been moved consider-
ably inland on account of the wear. The shore in front of the boarding-houses
at Cape Island must have worn away nearly a mile since the Revolution. Dur-
ing the war of that period, a militia artillery company had its practicing ground
here. Their gun was placed near a house which stood just outside the present
shore-line, and their target was set up at the outer side of a corn-field, three-
quarters of a mile east. Beyond this there were sand-beaches for nearly or quite
a quarter of a mile, and then the sea-shore. The whole of this ground is now
gone, and one of the boarding-houses has been moved back twice. Sandy Hook
has extended out to the northeast a mile since the Revolution. The spot where

THE ERA OF MIND.

have thrown out rivers of lava, and earthquakes have
cracked the earth's crust.

" There rolls the deep where grew the tree ;
O earth, what changes hast thou seen !
There, where the long street roars, hath been
The stillness of the central sea." — Tennyson.

The Origin of Man. — Was man created directly
by God's fiat, or by some intermediate process of second-
ary causes ? "Alas for the impotence of science and the
scope of our finite intelligence!" We bring the subtlest
agencies to the accomplishment of our designs — Heat,
Light, Electricity — but when we seek to develop from
them even the intangible forces which clothe the decay-
ing rock with verdure, or mantle the stagnant pool with
slime, failure inevitably waits upon us. In vain do we
seek to associate vital manifestation with electrical action ;
we may resolve the vital organism into cells and granules
and nuclei, but the life eludes our proudest philosophy.
If, under certain conditions, inorganic matter assumes
organic form, those conditions and the laws which gov-

the first boarding-house was erected at Long Branch, together with the road
behind it, is now all worn away. The loss is sometimes twelve feet in a year.
Where seventy years ago were cultivated fields is now the ship-channel. At
several points in New Jersey an enormous quantity of white cedar is found
buried in the salt marshes. This indicates extensive forests on land now too
low and wet for the growth of trees. Trunks are found sunk at all depths down
to the underlying gravel, and so thick that in many places a number of trials
must be made before a sounding-rod can be thrust down without striking
against them. Tree after tree from one to two thousand years of age lies crossed
above one another in every conceivable direction. These cedar logs are mined
and split into shingles, and thus is carried on a very extensive business. Sub-
marine forests exist on the shore of Martha's Vineyard and also at Rye Beach.
All along the sea-coast, from South Carolina to Florida, similar phenomena are
to be found which seem to indicate a subsidence of the land.— See Cook's Geology
Of New Jersey, pp. 343-373.

CONCLUSION.

ern them are alike unknown to us. And so we pause
on the threshold of created life, and, standing reverently
aside, lay humbly down our little wisdom as we recog-
nize the unfathomable greatness of the ONE ALL-WISE
CREATOR.

" We have but faith : we cannot know ;
For knowledge is of things we see ;
And yet we trust it comes from Thee,
A beam in darkness : let it grow."

CONCLUSION.

We have traced in the dim light of the past the his-
tory of our earth and its inhabitants. Everywhere we
have found a Divine Hand shaping and moulding to
accomplish a Divine ideal. " IN THE BEGINNING GOD."
We can add nothing to the old Hebrew declaration. W<;
have gone back to the origin of man, and there too we
have rested on that sublime truth, " IN THE BEGINNING
GOD." We have winged our imagination backward to the
time when our earth was " without form and void," and
here again we have felt the force of that same statement —
"IN THE BEGINNING GOD." The study of science ought
never to lead one astray from this great fundamental
thought. God has assuredly never written anything in
Nature contradictory of Himself! Science and religion
alike are His offspring. Both will ultimately vindicate
Him and His attributes. During this transitional period
they may oftentimes seem to clash, but they will ulti-
mately come into perfect accord. He who, even now,
from an elevated point surveys the contending hosts on

256

THE ERA OF MIND.

this fiercely-fought field, will see that the scientists and
the religionists are fast setting out, if not even now
moving upon converging lines of thought. By-and-by
they will meet. Forgetting, then, the rancor and bitter-
ness of the past in the joy of newly-found truth, they
will clasp hands, and together cast the crowns of their
triumphs— the triumphs of Science and Christianity— at
the feet of their common Author, and God shall be pro-
claimed LOUD OF ALL!

Disintegration of granite, resulting in the form called tors or cheese rings.

FIRST PART

[ The figures refer to the pages of the book.]

INTRODUCTION. — State the origin of the earth according to the
nebular hypothesis. Why did the earth assume a globular form ?
Describe the appearance of the first crust. The first rain. Why
was the water hot ? What was the effect of the rain ? Describe the
conflict between fire and water.

19. Where do Astronomy and Geology meet? Meaning of the
term "day" in the Scriptures? Give the parallel between the Mo-
saic and the geologic account.

20. Give some idea of the appearance of the earth at that time.
Define Geology.

21. How thick is the earth's crust? How deep has it been ex-
amined? Condition of the interior? Name the six reasons given
to prove that the interior is a melted mass. At what rate does the
temperature increase as we descend ? Illustrate. Name some ar-
tesian wells that furnish warm water.

22. Name some geysers that throw up hot water. Cause of this
difference in temperature? Is the earth's crust steady? What
does this oscillation show? What are volcanoes? How many are
active? Give an illustration of the amount of lava they throw out
at an eruption. Cause of volcanoes?

258 QUESTIONS.

23. How many earthquakes have been recorded in the last half
of a century? Cause of earthquakes?* State in what respects the
earth is a microcosm. In what way is the present to the geologist
the key to the past ?

24-5. By what course of reasoning does thg geologist infer that
certain kinds of rocks were formed by water? Are rocks now being
made in this way? What does the geologist call such rocks?
How does the ocean record the history ofrthe land?

26. Where does the geologist find the history of the past written ?
Has the ocean always been where it is now ? By what course of
reasoning does the geologist conclude that certain rocks have been
thrown up in a melted state from the interior of the earth?

27. What name does he apply to such rocks? Can he be mis-
taken in the principle ? Define fossils. Give some illustrations of
the mistakes the ancients made concerning them. Plater's blunder.
What view was generally held at a later day ?

28. Describe the process of fossilization. Are any fossils now
making? When we find a fossil bone, what conclusion do we draw?
How can a geologist restore the form of an ancient animal, deter-
mine its habits, etc. ? f

* In the text the theory of earthquakes is given as that of " billowy pulsations "
in the crust resting on the waves of a lava-ocean. Dana holds that they are pro-
duced by the folding up of the rocks in the slow process of cooling and conse-
quent contraction. An earthquake wave consists, as in all wave-motion, of a
progressive vibration as well as a vertical oscillation (Phil., p. 128). The upward
vibration seldom exceeds two feet in height. The forward movement has a rate
of twenty to thirty miles per minute, depending on the character of the crust
through which it passes ; in the " undisturbed beds of the Mississippi valley the
rate being greater than among the contorted strata of Europe." Orton says that
no familiarity with earthquakes enables one to laugh during the shock, or even at
the subterranean thunders, which sound like the clanking of chains in the realm
of Pluto. All animated nature is terror-stricken. The horse trembles in his stall.
The cow moans a low, melancholy tune. The dog sends forth an unearthly yell.
Sparrows drop from the trees as if dead. Crocodiles leave the trembling bed of
the river and run with loud cries into the forest. When the earth rocks beneath
our feet, we feel something beside giddiness. " A moment," says Humboldt,
" destroys the illusion of a whole life." We realize an utter insignificance in the
presence of that mysterious Power that guides the forces of Nature.

t " Such is the unity and persistence of plan which runs through the different
classes of the animal kingdom, that a single tooth, whether of a living or extinct
species, will often suffice to enable the expert to disclose all the zoological rela-
tionships of the animal to which it belonged, to delineate its form, and size, and
habits of life ; as the architect from a single capital rescued from a ruined edifice

Q UESTIONS.

29. Illustrate. Why does a geologist think a fossil shell was
once inhabited? What does the shell show? What proof is there
that an Arctic climate once existed in England and France? Is
this good reasoning?

30. What reasons has the geologist for thinking that certain re-
gions were once covered with glaciers or icebergs ?

31. How does he know that a race of cave-dwelling men once
lived in Europe ? That they were contemporaneous with the
hyena? Describe the discoveries that could be made in digging
through an old lake-bottom.

32. Give the history of the lake as deduced from such data. Can
we judge of the antiquity of the lake? State what has been found
in draining old Scottish lake-bottoms. The history indicated by
these remains. Tell about the temple of Serapis.

SECOND PA RT.

LITHOLOGICAL GEOLOGY. — Define. Name the three classes into
which it is divided. Define the term " rock."

