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London, Published by John Murray, Albemarle Street dprid 1834

PRINCIPLES

OF

GEOLOGY:

BEING
AN INQUIRY HOW FAR THE FORMER CHANGES OF

THE EARTH’S SURFACE

ARE REFERABLE TO CAUSES NOW IN OPERATION.

BY
CHARLES LYELL, Esa. F.R.S.

PRESIDENT OF THE GEOLOGICAL SOCIETY OF LONDON,

ee

“ Amid all the revolutions of the globe, the economy of Nature has been
uniform, and her laws are the only things that have resisted the general
movement. The rivers and the rocks, the seas and the continents, haye been
changed in all their parts; but the laws which direct those changes, and the
rules to which they are subject, have remained invariably the same.”

Prayrair, Illustrations of the Huttonian Theory, § 374.

IN FOUR VOLUMES.

VOL. I.

THE FIFTH EDITION.

LONDON: |
JOHN MURRAY, ALBEMARLE STREET.
1837.

Lonpon:

Printed by A. SPOTTISWOODE,
New-Street.Square.

PREFACE.

Tur original MS. of the Principles of Geology

was delivered to the publisher in 1827; but the
greater portion of it was then in an unfinished
state, the chapters on the early history of Geology,
and those on “the Inorganic Causes of Change,”
being the only ones then nearly ready for the press.
The work was at that time intended to form two
octavo volumes, which were to appear in the course
of the year following. Their publication, however,
was delayed by various geological tours which I
made in the years 1828, 1829, 1830, and 1831, in
France, Italy, Sicily, and Germany. The follow-
ing were the dates when the successive volumes
and editions finally appeared : —

Ist Vol. in octavo - - Jan. 1830.
2d Vol. do. - - Jan. 1832.
Ist Vol. 2d edition in octavo 1832.
2d Vol. 2d edition do. Jan. 1833.
3d Vol. ist edition do. May 1833.
New edition (called the 3d) of the

whole work in 4 vols. 12mo. May 1834.
4th edition, 4 vols. 12mo. - June 1835,

Ae

PREFACE.

I have acknowledged on former occasions the
valuable assistance afforded me by several of my
friends in the execution of this work, and have
especially returned my thanks to Mr. Murchison,
Mr. Broderip, Dr. Fitton, Mr. Lonsdale, and Capt.
Basil Hall, for their zealous co-operation, and for
the corrections and improvements which were
adopted at their suggestion. |

In the Prefaces to the Third and Fourth Editions,
I gave lists of the places where new matter had
been introduced, or where opinions expressed in
former Editions had been modified or renounced.
I shall now again subjoin a similar list for the sake
of those readers who have already studied this
work, but who may wish to refer at once to the

additions and corrections now made for the first

time.

List of the principal Alterations and Additions in the
Fifth Edition as compared to the Fourth.

Vol. I.
Deluge of the Chinese - = i ie p. 10
Legend of the Seven Sleepers - = £ 119
Humboldt on preservation of animals in frozen mud 154
Stranding of icebergs on west coast òf Iceland - 173
Raised beaches in Carlingford. Bay, Ireland i 215
Omission of remarks on the origin of the valleys of the
Moselle and Meuse - n 5 3 a
Account of Edmonstone Island corrected £ = 360

PREFACE. yY

Vol. I.
Arago on causes of currents, and on relative level of the
Red Sea and Mediterranean - - - - p. 387

On the formation of Shingle beaches z = SOs

Voi. II.
Dr. Daubeny on a volcanic band across the Italian

peninsula - - - a x A 57
Theory of elevation-craters recast, with many additions
and new illustrations - 2

= ~

Account of the earthquake in Chili, February 1835, added ;
with Map of Chili and plan of the Harbour of Concep-
tion 5 4 = 3 ;

Dr. Meyen on proofs of elevation of land in Chili, 1822 -
On the effects of earthquakes in the excavation of valleys,
recast - = = z - 3

Von Buch on the elevation of Scandinavia =
Account of the subsidence of Greenland enlarged

Vol. III.
Sir John Herschel on the vegetation of seeds after exposure

to great heat - - - - = 14
‘Dr. Beck on the great range of some species of testacea - 56
Erman on the level of the Caspian - - - 126
Account of Submarine Forests, transferred to this place

from Chapter xvi. - - - = - 226

Vol. IV.
Loess of the Valley of the Rhine, the whole recast with
additions - - - z = - 29
Slope of recent strata in the modern delta of the Kander
in Lake of Thun - - - - - 69
Crag of Norfolk and Suffolk, and overlying deposit. The
whole of this chapter recast ~ - - - 71
M. Dufrénoy on the tertiary strata of the basin of the
Gironde 5 > s 121, 124
Note on the latest opinions respecting an alleged difference
of level between the Caspian and Black Seas - - 202
Professor Sedgwick and Sir J. Herschel on the causes
of the cleavage of rocks a z - 357 to 359

A-S

PREFACE.

New Wood Cuts in the Fifth Edition.

Vol: I.
p. 143
149

1 Pleurotoma rotata
2 Map of Siberia - =
3 Iceberg seen off Cape
of Good Hope -= 178

4 Shakspeare’s Cliff - 419
Vol. II.

5 Section of Jorullo - 134
6 Diagrams to illustrate
the elevation-crater
theory - -

7 Plan of the Isle of

Palma = á

154

155
2- Diagrams to illustrate -171
of the trtion-crer| ib.
107 theory - - C176
11 Map of Chili - - 184
12 Map of Harbour of
Conception - -
Map of Calabria -
Map of Sweden and
the Baltic - - 290
Vol. TIT.
Meandrina labyrinthica 276
Astrea dipsacea - ib
Madrepora muricata 277
Caryophyllia fastigiata ib.
Porites clavaria - 1b.
Oculina hirtella

186

13 211

Vol. IV.

View of worn lime-

stone columns

Niapisca island
Succinea elongata
Pupa muscorum
Helix plebeium
Catillus Cuvieri

in

26
AT
28
29
30
31
32
33
34
35

36
37
38

Vol.

Crania Parisiensis p.

Plagiostoma Hoperi
P. spinosum - -
Terebratula Defrancii
Ostrea carinata - æ
Terebratula octoplicata
T. pumilus - r
T. carnea = 2
Ostrea vesicularis ~
Belemnites mucrona-

tus - - wa =

Baculites Faujasii -
B. anceps 2 =
Ammonites rhotoma-
gensis - - -
Beloptera belemnitoi-
dea s = x
Hippurites . bioculata
and H. radiosa -
Terebratula lyra -
Pecten 5-costatus -
Turrilites costatus p.
Cypris spinigera -
C. Valdensis -
C. tuberculata -
Gryphæa virgula -
Ostrea deltoidea =
Section of Nerinca
hieroglyphica -
Cast of Diceras arie-
tina - - -
Terebratula spinosa -
Pholadomya fidicula
Belemnites hastatus
Gryphæa incurva -
Nautilus truncatus -

PREFACE, vil

Vol. IV. Vol. IV.
56 Hybodus reticulatus p. 292 | 60 O. giganteum - p. 295
57 Acrodus nobilis - ib | 61 Calymene Blumenba-
58 Avicula socialis Jean ies Chit = = -2 299

59 Orthoceras laterale - 295 | 69 Asaphus Buchii - 16,

Glossary. — Being informed by several readers
of my Third Edition, that they only discovered
the Glossary when they arrived at the last vo-
lume, I have in this, as in the Fourth Edition,
appended it to the end of the first volume, in order
that it may be conveniently referred to by those

who are beginning the work; and that it might

not be confounded with the Index at the end of
the fourth volume.

A general view or summary of the contents of
this work cannot fail to be useful in pointing out
more clearly the course of reasoning adopted, and
the order in which the different subjects are
treated. I therefore hope that the student, by
referring from time to time to the subjoined sum-
mary, will more easily understand the plan of the
whole, and the bearing on geology of several
digressions which I have introduced on collateral
topics, especially on certain departments of na-
tural history.

PREFACE.

GENERAL VIEW OR SUMMARY OF THE
PRINCIPLES OF GEOLOGY.

After some observations on the nature and
objects of Geology (Chap. I. Vol. I.), a sketch is
given of the progress of opinion in this. science,
from the times of the earliest known writers to
our own days (Chaps. II. HI. IV.). From this
historical sketch it appears that the first cultivators

of geology indulged in many visionary theories,
the errors of which are referred chiefly to one
common source, — a prevailing persuasion that the
ancient causes of change were different, both as
regards their nature and energy, to those now in
‘action. In other words, it was supposed that the
causes by which the crust of the earth, and its
habitable surface, were modified at remote pe-
riods, were almost entirely distinct from the oper-
ations by which the surface and crust of the
planet are now undergoing a gradual change.
The prejudices which led to this assumed dis-
cordance of ancient and modern causes are next
considered: (Chap. V. to p. 125. Vol. I.), and it is
contended that neither the imagined universality
of certain sedimentary formations (Chap. V.), nor
the different climates which appear to have formerly
pervaded the northern hemisphere (Chaps. VI.

i PREFACE. ix
VII. VIIL), nor the alleged progressive develop-
ment of organic life as inferred from the study of
fossil remains (Chap. IX.), lend any solid support
to the assumption.

The numerous topics of general interest brought
under review in discussing this fandamental ques-
tion are freely enlarged upon, in the hope of
stimulating curiosity; and the author is aware
that in endeavouring to attain this object, he has
occasionally carried the beginner beyond his depth.
It is presumed, however, that the reader will un-
derstand enough to be convinced that the forces
formerly employed to remodel the crust of the
earth were the same in kind and energy as those
now acting: or, at least, he will perceive that the
opposite hypothesis is very questionable; and if
so, he will enter upon the study of the two
treatises which follow on the Changes now in
progress in the Organic and Inorganic World
(Books II; and IIL) with a just sense of the im-
portance of their subject matter, and their direct

bearing on Geology.

The first of these treatises, or that relating to

the changes known to have taken place in the

inorganic creation within the historical era, s

divided into two parts. In the first, an account is

given of the observed effects of aqueous causes,
A5

ee

x PREFACE.

such as rivers, springs, tides, and currents (Book II.
Chaps. I. to VIIL); in the second, the igneous
causes, such as the volcano and earthquake, and all
subterranean movements, are considered (Book II.
Chaps. IX. to XIX.).

The other treatise, or that on the changes of the
organic world, is also divided into two parts; the
first of which comprehends all questions relating
to the real existence and variability of species, and
the limits assigned to their duration (Chaps. I. to
XI. Book"III.) The second explains the pro-
cesses by which the remains of animals and plants
existing at any particular period may be preserved,
or become fossil (Chaps. XII. to XVIL.).

The object of the first of the divisions just men-
tioned may be stated more fully thus, —the author
begins by defining the term species, and combats
the notion that one species may be gradually con-
verted into another by insensible modifications in
the course of ages (Chaps. I. II. III. and IV.).
He then enters into a full examination of the

evidence regarded by him as conclusive in favour

of the limited durability of species; in proof of
which, he argues that the geographical distribu-
tion of species being partial, the changes inces-
santly going on in the animate and inanimate

world must constantly tend to their extinction

PREFACE. xi

(Chaps. V. to X.). Whether new species are
substituted from time to time for those which die
out, is a point on which no decided opinion is
offered; the data hitherto obtained being consi-
dered insufficient to determine the question. But
it is contended that if new species had been intro-
duced from time to time as often as others have
been lost, we should have no reason to expect to
be able to establish the fact during the limited
period of our observation (Chap. XI.).

The fourth and last book is occupied with the
description of geological monuments strictly so

called, the formations termed tertiary being first

more fully examined and classified, the secondary

and primary rocks being afterwards more briefly
alluded to. It appears that the materials which
compose the crust of the earth have acquired their
present form and arrangement in part from the
action of igneous, in part of aqueous causes; or
from the combined influence of both these agents,
the igneous having operated both upon and far
beneath the surface. It seems, also, that almost
all rocks have since the era of their formation
been moved, bent, and dislocated; and in some
cases upraised far above, and in others made to

sink down far below, the level at which they
originated.

l
j
|
Fi

SE eT es Att TT ELLIE LIE E

xii PREFACE.

Now the principal source from whence we are
enabled to draw such conclusions respecting the
nature of the solid materials of the earth, and the
changes which they have undergone, is a com-
parison of geological phenomena with the effects
previously known to have been produced in mo-
dern times by running water and subterranean
heat. Hence the utility of one of the preceding
treatises (Book II.) on aqueous and igneous causes,
in which it was shewn that strata are at present in
the course of formation by rivers, and marine cur-
rents, both in seas and lakes ; and that in several
parts of the world rocks have been rent, tilted,
and broken by modern earthquakes; or have been
heaved up above, or let down below, their former
level; also that volcanic eruptions have given rise to
mountain masses made up of scoriæ, and of stone
both porous and solid. It is also shewn in the
Fourth Book, that the class of rocks which are of
aqueous origin are not only characterized by
being divided into strata, but also by containing
within them very generally the remains of shells,
and of various animals and plants, which must
have been imbedded at the period of the deposi-
tion of the strata. In order to comprehend in
what manner such remains were buried in the

earth, we must have recourse to the processes now

PREFACE. XII

going on, by which certain individuals of existing
species become fossil, and this information has
been given in the Third Book. It also appears
in the Fourth Book that the fossil remains just
alluded to, have belonged for the most part to
species which have ceased to exist upon the
earth; and after studying the fossils of different
strata, we find proofs that many distinct assem-
blages of animals and plants have flourished in
succession on the globe. In every attempt to
reason on the causes of such remarkable changes,
we find it necessary to know how far the state of `
the organic world in our own times is fixed or
fluctuating; whether there is any reason to believe
that in the present course of nature the same spe-
cies last for indefinite periods, or whether some
are gradually giving place to others, which in their
turn are multiplying and extending their geogra-
phical range. These questions have also been
discussed in the first part of the Third Book;
after reading which, the student comes in a great
degree prepared to follow the views and specula-

tions of the author on the laws by which the ex-

tinction and successive disappearance of species
may be governed.

From these remarks it will be seen that a

study of systematic treatises on the recent changes

XIV PREFACE.

of the organic and inorganic world afford a good

preliminary exercise for those who desire to in-
terpret geological monuments. They are thus
enabled to proceed from the known to the un-
known, or from the observed effects of causes now
in action to the analogous effects of the same or
similar causes which have acted at remote periods.
It was necessary to dwell thus fully on the con-
nection of the Second and Third Books with the
Fourth, because the relation of these parts of the
work to each other is the least obvious. In order
to comprehend the plan of other parts, it will be
sufficient to peruse the following abridged Table

of Contents.

London, October, 1836.

ABRIDGED TABLE OF THE CONTENTS

OF THE WHOLE WORK.

Vol. I.

Boox T. Cmar. I. Objects and Nature of Geology - pi
II. III. IV. Historical Sketch of the Progress of
Geology - à =
V. Theoretical Errors which have retarded

the Progress of Geology -

VI. VII. VIII. One of these, the assumed Discordance
of the ancient and existing Causes of

Change, controverted—Climate -

- The same Question considered in refer-

ence to the Theory of the Progressive

Development of Organic Life -

Boox II. Cuar. I. Changes of the Inorganic World now in

Progress — Aqueous Causes — Ac-

tion of running Water - -

© Rivers — Floods - - -

- Phenomena of Springs - -

- Deposits in Deltas of Lakes and inland

Seas = B P a

- Oceanic Deltas - - =

VI. VII. Tides and Currents — Destroying Effects
Vol.

VIII. Tides and Currents — Reproductive

Effects -~ - - =

IX. Igneous Causes — Volcanic Regions -

X. XI. Volcanic District of Naples - %

XII. Etna— Its modern Lavas -

xvi

Boox II.
Cuar. XIII.

XIV.
XV.
XVI.
XVII.

XVIII.
XIX.

Boox III. Cu. I.

doks

EVE

V. VI. VII.
VIIE IX.

X.
XI.

XII.

CONTENTS.

Vok: LE

Lancerote — Submarine Volcanos —

Theory of Elevation Craters
Earthquakes of the last Fifty Years -
Earthquake of Calabria in 1783 -
Earthquakes, continued — Temple of

Serapis - - - -
Elevation and Subsidence of Land with-

out Earthquakes - - -
Causes of Volcanic Heat ~ -
Causes of Earthquakes ~ =

Changes of the Organic World now in
Progress — Reality of Species -
Theory of Transmutation of Species
untenable - - -
Limits of the Variability of Species -
Hybrids - - = -

Geographical Distribution of Species -
Changes in the Animate World, which
tend to the Extinction of Species -

Changes in the Inorganic World, tend-
ing to the Extinction of Species -
Whether the Extinction and Creation

of Species can now be in Progress -
Modifications in Physical Geography
caused by Plants, the inferior Ani-
mals, and Man - £ =
How Plants and Animals become Fossil
in Peat, Blown Sand, and Volcanic
Matter - - £

. Burying of Fossils in Alluvial Deposits

XV.

XVI.

and Caves - - 3
Imbedding of Organic Remains in the
Deposits of Seas and Lakes 3
How the Remains of Man and his
Works are becoming Fossil beneath
the Waters - È =

- p.

138
181
210

248

286

307
331

- Boox III.

Cuar. XVII.

XVIII.

- Boox IV. Cu, I.

II.

CONTENTS. XVII

Vol. III.
How Freshwater and Marine Plants
and Animals are becoming Fossil in
Subaqueous Strata - - - p. 258
Formation of Coral Reefs 2 ao Oe

On the Connexion of the Second and
Third Books with the Fourth EOS
General Arrangement of Materials in
the Earth’s: Crust, and Rules for
determining the relative Ages of
Rocks - = cS resi

- Discovery of Tertiary Groups of succes-

sive Periods - - - $32

- Different Circumstances under which

Vs

VI.

VII. VIII.
IDS.

the Secondary and Tertiary Form. .

ations may have originated way egak
Subdivision of Tertiary Formations con-

sidered chronologically = SIN

Newer Pliocene Formations — Sicily 382

Rocks of the same Age in Etna - 397
Changes since the Formation of the
Newer Pliocene Strata in Sicily - 433

Vol. IV.

. Marine and Volcanic Newer Pliocene

Formations =

. Freshwater and Alluvial of the same

Period = =

- Older Pliocene Formations - -

Crag of Norfolk and Suffolk - -

- Volcanic Rocks of the Older Pliocene

Period > = a s

- Miocene Formations — Marine

Alluvial — Freshwater — Volcanic
Eocene Formations — Freshwater

— Paris Basin
Volcanic Rocks -
Formations of different Coun-

tries and of England = *

xviii

Boox IV.

CONTENTS.

Vol. IV.

Cu. XXI. XXII. Origin of the English Eocene Form-

XXITI.
XXIV.

XXV.
XXVI.

XXVII.

ations and Denudation of the Weald p. 220
Secondary Formations Š - 268
Analogy of the older Fossiliferous to

the Tertiary Strata a =
Relative Antiquity of Mountain’ Chains
On the Rocks commonly called Pri-

mary — Unstratified - -

On the same — Stratified = >

DIRECTIONS TO THE BINDER.

Frontispiece to face Title-page, Vol. I.

<P #09 S08'0'00:9'66'6 S A LLA T 800.0 060

BOOK I.

CHAPTER I.

Geology defined — Compared to History — Its relation to other
Physical Sciences — Not to be confounded with Cosmogony.

Grotocy is the science which investigates the suc-
cessive changes that have taken place in the organic
and inorganic kingdoms of nature : it inquires into the
Causes of these changes, and the influence which they
have exerted in modifying the surface and external
Structure of our planet.

By these researches into the state of the earth and
its inhabitants at former periods, we acquire a more
perfect knowledge of its present condition, and more
Comprehensive views concerning the laws now govern-
ing its animate and inanimate productions. When:we
study history, we obtain a more profound insight into
human nature, by instituting a comparisonbetween the
present and former states of society. We trace the
long series of events which have gradually led to the
actual posture of affairs; and by connecting effects with
their causes, we are enabled to classify and retain in
the memory a multitude of complicated relations—the
various peculiarities of national character — the dif-

VOL. I. B

Q GEOLOGY COMPARED TO HISTORY, [Book I,

ferent degrees of moral and intellectual refinement,
and numerous other circumstances, which, without
historical associations, would be uninteresting or im-
perfectly understood. As the present condition of
nations is the result of many antecedent changes, some
extremely remote and others recent, some gradual,
others sudden and violent, so the state of the natural
world is the result of a long succession of events ; and
if we would enlarge our experience of the present
economy of nature, we must investigate the effects of
her operations in former epochs.
We often discover with surprise, on looking back
into the chronicles of nations, how the fortune of
some battle has influenced the fate of millions of our
contemporaries, when it has long been forgotten by
the mass of the population. With this remote event
we may find inseparably connected the geographical
boundaries of a great state, the language now spoken
by the inhabitants, their peculiar manners, laws, and
religious opinions. But far more astonishing and un-
expected are the connections brought to light, when
we carry back our researches into the history of nature.
The form of a coast, the configuration of the interior
of a country, the existence and extent of lakes, valleys,
and mountains, can often be traced to the former pre-
valence of earthquakes and volcanos in regions which
have long been undisturbed. To these remote con-
vulsions the present fertility of some districts, the
sterile character of others, the elevation of land above
the sea, the climate, and various peculiaritie
distinctly referred. On the other hand, many distin-
guishing features of the surface may often be ascribed
to the operation, at a remote era, of slow and tranquil
causes—to the gradual deposition of sediment in a

S, may be

Ch. L] ITS RELATION TO OTHER PHYSICAL SCIENCES. 3

lake or in the ocean, or to the prolific increase of
testacea and corals.

To select another example, we find in certain
localities subterranean deposits of coal, consisting of
vegetable matter, formerly drifted into seas and lakes.
These seas and lakes have since been filled up, the
lands whereon the forests grew have disappeared or
changed their form, the rivers and currents which
floated the vegetable masses can no longer be traced,
and the plants belonged to species which for ages have
Passed away from the surface of our planet. Yet the
Commercial prosperity, and numerical strength of a
Nation, may now be mainly dependent on the local
distribution of fuel determined by that ancient state
of things.

Geology is intimately related to almost all the
physical sciences, as history is to the moral. An
historian should, if possible, be at once profoundly
acquainted with ethics, politics, jurisprudence, the
military art, theology; in a word, with all branches of
knowledge by which any insight into human affairs, or
into the moral and intellectual nature of man, can be
obtained. It would be no less desirable that a geolo-
gist should be well versed in chemistry, natural phi-
losophy, mineralogy, zoology, comparative anatomy,
botany ; in short, in every science relating to organic
and inorganic nature. With these accomplishments,
the historian and geologist would rarely fail to draw
correct and philosophical conclusions from the various
monuments transmitted to them of former occurrences.
They would know to what combination of causes ana-
logous effects were referable, and they would often
be enabled to supply, by inference, information con-
cerning many events unrecorded in the defective

B 2

4 ' GEOLOGY COMPARED TO HISTORY. [Book F.

archives of former ages. But as such extensive ac-
quisitions are scarcely within the. reach of any indi-
vidual, it is necessary that men who. have devoted
their lives to .different departments should unite their
efforts; and as the historian receives assistance from
the antiquary, and from those who have cultivated dif-
ferent branches of moral and political science, so the
geologist should avail himself of the aid of many na-
turalists, and particularly of those who have studied the
fossil remains of lost species of animals and plants.
The analogy, however, of the monuments consulted
in geology, and those available in history, extends no
farther than to one class of historical monuments, —
those which may be said to be wndesignedly com-
memorative of former events. The canoes, for ex-
ample, and stone hatchets found in- our peat bogs,
afford an insight into the rude arts and manners of the
earliest inhabitants of our island; the buried coin fixes
the date of the reign of some Roman emperor ; the
ancient encampment indicates the districts once occu-
pied by invading armies, and the former method of
constructing military defences: the Egyptian mummies
throw light on the art of embalming, the rites of
sepulture, or the average stature of the human race in
ancient Egypt. This class of memorials yields to no
other in authenticity, but it constitutes a small part
only of the resources on which the historian relies,
whereas in geology it forms the only kind of evidence
which is at our command. For this reason we must
not expect to obtain a full and connected account of
any series of events beyond the reach of history. But
the testimony of geological monuments, if frequently
imperfect, possesses at least the advantage of þeing
free from all suspicion of misrepresentation. We may
be deceived in the inferences which we draw, in the

Ch. 1.) GEOLOGY DISTINCT FROM COSMOGONY.* — §

same manner as we often mistake the nature and
import of phenomena observed in the daily course of
nature ; but our liability to err is confined to the inter-
pretation, and, if this be correct, our information is
certain.

It was long before the distinct nature and legitimate
objects of geology were fully recognized, and it was at
first confounded with many other branches of inquiry,
Just as the limits of history, poetry, and. mythology
were ill-defined in the infancy of civilization. Even in
Werner’s time, or at the close of the eighteenth century,
geology appears to have been regarded as little other
than a subordinate department of mineralogy; and
Desmarest included it under the head of Physical
Geography. But the most common and serious source
of confusion arose from the notion that it was the

business of geology to discover the mode in which the
earth originated, or, as some imagined, to study the
effects of those cosmological causes which were em-
ployed by the Author of Nature to bring this planet
out of a nascent. and chaotic state into a more perfect
and habitable condition. Hutton was the first who
endeavoured to draw a strong line of demarcation
between his favourite:science and cosmogony, for he
declared that geology was in nowise concerned “ with
questions as to the origin of things.”

An attempt will be made in the sequel of this work
to demonstrate that geology differs as widely from
cosmogony, as: speculations concerning the mode of
the first creation of man differ from history. But,
before entering more at large on this controverted
question, it will be desirable to trace the progress of
opinion on this: topic, from the earliest ages to the
commencement of the present century.

B 3

CHAPTER I.

HISTORICAL SKETCH OF THE PROGRESS OF GEOLOGY.

Oriental Cosmogony — Doctrine of the successive destruction
and renovation of the world— Origin of this doctrine —
Common to the Egyptians (p. 12.) —- Adopted by the Greeks
— System of Pythagoras—of Aristotle (p. 20.) — Dogmas
concerning the extinction and reproduction of genera and species

~ — Strabo’s theory of elevation by earthquakes (p. 24.) — Pliny
— Concluding Remarks on the knowledge of the Ancients,

Oriental Cosmogony.— Tue earliest doctrines of the
Indian and Egyptian schools of philosophy agreed in
ascribing the first creation of the world to an omni-
potent and infinite Being. They concurred also in
representing this Being, who had existed from all
eternity, as having repeatedly destroyed and repro-
duced the world and all its inhabitants. In the
“Institutes of Meni,” the sacred volume of the Hin-
doos, to which, in its present form, Sir William Jones
ascribes an antiquity of at least eight hundred and
eighty years before Christ, we find this system of the
alternate destruction and renovation of the world
proposed in the following remarkable verses : —

“The Being, whose powers are incomprehensible,
having created me (Menu) and this universe, again
became absorbed in the supreme spirit, changing the
time of energy for the hour of repose.

« When that power awakes, then has this world its
full expansion ; but when he slumbers with a tranquil
spirit, then the whole system fades away. .... For

Ch. IL] INSTITUTES OF MENU. 7

while he reposes as it were, embodied spirits endowed
with principles of action depart from their several
acts, and the mind itself becomes inert.”

Menù then describes the absorption of all beings
into the Supreme essence, and the Divine soul itself
is said to slumber, and to remain for a time immersed
in “the first idea, or in darkness.” He then proceeds
(verse fifty-seven), “ Thus that immutable power, by
waking and reposing alternately, revivifies and de-
stroys, in eternal succession, this whole assemblage of
loccmotive and immoveable creatures.”

It is then declared that there has been a long
succession of manwantaras, or periods, each of the
duration of many thousand ages, and —

« There are creations also, and destructions of worlds
innumerable: the Being, supremely exalted, performs
all this with as much ease as if in sport, again and
again, for the sake of conferring happiness.” *

The compilation of the ordinances of Ment was not
all the work of one author nor of one period, and to
this circumstance some of the remarkable inequalities
of style and matter are probably attributable. There
are many passages, however, wherein the attributes
and acts of the “ Infinite and Incomprehensible Being”
are spoken of with much grandeur of conception and
sublimity of diction, as some of the passages above
cited, though sufficiently mysterious, may serve to
exemplify. There are at the same time such puerile
conceits and monstrous absurdities in this cosmogony,
that some may be disposed to impute to mere accident
any slight approximation to truth, or apparent coin-

* Institutes of Hindoo Law, or the Ordinances of Menù, from
the Sanscrit, translated by Sir William Jones, 1796.
B 4

8 ' ORIENTAL COSMOGONY., [Book I.

cidence between the oricntal dogmas and observed
facts. This pretended revelation, however, was not
purely an effort of the unassisted imagination, nor in-
vented without regard to the opinions and observations
of naturalists. There are introduced into it certain
astronomical theories, evidently derived from observ-
ation and reasoning. Thus, for instance, it is declared
that, at the North Pole, the year was divided into a
long day and night, and that their long day was the
northern, and their night the southern course of the
sun; and to the inhabitants of the moon, it is said, one
day is equal in length to one month of mortals.* If
such statements cannot be resolved into mere conjec-
tures, we have no right to refer to mere chance the
prevailing notion, that the earth and its inhabitants
had formerly undergone a succession of revolutions
and catastrophes interrupted by long intervals of tran-
quillity.

Now there are two sources in which such a theory
may have originated. The marks of former convul-
sions on every part of the surface of our planet are
obvious and striking. The remains of marine animals
imbedded in the solid strata are so abundant, that they
may be expected to force themselves on the cbserv-
ation of every people who have made some progress in
refinement; and especially where one class of men
are expressly set apart from the rest for study and
contemplation.- If these appearances are once recog-
nized, it seems natural that the mind should conclude
in favour, not only of mighty changes in past ages,
but of alternate periods of repose and disorder ; —
of repose, when the fossil animals lived, grew, and

* Menu, Inst. c.i. 66, and 67.

a a aaan ac ee ee ON

Ch. 11] ORIENTAL COSMOGONY. 9

multiplied — of disorder, when the strata in which they
were buried became transferred from the sea to the
interior of continents, and were uplifted so as to form
Part of high mountain chains. , Those modern writers,
who are disposed to disparage the former intellectual
advancement and civilization of eastern nations, may
Concede some foundation of observed facts for the
Curious theories now under consideration, without in-
dulging in exaggerated opinions of the. progress of
science; especially as universal. catastrophes of the
world, and exterminations of organic beings, in the
Sense in which they were understood by the Brahmin,
are untenable doctrines.
We know that the Egyptian priests were aware,
not only that the soil beneath the plains of the Nile,
but that also the hills bounding the great valley, con-
tained marine shells*; and it could hardly have escaped
the observation of eastern philosophers, that some
Soils were filled with fossil remains, since so many
national works requiring extensive excavations were
€xecuted by oriental monarchs in very remote eras.
They formed canals and tanks on a magnificent scale,
and we know that in more recent times (the four-
teenth century of our era) the removal of soil neces-
sary for such undertakings brought to light geological
Phenomena, which attracted the attention of a people
less civilized than were many of the older nations of

the East.+

* Herodot. Euterpe, 12.

+ This circumstance is mentioned in a Persian MS. copy of
the historian Ferishta, in the library of the East India Company,
relating to the rise and progress of the Mahomedan empire in
India, procured by Colonel Briggs from the library of Tippoo

3 to]
Sultan in 1799; and has been recently referred to at some length

BS

10 ORIENTAL COSMOGONY. [Book I.

But although the Brahmins, like the priests of
Egypt, may have been acquainted with the existence
of fossil remains in the strata, it is possible that the
doctrine of successive destructions and renovations of
the world merely received corroboration from such
proofs; and that it may have been originally handed
down, like the religious traditions of most nations,
from a ruder state of society. The system may
have had its source in exaggerated accounts of those
partial, but often dreadful, catastrophes, which are
sometimes occasioned by particular combinations of
natural causes. Floods and volcanic eruptions, the
agency of water and fire, are the chief instruments of
devastation on our globe. We shall point out in the
sequel the extent of many of these calamities, re-
curring at distant intervals of time, in the present
course ef nature; and shall only observe here, that
they are so peculiarly calculated to inspire a lasting
terror, and are so often fatal in their consequences to
great multitudes of people, that it scarcely requires
the passion for the marvellous, so characteristic of
rude and half-civilized nations, still less the exuberant
imagination of eastern writers, to augment them into
general cataclysms and conflagrations,

The great flood of the Chinese, which their tra-
ditions carry back to the period of Yaou, something

by Dr. Buckland. — (Geol. Trans. 2d Series, vol, ij, part iii.
p. 389.) — It is stated that, in the year 762 (or 1360 of our era),
the king employed fifty thousand labourers in cutting through a
mound, so as to form a junction between the rivers Selima and
Sutluj; and in this mound were found the bones of elephants and
men, some of them petrified, and some of them resembling bone,
The gigantic dimensions attributed to the human bones show them
to have belonged to some of the larger pachydermata,

Ch, IL] ORIENTAL COSMOGONY. w

_ more than 2000 years before our eray has been iden-
tified by some persons with the universal deluge
described in the Old Testament ; but according to Mr.
Davis, who accompanied two of our embassies to
China, and who has carefully examined their written
accounts, the Chinese cataclysm is therein described as
interrupting the business of agriculture, rather than
as involving a general destruction of the human race.
The great Yu was celebrated for having “ opened
nine channels to draw off the waters,” which “ covered
the low hills and bathed the foot of the highest moun-
tains.” Mr. Davis suggests that a great derangement
of the waters of the Yellow River, one of the largest
in the world, might even now cause the flood of Yaou
to be repeated, and lay the most fertile and populous
plains of China under water. In modern times the
bursting of the banks of an artificial canal, itito which
a portion of the Yellow River has been turned, has
repeatedly given rise to the most dreadful accidents,
and is a source of perpetual anxiety to the govern-
ment. It is easy, therefore, to imagine how much
greater may have been the inundation, if this valley
was ever convulsed by a violent earthquake,*
Humboldt relates the interesting fact that after
the annihilation of a large part of the inhabitants of
Cumana, by an earthquake in 1766, a season of ex-
traordinary fertility ensued, in consequence of the
great rains which accompanied the subterranean con-
vulsions. ‘The Indians,” he says, “ celebrated, after
the ideas of an antique superstition, by festivals and

> See Davis on « The Chinese,” published by the Soc. for the
Diffus. of Use. Know. vol. i. p. 128.

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E2 EGYPTIAN COSMOGONY. [Book I.

dancing, the destruction of the world and the ap-
proaching epoch of its regeneration.” *

The existence of such rites among the rude nations
of South America is most important, for it shows what
effects may be produced by great catastrophes of this
nature, recurring at distant intervals of time, on the
minds of a barbarous and uncultivated race. The
superstitions of a savage tribe are transmitted through
all the Progressive stages of society, till they exert a
powerful influence on the mind of the philosopher.
He may find, in the monuments of former changes on
the earth’s surface, an apparent confirmation of tenets
handed down through successive generations, from the
rude hunter, whose terrified imagination drew a false
picture of those awful visitations of floods and earth-
quakes, whereby the whole earth as known to him was
simultaneously devastated.

Egyptian Cosmogony. Respecting the cosmogony |
of the Egyptian priests, we gather much information
from writers of the Grecian sects, who borrowed
almost all their tenets from Egypt, and amongst others
that of the former successive destruction and reno-
vation of the world.+ We learn from Plutarch, that
this was the theme of one of the hymns of Orpheus,
so celebrated in the fabulous ages of Greece. It was
brought by him from the banks of the Nile ; and we
even find-in his verses, as in the Indian systems, a
definite period assigned for the duration of each suc-
cessive world.t The returns of great catas

trophes
were determined by the period of the Annus

Magnus,
* Humboldt et Bonpland, Voy. Relat. Hist. vol, i. p. 30.
+ Prichard’s Egypt. Mythol. p. 177.
ł Plut, de Defectu Oraculorum, cap. 12. Censorinus de Die
Natali. See also Prichard’s Egypt. Mythol. P. 182,

Ch. IL] EGYPTIAN COSMOGONY. 13

or great year,—a cycle composed of the revolutions
of the sun, moon, and planets, and terminating when
these return together to the same sign whence they
were supposed at some remote epoch to have set out.
The duration of this great cycle was variously esti-
mated. According to Orpheus, it was 120,000 years;
according to others, 300,000; and by Cassander it was
taken to be 360,000 years.*

We learn particularly from the Timzeus of Plato,
that the Egyptians believed the world to be subject to
Occasional conflagrations and deluges, whereby the
gods arrested the career of human wickedness, and
purified the earth from guilt. After each regeneration,
mankind were in a state of virtue and happiness, from
which they gradually degenerated again into vice and
immorality. From this Egyptian doctrine, the poets
derived the fable of the decline from the golden to the
iron age. The sect of Stoics adopted most fully the
System of catastrophes destined at certain intervals to
destroy the world. These they taught were of two
kinds ;—the Cataclysm, or destruction by deluge,
which sweeps away the whole human race, and anni-
hilates all the animal and vegetable productions of
Nature; and the Ecpyrosis, or conflagration, which dis-
solves the globe itself. From the Egyptians also they
derived the doctrine of the gradual debasement of man
from a state of innocence. Towards the termination of
each era the gods could no longer bear with the wicked-
ness of men, and a shock of the elements or a deluge
overwhelmed them ; after which calamity, Astrea again
descended on the earth, to renew the golden age.+

The connection between the doctrine of successive

* Prichard’s Egypt. Mythol. p. 182. ` + Ibid. p. 193.

14 EGYPTIAN COSMOGONY. [Book I.

catastrophes and repeated deteriorations in the moral
character of the human race, is more intimate and na-
tural than might at first be imagined. For, in a rude
state of society, all great calamities are regarded by
the people as judgments of God on the wickedness of
man. Thus in our own time, the priests persuaded a
large part of the population of Chili, and perhaps be-
lieved themselves, that the fatal earthquake of 1822
was a sign of the wrath of Heaven for the great poli-
tical revolution just then consummated in South
America. In like manner, in the account given to
Solon by the Egyptian priests, of the submersion of the
island of Atlantis under the waters of the ocean, after
repeated shocks of an earthquake, we find that the
event happened when Jupiter had seen the moral de-
pravity of the inhabitants.* Now, when the notion
had once gained ground, whether from causes before
suggested or not, that the earth had been destroyed by
several general catastrophes, it would next be inferred
that the human race had been as often destroyed and
renovated. And since every extermination was as-
sumed to be penal, it could only be reconciled with
divine justice, by the supposition that man, at each
successive creation, was regenerated in astate of purity
and innocence.
A very large portion of Asia, inhabited by the ear-
liest nations whose traditions have come down to us,
has been always subject to tremendous earthquakes.
Of the geographical boundaries of these, and their
effects, I shall speak in the proper place. Egypt has,
for the most part, been exempt from this scourge, and

* Plato’s Timzus,

Ch. IL] EGYPTIAN COSMOGONY. 15

the tradition of catastrophes in that country was per-
haps derived from the East.
One extraordinary fiction of the Egyptian mythology
was the supposed intervention of a masculo-feminine
principle, to which was assigned the development of
the embryo world, somewhat in the way of incubation.
For the doctrine was, that when the first chaotic mass
“had been produced, in the form of an egg, by a self-
dependent and eternal Being, it required the mysterious
functions of this masculo-feminine artificer to reduce `
the component elements into organized forms.
Although it is scarcely possible to recall to mind
this conceit without smiling, it does not seem to differ
essentially in principle from some cosmological notions
of men of great genius and science in modern Europe.
The Egyptian philosophers ventured on the perilous
task of seeking from among the processes now going
on something analogous to the mode of operation em-
ployed by the Author of Nature in the first creation of
organized beings, and they compared it to that which
governs the birth of new individuals by generation.
To suppose that some general rules might be observed
in the first origin of created beings, or the first intro-
duction of new species into our system, was not absurd,
nor inconsistent with any thing known to us in the
economy of the universe. But the hypothesis, that
there was any analogy between such laws and those
employed in the continual reproduction of species, was
purely gratuitous. In like manner, it is not unreason-
able, nor derogatory to the attributes of Omnipotence,
to imagine that some general laws may be observed
in the creation of new worlds; and if man could
witness the birth of such worlds, he might reason by
induction upon the origin of his own. But in the ab-

EET IE ISNT OAT
iT

16 PYTHAGOREAN SYSTEM. [Book I;

sence of such data, an attempt has been made to fancy
some analogy between the agents now employed to
destroy, renovate, and perpetually vary the earth’s sur-
face, and those whereby the first chaotic mass was
formed, and brought by supposed nascent energy from
the embryo to the habitable state.

By how many shades the elaborate Systems, con-
structed on these principles, may differ from the mys--
teries of the “Mundane Egg” of Egyptian fable, I
shall not inquire. It would, perhaps, be dangerous
ground ; and some of our contemporaries might not sit
as patiently as the Athenian audience, when the fiction
of the chaotic egg, engrafted by Orpheus upon their
own mythology, was turned into ridicule by Aristo-
phanes. That comedian introduced his birds singing,
in a solemn hymn, « How sable-plumaged Night con-
ceived in the boundless bosom of Erebus, and laid an
egg, from which, in the revolution of ages, sprung
Love, resplendent with golden pinions. Love fecun-
dated the dark-winged chaos, and gave origin to the
race of birds.” *

Pythagorean Doctrines. — Pythagoras, ‘who resided
for more than twenty years in Egypt, and, according
to Cicero, had visited the East, and conversed with
the Persian philosophers, introduced into his own
country, on his return, the doctrine of the gradual de-
terioration of the human race from an original state
of virtue and happiness: but if we are to judge of his
theory concerning the destruction and renovation of
the earth from the sketch given by Ovid, we must
concede it to have been far more philosophical than
any known ‘version of the cosmologies of Oriental or

Egyptian sects. |
* Aristophanes, Birds, 694,

Ch, IL] ` PYTHAGOREAN SYSTEM. iz

Although Pythagoras is introduced by the poet as
delivering his doctrine in person, some of the illustra-
tions are derived from natural events which happened
after the death of the philosopher. But nothwithstand-
ing these anachronisms, we may regard the account as
a true picture of the tenets of the Pythagorean school
in the Augustan age; and although perhaps partially
modified, it must have contained the substance of the
original scheme. Thus considered, it is extremely
curious and instructive; for we here find a compre-
hensive and masterly summary of almost all the great
causes of change now in activity on the globe, and
these adduced in confirmation of a principle of per-
petual and gradual revolution inherent in the nature of
our terrestrial system. These doctrines, it is true, are
not directly applied to the.explanation of geological
phenomena ; or, in other words, no attempt is made to
estimate what may have been in past ages, or what
may hereafter be, the aggregate amount of change
brought about by such never-ending fluctuations. Had
this been the case, we might have been called upon to
admire so extraordinary an anticipation with no less
interest than astronomers, when they endeavour to
divine by what means the Samian philosopher came to
the knowledge of the Copernican system.

Let us now examine the celebrated passages to
which we have been adverting * : —

“ Nothing perishes in this world; but things merely
vary and change their form. To be born, means simply
that a thing begins to be something different from what
it was before; and dying, is ceasing to be the same
thing. Yet, although nothing retains long the same

* Ovid’s Metamor. lib. 15,

-18 PYTHAGOREAN SYSTEM. [Book I,

image, the sum of the whole remains constant.” These
general propositions are then confirmed by a series of
examples, all derived from natura] appearances, except
the first, which refers to the golden age giving place
to the age of iron. The illustrations are thus conse-
cutively adduced.

1. Solid land has been converted into sea.

2. Sea has been changed into land. Marine shells
lie far distant from the deep, and the anchor has been
found on the summit of hills.

3. Valleys have been excavated by running water,
and floods have washed down hills into the sea. *

4. Marshes have become dry ground.

5. Dry lands have been changed into stagnant pools,

6. During earthquakes some springs have been
closed up, and new ones have broken out. Rivers
have deserted their channels, and have been re-born
elsewhere ; as the Erasinus in Greece, and Mysus in
Asia.

7. The waters of some rivers, formerly sweet, have
become bitter, as those of the Anigris in Greece, &e.F

8. Islands have become connected with the main
Jand, by the growth of deltas and new deposits, as in the
case of Antissa joined to Lesbos, Pharos to Egypt, &c.

9. Peninsulas have been divided from the main land,
and have become islands, as Leucadia; and according
to tradition Sicily, the sea having carried away the
isthmus,

* Eluvie mons est deductus in æquor, v. 267. The meaning
of this last verse is somewhat obscure, but, taken with the context,
may be supposed to allude to the abrading power of floods, tor-
rents, and rivers.

+ The impregnation from new mineral Springs, caused by
earthquakes in volcanic countries, is, perhaps, here alluded to.

Ch. IT] PYTHAGOREAN SYSTEM. 19

10. Land has been submerged by earthquakes: the
Grecian cities of Helice and Buris, for example, are to
be seen under the sea, with their walls inclined.

11. Plains have been upheaved into hills by the
confined air seeking vent, as at sing cele in the Pelo-
ponnesus.

12. The temperature of some springs varies at
different periods. The waters of others are inflam-
mable. *

13. There are streams which have a petrifying
power, and convert the substances which they touch
into marble.

14. Extraordinary medicinal and deleterious effects
are produced by the water of different lakes and
springs. F

15. Some rocks and islands, after floating and having
been subject to violent movements, have at length
become stationary and immoveable, as Delos, and the
Cyanean Isles. $

16. Volcanic vents shift their position ; there was a
time when Etna was not a burning mountain, and the

* This is probably an allusion to the escape of inflammable gas,
like that in the district of Baku, west of the Caspian; at Pietra-
mala, in the Tuscan Apennines; and several other places. '

+ Many of those described seem fanciful fictions, like the
virtues still so commonly attributed to mineral waters.

f Raspe, in a learned and. judicious essay (De Novis Insulis,
cap. 19.), has made it appear extremely probable that all the
traditions of certain islands in the Mediterranean having at some
former time frequently shifted their positions, and at length become
- stationary, originated in the great change produced in their form
by earthquakes and submarine eruptions, of which there have
been modern examples in the new islands raised in the time of

history. When the series of convulsions ended, the island was
' said to become fixed.

90 ARISTOTELIAN SYSTEM. [Book I.

time will come when it will cease to burn. Whether
it be that some caverns become closed up by the move-
ments of the earth, and others opened, or whether the
fuel is finally exhausted, &c. &c. i

The various causes of change in the inanimate
world having been thus enumerated, the doctrine of
equivocal generation is next propounded, as illus-
trating a corresponding perpetual flux in the animate
creation.*

In the Egyptian and Eastern cosmogonies, and in
the Greek version of them, no very definite meaning
can, in general, be attached to the term “ destruction
of the world ;” for sometimes it would seem almost to
imply the annihilation of our planetary system, and at
others a mere revolution of the surface of the earth.

Opinions of Aristotle. —From the works now extant
of Aristotle, and from the system of Pythagoras, as
above exposed, we might certainly infer that these
philosophers: considered the agents of change now
Operating in nature, as capable of bringing about in

* It is not inconsistent with the Hindoo mythology to suppose
that Pythagoras might have found in the East not only the system
of universal and violent catastrophes and periods of repose in end-
less succession, but also that of periodical revolutions, effected by
the continued agency of ordinary causes. For Brahma, Vishnu,
and Siva, the first, second, and third persons of the Hindoo triad,

severally represented the Creative, the Preserving, and the De-
stroying powers of the Deity. The co-existence of these three
attributes, all in simultaneous operation, might well accord with
the notion of perpetual but partial alterations finally bringing
about a complete change. But the fiction expressed in the verses
before quoted from Mend, of eternal vicissitudes in the vigils and
slumbers of the Infinite Being, seems accommodated to the sys-
tem of great general catastrophes followed by new creations and

periods of repose.

Ch. I1] ARISTOTELIAN SYSTEM. 21

the lapse of ages. a complete revolution; and the
Stagyrite even considers occasional catastrophes, hap-
pening at distant intervals of time, as part of the
regular and ordinary course of nature. The deluge
of Deucalion, he says, affected Greece only, and prin-
Cipally the part called Hellas, and it arose from great
inundations of rivers during a rainy winter. But such
extraordinary winters, he says, though after a certain
period they return, do not always revisit the same
places.*

Censorinus quotes it as Aristotle’s opinion, that
there were general inundations of the globe, and that
they alternated with conflagrations; and that the flood
constituted the winter of the great year, or astro-
nomical cycle, while’the conflagration, or destruction
by fire, is the summer or period of greatest heat.+
If this passage, as Lipsius supposes, be an amplifi-
cation, by Censorinus, of what is written in “the
Meteorics,” it is a gross misrepresentation of the
doctrine of the Stagyrite, for the general bearing of
his reasoning in that treatise tends clearly in an oppo-
Site direction. He refers to many examples of; changes
„now constantly going on, and insists emphatically on.
the great results which they must produce in the
lapse of ages.. He instances particular cases of lakes
that had dried up, and deserts that had at length
become watered by rivers and fertilized. He points
to the growth of the Nilotic delta since the time of
Homer, to the shallowing of the Palus Mzotis within
sixty years from his own time; and although, in the
same chapter, he says nothing of earthquakes, yet in
others of the same treatise he shows himself not

* Meteor. lib, i. cap. 12. + De Die Nat.

99 ARISTOTELIAN SYSTEM, [Book 1,

unacquainted with their effects.* He alludes, for
example, to the upheaving of one of the Eolian islands
previous to a volcanic eruption. « The changes of the
earth,” he says, “ are so slow in comparison to the du-
ration of our lives, that they are overlooked (Aavbaver);
and the migrations of people after great catastrophes,
and their removal to other regions, cause the event to
be forgotten.” +

When we consider the acquaintance displayed by
Aristotle, in his various works, with the destroying
and renovating powers of Nature, the introductory
and concluding passages of the twelfth chapter of his
“ Meteorics” are certainly very remarkable. In the
first sentence he says, “The distribution of land and
sea in particular regions does not endure throughout
all time, but it becomes sea in those parts where it was
land, and again it becomes land where it was sea; and
there is reason for thinking that these changes take
place according to a certain system, and within a certain
period.” The concluding observation is as follows:
_— “As time never fails, and the universe is eternal,
neither the Tanais, nor the Nile, can have flowed for
ever. The places where they rise were once dry,
and there is a limit to their operations ; but there is
none to time. So also of all other rivers; they spring
up, and they perish; and the sea also continually
déserts some lands and invades others. The same
tracts, therefore, of the earth are not, some always
sea, and others always continents, but every thing
changes in the course of time.”

It seems, then, that the Greeks had not only derived
from preceding nations, but had also, in some slight

* Lib. il. cap. IEG 15 and 16. + Ibid. ;

Ch. IL] CREATION OF SPECIES, 23

degree, deduced from their own observations, the
theory of periodical revolutions in the inorganic world:
there is, however, no ground for imagining that
they contemplated former changes in the races of
animals and plants. Even the fact that marine re-
mains were inclosed in solid tocks, although observed
by Some, and even made the groundwork of geological
Speculation, never stimulated the industry or guided
the inquiries of naturalists. It is not impossible that
the theory of equivocal generation might have en-
gendered some indifference on this subject, and that a
belief in the spontaneous production of living beings
from the earth or corrupt matter might have caused
the crganic world to appear so unstable and fluctuating,
that phenomena indicative of former changes would
not awaken intense curiosity. The Egyptians, it is true,
had taught, and the Stoics had repeated, that the
earth had once given birth to some monstrous animals,
Which existed no longer ;,but the prevailing opinion
Seems to have been, that after each great catastrophe
the same species of animals were created over again,
This tenet is implied in a passage of Seneca, where,
Speaking of a future deluge, he says, “ Every animal
Shall be generated anew, and man free from guilt shall
be given to the earth.” *

An old Arabian version of the doctrine of the suc-
cessive revolutions of the globe, translated by Abraham
Ecchellensis t, seems to form a singular exception to

* ; t À ; ,
Omne ex integro animal generabitur, dabiturque terris homo

inscius scelerum, — Quest. Nat. iii. c. 29.

t This author was Regius Professor of Syriac and Arabic at
Paris, where, in 1685, he published a Latin translation of many
Arabian MSS. on different departments of philosophy. This
work has always been considered of high authority.

94, THEORY OF STRABO. [Book I.

the general rule, for here we find the idea of different
genera and species having been created. The Ger-
banites, a sect of astronomers who flourished some
centuries before the Christian era, taught as follows :
—“ That after every period of thirty-six thousand four
hundred and twenty-five years, there were produced a
pair of every species of animal, both male and female,
from whom animals might be propagated and inhabit
this lower world. But when a circulation of the
heavenly orbs was completed, which is finished in that
space of years, other genera and species of animals are
propagated, as also of plants and other things, and the
first order is destroyed, and so it goes on for ever and
ever.” *

Theory of Strabo. — As we learn much of the tenets
of the Egyptian and oriental schools in the writings of
the Greeks, so many speculations of the early Giek

* Gerbanitæ docebant singulos triginta sex mille annos qua-
dringentos, viginti quinque bina ex singulis animalium speciebus
produci, marem scilicet ac feminam, ex quibus animalia propa-
gantur, huncque inferiorem incolunt orbem. Absoluta autem
celestium orbium circulatione, que illo annorum conficitur spatio,

iterum alia producuntur animalium genera et species, quemad-

modum et plantarum aliarumque rerum, et primus destruitur ordo,
sicque in infinitum producitur. — Histor. Orient. Suppl. per
Abrahamum Ecchellensum, Syrum Maronitam, cap. 7. et 8.
calcem Chronici Oriental. Parisiis, e Typ. regia, 1685, fol.

I have given the punctuation as in the Paris edition, there
being no comma after quinque; but, at the suggestion of M. de
Schlegel, I have referred the number twenty-five to the period of
years, and not to the number of pairs of each species created at

one time, as I had done in the two first editions. Fortis inferred

that twenty-five new species only were created at a time; a con-
struction which the passage will not admit. Mém. sur l’Hist.
Nat. de l'Italie, vol. i. p. 202.

Ch. IL] THEORY OF STRABO. 25

authors are made known to us in the works of the
Augustan and later ages. Strabo, in particular, enters
largely, in the second book of his Geography, into the
opinions of Eratosthenes and other Greeks on one of the
most difficult problems in geology, viz. by what causes
Marine shells came to be plentifully buried in the earth
at such great elevations and distances from the sea.
He notices, amongst others, the explanation of
Xanthus the Lydian, who said that the seas had once
been more extensive, and that they had afterwards
been partially dried up, as in his own time many lakes,
rivers, and wells in Asia had failed during a season of
drought. Treating this conjecture with merited dis-
regard, Strabo passes on to the hypothesis of Strato, the
natural philosopher, who had observed that the quantity
of mud brought down by rivers into the Euxine was so
great, that its bed must be gradually raised, while the
rivers still continue to pour in an undiminished quantity
of water. He, therefore, conceived that, originally,
when the Euxine was an inland sea, its level had by
this means become so much elevated that it burst its
barrier near Byzantium, and formed a communication
With the Propontis; and this partial drainage, he sup-
posed, had already converted the left side into marshy
ground, and thus, at last, the whole would be choked
Up with soil. So, it was argued, the Mediterranean had
once opened a passage for itself by the Columns of
Hercules into the Atlantic; and perhaps the abund-
ance of sea-shells in Africa, near the Temple of Jupiter
Ammon, might also be the deposit of some former

inland Sea, which had at length forced a passage and
escaped,

But Strabo rejects this theory, as insufficient to ac-

count for all the phenomena, and he proposes one of
VOL. I. c

26 THEORY OF STRABO. [Book I.

his own, the profoundness of which modern geologists
are only beginning to appreciate. « Itis not,” he says,
“ because the lands covered by seas were originally at
different altitudes, that the waters have risen, or sub-
sided, or receded from some parts and inundated
others. But the reason is, that the same land is some-
times raised up and sometimes depressed, and the sea
also is simultaneously raised and depressed, so that it
either overflows or returns into its own place again.’
We must, therefore, ascribe the cause to the ground,
either to that ground which is under the sea, or to
that which becomes flooded by it, but rather to that
which lies beneath the sea, for this is more moveable,
and, on account of its humidity, can be altered with
greater celerity.* Jt is proper,” he observes in
continuation, “to derive our explanations from things
which are obvious, and in some measure of daily occur-
rence, such as deluges, earthquakes, and voleanie erup-
tions +, and sudden swellings of the land beneath the sea;
for the last raise up the sea also; and when the same
lands subside again, they occasion the sea to be let
down. And it.is not merely the small, but the large

* “ Quod enim hoe attollitur aut subsidit, et vel inundat

quædam loca, vel ab iis recedit, ejus rei causa non est, quod alia
aliis sola humiliora sint aut altiora; sed quod idem solum modd
attollitur modd deprimitur, simulque etiam mod6 attollitur modo
deprimitur mare: itaque vel exundat vel in suum redit locum.”
Posted, p. 88. “ Restat, ut causam adscribamus solo, sive
quod mari subest sive quod inundatur ; potiùs tamen ei quod

mari subest. Hoc enim multò est mobilius, et quod ob humidita-
tem celeriùs mutari possit.” — Strabo, Geog. Edit. Almelov.
Amst. 1707. lib. i.

+ Volcanic eruptions, eruptiones flatuum, in the Latin transla-
tion, and in the original Greek, avaguonuara, gaseous eruptions ?
or inflations of land ?— ibid., p. 93.

Ch, IL] KNOWLEDGE OF THE ANCIENTS, 27

islands also, and not merely the islands, but the con-
tinents, which can be lifted up together with the sea;
and both large and small tracts may subside, for habi-
tations and cities, like Bure, Bizona, and many others,
have been engulphed by earthquakes.”

In another place, this learned geographer, in allud-
ing to the tradition that Sicily had been separated by
a convulsion from Italy, remarks, that at present the
land near the sea in those parts was rarely shaken
by earthquakes, since there were now open orifices
whereby fire and ignited matters, and waters escape ;
but formerly, when the volcanos of Etna, the Lipari
Islands, Ischia, and others, were closed up, the impri-
soned fire and wind might have produced far more
vehement movements.* The doctrine, therefore, that
volcanos are safety valves, and that the subterranean
convulsions are probably most violent when first the
volcanic energy shifts itself to a new quarter, is not
modern.

We learn from a passage in Strabo't, that it was a
dogma of the Gaulish Druids that the universe was
immortal, but destined to survive catastrophes both of
fire and water. That this doctrine was communicated
to them from the East, with much of their learning,
cannot be doubted. Cæsar, it will be remembered,
Says that they made use of Greek letters in arithme-
tical computations. f

Pliny.—This philosopher had no theoretical opinions
of his own concerning changes of the earth’s surface ;
and in this department, as in others, he restricted him-
self to the task of a compiler, without reasoning on the
facts stated by him, or attempting to digest them into

* Strabo, lib. vi. P. 396. + Book iv.
ł L. vi. ch. xiii,

(e

i

SEE So `- =

2 SS
oT
y

28 KNOWLEDGE OF THE ANCIENTS. [Book I.

`

regular order. But his enumeration of the new islands
which had been formed in the Mediterranean, and of
other convulsions, shews that the ancients had not
been inattentive observers of the changes which had
taken place within the memory of man.

Such, then, appear to have been the opinions enter-
tained before the Christian era, concerning the past
revolutions of our globe. Although no particular in-
vestigations had been made for the express purpose of
interpreting the monuments of ancient changes, they
were too obvious to be entirely disregarded; and the
observation of the present course of nature presented
too many proofs of alterations continually in progress
on the earth to allow philosophers to believe that na-
ture was in a state of rest, or that the surface had
remained, and would continue to remain, unaltered.
But they had never compared. attentively the results
of the destroying and reproductive operations of mo-
dern times with those of remote eras, nor had they
ever entertained so much as a conjecture concerning
the comparative antiquity of the human race, or of
living species of animals and plants, with those belong-
ing to former conditions of the organic world. They
had studied the movements and positions of the hea-
venly bodies with laborious industry, and made some
progress in investigating the animal, vegetable, and
mineral kingdoms; but the ancient history of the globe
was to them a sealed book, and, although written in
characters of the most striking and imposing kind, they
were unconscious even of its existence.

CHAPTER III.
HISTORY OF THE PROGRESS OF GEOLOGY — continued.

Arabian writers of the tenth century — Avicenna — Omar —
Cosmogony of the Koran — Kazwini— Early Italian writers
(p. 34, )— Fracastoro — Controversy as to the real nature of
fossils — Attributed to the Mosaic deluge — Palissy — Steno

| (p. 40.) — Scilla — Quirini — Boyle — Lister — Leibnitz —
Hooke’s Theory of Elevation by Earthquakes (p. 47.) — Of

-lost species of animals — Ray — Physico-theological writers
— Woodward’s Diluvial Theory (p. 54.) — Burnet— Whiston

. — Vallisneri — Lazzaro Moro (p. 60.) — Generelli — Buffon
(p; 68.) — His theory condemned by the Sorbonne as unortho-
dox— His declaration — Targioni — Arduino — Michell —
Catcott — Raspe — Fuchsel (p. 76.) — Fortis — Testa —
Whitehurst — Pallas — Saussure.

Arabian writers.— AFTER the decline of the Roman
empire, the cultivation of physical science was first
revived with some success by the Saracens, about the
middle of the eighth century of our era. The works
of the most eminent classic writers were purchased at
great expense from the Christians, and translated into
Arabic; and Al Mamin, son of the famous Harûn-al-
Rashid, the contemporary of Charlemagne, received
with marks of distinction, at his court at Bagdad,
astronomers and men of learning from different coun-
tries. This caliph, and some of his successors, en-
countered much opposition and jealousy from the
doctors of the Mahomedan law, who wished the Mos-
lems to confine their studies to the Koran, dreading

the effects of the diffusion of a taste for the physical
sciences, *

* Mod. Univ. Hist. vol. ii. chap. iv. sectioniii.

c 3

\

30 AVICENNA — OMAR — THE KORAN. [Book I,

Avicenna. — Almost `all the works of the early
Arabian writers are lost. Amongst those of the tenth
century, of which fragments are now extant, is a short
treatise “ On the Formation and Classification of Mine-
rals,” by Avicenna, a physician, in whose arrangement
there is considerable merit. The second chapter,
“On the Cause of Mountains,” is remarkable; for
mountains, he says, are formed, some by essential,
others by accidental causes. In illustration of the
essential, he instances “a violent earthquake, by which
land is elevated, and becomes a mountain ;” of the ac-
cidental, the principal, he says, is excavation by water,
whereby cavities are produced, and adjoining lands
made to stand out and form eminences.*

Omar — Cosmogony of the Koran.—In the same
century also, Omar, surnamed “ El Aalem,” or “ The
Learned,” wrote a work on “ The Retreat of the Sea.”
It appears that on comparing the charts of his own
time with those made by the Indian and Persian astro-
nomers two thousand years before, he had satisfied
himself that important changes had taken place since
the times of history in the form of the coasts of Asia,
and that the extension of the sea had been greater at
some former periods. He was confirmed in this opi-
nion by the numerous salt springs and marshes in the
interior of Asia,— a phenomenon from which Pallas, in
more recent times, has drawn the same inference,

Von Hoff has suggested, with great probability, that
the changes in the level of the Caspian (some of which
there is reason to believe have happened within the

* Montes quandoque fiunt ex causa essentiali, quandéque ex
causa accidentali. Ex essentiali causa, ut ex vehementi motu
terre elevatur terra, et fit mons. Accidentali, &c. — De Con-
gelatione Lapidum, ed. Gedani, 1682.

Ch, 111] OMAR — THE KORAN. 31

historical era), and the geological appearances in that
district, indicating the desertion by that sea of its an-
cient bed, had probably led Omar to his theory of a
general' subsidence. But whatever may have been the
proofs relied on, his system was declared contradictory
to certain passages in the Koran, and he was called
Upon publicly to recant his errors; to avoid which
persecution he went into voluntary banishment from
Samarkand.*

The cosmological opinions expressed in the Koran
are few, and merely introduced incidentally: so that
it is not easy to understand how they could have in-
terfered so seriously with free discussion on the former
changes of the globe. The Prophet declares that the
earth was created in two days, and the mountains were
then placed on it; and during these, and two addi-
tional days, the inhabitants of the earth were formed ;
and in two more the seven heavens.+ There is no

* Von Hoff, Geschichte der Veränderungen der Erdoberfläche,
vol. i. p. 406., who cites Delisle, bey Hismann Welt-und Völker-
geschichte. Alte Gesch. .1"°" Theil. s. 234. — The Arabian
persecutions for heretical dogmas in theology were often very
sanguinary. In the same ages wherein learning was most in
esteem, the Mahometans were divided into two sects, one of whom
Maintained that the Koran was increate, and had subsisted in the
very essence of God from all eternity ; and the other, the Motaza-
lites, who, admitting that the Koran was instituted by God, con-
ceived it to have been first made when revealed to the Prophet at

Mecca, and accused their opponents of believing in two eternal
beings,

The opinions of each of these sects were taken up by
different caliphs in succession, and the followers of each some-
times submitted to be beheaded, or flogged till at the point of

death, rather than renounce their creed. — Mod. Univ. Hist.
vol. ii. ch. iv.

t Koran, chap. xli.
c4

39 OMAR — THE KORAN. | [Book I.

more detail of circumstances; and the deluge, which
is also mentioned, is discussed with equal brevity.
The waters are represented to have poured out of an
oven; a strange fable, said to be borrowed from the
Persian Magi, who represented them as issuing from
the oven of an old woman.* All men were drowned,
save Noah and his family ; and then God said, “O earth,
swallow up thy waters; and thou, O heaven, withhold
thy rain ;” and immediately the waters abated.+

We may suppose Omar to have represented the
desertion of the land by the sea to have been gradual,
and that his hypothesis required a greater lapse of
ages than was consistent with Moslem orthodoxy ; for
‘ it is to be inferred from the Koran, that man and this
planet were created at the same time; and although
Mahomet did not limit expressly the antiquity of the
human race, yet he gave an implied sanction to the
Mosaic chronology, by the veneration expressed by
him for the Hebrew Patriarchs. +

A manuscript work, entitled the “ Wonders of
Nature,” is preserved in the Royal Library at Paris,
by an Arabian writer, Mohammed Kazwini, who flou-
rished in the seventh century of the Hegira, or at the
close of the thirteenth century of our era.§ Besides
several curious remarks on aerolites, earthquakes, and
the successive changes of position which the land and

* Sales Koran, chap. xi. see note, + Ibid.

ł Kossa, appointed master to the Caliph Al Mamûd, was au-
thor of a book, entitled «* The History of the Patriarchs and Pro-
phets, from the Creation of the World.” — Mod. Univ. Hist. vol. ii.
chap. iv.

§ Translated by MM. Chezy and De Sacy, and cited by
M. Elie de Beaumont, Ann. des Sci. Nat. 1832.

0) MOHAMMED KAZWINI. 33

: sea have undergone, we meet with the following
beautiful passage, which is given as the narrative of
Khidhz, an allegorical personage: — “ I passed one day
by a very ancient and wonderfully populous city, and
asked one of its inhabitants how long it had been
‘founded. <Itis indeed a mighty city,’ replied he, ‘we
know not how long it has existed, and our ancestors
Were on this subject as ignorant as ourselves.’ Five
centuries afterwards, as I passed by the same place, I
could not perceive the slightest vestige of the city. I
demanded of a peasant who was gathering herbs, upon
its former site, how long it had been destroyed. ‘In
sooth, a strange question !’ replied he. ‘ The ground
here has never been different from what you now behold
it’ —‘ Was there not of old,’ said I, ‘a splendid city
here ?’— < Never,’ answered he, ‘so far as we have
seen, and never did our fathers speak to us of any such.’
On my return there, 500 years afterwards, I found the
sea in the same place, and on its shores were a party of
fishermen, of whom I inquired how long the land had
been covered by the waters? ‘Is this a question,’ said
they, ‘for a man like you? this spot has always been
what it is now. ` I again returned, 500 years after-
wards, and the sea had disappeared ; I inquired of a
man who stood alone upon the spot, how long ago this
change had taken place, and he gave me the same
answer as I had received before. Lastly, on coming
back again after an equal lapse of time, I found there
a flourishing city, more populous and more rich in
beautiful buildings than the city I had seen the first
time, and when I would fain have informed myself
concerning its origin, the inhabitants answered me,
‘Its rise is lost. in remote antiquity: we are ignorant

re

co

a STS?

3A, = FRACASTORO. [Book 1,

how long it has existed, and our fathers were on this
subject as ignorant as ourselves.’ ”

Early Italian writers — Fracastoro, 151'7.— It was
not till the earlier part of the sixteenth century that
geological phenomena began to attract the attention
of the Christian nations. At that period a very
animated controversy sprang up in Italy, concerning
the true nature and origin of marine shells, and other
organized fossils, found abundantly in the strata of the
peninsula.* The excavations made in 1517, for re-
pairing the city of Verona, brought to light a multitude
of curious petrifactions, and furnished matter for
speculation to different authors, and among the rest
to Fracastoro +, who declared his opinion, that fossil
shells had all belonged to living animals, which had
formerly lived and multiplied where their exuviæ are
now found. He exposed the absurdity of having
recourse to a certain “ plastic force,” which it way said
had power to fashion stones into organic forms; and,
with no less cogent arguments, demonstrated the
futility of attributing the situation of the shells in
question to the Mosaic deluge, a theory obstinately
defended by some. That inundation, he observed,
was too transient, it consisted principally of fluviatile
waters; and if it had transported shells to great dis-
tances, must have strewed them over the surface, not
buried them at vast depths in the interior of mountains.
His clear exposition of the evidence would have ter-
minated the discussion for ever, if the passions of -
mankind had not been enlisted in the dispute; and

* See Brocchi’s Discourse on the Progress of the Study of
Fossil Conchology in Italy, where some of the following notices
on Italian writers will be found more at large,

+ Museum Calceol.

Ch, 1L] _ ' EARLY ITALIAN WRITERS. 35

even though doubts should for a time have remained
in some minds, they would speedily have been removed
_ by the fresh information obtained almost immediately
afterwards, respecting the structure of fossil remains,
and of their living analogues.

But the clear and philosophical views of Fracastoro
were disregarded, and the talent and argumentative
Powers of the learned were doomed for three centuries
to be wasted in the discussion of these two simple and -
preliminary questions : first, whether fossil remains had
ever belonged to living creatures; and, secondly,
whether, if this be admitted, all the phenomena could
not be explained by the Noachian deluge. It had been
the general belief of the Christian world down to
the period now under consideration, that the origin
of this planet was not more remote than a few thou-
Sand years ; and that since the creation the deluge was
the only great catastrophe by which considerable
Change had been wrought on the earth’s surface. On
the other hand, the opinion was scarcely less general,
that the final dissolution of our system was an event to
be looked for at no distant period. The era, it is true,
of the expected millennium had passed away ; and for
five hundred years after the fatal hour, when the
annihilation of the planet had been looked for, the
monks remained in undisturbed enjoyment of rich
stants of land bequeathed to them by pious donors,
Who, in the preamble of deeds beginning “ appropin-
quante mundi termino ” “ appropinquante magno

judicii die,” left lasting monuments of the popular
delusion.*

* In Sicily, in particular, the title-deeds of many valuable
grants of land to the monasteries are headed by such preambles,

c 6

ae Sa.

a a

TS ae ae

36 ANTIQUITY OF THE EARTH, - [Book f.

But although in the sixteenth century it had become
necessary to interpret the prophecies more liberally,
and to assign a more distant date to the future con-
flagration of the world, we find, in the speculations of
the early geologists, perpetual allusion to such an ap-
proaching catastrophe ; while in all that regarded the
antiquity of the earth, no modification whatever of the
opinions of the dark ages had been effected. Consider-
able alarm was at first excited when the attempt was
made to invalidate, by physical proofs, an article of
faith so generally received; but there was sufficient
spirit of toleration and candour amongst the Italian
ecclesiastics, to allow the subject to be canvassed with
much freedom. They even entered warmly into the
controversy themselves, often favouring different sides
of the question; and however much we may deplore
the loss of time and labour devoted to the defence of
untenable positions, it must be conceded, that they
displayed far less polemic bitterness than certain
writers who followed them “beyond the Alps,” two
centuries and a half later.

CONTROVERSY AS TO THE REAL NATURE OF FOSSIL
ORGANIC REMAINS,

Mattioli — Falloppio. — The system of scholastic
disputations encouraged in the universities of the
middle ages had unfortunately trained men to habits
of indefinite argumentation ; and they often preferred
absurd and extravagant propositions, because greater
skill was required to maintain them: the end and

composed by the testators about the period when the good King
Roger was expelling the Saracens from that island.

Ch. 1L] EARLY ITALIAN WRITERS. Ot

object of these intellectual combats being victory, and
not truth. No theory could be so far-fetched or fan-
tastical as not to attract some followers, provided it fell
in with popular notions; and as cosmogonists were
not at all restricted, in building their systems, to the
agency of known causes, the opponents of Fracastoro
met his arguments by feighing imaginary causes, which
differed from each other rather in name than in sub-
Stance. Andrea Mattioli, for instance, an eminent
botanist, the illustrator of Dioscorides, embraced the
notion of Agricola, a skilful German miner, that a cer-
tain “materia pinguis,’ or “ fatty matter,” set into
fermentation by heat, gave birth to fossil organic shapes.
Yet Mattioli had come to the conclusion, from his own
observations, that porous bodies, such as bones and
Shells, might be converted into stone, as being per-
Meable to what he termed the “ lapidifying juice.”
In like manner, Falloppio of Padua conceived that
petrified shells were generated by fermentation in the
Spots where they are found, or that they had in some
Cases acquired their form from “ the tumultuous move-
ments of terrestrial exhalations.” Although celebrated
as a professor of anatomy, he taught that certain tusks
of elephants dug up in his time at Puglia were mere
earthy concretions; and, consistently with these prin-
ciples, he even went so far as to consider it probable, -
that the vases of Monte Testaceo at Rome were
natural impressions stamped in the soil.* In the same
spirit, Mercati, who published, in 1574, faithful figures
of the fossil shells preserved by Pope Sixtus V. in the
Museum of the Vatican, expressed an opinion that
they were mere stones, which had assumed their

* De Fossilib. pp. 109. and 176.

TE Eu

38 NATURE OF ORGANIZED FOSSILS. [Book I,

peculiar configuration from the influence of the hea-
venly bodies ; and Olivi of Cremona, who described
the fossil remains of a rich Museum at Verona, was
satisfied with considering them as mere “ sports of
nature.”

Some of the fanciful notions of those times were
deemed less unreasonable, as being somewhat in har-
mony with the Aristotelian theory of spontaneous
generation, then taught in all the schools. For men
who had been taught in early youth, that a large pro-
portion of living animals and plants were formed from
the fortuitous concourse of atoms, or had sprung from
the corruption of organic matter, might easily per-
suade themselves, that organic shapes, often imper-
fectly preserved in the interior of solid rocks, owed
their existence to causes equally obscure and mys-
terious.

Cardano, 1552:— But there were not wanting some
who, during the progress of this century, expressed
more sound and sober opinions. The title of a work
of Cardano’s, published in 1552, “De Subtilitate”
(corresponding to what would now be called Trans-
cendental Philosophy), would lead us to expect, in the
chapter on minerals, many far-fetched theories cha-
racteristic of that age; but, when treating of petrified
shells, he decided that they clearly indicated the
former sojourn of the sea upon the mountains.*

Cesalpino — Majoli, 1597.— Cesalpino, a celebrated
botanist, conceived that fossil shells had been left on
the land by the retiring sea, and had concreted into
stone during the consolidation of the soil} ; and in the
following year (1597), Simeone Majoli} went still

# Brocchi, Con. Foss, Subap. Disc. sui Progressi. vol. i. p.57.

+ De Metallicis. -$ Dies Caniculares.

Ch, UL] _ PALISSY*~ COLONNA. 39

farther ; and, coinciding for the most part with the
views of Cesalpino, suggested that the shells and sub-
Marine matter of the Veronese, and other districts,
might have been cast up upon the land by volcanic
explosions, like those which gave rise, in 1538, to
onte Nuovo, near Puzzuoli. This hint seems to
have been the first imperfect attempt to connect the
Position of fossil shells with the agency of volcanos,
a System afterwards more fully developed by Hooke,
azzaro Moro, Hutton, and other writers.

Two years afterwards, Imperati advocated the ani-
mal origin of fossilized shells, yet admitted that stones
Could vegetate by force of “an internal principle ;”
and, as evidence of this, he referred to the teeth of

sh, and spines of echini found petrified.*

Palissy, 1580. — Palissy, a French writer on “ The

tigin of Springs from Rain-water,” and of other
SCientific works, undertook, in 1580, to combat the
notions of many of his contemporaries in Italy, that
Petrified shells had all been deposited by the universal
deluge, «He was the first,” said Fontenelle, when,
in the French Academy, he pronounced his eulogy,
Nearly a century and a half later, “ who dared assert,”
m Paris, that fossil remains of testacea and fish had
nce belonged to marine animals.

Lano Colonna. To enumerates the multitude of
talian Writers, who advanced various hypotheses, all
equally fantastical, in the early part of the seventeenth
century, would be unprofitably tedious; but Fabio
Colonna deserves to be distinguished ; for, although
he gave way to the dogma, that all fossil remains were
to be referred to the Noachian deluge, he resisted the
absurd theory of Stelluti, who taught that fossil wood

* Storia Naturale.

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SSS

40 STENO. [Book I.

and ammonites were mere clay, altered into such forms
by sulpbureous waters and subterranean heat; and he
pointed out the different states of shells buried in the
strata, distinguishing between, first, the mere mould or
impression ; secondly, the cast or nucleus ; and, thirdly,
the remains of the shell itself. He had also the merit
of being the first to point out, that some of the fossils
had belonged to marine, and some to terrestrial, tes-
tacea.*

Steno, 1669. — But the most remarkable work of
that period was published by Steno, a Dane, once
professor of anatomy at Padua, and who afterwards
resided many years at the court of the Grand Duke of
Tuscany. His treatise bears the quaint title of “ De
Solido intra Solidum naturaliter contento (1669),” by
which the author intended to express, “On Gems,
Crystals, and organic petrifactions inclosed within solid
Rocks.” This work attests the priority of the Italian
school in geological research; exemplifying at the
same time the powerful obstacles opposed, in that age,
to the general reception of enlarged views in the
science. It was still a favourite dogma, that the fossil
remains of shells and marine creatures were not of
animal origin; an opinion adhered to by many from
their extreme reluctance to believe, that the earth
could have been inhabited by living beings before a
great part of the existing mountains were formed. In
reference to this controversy, Steno had dissected a
shark recently taken from the Mediterranean, and had
demonstrated that its teeth and bones were identical
with many fossils found in Tuscany. He had also
compared the shells discovered in the Italian strata

* QOsserv. sugli Animali aquat. e terrest, 1626.

Ch. IJ. STENO. Ad

with living species, pointed out their resemblance, and
traced the various gradations from shells merely cal-
cined, or which had only lost their animal gluten, to
those petrifactions in which there was a perfect substi-
tution of stony matter. In his division of mineral
masses, he insisted on the secondary origin of those
deposits in which the spoils of animals, or fragments
of older rocks were inclosed. He distinguished between
Marine formations and those of a fluviatile character,
the last containing reeds, grasses, or the trunks and
branches of trees. He argued in favour of the original
horizontality of sedimentary deposits, attributing their
Present inclined and vertical position sometimes to the
€scape of subterranean vapours, heaving the crust of
the earth from below upwards, and sometimes to the
falling in of masses over-lying subterranean cavities.
He declared that he had obtained proof that Tuscany
must successively have acquired six distinct configura-
tions, having been twice covered by water, twice laid
dry with a level, and twice with an irregular and uneven
surface.* He displayed great anxiety to reconcile his
new views with Scripture, for which purpose he pointed
io certain rocks as having been formed before the ex-
tstence of animals and plants ; selecting unfortunately
as examples certain formations of limestone and sand-
Stone in his own country, now known to contain, though
sparingly, the remains of animals and plants, — strata
which do not even rank as the oldest part of our
secondary series, Steno suggested that Moses, when
Speaking of the loftiest mountains as having been
covered by the deluge, meant merely the loftiest of the
hills then existing, which may not have been very high.

* i ha hd . . a i
“a Sex itaque distinctas Etrurie facies agnoscimus, dum bis
ul i . . i
da, bis plana, et sicca, bis aspera fuerit, &c.

42 i SCILLA. [Book I.

The diluvian waters, he supposed, may have issued
from the interior of the earth into which they had
retired, when in the beginning the land was separated
from the sea. These, and other hypotheses on the
same subject, are not calculated to enhance the value
of the treatise, and could scarely fail to detract from
the authority of those opinions which were sound and
legitimate deductions from fact and observation. They
have served, nevertheless, as the germs of many popu-
lar theories of later times, and in an expanded form
have been put forth as original inventions by some of
our contemporaries.

Scilla, 1670. — Scilla, a Sicilian painter, published,
in 1670, a treatise, in Latin, on the fossils of Calabria,
illustrated by good engravings. This work proves the
continued ascendancy of dogmas often refuted; for we
find the wit and eloquence of the author chiefly directed
against the obstinate incredulity of naturalists as to
the organic nature of fossil shells.* Like many
eminent naturalists of his day, Scilla gave way to the
popular persuasion, that all fossil shells were the effects
and proofs of the Mosaic deluge. It may be doubted
whether he was perfectly sincere, and some of his con-
temporaries who took the same course were certainly
not so. But so eager were they to root out what they
justly considered an absurd prejudice respecting the
nature of organized fossils, that they seem to have
been ready to make any concessions, in order to

SS ee ee E
et

* Scilla quotes the remark of Cicero on the story that a stone in
Chios had been cleft open, and presented the head of Paniscus in
relief : — “ I believe,” said the orator, “ that the figure bore some
resemblance to Paniscus, but not such that you would have deemed
it sculptured by Scopas; for chance never perfectly imitates the
truth.”

ea

Ch. IL] DILUVIAL THEORY. 43
establish this preliminary point. Such a compfomising
policy was short-sighted, since it was to little purpose
that the nature of the documents should at length be
correctly understood, if men were to be prevented
from deducing fair conclusions from them.

Diluvial Theory. — The theologians who now en-
tered the field in Italy, Germany, France, and England,
were innumerable; and henceforward, they who refused
to subscribe to the position, that all marine organic re-
mains were proofs of the Mosaic deluge, were exposed
to the imputation of disbelieving the whole of the
Sacred writings. Scarcely any step had been made in
aPproximating to sound theories since the time of
racastoro, more than a hundred years having been
lost, in writing down the dogma that organized fossils
Were mere sports of nature. An additional period of
à century and a half was now destined to be consumed

in exploding the hypothesis, that organized fossils had
all been buried in the solid strata by the Noachian
flood. Never did a theoretical fallacy, in any branch

of Science, interfere more seriously with accurate

Observation and the systematic classification of facts.
n recent times, we may attribute our rapid progress
chiefly to the careful determination of the order of
Succession in mineral masses, by means of their
different organic contents, and their regular super-
Position. But the old diluvialists were induced by
their system to confound all the groups of strata to-
gether instead of discriminating, — to refer all appear-
ances to one cause and to one brief period, not to a
variety of causes acting throughout a long succession
of epochs. They saw the phenomena only as they
desired to see them, sometimes misrepresenting facts,

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4A. DILUVIAL THEORY — QUIRINI. [Book I.

and at other times deducing false conclusions from
correct data. Under the influence of such prejudices,
three centuries were of as little avail as a few years
in our own times, when we are no longer required
to propel the vessel against the force of an adverse
current.

It may be well, therefore, to forewarn the reader,
that in tracing the history of geology from the close of
the seventeenth to the end of the eighteenth century,
he must expect to be occupied with accounts of the
retardation, as well as of the advance of the science.
It will be necessary to point out the frequent revival
of exploded errors, and the relapse from sound to the
most absurd opinions; and to dwell on futile reasoning
and visionary hypothesis, because some of the most
extravagant systems were invented or controverted by
men of acknowledged talent. In short, a sketch of the
progress of geology is the history of a constant and
violent struggle between new opinions and ancient
doctrines, sanctioned by the implicit faith of many ge-
nerations, and supposed to rest on scriptural authority.
The inquiry, therefore, although highly interesting to
one who studies the philosophy of the human mind, is
too often barren of instruction to him who searches for
truths in physical science.

Quirini, 1676. — Quirini, in 1676*, contended, in
opposition to Scilla, that the diluvian waters could not
have conveyed heavy bodies to the summit of moun-
tains, since the agitation of the sea never (as Boyle
had demonstrated) extended to great depths +; and

has os: Testaceis fossilibus Mus. Septaliani.

+ The opinions of Boyle, alluded to by Quirini, were published
a few years before, in a short article entitled « On the Bottom of
the Sea.” From observations collected from the divers of the pearl

Ch. TIL] ' PLOT — LISTER. 45

x

still less could the testacea, as some pretended, have
lived in these diluvian waters; for “ the duration of the
flood was brief, and the heavy rains must have destroyed
the saltness of the sea!” He was the first writer who
ventured to maintain that the universality of the
Noachian cataclysm ought not to be insisted upon. As
to the nature of petrified shells, he conceived that as
earthy particles united in the sea to form the shells of
mollusca, the same crystallizing process might be ef-
fected on the land; and that, in the latter case, the
Setms of the animals might have been disseminated
through the substance of the rocks, and afterwards
developed by virtue of humidity. Visionary as was
this doctrine, it gained many proselytes even amongst
the more sober reasoners of Italy and Germany; for it
conceded that the position of fossil bodies could not
© accounted for by the diluvial theory.

Plot — Lister, 1678.— In the mean time, the doc-
trine that fossil shells had never belonged to real
animals maintained its ground in England, where
the agitation of the question began at a much later
Period. Dr. Plot, in his “ Natural History of Oxford-
shire” (1677), attributed to a “ plastic virtue latent
in the earth” the origin of fossil shells and fishes; and

ister, to his accurate account of British shells, in
1678, added the fossil species, under the appellation of

fishery, Boyle inferred that, when the waves were six or seven feet

high above the surface of the water, there were no signs of agit-
ation at the depth of fifteen fathoms ; and that even during heavy
pals OMe ste okon of tie water waa exceedingly diminished

at the depth of twelve or fifteen feet. He had also learnt from
some of his informants

Site directions at diffe
‘London, 1744,

» that there were currents running in oppo-
rent depths. — Boyle’s Works, vol. iii. p.110.

46 i LEIBNITZ. [Book I.

turbinated and bivalve stones. “ Either,’ said he,
«these were terriginous, or, if otherwise, the animals
they so exactly represent have become extinct.” This
writer appears to have been the first who was aware
of the continuity over large districts of the principal
groups of strata in the British series, and who proposed
the construction of regular geological maps.*

Leibnitz, 1680.—The great mathematician Leibnitz
published his “ Protogcea” in 1680. He imagined this
planet to have been originally a burning luminous
mass, which ever since its creation has been un-
dergoing refrigeration. When the outer crust had
cooled down sufficiently to allow the vapours to be
condensed, they fell, and formed a universal ocean,
covering the loftiest mountains, and investing the
whole globe. The crust, as it consolidated from a
state of fusion, assumed a vesicular and cavernous
structure; and being rent in some places, allowed the
water to rush into the subterranean hollows, whereby
the level of the primeval ocean was lowered. The
breaking in of these vast caverns is supposed to have
given rise to the dislocated and deranged position
of the strata “which Steno had described,” and the
same disruptions communicated violent movements to
the incumbent waters, whence great inundations en-
sued. The waters, after they had been thus agitated,
deposited their sedimentary matter during intervals of
quiescence, and hence the various stony and earthy
strata. “ We may recognize, therefore,” says Leibnitz,
a double origin of primitive masses, the one by refri-
geration from igneous fusion, the other by concretion

* See Mr. Conybeare’s excellent Introduction to the “ Outlines
of the Geology of England and Wales,” p. 12.