40. What common minerals compose the larger part of the
earth's crust? Properties of quartz ? Its tests?

42. Why are quartz pebbles, etc., so abundant ? Size, clearness,
etc., of quartz crystals? What is rock crystal? Why so called?

can declare not only the general style of the entire architecture, but can repro-
duce the size and proportions of the temple whose spirit and method it embodies.
Not less sublime than the work of the astronomer, who sits in his observatory,
and, by the use of a few figures, determines the existence and position in space
of some far-off, unknown orb, is that of the palaeontologist — the astronomer of
time-worlds — who, from the tooth of a reptile, or the bony scale of a fish found
thirty feet deep in the solid rock, declares the existence, ages ago, of an animal
form which human eyes never beheld — a form that passed totally out of being
uncounted centuries before the first intelligent creature was placed upon our
planet — and by laws as unerring and uniform as those of the mathematics, pro-
ceeds to give us the length and breadth of the extinct form ; to tell us whether it
lived upon dry land, in marshes, or in the sea ; whether a breather of air or
water, and whether subsisting upon vegetable or animal food. It is this unity of
the laws of animal life and organization running through the whole chain of ex-
istence, whether past or present, whether extinct or recent, that constitutes the
sublime philosophy of palaeontological studies, and assures us that one enduring
and infinite Intelligence has planned and executed every part of creation."—
Winchelfs Sketches of Creation, p. 175.

UESTIONS.

Its uses ? Illustrate the great variety of forms which quartz as-
sumes. Describe rose quartz.

43. Smoky quartz. Milky quartz. Granular quartz. Its uses.
Amethyst. Why so called? Chalcedony. Carnelian. Sard.
Chrysoprase. Agate. Name the different varieties of agate.*

44. What is a cameo? Describe some celebrated antique
cameos. The process for preparing agates for the market.

45. Describe jasper. Cause of its color? Name and describe
the different varieties of jasper. What is opal? Its appearance?

46. For what is hydrophane noted ? How is this explained ?
What gives the color to quartz pebbles, sand, etc. ? Show that iron
is Nature's universal dye ! Describe flint. Its tests. Hornstone.
Buhrstone.

47. Cause of its cellular structure? Origin of quartz? What
are diatoms? How do they form rocks ?

48. What is tripoli? Fossil farina? Infusorial earth? Noted
localities? Appearance of flint, etc., under the microscope ? What
conclusion is drawn from these facts? Describe alumina. Its
tests.

49. Sapphire. Corundum. Emery. Composition of limestone.
Tests. Lime. Calcite. Iceland spar. Its test. Chalk. Calca-
reous tufa. The Tiber stone.

50. What are stalactites? Stalagmites? Appearance of Oolite?
What is marl? Its uses? Dolomite? Its test ? Marble?

51. Describe the Parian marble. Name some works of art
wrought from this stone. How is the quality of marble often in-
jured? What is verde-antique? Describe the process of sawing
marble. Wherein is this stone especially designed for man's use ?

52. Illustrate the abundance of limestone. What was the origin
of limestone? Of chalk ? What does the abundance of limestone
prove? What is gypsum ? Its tests ? Plaster? Its uses?

53. Forms of crystallized gypsum ? A noted locality? What is
plaster of Paris? WThat are silicates? Name the six prominent
ones. Tests of feldspar. Three varieties of feldspar. Their tests.
What is clinkstone? Common clay?

* The peculiar form assumed by an oxide of iron in the moss-agate is said by
microscopists to be due to the presence of tiny fossil sponges hi the stone.

QUESTIONS. 261

54. Kaolin? Why are bricks red and tobacco-pipes white?
Common name for mica? Its tests? Its uses? In what forms is
it found ? Describe hornblende. Why so called ? Asbestos. Its
uses.

55. Augite. How distinguished from hornblende?* Talc.f
Its tests. What is French chalk ? Soapstone? Uses?

56. What is serpentine ? Its tests ? Why so called ? Its uses ?
What is chlorite? Garnet? Its tests? Ancient name? Tour,
maline?

57. Name the three general classes of rocks. Define sedimen-
tary rocks. Name the four divisions of sedimentary rocks. What
is sandstone ? Conglomerate ? A siliceous sandstone ? An argil-
laceous one ?

58. Name the three kinds of conglomerate. What is a pudding-
stone ? A breccia? A shale ? A sedimentary limestone ? What
are the characteristics of the landscape in a sandy region ?

59. Define igneous rocks. By what other name are they known?
Into what two classes are they divided ? Describe trap-rocks. Why
so called ? Their uses ? Name the four varieties of trap-rocks.
What is basalt ? Chrysolite ? Greenstone ? Common name ?

60. Describe porphyry. Why so called ? What is a porphyritic
rock ? An amygdaloid ?

6r. What form does trap assume in crystallizing? Causes of
this ? Noted trappean scenery ?

* The soft, light-colored pencils in tommon use are made from a soap-stone
rock found at Castleton, Vt. It is a silicate, technically known as argillite. This
is the only deposit fit for pencils as yet discovered in the world. The rock is
blasted, and is worked immediately, as it soon becomes hard and brittle, and
hence useless. The stone is first split into slabs about an inch thick, and then
sawn into blocks about seven inches long and five wide. These are carried to
the " splitting table," where workmen, with a hammer and a bit of steel like the
blade of a knife, split them into little plates about one-third of an inch thick.
The squares are now of a tolerably uniform size, about an inch wide, one-third
of an inch thick, and seven inches long, but are very rough. They are next
passed through a planing-machine, which smooths them, and a rounding-ma-
chine, which cuts off the corners, and then are sawed to the proper length. Each
pencil is afterward sharpened separately on a grindstone. The waste is very
great, as not more than one-hundredth of the original stone appears in the form
of pencils. This refuse is ground three grades finer than superfine flour, and used
to mix with paper pulp to give it body, as it is termed, and a satin finish.

t Talc is found as a compact rock in North Carolina. It is largely used as a
black-board crayon.

Q UE S T I 0 N 8.

62. Characteristic features of the landscape in a trappean region ?
Proof of the igneous origin of basalt ?

64. Curious relation between the civil and geologic history of
trappean countries ? Name the three varieties of volcanic rocks.
Describe trachyte ? Noted peak of trachyte ?* What is lava ?

65. Scoria? Its uses? Pumice? Its uses? What are the char-
acteristic features of the landscape in a volcanic region ? Define
metamorphic rocks.

66. What effect would melted lava have on sedimentary rocks ?
Illustrate. Cause of fossils in certain kinds of marble ? Imperfec-
tions in marble ? Composition of granite? How may its constitu-
ents be distinguished ?

67. What is graphic granite ? Is the structure of granite uni-
form ? Its value for various uses ? Its location in the earth's
crust ? Process of quarrying granite ?

68-9. Estimate of granite by the ancients ? Is granite a primi-
tive rock ? Has the original crust of the earth been preserved un-
changed ? State what changes it has probably undergone. Could
granite crystallize directly out from lava ? State the theory of the
formation of granite. If granite be not an igneous rock, how do
you explain the fact that it has been thrown up in a melted state ?
What are the various aspects which granite assumes in a land-
scape ?

71. What is the general appearance of a granitic region ? What
effect has the pnrity and sublimity of nature upon the inhabitants ?
Difference between granite and gneiss ?

72. Origin of gneiss ? Its use ? Appearance of gneiss hills ?

73. What is mica schist? Character of a mica schist landscape?
What noted scenery is of this description ? What is syenite ? Why
so called ? Was this name correctly applied ? Is " Quincy granite "
a true granite ?

* Chimborazo is a trachytic dome, which is a characteristic feature of the moun-
tain scenery among the Andes, as sharp granitic pinnacles are of the Alps. (See
page 69.) It is a majestic pile of snow, white as if cut out of spotless marble.
Yet it once gleamed with volcanic fires. Its ancient name, Chimpurazu, meant
mountain of snow. It is a little singular to notice how many lofty peaks in the
world are thus named— Himalaya, Mont Blanc, Hoemus, Sierra Nevada, Ben
Nevis, Snowdon, Lebanon, White Mountains, Chimborazo, and Illimani.— Or-
ion's "A ndts and the A mazon."

Q UE S TI 0 NS.

74. What is quartzite ? Repeat the effects of metamorphic action
on limestone. Cause of colored veins in marble ? How are rocks
classified according to their structure ?

75. Which class is the more abundant on the exterior of the
earth's crust ? On the interior ? Which is of the greater value in
geologic study ? Does the crust remain of the same thickness ?
How are igneous rocks worked over into stratified rocks ? How
are stratified rocks generally deposited ?

76. Show how igneous action has disturbed this uniform arrange-
ment. Value of this disturbance in geologic study ? Define out-
cropping.

77. Define stratum, formation, group, and lamina. Name and
define the various terms used to indicate the position of strata.

78. When are strata conformable? What is diverse stratifica-
tion ? Distinguish between lamination and stratification. State
the circumstances under which different kinds of lamination are
produced.