Ch. IIL] HOOKE. . 47

from aqueous solution,” * By the repetition of similar
causes (the disruption of the crust and consequent
floods), alternations of new strata were produced, until
at length these causes were reduced to a condition of
quiescent equilibrium, and a more permanent state of
things was established.t
ooke, 1688.— The “ Posthumous Works of Robert
ooke, M.D.,” well known as a great mathematician
and natural philosopher, appeared in 1705, containing
“A Discourse of Earthquakes,” which, we are in-
°rmed by his editor, was written in 1668, but revised
at subsequent periods.{ Hooke frequently refers to
the best Italian and English authors who wrote before
is time on geological subjects; but there are no pas-
Sages in his works implying that he participated in the
enlarged views of Steno and Lister, or of his contem-
Porary, Woodward, in regard to the geographical ex-

tent of certain groups of strata. His treatise, however,
8 the most philosophical production of that age, in
regard to the causes of former changes in the organic
and inorganic kingdoms of nature.

Owever trivial a thing,” he says, “ a rotten shell
May appear to some, yet these monuments of nature

* S ih = x
Unde Jam duplex origo intelligitur primorum corporum, una,
cum ab ignis fusione refrigescerent, altera, cum reconcrescerent
S solutione aquarum.

t Redeunte mox simili causa strata subinde alia aliis impone-
Tentan et facies teneri adhuc orbis sepius novata est. Donec
quiescentibus Causis, atque æquilibratis, consistentior emergeret
verum status. — For an able analysis of the views of Leibnitz, in
a Protogæa, see Mr. Conybeare’s Report to the Brit. Assoc. on
the Progress of Geological Science, 1832.

ł Between the year 1688 and his death, in 1703, he read several |
memoirs to the Royal Society, and delivered lectures on various

Subjects, relating to fossil remains and the effects of earthquakes.

a

Fe EE aE aE ee

48 HOOKE ON EXTINCT SPECIES. [Book I.

are more certain tokens of antiquity than coins or
medals, since the best of those may be counterfeited
or made by art and design, as may also books, manu-
scripts, and inscriptions, as all the learned are now
sufficiently satisfied has often been actually practised,”
&c.; “and though it must be granted that it is very
difficult to read them (the records of nature) and
to raise a chronology out of them, and to state the
intervals of the time wherein such or such cata-
strophes and mutations have happened, yet it is not
impossible.”*

Respecting the extinction of species, Hooke was
aware that the fossil ammonites, nautili, and many other
shells and fossil skeletons found in England, were of
different species from any then known ; but he doubted
whether the species had become extinct, observing
that the knowledge of naturalists of all the marine
species, especially those inhabiting the deep sea, was
very deficient. In some parts of his writings, however,
he leans to the opinion that species had been lost ; and
in speculating on this subject, he even suggests that
there might be some connection between the disap-
pearance of certain kinds of animals and plants, and
the changes wrought by earthquakes in former ages.
Some species, he observes with great sagacity, are
« peculiar to certain places, and not to be found else-
where. If, then, such a place had been swallowed up,
it is not improbable but that those animate beings may
have been destroyed with it ; and this may be true both
of aérial and aquatic animals: for those animated
bodies, whether vegetables or animals, which were
naturally nourished or refreshed by the air, would be

* Posth. Works, Lecture, Feb. 29. 1688.

Ch. 11] HOOKE ON EXTINCT SPECIES. 49

destroyed by the water,” &c.* Turtles, he adds, and
such large ammonites as are found in Portland, seem
to have been the productions of hotter countries; and
it is necessary to suppose that England once lay under
the sea within the torrid zone! To explain this and
Similar phenomena, he indulges in a variety of specula-
tions concerning changes in the position of the axis of
the €arth’s rotation, “a shifting of the earth’s centre
of gravity, analogous to the revolutions of the magnetic
Pole,” &c. None of these conjectures, however, are
Proposed dogmatically, but rather in the hope of pro-
Moting fresh inquiries and experiments.

In Opposition to the prejudices of his age, we find
him arguing against the idea that nature had formed
fossil bodies “for no other end than to play the mimic
in the mineral kingdom ; ” — maintaining that figured
Stones were “really the several bodies they represent,
or the mouldings of them petrified,” and “ not as some
have imagined, ‘a lusus nature,’ sporting herself in

the needless formation of useless beings.”}

* Posth. Works, p. 327.

t Posth. Works, Lecture, Feb. 15. 1688, Hooke explained,
With considerable clearness, the different modes wherein organic
substances may become lapidified ; and, among other illustrations,
he mentions some silicified palm-wood brought from Africa, on
Which M. de la Hire had read a memoir to the Royal Academy
of France (June, 1692), wherein he had pointed out, not only the
tubes running the length of the trunk, but the roots at one ex-
tremity. De la Hire, says Hooke, also treated of certain trees
found petrified in « the river that passes by Bakan, in the king-
dom of 4va, and which has for the space of ten leagues the virtue
of petrifying wood,” It is an interesting fact, that the silicified
wood of the Irawadi should have attracted attention more than one

hundred years ago. - Remarkable discoveries have been recently
VOL. I. 5

50 HOOKE ON EARTHQUAKES. [Book I.

It was objected. to Hooke, that his doctrine of the
extinction of species derogated from the wisdom and
power of the Omnipotent Creator ; but he answered,
that, as individuals die, there may be some termination
to the duration of a species; and his opinions, he
declared, were not repugnant to Holy Writ: for the
Scriptures taught that our system was degenerating,
and tending to its final dissolution ; “ and as, when that
shall happen, all the species will be lost, why not some
at one time and some at another ?” *

But his principal object was to account ie the
manner in which shells had been conveyed into the
higher parts of “the Alps, Apennines, and Pyrenean
hills, and the interior of continents in general.” These
and other appearances, he said, might have been
brought about by earthquakes, “ which have turned
plains into mountains, and mountains into plains, seas
into land, and land into seas, made rivers where there
were none before, and swallowed up others that for-
merly were, &c. &c.; and which, since the creation of
the world, have wrought many great changes on the
superficial parts of the earth, and have been the in-
struments of placing shells, bones, plants, fishes, and
the like, in those places where, with much astonish-
ment, we find them.”+ This doctrine, it is true, had
been laid down in terms almost equally explicit by
Strabo, to explain the occurrence of fossil shells in
the interior of continents, and to that geographer,

made there of fossil animals and vegetables, by Mr. Crawfurd and
Dr. Wallich. — See Geol, Trans. vol. ii. part iii. p. 377. second
series. De la Hire cites Father Duchatz, in the second volume
of “ Observations made in the Indies by the Jesuits.”

* Posth. Works, Lecture May 29. 1689. + Posth. Works, p. 312.

Ch, III] HOOKE’S DILUVIAL THEORY. 51

and other writers of antiquity, Hooke frequently re-
fers; but the revival and development of the system
was an important step in the progress of modern
Science,

Hooke enumerated all the examples known to him
of Subterranean disturbance, from “the sad catastrophe
of Sodom and Gomorrah” down to the Chilian earth-
quake of 1646. The elevating of the bottom of the
Sea, the sinking and submersion of the land, and most
of the inequalities of the earth’s surface, might, he
said, be accounted for by the agency of these sub-
terranean cause: Hie: mentions that the coast near

aples was raised during the eruption of Monte Nuovo ;
and that, in 1591, land rose in the island of St. Michael,

uring an eruption ; and although it would be more
difficult, he says, to prove, he does not doubt but that
there had been as many earthquakes in the parts of
the earth under the ocean, as in the parts of the dry
and; in confirmation of which, he mentions the im-
Measurable depth of the sea near some volcanos. To
attest the extent of simultaneous subterranean move-
ments, he refers to an earthquake in the West Indies,
In the year 1690, where the space of earth raised, or
“struck upwards,” by the shock, exceeded, he affirms,
the length of the Alps and the Pyrenees.

Hookes: diluvial theory. — As Hooke declared the
favorite hypothesis: of the day, “ that marine fossi]

bod

odies were to be referred to Noah’s flood,” to be

wholly untenable, he appears to have felt himself

called upon to subs

titute a diluvial theory of his own,
and thus he becani

e involved in countless difficulties
and Contradictions, « During the great catastrophe,”
he said, “there might have been a changing of that
Part which was before dry land into sea by sinking,
D2

52 HOOKE — RAY. [Book I.

and of that which was sea into dry land by raising, and
marine bodies might have been buried in sediment
beneath the ocean, in the interval between the creation
and the deluge.”* Then follows a disquisition on the
separation of the land from the waters, mentioned in
Genesis: during which operation some places of the
shell of the earth were forced outwards, and others
pressed downwards or inwards, &c. His diluvial hy-
pothesis very much resembled that of Steno, and was
entirely opposed to the fundamental principles pro-
fessed by him, thathe would explain the former changes
of the earth in a more natural manner than others had
done. When, in despite of this declaration, he required
a former “crisis of nature,” and taught that earth-
quakes had become debilitated, and that the Alps,
Andes, and other chains, had been lifted up in a few
months, he was compelled to assume so rapid a rate of

change, that his machinery appeared scarcely less ex-

travagant than that of his most fanciful predecessors.
For this reason, perhaps, his whole theory of earth-
quakes met with undeserved neglect.

Ray, 1692.— One of his contemporaries, the cele-
brated naturalist, Ray, participated in the same desire
to explain geological phenomena, by reference to causes
less hypothetical than those usually resarted te.t In
his essay on “ Chaos and Creation,” he proposed a
system, agreeing in its outline, and in many of its
details, with that of Hooke; but his knowledge of

* Posth. Works, p. 410.

+ Ray’s Physico-theological Discourses were of somewhat later
date than Hooke’s great work on earthquakes. He speaks of
Hooke as one “ whom for his learning and deep insight into the
mysteries of nature he deservedly honoured.” — On the Deluge,

chap. iv.

Ch. IIL] RAY. 53

natural history enabled him to elucidate the subject

with various original observations. Earthquakes, he

suggested, might have been the second causes em-

ployed at the creation, in separating the land from the

waters, and in gathering the waters together into one

Place. He mentions, like Hooke, the earthquake of
1646; which had violently shaken the Andes for some

hundreds of leagues, and made many alterations therein.

Tn assigning a cause for the general deluge, he pre-

ferred a change in the earth’s centre of gravity to the '
introduction of earthquakes. Some unknown cause,
he said, might have forced the subterranean waters

outwards, as was, perhaps, indicated by “ the breaking

Up of the fountains of the great deep.”

Ray was one of the first of our writers who enlarged
Upon the effects of running water upon the land, and
of the encroachment of the sea upon the shores. So
important did he consider the agency of these causes,
that he saw in them an indication of the tendency of
our system to its final dissolution; and he wondered
why the earth did not proceed more rapidly towards a
Seneral submersion beneath the sea, when so much
Matter was carried down by rivers, or undermined in
the sea-cliffs. We perceive clearly from his writings,
that the gradual decline of our system, and its future
Consummation by fire, was held to be as necessary an
article of faith by the orthodox, as was the recent
origin of our planet. His discourses, like those of
Hooke, are highly interesting, as attesting the familiar
association in the minds of philosophers, in the age of
Newton, of questions in physics and divinity. Ray
Save an unequivocal proof of the sincerity of his mind,
by sacrificing his preferment in the church, rather than
take an oath against the Covenanters, which he could

D 3

54 WOODWARD. [Book 1.

not reconcile with his conscience. His reputation,
moreover, in the scientific world placed him high above
the temptation of courting popularity, by pandering to
the physico-theological taste of his age. It is, there-
fore, curious to meet with so many citations from the
Christian fathers and prophets in his essays on physical
science — to find him in one page proceeding, by the
strict rules of induction, to explain the former changes
of the globe, and in the next gravely entertaining the
question, whether the sun and stars, and the whole
heavens shall be annihilated, together with the earth,
at the era of the grand conflagration.

Woodward, 1695. — Among the contemporaries of
Hooke and Ray, Woodward, a professor of medicine,
had acquired the most extensive information respecting
the geological structure of the crust of the earth. He
had examined many parts of the British strata with
minute attention; and his systematic collection of spe-
cimens, bequeathed to the University of Cambridge,
and still preserved there as arranged by him, shows
how far he had advanced in ascertaining the order of
superposition. From the great number of facts col-
lected by him, we might have expected his theoretical
views to be more sound and enlarged than those of his
contemporaries; but in his anxiety to accommodate all
observed phenomena to the scriptural account of the
Creation and Deluge, he arrived at most erroneous
results. He conceived “the whole terrestrial globe
to have been taken to pieces and dissolved at the flood,
and the strata to have settled down from this promis-
cuous mass as any earthy sediment from a fluid.”* In
corroboration of these views, he insisted upon the fact,
that “marine bodies are lodged in the strata according

* Essay towards a Natural History of the Earth, 1695. Preface.

Ch. 111] BURNET. _ 55

to the order of their gravity, the heavier shells in stone,
the lighter in chalk, and so of the rest.”* Ray im-
mediately exposed the unfounded nature of this asser-
tion, remarking truly, that fossil bodies “are often
mingled, heavy with light, in the same stratum ;” and
e even went so far as to say, that Woodward “must
have invented the phenomena for the sake of confirm-
ing his bold and strange hypothesis +” — a strong
€xpression from the pen of a contemporary.
Burnet, 1690. — At the same time Burnet published
his « Theory of the Earth.” { The title is most cha-
Tacteristic of the age, — “ The Sacred Theory of the
Earth ; containing an Account of the Original of the
Earth, and of all the general Changes which it hath
already undergone, or is to undergo, till the Consum-
mation of all Things.” Even Milton had scarcely
ventured in his poem to indulge his imagination s0
freely in painting scenes of the Creation and Deluge,
Paradise and Chaos. He explained why the primeval
earth enjoyed a perpetual spring before the flood !
showed how the crust of the globe was fissured by
“the sun’s rays,” so that it burst, and thus the diluvial
Waters were let loose from a supposed central abyss.
Not satisfied with these themes, he derived from the
books of the inspired writers, and even from heathen
authorities, prophetic views of the future revolutions
of the globe, gave a most terrific description of the
_ Seneral conflagration, and proved that a new heaven
and a new earth will rise out of a second chaos — after
which will follow the blessed millennium.

* Essay towards a Natural History of the Earth, 1695. Preface.
si Consequences of the Deluge, p. 165.
ł First published in Latin between the years 1680 and 1690.

D 4

56 BURNET — WHISTON. [Book I.

The reader should be informed, that, according to
the opinion of many respectable writers of that age,
there was good scriptural ground for presuming that
the garden bestowed upon our first parents was not on
the earth itself, but above the clouds, in the middle
region between our planet and the moon. Burnet
approaches with becoming gravity the discussion of so
important a topic. He was willing to concede that
the geographical position of Paradise was not in Meso-
potamia, yet he maintained that it was upon the earth,
and in the southern hemisphere, near the equinoctial
line. Butler selected this conceit as a fair mark for
his satire, when, amongst the numerous accomplish-
ments of Hudibras, he says, —

He knew the seat of Paradise,
Could tell in what degree it lies ;

And, as he was disposed, could prove it
Below the moon, or else above it.

Yet the same monarch, who is said never to have slept
without Butler’s poem under his pillow, was so great
an admirer and patron of Burnet’s book, that he ordered
it to be translated from the Latin into English. The
style of the “Sacred Theory” was eloquent, and the

book displayed powers of invention of no ordin
stamp. It was, in fact, a fine historical romance, as
Buffon afterwards declared: but it was treated asa
work of profound science in the time of its author, and
was panegyrized by Addison in a Latin ode, while
Steele praised it in the “ Spectator.” Towards the
end of the last century, Warton, in his « Essay on
Pope,” discovered that Burnet united the faculty of
judgment with powers of imagination,

Whiston, 1696. — Another production of the same
school, and equally characteristic of the time, was that

ary

Ch. 111] WHISTON. 57

of Whiston, entitled, « A New Theory of the Earth ;
wherein the Creation of the World in Six Days, the
Universal Deluge, and the General Conflagration, as
laid down in the Holy Scriptures, are shewn to be
perfectly agreeable to Reason and Philosophy.” + He
Was at first a follower of Burnet; but his faith in the
infallibility of that writer was shaken by the declared
Opinion of Newton, that there was every presumption
in astronomy against any former change in the inclin-
ation of the earth’s axis. This was a leading dogma in
Burnet’s system, though not original, for it was bor-
Towed from an Italian, Alessandro degli Alessandri,
who had suggested it in the beginning of the fifteenth
century, to account for the former occupation of the
Present continents by the sea. La Place has since
Strengthened the arguments of Newton, against the
Probability of any former revolution of this kind.

The remarkable comet of 1680 was fresh in the
memory of every one when Whiston first began his
Cosmological studies, and the principal novelty of his
Speculations consisted in attributing the deluge to the
near approach to the earth of one of these erratic

dies, Having ascribed an increase of the waters to
this Source, he adopted Woodward’s theory, supposing
all Stratified deposits to have resulted from the
“chaotic sediment of the flood.” Whiston was one of
the first who ventured to propose that the text of Ge-
nesis should be interpreted differently from its ordinary
acceptation, so that the doctrine of the earth having
existed long previous to the creation of man might no
longer be regarded as unorthodox. He had the art to
throw an air of plausibility over the most improbable
Parts of his theory, and seemed to be proceeding in the
Most sober manner, and by the aid of mathematical

DS

58 HUTCHINSON — CELSIUS — SCHEUCHZER. [Book I.

demonstration, to the establishment of his various
propositions. Locke pronounced a panegyric on his
theory, commending him for having explained so many
wonderful and before inexplicable things. His book,
as well as Burnet’s, was attacked and refuted by
Keill.* Like all who introduced purely hypothetical
causes to account for natural phenomena, Whiston
retarded the progress of truth, diverting men from the
investigation of the laws of sublunary nature, and in-
ducing them to waste time in speculations on the
power of comets to drag the waters of the ocean over
the land—on the condensation of the vapours of their
tails into water, and other matters equally edifying.

` Hutchinson, 1724.—John Hutchinson, who had
been employed by Woodward in making his collection
of fossils, published afterwards, in 1724, the first part
of his “ Moses’s Principia,” wherein he ridiculed
Woodward’s hypothesis. He and his numerous fol-
lowers were accustomed to declaim loudly against
human learning ; and they maintained that the Hebrew
scriptures, when rightly translated, comprised a perfect
system of natural philosophy, for which reason they
objected to the Newtonian theory of gravitation.

Celsius. — Andrea Celsius, the Swedish astronomer,
published about this time his remarks on the gradual
diminution and sinking of the waters in the Baltic, to
which I shall have occasion to advert more particularly
in the second volume (ch. 17. book 2.).

Scheuchzer, 1708.—In Germany, in the mean time,
Scheuchzer laboured to prove, in a work entitled “ The
Complaint of the Fishes” (1708), that the earth had
been remodelled at the deluge. Pluche, also, in 1732,
wrote to the same effect ; while Holbach, in 1753, after

+ An Examination of Dr. Burnet’s Theory, &c. 2d ed. 1734.

Ch. IIL] ITALIAN GEOLOGISTS — VALLISNERI. 59

considering the various attempts to refer all the ancient
formations to the Noachian flood, exposed the in-
adequacy of this cause.

Ttalian Geologists — Vallisneri.—1 return with
pleasure to the geologists of Italy, who preceded, as
has been already shown, the naturalists of other coun-
tries in their investigations into the ancient history
of the earth, and who still maintained a decided pre-
eminence. They refuted and ridiculed the physico-
theological systems of Burnet, Whiston, and Wood-
ward*; while Vallisneri+, in his comments on the
Woodwardian theory, remarked how much the interests
of religion, as well as those of sound philosophy, had
suffered by perpetually mixing up the sacred writings
With questions in physical science. The works of this
author were rich in original observations. He at-
tempted the first general sketch of the marine deposits
of Italy, their geographical extent, and most charac-
teristic organic remains. In his treatise “On the
origin of Springs,” he explained their dependence on
the order, and often on the dislocations, of the strata,
and reasoned philosophically against the opinions of
those who regarded the disordered state of the earth’s
crust as exhibiting signs of the wrath of God for the
sins of man. He found himself under the necessity of
contending, in his preliminary chapter, against St.
Jerome, and four other principal interpreters of
Scripture, besides several professors of divinity, “that

* Ramazzinieven asserted, that the ideas of Burnet were mainly
borrowed from a dialogue of one Patrizio; but Brocchi, after
reading that dialogue, assures us, that there was scarcely any other
Correspondence between these systems, except that both were
equally whimsical.

t Dei Corpi Marini, Lettere critiche, &c. 1721.

D 6

60 ITALIAN GEOLOGISTS — MORO. [Book I.

‘springs did not flow by subterranean siphons and
cavities from the sea upwards, losing their saltness in
the passage,” for this theory had been made to rest
on the infallible testimony of Holy Writ.

Although reluctant to generalize on the rich mate-
rials accumulated in his travels, Vallisneri had been so
much struck with the remarkable continuity of the
‘more recent marine strata, from one end of Italy to
the other, that he came to the conclusion that the
ocean formerly extended over the whole earth, and
after abiding there for a long time, had gradually sub-
sided. This opinion, however untenable, was a great
step beyond Woodward's diluvian hypothesis, against
which Vallisneri, and after him all the Tuscan geolo-
gists, uniformly contended, while it was warmly sup-
ported by the members of the Institute of Bologna.*

Among others of that day, Spada, a priest of Grez-
zana, in 1737, wrote to prove that the petrified marine
bodies near Verona were not diluvian.+ Mattani
drew a similar inference from the shells of Volterra
and other places: while Costantini, on the other hand,
whose observations on the valley of the Brenta and
‘other districts were not without value, undertook to
vindicate the truth of the deluge, as also to prove that
Italy had been peopled by the descendants of Japhet.

Moro, 1740.— Lazzaro Moro, in his work (published
in 1740) “ On the Marine Bodies which are found in
the Mountains §,” attempted to apply the theory of
earthquakes, as expounded by Strabo, Pliny, and
other ancient authors, with whom he was familiar, to
the geological phenomena described by Vallisneri.|

* Brocchi, p. 28. t Ibid. p. 33, t Ibid, p. 37.

§ Sui Crostacei ed altri Corpi Marini che si trovano sui Monti.
| Moro does not cite the works of Hooke and Ray; and

Ch. 11L] LAZZARO MORO. 61
His attention was awakened to the elevating power of
Subterranean forces by a remarkable phenomenon
which happened in his own time, and which had also
been noticed by Vallisneri in his letters. A new
island rose in 1707 from a deep part of the sea
near Santorin in the Mediterranean, during continued
Shocks of an earthquake, and, increasing rapidly in
size, grew in less than a month to be half a mile in
circumference, and about twenty-five feet above high-
Water mark. It was soon afterwards covered by vol-
Canic ejections, but, when first examined, it was found
to be a white rock, bearing on its surface living oysters
and crustacea. In order to ridicule the various theories
then in vogue, Moro ingeniously supposes the arrival
on this new island of a party of naturalists ignorant of
its recent origin. One immediately points to the
Marine shells, as proofs of the universal deluge ; another
argues that they demonstrate the former residence of

le sea upon the mountains ; a third dismisses them
as mere sports of nature; while a fourth affirms, that
Eiey were born. and .nourished. within. the rock. in
ancient caverns, into which salt water had been raised
in the shape of vapour by the action of subterranean
heat,

Moro pointed with great judgment to the faults and
dislocations of the strata described by Vallisneri, in
the Alps and other chains, in confirmation of his

d

Octrine, that the continents had been heaved up by

although so Many of his views were in accordance with theirs, he
was probably ignorant of their writings, for they had not been
‘translated. As he always refers to the Latin edition of Burnet,

‘and a French translation of Woodward, we LES
did not read English.

62 GENERELLI’S EXPOSITION OF [Book I.

subterranean movements. He objected, on solid
grounds, to the hypotheses of Burnet and of Wood-
ward; yet he ventured so far to disregard the protest
of Vallisneri, as to undertake the adaptation of every
part of his own system to the Mosaic account of the
creation. On the third day, he said, the globe was
every where covered to the same depth by fresh water;
and when it pleased the Supreme Being that the dry
land should appear, volcanic explosions broke up the
smooth and regular surface of the earth composed of
primary rocks. These rose in mountain masses above
the waves, and allowed melted metals and salts to
ascend through fissures. The sea gradually acquired
its saltness from volcanic exhalations, and, while it
became more circumscribed in area, increased in
depth. Sand and ashes ejected by volcanos were
regularly disposed along the bottom of the ocean, and
formed the secondary strata, which in their turn were
lifted up by earthquakes. We need not follow this
author in tracing the progress of the creation of vege-
tables and animals on the other days of creation ; but,
upon the whole, it may be remarked, that few of the
old cosmological theories had been conceived with so
little violation of known analogies.

Generelli’s illustrations of Moro, 1749.—The style
of Moro was extremely prolix, and, like Hutton, who,
at a later period, advanced many of the same views, he
stood in need of an illustrator. The Scotch geologist
was hardly more fortunate in the advocacy of Playfair,
than was Moro in numbering amongst his admirers
Cirillo Generelli, who, nine years afterwards, delivered
at a sitting of Academicians at Cremona a spirited ex-
position of his theory. This learned Carmelitan friar
does not pretend to have been an. original observer,

Ch. 111] `. LAZZARO MORO'’S THEORY. 63

but he had studied sufficiently to enable him to confirm
the opinions of Moro by arguments from other writers;
and his selection of the doctrines then best established
is so judicious, that a brief abstract of them cannot
fail to be acceptable, as illustrating the state of geology
in Europe, and in Italy in particular, before the middle
of the last century.

The bowels of the earth, says he, have carefully
Preserved the memorials of past events, and this truth
the marine productions so frequent in the hills attest.
From the reflections of Lazzaro Moro, we may assure
Ourselves that these are the effects of earthquakes in
Past times, which have changed vast spaces of sea into
terra firma, and inhabited lands into seas. In this,
More than in any other department of physics, are
observations and experiments indispensable, and we
must diligently consider facts. The land is known,
wherever we make excavations, to be composed of
different strata or soils placed one above the other,
Some of sand, some of rock, some of chalk, others of
marl, coal, pumice, gypsum, lime, and the rest. These
Msgredients are sometimes pure, and sometimes con-
fusedly intermixed. Within are often imprisoned dif-
ferent marine fishes, like dried mummies, and more
frequently shells, crustacea, corals, plants, &c., not
only in Italy, but in France, Germany, England, Africa,
Asia, and America; — sometimes in the lowest, some-
times in the loftiest beds of the earth, some upon the
Mountains, some in deep mines, others near the sea,
and others hundreds of miles distant from it. Wood-
ward conjectured that these marine bodies might
be found every where; but there are rocks in which
none of them occur, as is sufficiently attested by
Vallisneri and Marsilli. The remains of fossil ani-

64 GENERELLI’S EXPOSITION OF [Book I.

mals consist chiefly of their more solid parts, and
the most rocky strata must have been soft when
such exuvie were inclosed in them. Vegetable pro-
„ductions are found in different states of maturity, in-
dicating that they were imbedded in different seasons.
Elephants, elks, and other terrestrial quadrupeds, have
been found in England and elsewhere, in superficial
strata, never covered by the sea. Alternations are
rare, yet not without example, of marine strata, and
those which contain marshy and terrestrial productions.
Marine animals are arranged in the subterraneous beds
with admirable order, in distinct groups, oysters here,
dentalia or corals there, &c., as now, according to
Marsilli*, on the shores of the Adriatic. We must
abandon the doctrine, once so popular, which denies
that organized fossils were derived from living beings,
and we cannot account for their present position by the
ancient theory of Strabo, nor by that of Leibnitz, nor
by the universal deluge, as explained by Woodward
and others: ‘nor is it reasonable to call the Deity
capriciously upon the stage, and to make him work
miracles for the sake of confirming our preconceived
hypotheses.’ —“I hold in utter abomination, most
learned Academicians! those systems which are built
with their foundations in the air, and cannot be propped
up without a miracle; and I undertake, with the as-
sistance of Moro, to explain to you how these marine
animals were transported into the mountains by natural
causes.” t

i
|i

* Saggio fisico intorno alla Storia del Mare, part i. p. 24:
+ “ Abbomino al sommo qualsivoglia sistema,

che sia di pianta
fabbricato in aria; massime quando è tale, che non possa soste-

nersi senza un miracolo,” &c. — De’ Crostacei e di altre Produz.
del Mare, &c. 1749:

ee Sass

a E
i ELIE CEL EE

a

Ch, II] LAZZARO MORO’S THEORY. 65

A brief abstract then follows of Moro’s theory, by
which, says Generelli, we may explain all the phe-
nomena, as Vallisneri so ardently desired, “without
violence, without fictions, without hypotheses, without
miracles.’ * The Carmelitan then proceeds to struggle .
against an obvious objection to Moro’s system, consi-
dered as a method of explaining the revolutions of the
earth, naturally. If earthquakes have been the agents
of such mighty changes, how does it happen that their
effects since the times of history have been so incon-
siderable? This same difficulty had, as we have seen,
Presented itself to Hooke, half a century before, and
forced him to resort to a former “crisis of nature :”
but Generelli defended his position by showing how
numerous were the accounts of eruptions and earth-
quakes, of new islands, and of elevations and sub-
Sidences of land, and yet how much greater a number
of like events must have been unattested and unre-
Corded during the last six thousand years. He also
appealed to Vallisneri as an authority to prove that
the mineral masses containing shells bore, upon the
Whole, but a small proportion to those rocks which
Were destitute of organic remains ; and the latter, says
the learned monk, might have been created as they
NOW exist, in the beginning: |

Generelli then describes the continual waste of
mountains and continents, by the action of rivers and
torrents, and concludes with these eloquent and original
observations : «Is it possible that this waste should
have continued for six thousand, and perhaps a greater
number of years, and that the mountains should re-
main so great, unless their ruins have been’ repaired ?

* 6 ; ears . ira-
: Senza Violenze, senza finzioni, senza supposti, senza mira
coli,” 2 n K

De’ Crostacei e di altre Produz, del Mare, &c. 1749.

66 LAZZARO MORO’S THEORY. [Book 1.

Is it credible that the Author of Nature should have
founded the world upon such laws, as that the dry
land should for ever be growing smaller, and at last
become wholly submerged beneath the waters? Is it
credible that, amid so many created things, the moun-
tains alone should daily diminish in number and bulk,
without there being any repair of their losses? This
would be contrary to that order of Providence which
is seen to reign in all other things in the universe.
Wherefore I deem it just to conclude, that the’same
cause which, in the beginning of time, raised moun-
tains from the abyss, has down to the present day con-
tinued to produce others, in order to restore from time
to time the losses of all such as sink down in different
places, or are rent asunder, or in other way suffer dis-
integration. If this be admitted, we can easily under-
stand why there should now be found upon many
mountains so great a number of crustacea and other
marine animals.”

In the above extract I have not merely enumerated
the opinions and facts which are confirmed by recent
observation, suppressing all that has since proved to
be erroneous, but have given a faithful abridgment
of the entire treatise, with the omission only of
Moro’s hypothesis, which Generelli adopted, with
all its faults and excellencies. The reader will there-
fore remark, that although this admirable essay em-
braces so large a portion of the principal objects
of geological research, it makes no allusion to the
extinction of certain classes of animals; and it. is
evident that no opinions on this head had, at that
time, gained a firm footing in Italy. That Lister and
other English naturalists should long before have de-
clared in favour of the loss of Species, while Scilla and

Ch. 111.9 MARSILULL 67

most of his countrymen hesitated, was perhaps natural,
since the Italian museums were filled with fossil shells
belonging to species of which a great portion did
actually exist in the Mediterranean; whereas the
English collectors could obtain no recent species from
Such of their own strata as were then explored.

The weakest point in Moro’s system consisted in
deriving all the stratified rocks from volcanic ejections;
an absurdity which his opponents took care to expose,
Especially Vito Amici.* Moro seems to have been
misled by his anxious desire to represent the formation
of Secondary rocks as having occupied an extremely
Short period, while at the same time he wished to
employ known agents in nature. To imagine torrents,
vers, currents, partial floods, and all the operations
of Moving water, to have gone on exerting an energy
Many thousand times greater than at present, would
have appeared preposterous and. incredible, and would
have required a hundred violent hypotheses ; but we
are so unacquainted with the true sources of subter-
ranean disturbances, that their former violence may in
theory be multiplied indefinitely, without its being
Possible to prove the same manifest contradiction or
absurdity in the conjecture. For this reason, perhaps,

oro preferred to derive the materials of the strata
from volcanic ejections, rather than from transportation
by running water.

Marsili.—Marsilli, whose work is alluded to by
Generelli, had been prompted to institute inquiries
into the bed of the Adriatic, by discovering, in the ter-
ritory of Parma, (what Spada had observed near Verona,
and Schiavo in Sicily,) that fossil shells were not scat-

* Sui Testacei della Sicilia.

68 DONATI — BALDASSARI — BUFFON. [Book 1.

tered through the rocks at random, but disposed in
regular order, according to certain genera and species.

Vitaliano Donati, 1750.— But witha view of throw-
ing further light upon these questions, Donati, in 1750,
undertook a more extensive investigation of the Adri-
atic, and discovered, by numercus soundings, that
deposits of sand, marl, and tufaceous incrustations, most
strictly analogous to those of the Subapennine hills,
were in the act of accumulating there. He ascertained
that there were no shells in some of the submarine
tracts, while in other places they lived together in
families, particularly the genera Arca, Pecten, Venus,
Murex, and some others. ` He also states that in divers
localities he found a mass composed of corals, shells,
and crustaceous bodies of different species, confusedly
blended with earth, sand, and gravel. At the depth
of a foot or more, the organic substances were entirely
petrified and reduced to marble; at less than a foot
from the surface, they approached nearer to their na-
tural state; while at the surface they were alive, or if
dead, in a good state of preservation.

Baldassari.— A contemporary naturalist, Baldassari,
had shown that the organic remains in the tertiary
marls of the Siennese territory were grouped in families,
in a manner precisely similar to that above alluded to
by Donati.

Buffon, 1749. — Buffon first made known his theo-
retical views concerning the former changes of the
earth, in his Natural History, published in 1749. He
adopted the theory of an original volcanic nucleus,
together with the universal ocean of Leibnitz. By this
aqueous envelope the highest mountains were once
covered. Marine currents then acted violently, and
formed horizontal strata, by washing away solid matter

Ch, IIL] BUFFON. 69

in some parts, and depositing it in others; they also
excavated deep submarine valleys. The level of the
ocean was then depressed by the entrance of a part of
its waters into subterranean caverns, and thus some
land was left dry. Buffon seems not to have profited,
like Leibnitz and Moro, by the observations of Steno,
or he could not have imagined that the strata were
Senerally horizontal, and that those which contain
organic remains had never been disturbed since the era
of their formation. He was conscious of the great
Power annually exerted by rivers and marine currents
m transporting earthy materials to lower levels, and he
“ven contemplated the period when they would destroy .
all the present continents. Although in geology he
Was not an original observer, his genius enabled him to
Tender his hypothesis attractive ; and by the eloquence
of his style, and the boldness of his speculations, he
awakened curiosity, and provoked a spirit of inquiry
amongst his countrymen.
Soon after the publication of his “ Natural History,”
m which was included his “ Theory of the Earth,” he
received an official letter (dated January, 1751) from
the Sorbonne, or Faculty of Theology in Paris, inform-
‘ng him that fourteen propositions in his works “ were
*eprehensible, and contrary to the creed of the church.”
he first of these obnoxious passages, and the only one
relating to geology, was as follows : — “ The waters of
the sea have produced the mountains and valleys of
the land — the waters of the heavens, reducing all to a
level, wil] at last deliver the whole land over to the sea,
and the sea, successively prevailing over the land, will
leave dry new continents like those which we inhabit.”

Buffon was invited by the College, in very courteous
terms, to send in an explanation, or rather a recantation,

70 TARGIONI. [Book I.

of his unorthodox opinions. To this he submitted;
and a general assembly of the Faculty having approved
of his “Declaration,” he was required to publish it in
his next work. The document begins with these
words; — “ I declare that I had no intention to contra-
dict the text of Scripture; that I believe most firmly
all therein related about the creation, both as to order
of time and matter of fact; and I abandon every thing
in my book respecting the formation of the earth, and,
generally, all which may be contrary to the narration
of Moses.’ *

The grand principle which Buffon was called upon
to renounce was simply this, —“ that the present moun-
tains and valleys of the earth are due to secondary
causes, and that the same causes will in time destroy all
the continents, hills, and valleys, and reproduce others
like them.” Now, whatever may be the defects of
many of his views, it is no longer controverted that
the present continents are of secondary origin. The
doctrine is as firmly established as the earth’s rotation
on its axis; and that the land now elevated above the
level of the sea will not endure for ever, is an opinion, .
which gains ground daily, in proportion as we enlarge *
our experience of the changes now in progress.

Targioni, 1751. — Targioni, in his voluminous
« Travels in Tuscany, 1751 and 1754,” laboured to fill
up the sketch of the geology of that region left by
Steno sixty years before. Notwithstanding a want of
arrangement and condensation in his memoirs, they
contained a rich store of faithful observations. He has _
not indulged in many general views, but in regard to
the origin of valleys, he was opposed to the theory of
Buffon, who attributed them principally to submarine

* Hist. Nat. tom. v. éd; del’ Imp. Royale, Paris, 1769.

oa

f
a

ee
el

se rc

Se

Ch mL] LEHMAN — GESNER. 71
The Tuscan naturalist laboured to show
that both the larger and smaller valleys of the Apen-
nines were excavated by rivers and floods, caused by
the bursting of the barriers of lakes, after the retreat
of the ocean. He also maintained that the elephants
and other quadrupeds, so frequent in the lacustrine
and alluvial deposits of Italy, had inhabited that
Peninsula; and had not been transported thither, as
Some had conceived, by Hannibal or the Romans, nor
by what they were pleased to term “a catastrophe of
Nature,” |
Lehman, 1756.—In the year 1756 the treatise of
ehman, a German mineralogist, and director of the
~'Ussian mines, appeared, who also divided mountains
mto three classes: the first, those formed with the
World, and prior to the creation of animals, and which
Contained no fragments of other rocks; the second
class, those which resulted from the partial destruc-
tion of the primary rocks by a general revolution ; and
® third class, resulting from local revolutions, and in
part. from the Noachian deluge.*
A French translation of this work appeared in 1759,
the preface of which the translator displays very
enlightened views respecting the operations of earth-
Wakes, as well as of the aqueous causes.
Gesner, 1758, — In this year Gesner, the botanist,
of Zurich, published an excellent treatise on petrifac-
tions, and the changes of the earth which they testify.+
ter a detailed enumeration of the various classes of
Ossils of the animal and vegetable kingdoms, and re-
marks on the different states in which they are found
Petrified, he considers the geological phenomena con-

* Essai d’une Hist, Nat. des Couches de Ja Terre, 1759.
T John Gesner published at Leyden, in Latin.

Currents.

in

"2 GESNER — ARDUINO. , [Book I.

nected with them; observing, that some, like those of
Giningen, resembled the testacea, fish, and plants
indigenous in the neighbouring region *; while some,
such as ammonites, gryphites, belemnites, and other
shells, are either of unknown species, or found only
in the Indian and other distant seas. In order to
elucidate the structure of the earth, he gives sections,
from Verenius, Buffon, and others, obtained in digging
wells ; distinguishes between horizontal and inclined
strata; and, in speculating on the causes of these
appearances, mentions Donati’s examination of the bed
of-the Adriatic; the filling up of lakes and seas by
sediment; the imbedding ofshells, now in progress; and
many known effects of earthquakes, such as the sink-
ing down of districts, or the heaving up of the bed of
the sea, so as to form new islands and lay dry strata
containing petrifactions. The ocean, he says, deserts
its shores in many countries, as on the borders of the
Baltic ; but the rate of recession has been so slow in
the last 2000 years, that to allow the Apennines, whose
summits are filled with marine shells, to emerge to
their present height, would have required about 80,000
years, — a lapse of time ten times greater, or more,
than the age of the universe. We must therefore refer
the phenomenon to the command of the Deity, related
by Moses, that “the waters should be gathered to-
gether in one place, and the dry land appear.” Gesner
adopted the views of Leibnitz, to account for the re-
treat of the primeval ocean : his essay displays much
erudition; and the opinions of preceding writers of
Italy, Germany, and England are commented upon
with fairness and discrimination.

Arduino, 1759.—In the year following, Arduino}, in

* Part ii. chap. 9. t Giornale del Griselini, 1759.

Ch. TIL] MICHELL. TA

his: memoirs on the mountains of Padua, Vicenza, and
Verona,

deduced, from original observations, the dis-
tinction of rocks into primary, secondary, and tertiary,
and shewed that in those districts there had been a
Succession of submarine volcanic eruptions.

Michell, 1760. — In the following year (1760) the
Rey, John Michell, Woodwardian Professor of Miner-
alogy at Cambridge, published, in the Philosophical

Fansactions, an Essay on the Cause and Phenomena
of Earthquakes.* _ His attention had been drawn to
this Subject by the great earthquake of Lisbon in 1755.

e advanced many original and philosophical views
respecting the propagation of subterranean movements,

and the caverns and fissures wherein steam might
© generated. In order to point out the application
of his theory to the structure of the globe, he was led
to describe the arrangement and disturbance of the
Strata, their usual horizontality in low countries, and
their Contortions and fractured state in the neighbour-
100d of mountain chains. He also explained, with
Surprising accuracy, the relations of the central ridges
of older rocks to the “ Jong narrow slips of similar
“arths, stones, and minerals,’ which are parallel to
these ridges. In his generalizations, derived in great
Part from his own observations on the geological
: * See a Sketch of the History of English Geology, by Dr. Fitton,
in Edinb. Rey. Feb. 1818, re-edited Lond. and Edinb. Phil. Mag.
vol. i. and ii. 1832-33. Some of Michell’s Observations antici-
Pate in so remarkable a manner the theories established forty years
afterwards, that his writings weuld probably have formed an era
in the science, if his researches had been uninterrupted. He held,

however, his professorship only eight years, when he succeeded to

= benefice, and from that time he appears to have entirely discon-
tinued his scientific pursuits.

VOL. I, E

74. CATCOTT —FORTIS — ODOARDI. [Book I.’

structure of Yorkshire, he anticipated many of the
views more fully developed by later naturalists.

Catcott, 1761. — Michell’s papers were entirely free
from all physico-theological disquisitions, but some
of his contemporaries were still earnestly engaged in
defending or impugning the Woodwardian hypothesis.
We find many of these writings referred to by Catcott,
an Hutchinsonian, who published a “Treatise on the
Deluge” in 1761. He laboured particularly to refute
an explanation offered by his contemporary, Bishop
Clayton, of the Mosaic writings. That prelate had
declared that the deluge “could not be literally true,
save in respect to that part where Noah lived before
the flood.” Catcott insisted on the universality of the
deluge, and referred to traditions of inundations men-
tioned by ancient writers, or by travellers, in the East
Indies, China, South America, and other countries.
This part of his book is valuable, although it is not
easy to see what bearing the traditions have, if admit-
ted to be authentic, on the Bishop’s argument, since
no evidence is adduced to prove that the catastrophes
were contemporaneous events, while some of them are
expressly represented by ancient authors to have oc-
curred in succession.

Fortis — Odoardi, 1761.— The doctrines of Arduino,
above adverted to, were afterwards confirmed by
Fortis and Desmarest, in their travels in the same
country; and they, as well as Baldassari, laboured to
complete the history of the Subapennine strata. In
the work of Odoardi *, there was also a clear argument
in favour of the distinct ages of the older Apennine
strata, and the Subapennine formations of more recent

* Sui Corpi Marini del Feltrino, 1761.

Ch; 11 THEORY OF RASPE. 75

origin. He pointed out that the strata of these two
Sroups were unconformable, and must have been the
deposits of different seas at distant periods of time.
Raspe, 1763. — A history of the new islands by
aspe, an Hanoverian, appeared in 1763, in Latin,.*
In this work, all the authentic accounts of earthquakes
Which had produced permanent changes on the solid
Parts of the earth were collected together and ex-
amined with judicious criticism. The best systems
Which had been proposed concerning the ancient
listory of the globe, both by ancient and modern
Writers, are reviewed; and the merits and defects
of the doctrines of Hooke, Ray, Moro, Buffon, and
Others, fairly estimated. Great admiration is expressed
for the hypothesis of Hooke, and his explanation
of the origin of the strata is shown to have been
More correct than Moro’s, while their theory of the

effects of earthquakes was the same. Raspe had not
Seen Michell’s memoir, and his views concerning the
8eological structure of the earth were perhaps less
enlarged ; yet he was able to add many additional
arguments in favour of Hooke’s theory, and to render

it, as he said, a nearer approach to what Hooke would

ve written had he lived in later times. As to the
Periods wherein all the earthquakes happened, to which
We owe the elevation of various parts of our continents
and islands, Raspe says he pretends not to assign their
duration, still less to defend Hooke’s suggestion, that
the Convulsions almost all took place during the deluge
of Noah. He adverts to the apparent indications of.

* De Novis e Mari Natis Insulis. Raspe was also the editor
Of the « Philosophical Works of Leibnitz. Amst. et Leipzig,
ASS? also author of « Tassie’s Gems,” and “ Baron Mun-
Chausen’s Travels,”

E2

l "6 ~ FUCHSEL. > [Book D

the former tropical heat of the climate of Europe; and
the changes in the species of animals and plants; as
among the most obscure and difficult problems in geo-
logy. In regard to the islands raised from the sea,
within the times of history or tradition, he declares
that some of them were composed of strata containing
organic remains, and that they were not, as Buffon
had asserted, made of mere volcanic matter. His
work concludes with -Łan eloquent exhortation to na-
turalists te examine the isles which rose, in 1707, in
the Grecian Archipelago, and, in 1720, in the Azores,
and not to neglect such splendid opportunities of stu-
dying nature “ in the act of parturition.” That Hooke’s
writings should have been neglected for more than
half a century, was matter of astonishment to Raspe;
But it is still more wonderful that his own luminous
exposition of that theory should, for more than an-
other half century, have excited so little interest.
Fuchsel, 1762 and 1773.—Fuchsel, a German phy-
sician, published, in 1762, a geological description of
the country between the Thuringerwald and the Hartz,
and a memoir on the environs of Rudelstadt*; and
afterwards, in 1773, a theoretical work on the ancient
history of the earth and of man.+ He had evidently
advanced considerably beyond his predecessor Lehman,
and was aware of the distinctness, both as to position
and fossil contents, of several groups of strata of dif-
ferent ages, corresponding to the secondary formations
now recognized by geologists in various parts of Ger-
many. He supposed the European continents to
have remained covered by the sea until the formation

* Acta Academiz Electoralis Maguntine, vol. ii. Erfurt.

+ This.account of Fuchsel is derived from an excellent analysis
of his memoirs by M. Keferstein. Journ. de Géologie, tom. ii.
Oct. F830.

Ch. 111.) * FUCHSEL — BRANDER. Ty

of the marine strata called in Germany “ muschel-
kalk,” at the same time that the terrestrial plants of
many European deposits attested the existence of dry
land which bordered the ancient sea; land which,
therefore, must have occupied the place of the present
ocean. This pre-existing continent had been gra-
dually swallowed up by the sea, different parts having
subsided in succession into subterranean caverns. AH
the sedimentary strata were originally horizontal, and
their present state of derangement must be referred to
Subsequent oscillations of the ground.

As there were plants and animals in the ancient
Periods, so also there must have been men, but they
did not all descend from one pair, but were created at
Various points on the earth’s surface; and the number
of these distinct birth-places was as great as are the
original languages of nations.

In the writings of Fuchsel we see a strong desire
Manifested to explain geological phenomena as far as
Possible by reference to the agency of known causes ;
and although some of his speculations were fanciful,

is views coincide much more nearly with those now
Senerally adopted, than the theories afterwards pro-
Mulgated by Werner and his followers.

Brander, 1766.—Gustavus Brander published, in

1766, his « Fossilia Hantoniensia,” containing excellent

Sures of fossil shells from the more modern marine
Strata of our island. “ Various opinions,” he says in
the preface, “had been entertained concerning the
time when and how these bodies became deposited.
Some there are who conceive that it might have been
effected in a wonderful length of time by a gradual
changing and shifting of the sea,” &c. But the most
Common cause assigned is that of “the deluge.” This

E 3

78 SOLDANI — FORTIS — TESTA. [Book I

conjecture, he says, even if the universality of the flood
be not called in question, is purely hypothetical. In
his opinion, fossil animals and testacea were, for the most
part, of unknown species; and of such as were known,
the living analogues now belonged to southern latitudes.

Soldani, 17780.— Soldani applied successfully his
knowledge of zoology to illustrate the history of stra-
tified masses. He explained that microscopic testacea
and zoophytes inhabited the depths of the Mediter-
ranean ; and that the fossil species were, in like manner,
found in those deposits wherein the fineness of their
particles, and the absence of pebbles, implied that they
were accumulated in a deep sea, or far from shore.
This author first remarked the alternation of marine
and fresh-water strata in the Paris basin.*

Fortis — Testa, 1793.— A lively controversy arose
between Fortis and another Italian naturalist, Testa,
concerning the fish of Monte Bolca, in 1793. Their
letters+, written with great spirit and elegance, show
that they were aware that a large proportion of the
Subapennine shells were identical with living species,
and some of them with species now living in the
torrid zone. Fortis proposed a somewhat fanciful con-
jecture, that when the volcanos of the Vicentin were
burning, the waters of the Adriatic had a higher
temperature ; and in this manner, he said, the shells
of warmer regions may once have peopled their own
seas. But Testa was disposed to think that these
species of testacea were still common to their own and
to equinoctial seas: for many, he said, once supposed
to be confined to hotter regions, had been afterwards
discovered in the Mediterranean. +

* Saggio orittografico, &c. 1780, and other Works.
+ Lett. sui Pesci Fossili di Bolca. Milan, 1793.
} This argument of Testa has been strengthened of late years

€h. WL] WHITEHURST — PALLAS — SAUSSURE. 79

. Cortesi — Spallanzani— Wallerius — Whitehurst. —
; While these Italian naturalists, together with Cortesi
and Spallanzani, were busily engaged in pointing out
the analogy between the deposits of modern and
ancient seas, and the habits and arrangement of their
Organic inhabitants, and while some progress was
Making, in the same country, in investigating the
ancient and modern volcanic rocks, some of the most
original observers among the English and German
Writers, Whitehurst * and Wallerius, were wasting
their strength in contending,. according to the old
Woodwardian hypothesis, that all the strata were
formed by the Noachian deluge. But Whitehurst’s
description of the rocks of Derbyshire was most faith-
ful; and he atoned for false theoretical views, by pro-
viding data for their refutation.

Pallas — Saussure. — Towards the close of the
eighteenth century, the idea of distinguishing the
Mineral masses on our globe into separate groups, and
Studying their relations, began to be generally diffused.
Pallas and Saussure were among the most celebrated
Whose labours contributed to this end. After an at-
tentive examination of the two great mountain chains

by the discovery, that dealers in shells had long been in the habit
a Selling Mediterranean species as shells of more southern and
distant latitudes, for the sake of enhancing their price. It ap-
pears, moreover, from several hundred experiments made by that
distinguished hydrographer, Captain Smyth, on the water witbin
eight fathoms of the surface, that the temperature of the Medi-
terranean is on an average 34° of Fahrenheit higher than the
Western part of the Atlantic ocean; an important fact, which in
Some degree may help to explain why many species are common
to tropical latitudes and to the Mediterranean. ;

if Inquiry into the Original State and Formation of the Earth.

8.

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80 PALLAS — SAUSSURE. - [Book f.

of Siberia, Pallas announced the result, that the gra-
nitic rocks were in the middle, the schistose at their
sides, and the limestones again on the outside of these;
and this he conceived would prove a general law in
the formation of all chains composed chiefly of primary
rocks.*

In his “Travels in Russia,” in 1793 and 1794, he
made many geological observations on the recent
strata near the Wolga and the Caspian, and adduced
proofs of the greater extent of the latter sea at no
distant era in the earth’s history. His memoir on the
fossil bones of Siberia attracted attention to some of
the most remarkable phenomena in geology. He

stated that he had found a rhinoceros entire in the

frozen soil, with its skin and flesh: an elephant, found
afterwards in a mass of ice on the shore of the North
sea, removed all doubt as to the accuracy of so won-
derful a discovery.+ ‘
The subjects relating to natural history which en-
gaged the attention of Pallas, were too multifarious to
admit of his devoting a large share of his labours ex-
clusively to geology. Saussure, on the other hand,
employed the chief portion of his time in studying
the structure of the Alps and Jura, and he provided
valuable data for those who followed him. He did not
pretend to deduce any general system from his nu-
merous and interesting observations ; and the few theo-
retical opinions which escaped from him, seem, like
those of Pallas, to have been chiefly derived from the
cosmological speculations of preceding writers.

* Observ. on the Formation of Mountains,

1778, parti.
+ Nov. comm. Petr. XVII. Cuvier, Eloge de Pallas.

Act. Petrop. ann.

CHAPTER IV.

HISTORY OF ‘THE PROGRESS OF GEOLOGY — continued.

Werner's Application of Geology to the Art of Mining — Excur-
sive Character of his Lectures — Enthusiasm of his Pupils ~
His Authority — His theoretical Errors—Desmarest’s Map and.
Description of Auvergne (p. 86.) — Controversy between the
Vulcanists and Neptunists — Intemperance of the rival Sects
— Hutton’s Theory of the Earth — His Discovery of Granite
Veins (p. 91.) — Originality of his Views — Why opposed —
Playfair’s Illustrations — Influence of Voltaire’s Writings on
Geology (p. 96.) — Imputations cast on the Huttonians by
Williams, Kirwan, and De Luc — Smith’s Map of England
(p. 102.) — ‘Geological Society of London — Progress of the
Science in France — Growing Importance of the Study of
Organic Remains.

Werner. — Tur art of mining has long been taught in
France, Germany, and Hungary, in scientific institu-
tions established for that purpose, where mineralogy
has always been a principal branch of instruction.*

Werner was named, in 1775, professor of that science
in the “ School of Mines,” at Freyberg, in Saxony. He
directed his attention not merely to the composition
and external characters of minerals, but also to what
he termed « geognosy,” or the natural position of

* Our miners have been left to themselves, almost without the
assistance of scientific works in the English language, and without _
any “ school of mines,” to blunder their own way into a certain
degree of practical skill. The inconvenience of this want of sys-
tem in a country where so much capital is expended, and often
wasted, in mining adventures, has been well exposed by an emi-
nent practical miner. — See “ Prospectus of a School of Mines in
Cornwall, by J. Taylor, 1825.”

ES.

Sse

ee eee
r REE FE RTE

=

a

-kindled enthusiasm in the minds of his pupils ;

82 WERNER. [Book I.

minerals in particular rocks, together with the group-
ing of those rocks, their geographical distribution, and
various relations. The phenomena observed in the
structure of the globe had hitherto served for little
else than to furnish interesting topics for philosophical
discussion: but when Werner pointed out their appli-
cation to the practical purposes of mining, they were
instantly regarded by a large class of men as an essen-
tial part of their professional education, and from that
time the science was cultivated in Europe more ar-
dently and systematically.. Werner’s mind was at once
imaginative and richly stored with miscellaneous know-
ledge. He associated every thing with his favourite
science, and in his excursive lectures he pointed out
all the economical uses of minerals, and their appli-
cation to medicine: the influence of the mineral com-

. position of rocks upon the soil, and of the soil upon

the resources, wealth, and civilization of man. The
vast sandy plains of Tartary and Africa, he would say,
retained their inhabitants in the shape of wandering
shepherds ; the granitic mountains and the low cal-
careous and alluvial plains gave rise to different
manners, degrees of wealth, and intelligence. The
history even of languages, and the migrations of tribes,
had been determined by the direction of particular
strata. The qualities of certain stones used in building
would lead him to descant on the architecture of dif-
ferent ages and nations; and the physical geography
of a country frequently invited him to treat of mil

itary
tactics. The charm of his manners and his eloq

uence

and
many, who had intended at first only to acquire a

slight knowledge of mineralogy, when they had once’
heard him, devoted themselves to it as the business of
their lives. In a few years, a small school of mines,

Ch. IV.] WERNER. 83

before unheard of in Europe, was raised to the rank
of a great university ; and men already. distinguished
m science studied the German language, and came
from the most distant countries to hear the great
oracle of geology.*

Werner had a great antipathy to the mechanical
labour of writing, and, with the exception of a valuable
treatise on metaliferous veins, he could never be per-
Suaded to pen more than a few brief memoirs, and
those containing no development of his general views.
Although the natural modesty of his disposition was
excessive, approaching even to timidity, he indulged.
in the most bold and sweeping generalizations, and he
inspired all his scholars with a most implicit faith in
his doctrines. Their admiration of his genius, and the
feelings of gratitude and friendship which they all felt
for him, were not undeserved; but the supreme au-
thority usurped by him over the opinions of his con-
temporaries was eventually prejudicial to the progress
of the science; so much so, as greatly to counter-
balance the advantages which it derived frem his
exertions. If it be true that delivery be the first,
Second, and third requisite in a popular orator, it is no
less certain that to travel is of first, second, and third
importance to those who desire to originate just and
Comprehensive views concerning the structure of our
globe. Now Werner had not travelled to distant
Countries ; he had merely explored a small portion of
Germany, and conceived, and persuaded others to
believe, that the whole surface of our planet, and all
the mountain chains in the world, were made after the
model of his own province. It became a ruling object
of ambition in the minds of his pupils to confirm the

* Cuvier, Eloge de Werner.

E 6

»

=

Sa

84 WERNER. [Book I.

` generalizations of their great master, and to discover

in the most distant parts of the globe his “ universal
formations,” which he supposed had been each in suc-
cession simultaneously precipitated over the whole
earth from a common menstruum, or “chaotic fluid.”
It now appears that the Saxon professor had misinter-
preted many of the most important appearances even
in the immediate neighbourhood of Freyberg. Thus,
for example, within a day’s journey of his school, the
porphyry, called by him primitive, has been found not
only to send forth veins or dikes through strata of the
coal formation, but to overlie them in mass. The
granite of the Hartz mountains, on the other hand,
which he supposed to be the nucleus of the chain, is
now well known to traverse and breach the other beds,
penetrating even into the plain (as near Goslar); and
still nearer Freyberg, in the Erzgebirge, the mica slate
does not mantle round the granite, as was supposed,
but abuts abruptly against it. Fragments, also, of the
greywacké slate, containing organic remains, have re-
cently been found entangled in the granite of the
Hartz, by M. de Seckendorf.*

The principal merit of Werner’s system of in-
struction consisted in steadily directing the attention
of his scholars to the constant relations of super-
position of certain mineral groups; but he had been
anticipated, as has: been shown in the last chapter, in

_the discovery of this general law, by several geologists

in Italy and elsewhere; and his leading divisions of
the secondary strata were, at the same time, and inde-
pendently, made the basis of an arrangement of the

* J am indebted for this information partly to Messrs. Sedgwick
and Murchison, who have investigated the country, and partly to
Dr. Hartmann of Blankenburg, the translator of this work into
German.

Ch. IV.) VULCANISTS AND ‘NEPTUNISTS. _ 85

British strata by our countryman, William Smith, to
whose work I shall presently return.

Controversy between the Vulcanists and Neptunists.
—In regard to basalt and other igneous rocks, Werner’s
theory was original, but it was also extremely erro-
neous. The basalts of Saxony and Hesse, to which

is observations were chiefly confined, consisted of
tabular masses capping the hills, and not connected
With the levels of existing valleys, like many in Au-
vergne and the Vivarais. These basalts, and all other
rocks of the same family in other countries, were, ac-
Cording to him, chemical precipitates from water. He
‘denied that they were the products of submarine vol-
Canos; and even taught that, in the primeval ages of
the world, there were no volcanos. His theory was
©pposed, in a twofold sense, to the doctrine of the per-
Manent agency of the same causes in nature; for not
only did he introduce, without scruple, many imaginary
Causes supposed to have once effected great revolutions
in the earth, and then to have become extinct, but
New ones also were feigned to have come into play in
Modern times; and, above all, that most violent instru-.
Ment of change, the agency of ‘subterranean fire.
So early as 1768, before Werner had commenced
is mineralogical studies, Raspe had truly charac-
terized the basalts of Hesse as of igneous origin.
Arduino, as we have already seen, had pointed out nu-
merous varieties of trap-rock in the Vicentin as ana-
logous to volcanic products, and as distinctly referable
to ancient submarine eruptions. Desmarest, as before
Stated, had, in company with Fortis, examined the
Vicentin in 1766, and confirmed Arduino’s views. In
1772, Banks, Solander, and Troil, compared the co-
lumnar basalt of Hecla with that of the Hebrides,

R6 DESMAREST’S MAP OF AUVERGNE. [Book I.

Collini, in 1774, recognized the true nature of the
igneous rocks on the Rhine, between Andernach and
Bonn. In 1775, Guettard visited the Vivarais, and
established the relation of basaltic currents to lavas.
Lastly, in 1779, Faujas published his description of
the volcanos of the Vivarais and Velay, and showed
how the streams of basalt had poured out from craters
which still remain in a perfect state.*

Desmarest.— When sound opinions had thus for
twenty years prevailed in Europe concerning the true
nature of the ancient trap-rocks, Werner by his simple
dictum caused a retrograde movement, and not only
overturned the true theory, but substituted for it one
of the most unphilosophical that can well be imagined.
The continued ascendancy of his dogmas on this sub-
ject was the more astonishing, because a variety of
new and striking facts were daily accumulated in
favour of the correct opinions previously entertained.
Desmarest, after a careful examination of Auvergne,
pointed out, first, the most recent volcanos which had
their craters still entire, and their streams of lava con-
forming to the level of the present river-courses. He
then showed that there were others of an intermediate
epoch, whose craters were nearly effaced, and whose
lavas were less intimately connected with the present
valleys; and, lastly, that there were volcanic rocks,
still more ancient, without any discernible craters or
scorie, and bearing the closest analogy to rocks in
cther parts of Europe, the igneous origin of which was
denied by the school of Freyberg. +

* Cuvier, Eloge de Desmarest.

+ Journ. de Phys. vol. xiii. p.115.; and Mém. de1’Inst.,
" Sciences Mathémat, et Phys. vol. vi. p, 219,

Ch. Iv] DOLOMIEU — MONTLOSIER, 87

Desmarest’s map of Auvergne was a work of uncom-
mon merit. He first made a trigonometrical survey
of the district, and delineated its physical geography
with minute accuracy and admirable graphic power.
He contrived, at the same time, to express, without
the aid of colours, a vast quantity of geological detail,
the different ages, and sometimes even the structure,
of the volcanic rocks, distinguishing them from the
fresh-water and the granitic. They alone who have
Carefully studied Auvergne, and traced the different
lava-streams from their craters to their termination,
—the various isolated basaltic cappings, — the rela-
tion of some lavas to the present valleys, — the ab-
‘ence of such relations in others, — can appreciate the
extraordinary fidelity of this elaborate work. No other
district, of equal dimensions in Europe exhibits, per-

aps, so beautiful and varied a series of phenomena ;
and, fortunately, Desmarest possessed at once the
Mathematical knowledge required for the construction
Of a map, skill in mineralogy, and a power of original
8€neralization. s

Dolomieu—Montlosier.— Dolomieu, another of Wer-
ner’s contemporaries, had found prismatic basalt among
the ancient lavas of Etna; and, in 1784, had observed
-`e alternations of submarine lavas and calcareous strata
'n the Val di Noto, in Sicily.* In 1790, also, he de-
Scribed similar phenomena in the Vicentin and in the
Tyrol. t Montlosier published, in 1788, an essay on

th

e theory of the volcanos of Auvergne, combining ac-
Curate local observations with comprehensive views.
otwithstanding this mass of evidence, the scholars of

* Journ. de Phys, tom. xxv. p- 191.
t Ib. tom, xxxvii, partii. p. 200.”

88 HUTTON, [Book 1.

Werner were prepared to support his opinions to their
utmost extent; maintaining, in the fulness of their
faith, that even obsidian was an aqueous precipitate.
As they were blinded by their veneration for the great
teacher, they were impatient of opposition, and soon
imbibed the spirit of a faction; and their opponents,
the Vulcanists, were not long in becoming contami-
nated with the same intemperate zeal. Ridicule and
irony were weapons more frequently employed than
argument by the rival sects, till at last the controversy
was carried on with a degree of bitterness almost un-
precedented in questions of physical science. Des-
marest alone, who had long before provided ample
materials for refuting such a theory, kept aloof from
the strife; and whenever a zealous Neptunist wished
to draw the old man into an argument, he was satisfied
with replying, “ Go and see.” *

Hutton, 1788.— It would be contrary to all analogy,
in matters of graver import, that a war should rage
with such fury on the Continent, and that the inha-
bitants of our island should not mingle in the affray.
Although in England the personal influence of Werner
was wanting to stimulate men to the defence of the
weaker side of the question, they contrived to find
good reason for espousing the Wernerian errors with
great enthusiasm. In order to explain the peculiar
motives which led many to enter, even with party feel-
ing, into this contest, it will be necessary to present
the reader with a sketch of the views unfolded by
Hutton, a contemporary of the Saxon geologist. The
former naturalist had been educated as a physician,
but, declining the practice of medicine, he resolved,

* Cuvier, Eloge de Desmarest.

Ch. IV.] HUTTONIAN THEORY. 89

when young, to remain content with the small inde-
pendence inherited from his father, and thenceforth. to
give his undivided attention to scientific pursuits. He
resided at Edinburgh, where he enjoyed the society
of many men of high attainments, who loved him for
the simplicity of his manners and the sincerity of his
‘character. His application was unwearied ; and he
made frequent tours through different parts of England
and Scotland, acquiring considerable -skill as ʻa mine-
ralogist, and constantly arriving at grand and com-
Prehensive views in geology. He communicated the
results of his observations unreservedly, and with the
fearless spirit of one who was conscious that love of
truth was the sole stimulus of his exertions. When
at length he had matured his views, he published, in
1788, his « Theory of the Earth*,” and the same,
afterwards more fully developed in a separate work, in
1795. This treatise was the first in which geology was
declared to be in no way concerned about “ questions
as to the origin of things;” the first in which an
attempt was made to dispense entirely with all hypo-
thetical causes, and to explain the former changes of
the earth’s crust by reference exclusively to natural
agents. Hutton laboured to give fixed principles to
8eclogy, as Newton had succeeded in doing to astro-
nomy: but, in the former science, too little progress
had been made towards furnishing the necessary data,
to enable any philosopher, however great his genius,
to realize so noble a project.

Huttonian theory. — “ The ruins of an older world,”
Said Hutton, \“ are visible in the present structure of
our planet; and the strata which now compose our

es Ed. Phil. ‘Trans. :1788.

00 HUTTONIAN THEORY. = [Book I.

continents have been once beneath the sea, and were
formed out of the waste of pre-existing continents.
The same forces are still destroying, by chemical de-
composition or mechanical violence, even the hardest
rocks, and transporting the materials to the sea, where
they are spread out, and form strata analogous to those
of more ancient date. ‘Although loosely deposited
along the bottom of the ocean, they become after-
wards altered and consolidated by volcanic heat, and
then heaved up, fractured, and contorted.”

Although Hutton had never explored any region of
active volcanos, he had convinced himself that basalt
and many other trap-rocks were of igneous origin, and
that many of them had been injected in a melted state
through fissures in the older strata. The compactness
of these rocks, and their different aspect from that of
ordinary lava, he attributed to their having cooled
down under the pressure of the sea; and in order to
remove the objections started against this theory, his
friend, Sir James Hall, instituted a most curious and
instructive series of chemical experiments, illustrating
the crystalline arrangement and texture assumed by
melted matter cooled under high pressure.

The absence of stratification in granite, and its ana-
logy, in mineral character, to rocks which he deemed
of igneous origin, led Hutton to conclude that granite
also must have been formed from matter in fusion ;
and this inference he felt could not be fully confirmed,
unless he discovered at the contact of granite and
other strata a repetition of the phenomena exhibited
so constantly by the trap-rocks. Resolved to try his
theory by this test, he went to the Grampians, and
surveyed the line of junction of the granite and super-
incumbent stratified masses, until he found in Glen Tilt,

Ch. TV.) HUTTONIAN THEORY. 91
in 1785, the most clear and unequivocal proofs in sup
Port of his views. Veins of red granite are there seen
branching out from the principal mass, and traversing
the black micaceous schist and primary limestone.
The intersected stratified rocks are so distinct in
colour and appearance as to render the example in
that locality most striking, and the alteration of the
limestone in contact was very analogous to that pro-
duced by trap veins on calcareous strata. This verifi-
Cation of his system filled him with delight, and called
forth such marks of joy and exultation, that the guides
who accompanied him, says his biographer, were con-
vinced that he must have discovered a vein of silver
or gold.* He was aware that the same theory would
not explain the origin of the primary schists, but
these he called primary, rejecting the term primitive,
and was disposed to consider them as sedimentary
rocks altered by heat, and that they originated in
Some other form from the waste of previously existing
rocks,

By this important discovery of granite veins, to
Which he had been led by fair induction from an inde-
Pendent class of facts, Hutton prepared the way for

e greatest innovation on the systems of his prede-
Cessors. Vallisneri had pointed out the general fact .
that there were certain fundamental rocks which con-
tained no organic remains, and which he supposed to
have been formed before the creation of living beings.

oro, Generelli, and other Italian writers, embraced
the same doctrine; and Lehman regarded the moun-
tains called by him primitive, as parts of the original
nucleus of the globe. The same tenet was an article

* Playfair's Works, vol. iv. p. 75.

92 ‘“HUTTONIAN THEORY. [Book T.

of faith in the school of Freyberg; and if any one
ventured to doubt the possibility of our being enabled
to carry back our researches to the creation of the
present order of things, the granitic rocks were tri-
umphantly appealed to. On them seemed written, in
legible characters, the memorable inscription —

Dinanzi a me non fur cose create
Se non eterne;

and no small sensation was excited when Hutton
seemed, with unhallowed hand, desirous to erase cha-
racters already regarded by many as sacred. “In
the economy of the world,” said the Scotch geologist,
“I can find no traces of a beginning, no prospect
of an end ;” a declaration the more startling when
coupled with the doctrine, that all past changes on the
globe had been brought about by the slow agency of
existing causes. The imagination was first fatigued
and overpowered by endeavouring to conceive the im-
mensity of time required for the annihilation of whole
continents by so insensible a process; and when the
thoughts had wandered through these interminable
periods, no resting place was assigned in the remotest
distance. The oldest rocks were represented to be of
a derivative nature, the last of an antecedent series,
and that, perhaps, one of many pre-existing worlds.
Such views of the immensity of past time, like those
unfolded by the Newtonian philosophy in regard to
space, were too vast to awaken ideas of sublimity un-
mixed with a painful sense of our incapacity to con-
ceive a plan of such infinite extent. ‘Worlds are seen
beyond worlds immeasurably distant from each other,
and, beyond them all, innumerable other systems are
faintly traced on the confines of the visible universe.

Ch. IV.] HUTTONIAN THEORY. 93

The characteristic feature of the Huttonian theory
was; as before hinted, the exclusion of all causes not
Supposed to belong to the present order of nature.

ut Hutton had made no step beyond Hooke, Moro,
and Raspe, in pointing out in what manner the laws
NOW governing subterranean movements might bring
about geological changes, if sufficient time be allowed:
On the contrary, he seems to have fallen far short of
Some of their views, especially when he refused to
attribute any part of the external configuration of the
farth’s crust to subsidence. He imagined that the
Continents were first gradually destroyed by aqueous

€gradation; and when their ruins had furnished ma-
terials for new continents, they were upheaved by
violent convulsions. He therefore required alternate
Periods of general disturbance and repose; and such
he believed had been, and would for ever be, the
Course of nature.

Generelli, in his exposition of Moro’s system, had
Made a far nearer approximation towards reconciling
8eological appearances with the state of nature as

nown to us; for while he agreed with Hutton, that
the decay and reproduction of rocks were always in
Progress, proceeding with the utmost uniformity, the
“arned Carmelite represented the repairs of moun-
tains by elevation from below to be effected by an
equally constant and synchronous operation. Neither
of these theories, considered singly, satisfies all the
Conditions of the great problem, which a geologist,
who rejects- cosmological causes, is called upon to
Solve; but they probably contain together the germs
of a perfect system. There can be no doubt, that
Periods of disturbance and repose have followed each
Other in succession in every region of the globe ; but it

Cor EE 5 Poe i I rt

as

94 PLAYFAIR’S ILLUSTRATIONS OF HUTTON. [Book I.

may be equally true, that the energy of the subter-
ranean movements has been always uniform as regards
the whole earth. The force of earthquakes may for a
cycle of years have been invariably confined, as it is
now, to large but determinate spaces, and may then
have gradually shifted its position, so that another
region, which had for ages been at rest, became in its
turn the grand theatre of action.

Playfair’s illustrations of Hutton.—The explanation
proposed by Hutton and by Playfair, the illustrator of
his theory, respecting the origin of valleys, and of
alluvial accumulations, was also very imperfect. They
ascribed none of the inequalities of the earth’s surface
to movements which accompanied the upheaving of
the land, imagining that valleys in general were formed
in the course of ages, by the rivers now flowing in
them; while they seem not to have reflected on the

excavating and transporting power which the waves of

the ocean might exert on land during its emergence.
Although Hutton’s knowledge of mineralogy and
chemistry was considerable, he possessed but little
information concerning organic remains ; they merely
served him, as they did Werner, to characterize certain
strata, and to prove their marine origin. The theory
of former revolutions in organic life was not yet fully
recognized ; and without this class of proofs in support
of the antiquity of the globe, the indefinite periods
demanded by the Huttonian hypothesis appeared
visionary to many ; and some, who deemed the doctrine
inconsistent with. revealed truths, indulged very un-
charitable suspicions of the motives of its author. They
accused him of a deliberate design of reviving the
heathen dogma of an “eternal succession,” and of
denying that this world ever had a beginning. Play-

Ch IV] PLAYFAIR'S ILLUSTRATIONS OF HUTTON. 95

fair, in the biography of his friend, has the following

comment on this part of their theory :—“ In the pla-
hetary motions, where geometry has carried the eye
So far, both into the future and the past, we discover
no mark either of the commencement or termination
of the present order. It is unreasonable, indeed, to
Suppose that such marks should any where exist. The
Ghar af .Natarouhasawt given laws to the universe,
Which, like the institutions of men, carry in themselves
the elements of their own destruction. He has not
Permitted in His works any symptom of infancy or of
old age, or any sign by which we may estimate either
their future or their past duration. He may put an
end, as he no doubt gave a beginning, to the present
System, at some determinate period of time; but we
May rest assured that this great catastrophe will not be

fought about by the laws now existing, and that it is
Not indicated by any thing which we perceive.” *

The party feeling excited against the Huttonian
doctrines, and the open disregard of candour and
temper in the controversy, will hardly be credited by
the reader, unless he recalls to his recollection that
the mind of the English public was at that time in a
State of feverish excitement. A class of writers in
‘rance had been labouring industriously, for many
Years, to diminish the influence of the clergy, by
Sapping the foundations of the Christian faith; and
their success, and the consequences of the Revolution,
ad alarmed the most resolute minds, while the ima-
Sination of the more timid was continually haunted by

"ead of innovation, as by the phantom of some fearful
dream.

* Playfair’s Works, vol. iv. p. 55.

96 VOLTAIRE, [Book 1I:

Voltaire. — Voltaire had used the modern discoveries
in physics as one of the numerous weapons of attack
and ridicule directed by him against the Scriptures.
He found that the most popular systems of geology
were accommodated to the sacred writings, and that
much ingenuity had been employed to make every
fact coincide exactly with the Mosaic account of the
creation and deluge. It was, therefore, with no
friendly feelings that he contemplated the cultivators
of geology in general, regarding the science as one
which had been successfully enlisted by theologians as
an ally in their cause.* He knew that the majority
of those who were aware of the abundance of fossil
shells in the interior of continents, were still persuaded
that they were proofs of the universal deluge ; and as
the readiest way of shaking this article of faith, he en-
_deavoured to inculcate scepticism as to the real nature

of such shells, and to recall from contempt the ex-
ploded dogma of the sixteenth century, that they
were sports of nature. He also pretended that vege-
table impressions were not those of real plants.+ Yet
he was perfectly convinced that the shells had really
belonged to living testacea, as may be seen in his

* In allusion to the theories of Burnet, Woodw zard, and other

pliysico-theological writers, he declared that they were as fond of

changes of scene on the face of the globe, as were the populace at

a play. ‘ Every one of them destroys and renovates the earth

after his own fashion, as Descartes framed it: for philosophers

put themselves without ceremony in the place of God, and think
to create a universe with a word.” — Dissertation envoyée a |’ Aca-
démie de Boulogne, sur les Changemens arrivés dans notre Globe-
- Unfortunately, this and similar ridicule directed against the cos-
mogonists was too well deserved.
+ See the chapter on “ Des Pierres figurés,”

)

Ch. IV] VOLTAIRE. 97

essay “On the formation of Mountains.” * He would
Sometimes, in defiance of all consistency, shift his
round when addressing the vulgar ; and, admitting
the true nature of the shells collected in the Alps
and other places, pretend that they were Eastern
Species, which had fallen from the hats of pilgrims
Coming from Syria. The numerous essays written by

im on geological subjects were all calculated to
Strengthen prejudices, partly because he was ignorant
of the real state of the science, and partly from his
bad faith.+ On the other hand, they who knew that

is attacks were directed by adesire to invalidate
Scripture, and who were unacquainted with the true
Merits of the question, might well deem the old di-
luvian hypothesis incontrovertible, if Voltaire could
adduce no-better argument against it than to deny the
true nature of organic remains.

It is only by careful attention to impediments
originating in extrinsic causes, that we can explain the ©
Slow and reluctant adoption of the simplest truths in
Seology. First, we find many able naturalists ad-
ducing the fossil remains of marine animals as proofs
of an event related in Scripture. The evidence is

* In that essay he lays it down, “ that all naturalists are now
agreed that deposits of shells in the midst of the continents are
Monuments of the continued occupation of these districts by the
Ocean,” In another place also, when speaking of the fossil shells
of Touraine, he admits'their true origin.

t As an instance of his desire to throw doubt indiscriminately on

all geological data, we may recall the passage where he says, that

ni the bones of a rein-deer and hippopotamus discovered near

Etampes did not prove, as some would have it, that Lapland and

the Nile were once on a tour from Paris to Orleans, but merely

that a lover of curiosities once preserved them in his cabinet.”
VOL. I. F

98 SPIRIT OF INTOLERANCE. 3 [Book 1.

deemed conclusive by the multitude for a century or
more ; for it favours opinions which they entertained
‘before, and they are gratified by supposing them con-
firmed by fresh and unexpected proofs. Many, who
see through the fallacy, have no wish to undeceive
those who are influenced by it, approving the effect of
the delusion, and conniving at it as a pious fraud;
until, finally, an opposite party, who are hostile to the
sacred writings, labour to explode the erroneous opi-
nion, by substituting for it another dogma which they
know to be equally unsound.

The heretical Vulcanists were soon after openly as-
sailed in England, by imputations of the most illiberal
kind. We cannot estimate the malevolence of such
a persecution, by the pain which similar insinuations
might now inflict: for although charges of infidelity
and atheism must always be odious, they were injurious
in the extreme at that moment of political excitement ;
and it was better, perhaps, for a man’s good reception
in society, that his moral character should have been
traduced, than that he should become a mark for these
poisoned weapons.

I shall pass over the works of numerous divines, who
may be excused for sensitiveness on points which then
excited so much uneasiness in the public mind; and
shall say nothing of the amiable poet Cowper*, who
could hardly be expected to have inquired into the
merit of doctrines in physics. But in the foremost
ranks of the intolerant, are found several laymen who
had high claims to scientific reputation. Among these
appears Williams, a mineral surveyor of Edinburgh,
who published a “Natural History of the Mineral

* The Task, book iii. “ The Garden.”

a ane a EE R a

th Iv] - FERN Aone ETT: 99

Kingdom,” in 1789; a work of great merit for that
day, and of practical utility, as containing the best
account of the coal strata. In his preface he misre-
Presents Hutton’s theory altogether, and charges him
with considering all rocks to be lavas of different
Colours and structure; and also with « warping every
thing to support the eternity of the world.”* He
€scants on the pernicious influence of such sceptical
Notions, as leading to downright infidelity and atheism,
“and as being nothing less than to depose the
Almighty Creator of the universe from his office.” +

Kirwan — De Luc.— Kirwan, president of the Royal
Academy of Dublin, a chemist and mineralogist of
Some merit, but who possessed much greater authority
in the scientific world than he was entitled by his
talents to enjoy, said, in the introduction to his “ Geo-
logical Essays, 1799,” “that sound geology graduated
into religion, and was required to dispel certain
Systems of atheism or infidelity, of which they had
had recent experience.” { He was an uncompromising
defender of the aqueous theory of all rocks, and was
Scarcely surpassed by Burnet and Whiston, in his
desire to adduce the Mosaic writings in confirmation
of his opinions.

De Luc, in the preliminary discourse to his Treatise
on Geology §, says, “the weapons have been changed
by which revealed religion is attacked; it is now
assailed by geology, and the knowledge of this science
has become essential to theologians.” He imputes the
failure of former geological systems to their having
been anti-Mosaical, and directed against a “ sublime
tradition.” These and similar imputations, reiterated

* P. 577. + P. 59.
¢ Introd. p. 2. § London, 1809.
` F 2

100 SPIRIT OF INTOLERANCE. [Book I.

in the works of De Luc, seem to have been taken for
granted by some modern writers: it is therefore
necessary to state, in justice to the numerous geo-
logists of different nations, whose works have been
considered, that none of them were guilty of endea-
vouring, by arguments drawn from physics, to in-
validate scriptural tenets. On the contrary, the
majority of them who were fortunate enough “ to
discover the true causes of things,” rarely deserved
another part of the poet’s panegyric, “Atque metus
omnes subjecit pedibus.” ‘The caution, and even timid
reserve, of many eminent Italian authors of the earlier
period is very apparent: and there can hardly be a
doubt, that they subscribed to certain dogmas, and
particularly to the first diluvian theory, out of de-
ference to popular prejudices, rather than from
conviction. If they were guilty of dissimulation, we
may feel regret, but must not blame their want of
moral courage, reserving rather our condemnation for
the intolerance of the times, and that inquisitorial
power which forced Galileo to abjure, and the two
Jesuits to disclaim the theory of Newton.*

* Ina most able article, by Mr. Drinkwater, on the “ Life of
Galileo,” published in the “ Library of Useful Knowledge,” it is
stated that both Galileo’s work, and the book of Copernicus “ Nisi
corrigatur” (for, with the omission of certain passages, it was sanc-
tioned), were still to be seen on the forbidden list of the Index
at Rome in 1828. I was however assured in the same year, by
Professor Scarpellini, at Rome, that Pius VIL., a Pontiff distin-
guished for his love of science, had procured a repeal of the edicts
against Galileo and the Copernican system. He had assembled
the Congregation ; and the late Cardinal Toriozzi, assessor of the
Sacred Office, proposed “ that they should wipe off this scandal
from the church. The repeal was carried, with the dissentient
voice of one Dominican only. Long before that time the New-

Ch: Iv.j PLAYFAIR’S DEFENCE OF HUTTON. 101

Hutton answered Kirwan’s attacks with great
warmth, and with the indignation justly excited by
unmerited reproach. “He had always displayed,”
Says Playfair, “the utmost disposition to admire the
beneficent design manifested in the structure of the
world; and he contemplated with delight those parts
of his theory which made the greatest additions to our
knowledge of final causes.” We may say with equal
truth, that in no scientific works in our language can
More eloquent passages be found, concerning the fit-
ness, harmony, and grandeur of all parts of the creation,
than in those of Playfair. They are evidently the un-
affected expressions of a mind, which contemplated
the study of nature, as best calculated to elevate our
Conceptions of the attributes of the First Cause. At
any other time the force and elegance of Playfair’s
Style must have insured popularity to the Huttonian
doctrines; but, by a singular coincidence, Neptuni-
anism and orthodoxy were now associated in the same
Creed; and the tide of prejudice ran so strong, that
the majority were carried far away into the chaotic
fluid, and other cosmological inventions of Werner.
These fictions the Saxon professor had borrowed with
little modification, and without any improvement, from
his predecessors. They had not the smallest foun-
dation either in Scripture or in common sense, and
were probably approved of by many as being so ideal
and unsubstantial, that they could never come into-
Violent collision with any preconceived opinions.

tonian theory had been taught in the Sapienza, and all Catholic
Universities in Europe (with the exception, I am told, of Sala-
manca); but it was always required of professors, in deference to
the decrees of the church, to use the term hypothesis, instead of
theory « They now speak of the Copernican theory. -

F 3

102 SMITH’S MAP OF ENGLAND. [Book I.

According to De Luc, the first essential distinction
to be made between the various phenomena exhibited
on the surface of the earth was, to determine which
were the results of causes still in action, and which had
been produced by causes that had ceased to act. The
form and composition of the mass of our continents,
he said, and their existence above the level of the sea,
must be ascribed to causes no longer in action. These
continents emerged, at no very remote period, on the
sudden retreat of the ocean, the waters of which made
their way into subterranean caverns. The formation
of the rocks which enter into the crust of the earth
began with the precipitation of granite from a pri-
mordial liquid, after which other strata containing the
remains of organized bodies were deposited, till at last
the present sea remained as the residuum of the pri-
mordial liquid, and no longer continued to produce
mineral strata.*

William Smith, 1790.— While the tenets of the
rival schools of Freyberg and Edinburgh were warmly
espoused by devoted partisans, the labours of an indi-
vidual, unassisted by the advantages of wealth or
station in society, were almost unheeded. Mr. William
Smith, an English surveyor, published his “Tabular
View of the British Strata” in 1790, wherein he pro-
posed a classification of the secondary formations in
the West of England. Although he had not commu-
nicated with Werner, it appeared by this work that he
had arrived at the same views respecting the laws of
superposition of stratified rocks; that he was aware
that the order of succession of different groups was

* Elementary Treatise on Geology. London, 1809. Trans-
lated by De la Fite.

Ch. IV.] SMITH’S MAP OF ENGLAND. 103

never inverted; and that they might be identified at
very distant points by their peculiar organized fossils.

From the time of the appearance of the “ Tabular
View,” the author laboured to construct a geological
map of the whole of England; and, with the greatest
disinterestedness of mind, communicated the results of
his investigations to all who desired information, giving
such publicity to his original views, as to enable his
contemporaries almost to compete with him in the
race. The execution of his map was completed in
1815, and remains a lasting monument of original
talent and extraordinary perseverance; for he had
explored the whole country on foot without the guid-
ance of previous observers, or the aid of fellow-
labourers, and had succeeded in throwing into natural
divisions the whole complicated series of British rocks.
D’Aubuisson, a distinguished pupil of Werner, paid a
just tribute of praise to this remarkable performance,
observing, that “what many celebrated mineralogists
had only accomplished for a small part of Germany in
the course of half a century, had been effected by a
single individual for the whole of England.” *

Werner invented a new language to express his
divisions of rocks, and some of his technical terms,
Such as grauwacke, gneiss, and others, passed current
M every country in Europe. Smith adopted for the
Most part English provincial terms, often of barbarous
Sound, such as gault, cornbrash, clunch clay; and
affixed them to subdivisions of the British series.

any of these still retain their place in our scientific
Classifications, and attest his priority of arrangement.

* See Dr. Fitton’s Memoir, before cited, p. 57.

F4

GEOLOGICAL SOCIETY OF LONDON. [Book L

MODERN PROGRESS OF GEOLOGY.

The contention ‘of the rival factions of the Vulcan-
ists and Neptunists had been carried to such a height,
that these names had become terms of reproach ; and
the two parties had been less occupied in searching
for truth, than for such arguments as might strengthen
their own cause, or serve to annoy their antagonists.
A new school at last arose, who professed the strictest
neutrality, and the utmost indifference to the systems
of Werner and Hutton, and who resolved diligently to
devote their labours to observation. The reaction,
provoked by the intemperance of the conflicting -
parties, now produced a tendency to extreme caution.
Speculative views were discountenanced, and, through
fear of exposing themselves to the suspicion of a bias
towards the dogmas of a party, some geologists became
anxious to entertain no opinion whatever on the causes
of phenomena, and were inclined to scepticism even
where the conclusions deducible from observed facts
scarcely admitted of reasonable doubt.