79. Define a fault. A jointed structure. Illustrate.

80. Value to the quarrymen ? Cause of these seams ? What are
folds? How produced ?

81. What is a decapitated fold ? Effect in apparently displacing
strata ? Illustrate.

82. What is a concretion ? The nucleus ? A septarium ?

83. A claystone ? A geode ? A beetle-stone ?

84. A slate structure ? How produced ? How do the unstrati-
fied rocks occur?

85. What is a vein ? A dike ? Meaning of the term ?

86. State Hugh Miller's beautiful comparison.

87. How can the relative age of veins or dikes be estimated?
What proof is there that some veins have been filled from below
with melted matter ?

88. Describe the various ways in which Nature mends her rock-
rents.

go. How have metallic veins been formed ? What is a lode?

Q UE S TI 0 N S.

THIRD PART.

HISTORICAL GEOLOGY. — Define historical geology. Name some
of the difficulties the geologist finds in reading this history. Value
of fossils? Why does the identification of a fossil identify a forma-
tion ? Are the geologic ages clearly separated ? What terms are
used to designate the lesser divisions ?

96-98. Name and define the five different Times of geologic his-
tory. On what are these divisions based ? Length of geologic
history ?

THE Eozoic TIME. — Name the Eozoic periods. Location of the
Eozoic rocks. Where is the oldest land in America?* Was there
ever a true Azoic time? Is it definitely fixed?

101. Name the kinds of rocks. How formed? What ores do
they contain ? What is the Eozoon Canadense. What are rhizo-
pods?

102. Is the Eozoon universally accepted as a fossil ? What effect
would its admission have?- State the probability that life existed
at that early day, and that vegetable life had the precedence. How
is bog-iron ore formed ?

103. How are the relative ages of mountains indicated ? What
are the oldest mountains in America? Describe the effect of the
metamorphic action on the Eozoic rocks. Cause and effect of the
upheavals.

104-5. Show how the frame-work of the continent was developed
in the Eozoic Time. The parallel which exists between the Mosaic
and geologic accounts.

THE PALEOZOIC TIME. — Name the ages of the Paleozoic Time.
The periods. What is the Cambrian system ?

* The oldest land in South America is in Guiana. Its granite peak rose above
the ocean an island where now expands a continent. Its Eozoic rocks, togethei
with those of Brazil, which afterward appeared as a cluster of islands, were for
ages the only dry land south of the Canada Hills While the Creator was build-
ing up a continent at the north, the south seems to have been left for a later age
to develop. Carboniferous vegetation mantled the coal regions with a gorgeous
flora, monstrous saurians paddled the waters of the upper Atlantic coast, and
huge dinotheria wallowed in the mire where now stand the palaces of Paris,
London, and Vienna, but as yet only the broad table-land of Guiana and Brazil
appeared above the waste of the Paleozoic Sea.— See Ortvrfs " Andes and the
A mazon"

QUESTIONS.

THE SILURIAN AGE. — Why is the age so called? Name the
periods of the Silurian Age. Why is the New York survey taken
as the basis of the Silurian and Devonian Ages.

108. State the method by which the continent grew. The general
characteristics of the Silurian Age.

109. Location of the Potsdam rocks? Kinds of rocks? What
are mollusks ? What is the Acadian Epoch ?

no-iii. What does the calciferous sandstone of New York be-
come at the west ? What is it there called ? What is the Canadian
Epoch? Describe the lingula. The trilobite. Peculiarity of its
eyes. Name the parts of the trilobite.

112-114. Describe the atmosphere of the Potsdam Period.* The
early Silurian beach. What subkingdoms of animals were repre-
sented ? Was there any vegetation? Any distinction of zones ?
Reasons for this uniformity ? Show how changes in the sea pro-
duced corresponding changes in the life and the rock. What
geologic events occurred in the Lake Superior region ? What are
the Sculptured and Pillared Rocks of Lake Superior? What val-
uable ores are found near Lake Superior ?

115. Draw the parallel between the Mosaic and geologic ac-

* Nature does nothing by halves. She does not stop at fractions of enterprises.
She never forsakes a part until it becomes a whole. Her works are often a pro-
cess ; often is the process long, but provision is always made for finishing up in
a congruous manner whatever she has undertaken. Many human works are
finally forsaken at various stages of incompleteness — machines, edifices, books.
Nature is no Michael Angelo, leaving piles of unfinished productions. All her
parts bid us look for wholes. Did you ever find a fraction whose integer is not
come or coming ? When you see the crescent moon, be sure that the rest of the
sphere is by its side, though for the present unillumined. Look more closely ;
perhaps you may discern the old moon in the new moon's arms. Look more
closely ; perhaps you may discover over against yonder organic need in Nature
a full supply for that need which Nature has provided. But whether you dis-
cover it or not, make sure that the supply exists. Nature does not waste herself.
She has no fondness for throwing herself away either wholly or in parts. If you
find one of her reservoirs, make sure that there is something to put in it, and as
much as it will hold. If you find one of her tools, be certain that it has some-
thing to do, and as much as it can do well. A good and careful provider is she,
and never to be reckoned as an infidel who does not care for his own ! Cuvier
finds a bone, and he at once reconstructs the whole animal to which it belongs.
How? On the observed fact that whatever is needed to complement a full
mechanism in Nature exists or has existed— that wherever shines a Castor of a
demand, over against it shines also the twin Pollux of a supply.—
pp. 233-5.

Q UE STI 0 NS.

counts. Location of Trenton rocks? Principal kinds of rocks?
Name the epochs in New York. What is St. Peter's sandstone?

116. The Galena limestone? Peculiarity of its scenery?

117. Characteristic fossils of the Chazy, Bird's Eye and Black
River limestones. What are Gasteropods ?

118-120. Describe the orthoceratite. What is the siphuncle ?
What are Brachiopods? Cephalopods ?

120-121. Location of Hudson rocks ? Name the epochs in New
York. By what name is the formation known at the west ? Kinds
of rock ? Does it contain any coal ? Describe the graptolite.

122. Were species constant? Did animals die as now? What
subkingdoms of animals existed? Any terrestrial plants ? What
mountains were elevated at the close of the period ? How is this
known ?

123. What was the Geography of Hudson Period ? Location of
Niagara rocks ? Why so called ? Name the epochs in New
York.

124. What is Niagara limestone called in Chicago? Minerals at
Lockport ? Appearance at the west ? What abundant and inter-
esting fossils ? Describe the fucoids.

125. The crinoids. What common name has the crinoid ?
What is crinoidal (encrinital) limestone ? Appearance when pol-
ished ?

127. Location of Salina rocks? Kinds of rocks?

128. Why is it so destitute of fossils ? Explain the Salt Springs.
Location of the Lower Helderberg rocks ? Kind of rock ? Name
of the lower beds ? What is said of the abundance of fossils ?

129. Describe the eurypterus. The tentaculites. What brach-
iopod is common ? Geography of this period.

130. Location of the Oriskany rocks. What is the character of
these rocks ? What fossil is common ?

131-2. What is said of this old Appalachian sea-beach? Of the
climate ? What animals took the lead ? What classes were yet
wanting to complete the scheme of life ? Illustrate the uniformity
of Nature in all ages. The changes which took place in the life at
various times.

THE DEVONIAN AGE. — Why so called ? What name has it in
England? Is it a red sandstone in America? Name its periods.
Describe the general characteristics of the age. What is the promi-
nent feature ?

QUESTIONS. 267

136. What is a ganoid ? Name and describe the five principal
kinds of fish — the coccosteus, the pterichthys, the cephalaspis, the
holoptychius, and the osteolepis.

137. Illustrate their singular union of reptilian and fishy traits.
What is a comprehensive type? A prophetic and a retrospective
one?

138-9. Location of the Upper Helderberg rocks? What other
name is applied to them? Why? Name the epochs. Which stone
is most valuable for building purposes? What is "chert"?
Characteristic fossils? Location of the Hamilton rocks?

140. Name the epochs and describe the different rocks. Physi-
cal features of districts underlaid by Hamilton rocks. What is the
Cliff limestone ? The Tully limestone ?

141. By what name is the Genesee slate known at the west?
Describe the goniatite. The cup coral. Conchifers. Difference
between them and Brachiopods.

143. For what is the phacops bufo distinguished ? When did
terrestrial plants first appear? Location of Chemung rocks?
Name the epochs in New York. Under what circumstances were
the Chemung rocks deposited?

144. What are its prominent fossils? Origin of the name?
Locate the Catskill rocks. What are their characteristics? The
fossils ? Name a common one ?

THE CARBONIFEROUS AGE. — Why so called ? Name the periods.
Describe the general characteristics of the age. Its geography.
The conditions favorable to the growth of vegetation. The forma-
tion of coal. The frequent oscillations of the land.

152. Location of the Subcarboniferous rocks? Kinds of rock?
Curious appearance which they sometimes present? Prominent
fossils? Describe the "sink holes" found in this formation. The
caves. Name the subdivisions of the Subcarboniferous Period in
Illinois. What group furnishes beautiful geodes? What are the
so-called "Rock Cities? " Where are they found ? How are they
formed ?