Geological Society of London.— But although the
reluctance to theorize was carried somewhat to excess,
no measure could be more salutary at such a moment
than a suspension of all attempts to form what were
termed ‘theories of the earth.” A great body of new
data were required; and the Geological Society of
London, founded in 1807, conduced greatly to the at-
tainment of this desirable end. To multiply and record
observations, and patiently to await the result at some
future period, was the object proposed by them; and
it was their favourite maxim that the time was not yet
come for a general system of geology, but that all
must be content for many years to be exclusively en-

Ch, IV] STUDY OF ORGANIC REMAINS. 105

gaged in furnishing materials for future generalizations.
By acting up to these principles with consistency, they
in a few years disarmed all prejudice, and rescued the
Science from the imputation of being a dangerous, or
at best but a visionary pursuit.

A distinguished modern writer has with truth re-
marked, that the advancement of three of the main
divisions of geological inquiry have, during the last
half century, been promoted successively by three dif-
ferent nations of Europe,—the Germans, the English,
and the French.* We have seen that the systematic
study of what may be called mineralogical geology had
its origin, and chief point of activity, in Germany,
where Werner first described with precision the
Mineral characters of rocks. The classification of the
Secondary formations, each marked by their peculiar
fossils, belongs, in a great measure, to England, where
the labours before alluded to of Smith, and those of
the most active members of the Geological Society of
London, were steadily directed to these objects. The
foundation of the third branch, that relating to the
tertiary formations, was laid in France by the splendid
work of Cuvier and Brongniart, published in 1808,
“On the Mineral Geography and Organic Remains of —
the Neighbourhood of Paris.”

We may still trace, in the language of the science
and our present- methods of arrangement, the various
Countries where the growth of these several depart-
ments of geology was at different times promoted.
Many names of simple minerals and rocks remain to
this day German; while the European divisions of the
secondary strata are in great’part English, and are, in-

* Whewell, British Critic, No, xvii. p. 187. 1831.
Fo

106 STUDY OF ORGANIC REMAINS, ' [Book I.

deed, often founded too exclusively on English types.
Lastly, the subdivisions first established of the succes-
sion of strata in the Paris basin have served as normal
groups, to which other tertiary deposits throughout
Europe have been compared, even in cases where this
standard, as will afterwards be shewn, was wholly
inapplicable.*

No period could have been more fortunate for the
discovery, in the immediate neighbourhood of Paris, of
a rich store of well-preserved fossils, than the com-
mencement of the present century; for at no former
era had Natural History been cultivated with such
enthusiasm in the French metropolis. The labours of
Cuvier in comparative osteology, and of Lamarck in
recent and fossil shells, had raised these departments
of study to a rank of which they had never previously
been deemed susceptible. Their investigations had
eventually a powerful effect in dispelling the illusion
which had long prevailed concerning the absence of
analogy between the ancient and modern state of our
planet. A close comparison of the recent and fossil
species, and the inferences drawn in regard to their
habits, accustomed the geologist to contemplate the
earth as having been at successive periods the dwelling-
place of animals and plants of different races, some
terrestrial, and others aquatic— some fitted to live in
seas, others in the waters of lakes and rivers. By the
consideration of these topics, the mind was slowly
and insensibly withdrawn from imaginary pictures of
catastrophes and chaotic confusion, such as haunted
the imagination of the early cosmogonists. Numerous
proofs were discovered of the tranquil deposition of

* Book iv. chap. ii.

Ch. IV.] MODERN PROGRESS OF GEOLOGY. - 107

Sedimentary matter, and the slow development of
organic life. If many writers, and Cuvier himself in
the number, still continued to maintain, that “the
thread of induction was broken*,” yet, in reasoning
by the strict rules of induction from recent to fossil
Species, they in a great measure disclaimed the dogma
Which in theory they professed. The adoption of the
Same generic, and, in some cases, even of the same
Specific, names for the exuvie of, fossil animals and
their living analogues, was an important step towards
familiarizing the mind with the idea of the identity
and unity of the system in distant eras. It was an
acknowledgment, as it were; that part at least of the
ancient memorials of nature were written in a living
language. The growing importance, then, of the
Natural history of organic remains may be pointed out
as the characteristic feature of the progress of the
Science during the present century. This branch of
knowledge has already become an instrument of great
utility in geological classification, and is continuing
daily to unfold new data for grand and enlarged views
respecting the former changes of the earth.

When we compare the result of observations in the
last thirty years with those of the three preceding cen-
turies, we cannot but look forward with the most san-
guine expectations to the degree of excellence to which
geology may be carried, even by the labours of the
Present generation. Never, perhaps, did any science,
with the exception of astronomy, unfold, in an equally
brief period, so many novel and unexpected truths, and

Overturn so many preconceived opinions. The senses
had for ages declared the earth to be at rest, until the

* Discours sur les Révol. &c.

F6

108 MODERN PROGRESS OF GEOLOGY. © [Book L

astronomer taught that it was carried through space
with inconceivable rapidity. In like manner was the
surface of this planet regarded as having remained
unaltered since its creation, until the geologist proved
that it had been the theatre of reiterated change, and
was still the subject of slow but never-ending fluctu-
ations. The discovery of other systems in the bound-
less regions of space was the triumph of astronomy :
to trace the same system through various transform-
ations—to behold it at successive eras adorned with
different hills and valleys, lakes and seas, and peopled
with new inhabitants, was the delightful meed of geo-
logical research. By the geometer were measured the
regions of space, and the relative distances of the
heavenly bodies ;—by the geologist myriads of ages
were reckoned, not by arithmetical computation, but
by a train of physical events—a succession of pheno-
mena in the animate and inanimate worlds—signs
which convey to our minds more definite ideas than
figures can do of the immensity of time.

Whether our investigation of the earth’s history and
structure will eventually be productive of as great
practical benefits to mankind as a knowledge of the
distant heavens, must remain for the decision of pos-
terity. It was not till astronomy had been enriched
by the observations of many centuries, and had made
its way against popular prejudices to the establisment
of a sound theory, that its application to the useful
arts was most conspicuous. The cultivation of geology
began at a later period; and in every step which it has
hitherto made towards sound theoretical principles, it
has had to contend against more violent prepossessions.
The practical advantages already derived from it have
not been inconsiderable: but our generalizations are

Ch. IV] MODERN PROGRESS OF GEOLOGY. _ 109

yet imperfect, and they who come after us may be
expected to reap the most valuable fruits of our labour.
Meanwhile the charm of first discovery is our own ;
and, as we explore this magnificent field of inquiry,
the sentiment of a great historian of our times may
continually be present to our minds, that “he who
calls what has vanished back again into being, enjoys
a bliss like that of creating.” *

* Niebuhr’s Hist. of Rome, vol. i. p. 5. Hare and Thirlwall’s
translation.

CHAPTER V.

CAUSES WHICH HAVE RETARDED THE PROGRESS OF
GEOLOGY.

Effects of prepossessions in regard to the duration of past time —
Of prejudices arising from our peculiar position as inhabitants
of the land (p. 121.) — Of those occasioned by our not seeing
subterranean changes now in progress — All these causes com-
bine to make the former course of Nature appear different from
the present — Several objections to the assumption, that existing
causes have produced the former changes of the earth’s surface,

removed by modern discoveries (p. 125.).

Ir we reflect on the history of the progress of geology,
as explained in the preceding chapters, we perceive
that there have been great fluctuations of opinion
respecting the nature of the causes to which all
former changes of the earth’s surface are referable.
The first observers conceived the monuments which
the geologist endeavours to decipher to relate to an
original state of the earth, or to a period when there
were causes in activity, distinct, in kind and degree,
from those now -constituting the economy of nature.
These views were gradually modified, and some of
them entirely abandoned in proportion as observations
were multiplied, and the signs of former mutations
more skilfully interpreted. Many appearances, which
had for a long time been regarded as indicating mys-
terious and extraordinary agency, were finally recog-
nized as the necessary result of the laws now governing

Ch. V.J PROGRESS OF GEOLOGY. 111

the material world; and the discovery of this unlooked-
for conformity has at length induced some philoso-
phers to infer, that, during the ages contemplated in
geology, there has never been any interruption to the
agency of the same uniform laws of change. The
Same assemblage of general causes, they conceive,
may have been sufficient to produce, by their various
Combinations, the endless diversity of effects, of which
the shell of the earth has preserved the memorials ; -
and, consistently with these principles, the recurrence
of analogous changes is expected by them in time to
Come,

Whether we coincide or not in this doctrine, we must
admit that the gradual progress of opinion concerning
the succession of phenomena in very remote eras, re-
Sembles, in a singular manner, that which has accom-
Panied the growing intelligence of every people, in
regard to the economy of nature in their own times.
In an early stage of advancement, when a great num-
ber of natural appearances are unintelligible, an eclipse,
an earthquake, a flood, or the approach of a comet,
With many other occurrences afterwards found to be-
long to the regular course of events, are regarded as
prodigies. The same delusion prevails as to moral
Phenomena, and many of these are ascribed to the in-
tervention of demons, ghosts, witches, and other im-
Material and supernatural agents. By degrees, many
of the enigmas of the moral and physical world are
explained, and, instead of being due to extrinsic and —
irregular causes, they are found to depend on fixed
and invariable laws. The philosopher at last becomes
Convinced of the undeviating uniformity of secondary
causes; and, guided by his faith in this principle, he
determines the probability of accounts transmitted to

112 PREJUDICES WHICH RETARD ; [Book L

him of former occurrences, and often rejects the
fabulous tales of former times, on the ground of their
being irreconcilable with the experience of more en-
lightened ages.

Prepossessions in regard to the duration of past
tume.— As a belief in the want of conformity in the
causes by which the earth’s crust has been modified
in ancient and modern periods was, for a long time,
universally prevalent, and that, too, amongst men who
have been convinced that the order of nature is now
uniform, and that it has continued so for several
thousand years, every circumstance which could have
influenced their minds and given an undue bias to their
opinions deserves particular attention. Now the reader
may easily satisfy himself, that, however undeviating
the course of nature may have been from the earliest
epochs, it was impossible for the first cultivators of
geology to come to such a conclusion, so long as they
were under a delusion as to the age of the world, and
the date of the first creation of animate beings. How-
ever fantastical some theories of the sixteenth century
may now appear to us,—however unworthy of men
of great talent and sound judgment, — we may rest
assured that, if the same misconception now prevailed
in regard to the memorials of human transactions, it
would give rise to a similar train of absurdities. Let
us imagine, for example, that Champollion, and the
French and Tuscan literati lately engaged in exploring
the antiquities of Egypt, had visited that country with
a firm belief that the banks of the Nile were never
peopled by the human race before the beginning of
the nineteenth century, and that their faith in this
dogma was as difficult to shake as the opinion of our
ancestors, that the earth was never the abode of living

we

Ch, V.] ' THE PROGRESS OF GEOLOGY. 113
beings until the creation of the present continents,
and of the species now existing, —it is easy to perceive
what extravagant systems they would frame, while
under the influence of this delusion, to account for the
Monuments discovered in Egypt. The sight of the py-
ramids, obelisks, colossal statues, and ruined temples,
Would fill them with such astonishment, that for a
time they would be as men spell-bound — wholly in-
Capable of reasoning with sobriety. They might incline
at first to refer the construction of such stupendous
Works to some superhuman powers of a primeval world.
A System might be invented resembling that so gravely
advanced by Manetho, who relates that a dynasty of
gods originally ruled in Egypt, of whom Vulcan, the
first monarch, reigned nine thousand years; after
whom came Hercules and other demigods, who were
at last succeeded by human kings.

When some fanciful speculations of this kind had
amused their imaginations for a time, some vast repo-
Sitory of mummies would be discovered, and would
M™mediately undeceive those antiquaries who enjoyed
an opportunity of personally examining them; but, the
Prejudices of others at a distance, who were not eye-
Witnesses of the whole phenomena, would not be so
easily overcome. The concurrent report of many tra-
Vellers would, indeed, render it necessary for them to
accommodate ancient theories to some of the new
facts, and much wit and ingenuity would be required
to modify and defend their old positions. Each new
Mvention would violate a greater number of known
analogies; for if a theory be required to embrace some
false principle, it becomes more visionary in proportion
as facts are multiplied, as would be the case if geo-
Meters were now required to form an astronomical

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114 PREJUDICES WHICH RETARD [Book L

system on the assumption of the immobility of the
earth.

Amongst other fanciful conjectures concerning the
history of Egypt, we may suppose some of the follow-
ing to be started. “ As the banks of the Nile have
been so recently colonized for the first time, the
curious substances called mummies could never in
reality have belonged to men. They may have been
generated by some plastic virtue residing in the interior
of the earth, or they may: be abortions of nature pro-
duced by her incipient efforts in the work of creation.
For if deformed beings are sometimes born even now,
when the scheme of the universe is fully developed,
many more may have been ‘sent before their time,
scarce half made up,’ when the planet itself was in the
embryo state. But if these notions appear to derogate
from the perfection of the Divine attributes, and if
these mummies be in all their parts true represent-
ations of the human form, may we not refer them to
the future rather than the past? May we not be
looking into the womb of Nature, and not her grave ?
May not these images be like the shades of the unborn
in Virgils Elysium—the archetypes of men not yet
called into existence?”

These speculations, if advocated by eloquent writers,
would not fail to attract many zealous votaries, for
they would relieve men from the painful necessity of
renouncing preconceived opinions. Incredible as such
scepticism may appear, it has been rivalled by many
systems of the sixteenth and seventeenth centuries,
and among others by that of the learned Falloppio, who
regarded the tusks of fossil elephants as earthy con- —
cretions, and the pottery or fragments of vases in the
Monte Testaceo, near Rome, as works of nature, and

Ch. V.] THE PROGRESS OF GEOLOGY. 115

not of art. But when one generation had passed
away, and another, not compromised to the support of
antiquated dogmas, had succeeded, they would review
the evidence afforded by mummies more impartially,
and would no longer controvert the preliminary ques-
tion, that human beings had lived in Egypt before the
Nineteenth century: so that when a hundred years
Perhaps had been lost, the industry and talents of the
Philosopher would be at last directed tothe elucidation
of points of real historical importance.

But the above arguments are aimed against one
only of many prejudices with which the earlier geolo-
gists had to contend. Even when they conceded that
the earth had been peopled with animate beings at an
earlier period than was at first supposed, they had no
Conception that the quantity of time bore so great a
Proportion to the historical era as is now generally
conceded. How fatal every error as to the quantity
of time must. prove to the introduction of rational
Views concerning the state of things in former ages,
may be conceived by supposing the annals of the civil
and military transactions of a great nation to be
Perused under the impression that they occurred in
@ period of one hundred instead of two thousand
years. Such a portion of history would immediately
assume the air of a romance; the events would seem
devoid of credibility, and inconsistent with the present
Course of human affairs. A crowd of incidents would
follow each other in thick succession. Armies and
fleets would appear to be assembled only to be de-
Stroyed, and cities built merely to fall in ruins.
There would be the most violent transitions from
foreign or intestine war to periods of profound peace,
and the works effected during the years of disorder or

Lae S

Fe ee a eee

116 PREJUDICES WHICH RETARD [Book 1.

tranquillity would appear alike superhuman in mag-
nitude.

He who should study the monuments of the natural
world under the influence of a similar infatuation,
must draw a no less exaggerated picture of the energy
and violence of causes, and must experience the same
insurmountable difficulty in reconciling the former
and present state of nature. If we could behold in
one view all the volcanic cones thrown up in Iceland,
Italy, Sicily, and other parts of Europe, during the
last five thousand years, and could see the lavas which
have flowed during the same period; the dislocations,
subsidences, and elevations caused by earthquakes;
the lands added to various deltas, or devoured by the
sea, together with the effects of devastation by floods,
and imagine that all these events had happened in one
year, we must form most exalted ideas of the activity
of the agents, and the suddenness of the revolutions.
Were an equal amount of change to pass before our
eyes in the next year, could we avoid the conclusion
that some great crisis of nature was at hand? If
geologists, therefore, have misinterpreted the signs of
a succession of events, so as to conclude that centuries
were implied where the characters imported thousands
of years, and thousands of years where the language of
nature signified millions, they could not, if they rea-
soned logically from such false Premises, come to any
other conclusion than that the system of the natural
world had undergone a complete revolution.

We should be warranted in ascribing the erection of
the great pyramid to superhuman power, if we were
convinced that it was raised in one day ; and if we
imagine, in the same manner, a mountain-chain to
have been elevated, during an equally small fraction

Ch. V.] THE PROGRESS OF GEOLOGY. 117

of the time which was really occupied in upheaving it,
we might then be justified in inferring, that the sub-
terranean movements were once far more energetic
than in our own times. We know that one earthquake
May raise the coast of Chili for a hundred miles to the
average height of about three feet. A repetition of two
thousand shocks, of equal violence, might produce a
Mountain-chain one hundred miles long, and six thou-
sand feet high. Now, should one or two only of these
Convulsions happen in a century, it would be consistent
With the order of events experienced by the Chilians
from the earliest times; but if the whole of them were
to occur in the next hundred years, the entire district
Must be depopulated, scarcely any animals or plants
Could survive, and the surface would be one confused
heap of ruin and desolation.

One consequence of undervaluing greatly the quan-
tity of past time, is the apparent coincidence which it
Occasions of events necessarily disconnected, or which
are so unusual, that it would be inconsistent with all
Calculation of chances to suppose them to happen at
One and the same time. When the unlooked-for asso-
Clation of such rare phenomena is witnessed in the
Present course of nature, it scarcely ever fails to excite
à Suspicion of the preternatural in those minds which
are not firmly convinced of the uniform agency. of
Secondary causes ;—as if the death of some individual
m whose fate they are interested happens to be ac-
companied by the appearance of a luminous meteor,
or a comet, or the shock of an earthquake. It would

e only necessary to multiply such coincidences in-
definitely, and the mind of every philosopher would be
disturbed. Now it would be difficult to exaggerate
the number of physical events, many of them most

118 PREJUDICES WHICH RETARD [Book I.

rare and unconnected in their nature, which were
imagined by the Woodwardian hyphothesis to have hap-
pened in the course of a few months: and numerous
other examples might be found of popular geological
theories, which require us to imagine that a long suc-
cession of events happened in a brief and almost mo-
. mentary period.

Another liability to error, very nearly allied to the
former, arises from the frequent contact of geological
monuments referring to very distant periods of time.
_ We often behold, at one glance, the effects of causes
which have acted at times incalculably remote, and
yet there may be no striking circumstances to mark
the occurrence of a great chasm in the chronological
series of Nature’s archives. In the vast interval of
time which may really have elapsed between the
results of operations thus compared, the physical con-
dition of the earth may, by slow and insensible modi-
fications, have become entirely altered; one or more
races of organic beings may have passed away, and
yet have left behind, in the particular region under
contemplation, no trace of their existence.

' To a mind unconscious of these intermediate events,
the passage from one state of things to another must
appear so violent, that the idea of revolutions in the
system inevitably suggests itself. The imagination is
as much perplexed by the deception, as it might be if
two distant points in space were suddenly brought into
immediate proximity. Let us suppose, for a moment,
that a philosopher should lie down to sleep in some
arctic wilderness, and then be transferred by a power,
such as we read of in tales of enchantment, to a valley
in a tropical country, where, on awaking, he might
find himself surrounded by birds of brilliant plumage,

Ch. v] THE PROGRESS OF GEOLOGY. 119
and all the luxuriance of animal and vegetable forms
of which Nature is so prodigal in those regions. The
most reasonable supposition, perhaps, which he could
make, if by the necromancer’s art he was placed in
Such a situation, would be, that he was dreaming;
and ifa geologist form theories under a similar delu-
Sion, we cannot expect him to preserve more con-
sistency in his speculations, than in the train of ideas
m an ordinary dream.

It may afford, perhaps, a more lively illustration of
the principle here insisted upon, if I recall to the
Teader’s recollection the legend of the Seven Sleepers.

he scene of that popular fable was placed in the two
Centuries which elapsed between the reign of the
emperor Decius and the death of Theodosius the
Younger. In that interval of time (between the years
249 and 450 of our era) the union of the Roman
“mpire had been dissolved, and some of its fairest pro-
vinces overrun by.the barbarians of the north. The
Seat of government had passed from Rome to Con-
Stantinople, and the throne from a Pagan persecutor
to a succession of Christian and orthodox princes.

he genius of the empire had been humbled in the
ust, and the altars of Diana and Hercules were on
the point of being transferred to Catholic saints and
Martyrs. The legend relates “ that when Decius was
still persecuting the Christians, seven noble youths of
phesus concealed themselves in a spacious cavern in
the side of an adjacent mountain, where they were
doomed to perish by the tyrant, who gave orders that
the entrance should be firmly secured with a pile
of huge stones. They immediately fell into a deep
slumber, which was miraculously prolonged, without
injuring the powers of life, during a period of 187 years.

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120 PREJUDICES WHICH RETARD [Book I.

At the end of that time the slaves of Adolius, to whom
the inheritance of the mountain had descended, re-
moved the stones to supply materials for some rustic
edifice : the light of the sun darted into the cavern, and
the seven sleepers were permitted to awake. After a
slumber, as they thought, of a few hours, they were
pressed by the calls of hunger, and resolved that
Jamblichus, one of their number, should secretly
return to the city to purchase bread for the use of his
companions. The youth could no longer recognize
the once familiar aspect of his native country, and his
surprise was increased by the appearance of a large
cross triumphantly erected over the principal gate of
Ephesus. His singular dress and obsolete language
confounded the baker, to whom he offered an ancient
medal of Decius as the current coin of the empire ;
and Jamblichus, on the suspicion of a secret treasure,
was dragged before the judge. Their mutual inquiries
produced the amazing discovery, that two centuries
were almost elapsed since Jamblichus and his friends
had escaped from the rage of a Pagan tyrant.”*

This legend was received as authentic throughout
the Christian world before the end of the sixth century;
and was afterwards introduced by Mahomet as a divine
revelation into the Koran, and from hence was adopted
and adorned by all the nations from Bengal to Africa
who professed the Mahometan faith. Some vestiges
even of a similar tradition have been discovered in
Scandinavia. “This easy and universal belief,” ob-
serves the philosophical historian of the Decline and
Fall, “ so expressive of the sense of mankind, may be
ascribed to the genuine merit of the fable itself. We

* Gibbon, Decline and Fall, chap. xxiii.

Ch, V.] THE PROGRESS OF GEOLOGY. 121

imperceptibly advance from youth to age, without ob-
Serving the gradual, but incessant, change of human
affairs; and even in our larger experience of history,
the imagination is accustomed, by a perpetual series of
Causes and effects, to unite the most distant revolutions.
But if the interval between two memorable eras could
be instantly annihilated ; if it were possible, after a
momentary slumber of two hundred years, to display
the new world to the eyes of a spectator who still re-
tained a lively and recent impression of the old, his
Surprise and his reflections would furnish the pleasing
Subject of a philosophical romance.” *

Prejudices arising from our peculiar position as in-
habitants of theland.—The sources of prejudice hitherto
“onsidered may be deemed peculiar for the most part
to the infancy of the science, but others are common
to the first cultivators of geology and to ourselves, and
are all singularly calculated to produce the same de-
Ception, and to strengthen our belief that the course of
nature in the earlier ages differed widely from that now
€stablished. Although these circumstances cannot be
ully explained without assuming some things as
Proved, which it will be the object of another part of
this work to demonstrate, it may be well to allude to
them briefly in this place.

The first and greatest difficulty, then, consists in
an habitual unconsciousness that our position as
observers is essentially unfavourable, when we en-

favour to estimate the magnitude of the changes
_ Dew in progress. In consequence of our inattention to
this Subject, we are liable to serious mistakes in con-
‘tasting the present with former states of the globe.

* Gibbon, Decline and Fall, chap. xxiii.
VOL. I. G

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As dwellers on the land, we inhabit about a fourth
part of the surface; and that portion is almost ex-
clusively a theatre of decay, and not of reproduction.
We know, indeed, that new deposits are annually
formed in seas and lakes, and that every year some
new igneous rocks are produced in the bowels of the
earth, but we cannot watch the progress of their form-
ation ; and as they are only present to our minds by
the aid of reflection, it requires an effort both of the
reason and the imagination to appreciate duly their
importance. It is, therefore, not surprising that we
estimate very imperfectly the result of operations
thus invisible to us; and that, when analogous results
of former epochs are presented to our inspection, we
cannot immediately recognize the analogy. He who
has observed the quarrying of stone from a rock, and
has seen it shipped for some distant port, and then
endeavours to conceive what kind of edifice will be
raised by the materials, is in the same predicament as
a geologist, who, while he is confined to the land, sees
the decomposition of rocks, and the transportation of
matter by rivers to the sea, and then endeavours to
picture to himself the new strata which Nature is
building beneath the waters.
Prejudices arising from our not seeing subterranean
changes.—Nor is his position less unfavourable when,
beholding a volcanic eruption, he tries to conceive
what changes the column of lava has produced, in its
passage upwards, on the intersected strata; or what
form the melted matter may assume at great depths
on cooling ; or what may be the extent of the subter-
ranean rivers and reservoirs of liquid matter far be-
neath the surface. It should, therefore, be remem-
bered, that the task imposed on those who study the

Ch. v.] THE PROGRESS OF GEOLOGY. 123

earth’s history requires no ordinary share of discretion ;
for we are precluded from collating the corresponding
Parts of the system of things as it exists now, and as
it existed at former periods. If we were inhabitants
of another element —if the great ocean were our
domain, instead of the narrow limits of the land, our
difficulties would be considerably lessened ; while, on
the other hand, there can be little doubt, although the
reader may, perhaps, smile at the bare suggestion of
Such an idea, that an amphibious being, who should
Possess our faculties, would still more easily arrive at
Sound theoretical opinions in geology, since he might
ehold, on the one hand, the decomposition of rocks in
the atmosphere, or the transportation of matter by
tunning water; and, on the other, examine the depo-
Sition of sediment in the sea, and the imbedding of
animal and vegetable remains in new strata. He
might ascertain, by direct observation, the action of a
Mountain torrent, as well as of a marine current ; might
“ompare the products of volcanos poured out upon the
and with those ejected beneath the waters ; and
Might mark, on the one hand, the growth of the forest,
Sat on the other that of the coral reef. Yet, even
With these advantages, he would be liable to fall into
© greatest errors when endeavouring to reason on
"ocks of subterranean origin. He would seek in vain,
Within the sphere of his observation, for any direct
analogy to the process of their formation, and would
erefore be in danger of attributing them, wherever
€y are upraised to view, to some “ primeval state of
Nature.”
Ca if we may be allowed so far to indulge the
agmation, as to suppose a being entirely confined to
the nether world — some « dusky melancholy sprite,”
G 2

124 PREJUDICES WHICH RETARD [Book 1.

like Umbriel, who could “flit on sooty pinions to the
central earth,” but who was never permitted to “ sully
the fair face of light,” and emerge into the regions of
water and of air; and if this being should busy himself
in investigating the structure of the globe, he might
frame theories the exact converse of those usually
adopted by human philosophers. He might infer that
the stratified rocks, containing shells and other organic
remains, were the oldest of created things, belonging
to some original and nascent state of the planet. «Of
these masses,” he might say, “ whether they consist of
loose incoherent sand, soft clay, or solid stone, none
have been formed in modern times. Every year some
part of them are broken and shattered by earthquakes,
or melted by volcanic fire ; and, when they cool down
slowly from a state of fusion, they assume a new and
more crystalline form, no longer exhibiting that stra-
tified disposition, and those curious impressions and
fantastic’ markings, by which they were previously
characterized. This process cannot have been carried
on for an indefinite time, for in that case all the stra-
tified rocks would long ere this have been fused and
crystallized. It is therefore probable that the whole
planet once consisted of these mysterious and curiously
bedded formations at a time when the volcanic fire had
not yet been brought into activity. Since that period
there seems to have been a gradual development of
heat; and this augmentation we may expect to con-
tinue till the whole globe shall be in a state of fluidity
and incandescence.”

Such might be the system of the Gnome at the very
time that the followers of Leibnitz, reasoning on what
they saw on the outer surface, might be teaching the
opposite doctrine of gradual refrigeration, and averring

Ch. v.] THE PROGRESS OF GEOLOGY. ~ 125

that the earth had begun its career as a fiery comet,
and might be destined hereafter to become a frozen
Mass. The tenets of the schools of the nether and of
the upper world would be directly opposed to each
other, for both would partake of the prejudices in-
evitably resulting from the continual contemplation of
one class of phenomena to the exclusion of another.
Man observes the annual decomposition of crystalline
and igneous rocks, and may sometimes see their con-
Version into stratified deposits; but he cannot witness
the reconversion of the sedimentary into the crystal-
line by subterranean fire. He is in the habit of re-
Sarding all the sedimentary rocks as more recent than

e unstratified, for the same reason that we may sup-
Pose him to fall into the opposite error if he saw the
origin of the igneous class only.

ASSUMPTION OF THE DISCORDANCE OF THE ANCIENT
AND EXISTING CAUSES OF CHANGE UNPHILOSO-
PHICAL.

It is only by becoming sensible of our natural dis-
3 vantages that we shall be roused to exertion, and
Prompted to seek out opportunities of observing such
0t the operations now in progress, as do not present
themselves readily to view. We are called upon, in
Our researches into the state of the earth, as in our
endeavours to comprehend the mechanism of the
‘€avens, to invent means for overcoming the limited
range of our vision. We are perpetually required to
ring, as far as possible, within the sphere of observ-
ation, things to which the eye, unassisted by art, could
never obtain access.

a3

A EN a CE —-—
oe ——~ — — =

196 ASSUMED DISCORDANCE OF [Book I-

It was not an impossible contingency, that astro-
nomers might have been placed at some period in a
situation much resembling that in which the geologist
seems to stand at present. If the Italians, for example;
in the early part of the twelfth century, had discovered
at Amalfi, instead of the pandects of Justinian, some
ancient manuscripts filled with astronomical observ-
ations relating to a period of three thousand years, and
made by some ancient geometers who possessed optical
instruments as perfect as any in modern Europe, they
would, probably, on consulting these memorials, have
come to a conclusion that there had been a great
revolution in the solar and sidereal systems. “ Many
primary and secondary planets,” they might say, “ are
enumerated in these tables, which exist no longer.
Their positions are assigned with such precision, that
we may assure ourselves that there is nothing in their
place at present but the blue ether. Where one star
is visible to us, these documents represent several
thousands. Some of those which are now single, con-
sisted then of two separate bodies, often distinguished
by different colours, and revolving periodically round
a common centre of gravity. There is nothing ana-
logous to them in the universe at present ; for they
were neither fixed stars nor planets, but seem to have
stood in the mutual relation of sun and planet to each
other. We must conclude, therefore, that there has
occurred, at no distant period, a tremendous cata-
strophe, whereby thousands of worlds have been anni-
hilated at once, and some heavenly bodies absorbed
into the substance of others.” When such doctrines
had prevailed for ages, the discovery of one of the
worlds, supposed to have been lost, by aid of the first
rude telescope invented after the revival of sciences

Ch. V] ANCIENT AND MODERN CAUSES. 127

would not dissipate the delusion, for the whole burden
of proof would now be thrown on those who insisted
on the stability of the system from a remote period,
and ‘these philosophers would be required to demon-
Strate the existence of all the worlds said to have been
annihilated.

Such popular prejudices would be most unfavourable
to the advancement of astronomy; for, instead of per-
Severing in the attempt to improve their instruments,
and laboriously to make and record observations, the
Sreater number would despair of verifying the conti-
nued existence of the heavenly bodies not visible to
the naked eye. Instead of confessing the extent of
their ignorance, and striving to remove it by bringing
to light new facts, they would indulge in the more
fasy and indolent employment of framing imaginary
theories concerning catastrophes and mighty revolu-
tions in the system of the universe.

For more than two centuries the shelly strata of the,
Subapennine hills afforded matter of speculation to the
early geologists of Italy, and few of them had any
Suspicion that similar deposits were then forming in
the neighbouring sea. They were as unconscious of
the continued action of causes still producing similar
effects, as the astronomers, in the case above sup-
Posed, of the existence of certain heavenly bodies still
Siving and reflecting light, and performing their move-
Ments as of old. Some imagined that the strata, so
rich in organic remains, instead of being due to second-
ary agents, had been so created in the beginning of
things by the fiat of the Almighty ; and others ascribed.
the imbedded fossil bodies to some plastic power
which resided in the earth in the early ages of the
World. At length Donati explored the bed of the

G4

128 ASSUMED DISCORDANCE OF [Book I

Adriatic, and found the closest resemblance between
the new deposits there forming, and those which con-
stituted hills above a thousand feet high in various parts
of the Italian peninsula. He ascertained that certain
genera of living testacea were grouped together at the
bottom of the sea, in precisely the same manner as were
their fossil analogues in the strata of the hills, and
that some species were common to the recent and
fossil world. Beds of shells, moreover, in the Adriatic,
were becoming incrusted with calcareous rock: and
others were recently inclosed in deposits of sand and
clay, precisely as fossil shells were found in the hills.
This splendid discovery of the identity of modern and
ancient submarine operations was not made without
the aid of artificial instruments, which, like the tele-
scope, brought phenomena into view not otherwise
within the sphere of human observation.

In like manner, in the Vicentin, a great series of
volcanic and marine sedimentary rocks was examined
in the early part of the last century; but no geologists
suspected, before the time of Arduino, that these were
partly composed of ancient submarine lavas. If, when
these inquiries were first made, geologists had been
told that the mode of formation of such rocks might
be fully elucidated by the study of processes then
going on in certain parts of the Mediterranean, they
would have been as incredulous as zeometers would
have been before the time of Newton, if any one had
informed them that, by making experiments on the
motion of bodies on the earth, they might discover the
laws which regulated the movements of distant planets.

The establishment, from time to time, of numerous
points of identification, drew at length from geologists
a reluctant admission, that there was more correspond-

Ch. V.j ANCIENT AND MODERN CAUSES. 129

ence between the physical constitution of the globe,
and more uniformity in the laws regulating the changes
of its surface, from the most remote eras to the present,
than they at first imagined. If, in this state of the
Science, they still despaired of reconciling every class
of geological phenomena to the operations of ordinary
Causes, even by straining analogy to the utmost limits
of credibility, we might have expected, at least, that
the balance of probability would now have been pre-
Sumed to incline towards the identity of the causes.
But, after repeated experience of the failure of
attempts to speculate on different classes of geological
phenomena, as belonging to a distinct order of things,
each new sect persevered systematically in the prin-
ciples adopted by their predecessors. They invariably

egan, as each new problem presented itself, whether
relating to the animate or inanimate world, to assume
in their theories, that the economy of nature was for-
merly governed by rules for the most part independent
of those now established. Whether they endeavoured
to account for the origin of certain igneous rocks, or
to explain the forces which elevated hills or excavated
Valleys, or the causes which led to the extinction of
Certain races of animals, they first presupposed an
Original and dissimilar order of nature ; and when at
length they approximated, or entirely came round to
an opposite opinion, it was always with the feeling,
that they conceded what they were justified à priori
in deeming improbable. In a word, the same men
who, as natural philosophers, would have been most
incredulous respecting any extraordinary deviations
from the ‘known course of nature, if reported to have
happened in their own time, were equally disposed, as

G5

130 ASSUMED DISCORDANCE OF [Book É

geologists, to expect the proofs of such deviations at
every period of the past.

I shall now proceed to enumerate some of the prin-
cipal difficulties still opposed to the theory of the uni-
formity of the causes which have worked successive
changes in the crust of the earth, and in the condition
of its living inhabitants. The discussion of so im-
portant a question on the present occasion may appear
premature, but it is one which naturally arises out of
a review of the former history of the science. It is, of
course, impossible to enter fully into such speculative
topics, without occasionally carrying the novice be-
yond his depth, and appealing to facts and conclusions
with which he must as yet be unacquainted ; but his
curiosity cannot fail to be excited by having his atten-
tion at once called to some of the principal points in
controversy, and after reading the second, third, and
fourth books, he may return again to these preliminary
essays with increased interest and profit.

First, then, it is undeniable, that many objections to
the doctrine of the uniform agency of geological causes
have been partially or entirely removed by the pro-
gress of the science during the last forty years. It
was objected, for example, to those who endeavoured
to explain the formation of sedimentary strata by
causes now in diurnal action, that they must take for
granted incalculable periods of time. Now the time
which they required has since become equally requi-
site to account for another class of phenomena brought
to light by more recent investigations. It must always.
have been evident to unbiassed minds, that. successive
strata, containing, in regular order of superposition,
distinct shells and corals, arranged in families as they
grow at the bottom of the sea, could only have been

Ch, Vi] ANCIENT AND MODERN CAUSES. 131

formed by slow and insensible degrees in a great lapse
of ages: yet, until organic remains were minutely
examined and specifically determined, it was rarely
Possible to prove that the series of deposits met with
m one country was not formed simultaneously with
that found in another. But we are now able to deter-
Mine, in numerous instances, the relative dates of
Sedimentary rocks in distant regions, and to show, by
their organic remains, that they were not of contem-
Porary origin, but formed in succession. We often
find, that where an interruption in the consecutive
formations in one district is indicated by a sudden
transition from one assemblage of fossil species to
another, the chasm is filled up, in some other district,
by important groups of strata.*

The more attentively we study the European conti-
Rent, the greater we find the extension of the whole
Series of geological formations. No sooner does the
calendar appear to be completed, and the signs of a
Succession of physical events arranged in chronolo-
gical order, than we are called upon to intercalate, as
it were, some new period of vast duration. A geolo-
gist, whose observations have been confined to England,
18 accustomed to consider the superior and newer
8roups of marine strata in our island as modern, —and
Such they are, comparatively speaking; but when he
has travelled through the Italian peninsula and Sicily,
and has seen strata of more recent origin forming
Mountains several thousand feet high, and has marked
a long series both of volcanic and submarine operations,
all newer than any of the regular strata which enter
largely into the physical structure of Great Britain, he

~ * See Book iv. chap. iii.

G 6

132 ASSUMED DISCORDANCE OF [Book I.

returns with more exalted conceptions of the antiquity
of some of our modern deposits than he before enter-
tained of the oldest of the British series.

We cannot reflect on the concessions thus extorted
from us, in regard to the duration of past time, without
foreseeing that the period may arrive when part of the
Huttonian theory will be combated on the ground of
its departing too far from the analogy of the present__
course of nature. } {On a closer investigation of extinct —
volcanos, we find proofs that they broke out at succes-
sive eras, and that the eruptions of one group were
often concluded long before others had commenced
their activity. Some were burning when one class of
organic beings were in existence, others came into
action when a different and new race of animals and
plants existed: —it is more than probable, therefore,
that the convulsions caused by subterranean move-
ments, which seem to be merely another portion of the
volcanic phenomena, have also occurred in succession ;
and their effects must be divided into separate sums,
and assigned to separate periods of time. Nor is this
all: when we examine the volcanic products, whether
they be lavas which flowed out under water, or upon
dry land, we find that intervals of time, often of great
length, intervened between their formation, and that
the effects of single eruptions were not greater in
amount than those which now result from ordinary
volcanic convulsions. The accompanying or preced-
ing earthquakes, therefore, may be considered to have
been also successive, often interrupted by ‘long inter-
vals of time, and not to have exceeded in violence those }
now experienced in the ordinary course of nature. j fJ

Already, therefore, may we regard the doctrine of
the sudden elevation of whole continents by paroxysmal

Ch. V.] ANCIENT AND MODERN CAUSES. 133

eruptions as invalidated; and there was the greatest
MCconsistency in the adoption of such a tenet by the
Huttonians, who were anxious to reconcile former
changes to the present economy of the world. It was
Contrary to analogy to suppose, that Nature had been
at any former epoch parsimonious of time and prodigal
of violence — to imagine that one district was not at
rest, while another was convulsed — that the disturb-
ing forces were not kept under subjection, so as never
to carry simultaneous havoc and desolation over the
Whole earth, or even over one great region. If it
Could have been shown, that a certain combination of
Circumstances would at some future period produce a
Crisis in the subterranean action, we should certainly
have had no right to oppose our experience for the
last three thousand years as an argument against the
Probability of such occurrences in past ages; but it is
not pretended that such a combination can be foreseen.

In speculating on catastrophes by water, we may
Certainly anticipate great floods in future; and we may
therefore presume that they have happened again and
again in past times. The existence of enormous seas
of fresh water, such as the North American lakes, the
Surface of the largest of which is elevated more than
six hundred feet above the level of the ocean, and is
m parts twelve hundred feet deep, is alone sufficient to
“ssure us, that the time may come, however distant,
When a deluge may lay waste a considerable part of
the American continent. No hypothetical agency is
Tequired to cause the sudden escape of the confined
waters. Such changes of level, and opening of fissures,
as have accompanied earthquakes since the com-
mencement of the present century, or such excavation
of ravines as the receding cataract of Niagara is now

134 ASSUMED DISCORDANCE OF [Book I.

effecting, might breach the barriers. Notwithstanding,
therefore, that we have not witnessed within the last
three thousand years the devastation by deluge of a
large continent, yet, as we may predict the future oc-
currence of such catastrophes, we are authorized to
regard them as part of the present order of Nature ;
and they may be introduced into geological specula-
tions respecting the past, provided we do not imagine
them to have been more frequent or general than we
expect them to be in time to come.

The great contrast in the aspect of the older and
newer rocks, in texture, structure, and. the derange-
ment of the strata, appeared formerly one of the
strongest grounds for presuming that the causes to
which they owed their origin were perfectly dissimilar
from those now in operation. But this incongruity
may be the result of subsequent modifications, since
the difference of relative age is demonstrated to have
been immense, so that, however slow and insensible
the change, it must have become important in the
course of so many ages. In addition to the influence
of volcanic heat, we must allow for the effect of me-
chanical pressure, of chemical affinity, of percolation
by mineral waters, of permeation by elastic fluids, and
the action, perhaps, of many other forces less under-
stood, such as electricity and magnetism. The ex-
treme of alteration which may thus be effected, is
probably exemplified in the highly crystalline, or gra-
nitiform, strata, to which the name of primary is
usually given; but the theory of their origin must be
postponed to the concluding chapters of the fourth
Book.

In regard to the signs of the upraising, sinking,
fracture, and contortion of rocks, it is evident that

Ch, V.J ANCIENT AND MODERN CAUSES. 135

newer strata cannot be shaken by earthquakes, unless
the Subjacent rocks are also affected ; so that the con-
trast in the relative degree of disturbance in the more
ancient and the newer strata, is one of, many proofs
that the convulsions have happened in different eras,
and the fact confirms the uniformity of the action of
Subterranean forces, instead of their greater violence
in the primeval ages.

Doctrine of Universal Formations.— The popular
doctrine of universal formations, or the unlimited geo-
Sraphical extent of strata, distinguished by similar
Mineral characters, appeared for a long time.to present
insurmountable objections to the supposition, that the
farth’s crust had been formed by causes now acting.
If it had merely been assumed, that rocks originating
from fusion by subterranean fire presented in all parts
f the globe a perfect correspondence in their mineral
Composition, the assumption would not have been
€xtravagant ; for, as the elementary substances that
enter largely into the composition of rocks are few in
number, they may be expected to arrange them-
Selves invariably in the same forms, whenever the
elementary particles are freely exposed to the action
of chemical affinities. But when it was imagined that
Sedimentary mixtures, including animal and vegetable
remains, and evidently formed in the beds of an-
cient lakes and seas, were of a homogeneous nature
throughout a whole hemisphere, the dogma pre-
cluded at once all hope of recognizing the slightest
malogy between the ancient and modern causes of
decay and reproduction. We know that existing
"Ivers carry down from different mountain chains
Sediment of distinct colours and composition : where
the chains are near the sea, coarse sand and gravel

136 ASSUMED DISCORDANCE OF [Book I.

is swept in; where they are distant, the finest mud.
We know, also, that the matter introduced by springs
into lakes and seas is very diversified in mineral
composition; in short, contemporaneous strata now in
the progress of formation are greatly varied in their
composition, and could ‘never afford formations of
homogeneous mineral ingredients co-extensive with
the greater part of the earth’s surface.

This theory, however, is in truth as inapplicable to
the geological monuments found in the earth’s crust;
as to the effects of existing causes. The first investi-
gators of sedimentary rocks had never reflected on the
great areas occupied by the modern deltas of large
rivers; still less on the much greater areas over which

marine currents, preying alike on river-deltas, and
continuous lines of sea-coast, diffuse homogeneous
mixtures. They were ignorant of the vast spaces over

which calcareous and other mineral springs abound
upon the land and in the sea, especially in and near
volcanic regions, and of the quantity of matter dis-
charged by them. When, therefore, they ascertained
the extent of the geographical distribution of certain
groups of ancient strata — when they traced them con-
tinuously from one extremity of Europe to the other,
and found them flanking, throughout their entire range;
great mountain chains, they were astonished at so un-
expected a discovery; and, considering themselves at
liberty to disregard all modern analogy, they indulged
in the sweeping generalization, that the law of conti-
nuity prevailed throughout Strata of contemporaneous
origin over the whole planet. The difficulty of dissi-
pating this delusion was extreme, because some rocks;
formed under similar circumstances at different epochs;
present the same external characters, and often the

Ch. V.J ANCIENT AND MODERN CAUSES. 137

same internal composition; and all these were assumed
to be contemporaneous until the contrary could be
shown, which, in the absence of evidence derived from
direct superposition, and in the scarcity of organic re-
Mains, was often impossible.

Innumerable other false generalizations have been
derived from the same source; such, for instance, as
the former universality of the ocean, now disproved by
the discovery of the remains of terrestrial vegetation
in strata of every age, even the most ancient. But I
shall dwell no longer on exploded errors, but proceed
oe once to contend against weightier objections, which
Will require more attentive consideration. |

CHAPTER VI.

FURTHER EXAMINATION OF THE QUESTION AS TO THE
DISCORDANCE OF THE ANCIENT AND MODERN CAUSES OF
CHANGE.

Proofs that the climate of the Northern Hemisphere was formerly
hotter — Direct proofs from the organic remains of the Sicilian

and Italian strata— Proofs from analogy derived from extinct

Quadrupeds — Imbedding of animals in Icebergs — Siberian
Mammoths (p. 144.) — Evidence in regard to temperature,
from the fossils of tertiary and secondary rocks (p. Lore
From the Plants of the Coal formation — Northern limit of
these fossils — Whether such plants could endure the long con-
tinuance of an arctic night (p. 159.).

Climate of the Northen Hemisphere formerly hotter. —
Tuar the climate of the Northern hemisphere has un-
dergone an important change, and that its mean annual
temperature must once have resembled that now ex-
perienced within the tropics, was the opinion of some
of the first naturalists who investigated the contents
of the ancient strata. Their conjecture became more
probable when the shells and corals of the secondary
rocks were more carefully examined ; for these organic
remains were found to be intimately connected by
generic affinity with species now living in warmer
latitudes. Ata later period, many reptiles, such as
turtles, tortoises, and large saurian animals, were dis-
covered in European formations in great abundance ;
and they supplied new and powerful arguments, from
analogy, in support of the doctrine, that the heat of

Ch. VIJ CHANGE OF CLIMATE. 139

the climate had been great when our secondary strata _
` Were deposited. Lastly, when the botanist turned his
attention to the specific determination of fossil plants,
the evidence acquired the fullest confirmation ; for the
flora of a country is peculiarly influenced by temper-
ature: and the ancient vegetation of the earth might,
more readily than the forms of animals, have afforded
conflicting proofs, had the popular theory been without
foundation. When the examination of animal and
Vegetable remains was extended to rocks in the most
hothern parts of Europe and North America, and
even to the Arctic regions, indications of the same
revolution in climate were discovered.

It cannot be said, that in this, as in many other de-
partments of geology, we have investigated the phe-
nomena of former eras, and neglected those of the
present state of things. On the contrary, since the
first agitation of this interesting question, the acces-
sions to our knowledge of living animals and plants
have been immense, and have far surpassed all the
data previously obtained for generalizing, concerning
the relation of certain types of organization to parti-
cular climates. The tropical and temperate zones of
South America and of Australia have been explored ;
and, on close comparison, it has been found, that
Scarcely any of the species of the animate creation in
these extensive continents are identical with those in-
habiting the old world. Yet the zoologist and botanist,
well acquainted with the geographical distribution of
organic beings in other parts of the globe, would have
been able, if distinct groups of species had been pre-
sented to them from these regions, to recognize those
which had been collected from latitudes within, and
those which were brought from without the tropics.

140 CHANGE OF CLIMATE [Book I.

Before I attempt to explain the probable causes of
great vicissitudes of temperature on the earth’s sur-
face, I shall take a rapid view of some of the principal
data which appear to support the popular opinions
now entertamed on the subject. To insist on the
soundness of these inferences, is the more necessary,
because some zoologists have of late undertaken to
vindicate the uniformity of the laws of nature, not by
accounting for former fluctuations in climate, but by
denying the value of the evidence in their favour.*

Direct proofs from the fossil remains of living species
—It is not merely by reasoning from analogy that we
are led to infer a diminution of temperature in the
climate of Europe ; there are direct proofs in con-
firmation of the same doctrine, in the only countries
hitherto investigated by expert geologists where we
could expect to meet with such proofs. It is not in
England or Northern France, but around the borders
of the Mediterranean, from the South of Spain to
Calabria, and in the islands of the Mediterranean, that
we must look for conclusive evidence on this question ;
for it is not in strata where the organic remains belong
to extinct species, but where living species abound in
a fossil state, that a theory of climate can be subjected
to the experimentum crucis. In Sicily, Ischia, and
Calabria, where the fossil testacea of the more recent
strata belong almost entirely to species now inhabiting
the Mediterranean, the conchologist remarks, that in-
dividuals in the inland deposits often exceed in their
average size their living analogues, as if the circum-

* See two articles by the Rev. Dr. Fleming, in the Edinburgh
New Phil. Journ. No. xii. p. 277., April, 1829; and No. xv.
P. 65., Jan. 1830. —

€h, VLJ IN THE NORTHERN HEMISPHERE 141

stances under which they formerly lived were more
favourable to their development. Yet no doubt can
be entertained of their specific identity on the ground
of such difference in their dimensions ; because living
individuals of many of these species still attain, in
warmer latitudes, the average size of the fossils.

I collected several hundred species of shells in Sicily,
at different elevations, sometimes from one thousand —
to three thousand feet above the level of the sea; and
forty species or more in Ischia, partly from an eleva-
tion of above one thousand feet, and these were care-
fully compared with recent shells procured by Pro-
fessor O. G. Costa, from the Neapolitan seas. Not
Only were the fossil species for the most part identical
with those now living, but the relative abundance in
which different species occur in the strata and in the
Sea corresponds in a remarkable manner. Yet the
larger average size of the fossil individuals of many
Species was very striking. A comparison of the fossil
Shells of the more modern strata of Calabria and
Otranto, in the collection of Professor Costa, afforded
similar results.

As we proceed northwards in the Italian peninsula,
and pass from the region of active to that of extinct
Volcanos, we find the assemblage of fossil shells, in the
Modern (Subapennine) strata, to depart somewhat
More widely from the type of the neighbouring seas.
The proportion of species identifiable with those now
living in the Mediterranean is still considerable ; but
it no longer predominates, as in the South of Italy,
Over the unknown species. Although occurring in
localities which are removed several degrees farther
from the equator (as at Sienna, Parma, Asti, &c-), the
Shells yield clear indications of a hotter climate. Many

142 CHANGE OF CLIMATE [Book]

of them are common to the Subapennine hills, to the
Mediterranean, and to the Indian Ocean. Those in
the fossil state, and their living analogues from the
tropics, correspond in size ; whereas the individuals of
the same species from the Mediterranean are dwarfish
and appear degenerate, and stunted in their growth,
for want of conditions which the Indian Ocean still
supplies.*

This evidence is of great weight, and is not neu-
tralized by any facts of a conflicting character; such,
for instance, as the association, in the same group, of
individuals referable to species now confined to arctic
regions. Whenever any of the fossil shells are identi-
fied with living species foreign to the Mediterranean,
it is not in the Northern Ocean, but between the
tropics, that they must be sought + : on the other hand,
the associated unknown species belong, for the most
part, to genera which are now most largely developed

* Professors Guidotti of Parma, and Bonelli of Turin, pointed
out to me, in 1828, many examples in confirmation of this point :
thus the common Orthoceras of the Mediterranean, (0. raphanista,)

was said to attain larger average dimensions in a fossil, than in a

recent state.

t Thus, for example, Rostellaria curvirostris, found fossil by
Signor Bonelli near Turin, is only known at present in the Red
Sea. Murex cornutus, fossil at Asti, is now only known recent in
warmer latitudes; Senegal being the principal known habitat at
present. Conus antediluvianus cannot be distinguished from a
shell now brought from Owhyhee. Among other familiar in-
stances mentioned to me by Italian naturalists, in confirmation of
the same point, Buccinum clathratum, Lam., was cited; but Pro-
fessor Costa assured me that this shell, although extremely rare,
still occurs in the Mediterranean. M. Deshayes informs me that
he has received it from the Indies.

Ch. VLJ IN THE NORTHERN HEMISPHERE. 143

in €quinoctial regions, as, for example, the genera
Pleurotoma and Cyprea.*

On comparing the fossils of the tertiary deposits of
Paris and London with those of Bordeaux, and these
again with the more modern strata of Sicily, we should
at first expect that they would each indicate a higher
temperature in proportion as they are situated farther
to the south. But the contrary is true; many shells
are common to all these groups, and some of them,
both freshwater and marine, are of species still living.
Those found in the older, or Eocene, deposits of Paris
and London, although six or seven degrees to the north
of the Miocene strata at Bordeaux, afford evidence of
àa warmer climate; while those of Bordeaux imply
that the sea in which they lived was of a higher temper-
ature than that of Sicily, where the shelly strata were
formed six or seven degrees nearer to the equator. In
these cases the greater antiquity of the several forma-
tions (the Parisian being the oldest and the Sicilian the
Newest) has more than counterbalanced the influence
Which latitude would otherwise exert, and this phenome-
en clearly points to a gradual refrigeration of climate.

* Of the genus Pleurotoma a very few living
representatives have yet been found in the Medi-
terranean ; yet no less than twenty-five species
were to be seen in the museum at Turin, in

#1828, all procured by Professor Bonelli from the
Subapennine strata of northern Italy. The genus
Cyprza is represented by many large fossil species
in the Subapennine hills.

Pleuroioma rotata. Subapennine hills, Italy. (a)

(

a) For another figure of this species, and of P. vulpecula, see Vol. IV. plate 10.

144 CHANGE OF CLIMATE. [Book I.

¢

Siberian Mammoths.—In the superficial deposits of
sand, gravel, and loam, strewed very generally over all
parts of Europe, the remains of extinct species of land
quadrupeds have been found, especially in places
where the alluvial matter appears to have been washed
into small lakes, or into depressions in the plains bor-
dering ancient rivers. Similar deposits have also
been lodged in rents and caverns of rocks where they
may have been swept in by land floods, or introduced
by engulphed rivers during changes in the physical
geography of countries. The various circumstances
under which the bones of animals have been thus pre-
served will be more fully considered hereafter*; I
shall only state here, that among the extinct mam-
malia thus entombed, we find species of the elephant,
rhinoceros, hippopotamus, bear, hyzena, lion, tiger,
and many others; consisting for the most part of
genera now confined to warmer regions.

It has been inferred that the same change of climate
which has caused certain Indian species of testacea to
become rare, or to degenerate in size, or to disappear
from the Mediterranean, —and certain genera of the
Subapennine hills, now exclusively tropical, to retain
no longer any representatives in the adjoining seas, —
may also have contributed to the annihilation of the
mammiferous genera which formerly inhabited the
continents. It is certainly probable that, when these
animals abounded in Europe, the climate was milder
than that now experienced, but they by no means
appear to have required a tropical heat. The hippopo-
tamus is now only met with in rivers where the temper-
ature of the water is warm and nearly uniform, but the

* Book iii. chaps. 14, 15, &c.

Ch. VL] - SIBERIAN MAMMOTHS. 145

great fossil species of the same genus (H. major, Cuv.)

Certainly inhabited England when the testacea of our
country were nearly the same as those now existing,
and when the climate cannot be supposed to have been
very hot. The bones of this animal have lately been
found by Mr. Strickland, together with those of a bear
and other mammalia, at Cropthorn, near Evesham, in
Worcestershire, in alluvial sand, together with twenty-
three species of terrestrial and freshwater shells, all,
with two exceptions, of British species. The bed of
Sand, containing the shells and bones, reposes on lias,
and is covered with alternating strata of gravel, sand
and loam.*

The mammoth also appears to have existed in Eng-
land when the temperature of our latitudes could not
have been very different from that which now prevails ;
for remains of this animal have been found at North
Clif in the county of York, in a lacustrine formation,
in which all the land and freshwater shells, thirteen in
number, can be identified with species and varieties
how existing in that county. Bones of the bison also,
an animal now inhabiting a cold or temperate climate,
have been found in the same place. That these quad-
Tupeds, and the indigenous species of testacea asso-
ciated with them, were all contemporary inhabitants of
Yorkshire, has been established by unequivocal proof.
The Rev. W. V. Vernon Harcourt caused a pit to be
Sunk to the depth of twenty-two feet through undis-
turbed strata, in which the remains of the mammoth
were found imbedded, together with the shells, in a
deposit, which had evidently resulted from tranquil
waters.+

* Geol. Proceedings, No. 36. June, 1834.

+ Phil. Mag., Sept. 1829 and Jan. 1830.
VOL. I. H

146 CHANGE OF CLIMATE, [Book TI.

When reasoning on these phenomena, the reader
must always bear in mind that the fossil individuals
belonged to species of elephant, rhinoceros, hippopo-
tamus, bear, tiger, and hyena, distinct from those
which now dwell within or near the tropics. Dr.
Fleming, in a discussion on this subject, has well re-
marked that a near resemblance in form and osteolo-
gical structure is not always followed, in the existing
creation, by a similarity of geographical distribution ;
and we must therefore be on our guard against decid-
ing too confidently, from mere analogy of anatomical
structure, respecting the habits and physiological pecu-
liarities of species, now no more. “The zebra delights
to roam over the tropical plains, to which it is ina great
measure restricted ; while the horse can maintain its
existence throughout an Iceland winter. The buffalo,
like the zebra, prefers a high temperature, and cannot
thrive even where the common ox prospers. The musk
ox, on the other hand, though nearly resembling the
buffalo, prefers the stinted herbage of the arctic re-
gions, and is able, by its periodical migrations, to out-
live a northern winter. The jackal (Canis aureus)
inhabits Africa, the warmer parts of Asia, and Greece ;
while the isatis (Canis lagopus) resides in the arctic
regions. The African hare and the polar hare have
their geographical distribution expressed in their trivial
names* ;” and different species of bears thrive in tro-
pical, temperate, and arctic latitudes.

Recent investigations have placed beyond all doubt
the important fact that a species of tiger, identical
with that of Bengal, is common in the neighbourhood
‘of Lake Aral, near Sussac, in the forty-fifth degree of

* Fleming, Ed. New Phil. Journ., No, 12, p. 282. 1829.

Ch. VL] SIBERIAN MAMMOTHS. 147

north latitude ; and from time to time this animal is —
now seen in Siberia, in a latitude as far north as the
parallel of Berlin and Hamburgh.* Humboldt re-
marks that the part of southern Asia now inhabited by |
this Indian species of tiger is separated from the Hima-
laya by two great chains of mountains, each covered
with perpetual snow,—the chainof Kuenlun, lat. 35° N.,
and that of Mouztagh, lat. 42°,—so that it is impossible
that these animals should-merely have made excursions
from India, so as to have penetrated in summer to the
forty-eighth and fifty-third degrees of north latitude.
They must remain all the winter north of the Mouz-
tach, or Celestial Mountains. The last tiger killed, in
1828, on the Lena, in lat. 524°, was in a climate colder
than that of Petersburgh and Stockholm.+

We learn from Mr. Hodgson’s account of the mam-
malia of Nepal, that the tiger is sometimes found at
the very edge of perpetual snow in the Himalaya f ; and
Pennant mentions that it is found among the snows of
Mount Ararat in Armenia. |

A new species also of panther (Felis irbis), covered
with long hair, has been discovered in Siberia, evidently
inhabiting, like the tiger, a region north of the Celestial
Mountains, which are in lat. 42°.9°

The two-horned African rhinoceros occurs without
the tropics at the Cape of Good Hope, in lat. 34°
29’ S., where it is accompanied by the elephant, hippo-
potamus, and hyena. Here the migration of all these
Species towards the south is arrested by the ocean ;

* Humboldt, Fragmens de Géologie, &¢., tome ii. p. 388-
Ehrenberg, Ann. des Sci. Nat., tome xxi. p- 387.
+ Ehrenberg, ibid. p. 390.
+ Journ. of Asiat. Soc., vol.i. p. 240.
§ Ehrenberg, ibid.
H 2

148 CHANGE OF CLIMATE [Book 1.

but, if the continent had been prolonged still farther,
and the land had been of moderate elevation, it is very
probable that they might have extended their range to
a greater distance from the tropics.

Now, if the Indian tiger can range in our own times
to the southern borders of Siberia, or skirt the snows
of the Himalaya, we may easily imagine that large

* species of the same genus may once have inhabited our
temperate climates. The mammoth (E. primigenius),
already alluded to as occurring fossil in England, was
decidedly different from the two existing species of
elephants, one of which is limited to Asia, south of
the 31° of N. Jat., the other to Africa, where it ex-
tends, as before stated, as far south as the Cape of
Good Hope. The bones of the great fossil species
are very widely spread over Europe and North Ame-
rica; but are nowhere in such profusion as in Siberia,
particularly near the shores of the frozen ocean. Are
we, then, to conclude that this animal preferred a polar
climate? If so, by what food was it sustained, and
why does it not still survive near the arctic circle ?

Pallas and other writers describe the bones of the
mammoth as abounding throughout all the Lowland of
Siberia, stretching in a direction west and east, from
the borders of Europe to the extreme point nearest
America, and south and north, from the base of the
mountains of central Asia to the shores of the arctic
sea. (See map, p- 149.) Within this space, scarcely
inferior in area to the whole of Europe, fossil ivory has
been collected almost every where, on the banks of the
Irtish, Oby, Yenesei, Lena, and other rivers. The ele-
phantine remains do not occur in the marshes and low
plains, but where the banks of the rivers present lofty '
precipices of sand and clay; from which circumstance

MAP OF SIBERIA.

wiljuiskoi $

Greenwich

g
2
ss

ast

E

j:

Y Krasnojarsk

Longitude

Map showing the course of the Siberian rivers from south to north, from temperate to arctic regions, in the country where the foss
bones of the Mammoth abound. ;

150 ‘ CHANGE OF CLIMATE. [Book I.

Pallas very justly inferred that, if sections could be
obtained, similar bones might be found in all the
elevated lands intervening between the great rivers.
Strahlenberg, indeed, had stated, before the time
of Pallas, that wherever any of the great rivers over-
flowed and cut out fresh channels during floods, more
fossil remains of the same kind were invariably disclosed.

As to the position of the bones, Pallas found them
in some places imbedded together with marine re-
mains ; in others, simply with fossil wood, or lignite,
such, as he says, might have been derived from ‘car-
bonized peat. On the banks of the Yenesei, below the
city of Krasnojarsk, in lat. 56°, he observed grinders,
and bones of elephants, in strata of yellow and red loam,
alternating with coarse sand and gravel, in which was
also much petrified wood of the willow and other trees.
Neither here nor in the neighbouring country were
there any marine shells, but merely layers of black
coal.* But grinders of the mammoth were collected
much farther down the same river, near the sea, in
lat. 70°, mixed with marine petrifactions.t Many
other places in Siberia are cited by Pallas, where sea
shells and fishes’ teeth accompany the bones of the
mammoth, rhinoceros, and Siberian buffalo, or bison
(Bos priscus). But it is not on the Oby nor the Ye-
nesei, but on the Lena, farther to the east, where, in
the same parallels of latitude, the cold is far more
intense, that fossil remains have been found in the
most wonderful state of preservation. In 1772, Pallas
obtained from Wiljuiskoi, in lat. 64°, from the banks of
the Wiljui, a tributary of the Lena, the carcass of a
rhinoceros (R. tichorhinus), taken from the sand in `

* Pallas, Reise in Russ. Reiche, pp. 409, 410.
+ Nov. Com. Petrop, vol, 17. p. 584.

Ch. VL] SIBERIAN MAMMOTHS. 151

which it must have remained congealed for ages, the
soil of that region being always frozen to within a
Slight depth of the surface. This carcass was com-
pared to a natural mummy, and emitted an odour like
putrid flesh, part of the skin being still covered with
black and gray hairs. So great, indeed, was the quan-
tity of hair on the foot and head conveyed to St.
Petersburg, that Pallas asked whether the rhinoceros of
the Lena might not have been an inhabitant of the tem-
perate regions of middle Asia, its clothing being so much .
warmer than that of the African rhinoceros.*

After more than thirty years, the entire carcass of
a mammoth (or extinct species of elephant) was
obtained in 1803, by Mr. Adams, much farther to the
north. It fell from a mass of ice, in which it had been
encased, on the banks of the Lena, in lat. 70°; and so
perfectly had the soft parts of the carcass been pre-
served, that the flesh, as it lay, was devoured by wolves
and bears. This skeleton is still in the museum of St.
Petersburg, the head retaining its integument and
many of the ligaments entire. The skin of the animal
was covered, first, with black bristles, thicker than
horse hair, from twelve to sixteen inches in length;
Secondly, with hair of a reddish brown colour, about
four inches long ; and thirdly, with wool of the same
colour as the hair, about an inch in length. Of the
fur, upwards of thirty pounds’ weight were gathered
from the wet sand-bank. The individual was nine feet.
high and sixteen feet long, without reckoning the
large curved tusks: a size rarely surpassed by the
largest living male elephants.+

* Nov. Com. Petrop. vol.17. p. 591.
+ Journal du Nord, St. Petersburg, 1807.
H 4

= SSS
en ae cas

= ———— = = E SS —— =
= E nE — ——

152 CHANGE OF CLIMATE [Book L.

It is evident, then, that the mammoth, instead of
being naked, like the living Indian and African ele-
phants, was enveloped in a thick shaggy covering of fur,
probably as impenetrable to rain and cold as that of
the musk ox.* The species may have been fitted by
nature to withstand the vicissitudes of a northern
climate ; and it is certain that, from the moment when
the carcasses, both of the rhinoceros and elephant»
above described, were buried in Siberia, in latitiudes
64° and 70° N., the soil must have remained frozen,
and the atmosphere nearly as cold as at this day.

* Fleming, Ed. New Phil. Journ., No. xii., p. 285.

Bishop Heber informs us (Narr.! of a Journey through the
Upper Provinces of India, vol. ii. p. 166-—219.), that in the
lower range of the Himalaya mountains, in the north-eastern
borders of the Delhi territory, between lat. 29° and 30°, he saw
an Indian elephant of a small size, covered with shaggy hair. But
this variety must be exceedingly rare; for Mr. Royle (late super-
intendant of the East India Company’s Botanic Garden at Saha-
runpore) has assured me, that being in India when Heber’s Jour-
nal appeared, and having never seen or heard of such elephants,
he made the strictest inquiries respecting the fact, and was never
able to obtain any evidence in corroboration. Mr. Royle resided
at Saharunpore, lat. 30° N., upon the extreme northern limit of the
range of the elephant. Mr. Everest also declares that he has been
equally unsuccessful in finding any one aware of the existence of
such a variety or breed of the animal, though one solitary indivi-
dual was mentioned to him as having been seen at Delhi, with a
good deal of long hair upon it. The greatest elevation, says Mr.
E., at which the wild elephant is found in the mountains to the
north of Bengal, is at a place called Nahun, about 4000 feet above
the level of the sea, and in the 31st degree of N. lat., where the
mean yearly temperature may be about 64° Fahrenheit, and the
difference between winter and summer very great, equal to about
36° F., the month of January averaging 45°, and June, the hottest
month, 81° F. (Everest on Climate of Foss, Eleph., Journ. of
Asiat, Soc., No. 25. p. 21.)

Ch. i 7 SIBERIAN MAMMOTHS. 153

So fresh is the ivory throughout northern Russia,
that, according to Tilesius, thousands of fossil tusks
have been collected and used in turning ; yet others
are still procured and sold in great plenty. He de-
clares his belief that the bones still left in northern
Russia must greatly exceed in number all the ele-
Phants now living on the globe.

We are as yet ignorant of the entire geographical
tange of the mammoth ; but its remains have recently
been collected from cliffs of frozen mud and ice on
the east side of Behring’s Straits, in Eschscholtz’s Bay,
in Russian America, lat. 66° N. As the cliffs waste }
away by the thawing of the ice, tusks and bones fall |
out, and a strong odour of animal matter is exhaled |
from the mud.*

On considering all the facts above enumerated, it
‘Seems reasonable to imagine that a large region in
Central Asia, including, perhaps, the southern half of ;
Siberia, enjoyed, at no very remote pericd in the earth’s
history, a temperate climate, sufficiently mild to afford
food for large herds of elephants and rhinoceroses, of
Species distinct from those now living. At the time
to which these speculations refer, the Lowland of
Siberia was probably less extensive towards the north
than it is now; but the existing rivers, though of
inferior length, may have flowed from south to north,
as at present, and, during inundations, may have swept
the carcasses of drowned animals into lakes, or the
Sea, as do the Nile, Ganges, and other rivers in our
Own time.+

In Siberia all the principal rivers are liable, like the

* See Dr. Buckland’s description of these bones, APRE! 19
Beechey’s Voy.

ft See Book iii. chaps. xv. and xvi.

H 5

154 CHANGE OF CLIMATE, [Book I.

Mackenzie, in North America, to remarkable floods, in
consequence of flowing in a direction from south to
north ; for they are filled with running water in their
upper course when completely frozen over for several
hundred miles near their mouths. (See map, p. 149.)
Here they remain blocked up by ice for six months
in every year, and the descending waters, finding no
open channel, rush over the ice; often changing their
direction ; and sweeping along forests and prodigious
quantities of soil and gravel mixed with ice. The
rivers of this great country are among the largest in
the world, the Yenesei having a course of 2500, the
Lena of 2000 miles; so that we may easily conceive
that the bodies of animals which fall into their waters
may be transported to vast distances towards the arctic
sea, and, before arriving there, may be stranded upon
and often frozen into thick ice, and afterwards, when
the ice breaks up, be floated still farther towards the
ocean, until at length they become buried in fluviatile
and submarine deposits near the mouths of rivers.

Humboldt remarks that near the mouths of the Lena
a considerable thickness of frozen soil may be found at
all seasons at the depth of a few feet; so that if a
carcass be once imbedded in mud in such a region and
in such a climate, its putrefaction may be arrested for
indefinite ages.*

It would doubtless be impossible for herds of mam-
moths and rhinoceroses to obtain subsistence at pre-
sent, even in the southern part of Siberia, covered as
it is during a great part of the year with snow: but
there is no difficulty in supposing a vegetation capable _
of nourishing these great quadrupeds to have once
flourished between the latitudes 40° and 60° N., re-

* Humboldt, Fragmens Asiatiques, tom. ii, p. 393.

Ch: VI] SIBERIAN MAMMOTHS. 155

sembling perhaps that of England; for we have seen
` that there are proofs of the mammoth having co-
existed with a large proportion of the living species of
British testacea.

It has been well observed by Dr. Fleming, that “ the
kind of food which:the existing species of elephant
prefers will not enable us to determine, or even to
offer a probable conjecture, concerning that of the ex-
tinct species. No one acquainted with the gramineous
character of the food of our fallow-deer, stag, or roe,
would have assigned a lichen to the rein-deer.”

Travellers mention that, even now, when the climate
of eastern Asia is so much colder than the same
parallels of latitude farther west, there are woods not
only of fir, but of birch, poplar, and alder on the
banks of the Lena as far north as latitude 60°. For- ,
merly, when the arctic lands were less extensive, the
temperature of the winter and summer may have been |
more nearly equalized, and the increasing severity of
the winters, rather than a diminution of the mean
annual temperature, may have been the chief cause of
the extermination of the mammoth. It is probable
that the refrigeration of the climate of north-eastern
Asia was accompanied, and in a great measure caused,
by changes in its physical geography. The whole
country, from the mountains to the sea, may have
been upraised by a movement similar to that which
is now experienced in part of Sweden ; and as the
shores of the Gulf of Bothnia are extended not only
by the influx of sediment brought down by rivers, but
also by the elevation and consequent drying up of the
bed of the sea, so a similar combination of causes may
have extended the low tract of land where marine
shells and fossil bones now occur in Siberia.

H 6

£

156 GEOLOGICAL PROOFS OF [Book I.

It has been suggested, that as, in our own times, the
northern animals migrate, so the Siberian elephant
and rhinoceros may have wandered towards the north
in summer. The musk oxen annually desert their
winter quarters in the south, and cross the’sea upon
the ice, to graze for four months, from May to Sep-
tember, on the rich pasturage of Melville Island, in
lat. 75”. The mammoths, without passing so far be-
yond the arctic circle, may nevertheless have made
excursions, during the heat of a brief northern summer,
from the central or temperate parts of Asia to the
sixtieth parallel of latitude; in which case the carcasses
of such as were drowned, or overwhelmed by drift
snow, may have been hurried down into the polar sea,
and imbedded in the deposits there accumulating.

I have been informed by Dr. Richardson, that in the
northern parts of America, comprising regions now
inhabited by many herbivorous quadrupeds, the drift
snow is often converted into permanent glaciers. It is
commonly blown over the edges of steep cliffs, so as to
form an inclined talus hundreds of feet high; and when
a thaw commences, torrents rush from the land, and
throw down from the top of the cliff alluvial soil and
gravel. This new soil soon becomes covered with
vegetation, and protects the foundation of snow from
the rays of the sun. Water occasionally penetrates
into the crevices and pores of the snow; but, as it soon
freezes again, it serves the more rapidly to consolidate
the mass into a compact iceberg. It may sometimes
happen that cattle grazing in a valley at the base of
such cliffs, on the borders of a sea or river, may be
overwhelmed, and at length enclosed in solid ice, and
then transported towards the polar regions. |

The result of these investigations, therefore, may

bisag- CHANGE OF CLIMATE . 157

lead us to conclude that the mammoth, and some other
extinct quadrupeds fitted to live in high latitudes, were
inhabitants of northern Asia at a time when the
climate was milder, and more uniform, than at present.
Their extermination was probably connected with
changes in the physical geography of the arctic re-
gions, of which I shall consider the effects in the next
chapter. :

Change of climate proved by fossils in older strata. —
If we pass from the consideration of these more modern
deposits, whether of marine or continental origin, in
Which existing species are abundantly intermixed with
the extinct, to the older tertiary strata, we can only
reason from analogy; since none of the species of ver-
tebrated animals, and scarcely any of the testacea of
those formations, are identifiable with species now in
being. In the deposits of that more remote period, we
find the remains of many animals analogous to those of
hot climates, such as the crocodile, turtle, and tortoise,
together with many large shells of the genus nautilus,
and plants indicating such a temperature as is now
found along the southern borders of the Mediter-
ranean.

A great interval of time appears to have elapsed
between the formation of the secondary strata, which
Constitute the principal portion of the elevated land in
Europe, and the origin of the last-mentioned Eocene
deposits. In that great series of secondary rocks,
many distinct assemblages of organized fossils are
entombed, all of unknown species, and many of them
referable to genera and families now most abundant
between the tropics. Among the most remarkable are
many gigantic reptiles, some of them herbivorous,
others carnivorous, and far exceeding in size any now

158 GEOLOGICAL PROOFS OF [Book I.

known even in the torrid zone. The genera are for
the most part extinct, but some of them, as the cro-
codile and monitor, have still representatives in the
warmer parts of the earth. Coral reefs also were evi-
dently numerous in the seas of the same periods, and
composed of species belonging to genera now charac-
teristic of a tropical climate. The number of very
large chambered shells also leads us to infer an elevated
temperature ; and the associated fossil plants, although
imperfectly known, tend to the same conclusion, the
Cycadez constituting the most numerous family.

But it is from the more ancient coal deposits that
the most extraordinary evidence has been supplied in
proof of the former existence of an extremely hot
climate in those latitudes which are now the temperate
and colder regions of the globe. It appears from the
fossils of the carboniferous period, that the flora con-
sisted almost exclusively of large vascular cryptogamic
plants. We learn, from the labours of M. Ad. Brong-
niart, that there existed at that epoch Equiseta up-
wards of ten feet high, and from five to six inches in
diameter ; tree ferns, or plants allied to them, from
forty to fifty feet in height; and arborescent Lycopo-
diaceze, from sixty to seventy feet high.* Of the above
classes of vegetables, the species are all small at pre-
sent in cold climates ; while in tropical regions there
occur, together with small species, many of a much
greater size, but their development, even in the hottest
parts of the globe, is now inferior to that indicated by
the petrified forms of the coal formation. An elevated
and uniform temperature, and great humidity in the air,
are the causes most favourable to the numerical pre-

* Consid. Générales sur la Nature de la Végétation, &c. Ann.
des Sci. Nat., Nov. 1828.

Ch. VJ CHANGE OF CLIMATE. 159

dominance and the great size of these plants within the
torrid zone at present. It is true that, as the fossil flora
consists of such plants as may accidentally have been
floated into seas, lakes, or estuaries, it may very com-
monly give a false representation of the numerical
relations of families then living ontheland. Yet, after
allowing for liability to error on these grounds, the
argument founded on the comparative numbers of the
fossil plants of the carboniferous strata is very strong.

“In regard to the geographical extent of the ancient
vegetation, it was not confined,” says M. Brongniart,
“to a small space, as to Europe, for example ; for the
same forms are met with again at great distances.
Thus, the coal plants of North America are, for the
most part, identical with those of Europe, and all be-
long to the same genera. Some specimens, also, from
Greenland, are referable to ferns, analogous to those
of our European coal mines.” *

The fossil plants brought from Melville Island,
although in a very imperfect state, have been sup-
posed to warrant similar conclusions t; and assuming
that they agree with those of Baffin’s Bay, mentioned
by M. Brongniart, how shall we explain the manner in
which such a vegetation lived through an arctic night
of several months’ duration ? {

It may seem premature to discuss this question,

* Prodrome d’une Hist. des Végét. Foss. p. 179.

+ Konig, Journ. of Sci. vol. xv. p. 20. Mr. Konig informs
me, that he no longer believes any of these fossils to be tree ferns,
as he at first stated, but that they agree with tropical forms of plants
in our English coal-beds. The Melville Island specimens, NOW
in the British Museum, are very obscure impressions.

ł Fossil Flora of Great Britain, by John Lindley and William
Hatton, Esqrs. No. IV.

160 FOSSIL PLANTS. =" [Book I.

until the true nature of the fossil flora of the arctic
regions has been more accurately determined ; yet, as
the question has attracted some attention, let us as-
sume for a moment, that the coal plants of Melville
Island are strictly analogous to those of the strata of
Northumberland — would such a fact present an inex-
plicable enigma to the vegetable physiologist ?

Plants, it is affirmed, cannot remain in darkness,
even for a week, without serious injury, unless in 2
torpid state; and if exposed to heat and moisture they
cannot remain torpid, but will grow, and must there-
fore perish. If, then, in the latitude of Melville Island,
75° N., a high temperature, and consequent humidity,
prevailed at that period when we know the arctic seas
were filled with corals and large multilocular shells,
how could plants of tropical forms have flourished ?
Is not the bright light of equatorial regions as indis-
pensable a condition of their well-being as the sultry
heat of the same countries? and how could they an-
nually endure a night prolonged for three months ? *

Now, in reply to this objection, we must bear in
mind, in the first place, that, so far as experiments
have been made, there is every reason to conclude,
that the range of intensity of light to which living
plants can accommodate themselves is far wider than
that of heat. No palms or tree ferns can live in our
temperate latitudes without protection from the cold;
but when placed ‘in hot-houses they grow luxuriantly,
even under a cloudy sky, and where much light is in-
tercepted by the glass and frame-work. At St. Peters-
burg, in lat. 60° N., these plants have been success-
fully cultivated in hot-houses, although there they

* Fossil Flora, No. IV.

Ch. VIJ CHANGE OF CLIMATE, 161

must exchange the perpetual equinox of their native
regions for days and nights which are alternately pro-
tracted to nineteen hours and shortened to five. How
much farther towards the pole they might continue to
live, provided a due quantity of heat and moisture were
Supplied, has not yet been determined ; but St. Peters-
burg is probably not the utmost limit, and we should
expect that in Jat. 65° at least, where they would never
remain twenty-four hours without enjoying the sun’s
light, they might still exist.

Nor must we forget that we are here speaking of
living species formed to inhabit within or near the
tropics. But the coal plants were of perfectly distinct
Species, and may have been endowed with a different
Constitution, enabling them to bear a greater variation
of circumstances in regard to light. We find that par-
ticular species of palms and tree ferns require at pre-
Sent different degrees of heat ; and that some species
Can thrive only in the immediate neighbourhood of
the equator, others only at a distance from it. In the
Same manner the minimum of light, sufficient for the
how existing species, cannot be taken as the standard
for all analogous tribes that may ever have flourished
on the globe.

But granting that the extreme northern point to
Which a flora like that of the carboniferous era could
“ver reach may be somewhere between the latitudes
of 65° and 70°, we should still have to inquire whether
the vegetable remains might not have been drifted
from thence, by rivers and currents, to the parallel of
Melville Island, or still farther. Inthe northern hemi-
Sphere, at present, we see that the materials for future
beds of lignite and coal are becoming amassed in high
latitudes, far from the districts where the forests grew,

162 ` ʻE FOSSIL PLANTS, [Book I.

and on shores where scarcely a stunted shrub can now
exist. The Mackenzie, and other rivers of North Ame-
rica, carry pines with their roots attached for many
hundred miles towards the north, into the arctic sea
where they are imbedded in deltas, and some of them
drifted still farther by currents towards the pole.

Some of the appearances of our English coal fields
Seem to prove that the plants were not floated from
great distances; for the outline of the stems of succu-
lent species preserve their sharp angles, and others
have their surfaces marked with the most delicate lines
and streaks. Long leaves, also, are attached in many
instances to the trunks or branches*; and leaves we
know, in general, are soon destroyed when steeped in
water, although ferns will retain their forms after an
immersion of several months.t It seems fair to pre-
sume that the coal plants may have grown upon the
same land, the destruction of which provided materials
for the sandstones and conglomerates of the group of
strata in which they are imbedded; especially as the
coarseness of the particles of many of these rocks
attests that they were not borne from very remoté
localities.

Before we are entitled to enlarge farther on this
question of transportation, we must obtain more precise
information respecting the state of the various fossils
which have been found principally in the coal sand-
stones of high latitudes, and we must learn whether `
they bear the marks of friction and decay previous to
their fossilization.

To return, therefore, from this digression, the un-

* Fossil Flora, No. X.
t This has been proved by Mr. Lindley’s experiments.

Ch. VLJ CHANGE OF CLIMATE. 163

injured corals and chambered univalves of Igloolik
(lat. 694° N.), Melville Island, and other high latitudes,
sufficiently prove that, during the carboniferous period,
there was an elevated temperature even in northern.
regions bordering on the arctic circle. The heat and
humidity of the air, and the uniformity of climate,
appear to have been most remarkable when the oldest
strata hitherto discovered were formed. The approx-
imation to a climate similar to that now enjoyed in
these latitudes does not commence till the era of the
formations termed tertiary ; and while the different
tertiary rocks were deposited in succession, the tem-
perature seems to have been still further lowered, and
to have continued to diminish gradually, even after the
appearance upon the earth of a great portion of the
existing species.

CHAPTER VII.

FARTHER EXAMINATION OF THE QUESTION AS TO THE
DISCORDANCE OF THE ANCIENT AND MODERN CAUSES
OF CHANGE.

On the causes of vicissitudes in climate — Remarks on the present
diffusion of heat over the globe — On the dependence of the
mean temperature on the relative position of land and sea—
Isothermal lines— Currents from equatorial regions (p. 170. )—
Drifting of icebergs— Different temperature of Northern and
Southern hemispheres— Combination of causes which might
produce the extreme cold of which the earth’s surface is sus-
ceptible (p. 186.)— Conditions necessary for the production
of the extreme of heat, and its probable effects on organic life
(p. 194.).

Causes of vicissitudes in Climate.— As the proofs
enumerated in the last chapter indicate that the earth’s
surface has experienced great changes of climate since
the deposition of the older sedimentary strata, we
have next to inquire, how such vicissitudes can be re-
conciled with the existing order of nature. The cos-
" mogonist has availed himself of this, as of every obscure
problem in geology, to confirm his views concerning a
period when the laws of the animate and inanimate
world differed essentially from those now established ;
and he has in this, as in many other cases, succeeded
so far, as to divert attention from that class of facts,
which, if fully understood, might probably lead to an
explanation of the phenomena. At first it was ima-
gined that the earth’s axis had been for ages perpen-
dicular to the plane of the ecliptic, so that there was a

Ch. VILJ CAUSES OF VICISSITUDES IN CLIMATE. 165

Perpetual equinox, and uniformity of seasons throughout
the year ;—- that the planet enjoyed this ‘ paradisiacal
State until the eraof the great flood; but in that cata-
Strophe, whether by the shock of a comet, or some other
Convulsion, it lost its equal poise, and hence the obli-
quity of its axis, and with that the varied seasons of
the temperate zone, and the long nights and days of
the polar circles.

When the progress of astronomical science had
€xploded this theory, it was assumed, that the earth
at its creation was in a state of fluidity, and red hot,
and that ever since that era it had been cooling down,
Contracting its dimensions, and acquiring a solid crust,
—an hypothesis hardly less arbitrary, but more calcu-
lated for lasting popularity, because, by referring the
Mind directly to the beginning of things, it requires no
Support from observation, nor from any ulterior hypo-
thesis. They who are satisfied with this solution are
relieved from all necessity of inquiry into the present
laws which regulate the diffusion of heat over the
Surface ; for, however well these may be ascertained,
they cannot possibly afford a full and exact elucidation
of the internal changes of an embryo world.

But if, instead of forming vague conjectures as to
What might have been the state of the planet at the
era of its creation, we fix our thoughts on the connexion
at present existing between climate and the distri-
bution of land and sea; and then consider what in-

uence former fluctuations in the physical geography
of the earth must have had on superficial temperature,
we may perhaps approximate to a true theory. If
doubts and obscurities still remain, they should be
ascribed to our limited acquaintance with the laws of
ature, not to revolutions in her economy ;— they

166 LAWS GOVERNING THE DIFFUSION OF HEAT. [Book 1.

should stimulate us to further research, not tempt us
to indulge our fancies in framing imaginary systems
for the government of infant worlds.

Diffusion of heat over the globe.—In considering the
laws which regulate the diffusion of heat over the
globe, we must be careful, as Humboldt well remarks,
not to regard the climate of Europe as a type of the
temperature which all countries placed under the same
latitude enjoy. The physical sciences, observes this
philosopher, always bear the impress of the places
where they began to be cultivated ; and as, in geology,
an attempt was at first made to refer all the volcanic
phenomena to those of the volcanos in Italy, so, in
meteorology, a small part of the old world, the centre
of the primitive civilization of Europe, was for a long
time considered a type to which the climate of all
corresponding latitudes might be referred. But this
region, constituting only one seventh of the whole
globe, proved eventually to be the exception to the
general rule. For the same reason, we may warn
the geologist to be on his guard, and not hastily to
assume that the temperature of the earth in the
present era is a type of that which most usually
obtains, since he contemplates far mightier alterations
in the position of land and sea, at different epochs,
than those which now cause the climate of Europe
to differ from that of other countries in the same
parallels.

It is now well ascertained that zones of equal
warmth, both in the atmosphere and in the waters
of the ocean, are neither parallel to the equator nor to
each other.* It is also known that the mean annual

* We are indebted to Baron Alex. Humboldt for collecting
together, in a beautiful essay, the scattered data on which he

Ch. VIL] CAUSES OF CHANGE OF CLIMATE. 167

temperature may be the same in two places which
enjoy very different climates, for the seasons may be
Nearly uniform, or violently contrasted, so that the
lines of equal winter temperature do not coincide
With those of equal annual heat, or isothermal lines.
The deviations of all these lines from the same parallel
of latitude are determined by a multitude of circum-
stances, among the principal of which are the position,
direction, and elevation of the continents and islands,
the position and depths of the sea, and the direction of
Currents and of winds.