154. Peculiarity of the fish found in the Mammoth Cave ? What
animals appeared, as it were, before their time? Location of Car-
boniferous rocks? Name the six great coal-fields of the United
States. What are the False Coal Measures?

155. Kinds of rock? State some facts with regard to coal

Q UE S TIO X S.

seams. The effect of pyrites. What are the characteristic fos-
sils ?

156. Describe the Carboniferous vegetation. The ferns. The
calamites.

157. The sigillarise. The lepidodendra. The stigmariae. The
conifers. Reptilian remains. Insects. Fishes.

162. Location of Permian Period. Why so called ? Kinds of
rock ? Curious kind of limestone found near Manhattan, Kansas ?

163. Describe the character of the Permian fossils. The Appa-
lachian revolution.

164-5. Illustration of the subsequent denudation seen at Cham-
bersburg, Penn. The metamorphic action. Beneficent effects of
this upheaval and metamorphism. The progress of life.

THE MESOZOIC TIME. — Name the periods of the Mesozoic Time.
The general characteristics of the Age of Reptiles.

167. Grand characteristic ? The geography ? Origin of the
terms Triassic and Jurassic ?

168. What name is sometimes given to the Triassic rocks in
Europe? What are the European divisions of the Jurassic rocks?

169. Location of the Triassic and Jurassic rocks in the United
States ? Describe the formation of the rocks. Kinds of rock. Is
coal found ?

170.- What change took place in the character of the vegetation ?
Describe the cycad. Show that it is a comprehensive type. What
classes now made their appearance? Had birds or mammals been
known before? Describe the various kinds of fossils — insects,
fishes, oysters, crinoids, etc.

171. In what families did the class of cephalopods culminate?
Describe the ammonite.

•172. How did the ammonite sink ? Describe the belemnite.

173. Common names? What is said of the cuttle-fish? The
ichthyosaur ?

174. Coprolites? Beetle-stones?

177. Tell the story of Mary Anning.

178. Describe the plesiosaur. The pterodactyle. How were the
fins of the Devonian fishes a prophecy of man?

Q UE ST 1 0 NS.

1 8 1. Describe the dinosaurs. What are the names of the princi-
pal of these land reptiles?

182. Describe the megalosaur. The iguanodon. The restora-
tion of the latter animal. What striking illustration of the mutual
adaptation of the various parts of the animal occurred in the restora-
tion of the megalosaur?* What naturalist discovered this principle
in comparative anatomy (p. 203) ?

183. Describe the labyrinthodon. The ramphorhyncus.

184-5. The "bird-tracks" of the Connecticut valley. What is
said of the animal by which they were made ? What was the cli-
mate at that time ?

1 86. Describe the Triassic salt-beds of Europe. The Triassic
gold-bearing rocks of California. What was the origin of the gold
placers?

* The following is an extract from a letter on this subject received from Dr.
Hawkins too late for insertion in its proper place, but which is too valuable to be
omitted :

" In the first instance, I was much affected toward it by reading that admirable
work, The Bridgewater Treatise on Geology, written by the Rev. Dr. Buckland,
in which he describes the teeth of that gigantic saurian, and so graphically com-
pares them to the combination of knife, saw and scimeter, which, with the fossil
fragment of the jaw in my hand, could not fail to impress me with a precise idea
of the manner in which this creature devoured its prey. He did not snap and
swallow like an alligator, but did, with tooth and claw, cut off and tear the flesh
of his victim, like the lion or tiger. The fragment of the jaw also gave a definite
conception of the dimensions of the head, and explained the necessity for the
animal to have an active power over the formidable weapons with which he con-
quered and devoured his prey. To do this successfully, it was necessary for the
strong tendon attached to the back of the head to be also firmly anchored at its
other extremity to the long spines of the nerve-arches at the junction of the neck
and back, as in the horse, stag, elephant, tiger, and all animals having an active
use for a large and heavy head. This theoretical reasoning and conviction 1 em-
bodied in a preliminary sketch with the elevated ridge on the fore part -of the
back, to submit to the learned savans whorr* I had the privilege of consulting at
that time, and by whom it was condemned as exceptional in the case of reptiles,
My convictions, however, were too strong to allow me to yield to their decision,
I therefore commenced this gigantic model in the spring of the year 1854, and
completed it the ioth June of the same year.

The supposititious hump-like ridge continued to excite various criticisms as to
its probability. At the end of the same year I had the pleasure of receiving a
visit from Prof. Richard Owen to congratulate me on the discovery in the
Wealden sandstone, Sussex, of the bones which justified the exceptional fqrtn^
which I had predicated."

Q UESTIONS.

187. Describe the disturbances that marked the close of the
Jurassic Period. What noted scenery is of this era? Location ot
the cretaceous rocks ? Kinds of rock ?

188-9. Describe the " green-sand " of New Jersey. What is said
of the cretaceous coal-beds? Appearance of chalk under the mi-
croscope? What is said of rhizopods? Curious story told of
Ehrenberg ?

190. What is said of the deep-sea dredgings ? Are we not now
living, in a certain sense, in the Cretaceous Period ? Are the
American fossils of this period different from the English? Why?

191-4. Describe the cimoliasaur. The mosasaur. The snapping-
turtles. The crocodiles. The dinosaurs. The hadrosaur. The
Iselaps.

Describe the great disturbances which took place at the close of
ihe Mesozoic Age. Cause.

CENOZOIC TIME. — Name its periods. Its general characteristics.

196. Its geography. The epochs of the Tertiary Period. Origin
of the term " Tertiary." Geological condition of Europe. Euro-
pean divisions of the Tertiary.

197. Location of the Tertiary rocks. How do we determine the
way in which its deposits were formed ? Describe the " pine bar'
rens." Extent of Tertiary rocks on the Pacific coast.

198. Kinds of rock. What is nummulitic limestone ? Where
found ? The Tertiary coal-beds? Is coal found below the Carbon-
iferous rocks? Above? What is said of the abundant vegetation?

199-202. What peculiar kinds of plants, not belonging to those
regions at present, are found fossil ? What do they teach ? How
many species of Tertiary shells? Their appearance? Name the
various kinds of animal remains. What is said of the insects
found ? * Describe the zeuglodon.

* The story that these beds tell seems to be this : A large fresh-water or brack-
ish lake existed, covering a considerable portion of western Colorado and eastern
Utah. Streams carried down fine sediment and free petroleum, from numerous
springs in the surrounding country, for ages ; the petroleum increased in flow
until the sediment of the lake became thoroughly charged with it, and the can-
nelite was the result. A change in the level of the country and the course of the
streams is indicated by the overlying sandstones and conglomerates, nearly desti-
tute of petroleum, and at least one thousand feet in thickness. During the time
that this immense amount of sediment was being deposited, willows, maples,

QUESTIONS.

203. Give an account of the discoveries made by Cuvier in the
Paris basin.

204. What was probably the character of this region at that time ?
Describe the paleotherium. How do we know that flowers existed
in the Tertiary Period ?

205. What is said of the Bad Lands? Where are they? What
fossils do they contain ? What animals, since domesticated by
man, inhabited the shores of that Tertiary sea ? * Describe the
titanotherium.

206. What was the probable origin of this region ? Were there
probably more than one of those great fresh-water lakes in the
Tertiary Period?

207. Name the epochs of the Post-Tertiary. Condition of the
continent at this time. What change ensues ?

208. What is the Drift ? Its extent? What is said of bowlders —
their size and appearance ?

209. From what direction did they come ? Illustrate.

210. What are lost rocks ? Why are bowlders more abundant at
the east than at the west ? What are glacial striae ? Describe their
appearance. What is their general direction? On which side of
mountains are they found ?

212. How high do they extend ? Describe the formation of
glaciers in Alpine valleys.

215. Define the different kinds of moraines. Tell how blocks
are conveyed to a distance. How striae are cut.

oaks, and many strange trees grew on the land, palaeotheres and turtles swam in
the waters, and clouds of insects sported over its surface. The bitumen seems to
have flowed from the shales as petroleum after their upheaval, and to have hard-
ened in time into its present form. The character of the ancient vegetation is
shown by the fossil wood found in great abundance. — Proc. Boston Soc. of Nat.
History, 1866.

* " Tt is a marvelous fact in the history of mammalia that in South America a
native horse should have lived and disappeared, to be succeeded in after years by
countless herds descended from the few introduced by the Spanish colonists."
(Darwin.) These domestic animals, which were then native in America, were
not of exactly the same species as those now used by man. The fossil remains of
a horse have been found at the west, which, when alive, could not have been
three feet high. Horses had entirely disappeared from the continent when the
Spaniards landed , and the Indians supposed man and beast to be one animal

QUESTIONS .

216. Name the evidences of former glaciers. Describe the great
glacier on the coast of Greenland.

217-18. How are icebergs formed? What effect do they have in
the transportation of rock and formation of striae ? Describe the
origin of the glaciers of the Drift epoch. Cause of the cold.*
The effects.

219. What change occurred in the Champlain Epoch? Its effect?
What proof have we that river-channels were filled by these
glaciers ?

220-21. Effect of the glacier-streams ? How does the coarseness
of the Drift vary? Effects of this change? Describe the continen-
tal elevation which took place at the beginning of the Terrace
Epoch. Its effect ? Was the elevation uniform and steady ?

222. What are the proofs of these oscillations ?

223-4. How were terraces formed ? Which were made in the
Champlain Epoch? The Terrace? What are ancient sea-beaches?
How are they known ? How high are they found ?

225-6. Localities of Post-Tertiary fossils? Do they resemble
modern species ? What animals led the life of the period ? Name
the principal quadrupeds Describe the mammoth.

* There is a growing conviction that the cause of this glacial cold must be
sought among astronomical phenomena. It has been suggested, i. That we are
now moving through a comparatively starless, and hence cheerless, region ot
space ; and that as the earth passes from densely to thinly-clustered portions, and
vice versa, the heat received and consequent temperature must vary ; 2. That
the axis of the earth may not have always pointed in the same direction or at the
same angle as now, and that any variation would have produced a change of cli-
mate ; 3. That during the Great Year of the astronomers, about 21,000 common
years, each hemisphere has two seasons (see Astronomy, page 121, et seg.}. Dur-
ing half of this time the northern hemisphere has its summer in aphelion, and
winter in perihelion ; while in the other half this is reversed. When the Great
Winter prevails at the north pole, there is an accumulation of ice and snow.
This changes the center of gravity of the earth. The water will flow thither to
adjust the equilibrium, and thus overflow a part of the northern hemisphere.
These Great Summers and Winters, with their accumulations of snow and ice,
and consequent submergence of the land, have occurred, it is thought, alternately
at either pole at intervals of about 10,500 years through all the past. In the year
1250 (see Astronomy, p. 129) the Great Winter terminated at toe soutn poie,
where foi 1-2,500 years these accumulations had been gathering. In the same
vear the Great Northerr: Sum.ner culminated. The hemisphere which has its
winter ;n anbeuoa is not onlv further from tn % sun. tout has a winter of eicht davs

QUESTIONS. 273

227. The locality of fossil ivory in Siberia ? What curious legend
have the Tartars ? Describe the discovery of a mammoth preserved
in ice.

228. The mastodon. How can mastodon remains be distin-
guished from those of the elephant?

229. What was the mastodon's food? How is this known? De-
scribe the megatherium. What was its food ? Uses of its tail '
Was its structure adapted to its life ?

230-4, Describe the glyptodon. The Irish elk. The cave-beai,
Why so named ? The hyena. Discovery of the Kirkdale cave.

236. What is said by Whitney of the Glacial Epoch in California ?
Is any Drift found in Oregon ?

237. Origin of canons. What is the Loess of the Nile? The
Rhine? The Mississippi valley?

238. Its location and appearance? Its fossils? What are sand-
dunes ? Where found ? How formed ?

THE ERA OF MIND. — Does Geology tell when man appeared?
Where are his remains found ?

244-7. Name the classifications of these primeval remains
What do these terms indicate? Were these ages coeval? De-
scribe the man of the Stone Age in the first epoch. The second
epoch. The third epoch.

248-9. Influence of the metals in advancing civilization ? What
metals were first used ?

250. Describe man's progress in the Bronze epoch. The Iron
epoch.

longer duration (Astronomy, p. 118). M. Adhemar has worked out this theory
very fully. He claims, however, that owing to the movement in the Earth's
orbit (Astronomy, p. 128), the Great Year is only 21,000 years long ; each hemi-
sphere having a summer of 10,500 years and a winter of equal length. The Great
Summer of the northern hemisphere culminated, according to his calculations, 1248
B.C. Since that date our Great Winter has been in progress. Our pole, in its
turn, goes on getting cooler continually ; ice is being heaped upon snow, and
snow upon ice, and in seven thousand three hundred and eighty-eight years the
center of gravity of the earth will return to its normal position, which is the
geometrical center of the spheroid. Following the immutable laws of central
attraction, the southern waters accruing from the melted ice and snow of the
south pole will return to invade and overwhelm once more the continents of the
northern hemisphere, giving rise to new continents, in all probability, in the
southern hemisphere.

A TRIASSIC FISH.

Eurinotus ceratocephalus.

ACALEPH, Ak'-a-lef.
AGATE, Ag'-ate.
ALBITE, Al'-ffite.
ALUMINA, A-lu'-me-na,.
ALUMINIUM, Al-U-min'-e-um.
AMETHYST, Am'-e-thyst.
AMYGDALOID, A-mlg'-da-loid.
ANOPLOTHEBIUM, An-o-plo-the'-re-um.
ARGILLACEOUS, Ar-fil-a'-shus.
ASBESTOS, As-bes'-tus.
ASTEROPHYLLITE, As-Ur-off'-e-lite.
AUGITE, Aw'-jlte.

BASALT, Ba-sawlV.
BELEMNITE, Be-lem'-rilte.
BRACHIOPOD, Brack'-e-o-pod.
BRYOZOAN, Bri-o-zo'-an.

CALAMITE, Kal'-a-mite.
CEPHALASPIS, Sef-a-las'-pis.
CEPHALOPOD, Sef'-ctt-o-pod.
CHALCEDONY, Kal-s$d'-o-ny.
CHRYSOPRASE, Krys'-o-prase.
COCCOSTEUS, Koc-cos'-te-us.
CONCHOIDAL, Kon-koi'-dal.
CONGLOMERATE, Kon-glom'-e-rate.
CONIFER, Ko'-ni-fer.
CORAL, Kor'-al.
CRETACEOUS, Kre-ta'-shus,
CRINOID, Krl-noid.
CRUSTACEAN, Krus-ta'-sfie-an.
CYCAD, Sy'-kad.

DEVONIAN, De-v5'-ne-an,
DINOSAUR, Di'-no-sawr.
DINOTHERIUM, Di'-no-the'-re-um.
DODECAHEDRON, Do-dec-d-he'-dron.

DOLOMITE, Dol'-o^nite ; (Dolomien. a

French geologist.)
DOLERITE, Dol'-e-rite.

ECHINODERM, E-kin'-o-derm.
ECHINOIDS, Ek-i-noids.
ENCRINITE, En'-kre-nite.
ENDOGEN, En'-do-jen.
EURYPTERUS, Eu-ryp'-te-rus.
EOCENE, E'-o-seen,
EQUISETACE^:, E-que-se-ta'-she-e.
EQUISETUM, Eq-ue-se'-tum.
EXOGEN, Ex'-o-jen.
EozoQN, E-o-zo'-an.

FAUNA, Fawn' -a.
FELDSPAR, Feld'-spar.
FORAMINIFERA, Fo-ram-m-if-er-a.

GANOID, Ga'-noid.
GASTEROPOD, Gas'-ter-o-pod.
GEODE, Je'-5de.
GLACIER, Ola-seer.
GNEISS, Nice.
GONIATITE, Go'-ni-a-tite.
.GRANITE, Gran'-it.
GRAPTOLITE, Grap'-to-lite.
GYPSUM, Jip'-sum.

HADROSAUR, Ha'-dro-sawr.
HIPPOPOTAMUS, Hip-po-p8t'-a-mu8.
HOLOPTYCHIUS, Hol-op-tik'-e-us.
HORNBLENDE, Horn-blende.
HYL.EOSAUR, Hy'-k-o-sawr.

ICHTHYOSAUR, Ich'-the-o-sawr.
IGNEOUS, Ig'-ne-us.

GLOSSARY.

IGUANODON, Ig-wdn'-o-don.
INFUSORIA, In-fu-zo'-re-a.

LAMELLIBRANCHIATE, Ld-mel-e-brank'-

e-ate.

LEPIDODENDBON, Lep-e-do-den'-dron.
LIAS, Li'-as.
LIGNITE, Lig-mte.

MASTODON, Mas'-to-dm.
MEGALOSAUB, Meg'-a-lo-sawr.
MEGATHERIUM, Meg-a-the'-re-um.
METAMOBPHIC, Met-a-mor'-phic.
MIOCENE, Mi'-o-seen.
MOLLUSCA, Mol-lm'-ca.
MORAINE, Mo-rain'.
MOSASAUR, Mo'-sa-sawr.

NODULE, Nod'-ule.
NUMMULITE, Num'-mu-ftte.

ONTX, O'-nix.
OOLITE, O'-o-tite.
ORTHOCERATITE, Or-tho-cer-a-ttte.

PALEONTOLOGY, Pal-e-on-tol'-o-gy.
PALEOTHERIUM, Pal-e-o-the'-re-wn.
PALEOZOIC, Pal'-e-o-zo4c.
PLESIOSAUR, PU'-sl-o-sawr.
PLIOCENE, Pli'-o-seen.
PORPHYRY, Por'-fe-ry.
PROTOZOAN, Pro-tozo'-an.
PTERICHTHYS, Ter-ik'-thys.
PTKBODACTYLE, Ter-ro-dacf-tyl.