On comparing the two continents of Europe and
America, it is found that places in the same latitudes
have sometimes a mean difference of temperature
amounting to 11°, or even in a few cases to 17° Fahr.;
and some places on the two continents, which have the
Same mean temperature, differ from 7° to 13° in lati-
tude.* The principal cause of greater intensity of
Cold in corresponding latitudes of North America and.
Europe, is the connexion of North America with the
Polar circle, by a large tract of land, some of which is
from three to five thousand feet in height, and, on the
other hand, the separation of Europe from the arctic
Circle by an ocean. The ocean has a tendency to
Preserve every where ʻa mean temperature, which it
Communicates to the contiguous land, so that it tempers

the climate, moderating alike an excess of heat or cold.
“ae ee L

founded an approximation to a true theory of the distribution of

heat over the globe. Many of these data are derived from the

author’s own observations, and many from the works of M. Pierre

revost, of Geneva, on the radiation of heat, and other writers. —

ee Humboldt on Isothermal Lines, Memoires d’Arcueil, tom. iii
translated in the Edin. Phil. Journ. vol. iii. July, 1820.
* Humboldt’s tables, Essay on Isothermal Lines, &c.

168 DEPENDENCE OF CLIMATE [Book I

The elevated land, on the other hand, rising to the
colder regions of the atmosphere, becomes a great
reservoir of ice and snow, arrests, condenses, and con-
geals vapour, and communicates its cold to the adjoin-
ing country. For this reason, Greenland, forming part
of a continent which stretches northward to the 82d
degree of latitude, experiences under the 60th parallel
a more rigorous climate than Lapland under the 72d
parallel.

But if land be situated between the 40th parallel
and the equator, it produces, unless it be of extreme
height, exactly the opposite effect; for it then warms
the tracts of land or sea that intervene between it and
the polar circle. For the surface being in this case
exposed to the vertical, or nearly vertical rays of the
sun, absorbs a large quantity of heat, which it diffuses
by radiation into the atmosphere. For this reason, the
western parts of the old continent derive warmth from
Africa, “ which, like an immense furnace, distributes
its heat to Arabia, to Turkey in Asia, and to Europe.”*
On the contrary, the north-eastern extremity of Asia
experiences in the same latitude extreme cold ; for it
has land on the north between the 60th and 70th
parallel, while to the south it is Separated from the
equator by the Indian ocean.

In consequence of the more equal temperature of
the waters of the ocean, the climate of islands and of
coasts differs essentially from that of the interior of
continents, the more maritime climates being charac-
terized by mild winters and more temperate summers ;
for the sea breezes moderate the cold of winter, as
well as the heat of summer, When, therefore, we

* Malte-Brun. Phys. Geog. book xvii.

Ch. VIL] ON POSITION OF LAND: AND SEA. 169

trace round the globe those belts in which the mean
annual temperature is the same, we often find great
differences in climate ; for there are insular climates
in which the seasons are nearly equalized, and exces-
sive climates, as they have been termed, where the
temperature of winter and summer is strongly con-
trasted. The whole of Europe, compared with the
€astern parts of America and Asia, has an insular
Climate. The northern part of China, and the Atlantic
Tegion of the United States, exhibit “excessive cli-
Mates.” We find at New York, says Humboldt, the
Summer of Rome and the winter of Copenhagen; at
Quebec, the summer of Paris and the winter of Peters-
burg. At Pekin, in China, where the mean temper-
ature of the year is that of the coasts of Brittany, the
Scorching heats of summer are greater than at Cairo,
and the winters as rigorous as at Upsala.*

If lines be drawn round the globe through all those
Places which have the same winter temperature, they
are found to deviate from the terrestrial parallels much
farther than the lines of equal mean annual heat. The
lines of equal winter in Europe, for example, are often
Curved so as to reach parallels of latitude 9° or 10°
distant from each other, whereas the isothermal lines,
Or those passing through places having the same mean
annual temperature, differ only from 4° to 5°.

Influence of currents and drift ice on temperature. — |
Among other influential causes, both of remarkable

versity in the mean annual heat, and of unequal divi-
Son of heat in the different seasons, are the direction
of Currents and the accumulation and drifting of ice
M high latitudes. The temperature of the Lagullas

j

* On Isothermal Lines, &c.
VOL. I. I

170 GULF STREAM. [Book £.

current is 10° or 12° Fahr. above that of the sea at
the Cape of Good Hope; for the greater part of its
waters flow through the Mozambique channel, dow?
the south-east coast of Africa, and are derived from
regions in the Indian Ocean much nearer the line, and
much hotter than the Cape.* An opposite effect is
produced by the “equatorial” current, which crosses
the Atlantic from Africa to Brazil, having a breadth
varying from 160 to 450 nautical miles. Its waters
are cooler by 3° or 4° Fahr. than those of the ocean
under the line, so that it moderates the heat of the
tropics.+

But the effects of the Gulf stream on the climate
of the north Atlantic Ocean are far more remark-
able. This most powerful of known currents has its
source in the Gulf or Sea of Mexico, which, like the
Mediterranean and other close seas in temperate oF
low latitudes, is warmer than the open ocean in the
same parallels. The temperature of the Mexican sea
in summer is, according to Rennell, 86° Fahr. of
at least 7° above that of the Atlantic in the same
latitude.{ From this great reservoir or caldron of
warm water, a constant current pours forth through
the straits of Bahama at the rate of 3 or 4 miles ar
hour ; it crosses the ocean in a north-easterly direc-
tion, skirting the great bank of Newfoundland, where
it still retains a temperature of 8° above that of the
surrounding sea. It reaches the Azores in about 78
days, after flowing nearly 3000 geographical miles,
and from thence it sometimes extends its course #
thousand miles further, so as to reach the Bay of Bis-
cay, still retaining an excess of 5° above the mea?

* Rennell on Currents, p. 96. London, 1832.

+ Ibid. p. 153. t Ibid. p. 25.

Ch. VIL] INFLUENCE OF CURRENTS ON TEMPERATURE. 171

temperature of that sea. As it has been known to
arrive there in the months of November and January,
it may tend greatly to moderate the cold of winter in
countries on the west of Europe.

There is a large tract in the centre of the North
_ Atlantic, between the parallels of 33° and 35° N. lat.
which Rennell calls the “ recipient of the gulf water.”
A great part of it is covered by the weed called sar-
gasso, which the current floats in abundance from the
Gulf of Mexico. This mass of water is nearly stag-
Nant, is warmer by 7° or 10° than the waters of the
Atlantic, and may be compared to the fresh water of
a river overflowing the heavier salt water of the sea.
Rennell estimates the area of the “recipient,” together
With that covered by the main current, as being 2000
Miles in length from E. to W., and 350 in breadth
from N. to S., which, he remarks, is a larger area than
that of the Mediterranean. The heat of this great
body of water is kept up by the incessant and quick
arrival of fresh supplies of warm water from the south,
and there can be no doubt that the general climate of
parts of Europe and America are materially affected.
by this cause.

It is considered probable by Scoresby, that the in-
fluence of the gulf stream extends even to the sea near
Spitzbergen, where its waters may pass under those of
Melted ice; for it has been found that, in the neigh-
bourhood of Spitzbergen, the water is warmer by 6°
or 7° at the depth of one hundred and two hundred
fathoms than at the surface. This might arise from
the known law that fresh water passes the point of
greatest density when cooled down below 40°, and
between that and the freezing point expands again.
The water of melted ice might be lighter, both as

12

172 INFLUENCE OF CURRENTS ON TEMPERATURE. [Book E
[

being fresh (having lost its salt in the decomposing
process of freezing), and because its temperature is
nearer the freezing point than the inferior water of the
gulf stream.*

The great glaciers generated in the valleys of Spitz-
bergen, in the 79° of north latitude, are almost all cut
off at the beach, being melted by the feeble remnant
of heat still retained by the gulf stream. In Baffin’s
Bay, on the contrary, on the west coast of Old Green-
land, where the temperature of the sea is not mitigated
by the same cause, and where there is no warmer
under-current, the glaciers stretch out from the shore,
and furnish repeated crops of mountainous masses of
ice which float off into the ocean.t The number and
dimensions of these bergs is prodigious. Captain Ross
saw several of them together in Baffin’s Bay aground
in water fifteen hundred feet deep! Many of them

are driven down into Hudson’s Bay, and accumulating
there, diffuse excessive cold over the neighbouring
continent; so that Captain Franklin reports, that at
‘the mouth of Hayes river, which lies in the same

* When Scoresby wrote in 1820 (Arctic Regions, vol. i.
p. 210.), he doubted whether salt water expanded like fresh
water when freezing. Since that time Erman (Poggendorf’s
Annaler, 1828, vol. xii. p. 483.) has proved by experiment that
sea-water does not follow the same law as fresh water, as De
Luc, Rumford, and Mareet had supposed. On the contrary,
it appears that salt water of sp. gr. 1-027 (which according to
Berzelius is the mean density of sea water) has no maximum
of density so long as it remains fluid; and even when ice begins to
form in it, the remaining fluid part always increases in density in
proportion to the degree of refrigeration.

+ Scoresby’s Arctic Regions, vol. i. p. 208.—Dr. Latta’s Ob-
servations on the Glaciers of Spitzbergen, &c. Edin. New Phil.
Journ, vol, iil. p. 97.

Ch. VIL] ' CHANGE OF CLIMATE. 173

latitude as the north of Prussia or the south of Scot-
land, ice is found every where in cigging wells, in
summer, at the depth of four feet! Other bergs have
been occasionally met with, at midsummer, in a state
of rapid thaw, as far south as lat. 40°, and longitude
about 60° West, where they cool the water sensibly to
the distance of forty or fifty miles around, the ther-
Mometer sinking sometimes 17°, or even 18°, Fahren-
heit, in their neighbourhood.* It is a well-known fact
that every four or five years a large number of icebergs,
floating from Greenland, double Cape Langaness, and
are stranded on the west coast of Iceland. The inha-
bitants are then aware that their crops will fail, in con-
Sequence of fogs which are generated almost inces-
Santly ; and the dearth of food is not confined to the
land, for the temperature of the water is so changed
that the fish entirely desert the coast.

Difference of climate of the Northern and Southern
hemispheres. — When we compare the climate of the
Northern and southern hemispheres, we obtain still
More instruction in regard to the influence of the dis-
tribution of land and seaon climate. The dry land in
the southern hemisphere is to that of the northern in
the ratio only of one to three, excluding from our con-
Sideration that part which lies between the pole and
the 74° of south latitude, which has hitherto proved
inaccessible. And whereas, in the northern hemi-
Sphere, between the pole and the thirtieth parallel of
North latitude, the land and sea occupy nearly equal
areas, the ocean in the southern hemisphere covers no
less than fifteen parts in sixteen of the entire space
included between the antarctic circle and the thirtieth
Parallel of south latitude.

* Rennell on Currents, p. 95.

LG

174 DIFFERENCE OF CLIMATE IN NORTHERN [Book].

This great extent of sea gives a particular character
to climates south of the equator, the winters being
mild and the summers cool. Thus, in Van Diemen’s
Land, corresponding nearly in latitude to Rome, the
winters are more mild than at Naples, and the summers
not warmer than those at Paris, which is 7° farther
from the equator.* The effect on vegetation is very
remarkable :—tree-ferns, for instance, which require
abundance of moisture, and an equalization of the
seasons, are found in Van Diemen’s Land, in latitude
49° S.; and in New Zealand in south latitude 45°.
The orchideous parasites also advance to the 38° and
42° of south latitude. Humboldt observes that it is in the
mountainous, temperate, humid, and shady parts of the
equatorial regions, that the family of ferns produces the
greatest number of species. As we know, therefore,
that elevation often compensates for the effect of
latitude in the geographical distribution of plants, we
may easily understand that a class of vegetables,
which grow ata certain height in the torrid zone,
would flourish on the plains at greater distances from
the equator, if the temperature, moisture, and other
necessary conditions, were equally uniform through-
out the year.

It has long been supposed that the general tem-
perature of the southern hemisphere was considerably
lower than that of the northern, and that the difference
amounted to at least 10° Fahrenheit. Baron Hum-
boldt, after collecting and comparing a great number
of observations, came to the conclusion that even 2
much larger difference existed, but that none was to
be observed within the tropics, and only a small

* Humboldt on Isothermal Lines.

Ch. VIL] AND SOUTHERN HEMISPHERES. 175

difference as far as the thirty-fifth and fortieth parallel.
Captain Cook was of opinion that the ice of the ant-
arctic predominated greatly over that of the arctic
region, that encircling the southern pole coming nearer
to the equator by 10° than the ice around the north
pole. But the recent voyages of Weddell and Biscoe
have shewn that on certain meridians it is possible to
approach the south pole nearer by several degrees than
Cook had penetrated ; and even in the seventy-third and
Seventy-fourth degrees of south latitude, they found the
Sea open and with few ice-floes.*

Nevertheless, the greater cold of high southern
latitudes is confirmed by the description given both by
ancient and modern navigators of the lands in this
hemisphere. In Sandwich land, according to Cook,
in 59° of south latitude, the perpetual snow and ice
reach to the sea beach ; and what is still more astonish-

ing, in the island of Georgia, which is in the 54° south
latitude, or the same parallel as Yorkshire, the line of
perpetual snow descends to the level of the ocean.
When we consider this fact, and then recollect that
the summit of the highest mountains in Scotland,
four degrees farther to the north, do not attain the

* Captain Weddell, in 1823, advanced 3° farther than Captain
Cook, and arrived at lat. 74° 15! south, long. 34° 17’ west. After
having passed through a sea strewed with numerous ice islands, he
arrived, in that high latitude, at an open ocean; but even if he
had sailed 6° farther south, he would not have penetrated to higher
latitudes than Captain Parry in the arctic circle, who reached
lat. 81° 19’ 51” north. Captain Biscoe, in 1831 and 1832, dis-
covered Graham’s Land, between 64° and 68° S. lat., to the south-
ward of New South Shetland, and Enderby’s Land, in the same
latitude, on the meridian of Madagascar. Journ. of Roy. Geo-
graph. Soc. of London, 1833, p. 105.

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176 DIFFERENCE OF CLIMATE IN NORTHERN [Book L

limit of perpetual snow on our side of the equator, we
learn that latitude is one only of many powerful
causes, which determine the climate of particular
regions of the globe. The permanence of snow in
the southern hemisphere, is in this instance partly due
to the floating ice, which chills the atmosphere and
condenses the vapour, so that in summer the sun
cannot pierce through the foggy air. But besides the
abundance of ice which covers the sea to the south
of Georgia and Sandwich land, we may also, as Hum-
boldt suggests, ascribe the cold of those countries in
part to the absence of land between them and the
tropics. ;

If Africa and New Holland extended farther to the
south, a diminution of ice would take place in conse-
quence of the radiation of heat from these continents
during summer, which would warm the contiguous sea
and rarefy the air. The heated aërial currents would
then ascend and flow more rapidly towards the south
pole, and moderate the winter. In -confirmation of
these views, it is stated that the ice, which extends
as far as the 68° and 71° of south latitude, advances
more towards the equator whenever it meets an open
sea ; that is, where the extremities of the present
continents are not opposite to it; and this circum-
stance seems explicable only on the principle above
alluded to, of the radiation of heat from the lands so
situated.

The cold of the antarctic regions was conjectured by
Cook to be due to the existence of a large tract of
land between the seventieth degree of south latitude —
and the pole ; and it is worthy of observation, that
even now, after the most recent voyages, the area
still unexplored within the antarctic circle is much

Ch, VIL] AND SOUTHERN HEMISPHERES. 177

more than double the area of Europe.* Some geo-
graphers think that the late discovery of Graham’s*and
Enderby’s Lands (between lat. 64° and 68° S.), both
of which Captain Biscoe believes to be of great ex-
tent, has strengthened the probability of Cook’s con-
jecture. These newly observed countries, although
placed in latitudes in which herds of wild herbivorous
animals are met with in the northern hemisphere, nay,
where man himself exists, and where there are ports
and villages, are described as most wintery in their
aspect, almost entirely covered, even in summer, with
ice and snow, and nearly destitute of animal life.

The distance to which icebergs float from the polar
regions on the opposite sides of the line is, as might
have been anticipated, very different. Their extreme
limit in the northern hemisphere is lat. 40°, as before
mentioned, and they are occasionally seen in lat. 42° N.
Near the termination of the great bank of Newfound-
land, and at the Azores, lat. 42° N., to which they are
Sometimes drifted from Baffin’s Bay. But in the other
hemisphere they have been seen, within the last few
Years, at different points off the Cape of Good Hope,
between latitude 36° and 39°.+ One of these (see fig. 3.)
Was two miles in circumference, and 150 feet high,
appearing like chalk when the sun was obscured, and
having the lustre of refined sugar when the sun was
shining on it. Others rose from 250 to 300 feet above
the level of the sea, and were therefore of great
Volume below ; since it is ascertained, by experiments

T Mr. Gardner informs me that the surface of Europe con-
tains about 2,793,000 square geographical miles, the unexplored
antarctic region about 7,620,000.
=t On Icebergs in low Latitudes, by Capt. Horsburgh, by

Whom the sketch was made, Phil. Trans. 1830.

145

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CAUSES OF

Iceberg seen off the Cape of Good Hope, April 1829.
Lat. 39° 13 S. Long. 48° 46’ E.

on the buoyancy of ice floating in sea-water, that for
every solid foot seen above, there must at least be
eight cubic feet below water.* If ice islands from the
north polar regions floated as far, they might reach
Cape St. Vincent, and there, being drawn by the cur-
rent that always sets in from the Atlantic through the
Straits of Gibraltar, be drifted into the Mediterranean,
so that the serene sky of that delightful region might
soon be deformed by clouds and mists.

Before the amount of difference between the tem-
perature of the two hemispheres was ascertained, it
was referred by many astronomers to the precession of
the equinoxes, or the acceleration of the earth’s motion
in its perihelium; in consequence of which the spring
andsummer of the southern hemisphere are now shorter;
by nearly eight days, than those seasons north of the
equator. But Sir J. Herschel reminds us that the ex-
cess of eight days in the duration of the sun’s presence
in the northern hemisphere ‘is not productive of aD
excess of annual light and heat; since, according to the
laws of elliptic motion, it is demonstrable that what-
ever be the ellipticity of the earth’s orbit, the tw?

* Scoresby’s Arctic Regions, vol. i. p. 234.

Ch, VILJ CHANGES OF TEMPERATURE. 179

hemispheres must receive equal absolute quantities of
light and heat per annum, the proximity of the sun in
perigee exactly compensating the effect of its swifter
motion.* Humboldt, however, observes, that there
must be a greater loss of heat by radiation in the
southern hemisphere during a winter longer by eight
days than that on the other side of the equator.+:

Perhaps no very sensible effect may be produced by
this source of disturbance, yet the geologist should bear
in mind that to a certain extent it operates alternately
on each of the two hemispheres for a period of upwards
of 10,000 years, dividing unequally the times during
which the annual supply of solar light and heat is
received. This cause may sometimes tend to counter-
balance inequalities of temperature resulting from other
far more influential circumstances ; but, on the other
hand, it must sometimes tend to increase the extreme
of deviation arising from particular combinations of
Causes.

But whatever may be at present the inferiority of
heat in the temperate and frigid zones south of the
line, it is quite evident that the cold-would be far more
intense if there happened, instead of open sea, to be
tracts of elevated land between the 55th and 70th
parallel; and on the other hand, the cold would be

* This follows, observes Herschel, from a very simple theorem,
which may be thus stated: —‘‘ The amount of heat received by
the earth from the sun, while describing any part of its orbit, is
Proportional to the angle described round the sun’s centre.” So
that if the orbit be divided into two portions by a line drawn in
any direction through the sur’s centre, the heat received in de-
scribing the two unequal segments of the ellipse so produced will
be equal. Geol. Trans. vol. iii. part ii. p. 298.5 second series.

+ On Isothermal Lines.

16

180 <CAUSES OF [Book I.

moderated if there was more land between the line
and the forty-fifth degree of south latitude.

Changes in the position of land and sea may give rise
to vicissitudes in climate.— Having offered these brief
remarks on the diffusion of heat over the globe in the
present state of the surface, I shall now proceed to
speculate on the vicissitudes of climate, which must
attend those endless variations in the geographical
features of our planet which are contemplated in geo-
logy. That our speculations may be confined within
the strict limits of analogy, I shall assume, Ist, That
the proportion of dry land to sea continues always the
same. 2dly, That the volume of the land rising above
the level of the sea is a constant quantity ; and not
only that its mean, but that its extreme height, are
liable only to trifling variations. 3dly, That both the
mean and extreme depth of the sea are invariable;
and, 4thly, It may be consistent with due caution to
assume that the grouping together of the land in great
continents is a necessary part of the economy of
nature ; for it is possible that the laws which govern
the subterranean forces, and which act simultaneously
along certain lines, cannot but produce, at every epoch,
continuous mountain-chains; so that the subdivision
of the whole land into innumerable islands may be
precluded.

Af it be objected, that the maximum of elevation of
land and depth of. sea are probably not constant, nor
the gathering together of all the land in certain parts,
nor even perhaps the relative extent of land and water,
I reply, that the arguments about to be adduced will
be strengthened, if, in these peculiarities of the sur-
face, there be considerable deviations from the present
type. If, for example, all other circumstances being

Ch. VIL] CHANGES OF TEMPERATURE. 181

the same, the land is at one time more divided into
islands than at another, a greater uniformity of climate
might be produced, the mean temperature remaining
unaltered ; or if, at another era, there were mountains
higher than ‘the Himalaya, these, when placed in high
latitudes, would cause a greater excess of cold. Or, if
We suppose that at certain periods no chain of hills in the
world rose beyond the height of 10,000 feet, a greater
heat might then have prevailed than is compatible
With the existence of mountains thrice that elevation.

However constant may be the relative proportion of
sea and land, we know that there is annually some
small variation in their respective geographical posi-
tions, and that in every century the land is in some
parts raised, and in others depressed by earthquakes ;
and so likewise is the bed of the sea. By these and
other ceaseless changes, the configuration of the
earth’s surface has been remodelled again and again
since it was the habitation of organic beings, and the
bed of the ocean has been lifted up to the height of
some of the loftiest mountains. The imagination is
apt to take alarm when called upon to admit the form-
ation of such irregularities in the crust of the earth,
after it had once become the habitation of living crea-
tures ; but, if time be allowed, the operation need not
subvert the ordinary repose of nature, and the result
is in a general view insignificant if we consider how
slightly the highest mountain-chains cause our globe
to differ from a perfect sphere. Chimborazo, though
it rises to more than 21,000 feet above the sea, would
be represented, ona globe of about six feet in diameter,
by a grain of sand less than one-twentieth of an inch
in thickness.*

* Malte-Brun’s System of Geography, book i. p. 6.

182 CAUSES OF [Book 1.

The superficial inequalities of the earth, then, may
be deemed minute in quantity, and their distribution
at any particular epoch must be regarded in geology
as temporary peculiarities, like the height and outline
of the cone of Vesuvius in the interval between two
eruptions. But although, in reference to the mag-
nitude of the globe, the unevenness of the surface is s0
unimportant, it is on the position and direction of these
small inequalities that the state of the atmosphere,
and both the local and general climate, are mainly
dependent.

Before considering the effect which a material
change in the distribution of land and sea must occa-
sion, it may be well to remark, how greatly organic
life may be affected by those minor variations, which
need not in the least degree alter the general tem-
perature. Thus, for example, if we suppose, by a
series of convulsion, a certain part of Greenland to
become sea, and, in compensation, a tract of land to
rise and connect Spitzbergen with Lapland, —an ac-
cession not greater in amount than one which the
geologist can prove to have occurred in certain dis-
tricts bordering the Mediterranean, within a com-
paratively modern period,—this altered form of the
land might cause an interchange between the climate
of certain, parts of North America and of Europe,
which lie in corresponding latitudes, Many European
species of plants.and animals would probably perish in
consequence, because the mean temperature would be
greatly lowered ; and others would fail in America,
because it would there be raised. On the other hand,
in places where the mean annual heat remained un-
altered, some species which flourish in Europe, where
the seasons are more uniform, would be unable to resist

Ch, VIL] CHANGES OF TEMPERATURE. 183

the greater heat of the North American summer, Or
the intenser cold of the winter ; while others, now
fitted by their habits for the great contrast of the
American seasons, would not be fitted for the insular
climate of Europe. The vine, for example, according
to Humboldt, can be cultivated with advantage 10°
farther north in Europe than in North America. Many
plants endure severe frost, but cannot ripen their
seeds without a certain intensity of summer heat and
a certain quantity of light ; others cannot endure a
similar intensity either of heat or cold.

It ig now established that many of the existing
Species of animals have survived great changes in the
physical geography of the globe. If such species be
termed modern, in comparison to races which pre-
ceded them, their remains, nevertheless, enter into
submarine deposits many hundred miles in length,
and which have since been raised from the deep to no
inconsiderable altitude. When, therefore, it is shown
that changes in the temperature of the atmosphere
may be the consequence of such physical revolutions
of the surface, we ought no longer to wonder that we
find the distribution of existing species to be local, in
regard to longitude as well as latitude. If all species
were now, by an exertion of creative power, to be
diffused uniformly throughout those zones where there
is an equal degree of heat, and in all respects a simi-
larity of climate, they would begin from this moment
to depart more and more from their original distribu-
tion. Aquatic and terrestrial species would be dis-
placed, as Hooke long ago observed, ‘so often as land
and water exchanged places ; and there would also, by
the formation of new mountains and other changes, be

SS pee o anan

184 CAUSES OF or [Book L

transpositions of climate, contributing, in the manner
before alluded to, to the local extermination of species.*

If we now proceed to consider the circumstances
required for a general change of temperature, it will
appear, from the facts and principles already laid down,
that whenever a greater extent of high land is col-
lected in the polar regions, the cold will augment; and ~
the same result will be produced when there is more
sea between or near the tropics ; while, on the con-
trary, so often as the above conditions are reversed,
the heat will be greater. (See Map, Pl. 1.) - If; this
be admitted, it will follow, that unless the superficial
inequalities of the earth be fixed and permanent, there
must be never-ending fluctuations in the mean tem-
perature of every zone ; and that the climate of one
era can no more be a type of every other, than is one
of our four seasons of all the rest.

It has been well said, that the earth is covered by
an ocean, in the midst of which are two great islands,
and many smaller ones; for the whole of the conti-
nents and islands occupy an area scarcely exceeding
one fourth of the whole superficies of the spheroid.
Now, on a fair estimate of probability, we may rea-
sonably assume that there will not, at any given epoch,
be more than about one fourth dry land in a particular
region; such, for example, as within the arctic and
antarctic circles. If, therefore, at present there should
happen, in the only one of these regions which we can
explore, to be much more than this average proportion
of land, and some of it above five thousand feet in
height, this alone affords ground for concluding that,

* A full consideration of the effect of changes in physical geo-

‘graphy on the distribution and extinction of species, is given in

book iii.

Ch. VIL] ° CHANGES OF TEMPERATURE. 185

inthe present state of things, the mean heat of the
Climate is below that which the earth’s surface, in its
More ordinary state, would enjoy. This presumption
Would be heightened, were we to assume that the
Mean depth of the Atlantic and Pacific oceans is as
great as some astronomers have imagined *; for then
Wwe might look not only for more than two thirds sea
in the frigid zones, but for water of great depth, which
Could not readily be reduced to the freezing point.
The same opinion is confirmed, when we compare the
quantity of land lying between the poles and the 30th
Parallels of north and south latitude, with the quantity
Placed between those parallels and the equator ; for, it
18 clear, that we have at present not only more than
the usual degree of cold in the polar regions, but also

* See Young’s Nat. Phil. Lect. xlvii.; Mrs. Somerville’s Con-

nex, of Phys. Sci. sect. 14. p. 110. Laplace, endeavouring to
estimate the probable depth of the sea from some of the phenomena
Of the tides, says of the ocean generally, ‘que sa profondeur mo-
Yenne est du même ordre que la hauteur moyenne des continens et
des isles au-dessus de son niveau, hauteur qui ne surpasse pas mille
mètres (3280 ft.).” Mec. Céleste, Bk. xi. et Syst. du Monde,
P. 254. The expression “du même ordre” admits in mathe-
matical language, of considerable latitude of signification, and does
Not mean that the depth of the water below the level of the sea
Corresponds exactly to the height of the land above it. I have
endeavoured, in vain, after consulting several eminent mathema-
Ucians, among others, Professor Airy, Mr. Lubbock, and Mr.
Whewell, to arrive at some conclusion as to the absolute depth of
the ocean. My informants all agree in declaring that the hypo-
thetical data on which the calculations of Laplace necessarily
Proceeded cannot give even an approximation to a solution of the
Problem. Neither does Mr. Whewell believe in the alleged ap-
Proach to uniformity in the depth of the ocean, which some have
Wished to deduce from the supposed smallness of the difference of
the two tides occurring on the same day. (London, March, 1835.)

186 CAUSES OF [Book I.

less than the average quantity of heat within the
tropics.

Position of land and sea which might produce the
extreme of cold of which the earth’s surface is susceptible.
— To simplify our view of the various changes in cli-
mate, which different combinations of geographical
circumstances may produce, we shall first consider
the conditions necessary for bringing about the ex-
treme of cold, or what may be termed the winter of
the “great year,” or geological cycle, and afterwards,
the conditions requisite to produce the maximum of
heat, or the summer of the same year.

To begin with the northern hemisphere. Let us
suppose those hills of the Italian peninsula and of
Sicily, which are of comparatively modern origin, and
contain many fossil shells identical with living species,
to subside again into the sea, from which they have
been raised, and that an extent of land of equal erea
and height (varying from one to three thousand feet)
should rise up in the Arctic Ocean between Siberia
and the north pole. In speaking of such changes, I
shall not allude to the manner in which I conceive it
possible that they may be brought about, nor of the
time required for their accomplishment — reserving
for a future occasion, not only the proofs that revolu-
tions of equal magnitude have taken place, but that
analogous operations are still in gradual progress. The ©
alteration now supposed in the physical geography of
the northern regions would cause additional snow and
ice to accumulate where now there is usually an open
sea; and the temperature of the greater part of
Europe would be somewhat lowered, so as to resemble
more nearly that of corresponding latitudes of North
America: or, in other words, it might be necessary t0

Ch. VIL] CHANGES OF TEMPERATURE. 187

travel about 10° farther south ‘in order to meet with
the same climate which we now enjoy. No compens-
ation would be derived from the disappearance of land
in the Mediterranean countries; but the contrary,
since the mean heat of the soil in those latitudes is
Probably far above that which would belong to the
sea, by which we imagine it to be replaced.

But let the configuration of the surface be still fur-
ther varied, and let some large district within or near
the tropics, such as Mexico, with its mountains rising
to the height of twelve thousand feet and upwards, be
converted into sea, while lands of equal elevation and
extent rise up in the arctic circle. From this change
there would, in the first place, result a sensible dimi-
Nution of temperature near the tropic, for the soil of
Mexico would no longer be heated by the sun; so
that the atmosphere would be less warm, as also the
neighbouring Atlantic. On the other hand, the whole
of Europe, Northern Asia, and North America, would
be chilled by the enormous quantity of ice and snow,
thus generated at vast heights on the new arctic con-
tinent. If, as we have already seen, there are now
Some points in the southern hemisphere where snow
1s perpetual down to the level of the sea, in latitudes
as low as central England, such might assuredly be
the case throughout a great part of Europe, under the
change of circumstances above supposed; and if at
Present the extreme range of drifted icebergs is the
Azores, they might easily reach the equator after the
assumed alteration. But to pursue the subject still
- farther, let the Himalaya mountains, with the whole
of Hindostan, sink down, and their place be occupied
by the Indian ocean, while an equal extent of territory
and mountains, of the same vast height, rise UP be-

~ - = = ae a Se
Si SS eee — -ees ————— a = Se = —
SS ae iat = SS

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188 ' CAUSES OF `i [Book 1.

tween North Greenland and the Orkney islands. It
seems difficult to exaggerate the amount to which the
climate of the northern hemisphere would then be
cooled,

But the refrigeration brought about at the same
time in the southern hemisphere, would be nearly equal,
and the difference of temperature between the arctic
and equatorial latitudes would not be much greater
than at present; for no important disturbance can
occur in the climate of a particular region, without its
immediately affecting all other latitudes, however re-
mote. The heat and cold which surround the globe
are in a state of constant and universal flux and reflux.
The heated and rarefied air is always rising and flowing
from the equator towards the poles in the higher
regions of the atmosphere ; while in the lower, the
colder air is flowing back to restore the equilibrium.
That this circulation is constantly going on in the
aérial currents is not disputed ; it is often proved by
the opposite course of the clouds at different heights,
and the fact was farther illustrated in a striking man-
ner by an event which happened during the present
century. The trade wind continually blows with great
force from the island of Barbadoes to that of St. Vin-
cent; notwithstanding which, during the eruption of
the volcano in the island of St. Vincent, in 1812, ashes
fell in profusion from a great height in the atmosphere
upon Barbadoes. This apparent transportation of
matter against the wind, confirmed the opinion of the
existence of a counter-current in the higher regions,
which had previously rested on theoretical conclusions
only. *

* Daniell’s Meteorological Essays, p. 103.

Ch. VIL] CHANGES OF TEMPERATURE. 189

That a corresponding interchange takes place in
the seas, is demonstrated, according to Humboldt, by
the cold which is found to exist at great depths be-
tween the tropics ; and, among other proofs, may be
Mentioned the mass of warmer water which the Gulf
Stream is constantly bearing northwards, while a cooler
Current flows from the nor th along the coast of Green-
land and Labrador, and helps to restore the equili-
brium. *

Currents of heavier and colder water pass from the
Poles towards the equator, which cool the inferior
Parts of the ocean + ; so that the heat of the torrid zone
and the cold of the polar circle balance each other.
The refrigeration, therefore, of the polar regions, re-
Sulting from the supposed alteration in the distribution
of land and sea, would be immediately communicated
to the tropics, and from them ‘its influence would
€xtend to the antarctic circle, where the atmosphere
and the ocean would be cooled, so that ice and snow
Would augment. Although the mean temperature of
higher latitudes in the southern hemisphere is, as
before stated, for the most part lower than that of the
Same parallels in the northern, yet, for a considerable
Space on each side of the line, the mean annual heat
of the waters is found to be the same in corresponding
Parallels. If, therefore, by the new position of the

In speaking of the circulation of air and water in this chapter,
no allusion is made to the trade winds, or to irregularities in the
direction of currents, caused by the rotatory motion of the earth.
These causes prevent the movements from being direct from north
to south, or from south to north, but they do not affect the hary,
of a constant circulation.

t See note, p. 172., on the increasing density of sea-water in
Proportion to the degree of cold.

Sh ee

menpean

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190 CAUSES OF [Book I.

land, the formation of icebergs had become of common
occurrence in the northern temperate zone, and if
these were frequently drifted as far as the equator,
the same degree of cold which they generated would
immediately be communicated as far as the tropic of
Capricorn, and from thence to the lands or ocean tO
the south.

The freedom, then, of the circulation of heat and
cold from pole to pole being duly considered, it will
be evident that the mean temperature which may pre-
vail at the same point at two distinct periods, may
differ far more widely than that of any two points in the
same parallels of latitude, at one and the same period.
For the range of temperature, or, in other words, the
curvature of the isothermal lines in a given zone, and
at a given period, must always be circumscribed within
narrow limits, the climate of each place in that zone
being controlled by the combined influence of the geo-
graphical peculiarities of all other parts of the earth.
Whereas, if we compare the state of things at tw0
distinct and somewhat distant epochs, a particulat

‘zone may at one time be under the influence of one

class of disturbing causes, and at another time may be
affected by an opposite combination. The lands, for
example, to the north of Greenland cause the present
climate of North America to be colder than that of
Europe in the same latitudes; but the excess of cold
is not so great as it would have been if the western
hemisphere had been entirely isolated, or separated
from the eastern like a distinct planet. For not only
does the refrigeration produced by Greenland chill
to a certain extent the atmosphere of northern and
western Europe, but the mild climate of Europe reacts
also upon North America, and moderates the chilling
influence of the adjoining polar lands.

Ch. VIL] CHANGES OF TEMPERATURE. 191.

To return to the state of the earth after the changes
above supposed, we must not omit to dwell on the im-
portant effects to which a wide expanse of perpetual
Snow would give rise. It is probable that nearly the
whole sea, from the poles to the parallels of 45°, would
be frozen over; for it is well known that the imme-
diate proximity of land is not essential to the formation
and increase of field ice, provided there be in some
part of the same zone a sufficient quantity of glaciers
generated on or near the land, to cool down the sea.
Captain Scoresby, in his account of the arctic regions,
observes, that when the sun’s rays “ fall upon the snow-
Clad surface of the ice or land, they are in a great
Measure reflected, without producing any material
elevation of temperature ; but when they impinge on
the black exterior of a ship, the pitch on one side
Occasionally becomes fluid, while ice is rapidly gener-
ated at the other.”*

“Now field ice is almost always covered with snow+ ;
and thus not only land as extensive as our existing
Continents, but immense tracts of sea in the frigid and
temperate zones, might present a solid surface covered.
With snow, and reflecting the sun’s rays for the greater
Part of the year. Within the tropics, moreover, where
the ocean now predominates, the sky would no longer
be serene and clear, as in the present era ; but masses
of floating ice would cause quick condensations of
vapour, so that fogs and clouds would deprive the ver-
tical rays of the sun of half their power. The whole
planet, therefore, would receive annually a smaller
proportion of the solar influence, and the external crust
Would part, by radiation, with some of the heat which

* See Scoresby’s Arctic Regions, vol. i. p. 378. + Ib. p. 320.

192 483 CAUSES OF 5 [Book I.

had been accumulated in it, during a different state of
the surface. This heat would be dissipated in the
spaces surrounding our atmosphere, which, according
to the calculations of M. Fourier, have a temperature
much inferior to that of freezing water.

After the geographical revolution above assumed,
the climate of equinoctial lands might be brought at
last to resemble that of the present temperate zone,
or perhaps be far more wintery. They who should
then inhabit such small isles and coral reefs as are
now seen in the Indian ocean and South Pacific, would
wonder that zoophytes of large dimensions had once
been so prolific in their seas; or if, perchance, they
found the wood and fruit of the cocoa-nut tree or the
palm silicified by the waters of some ancient mineral
spring, or incrusted with calcareous matter, they would
muse on the revolutions which had annihilated such
genera, and replaced them by the oak, the chestnut,
and the pine. With equal admiration would they
compare the skeletons of their small lizards with the
bones of fossil alligators and crocodiles more than
twenty feet in length, which, at a former epoch, had
multiplied between the tropics: and when they saw 2
pine included in an iceberg, drifted from latitudes
which we now call temperate, they would be astonished
at the proof thus afforded, that forests had once grown
where nothing could be seen in their own times but a
wilderness of snow.

If the reader hesitate to Suppose so extensive an
alteration of temperature as the probable consequence
of geographical changes, confined to one hemisphere;
he should remember how great are the local anomalies
in climate now resulting from the peculiar distribution
of land and sea in certain regions. Thus, in the island

Ch. VIL] CHANGES OF TEMPERATURE. 193

of South Georgia, before mentioned (p. 175.), Captain
Cook found the everlasting snows descending to the
level of the sea, between lat. 54° and 55° S.; no trees
or shrubs were to be seen, and in summer a few rocks
Only, after a partial melting of the ice and snow,-were
Scantily covered with moss and tufts of grass. If such
a climate can now exist at the level of the sea in a
latitude corresponding to that of Yorkshire, in spite of
all those equalizing causes before enumerated, by
Which the mixture of the temperatures of distant
Tegions is facilitated throughout the globe, what
Tigours might we not anticipate in a winter generated
by the transfer of the mountains of India to our arctie
Circle !

But we have still to contemplate the. additional
refrigeration which might be effected by changes in
the relative position of land and sea in the southern
hemisphere. If the remaining continents were trans-
ferred from the equatorial and contiguous latitudes to
the south polar regions, the intensity of cold produced
Might, perhaps, render the globe uninhabitable. We
are too ignorant of the laws governing the direction of
Subterranean forces, to determine whether such a crisis
be within the limits of possibility. At the same time,
it may be observed, that no distribution of land can
Well be imagined more irregular, or, as it were, capri-
cious, than that which now prevails; for at present, by
drawing a line in a particular direction, the globe may
be divided into two equal parts, in such a manner, that
One hemisphere shall be entirely covered with water,
With the exception of some promontories and islands,
while the other shall contain less water than land ; and,
What is still more extraordinary, on comparing the
€xtratropical lands in the northern and southern hemi-

VOL. I. K

194 CAUSES OF [Book L

spheres, the lands in the northern are found to be to
those in the southern in the proportion of thirteen to
one!* To imagine all the lands, therefore, in high,
and all the sea in low latitudes, as delineated in the
annexed plate (Pl.-I.), would scarcely be a more
anomalous state of the surface.

Position of land and sea which might give rise to the
extreme of heat.— Let us now turn from the con-
templation of the winter of the “great year,” and
consider the opposite train of circumstances which
would bring on the spring andsummer. To imagine all
the lands to be collected together in equatorial latitudes,
and a few promontories only to project beyond the
thirtieth parallel, as represented in the annexed map
(fig. 1. Pl. I.), would be undoubtedly to suppose an
extreme result of geological change. But if we con-
sider a mere approximation to such a state of things,
it would be sufficient to cause a general elevation of
temperature. Nor can it be regarded as a visionary
idea, that, amidst the revolutions of the earth’s surface,
the quantity of land should, at certain periods, have been
simultaneously lessened in the vicinity of both the
poles, and increased within the tropics. We must re-
collect that even now it is necessary to ascend to the
height of fifteen thousand feet in the Andes under the
line, and in the Himalaya mountains, which are without
the tropic, to seventeen thousand feet, before we reach
the limit of perpetual snow. On the northern slope;
indeed, of the Himalaya range, where the‘ heat ra-
diated from a great continent moderates the cold,
there are meadows and cultivated land at an elevation
equal to the height of Mont Blane.t If then there

* Humboldt on Isothermal Lines.
+ Humboldt, Tableaux de la Nature, tom, i. p- 112.

MAP S
shewing the position

OF LAND AND SEA

which mightproduce the extremes of

HEAT Aanb COLD

in the Climates of the

GLOBE

Observations. Zhere Maps are intended
to shew that Continents £ Islands having
the same shape and relative dimensions

48 those now existing might be placed so
as to occupy eather the equatorial or polar

legions

Lie Fig. NW? scarcely any of the land eatends

“rom the Equator towards the poles beyond

` tke 30" parallel of Latitude and in Fig.2.

2 vay small proportion of t extends from
the poles towards the Equator beyond the

40% parallel of Latitude.

Ch. VIL] CHANGES OF TEMPERATURE. ` 195

were no arctic lands to chill the atmosphere, and freeze
the sea, and if the loftiest chains were near the line, it
seems reasonable to imagine that the highest moun-
tains might be clothed with a rich vegetation to their
Summits, and that nearly all signs of frost would dis-
appear from the earth.

When the absorption of the solar rays was in no
region impeded, even in winter, by a coat of snow, the
Mean heat of the earth’s crust would augment to con-
Siderable depths, and springs, which we know to be in
general an index of the mean temperature of the
Climate, would be warmer in all latitudes. The waters
of lakes, therefore, and rivers, would be much hotter.
in winter, and would be never chilled in summer by
Melted snow and ice. A remarkable uniformity of
Climate would prevail amid the archipelagos of the
temperate and polar oceans, where the tepid waters
of equatorial currents would freely circulate. The
$eneral humidity of the atmosphere would far exceed
that of the present period, for increased heat would
Promote evaporation in all parts of the globe. The
Winds would be first heated in their passage over the
tropical plains, and would then gather moisture from
the surface of the deep, till, charged with vapour,
they arrived at extreme northern and southern re-
Sions, and there encountering a cooler atmosphere,
discharged their burden in warm rain. If, during the
ong night of a polar winter, the snows should whiten
the summit of some arctic islands, they would be dis-
Solved as rapidly by the returning sun, as are the
Snows of Etna by the blasts of the sirocco.

We learn from those who have studied the geo-
Staphical distribution of plants, that in very low lati-
tudes, at present, the vegetation of small islands remote

K 2

196 CAUSES OF [Book 1.

from continents has a peculiar character; the ferns
and allied’ families, in particular bearing a great pro-
portion to the total number of other plants. Other
circumstances being the same, the more remote the
isles are from the continents, the greater does this
proportion become. Thus, in the continent of India,
and the tropical parts of New Holland, the proportion
of ferns to the phznogamous plants is only as one to
twenty-six ; whereas, in the South-Sea Islands, it is
as one to four, or even as one to three.*

We might expect, therefore, in the summer of the
“ great year,’ which we are now considering, that
there would be a predominance of tree-ferns and
plants allied to palms and arborescent grasses in the
islands of the wide ocean, while the dicotyledonous
plants and other forms now most common in tem-
perate regions would almost disappear from the earth.
Then might those genera of animals return, of which
the memorials are preserved in the ancient rocks of
our continents. The huge iguanodon might reappear
in the woods, and the ichthyosaur in the sea, while
the pterodactyle might flit again through umbrageous
groves of tree-ferns. Coral reefs might be prolonged
once more beyond the arctic circle, where the whale
and the narwal now abound; and droves of turtles
might wander again through regions now tenanted by
the walrus and the seal.

But, not to indulge too far in these speculations, I
may observe, in conclusion, that however great, during
the lapse of ages, may be the vicissitudes of temper-
ature in every Zone, it accords with this theory that

* Ad. Brongniart, Consid. Générales sur la. Nat, de la Végét
&c. Ann. des Sciences Nat. Nov. 1828.

Ch, VILJ CHANGES OF TEMPERATURE. 197

the general climate should not experience any sensible
change in the course of a few thousand years ; because
that period is insufficient to affect the leading features
of the physical geography of the globe. Notwith-
Standing the apparent uncertainty of the seasons, it is
found that the mean temperature of particular localities
1s very constant, when observations made for a suffi-
Cient series of years are compared.

Yet there must be exceptions to this rule, and even
the labours of man have, by the drainage of lakes and
Marshes, and the felling of extensive forests, caused
Such changes in the atmosphere as greatly to raise our
Conception of the more important influence of those
forces to which in certain latitudes, even the existence
of land or water, hill or valley, lake or sea, must be
ascribed. If we possessed accurate information of the
amount of local fluctuation in climate in the course of
twenty centuries, it would often, undoubtedly, be con-
siderable. Certain tracts, for example, on the coast of
Holland and of England consisted of cultivated land
in the time of the Romans, which the sea, by gradual
encroachments, has at length occupied. Here, at least,
a slight alteration has been effected ; for neither the
distribution of heat in the different seasons, nor the
Mean annual temperature of the atmosphere investing

the sea, is precisely the same as that which rests upon
the land.

In those countries, also, where earthquakes and
Volcanos are in full activity, a much shorter period
May produce a sensible variation. The climate of the
once fertile plain of Malpais in Mexico must differ
Materially from that which prevailed before the middle
ofthe last century ; for, since that time, six mountains,

KS

198 CHANGE OF CLIMATE, [Book I.

the highest of them rising sixteen hundred feet above
the plateau, have been thrown up by volcanic erup-
tions. It is by the repetition of an indefinite number
of such local revolutions, and by slow movements
extending simultaneously over wider areas, as will be
afterwards shewn, that a general change of climate
may finally be brought about.

CHAPTER VIII.

FARTHER EXAMINATION OF THE QUESTION AS TO THE
DISCORDANCE OF THE ANCIENT AND MODERN CAUSES
OF CHANGE.

Whether the geographical features of the northern hemisphere, at
the period of the deposition of the oldest fossiliferous strata,
were such as might have given rise to an extremely hot cli-
mate — State of the surface when the greywacké, or transition
formations, originated — State of the same when the mountain
limestone, coal-sandstones, and coal were deposited (p. 204.) —
Changes in physical geography, between the carboniferous
period and the chalk — Abrupt transition from the secondary
to the tertiary fossils (p. 207.) — Accession of land, and
elevation of mountain chains, after the consolidation of the
secondary rocks — Explanation of Map, shewing the area »
covered by sea, since the commencement of the tertiary period
(p. 214.) — Remarks on the theory of the diminution of central
heat (p. 221,) — Astronomical causes of fluctuations in climate
(p. 224.).

Whether the geographical features of the northern hemi-
Sphere, at the period of the deposition of the oldest fos-
siliferous strata, were such as might have given rise to
an extremely hot climate.—In the sixth chapter, I
Stated the arguments derived from organic remains
for concluding that the mean annual temperature of
the northern hemisphere was considerably more ele-
vated when the ancient carboniferous strata were de-
posited than it is at present ; as also that the climate
K 4

200 PROOFS OF FORMER ’ [Book I.

had been modified more than once since that epoch,
and that it had been reduced by successive changes
more and more nearly to that now prevailing in the
same latitudes. Farther, I endeavoured, in the last
chapter, to prove that vicissitudes in climate of no
less importance may be expected to recur in future,
if it be admitted that causes now active in nature have
power, in the lapse of ages, to produce considerable
variations in the relative position of land and sea. It
remains to inquire whether the alterations, which the
geologist can prove to have actually taken place at
former periods, in the geographical features of the
northern hemisphere, coincide in their nature, and in
the time of their occurrence, with such revolutions in
climate as would naturally have resulted, according to
the meteorological principles already explained.

The oldest system of rocks which afford by their
organic remains any decisive evidence as to climate,
or the former position of land and sea, are those gene-
rally known as the transition, or greywacké, formations»
These have been found in England, France, Germany,
Sweden, Russia, and other parts of central and north-
ern Europe, as also in the great Lake district of Canada
and the United States; and they appear to have been
deposited in a sea of considerable extent. The fossils
have been regarded by many naturalists as indi-
cating a greater uniformity in the species of marine
animals inhabiting the sea at that early period than
would now be found to prevail in a similar extent of
ocean. Thenumber and magnitude of the multilocular
or chambered univalves, and of the corals, obtained
from the limestones of this group, recall the forms now
most largely developed in tropical seas. Hitherto few
vegetable remains have been noticed, but such as are

Ch, VIIL] CHANGES IN PHYSICAL GEOGRAPHY. 201

mentioned are said to agree more nearly with the
Plants of the carboniferous era than any other, and
Would therefore imply a tropical and humid atmo-
Sphere.*

Carboniferous group.— This group comes next in the
order of succession, and one of its principal members, the
Mountain limestone, was evidently a marine formation,
as is shewn by the shells and corals which it con-
tains. That the ocean of that period was of consider-
able extent in our latitudes, we may infer from the con-
tinuity of these calcareous strata over large areas. The
Same group appears also to have been traced not only
through different parts of Europe, but also in North
America, towards the borders of the arctic sea.}

The coal itself is admitted to be of vegetable origin,

* Mr. Murchison, during his investigations of the English and
Welsh transition rocks, has not met with any vegetable remains
of land plants; but MM. Elie de Beaumont, Virlet, ‘and De la
Beche have pointed out places where they occur in members of
that series. Mr. Weaver also formerly supposed that the coal and
Coal-plants of Munster, in Ireland, belonged to the transition
rocks ; but he has lately retracted his opinion, and believes that
the coal and plants alluded to occur in the carboniferous series.

+ It appears from the observations of Dr. Richardson, made
during the expedition under the command of Captain Franklin
to the north-west coast of America, and from the specimens pre-
sented by him to the Geological Society of London, that, between
the parallels of 60° and 70° north latitude, there is a great calca-
Teous formation, stretching towards the mouth of the Mackenzie
river, in which are included corallines, producte, terebratule,

&e, having a close affinity in generic character to those of our
Mountain limestone, of which the group has been considered the
€quivalent. There is also in the same region a newer series of
Strata, in which are shales with impressions of ferns, Jepidoden-
drons, and other vegetables, and also ammonites. — Proceedings
F Geol. Soc. No. 7. p. 68. March, 1828.

K 5

202 . CHANGES OF THE SURFACE [Book I.

and the state of the plants, and the beautiful preserv-
ation of their leaves in the accompanying shales,
precludes the idea of their having been floated from
great distances. As the species were evidently ter-
restrial, we must suppose that some dry land was not far
distant ; and this opinion is confirmed by the shells
found in some strata of the Newcastle and Shropshire
coal-fields.* These shells, which are chiefly found in
the upper coal-measures, are referable to freshwater
genera, and lived, perhaps, in lakes or small estuaries.
There are some regions in the northern parts of Eng-
land and Scotland where the marine mountain lime-
stone alternates with strata containing coal. Such an
arrangement of the beds may possibly have been pro-
duced by the alternate rising and sinking of large
tracts, which were first laid dry, and then submerged
again. The land of that period appears to have con-
sisted in part of granitic rocks, the waste of which may
have produced the coarse sandstones, such, for ex-
ample, as the millstone-grit. Volcanic rocks, how-
ever, were not wanting, as in Scotland, for example, in
the present basins of the Forth and Tay, where they
seem to have been poured out on the bottom of the sea
during the accumulation of the carboniferous strata.
The arrangement of the sandstones and shales in
this group has been thought by some geologists, as by
MM. Sternberg, Boué, and Adolphe Brongniart, to
favour the hypothesis of the strata having resulted
from the waste of small islands placed in rows, and
forming the highest points of submarine mountain
chains. The disintegration of such clusters of islands
might produce around and between them detached

* See Mr. W. Hutton, Foss: Flora of Great Brit. Preface, and
Mr. Murchison’s papers on Shropshire, &c.

Ch. VIIL] AND CLIMATE CONTEMPORANEOUS. | 203

deposits, which, when subsequently raised above the
Waters, might resemble the strata formed in a chain
of lakes; for the boundary heights of such apparent
lake-basins would be formed of the rocks once consti-
tuting the islands, and they might still continue, after
their elevation, to preserve their relative superiority of
height, and to surround the newer strata on several
sides.*

This idea is also confirmed by the opinion of many
botanists who have studied with care the vegetation
of the carboniferous period, and who declare that it
possesses the character of an insular flora, such as
might be looked for in islands scattered through a wide
ocean in a tropical and humid climate.

There is, as yet, no well-authenticated instance of
the remains of a saurian animal having been found ina
member of the carboniferous series} Now the larger
oviparous reptiles usually inhabit rivers of considerable
size in warm latitudes; and had crocodiles and other
animals of that class been abundant in a fossil state, as
in some of the newer secondary formations, we must
have inferred the existence of rivers, which could only
have drained large tracts of land. Nor have the bones
of any terrestrial mammalia rewarded our investiga-
tions. Their absence may be regarded by some geolo-
gists as corroborating the theory of the non-existence
of the higher orders of animals in the earlier ages: but
the circumstance may, perhaps, be connected with the

* See some ingenious speculations to this effect, in the work of
M. Ad. Brongniart, Consid. Générales sur la Nat. de la Végét-
&c., Ann. des Sci. Nat. Nov. 1528.

+ The supposed saurian teeth found by Dr. Hibbert in the
carboniferous limestone of Burdie House, near Edinburgh, have
since been clearly referred by Dr. Agassiz to sauroidal fish.

K 6

904: CHANGES OF THE SURFACE [Book I.

geographical condition of the northern hemisphere at
that time ; for it is a general character of small islands
remote from continents, to be altogether destitute of
Jand quadrupeds, except such as appear to have been
conveyed to them by man. Kerguelen’s land, which is
of no inconsiderable size, placed in lat. 49° 20’ S., a
parallel corresponding to that of the Scilly islands, may
be cited as an example, as may all the groups of fer-
tile islands in the Pacific Ocean between the tropics,
where no quadrupeds have been found, except the
dog, the hog, and the rat, which have probably been
brought to them by the natives, and also bats, which
may have made their way along the chain of islands
extending from the shores of New Guinea far into the
southern Pacific.* Even the islands of New Zealand,
which may be compared to Ireland and Scotland in
dimensions, appear to possess no indigenous quad-
rupeds, except the bat; and this becomes the more
striking, when we recollect that the northern extre-
mity of New Zealand stretches to latitude 34°, where
the warmth of the climate must greatly favour the
prolific development of organic life.

So far, then, the examination of the phenomena
exhibited by the greywacké and carboniferous groups
accord well with the prevalence of such a state of
physical geography in the northern hemisphere as
would have given rise to a hot and uniform climate.
The subaqueous aspect of the igneous products, —the
continuity of marine deposits over vast spaces — the
basin-shaped disposition of the fragmentary rocks —
the insular character of the flora—the absence of large
fluviatile reptiles and of land quadrupeds, —all concur

* Prichard’s Phys, Hist. of Man., vol. i. p. 75.

Ch. Vint] AND CLIMATE CONTEMPORANEOUS. 905

to establish the fact of the northern hemisphere hav-
ing been pervaded by a great ocean, interspersed, like
the south Pacific, with small islets or lands of moderate
dimensions, and with insular or submarine volcanos.
Changes in physical geography between the forma-
tion of the carboniferous strata and the chalk. —
We have evidence in England that the strata of the

ancient carboniferous group, already adverted to, were,
in many instances, fractured and contorted, and often
thrown into a vertical position before the deposition of
Some of the newer secondary rocks, such as the new
Ted sandstone.

Fragments of the older formations are sometimes
included in the conglomerates of the more modern; and
Some of these fragments still retain their fossil shells ©
and corals, so as to enable us to determine the parent
rocks from whence they were derived.* There are
other proofs of the disturbance at successive epochs
of different secondary rocks before the deposition of
others; and satisfactory evidence that, during these
reiterated convulsions, the geographical features of the
Northern hemisphere were frequently modified, and
that from time to time new lands emerged from the
deep. The vegetation during some parts of the period

Thus, for example, on the banks of the Avon, in the Bristol
oal-field, the dolomitic conglomerate, a rock of an age interme-
late between the carboniferous series and the lias, rests on the
truncated edges of the coal and mountain limestone, and contains
Tolled and angular fragments of that limestone, in which its charac-
teristic mountain-limestone fossils are seen. For accurate sections
illustrating the disturbances which rocks of the carboniferous
Series underwent before the newer red sandstone was formed, the
*eader should consult the admirable memoir of the south-western

coal district of England, by Dr. Buckland and Mr. Conybeare,
Geol. Trans, vol, i. second series.

206 CHANGES OF THE SURFACE [Book I

in question (from the lias to the chalk inclusive),
appears to have approached to that of the larger
islands of the equatorial zone; such, for example, a$
we now find in the West Indian archipelago.* These
islands appear to have been drained by rivers of con-
siderable size, which were inhabited by crocodiles and
gigantic oviparous reptiles, both herbivorous and car-,
nivorous, belonging for the most part to extinct genera.
Of the contemporary inhabitants of the land we have —
as yet acquired but scanty information, but we know
that there were flying reptiles, insects, and small mam-
mifera, allied to the opossum. _

When describing the Wealden, one of the uppet
members of the great secondary series, and evidently
of freshwater origin, I shall point out the reasons
which incline me to believe that, when those strata
originated, a large continent advanced very near to the
space now occupied by the south-eastern extremity of
England. A river, equal, perhaps, in size to the Ganges
or the Indus, seems to have continued to pour its turbid
waters for ages into the sea in those latitudes at the
period referred to. +

It might at first appear, that the position of a con-
tinent so far tothe north, as the counties of Surrey
and Sussex, at a time when the mean temperature of
the climate is supposed to have been much hotter
than at present, is inconsistent with the theory before
explained, that the heat was caused by the gathering
together of all the great masses of land in low lati-
tudes, while the polar regions were almost entirely
sea. But provided that none of the land was arctic oF

* Ad, Brongniart, Consid. Générales sur la Nat. de la Végét.
&c. Ann. des Sci. Nat., Nov. 1898,
f See Book iv. chap, xxiii,

Ch, VIIL] AND CLIMATE CONTEMPORANEOUS. 207

antarctic, and a large part of the continents intra-
tropical, considerable elevation of temperature may be
Presumed to result, even when large continental tracts
_Were prolonged from the equatorial to the temperate
zone.

Changes during the tertiary periods. —It will be
seen hereafter that the Maestricht beds are classed
as the newest of the secondary series*; and the fossils
of that group, including the remains of gigantic rep-
tiles, indicate the prevalence of a very hot climate.
Between this uppermost member of the secondary
Series, and the oldest of the newer class of formations
called tertiary, there is a remarkable discordance as
to species of organic remains, none having yet been
found common to both. This abrupt transition from
one set of fossils to another, is also accompanied by
evident signs of a change of climate ; the older ter-
tiary species having a far less tropical aspect than
those found fossil in the newest secondary group.

Nor are there wanting signs of a decided coinci-
dence between this alteration of climate, and geogra-
Phical changes which occurred between the formation
of the cretaceous series and that of the older tertiary
group. + On comparing the tertiary formations of dif-
ferent ages, we may trace a gradual approximation in the
imbedded fossils from an assemblage in which extinct
Species predominate, to one where the species agree
for the most part with those now existing. In other
Words, we find a gradual increase of animals and plants
fitted for our present climates, in proportion as the
Strata which we examine are more modern. Now,

* See Book iv. chap. xxiii.

+ See chaps. xxi. and xxii. B. iv. on the period of the elevation
of the chalk of the S. E. of England.

908 . CHANGES OF THE SURFACE [Book I.

during all these successive tertiary periods, there
are signs of a great increase of land in European
latitudes. By reference to the map (PI. IL), and its.
description, p. 214., the reader will see how great have
` been the physical revolutions which have occurred
since the commencement of the tertiary period.

In the present state of Europe, the chalk and asso-
ciated strata are of considerable: extent, and some-
times rise to the summits -of lofty mountains. As all
the members of this group contain almost exclusively
marine remains, it follows that every tract which
they now occupy has, since their origin, been con-
verted from sea into-land, and, in some cases, from
deep sea to mountains of great altitude. We cannot
doubt that part of the changes alluded to happened
before the older tertiary strata originated ; because
these last consist, in a great degree, of the ruins of
the newer secondary rocks; which must therefore
have been raised and exposed to aqueous erosion before
the derivative beds were formed. It will moreover be
seen, in the fourth book, (chap. iii.,) that the secondary
and tertiary formations, considered generally, may be
contrasted as having very different characters ; the
one appearing to have been deposited in open seas,
the other in regions where dry land, lakes, bays, and
perhaps inland seas, abounded. The secondary series
is almost exclusively marine; the tertiary, even the
oldest part, contains lacustrine strata, and not unfre-
quently freshwater and marine beds alternating.

Now, the facts depicted in the map (P1. II. p. 214.),
demonstrate that about. two thirds of the present
European lands have emerged since the earliest of
these tertiary groups originated. Nor is this the only
change which the same region has undergone within

.

Ch, VIIL] AND CLIMATE CONTEMPORANEOUS. 209
this comparatively modern period ; some tracts, which
Were previously land, having gained in altitude, or, on

© contrary, having sunk below their former level,
Within the period alluded to.

The evidence that this rise of land did not take
Place all at the same time, is most striking. Several
ltalian geologists, even before the time of Brocchi,

ad justly inferred that the Apennines were elevated
Several thousand feet above the level of the Medi-
terranean, before the deposition of the recent Sub-
Pennine beds which flank them on either side. What
Now constitutes the central calcareous chain of the
Apennines must for a long time have been a narrow
dgy peninsula, branching off, at its northern extre-
mity, from the Alps near Savona. This peninsula has
‘Ince been raised from one to two thousand feet, by
Which movement the ancient shores, and, for a certain
€Xtent, the bed of the contiguous sea, have been laid
dry, both on the side of the Mediterranean and the
‘Adriatic.

The nature of these vicissitudes will be explained
Y the accompanying diagram, which represents a

transverse section across the Italian peninsula. The
inclined strata A are the disturbed formations of the

Pennines into which the ancient igneous rocks æ are
Supposed to have intruded themselves. At a lower
level on each flank of the chain are the more recent

ae

210 CHANGES OF THE SURFACE [Book I.

shelly beds 6 6, which often contain rounded pebbles
derived from the waste of contiguous parts of the
older Apennine limestone. These, it will be seen,
are horizontal, and lie in what is termed «“ unconform-
able stratification” on the more ancient series. They
now constitute a line of hills of moderate elevation
between the sea and the Apennines, but never pene-
trate to the higher and more ancient valleys of that
chain.

The same phenomena are exhibited in the Alps on
a much grander scale; those mountains being com-
posed in some even of their higher regions of newer
secondary formations, while they are encircled by 4
great zone of tertiary rocks of different ages, both ot
their southern flank towards the plains of the Po, and
on the side of Switzerland and Austria, and at theif
eastern termination towards Styria and Hungary.*
This tertiary zone marks the position of former seas
or gulfs, like the Adriatic, which were many thousand
feet deep, and wherein masses of strata accumulated,
Some single groups of which seem scarcely inferior in
thickness to the whole of our secondary formations in
England. These marine tertiary strata have been
raised to the height of from two to four thousand feet,
and consist of formations of different ages, charac-
terized by different assemblages of organized fossils-
The older tertiary groups generally rise to the greatest
heights, and form interior zones nearest to the central
ridges of the Alps. Although we have not yet ascer-
tained the number of different periods at which the
Alps gained accessions to their height and width, yet

* See a Memoir on the Alps, by Professor Sedgwick and Mr.
Murchison. Trans. of Geol. Soc. second ser. vol. iii. accompanied
by a map. i

Ch. VIIL] AND CLIMATE CONTEMPORANEOUS. 211

we can affirm, that the last series of movements oc-
curred when the seas were inhabited by many existing
Species of animals.

We may imagine some future series of convulsions
Once more to heave up this stupendous chain, together
With the adjoining bed of the sea, so that the moun-
tains of Europe may rival the Andes in elevation; in
Which case the deltas of the Po, Adige, and Brenta,
how encroaching upon the Adriatic, might be uplifted
80 as to form another exterior belt of considerable
height around the south-eastern flank of the Alps.

The Pyrenees, also, have acquired the whole of their
present altitude, which in Mont Perdu exceeds eleven
thousand feet, since the deposition of some of the
hewer or cretaceous members of our secondary series.
The granitic axis of that chain only attains about the
Same height as a ridge formed by marine calcareous
beds, the organic remains of which shew them to be
the equivalents of our chalk and green-sand series.”
The tertiary strata at the base of the chain are raised
to the height of only a few hundred feet above the
Sea, and retain a horizontal position, without partaking
in general in the disturbances to which the older
Series has been subjected; so that the great barrier
between France and Spain was almost entirely up-
heaved in the interval between the deposition of the
Chalk and certain tertiary strata. The Jura, also,
Owes a great part of its present elevation to subterra-
nean convulsions which happened after the deposition
of certain tertiary groups.+

* This observation, first made by M. Boué, has been since Con-
firmed by M. Dufrénoy.
+ M. Elie de Beaumont, Ann. des Sci. Nat., Dec. 1829, p. 346.

212 CHANGES OF THE SURFACE - [Book I.

The remarkable break above alluded to, between the
most modern of the known secondary rocks and the
oldest tertiary, may be in some measure apparent only,
and ascribable to the present deficiency of our inform-
ation*; in which case the signs of the intermediate
steps, by which a passage was effected from one state
of things to another, may hereafter be discovered.
Nevertheless, it is far from impossible that the interval
between the chalk and tertiary formations constituted
an era in the earth’s history, when the transition from
one class of organic beings to another was, compara-
tively speaking, rapid. For if the doctrines above ex-
plained in regard to vicissitudes of temperature are
sound, it will follow that changes of equal magnitude
in the geographical features of the globe, may at dif-
ferent periods produce very unequal effects on climate;
and, so far as the existence of certain animals and
plants depends on climate, the duration of species
would be shortened or protracted, according to the rate
at which the change of temperature proceeded.

Even if we assume that the intensity of the subter-
ranean disturbing forces is uniform and capable of
producing nearly equal amounts of alteration on the
surface of the planet, during equal periods of time,
still the rate of alteration in climate would be by no
means uniform. Let us imagine the quantity of land
between the equator and the tropic in one hemisphere
to be to that in the other as thirteen to one, which, as
before stated, represents the unequal proportion of the
extra-tropical lands in the two hemispheres at present.
Then let the first geographical change consist in the
shifting of this preponderance of land from one side of

* See Book iy. chap. 23.

Ch. VIIL] AND CLIMATE CONTEMPORANEOUS. 213

the line to the other, from the southern hemisphere,
for. example, to the northern. Now this need not
affect the general temperature of the earth, But if, at
another epoch, we suppose a continuance of the same.
agency to transfer an equal volume of land from the
torrid zone to the temperate and arctic regions of the
Northern and southern hemisphere, or into one of
them, there might be so great a refrigeration of the
Mean temperature in all latitudes, that scarcely any of
the pre-existing races of animals would survive, and,
Unless it pleased the Author of Nature that the planet
Should be uninhabited, new species would then be sub-
Stituted in the room of the extinct. We ought not,
therefore, to infer, that equal periods of time are
always attended by an equal amount of change in
Organic life, since a great fluctuation in the mean tem-
Perature of the earth, the most influential cause which
Can be conceived in exterminating whole races of
animals and plants, must, in different epochs, require
Unequal portions of time for its completion.

EXPLANATION OF MAP SHEWING [Book 1.

Map showing the extent of surface in Europe which has been covered
by water since the commencement of the deposition of the older

or Eocene Tertiary strata. (Strata of the Paris and London
Basins, Sc.) *

Tuts map will enable the reader to perceive at a
glance the great extent of change in the physical
geography of Europe, which can be proved to have
taken place since some of the older tertiary strata
began to be deposited. The proofs of submergence,
during some part or other of this period, in all the dis-
tricts distinguished by ruled lines, are of a most un-
equivocal character; for the area thus described is
now covered by deposits containing the fossil remains
of animals which could only have lived under water.
The most ancient part of the period referred: to can-
not be deemed very remote, considered geologically ;
because the deposits of the Paris and London basins,
of Auvergne, and many other districts belonging to the
older tertiary epoch, are newer than the greater part
of the sedimentary rocks, (those commonly called se-
condary and transition, ) of which the crust of the globe
is composed. The species, moreover, of marine and
freshwater: testacea, of which the remains are found
in these older tertiary formations, are not entirely dis-
‘tinct from such as now live; a proportion of more than
three in a hundred of the fossils having been identified
with species now living.t Yet, notwithstanding the

* Constructed chiefly from M, Ami Boué’s Geological Map
of Europe.
+ See Book iv. ch. 5,

ry

|

|

ie

MAP shewing the extent of surface in EUROPE which has been covered by Water
since the commencement of the deposition of the older TERTIARY strata

/ strata of the Paris & London Basins Xe. &c:) Eocene formations.)

Constructed chiefly trom the Geological Map of Europe by M.A, Boue.

Observations

The portion ruled thus comprehends the present Sea, together with the space which can be

roved to have been submerged during some part of the period above mentioned. The whole
eS area thus delineated may never have been submerged at one time but different parts in

succession yetitis probable that the proportion of dry land has during the whole

period been on the increase.

The space coloured Red & Blue may never have been under Water since the commencement

of the cera under consideration but this inference rests on negative evidence and may

require hereatter to be modified ,

_] Primary and Transition Formations f The space left white is either unexplored geologically

or is too little known to warrant an opinion respecting
| tts submergence during the tertiary cpode.

EX e Secondary D?

For a more detailed explanation of this Map, see Book 1 hap. &.

= a

4\0

i

ie Re ee

London:Published by John Murray Albemarle Street.

Ch VII] CHANGES IN PHYSICAL GEOGRAPHY. 215

Comparatively recent epoch to which the retrospect is
Carried, the variations in the distribution of land and
Sa depicted on the map form only a part of those
Which must have taken place during the period under
Consideration. Some approximation has merely been
Made to an estimate of the amount of sea converted into
nd in parts of Europe best known to geologists ; but
We cannot determine how much land has become sea
uring the same period; and there may have been
tepeated interchanges of land and water in the same
Places, changes of which no account is taken in the
map, and respecting the amount of which little’ accu-
tate information can ever be obtained.

IT have extended the sea in two or three instances
€yond the limits of the land now covered by tertiary
mations, because other geological data have been
%btained for inferring the submergence of these tracts
alter the deposition of the tertiary strata had begun.
‘hus I shall explain, in the 4th Book*, my reasons for
“oncluding that part of the chalk of England. (the
dorth and south downs, for example, together with the
ittervening secondary tracts) continued beneath the
‘ea until the Eocene or earliest tertiary beds had
egun to accumulate.

A strait of the sea separating England and Wales
has also been introduced, on the evidence afforded by
Shells of existing species found in a deposit of gravel,
Sand, loam, and clay, called the northern drift by

t. Murchison, who has traced it from Lancashire
to the Bristol channel, over the space indicated in the
map. + Mr. Trimmer has discovered similar recent

* Ch, xxi. and xxii.
t See Proceedings of Geol. Soc, vol. ii. p: 334.

216 EXPLANATION OF MAP SHEWING [Book É

marine shells on the. northern coast of North Wales
and on Moel Tryfane, near the Menai Straits, at the
height of 1392 feet above the level of the sea !

Some raised sea-beaches, one of them at the mouth
of Carlingford Bay, Ireland, in which recent marine
shells occur, lately observed by Professor Sedgwick
and Mr. Murchison, have required an extension of thé
sea over part of the eastern shore of Ireland.

A portion also of the primary district in Brittany "8
divided into islands, because it has been long known t0
be covered with patches of marine tertiary strata ; and
when I examined the disposition of these, in company
with my friend, Captain S. E. Cook, R. N., in 1830, !
was convinced that the sea must have covered much
larger areas than are now occupied by these small and
detached deposits.

The former connexion of the White Sea and thé
Gulf of Finland is proved by the fact that a broad
band of tertiary strata extends throughout part of thé
intervening space. The channel, it is true, is repre
sented as somewhat broader than the tract now occu-
pied by the tertiary formation ; because the latter i
bordered on the north-west by a part of Finland, which
is extremely low, and so thickly interspersed with lakes
as to be nearly half covered with fresh water.

Certain portions of the western shores of Norway
and Sweden have been left blank, because the dis-
covery by Von Buch, Brongniart, and others of de-

posits of recent shellsalong the coasts of those countries

at several places and at various heights above the leve!
of the sea, attests the comparatively recent date of thé
elevation of part of the gneiss and other primary rocks
in that country, although we are unable as yet to deter-
mine how far the sea may have extended.

Ch. VIIL] CHANGES IN PHYSICAL GEOGRAPHY. 217

On the other hand, a considerable space of low land
along the shores on both sides of the Gulf of Bothnia,
in the Baltic, is represented as sea, because the gra-
dual rise of the land and the shoaling of the water on
that coast, known to have taken pied during the his-
torical era, leave no room for doubt that the boundaries
of the gulf must have been greatly contracted within
a comparatively modern period. Beds of sand and
Clay are also found far inland in these parts, containing
fossil shells of species now inhabiting the neighbouring
Seas. A portion of Scania, and other tracts in the
South of Sweden, have also been marked with ruled
lines, because they are covered with clay, sand, and
erratic blocks, which appeared to me, after examining
the district, to be tertiary. If the space overspread by
Such formations were more accurately known, the area
Tepresented as land in this part of Europe, would,
doubtless, be much more circumscribed.

I was anxious, even in the title of this map, to guard
the reader against the supposition that it was intended
to represent the state of the physical geography of part
of Europe at any one point of time. The difficulty, or
rather the impossibility, of restoring the geography of
the globe as it may have existed at any former period,
especially a remote one, consists in this, that we can
only point out where part of the sea has been turned
into land, and are almost always unable to determine
what land may have become sea. All maps, therefore,
Pretending to represent the geography of remote geo-
logical epochs must be ideal. The map under con-
Sideration is not a restoration of a former state of
things, at any particular moment of time, but a synop-

tical view of a certain amount of one kind of change
VOL. I. L

218 CHANGES OF THE SURFACE [Book I.

(the conversion of sea into land) known to have bee?
brought about within a given period.

It may be stated that the movements of earth-
quakes occasion the subsidence as well as the uprais-
ing of the surface ; and that, by the alternate rising
and sinking of particular spaces, at successive periods,
a great area may have been entirely covered with ma
rine deposits, although the whole may never have bee?
beneath the waters at one time ; nay, even though the
relative proportion of land and sea may have continued
unaltered throughout the whole period. I believe
however, that since the commencement of the tertiary
period, the dry land in the northern hemisphere has
been continually on the increase, both because it i$
now greatly in excess beyond the average proportio?
which land generally bears to water on the globe, and be-
cause a comparison of the secondary and tertiary strata
affords indications, as I shall endeavour to shew here-
after, of a passage from the condition of an ocean inter-
spersed with islands to that of a large continent.*

But supposing it were possible to represent all the
vicissitudes in the distribution of land and sea that
have occurred during the tertiary period, and to ex-
hibit not only the actual existence of land where theré
was once sea, but also the extent of surface now sub-
merged which may once have been land, the map
would still fail to express all the important revolutions
in physical geography which have taken place within
the epoch under consideration. For the oscillations of
level, as was before stated, have not merely been such
as to lift up the land from below the waters, but i?
some cases to occasion a rise of several thousand feet

* See Book iv. chap. iii.

Ch, VIIL] AND CLIMATE CONTEMPORANEOUS. 219

above the sea. Thus the Alps have acquired an
additional altitude of from 2000 to 4000 feet, and even
in some places still more ; and the Apennines owe a
considerable part of their height (from 1000 to 2000
feet and upwards) to subterranean convulsions which
have happened within the tertiary epoch.

On the other hand, some mountain chains may have
been lowered during the same series of ages, in an
equal degree, and shoals may have been converted
into deep abysses.*

Concluding remarks on changes in physical geography.
— These observations, it be may be said, are confined to
Europe, and therefore to a space which constitutes but
a small portion of the northern hemisphere; but it
appeared from the remarks offered in the preceding
chapter, that the great Lowland of, Siberia, lying chiefly
between the latitudes 55° and 75° N. (an area nearly
equal to all Europe) is covered for the most part by
marine strata, which, from the account given by Pallas,
and other writers, may be considered as of tertiary
formation.

Upon a review of all the phenomena above enu-
merated, there appear grounds for inferring that the
eras of the principal alterations in climate, as deduced
from fossil remains, were coincident with the periods
of the most remarkable changes in the former position
of seaand land. A wide expanse of ocean interspersed
with islands, seems to have pervaded the northern hemi-
Sphere at the periods when the transition and carboni-

* Tt may be observed, that the facts and inferences exhibited in
this map bear not merely on the theory of climate above proposed,
but serve also to illustrate the views explained in the third book
respecting the migrations of animals and plants, and the gradual
€xtinction of species.

L 2

220 CHANGES OF THE SURFACE [Book I.

ferous rocks were formed, and the temperature was
then hottest and most uniform. Subsequent modifi-
cations in climate accompanied the deposition of the
secondary formations, when repeated changes were
effected in the physical geography of our northern
latitudes. Lastly, the refrigeration became most de-
cided, and the climate most nearly assimilated to that
now enjoyed, when the lands in Europe and northern
Asia had attained their full extension, and the moun-
tain chains their actual height.

It has been objected to this theory of climate, that
there are no geological proofs of the prevalence at any
former period of a temperature lower than that now
enjoyed ; whereas, if the causes above assigned were
the true ones, it might reasonably have been expected
that fossil remains would sometimes indicate colder as
well as hotter climates than those now established.*
In answer to this objection, I may suggest, that our
present climates are probably far more distant from
the extreme of possible heat than from its opposite
extreme of cold. A glance at the map (Pl. I. fig. 1.)
will shew that all the existing lands might be placed
in the zone intervening between the 30th parallels of
latitude on each side of the equator, and that even
then they would by no means fill that space. In no
other position would they give rise to’ so high a tem-
perature. But in the present geographical condition
of the earth, the land excluded from this zone, and
lying between the poles and the parallels of 3 0, is in
great excess ; SO much so that, instead of being to the
sea in the proportion of 1 to 3, which is as near as
possible the average general ratio throughout the

* Allgemeine Literatur Zeitung, No. cxxzix, July, 1833

Ch, VII] AND CLIMATE CONTEMPORANEOUS. Tou.

globe, it is as 9 to 23.* Hence it ought not to sur-

Prise us if, in our geological retrospect, embracing,

Perhaps, a small part only of a complete cycle of change
in the terrestrial climates, we should happen to dis | ioe
every where the signs of a higher temperature. “fhe

Strata hitherto examined may have originated when

the quantity of equatorial land was always decreasing,

and the land in regions nearer the poles augmenting in
height and area, until at length it attained its present
excess in high latitudes. There is nothing improbable

in supposing that the geographical revolutions imme-

diately preceding our times had this tendency ; and in

that case the refrigeration must have been constant,

although, for reasons before explained, the rate of cool-

ing may not have been uniform.

Theory of Central Heat.— The gradual diminution
of the supposed central heat of the globe has been
resorted to by many geologists as the principal cause
of alterations of climate. The matter of our planet is
imagined, according to the conjecture of Leibnitz, to
have been originally in an intensely heated state, and

to have been parting ever since with portions of its

* In this estimate, the space within the antarctic circle, of which
Nothing certain is known, is not taken into account: if included,
it would probably add to the excess of dry land: for the great accu-
mulation of ice in the antarctic region seems to imply the presence
of a certain quantity of terra firma. The number of square miles
on the surface of the globe, are 148,522,000, the part occupied
by the sea being 110,849,000, and that by land, 37,678,000 ; 5O
that the land is very nearly to the sea as 1 part in 4. I am in-
formed by Mr. Gardner, that, according to a rough approximation,
the land between the 30° N. lat. and the pole occupies a space
about equal to that of the sea, and the land between the 30° S. lat,
and the antarctic circle about 4, of that zone.

Tus

999 CHANGES OF THE SURFACE [Book I.

heat, at the same time that it has contracted its di-
mensions. ‘There are, undoubtedly, some grounds for
inferring, from recent observation and experiment, that
the temperature of the earth increases as we descend
from the surface to that slight depth to which man can
penetrate; but there are no proofs of a secular decrease
of heat accompanied by contraction. On the contrary;
La Place has shown, by reference to astronomical
observations made in the time of Hipparchus, that in
the last two thousand years there has been no sensible
contraction of the globe by cooling ; for had this been
the case, even to an extremely small amount, the day
would have been shortened, whereas its length has
certainly not diminished during that period by ;1, th
of a second. Baron Fourier, after making a curious
series of experiments on the cooling of incandescent
bodies, has endeavoured, by profound mathematical
calculations, to prove that the actual distribution of
heat in the earth’s envelope is precisely that which
would have taken place if the globe had been formed
ina medium of a very high temperature, and had after-
wards been constantly cooled.*

Now this conclusion is appealed to by many as cor-
roborating the theory of secular refrigeration, although
the phenomenon might perhaps be ascribed, with equal
propriety, to the action of volcanic heat, which we
know has, in former ages, shifted its points of chief
development over every part of the earth’s crust.

M. Cordier announces, as the result of his experi- -
ments and observations on the temperature of the in-
terior of the earth, that the heat increases rapidly with

* See a Memoir on the Temperature of the Terrestrial Globe,
and the Planetary Spaces, Ann. de Chimie et Phys. tom. xxvii-
p. 136. Oct. 1824.

Ch. VIIL] AND CLIMATE CONTEMPORANEOUS. 223

the depth ; but the increase does not follow the same
law over the whole earth, being twice or three times
as much in one country as in another, and these differ-
ences are not in constant relation either with the
latitudes or longitudes of places.* All this is pre-
cisely what we should have expected to arise from
Variations in the intensity of volcanic heat, and from
that change of position, which the principal theatres
of volcanic action can be proved to have undergone.

But the advocates of the doctrine of central heat
contend, that although no contraction can be demon-
strated to have taken place within the historical period
(the operation being slow and the time of observation
limited), yet it is no less certain that heat is annually
Passing out by radiation from the interior of the globe
into the planetary spaces. Fourier even undertook to
demonstrate that the quantity of heat thus transmitted
into space in the course of every century, through
every square metre of the earth’s surface, would suf-
fice to melt a column of ice having a square metre
for its base, and being three metres (or 9 feet 10
inches) high. On the other hand, it is said, there is
no assignable mode in which this heat can be again
restored to the earth.

Streams of incandescent lava rise up from unknown
depths, flow out upon the surface, and before they
Consolidate emit much light and heat. In what manner
does the igneous and luminous matter thus withdrawn
from our planet return again from the celestial spaces ?
or, if lost, does it not imply a continual cooling of the
Central parts of the earth ?

* See M. Cordier’s Memoir on the Temperature of the Interior
of the Earth, read to the Academy of Sciences, 4th June, 1827.
— Edin. New Phil. Journal, No. viii. p. 273.

LA.

224 ASTRONOMICAL CAUSES OF [Pook 1. .

This argument may appear plausible, until we reflect
how ignorant we are of the sources of volcanic heat,
or indeed of the nature of light and heat in general.
It is doubtless true, that light and heat are continually
emanating from the earth ; but, in the same manner, it
may be said that they escape without intermission
from the sun, and we know not whether there be any
compensating causes which again restore them to that
luminary.— « It is a mystery,” says Herschel, speaking
of the sun, “to conceive how so enormous a conflagra-
tion (if such it be) can be kept up. Every discovery
in chemical science here leaves us completely at a loss,
or rather seems to remove farther the prospect of
probable explanation. May not,” he adds, “a continual
current of electric matter be constantly circulating in
the sun’s immediate neighbourhood, or traversing the
planetary spaces?” &c. &c.*

Astronomical causes of Jluctuations in climate. — Sir
John Herschel has lately inquired, whether there are
any astronomical causes which may offer a possible
explanation of the difference between the actual cli-
mates of the earth’s surface, and those which formerly
appear to have prevailed. He has entered upon this
subject, he Says, “impressed with the magnificence
of that view of geological revolutions, which regards
them rather as regular and necessary effects of great
and general causes, than as resulting from a series of
convulsions and catastrophes, regulated by no laws,
and reducible ‘to no fixed principles.” Geometers, he
adds, have demonstrated the absolute invariability
of the mean distance of the earth from the sun;
whence it would at first seem to follow, that the mean

* Treatise on Astronomy, $ 387

r a aaan a e a S E

Ch. VIIL] CHANGES IN CLIMATE. 225

annual supply of light and heat derived from that
luminary would be alike invariable : but a closer con-
Sideration of the subject will show, that this would not
bea legitimate conclusion ; but that, on the contrary,
the mean amount of solar radiation is dependent on
the excentricity of the earth’s orbit, and therefore
liable to variation.*

_ Now, the excentricity of the orbit, he continues,
1s actually diminishing, and has been so for ages be-
Yond the records of history. In consequence, the ellipse
is in a state of approach to a circle, and the annual ave-
rage of solar heat radiated to the earth is actually on the
decrease. So far this is in accordance with geological
evidence, which indicates a general refrigeration of
climate ; but the question remains, whether the amount
of diminution which the excentricity may have ever
undergone, can be supposed sufficient to account for
any sensible refrigeration. The calculations necessary
to determine this point, though practicable, have never
yet been made, and would be extremely laborious ,
for they must embrace all the perturbations which the

Most influential planets, Venus, Mars, Jupiter, and -

Saturn, would cause in the earth’s orbit, and in each
Other’s movements round the sun.

The problem is also very complicated, inasmuch as
it depends not merely on the ellipticity of the earth’s
orbit, but on the assumed temperature of the celestial

* The theorem is thus stated : — “ The excentricity of the orbit
Varying, the total quantity of heat received by the earth from the
sun in one revolution is inversely proportional to the minor axis
of the orbit. The major axis is invariable, and therefore, of
course, the absolute length of the year: hence it follows that the
mean annual average of heat will also be in the same inverse ratio

of the minor axis.” — Geol. Trans. second series, vol. iii. p. 295.
m

L ə

AEE A ee

PRs NE

296 ' CHANGE OF CLIMATE, [Book Í.

spaces beyond the earth’s atmosphere ; a matter still
open to discussion, and on which MM. Fourier and
Herschel have arrived at very diferent opinions-
But if, says Herschel, we suppose an extreme case,
as if the earth’s orbit should ever become as excentric
as that of the planet Juno, or Pallas, a great change of
climate might be conceived to result, the winter and
summer temperatures being sometimes mitigated, and
at others exaggerated, in the same latitudes.