PTEROPOD, Ter'-ro-pod.
PYRITES, Py-ri'-teez.
PYROXENE, Plr-ox'-een.

QUARTZ, Kworts.

RHIZOPOD, ttz'-o-pod.
RAMPHORHYNCUS, Bam-forWin'-kut.

SAURIAN, Sdw'-ri-an.
SELENITE, SZl'-en-ite.
SERPENTINE, Ser'-pen-fine
SIGILLARIA, Sig'-il-la'-re-a.
SILURIAN, Si-lu'-re-an.
SIPHUNCLE, SR-fvnk-kl.
STALACTITE, Std-lac'-ttte.
STALAGMITE, Std-ldg'-mite.
STEATITE, Ste'-a-tite.
STIGMARIA, Stig-md'-re-a.
STRIA, Strl-a.
SYENITE, Si'-en-ite.

TALC, Talc.

TENTACULITES, Ten'-tac-u-litf.
TOURMALINE, Toor'-ma-Vin.
TRACHYTE, Trd'-kite.
TRILOBITE, Tn'-lo-ffite.
TUFA, Tu'-fa.

VERD-ANTIQUE, Verd-an-teek'.
VERTEBRA, Ver'-te-bre.

WEALDEN, Weeld'-n.
ZOOPHYTE, Zt/-o-flt*.

Boulders.

Acadian Epoch, 109.

Acalephs (Sea Nettles) 107.

Agate, 43.

Alabaster, 53.

Alhite, 53.

Alluvial Deposits, 237.

Alumina, 48.

Amethyst, 43.

Ammonite, 171

Amygdaloid, 60.

Anoplotherium, 203.

Appalachian Beach, 131.

Appalachian Metamorphism, 164.

Appalachian Mountains, 110, 164.

Appalachian Kevolution, 163.

Archaean, 99.

Artesian Wells, 21.

Articulates, 132.

Asbestos, 54.

Athens Marble, 124.

Atmosphere, 112.

Augite, 55.

Azoic Time, 98.

Bad Lands, 204.

Basalt, 59.

Basaltic Pillars, 63.

Beetle Stones, 84.

Belemnite, 172.

Bird's Eye Limestone, 115.

Bird Tracks, 184.

Black River Limestone, 115.

Black Slate, 141.

Bloodstone, 45.

Blue Limestone (Trenton Epoch).

Bog-iron Ore, 102.

Bowlders, 208.

Brachiopods, 118.

Breccia, 58.
Bronze Epoch, 249.
Bryozoans (Moss-animal).
Buhrstone, 46.

Calamites, 156.
Calc Spar, 49.
Calcite, 49.
Cameo, 44.
Camel, 240.

Canadian Divisions, 99.
Calciferous Epoch, 110.
Cambrian Period, 107.
Canadian Epoch, 110.
Cafion, 236.
Carbuncle, 56.
Carboniferous Age, 149.
Carboniferous Period, 154.
Carnelian, 43.
Catskill Period, 144.
Cauda-Galli Grit, 138.
Cave Bear, 230.
Cenozoic Time, 194.
Cephalaspis, 137.
Cephalopods, 118.
Chalcedony, 43.
Chalk, 49, 189.
Chazy Group, 115.
Champlain Epoch, 219.
Chemung Period, 143.
Chert, 124, 139.
Chlorite, 56, 75.
Chronology, 30.
Chrysoprase, 43.
Chrysolite, 59.
Cimoliasaur, 190.
Cincinnati Limestone, 121,
Clay, 53.

INDEX.

Clay Stones, 83.

Cleavage, 41.

Cliff Limestone, 140.

Clinton Group, 124.

Clinkstone, 53.

Coal, 155.

Coccosteus, 136.

Comprehensive Type, 137.

Conchifers, 141.

Concretions, 83.

Conglomerate, 57.

Conifers, 157.

Continent, Outlines of, 104, 108.

Coprolites, 174.

Coral, 113.

Corniferous Period, 138.

Corundum, 49.

Cretaceous Period, 187.

Crinoids, 125.

Crocodiles, 191.

Crust of Earth, 21.

Crustaceans, 109.

Cycad, 170.

Denudation, 82.

Deep-Sea Dredgings, 190.

Development Hypothesis, 251-

Devonian Age, 134

Diatoms, 47.

Dikes, 86.

Dinoceras, 205.

Dinosaur, 181, 191.

Diorite, 60.

Dip, 78.

Diverse Stratification, 79.

Dislocations of Strata, 76.

Dolomite, 51.

Dolerite, 59.

Drift Epoch, 207.

Dye Stone, 124.

Earthquakes, 23.
Elasmosaur, 190.
Elephant, 227.
Emery, 49.
Eocene, 196.
Eozoic Time, 98. *
Escarpment, 78.
Eurypterus, 129.
EozoOn Canadense, 102.

Faults, 80.
Feldspar, 53.
Fingal's Cave. 61.

Flint, 46.
Folds, 81.
Fossil, 27.
Fossil Farina, 48.
Fucoids, 117.

Galena Limestone, 116.
Ganoids, 135-6.
Garnet, 56.
Gasteropoda, 117.
Genesee Slate, 141.
Geodes, 84.

Geology, Definition of, 20.
Geysers, 22.
Glacial Epoch, 207.
Glacial Striae, 210.
Glaciers, 29, 212.
Glyptodon, 230.
Gneiss, 72.
Gold Rocks, 186.
Goniatite, 141.
Granite, 67.
Graptolite, 121.
Green Mountains, 122, 131.
Greenstone, 59.
Gypsum, 52, 128.

Hadrosaur, 191.
Hall, James, 107.
Hamilton Period, 139.
Helderberg Period, 138.
Helderberg, Lower, 128.
Herkimer Shales, 120.
Holoptychius, 137.
Hornstone, 46.
Hornblende, 54.
Horse, 239, 250, 271.
Hot Springs, 22.
Hudson Period, 120.
Hyena, 232.

Iceberg, 217.
Ichthyosaur, 173.
Iguanodon, 181.
Igneous Rocks, 26, 59.
Infusorial Earth, 48.
Iron Epoch, 250.
Ironstone, 59.
Irish Elk, 231.
Isinglass, 54.

Jasper, 45.

Jointed Structure, 81.

Jurassic, 167.

INDEX.

279

Kaolin, 54.

Kitchen Middens, 247.

Labradorite, 53.

Lafiyrinthodon, 183.

Laelaps, 192.

Lake Bottom, 81.

Lake Dwellings, 349.

Lake Superior, 113.

Lamellibranch, 141.

Lamina, 78.

Laurentian Mountains, 103.

Lava, 65.

Lepidodendron^ 157.

Lias, 168.

Limestone, 49, 58.

Lingula, 110.

Lithological Geology, 35.

Loess, 237.

Loraine Shales, 120.

Lower Magnesian Limestone, 110.

Mammoth Cave, 153.

Mammoth, 225.

Man, Coming of, 243.

Map of Eozoic Time, 100.

Map of Mesozoic Time, 168.

Map of Cenozoic Time, 195.

Marble, 51, 75.

Marble, Carrara, 67.

Marl, 50.

Marcellus Shale, 140.

Mastodon, 228.

Medina Group, 123.

Megalosaur, 182.

Megatherium, 229.

Mesozoic Time, 166.

Metal Age, 248.

Metamorphism, 66, 88, 164.

Metamorphic Rocks, 66.

Methods of Geological Study, 23.

Mica, 54.

Mica Schist, 74.

Millstone Grit, 154.

Miocene, 196.

Montmorency Falls, 104.

Mound Limestone, 124.

Mountains, 103.

Mollusks, 109.

Mosaic Account, 19, 105, 114, 238.

Nature, Uniformity of, 23-
Nebular Hypothesis, 17.

Niagara Limestone, 124.
Nummulitic Limestone, 198.

Obsidian, 66.

Offsets, 80.

Old Red Sandstone, 135.

Oneida Epoch, 123.

Onondaga Group, 139.

Onyx, 44.

OOlite, 50, 168.

Opal, 45.

Oriskany Period, 130.

Orthoceratite, 118.

Ostrea Marshii, 170.

Outcrop, 77.

Oyster, 170.

Paleozoic Time, 106.
Paleotherium, 203.
Paradoxides, 109.
Pentamerus, ]29.
Permian, 162.
Phacops bufo, 143.
Pine Barrens, 197.
Plaster, 52.
Plesiosaur, 177.
Pliocene, 196.
Porphyry, 60.
Post-Tertiary, 207.
Potsdam, 109.
Portage Group, 143.
Primeval Man, 243.
Pterodactyle, 178.
Pterichthys, 136.
Pudding-stone, 58.
Pumice, 66.
Pyroxene, 55.