It is much to be desired that the calculations alluded
to were executed, as even, if they should demonstrate;
as M. Arago thinks highly probable *,. that the mean
amount of solar radiation can never be materially
affected by irregularities in the earth’s motion, it would
still be satisfactory to ascertain the point. Such in-
quiries, however, can never supersede the necessity of
investigating the consequences of the varying position
of continents, shifted as we know them to have been
during successive epochs, from one part of the globe
to the other.

* Ann, du Bur. des Long. 1834.

CHAPTER IX.

FARTHER DISCUSSION OF THE QUESTION AS TO THE Dis
CORDANCE OF THE ANCIENT AND MODERN CAUSES OF
CHANGE,

Theory of the progressive development of organic life-— Evidence
in its support inconclusive — Vertebrated animals, and plants
of the most perfect organization, in strata of very high antiquity
(p. 232.) — Differences between the organic remains of suc-
cessive formations — Remarks on the comparatively modern.
origin of the human race (p. 244,)—— The popular doctrine of
successive development not confirmed by the admission that
man is of modern origin — Introduction of man, to what
extent a change in the system (p> 248.).

Progressive development of organic life.—I1n the pre-
ceding chapters I have considered many of the most
Popular grounds of opposition to the, doctrine, that all
former changes of the organic and inorganic creation
are referable to one uninterrupted succession of phy-
sical events, governed by the laws of Nature now in
Operation.

As the principles of our science must always remain
unsettled so long as no fixed opinions are entertained
on this fundamental question, I shall proceed to ex-
amine other objections which have been urged against
the assumption of the identity of the ancient and mo-
dern causes of change. A late distinguished writer
has formally advanced some of the most popular of
these objections. “It is impossible,” he affirms, “ to

L 6

998 THEORY OF | [Book I.

defend the proposition, that the present order of things
is the ancient and constant order of nature, only modi-
fied by existing laws: in those strata which are deep-
est, and which must, consequently, be supposed to be
the earliest deposited, forms even of vegetable life are
rare; shells and vegetable remains are found in the
next order ; the bones of fishes and oviparous reptiles
exist in the following class; the remains of birds, with
those of the same genera mentioned before, in the next
order ; those of quadrupeds of extinct species ina still
more recent class ; and it is only in the loose and
slightly consolidated strata of gravel and sand, and
which are usually called diluvian formations, that the
remains of animals such as now people the globe are
found, with others belonging to extinct species. But,
in none of these formations, whether called secondary;
tertiary, or diluvial, have the remains of man, or any
of his works, been discovered ; and whoever dwells
upon this subject must be convinced, that the present
order of things, and the comparatively recent existence
of man as the master of the globe, is as certain as the
destruction of acformer and a different order, and the
extinction of a number of living forms which have no
types in being. In the oldest secondary strata there
are no remains of such animals as now belong to the
surface ; and in the rocks, which may be regarded as
more recently deposited, these remains occur but rarely,
and with abundance of extinct species ;— there seems,
as it were, a gradual approach to the present system of
things, and a succession of destructions and creations
preparatory to the existence of man.”*

* Sir H. Davy, Consolations in Travel, Dialogue III. « The
Unknown.”

Ch. 1x.] PROGRESSIVE DEVELOPMENT. 229

In the above passages, the author deduces two im-
Portant conclusions from geological data : first, that in
the successive groups of strata, from the oldest to the
Most recent, there is a progressive development of
organic life, from the simplest to the most complicated
forms ;— secondly, that man is of comparatively recent
origin. It will be easy to shew that the first of these
Propositions, though very generally received, has but
a slender foundation in fact. The second, on the
Contrary, is indisputable ; and it is important, therefore,
to consider how far its admission is inconsistent with
the doctrine, that the system of the natural world
May have been uniform from the beginning, or rather
from the era when the oldest rocks hitherto discovered
Were formed. :

First, then, let us consider the geological proofs ap-
Pealed to in support of the theory of the successive
development of animal and vegetable life, and their
Progressive advancement to a more perfect state. No
Seologists who are in possession of all the data now
€stablished respecting fossil remains, will for a moment
Contend for the doctrine in all its detail, as laid down
by the great chemist to whose opinions we have re-
erred; but naturalists, who are not unacquainted with
Tecent discoveries, continue to defend it in a modified
form, They say that, in the first period of the world,
(by which they mean the earliest of which we have
yet procured any memorials,) the vegetation consisted
almost entirely of cryptogamic plants, while the ani-
mals which co-existed were almost entirely confined to
200phytes, testacea, and a few fish. Plants of a less
Simple structure succeeded in the next epoch, when
°viparous reptiles began also to abound. Lastly, the
terrestrial flora became most diversified and most per-

930 THEORY OF © [Book 1.

fect when the highest orders of animals, the mammi-
fera and birds, were called into existence.
Now in the first place, it may be observed, that many
naturalists are guilty of no small inconsistency in en-
deavouring to connect the phenomena of the earliest
vegetation with a nascent condition of organic life,
and at the same time to deduce from the numerical
predominance of certain types of form, the greater
heat of the ancient climate. The arguments in favour
of the latter conclusion are without any force, unless
we can assume that the rules followed by the Author
of Nature in the creation and distribution of organic
beings were the same formerly as now; and that, as
certain families of animals and plants are now most
abundant in, or exclusively confined to, regions where
there is a certain temperature, a certain degree of
humidity, a certain intensity of light, and other con-
ditions, so also the same phenomena were exhibited at
every former era.
If this postulate be denied, and the prevalence of
particular families be declared to depend on a certain _
order of precedence in the introduction of different
classes into the earth, and if it be maintained that the
standard of organization was raised successively, w€
must then ascribe the numerical preponderance, in the
earlier ages, of plants of simpler structure, not to the
heat, but to those different laws which regulate organic
life in newly created worlds. If, according to the laws
of progressive development, cryptogamic plants always
Aourish for ages before the dicotyledonous order cam
be established, then is the small proportion of the latte”
fully explained; for in this case, whatever may havé
been the mildness or severity of the climate, they could
not make their appearance.

Ch. 1X.) PROGRESSIVE DEVELOPMENT, 931

Before we can infer an elevated temperature in high
latitudes, from the presence of arborescent Ferns,
Lycopodiacez, and plants of other allied families, we
must be permitted to assume, that at all times, past,
Present, and future, a heated and moist atmosphere
Pervading the northern hemisphere has a tendency to
Produce in the vegetation a predominance of analogous
tYpes of form.

In the ancient strata of the carboniferous era, be-
tween 200 and 300 species of plants have been found.
n these, say the authors of the “ Fossil Flora *,” no
traces have been as yet discovered of the simplest
forms of flowerless vegetation, such as Fungi, Lichens,
Hepatice; or Mosses; while, on the contrary, there.
appear in their room Ferns, Lycopodiacex, and sup-
Posed Equisetaceæ, the most perfectly organized
Ctyptogamic plants. In regard to the remains of
monocotyledons of the same strata, they consist of
Palms and plants analogous to Dracenas, Bananas,
and the Arrow Root tribe, which are the most highly
developed tribes of that class. Among the dicotyle-
dons of the same period coniferous trees were abund-
ant, while the fossil Stigmarie, which accompany
them, belonged probably to the most perfectly or-
8anized plants of that class, being allied to the Cactez,
or Euphorbiacee. “But supposing,” continue the
Same authors, “that it could be demonstrated, that
Neither Coniferæ nor any other dicotyledonous plants
existed in the first geological age of land plants, still
the theory of progressive development would be un-
tenable ; because it would be necessary to show that

* Fossil Flora of Great Britain, by John Lindly and William
utton, Esquires. London, 1832. Preface.

239 THEORY OF [Book Í

monocotyledons are inferior in dignity, or, to use #
more intelligible expression, are less perfectly formed
than dicotyledons. So far is this from being the case;
that if the exact equality of the two classes were not
admitted, it would be a question whether monocotyle-
dons are not the more highly organized of the two;
whether palms are not of greater dignity than oaks;
and cerealia than nettles.”

Animal remains in the transition, or greywacké, and
carboniferous strata.— By far the largest part of thé
organic remains found in the earth’s crust consist of
corals and testacea, the bones of vertebrated animals
being comparatively rare. When these occur, they
belong much more frequently to fish than to reptiles
and but seldom to terrestrial mammalia. This might,
perhaps, have been anticipated as the general result 0f
investigation, since all are now agreed that the greate"
number of fossiliferous strata were deposited beneath
the sea, and that the ocean probably occupied in an-
cient times, as now, the greater part of the earth’s sur-
face. We must not, however, too hastily infer from
the absence of fossil bones of mammalia in the oldef
rocks, that the highest class of vertebrated animals did
not exist in the remoter ages. There are regions ab
present, in the Indian and Pacific oceans, co-extensivé
in area with the continents of Europe and North
America, where we might dredge the bottom and draW
up thousands of shells and corals, without obtaining
one bone of a land quadruped. Suppose our mariners
were to report, that on sounding in the Indian Ocea?
near some Coral reefs, and at some distance from the
land, they drew up on hooks attached to their line
portions of a leopard, elephant, or tapir, should we not

#

c
h. IX.] PROGRESSIVE DEVELOPMENT. 233

be Sceptical as to the accuracy of their statements ?
and if we had no doubt of their veracity, might we not
Suspect them to be ‘unskilful naturalists? or, if the
fact were unquestioned, should we not be disposed to
believe that some vessel had been wrecked on the
Spot ?

The casualties must always be rare by which land
(adrupeds are swept by rivers far out into the open
Sea, and still rarer the contingency of such a floating
body not being devoured by sharks or other predaceous
fish, such as were those of which we find the teeth
Preserved in some of the carboniferous strata. But if
the carcass should escape, and should happen to sink
Where sediment was in the act of accumulating, and
if the numerous causes of subsequent disintegration
Should not efface all traces of the body, included for
Countless ages in solid rock, is it not contrary to all
Calculation of chances that we should hit upon the
€xact spot — that mere point in the bed of an ancient
Ocean, where the precious relic was entombed? Can
We expect for a moment, when we have only suc-
Ceeded, amidst several thousand fragments of corals
d shells, in finding a few bones of aquatic or ampha-
bious animals, that we should meet with a single
Skeleton of an inhabitant of the land? .

Clarence, in his dream, saw, “in the slimy bottom
of the deep,”

a thousand fearful wrecks ;
A thousand men, that fishes gnaw’d upon ;
Wedges of gold, great anchors, heaps of pearl.

Had he also beheld, amid “the dead bones that lay
Scattered by,” the carcasses of lions, deer, and the

í

234 THEORY OF [Book I.

other wild tenants of the forest and the plain, the fiction
would have been deemed unworthy of the genius of
Shakspeare. So daring a disregard of probability and
violation of analogy would have been condemned a$
unpardonable, even where the poet was painting those
incongruous images which present themselves to a dis-
turbed imagination during the visions of the night.

But, as fossil mammiferous remains have been met
with in strata of the more modern periods, it will be
desirable to take a rapid view of the contents of suc
cessive geological formations, and inquire how far they
confirm or invalidate the opinions commonly enter-
tained respecting the doctrine of successive develop”
ment.

In the first place it should be stated, that faint traces
of animal remains make their appearance in strata of a$
early a date as any in which the impressions of plants
have been detected. We are as yet but imperfectly
acquainted with the fossils of the deposits called by
Werner “ transition,” or those below the carboniferous
series; yet in some of these, as in the limestone of

Ludlow, for example, scales and bones of fish hav
been found.* In these ancient rocks we cannot e%
pect to bring many vertebral remains to light until we
have obtained more information respecting the z00°
phytes and testacea of the same period. The rare"
species cannot be discovered until the more abundant
have been found again and again; and it may be
doubted whether we shall ever succeed in acquiring
so extensive a knowledge of the fossil bodies of strata
anterior to the coal as to entitle us to attach much it”
portance to the absence of birds and mammalia. 12

* Murchison, Proceedings of Geol. Soc, No. 34. p. 13.

c
RIX] PROGRESSIVE DEVELOPMENT. 235

ocks of high antiquity many organic forms have been
obliterated by various causes, such as subterranean heat
‘td the percolation of acidulous waters, which have
*Perated during a long succession of ages. The number
af Organic forms which have disappeared from the
dest strata may be conjectured from the fact, that
eir former existence is in many cases merely revealed
to us by the unequal weathering of an exposed face of
tock, on which the petrifactions stand out in relief.
If we next consider the old red sandstone, we find
: at entire skeletons of fish have been discovered in
both in Scotland and in the West of England, and
ales, but no well-authenticated instance is recorded
of a fossil reptile from this formation.* Neither have
ey reptilian remains been met with in the incumbent
“arboniferous group, either in the mountain limestone,
r in the shales and sandstones of the coal. The
SUpposed saurian teeth found by Dr. Hibbert in car-
Oniferous strata, near Edinburgh, have been lately
shewn by Dr. Agassiz to belong to sauroidal fish, or
Sh of the highest rank in structure, and approaching
Nore nearly in their osteological characters than any
thers to true saurians.
It would be premature to conclude that no bones of
Teptiles are to be found in the carboniferous formation,
“cause it is only within a few years that several dis-

* Scales of a tortoise nearly allied to Trionyx, are stated in the

eol, Trans, second series, vol. iii. part 1. p. 144., to have been
found abundantly in the bituminous schists of Caithness, in Scot-
and, and in the same formation in the Orkneys. These schists
have been shewn by Professor Sedgwick and Mr. Murchison to be
of the age of the old red sandstone. But M. Agassiz has lately
®cided that the scales in question are those of a fish (see figure of
them, plate 16., Geol. Trans., same part).

236 THEORY OF [Book Í

tinct species and genera of fish have been ascertainel’
to abound in the same. It should also be recollected
that if we infer from the fossil flora of the coal, and
other circumstances before enumerated, that our latt
tudes were occupied at the remote period in question bY
an ocean interspersed with small islands, such island
may, like those of the modern Pacific, have been almo%
entirely destitute of mammalia and reptiles.*

In regard to birds, they are usually wanting in dë
posits of all ages, even where fossil animals of th?
highest order occur in abundance. +

There was evidently a long period, of which th®
formations from the magnesian limestone to the chalk
inclusive may be said to contain the history, whe
reptiles of various kinds were largely developed on thé
earth : their remains are particularly numerous in the
lias and oolitic strata. As there are now mammal? _
entirely confined to the land, others which, like the bat
and vampyre, fly in the air ; others, again, of amp)”
bious habits, which inhabit rivers, like the hippop®
tamus, otter, and beaver; others exclusively aquatl?
and marine, like the seal, whale, and narwal, so #
the early ages under consideration, there were te
restrial, winged, and aquatic reptiles. There wet
iguanodons walking on the land, pterodactyles winging
their way through the air, monitors and crocodiles #
the rivers, and the ichthyosaur and plesiosaur in thé
ocean. It appears also that some of these ancient
saurians approximated more nearly in their organiz-
ation to the type of living mammalia than do any of
our existing reptiles, ;

I shall not dwell here on a question, which will

* See p. 204. + See Book iii, ch. 15.

T PROGRESSIVE DEVELOPMENT. = 237
sarards be discussed more fully, how far the almost
we suppression of one class of vertebrata and the
velopment of another, as, for example, the pre-
re inance of reptiles over mammalia, or of these over
Ptiles, may be reconcileable with the notion of con-
“tant and uniform laws governing the distribution of
imal life at particular periods.* I shall now merely
“lll the reader’s attention to a striking exception to
© general rule of the non-occurrence of any signs of
warm-blooded quadrupeds in secondary rocks.

n the oolite of Stonesfield, a rock which has been
n ascertained to hold a somewhat inferior position
ù the great oolitic series, the jaws of at least two

®cies of small mammiferous quadrupeds have been
ound, A specimen of one of these, now in the Oxford
a. (see fig. 5.), was examined by M. Cuvier,
Pronounced by him to be allied to the didelphis.
“cording to this naturalist, it was probably a small
carnivorous animal not larger than a mole, yet differ-
S ftom all known carnivora in having ten teeth in a

Natural size.

0 à
Wer jaw of a mammiferous quadruped, from the slate of Stones-
field near Oxford.+

* B x
Ook iv. chap. xxiii.
his figure {No. 5.) is from a drawing by Professor C. Prevost,

Publi :
blished Ann, des Sci. Nat., Avril, 1825. The fossil is a lowerjaw,

238 THEORY OF Book J

Another specimen now in London, in the collectio?
of Mr. Broderip, consists also of a lower jaw, a
belonged certainly toa quadruped of a distinct spel
or even genus (see fig. 6.) for the number of teet?
is different, and agrees precisely with that of the
living didelphis. :

Fig. 6.

Natural size.

Lower jaw of Didelphis Bucklandi, from Stonesfield.*

1. The jaw magnified twice in length.
2. The second molar tooth magnified six times.

adhering by its inner side to the slab of oolite, in which it is A
ise

The form of the condyle, or posterior process of the jaw, is
tinctly seen, an impression of it being left on the stone, althous
the bone is wanting. The anterior part of the jaw has been pe
tially broken away, so that the fangs of six molar teeth are a
fixed in their sockets, the form of the fangs being character"
of the mammalia. The enamel of some of the teeth is well P“
served. vga
* This figure (No. 6.) is taken from the original, 1» ;
Broderip’s collection. It consists of the right half of a lower J? ;
of which the inner side is seen. The jaw contains seven ™° š
teeth, one canine, and three incisors, but the end of the jaw is frat

Ch. 1X.) PROGRESSIVE DEVELOPMENT. 239

The occurrence of these individuals, the most ancient
Memorials yet known of the mammiferous type, so low
Wn in the oolitic series, while no other represent-
atives of the same class have yet been found in the
Süperior secondary strata, either in the Middle or
. Pper Oolite, or in the Wealden, Green Sand, or Chalk,
Sa Striking fact, and should serve as a warning to us
Against hasty generalizations. So important an excep-
Hon to a general rule may be perfectly consistent with
the Conclusion, that a small number only of mammalia
thabited European latitudes when our secondary rocks
Were formed ; but it seems fatal to the theory of pro-
Stessive development, or the notion that the order of
Precedence in the creation of animals, considered
£ ronologically, coincided with the order in which
they would be ranked according to perfection or com-
Plexity of structure.

Of the Tertiary strata.— The tertiary strata, as will
APpear from what has been already stated, were de-
posited when the physical geography of the northern

€misphere had been entirely altered. Large inland
akes had become numerous, as in Central France and
many other countries. There were gulfs of the sea,
mto which considerable rivers emptied themselves,
Where strata were formed like those of the Paris basin.

€re were then also littoral formations in progress,

tured, and traces of the alveolus of a fourth incisor are seen.
ith this addition, the number of teeth would agree exactly with

those of a lower jaw of a didelphis. The fossil is well preserved

‘Na slab of oolitic structure containing shells of Trigoniz and

Other marine remains, Two other jaws, besides those above
*epr esented, have been procured from the quarries of Stonesfield,
~= See Broderip, Zool, Journ. vol. iii. p. 408.

240 THEORY OF [Book 1

such as are indicated by the English Crag, and the-
Faluns of the Loire. The state of preservation of thé
organic remains of this period is very different from that
of fossils in the older rocks, the colours of the shells:
and even the cartilaginous ligaments uniting the valves,
being in some cases retained. More than 1100 species
of testacea have been found in the beds of the Paris basi
and nearly an equal number in the more modern form
ations of the Subapennine hills ; and it is a most curious’
fact in natural history, that the zoologist has already
acquired more extensive information concerning th?
testacea which inhabited the ancient seas of northe™™
datitudes at those remote epochs than of the species
now living in the same parallels in Europe.

Paris basin.—The strata of the Paris basin até
partly of freshwater origin, and filled with the spoils
of the land. They have afforded a great number of
skeletons of land quadrupeds, but these relics are co?”
fined almost entirely to one small member of the group
and their conservation may be considered as having
arisen from some local and accidental combinatio?
of circumstances.* On the other hand, the scarcit¥
of terrestrial mammalia in submarine sediment js eluc’
dated, in a striking manner, by the extremely smal
number of such remains hitherto procured from thé
calcaire grossier, one of the formations of the Parisi@®
series. +

London clay— Plastic clay. — The inferior membe”
of our oldest tertiary formation in England, usually
termed the plastic clay, has hitherto proved as destitut®
of mammiferous remains as our ancient coal strat@:
and this point of resemblance between these deposits

* Book iv. ch. xviii. + Ibid.

Ch. 1x.] PROGRESSIVE DEVELOPMENT. 241]

is the more worthy of observation, because the lignite,
m the one case, and the coal in the other, are exclu-
sively composed of terrestrial plants. From the Lon-
on clay we have procured three or four hundred
Species of testacea, but the only bones of vertebrated
animals are those of reptiles and fish. On comparing,
therefore, the contents of these marine strata with
those of our oolitic series, we find the supposed order
of precedence inverted. In the more ancient system
of rocks, a few mammalia have been recognized ;
Whereas in the newer, if negative evidence were to
be our criterion, Nature has made a retrograde, in-
Stead of an advancing movement, and no animals more
exalted in the scale of organization than reptiles are
discoverable. It should, however, be stated, that in
a freshwater formation, resting upon the London clay,
in the Isle of Wight, and like it belonging to the Eocene
€poch, some mammiferous remains have recently been
found. * t
Subapennine beds.— Although the Subapennine strata
have been examined by collectors for three hundred
Years, and have yielded more than a thousand species of
testacea, the authenticated examples of imbedded re-
Mains of terrestrial mammalia are extremely scanty ;
and several of those which have been cited by earlier
Writers as belonging to the elephant or rhinoceros,
have since been declared, by competent anatomists, to
€ the bones of whales and other cetacea. In about five
or ten instances, perhaps, bones of the mastodon, rhi-
Noceros, and some other land animals, have been
Observed in this formation with marine shells attached.

* Buckland and Allan, Jameson’s Ed. Phil. Journ., No. 27.

T 190. Pratt, Geol. Trans. 2nd series, vol. iii. p. 451. — Read,
830.

VOL. I. M

249 THEORY OF [Book I.

These must have been washed into the bed of the
ancient sea when the strata were forming, and they
serve to attest the contiguity of land inhabited by large
herbivora, which renders the rarity of such exceptions
more worthy of attention. Onthe contrary, the num-
ber of skeletons of existing animals in the upper Val
d’Arno, which have been usually considered to be
referable to the same age as the Subapennine beds;
occur in a deposit which was formed entirely in aD
inland lake, surrounded by lofty mountains.*

Not a single bone of any quadrumanous animal has
ever yet been discovered in a fossil state; and thet
absence has appeared, to some geologists, to counte-
nance the idea that the type of organization most
nearly resembling the human came last in the ordet
of creation, and was scarcely perhaps anterior to that
of man. But the evidence on this point is quite in-
conclusive ; for, first, we know nothing of the details
of the various classes of the animal kingdom which may
have inhabited the land when the secondary strata were
accumulated ; and in regard to some of the more
modern tertiary periods, the climate of Europe does
not appear to have been of such a tropical characte"
as may have been necessary for the development of
the tribe of apes, monkeys, and allied genera. Besides
it must not be forgotten, that almost all the animals
which occur in subaqueous deposits are such as fre-
quent marshes, rivers, or the borders of lakes, as the
rhinoceros, tapir, hippopotamus, ox, deer, pig, and
others. Species which live in trees are extremely
rare in a fossil state; and we have no data as yet for
determining how great a number of the one kind we

* See Book iv. ch. xvi.

Ch. IX.J PROGRESSIVE DEVELOPMENT. 243

Ought to find, before we have a right to expect a single
individual of the other. Even therefore, if we were
led to infer, from the presence of crocodiles and
turtles in the London clay, and from the cocoa-nuts
and spices found in the Isle of Sheppey, that at the
period when our older or Eocene tertiary strata were
formed, the climate was hot enough for the qua-
drumanous tribe, we nevertheless could not hope
to discover any of their skeletons until we had made
Considerable progress in ascertaining what were
the contemporary Pachydermata; and a very small
number of these have, as was before remarked, been
hitherto discovered in any strata of this epoch in
England.

The result then, of our inquiry into the evidence of
the successive development of the animal and vege-
table kingdoms, may be stated in a few words. In
Tegard to plants, if we neglect the obscure and
ambiguous impressions found in some of the oldest
fossiliferous rocks, which can lead to no safe con-
Clusions, we may consider those which characterize
the great carboniferous group as the first deserving par-
ticular attention. They are by no means confined to the
Simplest forms of vegetation, as to cryptogamic plants ;
but, on the contrary, belong to all the leading divisions
of the vegetable kingdom ; some of the more fully
developed forms, both of dicotyledons and monocoty-
ledons having already been discovered, even among
the first three or four hundred species brought to
light : it is therefore superfluous to pursue this part of
: the argument farther.
= Ifwe then examine the animal remains of the oldest
formations, we find bones and skeletons of fish in
the old red sandstones, and even in some transition

M 2

DAA UNIFORMITY OF THE SYSTEM. [Book I.

limestones below it ; in other words, we have already
vertebrated animals in the most ancient strata respect-
ing the fossils of which we can be’ said to possess any
accurate information.

In regard to birds and quadrupeds, their remains are
almost entirely wanting in marine deposits of every
era, even where interposed freshwater strata contain
those fossils in abundance, as in the Paris basin. The
secondary strata of Europe are for the most part
marine, and there is as yet only one instance of the
occurrence of mammiferous fossils in them, four or five
individuals having been found in the slate of Stones-
field, a rock unquestionably of the Oolitic period, and
which appears, from several other circumstances, to
have been formed near the point where some river
entered the sea.

When we examine the tertiary groups, we find in the
Eocene or oldest strata of that class the remains of a
great assemblage of the highest or mammiferous class,
all of extinct species, and in the Miocene beds, or those
of a newer tertiary epoch, other forms, for the most
part of lost species, and almost entirely distinct from
the Eocene tribes. Another change is again perceived,
when we investigate the fossils of later or of the Plio-
cene periods. But in this succession of quadrupeds,
we cannot detect any signs of a progressive develop-
ment of organization, —any indication that the Eocene
fauna was less perfect than the Miocene, or the Mio-
cene, than what will be designated in the fourth book
the Newer Pliocene.

Recent origin of man.— If then the popular theory
of the successive development of the animal and vege-
table world, from the simplest to the most perfect
forms, rests on a very insecure foundation ; it may be

Ch. IX.] RECENT ORIGIN: OF MAN. 24:5

asked, whether the recent origin of man lends any sup-
Port to the same doctrine, or how far the influence of
Man may be considered as such a deviation from the
analogy of the order of things previously established,
as to weaken our confidence in the uniformity of: the
Course of nature.

I need not dwell on the proofs of the low antiquity
of our species, for it is not controverted by any expe-
rienced geologist ; indeed, the real difficulty consists in
tracing back the signs of man’s existence on the earth
to that comparatively modern period when species,
how his contemporaries, began to predominate. If
there be a difference of opinion respecting the occur-
rence in certain deposits of the remains of man and his
Works, it is always in reference to strata confessedly of
the most modern order ; and it is never pretended that
Our race co-existed with assemblages of animals and
Plants, of which all or even a great part of the species
are extinct. From the concurrent testimony of history
and tradition, we learn that parts of Europe, now the
Most fertile and most completely subjected to the
dominion of man, were, less than three thousand years
ago, covered with forests, and the abode of wild beasts.
The archives of nature are in perfect accordance with
historical records; and when we lay open the most
Superficial covering of peat, we sometimes find therein
the canoes of the savage, together with huge antlers
of the wild stag, or horns of the wild bull. In caves
Now open to the day in various parts of Europe, the

bones of large beasts of prey occur in abundance; and
they indicate that, at periods comparatively modern 1n
the history of the globe, the ascendancy of man, if he
existed at all, had scarcely been felt by the brutes.*

* Respecting the probable antiquity assignable to certain human
M 3

246 UNIFORMITY OF THE SYSTEM. [Book ©

No inhabitant of the land exposes himself to so
many dangers on the waters as man, whether in a
savage or a civilized state*; and there is no animal,
therefore, whose skeleton is so liable to become im-
bedded in lacustrine or submarine deposits: nor can
it be said that his remains are more perishable than
those of other animals; for in ancient fields of battle,
as Cuvier has observed, the bones of men have suffered
as little decomposition as those of horses which were
buried in the same grave.+ But even if the more
solid parts of our species had disappeared, the impres-
sion of their form would have remained engraven on
the rocks, as have the traces of the tenderest leaves of
plants, and the soft integuments of many animals.
Works of art, moreover, composed of the most inde-
structible materials, would have outlasted almost all
the organic conterits of sedimentary rocks. Edifices,
and even entire cities, have, within the times of history;
been buried under volcanic ejections, submerged be-
neath the sea, or engulphed by earthquakes; and had
these catastrophes been repeated throughout an inde-
finite lapse of ages, the high antiquity of man would
have been inscribed in far more legible characters on
the framework of the globe than are the forms of the
ancient vegetation which once covered the islands of
the northern ocean, or of those gigantic reptiles which
at still later periods peopled the seas and rivers of the
northern hemisphere. +

Dr. Prichard has argued that the human race have
Sh ee oy 1b 2igsod apti io ag
bones and works of art found intermixed with remains of extinct
animals in several caves in France, see Book iii. ch. xiv.

* See Book iii. ch. xvi, t Ibid.

+ Ibid,

Ch. 1x.} RECENT ORIGIN OF MAN. 247

not always existed on the surface of the earth, because
“the strata of which our continents are composed
Were once a part of the ocean’s bed” — “ mankind had
à beginning, since we can look back to the period
When the surface on which they lived began to exist.”*
This proof, however, is insufficient, for many thousands
of human beings now dwell in various quarters of. the
globe where marine species lived within the times of
history, and, on the other hand, the sea now prevails
Permanently over large districts once inhabited by
thousands of human beings. Nor can this interchange
of sea and land ever cease while the present causes
are in existence. It is conceivable, therefore, that
terrestrial species might be older than the continents
Which they inhabit, and aquatic species of higher anti-
quity than the lakes and seas which they people.
Doctrine of successive development not confirmed by
the admission that man is of modern origin.—It is on
other grounds that we are entitled to infer that man
is, comparatively speaking, of modern origin; and
if this be assumed, we may then ask whether his in-
troduction can be considered as one step in a progres-
Sive system, by which, as some suppose, the organic
World advanced slowly from a more simple toa more
Perfect state? In reply to this question, it should first
be observed, that the superiority of man depends not on
those faculties and attributes which he shares in com-
mon with the inferior animals, but on his reason, by
Which he is distinguished from them. When it is said
that the human race is of far higher dignity than were
any pre-existing beings on the earth, it is the intel-
€ctual and moral attributes only of our race, not the

* Phys. Hist. of Mankind, vol. ii. pe 594.
M 4

e

IAS UNIFORMITY OF THE SYSTEM. [Book 1.

animal, which are considered; and it is by no means
clear, that the organization of man is such as would
confer a decided pre-eminence upon him, if, in place
of his reasoning powers, he was merely provided
with such instincts as are possessed by the lower
animals,

If this be admitted, it would by no means follow;
even if there had been sufficient geological evidence
in favour: of the theory of progressive development,
that the creation of man was the last link in the same
chain. For the sudden passage from an irrational to @
rational animal is a phenomenon of a distinct kind from
_ the passage from the more simple to the more perfect
forms of animal oganization and instinct. To pretend
that such a step, or rather leap, can be part of a regu-
lar series of changes in the animal world, is to strain
analogy beyond all reasonable bounds.

Introduction of man, to what extent a change in the
system. — But setting aside the question of progressive
development, another and a'far more difficult one
may arise out of the admission that man is compara-
tively of modern origin. Is not the interference of
the human species, it may be asked, such a deviation
from the antecedent course of physical events, that the
knowledge of such a fact tends to destroy all our con-
fidence in the uniformity of the order of nature, both
in regard to time past and future ? _ If such an inno-
vation could take place after the earth had been ex-
clusively inhabited for thousands of ages by inferior
animals, why should not other changes as extraor-
dinary and unprecedented happen from time to time?
If one new cause was permitted to supervene, differ-
ing in kind and energy from any before in operation,
why may not others have come into action at different

Ch 1X] RECENT ORIGIN OF MAN. 24:9

€pochs? Or what security have we that they may
Not arise hereafter? And if such be the case, how
Can the experience of one period, even though we are
acquainted with all the possible effects of the then
€Xisting causes, be a standard to which we can refer
all natural phenomena of other periods ?

Now these objections would be unanswerable, if
adduced against one who was contending for the abso-
lute uniformity throughout all time of the succession
of sublunary events—if, for example, he was disposed
to indulge in the philosophical reveries of some Egyp-
tian and Greek sects, who represented all the changes
both of the moral and material world as repeated at
distant intervals, so as to follow each other in their
former connexion of place and time. For they com-
Pared the course of events on our globe to astro-
Nomical cycles; and not only did they consider all
Sublunary affairs to be under the influence of the celes-
tial bodies, but they taught that on the earth, as well
as in the heavens, the same identical phenomena re-
Curred again and again in a perpetual vicissitude.
The same individual men were doomed to be re-born,
and to perform the same actions as before; the same
ats were to be invented, and the same cities built and

destroyed. The Argonautic expedition was destined

to Sail again with the same heroes, and Achilles with
his Myrmidons to renew the combat before the walls

of Troy.

Alter erit tum Tiphys, et altera que vehat Argo
Dilectos heroas : erunt etiam altera bella,
Atque iterum ad Trojam magnus mittetur Achilles.*

* Virgil, Eclog. iv. For an account of these doctrines, see
Dugald Stewart's Elements of the Philosophy of the Human
M 5

250 UNIFORMITY OF THE SYSTEM, [Book 1.

The geologist, however, may condemn these tenets
as absurd, without running into the opposite extreme,
and denying that the order of nature has, from the
earliest periods, been uniform in the same sense if
which we believe it to be uniform at present, and
expect it to remain so in future. We have no reason
to suppose, that when man first became master of 4
small part of the globe, a greater change took place in
its physical condition than is now experienced when
districts, never before inhabited, become successively
occupied by new settlers. When a powerful European
colony lands on the shores of Australia, and introduces
at once those arts which it has required many cen-
turies to mature; when it imports a multitude of plants
and large animals from the opposite extremity of the
earth, and begins rapidly to extirpate many of the in-
digenous species, a mightier revolution is effected in @
brief period than the first entrance of a savage horde,
or their continued occupation of the country for many
centuries, can possibly be imagined to have produced.
If there be no impropriety in assuming that the system
is uniform when disturbances so unprecedented occur
in certain localities, we can with much greater con-
fidence apply the same language to those primeval
ages when the aggregate number and power of the
human race, or the rate of their advancement in civil-
ization, must be supposed to have been far inferior
In reasoning on the state of the globe immediately
before our species was called into existence, we must
be guided by the same rules of induction as when we
speculate on the state of America in the interval that

Mind, vol. ii. chap. ii. sect, 4,, and Prichard’s Egypt. Mythol-
P. 177. :

Ch. 1X.] RECENT ORIGIN OF MAN. ' 951

elapsed between the introduction of man into Asia, the
Supposed cradle of our race, and the arrival of the first
adventurers on the shores of the New World. In that
interval, we imagine the state of things to have gone
n according to the order now observed in regions un-
occupied by man. Even now, the waters of lakes,
Seas, and the great ocean, which teem with life, may
be said to have no immediate relation to the human
tace— to be portions of the terrestrial system of which
Man has never taken, nor ever can take, possession ;
80 that the greater part of the inhabited surface of the
Planet may remain still as insensible to our presence
as before any isle or continent was appointed to be
ur residence.

If the barren soil around Sydney had at once become
fertile upon the landing of our first settlers; if, like
the happy isles whereof the poets have given us such
Slowing descriptions, those sandy tracts had begun to
Yield spontaneously an annual supply of grain, we
might then, indeed, have fancied alterations still more
remarkable in the economy of nature to have attended
the first coming of our species into the planet. Or if,
When a volcanic island like Ischia was, for the first
time, brought under cultivation by the enterprise and
industry of a Greek colony, the internal fire had
become dormant, and the earthquake had remitted
its destructive violence, there would then have been
Some ground for speculating on the debilitation of the
Subterranean forces, when the earth was first placed
Under the dominion of man. But after a long interval
of rest, the volcano bursts forth again with renewed
nergy, annihilates one half of the inhabitants, and
compels the remainder to emigrate. The course of
Nature remains evidently unchanged; and, in like

M 6

252 UNIFORMITY OF THE SYSTEM. [Book I,
i Pii ae

manner, we may suppose the general condition of the
globe, immediately before and after the period when
our species first began to exist, to have been the same,
with the exception only of man’s presence.

The modifications in the system of which man is
the instrument, do not, perhaps, constitute so great a
deviation from previous analogy as we usually imagine ;
we often, for example, form an exaggerated estimate
of the extent of our power in extirpating some of the
inferior animals, and causing others to multiply ; 2
power which is circumscribed within certain limits;
and which, in all likelihood, is by no means exclu-
sively exerted by our species.* The growth of human
population cannot take place without diminishing the
numbers, or causing the entire destruction, of many
animals. The larger. carnivorous Species give way
before us, but other. quadrupeds of smaller size, and
innumerable birds, insects, and plants, which are ini-
mical to our interests, increase in spite of us, some
attacking our food, others our raiment and persons;
and others interfering with our agricultural and horti-
cultural labours. We behold the rich harvest which
we have raised with the sweat of our brow devoured
by myriads of insects, and are often as incapable of
arresting their depredations, as of staying the shock
of an earthquake, or the course of a stream of lava.

A great philosopher has observed, that we can com-
mand nature only by obeying her laws; and this prin-
ciple is true even in regard to the astonishing changes
which are superinduced in the qualities of certai®
animals and plants by domestication and garden cul-
ture.’ I shall point out in the third book that we can

* See Book iii. ch. ix,

Ch. 1x,] RECENT ORIGIN OF MAN. 253

Only effect such surprising alterations by assisting the
development of certain instincts, or by availing our-
Selves of that mysterious law of their organization, by
Which individual peculiarities are transmissible from
ne generation to another.*

It is probable from these, and many other consider-
ations, that as we enlarge our knowledge of the sys-
tem, we shall become more and more convinced, that
the alterations caused by the interference of man
deviate far less from the analogy of those effected by
other animals than is usually supposed. t We are often
misled, when we institute such comparisons, by our
knowledge of the wide distinction between the instincts
of animals and the reasoning power of man ; and we
are apt hastily to infer, that the effects of a rational
and an irrational species, considered merely as physical
agents, will differ almost as much as the faculties by
Which their actions are directed.

It is not, however, intended that a real departure
from the antecedent course of physical events cannot
be traced in the introduction of man. If that latitude of
action which enables the brutes to accommodate them-
Selves in some measure to accidental circumstances,
Could be imagined to have been at any former period
80 great, that the operations of instinct were as much

iversified as are those of human reason, it might,
Perhaps, be contended, that the agency of man did not
Constitute an anomalous deviation from the previously
€stablished order of things. It might then have been
Said, that the earth’s becoming at a particular period
the residence of human beings, was an era in the
Moral, not in the physical world—that our study and

* See Book iii. ch. iii. + Id. chapters v. vi. vii. and ix.

254 UNIFORMITY OF THE SYSTEM. [Book I

contemplation of the earth, and the laws which govern
its animate productions, ought no more to be con-
sidered in the light ofa disturbance or deviation from
the system, than the discovery of the satellites of
Jupiter should be regarded as a physical event affect-
ing those heavenly bodies. Their influence in ad-
vancing the progress of science among men, and in
aiding navigation and commerce, was accompanied by
no reciprocal action of the human mind upon the
economy of nature in those distant planets; and 89.
the earth might be conceived to have become, at 4
certain period, a place of moral discipline, and intel-
lectual improvement to man, without the slightest
derangement of a previously existing order of changé
in its animate and inanimate productions.

The distinctness, however, of the human from all
other species, considered merely as an efficient cause
in the physical world, is real ; for we stand in a relation
to contemporary species of animals and plants widely
different from that which other irrational animals can
ever be supposed to have held to each other. We
modify their instincts, relative numbers, and geo-
graphical distribution, in a manner superior in degree;
and in some respects very different in kind, from that
in which any other species can affect the restio “Bes
sides, the progressive movement of each successive
generation of men causes the human Species to differ
more from itself in power at two distant periods, than
any one species of the higher order of animals differs
from another. The establishment, therefore, by geo-
logical evidence, of the first intervention of such 4
peculiar and unprecedented agency, long after other
parts of the animate and inanimate world existed,

Ch, 1x.) - RECENT ORIGIN OF MAN. 255

affords ground for concluding that the experience
during thousands of ages of allthe events which may
happen on this globe would not enable a philosopher
P Speculate with confidence concerning future con-
Ungencies.

If then an intelligent being, after observing the
Order of events for an indefinite series of ages, had
Witnessed at last so wonderful an innovation as this,
to what extent would his belief in the regularity of the
System be weakened ?— would he cease to assume
that there was permanency in the laws of nature ?—
Would he no longer be guided in his speculations by
the strictest rules of induction ? To these questions it
May be answered, that, had he previously presumed to
dogmatize respecting the absolute uniformity of the
order of nature, he would undoubtedly be checked
by witnessing this new and unexpected event, and
Would form a more just estimate of the limited range
of his own knowledge, and the unbounded extent of
the scheme of the universe. But he would soon per-
ceive that no one of the fixed and constant laws of the
animate or inanimate world was subverted by human
gency, and that the modifications produced were on
the occurrence of new and extraordinary circumstances,
and those not of a physical but a moral nature. The
deviation permitted would also appear to be as slight
as was consistent with the accomplishment of the new
Moral ends proposed, and to be in a great degree
temporary in its nature, so that, whenever the power
of the new agent was withheld, even for a brief period,
à relapse would take place to the ancient state of
things ; the domesticated animal, for example, re-
Covering in a few generations its wild instinct, and the

256 UNIFORMITY OF THE SYSTEM. [Book £

garden-flower and fruit-tree reverting to the likeness
of the parent stock,

Now, if it would be reasonable to draw such infer-
ences with respect to the future, we cannot but apply
the same rules of induction to the past. We have n0
right to anticipate any modifications in the results of
existing causes in time to come, which are not cor
formable to analogy, unless they be produced by the
progressive development of human power, or perhaps
by some other new relations which may hereafter
spring up between the moral and material worlds. Ip
the same manner, when we speculate on the vicissitudes
of the animate and inanimate creation in former ages;
we ought not to look for any anomalous results, unless
where man has interfered, or unless clear indications
appear of some other moral source of temporary
derangement.

For the discussion of other popular objections ad-
vanced against the doctrine of the identity of the

ancient and modern causes of change, especially those
founded on the supposed suddenness of general catas-
trophes, and the transition from one set of organic
remains to another, I must refer to the 4th Book, In
the mean time, when difficulties arise in interpreting
the monuments of the past, I deem it more consistent
with philosophical caution to refer them to our present
ignorance of all the existing agents, or all their pos-
sible effects in an indefinite lapse of time, than to causes
formerly in operation, but which have ceased to act;
and if in any part of the globe the energy of a cause
appears to have decreased, I consider it more probable
that the diminution of intensity in its action is merely
local, than that its force is impaired throughout the

Ch. 1X.] RECENT ORIGIN OF MAN. 257

Whole globe. But should there appear reason to be-
leve that certain agents have, at particular periods of
Past time, been more potent instruments of change
Over the entire surface of the earth than they now
are, it is still more consistent with analogy to presume,
that after an interyal of quiescence they will recover
their pristine vigour, than to imagine that they are
Worn out.

The geologist who assents to the truth of these
Principles will deem it incumbent on him to examine
With minute attention all the changes now in progress
on the earth, and will regard every fact collected
tespecting the causes in diurnal action, as affording
im a key to the interpretation of some mystery in
the archives of remote ages. His estimate of the
Value of geological evidence, and his interest in the
nVestigation of the earth’s history, will depend en-
4rely on the degree of confidence which he feels
in regard to the permanency of the great causes of
change, Their constancy alone will enable him to
teason from analogy, and to arrive, by a comparison
of the state of things at distinct epochs, at the know-
edge of the general laws which govern the economy
of our system.

The uniformity of the plan being once assumed,
vents which have occurred at the most distant periods
m the animate and inanimate world will be acknow-
edged to throw light on each other, and the deficiency
of our information respecting some of the most obscure
Parts of the present creation will be removed. For as,
Y Studying the external configuration of the existing
land and its inhabitants, we may restore in imagination
the appearance of the ancient continents which have

258 UNIFORMITY OF THE SYSTEM. [Book Í!

passed away, so may we obtain from the deposits of
ancient seas and lakes an insight into the nature of the
subaqueous processes now in operation, and of many
forms of organic life, which, though now existing)
are veiled from sight. Rocks, also, produced by sub-
terranean fire in former ages at great depths in thé
bowels of the earth, present us, when upraised by
gradual movements, and exposed to the light of heaven,
with an image of those changes which the deep-seated
volcano may now occasion in the nether regions. Thus
although we are mere sojourners on the surface of thé
planet, chained to a mere point in space, enduring but
for a moment of time, the human mind is not only
enabled to number worlds beyond the unassisted ken
of mortal eye, but to trace the events of indefinite
ages before the creation of our race, and is not eve”
withheld from penetrating into the dark secrets &
the ocean, or the interior of the solid globe; free, like

the spirit which the poet described as animating thé
universe,

ire per omnes
Terrasque, tractusque maris, coelumque profundum.

BOOK II.

CHANGES OF THE INORGANIC WORLD.

Aqugous CAUSES.

CHAPTER I.

Ta of the subject into changes of this otganip and inorganic
* — Inorganic causes of change divided into aqueous and
a Aqueous causes first considered — Destroying and

Sporting power of running water — Sinuosities of rivers —
T streams when united do not occupy a bed of double sur-
(p. 265.) — Heavy matter removed by torrents and floods
~Tecent inundations in Scotland — Effects of glaciers and

Ic 4 2: +
3 ebergs in removing stones — Erosion of chasms through hard
o 2 5 A § ers
* tks (p. 272. )— Excavations in the lavas of Etna by Sicilian
i : %

Vers — Gorge of the Simeto — Gradual recession of the cata-

ra Pi
cts of Niagara.

eion of the aa CRA was defined to be
ts, ae which investigates the former changes
ka, taken place in the organic, as well as in the
Pa; ‘oy kingdoms of nature; and we may next pro-
a Sa, inquire. what changes- are now in progress

these departments. Vicissitudes in the in-

Orsan;
san
ic world are most apparent ; and as on them all

OA iù the animate creation must in a great
e e depend, they may claim our first consideration.
may a agents of change in the inorganic world
Ee ch. ivided into two principal classes, the aqueous
igneous. To the aqueous belong Rivers,

260 ACTION OF RUNNING WATER. [Book 1l

Torrents, Springs, Currents, and Tides ; to the igneous
Volcanos and Earthquakes. Both these classes aê
instruments of decay as well as of reproduction ; bu!
they may also be regarded as antagonist forces. Fo
the aqueous agents are incessantly labouring to reduc?
the inequalities of the earth’s surface to alevel ; while
the igneous are equally active in restoring the uneve?”
ness of the external crust, partly by heaping up ne¥
matter in certain localities, and partly by depressing
one portion, and forcing out another, of the earth's
envelope.

It is difficult, in a scientific arrangement, to give a
accurate view of the combined effects of so maby
forces in simultaneous operation ; because, when W°
consider them separately, we cannot easily estimat?
either the extent of their efficacy, or the kind of
results which they produce. We are in danger, therë
fore, when we attempt to examine the influence e%
erted singly by each, of overlooking the modificatio?®
which they produce on one another; and these are 8°
complicated, that sometimes the igneous and aqueoU®
forces co-operate to produce a joint effect, to which
neither of them unaided by the other could give ris®
—as when repeated earthquakes unite with running
water to widen a valley ; or when a thermal spring
rises up from a great depth, and conveys the mineral
ingredients with which it is impregnated from thé
interior of the earth to the surface. Sometimes thé
organic combine with the inorganic causes ; as whe?
reef, composed of shells and corals, protects one lin?
of coast from the destroying power of tides or currents
and turns them against some other point ; or whe?
drift timber, floated into a lake, fills a hollow to which

Sh 1] ACTION OF RUNNING WATER. 261
the stream would not have had sufficient velocity to
Convey earthy sediment.

It is necessary, however, to divide our observations
° these various causes, and to classify them system-
tically, endeavouring as much as possible to keep in
View that the effects in nature are mixed, and not
Simple, as they may appear in an artificial arrangement.

In treating, in the first place, of the aqueous causes,
We may consider them under two divisions : first, those
Which are connected with the circulation of water from
the land to the sea, under which are included all the
Phenomena of rivers and springs; secondly, those which
arise from the movementsof water in lakes, seas, and the
cean, wherein are comprised the phenomena of tides
ùd currents. In turning our attention to the former
division, we find that the effects of rivers may be sub-
divided into those of a destroying and those of a re-
‘ovating nature; in the destroying are included the
ĉrosion of rocks, and the transportation of matter to
Ower levels; in the renovating class, the formation of
deltas by the influx of sediment, and the shallowing of
Stag,

Action of running water.—I shall begin, then, by
“scribing the destroying and transporting power of
"inning water, as exhibited by torrents and rivers. It
'S Well known that the lands elevated above the sea
attract, in proportion to their volume and density, a
arger quantity of that aqueous vapour which the
fated atmosphere continually absorbs from the sur-
àce of lakes and the ocean. By these means, the
igher regions become perpetual reservoirs of water,
Which descend and irrigate the lower valleys and
Plains. In consequence of this provision, almost all

262 DESTROYING AND TRANSPORTING POWER © [Book 1}

the water is first carried to the highest regions, and #
then made to descend by steep declivities towards th?
sea ; so that it acquires superior velocity, and removes
a greater quantity of soil, than it would do if the ra”
had been distributed over the plains and mountains
equally in proportion to their relative areas. Almo%
all the water is also made by these means to p3%
over the greatest distances which each region affords .
before it can regain the sea. The rocks also, in th?
higher regions, are particularly exposed to atm
spheric influences, to frost, rain, and vapour, and t0
great annual alternations of cold and heat, of moistu%
and desiccation.

Its destroying and transporting power.— Among th?
most powerful agents of decay may be mentioned th%
property of water which causes it to expand during
congelation ; so that, when it has penetrated into the
crevices of the most solid rocks, it rends them op”
on freezing with mechanical force. For this reas
although in cold climates the comparative quantity ;
rain which falls is very inferior, and although it de-
scends more gradually than in tropical regions, yet the
severity of frost, and the greater inequalities of temp”
. ature, compensate in some degree for this diminishe
source of degradation. The solvent power of wate!
also is very great, and acts particularly on the C%
careous and alkaline elements of stone, especially whe?
it holds carbonic acid in solution, which is abundantly
supplied to almost every large river by springs, 4?
is collected by rain from the atmosphere. The 0%)”
gen of the atmosphere is also gradually absorbed by al
animal and vegetable productions, and by almost @
mineral masses exposed to the open air. It gradually

Ta

Ch. 1.7 OF RUNNING’ WATER. 263
ol

x

destroys the equilibrium of the elements of rocks, and
tends to reduce into powder, and to render fit for soils,
ven the hardest aggregates belonging to our globe.*

When earthy matter has once been intermixed with
tunning water, anew, mechanical power is obtained by.
the attrition of sand and pebbles, borne along with
Violence by a stream. Running water charged with
foreign ingredients being thrown against a rock, ex-
favates it by mechanical force, sapping and under-
Mining till the superincumbent portion is at length
Precipitated into the stream. The obstruction causes
à temporary increase of the water, which then sweeps
down the barrier.

Sinuosities of Rivers.— By a repetition of these land-
Slips, the ravine is widened into a small, narrow valley,
in which sinuosities are caused by the deflexion of the
Stream first to one side and then to the other. The
Unequal hardness of the materials through which the
channel is eroded, tends partly to give new directions
to the lateral force of excavation. When by these, or
by accidental shiftings of the alluvial matter in the
Channel, and numerous other causes, the current is
Made to cross its general line of descent, it eats out a
Curve in the opposite bank, or in the side of the hills

Sunding the valley, from which curve it is turned
ack again at an equal angle, so that it recrosses the
Ne of descent, and gradually hollows out another curve
Ower down in the opposite bank, till the whole sides
of the valley, or river-bed, present a succession of
Salient and retiring angles. Among the causes of de-
Viation from a straight course by which torrents and
tivers tend in mountainous regions to widen the valleys

* Sir H. Davy, Consolations in Travel, p. 271.

264: TRANSPORTING POWER [Book I.

through which they flow, may be mentioned the con-
fluence of lateral torrents, swollen irregularly at dif-
ferent seasons by partial storms, and discharging at
different times unequal quantities of debris into the
main channel.

When the tortuous flexures of a river are extremely
great, the aberration from the direct line of descent 15
often restored by the river cutting through the isthmus
which separates two neighbouring curves. Thus, i?
the annexed diagram, the extreme sinuosity of the-

river has caused it to return for a brief space in a cod"
trary direction to its main course, so that a peninsula
is formed, and the isthmus (at a) is consumed on both
sides by currents flowing in opposite directions. Jn
this case an island is soon formed,—on either side ®
which a portion of the stream usually remains.

Transporting power of water.—In regard to the
transporting power of water, we may often be surprise
at the facility with which streams of a small size, an
descending a slight declivity, bear along coarse sa?
and gravel; for we usually estimate the weight °
rocks in air, and do not reflect on their comparativ?
buoyancy when submerged in a denser fluid. boss
specific gravity of many rocks is not more than twi?
that of water, and very rarely more than thrice, 5°
that almost all the fragments propelled by a strea
have lost a third, and many of them half, of what W?
usually term their weight.

Ch, 1. OF RUNNING WATER. 265

It has been proved by experiment, in contradiction
to the theories of the earlier writers on hydrostatics, to
be a universal law, regulating the motion of running
Water, that the velocity at the bottom of the stream is
every where less than in any part above it, and is
Sreatest at the surface. Also, that the superficial
Particles in the middle of the stream move swifter
than those at the sides. This retardation of the low-
€st and lateral currents is produced by friction; and
_When the velocity is sufficiently great, the soil com-
Posing the sides and bottom gives way. A velocity of
three inches per second at the bottom is ascertained to
be sufficient to tear up fine clay,—six inches per
Second, fine sand,—twelve inches per second, fine
Sravel, — and three feet per second, stones of the size
of an egg.* .

When this mechanical power of running water is
Considered, we are prepared for the transportation of
large quantities of gravel, sand, and mud, by the tor-
Tents and rivers which descend with great velocity
from mountainous regions. But a question naturally
arises, how the more tranquil rivers of the valleys and
Plains, flowing on comparatively level ground, can
remove the prodigious burden which is discharged
into them by their numerous tributaries, and by what
Means they are enabled to convey the whole mass to
the sea. If they had not this removing power, their
Channels would be annually choked up, and the valleys
of the lower country, and plains at the base of moun-
‘ain-chains, would be continually strewed over with
fragments of rock and sterile sand. But this evil is
Prevented by a general law regulating the conduct of
running water —that two equal streams do not, when

* Encyc, Brit. — art, Rivers.
VOL. I. N

256 TRANSPORTING POWER [Book IL

united, occupy a bed of double surface. In other
words, when several rivers unite into one, the super-
ficial area of the fluid mass is far less than that
previously occupied by the separate streams. The
collective waters, instead of spreading themselves out
over a larger horizontal space, contract themselves into
a column of which the height is greater relatively to
its breadth. Hence a smaller proportion of the whole
is retarded by friction against the bottom and sides of
the channel; and in this manner the main current is
often accelerated in the lower country, even where the
slope of the river’s bed is lessened.

It not unfrequently happens, as will be afterwards
demonstrated by examples, that two large rivers, after
their junction, have only the surface which one of them
had previously; and even in some cases their united
waters are confined in a narrower bed than each of
them filled before. By this beautiful adjustment, the
water which drains the interior country is made con-
tinually to occupy less room as it approaches the sea;
and thus the most valuable part of our continents,
the rich deltas, and great alluvial plains, are prevented
from being constantly under water.*

Floods in Scotland, 1829.— Many remarkable illus-
trations of the power of running water in moving
stones and heavy materials were afforded by the storm
and flood which occurred on the 3d and 4th of August,
1829, in Aberdeenshire and other counties in Scotland-
The elements during this storm assumed all the cha-
racters which mark the tropical hurricanes ; the wind
blowing in sudden gusts and whirlwinds, the lightning
and thunder being such as is rarely witnessed in oUt

* See article Rivers, Encyc. Brit.

Ch. 1] OF RUNNING WATER. 267

climate, and heavy rain falling without intermission.
The floods extended almost simultaneously, and with
€qual violence, over that part of the north-east of
Scotland which would be cut off by two lines drawn
from the head of Lochrannoch, one towards Inverness
and the other to Stonehaven. The united line of the
different rivers which were flooded could not be less
than from five to six hundred miles in length ; and the
Whole of their courses were marked by the destruction
of bridges, roads, crops, and buildings. Sir T.
Lauder has recorded the destruction of thirty-eight
bridges, and the entire obliteration of a great number
of farms and hamlets. On the Nairn, a fragment of
Sandstone, fourteen feet long by three feet wide and
one foot thick, was carried above two hundred yards
down the river. Some new ravines were formed on the
Sides of mountains where no streams had previously
flowed, and ancient river-channels, which had never
been filled from time immemorial, gave passage to a
Copious flood.*

The bridge over the Dee at Ballatu consisted of five
arches, having upon the whole a water-way of 260
fet. The bed of the river, on which the piers rested,
Was composed of rolled pieces of granite and gneiss,
The bridge was built of granite, and had stood un-
injured for twenty years; but the different parts were
Swept away in succession by the flood, and the whole

eg of masonry disappeared in the bed of the river.

“The river Don,” observes Mr. Farquharson, in his
account of the inundations, “has upon my own pre-
Mises forced a mass of four or five hundred tons of

k Sir T. D. Lauder’s Account of the Great Floods in Moray-
Shire, Aug. 1829.

N 2

268 TRANSPORTING POWER [Book II.

stones, many of them two or three hundred pounds
weight, up an inclined plane, rising six feet in eight
or ten yards, and left them in a rectangular heap,
about three feet deep, on a flat ground ; — the heap
ends abruptly at its lower extremity,” *

The power even of a small rivulet, when swoln by
rain, in removing heavy bodies, was lately exemplified
in the College, a small stream which flows at a mode-
rate declivity from the eastern water-shed of the
Cheviot-Hills. Several thousand tons’ weight of gravel
and sand were transported to the plain of the Till, and
a bridge then in progress of building was carried away;
some of the arch-stones of which, weighing from half
to three quarters of a ton each, were propelled two
miles down the rivulet. On the same occasion, the
current tore away from the abutment of a mill-dam 2
large block of greenstone-porphyry, weighing nearly
two tons, and transported it to the distance of 4
quarter of a mile. Instances are related as occurring
repeatedly, in which from one to three thousand tons
of gravel are, in like manner, removed by this streamlet
to still greater distances in one day.+

In the cases above adverted to, the waters of the
river and torrent were dammed back by the bridges:
which acted as partial barriers, and illustrate the irre-
sistible force of a current when obstructed. Bridges
are also liable to be destroyed by the tendency of rivers
to shift their course, whereby the pier, or the rock
on which the foundation stands, is undermined.

When we consider how insignificant are the volume
and velocity of the rivers and streams in our island,

* Quarterly Journ. of Sci. &c. No. xii. New Series, p. 331-
T Seea paper by Mr. Culley, F. G. S., Proceedings of Geol.
Soc. No. 12. 1829.

Ch. 1.) OF ICEBERGS. 269

when compared to those of the Alps and other lofty
chains, and how, during the successive changes which
the levels of various districts have undergone, the
Contingencies which give rise to floods must have
been multiplied, we may easily conceive that the
quantity of loose superficial matter distributed over
Europe must be considerable. That the position also
of a great portion of these travelled materials should
how appear most irregular, and should often bear no
relation to the existing water-drainage of the country,
is a necessary consequence, as we shall afterwards see,
of the combined operations of running water and sub-
terranean movements.

Effects of ice in removing stones.—In mountainous
regions and high northern latitudes, the moving of
heavy stones by water is greatly assisted by the ice
which adheres to them, and which, forming together
with the rock a mass of less specific gravity, is readily
borne along.* The snow which falls on the summits
of the Alps throughout nine months of the year is
drifted into the higher valleys, and being pressed down-
ward by its own weight, forms those masses of ice and
Snow called glaciers. Large portions of these often
descend into the lower valleys, where they are seen in
the midst of forests and green pastures. The mean
depth of the glaciers descending from Mont Blanc is
from 80 to 100 feet, and in some chasms is seen to
amount to 600 feet.+ The surface of the moving
mass is usually loaded with sand and large stones,
derived from the disintegration of the surrounding
rocks acted upon by frost. These transported mate-

* Silliman’s Journal, No. xxx. p. 303.
+ Saussure, Voy. dans les Alpes, tom. i. p. 440.
N 3

270 TRANSPORTING POWER OF {Book I.

rials are generally arranged in long ridges or mounds,
sometimes thirty or forty feet high. They are often
two, three, or even more in number, like so many
lines of intrenchment, and consist of the debris which
have been brought in by lateral glaciers. The whole
accumulation is called in Switzerland “ the moraine,”
which is slowly conveyed to inferior valleys, and left
where the snow and ice melt, upon the plain, the
larger blocks remaining, and the smaller being swept
away by the stream to which the melting of the ice
gives rise. This stream flows along the bottom of
each glacier, issuing from an arch at its lower ex-
tremity.

In northern latitudes, where glaciers descend into
valleys terminating in the sea, great masses of ice
on arriving at the shore, are occasionally detached and
floated off together with their “moraine.” The cur-
rents of the ocean are then often instrumental in
transporting them to great distances. Scoresby
counted 500 icebergs drifting along in latitude 69°
and 70° north, which rose above the surface from the
height of one to two hundred feet, and measured from
a few yards toa mile in circumference.* Many of
these contained strata of earth and stones, or were
loaded with beds of rock of great thickness, of which
the weight was conjectured to be from fifty thousand
to one hundred thousand tons. Such bergs must be
of great magnitude; because the mass of ice below
the level of the water is between seven and eight
times greater than that above. Wherever they are
dissolved, it is evident that the “moraine” will fall to
the bottom of the sea. In this manner may submarine

* Voyage in 1822, p. 233.

Ch. 1] $ ICEBERGS AND ICE ISLANDS. FTA
valleys, mountains, and platforms become strewed
Over with scattered blocks of foreign rock, of a nature
Perfectly dissimilar from all in the vicinity, and which
may have been transported across unfathomable
abysses. We have before stated, that some ice islands
have been known to drift from Baffin’s Bay to the
Azores, and from the South Pole to the immediate
heighbourhood of the Cape of Good Hope.*

M. Lariviere relates that, being at Memel, on the

Baltic, in 1821, when the ice of the river Niemen broke
up, he saw a glacier thirty feet long, which had de-
Scended the stream, and had been thrown ashore. In
the middle of it was a triangular piece of granite about
a yard in diameter, resembling in composition the red
granite of Finland. + Many rocky fragments are in
‘this manner introduced by rivers into the Baltic ; and
Some of much larger dimensions are carried annually
by the ice from one place to another in the Gulf of
Bothnia, where the sea freezes every winter to the
depth of five or six feet. Blocks of stone resting on
shoals are first frozen in, and then on the melting of
the snow as summer approaches, when the waters of
the gulf rise about three feet, they are lifted up and
conveyed to great distances by the ice, which in that
Season has broken up into floating islands.

Excavation of rocks by running water. —The ra-
Pidity with which even the smallest streams hollow
out deep channels in soft and destructible soils is re-
markably exemplified in volcanic countries, where the
sand and half-consolidated tuffs oppose but a slight

* For farther remarks on the transporting power of glaciers, see
Book iv. ch. 11.

+ Consid. sur les Blocs Errat., 1829.
N 4

272 EROSION OF RAVINES. [Book I.

resistance to the torrents which descend the mountain
side. After the heavy rains which followed the erup-
tion of Vesuvius in 1822, the water flowing from the
Atrio del Cavallo cut, in three days, a new chasm
through strata of tuff and ejected volcanic matter, tO
the depth of twenty-five feet. I found the old mule-
road, in 1828, intersected by this new ravine.

The gradual erosion of deep chasms through some
of the hardest rocks, by the constant passage of run-
ning water charged with foreign matter, is another
phenomenon of which striking examples may be ad-
duced. Illustrations of this excavating power are
presented by many valleys in central France, where
the channels of rivers have been barred up by solid
currents of lava, through which the streams have re-
excavated a passage to the depth of from twenty to
seventy feet and upwards, and often of great widths
In these cases there are decisive proofs that neither
the sea, nor any denuding wave or extraordinary body
of water, has passed over the spot since the melted
lava was consolidated. Every hypothesis of the in-
tervention of sudden and violent agency is entirely
excluded, because the cones of loose scoriæ, out of
which the lavas flowed, are oftentimes at no great
elevation above the rivers, and have remained undis-
turbed during the whole period which has been suffi-
cient for the hollowing out of such enormous ravines: *

Recent excavation by the Simeto.—But I shall at
present confine myself to examples derived from
events which have happened since the time of history:

At the western base of Etna, a great current of
lava (A a, fig. 8.), descending from near the summit

_ * See Book iy. ch, 19.

Ch L] © ‘LAVA EXCAVATED‘ BY THE SIMETO. 273

of the great volcano, has flowed to the distance of five
or six miles, and then reached the alluvial plain of the

Fig. 8.

2
> Bed of

ee Simeto

ort ace by - B

N ; 3 us v
pai S PE 4
2 ee ae Cae

Recent excavation of lava at the foot of Etna by the river Simeto.

Simeto, the largest of the Sicilian rivers, which skirts
the base of Etna, and falls into the sea a few miles
South of Catania. The lava entered the river about
three miles above the town of Aderno, and not only
occupied its channel for some distance, but, crossing
to the opposite side of the valley, accumulated there
in a rocky mass. Gemmellaro gives the year 1603
as the date of the eruption.* The appearance of the
current clearly proves that it is one of the most
Modern of those of Etna: for it has not been covered.
or crossed by subsequent streams or ejections, and the
Olives on its surface are all of small size, yet older
than the natural wood on the same lava. In the course,
therefore, of about two centuries, the Simeto has eroded
a passage from fifty to several hundred feet wide, and
in some parts from forty to fifty feet deep.

The portion of lava cut through is in no part porous
or scoriaceous, but consists of a compact homogeneous
mass of hard blue rock, somewhat inferior in weight to

* Quadro Istorico dell’ Etna, 1824. Some doubts are enter-
tained as to the exact date of this current by others, but all agree
that it is not one of the older streams even of the historical era.

NS

274 LAVA EXCAVATED BY THE SIMETO. [Book Il.

ordinary basalt, and containing crystals of olivine and
glassy felspar. The general declivity of this part of
‘the bed of the Simeto is not considerable ; but, in con-
sequence of the unequal waste of the lava, two water-
falls occur at Passo Manzanelli, each about six feet i
height. Here the chasm (B, fig. 8.) is about forty
feet deep, and only fifty broad.

The sand and pebbles in the river-bed consist chiefly
of a brown quartzose sandstone, derived from the upper
country; but the materials of the volcanic rock itself
must have greatly assisted the attrition. This river;
like the Caltabiano on the eastern side of Etna, has
not yet cut down to the ancient bed of which it was
dispossessed, and of which the probable position is
indicated in the annexed diagram (c, fig. 8.).

On entering the narrow ravine where the water
foams down the two cataracts, we are entirely shut out
from all view of the surrounding country ; and a geolo-
gist who is accustomed to associate the charateristic
features of the landscape with the relative age of cer-
tain rocks, can scarcely dissuade himself from the be-
lief that he is contemplating a scene in some rocky
gorge of a primary district. The external forms of
the hard blue lava are as massive as any of the most
ancient trap-rocks of Scotland. The solid surface is iD
some parts smoothed and almost polished by attrition,
and covered in others with a white lichen, which im-
parts to it an air of extreme antiquity, so as greatly to
heighten the delusion. But the moment we re-ascend
the cliff the spell is broken: for we scarcely recede 4
few paces, before the ravine and river disappear, and
we stand on the black and rugged surface of a vast
current of lava, which seems unbroken, and which we
can trace up nearly to the distant summit of that ma-

Ch, 1.) FALLS OF NIAGARA. 275

jestic cone which Pindar called “ the pillar of heaven,”
and which still continues to send forth a fleecy wreath
of vapour, reminding us that its fires are not extinct,
and that it may again give out a rocky stream, wherein
Other scenes like that now described may present them-
Selves to future observers.
Falls of Niagara.— The falls of Niagara afford a
magnificent example of the progressive excavation of
a deep valley in solid rock. That river flows from
Lake Erie to Lake Ontario, the former lake being
330 feet above the latter, and the distance between
them being thirty-two miles. On flowing out of the
upper lake, the river is almost on a level with its
banks’; so that, if it should rise perpendicularly eight
or ten feet, it would lay under water the adjacent flat
Country of Upper Canada on the West, and of the
State of New York onthe East.* The river, where it
issues, is about three quarters of a mile in width.
Before reaching the falls, it is propelled with great
rapidity, being a mile broad, about twenty-five feet
deep, and having a descent of fifty feet in half a mile.
An island at the very verge of the cataract divides it
into two sheets of water; one of these, called the
Horse-shoe Fall, is six hundred yards wide, and 158
feet perpendicular; the other, called the American
Falls, is about two hundred yards in width, and 164
feet in height. The breadth of the island is about
five hundred yards. This great sheet of water is pre-
Cipitated over a ledge of hard limestone, in horizontal
Strata, below which is a somewhat greater thickness
of soft shale, which decays and crumbles away more

. * Captain Hall’s Travels in North America, vol. i. p- 179.
N 6

276 FALLS OF NIAGARA, [Book IT:

rapidly, so that the calcareous rock forms an over-
hanging mass, projecting forty feet or more above the
hollow space below.

The blasts of wind, charged with spray, which rise
out of the pool into which this enormous cascade is
projected, strike against the shale beds, so that their
disintegration is constant ; and the superincumbent
limestone, being left without a foundation, falls from
time to time in rocky masses. When these enormous
fragments descend, a shock is felt at some distance;
accompanied by a noise like a distant clap of thunder:
After the river has passed over the falls, its character;
observes Captain Hall, is immediately and completely
changed. It then runs furiously along the bottom of
a deep wall-sided valley, or huge trench, which has
been cut into the horizontal strata by the continued
action of the stream during the lapse of ages. The
cliffs on both sides are in most places perpendicular,
and the ravine is only perceived on approaching the
edge of the precipice.*

The waters, which expand at the falls, where they
are divided by the island, are contracted again, after
their union, into a stream not more than 160 yards
broad. In the narrow channel, immediately below this
immense rush of water, a boat can pass across the
stream with ease. The pool, it is said, into which the
cataract is precipitated, being 170 feet deep, the de-
scending water sinks down and forms an under-current,
while a superficial eddy carries the upper stratum back
towards the main fall. This is not improbable ; and

* Hall’s Travels in North America, vol. i. pp- 195, 196. 216-
t See Mr. Bakewell, jun. on the falls of Niagara, with two
deseriptive drawings of the country between Lakes Erie and

Ch. 1.) FALLS OF NIAGARA, OTT

We must also suppose, that the confluence of the two
Streams, which meet at a considerable angle, tends
Mutually to neutralize their forces. The bed of the
“ver below the falls is strewed over with huge frag-
Ments which have been hurled down into the abyss.
By the continued destruction of the rocks, the falls
have, within the last forty years, receded nearly fifty
yards, or, in other words, the ravine has been prolonged
to.that extent. T hrough this deep chasm, the Niagara
flows for about seven miles ; and then the table-land,
Which is almost on a level with Lake Erie, suddenly
Sinks down at a town called Queenstown, and the river
“merges from the ravine into a plain, which continues
to the shores of Lake Ontario.

Recession of the Falls.— There seems good found-
ation for the general opinion, that the falls were once at
Queenstown, and that they have gradually retrograded
from that place to their present position, about seven
Miles distant. The table-land, extending from thence
to Lake Erie, consists uniformly of the same geological
formations as are now exposed to view at the falls. The
Upper stratum is an ancient alluvial sand, varying in
thickness from 10 to 140 feet ; below which is a bed
of hard limestone, about ninety. feet in thickness,
Stretching nearly in a horizontal direction over the
Whole country, and forming the bed of the river above
the falls, as do the inferior shales below. The lower
Shale is nearly of the same thickness as the limestone ;

Ut this last is said to thicken at the point now reached

Y the falls, a circumstance which may enable. it in

Ontario, including the Falls. — Loudon’s Mag. of Nat. Hist.
No. xii, March, 1830.

278 FALLS OF NIAGARA. [Book 1.

future to offer greater resistance to the force of the
cataract. *

If the ratio of recession had never exceeded fifty
yards in forty years, it must have required nearly te?
thousand years for the excavation of the whole ravine ;
but scarcely any estimate can be formed of the quan-
tity of time consumed in such an operation, because thé
retrograde movement was probably much more rapid
when the whole current was confined within a spacé
not exceeding a fourth or fifth of that which the falls
now occupy. Should the erosive action not be accele
rated in future, it will require upwards of thirty thou-
sand years for the falls to reach Lake Erie (twenty-fiv®
miles distant), to which they seem destined to arrivé
in the course of time, unless some earthquake change
the relative levels of the district.

If that great lake should remain in its present stat?
until the period when the ravine recedes to its shores
the sudden escape of so vast a body of water might
cause a tremendous deluge; for the ravine would bê
much more than sufficient to drain the whole lake, 0f
which the average depth was found, during the late
survey, to be only 10 or 12 fathoms. But, in conse’
quence of its shallowness, Lake Erie is fast filling UP
with sediment; and it may be questioned, whether it
entire area may not be converted into dry land, befor?
the falls recede so far.

* Monthly American Journ. July, 1831, p. 21.

CHAPTER II.
ACTION OF RUNNING WATER — continued,

Course of the Po — Desertion of its old channel — Artificial em.
bankments of the Po, Adige, and other Italian rivers ~ Basin
of the Mississippi — Its meanders — Islands — Shifting of its
course — Raftof the Atchafalaya (p. 286. )— Drift wood — New-
formed lakes in Louisiana — Earthquakes in valley of Missis-
sippi — Floods caused by land-slips in the White Mountains
(p. 293.) — Bursting of a lake in Switzerland — Devastations
caused by the Anio at Tivoli.

Course of the Po.—Tux Po affords an instructive

example of the manner in which a great river bears
down to the sea the matter poured into it by a multi-
tude of tributaries descending from lofty chains of
Mountains. The changes gradually effected in the
8reat plain of Northern Italy, since the time of the
Roman republic, are considerable. Extensive lakes
nd marshes have been gradually filled up, as those
Near Placentia, Parma, and Cremona, and many have
been drained naturally by the deepening of the beds
of rivers. Deserted river-courses are not unfrequent,
as that of the Serio Morto, which formerly fell into
the Adda, in Lombardy ; and the Po itself has often
deviated from its course. Subsequently to the year
1390, it deserted part of the territory of Cremona,
and invaded that of Parma; its old channel being still
recognizable, and bearing the name of Po Morto.
Bressello is one of the towns of which the site was
formerly on the left of the Po, but which is now on

280 EMBANKMENTS OF PO AND ADIGE. [Book II.

the right bank. There is also an old channel of the
Po in the territory of Parma, called Po Vecchio, which
was abandoned in the twelfth century, when a great
number of towns were destroyed. There are records
of parish churches, as those of Vicobellignano, Agojolo,
and Martignana, having been pulled down and after-
wards rebuilt at a greater distance from the devouring
stream. In the fifteenth’ century the main branch
again resumed its deserted channel, and carried away
a great island opposite Casalmaggiore. At the end of
the same century it abandoned, a second time, the
bed called “ Po Vecchio,” carrying away three streets
of Casalmaggiore. The friars in the monastery de
Serviti, took the alarm in 1471, demolished their build-
ings, and reconstructed them at Fontana, whither they
had transported the materials. In like manner, thé
church of S. Rocco was demolished in 1511. In the
seventeenth century also the Po shifted its course fot
a mile in the same district, causing great devastations-”

Artificial embankments of Italian rivers. —To check
these and similar aberrations, a general system of
embankment has been adopted; and the Po, Adige
and almost all their tributaries, are now confined
between high artificial banks. The increased velocity
acquired by streams thus closed in, enables them t°
convey a much larger portion of foreign matter to the
sea; and, consequently, the deltas of the Po and
Adige have gained far more rapidly on the Adriati¢
since the practice of embankment became almost
universal. But, although more sediment is borne t°
the sea, part of the sand and mud, which in thé

* Dell’ Antico Corso de’ Fiumi Po, Oglio, ed Adda, dell’ Ge
vanni Romani. Milan, 1828, i

Ch, 11,9 BASIN OF THE MISSISSIPPI. “ 281

Natural state of things would be spread out by annual
Nundations over the plain, now subsides in the bottom
of the river-channels ; and their capacity being thereby
iminished, it is necessary, in order to prevent in-
Undations in the following spring, to extract matter
ftom the bed, and to add it to the banks, of the river.
€nce it happens that these streams now traverse the
Plain on the top of high mounds, like the waters of
“qQueducts, and at Ferrara the surface of the Po has
"come more elevated than the roofs of the houses.*
he magnitude of these barriers is a subject of in-
“teasing expense and anxiety, it having been some-
times found necessary to give an additional height of
Nearly one foot to the banks of the Adige and Po ina
‘ingle season.

The practice of embankment was adopted on some
ofthe Italian rivers as early as the thirteenth century ;
d Dante, writing in the beginning of the fourteenth,
describes, in the seventh circle of hell, a rivulet of
tears separated from a burning sandy desert by em-

ankments “like those which, between Ghent and.

Tuges, were raised against the ocean, or those which
the Paduans had erected along the Brenta to defend
their villas on the melting of the Alpine snows.”

Quale i Fiamminghi tra Guzzante e Bruggia,
Temendo il fiotto che in ver lor s'avventa,
Fanno lo schermo, perchè il mar si fuggia,

E quale i Padovan lungo la Brenta,

Per difender lor ville e lor castelli,

Anzi che Chiarentana il caldo senta —

Inferno, Canto xv.
Basin of the Mississippi. — The hydrographical basin
of the Mississippi displays, on the grandest scale, the

* Prony, see Cuvier, Disc. Prélim. p. 146.

282 BASIN OF THE MISSISSIPPI. [Book J.

action of running water on the surface of a vast cor-
tinent. This magnificent river rises nearly in the forty-
ninth parallel of north latitude, and flows to the Gulf
of Mexico in the twenty-ninth —a course, including i
meanders, of nearly five thousand miles. It passes
from a cold arctic climate, traverses the temperate
regions, and discharges its waters into the sea in thé
region of the olive, the fig, and the sugar-cane.* No
river affords a more striking illustration of the Ja”
before mentioned, that an augmentation of volume does
not occasion a proportional increase of surface, nay, ®
even sometimes attended with a narrowing of th?
channel. The Mississippi is half a mile wide at i
junction with the Missouri +, the latter being also °
equal width ; yet the united waters have only, mei
their confluence to the mouth of the Ohio, a media
width of about three quarters of a mile. The juncti®®
of the Ohio seems also to produce no increase, but
rather a decrease, of surface.t The St. Francis, whites
Arkansas, and Red rivers, are also absorbed by tP?
main stream with scarcely any apparent increase of ##
width ; and, on arriving near the sea at New Orlea?®
it is somewhat less than half a mile wide. Its dept?
there is very variable, the greatest at high water being
168 feet. The mean rate at which the whole body °
water flows is variously estimated. According to som”
it does not exceed one mile an hour. §

* Flints Geography, vol. i. p. 21.

+ Flint says (vol. i. p. 140.) that, where the Mississippi rect”
the Missouri, it is a mile and a half wide, but, according tO nll
tain B. Hall, this is a great mistake. — Travels in North Amero”
vol. iii. p. 328.

ł Flint’s Geography, vol. i. p. 142. j

§ Halls Travels in North America, vol. iii. p. 330., wbo uei
Darby.

Ch. 11] CURVES OF THE MISSISSIPPI. 283

The alluvial plain of this great river is bounded
On the east and west by great ranges of mountains
Stretching along their respective oceans. Below the
junction of the Ohio, the plain is from thirty to fifty
miles broad, and after that point it goes on increasing
m width, till the expanse is perhaps three times as
8&reat! On the borders of this vast alluvial tract are
Perpendicular cliffs, or ‘ bluffs,” as they are called,
Sometimes three hundred feet or more in height, com-
Posed of limestone and other rocks, and often of allu-
vium. For a great distance the Mississippi washes the
astern “bluffs;’ and below the mouth of the Ohio,
Never once comes in contact with the western. The
Waters are thrown to the eastern side, because all the
large tributary rivers entering from the west, have
filled that side of the great valley with a sloping mass
of clay and sand. For this reason, the eastern bluffs
‘are continually undermined, and the Mississippi is
Slowly but incessantly progressing eastward.*

Curves of the Mississippi.— The river traverses the
Plain in a meandering course, describing immense and
Uniform curves. After sweeping round the half of a
Circle, it is carried in a rapid current diagonally across
lts own channel, to another curve of the same uni-
formity upon the opposite shore. t These curves are
So regular, that the boatmen and Indians calculate
distances by them. Opposite to each of them there
ig always a sand-bar, answering, in the convexity of
its form, to the concavity of “the bend,” as it is
called. The river, by continually wearing these

* Geograph. Descrip. of the State of Louisiana, by W- pees
Philadelphia, 1816, p. 102. <
t Flint’s Geog. vol. i. p. 152. pe

284 TRANSPORTATION OF MATTER [Book 13.

curves deeper, returns, like many other streams before
described, on its own tract, so that a vessel in somé
places, after sailing for twenty-five or thirty miles, i$
brought round again to within a mile of the place
whence it started. When the waters approach 50
near to each other, it often happens at high floods
that they burst through the small tongue of land, and
insulate a portion, rushing through what is called thé
“ cut off” with great velocity. At one spot, called
the “grand cut off,” vessels now ‘pass from one point
to another in half a mile to a distance which it formerly
required a voyage of twenty miles to reach.*

Waste of its banks. — After the flood season, whet
the river subsides within its channel, it acts with
destructive force upon the alluvial banks, softened
and diluted by the recent overflow. Several acres at?
time, thickly covered with wood, are precipitated int?
the stream ; and large portions of the islands formed
by the process before described are swept away.

“Some years ago,” observes Captain Hall, « whe?
the Mississippi was regularly surveyed, all its islands
were numbered, from the confluence of the Missou™
to the sea; but every season makes such. revolution
not only in the number but in the magnitude and
situation of these islands, that this enumeration ®
now almost obsolete. Sometimes large islands a"?
entirely melted away—at other places they -havé
attached themselves to the main shore, or, which !5
the more correct statement, the interval has bee
filled up by myriads of logs cemented together by
mud and rubbish.” + When the Mississippi and mary

* Flints Geog. vol. i. p: 154.
t Travels in North America, vol. iii, p. 361.

Ch. 11,] BY THE MISSISSIPPL 285 ©

of its great tributaries overflow their banks, the waters,

eing no longer borne down by the main current, and

€coming impeded amongst the trees and bushes,
deposit the sediment of mud and sand with which
they are abundantly charged. Islands arrest the pro-
stess of floating trees, and they often become in this
Manner reunited to the land; the rafts of trees, together
With mud, constituting at length a solid mass. The
Coarser and more sandy portion is thrown down first
Nearest the banks; and finer particles are deposited at
the farthest distances from the river, where an im-
Palpable mixture subsides, forming a stiff unctuous
black soil. Hence, in the alluvial plains of these rivers
the land slopes back, like-a natural glacis towards the

cliffs bounding the great valley (see fig. 9.), and during
Fig. 9.
IB

eee ie he 1 ee i sete ae tae

a, Channel of the river. b, Base of the “ bluffs.”
inundations the highest part of the banks form narrow
Strips of dry ground; rising above the river on one
Side, and above the low flooded country on the other.
The Mississippi therefore has been described as a
tiver running on the top of a long hill or ridge, which
has an elevation of twenty-four feet in its highest part, -
and a base three miles in average diameter. Flint,
however, remarks, that this picture is not very cor-
rect, for, notwithstanding the comparative elevation of
the banks, the deepest part of the bed of the river
(a, fig. 9.) is uniformly lower than the lowest point of
the alluvium at the base of the bluffs.*

It has been said of a mountain torrent that “ it lays
down what it will remove, and removes what it has
laid down ;” and in like manner the Mississippi, by the

* Flints Geography, vol. i. p. 151.

286 RAFT OF THE ATCHAFALAYA. [Book JI.

continual shifting of its course, sweeps away, during 4
great portion of the year, considerable tracts of alluvium
which were gradually accumulated by the overflow of
former years, and the matter now left during the spring-
floods will be at some future time removed.

Raft of the Atchafalaya.— One of the most interest-
ing features in this basin is “ the raft.” The dimen-
sions of this mass of timber were given by Darby, i£
1816, as ten miles in length, about 220 yards wide,
and eight feet deep, the whole of which had accu-
mulated in consequence of some obstruction, during
about thirty-eight years, in an arm of the Mississippi
called the Atchafalaya, which is supposed to have
been at some past time a channel of the Red River
before it intermingled its waters with the mail
stream. This arm is in a direct line with the general
course of the Mississippi, and it catches a large por-
tion of the drift wood annually brought down.

The mass of timber in the raft is continually in-
creasing, and the whole rises:and falls with the water-
Although floating it is covered with green bushes
like a tract of solid land, and its surface is enlivened
in the autumn by a variety of beautiful flowers.

The rafts on Red River are equally remarkable ; i
some parts of its course, cedar trees are heaped up by
themselves, and in other places pines. There is als?
a raft on the Washita, the principal tributary of the
Red River, which seriously interrupts the navigation,
concealing the whole river for seventeen leagues:
This natural bridge is described in 1804 as supporting
all the plants then growing in the neighbouring forests
not excepting large trees; and so perfectly was the
stream concealed by the superincumbent mass, that 1t

Ch, 17) DRIFT WOOD. 287

Might be crossed in some places without any knowledge
of its existence.*

Drift Wood. — Notwithstanding the astonishing
‘umber of cubic feet of timber arrested by the rafts,
Steat deposits are unceasingly in progress at the ex-
Temity of the delta in the Bay of Mexico. “ Unfor-
tunately for the navigation of the Mississippi,” observes

4ptain Hall, «some of the largest trunks, after being
“ast down from the position on which they grew, get

eir roots entangled with the bottom of the river,
Where they remain anchored, as it were, in the mud,

he force of the current naturally gives their tops a
“ndency downwards, and, by its flowing past, soon
“tips them of their leaves and branches. These

Xtures, called snags or planters, are extremely dan-
Stous to the steam-vessels proceeding up the stream,
" which they lie like a lance in rest, concealed. be-

Neath the water, with their sharp ends pointed directly
Bainst the bow of the vessels coming up. For the
Most part, these formidable snags remain so still, that

€Y can be detected only by a slight ripple above
them, not perceptible to inexperienced eyes. Some-
mes, however, they vibrate up and down, alternately
wing their heads above the surface and bathing
m beneath it.”+ So imminent is the danger caused
y these obstructions, that almost all the boats on the
'Ssissippi are constructed on a particular plan, to
Suard against fatal accidents. |

Navigator, p- 263. Pittsburgh, 1821.
Travels in North America, vol. iii. p. 362. :
alleq The boats are fitted,” says Captain Hall, “ with "i
is os Snag-chamber ; — a partition formed! of stout planks, os a

ed, and made so effectually water-tight, that the fore
of the vessel is cut off as entirely from the rest of the hold as

988 DRIFT WOOD OF THE MISSISSIPPI. [Book I

The prodigious quantity of wood annually drifted
down by the Mississippi and its tributaries, is a subje®!
of geological interest, not merely as illustrating the
manner in which abundance of vegetable matter be-
comes, in the ordinary course of nature, imbedded
submarine and estuary deposits, but as attesting thé
constant destruction of soil and transportation of mat
ter to lower levels by the tendency of rivers to shift
their courses. Each of these trees must have require
many years, some of them many centuries, to atta
their full size ; the soil, therefore, whereon they grew
after remaining undisturbed for long periods, is ut”
mately torn up and swept away. Yet, nofwithstao”
ing this incessant destruction of land and up-rooting °
trees, the region which yields this never-failing supp
of drift wood is densely clothed with noble forest®
and is almost unrivalled in its power of supporti9s
animal and vegetable life.

Innumerable herds of wild deer and bisons feed ™
the luxurious pastures of the plains. The jaguar; the
wolf, and the fox, are amongst the beasts of prey-
waters teem with alligators and tortoises, and t!
surface is covered with millions of migratory water
fowl, which perform their annual voyage between the
Canadian lakes and the shores of the Mexican GU”
The power of man begins to be sensibly felt, and the
wilderness to be replaced by towns, orchards, ji
gardens. The gilded steam-boat, like a moving ©’
now stems the current with a steady peace—??

eit

if it belonged to another boat. If the steam-vessel happen t° we
against a snag, and that a hole is made in her bow, under the 5”
face, this chamber merely fills with water.” Travels in Nott
America, vol. iii. p. 363.

Ch. 11] DRIFT WOOD OF THE MISSISSIPPI. 289

shoots rapidly down the descending stream through
the solitudes of the forests and prairies. Already
does the flourishing population of the great valley ex-
Ceed that of the thirteen United States when first
they declared their independence, and, after a san-
Suinary struggle, were severed from the parent
Country.* Such is the state of a continent where
rocks and trees are hurried annually, by a thousand
torrents, from the mountains to the plains, and where
Sand and finer matter are swept down by a vast cur-
Tent to the sea, together with the wreck of countless
forests and the bones of animals which perish in the
inundations. When these materials reach the Gulf,
they do not render the waters unfit for aquatic ani-
mals ; but, on the contrary, the ocean here swarms
With life, as it generally does where the influx of a
Sreat river furnishes a copious supply of organic and
Mineral matter. Yet many geologists, when they
behold the spoils of the land heaped in successive
Strata, and blended confusedly with the remains of
fishes, or interspersed with broken shells and corals, -
imagine that they are viewing the signs of a turbulent
Instead of a tranquil and settled state of the planet.
They read in such phenomena the proof of chaotic
disorder, and reiterated catastrophes, instead of indi-
Cations of a surface as habitable as the most delicious
and fertile districts now tenanted by man. They are
Not content with disregarding the analogy of the
Present course of Nature, when they speculate on the
revolutions of past times, but they often draw conclu-
sions, concerning the former state of things, directly
the reverse of those to which a fair induction from
facts would infallibly lead them.
* Flint’s Geography, vol. i.
VOL. I. (0)

990 NEW LAKES IN LOUISIANA. [Book I.

Formation of lakes in Louisiana.— Another striking
feature in the basin of the Mississippi, illustrative of
the changes now in progress, is the formation by
natural causes of great lakes, and the drainage of
others. These are especially frequent in the basin of
the Red River in Louisiana, where the largest of
them, called Bistineau, is more than thirty miles long;
and has a medium depth of from fifteen to twenty feet.
In the deepest parts are seen numerous cypress trees;
of all sizes, now dead, and most of them with their
tops broken by the wind, yet standing erect undet
water. ‘This tree resists the action of air and water
longer than any other, and, if not submerged through-
out the whole year, will retain life for an extraordinary
period.* Lake Bistineau, as well as Black Lake,
Cado Lake, Spanish Lake, Natchitoches Lake, and
many others, have been formed, according to Darby;
by the gradual elevation of the bed of Red River, i?
which the alluvial accumulations have been so great
as to raise its channel, and cause its waters, during
_ the flood season, to flow up the mouths of many tribu-
taries, and to convert parts of their courses into lakes-
In the autumn, when the level of Red River is again
depressed, the waters rush back again, and some lakes
become grassy meadows, with streams meandering
through them.+ Thus, there is a periodical flux and
reflux between Red River and some of these basins
which are merely reservoirs, alternately emptied and

* Captains Clark and Lewis found a forest of pines standing
erect under water in the body of the Columbia River in Nort?
America, which they supposed, from the appearance of the trees,
to have been submerged only about twenty years. — Vol. ii.
p. 241.

+ Darby’s Louisiana, p. 33.

Ch. 11] BASIN OF MISSISSIPPI. 291

filled like our tide estuaries—with this difference,
that in the one case the land is submerged for several
Months continuously, and, in the other, twice in every
twenty-four hours. It has happened, in several cases,
thata bar has been thrown by Red River across some
of the openings of these channels, and then the lakes

€come, like Bistineau, constant repositories of water.
But even in these cases, their level is liable to annual
elevation and depression, because the fleod of the main
tiver, when at its height, passes over the bar ; just as,
Where sand-hills close the entrance of an estuary on
the Norfolk or Suffolk coast, the sea, during some high
tide or storm, has often breached the barrier and inun-
dated again the interior.

Earthquakes in basin of Mississippi.— The frequent
fluctuations in river courses, in various parts of the
basin of the Mississippi, are partly, perhaps, to be
äscribed to the co-operation of subterranean move-
ments, which alter from time to time the relative
levels of various parts of the surface. So late as the
year 1812, the whole valley from the mouth of the
Ohio to that of the St. Francis, including a tract three

Undred miles in length, and exceeding in area the
Whole basin of the Thames, was convulsed to such a
degree, as to create new islands in the river, and lakes
n the alluvial plain, some of which were twenty miles
i extent. I shall allude to this event, by which New

adrid was in great part destroyed, when I treat of
“arthquakes ; but may state here, that it happened
“Xactly at the same time as the fatal convulsions in the
istrict of Caraccas; and the country shaken was
Nearly five degrees of latitude farther removed from
the great centre of volcanic disturbance, than the
basin of the Red River before alluded to. Darby
o 2

\

992 > FLOODS, BURSTING OF LAKES, ETC. [Book Il-

mentions beds of marine shells on the banks of Red
River, which seem to indicate that Lower Louisiana
is of recent formation: its elevation, perhaps, above
the sea, may have been due to the same series of
earthquakes which continues to agitate equatorial
America.

When countries are liable to be so extensively and
permanently affected by earthquakes, speculations con-
cerning changes in their hydrographical features must
not be made without regard to the igneous as well a$
the aqueous causes of change. It is scarcely neces
sary to observe, that the inequalities produced even by
one shock might render the study of the alluvial plain
of the Mississippi, at some future period, most per
plexing to a geologist who should reason on the dis-
tribution of transported materials, without being aware
that the configuration of the country had varied mate-

rially during the time when the excavating or removing
power of the river was greatest.

FLOODS, BURSTING OF LAKES, ETC.

The power which running water may exert, in thé
lapse of ages, in widening and deepening a valley, doe
not so much depend on the volume and velocity of thé
stream usually flowing in it, as on the number a?
magnitude of the obstructions which have, at differen!
periods, opposed its free passage. If a torrent, how-
ever small, be effectually dammed up, the size of thé
valley above the barrier, and its declivity below, a”
not the dimensions of the torrent, will determine thé
violence of the débâcle. The most universal source °
local deluges are landslips, slides, or avalanches, *°
they are sometimes called, when great masses of rock

Ch. IL] FLOODS IN NORTH AMERICA. 293

and soil, or sometimes ice and snow, are precipitated
Into the bed of a river, the boundary cliffs of which
have been thrown down by the shock of an earthquake,
or undermined by springs or other causes. Volumes
might be filled with the enumeration of instances on
record of these terrific catastrophes: I shall therefore
Select a few examples of recent occurrence, the facts
of which are well authenticated. l

Floods caused by landslips, 1826.— Two dry seasons
in the White Mountains, in New Hampshire, were fol-
lowed by heavy rains on the 28th August, 1826, when
from the steep and lofty declivities which rise abruptly
on both sides of the river Saco innumerable rocks and
Stones, many of sufficient size to fill a common apart-
Ment, were detached, and in:their descent swept down
before them, in one promiscuous and frightful ruin,
forests, shrubs, and the earth which sustained them.
No tradition existed of any similar slides at former
times, and the growth of the forest on the flanks of the
hills clearly showed that for a long interval nothing
Similar had occurred. One of these moving masses
was afterwards found to have slid three miles, with an
average breadth of a quarter of a mile. The natural
excavations commenced generally in a trench a few
yards in depth and a few rods in width, and descended
the mountains, widening and deepening till they be-
Came vast chasms. At the base of these hollow
ravines was seen a wide and deep mass of ruins, con-
Sisting of transported earth, gravel, rocks, and trees.
Forests of spruce-fir and hemlock were prostrated with
as much ease as if they had been fields of grain ; for,
where they disputed the ground, the torrent of mud
and rock accumulated behind till it gathered sufficient.
force to burst the temporary barrier.

0S

204. FLOODS IN NORTH AMERICA. [Book If.

The valleys of the Amonoosuck and Saco presented,
for many miles, an uninterrupted scene of desolation;
all the bridges being carried away, as well as those
over their tributary streams. In some places, the road
was excavated to the depth of from fifteen to twenty
feet; in others, it was covered with earth, rocks, and
trees, to as great a height. The water flowed for
many weeks after the flood, as densely charged with
earth as it could be without being changed into mud,
and marks were seen in various localities of its having
risen on either side of the valley to more than twenty-
five feet above its ordinary level. Many sheep and
cattle were swept away, and the Willey family, nine
in number, who in alarm had deserted their house;
were destroyed on the banks of the Saco; seven of
their mangled bodies were afterwards found near the
river, buried beneath drift wood and mountain ruins.*
The geologist should remark that the lower alluvial
plains are most exposed to such violent floods, and
at the same time are best fitted for the sustenance of
herbivorous animals. If, therefore, any organic re-
mains are found amidst the superficial heaps of trans-
ported matter, resulting from those catastrophes, at
whatever periods they may have happened, and what-
ever may have been the former configuration and relative
levels of the country, we may expect the imbedded
fossil relics to be principally referable to this class of
mammalia. i

But these catastrophes are insignificant, when com-
pared to those which are occasioned by earthquakes
when the boundary hills, for miles in length, are
thrown down into the hollow of a valley. I shall have

* Silliman’s Journal, vol. xy. No. 2, p.216. Jan, 1829.

Che IL] FLOOD IN THE VALLEY OF BAGNES. 295

Opportunities of alluding to inundations of this kind
when treating expressly of earthquakes, and shall con-
tent myself at present with selecting an example, of
modern date, of a flood eaused by the bursting of a
temporary lake ; the facts having been described, with
more than usual accuracy, by scientific observers.
Flood in the Valley of Bagnes, 1818.— The valley
of Bagnes is one of the largest of the lateral embranch-
ments of the main valley of the Rhone, above the
Lake of Geneva. Its upper portion was, in 1818,
converted into a lake by the damming up of a nar-
row pass, by avalanches of snow and ice, precipitated
from an elevated glacier into the bed of the river
Dranse. In the winter season, during continued frost,
scarcely any water flows in the bed of this river to
preserve an open channel, so that the ice barrier re-
mained entire until the melting of the snows in spring,
when a lake was formed above, about half a league
in length, which finally attained in some parts a
depth of about two hundred feet, and a width of
about seven hundred feet. To prevent or lessen the
mischief apprehended from the sudden bursting of the
barrier, an artificial gallery, seven hundred feet in
length, was cut through the ice, before the waters had
risen to a great height. When at length they accu-
mulated and flowed through this tunnel, they dissolved
the ice, and thus deepened their channel, until nearly
half of the whole contents of the lake were slowly
drained off. But, at length, on the approach of the
hot season, the central portion of the remaining mass
of ice gave way with a tremendous crash, and the
residue of the lake was emptied in half an hour. In
the course of its descent, the waters encountered
o 4

296 BURSTING. OF A LAKE [Book Il.

several narrow gorges, and at each of these they rose
to a great height, and then burst with new violence
into the next basin, sweeping along rocks, forests,
houses, bridges, and cultivated land. For the greater
part of its course the flood resembled a moving mass
of rock and mud, rather than of water. Some frag-
ments of granitic rocks, of enormous magnitude, and
which, from their dimensions, might be compared
without exaggeration to houses, were torn out of a
more ancient alluvion, and borne down for a quarter
of a mile. One of the fragments moved was sixty
paces in circumference.* The velocity of the water,
in the first part of its course, was thirty-three feet per
second, which diminished to six feet before it reached
the Lake of Geneva, where it arrived in six hours and
a half, the distance being forty-five miles. +

This flood left behind it, on the plains of Martigny,
thousands of trees torn up by the roots, together with
the ruins of buildings. Some of the houses in that
town were filled with mud up to the second story-
After expanding in the plain of Martigny, it entered
the Rhone and did no further damage ; but some
bodies of men, who had been drowned above Martigny,
were afterwards found, at the distance of about thirty
miles, floating on the farther side of the Lake of
Geneva, near Vevey.

The waters, on escaping from the temporary lake,
intermixed with mud and rock, swept along, for the first
four miles, at the rate of above twenty miles an hour;

* This block was measured by Capt. B. Hall, R. N.

t See an account of the inundation of the Val de Bagnes, in
1818, in Ed. Phil. Journ., vol, i, p, 187., drawn up from the
Memoir of M. Escher, with a section, &c.

Ch. 11.7 IN THE VALLEY OF BAGNES. 297

and M. Escher, the engineer, calculated that the flood
furnished 300,000 cubic feet of water every second
—an efflux which is five times greater than that of
the Rhine below Basle. Now, if part of the lake
had not been gradually drained off, the flood would
have been nearly double, approaching in volume to
Some of the largest rivers in Europe. It is evident,
therefore, that, when we are speculating on the exca-
Yating force which a river may have exerted in any
Particular valley, the most important question is, not
the volume of the existing stream, nor the present
levels of its channel, nor even the nature of the rocks,
but the probability of a succession of floods, at some
Period since the time when the valley may have been
first elevated above the sea.

For several months after the débâcle of 1818, the
Dranse, having no settled channel, shifted its position
Continually from one side to the other of the valley,
Carrying away newly erected bridges, undermining

Ouses, and continuing to be charged with as large a
quantity of earthy matter as the fluid could hold in
Suspension. I visited this valley four months after the
flood, and was witness to the sweeping away of a
bridge, and the undermining of part of a house. The
greater part of the ice-barrier was then standing, pre-
Senting vertical cliffs 150 feet high, like ravines in the
lava-currents of Etna or Auvergne, where they are
mtersected by rivers.

Inundations, precisely similar, are recorded to have
Occurred at former periods in this district, and from
the same cause. In 1595, for example, a lake’ burst,
and the waters, descending with irresistible fury; de-
Stroyed the town of Martigny, where from sixty to

m

0 p

298 . FLOOD OF THE ANIO AT TIVOL Book II,

eighty persons perished. In a similar flood, fifty
years before, 140 persons were drowned.

Flood at Tivoli, 1826.—I shall conclude with one
more example, derived from a land of classic recollec- i
tions, the ancient Tibur, and which, like all the other
inundations above alluded to, occurred within the pre-
sent century. The younger Pliny, it will be remem-
bered, describes a flood on the Anio, which destroyed
woods, rocks, and houses, with the most sumptuous
villas and works of art.* For four or five centuries
consecutively, this “headlong stream,” as Horace
truly called it, has often remained within its bounds
and then, after so long an interval of rest, has at dif-
ferent periods inundated its banks again, and widened
its channel. The last of these catastrophes happened
15th Nov. 1826, after heavy rains, such as produced
the floods before alluded to in Scotland. The waters
appear also to have been impeded by an artificial dike;
by which they were separated into two parts, a short
distance above Tivoli. They broke through this dike;
and, leaving the left trench dry, precipitated them-
selves, with their whole weight, on the right side.
Here they undermined, in the course of a few hours;
a high cliff, and widened the river’s channel about
fifteen paces. On this height stood the church of St:
Lucia, and about thirty-six houses of the town of
Tivoli, which were all carried away, presenting, 48
they sank into the roaring flood, a terrific scene 0
destruction to the spectators on the opposite bank.
As the foundations were gradually removed, each
building, some of them edifices of considerable height;

* Lib. viii. Epist. 17.

Ch. ILJ FLOOD OF THE ANIO AT TIVOLI. 299

was first traversed with numerous rents, which soon
widened into large fissures, until at length the roofs
fell in with a crash, and then the walls sank into the
river, and were hurled down the cataract below.*

The destroying agency of the flood came within
two hundred yards of the precipice on which the
beautiful temple of Vesta stands; but fortunately this
precious relic of antiquity was spared, while the wreck
of modern structures was hurled down the abyss.
Vesta, it will be remembered, in the heathen mytho-
logy, personified the stability of the earth ; and when
the Samian astronomer, Aristarchus, first taught that
the earth revolved on its axis, and round the sun, he
was publicly accused of impiety, “ for moving the
everlasting Vesta from her place.” Playfair observed,
that when Hutton ascribed instability to the earth’s
surface, and represented the continents which we
inhabit as the theatre of incessant change and move-
ment, his antagonists, who regarded them as un-
alterable, assailed him in a similar manner, with
accusations founded on religious prejudices.; We
might appeal to the excavating power of the Anio as
corroborative of one of the most controverted parts
of the Huttonian theory; and if the days of omens
had not gone by, the geologists who now worship
Vesta might regard the late catastrophe as portentous.
We may, at least, recommend the modern votaries of
the goddess to lose no time in making a pilgrimage to
her shrine, for the next flood may not respect the
temple.

* When at Tivoli, in 1829, I received this account from eye-
witnesses of the event.
+ Illustr. of Hutt. Theory, § 3. p. 147.

o 6

CHAPTER III.
PHENOMENA OF SPRINGS.

Origin of Springs — Bored wells — Distinct causes by which
mineral and thermal waters may be raised to the surface —
Their connection with volcanic agency (p. 308.) — Calcareous
Springs — Travertin of the Elsa — Baths of San Vignone and
of San Filippo, near Radicofani — Spheroidal structure in tra-
vertin, as in English magnesian limestone (p..317.) — Bulicami
of Viterbo — Lake of the Solfatara, near Rome — Travertin at
Cascade of Tivoli (p. 322.) — Gypseous, Siliceous, and Ferru-
ginous Springs — Brine Springs (p. 330.) — Carbonated
Springs — Disintegration of granite in Auvergne — Petroleum
Springs — Pitch Lake of Trinidad.

Origin of springs. —Tur action of running water on
the land having been considered, we may next turn
our attention to what may be termed “ the subter-
ranean drainage,” or the phenomena of springs. Every
one is familiar with the fact, that certain porous soils,
such as loose sand and gravel, absorb water with rapi-
dity ; and that the ground composed of them soon dries
up after heavy showers. If a well be sunk in such
soils, we often penetrate to considerable depths before
we meet with water ; but this is usually found on our
approaching the lower parts of the formation, where it
rests on some impervious bed; for here the water,
unable to make its way downwards in a direct line,
accumulates as in a reservoir, and is ready to ooze out
into any opening which may be made, in the same
manner as we see the salt water flow into, and fill,

Ch, 111.7 ORIGIN OF SPRINGS. 301

any hollow which we dig in the sands of the shore at
low tide.

The facility with which water can percolate loose
and gravelly soils is clearly illustrated by the effect of
the tides in the Thames between Richmond and

Ondon. The river, in this part of its course, flows
through a bed of gravel overlying clay, and the porous
SUperstratum is alternately saturated by the water of
the Thames as the tide rises, and then drained again
to the distance of several hundred feet from the banks
Vhen the tide falls, so that the wells in this tract regu-
larly ebb and flow.

If the transmission of water through a porous
Medium be so rapid, we cannot be surprised that
Springs should be thrown out on the side of a hill,
Where the upper set of strata consist of chalk, sand, or
ther permeable substances, while the subjacent are
“omposed of clay or other retentive soils. The only

ifficulty, indeed, is, to explain, why the water does
ot ooze out every where along the line of junction of
the two formations, so as to form one continuous land-
Soak, instead of a few springs only, and these far dis-
tant from each other. The principal cause of this
“Oncentration of the waters at a few points is, first, the
"equency of rents and fissures, which act as natural
rains ; secondly the existence of inequalities in the
Upper surface of the impermeable stratum, which lead
the water, as valleys do on the external surface of a
Country, into certain low levels and channels.

That the generality of springs owe their supply to
the atmosphere is evident from this, that they become
‘nguid, or entirely cease to flow, after long droughts,
and are again replenished after a continuance of rain.

any of them are probably indebted for the constancy

302 ORIGIN OF SPRINGS. [Book 1}

and uniformity of their volume to the great extent of
the subterranean reservoirs with which they commu-
nicate, and the time required for these to empty them-
selves by percolation. Such a gradual and regulated
discharge is exhibited, though in a less perfect degre®
in every great lake which is not sensibly affected 1
its level by-sudden showers, but only slightly raised:
so that its channel of efflux, instead of being swo
suddenly like the bed of a torrent, is enabled to catty
off the surplus water gradually.

Much light has been thrown, of late years, on thé
theory of springs, by the boring of what are called bY
the French “ Artesian wells,” because the method has
long been known and practised in Artois; and it #8
now demonstrated that there are sheets, and, in somé
places, currents of fresh water, at various depths in the
earth. The instrument employed in excavating thes?
wells is a large auger, and the cavity bored is usually
from three to four inches in diameter. If a hard rock
is met with, it is first triturated by an iron rod, a?
the materials, being thus reduced to small fragment? .
or powder, are readily extracted. To hinder the sides
of the well from falling in, as also to prevent thé
spreading of the ascending water in the surrounding
soil, a jointed pipe is introduced, formed of wood #
Artois, but in other countries more commonly of metal:
It frequently happens that, after passing through hu”
dreds of feet of retentive soils, a water-bearing stratu
is at length pierced, when the fluid immediately ascends
to the surface and flows over. The first rush of th?
water up the tube is often violent, so that for a tim?
the water plays like a fountain, and then, sinking, CO?”
tinues to flow over tranquilly, or sometimes remains St
tionary at a certain depth below the orifice of the wel!

Ch. 111.) ORIGIN OF SPRINGS. 303

This spouting of the water in the first instance is pro-
bably owing to the disengagement of air and carbonic
acid gas, for both of these have been seen to bubble
up with the water.* i

At Sheerness, at the mouth of the Thames, a well
was bored on a low tongue of land near the sea, through
300 feet of the blue clay of London, below which a
bed of sand and pebbles was entered, belonging, doubt-
less, to the plastic clay formation: when this stratum
was pierced, the water burst up with impetuosity, and
filled the well. By another perforation at the same
Place, the water was found at the depth of 328 feet,
below the surface clay ; it first rose rapidly to the
height of 189 feet, and then, in the course of a few
hours, ascended to an elevation of eight feet above the
level of the ground. In 1824, a well was dug at Fulham,
Near the Thames, at the Bishop of London’s, to the
depth of 317 feet, which, after traversing the tertiary
Strata, was continued through 67 feet of chalk. The
Water immediately rose to the surface, and the dis-
Charge was above 50 gallons per minute. In the
garden of the Horticultural Society at Chiswick, the
borings passed through 19 feet of gravel, 242 feet of
clay and loam, and 67 feet of chalk, and the water then
Tose to the surface from a depth of 329 feet.t At the
Duke of Northumberland’s, above Chiswick, the borings
Were carried to the extraordinary depth of 620 feet,
SO as to enter the chalk, when a considerable volume
of water was obtained, which rose four feet above the
Surface of the ground. In a well of Mr. Brooks, at
Hammersmith, the rush of water from a depth of 360

* Consult Héricart de Thury’s work on “ Puits Forés.”
t Sabine, Journ, of Sci., No. 33. p. 72. 1824.

304 ORIGIN OF SPRINGS. [Book II.

feet was so great, as to inundate several buildings and
do considerable damage ; and at Tooting, a sufficient
stream was obtained to turn a wheel, and raise the
water to the upper stories of the houses.* In the last
of three wells bored through the chalk, at Tours, to
the depth of several hundred feet, the water rose thirty-
two feet above the level of the soil, and the discharge
amounted to three hundred cubic yards of water every
twenty-four hours. +

Excavations have been made in the same way to the
depth of eight hundred, and even twelve hundred feet in
France (the latter at Toulouse), and without success. $
A similar failure was experienced in 1830, in boring at
Calcutta, to the depth of more than 150 feet, through
the alluvial clay and sands of Bengal. Mr. Briggs;
the British consul in Egypt, obtained water between
Cairo and Suez, in a calcareous sand, at the depth of
thirty feet ; but it did not rise in the well.§ The
geological structure of the Sahara is supposed, by M.
Rozet, to favour the prospect of a supply of water from
Artesian wells, as the parched sands on the outskirts of
the desert rest on a substratum of argillaceous marl.||

The rise and overflow of the water in these wells is
generally referred, and apparently with reason, to the
same principle as the play of an artificial fountain-
Let the porous stratum, or set of strata aa, rest. op
_ the impermeable rock d, and be covered by another

mass of an impermeable nature. The whole mass a 4
may easily, in such a position, become saturated with

* Héricart de Thury, p. 49.

+ Bull. de la Soc. Géol. de France, tom. iii. p. 194.

+ dd. tom. il. p. 272:

§ Boué, Résumé des Prog. de la Géol. en 1832, p. 184.
|| Bull. dela Soc. Géol. de France, tom. ii. p. 364.

Ch. 111] : ORIGIN OF SPRINGS. 305

Water, which may descend from its higher and exposed
Parts—a hilly region to which clouds are attracted,

SSE s 7 ai
A l

d where rain falls in abundance. sail that at
Some point, as at b, an opening be made which gives
à free passage upwards to the waters confined ina a
àt so low a level that they are subjected to the pres-
‘ure of a considerable column of water collected in
the more elevated portion of the same stratum. The
Water will then rush out, just as the liquid from a
arge barrel which is tapped, and it will rise to a
fight corresponding to the level of its point of de-
Parture, or, rather, to a height which balances the pres-
Sure previously exerted by the confined waters against
the roof and sides of the stratum or reservoiraa. In
ike manner, if there happen to be a natural fissure c,
“spring will be produced at the surface on precisely

€ same principle.

Among the causes of the failure of artesian wells,
we may mention. those numerous rents and faults
Which abound in some rocks, and the deep ravines

and valleys by which many countries are traversed ;
r, when these natural lines of drainage exist, there
*emains a small quantity only of water to escape by
artificial issues. We are alse liable to be baffled by the
Sreat thickness either of porous or impervious strata,
or by the dip of the beds, which may carry off the
Waters from adjoining high lands, to some trough in an

306 ORIGIN OF SPRINGS, [Book 1:

opposite direction ; as when the borings are made a
the foot of an escarpment where the strata incliné
inwards, or in a direction opposite to the face of thé
cliffs.

The mere distance of hills or mountains need n%
discourage us from making trials ; for the waters whic!
fall on these higher lands readily penetrate to great
depths through highly inclined or vertical strata, 0
through the fissures of shattered rocks, and after flow
ing for a great distance, must often re-ascend and be
brought up again by other fissures, so as to approach
the surface in the lower country. Here they may be
concealed beneath a covering of undisturbed horizonté
beds, which it may be necessary to pierce in order
reach them. It should be remembered, that the cours?
of waters flowing under ground bears but a remot?
resemblance to that of rivers on the surface, thet
being, in the one Case, a constant descent froma high
to a lower level from the source of the stream to thé
sea ; whereas, in the other, the water may at one tim?
sink far below the level of the ocean, and afterwaré
rise again high above it.

Among other curious facts ascertained by aid of
the borer, it is proved that in strata of different ag%
and compositions there are often open passages DY
which the subterranean waters circulate. Thus, #
St. Ouen, in France, five distinct sheets of water wel?
intersected in a well, and from each of these a supply
obtained. In the third water-bearing stratum, hi
the depth of 150 feet, a cavity was found in which
the borer fell suddenly about a foot, and thence thé
water ascended in great volume.* The same falling °

* H. de Thury, p. 295."

|

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Ch, 111,] ORIGIN OF SPRINGS. 307

the instrument, as in a hollow space, has been remarked
m England and other countries. At Tours, in 1830,
à well was perforated quite through the chalk, when
the water suddenly brought up, from a depth of 364
feet, a great quantity of fine sand, with much vegetable
Matter and shells. Branches of a thorn several inches
long, much blackened by their stay in the water, were
tecognized, as also the stems of marsh plants, and
Some of their roots, which were still white, together
With the seeds of the same, in a state of preservation
Which showed that they had not remained more than
three or four months in the water. Among the seeds
Were those of the marsh-plant Galium uliginosum ;
and among the shells, a freshwater species (Planorbis
marginatus), and. some land species, as Helix rotundata
ad H. striata. M. Dujardin, who, with others, ob-
Served this phenomenon, supposes that the waters had

flowed from some valleys of Auvergne or the Vivarais

Since the preceding autumn.*

An analogous phenomenon is recorded at Riemke,
Near Bochum in Westphalia, where the water of an
artesian well brought up, from a depth of 156 feet,
Several small fish, three or four inches long, the nearest
Streams in the country being at the distance of some
leagues.+

In both cases it is evident that water had pene-
trated to great depths, not simply by filtering through
a porous mass, for then it would have left behind the
Shells, fish, and fragments of plants, but by flowing
through some open channels in the earth. Such ex-
amples may suggest the idea that the leaky beds of
"Ivers are often the feeders of springs.

* Bull. de la Soc. Géol. de France, tom. i. pe 95:
t+ Id. p. 248.

MINERAL AND [Book I.

MINERAL AND THERMAL SPRINGS. `

Almost all springs, even those which we consider the
purest, are impregnated with some foreign ingredients
which, being in a state of chemical solution, are 80
intimately blended with the water, as not to affect its
clearness, while they render it, in general, more agree-
able to our taste, and more nutritious than simple
rain-water. But the springs called mineral contain a®
unusual abundance of earthy matter in solution, and
the substances with which they are impregnated cor
respond remarkably with those evolved in a gaseous
form by volcanos. Many of these springs are thermal,
and they rise up through all kinds of rock; as, for
example, through granite, gneiss, limestone, or lava
but are most frequent in volcanic regions, or wheré
violent earthquakes have occurred at eras compara-
tively modern.

The water given out by hot springs is generally
more voluminous and less variable in quantity at dif
ferent seasons than that proceeding from any others
In many volcanic regions, jets of steam, called by the
Italians «< stufas,” issue from fissures, at a temperature
high above the boiling point, as in the neighbourhood
of Naples, and in the Lipari Isles, and are disengaged
unceasingly for ages. Now, if such columns of steam
which are often mixed with other gases, should be
condensed before reaching the surface, by coming
contact with strata filled with cold water, they may
give rise to thermal and mineral springs of every
degree of temperature. It is, indeed, by this means
only, and not by hydrostatic pressure, that we cab
account for the rise of such bodies of water from great

Chin ` THERMAL SPRINGS. 309

depths ; nor can we hesitate to admit the adequacy of
the cause, if we suppose the expansion of the same
elastic fluids to be sufficient to raise columns of lava
to the lofty summits of volcanic mountains. Several
gases, the carbonic acid in particular, are disengaged
in a free state from the soil in many districts, especi-
ally in the regions of active or extinct volcanos ; and
the same are found more or less intimately combined
with the waters of all mineral springs, both cold and
thermal. Dr. Daubeny and other writers have re-
marked, not only that these springs are most abundant
in volcanic regions, but that when remote from them,
their site usually coincides with the position of some
great derangement in the strata; a fault, for example,
or great fissure, indicating that a channel of commu-
hication has been opened with the interior of the earth
at some former period of local convulsion.

The small area of volcanic regions may appear, at
first view, an objection to this theory, but not so when
We include earthquakes among the effects of igneous
agency. A large proportion of the land hitherto ex-
plored by geologists can be shown to have been rent
or shaken by subterranean movements since the oldest
tertiary strata were formed. It will also be seen, in
the sequel, that new springs have burst out, and others
have had the volume of their waters augmented, and
their temperature suddenly raised after earthquakes ;
so that the description of these springs might almost
With equal propriety have been given under the head
of “igneous causes,” as they are agents of a mixed
hature, being at once igneous and aqueous.

But how, it will be asked, can the regions of volcanic
heat send forth such inexhaustible supplies of water ?
The difficulty of solving this problem would, in truth,

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310 MINERAL SPRINGS. [Book Il.

be insurmountable, if we believed that all the atmo-
spheric waters found their way into the basin of the
ocean; but in boring near the shore, we often meet
with streams of fresh water at the depth of several
hundred feet below the sea level; and these probably
descend, in many cases, far beneath the bottom of the
sea, when not artificially intercepted in their course
Yet, how much greater may be the quantity of salt
water which sinks beneath the floor of the ocea
through the porous strata of which it is often com-
posed, or through fissures rent in it by earthquakes!
After penetrating to a considerable depth, this water
may encounter a heat of sufficient intensity to convert
it into vapour, even under the high pressure to which
it would then be subjected. This heat would pro-
bably be nearest the surface in volcanic countries, ané
farthest from it in those districts which have bee?
longest free from eruptions or earthquakes; but 1?
pursue this inquiry farther would lead us to antici
pate many topics belonging to another division of out
subject.

It would follow from the views above explained,
that there must be a two-fold circulation of terrestrial
waters; one caused by solar heat, and the other by
heat generated in the interior of our planet. We
know that the land would be unfit for vegetation, if
deprived of the waters raised into the atmosphere by
the sun; but it is also true that mineral springs are
powerful instruments in rendering the surface sub-
servient to the support of animal and vegetable life.
Their heat is said to promote the development of the
aquatic tribes in many parts of the ocean, and the
substances which they carry up from the bowels of the

Ch. IIL] CALCAREOUS SPRINGS. 311
farth to the habitable surface, are of a nature and ina
form which adapts them peculiarly for the nutrition of
animals and plants.

As these springs derive their chief importance to
the geologist from the quantity and quality of the
farthy materials which, like volcanos, they convey
ftom below upwards, they may properly be considered
u reference to the ingredients which they hold in
Solution. These consist of a great variety of sub-
‘tances; but the most predominant are, carbonate of
lime, carbonic and sulphuric acids, iron, silica, mag-
desia, alumine, and salt, besides petroleum, or liquid

itumen, and its various modifications, such as mineral
Pitch, naptha, and asphaltum.

Calcareous springs. — Our first attention is naturally
directed to springs which are highly charged with cal-
“areous matter; for these produce a variety of phe-
omena of much interest in geology. It is known that
‘ain-water has the property of dissolving the calcareous
rocks over which it flows, and thus, in the smallest
Ponds and rivulets, matter is often supplied for the
farthy secretions of testacea, and for the growth of
Certain plants on which they feed. But many springs
hold so much carbonic acid in solution, that they are
fnabled to dissolve a much larger quantity of cal-
Careous matter than rain-water; and when the acid is
dissipated in the atmosphere, the mineral ingredients
are thrown down, in the form of tufa or travertin.*

Auvergne— Calcareous springs, although most abun-
dant in limestone districts, are by no means confined

* The more loose and porous rock, usually containing incrusted

Plants and other substances, is called tufa; the more compact,
travertin. See Glossary, ‘ Tufa,’ ‘ Travertin, end of Vol. I.

312 CALCAREOUS SPRINGS. [Book Il.

to them, but flow out indiscriminately from all rock
formations. In Central France, a district where the
primary rocks are unusually destitute of limestone
springs copiously charged with carbonate of lime rise
up through the granite and gneiss. Some of these are
thermal, and probably derive their origin from the
deep source of volcanic heat, once so active in that
region. One of these springs, at the northern base of
the hill upon which Clermont is built, issues from vol-
canic peperino, which rests on granite. It has formed,
by its incrustations, an elevated mound of travertin, oF
white concretionary limestone, 240 feet in length, and,
at its termination, sixteen feet high and twelve wide:
Another incrusting spring in the same department
situated at Chaluzet, near Pont Gibaud, rises in 2
gneiss country, at the foot of a regular volcanic con®
at least twenty miles from any calcareous rock. Some
masses of tufaceous deposit, produced by this spring
have an oolitic texture.

Valley of the Elsa.—If we pass from the volcani¢
district of France to that which skirts the Apennines
in the Italian peninsula, we meet with innumerable
springs which have precipitated so much calcareous
matter, that the whole ground in some parts of Tus-
cany is coated over with travertin, and sounds hollow
beneath the foot.

In other places in the same country, compact rocks
are seen descending the slanting sides of hills, very
much in the manner of lava currents, except that they
are of a white colour, and terminate abruptly whe?
they reach the course of a river. These consist of
the calcareous precipitate of springs, some of them
still flowing, while others have disappeared or changed
their position. Such masses are frequent on the slope

Ch. TIL] CALCAREOUS SPRINGS. 313

of the hills which bound the valley of the Elsa, one of
the tributaries of the Arno, which flows near Colle;
through a valley several hundred feet deep, shaped.
out of a lacustrine formation, containing fossil ‘shells of
existing species. The travertin is unconformable. to
the lacustrine beds, and its inclination accords with
the slope of the sides of the valley.

One of the finest examples which I saw, was at the
Molino delle Caldane, near Colle.

The Sena, and several other small rivulets which
feed the Elsa, have the property of lapidifying wood
and herbs ; and, in the bed of the Elsa itself, aquatic
Plants, such as Charz, which absorb large quantities
of carbonate of lime, are very abundant. Carbonic acid
is also seen in the same valley, bubbling up from many
Springs, where no precipitate of tufa is observable.
Targioni, who in his travels has. mentioned a great
number of mineral waters in Tuscany, found no dif-
ference between the deposits of cold and thermal
Springs. They issue sometimes from the older Apen-
Nine limestone, shale, and sandstone, while, in other
Places, they flow from more modern deposits; but
€ven in the latter case, their source may probably be
in or below the older series of strata.

Baths of San Vignone.—Those persons who have
Merely seen the action of petrifying waters in our own
Country, will not easily form an adequate. conception
of the scale on which the same process is exhibited
in those regions which lie nearer to the active centres
of volcanic disturbance. One of the most striking
€xamples of the rapid precipitation of carbonate of
lime from thermal waters occurs in the hill of San
Vignone in Tuscany, at a short distance from Radi-
Cofani, and only a few hundred yards from the high

VOL. I. P

SRLS LE LE AN ea i EA

314 TRAVERTIN [Book IL.

road between Sienna and Rome. The spring issues
from near the summit of a rocky hill, about 100 feet in
height. The top of the hill is flat, and stretches in 4
gently inclined platform to the foot of Mount Amiata,
a lofty eminence, which consists in great part of vol-
canic products. The fundamental rock, from which
the spring issues, is a black slate, with serpentine
(bb. Fig. 11.), belonging to the older Apennine form-
ation. The water is hot, has a strong taste,~ and,
Baths of San Vignone.

Orcia
River.

Section of Travertin, San Vignone.

when not in very small quantity, is of a bright greer
colour. So rapid is the deposition near the source,
that in the bottom of a conduit-pipe for carrying off the
water to the baths, and which is inclined at an angle
of 30°, half a foot of solid travertin is formed every
year. A more compact rock is produced where the
water flows slowly, and the precipitation in winter
when there is least evaporation, is said to be more
solid, but less in quantity by one fourth, than i}
summer. The rock is generally white; some parts of
it are compact, and ring to the hammer ; others are
cellular, and with such cavities as are seen in the
carious part of bone or the siliceous millstone of the —
Paris basin. A portion of it also below the village of

Ch. 111] OF SAN VIGNONE. 315

San Vignone consists of incrustations of long vegetable
tubes, and may be called tufa. Sometimes the tra-
vertin assumes precisely the botryoidal and mammillary
forms, common to similar deposits in Auvergne, of a
much older date, hereafter to be mentioned ; and, like
them, it often scales off in thin, slightly undulating layers.
A large mass of travertin (e, Fig. 11.) descends the
hill from the point where the spring issues, and reaches
to the distance of about half a mile east of San Vig-
none. ‘The beds take the slope of the hill at about an
angle of 6°, and the planes of stratification are per-
fectly parallel. One stratum, composed of many
_ layers, is of a compact nature, and fifteen feet thick :
it serves as an excellent building stone, and a mass of
fifteen feet in length was, in 1828, cut out for the new
bridge over the Orcia. Another branch of it (a, Fig. 11.)
descends to the west, for 250 feet in length, of varying
thickness, but sometimes 200 feet deep : it is then cut
off by the small river Orcia, precisely as some glaciers
in Switzerland descend into a valley till their progress
is suddenly arrested by a transverse stream of water.
The abrupt termination of the mass of rock at the
river, when its thickness is undiminished, clearly shows
that it would proceed much farther if not arrested by
the stream, over which it impends slightly. But it
cannot encroach upon the channel of the Orcia, being
constantly undermined, so that its solid fragments are
seen strewed amongst the alluvial gravel. However
enormous, therefore, the mass of solid rock may appear
which has been given out by this single spring, we
may feel assured that it is insignificant in volume when
compared to that which has been carried to the sea
since the time when it began to flow. What may
have been the length of that period of time, we have
Pp 2

316. TRAVERTIN OF SAN FILIPPO. [Book IT.

no data for conjecturing. In quarrying the travertin,
Roman tiles have been sometimes found at the depth
of five or six feet.

Baths of San Filippo.—On another hill, not many
miles from that last mentioned, and also connected
with Mount Amiata, the summit of which is about
three miles distant, are the celebrated baths of San
Filippo. The subjacent rocks consist of alternations
of black slate, limestone, and serpentine, of highly
inclined strata, belonging to the Apennine formation,
and, as at San Vignone, near the boundary of a tertiary
basin of marine origin, consisting chiefly of blue argil-
laceous marl. There are three warm springs here,
containing carbonate and sulphate of lime, and sul-
phate of magnesia. The water which supplies the
baths falls into a pond, where it has been known to
deposit a solid mass thirty feet thick, in about twenty
years.* A manufactory of medallions in basso-relievo
is carried on at these baths. The water is conducted
by canals into several pits, in which it deposits tra-
vertin and crystals of sulphate of lime. After being
thus freed from its grosser parts, it is conveyed by a
tube to the summit of a small chamber, and made to
fall through a space of ten or twelve feet. The cur-
rent is broken in its descent by numerous crossed
sticks, by which the spray is dispersed around upon
certain moulds, which are rubbed lightly over with a
solution of soap, and a deposition of solid matter like
marble is the result, yielding a beautiful cast of the
figures formed in the mould.+ The geologist may
derive from these experiments considerable light, in

* Dr. Grosse on the Baths of San Filippo. Ed. Phil. Journ-
yol: ii. p. 292. i to Id. p297:

Q

Ch, 111] SPHEROIDAL TRAVERTIN. 317

regard to the high inclination at which some semi-
crystalline precipitations can be formed ; for some of
the moulds are disposed almost perpendicularly, yet
the deposition is nearly equal in all parts.

A hard stratum of stone, about a foot in thickness,
is obtained from the waters of San Filippo in four
months ; and, as the springs are powerful, and almost
uniform in the quantity given out, we are at no loss to
comprehend the magnitude of the mass which de-
scends the hill, which is a mile and a quarter in length
and the third of a mile in breadth, in some places
attaining a thickness of 250 feet at least. To what
length it might have reached it is impossible to con-
jecture, as it is cut off, like the travertin of San
Vignone, by a small stream, where it terminates
abruptly. The remainder of the matter held in-solu-
tion is carried on probably to the sea.

Spheroidal structure in travertin. — But what renders
this recent limestone of peculiar interest to the geo-
logist, is the spheroidal form which it assumes, analo-
gous to that of the cascade of Tivoli, afterwards to be
described. The lamination of some of the concentric
Masses is so minute that sixty may be counted in the

thickness of an inch, yet, notwithstanding these marks
of gradual and successive deposition, sections are
Sometimes exhibited of what might seem to be perfect
Spheres. This tendency toa mammillary and globular
Structure arises from the facility with which the cal-
Careous matter is precipitated in nearly equal quan-
tities on all sides of any fragment of shell or wood, or
any inequality of the surface over which the mineral
Water flows, the form of the nucleus being readily
transmitted through any number of successive enve-
lopes.. But these masses can never be perfect spheres,
Pd

ra

318 SPHEROIDAL TRAVERTIN. [Book I1.

although they often appear such when a transverse
section is made in any line not in the direction of the
point of attachment. There are, indeed, occasionally
seen small oolitic and pisolitic grains, of which the
form is globular ; for the nucleus, having been for a time
in motion in the water, has received fresh accessions of
matter on all sides.

In the same manner I have seen, on the vertical
walls of large steam boilers, the heads of nails or
rivets covered by a series of enveloping crusts of
calcareous matter, usually sulphate of lime ; so that a
concretionary nodule is formed, preserving a nearly
globular shape, when increased to a mass several
inches in diameter. In these, as in many travertins,
there is often a combination of the concentric and

radiated structure, and the last-mentioned character
is one of those in which the English magnesian lime-

stone agrees with the Italian travertins.

Another point of resemblance between these rocks;
in other respects so dissimilar, is the interference of
one sphere with another, and the occasional occurrence
of cavities and vacuities, constituting what has been
called a honeycombed structure, and also the frequent
interposition of loose incoherent matter, between dif-
ferent solid spheroidal concretions. Yet, notwith-
standing such points of analogy, Professor Sedgwick
observes, that there are proofs of the concretionary
arrangement inthe magnesian limestone having taken
place subsequently to original deposition, for in this
case the spheroidal forms are often quite independent
of the direction of the laminz.*

* Geol. Trans. 2nd series, vol. iii. p. 37. I have lately see”
some specimens of spheroidal magnesian limestone, collected by
Professor Sedgwick, where the calcareous lamin are intersected

Ch, ILJ CALCAREOUS SPRINGS. 319

Bulicamiof Viterbo—I must not attempt to describe
all the places in Italy where the constant formation of
limestone may be seen, as on the Silaro, near Pæstum,
on the Velino at Terni, and in the vicinity of Viterbo.
About a mile and a halfnorth of the latter town, in the
midst of a sterile plain of volcanic sand and ashes, and
near the hot baths called the Bulicami, a monticule is
seen, about twenty feet high and five hundred yards in
circumference, entirely composed of concretionary
travertin. This rock has been largely quarried for
lime, and much of it appears to have been removed.
The laminz are very thin, and their minute undulations
so arranged, that the whole mass has at once a con-
centric and radiated structure. The beds dip at an
angle of 40° or more from the centre of the monticule
outwards. The whole mass has evidently been formed
gradually, like the conical mounds of the geysers in

Iceland, by a small jet or fountain of calcareous water,
which overflowed from the summit of the monticule.
A spring of hot water still issues in the neighbourhood,
which is conveyed to an open tank used as a bath, the
bottom and sides of which, as well as the open conduit
which conveys the water, are encrusted with travertin.

at a high angle by the boundary line of the globule of which they
form a part. In a former edition I stated, that on visiting
Sunderland immediately after examining the travertins of Au-
Vergne and Sicily (the former of lacustrine, the latter of submarine
origin), I recognized a striking degree of identity in the pre-
Vailing concretionary forms assumed by our magnesian limestone
and those of the travertins with the appearance of which my ey
was then familiar. I am still convinced that much light would be
thrown on the mode of formation of both these rocks by a com-
Parison of the points in which they mutually agree with or differ
from each other.

P4

390 CALCAREOUS PRECIPITATES [Book II.

Campagna di Roma.— The country around Rome;
like many parts of the Tuscan States already referred
to, has been at some former period the site of numerous
volcanic eruptions ; and the springs are still copiously
impregnated with lime, carbonic acid, and sulphuretted
hydrogen. A hot spring has lately been discovered
near Civita Vecchia, by Signor Riccioli, which deposits
alternate beds of a yellowish travertin, and a white
granular rock, not distinguishable, in hand specimens,
either in grain, colour, or composition, from statuary
marble. There is a passage between this and ordinary
travertin. The mass accumulated near the spring is in
some places about six feet thick. .

Lake of the Solfatara.—In the Campagna, between
Rome and Tivoli, is the lake of the Solfatara, called
also Lago di Zolfo (lacus albula), into which flows con-
tinually a stream of tepid water, from a smaller lake
situated a few yards above it. The water is a saturated
solution of carbonic acid gas, which escapes from it 12
such quantities in some parts of its surface, that it has
the appearance of being actually in ebullition. «I have
found by experiment,” says Sir Humphry Davy, “that
the water taken from the most tranquil part of the
lake, even after being agitated and exposed to the ait;
contained in solution more than its own volume of car-
bonic acid gas, with a very small quantity of sulphu-
retted hydrogen. Its high temperature, which is pretty
constant at 80° of Fahr., and the quantity of carbonic
acid that it contains, render it peculiarly fitted to afford
nourishment to vegetable life. The banks of travertin
are every where covered with reeds, lichen, conferv®;
and various kinds of aquatic vegetables; and at the
_ same time that the process of vegetable life is going
on, the crystallizations of the calcareous matter, which

Ch, IIL] OF THE CAMPAGNA DI ROMA. 821
is every where deposited, in consequence of the escape
of carbonic acid, likewise proceed.—There is, I believe,
no place in the world where there is a more striking
example of the opposition or contrast of the laws of
animate and inanimate nature, of the forces of inorganic
chemical affinity, and those of the powers of life.” *

The same observer informs us, that he fixed a stick
in a mass of travertin covered by the water in the
month of May, and in April following he had some
difficulty in breaking, with a sharp pointed hammer,
the mass which adhered to the stick, and which was
several inches in thickness. The upper part was a
mixture of light tufa and the leaves of conferve : below
this was a darker and more solid travertin, containing
black and decomposed masses of confervee ; inthe in-
ferior part the travertin was more solid, and of a grey
colour, but with cavities probably produced by the
decomposition of vegetable matter. +

The stream which flows out of this lake fills a canal
about nine feet broad and four deep, and is conspicuous
in the landscape by a line of vapour which rises from
it. It deposits calcareous tufa in this channel, and the
Tiber probably receives from it, as well as from nu-
merous other streams, much carbonate of lime in solu-
tion, which may contribute to the rapid growth of its
delta. A large proportion of the most splendid edifices
of ancient and modern Rome are built of travertin,
derived from the quarries of Ponte Leucano, where
there has evidently been a lake at a remote period, on
the same plain as that already described. But the
consideration of these would carry us beyond the

* Consolations in Travel, pp. 123—125.
+ Id. p. 127.
s P 5

399 TRAVERTIN OF TIVOLI. [Book If

times of history, and I shall conclude with one more
example of the calcareous deposits of this neighbour-
hood, — those on the Anio.

Travertin of Tivoli.—The waters of the Anio
incrust the reeds which grow on its banks, and the
foam of the cataract of Tivoli forms beautiful pendant
Stalactites ; but, on the sides of the deep chasm into
which the cascade throws itself, there is seen an
extraordinary accumulation of horizontal beds of tufa
and travertin, from four to five hundred feet in
thickness. The section immediately under the temples
of Vesta and the Sibyl, displays, in a precipice about
four hundred feet high, some spheroids which are from
six to eight feet in diameter, each concentric layer being
about the eighth of an inch in thickness. The annexed
diagram exhibits about fourteen feet of this immense
mass, as seen in the path cut out of the rock in descend-
ing from the temple of Vesta to the Grotto di Nettuno:
I have not attempted to express in this drawing the
innumerable thin layers of which these magnificent
spheroids are composed, but the lines given mark
some of the natural divisions into which they are
separated by minute variations in the size or colour of
the laminæ. The undulations also are much smaller,
in proportion to the whole circumference, than in the
drawing. The beds a a are of hard travertin and soft
tufa ; below them is a pisolite (b), the globules being
of different sizes: underneath this appears a mass of
concretionary travertin (e c), some of the spheroids
being of the above-mentioned extraordinary size. In
some places (as at d) there is a mass of amorphous
limestone, or tufa, surrounded by concentric layers.
At the bottom is another bed of pisolite (b), in which
the small nodules are about the size and shape of

Ch. IIL] TRAVERTIN OF TIVOLI. 323

beans, and some of them of filberts, intermixed with
Some smaller oolitic grains. In the tufaceous strata,
Wood is seen converted into a light tufa.

The following seems the most probable explanation
Fig, 12.

Section of Spheroidal Concretionary Travertin under the Cascade of Tivoli.

of the origin of the rock in this singular position.
The Anio flows through a deep irregular fissure or
P 6

394: TRAVERTIN OF TIVOLI. ' [Book IL

gorge in the Apennine limestone, which may have
been caused by earthquakes. In this deep narrow
channel there existed many small lakes, three of which
have been destroyed since the time of history, by the
erosive action of the torrent, the last of them having
remained down to the sixth century of our era.

We may suppose a similar lake of great depth to
have existed at some remote period at Tivoli, and
that, into this, the waters, charged with carbonate of
lime, fell from a height inferior to that of the present
cascade. Having, in their passage through the upper
lakes, parted with their sand, pebbles, and coarse
sediment, they only introduced into this lower pool
drift-wood, leaves, and other buoyant substances. In
seasons when the water was low, a deposit of ordinary
tufa, or of travertin, formed along the bottom ; but at
other times, when the torrent was swollen, the pool
must have been greatly agitated, and every small
particle of carbonate of lime which was precipitated
must have been whirled round again and again in
various eddies, until it acquired many concentric coats,
so as to resemble oolitic grains. If the violence of the
motion be sufficient to cause the globule to be sus-
pended for a sufficient length of time, it would grow
to the size of a pea, or much larger. Small fragments
of vegetable stems being incrusted on the sides of the
stream, and then washed in, would form the nucleus
of oval globules, and others of irregular shapes would
be produced by the resting of fragments for a time on
the bottom of the basin, where, after acquiring an un-
equal thickness of travertin on one side, they would
again be setin motion. Sometimes globules, projecting
above the general level of a stratum, would attract, by
cheminal affinity, other matter in the act of precipi-

o Ch, TIL] ” CALCAREOUS TUFA. 325

tation, and thus growing on all sides, with the exception
of the point of contact, might at length form spheroids
nearly perfect and many feet in diameter. Masses
might increase above and below, so that a vertical
section might afterwards present the phenomenon so
common at Tivoli, where the nucleus of some of the
concentric circles has the appearance of having been
Suspended, without support, in the water, until it
became a spheroidal mass of great dimensions.

It is probable that the date of the greater portion
of this calcareous formation may be anterior to the
era of history, for we know that there was a great
cascade at Tivoli in very ancient times; but, in the
Upper part of the travertin, is shown the hollow left.
by a wheel, in which the outer circle and the spokes
have been decomposed, and the spaces which they
filled have been left void. It seems impossible to
explain the position of this mould, without supposing
that the wheel was imbedded before the lake was
drained.

Caleareous springs in the Caucasus. — Pallas, in his
journey along the Caucasus, a country now subject,
from time to time, to be rent and fissured by violent
earthquakes, enumerates a great many hot springs,
which have deposited monticules of travertin precisely
analogous in composition and structure to those of
the baths of San Filippo and other localities in Italy.
When speaking of the tophus-stone, as he terms these
limestones, he often observes that it is snow-white, a
description which is very applicable to the newer part
of the deposit at San Filippo, where it has not become
darkened by weathering. In many localities in the
regions between the Caspian and Black Seas, where
subterranean convulsions are frequent, travellers men-

396 GYPSEOUS SPRINGS. [Book II.

tion calc-sinter as an abundant product of hot springs:
Near the shores of the Lake Urmia (or Maragha),
for example, a marble which is much used in orna-
mental architecture is rapidly deposited by a thermal
spring.*

It is probable that the zoophytic and shelly lime-
stones, which constitute the coral reefs of the Indian
and Pacific Oceans, are supplied with carbonate of
lime and other mineral ingredients from submarine
springs, and that their heat, as well as their earthy
and gaseous contents, may promote the development
of corals, sponges, and testacea, just as vegetation 1s
quickened by similar causes in the lake of the Solfatar3
before described. But of these reefs and their pro-
bable origin I shall again have occasion to speak in
the third book.

_, Sulphureous and gypseous springs.— The quantity of
"| other mineral ingredients wherewith springs in general
lare impregnated, is insignifiant in comparison to lime,
„and this earth is most frequently combined with car-
bonic acid. But, as sulphuric acid and sulphuretted
hydrogen are very frequently supplied by spring’
gypsum may, perhaps, be deposited largely in certai?
. Seas and lakes. The gypseous precipitates, however
hitherto known on the land, appear to be confined to 4
very few springs. Those at Baden, near Vienna, which
feed the public bath, may be cited as examples. Somé
of these supply, singly, from 600 to 1000 cubic feet of
water per hour, and deposit a fine powder, composed
of a mixture of sulphate of lime, with sulphur and
muriate of lime.+

* Von Hoff, Geschichte, &c. vol. ii. p. 114.
ł C. Prevost, Essai sur la Constitution Physique du Bassin de
Vienne, p. 10.

Ch. 111.7 SILICEOUS SPRINGS. 597

Siliceous springs. —Azores.—In order that water
should hold a very large quantity of silica in solution,
it seems necessary that it should be raised to a high
temperature *; and as it may retain a greater heat
under the pressure of the sea than in the atmosphere,
Submarine springs may, perhaps, be more charged
With silex than any to which we have access. The
hot springs of the Valle das Furnas, in the Island of
St. Michael, rising through volcanic rocks, precipitate
Vast quantities of siliceous sinter, as it is usually
termed. Around the circular basin of the largest
spring, which is between twenty and thirty feet in
diameter, alternate layers are seen of a coarser variety
of sinter mixed with clay, including grass, ferns, and
reeds, in different states of petrifaction. Wherever
the water has flowed, sinter is found rising in some
places eight or ten inches above the ordinary level of
the stream. The herbage and leaves, more or less
incrusted with silex, are said to exhibit all the suc-
cessive steps of petrifaction, from the soft state toa
complete conversion into stone; but in some in-
stances, alumina, which is likewise deposited from the
hot waters, is the mineralizing material. Branches of
the same ferns which now flourish in the island are
found completely petrified, preserving the same ap-
pearance as when vegetating, except that they acquire
an ash-gray colour. Fragments of wood, and one en-
tire bed from three to five feet in depth, composed of
reeds now common in the island, have become com-
pletely mineralized.

The most abundant variety of siliceous sinter occurs
in layers from a quarter to half an inch in thickness,

* Daubeny:on Volcanos, p. 222.

328 GEYSERS OF ICELAND. [Book 11:

accumulated on each other often to the height of a
foot and upwards, and constituting parallel, and for
the most part horizontal, strata many yards in extent.
This sinter has often a beautiful semi-opalescent lustre.
One of the varieties differs from that of Iceland and
Ischia in the larger proportion of water it contains,
and in the absence of alumina and lime. A recent
breccia is also in the act of forming, composed of obsi-
dian, pumice, and scoriz, cemented by siliceous sinter.*

Geysers of Iceland.— But the hot springs in various
parts of Iceland, particularly the celebrated geysers
afford the most remarkable example of the deposition
of silex.t The circular reservoirs into which the -
geysers fall, are filled in the middle with a variety of
opal, and round the edges with sinter. The plants
incrusted with the latter substance have much the
same appearance as those incrusted with calcareous
tufa in our own country.

In some of the thermal waters of Iceland a vesiculat
rock is formed, containing portions of vegetables more
or less completely silicified; and amongst other pro-
ducts of springs in this island, is that admixture of
clay and silica, called tripoli.

By analysis of the water, Mr. Faraday has ascer-
tained that the solution of the silex is promoted by
the presence of the alkali, soda. He suggests that
the deposition of silica in an insoluble state takes
place partly because the water when cooled by ex-
posure to the air is unable to retain as much silica
as when it issues from the earth at a temperature
of 180° or 190° Fahr. ; and partly because the evapo-

* Dr. Webster on the Hot Springs of Furnas, Ed.. Phil
Journ., vol. vi. p. 306.
+ See a cut of the Icelandic geyser, Book II. chap. 19.

Ch, IIL] SILICEOUS SPRINGS. 329

tation of the water decomposes the compound of silica
and soda which previously existed. This last change
is probably hastened by the carbonic acid of the atmo-
sphere uniting with the soda. The alkali, when dis-
United from the silica, would readily be dissolved in and
removed by running water.*

Ischia.-It has been found, by recent analysis, that
several of the thermal waters of Ischia are impregnated
With a certain proportion of silica. Some of the hot
vapours of that island are above the temperature of
boiling water; and many fissures, near Monte Vico,
through which the hot steam passes, are coated with
a siliceous incrustation, first noticed by Dr. Thompson
under the name of fiorite.

Ava, &e.— It has been often stated that the Danube
has converted the external part of the piles of Trajan’s
bridge into silex; the Irawadi, in Ava, has been sup-
Posed, ever since the time of the Jesuit Padre Duchatz,
to have the same petrifying power, as also Lough
Neagh, in Ireland. Modern researches, however, in
the Burman empire, have thrown doubt upon the
lapidifying property of the Ava river; there is cer-
tainly no foundation for the story in regard to Lough
Neagh, and probably none in regard to the Danube.

Mineral waters, even when charged with a small

‘Proportion of silica, as those of Ischia, may supply
Certain species of corals and sponges with matter for
their siliceous secretions; but when in a volcanig
archipelago, or a region of submarine volcanos, there
are springs so saturated with silica as those of Iceland

* Barrow’s Iceland, p. 209.
+ Dr. Buckland, Geol. Trans., 2nd series, vol. ii. part iii.
P. 384,

330 FERRUGINOUS SPRINGS. [Book 11

or the Azores, we may expect layers and nodules of
silex and chert to be spread out far and wide over
the bed of the sea, and interstratified with shelly and
calcareous deposits, which may be forming there, 0f
with matter derived from wasting cliffs or volcanic
ejections.

Ferruginous springs. —The waters of almost al
springs contain some iron in solution; and it is a fact
familiar to all, that many of them are so copiously
impregnated with this metal, as to stain the rocks of
herbage through which they pass, and to bind together
sand and gravel into solid masses. We may naturally
then, conclude that this iron, which is constantly cov
veyed from the interior of the earth into lakes and seas
and which does not escape again from them into thé
atmosphere by evaporation, must act as a colouring
and cementing principle in the subaqueous deposits
now in progress. It will be afterwards seen that many
sandstones and other rocks in the sedimentary strata of
ancient lakes and seas are bound together or coloured
by iron, and this fact presents us with a striking point
of analogy between the state of things at very different
epochs. In those older formations we meet with great
abundance of carbonate and sulphuret of iron ; and it
chalybeate waters at present, this metal is most fre-
quently in the state of a carbonate, as in those of Tun
bridge, for example. Sulphuric acid, however, is ofte”
the solvent, which is in many cases derived from the
- decomposition of pyrites. :

Brine springs. — Cheshire.— So great is the quan-
tity of muriate of soda in some springs, that they yield
one fourth of their weight in salt. They are rarely;
however, so saturated, and generally contain, inter-
mixed with salt, carbonate and sulphate of lime, mag-

Ch, 11.) BRINE SPRINGS. 331

nesia, and other mineral ingredients. The brine springs
of Cheshire are the richest in our country; those of
Barton and Northwich being almost and those of
Droitwich fully saturated.* They are known to have
flowed for more than 1000 years, and the quantity of
salt which they have carried into the Severn and
Mersey must be enormous. These brine springs rise
Up through strata of sandstone and red marl, which
Contain large beds of rock salt. The origin of the
brine, therefore, may be derived in this and many
other instances from beds of fossil salt ; but as muriate
of soda is one of the products of volcanic emanations
and of springs in volcanic regions, the original source
of salt may be as deep seated as that of lava.

Dead Sea.— The waters of the Dead Sea contain
Scarcely any thing except muriatic salts, which lends
Countenance, observes Dr. Daubeny, to the volcanic
origin of the surrounding country, these salts being
frequent products of volcanic eruptions. Many springs
m Sicily contain muriate of soda, and the “ fiume
salso,” in particular, is impregnated with so large a
quantity, that cattle refuse to drink of it.

Auvergne.— A hot spring, rising through granite, at
Saint Nectaire, in Auvergne, may be mentioned as one
of many, containing a large proportion of muriate of
Soda, together with magnesia and other ingredients.

Carbonated springs. — Auvergne. — Carbonic acid
gas is very plentifully disengaged from springs in
almost all countries, but particularly near active or
extinct volcanos. ‘This elastic fluid has the property
of decomposing many of the hardest rocks with which
it comes in contact, particularly that numerous class

* L. Homer, Geol. Trans. vol. ii. p. 94.
+ Annales de l’ Auvergne, tome i. p- 234.

332 CARBONATED SPRINGS, ` [Book I

in whose composition felspar is an ingredient. It
renders the oxide of iron soluble in water, and con-
tributes, as was before stated, to the solution of cal
careous matter. In volcanic districts these gaseous
emanations are not confined to springs, but rise up 1”
the state of pure gas from the soil in various places
The Grotto del Cane, near Naples, affords an examples
and prodigious quantities are now annually disengaged
from every part of the Limagne d’ Auvergne, where if
appears to have been developed in equal quantity from
time immemorial. As the acid is invisible, it is not
observed, except an excavation be made, wherein if
immediately accumulates, so that it will extinguish 4
candle. There are some springs in this district, where
the water is seen bubbling and boiling up with much
Noise, in consequence of the abundant disengagement
of this gas. The whole vegetation is affected, and
many trees, such as the walnut, flourish more luxu-
riantly than they would otherwise do in the same soil
and climate — the leaves probably absorbing carboni¢
acid. This gas is found in springs rising through the
granite near Clermont, as well as in the tertiary lime-
Stones of the Limagne.* In the environs of Pont-
Gibaud, not far from Clermont, a rock belonging t0
the gneiss formation, in which lead-mines are worked,
has been found to be quite saturated with carbonic acid.
gas, which is constantly disengaged. The carbonates
of iron, lime, and manganese are so dissolved, that the
rock is rendered soft, and the quartz alone remains
unattacked.+ Not far off is the small volcanic cone of
Chaluzet, which once broke up through the gneiss, and
sent forth a lava-stream.

* Le Coq, Annales de l Auvergne, tomei. p. 217. May, 1828.
ft Ann. Scient, de l Auvergne, tome ii. J une, 1829.

Ch. Tir] DISINTEGRATION OF GRANITE. 333

Disintegration of granite.— The disintegration of
Stanite is a striking feature of large districts in Au-
vergne, especially in the neighbourhood of Clermont.

is decay was called by Dolomieu, “la maladie du
Stanite ;” and the rock may with propriety be said to

ave the rot, for it crumbles to pieces in the hand.
he phenomenon may, without doubt, be ascribed to
ihe continual disengagement of carbonic acid gas from
‘umerous fissures.

In the plains of the Po, between Verona and Parma,
“Specially at Villa Franca, south of Mantua, I observed
Steat beds of alluvium, consisting chiefly of primary
Pebbles, percolated by spring water, charged with car-
nate of lime and carbonic acid in great abundance.

hey are for the most part incrusted with calc-sinter :
“nd the rounded blocks of gneiss, which have all the
‘utward appearance of solidity, have been so disin-

tegrated by the carbonic acid as readily to fall to
Pieces,

The subtraction of many of the elements of rocks
YY the solvent power of carbonic acid, ascending both
Na gaseous state and mixed with spring-water in the
“tevices of rocks, must be one of the most powerful
Sources of those internal changes and re-arrangements
0f particles so often observed in strata of every age.

he calcareous matter, for example, of shells is often
“ntirely removed and replaced by carbonate of iron,
Pyrites, silex, or some other ingredient, such as mine-
tal waters usually contain in solution. It rarely hap-
Pens, except in limestone rocks, that the carbonic acid
“an dissolve all the constituent parts of the mass; and
or this reason, probably, calcareous rocks are almost

e only ones in which great caverns and long winding
Passages are found.

334: PETROLEUM SPRINGS. — [Book If.

Petroleum springs. — Springs impregnated with pe-
troleum, and the various minerals allied to it, as bitu-
men, naphtha, asphaltum, and pitch, are very numer-
ous, and are, in many cases, undoubtedly connected
with subterranean fires, which raise or sublime the
more subtle parts of the bituminous matters contained
in rocks. Many springs in the territory of Modena
and Parma, in Italy, produce petroleum in abundance
but the most powerful, perhaps, yet known, are thos
on the Irawadi, in the Burman empire. In one locality
there are said to be 520 wells, which yield annually
400,000 hogsheads of petroleum.*

Fluid bitumen is seen to ooze from the bottom of
the sea, on both sides of the island of Trinidad, and
to rise up to the surface of the water. Near Cape La
Braye there is a vortex which, in stormy weather,
_ according to Captain Mallet, gushes out, raising the
water five or six feet, and covers the surface for a con-
siderable space with petroleum, or tar; and the same
author quotes Gumilla, as stating in his “ Description
of the Orinoco,” that about seventy years ago, a spot
of land on the western coast of Trinidad, near half
way between the capital and an Indian village, sank
suddenly, and was immediately replaced by a small
lake of pitch, to the great terror of the inhabitants.t

Pitch lake of Trinidad. — It is probable that the
great pitch lake of Trinidad owes its origin to #
similar cause; and Dr. Nugent has justly remarked,
that in that district all the circumstances are nO
combined from which deposits of pitch may have
originated. The Orinoco has for ages been rolling

* Symes, Embassy to Ava, vol. ii, — Geol. Trans., second
series, vol. ii. part iii. p. 388.
+ Dr. Nugent, Geol. Trans, vol.i. p. 69.

Ch. 111.) PETROLEUM SPRINGS. 335

down great quantities of woody and vegetable bodies
into the surrounding sea, where, by the influence of
currents and eddies, they may be arrested and accu-
mulated in particular places. The frequent occurrence
of earthquakes and other indications of volcanic action
in those parts lend countenance to the opinion, that
these vegetable substances may have undergone, by
the agency of subterranean fire, those transformations
and chemical changes which produce petroleum, and
this may, by the same causes, be forced up to the
surface, where, by exposure to the air, it becomes
inspissated, and forms the different varieties of pure
and earthy pitch, or asphaltum, so abundant in the
island.*

The bituminous shales, so common in geological
formations of different ages, as also many stratified
deposits of bitumen and pitch, seem clearly to attest
that, at former periods, springs, in various parts of the
world, were as commonly impregnated as now with
bituminous matter, carried down, probably, by rivers
into lakes and seas. It will, indeed, be easy to show,
that a large portion of the finer particles and the
more crystalline substances, found in sedimentary rocks
of different ages, are composed of the same elements
as are now held in solution by springs, while the
coarser materials bear an equally strong resemblance
to the alluvial matter in the beds of existing torrents
and rivers.

* Dr. Nugent, Geol. Trans. vol. i. p. 67.

CHAPTER IV.
REPRODUCTIVE EFFECTS OF RUNNING WATER.

Reproductive effects of running water — Division of Deltas into
lacustrine, mediterranean, and oceanic — Lake deltas— Growth
of the delta of the Upper Rhone in the Lake of Geneva—
Chronological computations of the age of deltas — Recent
deposits in Lake Superior (p. 342.) — Deltas of inland seas —
Rapid shallowing of the Baltic — Marine delta of the Rhone
(p. 345.) — Various proofs of its increase — Stony nature of its
deposits — Delta of the Po, Adige, Isonzo, and other rivers
entering the Adriatic— Rapid conversion of that gulf into land
— Mineral characters of the new deposits — Delta of the Nile
(p. 353.) — Its increase since the time of Homer — Its growth

why checked at present.

Havine considered the destroying and transporting
agency of running water, we have now to examine the
reproductive effects of the same cause. The aggre-
gate amount of deposits accumulated in a given time
at the mouths of rivers, where they enter a lake or
sea, affords clearer data for estimating the energy of
the excavating power of running water on the land,
than the separate study of the operations of the same
cause in the countless ramifications into which every
great system of valleys is divided. I shall therefore
proceed to select some of the leading facts at present
ascertained respecting the growth of deltas, and shall
then offer some general observations on the quantity
of sediment transported by rivers, and the manner of
its distribution beneath the waters of lakes and seas-

Ch, 1V.] DELTA OF THE RHONE. 337

Division of deltas into lacustrine, mediterranean, and
oceanic. — Deltas. may be divided into, first, those
which are formed in lakes; secondly, those in inland
seas ; and thirdly, those on the borders of the ocean.
The most characteristic distinction between the lacus-
trine and marine deltas consists in the nature of the
organic remains which become imbedded in their
deposits ; for, in the case of a lake, it is obvious that
these must consist exclusively of such genera of
animals as inhabit the land or the waters of a river or
lake; whereas, in the other case, there will be an ad-
mixture and most frequently a predominance of animals
which inhabit salt water. In regard, however, to the
distribution of inorganic matter, the deposits of lakes

‘and inland seas are formed under very analogous cir-
cumstances, and may be distinguished from those on
the shores of the great ocean, where the tides co-

operating with currents give rise to another class of
phenomena. In lakes and inland seas, even of the
largest dimensions, the tides are almost insensible, but
the currents, as will afterwards appear, sometimes run
with considerable velocity.

DELTAS IN LAKES.

Lake of Geneva.— It is natural to begin our examin-
ation with an inquiry into the new deposits in lakes,
as they exemplify the first reproductive operations in
which rivers are engaged when they convey the de-
tritus of rocks and the ingredients of mineral springs
from mountainous regions. The accession of new land
at the mouth of the Rhone, at the upper end of the
Lake of Geneva, or the Leman Lake, presents us with
an example of a considerable thickness of strata which

VOL. I. Q

338 DELTA OF THE RHONE [Book II.

have accumulated since the historical era. This sheet
of water is about thirty-seven miles long, and its breadth
is from two to eight miles. The shape of the bottom
is very irregular, the depth having been found, by late
measurements, to vary from 20to 160 fathoms.* The
Rhone, where it enters at the upper end, is turbid and
discoloured ; but its waters, where it issues at the town
of Geneva, are beautifully clear and transparent. AD
ancient town, called Port Vallais, (Portus Valesize of
the Romans,) once situated at the water’s edge, at the
upper end, is now more than a mile and a half inland
— this intervening alluvial tract having been acquired
in about eight centuries. The remainder of the delta
consists of a flat alluvial plain, about five or six miles
in length, composed of sand and mud, a little raised
above the level of the river, and full of marshes.

Mr. De la Beche found, after numerous soundings
in all parts of the lake, that there was a pretty uniform
depth of from 120 to 160 fathoms throughout the cen-
tral region, and, on approaching the delta, the shal-
lowing of the bottom began to be very sensible at a
distance of about a mile and three quarters from the
mouth of the Rhone ; for a line drawn from St. Gin-
goulph to Vevey, gives a mean depth of somewhat less
than six hundred feet, and from that part to the Rhone,
the fluviatile mud is always found along the bottom. t
We may state, therefore, that the new strata annually
produced are thrown down upon a slope about two
miles in length: so that, notwithstanding the great
depth of the lake, the new deposits are not inclined at
a high angle ; the dip of the beds, indeed, is so slight,

* De la Beche, Ed. Phil. Journ. vol. ii. p. 107. Jan. 1820.
+ Dela Beche, MS,

Ch. IV.] IN THE LAKE OF GENEVA. 339

that they would be termed, in ordinary geological
language, horizontal.

The strata probably consist of alternations of finer
and coarser particles; for, during the hotter months
from April to August, when the snows melt, the volume
and velocity of the river are greatest, and large quan-
tities of sand, mud, vegetable matter, and drift-wood
are introduced; but, during the rest of the year, the
influx is comparatively feeble, so much so, that the
whole lake, according to Saussure, stands six feet
lower. If, then, we could obtain a section of the ac-
cumulation formed in the last eight centuries, we
should see a great series of strata, probably from 600
to 900 feet thick, (the supposed original depth of the
head of the lake,) and nearly two miles in length, in.
clined at a very slight angle. In the mean time, a
great number of smaller deltas are growing around the
borders of the lake, at the mouths of rapid torrents,
which pour in large masses of sand and pebbles. The
body of water in these torrents is too small to enable
them to spread out the transported matter over so ex-
tensive an area as the Rhone does. Thus, for example,
there is a depth of eighty fathoms within half a mile
of the shore, immediately opposite the great torrent
which enters east of Ripaille, so that the dip of the
strata in that minor delta must be about four times as
great as those deposited by the main river at the upper _
extremity of the lake.*

Chronological computations of the age of deltas. — The
capacity of this basin being now ascertained, it would
be an interesting subject of inquiry, to determine in
what number of years the Leman Lake will be con-

* De la Beche, MS.
Q 2

340 CHRONOLOGICAL COMPUTATIONS [Book II.

verted into dry land. It would not be very difficult to
obtain the elements for such a calculation, so as to
approximate at least to the quantity of time required
for the accomplishment of the result. The number of
cubic feet of water annually discharged by the river
into the lake being estimated, experiments might be
made in the winter and summer months, to determine
the proportion of matter held in suspension or in che-
mical solution by the Rhone. It would be also neces-
sary to allow for the heavier matter drifted along at the
bottom, which might be estimated on hydrostatical
principles, when the average size of the gravel and the
volume and velocity of the stream at different seasons
were known. Supposing all these observations to have
been made, it would be more easy to calculate the fu-
ture than the former progress of the delta, because it
would be a laborious task to ascertain, with any de-
gree of precision, the original depth and extent of that
part of the lake which is already filled up. Even if this
information were actually obtained by borings, it would
only enable us to approximate within a certain number
of centuries to the time when the Rhone began to form
its present delta; but,this would not give us the date
of the origin of the Leman Lake in its present form,
because the river may have flowed into it for thousands
of years, without importing any sediment whatever-
Such would have been the case, if the waters had first
passed through a chain of upper lakes; and that this
was actually the fact, is indicated by the course of the
Rhone between Martigny and the Lake of Geneva, and,
still more decidedly, by the channels of many of its
principal feeders.

If we ascend, for example, the valley through which
the Dranse flows, we find that it consists of a succession

Ch. IV.] OF THE AGE OF DELTAS. ~ 341

of basins, one above the other, in each of which there
is a wide expanse of flat alluvial lands, separated from
the next basin by a rocky gorge, once evidently the
barrier of a lake. The river has filled these lakes, one
after the other, and has partially cut through the bar-
riers, which it is still gradually eroding to a greater
depth. The examination of almost all valleys in moun-
tainous districts affords similar proofs of the obliter-
ation of a series of lakes, by the filling up of hollows
and the cutting through of rocky barriers — a process
by which running water ever labours to produce a
more uniform declivity. Before, therefore, we can
pretend even to hazard a conjecture as to the era at
which any particular delta commenced, we must be
thoroughly acquainted with the geographical features
and geological history of the whole system of higher
valleys which communicate with the main stream, and
all the changes which they have undergone since the
last series of convulsions which agitated and altered
the face of the country.

The probability, therefore, of error in our chrono-
logical computations where we omit to pay due atten-
tion to these circumstances, increases in proportion to
the time that may have elapsed since the last disturb-
ance of the country by subterranean movements, and
in proportion to the extent of the hydrographical basin
on which we may happen to speculate. The Alpine
rivers of Vallais are prevented at present from contri-
buting their sedimentary contingent to the lower delta
of the Rhone in the Mediterranean, because they are
intercepted by the Leman Lake ; but when this is filled,
they will transport as much, or nearly as much, matter
to the sea, as they now pour into that lake. They will
then flow through a long, flat, alluvial plain, between

Q 3

8349 DELTAS OF LAKE SUPERIOR. [Book II.

Villeneuve and Geneva, from two to eight miles in
breadth, which will present no superficial marks of the
existence of a thickness of more than one thousand
feet of recent sediment below. Many hundred alluvial
tracts of equal, and some of much greater area, may
be seen if we follow up the Rhone from its termination
in the Mediterranean, or explore the valleys of many
of its principal tributaries.

What, then, shall we think of the presumption of De
Luc, Kirwan, and their followers, who confidently de-
duced from the phenomena of modern deltas the recent
origin of the present form of our continents, without
pretending to have collected any one of the numerous
data by which so complicated a problem can be solved?
Had they, after making all the necessary investigations,
succeeded in proving, as they desired, that the lower
delta of the Rhone, and the new deposits at the
mouths of several other rivers, whether in lakes or seas,
had required about four thousand years to attain their
present dimensions, the conclusion would have been
fatal to the chronological theories which they were
anxious to confirm.

Lake Superior.— Lake Superior is the largest body
of fresh water in the world, being about 1500 geogra-
phical miles in circumference when we follow the
sinuosities of its coasts, and its length, on a curved
line drawn through its centre, being about 360, and
its extreme breadth 140 geographical miles. Its ave-
rage depth varies from 80 to 150 fathoms ; but, ac-
cording to Captain Bayfield, there is reason to think
that its greatest depth would not be overrated at two
hundred fathoms*, so that its bottom is, in some parts,

* Trans. of Lit. and Hist. Soe. of Quebec, vol. i. p. 5. 1829+

Ch: IV.] DELTAS OF LAKE SUPERIOR. 343.

nearly six hundred feet below the level of the Atlantic,
its surface about as much above it. There are appear-
ances in different parts of this, as of the other Canadian
lakes, leading us to infer that its waters formerly occu-
pied a much higher level than they reach at present;
for at a considerable distance from the present shores,
parallel lines of rolled stones and shells are seen rising
one above the other, like the seats of an amphi-
theatre. These ancient lines of shingle are exactly
similar to the present beaches in most bays, and they
often attain an elevation of forty or fifty feet above the
present level.
As the heaviest gales of wind do not raise the waters
more than three or four feet *, the elevated beaches
` must either be referred to the subsidence of the lake
at former periods, in consequence of the wearing down
of its barrier, or to the upraising of the shores by
earthquakes, like those which have produced similar
phenomena on the coast of Chili. The streams which
discharge their waters into Lake Superior are several
hundred in number, without reckoning those of smaller
size; and the quantity of water supplied by them is
many times greater than that discharged at the Falls
of St. Mary, the only outlet. The evaporation, there-
fore, is very great, and such as might be expected
from so vast an extent of surface.
On the northern side, which is encircled by primary
mountains, the rivers sweep in many large boulders

* Captain Bayfield remarks, that Dr. Bigsby, to whom we are
indebted for several communications respecting the geology of the
Canadian lakes, was misinformed by the fur traders in regar d to
the extraordinary height (twenty or thirty feet) to which he asserts
that the autumnal gales will raise the water of Lake Superior. —
Trans. of Lit. and Hist. Soc. of Quebec, vol. i. p. METSZI.

Q4

344: DELTAS OF THE BALTIC. [Book II.

with smaller gravel and sand, chiefly composed of
granitic and trap rocks. There are also currents in
the lake, in various directions, caused by the continued
prevalence of strong winds, and to their influence we
may attribute the diffusion of finer mud far and wide
over great areas; for, by numerous soundings made
during the late survey, it was ascertained that the
bottom consists generally of a very adhesive clay, con-
taining shells of the species at present existing in the
lake. When exposed to the air, this clay immedi-
ately becomes indurated in so great a degree, as to re-
quire a smart blow to break it. It effervesces slightly
with diluted nitric acid, and is of different colours in
different parts of the lake; in one district blue, in an-
other red, and in a third white, hardening into a sub-
stance resembling pipe-clay.* From these statements,
the geologist will not fail to remark how closely these
recent lacustrine formations in America resemble the
tertiary argillaceous and calcareous marls of lacustrine
origin in Central France. In both cases, many of the
genera of shells most abundant, as Lymnea and Plan-
orbis, are the same; and in regard to other classes of
organic remains, there must be the closest analogy, as
I shall endeavour more fully to explain when speaking
of the imbedding of plants and animals in recent
deposits.

DELTAS OF INLAND SEAS.

Baltic. — Having thus briefly considered some of
the lacustrine deltas now in progress, we may next
turn our attention to those of inland seas.

* Trans, of Lit. and Hist, Soc, of Quebec, vol. i. p. 5. 1829s

ch, IV] DELTA OF THE RHONE. 345

The shallowing and conversion into land of many
parts of the Baltic, especially the Gulfs of Bothnia and
Finland, have been demonstrated by a series of accu-
rate observations, for which we are in a great measure
indebted to the animated controversy which has been
kept up, since the middle of the last century, concern-
ing the gradual lowering of the level of the Baltic.
I shall revert to this subject when treating of the slow
and insensible upheaving of the land in certain parts of
Sweden, a movement which produces an apparent fall
in the level of the waters, both of the Baltic, and the
ocean.* It is only necessary to state in this place,
that the rapid gain of low tracts of land near Torneo,
Piteo and Luleo, near the head of the Gulf of Bothnia,
are due to the joint operation of two causes — the in-
flux of sediment from numerous rivers, and a slow and
general upward movement of the land itself, and bed
of the sea, at the rate of several feet in a century.

Delta of the Rhone.— We may now turn our at-
tention to some of the principal deltas of the Mediter-
ranean, for no other inland sea affords so many examples
of accessions of new lands at the mouths of rivers within
the records of authentic history. The lacustrine delta
of the Rhone in Switzerland has already been con-
sidered, and its contemporaneous marine delta may
now be described. Scarcely has the river passed out of
the Lake of Geneva, before its pure waters are again
filled with sand and sediment by the impetuous Arve;
descending from the highest Alps, and bearing along
in its current the granitic detritus annually brought

* Since writing the third edition, I have visited Sweden, and,
removed the doubts which I before entertained and expressed re~
specting the alleged gradual elevation of the land in Scandinavia.,
— See Book ii. chap. xvii.

QS

8346 DELTA OF THE RHONE. [Book if.

down by the glaciers of Mont Blanc. The Rhone
afterwards receives vast contributions of transported
matter from the Alps of Dauphiny, and the primary
and volcanic mountains of Central France; and when
at length it enters the Mediterranean, it discolours
the blue waters of that sea with a whitish sediment,
for the distance of between six and seven miles,
throughout which space the current of fresh water
is perceptible.

Proofs of its increase since historical periods.— Strabo’s
description of the delta is so inapplicable to its present
configuration, as to attest a complete alteration in the
physical features of the country since the Augustan
age. It appears, however, that the head of the delta,
or the point at which it begins to ramify, has remained
unaltered since the time of Pliny, for he states that
the Rhone divided itself at Arles into two arms. This
is the case at present ; one of the branches being now
called Le Petit Rhône, which is again subdivided be-
fore entering the Mediterranean. The advance of the
base of the delta, in the last eighteen centuries, is
demonstrated by many curious antiquarian monu-
ments.. The most striking of these is the great detour
made by the old Roman road from Ugernum to
Beziers (part of the high road between Aix, Aque
Sextie, and Nismes, Nemausus). It is clear that,
when this was first constructed, it was impossible
to pass in a direct line as now, across the delta, and
that either the sea or marshes intervened in a tract
now consisting of terra firma.* Astruc also remarks,
that all the places on low lands, lying to the north of
the old Roman road between Nismes and Beziers,

* Mém. d’ Astruc, cited by Von Hoff, vol. i. p. 228-

Ch. IV. DELTA OF THE RHONE. SAT.

have names of Celtic origin, evidently given to them
by the first inhabitants of the country ; whereas, the
places lying south of that road, towards the sea, have
names of Latin derivation, and were clearly founded
after the Roman language had been introduced.

Another proof, also, of the great extent of land
which has come into existence since the Romans con-
quered and colonized Gaul, is derived from the fact,
that the Roman writers never mention the thermal
waters of Balaruc in the delta, although they were well
acquainted with those of Aix, and others still more
distant, and attached great importance to them, as
they invariably did to all hot springs: The waters of
Balaruc, therefore, must have formerly issued under
the sea— a common phenomenon on the borders of the
Mediterranean ; and on the advance of the delta they
continued to flow out through the new deposits.

Among the more direct proofs of the increase of land,
we find that Mese, described under the appellation of
Mesua Collis by Pomponius Mela*, and stated by him
to be nearly an island, is now far inland. Notre Dame
des ‘Ports, also, was a harbour in 898, but. is now a
league from the shore. Psalmodi was an island in
815, and is now two leagues from the sea. Several
old lines of towers and sea-marks occur at different
distances from the present coast, all indicating the
successive retreat of the sea, for each line has in its
turn become useless to mariners; which may well be
conceived, when we state that the tower of Tignaux,
erected on the shore so late as the year 1737, is
already a French mile remote from it. +

* Lib. II. c. v:
+ Bouche, Chorographie et Hist. de Provence, vol. i. p. 23.,
cited by Von Hoff, vol. i. p. 290.
Q6

B48 DELTA OF THE RHONE. [Book HH.