Quartz, 40.
Quartzite, 75.
Quaternary Epoch, 207.
Quincy Granite, 74.

Radiates, 112.
Ramphorhynchus, 183.
Reindeer Epoch, 245.
Rhizopods, 102, 188.
Rhinoceros, 239.
Rocky Mountains, 122.
Rocks, Classification of, 57.
Rocks, Composition of, 40.
Rocks, Metamorphic, 66. .
Rocks, Sedimentary, 57.
Rocks, Structure of, 75.

880

INDEX.

Rocks, Stratified, 57, 76.
Rocks, Trap, 59.
Rocks, Unstratified, 59, 85.
Rocks, Volcanic, 65.

Salina Period, 127.
Salt Springs, 128.
Salt Beds, 186.
Sand, 46.
Sand Dunes, 238.
Sandstone, 57.
Sapphire, 49.
Sard, 43.
Satin Spar, 53.

Scenic Description, 20, 58, 60, 66, 70,
73, 74, 106, 132, 145, 161, 192, 239.
Schoharie Grit, 138.
Scoria, 66.

Sculptured Rocks, 114.
Sea-weeds, 106, 117.
Sea-pens, 121.
Sedimentary Rocks, 24, 57.
Selenite, 53.
Septaria, 83.
Serpentine, 56.
Shale, 58.

Shawangunk (Shong'-gum) Grit, 123.
Sigillaria, 157.
Silica, 40.
Silicates, 53.
Silurian Age, 107.
Sink-holes, 153.
Siphuncle, 120.
Slate, 75, 85.

Solenhofen Limestone, 169.
Soapstone, 55.
Spirifer arenosus, 131.
Spirifer mucronatus, 141.
Stalactites, 50.
Stalagmites, 50.

Steatite, 55.

St. Peter's Sandstone, 115.

Stone Age, 244.

Stratified Rocks, 57.

Stratum, 78.

Subcarboniferous Period, 152.

Syenite, 74.

Talc, 55.

Talcose Schist, 75.
Tentaculite, 129.
Tertiary Period, 196.
Terrace Epoch, 221.
Theory, Value of a, 252.
Titanotherium, 205.
Touchstone, 45.
Tourmaline, 56.
Trap-rock, 59.
Trachyte, 65.
Travertine, 49.
Trenton Period, 115.
Trilobite, 111.
Triassic Period, 167.
Tufa, 49.

Tully Limestone, 140.
Turtles, 191.

Uniformity of Nature, 23, 132.
Upper Helderberg Period, 138.
Utica Slate, 120.

Veins, 86.
Verd-antique, 51.

Water Lime Group, 128.
Wealden, 168.

Xiphodon, 203.
Zeuglodon, 202.

Atoll with its fringe of ooooanut trees and la«oon within,

THE NATIONAL SERIES OF STANDARD SCHOOL-BOOKS.

BARNES'S ONE-TERM HISTORY
SERIES.

Brief History of the United
States.

This is probably the MOST ORIGINAL SCHOOL-BOOK pub-
lished for many years, in any department. A few of it?
claims are the following : —

1. Brevity. — The text is complete for grammar school
or intermediate classes, in 290 12mo pages, large type.
It may readily be completed, if desired, in one term of
study.

2. Comprehensiveness. — Though so brief, this book
contains the pith of all the wearying contents of the larger
manuals, and a great deal more than the memory usually
retains from the latter.

3. Interest has been a prime consideration. Small

books have heretofore been bare, full of dry statistics, unattractive. This one is
charmingly written, replete with anecdote, and brilliant with illustration.

4. Proportion of Events. — It is remarkable for the discrimination with which
the different portions of our history are presented according to their importance. Thus
the older works, being already large books when the Civil War took place, give it less
space than that accorded to the Revolution.

5. Arrangement. — In six epochs, entitled respectively, Discovery and Settlement,
the Colonies, the Revolution, Growth of States, the Civil War, and Current Events.

6. Catch Words. — Each paragraph is preceded by its leading thought in promi-
nent type, standing in the student's mind for the whole paragraph.

7. Key Notes. — Analogous with this is the idea of grouping battles, &c., about
some central event, which relieves the sameness so common in such descriptions, and
renders each distinct by some striking peculiarity of its own.

8. Fopt-Notes. — These are crowded with interesting matter that is not strictly a
part of history proper. They may be learned or not, at pleasure. They are certain
in any event to be read.

9. Biographies of all the leading characters are given in full in foot-notes.

10. Maps. — Elegant and distinct maps from engravings on copper-plate, and beauti-
fully colored, precede each epoch, and contain all the places named.

11. Questions are at the back of the book, to compel a more independent use of the
text. Both text and questions are so worded that the pupil must give intelligent
answers IN HIS OWN WORDS. " Yes " and " No " will not do.

THE NATIONAL SERIES OF STANDARD SCHOOL-BOOKS.

HISTORY — Continued.

12. Historical Recreations. — These are additional questions to test the student's
knowledge, in review, as: "What trees are celebrated in our history?" "When
did a fog save our army?" "What Presidents died in office?" "When was th«
Mississippi our western boundary?" "Who said, 'I would rather be right than
President ' ? " &c.

13. The Illustrations, about seventy in number, are the work of our best artists
and engravers, produced at great expense. They are vivid and interesting, and mostly
upon subjects never before illustrated in a school-book.

14. Dates. — Only the leading dates are given in the text, and these are so associated
as to assist the memory, but at the head of each page is the date of the event first
mentioned, and at the close of each epoch a summary of events and dates.

15. The Philosophy of History is studiously exhibited, the causes and effects
of events being distinctly traced and their inter-connection shown.

16. Impartiality. — All sectional, partisan, or denominational views are avoided.
Facts are stated after a careful comparison of all authorities without the least prejudice
or favor.

17. Index. — A verbal index at the close of the book perfects it as a work of reference.
It will be observed that the above are all particulars in which School Histories have

been signally defective, or altogether wanting. Many other claims to favor it shares in
common with its predecessors.

TESTIMONIALS.

From PROF. WM. F. ALLEN, State Uni-
versity of Wisconsin.

"Two features that I like very much
are the anecdotes at the foot of the page
and the ' Historical Recreations' in the
Appendix The latter, I think, is quite
a new feature, and the other is very well
executed."

From HON. NEWTON BATEMAN, Superin-
tendent Public Instruction, Illinois.
"Barnes's One-Term History of the
United States is an exceedingly attrac-
tive and spirited little book. Its claim
to several new and valuable features seems
well founded. Under the form of six well-
defined epochs, the history of the United
States is traced tersely, yet pithily, from
the earliest times to the present day. A
good map precedes each epooh, wlrereby
the history and geography of the period
may be studied together, as they always
should be. The syllabus of each paragraph
is made to stand in such bold relief, by
the use of large, heavy type, as to be of
much mnemonic value to the student. The
book is written in a sprightly and pi-
quant style, the interest never flagging
from beginning to end, — a rare and diffi-
cult achievement in works of this kind."

From HON. ABNEB J. PHIPPS, Superin-
tendent Schools, Lewiston, Maine.
" Barnes's History of the United States

has been used for several years in the
Lewiston schools, and has proved a very
satisfactory work. I have examined the
new edition of it."

From HON. E. K. BUCHELL, City Superin-
tendent Schools, Lancaster, Pa.

" It is the best history of the kind I have
ever seen."

From T. J. CHARLTON, Superintendent

Public Schools, Vincennes, Ind.
"We have used it here for six years,
and it has given almost perfect satisfac-
tion. . . . The notes in fine print at the
bottom of the pages are of especial value."

From PROF. WM. A. MowRy, E. $• C.
School, Providence, R. I.

" Permit me to express my high appre-
ciation of your book. I wish all text-
books for the young had equal merit."

From HON. A. M. KEILEY, City Attorney,
Late Mayor, and President of the School
Soard, City of Richmond, Va.
" I do not hesitate to volunteer to you
the opinion that Barnes 's History is en-
titled to the preference in almost every
respect that distinguishes a good school-
book. . . . The narrative generally exhibits
the temper of the judge ; rarely, if ever,
of the advocate."

THE NATIONAL SERIES OF STANDARD SCHOOL-BOOKS.

A Brief History of An-
cient Peoples.

With an account of their monuments,
literature, and manners. 340 pages.
12mo. Profusely illustrated.

In this work the political history,
which occupies nearly, if not all,
the ordinary school text, is condensed
to the salient and essential facts, in
order to give room for a clear outline
of the literature, religion, architecture,
character, habits, &c., of each nation.
Surely it is as important to knowsome-
tff about Plato as all about Caesar,
and to learn how the ancients wrote
their books as how they fought their
battles.