By the confluence of the Rhone and the currents of
the Mediterranean, driven by winds from the south,
sand-bars are often formed across the mouths of the
river: by these means considerable spaces become
divided off from the sea, and subsequently from the
river also, when it shifts its channels of efflux. As
some of these lagoons are subject to the occasional
ingress of the river when flooded, and of the sea
during storms, they are alternately salt and fresh.
Others, after being filled with salt water, are often
lowered by evaporation till they become more salt
than the sea ; and it has happened, occasionally, that
a considerable precipitate of muriate of soda has taken
place in these natural salterns. During the latter part
of Napoleon’s career, when the excise laws were en-
forced with extreme rigour, the police was employed
to prevent such salt from being used. The fluviatile
and marine shells enclosed in these small lakes often
live together in brackish water; but the uncongenial
nature of the fluid usually produces a dwarfish size,
and sometimes gives rise to strange varieties in form
and colour. .

Captain Smyth, in the late survey of the coast of
the Mediterranean, found the sea, opposite the mouth
of the Rhone, to deepen gradually from four to forty
fathoms, within a distance of six or seven miles, over
which the discoloured fresh water extends; so that
the inclination of the new deposits must be too slight
to be appreciable in such an extent of section as a
geologist usually obtains in examining ancient form-
ations. When the wind blew from the south-west, the
ships employed in the survey were obliged to quit
their moorings ; and when they returned, the new
sand-banks.in the delta were found covered over with

Ch, 1V.J DELTA OF THE RHONE.

a great abundance of marine shells. By this means,
we learn how occasional beds of drifted marine shells
may become interstratified with fresh-water strata at
a river’s mouth.

Stony nature of its deposits.— That a great propor-
tion, at least, of the new deposit in the delta of the
Rhone, consists of rock, and not of loose incoherent
matter, is perfectly ascertained. In the Museum at
Montpellier is a cannon taken up from the sea near
the mouth of the river, imbedded in a crystalline cal-
careous rock. Large masses, also, are continually taken
up of an arenaceous rock, cemented by calcareous
matter, including multitudes of broken shells of recent
species. The observations lately made on this subject
corroborate the former statement of Marsilli, that the
earthy deposits of the coast of Languedoc form a
stony substance, for which reason he ascribed a certain
bituminous, saline, and glutinous nature to the sub-
stances brought down with sand by the Rhone.* If
the number of mineral springs charged with carbonate
of lime which fall into the Rhone and its feeders in
different parts of France be considered, we shall feel
no surprise at the lapidification of the newly deposited
sediment in this delta. It should be remembered, that
the fresh water introduced by rivers, being lighter
than the water of the sea, floats over the latter, and
remains upon the surface for a considerable distance.
Consequently, it is exposed to as much evaporation as
the waters of a lake; and the area over. which the
river-water is spread, at the junction of great rivers
and the sea, may well be compared, in point of extent,
to that of considerable lakes.

* Hist. Phys. de la Mer.

350 DELTA OF THE PO. [Book 1.

Now, it is well known, that so great is the quantity
of water carried off by evaporation in some lakes, that
it is nearly equal to the water flowing in ; and in some
inland seas, as the Caspian, it is quite equal. We
may, therefore, well suppose, that, in cases where a
strong current does not interfere, the greater portion
not only of the matter held mechanically in suspension,
but of that also which is in chemical solution, may be
precipitated at no great distance from the shore. When
these finer ingredients are extremely small in quantity,
they may only suffice to supply crustaceous animals,
corals, and marine plants, with the earthy particles
necessary for their secretions ; but whenever it is in
excess (as generally happens if the basin of a river lie
partly in a district of active or extinct volcanos), then
will solid deposits be formed, and the shells will at
once be included in a rocky mass.

Delta of the Po.—The Adriatic presents a great
combination of circumstances favourable to the rapid
formation of deltas—a gulf receding far into the land
—a sea without tides or strong currents, and the
influx of two great rivers, the Po and the Adige,
besides numerous minor streams, draining on the one
side a great crescent of the Alps, and on the other
some of the loftiest ridges of the Apennines. From
the northernmost point of the Gulf of Trieste, where
the Isonzo enters, down to the south of Ravenna,
there is an uninterrupted series of recent accessions
of land, more than one hundred miles in length,
which, within the last two thousand years, have in-
creased from two to twenty miles in breadth, The
Isonzo, Tagliamento, Piave, Brenta, Adige, and Po,
besides many other inferior rivers, contribute to the
advance of the coast-line, and to the shallowing of the

Ch. IV.J DELTA OF THE PO. 351

gulf. The Po and the Adige may now be considered
as entering by one common delta, for two branches of
the Adige are connected with arms of the Po.

In consequence of the great concentration of the
flooded waters of these streams since the system of
embankment became general, the rate of encroach-
ment of the new land upon the Adriatic, especially at
that point where the Po and Adige enter, is said to
have been greatly accelerated. Adria was a seaport
in the time of Augustus, and had, in ancient times,
given its name to the gulf; it is now about twenty —
Italian miles inland. Ravenna was also a seaport, and
is now about four Italian miles from the main sea.
Yet even before the practice of embankment was in-
troduced, the alluvium of the Po advanced with rapidity
on the Adriatic; for Spina, a very ancient city, ori-
ginally built in the district of Ravenna, at the mouth
of a great arm of the Po, was, so early as the com-
mencement of our era, eleven Italian miles distant
from the sea.*

The greatest depth of the Adriatic, between Dal-
matia and the mouths of the Po, is twenty-two fathoms;
put a large part of the Gulf of Trieste andthe Adriatic,
opposite Venice, is less than twelve fathoms deep.
Farther to the south, where it is less affected by the
influx of great rivers, the gulf deepens considerably.
Donati, after dredging the bottom, discovered the new
deposits to consist partly of mud and partly of rock,
the rock being formed of calcareous matter, incrusting
shells. He also ascertained, that particular species of
testacea were grouped together in certain places, and

* See Brocchi on the various writers on this subject, Conch.
Foss. Subap., vol. i. p. 118.

352 DELTA OF THE PO, [Book If.

were becoming slowly incorporated with the mud, or
calcareous precipitates.* Olivi, also, found some de-
posits of sand, and others of mud, extending half way
across the gulf; and he states that their distribution
along the bottom was evidently determined by the
prevailing current.t It is probable, therefore, that
the finer sediment of all the rivers at the head of the
Adriatic may be intermingled by the influence of the
current ; and all the central parts of the gulf may be
considered as slowly filling up with horizontal deposits,
similar to those of the Subapennine hills, and contain-
ing many of the same species of shells. The Po
merely introduces at present fine sand and mud ; for it
carries no pebbles farther than the spot where it joins
the Trebia, west of Piacenza. Near the northern
borders of the basin, the Isonzo, Tagliamento, and
many other streams, are forming immense beds of
sand and some conglomerate ; for here some high
mountains of Alpine limestone approach within a few
miles of the sea.

In the time of the Romans, the hot-baths of Mon-
falcone were on one of several islands of Alpine lime-
stone, between which and the mainland, on the north,
was a channel of the sea, about a mile broad. This
channel is now converted into a grassy plain, which
surrounds the islands on all sides. Among the nu-
merous changes on this coast, we find that the present
channel of the Isonzo is several miles to the west of
its ancient bed, in part of which, at Ronchi, the old
Roman bridge which crossed the Via Appia was lately
found buried in fluviatile silt.

Notwithstanding the present shallowness of the

* See Brocchi, vol. i. p. 39. t Ibid., vol. ii. p. 94.

Ch. 1V.] DELTA OF THE NILE. 353

Adriatic, it is highly probable that its original depth
was very great ; for if all the low alluvial tracts were
taken away from its borders and replaced by sea, the
high land would terminate in that abrupt manner
which generally indicates, in the Mediterranean, a
great depth of water near the shore, except in those
spots where sediment imported by rivers and currents
has diminished the depth. Many parts of the Medi-
terranean are now ascertained to be above two thou-
sand feet deep, close to the shore, as between Nice
and Genoa; and even sometimes six thousand feet, as
near Gibraltar. When, therefore, we find, near Parma,
and in other districts in the interior of the Italian pe-
ninsula, beds of horizontal tertiary marl attaining a
thickness of about two thousand feet, or when we dis-
cover strata of inclined conglomerate, of the same age,
near Nice, measuring above a thousand feet in thick-
ness, and extending seven or eight miles in length, we
behold nothing which the analogy of the deltas in the
Adriatic might not lead us to anticipate.

Delta of the Nile. —That Egypt was “ the gift of the
Nile,” was the opinion of her priests before the time
of Herodotus; but we have no authentic memorials
for determining, with accuracy, the dates of successive
additions made to the habitable surface of that country.
The configuration and composition of the low lands
leave no room for doubt, says Rennell, that “ the sea
once washed the base of the rocks on which the pyra-
mids of Memphis stand, the present base of which is
washed by the inundation of the Nile, at an elevation
of 70 or 80 feet above the Mediterranean. But when
we attempt to carry back our ideas to the remote
period when the foundation of the delta was first laid,
we are lost in the contemplation of so vast an interval

354 DELTA OF THE NILE. [Book II.

of time.”* We know that the base of the delta has
been considerably modified since the days of Homer.
The ancient geographers mention seven principal
mouths of the Nile, of which the most eastern, the
Pelusian, has been entirely silted up, and the Men-
desian, or Tanitic, has disappeared. The Phatnitic
mouth, and the Sebenitic, have been so altered, that
the country immediately about them has little resem-
blance to that described by the ancients. The Bolbi-
tine mouth has increased in its dimensions, so as to
cause the city of Rosetta to be at some distance from
the sea.

The alterations produced around the Canopic mouth
are also important. The city Foah, which, so late as
the beginning of the fifteenth century, was on this
embouchure, is now more than a mile inland. Cano-
pus, which, in the time of Scylax, was a desolate
insular rock, has been connected with the firm land;
and Pharos, an island in times of old, now belongs to
the continent. Homer says, its distance from Egypt
was one day’s voyage by sea.+ That this should
have been the case in Homer's time, Larcher and
others have, with reason, affirmed to be in the highest
degree improbable: but Strabo has judiciously antici-
pated their objections, observing, that Homer was
probably acquainted with the gradual advance of the
land on this coast, and availed himself of this pheno-
menon to give an air of higher antiquity to the remote
period in which he laid the scene of his poem.t The
Lake Mareotis, also, together with the canal which

* Geog. Syst. of Herod. vol. ii. p. 107.
t Odys., book iv. v. 355.

# Lib. I. Parti. pp. 80. 9, Consult Von Hoff, vol. i. p. 244:

Ch. IVI DELTA OF THE NILE. 355

connected it with the Canopic arm of the Nile, has
been filled with mud, and is become dry. Herodotus
observes, “ that the country round Memphis seemed
formerly to have been an arm of the sea gradually
filled by the Nile, in the same manner as the Mean-
der, Achelous, and other streams, had formed deltas.
Egypt, therefore, he says, like the Red Sea, was
once a long narrow bay, and both gulfs were separ-
ated by a small neck of land. If the Nile, he adds,
should by any means have an issue into the Arabian
Gulf, it might choke it up with earth in twenty thou-
sand, or even, perhaps, in ten thousand years; and
why may not the Nile have filled with mud a still
greater gulf in the space of time which has passed
before our age?” *

Mud of the Mile. — The analysis of the mud of the
Nile gives nearly one half of argillaceous earth, and
about one fourth of carbonate of lime, nearly one
tenth of carbon, the remainder consisting of water,
silex, oxide of iron, and carbonate of magnesia.t

The depth of the Mediterranean is about twelve
fathoms at a small distance from the shore of the
delta; it afterwards increases gradually to 50, and then
suddenly descends to 380 fathoms, which is, perhaps,
the original depth of the sea where it has not been
rendered shallower by fluviatile matter. ‘The progress
of the delta in the last two thousand years affords,
perhaps, no measure for estimating its rate of growth
when it was an inland bay, and had not yet protruded
itself beyond the coast-line of the Mediterranean.
A powerful current now sweeps along the shores of

* Euterpe, XI.
t Girard, Mém. sur l’Egypte, tom i. pp. 348. 382.

356 DELTA OF THE NILE. [Book II.

Africa, from the Straits of Gibraltar to the prominent
convexity of Egypt, the western side of which is
continually the prey of the waves; so that not only
are fresh accessions of land checked, but ancient parts
of the delta-are carried away. By this cause Canopus
and some other towns have been overwhelmed: but
to this subject I shall again refer when speaking of
tides and currents.

CHAPTER V.
OCEANIC DELTAS.

Oceanic deltas — Deltas of the Ganges and Burrampooter — Its
size — Rate of advance, and nature of its deposits — Formation
and destruction of islands — Abundance of crocodiles — In«
undations — Delta of the Mississippi (p. 364.) — Deposits of
drift wood — Gradual filling up of the Yellow Sea — Estimate
of the quantity of mud carried down by the Ganges — Form-
ation of valleys illustrated by the growth of deltas— Grouping
of new strata in general OB Convergence of deltas —
Conglomerates — Various causes of stratification — Direction
of laminze — Remarks on the interchange of land and sea.

Tur remaining class of deltas are those in which
rivers, on entering the sea, are exposed to the influ-
ence of the tides. In this case it frequently happens that
an estuary is produced, or negative delta, as Rennell
termed it, where, instead of any encroachment of the
land upon the sea, the ocean enters the river’s mouth,
and penetrates into the land beyond the general coast-
line. Where this happens, the tides and currents are
the predominating agents in the distribution of trans-
ported sediment. The phenomena, therefore, of such
estuaries, will be treated of when the movements of
the ocean come under consideration. But whenever
the volume of fresh water is so great as to counteract
and almost neutralize the force of tides and currents,
and in all cases where these agents have not sufficient
power to remove to a distance the whole of the sedi-

358 DELTA OF THE GANGES. ~ [Book 11.

ment periodically brought down by rivers, oceanic
deltas are produced. Of these, I shall now select
a few illustrative examples.

Delta of the Ganges. —The Ganges and the Bur-
rampooter descend, from the highest mountains in the
world, into a gulf which runs 225 miles into the con-
tinent. The Burrampooter is somewhat the larger
river of the two; but it first takes the name of the
Megna when joined by a smaller stream so called, and
afterwards loses this second name on its union with
the Ganges, at the distance of about forty miles from
the sea. The area of the delta of the Ganges (with-
out including that of the Burrampooter, which has
now become conterminous) is considerably more than
double that of the Nile; and its head commences at a
distance of 220 miles, in a direct line from the sea. Its
base is two hundred miles in length, including the space
occupied by the two great arms of the Ganges which
bound it on either side. That part of the delta which
borders on the sea is composed of a labyrinth of rivers ,
and creeks, all filled with salt water, except those im-
mediately communicating with the principal arm of
the Ganges. This tract alone, known by the name of
the Woods, or Sunderbunds, a wilderness infested by
tigers and alligators, is, according to Rennell, equal in
extent to the whole principality of Wales.*

On the sea-coast there are eight great openings, each
of which has evidently, at some ancient period, served
in its turn as the principal channel of dischar ge. Al-
though the flux and reflux of the tide extend even to
the head of the delta when the river is low; yet, when

* Account of the Ganges and Burrampooter Rivers, by Major
Rennell, Phil. Trans. 1781.

Ch. V] DELTA OF THE GANGES. 359

it is periodically swollen by tropical rains, the velocity
of the stream counteracts the tidal current, so that,
except very near the sea, the ebb and flow become
insensible. During the flood season, therefore, the
Ganges almost assumes the character of a river enter-
ing a lake or inland sea ; the movements of the ocean
being then subordinate to the force of the river, and
only slightly disturbing its operations. The great gain
of the delta in height and area takes place during the
inundations ; and, during other seasons of the year, the
ocean makes reprisals, scouring out the channels, and
sometimes devouring rich alluvial plains.

So great is the quantity of mud and sand poured by
the Ganges into the gulf in the flood season, that the
sea only recovers its transparency at the distance of
sixty miles from the coast. The general slope, there-
fore, of the new strata must be extremely gradual.
By the charts recently published, it appears that there
is a gradual deepening from four to about sixty fathoms,
as we proceed from the base of the delta to the dis-
tance of about one hundred miles into the Bay of
Bengal. At some few points seventy, or even one
hundred, fathoms are obtained at that distance.

One remarkable exception, however, occurs to the
regularity of the shape of the bottom ; for, opposite the
middle of the delta, at the distance of thirty or forty
miles from the coast, is a nearly circular space called
the “swatch of no ground,” about fifteen miles in dia-
meter, where soundings of 100, and even 130, fathoms
fail to reach the bottom. This phenomenon is the more
extraordinary, since the depression occurs within five
miles of the line of shoals ; and not only do the waters
charged with Gangetic sediment pass over it con-
tinually ; but, during the monsoons, the sea, loaded

360 DELTA OF THE GANGES. [Book IT.

with mud and sand, is beaten back in that direction
towards the delta. As the mud is known to extend
for eighty miles farther into the gulf, we may be as-
sured that, in the course of ages, the accumulation of
strata in “ the swatch” has been of enormous thick-
ness; and we seem entitled to deduce, from the pre-
sent depth at the spot, that the original inequalities of
the bottom of the Bay of Bengal were on a grand
scale, and comparable to those of the main ocean.

Opposite the mouth of the Hoogly river, and imme-
diately south of Sangor Island, four miles from the
nearest land of the delta, a new islet was formed about
twenty years ago, called Edmonstone Island, on the
centre of which a beacon was erected as a land-mark
in 1817. In 1818 the island had become two miles
long and half a mile broad, and was covered with vege-
tation andshrubs. Some houses were then built upon
it, and in 1820 it was used as a pilot station. The
severe gale of 1823 divided it into two parts, and so
reduced its size as to leave the beacon standing out
in the sea, where after remaining seven years it was
washed away. Atlength the islet has been converted
by successive storms into a sand-bank.

Although there is evidence of gain at some points
the general progress of the coast is very slow ; for the
tides, which rise from thirteen to sixteen feet, are
actively employed in removing the alluvial matter, and
diffusing it over a wide area. The new strata consist
entirely of sand and fine mud; such, at least, are the
only materials which are exposed to view in regular
beds on the banks of the numerous creeks. No sub-
stance so coarse as gravel occurs in any part of the
delta, nor nearer the sea than 400 miles. It should
be observed, however, that the superficial alluvial

Ch, V.] DELTA OF THE GANGES. _ 361

beds, which are thrown down rapidly from turbid waters
during the floods, may be very distinct from those de-
posited at a greater distance from the shore, where
crystalline precipitates, perhaps, are forming, on the
evaporation of so great a surface, exposed to the rays
of a tropical sun. The separation of sand and other
matter, held in mechanical suspension, may take place
where the waters are in motion; but mineral ingre-
dients, held in chemical solution, would naturally be
carried toa greater distance, where they may aid in
the formation of corals and shells, and, in part, perhaps,
become the cementing principle of rocky masses.

A well was sunk at Fort William, Calcutta, in the
hope of obtaining water, through beds of adhesive clay,
to the depth of 146 feet. A bed of yellow sand was
then entered, and at the depth of 152 feet another
stratum of clay.*

Islands formed and destroyed. — Major R. H. Cole-
brooke, in his account of the course of the Ganges,
relates examples of the rapid filling up of some of its
branches, and the excavation of new channels, where
the number of square miles of soil removed in a short
time (the column of earth being 114 feet high) was
truly astonishing. Forty square miles, or 25,600 acres,
are mentioned as having been carried away, in one
place in the course of a few years. + The immense
transportation of earthy matter by the Ganges and
Megna is proved by the great magnitude of the islands
formed in their channels during a period far short of
that of a man’s life. Some of these, many miles in
extent, have originated in large sand-banks thrown up

* See India Gazette, June 9. 1831.
+ Trans. of the Asiatic Society, vol. vil. p: 14,

VOL. I. R

362 DELTA OF THE GANGES. [Book II.

round the points at the angular turning of the river,
and afterwards insulated by breaches of the stream-
Others, formed in the main channel, are caused by
some obstruction at the bottom. A large tree, or a
sunken boat, is sometimes sufficient to check the current,
and cause a deposit of sand, which accumulates till it
usurps a considerable portion of the channel. The
river then borrows on each side to supply the deficiency
in its bed, and the island is afterwards raised by fresh
deposits during every flood. In the great gulf below
Luckipour, formed by the united waters of the Ganges
and Burrampooter (or Megna), some of the islands,
says Rennell, rival in size and fertility the Isle of
Wight. While the river is forming new islands in one
part, it is sweeping away old ones in others. Those
newly formed are soon overrun with reeds, long grass,
the Tamarix Indica, and other shrubs, forming impe-
netrable thickets, where tigers, buffaloes, deer, and
other wild animals, take shelter. It is easy, therefore,
to perceive, that both animal and vegetable remains
must continually be precipitated into the flood, and
sometimes become imbedded in the sediment which
subsides in the delta.

Two species of crocodiles, of distinct genera, abound
in the Ganges and its tributary and contiguous waters ;
and Mr. H. T. Colebrooke informs me, that he has
seen both kinds in places far inland, many hundred
miles from the sea. The Gangetic crocodile, or
Gavial (in correct orthography, Garial), is confined to
the fresh water, but the common crocodile frequents
both fresh and salt; being much larger and fiercer in
salt and brackish water. These animals swarm in the
brackish water along the line of sand-banks where the
advance of the delta is most rapid. Hundreds of

Ch. V.J DELTA OF THE GANGES. 363

them are seen together in the creeks of the delta, or
basking in the sun on the shoals without. They will

attack men and cattle, destroying the natives when

bathing, and tame and wild animals which come to
drink. “I have not unfrequently,” says Mr. Cole-
brooke, “ been witness to the horrid spectacle of a
floating corpse seized by a crocodile with. such avidity,
that he half emerged above the water with his prey in
his mouth.” The geologist will not fail to observe how
peculiarly the habits and distribution of these saurians
expose them to become imbedded in the horizontal
strata of fine mud, which are annually deposited over
many hundred square miles in the Bay of Bengal.
The inhabitants of the land, which happen to be
drowned or thrown into the water, are usually devoured
by these voracious reptiles; but we may suppose the
remains of the saurians themselves to be continually
entombed in the new formations.

Inundations. — It sometimes happens, at the season
when the periodical flood is at its height, that a strong
gale of wind, conspiring with a high spring-tide,
checks the descending current of the river, and gives
rise to most destructive inundations. From this cause,
in the year 1763, the waters at Luckipour rose six
feet above their ordinary level, and the inhabitants of
a considerable district, with their houses and cattle,
were totally swept away.

The population of all oceanic deltas are particularly
exposed to suffer by such catastrophes, recurring at
considerable intervals of time; and we may safely
assume that such tragical events have happened again
and again since the Gangetic delta was inhabited by
man. If human experience and forethought cannot

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864 DELTA OF THE MISSISSIPPI. [Book II.

always guard against these calamities, still less can the
inferior animals avoid them; and the monuments of
such disastrous inundations must be looked for in great
abundance in strata of all ages, if the surface of our
planet has always been governed by the same laws.
When we reflect on the general order and tranquillity
that reigns in the rich and populous delta of Bengal,
notwithstanding the havoc occasionally committed by
the depredations of the ocean, we perceive how un-
necessary it is to attribute the imbedding of successive
races of animals in older strata to extraordinary energy
in the causes of decay and reproduction in the infancy
of our planet, or to those general catastrophes and
sudden revolutions resorted to by some theorists.
Delta of the Mississippi.—As the delta of the
Ganges may be considered a type of those formed on
the borders of the ocean, it will be unnecessary to
accumulate examples of others on a no less magnificent
scale, as, for example, at the mouths of the Orinoco
and Amazon. To these, however, I shall revert by
and by, when treating of the agency of currents. The
tides in the Mexican Gulf are so feeble, that the delta
of the Mississippi has somewhat of an intermediate
character between an oceanic and mediterranean delta.
A long narrow tongue of land is protruded, consisting
simply of the banks of the river, wearing precisely the
same appearance as in the inland plains during the
periodical mundations, when nothing appears above
water but the higher part of the sloping glacis before
described.* This tongue of land has advanced many
leagues since New Orleans was built. Great sub-
marine deposits are also in progress, stretching far and

* Chapter II.

Ch. V.] DELTA OF THE MISSISSIPPI. 365

wide over the bottom of the sea, which has become
extremely shallow, not exceeding ten fathoms in
depth. Opposite the mouth of the Mississippi large
rafts of drift trees brought down every spring, are
matted together into a net-work many yards in thick-
ness, and stretching over hundreds of square leagues.*
They afterwards become covered over with a fine mud,
on which other layers of trees are deposited the year
following, until numerous alternations of earthy and
vegetable matter are accumulated.
Alternation of deposits. — An observation of Darby,
in regard to the strata composing part of this delta,
deserves attention. In the steep banks of the Atcha-
. falaya, an arm of the Mississippi before alluded to in
our description of “ the raft,” the following section is
observable at low water: — first, an upper stratum,
consisting invariably of blueish clay, common to the
banks of the Mississippi; below this a stratum of red
ochreous earth, peculiar to Red River, under which
the blue clay of the Mississippi again appears ; and this
arrangement is constant, proving, as that geographer
remarks, that the waters of the Mississippi and the
Red River occupied alternately, at some former pe-
riods, considerable tracts below their present point of
union.+ Such alternations are probably common in
submarine spaces situated between two converging
deltas ; for, before the two rivers unite, there must
almost always be a certain period when an intermediate
tract will by turns be occupied and abandoned by the
waters of each stream ; since it can rarely happen that
the season of highest flood will precisely correspond in

* Captain Hall’s Travels in North America, vol. iii. p. 338. —
See also above, p. 286. :
+ Darby’s Louisiana, p. 103.
RD

366 PROPORTION OF SEDIMENT [Book 11.

each. In the case of the Red River and Mississippi,
which carry off the waters from countries placed under
widely distant latitudes, an exact coincidence in the
time of greatest inundation is very improbable.

CONCLUDING REMARKS ON DELTAS.

Quantity of sediment in river water.—Very few
satisfactory experiments have as yet been made, to
enable us to determine, with any degree of accuracy,
the mean quantity of earthy matter discharged annually
into the sea by some one of the principal rivers of the
earth. Hartsoeker computed the Rhine to contain in
suspension, when most flooded, one part in a hundred of
mud in volume * ; but it appears from two sets of experi-
ments, recently made by Mr. Leonard Horner, at Bonn,
that +s455th would have been a nearer approxima-
tion to the truth.+ Sir George Staunton inferred from
several observations, that the water of the Yellow River
in China, contained earthy matter in the proportion of
one part to two hundred, and he calculated that it
brought down in a single hour two million cubic feet
of earth, or forty-eight million daily; so that, if the
Yellow Sea be taken to be 120 feet deep, it would
require seventy days for the river to convert an English
square mile into firm land, and 24,000 years to turn
the whole sea into terra firma, assuming it to be
125,000 square miles in area.t Manfredi, the ‘cele-
brated Italian hydrographer, conceived the average
proportion of sediment in all the running water on the

* Comment. Bonon., vol. ii. part. i. ps 237.
+ Edin. New Phil. Journ., Jan. 1835.
. 4 Staunton’s Embassy to China, Lond. 1797, 4to. vol. ii. p. 408.

Ch. V.] IN RIVER WATER. 367
globe, which reached the sea, to be T75» and he
imagined that it would require a thousand years for
the sediment carried down to raise the general level
of the sea about one foot. Some writers, on the con-
trary, as De Maillet, have declared the most turbid
waters to contain far less sediment. One of the most
extraordinary statements is that of Major Rennell, in
his excellent paper, before referred to, on the delta of
the Ganges. “ A glass of water,” he says, “ taken out
of this river when at its height, yields about one part
in four of mud. No wonder, then,” he adds, “ that
the subsiding waters should quickly form a stratum of
earth, or that the delta should encroach on the sea!” *
There must certainly be some mistake, perhaps a
misprint, in the statement in the Phil. Trans.; and
some have conjectured that the learned hydrographer
meant one part in four hundred of mud. In former
- editions of this work, I expressed my regret that so
much inconsistency and contradiction should be found
in the statements and speculations relative to this in-
teresting subject ; and I endeavoured to point out the
high geological importance of reducing to arithmetical
computation the aggregate amount of solid matter
transported by certain large rivers to the sea. The
deficiency of data has now been, in some degree, re-
moved by the labours of the Rev. Mr. Everest, who has
instituted a series of observations “ On the earthy
matter brought down by the Ganges” at Ghaziptr,
above Calcutta.t
The first step to be made in all such calculations is to
* Phil. Trans. 1781.
+ Journ. of Asiatic Soc., No. 6. p. 238. June, 1832. See
also Mr. Prinsep, Gleanings in Science, vol. iii, p- 185.

R 4

368 PROPORTION OF SEDIMENT [Book II.

ascertain the average volume of water passing annually
down the channel of a river. This might easily be
accomplished if the breadth, depth, and velocity of
a stream were constant and uniform throughout the
year; but as all these conditions are liable to vary
according to the seasons, the problem becomes ex-
tremely complex. In the Ganges, as in other rivers
in hot climates, there are periodical inundations, during
which by far the greatest part of the annual discharge
takes place; and the most important point, therefore,
to determine, is the mean breadth, depth, and velocity
of the stream during this period.

Mr. Everest found that, in 1831, the number of
cubic feet of water discharged by the Ganges per
second was, during the

Rains, (4 months) -~ - 494,208
Winter, (5 months) - - 71,200

Hot weather, (3 months) - 36,330

so that we may state in round numbers, that 500,000
cubic feet flow down during the four months of the
flood season, from June to September, and only 100,000
during the remaining eight months.

Having obtained the volume of water, we have next
to inquire what is the proportion of solid matter con-
tained in it; and for this purpose, a definite quantity,
as, for example, a quart, is taken from the river on
different days, sometimes from the middle of the cur-
rent, and sometimes nearer the banks. This water is
then evaporated, the solid residuum weighed, and the
mean quantity of sediment thus ascertained, through-
out the rainy season. The same observations must
then be repeated for the other portions of the year.

Ch. V.J IN RIVER WATER. 369

In computing the quantity of water, Mr. Everest
made no allowance for the decreased velocity of the
stream near the bottom, presuming that it is com-
pensated by the increased weight of matter held in
suspension there. Probably the amount of sediment
is by no means exaggerated by this circumstance ; but
rather under-rated, as the heavier grains of sand,
which can never rise into the higher parts of the
stream, are drifted along the bottom.

Now the average quantity of solid matter suspended
in the water during the: rains was, by weight =4,th
part; but, as the water is about one half the specific
gravity of the dried mud, the solid matter discharged
is =1,th part in bulk, or 577 cubic feet per second.
This gives a total of 6,082,041,600 cubic feet for the
discharge in the 122 days of the rain. The proportion
of sediment in the waters at other seasons was com-
paratively insignificant, the total amount during the
five winter months being only 247,881,600 cubic feet,
and during the three months of hot weather, 38,154,240
cubic feet. The total annual discharge, then, would
be 6,368,077,440 cubic feet.

In order to give some idea of the magnitude of this
result, we will assume that the specific gravity of the
dried mud is only one half that of granite (it would.
however, be more); in that case, the earthy matter
discharged in a year would equal 3,184,038,720 cubic
feet of granite. Now about 12 cubic feet of granite
weigh one ton; and it is computed that the great
Pyramid of Egypt, if it were a solid mass of granite.
would weigh about 6,000,000 tons. ‘The mass of
matter, therefore, carried down annually, would, ac-
cording to this estimate, more than equal in weight

R 5

aera

370 SEDIMENT IN RIVER WATER. [Book II.

and bulk forty-two of the great pyramids of Egypt,
and that borne down in the four months of the rains
would equal forty pyramids. But if, without any con-
jecture as to what may have been the specific gravity
of the mud, we attend merely to the weight of solid
matter actually proved by Mr. Everest to have been
contained in the water, we find that the number of
tons weight which passed down in the 122 days of the
rainy season was 339,413,760, which would give the
weight of fifty-six pyramids and a half; and in the
whole year 355,361,464 tons, or nearly the weight of
sixty pyramids.

The base of the great Pyramid of Egypt covers
eleven acres, and its perpendicular height is about five
hundred feet. It is scarcely possible to present any
picture to the mind which will convey an adequate
conception of the mighty scale of this operation, so
tranquilly and almost insensibly carried on by the
Ganges, as it glides through its alluvial plain. It may,
however, be stated, that if a fleet of more than eighty
Indiamen, each freighted with about 1400 tons weight
of mud, were to sail down the river every hour of
‘every day and night for four months continuously, they
would only transport from the higher country to the
‘Sea a mass of solid matter equal to that borne down
by the Ganges in the flood season. Or the exertions
of a fleet of about 2000 such ships going down daily
with the same burden, and discharging it into the
gulf, would be no more than equivalent to the opera-
tions of the great river. Yet, in addition to this, it is
probable that the Burrampooter conveys annually as
much solid matter to the sea as the Ganges.

The most voluminous current of lava which has

Ch. V.J GROUPING OF STRATA IN DELTAS. Onl.

flowed from Etna within historical times was that of
1669. Ferrara, after correcting Borrelli’s estimate,
calculated the quantity of cubic yards of lava in this
current at 140,000,000. Now, this would not equal
in bulk one fifth of the sedimentary matter which is
carried down in a single year by the Ganges, according
to the estimate above explained; so that it would
require five grand eruptions of Etna to transfer a mass
of lava from the subterranean regions to the surface,
equal in volume to the mud carried down to the sea in
one year by a single river in Bengal.

Grouping of Strata in Deltas. — The changes which,
have taken place in deltas, even since the times of
history, may suggest many important considerations in
regard to the manner in which subaqueous sediment
is distributed. Notwithstanding frequent exceptions,
arising from the interference of a variety of causes,
there are some general laws of arrangement which
must evidently hold good in almost all the lakes and
seas now filling up. If a lake, for example, be
encircled on two sides by lofty mountains, receiving
-from them many rivers and torrents of different sizes,
and if it be bounded on the other sides, where the
surplus waters issue, by a comparatively low country,
it is not difficult to define some of the leading geological
features which must characterize the lacustrine form-
ation, when this basin shall have been gradually con-
verted into dry land by the influx of sediment. The
strata would be divisible into two principal groups :
the older comprising those deposits which originated
on the side adjoining the mountains, where numerous
deltas first began to form ; and the newer group con-
sisting of beds deposited in the more central parts
of the basin, and towards the side farthest from the

R 6

B72 GROUPING OF STRATA [Book II.

mountains. The following characters would form the
principal marks of distinction between the strata in
each series. The more ancient system would be com-
posed, for the most part, of coarser materials, con-
taining many beds of pebbles and sand, often of great
thickness, and sometimes dipping at a considerable
angle. These, with associated beds of finer ingre-
dients, would, if traced round the borders of the basin,
be seen to vary greatly in colour and mineral com-
position, and would also be very irregular in thickness.
The beds, on the contrary, in the newer group, would
consist of finer particles, and would be horizontal, or
very slightly inclined. Their colour and mineral com-
position would be very homogeneous throughout large
areas, and would differ from almost all the separate
beds in the older series.

The following causes would produce the diversity
here alluded to between the two great members of
such lacustrine formations :— When the rivers and
torrents first reach the edge of the lake, the detritus
washed down by them from the adjoining heights
sinks at once into deep water, all the heavier pebbles
and sand subsiding near the shore. The finer mud is
carried somewhat farther out, but not to the distance
of many miles, for the greater part may be seen, as, for
example, where the Rhone enters the Lake of Geneva,
to fall down in clouds to the bottom not far from the
river's mouth. ‘Thus alluvial tracts are soon formed at
the mouths of every torrentand river, and many of these
in the course of ages become of considerable extent.
Pebbles and sand are then transported farther from
the mountains ; but in their passage they decrease in
size by attrition, and are in part converted into mud
and sand. At length some of the numerous deltas

Ch. V.J IN DELTAS. 373

which are all directed towards a common centre ap-
proach near to each other — those of adjoining torrents
become united, and each is merged, in its turn, in the
delta of the largest river, which advances most rapidly
into the lake, and renders all the minor streams, one
after the other, its tributaries. The various mineral
ingredients of all are thus blended together into one
homogeneous mixture, and the sediment is poured out
from a common channel into the lake.

As the average size of the transported particles
decreases, while the force and volume of the current
augments, the newer deposits are diffused continually
over a wider area, and are consequently more horizontal
than the older. When at first there were many
independent deltas near the borders of the basin, their
separate deposits differed entirely from each other ;
one may have been charged, like the Arve where it
joins the Rhone, with white sand, and sediment de-
rived from granite — another may have been black,
like many streams in the Tyrol, flowing from the waste
of decomposing rocks of dark slate —a third may have
been coloured by ochreous sediment, like the Red

River in Louisiana—a fourth, like the Elsa in Tus-
cany, may have held much carbonate of lime in solu-
tion. At first they would each form distinct deposits
of sand, gravel, limestone, marl, or other materials ;
but after their junction new chemical combinations
and a distinct colour would be the result, and the par-
ticles, having been conveyed ten, twenty, or a greater
number of miles over alluvial plains, would become
fines.

In deltas where the causes are more complicated,
and where tides and currents partially interfere, the
above description would only be applicable, with cer-

374: CONVERGENCE OF DELTAS, [Book II.

tain modifications; but if a series of earthquakes
accompany the growth of a delta, and change the
levels of the land from time to time, as in the region
where the Indus now enters the sea, and others here-
after to be mentioned, the phenomena will then depart
still more widely from the ordinary type.

Convergence of Deltas.—If we possessed an accu-
rate series of maps of the Adriatic for many thousand
years, our retrospect would, without doubt, carry us
gradually back to the time when the number of rivers
descending from the mountains into that gulf by
independent deltas was far greater in number. The
deltas of the Po and the Adige, for instance, would
Separate themselves within the recent era, as, in all
probability, would those of the Isonzo and the Torre.
If, on the other hand, we speculate on future changes,
we may anticipate the period when the number of
deltas will greatly diminish ; for the Po cannot continue
to encroach at the rate of a mile in a hundred years,
and other rivers to gain as much in six or seven cen-
turies- upon the shallow gulf, without new junctions
occurring from time to time, so that Eridanus, “ the
king of rivers,” will continually boast a greater num-
ber of tributaries. The Ganges and the Burrampooter
have probably become confluent within the historical
era; and the date of the junction of the Red River
and the Mississippi would, in all likelihood, have been
known if America had not been so recently discovered.
The union of the Tigris and the Euphrates must un-
doubtedly have been one of the modern geographical
changes on our earth, and similar remarks might be
extended to many other regions.

When the deltas of rivers, having many mouths, con-
verge, a partial union at first takes place by the con-

Ch. V.] FORMATION OF CONGLOMERATES. 375

fluence of some one or more of their arms; but it is
not until the main trunks are connected above the head
of the common delta, that a complete intermixture of
their joint waters and sediment takes place. The
union, therefore, of the Po and Adige, and of the
Ganges and Burrampooter, is still incomplete. If we
reflect on the geographical extent of surface drained
by rivers such as now enter the Bay of Bengal, and
then consider how complete the blending together of
the greater part of their transported matter has already
become, and throughout how vast a delta it is spread
by numerous arms, we no longer feel so much surprise
at the area occupied by some ancient formations of ho-
mogeneous mineral composition. But our surprise will
be still further lessened when we afterwards inquire
into the action of tides and currents, in disseminating
sediment.*

Formation of Conglomerates. — Along the base of
the Maritime Alps, between Toulon and Genoa, the
rivers, with few exceptions, are now forming strata of
conglomerate and sand. Their channels are often
several miles in breadth, some of them being dry, and
the rest easily forded for nearly eight months in the
year, whereas during the melting of the snow they
are swollen, and a great transportation of mud and
pebbles takes place. In order to keep open the main
road from France to Italy, now carried along the sea-
coast, it is necessary to remove annually great masses
of shingle brought down during the flood-season. A.
portion of the pebbles are seen in some localities, as

near Nice, to form beds of shingle along the shore, -

but the greater part are swept into a deep sea. The

* See Chap. viii.

eair a

|
l
l

376 CAUSES OF STRATIFICATION. {Book Il.

small progress made by the deltas of minor rivers on
this coast need not surprise us, when we recollect that
there is sometimes a depth of two thousand feet at a
few hundred yards from the beach, as near Nice.
Similar observations might be made respecting a large
proportion of the rivers in Sicily, and, among others,
respecting that which, immediately north of the port
of Messina, hurries annually vast masses of granitic
pebbles into the sea.

Causes of Stratification in Deltas. —That the mat-
ter carried by rivers into seas and lakes is not thrown in
confused and promiscuous heaps, but is spread out far
and wide along the bottom, is well ascertained ; and
that it must for the most part be divided into distinct
strata, may in part be inferred where it cannot be
proved by observation. The horizontal arrangement
of the strata, when laid open to the depth of twenty or
thirty feet in the deltas of the Ganges, Indus, and
Mississippi, is alluded to by many writers; and the
same disposition is well known to obtain in all modern
deposits of lakes and estuaries.

Natural divisions are often occasioned by the interval
of time which separates annually the deposition of
matter during the periodical rains, or melting of the
snow upon the mountains. The deposit of each year
may acquire some degree of consistency before that of
the succeeding year is super imposed. A variety of cir-
cumstances alts give rise annually, or sometimes from
day to day, to slight variations in colour, fineness of
the particles, and other characters, by which alterna-
tions of strata distinct in texture, and mineral ingre-
dients, must be produced. Thus, for example, at one
period of the year, drift wood may be carried down, and
at another mud, as was before stated to be the case

ch. V.J CAUSES OF STRATIFICATION. S17

in the delta of the Mississippi; or at one time, whem
the volume and velocity of the stream are greatest,
pebbles and sand may be spread over a certain area,
over which, when the waters are low, fine matter or
chemical precipitates are formed. During inundations,
the current of fresh water often repels the sea for
many miles ; but when the river is low, salt water
again occupies the same space. When two deltas
are converging, the intermediate space is often, for
reasons before explained, alternately the receptacle
of different sediments derived from the converging
streams. The oneis, perhaps, charged with calcareous,
the other with argillaceous matter ; or one sweeps
down sand and pebbles, the other impalpable mud.
These differences may be repeated, with considerable
regularity, until a thickness of hundreds of feet of
alternating beds is accumulated. The multiplication,
also, of shells and corals in particular spots, must give
rise occasionally to lines of separation, and divide a
mass which might otherwise be homogeneous into dis-
tinct strata.

An examination of the shell marl now forming in
the Scotch lakes, or the sediment termed “ warp,”
which subsides from the muddy water of the Humber,
and other rivers, shews that recent deposits are often
composed of a great number of extremely thin layers,
either even or slightly undulating, and preserving @
general parallelism to the planes of stratification-
Sometimes, however, the laminæ in modern strata are
disposed diagonally at a considerable angle, which ap-
pears to take place where there are conflicting move-
ments in the waters. In January, 1829, I visited, in
company with Professor L. A. Necker, of Geneva, the
confluence of the Rhone and Arve, when those rivers

eee neem ec IT LIE

378 CONCLUDING REMARKS ON DELTAS, [Book II.

were very low, and were cutting channels through the
vast heaps of debris thrown down from the waters of
the Arve, in the preceding spring. One of the sand-
banks which had formed, in the spring of 1828, where
the opposing currents of the two rivers neutralized
each other, and caused a retardation in the motion,
had been undermined ; and the following is an exact
representation of the arrangement of laminz exposed
in a vertical section. The length of the portion here
seen is about twelve feet, and the height five. The
strata A A consist of irregular alternations of pebbles
and sand in undulating beds: below these are seams
of very fine sand B B, some as thin as paper, others
about a quarter of an inch thick. The strata c c are
composed of layers of fine greenish-gray sand, as thin
as paper. Some of the inclined beds will be seen to
be thicker at their upper, others at their lower ex-
tremity, the inclination of some being very consider-
able. These layers must have accumulated one on
the other by lateral apposition, probably when one of
the rivers was very gradually increasing or diminishing
in velocity, so that the point of greatest retardation

Section on the banks of the Arve at its confluence with the Rhone, showing
the stratification of deposits where currents meet.

Ch. V.] CONCLUDING REMARKS ON DELTAS. 379
caused by their conflicting currents shifted slowly,
allowing the sediment to be thrown down in succes-
sive layers on a sloping bank. The same phenome-
non js exhibited in older strata of all ages ; and when
they are treated of, I shall endeavour more fully to
illustrate the origin of such a structure.

Constant interchange of land and sea.— I may here
conclude my remarks on deltas, observing that, im-
perfect as is our information of the changes which
they have undergone within the last three thousand
years, they are sufficient to shew how constant an
interchange of sea and land is taking place on the face
of our globe. In the Mediterranean alone, many
flourishing inland towns, and a still greater number of
ports, now stand where the sea rolled its waves since
the era of the early civilization of Europe. Ifwe could
compare with equal accuracy the ancient and actual
state of all the islands and continents, we should pro-
bably discover that millions of our race are now sup-
ported by lands situated where deep seas prevailed in
earlier ages. In many districts not yet occupied by
man, land animals and forests now abound where ships
once sailed, and on the other hand, we shall find, on
inquiry, that inroads of the ocean have been no less
considerable. When to these revolutions, produced
by aqueous causes, we add analogous changes wrought
by igneous agency, we shall, perhaps, acknowledge the
justice of the conclusion of Aristotle, who declared
that the whole land and sea on our globe periodically
changed places.*

* See above, Book i. p. 22.

CHAPTER VI.

DESTROYING AND TRANSPORTING EFFECTS OF TIDES AND
CURRENTS.

Differences im the rise of the tides — Rennell’s Account of the
Lagullas and Gulf currents — Velocity of currents— Causes of
currents — Action of the sea on the British coast (p. 392.) —
Shetland Islands — Large blocks removed — Effects of light-
ning — Isles reduced to clusters of rocks — Orkney Isles —
East coast of Scotland (p- 399.) — East coast of England —
Waste of the cliffs of Holderness, Norfolk, and Suffolk —
Silting up of estuaries (p. 407.) — Origin of submarine forests
— Yarmouth estuary — Suffolk coast — Dunwich (P. 411, ) —
Essex coast — Estuary of the Thames — Goodwin Sands —
Coast of Kent — Formation of Straits of Dover (p. 420.) —
South coast of England — Sussex — Hants — Dorset —
Portland — Origin of the Chesil Bank (P. 427.) — Cornwall
— Coast of Brittany. ,

ALTHOUGH the movements of great bodies of water,
termed tides and currents, are in general due to very
distinct causes, their effects cannot be studied separ-
ately ; for they produce, by their joint action, those
changes which are objects of geological interest.
These forces may be viewed in the same manner as we
before considered rivers, first, as employed in destroy-
ing portions of the solid crust of the earth, and remov-
ing them to other places ; secondly, as reproductive of
new strata.

Tides.— It would be superfluous at the present day
to offer any remarks on the cause of the tides. They
are not perceptible in lakes, or in most inland seas ;

Ch. VL] RISE OF THE TIDES. 381

in the Mediterranean even, deep and extensive as
is that sea, they are scarcely sensible to ordinary
observation, their effects being quite subordinate to
those of the winds and currents. In some places,
however, as in the Straits of Messina, there is an
ebb and flow to the amount of two feet and upwards ;
at Naples and at the Euripus, of twelve or thirteen
inches; and at Venice, according to Rennell, of five
feet.* In the Syrtes, also, of the ancients, two wide
shallow gulfs which penetrate very far within the
northern coast of Africa, between Carthage and Cy-
rene, the rise is said to exceed five feet.t

In islands remote from any continent, the ebb and
flow of the ocean is very slight, as at St. Helena, for ex-
ample, where it is rarely above three feet.[ In any
given line of coast, the tides are greatest in narrow
channels, bays, and estuaries, and least in the interven-
ing tracts where the land is prominent. Thus, at the
entrance of the estuary of the Thames and Medway,
the rise of the spring tides is eighteen feet ; but when
we follow our eastern coast from thence northward,
towards Lowestoff and Yarmouth, we find a gradual
diminution, until, at the places last mentioned, the high-
est rise is only seven or eight feet. From this point
there begins again to be an increase, so that at Cromer,
where the coast again retires towards the west, the
rise is sixteen feet; and towards the extremity of the
guif called “the Wash,” as at Lynn and in Boston
deeps, it is from twenty-two to twenty-four feet, and
in some extraordinary cases twenty-six feet. From

* Geog. of Herod. vol. ii. p. 331. + Ibid. p. 328.
+ Romme, Vents et Courans, vol. ii. p. 2. Rev- F. Fallows,
Quart. Journ. of Science, March, 1829.

389 CURRENTS, [Book II.

thence again there is a decrease towards the north,
the elevation at the Spurn Point being from nineteen
to twenty feet, and at Flamborough Head and the
Yorkshire coast from fourteen to sixteen feet.*

At Milford Haven in Pembrokeshire, at the mouth
of the Bristol Channel, the tides rise thirty-six feet ; and
at King-Road near Bristol, forty-two feet. At Chepstow
on the Wye, a small river which opens into the estuary
of the Severn, they reach fifty feet, and sometimes
sixty-nine, and even seventy-two feet.t A current
which sets in on the French coast, to the west of Cape
La Hague, becomes pent up by Guernsey, Jersey, and
other islands, till the rise of the tide is from twenty to
forty-five feet, which last height it attains at Jerseys
and at St. Malo, a seaport of Brittany.

Currents. — The most extensive and best determined
system of currents, is that which has its source in the
Indian Ocean, under the influence of the trade winds:
and which, after doubling the Cape of Good Hope,
inclines to the northward, along the western coast of
Africa, then crosses the Atlantic, near the equator,
and is lost in the Caribbean Sea, yet seems to be again
revived in the current which issues from the gulf of
Mexico, by the straits of Bahama, and flows rapidly
in a north-easterly direction by the bank of New-
foundland, towards the Azores.

We learn from the posthumous work of Rennell on
this subject, that the Lagullas current, so called from
the cape and bank of that name, is formed by the
junction of two streams, flowing from the Indian

* The heights of these tides are given on the authority of
Captain Hewett, R. N.

f} On the authority of Captain Beaufort, R. N.

Ch, VI] CURRENTS. 383

Ocean; the one from the channel of Mozambique,
down the south-east coast of Africa; the other, from
the ocean at large. The collective stream’ is from
ninety to one hundred miles in breadth, and runs at
the rate of from two and a half to more than four
miles per hour. It is at length turned westward by
the Lagullas bank, which rises from a sea of great
depth to within one hundred fathoms of the surface.
It must, therefore, be inferred, says Rennell, that the
current here is more than one hundred fathoms deep,
otherwise the main body of it would pass across the
bank, instead of being deflected eastward, so as to
flow round the Cape of Good Hope. From this cape
it flows northward, along the western coast of Africa,
‘taking the name of the South Atlantic current.
It then enters the Bight, or Bay of Benin, and is
turned westward, partly by the form of the coast
there, and partly, perhaps, by the Guinea current,
which runs from the north into the same great bay.
From the centre of this bay proceeds the Equatorial
current, holding a westerly direction across the At-
lantic, which it traverses, from the coast of Guinea
to that of Brazil, flowing afterwards by the shores
of Guiana to the West Indies. The breadth of this
current varies from 160 to 450 geographical miles,
and its velocity is from twenty-five to. seventy-nine
miles per day, the mean rate being about thirty miles.
The length of its whole course is about 4000 miles.
As it skirts the coast of Guiana, it is increased by the
influx of the waters of the Amazon and Orinoco, and
by their junction acquires accelerated velocity. After
passing the island of Trinidad, it expands, and is
almost lost in the Caribbean Sea ; but there appears to
be a general movement of that sea towards the Mexi-

Se

rarer ener

384 CURRENTS. [Book If.

can gulf, which discharges the most powerful of all
currents through the straits of Florida, where the
waters run in the northern part with a velocity of five
miles an hour, having a breadth of from thirty-five to
fifty miles.

The temperature of the gulf of Mexico is 86°,
in summer, or 6° higher than that of the ocean,
in the same parallel (25° N. lat.), and a large pro-
portion of this warmth is retained, even where the
stream reaches the 43° N. lat. After issuing from
the straits of Florida, the current runs in a northerly
direction to Cape Hatteras, in North Carolina, about
35° N. lat., where it is more than seventy miles broad,
and still moves at the rate of seventy-five miles per day.
In about the 40° N. lat., it is turned more towards the
Atlantic by the extensive banks of Nantucket, and St.
George, which are from 200 to 300 feet beneath the
surface of the sea; a clear proof that the current ex-
ceeds that depth. On arriving near the Azores, the
stream widens, and overflows, as it were, forming a large
expanse of warm water in the centre of the North
Atlantic, over a space of 200 or 300 miles from north to
south, and having a tempature of from 8° to 10° Fahr.
above the surrounding ocean. The whole area, covered
by the gulf water, is estimated by Rennell at 2000 miles
in length, and, at a mean, 350 miles in breadth; an area
more extensive than that of the Mediterranean. The
warm water has been sometimes known to reach the
Bay of Biscay, still retaining five degrees of temper-
ature above that of the adjoining ocean, and a branch
of the gulf current occasionally drifts fruits, plants,
and wood, the produce of America, and the West
Indies, to the shores of Ireland, and the Hebrides.

From the above statements we may understand the

Ch. VL] VELOCITY OF CURRENTS. 385

description, given by Rennell, of the principal currents,
which, he says, are oceanic rivers, from 50 to 250
miles in breadth, having a rapidity exceeding that of
the largest navigable rivers of the continents, and so
deep as to be sometimes obstructed, and occasionally
turned aside, by banks which do not rise within forty
or fifty fathoms of the surface of the sea.*

Greatest Velocity of Currents. — The ordinary velo-
city of the principal currents of the ocean is from one
to three miles per hour; but when the boundary lands
converge, large bodies of water are driven gradually
into a narrower space, and then wanting lateral room
are compelled to raise their level. Whenever this
occurs, their velocity is much increased. ‘The current
which runs through the Race of Alderney, between
the island of thatname and the main land, has a velocity
of above eight English miles an hour. Captain Hewett
found that in the Pentland Firth the stream, in ordinary
spring tides, runs. ten miles and a half an hour, and
about thirteen miles during violent storms. The great-
est velocity of the tidal current through the “ Shoots,”
or New Passage, in the Bristol Channel, is fourteen
English miles an hour; and Captain King observed, in
his recent survey of the Straits of Magellan, that the
tide ran at the same rate through the “ First Narrows.”

Causes of Currents.—That movements of no incon-
siderable magnitude should be impressed on an expan-
sive ocean, by winds blowing for many months in one
direction, may easily be conceived, when we observe
the effects produced in our own seas by the temporary
action of the same cause. It is well known that a
strong south-west or north-west wind invariably raises

* Rennell on Currents, p. 58.
S

eas

386 CAUSES OF CURRENTS. [Book If

the tides to an unusual height along the east coast of
England and in the Channel; and that a north-west
wind of any continuance causes the Baltic to rise two’
feet and upwards above its ordinary level. Smeaton
ascertained by experiment that, in a canal four miles
in length, the water was kept up four inches higher
at one end than at the other, merely by the action of
the wind along the canal; and Rennell informs us that
a large piece of water, ten miles broad, and generally
only three feet deep, has, by a strong wind, had its
waters driven to one side, and sustained so as to be-
come six feet deep, while the windward side was laid
dry.*

As water, therefore, he observes, when pent up so
that it cannot escape, acquires a higher level, so, in a
place where it can escape, the same operation produces
a current ; and this current will extend to a greater or
less distance, according to the force by which it is
produced.

Currents flowing alternately in opposite directions
are also occasioned by the rise and fall of the tides.
The effect of this cause is, as before observed, most
striking in estuaries and channels between islands.

A third cause of oceanic currents is evaporation
by solar heat, of which the great current setting
through the Straits of Gibraltar into the Mediter-
ranean is a remarkable example, and will be fully
considered in the next chapter. A stream of colder
water also flows from the Black Sea into the Mediter-
ranean. It must happen in many other parts of the
world that large quantities of water raised from one
tract of the ocean by solar heat, are carried to some

* Rennell on the Channel-current.

Ch. VI] RELATIVE LEVEL OF DIFFERENT SEAS. 387

other where the vapour is condensed and falls in the
shape of rain, and this in flowing back again to restore
equilibrium, will cause sensible currents.

These considerations naturally lead to the inquiry
whether the level of contiguous seas where currents
prevail varies considerably. Arago is of opinion that,
so far as observations have hitherto been made, the
difference in relative level is not great, or at least that
it is insufficient to bear out the hypothesis that cur-
rents in general are referable to the action of prevailing
winds. He admits the important and remarkable fact
that the level of the Mediterranean near Alexandria is
lower by 26 feet 6 inches than the Red Sea near Suez
at low water, and about 30 feet lower than the Red
`- Sea at the same place at high water. This result was

obtained during the French expedition to Egypt, from
the measurements of M. Lepére.*

It was formerly imagined that there was an equal, if
not greater diversity, in the relative levels of the
Atlantic and Pacific, on the opposite sides: of the
isthmus of Panama. But the levellings recently car-
ried across that isthmus by Mr. Lloyd, to ascertain
the relative height of the Pacific Ocean at Panama,
and of the Atlantic at the mouth of the river Chagres,
have shown, that the difference of mean level between
those oceans. is not considerable, and contrary to ex-
pectation the difference which does exist is in favour
of the greater height of the Pacific. According to the
result of this survey, on which great dependence may
be placed, the mean height of the Pacific is three feet
and ahalf, or 3.52 above the Atlantic, if we assume
the mean level of a sea to coincide with the mean
between the extremes of the elevation and depression

_ * An. du Bureau des Long. pour Tan 1836.
s@2

388 CAUSES OF CURRENTS. [Book IT.

of the tides ; for between the extreme levels of the
greatest tides in the Pacific, at Panama, there is a
difference of 27.44 feet; and at the usual spring tides
21.22 feet : whereas at Chagres this difference is only
1.16 feet, and is the same at all seasons of the year.
The tides, in short, in the Caribbean Sea are
scarcely perceptible, not equalling those in some parts
of the Mediterranean, whereas the rise is very high in
the Bay of Panama ; so that the Pacific is at high tide
lifted up several feet above the surface of the Gulf of
Mexico, and then at low water let down as far below
it.* But astronomers are agreed that, on mathemati-
cal principles, the rise of the tidal wave above the mean
level of a particular sea must be greater than the fall
below it ; and although the difference has been hitherto
supposed insufficient to cause an appreciable error, it
is, nevertheless, worthy of observation, that the error,
such as it may be, would tend to reduce the small
difference, now inferred, from the observations of Mr.
Lloyd, to exist between the levels of the two oceans.
There is still another way in which heat and cold
must occasion great movements in the ocean, a cause
to which, perhaps, currents are principally due. It is
now ascertained that there is in sea water no point as
in fresh water, at which an increase of cold causes the
fluid tobegin again to expand. In the ocean, therefore,
whenever the temperature of the surface is lowered,
condensation takes place, and the superficial water,
having its specific gravity increased, falls to the bottom,
upon which lighter water rises immediately and oc-
cupies its place. When this circulation of ascending
and descending currents has gone on for a certain time
in high latitudes, the inferior parts of the sea are made

* Phil. Trans;, 1830, p- 59.

Ch. VEJ CAUSES OF CURRENTS. 389

to consist of colder or heavier fluid than the corre-
sponding depths of the ocean between the tropics. If
there be a free communication, if no chain of submarine
mountains divide the polar from the equatorial basins,
a horizontal movement will arise by the flowing of
colder water from the poles to the equator, and there
will then be a reflux of warmer superficial water from
the equator to the poles. A well-known experiment
has been adduced to elucidate this mode of action in
explanation of the “trade winds.’* If along trough,
divided in the middle by a sluice or partition, have one
end filled with water and the other with quicksilver,
both fluids will remain quiet solong as they are divided ;
but when the sluice is drawn up, the heavier fluid will
rush along the bottom of the trough, while the lighter,
being displaced, will rise, and, flowing in an opposite
direction, spread itself at the top. In like manner the
expansion and contraction of sea-water by heat and
cold have a tendency to set under-currents in motion
from the poles to the equator, and to cause counter-
currents at the surface which are impelled in a direction
contrary to that of the prevailing trade winds. The
geographical and other circumstances being very com-
plicated, we cannot expect to trace separately the move-
ments due to each cause, but must be prepared for
many anomalies, especially as the configuration of the
bed of the ocean must often modify and interfere with
the course of the inferior currents, as much as the
position and form of continents and islands are found
to alter the direction of those on the surface.

Each of the four causes above mentioned, the wind,

* See Capt. B. Hall’s clear Explanation of the Theory of the
Trade Winds, Fragmentsof Voyages, second series, vol. i., and his
letter in the Appendix to Daniell’s Meteorology.

s 3

390 CAUSES OF CURRENTS. [Book HH.

the tides, evaporation, and the expansion and contrac-
tion of water by heat and cold, may be conceived to
operate independently of the others, and although the
influence of all the rest were annihilated. But there
is another Cause, the rotation of the earth on its axis,
which can only come into play when the waters have
already been set in motion by some one or all of the
forces above described, and when the direction of the
current so raised happens to be from south to north, or
from north to south.*

The principle on which this cause operates is pro-
bably familiar to the reader, as it has long been
recognized in the case of the trade winds. Without
enlarging, therefore, on the theory, it will be sufficient
to offer an example of the mode of action alluded to.
When a current flows from the Cape of Good Hope
towards the Gulf of Guinea, it consists of a mass: of
water, which, on doubling the Cape, in lat. 35°, has a
rotatory velocity of about 800 miles an hour ; but
when it reaches the line, it arrives at a parallel where
the surface of the earth is whirled round at the rate
of 1000 miles an hour, or about 200 miles faster. If
this great mass of water was transferred suddenly

* In an interesting essay in the United Service Journal (Dec.
1833), an attempt is made to introduce the earth’s rotation as a
primary cause of currents. But the author appears to misconceive
the ‘mode in which alone: this rotation could produce any effect,
and reasons as if it would in all latitudes cause currents from east
to west. He also seems never to have heard of Mr. Lloyd’s level-
lings across the Isthmus of Panama, by which the waters of the
Gulf of Mexico are proved (if there be any difference) to be lower
than the mean level of the Pacific. He also assumes erroneously
that the quantity of rain is greatly in excess in high instead of low
latitudes.

t See a table in Capt. Hall’s work before cited.

a a e E

\

Ch. VLI CAUSES OF CURRENTS. 391

from the higher to the lower latitude, the deficiency
of its rotatory motion, relatively to the land and water
with which it would come into juxtaposition, would be
such as to cause an apparent motion of the most rapid
kind (of no less than 200 miles an hour) from east to
west.

In the case of such a sudden transfer, the eastern
coast of America, being carried round in. an opposite
direction, might strike against a large body of water with
tremendous violence, and aconsiderable part of the con-
tinent might be submerged. This disturbance does not
occur, because the water of the stream, as it advances
gradually into new zones of the sea which are moving
more rapidly, acquires by friction an accelerated ve-
locity. Yet as this motion is not imparted instant-
aneously, the fluid is unable to keep up with the full
speed of the new surface over which it is successively
‘brought. Hence, to borrow the language of Herschel,
when he speaks of the trade winds, “ it lags or hangs
back, in a direction opposite to the earth’s rotation,
that is, from east to west,” * and thus a current which
would have run simply towards the north but for the
rotation, may acquire a relative direction towards the
west, or become a gouth-easterly current.

We may next consider a case where the circum-
stances are the converse of the above. The Gulf
stream flowing from about lat. 20°, is at first impressed
with a velocity of-rotation of about 940 miles an hour,
and runs to the lat. 40°, where the earth revolves only
at the rate of 766 miles, or 174 miles slower. In this
case a relative motion of an opposite kind. may result ;
and the current may retain an excess of rotatory
velocity, tending continually to deflect it eastward.

* Treatise on Astronomy, chap. 3.

s 4

392 ACTION OF THE SEA ON [Book II.

‘Thus it will be seen that currents depend like the
tides on no temporary or accidental circumstances,
but on the laws which preside over the motions of the
heavenly bodies. But although the sum of their in-
fluence in altering the surface of the earth may be
very constant throughout successive epochs, yet the
points where these operations are displayed in fullest
energy shift perpetually. The height to which the
tides rise, and the violence and velocity of currents,
depend in a great measure on the actual configuration
of the land, the contour of a long line of continental or
insular coast, the depth and breadth of channels, the
peculiar form of the bottom of seas—in a word, on
a combination of circumstances which are made to
vary continually by many igneous and aqueous causes,
and, among the rest, by the tides and currents them-
selves. Although these agents, therefore, of decay
and reproduction are local in reference to periods of
short duration, such as those which history embraces,
they are nevertheless universal, if we extend our views
to a sufficient lapse of ages.

Action of the Sea on the British Coasts.— If we follow
the eastern and southern shores of the British islands,
from our Ultima Thule in Shetland to the Land’s End
in Cornwall, we shall find evidence of a series of
changes since the historical era, very illustrative of
the kind and degree of force exerted by tides and
currents, co-operating with the waves of the sea. In
this survey we shall have an Opportunity of tracing
their joint power on islands, promontories, bays, and
estuaries ; on bold, lofty cliffs, as well as on low shores ;
and on every description of rock and soil, from granite
to blown sand.

Shetland Islands.— The northernmost group of the

Ch. VLJ THE SHETLAND ISLANDS. 393

British islands, the Shetland, are composed of a great
variety of rocks, including granite, gneiss, mica-slate,
serpentine, greenstone, and many others, with some
secondary rocks, chiefly sandstone and conglomerate.
‘These islands are exposed continually to the uncon-
trolled violence of the Atlantic, for no land intervenes
between their western shores and America. The pre-
valence, therefore, of strong westerly gales causes the
waves to be sometimes driven with irresistible force
upon the coast, while there is also a current setting
from the north. The spray of the sea aids the decom-
position of the rocks, and prepares them to be breached
by the mechanical force of the waves. Steep cliffs are
hollowed out into deep caves and lofty arches ; and
almost every promontory ends in a cluster of rocks,
imitating the forms of columns, pinnacles, and obelisks.

Drifting of large Masses of Rock.— Modern observ-
ations show that the reduction of continuous tracts to
such insular masses is a process in which Nature is
still actively engaged. “ The Isle of Stenness,” says
Dr. Hibbert, “presents a scene of unequalled desola-
tion. In stormy winters, huge blocks of stones are
overturned or are removed from their native beds, and
hurried up a slight acclivity to a distance almost in-
credible. In the winter of 1802, a tabular-shaped
mass, eight feet two inches by seven feet, and five
feet one inch thick, was dislodged from its bed, and
removed to a distance of from eighty to ninety feet. I
measured the recent bed from which a block had been
carried away the preceding winter (A. D. 1818), and
found it to be seventeen feet and a half by seven feet,
and the depth two feet eight inches. ‘The removed
mass had been borne to a distance of thirty feet, when
it was shivered into thirteen or more lesser fragments,

s ‘5

394 EFFECTS OF LIGHTNING. [Book II.

some of which were carried still farther, from 30 to
120 feet. A block, nine feet two inches by six feet
and a half, and four feet thick, was hurried up the
acclivity to a distance of 150 feet.” *

At Northmavine, also, angular blocks of stone have
been removed in a similar manner to considerable dis-
tances by the waves of the sea, some of which are re-
presented in the annexed figure.+ A

Stony fragments drifted by the sea. Northmavine, Shetland.

Effects of Lightning.—In addition to numerous
examples of masses detached and driven by the waves,
tides, and currents from their place, some remarkable
effects of lightning are recorded in these isles. - At
Funzie, in Fetlar, about the middle of the last century,
a rock of mica-schist, 105 feet long, ten feet broad, and
in some places four feet thick, was in an instant torn
by a flash of lightning from its-bed, and broken into
three large, and several smaller, fragments. One of

* Descrip. of Shetland Islands, p.527. Edin, 1822.

+ For this and the three following representations of rocks in
the Shetland Isles, I am indebted to Dr. Hibbert’s work before
cited, which is rich in antiquarian and geological research,

Ch. VLI SHETLAND ISLANDS. 395

these, twenty-six feet long, ten feet broad, and four
feet thick, was simply turned over. The second, which
was twenty-eight feet long, seventeen broad, and five
feet in thickness, was hurled across a high point to the
distance of. fifty yards. Another broken mass, about
forty feet long, was thrown still farther, but in the
same direction, quite into the:sea. There were also’
many smaller fragments scattered up and down.*

When we thus see electricity co-operating with. the
violent movements of the ocean in heaping up piles_of
shattered rocks on dry land, and beneath the waters,
we cannot but admit that a region which shall be the
theatre, for myriads of ages, of the action of such dis-
turbing causes, might present, at some future period,
if upraised far above the bosom of the deep,.a scene of
havoc and ruin that may compare with any now found
by the geologist on the surface of our continents. _

In some of the Shetland Isles, as on the west of
Meikle Roe, dikes, or veins of soft granite, have
mouldered away ; while the matrix in which they were
inclosed, being of the same substance, but of a firmer
texture, has remained unaltered. Thus, long. narrow
ravines, sometimes twenty-feet wide, are laid open, and
often give access to the waves. - After describing some
huge cavernous apertures into which the sea flows for
250 feet in Roeness, Dr. Hibbert enumerates other
ravages of the ocean. ‘“ A mass of rock, the average
dimensions of which may perhaps be rated at twelve or
thirteen feet square, and four and a half or five in thick-
ness, was first moved from its bed, about fifty years
ago, to a distance of thirty feet, and has‘since been
twice turned over.”

* Dr. Hibbert, from MSS. of Rev. George Low, of Fetlar.
s 6

396 ACTION OF THE SEA. ON [Book II.

Passage forced by the sea through pPorphyritie rocks. —
“ But the most sublime scene is where a mural pile of
porphyry, escaping the process of disintegration that
is devastating the coast, appears to have been left as a
sort of rampart against the inroads of the ocean ;—the
Atlantic, when provoked by wintry gales, batters
against it with all the force of real artillery —the
waves having, in their repeated assaults, forced them-
selves an entrance. This breach, named the Grind of
the Navir (Fig. 15.), is widened every winter by the
overwhelming surge that, finding a passage through it,

Grind of the Navir — Passage forced by the sea through rocks of hard
porphyry.

separates large stones from its sides, and forces them
to a distance of no less than 180 feet. In two or three
spots, the fragments which have been detached are
brought together in immense heaps, that appear as an

Ch. VLJ THE SHETLAND ISLANDS.- 397

accumulation of cubical masses, the product of some
quarry.” *

It is evident, from this example, that although the
greater indestructibility of some rocks may enable
them to withstand, for a longer time, the action of the
elements, yet they cannot permanently resist. There
are localities in Shetland, in which rocks of almost
every variety of mineral composition are suffering dis-
integration; thus the sea makes great inroads on the
clay slate of Fitfel Head, on the serpentine of the
Vord Hill in Fetlar, and on the mica-schist of the
Bay of Triesta, on the east coast of the same island,
which decomposes into angular blocks. The quartz
rock on the east of Walls, and the gneiss and mica-
schist of Garthness, suffer the same fate.

Destruction of Islands.— Such devastation cannot
be incessantly committed for thousands of years with-
out dividing islands, until they become at last mere

Fig. 16.

Granitic rocks named the Drongs, between Papa Stour and
Hillswick Ness. a

* Hibbert, p. 528.

ENCROACHMENTS OF THE SEA ON [Book H.

clusters of ‘rocks, the last shreds of masses once con-
tinuous. To this state many appear to have. been
reduced, and innumerable fantastic forms are assumed
by rocks adjoining these islands, to which the name of
Drongs is applied, as it is to those of similar shape in
Feroe.

The granitic rocks (Fig. 16.) between Papa Stour
and Hillswick Ness afford an example. A. still more
singular cluster of rocks is seen to the south of Hills-
wick Ness (Fig..17.) which presents a variety: of forms
as viewed from different points, and has often been
likened to -a small fleet of vessels with spread . sails. *

. We may imagine that in the course of time Hillswick

Fig. 17

Granitic rocks to the south of Hillswick Ness, Shetiand.

Ness itself may present a similar wreck, from the un-
equal decomposition of the rocks whereof it is com-
posed, consisting of gneiss and mica-schist, traversed
in all directions by veins of felspar porphyry.

* Hibbert, p. 519.

Ch. VIJ THE EAST COAST OF SCOTLAND. 399

Midway between the groups of Shetland and Orkney
is Fair Island, said to be composed of sandstone with
high perpendicular cliffs. The current runs with such
velocity, that during a calm, and when there is no
swell, the rocks on its shores are white with the foam
of the sea driven against them. The Orkneys, if
carefully examined, would probably illustrate our pre-
sent topic as much as the Shetland group. The north-
east promontory of Sanda, one of these islands, has
been cut off in modern times by the sea, so that it »
became what is now called Start Island, where a light-
house was erected in 1807, since which time the new
strait has grown broader.

East coast of Scotland.—To pass over to the main
land of Scotland, we find that, in Inverness-shire, there
have been inroads of the sea at Fort George, and
others in Morayshire, which have swept away the old
town of Findhorn. On the coast of Kincardineshire,
an illustration was afforded, at the close of the Jast cen-
tury, of the effect of promontories in protecting a line
of low-shore. The village of Mathers, two miles south
of Johnshaven, was built on an ancient shingle beach,
protected bya projecting ledge of limestone rock. This
was quarried for lime to such an extent, that the sea
broke through, and in 1795 carried away the whole
village in one night, and penetrated 150 yards inland,
where it has maintained its ground ever since, the new
village having been built farther inland on the new
shore. In the Bay of Montrose, we find the North
Esk and the South Esk rivers pouring annually into
the sea large quantities of sand and pebbles, yet they
have formed no deltas ; for the tides scour out the
channels ; and the current, setting across their mouths,
sweeps away all the materials. .Considerable beds of

400 ENCROACHMENTS OF THE SEA ON ` [Book II.

shingle, brought down by the North Esk, are seen
along the beach.

Proceeding southwards, we find that at Arbroath, in
Forfarshire, which stands on a rock of red sandstone,
gardens and houses have been carried away within the
last thirty years by encroachments of the sea. It has
become necessary to remove the lighthouses at the
mouth of the estuary of the Tay, in the same county,
at Button Ness, which were built on a tract of blown
sand, the sea having encroached for three quarters of
a mile.

Force of Waves and Currents: in Estuaries.—The
combined power which waves and currents can exert
in estuaries to considerable depths, was remarkably ex-
hibited during the building of the Bell Rock Lighthouse,
off the mouth of the Tay. The Bell Rock is a sunken
reef, consisting of red sandstone, being from twelve to
sixteen feet under the surface at high water, and about
twelve miles from the mainland. At the distance of
100 yards, there is a depth, in all directions, of two ur
three fathoms at low water. In 1807, during the
erection of the lighthouse, six large blocks of. granite,
which had been landed on the reef, were removed by
the force of the sea, and thrown over a rising ledge to
the distance of twelve or fifteen paces; and an anchor,
weighing about 22 cwt., was thrown up upon the rock.*
Mr. Stevenson informs us, moreover, that drift stones,
measuring upwards of thirty cubic feet, or more than
two tons weight, have, during storms, been often
thrown upon the rock from the deep water. +

Submarine forests. — Among the proofs that the sea
has encroached both on the estuaries of the Tay and

* Account of the Erection of the Bell Rock Lighthouse, p. 163.
t Ed. Phil. Journ. vol. iii. p. 54. 1820.

Ch. VLJ THE EAST COAST OF SCOTLAND. 4.01

Forth, may be mentioned the submarine forests which
have been traced for several miles by Dr. Fleming;
along the margins of those estuaries on the north and
south shores of the county of Fife.* The alluvial
tracts, however, oD which such forests grow, generally
occupy spaces which may be said to be in dispute
between the river and the sea, and to be alternately
lost and won. Estuaries (a term which we confine to
inlets entered both by rivers and tides of the sea)
have a tendency to become silted up in parts ; but the
same tracts, after remaining dry, perhaps, for thousands
of years, are again liable to be overflowed, for they
are always low, and, if inhabited, must generally be
secured by artificial embankments. Meanwhile the
sea devours, as it advances, the high as well as the
low parts of the coast, breaking down, one after
another, the rocky bulwarks which protect the mouths
of estuaries. The changes of territory, therefore,
within the general line of coast are all of a subordi-
nate nature, in no way tending to arrest the march of
the great ocean, nor to avert the destiny eventually
awaiting the whole region ; they are like the petty
wars and conquests of the independent states and
republics of Greece, while the power of Macedon
was steadily pressing on, and preparing to swallow up
the whole. -

On the coast of Fife, at St. Andrew's, a tract of
land which intervened between the castle of Cardinal
Beaton and the sea, has been entirely swept away, aS
were the last remains of the Priory of Crail, in the
same county, in 1803. On both sides of the Frith of
Forth, land has been consumed; at North Berwick in

* Quart. Journ. of Sci., &c., No. xu. N. S. March, 1830.

4.02 ENCROACHMENTS OF THE SEA. ON [Book H.

particular, and at Newhaven, where an arsenal and
dock, built in the reign of James IV., in the fifteenth
century, has been overflowed.

East coast of England.—I€ we now proceed to the
English coast, we find records of numerous lands
having been destroyed in Northumberland, as those
near Bamborough and Holy Island, and at Tynemouth
Castle, which now overhangs the sea, although formerly
separated from it by a strip of land. At Hartlepool,
and several other parts of the coast of Durham com-
posed of magnesian limestone, the sea has made con-
siderable inroads. l

Coast of Yorkshire.— Almost the whole coast -of
Yorkshire, from the mouth of the Tees to that of the
Humber, is in a state of. gradual dilapidation. That
part of the cliffs which consists of lias, the oolite series,
and chalk, decays slowly. They present abrupt and
naked precipices, often 300 feet in height ; and it is
only at a few. points that the grassy covering of the
sloping talus marks a temporary relaxation of the
erosive action of the sea. The chalk cliffs are washed
into caves in the projecting headland of Flamborough,
where they are decomposed by the salt spray, and
slowly crumble away. But the waste is most rapid
between that promontory and Spurn Point, or the
coast of Holderness, as it is called, a tract consisting
of beds of clay,.gravel, sand,-and chalk rubble. The
irregular intermixture of the argillaceous beds. causes
many springs to be thrown out, and this facilitates the
undermining process, the waves beating against them,
and.a strong current setting chiefly from the north.
The wasteful action is very conspicuous at Dimlington
Height, the loftiest point in Holderness, where the
beacon stands on a cliff 146 feet above high water, the

Ch. VL] THE EAST COAST OF ENGLAND. 403

whole being composed of clay, with pebbles scattered
through it.* :
In the old maps of Yorkshire, we find spots, now
sand-banks in the sea, marked as the ancient sites of
the towns and villages of Auburn, Hartburn, and
Hyde. “ Of Hyde,” says Pennant, “ only the tradi-
tion is left; and near the village of Hornsea, a street
called Hornsea Beck has long since been swallowed.” +
Owthorne and its church have also been in great part
destroyed, and the village of Kilnsea ; but these places
are now removed farther inland. The rate of encroach-
ment at Owthorne, at present, is about four yards a
year. Not unreasonable fears are entertained that
at some future time the Spurn Point will become an
island, and that the ocean, entering into the estuary
of the Humber, will cause great devastation.§ Pen-
nant, after speaking of the silting up of some ancient
ports in that estuary, observes, “ But, in return, the
sea has made most ample reprisals ; the site, and even
the very names of several places, once towns of note
upon the Humber, are now only recorded in history ;
and Ravensper was at one time a rival to Hull (Madox,
Ant. Exch. i. 422.), and a port s0 very considerable in
1332, that Edward Baliol and the confederated En-
glish Barons sailed from hence to invade Scotland ; and
Henry IV., in 1399, made choice of this port to land
at, to effect the deposal of Richard II. ; yet the whole
of this has long since been devoured by the merciless

* Phillips's Geology of Yorkshire, p. 61.

T Arctic Zoology: vol. i. p. 10. Introduction.

ł For this information I am indebted ‘to Mr. Phillips, of
York.
GS Phillip’s Geology of Yorkshire, p: 60-

404 ENCROACHMENTS OF THE SEA ON [Book II.

ocean: extensive sands, dry at low water, are to be
seen in their stead. ” *

Pennant describes Spurn Head as a promontory in
the form of a sickle, and says the land, for some miles
to the north, was « perpetually preyed on by the fury
of the German Sea, which devours whole acres at a
time, and exposes on the shores considerable quantities
of beautiful amber. i

According to Bergmann, a strip of land, with several
villages, was carried away near the mouth of the
Humber in 1475.

Lincolnshire.—The maritime district of Lincoln-
shire consists chiefly of lands that lie below the level
of the sea, being protected by embankments. Great
parts of this fenny tract were, at some unknown period,
a woody country, but were afterwards inundated, and
are now again recovered from the sea. Some of the
fens were embanked and drained by the Romans ; but
after their departure the sea returned, and large tracts
were covered with beds of silt containing marine
shells, now again converted into productive lands.
Many dreadful catastrophes are recorded by incursions
of the sea, whereby several parishes have been at dif-
ferent times overwhelmed. `

Norfolk.— We come next to the cliffs of Norfolk
and Suffolk, where the decay is in general incessant
and rapid. At Hunstanton, on the north, the under-
mining of the lower arenaceous beds at the foot of the
cliff causes masses of red and white chalk to be pre-
cipitated from above. Between Hunstanton and Wey-
‘bourne, low hills, or dunes, of blown sand, are formed
along the shore, from fifty to sixty feet high. They

* Arct. Zool. vol. i. P. 13. Introduction. + Ibid.

Ch. VIJ THE EAST COAST OF ENGLAND. 405

are composed of dry sand, bound in a compact mass
by the long creeping roots of the plant called Marram
(Arundo arenaria). Such is the present set of the
tides, that the harbours of Clay, Wells, and other
places, are securely defended by these barriers; afford-
ing a clear proof that it is not the strength of the
material at particular points that determines whether
the sea shall be progressive or stationary, but the
general contour of the coast.

The waves constantly undermine the low chalk
cliffs, covered with sand and clay, between Weybourne
and Sherringham, a certain portion of them being
annually removed. At the latter town I ascertained,
in 1829, some facts which throw light on the rate at
which the sea gains upon the land. It was computed,
when the present inn was built, in 1805, that it would
require seventy years for the sea to reach the spot:
the mean loss of land being calculated, from previous
observations, to be somewhat less than one yard an-
nually. The distance between the house and the sea
was fifty yards ; but no allowance was made for the
slope of the ground being from the sea, in consequence
of which, the waste was naturally accelerated every
year, as the cliff grew lower, there being at each suc-
ceeding period less matter to remove when portions
of equal area fell down. Between the years 1824 and
1829, no less than seventeen yards were swept away,
and only a small garden was then left between the
building and the sea. There is now a depth of twenty
feet (sufficient to float a frigate) at one point in the
harbour of that port, where, only forty-eight years
ago, there stood a cliff fifty feet high, with houses
upon it! If once in half a century an equal amount
of change were produced suddenly by the momentary

406 ENCROACHMENTS OF THE SEA. [Book II.

shock of an earthquake, history would be filled with
records of such wonderful revolutions of the earth’s
surface; but, if the conversion of high land into deep
sea be gradual, it excites only local attention. The
flag-staff of the Preventive Service station, on the
south side of this harbour, has, within the last fifteen
years, been thrice removed inland, in consequence of
the advance of the sea.

Farther to the south we find cliffs, composed, like
those of Holderness before mentioned, of alternating
strata of blue clay, gravel, loam, and fine sand. Al-
though they sometimes exceed 200 feet in height,
the havoc made on the coast is most formidable. The
whole site of ancient Cromer now forms part of the
German Ocean, the inhabitants having gradually re-
treated inland to their present situation, from whence
the sea still threatens to dislodge them. In the winter
of 1825, a fallen mass was precipitated from near the
lighthouse, which covered twelve acres, extending far
into the sea, the cliffs being 250 feet in height.*
The undermining by springs has sometimes caused
large portions of the upper part of the cliffs, with
houses still standing upon them, to give way, so that
it is impossible, by erecting breakwaters at the base of
the cliffs, permanently to ward off the danger.

On the same coast, the ancient villages of Shipden,
Wimpwell, and Eccles, have disappeared ; several
manors and large portions of neighbouring parishes
having, piece after piece, been swallowed up; nor has
there been any intermission, from time immemorial,
in the ravages of the sea along a line of coast twenty
miles in length, in which these places stood.t Hills

* Taylor’s Geology of East Norfolk, p. 22. + Ibid.

Ch. VI] SILTING UP OF ESTUARIES. 407

of blown sand, between Eccles and Winterton, have
‘barred up and excluded the tide for many hundred
years from the mouths of several small estuaries; but
there are records of nine breaches from 20 to 120
yards wide, having been made through these, by which
immense damage was done to the low grounds in the
interior. A few miles south of Happisburgh, also, are
hills of blown sand, which extend to Yarmouth; and
these are supposed to protect the coast, but in fact
their formation proves that a temporary respite of the
incursions of the sea on this part is permitted by the
present set of the tides and currents. Were it other-
wise, the land, as we have seen, would give way,
though made of solid rock.

Silting up of Estuaries. — At Yarmouth, the sea has
not advanced upon the sands in the slightest degree
since the reign of Elizabeth. In the time of the
Saxons, a great estuary extended as far as Norwich,
which city is represented, even in the thirteenth and
fourteenth centuries, as « situated on the banks of an
arm of the sea.” The sands whereon Yarmouth is built
first became firm and habitable ground about the year
1008, from which time a line of dunes has gradually
increased in height and breadth, stretching across the
whole entrance of the ancient estuary, and obstructing
the ingress.of the tides so completely, that they are
only admitted by the narrow passage which the river
keeps open, and which has gradually shifted several
miles to the south. The ordinary tides at the river's
mouth rise, at present, only to the height of three or
four feet, the spring tides to about eight or nine.

By the exclusion of the sea thousands of acres in
the interior have become cultivated lands ; and, ex-
clusive of smaller pools, upwards of sixty fresh-water’

408 SILTING UP OF ESTUARIES. [Book II.

lakes have been formed, varying in depth from fifteen
to thirty feet, and in extent from one acre to twelve
hundred.* The Yare, and other rivers, frequently
communicate with these sheets of water; and thus
they are liable to be filled up gradually with lacustrine
and fluviatile deposits, and to be converted into land
covered with forests. When the sea at length returns
(for as the whole coast gives way, this must inevitably
happen sooner or later), these tracts will be again sub-
merged, and submarine forests may then be found, as
along the margins of many estuaries.

Yarmouth does not project beyond the general line
of coast which has been rounded off by the predomi-
nating current from the north-west. It must not be
imagined, therefore, that the acquisition of new land
fit for cultivation in Norfolk and Suffolk indicates any
permanent growth of the eastern limits of our island,
to compensate its reiterated losses. No delta can
form on such a shore.

That great banks should be thrown across the es-
tuary of the Yare, or any other estuary on our eastern
coast, where there is not a large body of river-water to
maintain an open channel, is perfectly intelligible, when
we bear in mind that the marine current, sweeping
along the coast, is charged with the materials of wast-
ing cliffs, and ready to form a bar anywhere, the instant
its course is interrupted or checked by any opposing
stream. The mouth of the Yare has been, within the
last five centuries, diverted about four miles to the
south; so it is evident that at some remote period the
river Alde entered the sea at Aldborough, until its

* Taylor’s Geology of East Norfolk, p. 10.

+ For remarks on the origin of Submarine Forests, see Book
III. chap. 16.

Ch. VL] ENCROACHMENTS OF THE SEA. 409

ancient outlet was barred up and at length transferred
to a point no less than ten miles distant to the south-
west. In this case ridges of sand and shingle like
those of Lowestoff Ness, which will be described by-
and-by, have been thrown up between the river and
the sea; and an ancient sea-cliff is to be seen, now

inland.

It may be asked why the rivers on our east coast
are always deflected southwards, although the tidal
current fiows alternately from the south and north ?
The cause is to be found in the superior force of what

commonly called “ the flood tide from the north,” a
tidal wave derived from the Atlantic, a small part of
which passes eastward up the English Channel, and
through the Straits of Dover and then northwards,
while the principal body of water, moving much more
rapidly in a more open sea, first passes the Orkneys,
and then turning flows down between Norway and
Scotland, and sweeps with great velocity along our
eastern coast. It is well known that the highest tides
on this coast are occasioned by a powerful north-west
wind which raises the eastern part of the Atlantic, and
causes it to pour a greater volume of water into the
German ocean. This circumstance of a violent off-
shore wind being attended with a rise of the waters,
instead of a general retreat of the sea, naturally ex-
cites the wonder of the inhabitants of our coast. In
many districts they look with confidence for a rich
harvest of that valuable manure, the sea-weed, when
the north-westerly gales prevail, and are rarely disap-
pointed. The phenomenon is so well calculated to
awaken curiosity, that I have heard the cause discussed
by peasants and fishermen ; and more than once they —
have hazarded a theory of their own to account for it.

VOL. I. > yi

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410 “ _ENCROACHMENTS OF THE SEA [Bock I}.

The most ingenious idea which I heard suggested was
this: a vast body of surface water, say they, is repelled
by the wind from the shore, which afterwards returns,
in order to restore the level of the sea; by this means
a strong under-current is produced, which tears up the
weed from the bed of the sea, and casts itashore. The
true explanation, however, of the phenomenon is
doubtless that above mentioned.

Coast of Suffolk. — The cliffs of Suffolk, to which
we next proceed, are somewhat less elevated than those
of Norfolk, but composed of similar alternations of clay,
sand, and gravel. From Gorleston in Suffolk, to within
a few miles north of Lowestoff, the cliffs are slowly
undermined. Near the last-mentioned town, there is
an inland cliff about sixty feet high, the sloping talus
of which is covered with turf and heath. Between the
cliff and the sea is a low, flat tract of sand, called the
Ness, nearly three miles long, and for the most part

Map of Lowestoff Ness, Suffolk. *
a,c. The dotted lines express a series of ridges of sand and
shingle, forming the extremity of the triangular space called the

Ness.

b, b,b. The dark line represents the inland cliff on which the
town of Lowestoff stands, between which and the sea is the
Ness.

* From Mr. R. C. Taylor’s Mem., see below.

Ch. VL] ON THE SUFFOLK COAST. ALY

out of reach of the highest tides. The point of the
Ness projects from the base of the original cliff to the
distance of 660 yards. This accession of land, says
Mr. Taylor, has been effected at distinct and distant
intervals, by the influence of currents running between
the land and a shoal about a mile off Lowestoff, called
the Holm Sand. The lines of growth in the Ness are
indicated by a series of concentric ridges or embank-
ments inclosing limited areas, and several of these
ridges have been formed within the observation of per-
sons now living. A rampart of heavy materials is first
thrown up to an unusual altitude by some extraordinary
tide, attended with a violent gale. Subsequent tides
extend the base of this high bank of shingle, and the
interstices are then filled with sand blown from the
beach. The Arundo and other marine plants by de-
grees obtain a footing ; and creeping along the ridge,

give solidity to the mass, and form in some cases a

matted covering of turf. Meanwhile another mound
is forming externally, which by the like process rises
and gives protection to the first. If the sea forces its
way through one of the external and incomplete
mounds, the breach is soon repaired. After a while
the marine plants within the areas inclosed by these
embankments are succeeded by a better species of
herbage, affording good pasturage, and the sands be-
come sufficiently firm to support buildings.*
Destruction of Dunwich by the Sea.— The sea under-
mines the high cliffs near Corton, a few miles north of
Lowestoff, as also two miles south of the same town,
at Pakefield, a village which has been in part swept

* The formation of the Ness is well described by Mr. Ray:
Taylor, Phil. Mag. Oct. 1527. p. 297. -
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412 ENCROACHMENTS OF THE SEA ON [Book Il.

away during the present century. From thence to
Dunwich the destruction is constant. At the distance
of 250 yards from the wasting cliff at Pakefield, where
we must suppose land to have existed at no remote
period, the sea is sixteen feet deep at low water, and
in the roadstead beyond, twenty-four feet. Of the
gradual destruction of Dunwich, once the most consi-
derable seaport on this coast, we have many authentic
records. Gardner in his history of that borough, pub-
lished in 1754, shows, by reference to documents
beginning with Doomsday Book, that the cliffs at
Dunwich, Southwold, Eastern, and Pakefield, have
been always subject to wear away. At Dunwich, in
particular, two tracts of land which had been taxed in
the eleventh century, in the time of King Edward the
Confessor, are mentioned, in the Conqueror’s survey,
made but a few years afterwards, as having been de-
voured by the sea. The losses, at a subsequent period,
of a monastery,—at another of several churches, —
afterwards of the old port,—then of four hundred
houses at once,—of the church of St. Leonard, the
high road, town-hall, gaol, and many other buildings,
are mentioned, with the dates when they perished. It
is stated that, in the sixteenth century, not one quar-
ter of the town was left standing ; yet the inhabitants
retreating inland, the name was preserved, as has been
the case with many other ports, when their ancient site
has been blotted out. There is, however, a church,
of considerable antiquity, still standing, the last of
twelve mentioned in some records. In 1740, the laying
open of the churchyard of St. Nicholas and St. Francis,
in the sea-cliffs, is well described by Gardner, with
the coffins and skeletons exposed to view— some lying
on the beach, and rocked—

Ch. VI.) _ THE EAST COAST OF ENGLAND.

« In cradle of the rude imperious surge.”

Of these cemeteries no remains can now be seen.
Ray also says, « that ancient writings make mention
of a wood a mile and a half.to the east of Dunwich, the
site of which must at present be so far within the
sea.’* This city, once so flourishing and populous, is
now asmall village, with about twenty houses, and one
hundred inhabitants.

There is an old tradition, “ that the tailors sat in
their shops at Dunwich, and saw the ships in Yarmouth
Bay ;” but when we consider how far the coast at
Lowestoff Ness projects between these places, we
cannot give credit to the tale, which, nevertheless,
proves how much the inroads of the sea in times of old
had prompted men of lively imagination to indulge
their taste for the marvellous.

Gardner’s description of the cemeteries laid open
by the waves remind us of the scene which has been
so well depicted by Bewick+, and of which numerous
points on the same coast might have suggested the idea.
On the verge of a cliff, which the sea has undermined,
are represented the unshaken tower and western end
of an abbey. The eastern aisle is gone, and the
pillars of the cloister are soon to follow. The waves
have almost isolated the promontory, and invaded the
cemetery, where they have made sport with the mortal
relics, and thrown up a skull upon the beach. In the
foreground is seen a broken tombstone, erected, as its
legend tells, ‘“ to perpetuate the memory of one whose
name is obliterated, as is that of the county for which
he was ‘ Custos Rotulorum.’” A cormorant is perched
on the monument, defiling it, as if to remind some

* Consequences of the Deluge, Phys. Theol. Discourses.

+ History of British Birds, vol. ii. p. 220- Ed. 1821.
tT 3

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4l4 ENCROACHMENTS OF THE SEA ON [Book II.

moraliser, like Hamlet, of “ the base uses” to which
things sacred may be turned. Had this excellent artist
desired to satirise certain popular theories of geology,
he might have inscribed the stone to the memory of
some philosopher who taught “ the permanency of
existing continents” — “the era of repose” —*“ the
impotence of modern causes.”

South of Dunwich are two cliffs, called Great and
Little Cat Cliff. That which bears the name of Great
has become the smaller of the two, and is only fifteen
feet high, the more elevated portion of the hill having
been carried away ; on the other hand, the Lesser Cat
Cliff has gained in importance, for the sea has here
been cutting deeper into a hill which slopes towards
it. But at no distant period, the ancient names will
again become appropriate, for at Great Cliff the base
of another hill will soon be reached, and at Little Cat
Cliff the sea will, at about the same time, arrive at a
valley.

The incursions of the sea at Aldborough were for-
merly very destructive, and this borough is known to
have been once situated a quarter of a mile east of
the present shore. The inhabitants continued to build
farther inland, till they arrived at the extremity of
their property, and then the town decayed greatly ;
but two sand-banks, thrown up at a short distance,
now afford a temporary safeguard to the coast. Be-
tween these banks and the present shore, where the
current now flows, the sea is twenty-four feet deep on
the spot where the town formerly stood.

Continuing our survey of the Suffolk coast to the
southward, we find that the cliffs of Bawdsey and
Felixtow are foundering slowly, and that the point on
which Landguard Fort is built suffers gradual decay.

ch. VLJ THE EAST COAST OF ENGLAND. ALS

It appears that, within the memory of persons now
living, the Orwell river continued its course in a more
direct line to the sea, and entered to the north instead
of the south of the low bank on which the fort last
mentioned is built.

Essex. — Harwich, in Essex, stands on an isthmus,
which will probably become an island in little more
than half a century ; for the sea will then have made
a breach near Lower Dover Court, should it continue
to advance as rapidly as it has done during the last
fifty years. Within ten years, there was a considerable
space between the battery at Harwich, built twenty-
three years ago, and the sea; part of the fortification
has already been swept away, and the rest overhangs
the water. Since the year 1807, a field called the
Vicar’s Field, which belonged to the living of Harwich,
has been totally annihilated.*

At Walton Naze, in the same county, the cliffs,
composed of London clay, capped by the shelly sands
of the crag; reach the height of about 100 feet, and
are annually undermined by the waves. The old
churchyard of Walton has been washed away, and the
cliffs to the south are constantly disappearing.

Kent. —Isle of Sheppey-—On the coast bounding the

` estuary of the Thames, there are numerous examples
both of the gain and loss ofland. The Isle of Sheppey,
which is now about six miles long by four in breadth,
is composed of London clay. The cliffs on the north,
which are from sixty to eighty feet high, decay rapidly,
fifty acres having been lost within the last twenty years-
The church at Minster, now near the coast, is said to
have been in the middle of the island fifty years 48° oe
* On authority of Dr. Mitchell, F. G. S.
+ For this information I am indebted to W. Gunnel, Esq.
T 4

416 ENCROACHMENTS OF THE SEA ON [Book II.

and it has been conjectured that, at the present rate
of destruction, the whole isle will be annihilated in
about half a century. On the coast of the mainland
to the east of Sheppey is Herne Bay; a place still
retaining the name of a bay, although it is no longer
appropriate, as the waves and currents have swept
away the ancient headlands. There was formerly a
small promontory in the line of the shoals where the
present pier is built, by which the larger bay was
divided into two, called the Upper and Lower.*

Still farther east stands the church of Reculver,
upon a cliff composed of clay and sand, about twenty
feet high. Reculver (Regulvium), was an important
military station in the time of the Romans, and appears,
from Leland’s account, to have been, so late as Henry
VIL ’s reign, nearly one mile distant from the sea.

Fig. 19.

View of Reculver Church, taken in the year 1781.
1. Isle of Sheppy.
2. Ancient chapel now destroyed. The cottage between this
chapel and the cliff was demolished by the sea, in 1782.

* On the authority of W. Richardson, Esq., F. G. S.

`

Ch. VIJ THE EAST COAST OF ENGLAND. 417

In the “Gentleman’s Magazine”, there is a view of it,
taken in 1781, which still represents a considerable
space as intervening between the north wall of the
churchyard and the cliff. * Some time before the
year 1780, the waves had reached the site of the
ancient Roman camp, or fortification, the walls of
which had continued for several years after they were
undermined to overhang the sea, being firmly cemented
into one mass. They were eighty yards nearer the
sea than the church, and they are spoken of in the
« Topographica Britannica” in the year 1780, as hav-
ing recently fallen down. In 1804, part of the

Reculver Church, in 1834.

æ Vol. ii. New Series, 1809, p- 801.
T8

418 GOODWIN SANDS. [Book II.

churchyard with some adjoining houses was washed
away, and the ancient church, with its two lofty spires,
a well known land-mark, was dismantled and abandoned
as a place of worship. It is still standing (1834), but
would probably have been annihilated ere this, had not
the force of the waves been checked by an artificial
causeway of stones and large wooden piles driven into
the sands to break the force of the waves.*

Isle of Thanet.—The isle of ‘Thanet was, in the
time of the Romans, separated from the rest of Kent
by a navigable channel through which the Roman
fleets sailed on their way to and from London. Bede
describes this small estuary as being, in the beginning
of the eighth century, three furlongs in breadth ; and it
is supposed that it began to grow shallow about the
period of the Norman conquest. It was so far silted
up in the year 1485, that an act was then obtained to
build a bridge across it; and it has since become marsh
land with small streams running through it. On the
coast, Bedlam Farm, belonging to the hospital of that
name, has lost eight acres in the last twenty years,
the land being composed of chalk from forty to fifty
feet above the level of the sea. It has been computed,
that the average waste of the cliff between the North
Foreland and the Reculvers, a distance of about eleven
miles, is not less than two feet per annum. The chalk
cliffs on the south of Thanet, between Ramsgate and
Pegwell Bay, have on an average lost three feet per
annum for the ten last years (preceding 1830).

Goodwin Sands.— The Goodwin Sands lie opposite
this part of the Kentish coast. They are about ten
miles in length, and are in some parts three, and in
others seven miles distant from the shore ; and, for a

* Dr. Mitchell, Proceedings of Geol. Soc. vol. ii, No. 1.

Ch. VL] FORMATION OF THE STRAITS OF DOVER. 419

certain space, are laid bare at low water. That they
are a remnant of land, and not “a mere accumulation
of sea sand,” as Rennell imagined *, may be presumed
from the fact that, when the erection of a lighthouse
on this shoal was in contemplation by the Trinity.
Board in the year 1817, it was found, by borings, that
the bank consisted of fifteen feet of sand, resting on
blue clay. An obscure tradition has come down to us,
that the estates of Earl Goodwin, the father of Harold,
whe died in the year 1053, were situated here, and
some have conjectured that they were overwhelmed
by the flood mentioned in the Saxon chronicle, sub
anno 1099. The last remains of an island, consisting,
like Sheppey, of clay, may perhaps, have been carried
away about that time.

There are other records of waste in the county ot
Kent, as at Deal; and at Dover, where Shakspeare’s

* Geog. of Herod. vol. ii. p. 326.
T6

420 FORMATION OF THE STRAITS OF DOVER. [Book II.

cliff, composed entirely of chalk, has suffered greatly,
and continually diminishes in height, the slope of the
hill being towards the land. About the year 1810
there was an immense landslip from this cliff, by which
Dover was shaken as if by an earthquake, and a still
greater one in 1772.*

Straits of Dover. — In proceeding from the northern
parts of the German Ocean towards the Straits of
Dover, the water becomes gradually more shallow, so
that in the distance of about two hundred leagues we
pass from a depth of 120, to that of 58, 38, 24, and 18
fathoms. In the same manner the English Channel
deepens progressively from Dover to its entrance;
formed by the Land’s End of England, and the Isle
of Ushant on the Coast of France; so that the strait
between Dover and Calais may be said to part two
seas. +

Whether England was formerly united with France
has often been a favourite subject of speculation ; and
in 1753 a society at Amiens proposed this as a subject
of a prize essay, which was gained by the celebrated
Desmarest, then a young man. He founded his prin-
cipal arguments on the identity of composition of the
cliffs on the opposite sides of the channel, on a sub-
marine chain extending from Boulogne to Folkestone,
only fourteen feet under low water, and on the identity
of the noxious animals in England and France, which
could not have. swum across the Straits, and would
neyer have been introduced by man. He also attri-
buted the rupture of the isthmus to the preponderating

+ Dodsley’s Ann. Regist. 1779,
t Stevenson on the Bed of the German Ocean, — Ed. Phil,
Journ., No. v. p. 45.

Ch. V1] ENCROACHMENTS OF THE SEA. 421

violence of the current from the north* It will
hardly be disputed that the ocean might have effected
a breach through the land which, in all probability,
once united this country to the Continent, in the same
manner as it now gradually forces a passage through
rocks of the same mineral composition, and often many
hundred feet high, upon the coast.

Although the time required for such an operation
was probably very great, yet we cannot estimate it by
reference to the present rate of waste on both sides
of the Channel; for when, in the thirteenth century,
the sea burst through the isthmus of Staveren, which
formerly united Friesland with North Holland, it
opened, in about one hundred years, a strait more
than half as wide as that which divides England from
France, after which the dimensions of the new channel
remained almost stationary. The greatest depth of
the straits between Dover and Calais is twenty-nine
fathoms, which exceeds only by one fathom the great-
est depth of the Mississippi at New Orleans. If the
moving column of water in the great American river,
which, as was before mentioned, does not flow rapidly,
can maintain an open passage to that depth in its
alluvial accumulations, still more might a channel of
the same magnitude be excavated by the resistless
force of the tides and currents of “ the ocean stream,”

Totam meyer ohevos Nxexyolo.

In framing these speculations, however, we must not
overlook the great effects which particular combin-
ations of causes might produce without violence. The
chalk supposed in this instance to have been removed,
was of itself a marine deposit, and must at some

* Cuvier, Eloge de Desmarest.

4.99 ENCROACHMENTS OF THE SEA ON [Book II.

period have emerged from the deep. It may have
been upraised gradually, as the coast of Sweden, with
the bed of the adjacent ocean and Baltic sea, are now |
rising *; or there may have been oscillations of level
in the lands once connecting France and England. In
that case, and especially if the movements were slow,
a great amount of. excavation may have been pro-
duced by a comparatively feeble power exerted by
waves and currents cutting through successive portions
of the chalk as it emerged. And here I may mention,
that strata of chalky rubble and sand found at the
base of the cliffs near Dover and Brighton, seem to
indicate some changes in the relative level of sea and
land since our coasts acquired a considerable part of
their actual height and contour.+

At Folkestone, the sea undermines the chalk and
‘subjacent strata. About the year 1716 there was a
remarkable sinking of a track of land near the sea, so
that houses became visible at points near the shore
from whence they could not be seen previously. In
the description of this subsidence in the Philosophical
Transactions, it is said, “ that the land consisted of a
solid stony mass (chalk), resting on wet clay (gault),
so that it slid forwards towards the sea, just as a ship
is launched on tallowed planks.” It is also stated that,
within the memory of persons then living, the cliff
there had been washed away to the extent of ten
rods.{

Encroachments of the sea at Hythe are also on
record; but between this point and Rye there has
been a gain of land within the times of history; the
rich level tract called Romney Marsh, or Dungeness,

* See Book ii. chap. 17. + See Book iv. chap. 22.
ł Phil. Trans., 1716.

Ch. VLJ THE SOUTH COAST OF ENGLAND. 423

about ten miles in width and five in breadth, and
formed of silt, having received great accession. It has
been necessary, however, to protect it from the sea,
from the earliest periods, by embankments, the towns
of Lydd and Romney being the only parts of the
marsh above the level of the highest tides.* These
additions of land are exactly opposite that part of the
English Channel where the conflicting tide-waves from
the north and south meet ; for, as that from the north
is, for reasons already explained, the most powerful,
they do not neutralize each cther’s force till they ar-
rive at this distance from the straits of Dover. Rye,
on the south of this tract, was once destroyed by the
sea, but it is now two miles distant from it. The
neighbouring town of Winchelsea was destroyed in
the reign of Edward I., the mouth of the Rother
stopped up, and the river diverted into another channel.
In its old bed an ancient vessel, apparently a Dutch
merchantman, was recently found. It was built en-
tirely of oak, and much blackened.+ Large quantities
of hazel nuts, peat, and wood are found in digging in
Romney marsh.

South Coast of England. — To pass over some points
near Hastings, where the cliffs have wasted at several
periods, we arrive at the promontory of Beachy Head.
Here a mass of chalk, three hundred feet in length,
and from seventy to eighty in breadth, fell, in the
year 1813, with a tremendous crash ; and similar slips
have since been frequent.

Sussex.— About a mile to the west of the town of
Newhaven the remains of an ancient entrenchment

* On the authority of Mr. J. Meryon, of Rye.

+ Edin. Journ. of Sci., No. xix. p. 56-
+ Webster, Geol. Trans., vol. ii. p. 192.

4.24: ENCROACHMENTS OF THE SEA ON [Book IT.

are seen, on the brow of Castle Hill. This earth-work,
supposed to be Roman, was evidently once of con-
siderable extent and of an oval form, but the greater
part has been cut away. The cliffs, which are under-
mined here, are high; more than one hundred feet of
chalk being covered by tertiary clay and sand, from
sixty to seventy feet in thickness. In a few centuries
the last vestiges of the plastic clay formation on the
southern borders of the chalk of the South Downs on
this coast will be annihilated, and future geologists
will learn, from historical documents, the ancient
geographical boundaries of this group of strata in that
direction. On the opposite side of the estuary of the
Ouse, on the east of Newhaven harbour, a bed of
shingle, composed of chalk flints, derived from the
waste of the adjoining cliffs, had accumulated at Sea-
ford for several centuries. In the great storm of No-
vember, 1824, this bank was entirely swept away, and
the town of Seaford inundated. Another great beach
of shingle is now forming from fresh materials.

The whole coast of Sussex has been incessantly
encroached upon by the sea from time immemorial ;
and, although sudden inundations only, which over-
whelmed fertile or inhabited tracts, are noticed in his-
tory, the-records attest an extraordinary amount of
loss. During a period of no more than eighty years,
there are notices of about twenty inroads, in which
tracts of land of from twenty to four hundred acres in
extent were overwhelmed at once; the value of the
tithes being mentioned by Nicholas, in his Taxatio
Ecclesiastica.* In the reign of Elizabeth, the town
of Brighton was situated on that tract where the chain

* Mantell, Geology of Sussex, p. 293.

Ch. VLJ THE SOUTH COAST OF ENGLAND. 425

pier now extends into the sea. In the year 1665
twenty-two tenements had been destroyed under the
cliff. At that period there still remained under the
cliff 113 tenements, the whole of which were over-
whelmed in 1703 and 1705. No traces of the ancient
town are now perceptible, yet there is evidence that
the sea has merely resumed its ancient position at the
base of the cliffs, the site of the old town having been
merely a beach abandoned by the ocean for ages.

Hampshire — Isle of Wight.—It would be endless
to allude to all the localities on the Sussex and
Hampshire coasts where the land has given way;
but I may point out the relation which the geological
structure of the Isle of Wight bears to its present
shape, as attesting that the coast owes its outline
to the continued action of the sea. Through the
middle of the island runs a high ridge of chalk strata,
in a vertical position, and in a direction east and west.
This chalk forms the projecting promontory of Culver
Cliff on the east, and of the Needles on the west;
while Sandown Bay on the one side, and Compton
Bay on the other, have been hollowed out of the
softer sands and argillaceous strata, which are inferior
to the chalk.

The same phenomena are repeated in the Isle of
Purbeck, where the line of vertical chalk forms the
projecting promontory of Handfast Point; and Swanage
Bay marks the deep excavation made by the waves in.
the softer strata, corresponding to those of Sandown
Bay. |

Hurst- Castle Bank.— The entrance of the channel
called the Solent is becoming broader by the waste of
the cliffs in Colwell Bay; it is crossed for more than
two thirds of its width by the shingle bank of Hurst

426 ENCROACHMENTS OF THE SEA ON Book II

Castle, which is about seventy yards broad and twelve
feet high, presenting an inclined plane to the west.
This singular bar consists of a bed of rounded chalk
flints, resting on a submarine argillaceous base. The
flints and a few other pebbles, intermixed, are exclu-
sively derived from the waste of Hordwell, and other
cliffs to the westward, where tertiary strata, capped
with a covering of chalk flints, from five to fifty feet
thick, are rapidly undermined.

Storm of Nov. 1824.—In the great storm of No-
vember, 1824, this bank of shingle was moved bodily
forwards for forty yards towards the north-east ; and
certain piles which served to mark the boundaries of
two manors, were found, after the storm, on the oppo-
site side of the bar. At the same time many acres of
pasture land were covered by shingle, on the farm of
Westover, near Lymington.

The cliffs between Hurst Shingle Bar and the mouth
of the Stour and Avon are undermined continually.
, Within the memory of persons now living, it has been
necessary thrice to remove the coast-road farther in-
land. The tradition, therefore, is probably true, that
the church of Hordwell was once in the middle of
that parish, although now very near the sea. The
promontory of Christ Church Head gives way slowly.
It is the only point between Lymington and Poole
Harbour in Dorsetshire, where any hard stony masses
occur in thé cliffs. Five layers of large ferruginous
concretions, somewhat like the septaria of the London
clay, have occasioned a resistance at this point, to
which we may ascribe this headland. In the mean
time, the waves have cut deeply into the soft sands
and loam of Poole Bay ; and, after severe frosts, great
landslips take place, which, by degrees, become en-

Ch. V1.J THE SOUTH COAST OF ENGLAND. 497

larged to narrow ravines, or chines, as they are

called, with vertical sides. One of these chines near
Boscomb, has been deepened twenty feet within a few
years. At the head of each there is a spring, the
waters of which have been chiefly instrumental in
producing these narrow excavations, which are some-
times from 100 to 150 feet deep.

Isle of Portland.— The peninsulas of Purbeck and
Portland are continually wasting away. In the latter,
the soft argillaceous substratum (Kimmeridge clay)
hastens the dilapidation of the superincumbent mass
of limestone.

In 1665 the cliffs adjoining the principal quarries in
Portland gave way to the extent of one hundred yards,
and fell into the sea; and in December, 1734, a slide
to the extent of 150 yards occurred on the east side
of the isle, by which several skeletons, buried between
slabs of stone, were discovered. But a much more
memorable occurrence of this nature, in 1792, occa-
sioned probably by the undermining of the cliffs, is
thus described in Hutchins’s History of Dorsetshire: —
« Early in the morning the road was observed to crack:
this continued increasing, and before two o'clock the
ground had sunk several feet, and was in one con-
tinued motion, but attended with no other noise than
what was occasioned by the separation of the roots
and brambles, and now and then a falling rock. At
night it seemed to stop a little, but soon moved again ;
and before morning, the ground, from the top of the
cliff to the water-side, had sunk in some places fifty
feet perpendicular. The extent of ground that moved
was about a mile and a quarter from north to south,
and six hundred yards from east to west.

Formation of the Chesil Bank. — Portland is con-

428 CHESIL BANK. [Book II.

nected with the main land by the Chesil Bank, a ridge
of shingle about seventeen miles in length, and, in
most places, nearly a quarter of a mile in breadth.
The pebbles forming this immense barrier are chiefly
of limestone; but there are many of quartz, jasper,
chert, and other substances, all loosely thrown to-
gether. What is singular, they gradually increase in
size from west to east—from the Portland end of
the bank to that which attaches to the main land.
The formation of this bar may probably be ascribed,
like that of Hurst Castle, to a meeting of tides, or to
a submarine shoal or reef between the peninsula and
the land. We have seen that slight obstructions in
the course of the Ganges will cause, in the course of a
man’s life, islands many times larger than the whole
of Portland, and which, in some cases, consist of a
column of earth more than one hundred feet deep.
In like manner those transported materials which are
annually swept away from large tracts of our coast,
may give rise, wherever they encounter any impedi-
ment in their course, to banks of sand and shingle
many miles in length. The course of the shingles in
Dorsetshire, and on the shores of Sussex and Kent,
appears to be from west to east, the prevalent winds,
and, consequently, the chief force of the waves, being
in that direction.* The storm of 1824 burst over the
Chesil Bank with great fury, and the village of
Chesilton, built upon its southern extremity, was
overwhelmed, with many of the inhabitants. The
fundamental rocks whereon the shingle rests are found
at the depth of a few yards only below the level of
the sea.

* See Palmer on Motion of Shingle Beaches, Phil. Trans.,
1834, p. 568.

Ch. VL] DORSETSHIRE — DEVONSHIRE — CORNWALL. 429

This same storm carried away part of the Break-
water, at Plymouth, and huge masses of rock from two
- to five tons in weight, were lifted from the bottom of
the weather side, and rolled fairly to the top of the
pile. One block of limestone, weighing seven tons,
was washed round the western extremity of the Break-
water, and carried 150 feet.* It was in the same
month, and also during a spring-tide, that a great
flood is mentioned on the coasts of England, in the
year 1099. Florence of Worcester says, “ On the third
day of the nones of Nov. 1099; the sea came out upon
the shore, and buried towns and men very many, and
oxen and sheep innumerable.” We also read in the
Saxon Chronicle, already cited for the year 1099,
« This year eke on St. Martin’s mass day, the 11th of
Novembre, sprung up so much of the sea flood, and
so myckle harm did, as no man minded that it ever
afore did, and there was the ylk day a new moon.”

Dorsetshire — Devonshire — Cornwall. — At Lyme
Regis, in Dorsetshire, the “ Church Cliffs,” as they
are called, consisting of lias about one hundred feet in
height, have gradually fallen away, at the rate of one
yard a year, since 1800.+ The cliffs of Devonshire
and Cornwall, which are chiefly composed of hard rocks,
decay less rapidly. Near Penzance in Cornwall, there
is a projecting tongue of land, called the “ Green,”
formed of granitic sand, from which more than thirty
acres of pasture land have been gradually swept away
in the course of the last two or three centuries. { It

* De la Beche, Geol. Man. p. 82.

+ This ground was measured by Dr. Carpenter of Lyme, in
1800, and again in 1829, as I am informed by Miss Mary Anning
of Lyme, well known by her discoveries in fossil remains.

ł Boase, Trans. Royal Geol, Soc. of Cornwall, vol. ii. p. 129.

430 WEST COAST OF ENGLAND. [Book II.

is also said that, St. Michael’s Mount, now an insular
rock, was formerly situated in a wood, several miles
from the sea; and its old Cornish name (Caraclowse
in Cowse) signifies, according to Carew, the Hoare
Rock in the Wood.* Between the Mount and New-
lyn there is seen under the sand black vegetable
mould, full of hazel nuts, and the branches, leaves;
roots, and trunks of forest trees, all of indigenous spe-
cies. This vegetable stratum has been traced seaward
as far as the ebb permits, and seems to indicate some
ancient estuary on that shore.

Tradition of loss of land in Cornwall.— The oldest
historians mention a celebrated tradition in Cornwall,
of the submersion of the Lionnesse, a country which
formerly stretched from the Land’s End to the Scilly
Islands. The tract, if it existed, must have been
thirty miles in length, and perhaps ten in breadth.
The land now remaining on either side is from two
hundred to three hundred feet high ; the intervening
sea about three hundred feet deep. Although there is
no evidence for this romantic tale, it probably origin-
ated in some catastrophe occasioned by former inroads
of the Atlantic upon this exposed coast.+

West coast of England.— Having now brought to-
gether an ample body of proofs of the destructive
operations of the waves, tides, and currents, on our
eastern and southern shores, it will be unnecessary to
enter into details of changes on the western coast, for
they present- merely a repetition of the same pheno-
mena, and in general on an inferior scale. On the
borders of the estuary of the Severn the flats of
Somersetshire and Gloucestershire have received

* Boase, Trans. Royal Geol. Soc. of Cornwall, vol. ii. p. 135.
_ + Ibid. p. 130.

Ch. VL] Loss OF LAND ON THE COAST OF FRANCE. 431

enormous accessions, while, on the other hand, sub-
marine forests on the coast of Cheshire and Lancashire
` indicate the overflowing of alluvial tracts. Since the
year 1764, the coast of Cheshire between the rivers
Mersey and Dee has lost many hundred yards, and
some afirm more than half a mile, by the advance of
the sea upon the abrupt cliffs of red clay and marls.
Within the period above mentioned several light-houses
have been successively abandoned.* ‘There are tra-
ditions in Pembrokeshire + and Cardiganshire} of far
greater losses of territory than that which the Lion-
nesse tale of Cornwall pretends to commemorate.
They are all important, as demonstrating that the
earliest inhabitants were familiar with the phenomenon
of incursions of the sea.

Loss of land on the coast of France.— The French
coast, particularly that of Brittany, where the tides
rise to an extraordinary height, is the constant prey of
the waves. In the ninth century many villages and
woods are reported to have been carried away, the
coast undergoing great change, whereby the hill of St.
Michael was detached from the main land. The
parish of Bourgneuf, and several others in that neigh-
bourhood, were overflowed in the year 1500. In 1735,
during a great storm, the ruins of Palnel were seen
uncovered in the sea.§ A romantic tradition, more-
over, has descended from the fabulous ages of the de-
struction of the south-western part of Brittany, whence
we may probably infer some great inroad of the sea at

a remote period. \|
* Stevenson, Jameson’s Ed. new Phil. Journ. No. 8- p- 386-
+ Camden, who cites Gyraldus, also Ray, “ On the Deluge,”
Phys. Theol. p- 228.

+ Meyrick’s Cardigan.
§ Von Hoff, Geschichte, &e. vol. i. p49 || Ibid. p. 48.

GLOSSARY

OF GEOLOGICAL AND OTHER SCIENTIFIC TERMS USED
IN THIS WORK.

Acrernatous. The Acephala are that division of molluscous
animals which, like the oyster and scallop, are without heads.
The class Acephala of Cuvier comprehends many genera of
animals with bivalve shells, and a few which are devoid of
shells. Etym., a, @, without, and xepadn, cephale, the head.

ApırocirE. A substance apparently intermediate between fat
and wax, into which dead animal matter is converted when
buried in the earth, and in a certain stage of decomposition.
Etym., adeps, fat, and cera, wax.

Arrme., See “ Felspar.”

ALEMBIC, An apparatus for distilling.

Area. An order or division of the cryptogamic class of plants.
The whole of the sea-weeds are comprehended under this
division, and the application of the term in this work is to
marine plants. Etym., alga, sea-weed.

Auzuviat. The adjective of alluvium, which see.

Autuvion. Synonymous with alluvium, which see.

Atiuvium. Earth, sand, gravel, stones, and other transported
matter which has been washed away and thrown down by
rivers, floods, or other causes, upon land not permanently
submerged beneath the waters of lakes or seas. Etym.,
alluo, to wash upon. For a further explanation of the term
as used in this work, see Vol. III. p. 196., and Vol. IV.
p. 44.

Axum-stone, ALUMEN, Axuuminous. Alum is the base of pure
clay, and strata of clay are often met with containing much
iron-pyrites. When the latter substance decomposes, sul-
phuric acid is produced, which unites with the aluminous earth

VOL. Ie U

ABA GLOSSARY.

of the clay to form sulphate of alumine, or common alum.
Where manufactories are established for obtaining the alum,
the indurated beds of clay employed are called Alum-stone.

Ammonire. An extinct and very numerous genus of the order
of molluscous animals called Cephalopoda, allied to the
modern genus Nautilus, which inhabited a chambered shell,
curved like a coiled snake. Species of it are found in all
geological periods of the secondary strata; but they have not
been seen in the tertiary beds. They are named from their
resemblance to the horns on the statues of Jupiter Ammon.

Amorruous. Bodies devoid of regular form. Etym., a, a, with-
out, and moppn, morphe, form.

Amyepator. One of the forms of the trap-rocks, in which
agates and simple minerals appear to be scattered like almonds
in a cake. Etym., auvySara, amygdala, an almond.

Anatcrmr. <A simple mineral of the Zeolite family, also called
Cubizite, of frequent occurrence in the trap-rocks.

ANALOGUE., <A body that resembles or corresponds with another
body. A recent shell of the same species as a fossil-shell is
the analogue of the latter.

ÅNOPLOTHERE, ÅNOPLOTHERIUM. A fossil extinct quadruped
belonging to the order Pachydermata, resembling a pig. It
has received its name because the animal must have been
singularly wanting in means of defence, from the form
of its teeth and the absence of claws, hoofs, and horns.
Etym., avordos, anoplos, unarmed, and npon, therion, a
wild beast.

Axtaconisr Powers.
the one counteracting that of the other, by which a kind of

\ equilibrium or balance is maintained, and the destructive
effect prevented that would be produced by one. operating
without a check.

Anrenna&. The articulated horns with which the heads of in-
sects are invariably furnished.

ANTHRACITE, A shining substance like black-lead ; a species of
mineral charcoal. Etym., aypat, anthrar, coal.

ÄNTHRÄCOTHERIUMe A name given to an extinct quadruped,
supposed to belong to the Pachydermata, the bones of which
were found in lignite and coal of the tertiary strata. Etym.,
avout, anthrax, coal, and Supioy, therion, wild beast.

Two powers in nature, the action. of

GLOSSARY. 435

ANTHROPOMORPHOUS. Having a form resembling the human,
Etym., avbpwmos, anthropos, a man, and uoppn, morphe,
form.

ANTICLINAL Axis. If a range of hills, or a valley, be com-
posed of strata, which on the two’ sides dip in opposite
directions, the imaginary line that lies between them, to-
wards which the strata on each side rise, is called the anti-

clinal axis. In a row of houses with steep roofs facing the
south, the slates represent inclined strata, dipping north and
south, and the ridge is an east and west anticlinal axis. In

the accompanying diagram, a, a are the anticlinal, and 6, b
the synclinal lines. Etym., avr, anti, against, and xvw, clino,
to incline.

Antiseptic. Substances which prevent corruption in animal and
vegetable matter, as common salt does, are said to be anti-
septic. Etym., avti, against, and cnw, sepo, to putrefy.

Arenacrous. Sandy. Etym., arena, sand.

ArGILLACEOUS, Clayey, composed of clay. Etym., argilla,
clay.

ARRAGONITE. A simple mineral, a variety of carbonate of lime,
so called from having been first found in Arragon, in Spain.

Auvaere. A simple mineral of a dark green, or black colour,
which forms’a constituent part of many varieties of volcanic
rocks. Name applied by Pliny to a particular mineral,
from the Greek duyn, auge, lustre.

Avatancues. Masses of snow which, being detached from great
heights in the Alps, acquire enormous bulk by fresh accumu-
lations as they descend; and when they fall into the valleys
below often cause great destruction. They are also called
“lavanges, and lavanches, in the dialects of Switzerland.

Basar. One of the most common varieties of the Trap-rocks,
It is a dark green or black stone, composed of augite and
felspar, very compact in texture, and of considerable hard-
ness, often found in regular pillars of three or more sides

Gen

Fee anna tee ke en a cpa MT

GLOSSARY.

called basaltic columns. Remarkable examples of this kind
are seen at the Giant’s Causeway, in Ireland, and at Fingal’s
Cave, in Staffa, one of the Hebrides. The term is used by
Pliny, and is said to come from basal, an Æthiopian word
signifying iron. The rock often contains much iron.

“ Basin” of Paris, “ Basın” of London. Deposits lying in a

` hollow or trough, formed of older rocks ; sometimes used in
geology almost synonymously with “ formations,” to express
the deposits lying in a certain cavity or depression in older
rocks.

Briemnire. An extinct genus of the order of molluscous
animals called Cephalopoda, having a long, straight, and
chambered conical shell, Etym., @ereuvov belemnon, a
dart.

Bitumen. Mineral pitch, of which the tar-like substance which
is often seen to ooze out of the Newcastle coal when on the
fire, and which makes it cake, is a good example. Etym.,
bitumen, pitch. +

Bituminous Suare. An argillaceous shale, much impregnated
with bitumen, which is very common in the coal measures.

Bienpr. A metallic ore, a compound of the metal zinc with

sulphur. It is often found in brown shining crystals ; hence
its name among the German miners, from the word blenden,
to dazzle.

Buurrs. High banks presenting a precipitous front to the sea
or a river. A term used in the United States of North
America.

Borryorwat. Resembling a bunch of grapes. Etym., Borpus,
botrys, a bunch of grapes, and stdo¢, eidos, form.

Bovutpers. A provincial term for large rounded blocks of stone
lying on the surface of the ground, or sometimes imbedded
in loose soil, different in composition from the rocks in their
vicinity, and which have been therefore transported from a
distance.

Breccia, A rock composed of angular fragments connected
together by lime or other mineral substance. An Italian
term.

Cauc Sinrer. A German name for the deposits from springs
holding carbonate of lime in solution — petrifying springs.
Etym., kalk, lime, sintern, to drop.

GLOSSARY. 4.37

CALCAIRE Grossier. An extensive stratum, or yather series of
strata, found in the Paris Basin, belonging to the Eocene
tertiary period. See Table I. E, Vol. IV. p. 302, Etym,
calcaire, limestone, and grossier, coarse.

CALCAREOUS ROCK. Limestone. Etym., calx, lime.

CALCAREOUS SPAR. Crystallized carbonate of lime,

CALCEDONY. A siliceous simple mineral, uncrystallized. Agates
are partly composed of calcedony. ;

Carson. An undecomposed inflammable substance, one of the
simple elementary bodies. Charcoal is almost entirely com-
posed of it. Etym., carbo, coal.

CARBONATE of Lime. Lime combines with great avidity with
carbonic acid, a gaseous acid only obtained fluid when united
with water, —and all combinations of it with other sub-
stances are called Carbonates. All limestones are carbonates
of lime, and quick lime is obtained by driving off the car-
bonic acid by heat.

Carzonatep Srrines. Springs of water, containing carbonic

acid gas. They are very common, especially in volcanic
countries; and sometimes contain so much gas, that if a
little sugar be thrown into the water it effervesces like soda-
water.

Carzonic Acw Gas. A natural gas which often issues from
the ground, especially in volcanic countries. Etym., carbo,
coal; because the gas is obtained by the slow burning of
charcoal.

Carponrrekous. A term usually applied, in a technical sense, to
an ancient group of secondary strata (see Table I. M, Vol. IV. .
p- 305.) ; but any bed containing coal may be said to-be car-
poniferous. Etym., carbo, coal, and Jero, to bear.

Caractysm. A deluge. Etym., narakrv€o, catacluzo, to deluge.

Crpuatoropa. A class of molluscous animals, having their organs
of motion arranged round their head. Etym., #epean,
cephale, head, and roða, poda, feet.

Cxracea. An order of vertebrated mammiferous animals inha-
biting the sea. The whale, dolphin, and narwal are examples.
Etym., cete, whale.

Cuatx. A white earthy limestone, the uppermost of the second-
ary series of strata. See Table I. F, Vol. IV., p. 302.

Cuert. A siliceous mineral, nearly allied to calcedony and flint,

vu 3

438 GLOSSARY,

but less homogeneous and simple in texture. A gradual pas-
sage from chert to limestone is not uncommon.

Curoriic SAND. Sand coloured green by an admixture of the
simple mineral chlorite. ‘Etym., xAwpos, chloros, green.
CiravacE. Certain rocks, usually called slate-rocks, may be
cleaved into an indefinite number of thin laminz which are
parallel to each other, but which are generally not parallel to
the planes of the true strata or layers of deposition. The
planes of cleavage, therefore, are distinguishable from those
of stratification ; and they also differ from joints, which are
fissures or lines of parting, at definite distances, and often at
right angles to the planes of stratification. The partings
which divide columnar basalt into prisms are joints. The
masses of rock included between joints cannot be cleaved
into an indefinite number of lamine or slates, having their
planes of cleavage parallel to the joints. See first part of

Chap. xxvii. Book iv.

Curxxsronr, ‘called also phonolite, a felspathic rock of the trap

family, usually fissile. It is sonorous when struck with a
hammer, whence its name.

Coat Formation. This term is generally understood to mean
the same as the Coal Measures. See Table I., M, Vol. IV.
p. 305. There are, however, “ coal formations” in all the
geological periods, wherever any of the varieties of coal forms
a principal constituent part of a group of strata,

Cortrorrera. An order of insects (Beetles) which have four
wings, the upper pair being crustaceous and forming a
shield. Etiyn., xoAeos, coleos, a sheath, and mTepoy, pteron,
a wing. r

Conrormazsie. When the planes of one set of strata are gene-
rally parallel to those of another set which are in contact,
they are said to be conformable. Thus the set a, b,
Fig. 139., Vol. IV. p. 120., rest conformably on the in-
ferior set c, d; but c, d rest unconformably on E.

Conexrnrrs. Species which belong to the same genus.

CONGLOMERATE OR Puppinesronz. Rounded water-worn frag-
ments of rock or pebbles, cemented together by another
mineral substance, which may be of a siliceous, calcareous,
or argillaceous nature. Htym., con, together, glomero, to heap.

Coxirerz. An order of plants which, like the fir and pine, bear

GLOSSARY. 439

cones or tops in which the seeds are contained. Etym.,
conus, cone, and fero, to bear.

Cooms. A provincial name in different parts of England for a -
valley on the declivity of a hill, and which is generally with-
out water.

Cornsrasa. A rubbly limestone, forming a soil extensively cul-
tivated in Wiltshire for the growth of corn. It is a provin-
cial term adopted by Smith. Brash is derived from brecan,
Saxon, to break. See Table L., H, Vol. IV. p. 303.

Cornsrons. A provincial name for a red limestone, forming a
subordinate bed in the Old Red Sandstone group-

Cosmocony, CosMoLocy. Words synonymous in meaning, ap-
plied to speculations respecting the first origin or mode of
creation of the earth. Etym., Koopos, kosmos, the world, and
yon, ZONCE, generation, or Ao'yos, logos, discourse.

Crac. A provincial name in Norfolk and Suffolk for a deposit,
usually of gravel, belonging to the Older Pliocene period.
See Table I., C, Vol. IV. p. 301-

Craver. The circular cavity at the summit of a volcano, from

which the volcanic matter is ejected. Etym., crater, a great

cup or bowl.

Creraczous. Belonging to chalk. Etym., creta, chalk.

Cror Our. A miner’s or mineral surveyor’s term, to express the
rising up or exposure at the surface of a stratum or series of
strata.

Crust or THE EARTH. See “ Earth’s crust.”

Crustacea, Animals having a shelly coating or crust which
they cast periodically. Crabs, shrimps, and lobsters, are
examples.

Cryproaamic. A name applied to a class of plants, such as ferns,
mosses, sea-weeds, and fungi, in which the fructification
or organs of reproduction are concealed. Etym., xpu™T0s;
kryptos, concealed, and yapos, gamos, marriage.

Crystats. Simple minerals are frequently found in regular
forms, with facets like the drops of cut glass of chandeliers.
Quartz being often met with in rocks in such forms, and
beautifully transparent like ice, was called. rock-crystal,
KpvoTAAAOS, crystallos, being Greek for ice. Hence the
regular forms of other minerals are called crystals, whether
they be clear or opake.

U 4

440 GLOSSARY. 7

Crysrattizep. A mineral which is found in regular forms or
crystals is said to be crystallized.

Crysratuine. The internal texture which regular crystals ex-
hibit when broken, or a confused assemblage of ill-defined
crystals. Loaf-sugar and statuary-marble have a crystalline
texture. Sugar-candy and calcareous spar are crystallized.

Cycapra. An order of plants which are natives of warm cli-
mates, mostly tropical, although some are found at the Cape
of Good Hope. They have a short stem, surmounted by a
peculiar foliage, termed pinnated fronds by botanists, which
spreads in a circle. The term is derived from kukas, cycas,
a name applied by the ancient Greek naturalist Theophrastus
to a palm.

Cyrrracem. A tribe of plants answering to the English sedges ;
they are distinguished from grasses by their stems being solid,
and generally triangular, instead of being hollow and round.
Together with graminee they constitute what writers on bota-
nical geography often call glumacee.

Dezactz. A great rush of waters, which, breaking down all op-
„posing barriers, carries forward the broken fragments of
rocks, and spreads them in its course. Etym., débacler,
French, to unbar, to break up as a river does at the cessation
of a long-continued frost.

Deira. When a great river, before it enters the sea, divides into
separate streams, they often diverge and form two sides of a
triangle, the sea being the base. The land included by the
three lines, and which is invariably alluvial, was first called,
in the case of the Nile, a delta, from its resemblance to the
letter of the Greek alphabet which goes by that name A.
Geologists apply the term to alluvial land formed by a river
at its mouth, without reference to its precise shape.

Denupation. The carrying away by the action of running water
of a portion of the solid materials of the land, by which infe-
rior rocks are laid bare. Etym., denudo, to lay bare.

Desiccation. The act of drying up. Etym., desicco, to dry up.

Deoxipizep, Dxoxtparep. Deprived of oxygen. Disunited
from oxygen.

Diaconat STRATIFICATION. For an explanation of this term, see
Vol. IV. p. 79.

GLOSSARY. 44l

Dicoryurponous. A grand division of the vegetable kingdom,
founded on the plant having two cotyledons or seed-lobes.
Etym., dis, dis, double, and koTvandov, cotyledon.

Dixzs. When a mass of the unstratified or igneous rocks, such as
granite, trap, and lava, appears as if injected into a great rent
in the stratified rocks, cutting across the strata, it forms a
dike; and as they are sometimes seen running along the
ground, and projecting, like a wall, from the softer strata on
poth sides of them having wasted away, they are called in the
north of England and in Scotland dikes, the provincial name
for wall. It is not easy to draw the line between dikes and
veins. The former are generally of larger dimensions, and
have their sides parallel for considerable distances; while
veins have generally many ramifications, and these often thin

away into slender threads.

Dituvium. Those accumulations of gravel and loose materials
which, by some geologists, are said to have been produced by
the action of a diluvian wave or deluge sweeping over the

surface of the earth. Etym., diluvium, deluge.

Dre. When a stratum does not lie horizontally, but is inclined,
it is said to dip towards some point of the compass, and the
angle it makes with the horizon is called the angle of dip or
inclination.

Dirrera. An order of insects, comprising those which have only
two wings. Etym., dis, dis, double, and mrepoy, pteron,
wing.

Doxerrre. One of the varieties of the trap-rocks, composed of
augite and felspar.

Dotomitsz. A crystalline limestone, containing magnesia as a
constituent part. Named after the French geologist Dolo-
mieu.

Durzs. Low hills of blown sand that skirt the shores of Hol-
land, England, Spain, and other countries.

Earrs’s Crust. Such superficial parts of our planet as are ac-
cessible to human observation.

Enyrra. The wing-sheaths, or upper crustaceous membranes,
which form the superior wings in the tribe of beetles. They
cover the body, and protect the true membranous wing.
Etym., eAvTpov, elytron, a sheath,

U &

442 GLOSSARY.

Eocene. See explanation of this word, Vol. III. p. 370.

Escarrment. ‘The abrupt face of a ridge of high land. Etym.,
escarper, French, to cut steep.

Estuaries. -Inlets of the land, which are entered both by rivers
and the tides of the sea. Thus we have the estuaries of the `
Thames, Severn, Tay, &c. Etym., æstus, the tide.

Exrrrimentum Crucis. A decisive experiment, so called be-
cause, like a cross or direction post, it directs men to true
knowledge; or, as some explain it, because it is a kind of
torture whereby the nature of the thing is extorted, as it were,
by violence.

Exuvia. Properly speaking, the transient parts of certain animals,
which they put off or lay down to assume new ones, as ser-
pents and caterpillars shift their skins; but in geology it
refers not only to the cast-off coverings of animals, but to
fossil shells and other remains which animals have left in the
strata of the earth. Etym., exuere, to put off or divest.

Fatuns. A French provincial name for some tertiary strata
abounding in shells in Touraine, which resemble in litho-
logical characters the ‘‘ crag” of Norfolk and Suffolk.

Fautt, in the language of miners, is the sudden interruption of
the continuity of strata in the same plane, accompanied
by a crack or fissure varying in width from a mere line to
several feet, which is generally filled with broken stone,

The strata a, b,
c, &c., must at
one time have

SOE A ER „ been continu-

ous; but a frac-

ture having

taken place at

the fault F,

either by the
upheaving of the portion A, or the sinking of the portion B,
the strata were so displaced that the bed a in B is many
feet lower than the same bed a in the portion A.

Fauna. The various kinds of animals peculiar to a country con-
stitute its Fauna, as the various kinds of plants constitute

GLOSSARY. 443

its Frosa. The term is derived from the Fant, or rural
deities, in Roman Mythology.

Fersrar. A simple mineral, which, next to quartz, constitutes
the chief material of rocks. The white angular portions in
granite are felspar. This mineral always contains some
alkali in its composition. In common felspar the alkali is
potash; in another variety, called Albite or Cleavlandite, it is
soda. Glassy felspar is a term applied when the crystals
have a considerable degree of transparency. Compact felspar
is a name of more vague signification. The ‘substance so
called appears to contain both potash and soda.

Fetspatuic. Of or belonging to felspar.

Ferrucrovs. Any thing containing iron. Etym., ferrum, iron.

Frorrz Rocxs. A German term applied to the secondary strata
by the geologists of that country, because these rocks were
supposed to occur most frequently in flat horizontal beds.
Etym., flotz, a layer or stratum.

Frora. The various kinds of trees and plants found in any
country constitute the flora of that country in the language
of botanists.

Fiuviatie. Belonging to a river. Etym., fluvius, a river.

FORAMINIFERA. A name given by D’Orbigny to a family of
microscopic shells, several of which are figured in Plate 13.
Vol. IV. p. 176. of this work. Their different chambers
are united by a small perforation or foramen. Recent ob-
servation has shown that some at least are not cephalopoda,
as D’ Orbigny supposed.

Formation. A group, whether of alluvial deposits, sedimentary
strata, or igneous rocks, referred to a common origin or
period.

Fossi All minerals were once called fossils, but geologists
now use the word only to express the remains of animals and
plants found buried in the earth. Etym., fossilis, any thing
that may be dug out of the earth.

Fossitirerous. Containing organic remains.

Gatena, A metallic ore, a compound of lead and sulphur. It
has often the appearance of highly polished lead. Etym.,
yarew, galeo, to shine.

Garner. A simple mineral, generally of a deep red colour,

uU 6

AAA, GLOSSARY.

crystallized ; most commonly met with in mica slate, but
also in granite and other igneous rocks.

Gasrerorops. A division of the Testacea in which, as in the
limpet, the foot is attached to the body. Etym., yaornp,
gaster, belly, and moda, poda, feet.

Gavia. A provincial name in the east of England for a series
of beds of clay and marl, the geological position of which is
between the upper and lower green-sand. See Table I. Fy
Vol. IV. p. 302.

Guo, or Gemmutr, from the Latin gemma, a bud. The term,
applied to zoophytes, means a young animal not confined
within an envelope or egg.

Gzotocy, Grocnosy. Both mean the same thing, but with an
unnecessary degree of refinement in terms, it has been pro-
posed to call our description of the structure of the earth
geognosy ( Etym., yea, gea, earth, and yivwoKw ginosco, to
know), and our theoretical speculations as to its formation
geology (Etym., yea, and Aoyos, logos, a discourse).

Gracer. Vast accumulations of ice and hardened snow in the
Alps and other lofty mountains. Etym., glace, French for
ice.

Gracis. A term borrowed from the language of fortification,
where it means an easy insensible slope or declivity, less
steep than a talus, which see.

Gneiss. A stratified primary rock, composed of the same
materials as granite, but having usually a larger proportion

of mica and a laminated texture. The word is a German
miner’s term.

Graminem. The order of plants to which grasses belong. Etym.,
gramen, grass.

Granite. An unstratified or igneous rock, generally found
inferior to or associated with the oldest of the stratified
rocks, and sometimes penetrating them in the form of dikes
and veins. .It is usually composed of three simple minerals,
felspar, quartz, and mica, and derives its name from having
a coarse granular structure; granum, Latin for grain.
Westminster, Waterloo, and London bridges, and the paving-
stones in the carriage-way of the London streets, afford good
examples of the most common varieties of granite.

Greensanp. Beds of sand, sandstone, limestone, belonging to

GLOSSARY. 445

the Cretaceous Period. See Table I. F, Vol. IV. p. 302.
The name is given to these beds because they often, but not
always, contain an abundance of green earth or chlorite
scattered through the substance of the sandstone, limestone,
&e. See Vol. IV. p. 271.

Greenstone. A variety of trap, composed of hornblende and
felspar.

Greywacké. Grauwacke, a German name, generally adopted
by geologists for the lowest members of the secondary strata.
Table I., O, Vol. IV. p. 306. ; see also Vol. IV. p. 297.
The rock is very often of a grey colour; hence the name,
grau, being German for grey, and wacke being a provincial

, miner’s term.

Grir. A provincial name for a coarse-grained sandstone.

Gyrsum. A mineral composed of lime and sulphuric acid, hence
called also sulphate of lime. Plaster and stucco are obtained
by exposing gypsum to a strong heat. It is found so abun-
dantly near Paris, that plaster of Paris is a common term in
this country for the white powder of which casts are made.
The term is used by Pliny for a stone used for the same
purposes by the ancients. The derivation is unknown.

Gvprsrovs, of or belonging to gypsum.

Gyroconrres. Bodies found in freshwater deposits, originally
supposed to be microscopic shells, but subsequently discovered
to be the seed-vessel of freshwater plants of the genus chara.
See Vol. III. p. 259. Etym., yupos, 8Y7s curved, and yovos,

gonos, seed, on account of their external structure.

Hemurrera. An order of insects, so called from a peculiarity in
their wings, the superior being coriaceous at the base, and
membranous at the apex, jmiov, hemisu, half, and mrepov,
pteron, wing.

Hornstenne. A simple mineral of a dark green or black colour,
which enters largely into the composition of several varieties
of the trap rocks.

Hornsrons. A siliceous mineral substance, sometimes approach-
ing nearly to flint, or common quartz. It has a conchoidal
fracture, and is infusible, which distinguishes it from com-
pact felspar.

Humerus. The bone of the upper arm.

446 GLOSSARY.,

Hypnoruytes. Plants which grow in water, Etym., úðwp,
hydor, water, and pvrov, phyton, plant.

Hyrocrxe Rocks.’ For an explanation of this term, see Vol. IV.
pee 1 9.

INCANDESCENT, White hot— having a more intense degree of
heat than red heat.

Iczzerg. Great masses of ice, often the size of hills, which float
in the polar and adjacent seas. Etym., ice, and berg, Ger-
man for hill.

Acuruvosaurus. A gigantic fossil marine reptile, intermediate
between a crocodile and a fish. Etym., ix@us, ichthus, a fish,
and cavpa, saura, a lizard.

Ienzous Rocxs. All rocks, such as lava, trap, and granite,
known or supposed to have been melted by volcanic heat.

Inpucrion. A consequence, inference, or general principle drawn
from a number of particular facts or phenomena. The
inductive philosophy, says Mr. Whewell, has been rightly
described as a science which ascends from particular facts to
general principles, and then descends again from these general
principles to particular applications.

Inrusory Anmmatcutes. Minute living creatures found in many
infusions ; and the term infusori has been given to all such
animalcules, whether found in infusions or in stagnant
water, vinegar, &c.

Insrissatep. Thickened. Etym., spissus, thick.

Inverresrarep ANIMALS. Animals which are not furnished
with a back-bone. For a further explanation, see “ Verte-
brated Animals.”

IsoruERMat. Such Zones or divisions of the land, ocean, or
atmosphere, which have an equal degree of mean annual
warmth, are said to be isothermal, from ‘os, isos, equal, and
Sepan, therme, heat,

Joints, JOINTED STRUCTURE, See « Cleavage,”

Jura Limestone. The limestones belonging to the Oolitic Group
(See Table I. H, Vol. IV. p. 303.) constitute the chief part of
the mountains of the Jura, between France and Switzerland ;
and hence the geologists of the Continent have given the
name to the group.

GLOSSARY. 4AT

Krimermer Cray. A thick ped of clay, constituting a member
of the Oolite Group. See Table I., H, Vol. IV. p. 303. So
called because it is found well developed at Kimmeridge in
the isle of Purbeck, Dorsetshire.

LACUSTRINE. Belonging to a lake. Etym., lacus, a lake.

LAMANTINE. A living species of the herbivorous cetacea or
whale tribe, which inhabits the mouths of rivers on the coasts
of Africa and South America : the sea-cow.

LAamELLITEROUS. Having a structure consisting of thin plates or
leaves like paper. ` Etym., lamella, the diminutive of lamina,
plate, and fero, to bear.

Lamina. Latin for plates ; used in geology, for the smaller
layers of which a stratum is frequently composed.

Lanpsurr. A portion of land that has slid down in conse-
quence of disturbance by an earthquake, or from being un-
dermined by water washing away the lower beds which
supported it.

Lariwirication — Lapidifying process. Conversion into stone.
Etym., lapis, stone, and fio, to make.

Lariti. Small volcanic cinders. Lapillus, a little stone.

Lava. The stone which flows in a melted state from a volcano.

Leucirs. A simple mineral found in volcanic rocks, crystallized,
and of a white colour. Etym., A€vKos, leucos, white.

Taal provincial name adopted in scientific language for a
particular kind of limestone, which, being characterized to-
gether with its associated beds, by peculiar fossils, forms a
particular group of the secondary strata. See Table I.,
Vol. IV. p. 304,

Lignirerpous. A term applied to insects which destroy wood.
Etym., lignum, wood, and perdo, to destroy.

Lucire. Wood converted into a kind of coal. Etym., lignum,
wood.

Lirnopomi. Molluscous animals which form holes in solid rocks
in which they lodge themselves. The holes are not perfo-
rated mechanically, but the rock appears to be dissolved.
Etym., NOOS, lithos, stone, and Seuw, demo, to build.

Litnocenovs Poryrs. Animals which form coral.

LITHOGRAPHIC STONE. A slaty compact limestone, of a yellowish
colour and fine grain, used in lithography, which is the art of

448 GLOSSARY.

drawing upon and printing from stone. Etym., Abos, lithos,
stone, and ypapw, grapho, to write.

Lirnowat. Having a stony structure.

Lirsonocicat. A term expressing the stony structure or charac-
ter of a mineral mass. We speak of the lithological character
of a stratum as distinguished from its zoological character.
Etym., rA.8os, lithos, stone, and Aoyos, logos, discourse.

Lirgornact. Molluscous animals which form holes in solid stones.
See “ Lithodomi.” Etym., Aibos, lithos, stone, and gayeiy,
phagein, to eat.

Lirnoruyres. The animals which form stone-coral. ;

Lirrorat. Belonging to the shore. Etym., littus, the shore.

Loam. A mixture of sand and clay.

Loruropoy. A genus of extinct quadrupeds, allied to the Tapir,
named from eminences on the teeth.

Lycoropiacrz. Plants of an inferior degree of organization to
Coniferze, some of which they very much resemble in foliage,
but all recent species are infinitely smaller. Many of the
fossil species are as gigantic as recent conifere. Their mode
of reproduction is analogous to that of ferns. In English
they are called club-mosses, generally found in mountainous
heaths in the north of England.

Lypran Srone. Flinty slate ; a kind of quartz or flint, allied to
hornstone, but of a greyish black colour.

Macieno. In Italy this term has been applied to a siliceous
sandstone sometimes containing calcareous grains, mica,
&c.

MADREPoRE. A genus of corals, but generally applied to all the
corals distinguished by superficial star-shaped cavities. There
are several fossil species,

MaenesiaN Limestone. An extensive series of beds, the geolo-
gical position ef which is immediately above the coal-mea-
sures; so Called because the limestone, the principal member
of the series, contains much of the earth magnesia as a con-
stituent part. See Table I. L, Vol. IV. p. 305.

Mammuirerous. Mammifers. Animals which give suck to their
young. To this class all the warm-blooded quadrupeds, and
the cetacea, or whales, belong. Etym., mamma, a breast,

Jero, to bear.

GLOSSARY. 449

MAMMILLARY. A surface which is studded over with rounded
projections. Etym., mammilla, a little breast or pap-

Mamoru. An extinct species of the elephant (E. primigenius),
of which the fossil bones are frequently met with in various
countries. The name is of Tartar origin, and is used in
Siberia for animals that burrow under ground.

Manatt One of the cetacea, the sea-cow or lamantine ( Tri-

chechus manatus, Lin.)

Mart. A mixture of clay and lime ; usually soft, but sometimes

hard, in which case it is called indurated marl.

Marsuriat Anmmats. A tribe of quadrupeds having a sack or
pouch under the belly, in which they carry their young» The
kangaroo is a well-known example. Etym., marsupium, &
purse.

Masropox. A genus of fossil extinct quadrupeds allied to the
elephants ; so called from the form of the hind teeth or grind-
ers, which have their surface covered with conical mam-
millary crests. Etym., macros, mastos, pap, and odwy, odon,
tooth.

Marri. Ifa simple mineral or shell, in place of being detached,
be still fixed in a portion of rock, it is said to be in its matrix.
Matrix, womb.

MECHANICAL ORIGIN, Rocxs or. Rocks composed of sand, peb-
bles, or fragments, are so called, to distinguish them from
those of a uniform crystalline texture, which are of chemical
origin.

Menusa. A genus of marine radiated animals, without shells ;
so called because their organs of motion spread out like the
snaky hair of the fabulous Medusa.

Mxcatosaurus. A fossil gigantic amphibious animal of the
saurian or lizard and crocodile tribe. Etym., peyan, megale,

5 great, und cavpa, saura, lizard.

MEGATHERIUM. A fossil extinct quadruped, resembling a gigantic
sloth. Etym., BEY% mega, great, and Onpiov, therion, wild
beast.

Metastoma. A genus of MELASTOMACEA, an order of exotic
plants of the evergreen tree, and shrubby kinds. Etym.,
peras, melas, black, and oroua, stoma, mouth; because the
fruit of one of the species stains the lips.

4.50 GLOSSARY.

Mesorvrz. A simple mineral, white, and needle-shaped, one of
the Zeolite family, frequently met with in the trap-rocks.
Meramorraic Rocks. For an explanation of this term, see
Vol. IV. p. 380.

.Mica. A simple mineral, having a shining silvery surface, and
capable of being split into very thin elastic leaves or scales.
It is often called talc, in common life; but mineralogists apply
the term talc to a different mineral. The brilliant scales in
granite are mica. Etym., mico, to shine.

Mica-statz, Muica-scutst, Micacrous Scuistus. One of the
lowest of the stratified rocks, belonging to the hypogene or
primary class, which is characterized by being composed of a
large proportion of mica united with quartz.

Miocenr. See an explanation of this term, Vol. III. p. 370.

Motassr. A provincial name for a soft green sandstone, associ-
ated with marl and conglomerates, belonging to the Miocene
Tertiary Period, extensively developed in the lower country
of Switzerland. See Vol. IV. p. 128. Etym., French,
molle, soft.

Morrusca, Morrtuscous Anrmats. Animals, such as shell-fish,

which, being devoid of bones, have soft bodies. Etym.,

mollis, soft. i
Moxa. The smallest of visible animalcules, spoken of by Buffon

and his followers as constituting the elementary molecules of

organic beings,

Moniror. An animal of the saurian or lizard tribe, species of
which are found in both the fossil and recent state.

Monocoryiepvonous. A grand division of the vegetable kingdom
(including palms, grasses, lilaceze, &c.), founded on the plant
having only one cotyledon, or seed lobe. Etym., povos, Monos,
single.

Moscuus. A quadruped resembling the chamois or mountain
goat, from which the perfume musk is obtained.

Mountain Limestone. A series of limestone strata, of which the
geological position is immediately below the coal measures,
and with which they also sometimes alternate. See Table I.,
M, Vol. IV. p. 305.

Moya. A term applied in South America to mud poured out
from volcanos during eruptions.

GLOSSARY. 451

MULTILOCULAR. Many-chambered, a term applied to those shells
which, like the nautilus, ammonite, and others, are divided
into many compartments. Etym., multus, many, and loculus,
a partition.

Murare or Sopa. The scientific name for common culinary salt,
because it is composed of muriatic acid and the alkali soda.

Musacem A family of tropical monocotyledonous plants, in-
cluding the banana and plaintains.

Muscuerxatx. A limestone which, in geological position, belongs
to the red sandstone group. This formation has not yet been
found in England, and the German name is adopted by En-
glish geologists. The word means shell-limestone. Etym.,
muschel, shell, and kalkstein, limestone. See Table I., K,
Vol. IV. p. 305.

Naprutaa. Avery thin, volatile, inflammable, and fluid mineral
substance, of which there are springs in many countries,
particularly in volcanic districts.

Nenvrsar. A yellow water-lily.

New Rep Sanpstone. A series of sandy and argillaceous strata,
the predominant colour of which is brick-red, but containing
portions which are of a greenish grey. These occur often

’ in spots and stripes, so that the series has sometimes been
called the variegated sandstone. ‘The European formation
so called lies in a geological position immediately above the
magnesian limestone. See Table I., K, Vol. IV. p. 304+

Noputz. A rounded irregular-shaped lump or mass. Etym.
diminutive of nodus, knot.

Normat Groves. Groups of certain rocks taken as a rule or
standard. Etym., norma, rule or pattern.

Nucrevs. A solid central piece, around which other matter is
collected. The word is Latin for kernel.

Noumuoures. An extinct genus of the order of molluscous:
animals called Cephalopoda, of a thin lenticular shape, in-
ternally divided into small chambers. Etym., NUMMUS, Latin
for money, and Apos, lithos, stone, from its resemblance to a

coin.

Ozsīnran. A volcanic product, or species of lava, very like com-

mon green bottle-glass, which is almost black in large masses,

GLOSSARY.

but semi-transparent in thin fragments. Pumice-stone is
obsidian in a frothy state ; produced, most probably, by water
that was contained in or had access to the melted stone, and
converted into steam. There are very often portions in
masses of solid obsidian, which are partially converted into
pumice. .

Ocyvcian DELUGE. A great inundation mentioned in fabulous
history, supposed to have taken place in the reign of Ogyges
in Attica, whose death is fixed in Blair’s Chronological
Tables in the year 1764 before Christ.

Orp Rep Sannsronz. A stratified formation immediately below
the Carboniferous Group, and sometimes classed with it.
See Table I., N, Vol. IV. p. 306.

Ouivine. An olive-coloured, semi-transparent, simple mineral,
very often occurring in the form of grains and of crystals in
basalt and lava.

Oourr, Oore. A limestone, so named because it is composed
of rounded particles, like the roe or eggs of a fish. The
name is also applied to a large group of strata, Table I., H,
Vol. IV. p. 303. characterized by peculiar fossils, because

limestone of this kind occurs in this group in England, France,
&c. Etym., wov, oon, egg, and Abos, lithos, stone.

Oratizep Woop. Wood petrified by siliceous earth, and ac-
quiring a structure similar to the simple mineral called
opal.

Opuipious Rerrizes. Vertebrated animals, such as snakes and
Serpents. Etym., opis, ophis, a serpent.

Oxcanic Remains. The remains of animals and plants (organ-
‘ized bodies) found in a fossil state. ;

ORTHOCERATA, or ORrTHOCERÆ. An extinct genus of the order of
molluscous animals, called Cephalopoda, that inhabited a
Jong-chambered conical shell, like a straight horn. Etym.,
op§os, orthos, straight, and repas, ceras, horn.

Osszous Breccia. The cemented mass of fragments of bones of
extinct animals found in caverns and fissures. Osseus is a
Latin adjective, signifying bony.

Osrrotocy. That division of anatomy which treats of the bones :
from ooreoy, osteon, bone, and Aovyos, logos, a discourse.

Ovrtiers. When a portion of a stratum occurs at some distance,
detached from the general mass of the formation to which it

GLOSSARY. ` 453

belongs, some practical mineral surveyors call it an outlier,
; and the term is adopted in geological language.
Ovate. The shape of an egg. Etym., ovum, egg.

Ovirositine. The laying of eggs.

Oxinr. The combination of a metal with oxygen ; rust is oxide
of iron.

Oxycen. One of the constituent parts of the air of the atmo-
sphere ; that part which supports life. For a further explan-
ation of the word, consult elementary works on chemistry.

Pacuypermata. An order of quadrupeds, including the elephant,
rhinoceros, horse, pig, &c., distinguished by having thick
skins. Etym., Taxus, pachus, thick, and Sepua, derma, skin,
or hide.

Pacuypermatous. Belonging to pachydermata.

PALÆOTHERIUM, PALEOTHERE, A fossil extinct quadruped, be-
longing to the order Pachydermata, resembling a pig, or
tapir, but of great size. Etym., TAAQIOS, palaios, ancient,
and Snpiov, therion, wild beast.

Patzonronocy. The science which treats of fossil remains, both
animal and vegetable. Etym., waAaios, pelaios, ancient,
ovra, onta, beings, and Aoyos, logos, a discourse.

PELAGIAN, PELAGIC. Belonging to the deep sea. Etym., pela-
gus, Sea. $ i

Pererino. An Italian name for a particular kind of volcanic
` rock, formed, like tuff, by the cementing together of volcanic
sand, cinders, or scoriæ, &c.

Perroteum. A liquid mineral pitch, so called because it is seen to
ooze like oil outof the rock. Etym., petra, rock, and oleum, oil.

Puxnocamous or Paanerocamic Prants. A name given by
Linnzeus to those plants in which the reproductive organs
are apparent. Etym., pavepos, phaneros, evident, or paiva,
phaino, to show, and yapos, gamos, marriage.

Putrcrman Freups. Campi Phlegrai, or “ the Burnt Fields.”
The country around Naples, so named by the Greeks, from
the traces of igneous action every where visible.

Puonoutse. See “ Clinkstone.”

Purycanza. A genus of four-winged insects, the larvæ of which,
called caddis worms, are used by anglers as a bait.

Puysics. The department of science which treats of the proper-

ABA. GLOSSARY.

ties of natural bodies, laws of motion, &c. ; sometimes called
natural philosophy and mechanical philosophy. Etym.,
gvots, physis, nature.

Purrotocy, Puyronocicat. The department of science which
relates to plants — synonymous with botany and botanical.
Etym., pvrov, phyton, plant, and Aoyos, logos, discourse.

Puytornacous. Plant-eating. Etym., pvrov, phyton, plant, and
garyew, phagein, to eat.

Pisouirz. A stone possessing a structure like an agglutination
of pease. Etym., micov, pison, pea, and Abos, lithos, stone.

Pistia. Vol. III. p. 42. The plant mentioned by Malte-Brun
is probably the Pistia Stratiotes, a floating plant, related to
English duck-weed, but very much larger.

Pir Coat. Ordinary coal; called so because it is obtained by
sinking pits in the ground.

Pircustone. A rock of a uniform texture, belonging to the
unstratified and volcanic classes, which has an unctuous ap-
pearance like indurated pitch.

Prastic Cray. One of the beds of the Eocene Tertiary Period
(see Table I., E, Vol. IV. p. 302.), so called because it is
used for making pottery. The formation to which this
name is applied is a series of beds chiefly sands, with which
the clay is associated. Etym., wAacow, plasso, to form or
fashion.

Puzstosaurus. A fossil extinct amphibious animal, resembling
the saurian, or lizard and crocodile tribe. Etym., wAnovoy,
plesion, near to, and savpa, saura, a lizard.

Puiocenr. See explanation of this term, Vol. IIT. p. 368.

Piuronic Rocks. Granite, porphyry,:and other igneous rocks,
supposed to have consolidated from a melted state at a great
depth from the surface. For an explanation of this term,
see Vol. IV. p. 337.

Porypanta. Corats. A numerous class of invertebrated
animals, belonging to the great division called Radiata.

Porruyry. An unstratified or igneous rock. The term is as
old as the time of Pliny, and was applied to a red rock with
small, angular, white bodies diffused through it, which are
crystallized felspar, brought from Egypt. The term is hence
applied to every species of unstratified rock in which de-
tached crystals of felspar or some other mineral are diffused

GLOSSARY. 455

through a base of other mineral composition. Etym.,
moppupa, porphyras purple.

PORTLAND LIMESTONE, PORTLAND Brps. A series of limestone
strata, belonging to the upper part of the Oolite Group (see
Table I., H, Vol. IV. p. 303.), found chiefly in England
in the Island of Portland on the coast of Dorsetshire. Tke
great supply of the building stone used in London is from

these quatries.

PozzvOLANA. Volcanic ashes, largely used. as mortar for build-
ings, similar in nature to what is called in this country Roman
cement. It gets its name from Pozzuoli, a town in the bay _
of Naples, from which it is shipped in large quantities to all
parts of the Mediterranean.

Precremare. Substances which having been dissolved in a
fluid, are separated from it by combining chemically and
forming a solid, which falls to the bottom of the fluid. This
process is the opposite to that of chemical solution.

Propucra. An extinct genus of fossil bivalve shells, occurring
only in the older secondary rocks. It is closely allied to the
living genus Terebratula.

Pususcence. The soft hairy down on insects. Etym., pubesco,
the first growth of the beard.

PupprncstonE. See ‘ Conglomerate.”

Pumice. A light spongy lava, chiefly felspathic, of a white colour,
produced by gases, or watery vapour getting access to the
particular kind of glassy lava called obsidian, when in a state
of fusion — it may be called the froth of melted volcanic
glass. ‘The word comes from the Latin name of the stone,
pumer.

Purseck LIMESTONE, Purseck Beps. Limestone strata belong-
ing to the Wealden Group. See Table I. G, Vol. IV. p. 303.

Pyarires (Iron). A compound of sulphur and iron, found usually
in yellow shining crystals like brass, and in almost every rock,
stratified and unstratified. The shining metallic bodies,
so often seen in common roofing slate, are a familiar example
of the mineral. The word is Greek, and comes from up,
pyr, fire; because, under particular circumstances, the stone
produces spontaneous heat, and even inflammation.

Pyromerer. An instrument for measuring intense degrees of
heat.

456 GLOSSARY.

Quaprumana. The order of mammiferous animals to which apes
belong. Etym., quadrus, a derivative of the Latin word for
the number four, and manus, hand ; the four feet of those
animals being in some degree usable as hands.

Qua-Qua-vERSAL Dır. The dip of beds to all points of the com-
pass around a centre, as in the case of beds of lava round
the crater of a volcano, Etym., qud-qué versum, on every
side.

Quartz. A German provincial term, universally adopted in
scientific language for a simple mineral composed of pure
silex, or earth of flints: rock-crystal is an example.

Rep Marz. A term often applied to the New Red Sandstone,
which is the principal member of the Red Sandstone Group.
See Table I., K, Vol. IV. p. 304.

Rericutats. A structure of cross lines, like a net, is said to be
reticulated, from rete, a net.

Rock Sarm. Common culinary salt, or muriate of soda, found
in vast solid masses or beds, in different formations, exten-
sively in the New Red Sandstone formation, as in Cheshire ;
and it is then called rock-salt.

Rumrxayria. Animals which ruminate or chew the cud, such
as the ox, deer, &c. Etym., the Latin verb rumino, meaning
the same thing.

SaccHarorp, SaccHarine. When a stone has a texture resem-
pling that of loaf-sugar. Etym., caxxap, sacchar, sugar, and.

eiðos, eidos, form.
IENT E. .
er AS Fig. 24.
In a zigzag

; A a a a a

ine, aa ar oN Si \

„the ; salient Wes N4 Hi RAS R £ n2
angles, bb -

the re-entering angles. Etym., salire, to leap or bound for-

ward.

Sarr Sprines. Springs of water containing a large quantity of
common salte They are very abundant in Cheshire and
Worcestershire, and culinary salt is obtained from them by
mere evaporation.

Sanpstone. Any stone which is composed of an agglutination

GLOSSARY. 457

of grains of sand, whether calcareous, siliceous, or of any
other mineral nature.

Saurran. Any animal belonging to the lizard tribe. Etym.>
caupa, SAUTA, a lizard.

Scuist is often used as synonymous with slate ; but it may be very
useful to distinguish between a schistose and a slaty structure.
The granitic or primary schists, as they are termed, such as
gneiss, mica-schist, and others, cannot be split into an inde-
finite number of parallel lamine, like rocks which have a true
slaty cleavage. The uneven schistose layers of mica-schist
and gneiss are probably layers of deposition which have
assumed a crystalline texture. See “ Cleavage.” Etym.,
schistus, adj. Latin; that which may be split.

Scuistosr Rocks. See * Schist.”

Scorta. Volcanic cinders. The word is Latin for cinders.

Szams. Thin layers which separate two strata of greater magni-
tude.

Seconpary Srrata. An extensive series of the stratified rocks

\
which compose the crust of the globe, with certain characters

in common, which distinguish them from another series
below them called primary, and from a third series above
them called tertiary. See Vol. IV. p. 268., and Table I.
VolorVe pe 302?

SECULAR REFRIGERATION. The periodical cooling and consoli-
dation of the globe from a supposed original state of fluidity
from heat. Sceculum, age or period.

Sepumentary Rocks, are those which have been formed by their
materials having been thrown down from a state of suspen-
sion or solution in water.

Setenire. Crystallized gypsum, or sulphate of lime — a simple
mineral.

Sepraria. Flattened balls of stone, generally a kind of iron-
stone, which, on being split, are seen to be separated in their
interior into irregular masses. Etym., septa, inclosures.

SERPENTINE, A rock usually containing much magnesian earth,
for the most part unstratified, but sometimes appearing to be
an altered or metamorphic stratified rock. Its name is de-
rived from frequently presenting contrasts of colour, like the
skin of some serpents.

VOL. I. x

458 GLOSSARY.

Saare. A provincial term, adopted by geologists, to express an
indurated slaty clay. Etym., German schalen, to peel, to split.

Sarit Mart. <A deposit of clay, peat, and other substances
mixed with shells, which collects at the bottom of lakes.

Suinexze. ‘The loose and completely water-worn gravel on the
sea-shore,

Sex. The name of one of the pure earths, being the Latin
word for flint, which is wholly composed of that earth.
French geologists have applied it as a generic name for all
minerals composed entirely of that earth, of which there are
many of different external forms.

Smica. One of the pure earths. Etym., silex, flint, because
found in that mineral.

Sıurcare. A chemical compound of silica and another substance,
such as silicate of iron. Consult elementary works on che-
mistry.

Suiceous. Of or belonging to the earth of flint. ` Etym., silex,
which see. A siliceous rock is one mainly composed of silexe

Suicirrep, Any substance that is petrified or mineralized by
siliceous earth, 3 i

Sır. The more comminuted sand, clay, and earth, which is
transported by running water. It'is often accumulated by
currents in banks. Thus the mouth of a river is silted up
when it entrance into the sea is impeded by such accumu-
lation of loose materials.

Simere Mineran. Individual mineral substances, as distin-
guished from rocks, which last are usually an aggregation of
simple minerals. They are not simple in regard to their
nature; for, when subjected to chemical analysis, they are
found to consist of a variety of different substances. Pyrites
is a simple mineral in the sense we use the term, but it is a

-

chemical compound of sulphur and iron.
Stare. See “ Cleavage” and “ Schist.”’
Sorrarara. A volcanic vent from which sulphur, sulphureous,

watery, and acid vapours and gases are emitted.
Srornutes. The reproductory corpuscula (minute bodies) of
cryptogamic plants. Etym., omopa, spora, a seed.
Srauactire. When water holding lime in solution deposits it as
it drops from the roof of a cavern, long rods of stone hang

GLOSSARY. 459

down like icicles, and these are called stalactites. Etym.,
oraragw, stalaxo, to drop. tes.

Sratacmire. When water holding lime in solution drops on
the floor of a cavern, the water evaporating leaves a crust
composed of layers of limestone : such a crust is called stalag-
mite, from oradarypa, stalagma, a drop, in opposition to sta-
lactite, which see.

Sravican Figure. The figure which results from the equilibrium
of forces. From oraros, statos, stable, or standing still.
Srernum. The breast bone, or the flat bone occupying the

front of the chest.

Srmsirs. A crystallized simple mineral, usually white, one of
the Zeolite family, frequently included in the mass of the
trap rocks.

Srratirren. Rocks arranged in the form of strata, which see.

Srratirication. An arrangement of rocks in strata, which see.

Srrata, Stratum. The term stratum, derived from the Latin

verb struo, to strew or lay out, means a bed or mass of matter
spread out over a certain surface by the action of water, or in
some cases by wind, The deposition of successive layers of
sand and gravel in the bed of a river, or in a canal, affords a
perfect illustration both of the form and origin of stratification.
A large portion of the masses constituting the earth’s crust
are thus stratified, the successive strata of a given rock pre-
serving a general parallelism to each other; but the planes
of stratification not being perfectly parallel throughout a
great extent like the planes of cleavage, which see.

Srrixz. The direction or line of bearing of strata, which is
always at right angles to their prevailing dip. For a fuller
explanation, see Vol. IV. p. 331.

Suzarennines. Low hills which skirt or lie at the foot of the
great chain of the Apennines in Italy. The term Subapen-
nine is applied geologically to a series of strata of the Older
Pliocene period.

Syenite. A kind of granite, so called because it was brought
from Syene in Egypt. For geological acceptation of the
term, see Vol. IV. p. 344.

Sywotrnat Axis. See “ Anticlinal.” Etym., ovr, syn, together,
and KAww, clino, to incline.

X2

460 GLOSSARY.

Tarus. -When fragments are broken off by the action of the
weather from the face of a steep rock, as they accumulate
at its foot, they form a sloping heap, called a talus. The
term is borrowed from the language of fortification, where
talus means the outside of a wall of which the thickness is
diminished by degrees, as it rises in height, to make it the
firmer. X

Tarst. The feet in insects, which are articulated, and formed
of five or a less number of joints:

Trerrary Strata. A series of sedimentary rocks, with charac-
ters which distinguish them from two other great serie

of strata — the secondary and primary — which lie beneath

them.

Trstacea. Molluscous animals, having a shelly covering. Etym.,
testa, a shell, such as snails, whelks, oysters, &c.

Turrmat Hot. Etym., Depos, thermos, hot.

THERMO-ELECTRICITY. Electricity developed by heat.

Tur ovr. When a stratum, in the course of its prolongation in
any direction, becomes gradually less in thickness, the two
surfaces approach nearer and nearer ; and when at last they
meet, the stratum is said to thin out or disappear.

Tracuyte. A variety of lava essentially composed of glassy
felspar, and frequently having detached crystals of felspar in
the base or body of the stone, giving it the structure of por-
phyry. It sometimes contains hornblende and augite ; and
when these last predominate, the trachyte passes into the
varieties of trap called greenstone, basalt, dolorite, &c.» The
term is derived from tpaxus, trachus, rough, because the rock
has a peculiar rough feel. ;

Tprar and Trarrran Rocks. Volcanic rocks composed of felspar,
-augite, and hornblende. The various proportions and state
of aggregation of these simple minerals, and differences in
external forms, give rise to varieties, which have received
distinct appellations, such as basalt, amygdaloid, dolorite
greenstone, and others. The term is derived from trappa,
a Swedish word for stair, because the rocks of this class
sometimes occur in large tabular masses, rising one above
another, like. steps. For further explanation, see Vol. IV.
p. 346.

GLOSSARY. 461

Travertin. A concretionary limestone, usually hard and semi-
crystalline, deposited from the water of springs holding lime
in solution. — Etym. This stone was called by the ancients
Lapis Tiburtinus, the stone being formed in great quantity
by the river Anio, at Tibur, near Rome. Some suppose
travertin to be an abbreviation of trasteverino from trans-
tiburtinus.

Tror, of Insects. Organs which form the mouth, consisting of
an upper and under lip, and comprising the parts called
mandibles, maxilla, and palpi.

Tura, Catcarzous. A porous rock deposited by calcareous
waters on their exposure to the air, and usually containing
portions of plants and other organic substances incrusted
with carbonate of lime. The more solid form of the same
deposit is called “ travertin,” into which it passes.

Tura, Voucanic. See “ Tuff.”

Turaczous. A rock with the texture of tuff or tufa, which see.

Turr or Tura, Vortcayic. An Italian name for a variety of
volcanic rock of an earthy texture, seldom very compact, and.
composed of an agglutination of fragments of scoriz and
loose matter ejected from a volcano.

TURBINATED. Shells which have a spiral or screw-form structure.
Etym., turbinatus, made like a top. ;

UNCONFORMABLE. See “ Conformable.”’

UNOXIDIZED, UNoxIDATED. Not combined with oxygen.

Verns, MINERAL. Cracks in rocks filled up by substances different
from the rock, which may either be earthy or metallic. Veins

are sometimes many yards wide; and they ramify or branch
off into innumerable smaller parts, often as slender as threads,
like the veins in an animal, hence their name.

VERTEBRATED ANIMALS. A great division of the animal king-
dom, including all those which are furnished with a back-
bone, aş the mammalia, birds, reptiles, and fishes. The
separate joints of the back-bone are called vertebre, from the
Latin verb verio, to turn.

Vesrcre. A small, circular, inclosed space, like a little bladder.
Etym., diminutive of vesica, Latin for a bladder.

462 GLOSSARY.

Virairication. The conversion of a body into glass by heat.

Voucanic Bomss. Volcanos throw out sometimes detached
masses of melted lava, which, as they fall, assume rounded
forms (like bomb-shells), and are often elongated into a pear
shape.

Voucanic Foci. , The subterranean centres of action in volcanos,
where the heat is supposed to be in the highest degree of

energy.

Wacxe. A rock nearly allied to basalt, of which it may be re-
garded as a soft and earthy variety.

Zeotrre. A family of simple minerals, including stilbite, meso-
type, analcime, and some others, usually found in the trap or
volcanic rocks. Some of the most common varieties swell or
boil up when exposed to the blow-pipe, and hence the name
of few, zeo, to boil, and Abos, lithos, stone.

Zooruytes. Corals, sponges, and other aquatic animals allied to
them ; so called because, while they are the habitation of
animals, they are fixed to the ground, and have the forms of
plants. Etym., §wov, zoon, animal, and gutov, phyton,
plant.

END OF THE FIRST VOLUME.

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