The chapters on Manners and Cus-
toms and the Scenes in Real Life repre-
sent the people of history as men and
women subject to the same wants, hopes
and fears as ourselves, and so bring the distant past near to us. The Scenes, which are
intended only for reading, are the result of a careful study of the unequalled collections of
monuments in the London and Berlin Museums, of the ruins in Rome and Pompeii, and
of the latest authorities on the domestic life of ancient peoples. Though intentionally
written in a semi-romantic style, they axe accurate pictures of what might have occurred,
and some of them are simple transcriptions of the details sculptured in, Assyrian
alabaster or painted on Egyptian walls.

THE NATIONAL SERIES OF STANDARD SCHOOL-BOOKS.

HISTORY — Continued.

The extracts made from the sacred books of the East are not specimens of their style
and teachings, but only gems selected often from a mass of matter, much of which would
be absurd, meaningless, and even revolting. It has not seemed best to cumber a book
like this with selections conveying no moral lesson.

The numerous cross-references, the abundant dates in parenthesis, the pronunciation
of the names in the Index, the choice reading references at the close of each general
subject, and the novel Historical Recreations in the Appendix, will be of service to
teacher and pupil alike.

Though designed primarily for a text-book, a large class of persons — general readers,
who desire to know something about the progress of historic criticism and Lhe recent
discoveries made among the resurrected monuments of the East, but have no leisure to
read the ponderous volumes of Brugsch, Layard, Grote, Mommsen, and Ihne — will find
this volume just what they need.

From HOMER B. SPRAGUE, Head Master
Girls' High School, West Newton, St., Bos-
ton, Mass.
" I beg to recommend in strong terms

the adoption of Barnes's 'History of

Ancient Peoples ' as a text-book. It is
about as nearly perfect as could be
hoped for. The adoption would give
great relish to the study of Ancient
History."

HE Brief History of France.

By the author of the " Brhf United States,"
with all the attractive feattires of that popu-
lar work (which see) and new ones of its own.
It is believed that the History of France
has never before been presented in such
brief compass, and this is effected without
sacrificing one particle of interest. The book
reads like a romance, and, while drawing the

, , . student by an irresistible fascination to his

task, impresses the great outlines indelibly upon the memory.

THE NATIONAL SERIES OF STANDARD SCHOOL-BOOKS.

DR. STEELE'S ONE-TERM SERIES,
IN ALL THE SCIENCES.

Steele's i4-Weeks Course in Chemistry.
Steele's i4-Weeks Course in Astronomy.
Steele's i4-Weeks Course in Physics.
Steele's i4-Weeks Course in Geology.
Steele's i4-Weeks Course in Physiology.
Steele's i4-Weeks Course in Zoology.
Steele's i4-Weeks Course in Botany.

Our text-books in these studies are, as a general thing, dull and uninteresting.
They contain from 400 to 600 pages of dry facts arid unconnected details. They abound
in that which the student cannot learn, much less remember. The pupil commences
the study, is confused by the fine print and coarse print, and neither knowing exactly
what to learn nor what to hasten over, is "crowded through the single term generally
assigned to each branch, and frequently comes to the close without a definite and exact
idea of a single scientific principle.

Steele's " Fourteen-Weeks Courses " contain only that which every well-informed per-
son should know, while all that which concerns only the professional scientist is omitted.
The language is clear, simple, and interesting, and the illustrations bring the subject
within the range of home life and daily experience. They give such of the general
principles and the prominent facts as a pupil can make familiar as household words
within a single term. The type is large and open ; there is no fine print to annoy ;
the cuts are copies of genuine experiments or natural phenomena, and are of fine
execution.

In fine, by a system of condensation peculiarly his own, the author reduces each
branch to tlie limits of a single term of study, while sacrificing nothing that is essential,
and nothing that is usually retained from the study of the larger manuals in common
use. Thus the student has rare opportunity to economize his time, or rather to employ
that which he has to the best advantage.

A notable feature is the author's charming "style," fortified by an enthusiasm over
his subject in which the student will not fail to partake. Believing that Natural
Science is full of fascination, he has moulded it into a form that attracts the attention
and kindles the enthusiasm of the pupil.

The recent editions contain the author's " Practical Questions " on a plan never
before attempted in scientific text-books. These are questions as to the nature and
cause of common phenomena, and are not directly answered in the text, the design
being to test and promote an intelligent use of the student's knowledge of the foregoing
principles.

Steele's Key to all His Works.

This work is mainly composed of answers to the Practical Questions, and solutions of the
problems, in the author's celebrated " Fourteen-Weeks Courses " in the several sciences,
with many hints to teachers, minor tables, &c. Should be on every teacher's desk.

Prof. J. Dorman Steele is an indefatigable student, as well as author, and his books
have reached a fabulous circulation. It is safe to say of his books that they have
accomplished more tangible and better results in the class-room than any other ever
offered to American schools, and have been translated into more languages for foreign
schools. They are even produced in raised type for the blind.

THE NATIONAL SERIES OF STANDARD SCHOOL-BOOKS.

THE NEW GANOT.

Introductory Course of Natural Philosophy.

This book was originally edited from Ganot's " Popular Physics," by William G.
Peck, LL.D., Professor of Mathematics and Astronomy, Columbia College, and of
Mechanics in the School of Mines. It has recently been revised by Levi S. Bur-
bank, A. M., late Principal of Warren Academy, Woburn, Mass., and James I. Hanson,
A.M., Principal of the High School, Woburn, Mass.

Of elementary works those of M. Ganot stand pre-eminent, not only as popular
treatises, but as thoroughly scientific expositions of the principles of Physics. His
" Traite de Physique " has not only met with unprecedented success in France, but has
been extensively used in the preparation of the best works on Physics that have been
issued from the American press.

In addition to the "Traite de Physique," which is intended for the use of colleges
and higher institutions of learning, M. Ganot published this more elementary work,
adapted to the use of schools and academies, in which he faithfully preserved the
prominent features and all the scientific accuracy of the larger work. It is charcter-
ized by a well-balanced distribution of subjects, a logical development of scientific
principles, and a remarkable clearness of definition and explanation. In addition, it is
profusely illustrated with beautifully executed engravings, admirably calculated to
convey to the mind of the student a clear conception of the principles unfolded. Their
completeness and accuracy are such as to enable the teacher to dispense with much of
the apparatus usually employed in teaching the elements of Physical Science.

After several years of great popularity the American publishers have brought this
important book thoroughly up to the times. The death of the accomplished educator,
Professor Burbank, took place before he had completed his work, and it was then
taken in hand by his friend, Professor Hanson, who was familiar with his plans, and
has ably and satisfactorily brought the work to completion.

The essential characteristics and general plan of the book have, so far as possible,
been retained, but at the same time many parts have been entirely rewritten, much
new matter added, a large number of new cuts introduced, and the whole treatise
thoroughly revised and brought into harmony with the present advanced stage of sci-
entific discovery.

Among the new features designed to aid in teaching the subject-matter are the
summaries of topics, which, it is thought, will be found very convenient in short
reviews.

As many teachers prefer to prepare their own questions on the text, and many do not
have time to spend in the solution of pi-oblems, it has been deemed expedient to insert
both the review questions and problems at the end of the volume, to be used or not at
the discretion of the instructor.

From the Churchman.

" No department of science has under-
gone so many improvements and changes
in the last quarter of a century as that of
natural philosophy. So many and so im-
portant have been the discoveries and
inventions in every branch of it that
everything seems changed but its funda-
mental principles. Ganot has chapter
upon chapter upon subjects that were not
so much as known by name to Olmsted ;
and here we have Ganot, first edited by
Professor Peck, and afterward revised by
the late Mr. Burbank and Mr. Hanson. No
elementary works upon philosophy have
been superior to those of Ganot, either as
popular treatises or as scientific exposi-
tions of the principles of physics, and
his ' Traite de Physique ' has not only had
a great success in France, but has been
freely used in this country in the prepa-
ration of American books upon the sub-

jects of which it treats. That work was
intended for higher institutions of learn-
ing, and Mr. Ganot prepared a more
elementary work for schools and acade-
mies. It is as scientifically accurate as
the larger work, and is characterized by
a logical development of scientific princi-
ples, by clearness of definition and expla-
nation, by a proper distribution of sub-
jects, and by its admirable engravings.
We here have Ganot's work enhanced in
value by the labors of Professor Peck and of
Messrs. Burbank and Hanson, and brought
up to our own times. The essential char-
acteristics of Ganot's work have been re-
tained, but much of the book has been
rewritten, and many new cuts have been
introduced, made necessary by the prog-
ress of scientific discovery. The short
reviews, the questions on the text, and
the problems given for solution are desir-
able additions to a work of this kind, and
will give the book increased popularity. "

14 DAY USE

RETURN TO DESK FROM WHICH BORROWED

EARTH SCIENCES LIBRA

This book is due on the last date stamped below, or

on the date to which renewed.
Renewed books are subject to immediate recall.

LD 2]-40m-5,'65
(F4308slO)476

General Library

University of California

Berkeley

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v -€/•> 1. 1 • ul

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